6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
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16 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès@*
17 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
18 Copyright @copyright{} 2013 Nikita Karetnikov@*
19 Copyright @copyright{} 2014, 2015, 2016 Alex Kost@*
20 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
21 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
22 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
23 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
24 Copyright @copyright{} 2015, 2016, 2017 Ricardo Wurmus@*
25 Copyright @copyright{} 2016 Ben Woodcroft@*
26 Copyright @copyright{} 2016 Chris Marusich@*
27 Copyright @copyright{} 2016, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016, 2017 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert@*
38 Copyright @copyright{} 2017 humanitiesNerd@*
39 Copyright @copyright{} 2017 Christopher Allan Webber@*
40 Copyright @copyright{} 2017 Marius Bakke@*
41 Copyright @copyright{} 2017 Hartmut Goebel@*
42 Copyright @copyright{} 2017 Maxim Cournoyer@*
43 Copyright @copyright{} 2017 Tobias Geerinckx-Rice
45 Permission is granted to copy, distribute and/or modify this document
46 under the terms of the GNU Free Documentation License, Version 1.3 or
47 any later version published by the Free Software Foundation; with no
48 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
49 copy of the license is included in the section entitled ``GNU Free
50 Documentation License''.
53 @dircategory System administration
55 * Guix: (guix). Manage installed software and system configuration.
56 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
57 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
58 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
59 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
62 @dircategory Software development
64 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
65 * guix build: (guix)Invoking guix build. Building packages.
66 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
70 @title GNU Guix Reference Manual
71 @subtitle Using the GNU Guix Functional Package Manager
72 @author The GNU Guix Developers
75 @vskip 0pt plus 1filll
76 Edition @value{EDITION} @*
84 @c *********************************************************************
88 This document describes GNU Guix version @value{VERSION}, a functional
89 package management tool written for the GNU system.
92 * Introduction:: What is Guix about?
93 * Installation:: Installing Guix.
94 * Package Management:: Package installation, upgrade, etc.
95 * Programming Interface:: Using Guix in Scheme.
96 * Utilities:: Package management commands.
97 * GNU Distribution:: Software for your friendly GNU system.
98 * Contributing:: Your help needed!
100 * Acknowledgments:: Thanks!
101 * GNU Free Documentation License:: The license of this manual.
102 * Concept Index:: Concepts.
103 * Programming Index:: Data types, functions, and variables.
106 --- The Detailed Node Listing ---
110 * Binary Installation:: Getting Guix running in no time!
111 * Requirements:: Software needed to build and run Guix.
112 * Running the Test Suite:: Testing Guix.
113 * Setting Up the Daemon:: Preparing the build daemon's environment.
114 * Invoking guix-daemon:: Running the build daemon.
115 * Application Setup:: Application-specific setup.
117 Setting Up the Daemon
119 * Build Environment Setup:: Preparing the isolated build environment.
120 * Daemon Offload Setup:: Offloading builds to remote machines.
124 * Features:: How Guix will make your life brighter.
125 * Invoking guix package:: Package installation, removal, etc.
126 * Substitutes:: Downloading pre-built binaries.
127 * Packages with Multiple Outputs:: Single source package, multiple outputs.
128 * Invoking guix gc:: Running the garbage collector.
129 * Invoking guix pull:: Fetching the latest Guix and distribution.
130 * Invoking guix pack:: Creating software bundles.
131 * Invoking guix archive:: Exporting and importing store files.
133 Programming Interface
135 * Defining Packages:: Defining new packages.
136 * Build Systems:: Specifying how packages are built.
137 * The Store:: Manipulating the package store.
138 * Derivations:: Low-level interface to package derivations.
139 * The Store Monad:: Purely functional interface to the store.
140 * G-Expressions:: Manipulating build expressions.
144 * package Reference :: The package data type.
145 * origin Reference:: The origin data type.
149 * Invoking guix build:: Building packages from the command line.
150 * Invoking guix edit:: Editing package definitions.
151 * Invoking guix download:: Downloading a file and printing its hash.
152 * Invoking guix hash:: Computing the cryptographic hash of a file.
153 * Invoking guix import:: Importing package definitions.
154 * Invoking guix refresh:: Updating package definitions.
155 * Invoking guix lint:: Finding errors in package definitions.
156 * Invoking guix size:: Profiling disk usage.
157 * Invoking guix graph:: Visualizing the graph of packages.
158 * Invoking guix environment:: Setting up development environments.
159 * Invoking guix publish:: Sharing substitutes.
160 * Invoking guix challenge:: Challenging substitute servers.
161 * Invoking guix copy:: Copying to and from a remote store.
162 * Invoking guix container:: Process isolation.
163 * Invoking guix weather:: Assessing substitute availability.
165 Invoking @command{guix build}
167 * Common Build Options:: Build options for most commands.
168 * Package Transformation Options:: Creating variants of packages.
169 * Additional Build Options:: Options specific to 'guix build'.
170 * Debugging Build Failures:: Real life packaging experience.
174 * System Installation:: Installing the whole operating system.
175 * System Configuration:: Configuring the operating system.
176 * Documentation:: Browsing software user manuals.
177 * Installing Debugging Files:: Feeding the debugger.
178 * Security Updates:: Deploying security fixes quickly.
179 * Package Modules:: Packages from the programmer's viewpoint.
180 * Packaging Guidelines:: Growing the distribution.
181 * Bootstrapping:: GNU/Linux built from scratch.
182 * Porting:: Targeting another platform or kernel.
186 * Limitations:: What you can expect.
187 * Hardware Considerations:: Supported hardware.
188 * USB Stick Installation:: Preparing the installation medium.
189 * Preparing for Installation:: Networking, partitioning, etc.
190 * Proceeding with the Installation:: The real thing.
191 * Installing GuixSD in a VM:: GuixSD playground.
192 * Building the Installation Image:: How this comes to be.
196 * Using the Configuration System:: Customizing your GNU system.
197 * operating-system Reference:: Detail of operating-system declarations.
198 * File Systems:: Configuring file system mounts.
199 * Mapped Devices:: Block device extra processing.
200 * User Accounts:: Specifying user accounts.
201 * Locales:: Language and cultural convention settings.
202 * Services:: Specifying system services.
203 * Setuid Programs:: Programs running with root privileges.
204 * X.509 Certificates:: Authenticating HTTPS servers.
205 * Name Service Switch:: Configuring libc's name service switch.
206 * Initial RAM Disk:: Linux-Libre bootstrapping.
207 * Bootloader Configuration:: Configuring the boot loader.
208 * Invoking guix system:: Instantiating a system configuration.
209 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
210 * Defining Services:: Adding new service definitions.
214 * Base Services:: Essential system services.
215 * Scheduled Job Execution:: The mcron service.
216 * Log Rotation:: The rottlog service.
217 * Networking Services:: Network setup, SSH daemon, etc.
218 * X Window:: Graphical display.
219 * Printing Services:: Local and remote printer support.
220 * Desktop Services:: D-Bus and desktop services.
221 * Database Services:: SQL databases, key-value stores, etc.
222 * Mail Services:: IMAP, POP3, SMTP, and all that.
223 * Messaging Services:: Messaging services.
224 * Telephony Services:: Telephony services.
225 * Monitoring Services:: Monitoring services.
226 * Kerberos Services:: Kerberos services.
227 * Web Services:: Web servers.
228 * DNS Services:: DNS daemons.
229 * VPN Services:: VPN daemons.
230 * Network File System:: NFS related services.
231 * Continuous Integration:: The Cuirass service.
232 * Power management Services:: The TLP tool.
233 * Audio Services:: The MPD.
234 * Virtualization Services:: Virtualization services.
235 * Miscellaneous Services:: Other services.
239 * Service Composition:: The model for composing services.
240 * Service Types and Services:: Types and services.
241 * Service Reference:: API reference.
242 * Shepherd Services:: A particular type of service.
246 * Software Freedom:: What may go into the distribution.
247 * Package Naming:: What's in a name?
248 * Version Numbers:: When the name is not enough.
249 * Synopses and Descriptions:: Helping users find the right package.
250 * Python Modules:: A touch of British comedy.
251 * Perl Modules:: Little pearls.
252 * Java Packages:: Coffee break.
253 * Fonts:: Fond of fonts.
257 * Building from Git:: The latest and greatest.
258 * Running Guix Before It Is Installed:: Hacker tricks.
259 * The Perfect Setup:: The right tools.
260 * Coding Style:: Hygiene of the contributor.
261 * Submitting Patches:: Share your work.
265 * Programming Paradigm:: How to compose your elements.
266 * Modules:: Where to store your code?
267 * Data Types and Pattern Matching:: Implementing data structures.
268 * Formatting Code:: Writing conventions.
273 @c *********************************************************************
275 @chapter Introduction
278 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
279 using the international phonetic alphabet (IPA).} is a package
280 management tool for the GNU system. Guix makes it easy for unprivileged
281 users to install, upgrade, or remove packages, to roll back to a
282 previous package set, to build packages from source, and generally
283 assists with the creation and maintenance of software environments.
285 @cindex user interfaces
286 Guix provides a command-line package management interface
287 (@pxref{Invoking guix package}), a set of command-line utilities
288 (@pxref{Utilities}), as well as Scheme programming interfaces
289 (@pxref{Programming Interface}).
291 Its @dfn{build daemon} is responsible for building packages on behalf of
292 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
293 binaries from authorized sources (@pxref{Substitutes}).
295 @cindex extensibility of the distribution
296 @cindex customization, of packages
297 Guix includes package definitions for many GNU and non-GNU packages, all
298 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
299 user's computing freedom}. It is @emph{extensible}: users can write
300 their own package definitions (@pxref{Defining Packages}) and make them
301 available as independent package modules (@pxref{Package Modules}). It
302 is also @emph{customizable}: users can @emph{derive} specialized package
303 definitions from existing ones, including from the command line
304 (@pxref{Package Transformation Options}).
306 @cindex Guix System Distribution
308 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
309 where it complements the available tools without interference
310 (@pxref{Installation}), or you can use it as part of the standalone
311 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
312 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
313 system configuration and Guix takes care of instantiating the
314 configuration in a transactional, reproducible, and stateless fashion
315 (@pxref{System Configuration}).
317 @cindex functional package management
318 Under the hood, Guix implements the @dfn{functional package management}
319 discipline pioneered by Nix (@pxref{Acknowledgments}).
320 In Guix, the package build and installation process is seen
321 as a @emph{function}, in the mathematical sense. That function takes inputs,
322 such as build scripts, a compiler, and libraries, and
323 returns an installed package. As a pure function, its result depends
324 solely on its inputs---for instance, it cannot refer to software or
325 scripts that were not explicitly passed as inputs. A build function
326 always produces the same result when passed a given set of inputs. It
327 cannot alter the environment of the running system in
328 any way; for instance, it cannot create, modify, or delete files outside
329 of its build and installation directories. This is achieved by running
330 build processes in isolated environments (or @dfn{containers}), where only their
331 explicit inputs are visible.
334 The result of package build functions is @dfn{cached} in the file
335 system, in a special directory called @dfn{the store} (@pxref{The
336 Store}). Each package is installed in a directory of its own in the
337 store---by default under @file{/gnu/store}. The directory name contains
338 a hash of all the inputs used to build that package; thus, changing an
339 input yields a different directory name.
341 This approach is the foundation for the salient features of Guix: support
342 for transactional package upgrade and rollback, per-user installation, and
343 garbage collection of packages (@pxref{Features}).
346 @c *********************************************************************
348 @chapter Installation
350 @cindex installing Guix
351 GNU Guix is available for download from its website at
352 @url{http://www.gnu.org/software/guix/}. This section describes the
353 software requirements of Guix, as well as how to install it and get
356 Note that this section is concerned with the installation of the package
357 manager, which can be done on top of a running GNU/Linux system. If,
358 instead, you want to install the complete GNU operating system,
359 @pxref{System Installation}.
361 @cindex foreign distro
362 When installed on a running GNU/Linux system---thereafter called a
363 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
364 without interference. Its data lives exclusively in two directories,
365 usually @file{/gnu/store} and @file{/var/guix}; other files on your
366 system, such as @file{/etc}, are left untouched.
368 Once installed, Guix can be updated by running @command{guix pull}
369 (@pxref{Invoking guix pull}).
372 * Binary Installation:: Getting Guix running in no time!
373 * Requirements:: Software needed to build and run Guix.
374 * Running the Test Suite:: Testing Guix.
375 * Setting Up the Daemon:: Preparing the build daemon's environment.
376 * Invoking guix-daemon:: Running the build daemon.
377 * Application Setup:: Application-specific setup.
380 @node Binary Installation
381 @section Binary Installation
383 @cindex installing Guix from binaries
384 This section describes how to install Guix on an arbitrary system from a
385 self-contained tarball providing binaries for Guix and for all its
386 dependencies. This is often quicker than installing from source, which
387 is described in the next sections. The only requirement is to have
390 Installing goes along these lines:
394 @cindex downloading Guix binary
395 Download the binary tarball from
396 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
397 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
398 already running the kernel Linux, and so on.
400 @c The following is somewhat duplicated in ``System Installation''.
401 Make sure to download the associated @file{.sig} file and to verify the
402 authenticity of the tarball against it, along these lines:
405 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
406 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
409 If that command fails because you do not have the required public key,
410 then run this command to import it:
413 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
417 and rerun the @code{gpg --verify} command.
418 @c end authentication part
425 # tar --warning=no-timestamp -xf \
426 guix-binary-@value{VERSION}.@var{system}.tar.xz
427 # mv var/guix /var/ && mv gnu /
430 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
431 The latter contains a ready-to-use profile for @code{root} (see next
434 Do @emph{not} unpack the tarball on a working Guix system since that
435 would overwrite its own essential files.
437 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
438 not emit warnings about ``implausibly old time stamps'' (such
439 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
441 They stem from the fact that all the
442 files in the archive have their modification time set to zero (which
443 means January 1st, 1970.) This is done on purpose to make sure the
444 archive content is independent of its creation time, thus making it
448 Make @code{root}'s profile available under @file{~/.guix-profile}:
451 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
455 Source @file{etc/profile} to augment @code{PATH} and other relevant
456 environment variables:
459 # GUIX_PROFILE=$HOME/.guix-profile \
460 source $GUIX_PROFILE/etc/profile
464 Create the group and user accounts for build users as explained below
465 (@pxref{Build Environment Setup}).
468 Run the daemon, and set it to automatically start on boot.
470 If your host distro uses the systemd init system, this can be achieved
473 @c Versions of systemd that supported symlinked service files are not
474 @c yet widely deployed, so we should suggest that users copy the service
477 @c See this thread for more information:
478 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
481 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
483 # systemctl start guix-daemon && systemctl enable guix-daemon
486 If your host distro uses the Upstart init system:
489 # initctl reload-configuration
490 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
494 Otherwise, you can still start the daemon manually with:
497 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
501 Make the @command{guix} command available to other users on the machine,
505 # mkdir -p /usr/local/bin
507 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
510 It is also a good idea to make the Info version of this manual available
514 # mkdir -p /usr/local/share/info
515 # cd /usr/local/share/info
516 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
520 That way, assuming @file{/usr/local/share/info} is in the search path,
521 running @command{info guix} will open this manual (@pxref{Other Info
522 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
526 @cindex substitutes, authorization thereof
527 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
528 (@pxref{Substitutes}), authorize them:
531 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
535 Each user may need to perform a few additional steps to make their Guix
536 environment ready for use, @pxref{Application Setup}.
539 Voilà, the installation is complete!
541 You can confirm that Guix is working by installing a sample package into
545 # guix package -i hello
548 The @code{guix} package must remain available in @code{root}'s profile,
549 or it would become subject to garbage collection---in which case you
550 would find yourself badly handicapped by the lack of the @command{guix}
551 command. In other words, do not remove @code{guix} by running
552 @code{guix package -r guix}.
554 The binary installation tarball can be (re)produced and verified simply
555 by running the following command in the Guix source tree:
558 make guix-binary.@var{system}.tar.xz
562 ... which, in turn, runs:
565 guix pack -s @var{system} --localstatedir guix
568 @xref{Invoking guix pack}, for more info on this handy tool.
571 @section Requirements
573 This section lists requirements when building Guix from source. The
574 build procedure for Guix is the same as for other GNU software, and is
575 not covered here. Please see the files @file{README} and @file{INSTALL}
576 in the Guix source tree for additional details.
578 GNU Guix depends on the following packages:
581 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
582 later, including 2.2.x;
583 @item @url{http://gnupg.org/, GNU libgcrypt};
585 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
586 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
587 Guile,, gnutls-guile, GnuTLS-Guile});
589 @c FIXME: Specify a version number once a release has been made.
590 @uref{https://gitlab.com/guile-git/guile-git, Guile-Git}, from August
592 @item @url{http://www.gnu.org/software/make/, GNU Make}.
595 The following dependencies are optional:
600 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
601 allow you to use the @command{guix import pypi} command (@pxref{Invoking
602 guix import}). It is of
603 interest primarily for developers and not for casual users.
606 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
607 Support for build offloading (@pxref{Daemon Offload Setup}) and
608 @command{guix copy} (@pxref{Invoking guix copy}) depends on
609 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
610 version 0.10.2 or later.
613 When @url{http://zlib.net, zlib} is available, @command{guix publish}
614 can compress build byproducts (@pxref{Invoking guix publish}).
617 Unless @code{--disable-daemon} was passed to @command{configure}, the
618 following packages are also needed:
621 @item @url{http://sqlite.org, SQLite 3};
622 @item @url{http://www.bzip.org, libbz2};
623 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
627 @cindex state directory
628 When configuring Guix on a system that already has a Guix installation,
629 be sure to specify the same state directory as the existing installation
630 using the @code{--localstatedir} option of the @command{configure}
631 script (@pxref{Directory Variables, @code{localstatedir},, standards,
632 GNU Coding Standards}). The @command{configure} script protects against
633 unintended misconfiguration of @var{localstatedir} so you do not
634 inadvertently corrupt your store (@pxref{The Store}).
636 @cindex Nix, compatibility
637 When a working installation of @url{http://nixos.org/nix/, the Nix package
638 manager} is available, you
639 can instead configure Guix with @code{--disable-daemon}. In that case,
640 Nix replaces the three dependencies above.
642 Guix is compatible with Nix, so it is possible to share the same store
643 between both. To do so, you must pass @command{configure} not only the
644 same @code{--with-store-dir} value, but also the same
645 @code{--localstatedir} value. The latter is essential because it
646 specifies where the database that stores metadata about the store is
647 located, among other things. The default values for Nix are
648 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
649 Note that @code{--disable-daemon} is not required if
650 your goal is to share the store with Nix.
652 @node Running the Test Suite
653 @section Running the Test Suite
656 After a successful @command{configure} and @code{make} run, it is a good
657 idea to run the test suite. It can help catch issues with the setup or
658 environment, or bugs in Guix itself---and really, reporting test
659 failures is a good way to help improve the software. To run the test
666 Test cases can run in parallel: you can use the @code{-j} option of
667 GNU@tie{}make to speed things up. The first run may take a few minutes
668 on a recent machine; subsequent runs will be faster because the store
669 that is created for test purposes will already have various things in
672 It is also possible to run a subset of the tests by defining the
673 @code{TESTS} makefile variable as in this example:
676 make check TESTS="tests/store.scm tests/cpio.scm"
679 By default, tests results are displayed at a file level. In order to
680 see the details of every individual test cases, it is possible to define
681 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
684 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
687 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
688 @file{test-suite.log} file. Please specify the Guix version being used
689 as well as version numbers of the dependencies (@pxref{Requirements}) in
692 Guix also comes with a whole-system test suite that tests complete
693 GuixSD operating system instances. It can only run on systems where
694 Guix is already installed, using:
701 or, again, by defining @code{TESTS} to select a subset of tests to run:
704 make check-system TESTS="basic mcron"
707 These system tests are defined in the @code{(gnu tests @dots{})}
708 modules. They work by running the operating systems under test with
709 lightweight instrumentation in a virtual machine (VM). They can be
710 computationally intensive or rather cheap, depending on whether
711 substitutes are available for their dependencies (@pxref{Substitutes}).
712 Some of them require a lot of storage space to hold VM images.
714 Again in case of test failures, please send @email{bug-guix@@gnu.org}
717 @node Setting Up the Daemon
718 @section Setting Up the Daemon
721 Operations such as building a package or running the garbage collector
722 are all performed by a specialized process, the @dfn{build daemon}, on
723 behalf of clients. Only the daemon may access the store and its
724 associated database. Thus, any operation that manipulates the store
725 goes through the daemon. For instance, command-line tools such as
726 @command{guix package} and @command{guix build} communicate with the
727 daemon (@i{via} remote procedure calls) to instruct it what to do.
729 The following sections explain how to prepare the build daemon's
730 environment. See also @ref{Substitutes}, for information on how to allow
731 the daemon to download pre-built binaries.
734 * Build Environment Setup:: Preparing the isolated build environment.
735 * Daemon Offload Setup:: Offloading builds to remote machines.
738 @node Build Environment Setup
739 @subsection Build Environment Setup
741 @cindex build environment
742 In a standard multi-user setup, Guix and its daemon---the
743 @command{guix-daemon} program---are installed by the system
744 administrator; @file{/gnu/store} is owned by @code{root} and
745 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
746 Guix tools to build packages or otherwise access the store, and the
747 daemon will do it on their behalf, ensuring that the store is kept in a
748 consistent state, and allowing built packages to be shared among users.
751 When @command{guix-daemon} runs as @code{root}, you may not want package
752 build processes themselves to run as @code{root} too, for obvious
753 security reasons. To avoid that, a special pool of @dfn{build users}
754 should be created for use by build processes started by the daemon.
755 These build users need not have a shell and a home directory: they will
756 just be used when the daemon drops @code{root} privileges in build
757 processes. Having several such users allows the daemon to launch
758 distinct build processes under separate UIDs, which guarantees that they
759 do not interfere with each other---an essential feature since builds are
760 regarded as pure functions (@pxref{Introduction}).
762 On a GNU/Linux system, a build user pool may be created like this (using
763 Bash syntax and the @code{shadow} commands):
765 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
766 @c for why `-G' is needed.
768 # groupadd --system guixbuild
769 # for i in `seq -w 1 10`;
771 useradd -g guixbuild -G guixbuild \
772 -d /var/empty -s `which nologin` \
773 -c "Guix build user $i" --system \
779 The number of build users determines how many build jobs may run in
780 parallel, as specified by the @option{--max-jobs} option
781 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
782 @command{guix system vm} and related commands, you may need to add the
783 build users to the @code{kvm} group so they can access @file{/dev/kvm},
784 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
785 (@pxref{Invoking guix system}).
787 The @code{guix-daemon} program may then be run as @code{root} with the
788 following command@footnote{If your machine uses the systemd init system,
789 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
790 file in @file{/etc/systemd/system} will ensure that
791 @command{guix-daemon} is automatically started. Similarly, if your
792 machine uses the Upstart init system, drop the
793 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
794 file in @file{/etc/init}.}:
797 # guix-daemon --build-users-group=guixbuild
802 This way, the daemon starts build processes in a chroot, under one of
803 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
804 environment contains nothing but:
806 @c Keep this list in sync with libstore/build.cc! -----------------------
809 a minimal @code{/dev} directory, created mostly independently from the
810 host @code{/dev}@footnote{``Mostly'', because while the set of files
811 that appear in the chroot's @code{/dev} is fixed, most of these files
812 can only be created if the host has them.};
815 the @code{/proc} directory; it only shows the processes of the container
816 since a separate PID name space is used;
819 @file{/etc/passwd} with an entry for the current user and an entry for
823 @file{/etc/group} with an entry for the user's group;
826 @file{/etc/hosts} with an entry that maps @code{localhost} to
830 a writable @file{/tmp} directory.
833 You can influence the directory where the daemon stores build trees
834 @i{via} the @code{TMPDIR} environment variable. However, the build tree
835 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
836 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
837 This way, the value of @code{TMPDIR} does not leak inside build
838 environments, which avoids discrepancies in cases where build processes
839 capture the name of their build tree.
842 The daemon also honors the @code{http_proxy} environment variable for
843 HTTP downloads it performs, be it for fixed-output derivations
844 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
846 If you are installing Guix as an unprivileged user, it is still possible
847 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
848 However, build processes will not be isolated from one another, and not
849 from the rest of the system. Thus, build processes may interfere with
850 each other, and may access programs, libraries, and other files
851 available on the system---making it much harder to view them as
852 @emph{pure} functions.
855 @node Daemon Offload Setup
856 @subsection Using the Offload Facility
860 When desired, the build daemon can @dfn{offload} derivation builds to
861 other machines running Guix, using the @code{offload} @dfn{build
862 hook}@footnote{This feature is available only when
863 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
865 feature is enabled, a list of user-specified build machines is read from
866 @file{/etc/guix/machines.scm}; every time a build is requested, for
867 instance via @code{guix build}, the daemon attempts to offload it to one
868 of the machines that satisfy the constraints of the derivation, in
869 particular its system type---e.g., @file{x86_64-linux}. Missing
870 prerequisites for the build are copied over SSH to the target machine,
871 which then proceeds with the build; upon success the output(s) of the
872 build are copied back to the initial machine.
874 The @file{/etc/guix/machines.scm} file typically looks like this:
878 (name "eightysix.example.org")
879 (system "x86_64-linux")
880 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
882 (speed 2.)) ;incredibly fast!
885 (name "meeps.example.org")
886 (system "mips64el-linux")
887 (host-key "ssh-rsa AAAAB3Nza@dots{}")
890 (string-append (getenv "HOME")
891 "/.ssh/identity-for-guix"))))
895 In the example above we specify a list of two build machines, one for
896 the @code{x86_64} architecture and one for the @code{mips64el}
899 In fact, this file is---not surprisingly!---a Scheme file that is
900 evaluated when the @code{offload} hook is started. Its return value
901 must be a list of @code{build-machine} objects. While this example
902 shows a fixed list of build machines, one could imagine, say, using
903 DNS-SD to return a list of potential build machines discovered in the
904 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
905 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
908 @deftp {Data Type} build-machine
909 This data type represents build machines to which the daemon may offload
910 builds. The important fields are:
915 The host name of the remote machine.
918 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
921 The user account to use when connecting to the remote machine over SSH.
922 Note that the SSH key pair must @emph{not} be passphrase-protected, to
923 allow non-interactive logins.
926 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
927 This is used to authenticate the machine when we connect to it. It is a
928 long string that looks like this:
931 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
934 If the machine is running the OpenSSH daemon, @command{sshd}, the host
935 key can be found in a file such as
936 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
938 If the machine is running the SSH daemon of GNU@tie{}lsh,
939 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
940 similar file. It can be converted to the OpenSSH format using
941 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
944 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
945 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
950 A number of optional fields may be specified:
954 @item @code{port} (default: @code{22})
955 Port number of SSH server on the machine.
957 @item @code{private-key} (default: @file{~root/.ssh/id_rsa})
958 The SSH private key file to use when connecting to the machine, in
961 Note that the default value is the private key @emph{of the root
962 account}. Make sure it exists if you use the default.
964 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
965 @itemx @code{compression-level} (default: @code{3})
966 The SSH-level compression methods and compression level requested.
968 Note that offloading relies on SSH compression to reduce bandwidth usage
969 when transferring files to and from build machines.
971 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
972 File name of the Unix-domain socket @command{guix-daemon} is listening
975 @item @code{parallel-builds} (default: @code{1})
976 The number of builds that may run in parallel on the machine.
978 @item @code{speed} (default: @code{1.0})
979 A ``relative speed factor''. The offload scheduler will tend to prefer
980 machines with a higher speed factor.
982 @item @code{features} (default: @code{'()})
983 A list of strings denoting specific features supported by the machine.
984 An example is @code{"kvm"} for machines that have the KVM Linux modules
985 and corresponding hardware support. Derivations can request features by
986 name, and they will be scheduled on matching build machines.
991 The @code{guile} command must be in the search path on the build
992 machines. In addition, the Guix modules must be in
993 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
994 this is the case by running:
997 ssh build-machine guile -c "'(use-modules (guix config))'"
1000 There is one last thing to do once @file{machines.scm} is in place. As
1001 explained above, when offloading, files are transferred back and forth
1002 between the machine stores. For this to work, you first need to
1003 generate a key pair on each machine to allow the daemon to export signed
1004 archives of files from the store (@pxref{Invoking guix archive}):
1007 # guix archive --generate-key
1011 Each build machine must authorize the key of the master machine so that
1012 it accepts store items it receives from the master:
1015 # guix archive --authorize < master-public-key.txt
1019 Likewise, the master machine must authorize the key of each build machine.
1021 All the fuss with keys is here to express pairwise mutual trust
1022 relations between the master and the build machines. Concretely, when
1023 the master receives files from a build machine (and @i{vice versa}), its
1024 build daemon can make sure they are genuine, have not been tampered
1025 with, and that they are signed by an authorized key.
1027 @cindex offload test
1028 To test whether your setup is operational, run this command on the
1035 This will attempt to connect to each of the build machines specified in
1036 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1037 available on each machine, attempt to export to the machine and import
1038 from it, and report any error in the process.
1040 If you want to test a different machine file, just specify it on the
1044 # guix offload test machines-qualif.scm
1047 Last, you can test the subset of the machines whose name matches a
1048 regular expression like this:
1051 # guix offload test machines.scm '\.gnu\.org$'
1054 @node Invoking guix-daemon
1055 @section Invoking @command{guix-daemon}
1057 The @command{guix-daemon} program implements all the functionality to
1058 access the store. This includes launching build processes, running the
1059 garbage collector, querying the availability of a build result, etc. It
1060 is normally run as @code{root} like this:
1063 # guix-daemon --build-users-group=guixbuild
1067 For details on how to set it up, @pxref{Setting Up the Daemon}.
1070 @cindex container, build environment
1071 @cindex build environment
1072 @cindex reproducible builds
1073 By default, @command{guix-daemon} launches build processes under
1074 different UIDs, taken from the build group specified with
1075 @code{--build-users-group}. In addition, each build process is run in a
1076 chroot environment that only contains the subset of the store that the
1077 build process depends on, as specified by its derivation
1078 (@pxref{Programming Interface, derivation}), plus a set of specific
1079 system directories. By default, the latter contains @file{/dev} and
1080 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1081 @dfn{container}: in addition to having its own file system tree, it has
1082 a separate mount name space, its own PID name space, network name space,
1083 etc. This helps achieve reproducible builds (@pxref{Features}).
1085 When the daemon performs a build on behalf of the user, it creates a
1086 build directory under @file{/tmp} or under the directory specified by
1087 its @code{TMPDIR} environment variable; this directory is shared with
1088 the container for the duration of the build. Be aware that using a
1089 directory other than @file{/tmp} can affect build results---for example,
1090 with a longer directory name, a build process that uses Unix-domain
1091 sockets might hit the name length limitation for @code{sun_path}, which
1092 it would otherwise not hit.
1094 The build directory is automatically deleted upon completion, unless the
1095 build failed and the client specified @option{--keep-failed}
1096 (@pxref{Invoking guix build, @option{--keep-failed}}).
1098 The following command-line options are supported:
1101 @item --build-users-group=@var{group}
1102 Take users from @var{group} to run build processes (@pxref{Setting Up
1103 the Daemon, build users}).
1105 @item --no-substitutes
1107 Do not use substitutes for build products. That is, always build things
1108 locally instead of allowing downloads of pre-built binaries
1109 (@pxref{Substitutes}).
1111 By default substitutes are used, unless the client---such as the
1112 @command{guix package} command---is explicitly invoked with
1113 @code{--no-substitutes}.
1115 When the daemon runs with @code{--no-substitutes}, clients can still
1116 explicitly enable substitution @i{via} the @code{set-build-options}
1117 remote procedure call (@pxref{The Store}).
1119 @item --substitute-urls=@var{urls}
1120 @anchor{daemon-substitute-urls}
1121 Consider @var{urls} the default whitespace-separated list of substitute
1122 source URLs. When this option is omitted,
1123 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1124 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1126 This means that substitutes may be downloaded from @var{urls}, as long
1127 as they are signed by a trusted signature (@pxref{Substitutes}).
1130 @item --no-build-hook
1131 Do not use the @dfn{build hook}.
1133 The build hook is a helper program that the daemon can start and to
1134 which it submits build requests. This mechanism is used to offload
1135 builds to other machines (@pxref{Daemon Offload Setup}).
1137 @item --cache-failures
1138 Cache build failures. By default, only successful builds are cached.
1140 When this option is used, @command{guix gc --list-failures} can be used
1141 to query the set of store items marked as failed; @command{guix gc
1142 --clear-failures} removes store items from the set of cached failures.
1143 @xref{Invoking guix gc}.
1145 @item --cores=@var{n}
1147 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1150 The default value is @code{0}, but it may be overridden by clients, such
1151 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1154 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1155 in the build process, which can then use it to exploit internal
1156 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1158 @item --max-jobs=@var{n}
1160 Allow at most @var{n} build jobs in parallel. The default value is
1161 @code{1}. Setting it to @code{0} means that no builds will be performed
1162 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1163 Setup}), or simply fail.
1165 @item --max-silent-time=@var{seconds}
1166 When the build or substitution process remains silent for more than
1167 @var{seconds}, terminate it and report a build failure.
1169 The default value is @code{0}, which disables the timeout.
1171 The value specified here can be overridden by clients (@pxref{Common
1172 Build Options, @code{--max-silent-time}}).
1174 @item --timeout=@var{seconds}
1175 Likewise, when the build or substitution process lasts for more than
1176 @var{seconds}, terminate it and report a build failure.
1178 The default value is @code{0}, which disables the timeout.
1180 The value specified here can be overridden by clients (@pxref{Common
1181 Build Options, @code{--timeout}}).
1183 @item --rounds=@var{N}
1184 Build each derivation @var{n} times in a row, and raise an error if
1185 consecutive build results are not bit-for-bit identical. Note that this
1186 setting can be overridden by clients such as @command{guix build}
1187 (@pxref{Invoking guix build}).
1189 When used in conjunction with @option{--keep-failed}, the differing
1190 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1191 This makes it easy to look for differences between the two results.
1194 Produce debugging output.
1196 This is useful to debug daemon start-up issues, but then it may be
1197 overridden by clients, for example the @code{--verbosity} option of
1198 @command{guix build} (@pxref{Invoking guix build}).
1200 @item --chroot-directory=@var{dir}
1201 Add @var{dir} to the build chroot.
1203 Doing this may change the result of build processes---for instance if
1204 they use optional dependencies found in @var{dir} when it is available,
1205 and not otherwise. For that reason, it is not recommended to do so.
1206 Instead, make sure that each derivation declares all the inputs that it
1209 @item --disable-chroot
1210 Disable chroot builds.
1212 Using this option is not recommended since, again, it would allow build
1213 processes to gain access to undeclared dependencies. It is necessary,
1214 though, when @command{guix-daemon} is running under an unprivileged user
1217 @item --disable-log-compression
1218 Disable compression of the build logs.
1220 Unless @code{--lose-logs} is used, all the build logs are kept in the
1221 @var{localstatedir}. To save space, the daemon automatically compresses
1222 them with bzip2 by default. This option disables that.
1224 @item --disable-deduplication
1225 @cindex deduplication
1226 Disable automatic file ``deduplication'' in the store.
1228 By default, files added to the store are automatically ``deduplicated'':
1229 if a newly added file is identical to another one found in the store,
1230 the daemon makes the new file a hard link to the other file. This can
1231 noticeably reduce disk usage, at the expense of slightly increased
1232 input/output load at the end of a build process. This option disables
1235 @item --gc-keep-outputs[=yes|no]
1236 Tell whether the garbage collector (GC) must keep outputs of live
1240 @cindex garbage collector roots
1241 When set to ``yes'', the GC will keep the outputs of any live derivation
1242 available in the store---the @code{.drv} files. The default is ``no'',
1243 meaning that derivation outputs are kept only if they are GC roots.
1244 @xref{Invoking guix gc}, for more on GC roots.
1246 @item --gc-keep-derivations[=yes|no]
1247 Tell whether the garbage collector (GC) must keep derivations
1248 corresponding to live outputs.
1250 When set to ``yes'', as is the case by default, the GC keeps
1251 derivations---i.e., @code{.drv} files---as long as at least one of their
1252 outputs is live. This allows users to keep track of the origins of
1253 items in their store. Setting it to ``no'' saves a bit of disk space.
1255 Note that when both @code{--gc-keep-derivations} and
1256 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1257 prerequisites (the sources, compiler, libraries, and other build-time
1258 tools) of live objects in the store, regardless of whether these
1259 prerequisites are live. This is convenient for developers since it
1260 saves rebuilds or downloads.
1262 @item --impersonate-linux-2.6
1263 On Linux-based systems, impersonate Linux 2.6. This means that the
1264 kernel's @code{uname} system call will report 2.6 as the release number.
1266 This might be helpful to build programs that (usually wrongfully) depend
1267 on the kernel version number.
1270 Do not keep build logs. By default they are kept under
1271 @code{@var{localstatedir}/guix/log}.
1273 @item --system=@var{system}
1274 Assume @var{system} as the current system type. By default it is the
1275 architecture/kernel pair found at configure time, such as
1276 @code{x86_64-linux}.
1278 @item --listen=@var{endpoint}
1279 Listen for connections on @var{endpoint}. @var{endpoint} is interpreted
1280 as the file name of a Unix-domain socket if it starts with
1281 @code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a
1282 host name or host name and port to listen to. Here are a few examples:
1285 @item --listen=/gnu/var/daemon
1286 Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket,
1287 creating it if needed.
1289 @item --listen=localhost
1290 @cindex daemon, remote access
1291 @cindex remote access to the daemon
1292 @cindex daemon, cluster setup
1293 @cindex clusters, daemon setup
1294 Listen for TCP connections on the network interface corresponding to
1295 @code{localhost}, on port 44146.
1297 @item --listen=128.0.0.42:1234
1298 Listen for TCP connections on the network interface corresponding to
1299 @code{128.0.0.42}, on port 1234.
1302 This option can be repeated multiple times, in which case
1303 @command{guix-daemon} accepts connections on all the specified
1304 endpoints. Users can tell client commands what endpoint to connect to
1305 by setting the @code{GUIX_DAEMON_SOCKET} environment variable
1306 (@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}).
1309 The daemon protocol is @emph{unauthenticated and unencrypted}. Using
1310 @code{--listen=@var{host}} is suitable on local networks, such as
1311 clusters, where only trusted nodes may connect to the build daemon. In
1312 other cases where remote access to the daemon is needed, we recommend
1313 using Unix-domain sockets along with SSH.
1316 When @code{--listen} is omitted, @command{guix-daemon} listens for
1317 connections on the Unix-domain socket located at
1318 @file{@var{localstatedir}/daemon-socket/socket}.
1322 @node Application Setup
1323 @section Application Setup
1325 @cindex foreign distro
1326 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1327 so-called @dfn{foreign distro}---a few additional steps are needed to
1328 get everything in place. Here are some of them.
1332 @anchor{locales-and-locpath}
1333 @cindex locales, when not on GuixSD
1335 @vindex GUIX_LOCPATH
1336 Packages installed @i{via} Guix will not use the locale data of the
1337 host system. Instead, you must first install one of the locale packages
1338 available with Guix and then define the @code{GUIX_LOCPATH} environment
1342 $ guix package -i glibc-locales
1343 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1346 Note that the @code{glibc-locales} package contains data for all the
1347 locales supported by the GNU@tie{}libc and weighs in at around
1348 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1349 limited to a few UTF-8 locales.
1351 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1352 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1353 Manual}). There are two important differences though:
1357 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1358 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1359 to make sure the programs of the foreign distro will not end up loading
1360 incompatible locale data.
1363 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1364 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1365 should your Guix profile contain a mixture of programs linked against
1366 different libc version, each libc version will only try to load locale
1367 data in the right format.
1370 This is important because the locale data format used by different libc
1371 versions may be incompatible.
1373 @subsection Name Service Switch
1375 @cindex name service switch, glibc
1376 @cindex NSS (name service switch), glibc
1377 @cindex nscd (name service caching daemon)
1378 @cindex name service caching daemon (nscd)
1379 When using Guix on a foreign distro, we @emph{strongly recommend} that
1380 the system run the GNU C library's @dfn{name service cache daemon},
1381 @command{nscd}, which should be listening on the
1382 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1383 installed with Guix may fail to look up host names or user accounts, or
1384 may even crash. The next paragraphs explain why.
1386 @cindex @file{nsswitch.conf}
1387 The GNU C library implements a @dfn{name service switch} (NSS), which is
1388 an extensible mechanism for ``name lookups'' in general: host name
1389 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1390 The GNU C Library Reference Manual}).
1392 @cindex Network information service (NIS)
1393 @cindex NIS (Network information service)
1394 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1395 lookup implementations: for example, the @code{nss-mdns} plugin allow
1396 resolution of @code{.local} host names, the @code{nis} plugin allows
1397 user account lookup using the Network information service (NIS), and so
1398 on. These extra ``lookup services'' are configured system-wide in
1399 @file{/etc/nsswitch.conf}, and all the programs running on the system
1400 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1403 When they perform a name lookup---for instance by calling the
1404 @code{getaddrinfo} function in C---applications first try to connect to
1405 the nscd; on success, nscd performs name lookups on their behalf. If
1406 the nscd is not running, then they perform the name lookup by
1407 themselves, by loading the name lookup services into their own address
1408 space and running it. These name lookup services---the
1409 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1410 the host system's C library, rather than from the C library the
1411 application is linked against (the C library coming from Guix).
1413 And this is where the problem is: if your application is linked against
1414 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1415 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1416 likely crash or have its name lookups fail unexpectedly.
1418 Running @command{nscd} on the system, among other advantages, eliminates
1419 this binary incompatibility problem because those @code{libnss_*.so}
1420 files are loaded in the @command{nscd} process, not in applications
1423 @subsection X11 Fonts
1426 The majority of graphical applications use Fontconfig to locate and
1427 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1428 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1429 by default. Thus, to allow graphical applications installed with Guix
1430 to display fonts, you have to install fonts with Guix as well.
1431 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1432 @code{font-gnu-freefont-ttf}.
1434 To display text written in Chinese languages, Japanese, or Korean in
1435 graphical applications, consider installing
1436 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1437 has multiple outputs, one per language family (@pxref{Packages with
1438 Multiple Outputs}). For instance, the following command installs fonts
1439 for Chinese languages:
1442 guix package -i font-adobe-source-han-sans:cn
1445 @cindex @code{xterm}
1446 Older programs such as @command{xterm} do not use Fontconfig and instead
1447 rely on server-side font rendering. Such programs require to specify a
1448 full name of a font using XLFD (X Logical Font Description), like this:
1451 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1454 To be able to use such full names for the TrueType fonts installed in
1455 your Guix profile, you need to extend the font path of the X server:
1458 xset +fp ~/.guix-profile/share/fonts/truetype
1461 @cindex @code{xlsfonts}
1462 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1463 to make sure your TrueType fonts are listed there.
1465 @cindex @code{fc-cache}
1467 After installing fonts you may have to refresh the font cache to use
1468 them in applications. The same applies when applications installed via
1469 Guix do not seem to find fonts. To force rebuilding of the font cache
1470 run @code{fc-cache -f}. The @code{fc-cache} command is provided by the
1471 @code{fontconfig} package.
1473 @subsection X.509 Certificates
1475 @cindex @code{nss-certs}
1476 The @code{nss-certs} package provides X.509 certificates, which allow
1477 programs to authenticate Web servers accessed over HTTPS.
1479 When using Guix on a foreign distro, you can install this package and
1480 define the relevant environment variables so that packages know where to
1481 look for certificates. @xref{X.509 Certificates}, for detailed
1484 @subsection Emacs Packages
1486 @cindex @code{emacs}
1487 When you install Emacs packages with Guix, the elisp files may be placed
1488 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1490 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1491 directory exists because potentially there may exist thousands of Emacs
1492 packages and storing all their files in a single directory may be not
1493 reliable (because of name conflicts). So we think using a separate
1494 directory for each package is a good idea. It is very similar to how
1495 the Emacs package system organizes the file structure (@pxref{Package
1496 Files,,, emacs, The GNU Emacs Manual}).
1498 By default, Emacs (installed with Guix) ``knows'' where these packages
1499 are placed, so you do not need to perform any configuration. If, for
1500 some reason, you want to avoid auto-loading Emacs packages installed
1501 with Guix, you can do so by running Emacs with @code{--no-site-file}
1502 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1504 @subsection The GCC toolchain
1509 Guix offers individual compiler packages such as @code{gcc} but if you
1510 are in need of a complete toolchain for compiling and linking source
1511 code what you really want is the @code{gcc-toolchain} package. This
1512 package provides a complete GCC toolchain for C/C++ development,
1513 including GCC itself, the GNU C Library (headers and binaries, plus
1514 debugging symbols in the @code{debug} output), Binutils, and a linker
1517 @cindex attempt to use impure library, error message
1519 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1520 passed to the linker, add corresponding @code{-rpath} arguments, and
1521 invoke the actual linker with this new set of arguments. By default,
1522 the linker wrapper refuses to link to libraries outside the store to
1523 ensure ``purity''. This can be annoying when using the toolchain to
1524 link with local libraries. To allow references to libraries outside the
1525 store you need to define the environment variable
1526 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1530 @c *********************************************************************
1531 @node Package Management
1532 @chapter Package Management
1535 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1536 remove software packages, without having to know about their build
1537 procedures or dependencies. Guix also goes beyond this obvious set of
1540 This chapter describes the main features of Guix, as well as the
1541 package management tools it provides. Along with the command-line
1542 interface described below (@pxref{Invoking guix package, @code{guix
1543 package}}), you may also use Emacs Interface (@pxref{Top,,,
1544 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1545 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1549 guix package -i emacs-guix
1553 * Features:: How Guix will make your life brighter.
1554 * Invoking guix package:: Package installation, removal, etc.
1555 * Substitutes:: Downloading pre-built binaries.
1556 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1557 * Invoking guix gc:: Running the garbage collector.
1558 * Invoking guix pull:: Fetching the latest Guix and distribution.
1559 * Invoking guix pack:: Creating software bundles.
1560 * Invoking guix archive:: Exporting and importing store files.
1566 When using Guix, each package ends up in the @dfn{package store}, in its
1567 own directory---something that resembles
1568 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1570 Instead of referring to these directories, users have their own
1571 @dfn{profile}, which points to the packages that they actually want to
1572 use. These profiles are stored within each user's home directory, at
1573 @code{$HOME/.guix-profile}.
1575 For example, @code{alice} installs GCC 4.7.2. As a result,
1576 @file{/home/alice/.guix-profile/bin/gcc} points to
1577 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1578 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1579 simply continues to point to
1580 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1581 coexist on the same system without any interference.
1583 The @command{guix package} command is the central tool to manage
1584 packages (@pxref{Invoking guix package}). It operates on the per-user
1585 profiles, and can be used @emph{with normal user privileges}.
1587 @cindex transactions
1588 The command provides the obvious install, remove, and upgrade
1589 operations. Each invocation is actually a @emph{transaction}: either
1590 the specified operation succeeds, or nothing happens. Thus, if the
1591 @command{guix package} process is terminated during the transaction,
1592 or if a power outage occurs during the transaction, then the user's
1593 profile remains in its previous state, and remains usable.
1595 In addition, any package transaction may be @emph{rolled back}. So, if,
1596 for example, an upgrade installs a new version of a package that turns
1597 out to have a serious bug, users may roll back to the previous instance
1598 of their profile, which was known to work well. Similarly, the global
1599 system configuration on GuixSD is subject to
1600 transactional upgrades and roll-back
1601 (@pxref{Using the Configuration System}).
1603 All packages in the package store may be @emph{garbage-collected}.
1604 Guix can determine which packages are still referenced by user
1605 profiles, and remove those that are provably no longer referenced
1606 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1607 generations of their profile so that the packages they refer to can be
1610 @cindex reproducibility
1611 @cindex reproducible builds
1612 Finally, Guix takes a @dfn{purely functional} approach to package
1613 management, as described in the introduction (@pxref{Introduction}).
1614 Each @file{/gnu/store} package directory name contains a hash of all the
1615 inputs that were used to build that package---compiler, libraries, build
1616 scripts, etc. This direct correspondence allows users to make sure a
1617 given package installation matches the current state of their
1618 distribution. It also helps maximize @dfn{build reproducibility}:
1619 thanks to the isolated build environments that are used, a given build
1620 is likely to yield bit-identical files when performed on different
1621 machines (@pxref{Invoking guix-daemon, container}).
1624 This foundation allows Guix to support @dfn{transparent binary/source
1625 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1626 available from an external source---a @dfn{substitute}, Guix just
1627 downloads it and unpacks it;
1628 otherwise, it builds the package from source, locally
1629 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1630 reproducible, users do not have to trust servers that provide
1631 substitutes: they can force a local build and @emph{challenge} providers
1632 (@pxref{Invoking guix challenge}).
1634 Control over the build environment is a feature that is also useful for
1635 developers. The @command{guix environment} command allows developers of
1636 a package to quickly set up the right development environment for their
1637 package, without having to manually install the dependencies of the
1638 package into their profile (@pxref{Invoking guix environment}).
1640 @node Invoking guix package
1641 @section Invoking @command{guix package}
1643 @cindex installing packages
1644 @cindex removing packages
1645 @cindex package installation
1646 @cindex package removal
1647 The @command{guix package} command is the tool that allows users to
1648 install, upgrade, and remove packages, as well as rolling back to
1649 previous configurations. It operates only on the user's own profile,
1650 and works with normal user privileges (@pxref{Features}). Its syntax
1654 guix package @var{options}
1656 @cindex transactions
1657 Primarily, @var{options} specifies the operations to be performed during
1658 the transaction. Upon completion, a new profile is created, but
1659 previous @dfn{generations} of the profile remain available, should the user
1662 For example, to remove @code{lua} and install @code{guile} and
1663 @code{guile-cairo} in a single transaction:
1666 guix package -r lua -i guile guile-cairo
1669 @command{guix package} also supports a @dfn{declarative approach}
1670 whereby the user specifies the exact set of packages to be available and
1671 passes it @i{via} the @option{--manifest} option
1672 (@pxref{profile-manifest, @option{--manifest}}).
1675 For each user, a symlink to the user's default profile is automatically
1676 created in @file{$HOME/.guix-profile}. This symlink always points to the
1677 current generation of the user's default profile. Thus, users can add
1678 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1679 variable, and so on.
1680 @cindex search paths
1681 If you are not using the Guix System Distribution, consider adding the
1682 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1683 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1684 shells get all the right environment variable definitions:
1687 GUIX_PROFILE="$HOME/.guix-profile" \
1688 source "$HOME/.guix-profile/etc/profile"
1691 In a multi-user setup, user profiles are stored in a place registered as
1692 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1693 to (@pxref{Invoking guix gc}). That directory is normally
1694 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1695 @var{localstatedir} is the value passed to @code{configure} as
1696 @code{--localstatedir}, and @var{user} is the user name. The
1697 @file{per-user} directory is created when @command{guix-daemon} is
1698 started, and the @var{user} sub-directory is created by @command{guix
1701 The @var{options} can be among the following:
1705 @item --install=@var{package} @dots{}
1706 @itemx -i @var{package} @dots{}
1707 Install the specified @var{package}s.
1709 Each @var{package} may specify either a simple package name, such as
1710 @code{guile}, or a package name followed by an at-sign and version number,
1711 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1712 case, the newest version prefixed by @code{1.8} is selected.)
1714 If no version number is specified, the
1715 newest available version will be selected. In addition, @var{package}
1716 may contain a colon, followed by the name of one of the outputs of the
1717 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1718 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1719 name (and optionally version) are searched for among the GNU
1720 distribution modules (@pxref{Package Modules}).
1722 @cindex propagated inputs
1723 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1724 that automatically get installed along with the required package
1725 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1726 @code{package} objects}, for information about propagated inputs in
1727 package definitions).
1729 @anchor{package-cmd-propagated-inputs}
1730 An example is the GNU MPC library: its C header files refer to those of
1731 the GNU MPFR library, which in turn refer to those of the GMP library.
1732 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1733 in the profile; removing MPC also removes MPFR and GMP---unless they had
1734 also been explicitly installed by the user.
1736 Besides, packages sometimes rely on the definition of environment
1737 variables for their search paths (see explanation of
1738 @code{--search-paths} below). Any missing or possibly incorrect
1739 environment variable definitions are reported here.
1741 @item --install-from-expression=@var{exp}
1743 Install the package @var{exp} evaluates to.
1745 @var{exp} must be a Scheme expression that evaluates to a
1746 @code{<package>} object. This option is notably useful to disambiguate
1747 between same-named variants of a package, with expressions such as
1748 @code{(@@ (gnu packages base) guile-final)}.
1750 Note that this option installs the first output of the specified
1751 package, which may be insufficient when needing a specific output of a
1752 multiple-output package.
1754 @item --install-from-file=@var{file}
1755 @itemx -f @var{file}
1756 Install the package that the code within @var{file} evaluates to.
1758 As an example, @var{file} might contain a definition like this
1759 (@pxref{Defining Packages}):
1762 @verbatiminclude package-hello.scm
1765 Developers may find it useful to include such a @file{guix.scm} file
1766 in the root of their project source tree that can be used to test
1767 development snapshots and create reproducible development environments
1768 (@pxref{Invoking guix environment}).
1770 @item --remove=@var{package} @dots{}
1771 @itemx -r @var{package} @dots{}
1772 Remove the specified @var{package}s.
1774 As for @code{--install}, each @var{package} may specify a version number
1775 and/or output name in addition to the package name. For instance,
1776 @code{-r glibc:debug} would remove the @code{debug} output of
1779 @item --upgrade[=@var{regexp} @dots{}]
1780 @itemx -u [@var{regexp} @dots{}]
1781 @cindex upgrading packages
1782 Upgrade all the installed packages. If one or more @var{regexp}s are
1783 specified, upgrade only installed packages whose name matches a
1784 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1786 Note that this upgrades package to the latest version of packages found
1787 in the distribution currently installed. To update your distribution,
1788 you should regularly run @command{guix pull} (@pxref{Invoking guix
1791 @item --do-not-upgrade[=@var{regexp} @dots{}]
1792 When used together with the @code{--upgrade} option, do @emph{not}
1793 upgrade any packages whose name matches a @var{regexp}. For example, to
1794 upgrade all packages in the current profile except those containing the
1795 substring ``emacs'':
1798 $ guix package --upgrade . --do-not-upgrade emacs
1801 @item @anchor{profile-manifest}--manifest=@var{file}
1802 @itemx -m @var{file}
1803 @cindex profile declaration
1804 @cindex profile manifest
1805 Create a new generation of the profile from the manifest object
1806 returned by the Scheme code in @var{file}.
1808 This allows you to @emph{declare} the profile's contents rather than
1809 constructing it through a sequence of @code{--install} and similar
1810 commands. The advantage is that @var{file} can be put under version
1811 control, copied to different machines to reproduce the same profile, and
1814 @c FIXME: Add reference to (guix profile) documentation when available.
1815 @var{file} must return a @dfn{manifest} object, which is roughly a list
1818 @findex packages->manifest
1820 (use-package-modules guile emacs)
1825 ;; Use a specific package output.
1826 (list guile-2.0 "debug")))
1829 @findex specifications->manifest
1830 In this example we have to know which modules define the @code{emacs}
1831 and @code{guile-2.0} variables to provide the right
1832 @code{use-package-modules} line, which can be cumbersome. We can
1833 instead provide regular package specifications and let
1834 @code{specifications->manifest} look up the corresponding package
1838 (specifications->manifest
1839 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1843 @cindex rolling back
1844 @cindex undoing transactions
1845 @cindex transactions, undoing
1846 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1847 the last transaction.
1849 When combined with options such as @code{--install}, roll back occurs
1850 before any other actions.
1852 When rolling back from the first generation that actually contains
1853 installed packages, the profile is made to point to the @dfn{zeroth
1854 generation}, which contains no files apart from its own metadata.
1856 After having rolled back, installing, removing, or upgrading packages
1857 overwrites previous future generations. Thus, the history of the
1858 generations in a profile is always linear.
1860 @item --switch-generation=@var{pattern}
1861 @itemx -S @var{pattern}
1863 Switch to a particular generation defined by @var{pattern}.
1865 @var{pattern} may be either a generation number or a number prefixed
1866 with ``+'' or ``-''. The latter means: move forward/backward by a
1867 specified number of generations. For example, if you want to return to
1868 the latest generation after @code{--roll-back}, use
1869 @code{--switch-generation=+1}.
1871 The difference between @code{--roll-back} and
1872 @code{--switch-generation=-1} is that @code{--switch-generation} will
1873 not make a zeroth generation, so if a specified generation does not
1874 exist, the current generation will not be changed.
1876 @item --search-paths[=@var{kind}]
1877 @cindex search paths
1878 Report environment variable definitions, in Bash syntax, that may be
1879 needed in order to use the set of installed packages. These environment
1880 variables are used to specify @dfn{search paths} for files used by some
1881 of the installed packages.
1883 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1884 environment variables to be defined so it can look for headers and
1885 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1886 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1887 library are installed in the profile, then @code{--search-paths} will
1888 suggest setting these variables to @code{@var{profile}/include} and
1889 @code{@var{profile}/lib}, respectively.
1891 The typical use case is to define these environment variables in the
1895 $ eval `guix package --search-paths`
1898 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1899 meaning that the returned environment variable definitions will either
1900 be exact settings, or prefixes or suffixes of the current value of these
1901 variables. When omitted, @var{kind} defaults to @code{exact}.
1903 This option can also be used to compute the @emph{combined} search paths
1904 of several profiles. Consider this example:
1907 $ guix package -p foo -i guile
1908 $ guix package -p bar -i guile-json
1909 $ guix package -p foo -p bar --search-paths
1912 The last command above reports about the @code{GUILE_LOAD_PATH}
1913 variable, even though, taken individually, neither @file{foo} nor
1914 @file{bar} would lead to that recommendation.
1917 @item --profile=@var{profile}
1918 @itemx -p @var{profile}
1919 Use @var{profile} instead of the user's default profile.
1922 Produce verbose output. In particular, emit the build log of the
1923 environment on the standard error port.
1926 Use the bootstrap Guile to build the profile. This option is only
1927 useful to distribution developers.
1931 In addition to these actions, @command{guix package} supports the
1932 following options to query the current state of a profile, or the
1933 availability of packages:
1937 @item --search=@var{regexp}
1938 @itemx -s @var{regexp}
1939 @cindex searching for packages
1940 List the available packages whose name, synopsis, or description matches
1941 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1942 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1943 GNU recutils manual}).
1945 This allows specific fields to be extracted using the @command{recsel}
1946 command, for instance:
1949 $ guix package -s malloc | recsel -p name,version,relevance
1963 Similarly, to show the name of all the packages available under the
1964 terms of the GNU@tie{}LGPL version 3:
1967 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1974 It is also possible to refine search results using several @code{-s}
1975 flags. For example, the following command returns a list of board
1979 $ guix package -s '\<board\>' -s game | recsel -p name
1984 If we were to omit @code{-s game}, we would also get software packages
1985 that deal with printed circuit boards; removing the angle brackets
1986 around @code{board} would further add packages that have to do with
1989 And now for a more elaborate example. The following command searches
1990 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1991 libraries, and prints the name and synopsis of the matching packages:
1994 $ guix package -s crypto -s library | \
1995 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1999 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
2000 information on @dfn{selection expressions} for @code{recsel -e}.
2002 @item --show=@var{package}
2003 Show details about @var{package}, taken from the list of available packages, in
2004 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
2008 $ guix package --show=python | recsel -p name,version
2016 You may also specify the full name of a package to only get details about a
2017 specific version of it:
2019 $ guix package --show=python@@3.4 | recsel -p name,version
2026 @item --list-installed[=@var{regexp}]
2027 @itemx -I [@var{regexp}]
2028 List the currently installed packages in the specified profile, with the
2029 most recently installed packages shown last. When @var{regexp} is
2030 specified, list only installed packages whose name matches @var{regexp}.
2032 For each installed package, print the following items, separated by
2033 tabs: the package name, its version string, the part of the package that
2034 is installed (for instance, @code{out} for the default output,
2035 @code{include} for its headers, etc.), and the path of this package in
2038 @item --list-available[=@var{regexp}]
2039 @itemx -A [@var{regexp}]
2040 List packages currently available in the distribution for this system
2041 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
2042 installed packages whose name matches @var{regexp}.
2044 For each package, print the following items separated by tabs: its name,
2045 its version string, the parts of the package (@pxref{Packages with
2046 Multiple Outputs}), and the source location of its definition.
2048 @item --list-generations[=@var{pattern}]
2049 @itemx -l [@var{pattern}]
2051 Return a list of generations along with their creation dates; for each
2052 generation, show the installed packages, with the most recently
2053 installed packages shown last. Note that the zeroth generation is never
2056 For each installed package, print the following items, separated by
2057 tabs: the name of a package, its version string, the part of the package
2058 that is installed (@pxref{Packages with Multiple Outputs}), and the
2059 location of this package in the store.
2061 When @var{pattern} is used, the command returns only matching
2062 generations. Valid patterns include:
2065 @item @emph{Integers and comma-separated integers}. Both patterns denote
2066 generation numbers. For instance, @code{--list-generations=1} returns
2069 And @code{--list-generations=1,8,2} outputs three generations in the
2070 specified order. Neither spaces nor trailing commas are allowed.
2072 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2073 specified generations and everything in between. Note that the start of
2074 a range must be smaller than its end.
2076 It is also possible to omit the endpoint. For example,
2077 @code{--list-generations=2..}, returns all generations starting from the
2080 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2081 or months by passing an integer along with the first letter of the
2082 duration. For example, @code{--list-generations=20d} lists generations
2083 that are up to 20 days old.
2086 @item --delete-generations[=@var{pattern}]
2087 @itemx -d [@var{pattern}]
2088 When @var{pattern} is omitted, delete all generations except the current
2091 This command accepts the same patterns as @option{--list-generations}.
2092 When @var{pattern} is specified, delete the matching generations. When
2093 @var{pattern} specifies a duration, generations @emph{older} than the
2094 specified duration match. For instance, @code{--delete-generations=1m}
2095 deletes generations that are more than one month old.
2097 If the current generation matches, it is @emph{not} deleted. Also, the
2098 zeroth generation is never deleted.
2100 Note that deleting generations prevents rolling back to them.
2101 Consequently, this command must be used with care.
2105 Finally, since @command{guix package} may actually start build
2106 processes, it supports all the common build options (@pxref{Common Build
2107 Options}). It also supports package transformation options, such as
2108 @option{--with-source} (@pxref{Package Transformation Options}).
2109 However, note that package transformations are lost when upgrading; to
2110 preserve transformations across upgrades, you should define your own
2111 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2112 (@pxref{Defining Packages}).
2116 @section Substitutes
2119 @cindex pre-built binaries
2120 Guix supports transparent source/binary deployment, which means that it
2121 can either build things locally, or download pre-built items from a
2122 server. We call these pre-built items @dfn{substitutes}---they are
2123 substitutes for local build results. In many cases, downloading a
2124 substitute is much faster than building things locally.
2126 Substitutes can be anything resulting from a derivation build
2127 (@pxref{Derivations}). Of course, in the common case, they are
2128 pre-built package binaries, but source tarballs, for instance, which
2129 also result from derivation builds, can be available as substitutes.
2131 The @code{hydra.gnu.org} server is a front-end to a build farm that
2132 builds packages from the GNU distribution continuously for some
2133 architectures, and makes them available as substitutes. This is the
2134 default source of substitutes; it can be overridden by passing the
2135 @option{--substitute-urls} option either to @command{guix-daemon}
2136 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2137 or to client tools such as @command{guix package}
2138 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2141 Substitute URLs can be either HTTP or HTTPS.
2142 HTTPS is recommended because communications are encrypted; conversely,
2143 using HTTP makes all communications visible to an eavesdropper, who
2144 could use the information gathered to determine, for instance, whether
2145 your system has unpatched security vulnerabilities.
2148 @cindex digital signatures
2149 @cindex substitutes, authorization thereof
2150 @cindex access control list (ACL), for substitutes
2151 @cindex ACL (access control list), for substitutes
2152 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2154 must add its public key to the access control list (ACL) of archive
2155 imports, using the @command{guix archive} command (@pxref{Invoking guix
2156 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2157 be compromised and to serve genuine substitutes.
2159 This public key is installed along with Guix, in
2160 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2161 the installation prefix of Guix. If you installed Guix from source,
2162 make sure you checked the GPG signature of
2163 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2164 Then, you can run something like this:
2167 # guix archive --authorize < hydra.gnu.org.pub
2170 Once this is in place, the output of a command like @code{guix build}
2171 should change from something like:
2174 $ guix build emacs --dry-run
2175 The following derivations would be built:
2176 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2177 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2178 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2179 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2187 $ guix build emacs --dry-run
2188 The following files would be downloaded:
2189 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2190 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2191 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2192 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2197 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2198 will be downloaded, when possible, for future builds.
2200 Guix detects and raises an error when attempting to use a substitute
2201 that has been tampered with. Likewise, it ignores substitutes that are
2202 not signed, or that are not signed by one of the keys listed in the ACL.
2204 There is one exception though: if an unauthorized server provides
2205 substitutes that are @emph{bit-for-bit identical} to those provided by
2206 an authorized server, then the unauthorized server becomes eligible for
2207 downloads. For example, assume we have chosen two substitute servers
2211 --substitute-urls="https://a.example.org https://b.example.org"
2215 @cindex reproducible builds
2216 If the ACL contains only the key for @code{b.example.org}, and if
2217 @code{a.example.org} happens to serve the @emph{exact same} substitutes,
2218 then Guix will download substitutes from @code{a.example.org} because it
2219 comes first in the list and can be considered a mirror of
2220 @code{b.example.org}. In practice, independent build machines usually
2221 produce the same binaries, thanks to bit-reproducible builds (see
2225 Substitutes are downloaded over HTTP or HTTPS.
2226 The @code{http_proxy} environment
2227 variable can be set in the environment of @command{guix-daemon} and is
2228 honored for downloads of substitutes. Note that the value of
2229 @code{http_proxy} in the environment where @command{guix build},
2230 @command{guix package}, and other client commands are run has
2231 @emph{absolutely no effect}.
2233 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2234 (in other words, the server is not authenticated), contrary to what
2235 HTTPS clients such as Web browsers usually do. This is because Guix
2236 authenticates substitute information itself, as explained above, which
2237 is what we care about (whereas X.509 certificates are about
2238 authenticating bindings between domain names and public keys.)
2240 You can get statistics on the substitutes provided by a server using the
2241 @command{guix weather} command (@pxref{Invoking guix weather}).
2243 The substitute mechanism can be disabled globally by running
2244 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2245 guix-daemon}). It can also be disabled temporarily by passing the
2246 @code{--no-substitutes} option to @command{guix package}, @command{guix
2247 build}, and other command-line tools.
2250 @unnumberedsubsec On Trusting Binaries
2252 Today, each individual's control over their own computing is at the
2253 mercy of institutions, corporations, and groups with enough power and
2254 determination to subvert the computing infrastructure and exploit its
2255 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2256 convenient, we encourage users to also build on their own, or even run
2257 their own build farm, such that @code{hydra.gnu.org} is less of an
2258 interesting target. One way to help is by publishing the software you
2259 build using @command{guix publish} so that others have one more choice
2260 of server to download substitutes from (@pxref{Invoking guix publish}).
2262 Guix has the foundations to maximize build reproducibility
2263 (@pxref{Features}). In most cases, independent builds of a given
2264 package or derivation should yield bit-identical results. Thus, through
2265 a diverse set of independent package builds, we can strengthen the
2266 integrity of our systems. The @command{guix challenge} command aims to
2267 help users assess substitute servers, and to assist developers in
2268 finding out about non-deterministic package builds (@pxref{Invoking guix
2269 challenge}). Similarly, the @option{--check} option of @command{guix
2270 build} allows users to check whether previously-installed substitutes
2271 are genuine by rebuilding them locally (@pxref{build-check,
2272 @command{guix build --check}}).
2274 In the future, we want Guix to have support to publish and retrieve
2275 binaries to/from other users, in a peer-to-peer fashion. If you would
2276 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2279 @node Packages with Multiple Outputs
2280 @section Packages with Multiple Outputs
2282 @cindex multiple-output packages
2283 @cindex package outputs
2286 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2287 source package leads to exactly one directory in the store. When running
2288 @command{guix package -i glibc}, one installs the default output of the
2289 GNU libc package; the default output is called @code{out}, but its name
2290 can be omitted as shown in this command. In this particular case, the
2291 default output of @code{glibc} contains all the C header files, shared
2292 libraries, static libraries, Info documentation, and other supporting
2295 Sometimes it is more appropriate to separate the various types of files
2296 produced from a single source package into separate outputs. For
2297 instance, the GLib C library (used by GTK+ and related packages)
2298 installs more than 20 MiB of reference documentation as HTML pages.
2299 To save space for users who do not need it, the documentation goes to a
2300 separate output, called @code{doc}. To install the main GLib output,
2301 which contains everything but the documentation, one would run:
2304 guix package -i glib
2307 @cindex documentation
2308 The command to install its documentation is:
2311 guix package -i glib:doc
2314 Some packages install programs with different ``dependency footprints''.
2315 For instance, the WordNet package installs both command-line tools and
2316 graphical user interfaces (GUIs). The former depend solely on the C
2317 library, whereas the latter depend on Tcl/Tk and the underlying X
2318 libraries. In this case, we leave the command-line tools in the default
2319 output, whereas the GUIs are in a separate output. This allows users
2320 who do not need the GUIs to save space. The @command{guix size} command
2321 can help find out about such situations (@pxref{Invoking guix size}).
2322 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2324 There are several such multiple-output packages in the GNU distribution.
2325 Other conventional output names include @code{lib} for libraries and
2326 possibly header files, @code{bin} for stand-alone programs, and
2327 @code{debug} for debugging information (@pxref{Installing Debugging
2328 Files}). The outputs of a packages are listed in the third column of
2329 the output of @command{guix package --list-available} (@pxref{Invoking
2333 @node Invoking guix gc
2334 @section Invoking @command{guix gc}
2336 @cindex garbage collector
2338 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2339 The @command{guix gc} command allows users to explicitly run the garbage
2340 collector to reclaim space from the @file{/gnu/store} directory. It is
2341 the @emph{only} way to remove files from @file{/gnu/store}---removing
2342 files or directories manually may break it beyond repair!
2345 @cindex garbage collector roots
2346 The garbage collector has a set of known @dfn{roots}: any file under
2347 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2348 cannot be deleted; any other file is considered @dfn{dead} and may be
2349 deleted. The set of garbage collector roots (``GC roots'' for short)
2350 includes default user profiles; by default, the symlinks under
2351 @file{/var/guix/gcroots} represent these GC roots. New GC roots can be
2352 added with @command{guix build --root}, for example (@pxref{Invoking
2355 Prior to running @code{guix gc --collect-garbage} to make space, it is
2356 often useful to remove old generations from user profiles; that way, old
2357 package builds referenced by those generations can be reclaimed. This
2358 is achieved by running @code{guix package --delete-generations}
2359 (@pxref{Invoking guix package}).
2361 Our recommendation is to run a garbage collection periodically, or when
2362 you are short on disk space. For instance, to guarantee that at least
2363 5@tie{}GB are available on your disk, simply run:
2369 It is perfectly safe to run as a non-interactive periodic job
2370 (@pxref{Scheduled Job Execution}, for how to set up such a job on
2371 GuixSD). Running @command{guix gc} with no arguments will collect as
2372 much garbage as it can, but that is often inconvenient: you may find
2373 yourself having to rebuild or re-download software that is ``dead'' from
2374 the GC viewpoint but that is necessary to build other pieces of
2375 software---e.g., the compiler tool chain.
2377 The @command{guix gc} command has three modes of operation: it can be
2378 used to garbage-collect any dead files (the default), to delete specific
2379 files (the @code{--delete} option), to print garbage-collector
2380 information, or for more advanced queries. The garbage collection
2381 options are as follows:
2384 @item --collect-garbage[=@var{min}]
2385 @itemx -C [@var{min}]
2386 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2387 sub-directories. This is the default operation when no option is
2390 When @var{min} is given, stop once @var{min} bytes have been collected.
2391 @var{min} may be a number of bytes, or it may include a unit as a
2392 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2393 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2395 When @var{min} is omitted, collect all the garbage.
2397 @item --free-space=@var{free}
2398 @itemx -F @var{free}
2399 Collect garbage until @var{free} space is available under
2400 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2401 as @code{500MiB}, as described above.
2403 When @var{free} or more is already available in @file{/gnu/store}, do
2404 nothing and exit immediately.
2408 Attempt to delete all the store files and directories specified as
2409 arguments. This fails if some of the files are not in the store, or if
2410 they are still live.
2412 @item --list-failures
2413 List store items corresponding to cached build failures.
2415 This prints nothing unless the daemon was started with
2416 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2417 @option{--cache-failures}}).
2419 @item --clear-failures
2420 Remove the specified store items from the failed-build cache.
2422 Again, this option only makes sense when the daemon is started with
2423 @option{--cache-failures}. Otherwise, it does nothing.
2426 Show the list of dead files and directories still present in the
2427 store---i.e., files and directories no longer reachable from any root.
2430 Show the list of live store files and directories.
2434 In addition, the references among existing store files can be queried:
2440 @cindex package dependencies
2441 List the references (respectively, the referrers) of store files given
2447 List the requisites of the store files passed as arguments. Requisites
2448 include the store files themselves, their references, and the references
2449 of these, recursively. In other words, the returned list is the
2450 @dfn{transitive closure} of the store files.
2452 @xref{Invoking guix size}, for a tool to profile the size of the closure
2453 of an element. @xref{Invoking guix graph}, for a tool to visualize
2454 the graph of references.
2458 Lastly, the following options allow you to check the integrity of the
2459 store and to control disk usage.
2463 @item --verify[=@var{options}]
2464 @cindex integrity, of the store
2465 @cindex integrity checking
2466 Verify the integrity of the store.
2468 By default, make sure that all the store items marked as valid in the
2469 database of the daemon actually exist in @file{/gnu/store}.
2471 When provided, @var{options} must be a comma-separated list containing one
2472 or more of @code{contents} and @code{repair}.
2474 When passing @option{--verify=contents}, the daemon computes the
2475 content hash of each store item and compares it against its hash in the
2476 database. Hash mismatches are reported as data corruptions. Because it
2477 traverses @emph{all the files in the store}, this command can take a
2478 long time, especially on systems with a slow disk drive.
2480 @cindex repairing the store
2481 @cindex corruption, recovering from
2482 Using @option{--verify=repair} or @option{--verify=contents,repair}
2483 causes the daemon to try to repair corrupt store items by fetching
2484 substitutes for them (@pxref{Substitutes}). Because repairing is not
2485 atomic, and thus potentially dangerous, it is available only to the
2486 system administrator. A lightweight alternative, when you know exactly
2487 which items in the store are corrupt, is @command{guix build --repair}
2488 (@pxref{Invoking guix build}).
2491 @cindex deduplication
2492 Optimize the store by hard-linking identical files---this is
2493 @dfn{deduplication}.
2495 The daemon performs deduplication after each successful build or archive
2496 import, unless it was started with @code{--disable-deduplication}
2497 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2498 this option is primarily useful when the daemon was running with
2499 @code{--disable-deduplication}.
2503 @node Invoking guix pull
2504 @section Invoking @command{guix pull}
2506 @cindex upgrading Guix
2507 @cindex updating Guix
2508 @cindex @command{guix pull}
2510 Packages are installed or upgraded to the latest version available in
2511 the distribution currently available on your local machine. To update
2512 that distribution, along with the Guix tools, you must run @command{guix
2513 pull}: the command downloads the latest Guix source code and package
2514 descriptions, and deploys it. Source code is downloaded from a
2515 @uref{https://git-scm.com, Git} repository.
2517 On completion, @command{guix package} will use packages and package
2518 versions from this just-retrieved copy of Guix. Not only that, but all
2519 the Guix commands and Scheme modules will also be taken from that latest
2520 version. New @command{guix} sub-commands added by the update also
2523 Any user can update their Guix copy using @command{guix pull}, and the
2524 effect is limited to the user who run @command{guix pull}. For
2525 instance, when user @code{root} runs @command{guix pull}, this has no
2526 effect on the version of Guix that user @code{alice} sees, and vice
2527 versa@footnote{Under the hood, @command{guix pull} updates the
2528 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2529 and the @command{guix} command loads code from there. Currently, the
2530 only way to roll back an invocation of @command{guix pull} is to
2531 manually update this symlink to point to the previous Guix.}.
2533 The @command{guix pull} command is usually invoked with no arguments,
2534 but it supports the following options:
2538 Produce verbose output, writing build logs to the standard error output.
2540 @item --url=@var{url}
2541 Download Guix from the Git repository at @var{url}.
2543 @vindex GUIX_PULL_URL
2544 By default, the source is taken from its canonical Git repository at
2545 @code{gnu.org}, for the stable branch of Guix. To use a different source,
2546 set the @code{GUIX_PULL_URL} environment variable.
2548 @item --commit=@var{commit}
2549 Deploy @var{commit}, a valid Git commit ID represented as a hexadecimal
2552 @item --branch=@var{branch}
2553 Deploy the tip of @var{branch}, the name of a Git branch available on
2554 the repository at @var{url}.
2557 Use the bootstrap Guile to build the latest Guix. This option is only
2558 useful to Guix developers.
2561 In addition, @command{guix pull} supports all the common build options
2562 (@pxref{Common Build Options}).
2564 @node Invoking guix pack
2565 @section Invoking @command{guix pack}
2567 Occasionally you want to pass software to people who are not (yet!)
2568 lucky enough to be using Guix. You'd tell them to run @command{guix
2569 package -i @var{something}}, but that's not possible in this case. This
2570 is where @command{guix pack} comes in.
2574 @cindex application bundle
2575 @cindex software bundle
2576 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2577 @dfn{software bundle}: it creates a tarball or some other archive
2578 containing the binaries of the software you're interested in, and all
2579 its dependencies. The resulting archive can be used on any machine that
2580 does not have Guix, and people can run the exact same binaries as those
2581 you have with Guix. The pack itself is created in a bit-reproducible
2582 fashion, so anyone can verify that it really contains the build results
2583 that you pretend to be shipping.
2585 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2586 their dependencies, you can run:
2589 $ guix pack guile emacs geiser
2591 /gnu/store/@dots{}-pack.tar.gz
2594 The result here is a tarball containing a @file{/gnu/store} directory
2595 with all the relevant packages. The resulting tarball contains a
2596 @dfn{profile} with the three packages of interest; the profile is the
2597 same as would be created by @command{guix package -i}. It is this
2598 mechanism that is used to create Guix's own standalone binary tarball
2599 (@pxref{Binary Installation}).
2601 Users of this pack would have to run
2602 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2603 find inconvenient. To work around it, you can create, say, a
2604 @file{/opt/gnu/bin} symlink to the profile:
2607 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2611 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2613 Alternatively, you can produce a pack in the Docker image format using
2614 the following command:
2617 guix pack -f docker guile emacs geiser
2621 The result is a tarball that can be passed to the @command{docker load}
2623 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2624 documentation} for more information.
2626 Several command-line options allow you to customize your pack:
2629 @item --format=@var{format}
2630 @itemx -f @var{format}
2631 Produce a pack in the given @var{format}.
2633 The available formats are:
2637 This is the default format. It produces a tarball containing all the
2638 specified binaries and symlinks.
2641 This produces a tarball that follows the
2642 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2643 Docker Image Specification}.
2646 @item --expression=@var{expr}
2647 @itemx -e @var{expr}
2648 Consider the package @var{expr} evaluates to.
2650 This has the same purpose as the same-named option in @command{guix
2651 build} (@pxref{Additional Build Options, @code{--expression} in
2652 @command{guix build}}).
2654 @item --system=@var{system}
2655 @itemx -s @var{system}
2656 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2657 the system type of the build host.
2659 @item --target=@var{triplet}
2660 @cindex cross-compilation
2661 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2662 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2663 configuration triplets,, autoconf, Autoconf}).
2665 @item --compression=@var{tool}
2666 @itemx -C @var{tool}
2667 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2668 @code{bzip2}, @code{xz}, @code{lzip}, or @code{none} for no compression.
2670 @item --symlink=@var{spec}
2671 @itemx -S @var{spec}
2672 Add the symlinks specified by @var{spec} to the pack. This option can
2673 appear several times.
2675 @var{spec} has the form @code{@var{source}=@var{target}}, where
2676 @var{source} is the symlink that will be created and @var{target} is the
2679 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2680 symlink pointing to the @file{bin} sub-directory of the profile.
2682 @item --localstatedir
2683 Include the ``local state directory'', @file{/var/guix}, in the
2686 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2687 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2688 the pack means that the store is ``complete'' and manageable by Guix;
2689 not providing it pack means that the store is ``dead'': items cannot be
2690 added to it or removed from it after extraction of the pack.
2692 One use case for this is the Guix self-contained binary tarball
2693 (@pxref{Binary Installation}).
2696 In addition, @command{guix pack} supports all the common build options
2697 (@pxref{Common Build Options}) and all the package transformation
2698 options (@pxref{Package Transformation Options}).
2701 @node Invoking guix archive
2702 @section Invoking @command{guix archive}
2704 @cindex @command{guix archive}
2706 The @command{guix archive} command allows users to @dfn{export} files
2707 from the store into a single archive, and to later @dfn{import} them.
2708 In particular, it allows store files to be transferred from one machine
2709 to the store on another machine.
2711 @cindex exporting store items
2712 To export store files as an archive to standard output, run:
2715 guix archive --export @var{options} @var{specifications}...
2718 @var{specifications} may be either store file names or package
2719 specifications, as for @command{guix package} (@pxref{Invoking guix
2720 package}). For instance, the following command creates an archive
2721 containing the @code{gui} output of the @code{git} package and the main
2722 output of @code{emacs}:
2725 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2728 If the specified packages are not built yet, @command{guix archive}
2729 automatically builds them. The build process may be controlled with the
2730 common build options (@pxref{Common Build Options}).
2732 To transfer the @code{emacs} package to a machine connected over SSH,
2736 guix archive --export -r emacs | ssh the-machine guix archive --import
2740 Similarly, a complete user profile may be transferred from one machine
2741 to another like this:
2744 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2745 ssh the-machine guix-archive --import
2749 However, note that, in both examples, all of @code{emacs} and the
2750 profile as well as all of their dependencies are transferred (due to
2751 @code{-r}), regardless of what is already available in the store on the
2752 target machine. The @code{--missing} option can help figure out which
2753 items are missing from the target store. The @command{guix copy}
2754 command simplifies and optimizes this whole process, so this is probably
2755 what you should use in this case (@pxref{Invoking guix copy}).
2757 @cindex nar, archive format
2758 @cindex normalized archive (nar)
2759 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2760 comparable in spirit to `tar', but with differences
2761 that make it more appropriate for our purposes. First, rather than
2762 recording all Unix metadata for each file, the nar format only mentions
2763 the file type (regular, directory, or symbolic link); Unix permissions
2764 and owner/group are dismissed. Second, the order in which directory
2765 entries are stored always follows the order of file names according to
2766 the C locale collation order. This makes archive production fully
2769 When exporting, the daemon digitally signs the contents of the archive,
2770 and that digital signature is appended. When importing, the daemon
2771 verifies the signature and rejects the import in case of an invalid
2772 signature or if the signing key is not authorized.
2773 @c FIXME: Add xref to daemon doc about signatures.
2775 The main options are:
2779 Export the specified store files or packages (see below.) Write the
2780 resulting archive to the standard output.
2782 Dependencies are @emph{not} included in the output, unless
2783 @code{--recursive} is passed.
2787 When combined with @code{--export}, this instructs @command{guix
2788 archive} to include dependencies of the given items in the archive.
2789 Thus, the resulting archive is self-contained: it contains the closure
2790 of the exported store items.
2793 Read an archive from the standard input, and import the files listed
2794 therein into the store. Abort if the archive has an invalid digital
2795 signature, or if it is signed by a public key not among the authorized
2796 keys (see @code{--authorize} below.)
2799 Read a list of store file names from the standard input, one per line,
2800 and write on the standard output the subset of these files missing from
2803 @item --generate-key[=@var{parameters}]
2804 @cindex signing, archives
2805 Generate a new key pair for the daemon. This is a prerequisite before
2806 archives can be exported with @code{--export}. Note that this operation
2807 usually takes time, because it needs to gather enough entropy to
2808 generate the key pair.
2810 The generated key pair is typically stored under @file{/etc/guix}, in
2811 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2812 key, which must be kept secret.) When @var{parameters} is omitted,
2813 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2814 versions before 1.6.0, it is a 4096-bit RSA key.
2815 Alternatively, @var{parameters} can specify
2816 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2817 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2818 Libgcrypt Reference Manual}).
2821 @cindex authorizing, archives
2822 Authorize imports signed by the public key passed on standard input.
2823 The public key must be in ``s-expression advanced format''---i.e., the
2824 same format as the @file{signing-key.pub} file.
2826 The list of authorized keys is kept in the human-editable file
2827 @file{/etc/guix/acl}. The file contains
2828 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2829 s-expressions''} and is structured as an access-control list in the
2830 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2833 @item --extract=@var{directory}
2834 @itemx -x @var{directory}
2835 Read a single-item archive as served by substitute servers
2836 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2837 low-level operation needed in only very narrow use cases; see below.
2839 For example, the following command extracts the substitute for Emacs
2840 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2844 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2845 | bunzip2 | guix archive -x /tmp/emacs
2848 Single-item archives are different from multiple-item archives produced
2849 by @command{guix archive --export}; they contain a single store item,
2850 and they do @emph{not} embed a signature. Thus this operation does
2851 @emph{no} signature verification and its output should be considered
2854 The primary purpose of this operation is to facilitate inspection of
2855 archive contents coming from possibly untrusted substitute servers.
2859 @c *********************************************************************
2860 @node Programming Interface
2861 @chapter Programming Interface
2863 GNU Guix provides several Scheme programming interfaces (APIs) to
2864 define, build, and query packages. The first interface allows users to
2865 write high-level package definitions. These definitions refer to
2866 familiar packaging concepts, such as the name and version of a package,
2867 its build system, and its dependencies. These definitions can then be
2868 turned into concrete build actions.
2870 Build actions are performed by the Guix daemon, on behalf of users. In a
2871 standard setup, the daemon has write access to the store---the
2872 @file{/gnu/store} directory---whereas users do not. The recommended
2873 setup also has the daemon perform builds in chroots, under a specific
2874 build users, to minimize interference with the rest of the system.
2877 Lower-level APIs are available to interact with the daemon and the
2878 store. To instruct the daemon to perform a build action, users actually
2879 provide it with a @dfn{derivation}. A derivation is a low-level
2880 representation of the build actions to be taken, and the environment in
2881 which they should occur---derivations are to package definitions what
2882 assembly is to C programs. The term ``derivation'' comes from the fact
2883 that build results @emph{derive} from them.
2885 This chapter describes all these APIs in turn, starting from high-level
2886 package definitions.
2889 * Defining Packages:: Defining new packages.
2890 * Build Systems:: Specifying how packages are built.
2891 * The Store:: Manipulating the package store.
2892 * Derivations:: Low-level interface to package derivations.
2893 * The Store Monad:: Purely functional interface to the store.
2894 * G-Expressions:: Manipulating build expressions.
2897 @node Defining Packages
2898 @section Defining Packages
2900 The high-level interface to package definitions is implemented in the
2901 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2902 example, the package definition, or @dfn{recipe}, for the GNU Hello
2903 package looks like this:
2906 (define-module (gnu packages hello)
2907 #:use-module (guix packages)
2908 #:use-module (guix download)
2909 #:use-module (guix build-system gnu)
2910 #:use-module (guix licenses)
2911 #:use-module (gnu packages gawk))
2913 (define-public hello
2919 (uri (string-append "mirror://gnu/hello/hello-" version
2923 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2924 (build-system gnu-build-system)
2925 (arguments '(#:configure-flags '("--enable-silent-rules")))
2926 (inputs `(("gawk" ,gawk)))
2927 (synopsis "Hello, GNU world: An example GNU package")
2928 (description "Guess what GNU Hello prints!")
2929 (home-page "http://www.gnu.org/software/hello/")
2934 Without being a Scheme expert, the reader may have guessed the meaning
2935 of the various fields here. This expression binds the variable
2936 @code{hello} to a @code{<package>} object, which is essentially a record
2937 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2938 This package object can be inspected using procedures found in the
2939 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2940 returns---surprise!---@code{"hello"}.
2942 With luck, you may be able to import part or all of the definition of
2943 the package you are interested in from another repository, using the
2944 @code{guix import} command (@pxref{Invoking guix import}).
2946 In the example above, @var{hello} is defined in a module of its own,
2947 @code{(gnu packages hello)}. Technically, this is not strictly
2948 necessary, but it is convenient to do so: all the packages defined in
2949 modules under @code{(gnu packages @dots{})} are automatically known to
2950 the command-line tools (@pxref{Package Modules}).
2952 There are a few points worth noting in the above package definition:
2956 The @code{source} field of the package is an @code{<origin>} object
2957 (@pxref{origin Reference}, for the complete reference).
2958 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2959 meaning that the source is a file to be downloaded over FTP or HTTP.
2961 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2962 the GNU mirrors defined in @code{(guix download)}.
2964 The @code{sha256} field specifies the expected SHA256 hash of the file
2965 being downloaded. It is mandatory, and allows Guix to check the
2966 integrity of the file. The @code{(base32 @dots{})} form introduces the
2967 base32 representation of the hash. You can obtain this information with
2968 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2969 hash} (@pxref{Invoking guix hash}).
2972 When needed, the @code{origin} form can also have a @code{patches} field
2973 listing patches to be applied, and a @code{snippet} field giving a
2974 Scheme expression to modify the source code.
2977 @cindex GNU Build System
2978 The @code{build-system} field specifies the procedure to build the
2979 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2980 represents the familiar GNU Build System, where packages may be
2981 configured, built, and installed with the usual @code{./configure &&
2982 make && make check && make install} command sequence.
2985 The @code{arguments} field specifies options for the build system
2986 (@pxref{Build Systems}). Here it is interpreted by
2987 @var{gnu-build-system} as a request run @file{configure} with the
2988 @code{--enable-silent-rules} flag.
2994 What about these quote (@code{'}) characters? They are Scheme syntax to
2995 introduce a literal list; @code{'} is synonymous with @code{quote}.
2996 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2997 for details. Here the value of the @code{arguments} field is a list of
2998 arguments passed to the build system down the road, as with @code{apply}
2999 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
3002 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
3003 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
3004 @code{#:configure-flags} is a keyword used to pass a keyword argument
3005 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
3009 The @code{inputs} field specifies inputs to the build process---i.e.,
3010 build-time or run-time dependencies of the package. Here, we define an
3011 input called @code{"gawk"} whose value is that of the @var{gawk}
3012 variable; @var{gawk} is itself bound to a @code{<package>} object.
3014 @cindex backquote (quasiquote)
3017 @cindex comma (unquote)
3021 @findex unquote-splicing
3022 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
3023 us to introduce a literal list in the @code{inputs} field, while
3024 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
3025 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
3028 Note that GCC, Coreutils, Bash, and other essential tools do not need to
3029 be specified as inputs here. Instead, @var{gnu-build-system} takes care
3030 of ensuring that they are present (@pxref{Build Systems}).
3032 However, any other dependencies need to be specified in the
3033 @code{inputs} field. Any dependency not specified here will simply be
3034 unavailable to the build process, possibly leading to a build failure.
3037 @xref{package Reference}, for a full description of possible fields.
3039 Once a package definition is in place, the
3040 package may actually be built using the @code{guix build} command-line
3041 tool (@pxref{Invoking guix build}), troubleshooting any build failures
3042 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
3043 package definition using the @command{guix edit} command
3044 (@pxref{Invoking guix edit}).
3045 @xref{Packaging Guidelines}, for
3046 more information on how to test package definitions, and
3047 @ref{Invoking guix lint}, for information on how to check a definition
3048 for style conformance.
3049 @vindex GUIX_PACKAGE_PATH
3050 Lastly, @pxref{Package Modules}, for information
3051 on how to extend the distribution by adding your own package definitions
3052 to @code{GUIX_PACKAGE_PATH}.
3054 Finally, updating the package definition to a new upstream version
3055 can be partly automated by the @command{guix refresh} command
3056 (@pxref{Invoking guix refresh}).
3058 Behind the scenes, a derivation corresponding to the @code{<package>}
3059 object is first computed by the @code{package-derivation} procedure.
3060 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
3061 The build actions it prescribes may then be realized by using the
3062 @code{build-derivations} procedure (@pxref{The Store}).
3064 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
3065 Return the @code{<derivation>} object of @var{package} for @var{system}
3066 (@pxref{Derivations}).
3068 @var{package} must be a valid @code{<package>} object, and @var{system}
3069 must be a string denoting the target system type---e.g.,
3070 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
3071 must be a connection to the daemon, which operates on the store
3072 (@pxref{The Store}).
3076 @cindex cross-compilation
3077 Similarly, it is possible to compute a derivation that cross-builds a
3078 package for some other system:
3080 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
3081 @var{package} @var{target} [@var{system}]
3082 Return the @code{<derivation>} object of @var{package} cross-built from
3083 @var{system} to @var{target}.
3085 @var{target} must be a valid GNU triplet denoting the target hardware
3086 and operating system, such as @code{"mips64el-linux-gnu"}
3087 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
3088 Configure and Build System}).
3091 @cindex package transformations
3092 @cindex input rewriting
3093 @cindex dependency tree rewriting
3094 Packages can be manipulated in arbitrary ways. An example of a useful
3095 transformation is @dfn{input rewriting}, whereby the dependency tree of
3096 a package is rewritten by replacing specific inputs by others:
3098 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
3099 [@var{rewrite-name}]
3100 Return a procedure that, when passed a package, replaces its direct and
3101 indirect dependencies (but not its implicit inputs) according to
3102 @var{replacements}. @var{replacements} is a list of package pairs; the
3103 first element of each pair is the package to replace, and the second one
3106 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3107 the name of a package and returns its new name after rewrite.
3111 Consider this example:
3114 (define libressl-instead-of-openssl
3115 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3117 (package-input-rewriting `((,openssl . ,libressl))))
3119 (define git-with-libressl
3120 (libressl-instead-of-openssl git))
3124 Here we first define a rewriting procedure that replaces @var{openssl}
3125 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3126 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3127 This is exactly what the @option{--with-input} command-line option does
3128 (@pxref{Package Transformation Options, @option{--with-input}}).
3130 A more generic procedure to rewrite a package dependency graph is
3131 @code{package-mapping}: it supports arbitrary changes to nodes in the
3134 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3135 Return a procedure that, given a package, applies @var{proc} to all the packages
3136 depended on and returns the resulting package. The procedure stops recursion
3137 when @var{cut?} returns true for a given package.
3141 * package Reference :: The package data type.
3142 * origin Reference:: The origin data type.
3146 @node package Reference
3147 @subsection @code{package} Reference
3149 This section summarizes all the options available in @code{package}
3150 declarations (@pxref{Defining Packages}).
3152 @deftp {Data Type} package
3153 This is the data type representing a package recipe.
3157 The name of the package, as a string.
3159 @item @code{version}
3160 The version of the package, as a string.
3163 An object telling how the source code for the package should be
3164 acquired. Most of the time, this is an @code{origin} object, which
3165 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3166 can also be any other ``file-like'' object such as a @code{local-file},
3167 which denotes a file from the local file system (@pxref{G-Expressions,
3168 @code{local-file}}).
3170 @item @code{build-system}
3171 The build system that should be used to build the package (@pxref{Build
3174 @item @code{arguments} (default: @code{'()})
3175 The arguments that should be passed to the build system. This is a
3176 list, typically containing sequential keyword-value pairs.
3178 @item @code{inputs} (default: @code{'()})
3179 @itemx @code{native-inputs} (default: @code{'()})
3180 @itemx @code{propagated-inputs} (default: @code{'()})
3181 @cindex inputs, of packages
3182 These fields list dependencies of the package. Each one is a list of
3183 tuples, where each tuple has a label for the input (a string) as its
3184 first element, a package, origin, or derivation as its second element,
3185 and optionally the name of the output thereof that should be used, which
3186 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3187 more on package outputs). For example, the list below specifies three
3191 `(("libffi" ,libffi)
3192 ("libunistring" ,libunistring)
3193 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3196 @cindex cross compilation, package dependencies
3197 The distinction between @code{native-inputs} and @code{inputs} is
3198 necessary when considering cross-compilation. When cross-compiling,
3199 dependencies listed in @code{inputs} are built for the @emph{target}
3200 architecture; conversely, dependencies listed in @code{native-inputs}
3201 are built for the architecture of the @emph{build} machine.
3203 @code{native-inputs} is typically used to list tools needed at
3204 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3205 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3206 this area (@pxref{Invoking guix lint}).
3208 @anchor{package-propagated-inputs}
3209 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3210 specified packages will be automatically installed alongside the package
3211 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3212 package}}, for information on how @command{guix package} deals with
3215 For example this is necessary when a C/C++ library needs headers of
3216 another library to compile, or when a pkg-config file refers to another
3217 one @i{via} its @code{Requires} field.
3219 Another example where @code{propagated-inputs} is useful is for languages
3220 that lack a facility to record the run-time search path akin to the
3221 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3222 more. To ensure that libraries written in those languages can find
3223 library code they depend on at run time, run-time dependencies must be
3224 listed in @code{propagated-inputs} rather than @code{inputs}.
3226 @item @code{self-native-input?} (default: @code{#f})
3227 This is a Boolean field telling whether the package should use itself as
3228 a native input when cross-compiling.
3230 @item @code{outputs} (default: @code{'("out")})
3231 The list of output names of the package. @xref{Packages with Multiple
3232 Outputs}, for typical uses of additional outputs.
3234 @item @code{native-search-paths} (default: @code{'()})
3235 @itemx @code{search-paths} (default: @code{'()})
3236 A list of @code{search-path-specification} objects describing
3237 search-path environment variables honored by the package.
3239 @item @code{replacement} (default: @code{#f})
3240 This must be either @code{#f} or a package object that will be used as a
3241 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3244 @item @code{synopsis}
3245 A one-line description of the package.
3247 @item @code{description}
3248 A more elaborate description of the package.
3250 @item @code{license}
3251 @cindex license, of packages
3252 The license of the package; a value from @code{(guix licenses)},
3253 or a list of such values.
3255 @item @code{home-page}
3256 The URL to the home-page of the package, as a string.
3258 @item @code{supported-systems} (default: @var{%supported-systems})
3259 The list of systems supported by the package, as strings of the form
3260 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3262 @item @code{maintainers} (default: @code{'()})
3263 The list of maintainers of the package, as @code{maintainer} objects.
3265 @item @code{location} (default: source location of the @code{package} form)
3266 The source location of the package. It is useful to override this when
3267 inheriting from another package, in which case this field is not
3268 automatically corrected.
3273 @node origin Reference
3274 @subsection @code{origin} Reference
3276 This section summarizes all the options available in @code{origin}
3277 declarations (@pxref{Defining Packages}).
3279 @deftp {Data Type} origin
3280 This is the data type representing a source code origin.
3284 An object containing the URI of the source. The object type depends on
3285 the @code{method} (see below). For example, when using the
3286 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3287 values are: a URL represented as a string, or a list thereof.
3290 A procedure that handles the URI.
3295 @item @var{url-fetch} from @code{(guix download)}
3296 download a file from the HTTP, HTTPS, or FTP URL specified in the
3300 @item @var{git-fetch} from @code{(guix git-download)}
3301 clone the Git version control repository, and check out the revision
3302 specified in the @code{uri} field as a @code{git-reference} object; a
3303 @code{git-reference} looks like this:
3307 (url "git://git.debian.org/git/pkg-shadow/shadow")
3308 (commit "v4.1.5.1"))
3313 A bytevector containing the SHA-256 hash of the source. Typically the
3314 @code{base32} form is used here to generate the bytevector from a
3317 You can obtain this information using @code{guix download}
3318 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3321 @item @code{file-name} (default: @code{#f})
3322 The file name under which the source code should be saved. When this is
3323 @code{#f}, a sensible default value will be used in most cases. In case
3324 the source is fetched from a URL, the file name from the URL will be
3325 used. For version control checkouts, it is recommended to provide the
3326 file name explicitly because the default is not very descriptive.
3328 @item @code{patches} (default: @code{'()})
3329 A list of file names, origins, or file-like objects (@pxref{G-Expressions,
3330 file-like objects}) pointing to patches to be applied to the source.
3332 This list of patches must be unconditional. In particular, it cannot
3333 depend on the value of @code{%current-system} or
3334 @code{%current-target-system}.
3336 @item @code{snippet} (default: @code{#f})
3337 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3338 in the source directory. This is a convenient way to modify the source,
3339 sometimes more convenient than a patch.
3341 @item @code{patch-flags} (default: @code{'("-p1")})
3342 A list of command-line flags that should be passed to the @code{patch}
3345 @item @code{patch-inputs} (default: @code{#f})
3346 Input packages or derivations to the patching process. When this is
3347 @code{#f}, the usual set of inputs necessary for patching are provided,
3348 such as GNU@tie{}Patch.
3350 @item @code{modules} (default: @code{'()})
3351 A list of Guile modules that should be loaded during the patching
3352 process and while running the code in the @code{snippet} field.
3354 @item @code{patch-guile} (default: @code{#f})
3355 The Guile package that should be used in the patching process. When
3356 this is @code{#f}, a sensible default is used.
3362 @section Build Systems
3364 @cindex build system
3365 Each package definition specifies a @dfn{build system} and arguments for
3366 that build system (@pxref{Defining Packages}). This @code{build-system}
3367 field represents the build procedure of the package, as well as implicit
3368 dependencies of that build procedure.
3370 Build systems are @code{<build-system>} objects. The interface to
3371 create and manipulate them is provided by the @code{(guix build-system)}
3372 module, and actual build systems are exported by specific modules.
3374 @cindex bag (low-level package representation)
3375 Under the hood, build systems first compile package objects to
3376 @dfn{bags}. A @dfn{bag} is like a package, but with less
3377 ornamentation---in other words, a bag is a lower-level representation of
3378 a package, which includes all the inputs of that package, including some
3379 that were implicitly added by the build system. This intermediate
3380 representation is then compiled to a derivation (@pxref{Derivations}).
3382 Build systems accept an optional list of @dfn{arguments}. In package
3383 definitions, these are passed @i{via} the @code{arguments} field
3384 (@pxref{Defining Packages}). They are typically keyword arguments
3385 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3386 Guile Reference Manual}). The value of these arguments is usually
3387 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3388 by the daemon (@pxref{Derivations}).
3390 The main build system is @var{gnu-build-system}, which implements the
3391 standard build procedure for GNU and many other packages. It
3392 is provided by the @code{(guix build-system gnu)} module.
3394 @defvr {Scheme Variable} gnu-build-system
3395 @var{gnu-build-system} represents the GNU Build System, and variants
3396 thereof (@pxref{Configuration, configuration and makefile conventions,,
3397 standards, GNU Coding Standards}).
3399 @cindex build phases
3400 In a nutshell, packages using it are configured, built, and installed with
3401 the usual @code{./configure && make && make check && make install}
3402 command sequence. In practice, a few additional steps are often needed.
3403 All these steps are split up in separate @dfn{phases},
3404 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3405 modules for more details about the build phases.}:
3409 Unpack the source tarball, and change the current directory to the
3410 extracted source tree. If the source is actually a directory, copy it
3411 to the build tree, and enter that directory.
3413 @item patch-source-shebangs
3414 Patch shebangs encountered in source files so they refer to the right
3415 store file names. For instance, this changes @code{#!/bin/sh} to
3416 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3419 Run the @file{configure} script with a number of default options, such
3420 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3421 by the @code{#:configure-flags} argument.
3424 Run @code{make} with the list of flags specified with
3425 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3426 (the default), build with @code{make -j}.
3429 Run @code{make check}, or some other target specified with
3430 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3431 @code{#:parallel-tests?} argument is true (the default), run @code{make
3435 Run @code{make install} with the flags listed in @code{#:make-flags}.
3437 @item patch-shebangs
3438 Patch shebangs on the installed executable files.
3441 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3442 is false), copying them to the @code{debug} output when available
3443 (@pxref{Installing Debugging Files}).
3446 @vindex %standard-phases
3447 The build-side module @code{(guix build gnu-build-system)} defines
3448 @var{%standard-phases} as the default list of build phases.
3449 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3450 procedure implements the actual phase.
3452 The list of phases used for a particular package can be changed with the
3453 @code{#:phases} parameter. For instance, passing:
3456 #:phases (modify-phases %standard-phases (delete 'configure))
3459 means that all the phases described above will be used, except the
3460 @code{configure} phase.
3462 In addition, this build system ensures that the ``standard'' environment
3463 for GNU packages is available. This includes tools such as GCC, libc,
3464 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3465 build-system gnu)} module for a complete list). We call these the
3466 @dfn{implicit inputs} of a package, because package definitions do not
3467 have to mention them.
3470 Other @code{<build-system>} objects are defined to support other
3471 conventions and tools used by free software packages. They inherit most
3472 of @var{gnu-build-system}, and differ mainly in the set of inputs
3473 implicitly added to the build process, and in the list of phases
3474 executed. Some of these build systems are listed below.
3476 @defvr {Scheme Variable} ant-build-system
3477 This variable is exported by @code{(guix build-system ant)}. It
3478 implements the build procedure for Java packages that can be built with
3479 @url{http://ant.apache.org/, Ant build tool}.
3481 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3482 provided by the @code{icedtea} package to the set of inputs. Different
3483 packages can be specified with the @code{#:ant} and @code{#:jdk}
3484 parameters, respectively.
3486 When the original package does not provide a suitable Ant build file,
3487 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3488 build file @file{build.xml} with tasks to build the specified jar
3489 archive. In this case the parameter @code{#:source-dir} can be used to
3490 specify the source sub-directory, defaulting to ``src''.
3492 The @code{#:main-class} parameter can be used with the minimal ant
3493 buildfile to specify the main class of the resulting jar. This makes the
3494 jar file executable. The @code{#:test-include} parameter can be used to
3495 specify the list of junit tests to run. It defaults to
3496 @code{(list "**/*Test.java")}. The @code{#:test-exclude} can be used to
3497 disable some tests. It defaults to @code{(list "**/Abstract*.java")},
3498 because abstract classes cannot be run as tests.
3500 The parameter @code{#:build-target} can be used to specify the Ant task
3501 that should be run during the @code{build} phase. By default the
3502 ``jar'' task will be run.
3506 @defvr {Scheme Variable} asdf-build-system/source
3507 @defvrx {Scheme Variable} asdf-build-system/sbcl
3508 @defvrx {Scheme Variable} asdf-build-system/ecl
3510 These variables, exported by @code{(guix build-system asdf)}, implement
3511 build procedures for Common Lisp packages using
3512 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3513 definition facility for Common Lisp programs and libraries.
3515 The @code{asdf-build-system/source} system installs the packages in
3516 source form, and can be loaded using any common lisp implementation, via
3517 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3518 systems in the format which a particular implementation understands.
3519 These build systems can also be used to produce executable programs, or
3520 lisp images which contain a set of packages pre-loaded.
3522 The build system uses naming conventions. For binary packages, the
3523 package name should be prefixed with the lisp implementation, such as
3524 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3526 Additionally, the corresponding source package should be labeled using
3527 the same convention as python packages (see @ref{Python Modules}), using
3528 the @code{cl-} prefix.
3530 For binary packages, each system should be defined as a Guix package.
3531 If one package @code{origin} contains several systems, package variants
3532 can be created in order to build all the systems. Source packages,
3533 which use @code{asdf-build-system/source}, may contain several systems.
3535 In order to create executable programs and images, the build-side
3536 procedures @code{build-program} and @code{build-image} can be used.
3537 They should be called in a build phase after the @code{create-symlinks}
3538 phase, so that the system which was just built can be used within the
3539 resulting image. @code{build-program} requires a list of Common Lisp
3540 expressions to be passed as the @code{#:entry-program} argument.
3542 If the system is not defined within its own @code{.asd} file of the same
3543 name, then the @code{#:asd-file} parameter should be used to specify
3544 which file the system is defined in. Furthermore, if the package
3545 defines a system for its tests in a separate file, it will be loaded
3546 before the tests are run if it is specified by the
3547 @code{#:test-asd-file} parameter. If it is not set, the files
3548 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3549 and @code{test.asd} will be tried if they exist.
3551 If for some reason the package must be named in a different way than the
3552 naming conventions suggest, the @code{#:asd-system-name} parameter can
3553 be used to specify the name of the system.
3557 @defvr {Scheme Variable} cargo-build-system
3558 @cindex Rust programming language
3559 @cindex Cargo (Rust build system)
3560 This variable is exported by @code{(guix build-system cargo)}. It
3561 supports builds of packages using Cargo, the build tool of the
3562 @uref{https://www.rust-lang.org, Rust programming language}.
3564 In its @code{configure} phase, this build system replaces dependencies
3565 specified in the @file{Carto.toml} file with inputs to the Guix package.
3566 The @code{install} phase installs the binaries, and it also installs the
3567 source code and @file{Cargo.toml} file.
3570 @defvr {Scheme Variable} cmake-build-system
3571 This variable is exported by @code{(guix build-system cmake)}. It
3572 implements the build procedure for packages using the
3573 @url{http://www.cmake.org, CMake build tool}.
3575 It automatically adds the @code{cmake} package to the set of inputs.
3576 Which package is used can be specified with the @code{#:cmake}
3579 The @code{#:configure-flags} parameter is taken as a list of flags
3580 passed to the @command{cmake} command. The @code{#:build-type}
3581 parameter specifies in abstract terms the flags passed to the compiler;
3582 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3583 debugging information''), which roughly means that code is compiled with
3584 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3587 @defvr {Scheme Variable} go-build-system
3588 This variable is exported by @code{(guix build-system go)}. It
3589 implements a build procedure for Go packages using the standard
3590 @url{https://golang.org/cmd/go/#hdr-Compile_packages_and_dependencies,
3591 Go build mechanisms}.
3593 The user is expected to provide a value for the key @code{#:import-path}
3594 and, in some cases, @code{#:unpack-path}. The
3595 @url{https://golang.org/doc/code.html#ImportPaths, import path}
3596 corresponds to the filesystem path expected by the package's build
3597 scripts and any referring packages, and provides a unique way to
3598 refer to a Go package. It is typically based on a combination of the
3599 package source code's remote URI and filesystem hierarchy structure. In
3600 some cases, you will need to unpack the package's source code to a
3601 different directory structure than the one indicated by the import path,
3602 and @code{#:unpack-path} should be used in such cases.
3604 Packages that provide Go libraries should be installed along with their
3605 source code. The key @code{#:install-source?}, which defaults to
3606 @code{#t}, controls whether or not the source code is installed. It can
3607 be set to @code{#f} for packages that only provide executable files.
3610 @defvr {Scheme Variable} glib-or-gtk-build-system
3611 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3612 is intended for use with packages making use of GLib or GTK+.
3614 This build system adds the following two phases to the ones defined by
3615 @var{gnu-build-system}:
3618 @item glib-or-gtk-wrap
3619 The phase @code{glib-or-gtk-wrap} ensures that programs in
3620 @file{bin/} are able to find GLib ``schemas'' and
3621 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3622 modules}. This is achieved by wrapping the programs in launch scripts
3623 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3624 environment variables.
3626 It is possible to exclude specific package outputs from that wrapping
3627 process by listing their names in the
3628 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3629 when an output is known not to contain any GLib or GTK+ binaries, and
3630 where wrapping would gratuitously add a dependency of that output on
3633 @item glib-or-gtk-compile-schemas
3634 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3635 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3636 GSettings schemas} of GLib are compiled. Compilation is performed by the
3637 @command{glib-compile-schemas} program. It is provided by the package
3638 @code{glib:bin} which is automatically imported by the build system.
3639 The @code{glib} package providing @command{glib-compile-schemas} can be
3640 specified with the @code{#:glib} parameter.
3643 Both phases are executed after the @code{install} phase.
3646 @defvr {Scheme Variable} minify-build-system
3647 This variable is exported by @code{(guix build-system minify)}. It
3648 implements a minification procedure for simple JavaScript packages.
3650 It adds @code{uglify-js} to the set of inputs and uses it to compress
3651 all JavaScript files in the @file{src} directory. A different minifier
3652 package can be specified with the @code{#:uglify-js} parameter, but it
3653 is expected that the package writes the minified code to the standard
3656 When the input JavaScript files are not all located in the @file{src}
3657 directory, the parameter @code{#:javascript-files} can be used to
3658 specify a list of file names to feed to the minifier.
3661 @defvr {Scheme Variable} ocaml-build-system
3662 This variable is exported by @code{(guix build-system ocaml)}. It implements
3663 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3664 of choosing the correct set of commands to run for each package. OCaml
3665 packages can expect many different commands to be run. This build system will
3668 When the package has a @file{setup.ml} file present at the top-level, it will
3669 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3670 @code{ocaml setup.ml -install}. The build system will assume that this file
3671 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3672 care of setting the prefix and enabling tests if they are not disabled. You
3673 can pass configure and build flags with the @code{#:configure-flags} and
3674 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3675 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3676 bypass this system in the build and install phases.
3678 When the package has a @file{configure} file, it is assumed that it is a
3679 hand-made configure script that requires a different argument format than
3680 in the @code{gnu-build-system}. You can add more flags with the
3681 @code{#:configure-flags} key.
3683 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3684 @code{#t}), it will be used and more flags can be passed to the build and
3685 install phases with the @code{#:make-flags} key.
3687 Finally, some packages do not have these files and use a somewhat standard
3688 location for its build system. In that case, the build system will run
3689 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3690 providing the path to the required findlib module. Additional flags can
3691 be passed via the @code{#:build-flags} key. Install is taken care of by
3692 @command{opam-installer}. In this case, the @code{opam} package must
3693 be added to the @code{native-inputs} field of the package definition.
3695 Note that most OCaml packages assume they will be installed in the same
3696 directory as OCaml, which is not what we want in guix. In particular, they
3697 will install @file{.so} files in their module's directory, which is usually
3698 fine because it is in the OCaml compiler directory. In guix though, these
3699 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3700 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3701 @file{.so} libraries should be installed.
3704 @defvr {Scheme Variable} python-build-system
3705 This variable is exported by @code{(guix build-system python)}. It
3706 implements the more or less standard build procedure used by Python
3707 packages, which consists in running @code{python setup.py build} and
3708 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3710 For packages that install stand-alone Python programs under @code{bin/},
3711 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3712 environment variable points to all the Python libraries they depend on.
3714 Which Python package is used to perform the build can be specified with
3715 the @code{#:python} parameter. This is a useful way to force a package
3716 to be built for a specific version of the Python interpreter, which
3717 might be necessary if the package is only compatible with a single
3718 interpreter version.
3720 By default guix calls @code{setup.py} under control of
3721 @code{setuptools}, much like @command{pip} does. Some packages are not
3722 compatible with setuptools (and pip), thus you can disable this by
3723 setting the @code{#:use-setuptools} parameter to @code{#f}.
3726 @defvr {Scheme Variable} perl-build-system
3727 This variable is exported by @code{(guix build-system perl)}. It
3728 implements the standard build procedure for Perl packages, which either
3729 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3730 followed by @code{Build} and @code{Build install}; or in running
3731 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3732 @code{make} and @code{make install}, depending on which of
3733 @code{Build.PL} or @code{Makefile.PL} is present in the package
3734 distribution. Preference is given to the former if both @code{Build.PL}
3735 and @code{Makefile.PL} exist in the package distribution. This
3736 preference can be reversed by specifying @code{#t} for the
3737 @code{#:make-maker?} parameter.
3739 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3740 passes flags specified by the @code{#:make-maker-flags} or
3741 @code{#:module-build-flags} parameter, respectively.
3743 Which Perl package is used can be specified with @code{#:perl}.
3746 @defvr {Scheme Variable} r-build-system
3747 This variable is exported by @code{(guix build-system r)}. It
3748 implements the build procedure used by @uref{http://r-project.org, R}
3749 packages, which essentially is little more than running @code{R CMD
3750 INSTALL --library=/gnu/store/@dots{}} in an environment where
3751 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3752 are run after installation using the R function
3753 @code{tools::testInstalledPackage}.
3756 @defvr {Scheme Variable} texlive-build-system
3757 This variable is exported by @code{(guix build-system texlive)}. It is
3758 used to build TeX packages in batch mode with a specified engine. The
3759 build system sets the @code{TEXINPUTS} variable to find all TeX source
3760 files in the inputs.
3762 By default it runs @code{luatex} on all files ending on @code{ins}. A
3763 different engine and format can be specified with the
3764 @code{#:tex-format} argument. Different build targets can be specified
3765 with the @code{#:build-targets} argument, which expects a list of file
3766 names. The build system adds only @code{texlive-bin} and
3767 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3768 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3769 and @code{#:texlive-latex-base}, respectively.
3771 The @code{#:tex-directory} parameter tells the build system where to
3772 install the built files under the texmf tree.
3775 @defvr {Scheme Variable} ruby-build-system
3776 This variable is exported by @code{(guix build-system ruby)}. It
3777 implements the RubyGems build procedure used by Ruby packages, which
3778 involves running @code{gem build} followed by @code{gem install}.
3780 The @code{source} field of a package that uses this build system
3781 typically references a gem archive, since this is the format that Ruby
3782 developers use when releasing their software. The build system unpacks
3783 the gem archive, potentially patches the source, runs the test suite,
3784 repackages the gem, and installs it. Additionally, directories and
3785 tarballs may be referenced to allow building unreleased gems from Git or
3786 a traditional source release tarball.
3788 Which Ruby package is used can be specified with the @code{#:ruby}
3789 parameter. A list of additional flags to be passed to the @command{gem}
3790 command can be specified with the @code{#:gem-flags} parameter.
3793 @defvr {Scheme Variable} waf-build-system
3794 This variable is exported by @code{(guix build-system waf)}. It
3795 implements a build procedure around the @code{waf} script. The common
3796 phases---@code{configure}, @code{build}, and @code{install}---are
3797 implemented by passing their names as arguments to the @code{waf}
3800 The @code{waf} script is executed by the Python interpreter. Which
3801 Python package is used to run the script can be specified with the
3802 @code{#:python} parameter.
3805 @defvr {Scheme Variable} haskell-build-system
3806 This variable is exported by @code{(guix build-system haskell)}. It
3807 implements the Cabal build procedure used by Haskell packages, which
3808 involves running @code{runhaskell Setup.hs configure
3809 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3810 Instead of installing the package by running @code{runhaskell Setup.hs
3811 install}, to avoid trying to register libraries in the read-only
3812 compiler store directory, the build system uses @code{runhaskell
3813 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3814 addition, the build system generates the package documentation by
3815 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3816 is passed. Optional Haddock parameters can be passed with the help of
3817 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3818 not found, the build system looks for @code{Setup.lhs} instead.
3820 Which Haskell compiler is used can be specified with the @code{#:haskell}
3821 parameter which defaults to @code{ghc}.
3824 @defvr {Scheme Variable} dub-build-system
3825 This variable is exported by @code{(guix build-system dub)}. It
3826 implements the Dub build procedure used by D packages, which
3827 involves running @code{dub build} and @code{dub run}.
3828 Installation is done by copying the files manually.
3830 Which D compiler is used can be specified with the @code{#:ldc}
3831 parameter which defaults to @code{ldc}.
3834 @defvr {Scheme Variable} emacs-build-system
3835 This variable is exported by @code{(guix build-system emacs)}. It
3836 implements an installation procedure similar to the packaging system
3837 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3839 It first creates the @code{@var{package}-autoloads.el} file, then it
3840 byte compiles all Emacs Lisp files. Differently from the Emacs
3841 packaging system, the Info documentation files are moved to the standard
3842 documentation directory and the @file{dir} file is deleted. Each
3843 package is installed in its own directory under
3844 @file{share/emacs/site-lisp/guix.d}.
3847 @defvr {Scheme Variable} font-build-system
3848 This variable is exported by @code{(guix build-system font)}. It
3849 implements an installation procedure for font packages where upstream
3850 provides pre-compiled TrueType, OpenType, etc. font files that merely
3851 need to be copied into place. It copies font files to standard
3852 locations in the output directory.
3855 @defvr {Scheme Variable} meson-build-system
3856 This variable is exported by @code{(guix build-system meson)}. It
3857 implements the build procedure for packages that use
3858 @url{http://mesonbuild.com, Meson} as their build system.
3860 It adds both Meson and @uref{https://ninja-build.org/, Ninja} to the set
3861 of inputs, and they can be changed with the parameters @code{#:meson}
3862 and @code{#:ninja} if needed. The default Meson is
3863 @code{meson-for-build}, which is special because it doesn't clear the
3864 @code{RUNPATH} of binaries and libraries when they are installed.
3866 This build system is an extension of @var{gnu-build-system}, but with the
3867 following phases changed to some specific for Meson:
3872 The phase runs @code{meson} with the flags specified in
3873 @code{#:configure-flags}. The flag @code{--build-type} is always set to
3874 @code{plain} unless something else is specified in @code{#:build-type}.
3877 The phase runs @code{ninja} to build the package in parallel by default, but
3878 this can be changed with @code{#:parallel-build?}.
3881 The phase runs @code{ninja} with the target specified in @code{#:test-target},
3882 which is @code{"test"} by default.
3885 The phase runs @code{ninja install} and can not be changed.
3888 Apart from that, the build system also adds the following phases:
3893 This phase tries to locate the local directories in the package being build,
3894 which has libraries that some of the binaries need. If any are found, they will
3895 be added to the programs @code{RUNPATH}. It is needed because
3896 @code{meson-for-build} keeps the @code{RUNPATH} of binaries and libraries from
3897 when they are build, but often that is not the @code{RUNPATH} we want.
3898 Therefor it is also shrinked to the minimum needed by the program.
3900 @item glib-or-gtk-wrap
3901 This phase is the phase provided by @code{glib-or-gtk-build-system}, and it
3902 is not enabled by default. It can be enabled with @code{#:glib-or-gtk?}.
3904 @item glib-or-gtk-compile-schemas
3905 This phase is the phase provided by @code{glib-or-gtk-build-system}, and it
3906 is not enabled by default. It can be enabled with @code{#:glib-or-gtk?}.
3910 Lastly, for packages that do not need anything as sophisticated, a
3911 ``trivial'' build system is provided. It is trivial in the sense that
3912 it provides basically no support: it does not pull any implicit inputs,
3913 and does not have a notion of build phases.
3915 @defvr {Scheme Variable} trivial-build-system
3916 This variable is exported by @code{(guix build-system trivial)}.
3918 This build system requires a @code{#:builder} argument. This argument
3919 must be a Scheme expression that builds the package output(s)---as
3920 with @code{build-expression->derivation} (@pxref{Derivations,
3921 @code{build-expression->derivation}}).
3931 Conceptually, the @dfn{store} is the place where derivations that have
3932 been built successfully are stored---by default, @file{/gnu/store}.
3933 Sub-directories in the store are referred to as @dfn{store items} or
3934 sometimes @dfn{store paths}. The store has an associated database that
3935 contains information such as the store paths referred to by each store
3936 path, and the list of @emph{valid} store items---results of successful
3937 builds. This database resides in @file{@var{localstatedir}/guix/db},
3938 where @var{localstatedir} is the state directory specified @i{via}
3939 @option{--localstatedir} at configure time, usually @file{/var}.
3941 The store is @emph{always} accessed by the daemon on behalf of its clients
3942 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3943 connect to the daemon over a Unix-domain socket, send requests to it,
3944 and read the result---these are remote procedure calls, or RPCs.
3947 Users must @emph{never} modify files under @file{/gnu/store} directly.
3948 This would lead to inconsistencies and break the immutability
3949 assumptions of Guix's functional model (@pxref{Introduction}).
3951 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3952 how to check the integrity of the store and attempt recovery from
3953 accidental modifications.
3956 The @code{(guix store)} module provides procedures to connect to the
3957 daemon, and to perform RPCs. These are described below. By default,
3958 @code{open-connection}, and thus all the @command{guix} commands,
3959 connect to the local daemon or to the URI specified by the
3960 @code{GUIX_DAEMON_SOCKET} environment variable.
3962 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3963 When set, the value of this variable should be a file name or a URI
3964 designating the daemon endpoint. When it is a file name, it denotes a
3965 Unix-domain socket to connect to. In addition to file names, the
3966 supported URI schemes are:
3971 These are for Unix-domain sockets.
3972 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3973 @file{/var/guix/daemon-socket/socket}.
3976 @cindex daemon, remote access
3977 @cindex remote access to the daemon
3978 @cindex daemon, cluster setup
3979 @cindex clusters, daemon setup
3980 These URIs denote connections over TCP/IP, without encryption nor
3981 authentication of the remote host. The URI must specify the host name
3982 and optionally a port number (by default port 44146 is used):
3985 guix://master.guix.example.org:1234
3988 This setup is suitable on local networks, such as clusters, where only
3989 trusted nodes may connect to the build daemon at
3990 @code{master.guix.example.org}.
3992 The @code{--listen} option of @command{guix-daemon} can be used to
3993 instruct it to listen for TCP connections (@pxref{Invoking guix-daemon,
3997 @cindex SSH access to build daemons
3998 These URIs allow you to connect to a remote daemon over
3999 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
4000 A typical URL might look like this:
4003 ssh://charlie@@guix.example.org:22
4006 As for @command{guix copy}, the usual OpenSSH client configuration files
4007 are honored (@pxref{Invoking guix copy}).
4010 Additional URI schemes may be supported in the future.
4012 @c XXX: Remove this note when the protocol incurs fewer round trips
4013 @c and when (guix derivations) no longer relies on file system access.
4015 The ability to connect to remote build daemons is considered
4016 experimental as of @value{VERSION}. Please get in touch with us to
4017 share any problems or suggestions you may have (@pxref{Contributing}).
4021 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
4022 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
4023 @var{reserve-space?} is true, instruct it to reserve a little bit of
4024 extra space on the file system so that the garbage collector can still
4025 operate should the disk become full. Return a server object.
4027 @var{file} defaults to @var{%default-socket-path}, which is the normal
4028 location given the options that were passed to @command{configure}.
4031 @deffn {Scheme Procedure} close-connection @var{server}
4032 Close the connection to @var{server}.
4035 @defvr {Scheme Variable} current-build-output-port
4036 This variable is bound to a SRFI-39 parameter, which refers to the port
4037 where build and error logs sent by the daemon should be written.
4040 Procedures that make RPCs all take a server object as their first
4043 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
4044 @cindex invalid store items
4045 Return @code{#t} when @var{path} designates a valid store item and
4046 @code{#f} otherwise (an invalid item may exist on disk but still be
4047 invalid, for instance because it is the result of an aborted or failed
4050 A @code{&nix-protocol-error} condition is raised if @var{path} is not
4051 prefixed by the store directory (@file{/gnu/store}).
4054 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
4055 Add @var{text} under file @var{name} in the store, and return its store
4056 path. @var{references} is the list of store paths referred to by the
4057 resulting store path.
4060 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
4061 Build @var{derivations} (a list of @code{<derivation>} objects or
4062 derivation paths), and return when the worker is done building them.
4063 Return @code{#t} on success.
4066 Note that the @code{(guix monads)} module provides a monad as well as
4067 monadic versions of the above procedures, with the goal of making it
4068 more convenient to work with code that accesses the store (@pxref{The
4072 @i{This section is currently incomplete.}
4075 @section Derivations
4078 Low-level build actions and the environment in which they are performed
4079 are represented by @dfn{derivations}. A derivation contains the
4080 following pieces of information:
4084 The outputs of the derivation---derivations produce at least one file or
4085 directory in the store, but may produce more.
4088 The inputs of the derivations, which may be other derivations or plain
4089 files in the store (patches, build scripts, etc.)
4092 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
4095 The file name of a build script in the store, along with the arguments
4099 A list of environment variables to be defined.
4103 @cindex derivation path
4104 Derivations allow clients of the daemon to communicate build actions to
4105 the store. They exist in two forms: as an in-memory representation,
4106 both on the client- and daemon-side, and as files in the store whose
4107 name end in @code{.drv}---these files are referred to as @dfn{derivation
4108 paths}. Derivations paths can be passed to the @code{build-derivations}
4109 procedure to perform the build actions they prescribe (@pxref{The
4112 The @code{(guix derivations)} module provides a representation of
4113 derivations as Scheme objects, along with procedures to create and
4114 otherwise manipulate derivations. The lowest-level primitive to create
4115 a derivation is the @code{derivation} procedure:
4117 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
4118 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4119 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
4120 [#:system (%current-system)] [#:references-graphs #f] @
4121 [#:allowed-references #f] [#:disallowed-references #f] @
4122 [#:leaked-env-vars #f] [#:local-build? #f] @
4123 [#:substitutable? #t]
4124 Build a derivation with the given arguments, and return the resulting
4125 @code{<derivation>} object.
4127 When @var{hash} and @var{hash-algo} are given, a
4128 @dfn{fixed-output derivation} is created---i.e., one whose result is
4129 known in advance, such as a file download. If, in addition,
4130 @var{recursive?} is true, then that fixed output may be an executable
4131 file or a directory and @var{hash} must be the hash of an archive
4132 containing this output.
4134 When @var{references-graphs} is true, it must be a list of file
4135 name/store path pairs. In that case, the reference graph of each store
4136 path is exported in the build environment in the corresponding file, in
4137 a simple text format.
4139 When @var{allowed-references} is true, it must be a list of store items
4140 or outputs that the derivation's output may refer to. Likewise,
4141 @var{disallowed-references}, if true, must be a list of things the
4142 outputs may @emph{not} refer to.
4144 When @var{leaked-env-vars} is true, it must be a list of strings
4145 denoting environment variables that are allowed to ``leak'' from the
4146 daemon's environment to the build environment. This is only applicable
4147 to fixed-output derivations---i.e., when @var{hash} is true. The main
4148 use is to allow variables such as @code{http_proxy} to be passed to
4149 derivations that download files.
4151 When @var{local-build?} is true, declare that the derivation is not a
4152 good candidate for offloading and should rather be built locally
4153 (@pxref{Daemon Offload Setup}). This is the case for small derivations
4154 where the costs of data transfers would outweigh the benefits.
4156 When @var{substitutable?} is false, declare that substitutes of the
4157 derivation's output should not be used (@pxref{Substitutes}). This is
4158 useful, for instance, when building packages that capture details of the
4159 host CPU instruction set.
4163 Here's an example with a shell script as its builder, assuming
4164 @var{store} is an open connection to the daemon, and @var{bash} points
4165 to a Bash executable in the store:
4168 (use-modules (guix utils)
4172 (let ((builder ; add the Bash script to the store
4173 (add-text-to-store store "my-builder.sh"
4174 "echo hello world > $out\n" '())))
4175 (derivation store "foo"
4176 bash `("-e" ,builder)
4177 #:inputs `((,bash) (,builder))
4178 #:env-vars '(("HOME" . "/homeless"))))
4179 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
4182 As can be guessed, this primitive is cumbersome to use directly. A
4183 better approach is to write build scripts in Scheme, of course! The
4184 best course of action for that is to write the build code as a
4185 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
4186 information, @pxref{G-Expressions}.
4188 Once upon a time, @code{gexp->derivation} did not exist and constructing
4189 derivations with build code written in Scheme was achieved with
4190 @code{build-expression->derivation}, documented below. This procedure
4191 is now deprecated in favor of the much nicer @code{gexp->derivation}.
4193 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
4194 @var{name} @var{exp} @
4195 [#:system (%current-system)] [#:inputs '()] @
4196 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4197 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4198 [#:references-graphs #f] [#:allowed-references #f] @
4199 [#:disallowed-references #f] @
4200 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4201 Return a derivation that executes Scheme expression @var{exp} as a
4202 builder for derivation @var{name}. @var{inputs} must be a list of
4203 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
4204 @code{"out"} is assumed. @var{modules} is a list of names of Guile
4205 modules from the current search path to be copied in the store,
4206 compiled, and made available in the load path during the execution of
4207 @var{exp}---e.g., @code{((guix build utils) (guix build
4208 gnu-build-system))}.
4210 @var{exp} is evaluated in an environment where @code{%outputs} is bound
4211 to a list of output/path pairs, and where @code{%build-inputs} is bound
4212 to a list of string/output-path pairs made from @var{inputs}.
4213 Optionally, @var{env-vars} is a list of string pairs specifying the name
4214 and value of environment variables visible to the builder. The builder
4215 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4216 @var{exp} returns @code{#f}, the build is considered to have failed.
4218 @var{exp} is built using @var{guile-for-build} (a derivation). When
4219 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4220 @code{%guile-for-build} fluid is used instead.
4222 See the @code{derivation} procedure for the meaning of
4223 @var{references-graphs}, @var{allowed-references},
4224 @var{disallowed-references}, @var{local-build?}, and
4225 @var{substitutable?}.
4229 Here's an example of a single-output derivation that creates a directory
4230 containing one file:
4233 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4234 (mkdir out) ; create /gnu/store/@dots{}-goo
4235 (call-with-output-file (string-append out "/test")
4237 (display '(hello guix) p))))))
4238 (build-expression->derivation store "goo" builder))
4240 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4244 @node The Store Monad
4245 @section The Store Monad
4249 The procedures that operate on the store described in the previous
4250 sections all take an open connection to the build daemon as their first
4251 argument. Although the underlying model is functional, they either have
4252 side effects or depend on the current state of the store.
4254 The former is inconvenient: the connection to the build daemon has to be
4255 carried around in all those functions, making it impossible to compose
4256 functions that do not take that parameter with functions that do. The
4257 latter can be problematic: since store operations have side effects
4258 and/or depend on external state, they have to be properly sequenced.
4260 @cindex monadic values
4261 @cindex monadic functions
4262 This is where the @code{(guix monads)} module comes in. This module
4263 provides a framework for working with @dfn{monads}, and a particularly
4264 useful monad for our uses, the @dfn{store monad}. Monads are a
4265 construct that allows two things: associating ``context'' with values
4266 (in our case, the context is the store), and building sequences of
4267 computations (here computations include accesses to the store). Values
4268 in a monad---values that carry this additional context---are called
4269 @dfn{monadic values}; procedures that return such values are called
4270 @dfn{monadic procedures}.
4272 Consider this ``normal'' procedure:
4275 (define (sh-symlink store)
4276 ;; Return a derivation that symlinks the 'bash' executable.
4277 (let* ((drv (package-derivation store bash))
4278 (out (derivation->output-path drv))
4279 (sh (string-append out "/bin/bash")))
4280 (build-expression->derivation store "sh"
4281 `(symlink ,sh %output))))
4284 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4285 as a monadic function:
4288 (define (sh-symlink)
4289 ;; Same, but return a monadic value.
4290 (mlet %store-monad ((drv (package->derivation bash)))
4291 (gexp->derivation "sh"
4292 #~(symlink (string-append #$drv "/bin/bash")
4296 There are several things to note in the second version: the @code{store}
4297 parameter is now implicit and is ``threaded'' in the calls to the
4298 @code{package->derivation} and @code{gexp->derivation} monadic
4299 procedures, and the monadic value returned by @code{package->derivation}
4300 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4302 As it turns out, the call to @code{package->derivation} can even be
4303 omitted since it will take place implicitly, as we will see later
4304 (@pxref{G-Expressions}):
4307 (define (sh-symlink)
4308 (gexp->derivation "sh"
4309 #~(symlink (string-append #$bash "/bin/bash")
4314 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4315 @c for the funny quote.
4316 Calling the monadic @code{sh-symlink} has no effect. As someone once
4317 said, ``you exit a monad like you exit a building on fire: by running''.
4318 So, to exit the monad and get the desired effect, one must use
4319 @code{run-with-store}:
4322 (run-with-store (open-connection) (sh-symlink))
4323 @result{} /gnu/store/...-sh-symlink
4326 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4327 new ``meta-commands'' to make it easier to deal with monadic procedures:
4328 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4329 to ``run'' a single monadic value through the store:
4332 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4333 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4336 The latter enters a recursive REPL, where all the return values are
4337 automatically run through the store:
4340 scheme@@(guile-user)> ,enter-store-monad
4341 store-monad@@(guile-user) [1]> (package->derivation hello)
4342 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4343 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4344 $3 = "/gnu/store/@dots{}-foo"
4345 store-monad@@(guile-user) [1]> ,q
4346 scheme@@(guile-user)>
4350 Note that non-monadic values cannot be returned in the
4351 @code{store-monad} REPL.
4353 The main syntactic forms to deal with monads in general are provided by
4354 the @code{(guix monads)} module and are described below.
4356 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4357 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4361 @deffn {Scheme Syntax} return @var{val}
4362 Return a monadic value that encapsulates @var{val}.
4365 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4366 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4367 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4368 referred to as ``bind'', but that name denotes an unrelated procedure in
4369 Guile. Thus we use this somewhat cryptic symbol inherited from the
4370 Haskell language.}. There can be one @var{mproc} or several of them, as
4375 (with-monad %state-monad
4377 (lambda (x) (return (+ 1 x)))
4378 (lambda (x) (return (* 2 x)))))
4382 @result{} some-state
4386 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4388 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4390 Bind the variables @var{var} to the monadic values @var{mval} in
4391 @var{body}, which is a sequence of expressions. As with the bind
4392 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4393 value ``contained'' in @var{mval} and making @var{var} refer to that
4394 raw, non-monadic value within the scope of the @var{body}. The form
4395 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4396 @var{val}, as per @code{let}. The binding operations occur in sequence
4397 from left to right. The last expression of @var{body} must be a monadic
4398 expression, and its result will become the result of the @code{mlet} or
4399 @code{mlet*} when run in the @var{monad}.
4401 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4402 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4405 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4406 Bind @var{mexp} and the following monadic expressions in sequence,
4407 returning the result of the last expression. Every expression in the
4408 sequence must be a monadic expression.
4410 This is akin to @code{mlet}, except that the return values of the
4411 monadic expressions are ignored. In that sense, it is analogous to
4412 @code{begin}, but applied to monadic expressions.
4415 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4416 When @var{condition} is true, evaluate the sequence of monadic
4417 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4418 @var{condition} is false, return @code{*unspecified*} in the current
4419 monad. Every expression in the sequence must be a monadic expression.
4422 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4423 When @var{condition} is false, evaluate the sequence of monadic
4424 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4425 @var{condition} is true, return @code{*unspecified*} in the current
4426 monad. Every expression in the sequence must be a monadic expression.
4430 The @code{(guix monads)} module provides the @dfn{state monad}, which
4431 allows an additional value---the state---to be @emph{threaded} through
4432 monadic procedure calls.
4434 @defvr {Scheme Variable} %state-monad
4435 The state monad. Procedures in the state monad can access and change
4436 the state that is threaded.
4438 Consider the example below. The @code{square} procedure returns a value
4439 in the state monad. It returns the square of its argument, but also
4440 increments the current state value:
4444 (mlet %state-monad ((count (current-state)))
4445 (mbegin %state-monad
4446 (set-current-state (+ 1 count))
4449 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4454 When ``run'' through @var{%state-monad}, we obtain that additional state
4455 value, which is the number of @code{square} calls.
4458 @deffn {Monadic Procedure} current-state
4459 Return the current state as a monadic value.
4462 @deffn {Monadic Procedure} set-current-state @var{value}
4463 Set the current state to @var{value} and return the previous state as a
4467 @deffn {Monadic Procedure} state-push @var{value}
4468 Push @var{value} to the current state, which is assumed to be a list,
4469 and return the previous state as a monadic value.
4472 @deffn {Monadic Procedure} state-pop
4473 Pop a value from the current state and return it as a monadic value.
4474 The state is assumed to be a list.
4477 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4478 Run monadic value @var{mval} starting with @var{state} as the initial
4479 state. Return two values: the resulting value, and the resulting state.
4482 The main interface to the store monad, provided by the @code{(guix
4483 store)} module, is as follows.
4485 @defvr {Scheme Variable} %store-monad
4486 The store monad---an alias for @var{%state-monad}.
4488 Values in the store monad encapsulate accesses to the store. When its
4489 effect is needed, a value of the store monad must be ``evaluated'' by
4490 passing it to the @code{run-with-store} procedure (see below.)
4493 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4494 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4495 open store connection.
4498 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4499 Return as a monadic value the absolute file name in the store of the file
4500 containing @var{text}, a string. @var{references} is a list of store items that the
4501 resulting text file refers to; it defaults to the empty list.
4504 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4505 [#:recursive? #t] [#:select? (const #t)]
4506 Return the name of @var{file} once interned in the store. Use
4507 @var{name} as its store name, or the basename of @var{file} if
4508 @var{name} is omitted.
4510 When @var{recursive?} is true, the contents of @var{file} are added
4511 recursively; if @var{file} designates a flat file and @var{recursive?}
4512 is true, its contents are added, and its permission bits are kept.
4514 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4515 @var{stat})} for each directory entry, where @var{file} is the entry's
4516 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4517 entries for which @var{select?} does not return true.
4519 The example below adds a file to the store, under two different names:
4522 (run-with-store (open-connection)
4523 (mlet %store-monad ((a (interned-file "README"))
4524 (b (interned-file "README" "LEGU-MIN")))
4525 (return (list a b))))
4527 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4532 The @code{(guix packages)} module exports the following package-related
4535 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4536 [#:system (%current-system)] [#:target #f] @
4539 value in the absolute file name of @var{file} within the @var{output}
4540 directory of @var{package}. When @var{file} is omitted, return the name
4541 of the @var{output} directory of @var{package}. When @var{target} is
4542 true, use it as a cross-compilation target triplet.
4545 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4546 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4547 @var{target} [@var{system}]
4548 Monadic version of @code{package-derivation} and
4549 @code{package-cross-derivation} (@pxref{Defining Packages}).
4554 @section G-Expressions
4556 @cindex G-expression
4557 @cindex build code quoting
4558 So we have ``derivations'', which represent a sequence of build actions
4559 to be performed to produce an item in the store (@pxref{Derivations}).
4560 These build actions are performed when asking the daemon to actually
4561 build the derivations; they are run by the daemon in a container
4562 (@pxref{Invoking guix-daemon}).
4564 @cindex strata of code
4565 It should come as no surprise that we like to write these build actions
4566 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4567 code@footnote{The term @dfn{stratum} in this context was coined by
4568 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4569 Kiselyov, who has written insightful
4570 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4571 on this topic}, refers to this kind of code generation as
4572 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4573 to the daemon, etc.---and the ``build code''---code that actually
4574 performs build actions, such as making directories, invoking
4575 @command{make}, etc.
4577 To describe a derivation and its build actions, one typically needs to
4578 embed build code inside host code. It boils down to manipulating build
4579 code as data, and the homoiconicity of Scheme---code has a direct
4580 representation as data---comes in handy for that. But we need more than
4581 the normal @code{quasiquote} mechanism in Scheme to construct build
4584 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4585 S-expressions adapted to build expressions. G-expressions, or
4586 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4587 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4588 @code{#$}, and @code{#$@@}), which are comparable to
4589 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4590 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4591 GNU Guile Reference Manual}). However, there are major differences:
4595 Gexps are meant to be written to a file and run or manipulated by other
4599 When a high-level object such as a package or derivation is unquoted
4600 inside a gexp, the result is as if its output file name had been
4604 Gexps carry information about the packages or derivations they refer to,
4605 and these dependencies are automatically added as inputs to the build
4606 processes that use them.
4609 @cindex lowering, of high-level objects in gexps
4610 This mechanism is not limited to package and derivation
4611 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4612 derivations or files in the store can be defined,
4613 such that these objects can also be inserted
4614 into gexps. For example, a useful type of high-level objects that can be
4615 inserted in a gexp is ``file-like objects'', which make it easy to
4616 add files to the store and to refer to them in
4617 derivations and such (see @code{local-file} and @code{plain-file}
4620 To illustrate the idea, here is an example of a gexp:
4627 (symlink (string-append #$coreutils "/bin/ls")
4631 This gexp can be passed to @code{gexp->derivation}; we obtain a
4632 derivation that builds a directory containing exactly one symlink to
4633 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4636 (gexp->derivation "the-thing" build-exp)
4639 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4640 substituted to the reference to the @var{coreutils} package in the
4641 actual build code, and @var{coreutils} is automatically made an input to
4642 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4643 output)}) is replaced by a string containing the directory name of the
4644 output of the derivation.
4646 @cindex cross compilation
4647 In a cross-compilation context, it is useful to distinguish between
4648 references to the @emph{native} build of a package---that can run on the
4649 host---versus references to cross builds of a package. To that end, the
4650 @code{#+} plays the same role as @code{#$}, but is a reference to a
4651 native package build:
4654 (gexp->derivation "vi"
4657 (system* (string-append #+coreutils "/bin/ln")
4659 (string-append #$emacs "/bin/emacs")
4660 (string-append #$output "/bin/vi")))
4661 #:target "mips64el-linux-gnu")
4665 In the example above, the native build of @var{coreutils} is used, so
4666 that @command{ln} can actually run on the host; but then the
4667 cross-compiled build of @var{emacs} is referenced.
4669 @cindex imported modules, for gexps
4670 @findex with-imported-modules
4671 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4672 able to use certain Guile modules from the ``host environment'' in the
4673 gexp, so those modules should be imported in the ``build environment''.
4674 The @code{with-imported-modules} form allows you to express that:
4677 (let ((build (with-imported-modules '((guix build utils))
4679 (use-modules (guix build utils))
4680 (mkdir-p (string-append #$output "/bin"))))))
4681 (gexp->derivation "empty-dir"
4684 (display "success!\n")
4689 In this example, the @code{(guix build utils)} module is automatically
4690 pulled into the isolated build environment of our gexp, such that
4691 @code{(use-modules (guix build utils))} works as expected.
4693 @cindex module closure
4694 @findex source-module-closure
4695 Usually you want the @emph{closure} of the module to be imported---i.e.,
4696 the module itself and all the modules it depends on---rather than just
4697 the module; failing to do that, attempts to use the module will fail
4698 because of missing dependent modules. The @code{source-module-closure}
4699 procedure computes the closure of a module by looking at its source file
4700 headers, which comes in handy in this case:
4703 (use-modules (guix modules)) ;for 'source-module-closure'
4705 (with-imported-modules (source-module-closure
4706 '((guix build utils)
4708 (gexp->derivation "something-with-vms"
4710 (use-modules (guix build utils)
4715 The syntactic form to construct gexps is summarized below.
4717 @deffn {Scheme Syntax} #~@var{exp}
4718 @deffnx {Scheme Syntax} (gexp @var{exp})
4719 Return a G-expression containing @var{exp}. @var{exp} may contain one
4720 or more of the following forms:
4724 @itemx (ungexp @var{obj})
4725 Introduce a reference to @var{obj}. @var{obj} may have one of the
4726 supported types, for example a package or a
4727 derivation, in which case the @code{ungexp} form is replaced by its
4728 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4730 If @var{obj} is a list, it is traversed and references to supported
4731 objects are substituted similarly.
4733 If @var{obj} is another gexp, its contents are inserted and its
4734 dependencies are added to those of the containing gexp.
4736 If @var{obj} is another kind of object, it is inserted as is.
4738 @item #$@var{obj}:@var{output}
4739 @itemx (ungexp @var{obj} @var{output})
4740 This is like the form above, but referring explicitly to the
4741 @var{output} of @var{obj}---this is useful when @var{obj} produces
4742 multiple outputs (@pxref{Packages with Multiple Outputs}).
4745 @itemx #+@var{obj}:output
4746 @itemx (ungexp-native @var{obj})
4747 @itemx (ungexp-native @var{obj} @var{output})
4748 Same as @code{ungexp}, but produces a reference to the @emph{native}
4749 build of @var{obj} when used in a cross compilation context.
4751 @item #$output[:@var{output}]
4752 @itemx (ungexp output [@var{output}])
4753 Insert a reference to derivation output @var{output}, or to the main
4754 output when @var{output} is omitted.
4756 This only makes sense for gexps passed to @code{gexp->derivation}.
4759 @itemx (ungexp-splicing @var{lst})
4760 Like the above, but splices the contents of @var{lst} inside the
4764 @itemx (ungexp-native-splicing @var{lst})
4765 Like the above, but refers to native builds of the objects listed in
4770 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4771 of the @code{gexp?} type (see below.)
4774 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4775 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4776 in their execution environment.
4778 Each item in @var{modules} can be the name of a module, such as
4779 @code{(guix build utils)}, or it can be a module name, followed by an
4780 arrow, followed by a file-like object:
4783 `((guix build utils)
4785 ((guix config) => ,(scheme-file "config.scm"
4786 #~(define-module @dots{}))))
4790 In the example above, the first two modules are taken from the search
4791 path, and the last one is created from the given file-like object.
4793 This form has @emph{lexical} scope: it has an effect on the gexps
4794 directly defined in @var{body}@dots{}, but not on those defined, say, in
4795 procedures called from @var{body}@dots{}.
4798 @deffn {Scheme Procedure} gexp? @var{obj}
4799 Return @code{#t} if @var{obj} is a G-expression.
4802 G-expressions are meant to be written to disk, either as code building
4803 some derivation, or as plain files in the store. The monadic procedures
4804 below allow you to do that (@pxref{The Store Monad}, for more
4805 information about monads.)
4807 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4808 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4809 [#:hash #f] [#:hash-algo #f] @
4810 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4811 [#:module-path @var{%load-path}] @
4812 [#:references-graphs #f] [#:allowed-references #f] @
4813 [#:disallowed-references #f] @
4814 [#:leaked-env-vars #f] @
4815 [#:script-name (string-append @var{name} "-builder")] @
4816 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4817 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4818 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4819 stored in a file called @var{script-name}. When @var{target} is true,
4820 it is used as the cross-compilation target triplet for packages referred
4823 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4825 make @var{modules} available in the evaluation context of @var{exp};
4826 @var{modules} is a list of names of Guile modules searched in
4827 @var{module-path} to be copied in the store, compiled, and made available in
4828 the load path during the execution of @var{exp}---e.g., @code{((guix
4829 build utils) (guix build gnu-build-system))}.
4831 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4834 When @var{references-graphs} is true, it must be a list of tuples of one of the
4838 (@var{file-name} @var{package})
4839 (@var{file-name} @var{package} @var{output})
4840 (@var{file-name} @var{derivation})
4841 (@var{file-name} @var{derivation} @var{output})
4842 (@var{file-name} @var{store-item})
4845 The right-hand-side of each element of @var{references-graphs} is automatically made
4846 an input of the build process of @var{exp}. In the build environment, each
4847 @var{file-name} contains the reference graph of the corresponding item, in a simple
4850 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4851 In the latter case, the list denotes store items that the result is allowed to
4852 refer to. Any reference to another store item will lead to a build error.
4853 Similarly for @var{disallowed-references}, which can list items that must not be
4854 referenced by the outputs.
4856 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4859 @cindex file-like objects
4860 The @code{local-file}, @code{plain-file}, @code{computed-file},
4861 @code{program-file}, and @code{scheme-file} procedures below return
4862 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4863 these objects lead to a file in the store. Consider this G-expression:
4866 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4867 #$(local-file "/tmp/my-nscd.conf"))
4870 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4871 to the store. Once expanded, for instance @i{via}
4872 @code{gexp->derivation}, the G-expression refers to that copy under
4873 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4874 does not have any effect on what the G-expression does.
4875 @code{plain-file} can be used similarly; it differs in that the file
4876 content is directly passed as a string.
4878 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4879 [#:recursive? #f] [#:select? (const #t)]
4880 Return an object representing local file @var{file} to add to the store; this
4881 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4882 up relative to the source file where this form appears. @var{file} will be added to
4883 the store under @var{name}--by default the base name of @var{file}.
4885 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4886 designates a flat file and @var{recursive?} is true, its contents are added, and its
4887 permission bits are kept.
4889 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4890 @var{stat})} for each directory entry, where @var{file} is the entry's
4891 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4892 entries for which @var{select?} does not return true.
4894 This is the declarative counterpart of the @code{interned-file} monadic
4895 procedure (@pxref{The Store Monad, @code{interned-file}}).
4898 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4899 Return an object representing a text file called @var{name} with the given
4900 @var{content} (a string) to be added to the store.
4902 This is the declarative counterpart of @code{text-file}.
4905 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4906 [#:options '(#:local-build? #t)]
4907 Return an object representing the store item @var{name}, a file or
4908 directory computed by @var{gexp}. @var{options}
4909 is a list of additional arguments to pass to @code{gexp->derivation}.
4911 This is the declarative counterpart of @code{gexp->derivation}.
4914 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4915 Return an executable script @var{name} that runs @var{exp} using
4916 @var{guile}, with @var{exp}'s imported modules in its search path.
4918 The example below builds a script that simply invokes the @command{ls}
4922 (use-modules (guix gexp) (gnu packages base))
4924 (gexp->script "list-files"
4925 #~(execl #$(file-append coreutils "/bin/ls")
4929 When ``running'' it through the store (@pxref{The Store Monad,
4930 @code{run-with-store}}), we obtain a derivation that produces an
4931 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4934 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4936 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4940 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4942 Return an object representing the executable store item @var{name} that
4943 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4946 This is the declarative counterpart of @code{gexp->script}.
4949 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4950 [#:set-load-path? #t]
4951 Return a derivation that builds a file @var{name} containing @var{exp}.
4952 When @var{set-load-path?} is true, emit code in the resulting file to
4953 set @code{%load-path} and @code{%load-compiled-path} to honor
4954 @var{exp}'s imported modules.
4956 The resulting file holds references to all the dependencies of @var{exp}
4957 or a subset thereof.
4960 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4961 Return an object representing the Scheme file @var{name} that contains
4964 This is the declarative counterpart of @code{gexp->file}.
4967 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4968 Return as a monadic value a derivation that builds a text file
4969 containing all of @var{text}. @var{text} may list, in addition to
4970 strings, objects of any type that can be used in a gexp: packages,
4971 derivations, local file objects, etc. The resulting store file holds
4972 references to all these.
4974 This variant should be preferred over @code{text-file} anytime the file
4975 to create will reference items from the store. This is typically the
4976 case when building a configuration file that embeds store file names,
4980 (define (profile.sh)
4981 ;; Return the name of a shell script in the store that
4982 ;; initializes the 'PATH' environment variable.
4983 (text-file* "profile.sh"
4984 "export PATH=" coreutils "/bin:"
4985 grep "/bin:" sed "/bin\n"))
4988 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4989 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4990 preventing them from being garbage-collected during its lifetime.
4993 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4994 Return an object representing store file @var{name} containing
4995 @var{text}. @var{text} is a sequence of strings and file-like objects,
4999 (mixed-text-file "profile"
5000 "export PATH=" coreutils "/bin:" grep "/bin")
5003 This is the declarative counterpart of @code{text-file*}.
5006 @deffn {Scheme Procedure} file-union @var{name} @var{files}
5007 Return a @code{<computed-file>} that builds a directory containing all of @var{files}.
5008 Each item in @var{files} must be a two-element list where the first element is the
5009 file name to use in the new directory, and the second element is a gexp
5010 denoting the target file. Here's an example:
5014 `(("hosts" ,(plain-file "hosts"
5015 "127.0.0.1 localhost"))
5016 ("bashrc" ,(plain-file "bashrc"
5017 "alias ls='ls --color'"))))
5020 This yields an @code{etc} directory containing these two files.
5023 @deffn {Scheme Procedure} directory-union @var{name} @var{things}
5024 Return a directory that is the union of @var{things}, where @var{things} is a list of
5025 file-like objects denoting directories. For example:
5028 (directory-union "guile+emacs" (list guile emacs))
5031 yields a directory that is the union of the @code{guile} and @code{emacs} packages.
5034 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
5035 Return a file-like object that expands to the concatenation of @var{obj}
5036 and @var{suffix}, where @var{obj} is a lowerable object and each
5037 @var{suffix} is a string.
5039 As an example, consider this gexp:
5042 (gexp->script "run-uname"
5043 #~(system* #$(file-append coreutils
5047 The same effect could be achieved with:
5050 (gexp->script "run-uname"
5051 #~(system* (string-append #$coreutils
5055 There is one difference though: in the @code{file-append} case, the
5056 resulting script contains the absolute file name as a string, whereas in
5057 the second case, the resulting script contains a @code{(string-append
5058 @dots{})} expression to construct the file name @emph{at run time}.
5062 Of course, in addition to gexps embedded in ``host'' code, there are
5063 also modules containing build tools. To make it clear that they are
5064 meant to be used in the build stratum, these modules are kept in the
5065 @code{(guix build @dots{})} name space.
5067 @cindex lowering, of high-level objects in gexps
5068 Internally, high-level objects are @dfn{lowered}, using their compiler,
5069 to either derivations or store items. For instance, lowering a package
5070 yields a derivation, and lowering a @code{plain-file} yields a store
5071 item. This is achieved using the @code{lower-object} monadic procedure.
5073 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
5075 Return as a value in @var{%store-monad} the derivation or store item
5076 corresponding to @var{obj} for @var{system}, cross-compiling for
5077 @var{target} if @var{target} is true. @var{obj} must be an object that
5078 has an associated gexp compiler, such as a @code{<package>}.
5082 @c *********************************************************************
5086 This section describes Guix command-line utilities. Some of them are
5087 primarily targeted at developers and users who write new package
5088 definitions, while others are more generally useful. They complement
5089 the Scheme programming interface of Guix in a convenient way.
5092 * Invoking guix build:: Building packages from the command line.
5093 * Invoking guix edit:: Editing package definitions.
5094 * Invoking guix download:: Downloading a file and printing its hash.
5095 * Invoking guix hash:: Computing the cryptographic hash of a file.
5096 * Invoking guix import:: Importing package definitions.
5097 * Invoking guix refresh:: Updating package definitions.
5098 * Invoking guix lint:: Finding errors in package definitions.
5099 * Invoking guix size:: Profiling disk usage.
5100 * Invoking guix graph:: Visualizing the graph of packages.
5101 * Invoking guix environment:: Setting up development environments.
5102 * Invoking guix publish:: Sharing substitutes.
5103 * Invoking guix challenge:: Challenging substitute servers.
5104 * Invoking guix copy:: Copying to and from a remote store.
5105 * Invoking guix container:: Process isolation.
5106 * Invoking guix weather:: Assessing substitute availability.
5109 @node Invoking guix build
5110 @section Invoking @command{guix build}
5112 @cindex package building
5113 @cindex @command{guix build}
5114 The @command{guix build} command builds packages or derivations and
5115 their dependencies, and prints the resulting store paths. Note that it
5116 does not modify the user's profile---this is the job of the
5117 @command{guix package} command (@pxref{Invoking guix package}). Thus,
5118 it is mainly useful for distribution developers.
5120 The general syntax is:
5123 guix build @var{options} @var{package-or-derivation}@dots{}
5126 As an example, the following command builds the latest versions of Emacs
5127 and of Guile, displays their build logs, and finally displays the
5128 resulting directories:
5131 guix build emacs guile
5134 Similarly, the following command builds all the available packages:
5137 guix build --quiet --keep-going \
5138 `guix package -A | cut -f1,2 --output-delimiter=@@`
5141 @var{package-or-derivation} may be either the name of a package found in
5142 the software distribution such as @code{coreutils} or
5143 @code{coreutils@@8.20}, or a derivation such as
5144 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
5145 package with the corresponding name (and optionally version) is searched
5146 for among the GNU distribution modules (@pxref{Package Modules}).
5148 Alternatively, the @code{--expression} option may be used to specify a
5149 Scheme expression that evaluates to a package; this is useful when
5150 disambiguating among several same-named packages or package variants is
5153 There may be zero or more @var{options}. The available options are
5154 described in the subsections below.
5157 * Common Build Options:: Build options for most commands.
5158 * Package Transformation Options:: Creating variants of packages.
5159 * Additional Build Options:: Options specific to 'guix build'.
5160 * Debugging Build Failures:: Real life packaging experience.
5163 @node Common Build Options
5164 @subsection Common Build Options
5166 A number of options that control the build process are common to
5167 @command{guix build} and other commands that can spawn builds, such as
5168 @command{guix package} or @command{guix archive}. These are the
5173 @item --load-path=@var{directory}
5174 @itemx -L @var{directory}
5175 Add @var{directory} to the front of the package module search path
5176 (@pxref{Package Modules}).
5178 This allows users to define their own packages and make them visible to
5179 the command-line tools.
5183 Keep the build tree of failed builds. Thus, if a build fails, its build
5184 tree is kept under @file{/tmp}, in a directory whose name is shown at
5185 the end of the build log. This is useful when debugging build issues.
5186 @xref{Debugging Build Failures}, for tips and tricks on how to debug
5191 Keep going when some of the derivations fail to build; return only once
5192 all the builds have either completed or failed.
5194 The default behavior is to stop as soon as one of the specified
5195 derivations has failed.
5199 Do not build the derivations.
5202 When substituting a pre-built binary fails, fall back to building
5205 @item --substitute-urls=@var{urls}
5206 @anchor{client-substitute-urls}
5207 Consider @var{urls} the whitespace-separated list of substitute source
5208 URLs, overriding the default list of URLs of @command{guix-daemon}
5209 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
5211 This means that substitutes may be downloaded from @var{urls}, provided
5212 they are signed by a key authorized by the system administrator
5213 (@pxref{Substitutes}).
5215 When @var{urls} is the empty string, substitutes are effectively
5218 @item --no-substitutes
5219 Do not use substitutes for build products. That is, always build things
5220 locally instead of allowing downloads of pre-built binaries
5221 (@pxref{Substitutes}).
5224 Do not ``graft'' packages. In practice, this means that package updates
5225 available as grafts are not applied. @xref{Security Updates}, for more
5226 information on grafts.
5228 @item --rounds=@var{n}
5229 Build each derivation @var{n} times in a row, and raise an error if
5230 consecutive build results are not bit-for-bit identical.
5232 This is a useful way to detect non-deterministic builds processes.
5233 Non-deterministic build processes are a problem because they make it
5234 practically impossible for users to @emph{verify} whether third-party
5235 binaries are genuine. @xref{Invoking guix challenge}, for more.
5237 Note that, currently, the differing build results are not kept around,
5238 so you will have to manually investigate in case of an error---e.g., by
5239 stashing one of the build results with @code{guix archive --export}
5240 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5243 @item --no-build-hook
5244 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5245 (@pxref{Daemon Offload Setup}). That is, always build things locally
5246 instead of offloading builds to remote machines.
5248 @item --max-silent-time=@var{seconds}
5249 When the build or substitution process remains silent for more than
5250 @var{seconds}, terminate it and report a build failure.
5252 By default, the daemon's setting is honored (@pxref{Invoking
5253 guix-daemon, @code{--max-silent-time}}).
5255 @item --timeout=@var{seconds}
5256 Likewise, when the build or substitution process lasts for more than
5257 @var{seconds}, terminate it and report a build failure.
5259 By default, the daemon's setting is honored (@pxref{Invoking
5260 guix-daemon, @code{--timeout}}).
5262 @item --verbosity=@var{level}
5263 Use the given verbosity level. @var{level} must be an integer between 0
5264 and 5; higher means more verbose output. Setting a level of 4 or more
5265 may be helpful when debugging setup issues with the build daemon.
5267 @item --cores=@var{n}
5269 Allow the use of up to @var{n} CPU cores for the build. The special
5270 value @code{0} means to use as many CPU cores as available.
5272 @item --max-jobs=@var{n}
5274 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5275 guix-daemon, @code{--max-jobs}}, for details about this option and the
5276 equivalent @command{guix-daemon} option.
5280 Behind the scenes, @command{guix build} is essentially an interface to
5281 the @code{package-derivation} procedure of the @code{(guix packages)}
5282 module, and to the @code{build-derivations} procedure of the @code{(guix
5283 derivations)} module.
5285 In addition to options explicitly passed on the command line,
5286 @command{guix build} and other @command{guix} commands that support
5287 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5289 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5290 Users can define this variable to a list of command line options that
5291 will automatically be used by @command{guix build} and other
5292 @command{guix} commands that can perform builds, as in the example
5296 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5299 These options are parsed independently, and the result is appended to
5300 the parsed command-line options.
5304 @node Package Transformation Options
5305 @subsection Package Transformation Options
5307 @cindex package variants
5308 Another set of command-line options supported by @command{guix build}
5309 and also @command{guix package} are @dfn{package transformation
5310 options}. These are options that make it possible to define @dfn{package
5311 variants}---for instance, packages built from different source code.
5312 This is a convenient way to create customized packages on the fly
5313 without having to type in the definitions of package variants
5314 (@pxref{Defining Packages}).
5318 @item --with-source=@var{source}
5319 Use @var{source} as the source of the corresponding package.
5320 @var{source} must be a file name or a URL, as for @command{guix
5321 download} (@pxref{Invoking guix download}).
5323 The ``corresponding package'' is taken to be the one specified on the
5324 command line the name of which matches the base of @var{source}---e.g.,
5325 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5326 package is @code{guile}. Likewise, the version string is inferred from
5327 @var{source}; in the previous example, it is @code{2.0.10}.
5329 This option allows users to try out versions of packages other than the
5330 one provided by the distribution. The example below downloads
5331 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5332 the @code{ed} package:
5335 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5338 As a developer, @code{--with-source} makes it easy to test release
5342 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5345 @dots{} or to build from a checkout in a pristine environment:
5348 $ git clone git://git.sv.gnu.org/guix.git
5349 $ guix build guix --with-source=./guix
5352 @item --with-input=@var{package}=@var{replacement}
5353 Replace dependency on @var{package} by a dependency on
5354 @var{replacement}. @var{package} must be a package name, and
5355 @var{replacement} must be a package specification such as @code{guile}
5356 or @code{guile@@1.8}.
5358 For instance, the following command builds Guix, but replaces its
5359 dependency on the current stable version of Guile with a dependency on
5360 the legacy version of Guile, @code{guile@@2.0}:
5363 guix build --with-input=guile=guile@@2.0 guix
5366 This is a recursive, deep replacement. So in this example, both
5367 @code{guix} and its dependency @code{guile-json} (which also depends on
5368 @code{guile}) get rebuilt against @code{guile@@2.0}.
5370 This is implemented using the @code{package-input-rewriting} Scheme
5371 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5373 @item --with-graft=@var{package}=@var{replacement}
5374 This is similar to @code{--with-input} but with an important difference:
5375 instead of rebuilding the whole dependency chain, @var{replacement} is
5376 built and then @dfn{grafted} onto the binaries that were initially
5377 referring to @var{package}. @xref{Security Updates}, for more
5378 information on grafts.
5380 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5381 and all its dependencies, replacing references to the version of GnuTLS
5382 they currently refer to:
5385 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5388 This has the advantage of being much faster than rebuilding everything.
5389 But there is a caveat: it works if and only if @var{package} and
5390 @var{replacement} are strictly compatible---for example, if they provide
5391 a library, the application binary interface (ABI) of those libraries
5392 must be compatible. If @var{replacement} is somehow incompatible with
5393 @var{package}, then the resulting package may be unusable. Use with
5398 @node Additional Build Options
5399 @subsection Additional Build Options
5401 The command-line options presented below are specific to @command{guix
5408 Build quietly, without displaying the build log. Upon completion, the
5409 build log is kept in @file{/var} (or similar) and can always be
5410 retrieved using the @option{--log-file} option.
5412 @item --file=@var{file}
5413 @itemx -f @var{file}
5415 Build the package or derivation that the code within @var{file}
5418 As an example, @var{file} might contain a package definition like this
5419 (@pxref{Defining Packages}):
5422 @verbatiminclude package-hello.scm
5425 @item --expression=@var{expr}
5426 @itemx -e @var{expr}
5427 Build the package or derivation @var{expr} evaluates to.
5429 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5430 guile-1.8)}, which unambiguously designates this specific variant of
5431 version 1.8 of Guile.
5433 Alternatively, @var{expr} may be a G-expression, in which case it is used
5434 as a build program passed to @code{gexp->derivation}
5435 (@pxref{G-Expressions}).
5437 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5438 (@pxref{The Store Monad}). The procedure must return a derivation as a
5439 monadic value, which is then passed through @code{run-with-store}.
5443 Build the source derivations of the packages, rather than the packages
5446 For instance, @code{guix build -S gcc} returns something like
5447 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5450 The returned source tarball is the result of applying any patches and
5451 code snippets specified in the package @code{origin} (@pxref{Defining
5455 Fetch and return the source of @var{package-or-derivation} and all their
5456 dependencies, recursively. This is a handy way to obtain a local copy
5457 of all the source code needed to build @var{packages}, allowing you to
5458 eventually build them even without network access. It is an extension
5459 of the @code{--source} option and can accept one of the following
5460 optional argument values:
5464 This value causes the @code{--sources} option to behave in the same way
5465 as the @code{--source} option.
5468 Build the source derivations of all packages, including any source that
5469 might be listed as @code{inputs}. This is the default value.
5472 $ guix build --sources tzdata
5473 The following derivations will be built:
5474 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5475 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5479 Build the source derivations of all packages, as well of all transitive
5480 inputs to the packages. This can be used e.g. to
5481 prefetch package source for later offline building.
5484 $ guix build --sources=transitive tzdata
5485 The following derivations will be built:
5486 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5487 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5488 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5489 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5490 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5491 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5497 @item --system=@var{system}
5498 @itemx -s @var{system}
5499 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5500 the system type of the build host.
5502 An example use of this is on Linux-based systems, which can emulate
5503 different personalities. For instance, passing
5504 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5505 to build packages in a complete 32-bit environment.
5507 @item --target=@var{triplet}
5508 @cindex cross-compilation
5509 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5510 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5511 configuration triplets,, autoconf, Autoconf}).
5513 @anchor{build-check}
5515 @cindex determinism, checking
5516 @cindex reproducibility, checking
5517 Rebuild @var{package-or-derivation}, which are already available in the
5518 store, and raise an error if the build results are not bit-for-bit
5521 This mechanism allows you to check whether previously installed
5522 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5523 of a package is deterministic. @xref{Invoking guix challenge}, for more
5524 background information and tools.
5526 When used in conjunction with @option{--keep-failed}, the differing
5527 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5528 This makes it easy to look for differences between the two results.
5531 @cindex repairing store items
5532 @cindex corruption, recovering from
5533 Attempt to repair the specified store items, if they are corrupt, by
5534 re-downloading or rebuilding them.
5536 This operation is not atomic and thus restricted to @code{root}.
5540 Return the derivation paths, not the output paths, of the given
5543 @item --root=@var{file}
5544 @itemx -r @var{file}
5545 @cindex GC roots, adding
5546 @cindex garbage collector roots, adding
5547 Make @var{file} a symlink to the result, and register it as a garbage
5550 Consequently, the results of this @command{guix build} invocation are
5551 protected from garbage collection until @var{file} is removed. When
5552 that option is omitted, build results are eligible for garbage
5553 collection as soon as the build completes. @xref{Invoking guix gc}, for
5557 Return the build log file names or URLs for the given
5558 @var{package-or-derivation}, or raise an error if build logs are
5561 This works regardless of how packages or derivations are specified. For
5562 instance, the following invocations are equivalent:
5565 guix build --log-file `guix build -d guile`
5566 guix build --log-file `guix build guile`
5567 guix build --log-file guile
5568 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5571 If a log is unavailable locally, and unless @code{--no-substitutes} is
5572 passed, the command looks for a corresponding log on one of the
5573 substitute servers (as specified with @code{--substitute-urls}.)
5575 So for instance, imagine you want to see the build log of GDB on MIPS,
5576 but you are actually on an @code{x86_64} machine:
5579 $ guix build --log-file gdb -s mips64el-linux
5580 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5583 You can freely access a huge library of build logs!
5586 @node Debugging Build Failures
5587 @subsection Debugging Build Failures
5589 @cindex build failures, debugging
5590 When defining a new package (@pxref{Defining Packages}), you will
5591 probably find yourself spending some time debugging and tweaking the
5592 build until it succeeds. To do that, you need to operate the build
5593 commands yourself in an environment as close as possible to the one the
5596 To that end, the first thing to do is to use the @option{--keep-failed}
5597 or @option{-K} option of @command{guix build}, which will keep the
5598 failed build tree in @file{/tmp} or whatever directory you specified as
5599 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5601 From there on, you can @command{cd} to the failed build tree and source
5602 the @file{environment-variables} file, which contains all the
5603 environment variable definitions that were in place when the build
5604 failed. So let's say you're debugging a build failure in package
5605 @code{foo}; a typical session would look like this:
5609 @dots{} @i{build fails}
5610 $ cd /tmp/guix-build-foo.drv-0
5611 $ source ./environment-variables
5615 Now, you can invoke commands as if you were the daemon (almost) and
5616 troubleshoot your build process.
5618 Sometimes it happens that, for example, a package's tests pass when you
5619 run them manually but they fail when the daemon runs them. This can
5620 happen because the daemon runs builds in containers where, unlike in our
5621 environment above, network access is missing, @file{/bin/sh} does not
5622 exist, etc. (@pxref{Build Environment Setup}).
5624 In such cases, you may need to run inspect the build process from within
5625 a container similar to the one the build daemon creates:
5630 $ cd /tmp/guix-build-foo.drv-0
5631 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5632 [env]# source ./environment-variables
5636 Here, @command{guix environment -C} creates a container and spawns a new
5637 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5638 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5639 the container, which would may find handy while debugging. The
5640 @option{--no-grafts} option makes sure we get the exact same
5641 environment, with ungrafted packages (@pxref{Security Updates}, for more
5644 To get closer to a container like that used by the build daemon, we can
5645 remove @file{/bin/sh}:
5651 (Don't worry, this is harmless: this is all happening in the throw-away
5652 container created by @command{guix environment}.)
5654 The @command{strace} command is probably not in the search path, but we
5658 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5661 In this way, not only you will have reproduced the environment variables
5662 the daemon uses, you will also be running the build process in a container
5663 similar to the one the daemon uses.
5666 @node Invoking guix edit
5667 @section Invoking @command{guix edit}
5669 @cindex @command{guix edit}
5670 @cindex package definition, editing
5671 So many packages, so many source files! The @command{guix edit} command
5672 facilitates the life of users and packagers by pointing their editor at
5673 the source file containing the definition of the specified packages.
5677 guix edit gcc@@4.9 vim
5681 launches the program specified in the @code{VISUAL} or in the
5682 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5685 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5686 have created your own packages on @code{GUIX_PACKAGE_PATH}
5687 (@pxref{Defining Packages}), you will be able to edit the package
5688 recipes. Otherwise, you will be able to examine the read-only recipes
5689 for packages currently in the store.
5692 @node Invoking guix download
5693 @section Invoking @command{guix download}
5695 @cindex @command{guix download}
5696 @cindex downloading package sources
5697 When writing a package definition, developers typically need to download
5698 a source tarball, compute its SHA256 hash, and write that
5699 hash in the package definition (@pxref{Defining Packages}). The
5700 @command{guix download} tool helps with this task: it downloads a file
5701 from the given URI, adds it to the store, and prints both its file name
5702 in the store and its SHA256 hash.
5704 The fact that the downloaded file is added to the store saves bandwidth:
5705 when the developer eventually tries to build the newly defined package
5706 with @command{guix build}, the source tarball will not have to be
5707 downloaded again because it is already in the store. It is also a
5708 convenient way to temporarily stash files, which may be deleted
5709 eventually (@pxref{Invoking guix gc}).
5711 The @command{guix download} command supports the same URIs as used in
5712 package definitions. In particular, it supports @code{mirror://} URIs.
5713 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5714 Guile bindings for GnuTLS are available in the user's environment; when
5715 they are not available, an error is raised. @xref{Guile Preparations,
5716 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5717 GnuTLS-Guile}, for more information.
5719 @command{guix download} verifies HTTPS server certificates by loading
5720 the certificates of X.509 authorities from the directory pointed to by
5721 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5722 Certificates}), unless @option{--no-check-certificate} is used.
5724 The following options are available:
5727 @item --format=@var{fmt}
5729 Write the hash in the format specified by @var{fmt}. For more
5730 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5732 @item --no-check-certificate
5733 Do not validate the X.509 certificates of HTTPS servers.
5735 When using this option, you have @emph{absolutely no guarantee} that you
5736 are communicating with the authentic server responsible for the given
5737 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5739 @item --output=@var{file}
5740 @itemx -o @var{file}
5741 Save the downloaded file to @var{file} instead of adding it to the
5745 @node Invoking guix hash
5746 @section Invoking @command{guix hash}
5748 @cindex @command{guix hash}
5749 The @command{guix hash} command computes the SHA256 hash of a file.
5750 It is primarily a convenience tool for anyone contributing to the
5751 distribution: it computes the cryptographic hash of a file, which can be
5752 used in the definition of a package (@pxref{Defining Packages}).
5754 The general syntax is:
5757 guix hash @var{option} @var{file}
5760 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5761 hash of data read from standard input. @command{guix hash} has the
5766 @item --format=@var{fmt}
5768 Write the hash in the format specified by @var{fmt}.
5770 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5771 (@code{hex} and @code{hexadecimal} can be used as well).
5773 If the @option{--format} option is not specified, @command{guix hash}
5774 will output the hash in @code{nix-base32}. This representation is used
5775 in the definitions of packages.
5779 Compute the hash on @var{file} recursively.
5781 In this case, the hash is computed on an archive containing @var{file},
5782 including its children if it is a directory. Some of the metadata of
5783 @var{file} is part of the archive; for instance, when @var{file} is a
5784 regular file, the hash is different depending on whether @var{file} is
5785 executable or not. Metadata such as time stamps has no impact on the
5786 hash (@pxref{Invoking guix archive}).
5787 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5792 When combined with @option{--recursive}, exclude version control system
5793 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5796 As an example, here is how you would compute the hash of a Git checkout,
5797 which is useful when using the @code{git-fetch} method (@pxref{origin
5801 $ git clone http://example.org/foo.git
5807 @node Invoking guix import
5808 @section Invoking @command{guix import}
5810 @cindex importing packages
5811 @cindex package import
5812 @cindex package conversion
5813 @cindex Invoking @command{guix import}
5814 The @command{guix import} command is useful for people who would like to
5815 add a package to the distribution with as little work as
5816 possible---a legitimate demand. The command knows of a few
5817 repositories from which it can ``import'' package metadata. The result
5818 is a package definition, or a template thereof, in the format we know
5819 (@pxref{Defining Packages}).
5821 The general syntax is:
5824 guix import @var{importer} @var{options}@dots{}
5827 @var{importer} specifies the source from which to import package
5828 metadata, and @var{options} specifies a package identifier and other
5829 options specific to @var{importer}. Currently, the available
5834 Import metadata for the given GNU package. This provides a template
5835 for the latest version of that GNU package, including the hash of its
5836 source tarball, and its canonical synopsis and description.
5838 Additional information such as the package dependencies and its
5839 license needs to be figured out manually.
5841 For example, the following command returns a package definition for
5845 guix import gnu hello
5848 Specific command-line options are:
5851 @item --key-download=@var{policy}
5852 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5853 keys when verifying the package signature. @xref{Invoking guix
5854 refresh, @code{--key-download}}.
5859 Import metadata from the @uref{https://pypi.python.org/, Python Package
5860 Index}@footnote{This functionality requires Guile-JSON to be installed.
5861 @xref{Requirements}.}. Information is taken from the JSON-formatted
5862 description available at @code{pypi.python.org} and usually includes all
5863 the relevant information, including package dependencies. For maximum
5864 efficiency, it is recommended to install the @command{unzip} utility, so
5865 that the importer can unzip Python wheels and gather data from them.
5867 The command below imports metadata for the @code{itsdangerous} Python
5871 guix import pypi itsdangerous
5876 Import metadata from @uref{https://rubygems.org/,
5877 RubyGems}@footnote{This functionality requires Guile-JSON to be
5878 installed. @xref{Requirements}.}. Information is taken from the
5879 JSON-formatted description available at @code{rubygems.org} and includes
5880 most relevant information, including runtime dependencies. There are
5881 some caveats, however. The metadata doesn't distinguish between
5882 synopses and descriptions, so the same string is used for both fields.
5883 Additionally, the details of non-Ruby dependencies required to build
5884 native extensions is unavailable and left as an exercise to the
5887 The command below imports metadata for the @code{rails} Ruby package:
5890 guix import gem rails
5895 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5896 functionality requires Guile-JSON to be installed.
5897 @xref{Requirements}.}.
5898 Information is taken from the JSON-formatted metadata provided through
5899 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5900 relevant information, such as module dependencies. License information
5901 should be checked closely. If Perl is available in the store, then the
5902 @code{corelist} utility will be used to filter core modules out of the
5903 list of dependencies.
5905 The command command below imports metadata for the @code{Acme::Boolean}
5909 guix import cpan Acme::Boolean
5914 @cindex Bioconductor
5915 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5916 central repository for the @uref{http://r-project.org, GNU@tie{}R
5917 statistical and graphical environment}.
5919 Information is extracted from the @code{DESCRIPTION} file of the package.
5921 The command command below imports metadata for the @code{Cairo}
5925 guix import cran Cairo
5928 When @code{--recursive} is added, the importer will traverse the
5929 dependency graph of the given upstream package recursively and generate
5930 package expressions for all those packages that are not yet in Guix.
5932 When @code{--archive=bioconductor} is added, metadata is imported from
5933 @uref{https://www.bioconductor.org/, Bioconductor}, a repository of R
5934 packages for for the analysis and comprehension of high-throughput
5935 genomic data in bioinformatics.
5937 Information is extracted from the @code{DESCRIPTION} file of a package
5938 published on the web interface of the Bioconductor SVN repository.
5940 The command below imports metadata for the @code{GenomicRanges}
5944 guix import cran --archive=bioconductor GenomicRanges
5950 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5951 comprehensive TeX archive network for TeX packages that are part of the
5952 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5954 Information about the package is obtained through the XML API provided
5955 by CTAN, while the source code is downloaded from the SVN repository of
5956 the Tex Live project. This is done because the CTAN does not keep
5959 The command command below imports metadata for the @code{fontspec}
5963 guix import texlive fontspec
5966 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5967 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5968 tree in the TeX Live SVN repository, but from the specified sibling
5969 directory under the same root.
5971 The command below imports metadata for the @code{ifxetex} package from
5972 CTAN while fetching the sources from the directory
5973 @file{texmf/source/generic}:
5976 guix import texlive --archive=generic ifxetex
5980 @cindex JSON, import
5981 Import package metadata from a local JSON file@footnote{This
5982 functionality requires Guile-JSON to be installed.
5983 @xref{Requirements}.}. Consider the following example package
5984 definition in JSON format:
5990 "source": "mirror://gnu/hello/hello-2.10.tar.gz",
5991 "build-system": "gnu",
5992 "home-page": "https://www.gnu.org/software/hello/",
5993 "synopsis": "Hello, GNU world: An example GNU package",
5994 "description": "GNU Hello prints a greeting.",
5995 "license": "GPL-3.0+",
5996 "native-inputs": ["gcc@@6"]
6000 The field names are the same as for the @code{<package>} record
6001 (@xref{Defining Packages}). References to other packages are provided
6002 as JSON lists of quoted package specification strings such as
6003 @code{guile} or @code{guile@@2.0}.
6005 The importer also supports a more explicit source definition using the
6006 common fields for @code{<origin>} records:
6012 "method": "url-fetch",
6013 "uri": "mirror://gnu/hello/hello-2.10.tar.gz",
6015 "base32": "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"
6022 The command below reads metadata from the JSON file @code{hello.json}
6023 and outputs a package expression:
6026 guix import json hello.json
6030 Import metadata from a local copy of the source of the
6031 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
6032 relies on the @command{nix-instantiate} command of
6033 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
6034 typically written in a mixture of Nix-language and Bash code. This
6035 command only imports the high-level package structure that is written in
6036 the Nix language. It normally includes all the basic fields of a
6039 When importing a GNU package, the synopsis and descriptions are replaced
6040 by their canonical upstream variant.
6042 Usually, you will first need to do:
6045 export NIX_REMOTE=daemon
6049 so that @command{nix-instantiate} does not try to open the Nix database.
6051 As an example, the command below imports the package definition of
6052 LibreOffice (more precisely, it imports the definition of the package
6053 bound to the @code{libreoffice} top-level attribute):
6056 guix import nix ~/path/to/nixpkgs libreoffice
6061 Import metadata from the Haskell community's central package archive
6062 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
6063 Cabal files and includes all the relevant information, including package
6066 Specific command-line options are:
6071 Read a Cabal file from standard input.
6072 @item --no-test-dependencies
6074 Do not include dependencies required only by the test suites.
6075 @item --cabal-environment=@var{alist}
6076 @itemx -e @var{alist}
6077 @var{alist} is a Scheme alist defining the environment in which the
6078 Cabal conditionals are evaluated. The accepted keys are: @code{os},
6079 @code{arch}, @code{impl} and a string representing the name of a flag.
6080 The value associated with a flag has to be either the symbol
6081 @code{true} or @code{false}. The value associated with other keys
6082 has to conform to the Cabal file format definition. The default value
6083 associated with the keys @code{os}, @code{arch} and @code{impl} is
6084 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
6087 The command below imports metadata for the latest version of the
6088 @code{HTTP} Haskell package without including test dependencies and
6089 specifying the value of the flag @samp{network-uri} as @code{false}:
6092 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
6095 A specific package version may optionally be specified by following the
6096 package name by an at-sign and a version number as in the following example:
6099 guix import hackage mtl@@2.1.3.1
6104 The @code{stackage} importer is a wrapper around the @code{hackage} one.
6105 It takes a package name, looks up the package version included in a
6106 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
6107 release and uses the @code{hackage} importer to retrieve its metadata.
6108 Note that it is up to you to select an LTS release compatible with the
6109 GHC compiler used by Guix.
6111 Specific command-line options are:
6114 @item --no-test-dependencies
6116 Do not include dependencies required only by the test suites.
6117 @item --lts-version=@var{version}
6118 @itemx -r @var{version}
6119 @var{version} is the desired LTS release version. If omitted the latest
6123 The command below imports metadata for the @code{HTTP} Haskell package
6124 included in the LTS Stackage release version 7.18:
6127 guix import stackage --lts-version=7.18 HTTP
6132 Import metadata from an Emacs Lisp Package Archive (ELPA) package
6133 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
6135 Specific command-line options are:
6138 @item --archive=@var{repo}
6139 @itemx -a @var{repo}
6140 @var{repo} identifies the archive repository from which to retrieve the
6141 information. Currently the supported repositories and their identifiers
6145 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
6146 identifier. This is the default.
6148 Packages from @code{elpa.gnu.org} are signed with one of the keys
6149 contained in the GnuPG keyring at
6150 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
6151 @code{emacs} package (@pxref{Package Installation, ELPA package
6152 signatures,, emacs, The GNU Emacs Manual}).
6155 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
6156 @code{melpa-stable} identifier.
6159 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
6166 Import metadata from the crates.io Rust package repository
6167 @uref{https://crates.io, crates.io}.
6170 The structure of the @command{guix import} code is modular. It would be
6171 useful to have more importers for other package formats, and your help
6172 is welcome here (@pxref{Contributing}).
6174 @node Invoking guix refresh
6175 @section Invoking @command{guix refresh}
6177 @cindex @command {guix refresh}
6178 The primary audience of the @command{guix refresh} command is developers
6179 of the GNU software distribution. By default, it reports any packages
6180 provided by the distribution that are outdated compared to the latest
6181 upstream version, like this:
6185 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
6186 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
6189 Alternately, one can specify packages to consider, in which case a
6190 warning is emitted for packages that lack an updater:
6193 $ guix refresh coreutils guile guile-ssh
6194 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
6195 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
6198 @command{guix refresh} browses the upstream repository of each package and determines
6199 the highest version number of the releases therein. The command
6200 knows how to update specific types of packages: GNU packages, ELPA
6201 packages, etc.---see the documentation for @option{--type} below. There
6202 are many packages, though, for which it lacks a method to determine
6203 whether a new upstream release is available. However, the mechanism is
6204 extensible, so feel free to get in touch with us to add a new method!
6206 When passed @code{--update}, it modifies distribution source files to
6207 update the version numbers and source tarball hashes of those package
6208 recipes (@pxref{Defining Packages}). This is achieved by downloading
6209 each package's latest source tarball and its associated OpenPGP
6210 signature, authenticating the downloaded tarball against its signature
6211 using @command{gpg}, and finally computing its hash. When the public
6212 key used to sign the tarball is missing from the user's keyring, an
6213 attempt is made to automatically retrieve it from a public key server;
6214 when this is successful, the key is added to the user's keyring; otherwise,
6215 @command{guix refresh} reports an error.
6217 The following options are supported:
6221 @item --expression=@var{expr}
6222 @itemx -e @var{expr}
6223 Consider the package @var{expr} evaluates to.
6225 This is useful to precisely refer to a package, as in this example:
6228 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
6231 This command lists the dependents of the ``final'' libc (essentially all
6236 Update distribution source files (package recipes) in place. This is
6237 usually run from a checkout of the Guix source tree (@pxref{Running
6238 Guix Before It Is Installed}):
6241 $ ./pre-inst-env guix refresh -s non-core -u
6244 @xref{Defining Packages}, for more information on package definitions.
6246 @item --select=[@var{subset}]
6247 @itemx -s @var{subset}
6248 Select all the packages in @var{subset}, one of @code{core} or
6251 The @code{core} subset refers to all the packages at the core of the
6252 distribution---i.e., packages that are used to build ``everything
6253 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
6254 changing one of these packages in the distribution entails a rebuild of
6255 all the others. Thus, such updates are an inconvenience to users in
6256 terms of build time or bandwidth used to achieve the upgrade.
6258 The @code{non-core} subset refers to the remaining packages. It is
6259 typically useful in cases where an update of the core packages would be
6262 @item --manifest=@var{file}
6263 @itemx -m @var{file}
6264 Select all the packages from the manifest in @var{file}. This is useful to
6265 check if any packages of the user manifest can be updated.
6267 @item --type=@var{updater}
6268 @itemx -t @var{updater}
6269 Select only packages handled by @var{updater} (may be a comma-separated
6270 list of updaters). Currently, @var{updater} may be one of:
6274 the updater for GNU packages;
6276 the updater for GNOME packages;
6278 the updater for KDE packages;
6280 the updater for X.org packages;
6282 the updater for packages hosted on kernel.org;
6284 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
6286 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
6288 the updater for @uref{https://www.bioconductor.org/, Bioconductor} R packages;
6290 the updater for @uref{http://www.cpan.org/, CPAN} packages;
6292 the updater for @uref{https://pypi.python.org, PyPI} packages.
6294 the updater for @uref{https://rubygems.org, RubyGems} packages.
6296 the updater for @uref{https://github.com, GitHub} packages.
6298 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6300 the updater for @uref{https://www.stackage.org, Stackage} packages.
6302 the updater for @uref{https://crates.io, Crates} packages.
6305 For instance, the following command only checks for updates of Emacs
6306 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6309 $ guix refresh --type=elpa,cran
6310 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6311 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6316 In addition, @command{guix refresh} can be passed one or more package
6317 names, as in this example:
6320 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6324 The command above specifically updates the @code{emacs} and
6325 @code{idutils} packages. The @code{--select} option would have no
6326 effect in this case.
6328 When considering whether to upgrade a package, it is sometimes
6329 convenient to know which packages would be affected by the upgrade and
6330 should be checked for compatibility. For this the following option may
6331 be used when passing @command{guix refresh} one or more package names:
6335 @item --list-updaters
6337 List available updaters and exit (see @option{--type} above.)
6339 For each updater, display the fraction of packages it covers; at the
6340 end, display the fraction of packages covered by all these updaters.
6342 @item --list-dependent
6344 List top-level dependent packages that would need to be rebuilt as a
6345 result of upgrading one or more packages.
6347 @xref{Invoking guix graph, the @code{reverse-package} type of
6348 @command{guix graph}}, for information on how to visualize the list of
6349 dependents of a package.
6353 Be aware that the @code{--list-dependent} option only
6354 @emph{approximates} the rebuilds that would be required as a result of
6355 an upgrade. More rebuilds might be required under some circumstances.
6358 $ guix refresh --list-dependent flex
6359 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6360 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6363 The command above lists a set of packages that could be built to check
6364 for compatibility with an upgraded @code{flex} package.
6366 The following options can be used to customize GnuPG operation:
6370 @item --gpg=@var{command}
6371 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6372 for in @code{$PATH}.
6374 @item --key-download=@var{policy}
6375 Handle missing OpenPGP keys according to @var{policy}, which may be one
6380 Always download missing OpenPGP keys from the key server, and add them
6381 to the user's GnuPG keyring.
6384 Never try to download missing OpenPGP keys. Instead just bail out.
6387 When a package signed with an unknown OpenPGP key is encountered, ask
6388 the user whether to download it or not. This is the default behavior.
6391 @item --key-server=@var{host}
6392 Use @var{host} as the OpenPGP key server when importing a public key.
6396 The @code{github} updater uses the
6397 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6398 releases. When used repeatedly e.g. when refreshing all packages,
6399 GitHub will eventually refuse to answer any further API requests. By
6400 default 60 API requests per hour are allowed, and a full refresh on all
6401 GitHub packages in Guix requires more than this. Authentication with
6402 GitHub through the use of an API token alleviates these limits. To use
6403 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6404 token procured from @uref{https://github.com/settings/tokens} or
6408 @node Invoking guix lint
6409 @section Invoking @command{guix lint}
6411 @cindex @command{guix lint}
6412 @cindex package, checking for errors
6413 The @command{guix lint} command is meant to help package developers avoid
6414 common errors and use a consistent style. It runs a number of checks on
6415 a given set of packages in order to find common mistakes in their
6416 definitions. Available @dfn{checkers} include (see
6417 @code{--list-checkers} for a complete list):
6422 Validate certain typographical and stylistic rules about package
6423 descriptions and synopses.
6425 @item inputs-should-be-native
6426 Identify inputs that should most likely be native inputs.
6431 @itemx source-file-name
6432 Probe @code{home-page} and @code{source} URLs and report those that are
6433 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6434 the source file name is meaningful, e.g. is not
6435 just a version number or ``git-checkout'', without a declared
6436 @code{file-name} (@pxref{origin Reference}).
6439 @cindex security vulnerabilities
6440 @cindex CVE, Common Vulnerabilities and Exposures
6441 Report known vulnerabilities found in the Common Vulnerabilities and
6442 Exposures (CVE) databases of the current and past year
6443 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6446 To view information about a particular vulnerability, visit pages such as:
6450 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6452 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6456 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6457 @code{CVE-2015-7554}.
6459 Package developers can specify in package recipes the
6460 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6461 name and version of the package when they differ from the name that Guix
6462 uses, as in this example:
6468 ;; CPE calls this package "grub2".
6469 (properties '((cpe-name . "grub2"))))
6473 Warn about obvious source code formatting issues: trailing white space,
6474 use of tabulations, etc.
6477 The general syntax is:
6480 guix lint @var{options} @var{package}@dots{}
6483 If no package is given on the command line, then all packages are checked.
6484 The @var{options} may be zero or more of the following:
6487 @item --list-checkers
6489 List and describe all the available checkers that will be run on packages
6494 Only enable the checkers specified in a comma-separated list using the
6495 names returned by @code{--list-checkers}.
6499 @node Invoking guix size
6500 @section Invoking @command{guix size}
6503 @cindex package size
6505 @cindex @command{guix size}
6506 The @command{guix size} command helps package developers profile the
6507 disk usage of packages. It is easy to overlook the impact of an
6508 additional dependency added to a package, or the impact of using a
6509 single output for a package that could easily be split (@pxref{Packages
6510 with Multiple Outputs}). Such are the typical issues that
6511 @command{guix size} can highlight.
6513 The command can be passed a package specification such as @code{gcc@@4.8}
6514 or @code{guile:debug}, or a file name in the store. Consider this
6518 $ guix size coreutils
6519 store item total self
6520 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6521 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6522 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6523 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6524 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6525 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6529 The store items listed here constitute the @dfn{transitive closure} of
6530 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6531 would be returned by:
6534 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6537 Here the output shows three columns next to store items. The first column,
6538 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6539 the store item---that is, its own size plus the size of all its
6540 dependencies. The next column, labeled ``self'', shows the size of the
6541 item itself. The last column shows the ratio of the size of the item
6542 itself to the space occupied by all the items listed here.
6544 In this example, we see that the closure of Coreutils weighs in at
6545 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6546 large fraction of the closure is not a problem @i{per se} because it is
6547 always available on the system anyway.)
6549 When the package passed to @command{guix size} is available in the
6550 store, @command{guix size} queries the daemon to determine its
6551 dependencies, and measures its size in the store, similar to @command{du
6552 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6555 When the given package is @emph{not} in the store, @command{guix size}
6556 reports information based on the available substitutes
6557 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6558 store items that are not even on disk, only available remotely.
6560 You can also specify several package names:
6563 $ guix size coreutils grep sed bash
6564 store item total self
6565 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6566 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6567 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6568 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6574 In this example we see that the combination of the four packages takes
6575 102.3@tie{}MiB in total, which is much less than the sum of each closure
6576 since they have a lot of dependencies in common.
6578 The available options are:
6582 @item --substitute-urls=@var{urls}
6583 Use substitute information from @var{urls}.
6584 @xref{client-substitute-urls, the same option for @code{guix build}}.
6586 @item --sort=@var{key}
6587 Sort lines according to @var{key}, one of the following options:
6591 the size of each item (the default);
6593 the total size of the item's closure.
6596 @item --map-file=@var{file}
6597 Write a graphical map of disk usage in PNG format to @var{file}.
6599 For the example above, the map looks like this:
6601 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6602 produced by @command{guix size}}
6604 This option requires that
6605 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6606 installed and visible in Guile's module search path. When that is not
6607 the case, @command{guix size} fails as it tries to load it.
6609 @item --system=@var{system}
6610 @itemx -s @var{system}
6611 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6615 @node Invoking guix graph
6616 @section Invoking @command{guix graph}
6619 @cindex @command{guix graph}
6620 @cindex package dependencies
6621 Packages and their dependencies form a @dfn{graph}, specifically a
6622 directed acyclic graph (DAG). It can quickly become difficult to have a
6623 mental model of the package DAG, so the @command{guix graph} command
6624 provides a visual representation of the DAG. By default,
6625 @command{guix graph} emits a DAG representation in the input format of
6626 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6627 directly to the @command{dot} command of Graphviz. It can also emit an
6628 HTML page with embedded JavaScript code to display a ``chord diagram''
6629 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6630 emit Cypher queries to construct a graph in a graph database supporting
6631 the @uref{http://www.opencypher.org/, openCypher} query language.
6632 The general syntax is:
6635 guix graph @var{options} @var{package}@dots{}
6638 For example, the following command generates a PDF file representing the
6639 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6643 guix graph coreutils | dot -Tpdf > dag.pdf
6646 The output looks like this:
6648 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6650 Nice little graph, no?
6652 But there is more than one graph! The one above is concise: it is the
6653 graph of package objects, omitting implicit inputs such as GCC, libc,
6654 grep, etc. It is often useful to have such a concise graph, but
6655 sometimes one may want to see more details. @command{guix graph} supports
6656 several types of graphs, allowing you to choose the level of detail:
6660 This is the default type used in the example above. It shows the DAG of
6661 package objects, excluding implicit dependencies. It is concise, but
6662 filters out many details.
6664 @item reverse-package
6665 This shows the @emph{reverse} DAG of packages. For example:
6668 guix graph --type=reverse-package ocaml
6671 ... yields the graph of packages that depend on OCaml.
6673 Note that for core packages this can yield huge graphs. If all you want
6674 is to know the number of packages that depend on a given package, use
6675 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6676 @option{--list-dependent}}).
6679 This is the package DAG, @emph{including} implicit inputs.
6681 For instance, the following command:
6684 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6687 ... yields this bigger graph:
6689 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6691 At the bottom of the graph, we see all the implicit inputs of
6692 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6694 Now, note that the dependencies of these implicit inputs---that is, the
6695 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6696 here, for conciseness.
6699 Similar to @code{bag-emerged}, but this time including all the bootstrap
6702 @item bag-with-origins
6703 Similar to @code{bag}, but also showing origins and their dependencies.
6706 This is the most detailed representation: It shows the DAG of
6707 derivations (@pxref{Derivations}) and plain store items. Compared to
6708 the above representation, many additional nodes are visible, including
6709 build scripts, patches, Guile modules, etc.
6711 For this type of graph, it is also possible to pass a @file{.drv} file
6712 name instead of a package name, as in:
6715 guix graph -t derivation `guix system build -d my-config.scm`
6719 All the types above correspond to @emph{build-time dependencies}. The
6720 following graph type represents the @emph{run-time dependencies}:
6724 This is the graph of @dfn{references} of a package output, as returned
6725 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6727 If the given package output is not available in the store, @command{guix
6728 graph} attempts to obtain dependency information from substitutes.
6730 Here you can also pass a store file name instead of a package name. For
6731 example, the command below produces the reference graph of your profile
6732 (which can be big!):
6735 guix graph -t references `readlink -f ~/.guix-profile`
6739 This is the graph of the @dfn{referrers} of a store item, as returned by
6740 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6742 This relies exclusively on local information from your store. For
6743 instance, let us suppose that the current Inkscape is available in 10
6744 profiles on your machine; @command{guix graph -t referrers inkscape}
6745 will show a graph rooted at Inkscape and with those 10 profiles linked
6748 It can help determine what is preventing a store item from being garbage
6753 The available options are the following:
6756 @item --type=@var{type}
6757 @itemx -t @var{type}
6758 Produce a graph output of @var{type}, where @var{type} must be one of
6759 the values listed above.
6762 List the supported graph types.
6764 @item --backend=@var{backend}
6765 @itemx -b @var{backend}
6766 Produce a graph using the selected @var{backend}.
6768 @item --list-backends
6769 List the supported graph backends.
6771 Currently, the available backends are Graphviz and d3.js.
6773 @item --expression=@var{expr}
6774 @itemx -e @var{expr}
6775 Consider the package @var{expr} evaluates to.
6777 This is useful to precisely refer to a package, as in this example:
6780 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6785 @node Invoking guix environment
6786 @section Invoking @command{guix environment}
6788 @cindex reproducible build environments
6789 @cindex development environments
6790 @cindex @command{guix environment}
6791 @cindex environment, package build environment
6792 The purpose of @command{guix environment} is to assist hackers in
6793 creating reproducible development environments without polluting their
6794 package profile. The @command{guix environment} tool takes one or more
6795 packages, builds all of their inputs, and creates a shell
6796 environment to use them.
6798 The general syntax is:
6801 guix environment @var{options} @var{package}@dots{}
6804 The following example spawns a new shell set up for the development of
6808 guix environment guile
6811 If the needed dependencies are not built yet, @command{guix environment}
6812 automatically builds them. The environment of the new shell is an augmented
6813 version of the environment that @command{guix environment} was run in.
6814 It contains the necessary search paths for building the given package
6815 added to the existing environment variables. To create a ``pure''
6816 environment, in which the original environment variables have been unset,
6817 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6818 environment variables such as @code{PATH} in their @file{~/.bashrc}
6819 file. As a consequence, when @code{guix environment} launches it, Bash
6820 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6821 environment variables. It is an error to define such environment
6822 variables in @file{.bashrc}; instead, they should be defined in
6823 @file{.bash_profile}, which is sourced only by log-in shells.
6824 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6825 details on Bash start-up files.}.
6827 @vindex GUIX_ENVIRONMENT
6828 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6829 variable in the shell it spawns; its value is the file name of the
6830 profile of this environment. This allows users to, say, define a
6831 specific prompt for development environments in their @file{.bashrc}
6832 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6835 if [ -n "$GUIX_ENVIRONMENT" ]
6837 export PS1="\u@@\h \w [dev]\$ "
6842 ... or to browse the profile:
6845 $ ls "$GUIX_ENVIRONMENT/bin"
6848 Additionally, more than one package may be specified, in which case the
6849 union of the inputs for the given packages are used. For example, the
6850 command below spawns a shell where all of the dependencies of both Guile
6851 and Emacs are available:
6854 guix environment guile emacs
6857 Sometimes an interactive shell session is not desired. An arbitrary
6858 command may be invoked by placing the @code{--} token to separate the
6859 command from the rest of the arguments:
6862 guix environment guile -- make -j4
6865 In other situations, it is more convenient to specify the list of
6866 packages needed in the environment. For example, the following command
6867 runs @command{python} from an environment containing Python@tie{}2.7 and
6871 guix environment --ad-hoc python2-numpy python-2.7 -- python
6874 Furthermore, one might want the dependencies of a package and also some
6875 additional packages that are not build-time or runtime dependencies, but
6876 are useful when developing nonetheless. Because of this, the
6877 @code{--ad-hoc} flag is positional. Packages appearing before
6878 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6879 added to the environment. Packages appearing after are interpreted as
6880 packages that will be added to the environment directly. For example,
6881 the following command creates a Guix development environment that
6882 additionally includes Git and strace:
6885 guix environment guix --ad-hoc git strace
6888 Sometimes it is desirable to isolate the environment as much as
6889 possible, for maximal purity and reproducibility. In particular, when
6890 using Guix on a host distro that is not GuixSD, it is desirable to
6891 prevent access to @file{/usr/bin} and other system-wide resources from
6892 the development environment. For example, the following command spawns
6893 a Guile REPL in a ``container'' where only the store and the current
6894 working directory are mounted:
6897 guix environment --ad-hoc --container guile -- guile
6901 The @code{--container} option requires Linux-libre 3.19 or newer.
6904 The available options are summarized below.
6907 @item --root=@var{file}
6908 @itemx -r @var{file}
6909 @cindex persistent environment
6910 @cindex garbage collector root, for environments
6911 Make @var{file} a symlink to the profile for this environment, and
6912 register it as a garbage collector root.
6914 This is useful if you want to protect your environment from garbage
6915 collection, to make it ``persistent''.
6917 When this option is omitted, the environment is protected from garbage
6918 collection only for the duration of the @command{guix environment}
6919 session. This means that next time you recreate the same environment,
6920 you could have to rebuild or re-download packages. @xref{Invoking guix
6921 gc}, for more on GC roots.
6923 @item --expression=@var{expr}
6924 @itemx -e @var{expr}
6925 Create an environment for the package or list of packages that
6926 @var{expr} evaluates to.
6928 For example, running:
6931 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6934 starts a shell with the environment for this specific variant of the
6940 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6943 starts a shell with all the GuixSD base packages available.
6945 The above commands only use the default output of the given packages.
6946 To select other outputs, two element tuples can be specified:
6949 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6952 @item --load=@var{file}
6953 @itemx -l @var{file}
6954 Create an environment for the package or list of packages that the code
6955 within @var{file} evaluates to.
6957 As an example, @var{file} might contain a definition like this
6958 (@pxref{Defining Packages}):
6961 @verbatiminclude environment-gdb.scm
6965 Include all specified packages in the resulting environment, as if an
6966 @i{ad hoc} package were defined with them as inputs. This option is
6967 useful for quickly creating an environment without having to write a
6968 package expression to contain the desired inputs.
6970 For instance, the command:
6973 guix environment --ad-hoc guile guile-sdl -- guile
6976 runs @command{guile} in an environment where Guile and Guile-SDL are
6979 Note that this example implicitly asks for the default output of
6980 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6981 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6982 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6984 This option may be composed with the default behavior of @command{guix
6985 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6986 as packages whose dependencies will be added to the environment, the
6987 default behavior. Packages appearing after are interpreted as packages
6988 that will be added to the environment directly.
6991 Unset existing environment variables when building the new environment.
6992 This has the effect of creating an environment in which search paths
6993 only contain package inputs.
6995 @item --search-paths
6996 Display the environment variable definitions that make up the
6999 @item --system=@var{system}
7000 @itemx -s @var{system}
7001 Attempt to build for @var{system}---e.g., @code{i686-linux}.
7006 Run @var{command} within an isolated container. The current working
7007 directory outside the container is mapped inside the container.
7008 Additionally, a dummy home directory is created that matches the current
7009 user's home directory, and @file{/etc/passwd} is configured accordingly.
7010 The spawned process runs as the current user outside the container, but
7011 has root privileges in the context of the container.
7015 For containers, share the network namespace with the host system.
7016 Containers created without this flag only have access to the loopback
7019 @item --expose=@var{source}[=@var{target}]
7020 For containers, expose the file system @var{source} from the host system
7021 as the read-only file system @var{target} within the container. If
7022 @var{target} is not specified, @var{source} is used as the target mount
7023 point in the container.
7025 The example below spawns a Guile REPL in a container in which the user's
7026 home directory is accessible read-only via the @file{/exchange}
7030 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
7033 @item --share=@var{source}[=@var{target}]
7034 For containers, share the file system @var{source} from the host system
7035 as the writable file system @var{target} within the container. If
7036 @var{target} is not specified, @var{source} is used as the target mount
7037 point in the container.
7039 The example below spawns a Guile REPL in a container in which the user's
7040 home directory is accessible for both reading and writing via the
7041 @file{/exchange} directory:
7044 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
7048 @command{guix environment}
7049 also supports all of the common build options that @command{guix
7050 build} supports (@pxref{Common Build Options}).
7053 @node Invoking guix publish
7054 @section Invoking @command{guix publish}
7056 @cindex @command{guix publish}
7057 The purpose of @command{guix publish} is to enable users to easily share
7058 their store with others, who can then use it as a substitute server
7059 (@pxref{Substitutes}).
7061 When @command{guix publish} runs, it spawns an HTTP server which allows
7062 anyone with network access to obtain substitutes from it. This means
7063 that any machine running Guix can also act as if it were a build farm,
7064 since the HTTP interface is compatible with Hydra, the software behind
7065 the @code{hydra.gnu.org} build farm.
7067 For security, each substitute is signed, allowing recipients to check
7068 their authenticity and integrity (@pxref{Substitutes}). Because
7069 @command{guix publish} uses the signing key of the system, which is only
7070 readable by the system administrator, it must be started as root; the
7071 @code{--user} option makes it drop root privileges early on.
7073 The signing key pair must be generated before @command{guix publish} is
7074 launched, using @command{guix archive --generate-key} (@pxref{Invoking
7077 The general syntax is:
7080 guix publish @var{options}@dots{}
7083 Running @command{guix publish} without any additional arguments will
7084 spawn an HTTP server on port 8080:
7090 Once a publishing server has been authorized (@pxref{Invoking guix
7091 archive}), the daemon may download substitutes from it:
7094 guix-daemon --substitute-urls=http://example.org:8080
7097 By default, @command{guix publish} compresses archives on the fly as it
7098 serves them. This ``on-the-fly'' mode is convenient in that it requires
7099 no setup and is immediately available. However, when serving lots of
7100 clients, we recommend using the @option{--cache} option, which enables
7101 caching of the archives before they are sent to clients---see below for
7102 details. The @command{guix weather} command provides a handy way to
7103 check what a server provides (@pxref{Invoking guix weather}).
7105 As a bonus, @command{guix publish} also serves as a content-addressed
7106 mirror for source files referenced in @code{origin} records
7107 (@pxref{origin Reference}). For instance, assuming @command{guix
7108 publish} is running on @code{example.org}, the following URL returns the
7109 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
7110 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
7113 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
7116 Obviously, these URLs only work for files that are in the store; in
7117 other cases, they return 404 (``Not Found'').
7119 The following options are available:
7122 @item --port=@var{port}
7123 @itemx -p @var{port}
7124 Listen for HTTP requests on @var{port}.
7126 @item --listen=@var{host}
7127 Listen on the network interface for @var{host}. The default is to
7128 accept connections from any interface.
7130 @item --user=@var{user}
7131 @itemx -u @var{user}
7132 Change privileges to @var{user} as soon as possible---i.e., once the
7133 server socket is open and the signing key has been read.
7135 @item --compression[=@var{level}]
7136 @itemx -C [@var{level}]
7137 Compress data using the given @var{level}. When @var{level} is zero,
7138 disable compression. The range 1 to 9 corresponds to different gzip
7139 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
7142 Unless @option{--cache} is used, compression occurs on the fly and
7143 the compressed streams are not
7144 cached. Thus, to reduce load on the machine that runs @command{guix
7145 publish}, it may be a good idea to choose a low compression level, to
7146 run @command{guix publish} behind a caching proxy, or to use
7147 @option{--cache}. Using @option{--cache} has the advantage that it
7148 allows @command{guix publish} to add @code{Content-Length} HTTP header
7151 @item --cache=@var{directory}
7152 @itemx -c @var{directory}
7153 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
7154 and only serve archives that are in cache.
7156 When this option is omitted, archives and meta-data are created
7157 on-the-fly. This can reduce the available bandwidth, especially when
7158 compression is enabled, since this may become CPU-bound. Another
7159 drawback of the default mode is that the length of archives is not known
7160 in advance, so @command{guix publish} does not add a
7161 @code{Content-Length} HTTP header to its responses, which in turn
7162 prevents clients from knowing the amount of data being downloaded.
7164 Conversely, when @option{--cache} is used, the first request for a store
7165 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
7166 background process to @dfn{bake} the archive---computing its
7167 @code{.narinfo} and compressing the archive, if needed. Once the
7168 archive is cached in @var{directory}, subsequent requests succeed and
7169 are served directly from the cache, which guarantees that clients get
7170 the best possible bandwidth.
7172 The ``baking'' process is performed by worker threads. By default, one
7173 thread per CPU core is created, but this can be customized. See
7174 @option{--workers} below.
7176 When @option{--ttl} is used, cached entries are automatically deleted
7177 when they have expired.
7179 @item --workers=@var{N}
7180 When @option{--cache} is used, request the allocation of @var{N} worker
7181 threads to ``bake'' archives.
7183 @item --ttl=@var{ttl}
7184 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
7185 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
7186 days, @code{1m} means 1 month, and so on.
7188 This allows the user's Guix to keep substitute information in cache for
7189 @var{ttl}. However, note that @code{guix publish} does not itself
7190 guarantee that the store items it provides will indeed remain available
7191 for as long as @var{ttl}.
7193 Additionally, when @option{--cache} is used, cached entries that have
7194 not been accessed for @var{ttl} and that no longer have a corresponding
7195 item in the store, may be deleted.
7197 @item --nar-path=@var{path}
7198 Use @var{path} as the prefix for the URLs of ``nar'' files
7199 (@pxref{Invoking guix archive, normalized archives}).
7201 By default, nars are served at a URL such as
7202 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
7203 change the @code{/nar} part to @var{path}.
7205 @item --public-key=@var{file}
7206 @itemx --private-key=@var{file}
7207 Use the specific @var{file}s as the public/private key pair used to sign
7208 the store items being published.
7210 The files must correspond to the same key pair (the private key is used
7211 for signing and the public key is merely advertised in the signature
7212 metadata). They must contain keys in the canonical s-expression format
7213 as produced by @command{guix archive --generate-key} (@pxref{Invoking
7214 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
7215 @file{/etc/guix/signing-key.sec} are used.
7217 @item --repl[=@var{port}]
7218 @itemx -r [@var{port}]
7219 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
7220 Reference Manual}) on @var{port} (37146 by default). This is used
7221 primarily for debugging a running @command{guix publish} server.
7224 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
7225 instantiate a @code{guix-publish-service-type} service in the @code{services} field
7226 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
7227 @code{guix-publish-service-type}}).
7229 If you are instead running Guix on a ``foreign distro'', follow these
7234 If your host distro uses the systemd init system:
7237 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
7238 /etc/systemd/system/
7239 # systemctl start guix-publish && systemctl enable guix-publish
7243 If your host distro uses the Upstart init system:
7246 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
7247 # start guix-publish
7251 Otherwise, proceed similarly with your distro's init system.
7254 @node Invoking guix challenge
7255 @section Invoking @command{guix challenge}
7257 @cindex reproducible builds
7258 @cindex verifiable builds
7259 @cindex @command{guix challenge}
7261 Do the binaries provided by this server really correspond to the source
7262 code it claims to build? Is a package build process deterministic?
7263 These are the questions the @command{guix challenge} command attempts to
7266 The former is obviously an important question: Before using a substitute
7267 server (@pxref{Substitutes}), one had better @emph{verify} that it
7268 provides the right binaries, and thus @emph{challenge} it. The latter
7269 is what enables the former: If package builds are deterministic, then
7270 independent builds of the package should yield the exact same result,
7271 bit for bit; if a server provides a binary different from the one
7272 obtained locally, it may be either corrupt or malicious.
7274 We know that the hash that shows up in @file{/gnu/store} file names is
7275 the hash of all the inputs of the process that built the file or
7276 directory---compilers, libraries, build scripts,
7277 etc. (@pxref{Introduction}). Assuming deterministic build processes,
7278 one store file name should map to exactly one build output.
7279 @command{guix challenge} checks whether there is, indeed, a single
7280 mapping by comparing the build outputs of several independent builds of
7281 any given store item.
7283 The command output looks like this:
7286 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
7287 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
7288 updating list of substitutes from 'https://guix.example.org'... 100.0%
7289 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
7290 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7291 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7292 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
7293 /gnu/store/@dots{}-git-2.5.0 contents differ:
7294 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
7295 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
7296 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
7297 /gnu/store/@dots{}-pius-2.1.1 contents differ:
7298 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7299 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7300 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
7304 6,406 store items were analyzed:
7305 - 4,749 (74.1%) were identical
7306 - 525 (8.2%) differed
7307 - 1,132 (17.7%) were inconclusive
7311 In this example, @command{guix challenge} first scans the store to
7312 determine the set of locally-built derivations---as opposed to store
7313 items that were downloaded from a substitute server---and then queries
7314 all the substitute servers. It then reports those store items for which
7315 the servers obtained a result different from the local build.
7317 @cindex non-determinism, in package builds
7318 As an example, @code{guix.example.org} always gets a different answer.
7319 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7320 case of Git. This might indicate that the build process of Git is
7321 non-deterministic, meaning that its output varies as a function of
7322 various things that Guix does not fully control, in spite of building
7323 packages in isolated environments (@pxref{Features}). Most common
7324 sources of non-determinism include the addition of timestamps in build
7325 results, the inclusion of random numbers, and directory listings sorted
7326 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7329 To find out what is wrong with this Git binary, we can do something along
7330 these lines (@pxref{Invoking guix archive}):
7333 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7334 | guix archive -x /tmp/git
7335 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7338 This command shows the difference between the files resulting from the
7339 local build, and the files resulting from the build on
7340 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7341 diffutils, Comparing and Merging Files}). The @command{diff} command
7342 works great for text files. When binary files differ, a better option
7343 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7344 visualize differences for all kinds of files.
7346 Once you have done that work, you can tell whether the differences are due
7347 to a non-deterministic build process or to a malicious server. We try
7348 hard to remove sources of non-determinism in packages to make it easier
7349 to verify substitutes, but of course, this is a process that
7350 involves not just Guix, but a large part of the free software community.
7351 In the meantime, @command{guix challenge} is one tool to help address
7354 If you are writing packages for Guix, you are encouraged to check
7355 whether @code{hydra.gnu.org} and other substitute servers obtain the
7356 same build result as you did with:
7359 $ guix challenge @var{package}
7363 where @var{package} is a package specification such as
7364 @code{guile@@2.0} or @code{glibc:debug}.
7366 The general syntax is:
7369 guix challenge @var{options} [@var{packages}@dots{}]
7372 When a difference is found between the hash of a locally-built item and
7373 that of a server-provided substitute, or among substitutes provided by
7374 different servers, the command displays it as in the example above and
7375 its exit code is 2 (other non-zero exit codes denote other kinds of
7378 The one option that matters is:
7382 @item --substitute-urls=@var{urls}
7383 Consider @var{urls} the whitespace-separated list of substitute source
7388 Show details about matches (identical contents) in addition to
7389 information about mismatches.
7393 @node Invoking guix copy
7394 @section Invoking @command{guix copy}
7396 @cindex copy, of store items, over SSH
7397 @cindex SSH, copy of store items
7398 @cindex sharing store items across machines
7399 @cindex transferring store items across machines
7400 The @command{guix copy} command copies items from the store of one
7401 machine to that of another machine over a secure shell (SSH)
7402 connection@footnote{This command is available only when Guile-SSH was
7403 found. @xref{Requirements}, for details.}. For example, the following
7404 command copies the @code{coreutils} package, the user's profile, and all
7405 their dependencies over to @var{host}, logged in as @var{user}:
7408 guix copy --to=@var{user}@@@var{host} \
7409 coreutils `readlink -f ~/.guix-profile`
7412 If some of the items to be copied are already present on @var{host},
7413 they are not actually sent.
7415 The command below retrieves @code{libreoffice} and @code{gimp} from
7416 @var{host}, assuming they are available there:
7419 guix copy --from=@var{host} libreoffice gimp
7422 The SSH connection is established using the Guile-SSH client, which is
7423 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7424 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7426 The key used to sign items that are sent must be accepted by the remote
7427 machine. Likewise, the key used by the remote machine to sign items you
7428 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7429 own daemon. @xref{Invoking guix archive}, for more information about
7430 store item authentication.
7432 The general syntax is:
7435 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7438 You must always specify one of the following options:
7441 @item --to=@var{spec}
7442 @itemx --from=@var{spec}
7443 Specify the host to send to or receive from. @var{spec} must be an SSH
7444 spec such as @code{example.org}, @code{charlie@@example.org}, or
7445 @code{charlie@@example.org:2222}.
7448 The @var{items} can be either package names, such as @code{gimp}, or
7449 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7451 When specifying the name of a package to send, it is first built if
7452 needed, unless @option{--dry-run} was specified. Common build options
7453 are supported (@pxref{Common Build Options}).
7456 @node Invoking guix container
7457 @section Invoking @command{guix container}
7459 @cindex @command{guix container}
7461 As of version @value{VERSION}, this tool is experimental. The interface
7462 is subject to radical change in the future.
7465 The purpose of @command{guix container} is to manipulate processes
7466 running within an isolated environment, commonly known as a
7467 ``container'', typically created by the @command{guix environment}
7468 (@pxref{Invoking guix environment}) and @command{guix system container}
7469 (@pxref{Invoking guix system}) commands.
7471 The general syntax is:
7474 guix container @var{action} @var{options}@dots{}
7477 @var{action} specifies the operation to perform with a container, and
7478 @var{options} specifies the context-specific arguments for the action.
7480 The following actions are available:
7484 Execute a command within the context of a running container.
7489 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7492 @var{pid} specifies the process ID of the running container.
7493 @var{program} specifies an executable file name within the root file
7494 system of the container. @var{arguments} are the additional options that
7495 will be passed to @var{program}.
7497 The following command launches an interactive login shell inside a
7498 GuixSD container, started by @command{guix system container}, and whose
7502 guix container exec 9001 /run/current-system/profile/bin/bash --login
7505 Note that the @var{pid} cannot be the parent process of a container. It
7506 must be PID 1 of the container or one of its child processes.
7510 @node Invoking guix weather
7511 @section Invoking @command{guix weather}
7513 Occasionally you're grumpy because substitutes are lacking and you end
7514 up building packages by yourself (@pxref{Substitutes}). The
7515 @command{guix weather} command reports on substitute availability on the
7516 specified servers so you can have an idea of whether you'll be grumpy
7517 today. It can sometimes be useful info as a user, but it is primarily
7518 useful to people running @command{guix publish} (@pxref{Invoking guix
7521 @cindex statistics, for substitutes
7522 @cindex availability of substitutes
7523 @cindex substitute availability
7524 @cindex weather, substitute availability
7525 Here's a sample run:
7528 $ guix weather --substitute-urls=https://guix.example.org
7529 computing 5,872 package derivations for x86_64-linux...
7530 looking for 6,128 store items on https://guix.example.org..
7531 updating list of substitutes from 'https://guix.example.org'... 100.0%
7532 https://guix.example.org
7533 43.4% substitutes available (2,658 out of 6,128)
7534 7,032.5 MiB of nars (compressed)
7535 19,824.2 MiB on disk (uncompressed)
7536 0.030 seconds per request (182.9 seconds in total)
7537 33.5 requests per second
7540 As you can see, it reports the fraction of all the packages for which
7541 substitutes are available on the server---regardless of whether
7542 substitutes are enabled, and regardless of whether this server's signing
7543 key is authorized. It also reports the size of the compressed archives
7544 (``nars'') provided by the server, the size the corresponding store
7545 items occupy in the store (assuming deduplication is turned off), and
7546 the server's throughput.
7548 To achieve that, @command{guix weather} queries over HTTP(S) meta-data
7549 (@dfn{narinfos}) for all the relevant store items. Like @command{guix
7550 challenge}, it ignores signatures on those substitutes, which is
7551 innocuous since the command only gathers statistics and cannot install
7554 Among other things, it is possible to query specific system types and
7555 specific package sets. The available options are listed below.
7558 @item --substitute-urls=@var{urls}
7559 @var{urls} is the space-separated list of substitute server URLs to
7560 query. When this option is omitted, the default set of substitute
7563 @item --system=@var{system}
7564 @itemx -s @var{system}
7565 Query substitutes for @var{system}---e.g., @code{aarch64-linux}. This
7566 option can be repeated, in which case @command{guix weather} will query
7567 substitutes for several system types.
7569 @item --manifest=@var{file}
7570 Instead of querying substitutes for all the packages, only ask for those
7571 specified in @var{file}. @var{file} must contain a @dfn{manifest}, as
7572 with the @code{-m} option of @command{guix package} (@pxref{Invoking
7577 @c *********************************************************************
7578 @node GNU Distribution
7579 @chapter GNU Distribution
7581 @cindex Guix System Distribution
7583 Guix comes with a distribution of the GNU system consisting entirely of
7584 free software@footnote{The term ``free'' here refers to the
7585 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7586 users of that software}.}. The
7587 distribution can be installed on its own (@pxref{System Installation}),
7588 but it is also possible to install Guix as a package manager on top of
7589 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7590 between the two, we refer to the standalone distribution as the Guix
7591 System Distribution, or GuixSD.
7593 The distribution provides core GNU packages such as GNU libc, GCC, and
7594 Binutils, as well as many GNU and non-GNU applications. The complete
7595 list of available packages can be browsed
7596 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7597 running @command{guix package} (@pxref{Invoking guix package}):
7600 guix package --list-available
7603 Our goal is to provide a practical 100% free software distribution of
7604 Linux-based and other variants of GNU, with a focus on the promotion and
7605 tight integration of GNU components, and an emphasis on programs and
7606 tools that help users exert that freedom.
7608 Packages are currently available on the following platforms:
7613 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7616 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7619 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7620 using the EABI hard-float application binary interface (ABI),
7621 and Linux-Libre kernel.
7624 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7625 currently in an experimental stage, with limited support.
7626 @xref{Contributing}, for how to help!
7628 @item mips64el-linux
7629 little-endian 64-bit MIPS processors, specifically the Loongson series,
7630 n32 ABI, and Linux-Libre kernel.
7634 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7637 For information on porting to other architectures or kernels,
7641 * System Installation:: Installing the whole operating system.
7642 * System Configuration:: Configuring the operating system.
7643 * Documentation:: Browsing software user manuals.
7644 * Installing Debugging Files:: Feeding the debugger.
7645 * Security Updates:: Deploying security fixes quickly.
7646 * Package Modules:: Packages from the programmer's viewpoint.
7647 * Packaging Guidelines:: Growing the distribution.
7648 * Bootstrapping:: GNU/Linux built from scratch.
7649 * Porting:: Targeting another platform or kernel.
7652 Building this distribution is a cooperative effort, and you are invited
7653 to join! @xref{Contributing}, for information about how you can help.
7655 @node System Installation
7656 @section System Installation
7658 @cindex installing GuixSD
7659 @cindex Guix System Distribution
7660 This section explains how to install the Guix System Distribution (GuixSD)
7661 on a machine. The Guix package manager can
7662 also be installed on top of a running GNU/Linux system,
7663 @pxref{Installation}.
7667 @c This paragraph is for people reading this from tty2 of the
7668 @c installation image.
7669 You are reading this documentation with an Info reader. For details on
7670 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7671 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7672 Info}. Hit @kbd{l} afterwards to come back here.
7674 Alternately, run @command{info info} in another tty to keep the manual
7680 * Limitations:: What you can expect.
7681 * Hardware Considerations:: Supported hardware.
7682 * USB Stick Installation:: Preparing the installation medium.
7683 * DVD Installation:: Preparing the installation medium.
7684 * Preparing for Installation:: Networking, partitioning, etc.
7685 * Proceeding with the Installation:: The real thing.
7686 * Installing GuixSD in a VM:: GuixSD playground.
7687 * Building the Installation Image:: How this comes to be.
7691 @subsection Limitations
7693 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7694 not production-ready. It may contain bugs and lack important
7695 features. Thus, if you are looking for a stable production system that
7696 respects your freedom as a computer user, a good solution at this point
7697 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7698 the more established GNU/Linux distributions}. We hope you can soon switch
7699 to the GuixSD without fear, of course. In the meantime, you can
7700 also keep using your distribution and try out the package manager on top
7701 of it (@pxref{Installation}).
7703 Before you proceed with the installation, be aware of the following
7704 noteworthy limitations applicable to version @value{VERSION}:
7708 The installation process does not include a graphical user interface and
7709 requires familiarity with GNU/Linux (see the following subsections to
7710 get a feel of what that means.)
7713 Support for the Logical Volume Manager (LVM) is missing.
7716 More and more system services are provided (@pxref{Services}), but some
7720 More than 5,300 packages are available, but you may
7721 occasionally find that a useful package is missing.
7724 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7725 as well as a number of X11 window managers. However, some graphical
7726 applications may be missing, as well as KDE.
7729 You have been warned! But more than a disclaimer, this is an invitation
7730 to report issues (and success stories!), and to join us in improving it.
7731 @xref{Contributing}, for more info.
7734 @node Hardware Considerations
7735 @subsection Hardware Considerations
7737 @cindex hardware support on GuixSD
7738 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7739 builds around the kernel Linux-libre, which means that only hardware for
7740 which free software drivers and firmware exist is supported. Nowadays,
7741 a wide range of off-the-shelf hardware is supported on
7742 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7743 Ethernet controllers. Unfortunately, there are still areas where
7744 hardware vendors deny users control over their own computing, and such
7745 hardware is not supported on GuixSD.
7747 @cindex WiFi, hardware support
7748 One of the main areas where free drivers or firmware are lacking is WiFi
7749 devices. WiFi devices known to work include those using Atheros chips
7750 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7751 driver, and those using Broadcom/AirForce chips (BCM43xx with
7752 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7753 Linux-libre driver. Free firmware exists for both and is available
7754 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7755 (@pxref{operating-system Reference, @code{firmware}}).
7757 @cindex RYF, Respects Your Freedom
7758 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7759 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7760 certification program for hardware products that respect your freedom
7761 and your privacy and ensure that you have control over your device. We
7762 encourage you to check the list of RYF-certified devices.
7764 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7765 web site. It contains a catalog of hardware devices with information
7766 about their support in GNU/Linux.
7769 @node USB Stick Installation
7770 @subsection USB Stick Installation
7772 An installation image for USB sticks can be downloaded from
7773 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz},
7774 where @var{system} is one of:
7778 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7781 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7784 @c start duplication of authentication part from ``Binary Installation''
7785 Make sure to download the associated @file{.sig} file and to verify the
7786 authenticity of the image against it, along these lines:
7789 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz.sig
7790 $ gpg --verify guixsd-install-@value{VERSION}.@var{system}.xz.sig
7793 If that command fails because you do not have the required public key,
7794 then run this command to import it:
7797 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7801 and rerun the @code{gpg --verify} command.
7804 This image contains the tools necessary for an installation.
7805 It is meant to be copied @emph{as is} to a large-enough USB stick or DVD.
7807 To copy the image to a USB stick, follow these steps:
7811 Decompress the image using the @command{xz} command:
7814 xz -d guixsd-install-@value{VERSION}.@var{system}.xz
7818 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7819 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7820 copy the image with:
7823 dd if=guixsd-install-@value{VERSION}.x86_64 of=/dev/sdX
7827 Access to @file{/dev/sdX} usually requires root privileges.
7830 Once this is done, you should be able to reboot the system and boot from
7831 the USB stick. The latter usually requires you to get in the BIOS or
7832 UEFI boot menu, where you can choose to boot from the USB stick.
7834 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7835 GuixSD in a virtual machine (VM).
7837 @node DVD Installation
7838 @subsection DVD Installation
7840 An installation image for DVDs can be downloaded from
7841 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz},
7842 where @var{system} is one of:
7846 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7849 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7852 @c start duplication of authentication part from ``Binary Installation''
7853 Make sure to download the associated @file{.sig} file and to verify the
7854 authenticity of the image against it, along these lines:
7857 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-install-@value{VERSION}.@var{system}.xz.sig
7858 $ gpg --verify guixsd-install-@value{VERSION}.@var{system}.xz.sig
7861 If that command fails because you do not have the required public key,
7862 then run this command to import it:
7865 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7869 and rerun the @code{gpg --verify} command.
7872 This image contains the tools necessary for an installation.
7873 It is meant to be copied @emph{as is} to a large-enough USB stick or DVD.
7875 To copy the image to a DVD, follow these steps:
7879 Decompress the image using the @command{xz} command:
7882 xz -d guixsd-install-@value{VERSION}.@var{system}.xz
7886 Insert a blank DVD into your machine, and determine
7887 its device name. Assuming that the DVD drive is known as @file{/dev/srX},
7888 copy the image with:
7891 growisofs -dvd-compat -Z /dev/srX=guixsd-install-@value{VERSION}.x86_64
7894 Access to @file{/dev/srX} usually requires root privileges.
7897 Once this is done, you should be able to reboot the system and boot from
7898 the DVD. The latter usually requires you to get in the BIOS or
7899 UEFI boot menu, where you can choose to boot from the DVD.
7901 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7902 GuixSD in a virtual machine (VM).
7904 @node Preparing for Installation
7905 @subsection Preparing for Installation
7907 Once you have successfully booted your computer using the installation medium,
7908 you should end up with a root prompt. Several console TTYs are configured
7909 and can be used to run commands as root. TTY2 shows this documentation,
7910 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7911 Stand-alone GNU Info}). The installation system runs the GPM mouse
7912 daemon, which allows you to select text with the left mouse button and
7913 to paste it with the middle button.
7916 Installation requires access to the Internet so that any missing
7917 dependencies of your system configuration can be downloaded. See the
7918 ``Networking'' section below.
7921 The installation system includes many common tools needed for this task.
7922 But it is also a full-blown GuixSD system, which means that you can
7923 install additional packages, should you need it, using @command{guix
7924 package} (@pxref{Invoking guix package}).
7926 @subsubsection Keyboard Layout
7928 @cindex keyboard layout
7929 The installation image uses the US qwerty keyboard layout. If you want
7930 to change it, you can use the @command{loadkeys} command. For example,
7931 the following command selects the Dvorak keyboard layout:
7937 See the files under @file{/run/current-system/profile/share/keymaps} for
7938 a list of available keyboard layouts. Run @command{man loadkeys} for
7941 @subsubsection Networking
7943 Run the following command see what your network interfaces are called:
7950 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7956 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7957 Wired interfaces have a name starting with @samp{e}; for example, the
7958 interface corresponding to the first on-board Ethernet controller is
7959 called @samp{eno1}. Wireless interfaces have a name starting with
7960 @samp{w}, like @samp{w1p2s0}.
7963 @item Wired connection
7964 To configure a wired network run the following command, substituting
7965 @var{interface} with the name of the wired interface you want to use.
7968 ifconfig @var{interface} up
7971 @item Wireless connection
7974 To configure wireless networking, you can create a configuration file
7975 for the @command{wpa_supplicant} configuration tool (its location is not
7976 important) using one of the available text editors such as
7980 zile wpa_supplicant.conf
7983 As an example, the following stanza can go to this file and will work
7984 for many wireless networks, provided you give the actual SSID and
7985 passphrase for the network you are connecting to:
7989 ssid="@var{my-ssid}"
7991 psk="the network's secret passphrase"
7995 Start the wireless service and run it in the background with the
7996 following command (substitute @var{interface} with the name of the
7997 network interface you want to use):
8000 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
8003 Run @command{man wpa_supplicant} for more information.
8007 At this point, you need to acquire an IP address. On a network where IP
8008 addresses are automatically assigned @i{via} DHCP, you can run:
8011 dhclient -v @var{interface}
8014 Try to ping a server to see if networking is up and running:
8020 Setting up network access is almost always a requirement because the
8021 image does not contain all the software and tools that may be needed.
8023 @cindex installing over SSH
8024 If you want to, you can continue the installation remotely by starting
8028 herd start ssh-daemon
8031 Make sure to either set a password with @command{passwd}, or configure
8032 OpenSSH public key authentication before logging in.
8034 @subsubsection Disk Partitioning
8036 Unless this has already been done, the next step is to partition, and
8037 then format the target partition(s).
8039 The installation image includes several partitioning tools, including
8040 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
8041 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
8042 the partition layout you want:
8048 If your disk uses the GUID Partition Table (GPT) format and you plan to
8049 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
8050 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
8053 @cindex EFI, installation
8054 @cindex UEFI, installation
8055 @cindex ESP, EFI system partition
8056 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
8057 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
8058 must have the @code{esp} flag set. E.g., for @command{parted}:
8061 parted /dev/sda set 1 esp on
8064 Once you are done partitioning the target hard disk drive, you have to
8065 create a file system on the relevant partition(s)@footnote{Currently
8066 GuixSD only supports ext4 and btrfs file systems. In particular, code
8067 that reads partition UUIDs and labels only works for these file system
8068 types.}. For the ESP, if you have one and assuming it is
8069 @file{/dev/sda2}, run:
8072 mkfs.fat -F32 /dev/sda2
8075 Preferably, assign file systems a label so that you can easily and
8076 reliably refer to them in @code{file-system} declarations (@pxref{File
8077 Systems}). This is typically done using the @code{-L} option of
8078 @command{mkfs.ext4} and related commands. So, assuming the target root
8079 partition lives at @file{/dev/sda1}, a file system with the label
8080 @code{my-root} can be created with:
8083 mkfs.ext4 -L my-root /dev/sda1
8086 @cindex encrypted disk
8087 If you are instead planning to encrypt the root partition, you can use
8088 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
8089 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
8090 @code{man cryptsetup}} for more information.) Assuming you want to
8091 store the root partition on @file{/dev/sda1}, the command sequence would
8092 be along these lines:
8095 cryptsetup luksFormat /dev/sda1
8096 cryptsetup open --type luks /dev/sda1 my-partition
8097 mkfs.ext4 -L my-root /dev/mapper/my-partition
8100 Once that is done, mount the target file system under @file{/mnt}
8101 with a command like (again, assuming @code{my-root} is the label of the
8105 mount LABEL=my-root /mnt
8108 Also mount any other partitions you would like to use on the target
8109 system relative to this path. If you have @file{/boot} on a separate
8110 partition for example, mount it at @file{/mnt/boot} now so it is found
8111 by @code{guix system init} afterwards.
8113 Finally, if you plan to use one or more swap partitions (@pxref{Memory
8114 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
8115 sure to initialize them with @command{mkswap}. Assuming you have one
8116 swap partition on @file{/dev/sda2}, you would run:
8123 Alternatively, you may use a swap file. For example, assuming that in
8124 the new system you want to use the file @file{/swapfile} as a swap file,
8125 you would run@footnote{This example will work for many types of file
8126 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
8127 btrfs), the required steps may be different. For details, see the
8128 manual pages for @command{mkswap} and @command{swapon}.}:
8131 # This is 10 GiB of swap space. Adjust "count" to change the size.
8132 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
8133 # For security, make the file readable and writable only by root.
8134 chmod 600 /mnt/swapfile
8135 mkswap /mnt/swapfile
8136 swapon /mnt/swapfile
8139 Note that if you have encrypted the root partition and created a swap
8140 file in its file system as described above, then the encryption also
8141 protects the swap file, just like any other file in that file system.
8143 @node Proceeding with the Installation
8144 @subsection Proceeding with the Installation
8146 With the target partitions ready and the target root mounted on
8147 @file{/mnt}, we're ready to go. First, run:
8150 herd start cow-store /mnt
8153 This makes @file{/gnu/store} copy-on-write, such that packages added to it
8154 during the installation phase are written to the target disk on @file{/mnt}
8155 rather than kept in memory. This is necessary because the first phase of
8156 the @command{guix system init} command (see below) entails downloads or
8157 builds to @file{/gnu/store} which, initially, is an in-memory file system.
8159 Next, you have to edit a file and
8160 provide the declaration of the operating system to be installed. To
8161 that end, the installation system comes with three text editors: GNU nano
8162 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
8163 nvi (a clone of the original BSD @command{vi} editor).
8164 We strongly recommend storing that file on the target root file system, say,
8165 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
8166 configuration file once you have rebooted into the newly-installed system.
8168 @xref{Using the Configuration System}, for an overview of the
8169 configuration file. The example configurations discussed in that
8170 section are available under @file{/etc/configuration} in the
8171 installation image. Thus, to get started with a system configuration
8172 providing a graphical display server (a ``desktop'' system), you can run
8173 something along these lines:
8177 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
8178 # zile /mnt/etc/config.scm
8181 You should pay attention to what your configuration file contains, and
8186 Make sure the @code{grub-configuration} form refers to the target you
8187 want to install GRUB on. It should mention @code{grub-bootloader} if
8188 you are installing GRUB in the legacy way, or @code{grub-efi-bootloader}
8189 for newer UEFI systems. For legacy systems, the @code{target} field
8190 names a device, like @code{/dev/sda}; for UEFI systems it names a path
8191 to a mounted EFI partition, like @code{/boot/efi}, and do make sure the
8192 path is actually mounted.
8195 Be sure that your partition labels match the value of their respective
8196 @code{device} fields in your @code{file-system} configuration, assuming
8197 your @code{file-system} configuration sets the value of @code{title} to
8201 If there are encrypted or RAID partitions, make sure to add a
8202 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
8205 Once you are done preparing the configuration file, the new system must
8206 be initialized (remember that the target root file system is mounted
8210 guix system init /mnt/etc/config.scm /mnt
8214 This copies all the necessary files and installs GRUB on
8215 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
8216 more information, @pxref{Invoking guix system}. This command may trigger
8217 downloads or builds of missing packages, which can take some time.
8219 Once that command has completed---and hopefully succeeded!---you can run
8220 @command{reboot} and boot into the new system. The @code{root} password
8221 in the new system is initially empty; other users' passwords need to be
8222 initialized by running the @command{passwd} command as @code{root},
8223 unless your configuration specifies otherwise
8224 (@pxref{user-account-password, user account passwords}).
8226 @cindex upgrading GuixSD
8227 From then on, you can update GuixSD whenever you want by running
8228 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
8229 then running @command{guix system reconfigure} to build a new system
8230 generation with the latest packages and services (@pxref{Invoking guix
8231 system}). We recommend doing that regularly so that your system
8232 includes the latest security updates (@pxref{Security Updates}).
8234 Join us on @code{#guix} on the Freenode IRC network or on
8235 @file{guix-devel@@gnu.org} to share your experience---good or not so
8238 @node Installing GuixSD in a VM
8239 @subsection Installing GuixSD in a Virtual Machine
8241 @cindex virtual machine, GuixSD installation
8242 @cindex virtual private server (VPS)
8243 @cindex VPS (virtual private server)
8244 If you'd like to install GuixSD in a virtual machine (VM) or on a
8245 virtual private server (VPS) rather than on your beloved machine, this
8248 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
8249 disk image, follow these steps:
8253 First, retrieve and decompress the GuixSD installation image as
8254 described previously (@pxref{USB Stick Installation}).
8257 Create a disk image that will hold the installed system. To make a
8258 qcow2-formatted disk image, use the @command{qemu-img} command:
8261 qemu-img create -f qcow2 guixsd.img 50G
8264 The resulting file will be much smaller than 50 GB (typically less than
8265 1 MB), but it will grow as the virtualized storage device is filled up.
8268 Boot the USB installation image in an VM:
8271 qemu-system-x86_64 -m 1024 -smp 1 \
8272 -net user -net nic,model=virtio -boot menu=on \
8273 -drive file=guixsd-install-@value{VERSION}.@var{system} \
8274 -drive file=guixsd.img
8277 The ordering of the drives matters.
8279 In the VM console, quickly press the @kbd{F12} key to enter the boot
8280 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
8284 You're now root in the VM, proceed with the installation process.
8285 @xref{Preparing for Installation}, and follow the instructions.
8288 Once installation is complete, you can boot the system that's on your
8289 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
8292 @node Building the Installation Image
8293 @subsection Building the Installation Image
8295 @cindex installation image
8296 The installation image described above was built using the @command{guix
8297 system} command, specifically:
8300 guix system disk-image gnu/system/install.scm
8303 Have a look at @file{gnu/system/install.scm} in the source tree,
8304 and see also @ref{Invoking guix system} for more information
8305 about the installation image.
8307 @node System Configuration
8308 @section System Configuration
8310 @cindex system configuration
8311 The Guix System Distribution supports a consistent whole-system configuration
8312 mechanism. By that we mean that all aspects of the global system
8313 configuration---such as the available system services, timezone and
8314 locale settings, user accounts---are declared in a single place. Such
8315 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
8317 One of the advantages of putting all the system configuration under the
8318 control of Guix is that it supports transactional system upgrades, and
8319 makes it possible to roll back to a previous system instantiation,
8320 should something go wrong with the new one (@pxref{Features}). Another
8321 advantage is that it makes it easy to replicate the exact same configuration
8322 across different machines, or at different points in time, without
8323 having to resort to additional administration tools layered on top of
8324 the own tools of the system.
8325 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
8327 This section describes this mechanism. First we focus on the system
8328 administrator's viewpoint---explaining how the system is configured and
8329 instantiated. Then we show how this mechanism can be extended, for
8330 instance to support new system services.
8333 * Using the Configuration System:: Customizing your GNU system.
8334 * operating-system Reference:: Detail of operating-system declarations.
8335 * File Systems:: Configuring file system mounts.
8336 * Mapped Devices:: Block device extra processing.
8337 * User Accounts:: Specifying user accounts.
8338 * Locales:: Language and cultural convention settings.
8339 * Services:: Specifying system services.
8340 * Setuid Programs:: Programs running with root privileges.
8341 * X.509 Certificates:: Authenticating HTTPS servers.
8342 * Name Service Switch:: Configuring libc's name service switch.
8343 * Initial RAM Disk:: Linux-Libre bootstrapping.
8344 * Bootloader Configuration:: Configuring the boot loader.
8345 * Invoking guix system:: Instantiating a system configuration.
8346 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
8347 * Defining Services:: Adding new service definitions.
8350 @node Using the Configuration System
8351 @subsection Using the Configuration System
8353 The operating system is configured by providing an
8354 @code{operating-system} declaration in a file that can then be passed to
8355 the @command{guix system} command (@pxref{Invoking guix system}). A
8356 simple setup, with the default system services, the default Linux-Libre
8357 kernel, initial RAM disk, and boot loader looks like this:
8359 @findex operating-system
8361 @include os-config-bare-bones.texi
8364 This example should be self-describing. Some of the fields defined
8365 above, such as @code{host-name} and @code{bootloader}, are mandatory.
8366 Others, such as @code{packages} and @code{services}, can be omitted, in
8367 which case they get a default value.
8369 Below we discuss the effect of some of the most important fields
8370 (@pxref{operating-system Reference}, for details about all the available
8371 fields), and how to @dfn{instantiate} the operating system using
8372 @command{guix system}.
8374 @unnumberedsubsubsec Globally-Visible Packages
8376 @vindex %base-packages
8377 The @code{packages} field lists packages that will be globally visible
8378 on the system, for all user accounts---i.e., in every user's @code{PATH}
8379 environment variable---in addition to the per-user profiles
8380 (@pxref{Invoking guix package}). The @var{%base-packages} variable
8381 provides all the tools one would expect for basic user and administrator
8382 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
8383 the GNU Zile lightweight text editor, @command{find}, @command{grep},
8384 etc. The example above adds GNU@tie{}Screen and OpenSSH to those,
8385 taken from the @code{(gnu packages screen)} and @code{(gnu packages ssh)}
8386 modules (@pxref{Package Modules}). The
8387 @code{(list package output)} syntax can be used to add a specific output
8391 (use-modules (gnu packages))
8392 (use-modules (gnu packages dns))
8396 (packages (cons (list bind "utils")
8400 @findex specification->package
8401 Referring to packages by variable name, like @var{tcpdump} above, has
8402 the advantage of being unambiguous; it also allows typos and such to be
8403 diagnosed right away as ``unbound variables''. The downside is that one
8404 needs to know which module defines which package, and to augment the
8405 @code{use-package-modules} line accordingly. To avoid that, one can use
8406 the @code{specification->package} procedure of the @code{(gnu packages)}
8407 module, which returns the best package for a given name or name and
8411 (use-modules (gnu packages))
8415 (packages (append (map specification->package
8416 '("tcpdump" "htop" "gnupg@@2.0"))
8420 @unnumberedsubsubsec System Services
8423 @vindex %base-services
8424 The @code{services} field lists @dfn{system services} to be made
8425 available when the system starts (@pxref{Services}).
8426 The @code{operating-system} declaration above specifies that, in
8427 addition to the basic services, we want the @command{lshd} secure shell
8428 daemon listening on port 2222 (@pxref{Networking Services,
8429 @code{lsh-service}}). Under the hood,
8430 @code{lsh-service} arranges so that @code{lshd} is started with the
8431 right command-line options, possibly with supporting configuration files
8432 generated as needed (@pxref{Defining Services}).
8434 @cindex customization, of services
8435 @findex modify-services
8436 Occasionally, instead of using the base services as is, you will want to
8437 customize them. To do this, use @code{modify-services} (@pxref{Service
8438 Reference, @code{modify-services}}) to modify the list.
8440 For example, suppose you want to modify @code{guix-daemon} and Mingetty
8441 (the console log-in) in the @var{%base-services} list (@pxref{Base
8442 Services, @code{%base-services}}). To do that, you can write the
8443 following in your operating system declaration:
8446 (define %my-services
8447 ;; My very own list of services.
8448 (modify-services %base-services
8449 (guix-service-type config =>
8452 (use-substitutes? #f)
8453 (extra-options '("--gc-keep-derivations"))))
8454 (mingetty-service-type config =>
8455 (mingetty-configuration
8456 (inherit config)))))
8460 (services %my-services))
8463 This changes the configuration---i.e., the service parameters---of the
8464 @code{guix-service-type} instance, and that of all the
8465 @code{mingetty-service-type} instances in the @var{%base-services} list.
8466 Observe how this is accomplished: first, we arrange for the original
8467 configuration to be bound to the identifier @code{config} in the
8468 @var{body}, and then we write the @var{body} so that it evaluates to the
8469 desired configuration. In particular, notice how we use @code{inherit}
8470 to create a new configuration which has the same values as the old
8471 configuration, but with a few modifications.
8473 @cindex encrypted disk
8474 The configuration for a typical ``desktop'' usage, with an encrypted
8475 root partition, the X11 display
8476 server, GNOME and Xfce (users can choose which of these desktop
8477 environments to use at the log-in screen by pressing @kbd{F1}), network
8478 management, power management, and more, would look like this:
8481 @include os-config-desktop.texi
8485 A graphical UEFI system with a choice of lightweight window managers
8486 instead of full-blown desktop environments would look like this:
8489 @include os-config-lightweight-desktop.texi
8492 This example refers to the @file{/boot/efi} partition by its UUID,
8493 @code{1234-ABCD}. Replace this UUID with the right UUID on your system,
8494 as returned by the @command{blkid} command.
8496 @xref{Desktop Services}, for the exact list of services provided by
8497 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8498 information about the @code{nss-certs} package that is used here.
8500 Again, @var{%desktop-services} is just a list of service objects. If
8501 you want to remove services from there, you can do so using the
8502 procedures for list filtering (@pxref{SRFI-1 Filtering and
8503 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8504 following expression returns a list that contains all the services in
8505 @var{%desktop-services} minus the Avahi service:
8508 (remove (lambda (service)
8509 (eq? (service-kind service) avahi-service-type))
8513 @unnumberedsubsubsec Instantiating the System
8515 Assuming the @code{operating-system} declaration
8516 is stored in the @file{my-system-config.scm}
8517 file, the @command{guix system reconfigure my-system-config.scm} command
8518 instantiates that configuration, and makes it the default GRUB boot
8519 entry (@pxref{Invoking guix system}).
8521 The normal way to change the system configuration is by updating this
8522 file and re-running @command{guix system reconfigure}. One should never
8523 have to touch files in @file{/etc} or to run commands that modify the
8524 system state such as @command{useradd} or @command{grub-install}. In
8525 fact, you must avoid that since that would not only void your warranty
8526 but also prevent you from rolling back to previous versions of your
8527 system, should you ever need to.
8529 @cindex roll-back, of the operating system
8530 Speaking of roll-back, each time you run @command{guix system
8531 reconfigure}, a new @dfn{generation} of the system is created---without
8532 modifying or deleting previous generations. Old system generations get
8533 an entry in the bootloader boot menu, allowing you to boot them in case
8534 something went wrong with the latest generation. Reassuring, no? The
8535 @command{guix system list-generations} command lists the system
8536 generations available on disk. It is also possible to roll back the
8537 system via the commands @command{guix system roll-back} and
8538 @command{guix system switch-generation}.
8540 Although the command @command{guix system reconfigure} will not modify
8541 previous generations, must take care when the current generation is not
8542 the latest (e.g., after invoking @command{guix system roll-back}), since
8543 the operation might overwrite a later generation (@pxref{Invoking guix
8546 @unnumberedsubsubsec The Programming Interface
8548 At the Scheme level, the bulk of an @code{operating-system} declaration
8549 is instantiated with the following monadic procedure (@pxref{The Store
8552 @deffn {Monadic Procedure} operating-system-derivation os
8553 Return a derivation that builds @var{os}, an @code{operating-system}
8554 object (@pxref{Derivations}).
8556 The output of the derivation is a single directory that refers to all
8557 the packages, configuration files, and other supporting files needed to
8558 instantiate @var{os}.
8561 This procedure is provided by the @code{(gnu system)} module. Along
8562 with @code{(gnu services)} (@pxref{Services}), this module contains the
8563 guts of GuixSD. Make sure to visit it!
8566 @node operating-system Reference
8567 @subsection @code{operating-system} Reference
8569 This section summarizes all the options available in
8570 @code{operating-system} declarations (@pxref{Using the Configuration
8573 @deftp {Data Type} operating-system
8574 This is the data type representing an operating system configuration.
8575 By that, we mean all the global system configuration, not per-user
8576 configuration (@pxref{Using the Configuration System}).
8579 @item @code{kernel} (default: @var{linux-libre})
8580 The package object of the operating system kernel to use@footnote{Currently
8581 only the Linux-libre kernel is supported. In the future, it will be
8582 possible to use the GNU@tie{}Hurd.}.
8584 @item @code{kernel-arguments} (default: @code{'()})
8585 List of strings or gexps representing additional arguments to pass on
8586 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8588 @item @code{bootloader}
8589 The system bootloader configuration object. @xref{Bootloader Configuration}.
8591 @item @code{initrd} (default: @code{base-initrd})
8593 @cindex initial RAM disk
8594 A two-argument monadic procedure that returns an initial RAM disk for
8595 the Linux kernel. @xref{Initial RAM Disk}.
8597 @item @code{firmware} (default: @var{%base-firmware})
8599 List of firmware packages loadable by the operating system kernel.
8601 The default includes firmware needed for Atheros- and Broadcom-based
8602 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8603 respectively). @xref{Hardware Considerations}, for more info on
8606 @item @code{host-name}
8609 @item @code{hosts-file}
8611 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8612 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8613 Reference Manual}). The default is a file with entries for
8614 @code{localhost} and @var{host-name}.
8616 @item @code{mapped-devices} (default: @code{'()})
8617 A list of mapped devices. @xref{Mapped Devices}.
8619 @item @code{file-systems}
8620 A list of file systems. @xref{File Systems}.
8622 @item @code{swap-devices} (default: @code{'()})
8623 @cindex swap devices
8624 A list of strings identifying devices or files to be used for ``swap
8625 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8626 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8627 It is possible to specify a swap file in a file system on a mapped
8628 device, provided that the necessary device mapping and file system are
8629 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8631 @item @code{users} (default: @code{%base-user-accounts})
8632 @itemx @code{groups} (default: @var{%base-groups})
8633 List of user accounts and groups. @xref{User Accounts}.
8635 @item @code{skeletons} (default: @code{(default-skeletons)})
8636 A list target file name/file-like object tuples (@pxref{G-Expressions,
8637 file-like objects}). These are the skeleton files that will be added to
8638 the home directory of newly-created user accounts.
8640 For instance, a valid value may look like this:
8643 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8644 (".guile" ,(plain-file "guile"
8645 "(use-modules (ice-9 readline))
8646 (activate-readline)")))
8649 @item @code{issue} (default: @var{%default-issue})
8650 A string denoting the contents of the @file{/etc/issue} file, which is
8651 displayed when users log in on a text console.
8653 @item @code{packages} (default: @var{%base-packages})
8654 The set of packages installed in the global profile, which is accessible
8655 at @file{/run/current-system/profile}.
8657 The default set includes core utilities and it is good practice to
8658 install non-core utilities in user profiles (@pxref{Invoking guix
8661 @item @code{timezone}
8662 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8664 You can run the @command{tzselect} command to find out which timezone
8665 string corresponds to your region. Choosing an invalid timezone name
8666 causes @command{guix system} to fail.
8668 @item @code{locale} (default: @code{"en_US.utf8"})
8669 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8670 Library Reference Manual}). @xref{Locales}, for more information.
8672 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8673 The list of locale definitions to be compiled and that may be used at
8674 run time. @xref{Locales}.
8676 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8677 The list of GNU@tie{}libc packages whose locale data and tools are used
8678 to build the locale definitions. @xref{Locales}, for compatibility
8679 considerations that justify this option.
8681 @item @code{name-service-switch} (default: @var{%default-nss})
8682 Configuration of the libc name service switch (NSS)---a
8683 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8686 @item @code{services} (default: @var{%base-services})
8687 A list of service objects denoting system services. @xref{Services}.
8689 @item @code{pam-services} (default: @code{(base-pam-services)})
8691 @cindex pluggable authentication modules
8692 Linux @dfn{pluggable authentication module} (PAM) services.
8693 @c FIXME: Add xref to PAM services section.
8695 @item @code{setuid-programs} (default: @var{%setuid-programs})
8696 List of string-valued G-expressions denoting setuid programs.
8697 @xref{Setuid Programs}.
8699 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8700 @cindex sudoers file
8701 The contents of the @file{/etc/sudoers} file as a file-like object
8702 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8704 This file specifies which users can use the @command{sudo} command, what
8705 they are allowed to do, and what privileges they may gain. The default
8706 is that only @code{root} and members of the @code{wheel} group may use
8713 @subsection File Systems
8715 The list of file systems to be mounted is specified in the
8716 @code{file-systems} field of the operating system declaration
8717 (@pxref{Using the Configuration System}). Each file system is declared
8718 using the @code{file-system} form, like this:
8722 (mount-point "/home")
8723 (device "/dev/sda3")
8727 As usual, some of the fields are mandatory---those shown in the example
8728 above---while others can be omitted. These are described below.
8730 @deftp {Data Type} file-system
8731 Objects of this type represent file systems to be mounted. They
8732 contain the following members:
8736 This is a string specifying the type of the file system---e.g.,
8739 @item @code{mount-point}
8740 This designates the place where the file system is to be mounted.
8743 This names the ``source'' of the file system. By default it is the name
8744 of a node under @file{/dev}, but its meaning depends on the @code{title}
8745 field described below.
8747 @item @code{title} (default: @code{'device})
8748 This is a symbol that specifies how the @code{device} field is to be
8751 When it is the symbol @code{device}, then the @code{device} field is
8752 interpreted as a file name; when it is @code{label}, then @code{device}
8753 is interpreted as a partition label name; when it is @code{uuid},
8754 @code{device} is interpreted as a partition unique identifier (UUID).
8756 UUIDs may be converted from their string representation (as shown by the
8757 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8758 @code{uuid} form expects 16-byte UUIDs as defined in
8759 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8760 form of UUID used by the ext2 family of file systems and others, but it
8761 is different from ``UUIDs'' found in FAT file systems, for instance.},
8766 (mount-point "/home")
8769 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8772 The @code{label} and @code{uuid} options offer a way to refer to disk
8773 partitions without having to hard-code their actual device
8774 name@footnote{Note that, while it is tempting to use
8775 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8776 result, this is not recommended: These special device nodes are created
8777 by the udev daemon and may be unavailable at the time the device is
8780 However, when the source of a file system is a mapped device (@pxref{Mapped
8781 Devices}), its @code{device} field @emph{must} refer to the mapped
8782 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8783 @code{title} must be set to @code{'device}. This is required so that
8784 the system knows that mounting the file system depends on having the
8785 corresponding device mapping established.
8787 @item @code{flags} (default: @code{'()})
8788 This is a list of symbols denoting mount flags. Recognized flags
8789 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8790 access to special files), @code{no-suid} (ignore setuid and setgid
8791 bits), and @code{no-exec} (disallow program execution.)
8793 @item @code{options} (default: @code{#f})
8794 This is either @code{#f}, or a string denoting mount options.
8796 @item @code{mount?} (default: @code{#t})
8797 This value indicates whether to automatically mount the file system when
8798 the system is brought up. When set to @code{#f}, the file system gets
8799 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8800 is not automatically mounted.
8802 @item @code{needed-for-boot?} (default: @code{#f})
8803 This Boolean value indicates whether the file system is needed when
8804 booting. If that is true, then the file system is mounted when the
8805 initial RAM disk (initrd) is loaded. This is always the case, for
8806 instance, for the root file system.
8808 @item @code{check?} (default: @code{#t})
8809 This Boolean indicates whether the file system needs to be checked for
8810 errors before being mounted.
8812 @item @code{create-mount-point?} (default: @code{#f})
8813 When true, the mount point is created if it does not exist yet.
8815 @item @code{dependencies} (default: @code{'()})
8816 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8817 representing file systems that must be mounted or mapped devices that
8818 must be opened before (and unmounted or closed after) this one.
8820 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8821 a dependency of @file{/sys/fs/cgroup/cpu} and
8822 @file{/sys/fs/cgroup/memory}.
8824 Another example is a file system that depends on a mapped device, for
8825 example for an encrypted partition (@pxref{Mapped Devices}).
8829 The @code{(gnu system file-systems)} exports the following useful
8832 @defvr {Scheme Variable} %base-file-systems
8833 These are essential file systems that are required on normal systems,
8834 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8835 below.) Operating system declarations should always contain at least
8839 @defvr {Scheme Variable} %pseudo-terminal-file-system
8840 This is the file system to be mounted as @file{/dev/pts}. It supports
8841 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8842 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8843 Manual}). Pseudo-terminals are used by terminal emulators such as
8847 @defvr {Scheme Variable} %shared-memory-file-system
8848 This file system is mounted as @file{/dev/shm} and is used to support
8849 memory sharing across processes (@pxref{Memory-mapped I/O,
8850 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8853 @defvr {Scheme Variable} %immutable-store
8854 This file system performs a read-only ``bind mount'' of
8855 @file{/gnu/store}, making it read-only for all the users including
8856 @code{root}. This prevents against accidental modification by software
8857 running as @code{root} or by system administrators.
8859 The daemon itself is still able to write to the store: it remounts it
8860 read-write in its own ``name space.''
8863 @defvr {Scheme Variable} %binary-format-file-system
8864 The @code{binfmt_misc} file system, which allows handling of arbitrary
8865 executable file types to be delegated to user space. This requires the
8866 @code{binfmt.ko} kernel module to be loaded.
8869 @defvr {Scheme Variable} %fuse-control-file-system
8870 The @code{fusectl} file system, which allows unprivileged users to mount
8871 and unmount user-space FUSE file systems. This requires the
8872 @code{fuse.ko} kernel module to be loaded.
8875 @node Mapped Devices
8876 @subsection Mapped Devices
8878 @cindex device mapping
8879 @cindex mapped devices
8880 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8881 such as a hard disk partition, can be @dfn{mapped} into another device,
8882 usually in @code{/dev/mapper/},
8883 with additional processing over the data that flows through
8884 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8885 concept of a ``mapped device'' and that of a file system: both boil down
8886 to @emph{translating} input/output operations made on a file to
8887 operations on its backing store. Thus, the Hurd implements mapped
8888 devices, like file systems, using the generic @dfn{translator} mechanism
8889 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8890 typical example is encryption device mapping: all writes to the mapped
8891 device are encrypted, and all reads are deciphered, transparently.
8892 Guix extends this notion by considering any device or set of devices that
8893 are @dfn{transformed} in some way to create a new device; for instance,
8894 RAID devices are obtained by @dfn{assembling} several other devices, such
8895 as hard disks or partitions, into a new one that behaves as one partition.
8896 Other examples, not yet implemented, are LVM logical volumes.
8898 Mapped devices are declared using the @code{mapped-device} form,
8899 defined as follows; for examples, see below.
8901 @deftp {Data Type} mapped-device
8902 Objects of this type represent device mappings that will be made when
8903 the system boots up.
8907 This is either a string specifying the name of the block device to be mapped,
8908 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8909 need to be assembled for creating a new one.
8912 This string specifies the name of the resulting mapped device. For
8913 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8914 specifying @code{"my-partition"} leads to the creation of
8915 the @code{"/dev/mapper/my-partition"} device.
8916 For RAID devices of type @code{raid-device-mapping}, the full device name
8917 such as @code{"/dev/md0"} needs to be given.
8920 This must be a @code{mapped-device-kind} object, which specifies how
8921 @var{source} is mapped to @var{target}.
8925 @defvr {Scheme Variable} luks-device-mapping
8926 This defines LUKS block device encryption using the @command{cryptsetup}
8927 command from the package with the same name. It relies on the
8928 @code{dm-crypt} Linux kernel module.
8931 @defvr {Scheme Variable} raid-device-mapping
8932 This defines a RAID device, which is assembled using the @code{mdadm}
8933 command from the package with the same name. It requires a Linux kernel
8934 module for the appropriate RAID level to be loaded, such as @code{raid456}
8935 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8938 @cindex disk encryption
8940 The following example specifies a mapping from @file{/dev/sda3} to
8941 @file{/dev/mapper/home} using LUKS---the
8942 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8943 standard mechanism for disk encryption.
8944 The @file{/dev/mapper/home}
8945 device can then be used as the @code{device} of a @code{file-system}
8946 declaration (@pxref{File Systems}).
8950 (source "/dev/sda3")
8952 (type luks-device-mapping))
8955 Alternatively, to become independent of device numbering, one may obtain
8956 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8960 cryptsetup luksUUID /dev/sda3
8963 and use it as follows:
8967 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8969 (type luks-device-mapping))
8972 @cindex swap encryption
8973 It is also desirable to encrypt swap space, since swap space may contain
8974 sensitive data. One way to accomplish that is to use a swap file in a
8975 file system on a device mapped via LUKS encryption. In this way, the
8976 swap file is encrypted because the entire device is encrypted.
8977 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8979 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8980 may be declared as follows:
8984 (source (list "/dev/sda1" "/dev/sdb1"))
8986 (type raid-device-mapping))
8989 The @file{/dev/md0} device can then be used as the @code{device} of a
8990 @code{file-system} declaration (@pxref{File Systems}).
8991 Note that the RAID level need not be given; it is chosen during the
8992 initial creation and formatting of the RAID device and is determined
8993 automatically later.
8997 @subsection User Accounts
9001 @cindex user accounts
9002 User accounts and groups are entirely managed through the
9003 @code{operating-system} declaration. They are specified with the
9004 @code{user-account} and @code{user-group} forms:
9010 (supplementary-groups '("wheel" ;allow use of sudo, etc.
9012 "video" ;video devices such as webcams
9013 "cdrom")) ;the good ol' CD-ROM
9014 (comment "Bob's sister")
9015 (home-directory "/home/alice"))
9018 When booting or upon completion of @command{guix system reconfigure},
9019 the system ensures that only the user accounts and groups specified in
9020 the @code{operating-system} declaration exist, and with the specified
9021 properties. Thus, account or group creations or modifications made by
9022 directly invoking commands such as @command{useradd} are lost upon
9023 reconfiguration or reboot. This ensures that the system remains exactly
9026 @deftp {Data Type} user-account
9027 Objects of this type represent user accounts. The following members may
9032 The name of the user account.
9036 This is the name (a string) or identifier (a number) of the user group
9037 this account belongs to.
9039 @item @code{supplementary-groups} (default: @code{'()})
9040 Optionally, this can be defined as a list of group names that this
9043 @item @code{uid} (default: @code{#f})
9044 This is the user ID for this account (a number), or @code{#f}. In the
9045 latter case, a number is automatically chosen by the system when the
9048 @item @code{comment} (default: @code{""})
9049 A comment about the account, such as the account owner's full name.
9051 @item @code{home-directory}
9052 This is the name of the home directory for the account.
9054 @item @code{create-home-directory?} (default: @code{#t})
9055 Indicates whether the home directory of this account should be created
9056 if it does not exist yet.
9058 @item @code{shell} (default: Bash)
9059 This is a G-expression denoting the file name of a program to be used as
9060 the shell (@pxref{G-Expressions}).
9062 @item @code{system?} (default: @code{#f})
9063 This Boolean value indicates whether the account is a ``system''
9064 account. System accounts are sometimes treated specially; for instance,
9065 graphical login managers do not list them.
9067 @anchor{user-account-password}
9068 @item @code{password} (default: @code{#f})
9069 You would normally leave this field to @code{#f}, initialize user
9070 passwords as @code{root} with the @command{passwd} command, and then let
9071 users change it with @command{passwd}. Passwords set with
9072 @command{passwd} are of course preserved across reboot and
9075 If you @emph{do} want to have a preset password for an account, then
9076 this field must contain the encrypted password, as a string.
9077 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
9078 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
9079 Manual}, for information on Guile's @code{crypt} procedure.
9085 User group declarations are even simpler:
9088 (user-group (name "students"))
9091 @deftp {Data Type} user-group
9092 This type is for, well, user groups. There are just a few fields:
9096 The name of the group.
9098 @item @code{id} (default: @code{#f})
9099 The group identifier (a number). If @code{#f}, a new number is
9100 automatically allocated when the group is created.
9102 @item @code{system?} (default: @code{#f})
9103 This Boolean value indicates whether the group is a ``system'' group.
9104 System groups have low numerical IDs.
9106 @item @code{password} (default: @code{#f})
9107 What, user groups can have a password? Well, apparently yes. Unless
9108 @code{#f}, this field specifies the password of the group.
9113 For convenience, a variable lists all the basic user groups one may
9116 @defvr {Scheme Variable} %base-groups
9117 This is the list of basic user groups that users and/or packages expect
9118 to be present on the system. This includes groups such as ``root'',
9119 ``wheel'', and ``users'', as well as groups used to control access to
9120 specific devices such as ``audio'', ``disk'', and ``cdrom''.
9123 @defvr {Scheme Variable} %base-user-accounts
9124 This is the list of basic system accounts that programs may expect to
9125 find on a GNU/Linux system, such as the ``nobody'' account.
9127 Note that the ``root'' account is not included here. It is a
9128 special-case and is automatically added whether or not it is specified.
9135 A @dfn{locale} defines cultural conventions for a particular language
9136 and region of the world (@pxref{Locales,,, libc, The GNU C Library
9137 Reference Manual}). Each locale has a name that typically has the form
9138 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
9139 @code{fr_LU.utf8} designates the locale for the French language, with
9140 cultural conventions from Luxembourg, and using the UTF-8 encoding.
9142 @cindex locale definition
9143 Usually, you will want to specify the default locale for the machine
9144 using the @code{locale} field of the @code{operating-system} declaration
9145 (@pxref{operating-system Reference, @code{locale}}).
9147 The selected locale is automatically added to the @dfn{locale
9148 definitions} known to the system if needed, with its codeset inferred
9149 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
9150 @code{UTF-8} codeset. Additional locale definitions can be specified in
9151 the @code{locale-definitions} slot of @code{operating-system}---this is
9152 useful, for instance, if the codeset could not be inferred from the
9153 locale name. The default set of locale definitions includes some widely
9154 used locales, but not all the available locales, in order to save space.
9156 For instance, to add the North Frisian locale for Germany, the value of
9160 (cons (locale-definition
9161 (name "fy_DE.utf8") (source "fy_DE"))
9162 %default-locale-definitions)
9165 Likewise, to save space, one might want @code{locale-definitions} to
9166 list only the locales that are actually used, as in:
9169 (list (locale-definition
9170 (name "ja_JP.eucjp") (source "ja_JP")
9171 (charset "EUC-JP")))
9175 The compiled locale definitions are available at
9176 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
9177 version, which is the default location where the GNU@tie{}libc provided
9178 by Guix looks for locale data. This can be overridden using the
9179 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
9180 @code{LOCPATH} and locale packages}).
9182 The @code{locale-definition} form is provided by the @code{(gnu system
9183 locale)} module. Details are given below.
9185 @deftp {Data Type} locale-definition
9186 This is the data type of a locale definition.
9191 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
9192 Reference Manual}, for more information on locale names.
9195 The name of the source for that locale. This is typically the
9196 @code{@var{language}_@var{territory}} part of the locale name.
9198 @item @code{charset} (default: @code{"UTF-8"})
9199 The ``character set'' or ``code set'' for that locale,
9200 @uref{http://www.iana.org/assignments/character-sets, as defined by
9206 @defvr {Scheme Variable} %default-locale-definitions
9207 A list of commonly used UTF-8 locales, used as the default
9208 value of the @code{locale-definitions} field of @code{operating-system}
9212 @cindex normalized codeset in locale names
9213 These locale definitions use the @dfn{normalized codeset} for the part
9214 that follows the dot in the name (@pxref{Using gettextized software,
9215 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
9216 instance it has @code{uk_UA.utf8} but @emph{not}, say,
9220 @subsubsection Locale Data Compatibility Considerations
9222 @cindex incompatibility, of locale data
9223 @code{operating-system} declarations provide a @code{locale-libcs} field
9224 to specify the GNU@tie{}libc packages that are used to compile locale
9225 declarations (@pxref{operating-system Reference}). ``Why would I
9226 care?'', you may ask. Well, it turns out that the binary format of
9227 locale data is occasionally incompatible from one libc version to
9230 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
9231 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
9232 For instance, a program linked against libc version 2.21 is unable to
9233 read locale data produced with libc 2.22; worse, that program
9234 @emph{aborts} instead of simply ignoring the incompatible locale
9235 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
9236 the incompatible locale data, which is already an improvement.}.
9237 Similarly, a program linked against libc 2.22 can read most, but not
9238 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
9239 data is incompatible); thus calls to @code{setlocale} may fail, but
9240 programs will not abort.
9242 The ``problem'' in GuixSD is that users have a lot of freedom: They can
9243 choose whether and when to upgrade software in their profiles, and might
9244 be using a libc version different from the one the system administrator
9245 used to build the system-wide locale data.
9247 Fortunately, unprivileged users can also install their own locale data
9248 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
9249 @code{GUIX_LOCPATH} and locale packages}).
9251 Still, it is best if the system-wide locale data at
9252 @file{/run/current-system/locale} is built for all the libc versions
9253 actually in use on the system, so that all the programs can access
9254 it---this is especially crucial on a multi-user system. To do that, the
9255 administrator can specify several libc packages in the
9256 @code{locale-libcs} field of @code{operating-system}:
9259 (use-package-modules base)
9263 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
9266 This example would lead to a system containing locale definitions for
9267 both libc 2.21 and the current version of libc in
9268 @file{/run/current-system/locale}.
9272 @subsection Services
9274 @cindex system services
9275 An important part of preparing an @code{operating-system} declaration is
9276 listing @dfn{system services} and their configuration (@pxref{Using the
9277 Configuration System}). System services are typically daemons launched
9278 when the system boots, or other actions needed at that time---e.g.,
9279 configuring network access.
9281 GuixSD has a broad definition of ``service'' (@pxref{Service
9282 Composition}), but many services are managed by the GNU@tie{}Shepherd
9283 (@pxref{Shepherd Services}). On a running system, the @command{herd}
9284 command allows you to list the available services, show their status,
9285 start and stop them, or do other specific operations (@pxref{Jump
9286 Start,,, shepherd, The GNU Shepherd Manual}). For example:
9292 The above command, run as @code{root}, lists the currently defined
9293 services. The @command{herd doc} command shows a synopsis of the given
9298 Run libc's name service cache daemon (nscd).
9301 The @command{start}, @command{stop}, and @command{restart} sub-commands
9302 have the effect you would expect. For instance, the commands below stop
9303 the nscd service and restart the Xorg display server:
9307 Service nscd has been stopped.
9308 # herd restart xorg-server
9309 Service xorg-server has been stopped.
9310 Service xorg-server has been started.
9313 The following sections document the available services, starting with
9314 the core services, that may be used in an @code{operating-system}
9318 * Base Services:: Essential system services.
9319 * Scheduled Job Execution:: The mcron service.
9320 * Log Rotation:: The rottlog service.
9321 * Networking Services:: Network setup, SSH daemon, etc.
9322 * X Window:: Graphical display.
9323 * Printing Services:: Local and remote printer support.
9324 * Desktop Services:: D-Bus and desktop services.
9325 * Database Services:: SQL databases, key-value stores, etc.
9326 * Mail Services:: IMAP, POP3, SMTP, and all that.
9327 * Messaging Services:: Messaging services.
9328 * Telephony Services:: Telephony services.
9329 * Monitoring Services:: Monitoring services.
9330 * Kerberos Services:: Kerberos services.
9331 * Web Services:: Web servers.
9332 * DNS Services:: DNS daemons.
9333 * VPN Services:: VPN daemons.
9334 * Network File System:: NFS related services.
9335 * Continuous Integration:: The Cuirass service.
9336 * Power management Services:: The TLP tool.
9337 * Audio Services:: The MPD.
9338 * Virtualization Services:: Virtualization services.
9339 * Miscellaneous Services:: Other services.
9343 @subsubsection Base Services
9345 The @code{(gnu services base)} module provides definitions for the basic
9346 services that one expects from the system. The services exported by
9347 this module are listed below.
9349 @defvr {Scheme Variable} %base-services
9350 This variable contains a list of basic services (@pxref{Service Types
9351 and Services}, for more information on service objects) one would
9352 expect from the system: a login service (mingetty) on each tty, syslogd,
9353 the libc name service cache daemon (nscd), the udev device manager, and
9356 This is the default value of the @code{services} field of
9357 @code{operating-system} declarations. Usually, when customizing a
9358 system, you will want to append services to @var{%base-services}, like
9362 (cons* (avahi-service) (lsh-service) %base-services)
9366 @defvr {Scheme Variable} special-files-service-type
9367 This is the service that sets up ``special files'' such as
9368 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
9370 The value associated with @code{special-files-service-type} services
9371 must be a list of tuples where the first element is the ``special file''
9372 and the second element is its target. By default it is:
9374 @cindex @file{/bin/sh}
9375 @cindex @file{sh}, in @file{/bin}
9377 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
9380 @cindex @file{/usr/bin/env}
9381 @cindex @file{env}, in @file{/usr/bin}
9382 If you want to add, say, @code{/usr/bin/env} to your system, you can
9386 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
9387 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
9390 Since this is part of @code{%base-services}, you can use
9391 @code{modify-services} to customize the set of special files
9392 (@pxref{Service Reference, @code{modify-services}}). But the simple way
9393 to add a special file is @i{via} the @code{extra-special-file} procedure
9397 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
9398 Use @var{target} as the ``special file'' @var{file}.
9400 For example, adding the following lines to the @code{services} field of
9401 your operating system declaration leads to a @file{/usr/bin/env}
9405 (extra-special-file "/usr/bin/env"
9406 (file-append coreutils "/bin/env"))
9410 @deffn {Scheme Procedure} host-name-service @var{name}
9411 Return a service that sets the host name to @var{name}.
9414 @deffn {Scheme Procedure} login-service @var{config}
9415 Return a service to run login according to @var{config}, a
9416 @code{<login-configuration>} object, which specifies the message of the day,
9420 @deftp {Data Type} login-configuration
9421 This is the data type representing the configuration of login.
9426 @cindex message of the day
9427 A file-like object containing the ``message of the day''.
9429 @item @code{allow-empty-passwords?} (default: @code{#t})
9430 Allow empty passwords by default so that first-time users can log in when
9431 the 'root' account has just been created.
9436 @deffn {Scheme Procedure} mingetty-service @var{config}
9437 Return a service to run mingetty according to @var{config}, a
9438 @code{<mingetty-configuration>} object, which specifies the tty to run, among
9442 @deftp {Data Type} mingetty-configuration
9443 This is the data type representing the configuration of Mingetty, which
9444 provides the default implementation of virtual console log-in.
9449 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
9451 @item @code{auto-login} (default: @code{#f})
9452 When true, this field must be a string denoting the user name under
9453 which the system automatically logs in. When it is @code{#f}, a
9454 user name and password must be entered to log in.
9456 @item @code{login-program} (default: @code{#f})
9457 This must be either @code{#f}, in which case the default log-in program
9458 is used (@command{login} from the Shadow tool suite), or a gexp denoting
9459 the name of the log-in program.
9461 @item @code{login-pause?} (default: @code{#f})
9462 When set to @code{#t} in conjunction with @var{auto-login}, the user
9463 will have to press a key before the log-in shell is launched.
9465 @item @code{mingetty} (default: @var{mingetty})
9466 The Mingetty package to use.
9471 @deffn {Scheme Procedure} agetty-service @var{config}
9472 Return a service to run agetty according to @var{config}, an
9473 @code{<agetty-configuration>} object, which specifies the tty to run,
9477 @deftp {Data Type} agetty-configuration
9478 This is the data type representing the configuration of agetty, which
9479 implements virtual and serial console log-in. See the @code{agetty(8)}
9480 man page for more information.
9485 The name of the console this agetty runs on, as a string---e.g.,
9486 @code{"ttyS0"}. This argument is mandatory.
9488 @item @code{baud-rate} (default: @code{#f})
9489 A string containing a comma-separated list of one or more baud rates, in
9492 @item @code{term} (default: @code{#f})
9493 A string containing the value used for the @code{TERM} environment
9496 @item @code{eight-bits?} (default: @code{#f})
9497 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9500 @item @code{auto-login} (default: @code{#f})
9501 When passed a login name, as a string, the specified user will be logged
9502 in automatically without prompting for their login name or password.
9504 @item @code{no-reset?} (default: @code{#f})
9505 When @code{#t}, don't reset terminal cflags (control modes).
9507 @item @code{host} (default: @code{#f})
9508 This accepts a string containing the "login_host", which will be written
9509 into the @file{/var/run/utmpx} file.
9511 @item @code{remote?} (default: @code{#f})
9512 When set to @code{#t} in conjunction with @var{host}, this will add an
9513 @code{-r} fakehost option to the command line of the login program
9514 specified in @var{login-program}.
9516 @item @code{flow-control?} (default: @code{#f})
9517 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9519 @item @code{no-issue?} (default: @code{#f})
9520 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9521 not be displayed before presenting the login prompt.
9523 @item @code{init-string} (default: @code{#f})
9524 This accepts a string that will be sent to the tty or modem before
9525 sending anything else. It can be used to initialize a modem.
9527 @item @code{no-clear?} (default: @code{#f})
9528 When set to @code{#t}, agetty will not clear the screen before showing
9531 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9532 This must be either a gexp denoting the name of a log-in program, or
9533 unset, in which case the default value is the @command{login} from the
9536 @item @code{local-line} (default: @code{#f})
9537 Control the CLOCAL line flag. This accepts one of three symbols as
9538 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9539 the default value chosen by agetty is @code{'auto}.
9541 @item @code{extract-baud?} (default: @code{#f})
9542 When set to @code{#t}, instruct agetty to try to extract the baud rate
9543 from the status messages produced by certain types of modems.
9545 @item @code{skip-login?} (default: @code{#f})
9546 When set to @code{#t}, do not prompt the user for a login name. This
9547 can be used with @var{login-program} field to use non-standard login
9550 @item @code{no-newline?} (default: @code{#f})
9551 When set to @code{#t}, do not print a newline before printing the
9552 @file{/etc/issue} file.
9554 @c Is this dangerous only when used with login-program, or always?
9555 @item @code{login-options} (default: @code{#f})
9556 This option accepts a string containing options that are passed to the
9557 login program. When used with the @var{login-program}, be aware that a
9558 malicious user could try to enter a login name containing embedded
9559 options that could be parsed by the login program.
9561 @item @code{login-pause} (default: @code{#f})
9562 When set to @code{#t}, wait for any key before showing the login prompt.
9563 This can be used in conjunction with @var{auto-login} to save memory by
9564 lazily spawning shells.
9566 @item @code{chroot} (default: @code{#f})
9567 Change root to the specified directory. This option accepts a directory
9570 @item @code{hangup?} (default: @code{#f})
9571 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9574 @item @code{keep-baud?} (default: @code{#f})
9575 When set to @code{#t}, try to keep the existing baud rate. The baud
9576 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9579 @item @code{timeout} (default: @code{#f})
9580 When set to an integer value, terminate if no user name could be read
9581 within @var{timeout} seconds.
9583 @item @code{detect-case?} (default: @code{#f})
9584 When set to @code{#t}, turn on support for detecting an uppercase-only
9585 terminal. This setting will detect a login name containing only
9586 uppercase letters as indicating an uppercase-only terminal and turn on
9587 some upper-to-lower case conversions. Note that this will not support
9590 @item @code{wait-cr?} (default: @code{#f})
9591 When set to @code{#t}, wait for the user or modem to send a
9592 carriage-return or linefeed character before displaying
9593 @file{/etc/issue} or login prompt. This is typically used with the
9594 @var{init-string} option.
9596 @item @code{no-hints?} (default: @code{#f})
9597 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9600 @item @code{no-hostname?} (default: @code{#f})
9601 By default, the hostname is printed. When this option is set to
9602 @code{#t}, no hostname will be shown at all.
9604 @item @code{long-hostname?} (default: @code{#f})
9605 By default, the hostname is only printed until the first dot. When this
9606 option is set to @code{#t}, the fully qualified hostname by
9607 @code{gethostname} or @code{getaddrinfo} is shown.
9609 @item @code{erase-characters} (default: @code{#f})
9610 This option accepts a string of additional characters that should be
9611 interpreted as backspace when the user types their login name.
9613 @item @code{kill-characters} (default: @code{#f})
9614 This option accepts a string that should be interpreted to mean "ignore
9615 all previous characters" (also called a "kill" character) when the types
9618 @item @code{chdir} (default: @code{#f})
9619 This option accepts, as a string, a directory path that will be changed
9622 @item @code{delay} (default: @code{#f})
9623 This options accepts, as an integer, the number of seconds to sleep
9624 before opening the tty and displaying the login prompt.
9626 @item @code{nice} (default: @code{#f})
9627 This option accepts, as an integer, the nice value with which to run the
9628 @command{login} program.
9630 @item @code{extra-options} (default: @code{'()})
9631 This option provides an "escape hatch" for the user to provide arbitrary
9632 command-line arguments to @command{agetty} as a list of strings.
9637 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9638 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9639 according to @var{config}, a @code{<kmscon-configuration>} object, which
9640 specifies the tty to run, among other things.
9643 @deftp {Data Type} kmscon-configuration
9644 This is the data type representing the configuration of Kmscon, which
9645 implements virtual console log-in.
9649 @item @code{virtual-terminal}
9650 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9652 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9653 A gexp denoting the name of the log-in program. The default log-in program is
9654 @command{login} from the Shadow tool suite.
9656 @item @code{login-arguments} (default: @code{'("-p")})
9657 A list of arguments to pass to @command{login}.
9659 @item @code{hardware-acceleration?} (default: #f)
9660 Whether to use hardware acceleration.
9662 @item @code{kmscon} (default: @var{kmscon})
9663 The Kmscon package to use.
9668 @cindex name service cache daemon
9670 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9671 [#:name-services '()]
9672 Return a service that runs the libc name service cache daemon (nscd) with the
9673 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9674 Service Switch}, for an example.
9677 @defvr {Scheme Variable} %nscd-default-configuration
9678 This is the default @code{<nscd-configuration>} value (see below) used
9679 by @code{nscd-service}. It uses the caches defined by
9680 @var{%nscd-default-caches}; see below.
9683 @deftp {Data Type} nscd-configuration
9684 This is the data type representing the name service cache daemon (nscd)
9689 @item @code{name-services} (default: @code{'()})
9690 List of packages denoting @dfn{name services} that must be visible to
9691 the nscd---e.g., @code{(list @var{nss-mdns})}.
9693 @item @code{glibc} (default: @var{glibc})
9694 Package object denoting the GNU C Library providing the @command{nscd}
9697 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9698 Name of the nscd log file. This is where debugging output goes when
9699 @code{debug-level} is strictly positive.
9701 @item @code{debug-level} (default: @code{0})
9702 Integer denoting the debugging levels. Higher numbers mean that more
9703 debugging output is logged.
9705 @item @code{caches} (default: @var{%nscd-default-caches})
9706 List of @code{<nscd-cache>} objects denoting things to be cached; see
9712 @deftp {Data Type} nscd-cache
9713 Data type representing a cache database of nscd and its parameters.
9717 @item @code{database}
9718 This is a symbol representing the name of the database to be cached.
9719 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9720 @code{services}, which designate the corresponding NSS database
9721 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9723 @item @code{positive-time-to-live}
9724 @itemx @code{negative-time-to-live} (default: @code{20})
9725 A number representing the number of seconds during which a positive or
9726 negative lookup result remains in cache.
9728 @item @code{check-files?} (default: @code{#t})
9729 Whether to check for updates of the files corresponding to
9732 For instance, when @var{database} is @code{hosts}, setting this flag
9733 instructs nscd to check for updates in @file{/etc/hosts} and to take
9736 @item @code{persistent?} (default: @code{#t})
9737 Whether the cache should be stored persistently on disk.
9739 @item @code{shared?} (default: @code{#t})
9740 Whether the cache should be shared among users.
9742 @item @code{max-database-size} (default: 32@tie{}MiB)
9743 Maximum size in bytes of the database cache.
9745 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9746 @c settings, so leave them out.
9751 @defvr {Scheme Variable} %nscd-default-caches
9752 List of @code{<nscd-cache>} objects used by default by
9753 @code{nscd-configuration} (see above).
9755 It enables persistent and aggressive caching of service and host name
9756 lookups. The latter provides better host name lookup performance,
9757 resilience in the face of unreliable name servers, and also better
9758 privacy---often the result of host name lookups is in local cache, so
9759 external name servers do not even need to be queried.
9762 @anchor{syslog-configuration-type}
9765 @deftp {Data Type} syslog-configuration
9766 This data type represents the configuration of the syslog daemon.
9769 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9770 The syslog daemon to use.
9772 @item @code{config-file} (default: @code{%default-syslog.conf})
9773 The syslog configuration file to use.
9778 @anchor{syslog-service}
9780 @deffn {Scheme Procedure} syslog-service @var{config}
9781 Return a service that runs a syslog daemon according to @var{config}.
9783 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9784 information on the configuration file syntax.
9787 @anchor{guix-configuration-type}
9788 @deftp {Data Type} guix-configuration
9789 This data type represents the configuration of the Guix build daemon.
9790 @xref{Invoking guix-daemon}, for more information.
9793 @item @code{guix} (default: @var{guix})
9794 The Guix package to use.
9796 @item @code{build-group} (default: @code{"guixbuild"})
9797 Name of the group for build user accounts.
9799 @item @code{build-accounts} (default: @code{10})
9800 Number of build user accounts to create.
9802 @item @code{authorize-key?} (default: @code{#t})
9803 @cindex substitutes, authorization thereof
9804 Whether to authorize the substitute keys listed in
9805 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9806 (@pxref{Substitutes}).
9808 @vindex %default-authorized-guix-keys
9809 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9810 The list of authorized key files for archive imports, as a list of
9811 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9812 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9814 @item @code{use-substitutes?} (default: @code{#t})
9815 Whether to use substitutes.
9817 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9818 The list of URLs where to look for substitutes by default.
9820 @item @code{max-silent-time} (default: @code{0})
9821 @itemx @code{timeout} (default: @code{0})
9822 The number of seconds of silence and the number of seconds of activity,
9823 respectively, after which a build process times out. A value of zero
9824 disables the timeout.
9826 @item @code{extra-options} (default: @code{'()})
9827 List of extra command-line options for @command{guix-daemon}.
9829 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9830 File where @command{guix-daemon}'s standard output and standard error
9833 @item @code{http-proxy} (default: @code{#f})
9834 The HTTP proxy used for downloading fixed-output derivations and
9837 @item @code{tmpdir} (default: @code{#f})
9838 A directory path where the @command{guix-daemon} will perform builds.
9843 @deffn {Scheme Procedure} guix-service @var{config}
9844 Return a service that runs the Guix build daemon according to
9848 @deffn {Scheme Procedure} udev-service [#:udev @var{eudev} #:rules @code{'()}]
9849 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9850 udev rules can be provided as a list of files through the @var{rules}
9851 variable. The procedures @var{udev-rule} and @var{file->udev-rule} from
9852 @code{(gnu services base)} simplify the creation of such rule files.
9854 @deffn {Scheme Procedure} udev-rule [@var{file-name} @var{contents}]
9855 Return a udev-rule file named @var{file-name} containing the rules
9856 defined by the @var{contents} literal.
9858 In the following example, a rule for a USB device is defined to be
9859 stored in the file @file{90-usb-thing.rules}. The rule runs a script
9860 upon detecting a USB device with a given product identifier.
9863 (define %example-udev-rule
9865 "90-usb-thing.rules"
9866 (string-append "ACTION==\"add\", SUBSYSTEM==\"usb\", "
9867 "ATTR@{product@}==\"Example\", "
9868 "RUN+=\"/path/to/script\"")))
9872 Here we show how the default @var{udev-service} can be extended with it.
9878 (modify-services %desktop-services
9879 (udev-service-type config =>
9880 (udev-configuration (inherit config)
9881 (rules (append (udev-configuration-rules config)
9882 (list %example-udev-rule))))))))
9885 @deffn {Scheme Procedure} file->udev-rule [@var{file-name} @var{file}]
9886 Return a udev file named @var{file-name} containing the rules defined
9887 within @var{file}, a file-like object.
9889 The following example showcases how we can use an existing rule file.
9892 (use-modules (guix download) ;for url-fetch
9893 (guix packages) ;for origin
9896 (define %android-udev-rules
9898 "51-android-udev.rules"
9899 (let ((version "20170910"))
9902 (uri (string-append "https://raw.githubusercontent.com/M0Rf30/"
9903 "android-udev-rules/" version "/51-android.rules"))
9905 (base32 "0lmmagpyb6xsq6zcr2w1cyx9qmjqmajkvrdbhjx32gqf1d9is003"))))))
9909 Additionally, Guix package definitions can be included in @var{rules} in
9910 order to extend the udev rules with the definitions found under their
9911 @file{lib/udev/rules.d} sub-directory. In lieu of the previous
9912 @var{file->udev-rule} example, we could have used the
9913 @var{android-udev-rules} package which exists in Guix in the @code{(gnu
9914 packages android)} module.
9916 The following example shows how to use the @var{android-udev-rules}
9917 package so that the Android tool @command{adb} can detect devices
9918 without root privileges. It also details how to create the
9919 @code{adbusers} group, which is required for the proper functioning of
9920 the rules defined within the @var{android-udev-rules} package. To
9921 create such a group, we must define it both as part of the
9922 @var{supplementary-groups} of our @var{user-account} declaration, as
9923 well as in the @var{groups} field of the @var{operating-system} record.
9926 (use-modules (gnu packages android) ;for android-udev-rules
9927 (gnu system shadow) ;for user-group
9932 (users (cons (user-acount
9934 (supplementary-groups
9935 '("adbusers" ;for adb
9936 "wheel" "netdev" "audio" "video"))
9939 (groups (cons (user-group (system? #t) (name "adbusers"))
9945 (modify-services %desktop-services
9946 (udev-service-type config =>
9947 (udev-configuration (inherit config)
9948 (rules (cons* android-udev-rules
9949 (udev-configuration-rules config))))))))
9953 @deffn {Scheme Procedure} urandom-seed-service
9954 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9958 @defvr {Scheme Variable} %random-seed-file
9959 This is the name of the file where some random bytes are saved by
9960 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9961 It defaults to @file{/var/lib/random-seed}.
9966 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9967 @cindex keyboard layout
9968 Return a service to load console keymaps from @var{files} using
9969 @command{loadkeys} command. Most likely, you want to load some default
9970 keymap, which can be done like this:
9973 (console-keymap-service "dvorak")
9976 Or, for example, for a Swedish keyboard, you may need to combine
9977 the following keymaps:
9979 (console-keymap-service "se-lat6" "se-fi-lat6")
9982 Also you can specify a full file name (or file names) of your keymap(s).
9983 See @code{man loadkeys} for details.
9989 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9991 Run @var{gpm}, the general-purpose mouse daemon, with the given
9992 command-line @var{options}. GPM allows users to use the mouse in the console,
9993 notably to select, copy, and paste text. The default value of @var{options}
9994 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9996 This service is not part of @var{%base-services}.
9999 @anchor{guix-publish-service-type}
10000 @deffn {Scheme Variable} guix-publish-service-type
10001 This is the service type for @command{guix publish} (@pxref{Invoking
10002 guix publish}). Its value must be a @code{guix-configuration}
10003 object, as described below.
10005 This assumes that @file{/etc/guix} already contains a signing key pair as
10006 created by @command{guix archive --generate-key} (@pxref{Invoking guix
10007 archive}). If that is not the case, the service will fail to start.
10010 @deftp {Data Type} guix-publish-configuration
10011 Data type representing the configuration of the @code{guix publish}
10015 @item @code{guix} (default: @code{guix})
10016 The Guix package to use.
10018 @item @code{port} (default: @code{80})
10019 The TCP port to listen for connections.
10021 @item @code{host} (default: @code{"localhost"})
10022 The host (and thus, network interface) to listen to. Use
10023 @code{"0.0.0.0"} to listen on all the network interfaces.
10025 @item @code{compression-level} (default: @code{3})
10026 The gzip compression level at which substitutes are compressed. Use
10027 @code{0} to disable compression altogether, and @code{9} to get the best
10028 compression ratio at the expense of increased CPU usage.
10030 @item @code{nar-path} (default: @code{"nar"})
10031 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
10032 publish, @code{--nar-path}}, for details.
10034 @item @code{cache} (default: @code{#f})
10035 When it is @code{#f}, disable caching and instead generate archives on
10036 demand. Otherwise, this should be the name of a directory---e.g.,
10037 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
10038 archives and meta-data ready to be sent. @xref{Invoking guix publish,
10039 @option{--cache}}, for more information on the tradeoffs involved.
10041 @item @code{workers} (default: @code{#f})
10042 When it is an integer, this is the number of worker threads used for
10043 caching; when @code{#f}, the number of processors is used.
10044 @xref{Invoking guix publish, @option{--workers}}, for more information.
10046 @item @code{ttl} (default: @code{#f})
10047 When it is an integer, this denotes the @dfn{time-to-live} of the
10048 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
10053 @anchor{rngd-service}
10054 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
10055 [#:device "/dev/hwrng"]
10056 Return a service that runs the @command{rngd} program from @var{rng-tools}
10057 to add @var{device} to the kernel's entropy pool. The service will fail if
10058 @var{device} does not exist.
10061 @anchor{pam-limits-service}
10062 @cindex session limits
10065 @deffn {Scheme Procedure} pam-limits-service [#:limits @code{'()}]
10067 Return a service that installs a configuration file for the
10068 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
10069 @code{pam_limits} module}. The procedure optionally takes a list of
10070 @code{pam-limits-entry} values, which can be used to specify
10071 @code{ulimit} limits and nice priority limits to user sessions.
10073 The following limits definition sets two hard and soft limits for all
10074 login sessions of users in the @code{realtime} group:
10077 (pam-limits-service
10079 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
10080 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
10083 The first entry increases the maximum realtime priority for
10084 non-privileged processes; the second entry lifts any restriction of the
10085 maximum address space that can be locked in memory. These settings are
10086 commonly used for real-time audio systems.
10089 @node Scheduled Job Execution
10090 @subsubsection Scheduled Job Execution
10094 @cindex scheduling jobs
10095 The @code{(gnu services mcron)} module provides an interface to
10096 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
10097 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
10098 Unix @command{cron} daemon; the main difference is that it is
10099 implemented in Guile Scheme, which provides a lot of flexibility when
10100 specifying the scheduling of jobs and their actions.
10102 The example below defines an operating system that runs the
10103 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
10104 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
10105 well as the @command{mkid} command on behalf of an unprivileged user
10106 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
10107 gexps to introduce job definitions that are passed to mcron
10108 (@pxref{G-Expressions}).
10111 (use-modules (guix) (gnu) (gnu services mcron))
10112 (use-package-modules base idutils)
10114 (define updatedb-job
10115 ;; Run 'updatedb' at 3AM every day. Here we write the
10116 ;; job's action as a Scheme procedure.
10117 #~(job '(next-hour '(3))
10119 (execl (string-append #$findutils "/bin/updatedb")
10121 "--prunepaths=/tmp /var/tmp /gnu/store"))))
10123 (define garbage-collector-job
10124 ;; Collect garbage 5 minutes after midnight every day.
10125 ;; The job's action is a shell command.
10126 #~(job "5 0 * * *" ;Vixie cron syntax
10129 (define idutils-job
10130 ;; Update the index database as user "charlie" at 12:15PM
10131 ;; and 19:15PM. This runs from the user's home directory.
10132 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
10133 (string-append #$idutils "/bin/mkid src")
10138 (services (cons (mcron-service (list garbage-collector-job
10144 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
10145 for more information on mcron job specifications. Below is the
10146 reference of the mcron service.
10148 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
10149 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
10150 list of gexps denoting mcron job specifications.
10152 This is a shorthand for:
10154 (service mcron-service-type
10155 (mcron-configuration (mcron mcron) (jobs jobs)))
10159 @defvr {Scheme Variable} mcron-service-type
10160 This is the type of the @code{mcron} service, whose value is an
10161 @code{mcron-configuration} object.
10163 This service type can be the target of a service extension that provides
10164 it additional job specifications (@pxref{Service Composition}). In
10165 other words, it is possible to define services that provide additional
10169 @deftp {Data Type} mcron-configuration
10170 Data type representing the configuration of mcron.
10173 @item @code{mcron} (default: @var{mcron2})
10174 The mcron package to use.
10177 This is a list of gexps (@pxref{G-Expressions}), where each gexp
10178 corresponds to an mcron job specification (@pxref{Syntax, mcron job
10179 specifications,, mcron, GNU@tie{}mcron}).
10185 @subsubsection Log Rotation
10188 @cindex log rotation
10190 Log files such as those found in @file{/var/log} tend to grow endlessly,
10191 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
10192 their contents in separate files, possibly compressed. The @code{(gnu
10193 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
10194 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
10196 The example below defines an operating system that provides log rotation
10197 with the default settings, for commonly encountered log files.
10200 (use-modules (guix) (gnu))
10201 (use-service-modules admin mcron)
10202 (use-package-modules base idutils)
10206 (services (cons* (service mcron-service-type)
10207 (service rottlog-service-type)
10211 @defvr {Scheme Variable} rottlog-service-type
10212 This is the type of the Rottlog service, whose value is a
10213 @code{rottlog-configuration} object.
10215 Other services can extend this one with new @code{log-rotation} objects
10216 (see below), thereby augmenting the set of files to be rotated.
10218 This service type can define mcron jobs (@pxref{Scheduled Job
10219 Execution}) to run the rottlog service.
10222 @deftp {Data Type} rottlog-configuration
10223 Data type representing the configuration of rottlog.
10226 @item @code{rottlog} (default: @code{rottlog})
10227 The Rottlog package to use.
10229 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
10230 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
10231 rottlog, GNU Rot[t]log Manual}).
10233 @item @code{rotations} (default: @code{%default-rotations})
10234 A list of @code{log-rotation} objects as defined below.
10237 This is a list of gexps where each gexp corresponds to an mcron job
10238 specification (@pxref{Scheduled Job Execution}).
10242 @deftp {Data Type} log-rotation
10243 Data type representing the rotation of a group of log files.
10245 Taking an example from the Rottlog manual (@pxref{Period Related File
10246 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
10252 (files '("/var/log/apache/*"))
10253 (options '("storedir apache-archives"
10259 The list of fields is as follows:
10262 @item @code{frequency} (default: @code{'weekly})
10263 The log rotation frequency, a symbol.
10266 The list of files or file glob patterns to rotate.
10268 @item @code{options} (default: @code{'()})
10269 The list of rottlog options for this rotation (@pxref{Configuration
10270 parameters,,, rottlog, GNU Rot[t]lg Manual}).
10272 @item @code{post-rotate} (default: @code{#f})
10273 Either @code{#f} or a gexp to execute once the rotation has completed.
10277 @defvr {Scheme Variable} %default-rotations
10278 Specifies weekly rotation of @var{%rotated-files} and
10279 a couple of other files.
10282 @defvr {Scheme Variable} %rotated-files
10283 The list of syslog-controlled files to be rotated. By default it is:
10284 @code{'("/var/log/messages" "/var/log/secure")}.
10287 @node Networking Services
10288 @subsubsection Networking Services
10290 The @code{(gnu services networking)} module provides services to configure
10291 the network interface.
10293 @cindex DHCP, networking service
10294 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
10295 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
10296 Protocol (DHCP) client, on all the non-loopback network interfaces.
10299 @defvr {Scheme Variable} static-networking-service-type
10300 This is the type for statically-configured network interfaces.
10301 @c TODO Document <static-networking> data structures.
10304 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
10305 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
10306 Return a service that starts @var{interface} with address @var{ip}. If
10307 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
10308 it must be a string specifying the default network gateway.
10310 This procedure can be called several times, one for each network
10311 interface of interest. Behind the scenes what it does is extend
10312 @code{static-networking-service-type} with additional network interfaces
10319 @cindex network management
10320 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
10321 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
10322 management daemon that aims to simplify wired and wireless networking.
10324 This service adds the @var{wicd} package to the global profile, providing
10325 several commands to interact with the daemon and configure networking:
10326 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
10327 and @command{wicd-curses} user interfaces.
10330 @cindex NetworkManager
10332 @defvr {Scheme Variable} network-manager-service-type
10333 This is the service type for the
10334 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
10335 service. The value for this service type is a
10336 @code{network-manager-configuration} record.
10338 This service is part of @code{%desktop-services} (@pxref{Desktop
10342 @deftp {Data Type} network-manager-configuration
10343 Data type representing the configuration of NetworkManager.
10346 @item @code{network-manager} (default: @code{network-manager})
10347 The NetworkManager package to use.
10349 @item @code{dns} (default: @code{"default"})
10350 Processing mode for DNS, which affects how NetworkManager uses the
10351 @code{resolv.conf} configuration file.
10355 NetworkManager will update @code{resolv.conf} to reflect the nameservers
10356 provided by currently active connections.
10359 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
10360 using a "split DNS" configuration if you are connected to a VPN, and
10361 then update @code{resolv.conf} to point to the local nameserver.
10364 NetworkManager will not modify @code{resolv.conf}.
10367 @item @code{vpn-plugins} (default: @code{'()})
10368 This is the list of available plugins for virtual private networks
10369 (VPNs). An example of this is the @code{network-manager-openvpn}
10370 package, which allows NetworkManager to manage VPNs @i{via} OpenVPN.
10376 @deffn {Scheme Variable} connman-service-type
10377 This is the service type to run @url{https://01.org/connman,Connman},
10378 a network connection manager.
10380 Its value must be an
10381 @code{connman-configuration} record as in this example:
10384 (service connman-service-type
10385 (connman-configuration
10386 (disable-vpn? #t)))
10389 See below for details about @code{connman-configuration}.
10392 @deftp {Data Type} connman-configuration
10393 Data Type representing the configuration of connman.
10396 @item @code{connman} (default: @var{connman})
10397 The connman package to use.
10399 @item @code{disable-vpn?} (default: @code{#f})
10400 When true, enable connman's vpn plugin.
10404 @cindex WPA Supplicant
10405 @defvr {Scheme Variable} wpa-supplicant-service-type
10406 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
10407 supplicant}, an authentication daemon required to authenticate against
10408 encrypted WiFi or ethernet networks. It is configured to listen for
10411 The value of this service is the @code{wpa-supplicant} package to use.
10412 Thus, it can be instantiated like this:
10415 (use-modules (gnu services networking))
10417 (service wpa-supplicant-service-type)
10422 @cindex real time clock
10423 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
10424 [#:servers @var{%ntp-servers}] @
10425 [#:allow-large-adjustment? #f]
10426 Return a service that runs the daemon from @var{ntp}, the
10427 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
10428 keep the system clock synchronized with that of @var{servers}.
10429 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
10430 make an initial adjustment of more than 1,000 seconds.
10433 @defvr {Scheme Variable} %ntp-servers
10434 List of host names used as the default NTP servers.
10438 @deffn {Scheme variable} inetd-service-type
10439 This service runs the @command{inetd} (@pxref{inetd invocation,,,
10440 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
10441 connections on internet sockets, and lazily starts the specified server
10442 program when a connection is made on one of these sockets.
10444 The value of this service is an @code{inetd-configuration} object. The
10445 following example configures the @command{inetd} daemon to provide the
10446 built-in @command{echo} service, as well as an smtp service which
10447 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
10448 gateway @code{hostname}:
10453 (inetd-configuration
10457 (socket-type 'stream)
10464 (socket-type 'stream)
10468 (program (file-append openssh "/bin/ssh"))
10470 '("ssh" "-qT" "-i" "/path/to/ssh_key"
10471 "-W" "smtp-server:25" "user@@hostname")))))
10474 See below for more details about @code{inetd-configuration}.
10477 @deftp {Data Type} inetd-configuration
10478 Data type representing the configuration of @command{inetd}.
10481 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
10482 The @command{inetd} executable to use.
10484 @item @code{entries} (default: @code{'()})
10485 A list of @command{inetd} service entries. Each entry should be created
10486 by the @code{inetd-entry} constructor.
10490 @deftp {Data Type} inetd-entry
10491 Data type representing an entry in the @command{inetd} configuration.
10492 Each entry corresponds to a socket where @command{inetd} will listen for
10496 @item @code{node} (default: @code{#f})
10497 Optional string, a comma-separated list of local addresses
10498 @command{inetd} should use when listening for this service.
10499 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
10500 description of all options.
10502 A string, the name must correspond to an entry in @code{/etc/services}.
10503 @item @code{socket-type}
10504 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
10506 @item @code{protocol}
10507 A string, must correspond to an entry in @code{/etc/protocols}.
10508 @item @code{wait?} (default: @code{#t})
10509 Whether @command{inetd} should wait for the server to exit before
10510 listening to new service requests.
10512 A string containing the user (and, optionally, group) name of the user
10513 as whom the server should run. The group name can be specified in a
10514 suffix, separated by a colon or period, i.e. @code{"user"},
10515 @code{"user:group"} or @code{"user.group"}.
10516 @item @code{program} (default: @code{"internal"})
10517 The server program which will serve the requests, or @code{"internal"}
10518 if @command{inetd} should use a built-in service.
10519 @item @code{arguments} (default: @code{'()})
10520 A list strings or file-like objects, which are the server program's
10521 arguments, starting with the zeroth argument, i.e. the name of the
10522 program itself. For @command{inetd}'s internal services, this entry
10523 must be @code{'()} or @code{'("internal")}.
10526 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
10527 detailed discussion of each configuration field.
10531 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
10532 Return a service to run the @uref{https://torproject.org, Tor} anonymous
10535 The daemon runs as the @code{tor} unprivileged user. It is passed
10536 @var{config-file}, a file-like object, with an additional @code{User tor} line
10537 and lines for hidden services added via @code{tor-hidden-service}. Run
10538 @command{man tor} for information about the configuration file.
10541 @cindex hidden service
10542 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
10543 Define a new Tor @dfn{hidden service} called @var{name} and implementing
10544 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
10547 '((22 "127.0.0.1:22")
10548 (80 "127.0.0.1:8080"))
10551 In this example, port 22 of the hidden service is mapped to local port 22, and
10552 port 80 is mapped to local port 8080.
10554 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
10555 the @file{hostname} file contains the @code{.onion} host name for the hidden
10558 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
10559 project's documentation} for more information.
10562 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
10563 [#:interface "127.0.0.1"] [#:port 6667] @
10564 [#:extra-settings ""]
10565 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
10566 acts as a gateway between IRC and chat networks.
10568 The daemon will listen to the interface corresponding to the IP address
10569 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
10570 local clients can connect, whereas @code{0.0.0.0} means that connections can
10571 come from any networking interface.
10573 In addition, @var{extra-settings} specifies a string to append to the
10574 configuration file.
10577 The @code{(gnu services rsync)} module provides the following services:
10579 You might want an rsync daemon if you have files that you want available
10580 so anyone (or just yourself) can download existing files or upload new
10583 @deffn {Scheme Variable} rsync-service-type
10584 This is the type for the @uref{https://rsync.samba.org, rsync} rsync daemon,
10585 @command{rsync-configuration} record as in this example:
10588 (service rsync-service-type)
10591 See below for details about @code{rsync-configuration}.
10594 @deftp {Data Type} rsync-configuration
10595 Data type representing the configuration for @code{rsync-service}.
10598 @item @code{package} (default: @var{rsync})
10599 @code{rsync} package to use.
10601 @item @code{port-number} (default: @code{873})
10602 TCP port on which @command{rsync} listens for incoming connections. If port
10603 is less than @code{1024} @command{rsync} needs to be started as the
10604 @code{root} user and group.
10606 @item @code{pid-file} (default: @code{"/var/run/rsyncd/rsyncd.pid"})
10607 Name of the file where @command{rsync} writes its PID.
10609 @item @code{lock-file} (default: @code{"/var/run/rsyncd/rsyncd.lock"})
10610 Name of the file where @command{rsync} writes its lock file.
10612 @item @code{log-file} (default: @code{"/var/log/rsyncd.log"})
10613 Name of the file where @command{rsync} writes its log file.
10615 @item @code{use-chroot?} (default: @var{#t})
10616 Whether to use chroot for @command{rsync} shared directory.
10618 @item @code{share-path} (default: @file{/srv/rsync})
10619 Location of the @command{rsync} shared directory.
10621 @item @code{share-comment} (default: @code{"Rsync share"})
10622 Comment of the @command{rsync} shared directory.
10624 @item @code{read-only?} (default: @var{#f})
10625 Read-write permissions to shared directory.
10627 @item @code{timeout} (default: @code{300})
10628 I/O timeout in seconds.
10630 @item @code{user} (default: @var{"root"})
10631 Owner of the @code{rsync} process.
10633 @item @code{group} (default: @var{"root"})
10634 Group of the @code{rsync} process.
10636 @item @code{uid} (default: @var{"rsyncd"})
10637 User name or user ID that file transfers to and from that module should take
10638 place as when the daemon was run as @code{root}.
10640 @item @code{gid} (default: @var{"rsyncd"})
10641 Group name or group ID that will be used when accessing the module.
10646 Furthermore, @code{(gnu services ssh)} provides the following services.
10650 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10651 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10652 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10653 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10654 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10655 [#:public-key-authentication? #t] [#:initialize? #t]
10656 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10657 @var{host-key} must designate a file containing the host key, and readable
10660 When @var{daemonic?} is true, @command{lshd} will detach from the
10661 controlling terminal and log its output to syslogd, unless one sets
10662 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10663 depend on existence of syslogd service. When @var{pid-file?} is true,
10664 @command{lshd} writes its PID to the file called @var{pid-file}.
10666 When @var{initialize?} is true, automatically create the seed and host key
10667 upon service activation if they do not exist yet. This may take long and
10668 require interaction.
10670 When @var{initialize?} is false, it is up to the user to initialize the
10671 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10672 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10673 basics,,, lsh, LSH Manual}).
10675 When @var{interfaces} is empty, lshd listens for connections on all the
10676 network interfaces; otherwise, @var{interfaces} must be a list of host names
10679 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10680 passwords, and @var{root-login?} specifies whether to accept log-ins as
10683 The other options should be self-descriptive.
10688 @deffn {Scheme Variable} openssh-service-type
10689 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10690 shell daemon, @command{sshd}. Its value must be an
10691 @code{openssh-configuration} record as in this example:
10694 (service openssh-service-type
10695 (openssh-configuration
10696 (x11-forwarding? #t)
10697 (permit-root-login 'without-password)
10699 `(("alice" ,(local-file "alice.pub"))
10700 ("bob" ,(local-file "bob.pub"))))))
10703 See below for details about @code{openssh-configuration}.
10705 This service can be extended with extra authorized keys, as in this
10709 (service-extension openssh-service-type
10710 (const `(("charlie"
10711 ,(local-file "charlie.pub")))))
10715 @deftp {Data Type} openssh-configuration
10716 This is the configuration record for OpenSSH's @command{sshd}.
10719 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10720 Name of the file where @command{sshd} writes its PID.
10722 @item @code{port-number} (default: @code{22})
10723 TCP port on which @command{sshd} listens for incoming connections.
10725 @item @code{permit-root-login} (default: @code{#f})
10726 This field determines whether and when to allow logins as root. If
10727 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10728 If it's the symbol @code{'without-password}, then root logins are
10729 permitted but not with password-based authentication.
10731 @item @code{allow-empty-passwords?} (default: @code{#f})
10732 When true, users with empty passwords may log in. When false, they may
10735 @item @code{password-authentication?} (default: @code{#t})
10736 When true, users may log in with their password. When false, they have
10737 other authentication methods.
10739 @item @code{public-key-authentication?} (default: @code{#t})
10740 When true, users may log in using public key authentication. When
10741 false, users have to use other authentication method.
10743 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10744 This is used only by protocol version 2.
10746 @item @code{x11-forwarding?} (default: @code{#f})
10747 When true, forwarding of X11 graphical client connections is
10748 enabled---in other words, @command{ssh} options @option{-X} and
10749 @option{-Y} will work.
10751 @item @code{challenge-response-authentication?} (default: @code{#f})
10752 Specifies whether challenge response authentication is allowed (e.g. via
10755 @item @code{use-pam?} (default: @code{#t})
10756 Enables the Pluggable Authentication Module interface. If set to
10757 @code{#t}, this will enable PAM authentication using
10758 @code{challenge-response-authentication?} and
10759 @code{password-authentication?}, in addition to PAM account and session
10760 module processing for all authentication types.
10762 Because PAM challenge response authentication usually serves an
10763 equivalent role to password authentication, you should disable either
10764 @code{challenge-response-authentication?} or
10765 @code{password-authentication?}.
10767 @item @code{print-last-log?} (default: @code{#t})
10768 Specifies whether @command{sshd} should print the date and time of the
10769 last user login when a user logs in interactively.
10771 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10772 Configures external subsystems (e.g. file transfer daemon).
10774 This is a list of two-element lists, each of which containing the
10775 subsystem name and a command (with optional arguments) to execute upon
10778 The command @command{internal-sftp} implements an in-process SFTP
10779 server. Alternately, one can specify the @command{sftp-server} command:
10781 (service openssh-service-type
10782 (openssh-configuration
10784 `(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10787 @item @code{authorized-keys} (default: @code{'()})
10788 @cindex authorized keys, SSH
10789 @cindex SSH authorized keys
10790 This is the list of authorized keys. Each element of the list is a user
10791 name followed by one or more file-like objects that represent SSH public
10795 (openssh-configuration
10797 `(("rekado" ,(local-file "rekado.pub"))
10798 ("chris" ,(local-file "chris.pub"))
10799 ("root" ,(local-file "rekado.pub") ,(local-file "chris.pub")))))
10803 registers the specified public keys for user accounts @code{rekado},
10804 @code{chris}, and @code{root}.
10806 Additional authorized keys can be specified @i{via}
10807 @code{service-extension}.
10809 Note that this does @emph{not} interfere with the use of
10810 @file{~/.ssh/authorized_keys}.
10814 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10815 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10816 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10819 For example, to specify a Dropbear service listening on port 1234, add
10820 this call to the operating system's @code{services} field:
10823 (dropbear-service (dropbear-configuration
10824 (port-number 1234)))
10828 @deftp {Data Type} dropbear-configuration
10829 This data type represents the configuration of a Dropbear SSH daemon.
10832 @item @code{dropbear} (default: @var{dropbear})
10833 The Dropbear package to use.
10835 @item @code{port-number} (default: 22)
10836 The TCP port where the daemon waits for incoming connections.
10838 @item @code{syslog-output?} (default: @code{#t})
10839 Whether to enable syslog output.
10841 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10842 File name of the daemon's PID file.
10844 @item @code{root-login?} (default: @code{#f})
10845 Whether to allow @code{root} logins.
10847 @item @code{allow-empty-passwords?} (default: @code{#f})
10848 Whether to allow empty passwords.
10850 @item @code{password-authentication?} (default: @code{#t})
10851 Whether to enable password-based authentication.
10855 @defvr {Scheme Variable} %facebook-host-aliases
10856 This variable contains a string for use in @file{/etc/hosts}
10857 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10858 line contains a entry that maps a known server name of the Facebook
10859 on-line service---e.g., @code{www.facebook.com}---to the local
10860 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10862 This variable is typically used in the @code{hosts-file} field of an
10863 @code{operating-system} declaration (@pxref{operating-system Reference,
10864 @file{/etc/hosts}}):
10867 (use-modules (gnu) (guix))
10870 (host-name "mymachine")
10873 ;; Create a /etc/hosts file with aliases for "localhost"
10874 ;; and "mymachine", as well as for Facebook servers.
10875 (plain-file "hosts"
10876 (string-append (local-host-aliases host-name)
10877 %facebook-host-aliases))))
10880 This mechanism can prevent programs running locally, such as Web
10881 browsers, from accessing Facebook.
10884 The @code{(gnu services avahi)} provides the following definition.
10886 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10887 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10888 [#:ipv6? #t] [#:wide-area? #f] @
10889 [#:domains-to-browse '()] [#:debug? #f]
10890 Return a service that runs @command{avahi-daemon}, a system-wide
10891 mDNS/DNS-SD responder that allows for service discovery and
10892 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10893 extends the name service cache daemon (nscd) so that it can resolve
10894 @code{.local} host names using
10895 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10896 add the @var{avahi} package to the system profile so that commands such as
10897 @command{avahi-browse} are directly usable.
10899 If @var{host-name} is different from @code{#f}, use that as the host name to
10900 publish for this machine; otherwise, use the machine's actual host name.
10902 When @var{publish?} is true, publishing of host names and services is allowed;
10903 in particular, avahi-daemon will publish the machine's host name and IP
10904 address via mDNS on the local network.
10906 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10908 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10912 @deffn {Scheme Variable} openvswitch-service-type
10913 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10914 service, whose value should be an @code{openvswitch-configuration}
10918 @deftp {Data Type} openvswitch-configuration
10919 Data type representing the configuration of Open vSwitch, a multilayer
10920 virtual switch which is designed to enable massive network automation
10921 through programmatic extension.
10924 @item @code{package} (default: @var{openvswitch})
10925 Package object of the Open vSwitch.
10931 @subsubsection X Window
10934 @cindex X Window System
10935 Support for the X Window graphical display system---specifically
10936 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10937 there is no @code{xorg-service} procedure. Instead, the X server is
10938 started by the @dfn{login manager}, currently SLiM.
10940 @deftp {Data Type} sddm-configuration
10941 This is the data type representing the sddm service configuration.
10944 @item @code{display-server} (default: "x11")
10945 Select display server to use for the greeter. Valid values are "x11"
10948 @item @code{numlock} (default: "on")
10949 Valid values are "on", "off" or "none".
10951 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10952 Command to run when halting.
10954 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10955 Command to run when rebooting.
10957 @item @code{theme} (default "maldives")
10958 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10960 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10961 Directory to look for themes.
10963 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10964 Directory to look for faces.
10966 @item @code{default-path} (default "/run/current-system/profile/bin")
10967 Default PATH to use.
10969 @item @code{minimum-uid} (default 1000)
10970 Minimum UID to display in SDDM.
10972 @item @code{maximum-uid} (default 2000)
10973 Maximum UID to display in SDDM
10975 @item @code{remember-last-user?} (default #t)
10976 Remember last user.
10978 @item @code{remember-last-session?} (default #t)
10979 Remember last session.
10981 @item @code{hide-users} (default "")
10982 Usernames to hide from SDDM greeter.
10984 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10985 Users with shells listed will be hidden from the SDDM greeter.
10987 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10988 Script to run before starting a wayland session.
10990 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10991 Directory to look for desktop files starting wayland sessions.
10993 @item @code{xorg-server-path} (default @code{xorg-start-command})
10994 Path to xorg-server.
10996 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10999 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
11002 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
11003 Script to run after starting xorg-server.
11005 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
11006 Script to run before stopping xorg-server.
11008 @item @code{xsession-command} (default: @code{xinitr })
11009 Script to run before starting a X session.
11011 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
11012 Directory to look for desktop files starting X sessions.
11014 @item @code{minimum-vt} (default: 7)
11017 @item @code{xserver-arguments} (default "-nolisten tcp")
11018 Arguments to pass to xorg-server.
11020 @item @code{auto-login-user} (default "")
11021 User to use for auto-login.
11023 @item @code{auto-login-session} (default "")
11024 Desktop file to use for auto-login.
11026 @item @code{relogin?} (default #f)
11027 Relogin after logout.
11032 @cindex login manager
11033 @deffn {Scheme Procedure} sddm-service config
11034 Return a service that spawns the SDDM graphical login manager for config of
11035 type @code{<sddm-configuration>}.
11038 (sddm-service (sddm-configuration
11039 (auto-login-user "Alice")
11040 (auto-login-session "xfce.desktop")))
11044 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
11045 [#:auto-login? #f] [#:default-user ""] [#:startx] @
11046 [#:theme @var{%default-slim-theme}] @
11047 [#:theme-name @var{%default-slim-theme-name}]
11048 Return a service that spawns the SLiM graphical login manager, which in
11049 turn starts the X display server with @var{startx}, a command as returned by
11050 @code{xorg-start-command}.
11054 SLiM automatically looks for session types described by the @file{.desktop}
11055 files in @file{/run/current-system/profile/share/xsessions} and allows users
11056 to choose a session from the log-in screen using @kbd{F1}. Packages such as
11057 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
11058 adding them to the system-wide set of packages automatically makes them
11059 available at the log-in screen.
11061 In addition, @file{~/.xsession} files are honored. When available,
11062 @file{~/.xsession} must be an executable that starts a window manager
11063 and/or other X clients.
11065 When @var{allow-empty-passwords?} is true, allow logins with an empty
11066 password. When @var{auto-login?} is true, log in automatically as
11067 @var{default-user}.
11069 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
11070 @var{theme} must be a gexp denoting the name of a directory containing the
11071 theme to use. In that case, @var{theme-name} specifies the name of the
11075 @defvr {Scheme Variable} %default-theme
11076 @defvrx {Scheme Variable} %default-theme-name
11077 The G-Expression denoting the default SLiM theme and its name.
11080 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
11081 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
11082 Return a derivation that builds a @var{guile} script to start the X server
11083 from @var{xorg-server}. @var{configuration-file} is the server configuration
11084 file or a derivation that builds it; when omitted, the result of
11085 @code{xorg-configuration-file} is used.
11087 Usually the X server is started by a login manager.
11090 @deffn {Scheme Procedure} xorg-configuration-file @
11091 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
11092 Return a configuration file for the Xorg server containing search paths for
11093 all the common drivers.
11095 @var{drivers} must be either the empty list, in which case Xorg chooses a
11096 graphics driver automatically, or a list of driver names that will be tried in
11097 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
11099 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
11100 appropriate screen resolution; otherwise, it must be a list of
11101 resolutions---e.g., @code{((1024 768) (640 480))}.
11103 Last, @var{extra-config} is a list of strings or objects appended to the
11104 @code{text-file*} argument list. It is used to pass extra text to be added
11105 verbatim to the configuration file.
11108 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
11109 Add @var{package}, a package for a screen-locker or screen-saver whose
11110 command is @var{program}, to the set of setuid programs and add a PAM entry
11111 for it. For example:
11114 (screen-locker-service xlockmore "xlock")
11117 makes the good ol' XlockMore usable.
11121 @node Printing Services
11122 @subsubsection Printing Services
11124 @cindex printer support with CUPS
11125 The @code{(gnu services cups)} module provides a Guix service definition
11126 for the CUPS printing service. To add printer support to a GuixSD
11127 system, add a @code{cups-service} to the operating system definition:
11129 @deffn {Scheme Variable} cups-service-type
11130 The service type for the CUPS print server. Its value should be a valid
11131 CUPS configuration (see below). To use the default settings, simply
11134 (service cups-service-type)
11138 The CUPS configuration controls the basic things about your CUPS
11139 installation: what interfaces it listens on, what to do if a print job
11140 fails, how much logging to do, and so on. To actually add a printer,
11141 you have to visit the @url{http://localhost:631} URL, or use a tool such
11142 as GNOME's printer configuration services. By default, configuring a
11143 CUPS service will generate a self-signed certificate if needed, for
11144 secure connections to the print server.
11146 Suppose you want to enable the Web interface of CUPS and also add
11147 support for HP printers @i{via} the @code{hplip} package. You can do
11148 that directly, like this (you need to use the @code{(gnu packages cups)}
11152 (service cups-service-type
11153 (cups-configuration
11154 (web-interface? #t)
11156 (list cups-filters hplip))))
11159 The available configuration parameters follow. Each parameter
11160 definition is preceded by its type; for example, @samp{string-list foo}
11161 indicates that the @code{foo} parameter should be specified as a list of
11162 strings. There is also a way to specify the configuration as a string,
11163 if you have an old @code{cupsd.conf} file that you want to port over
11164 from some other system; see the end for more details.
11166 @c The following documentation was initially generated by
11167 @c (generate-documentation) in (gnu services cups). Manually maintained
11168 @c documentation is better, so we shouldn't hesitate to edit below as
11169 @c needed. However if the change you want to make to this documentation
11170 @c can be done in an automated way, it's probably easier to change
11171 @c (generate-documentation) than to make it below and have to deal with
11172 @c the churn as CUPS updates.
11175 Available @code{cups-configuration} fields are:
11177 @deftypevr {@code{cups-configuration} parameter} package cups
11181 @deftypevr {@code{cups-configuration} parameter} package-list extensions
11182 Drivers and other extensions to the CUPS package.
11185 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
11186 Configuration of where to write logs, what directories to use for print
11187 spools, and related privileged configuration parameters.
11189 Available @code{files-configuration} fields are:
11191 @deftypevr {@code{files-configuration} parameter} log-location access-log
11192 Defines the access log filename. Specifying a blank filename disables
11193 access log generation. The value @code{stderr} causes log entries to be
11194 sent to the standard error file when the scheduler is running in the
11195 foreground, or to the system log daemon when run in the background. The
11196 value @code{syslog} causes log entries to be sent to the system log
11197 daemon. The server name may be included in filenames using the string
11198 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
11200 Defaults to @samp{"/var/log/cups/access_log"}.
11203 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
11204 Where CUPS should cache data.
11206 Defaults to @samp{"/var/cache/cups"}.
11209 @deftypevr {@code{files-configuration} parameter} string config-file-perm
11210 Specifies the permissions for all configuration files that the scheduler
11213 Note that the permissions for the printers.conf file are currently
11214 masked to only allow access from the scheduler user (typically root).
11215 This is done because printer device URIs sometimes contain sensitive
11216 authentication information that should not be generally known on the
11217 system. There is no way to disable this security feature.
11219 Defaults to @samp{"0640"}.
11222 @deftypevr {@code{files-configuration} parameter} log-location error-log
11223 Defines the error log filename. Specifying a blank filename disables
11224 access log generation. The value @code{stderr} causes log entries to be
11225 sent to the standard error file when the scheduler is running in the
11226 foreground, or to the system log daemon when run in the background. The
11227 value @code{syslog} causes log entries to be sent to the system log
11228 daemon. The server name may be included in filenames using the string
11229 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
11231 Defaults to @samp{"/var/log/cups/error_log"}.
11234 @deftypevr {@code{files-configuration} parameter} string fatal-errors
11235 Specifies which errors are fatal, causing the scheduler to exit. The
11240 No errors are fatal.
11243 All of the errors below are fatal.
11246 Browsing initialization errors are fatal, for example failed connections
11247 to the DNS-SD daemon.
11250 Configuration file syntax errors are fatal.
11253 Listen or Port errors are fatal, except for IPv6 failures on the
11254 loopback or @code{any} addresses.
11257 Log file creation or write errors are fatal.
11260 Bad startup file permissions are fatal, for example shared TLS
11261 certificate and key files with world-read permissions.
11264 Defaults to @samp{"all -browse"}.
11267 @deftypevr {@code{files-configuration} parameter} boolean file-device?
11268 Specifies whether the file pseudo-device can be used for new printer
11269 queues. The URI @uref{file:///dev/null} is always allowed.
11271 Defaults to @samp{#f}.
11274 @deftypevr {@code{files-configuration} parameter} string group
11275 Specifies the group name or ID that will be used when executing external
11278 Defaults to @samp{"lp"}.
11281 @deftypevr {@code{files-configuration} parameter} string log-file-perm
11282 Specifies the permissions for all log files that the scheduler writes.
11284 Defaults to @samp{"0644"}.
11287 @deftypevr {@code{files-configuration} parameter} log-location page-log
11288 Defines the page log filename. Specifying a blank filename disables
11289 access log generation. The value @code{stderr} causes log entries to be
11290 sent to the standard error file when the scheduler is running in the
11291 foreground, or to the system log daemon when run in the background. The
11292 value @code{syslog} causes log entries to be sent to the system log
11293 daemon. The server name may be included in filenames using the string
11294 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
11296 Defaults to @samp{"/var/log/cups/page_log"}.
11299 @deftypevr {@code{files-configuration} parameter} string remote-root
11300 Specifies the username that is associated with unauthenticated accesses
11301 by clients claiming to be the root user. The default is @code{remroot}.
11303 Defaults to @samp{"remroot"}.
11306 @deftypevr {@code{files-configuration} parameter} file-name request-root
11307 Specifies the directory that contains print jobs and other HTTP request
11310 Defaults to @samp{"/var/spool/cups"}.
11313 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
11314 Specifies the level of security sandboxing that is applied to print
11315 filters, backends, and other child processes of the scheduler; either
11316 @code{relaxed} or @code{strict}. This directive is currently only
11317 used/supported on macOS.
11319 Defaults to @samp{strict}.
11322 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
11323 Specifies the location of TLS certificates and private keys. CUPS will
11324 look for public and private keys in this directory: a @code{.crt} files
11325 for PEM-encoded certificates and corresponding @code{.key} files for
11326 PEM-encoded private keys.
11328 Defaults to @samp{"/etc/cups/ssl"}.
11331 @deftypevr {@code{files-configuration} parameter} file-name server-root
11332 Specifies the directory containing the server configuration files.
11334 Defaults to @samp{"/etc/cups"}.
11337 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
11338 Specifies whether the scheduler calls fsync(2) after writing
11339 configuration or state files.
11341 Defaults to @samp{#f}.
11344 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
11345 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
11348 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
11349 Specifies the directory where temporary files are stored.
11351 Defaults to @samp{"/var/spool/cups/tmp"}.
11354 @deftypevr {@code{files-configuration} parameter} string user
11355 Specifies the user name or ID that is used when running external
11358 Defaults to @samp{"lp"}.
11362 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
11363 Specifies the logging level for the AccessLog file. The @code{config}
11364 level logs when printers and classes are added, deleted, or modified and
11365 when configuration files are accessed or updated. The @code{actions}
11366 level logs when print jobs are submitted, held, released, modified, or
11367 canceled, and any of the conditions for @code{config}. The @code{all}
11368 level logs all requests.
11370 Defaults to @samp{actions}.
11373 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
11374 Specifies whether to purge job history data automatically when it is no
11375 longer required for quotas.
11377 Defaults to @samp{#f}.
11380 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
11381 Specifies which protocols to use for local printer sharing.
11383 Defaults to @samp{dnssd}.
11386 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
11387 Specifies whether the CUPS web interface is advertised.
11389 Defaults to @samp{#f}.
11392 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
11393 Specifies whether shared printers are advertised.
11395 Defaults to @samp{#f}.
11398 @deftypevr {@code{cups-configuration} parameter} string classification
11399 Specifies the security classification of the server. Any valid banner
11400 name can be used, including "classified", "confidential", "secret",
11401 "topsecret", and "unclassified", or the banner can be omitted to disable
11402 secure printing functions.
11404 Defaults to @samp{""}.
11407 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
11408 Specifies whether users may override the classification (cover page) of
11409 individual print jobs using the @code{job-sheets} option.
11411 Defaults to @samp{#f}.
11414 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
11415 Specifies the default type of authentication to use.
11417 Defaults to @samp{Basic}.
11420 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
11421 Specifies whether encryption will be used for authenticated requests.
11423 Defaults to @samp{Required}.
11426 @deftypevr {@code{cups-configuration} parameter} string default-language
11427 Specifies the default language to use for text and web content.
11429 Defaults to @samp{"en"}.
11432 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
11433 Specifies the default paper size for new print queues. @samp{"Auto"}
11434 uses a locale-specific default, while @samp{"None"} specifies there is
11435 no default paper size. Specific size names are typically
11436 @samp{"Letter"} or @samp{"A4"}.
11438 Defaults to @samp{"Auto"}.
11441 @deftypevr {@code{cups-configuration} parameter} string default-policy
11442 Specifies the default access policy to use.
11444 Defaults to @samp{"default"}.
11447 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
11448 Specifies whether local printers are shared by default.
11450 Defaults to @samp{#t}.
11453 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
11454 Specifies the delay for updating of configuration and state files, in
11455 seconds. A value of 0 causes the update to happen as soon as possible,
11456 typically within a few milliseconds.
11458 Defaults to @samp{30}.
11461 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
11462 Specifies what to do when an error occurs. Possible values are
11463 @code{abort-job}, which will discard the failed print job;
11464 @code{retry-job}, which will retry the job at a later time;
11465 @code{retry-this-job}, which retries the failed job immediately; and
11466 @code{stop-printer}, which stops the printer.
11468 Defaults to @samp{stop-printer}.
11471 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
11472 Specifies the maximum cost of filters that are run concurrently, which
11473 can be used to minimize disk, memory, and CPU resource problems. A
11474 limit of 0 disables filter limiting. An average print to a
11475 non-PostScript printer needs a filter limit of about 200. A PostScript
11476 printer needs about half that (100). Setting the limit below these
11477 thresholds will effectively limit the scheduler to printing a single job
11480 Defaults to @samp{0}.
11483 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
11484 Specifies the scheduling priority of filters that are run to print a
11485 job. The nice value ranges from 0, the highest priority, to 19, the
11488 Defaults to @samp{0}.
11491 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
11492 Specifies whether to do reverse lookups on connecting clients. The
11493 @code{double} setting causes @code{cupsd} to verify that the hostname
11494 resolved from the address matches one of the addresses returned for that
11495 hostname. Double lookups also prevent clients with unregistered
11496 addresses from connecting to your server. Only set this option to
11497 @code{#t} or @code{double} if absolutely required.
11499 Defaults to @samp{#f}.
11502 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
11503 Specifies the number of seconds to wait before killing the filters and
11504 backend associated with a canceled or held job.
11506 Defaults to @samp{30}.
11509 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
11510 Specifies the interval between retries of jobs in seconds. This is
11511 typically used for fax queues but can also be used with normal print
11512 queues whose error policy is @code{retry-job} or
11513 @code{retry-current-job}.
11515 Defaults to @samp{30}.
11518 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
11519 Specifies the number of retries that are done for jobs. This is
11520 typically used for fax queues but can also be used with normal print
11521 queues whose error policy is @code{retry-job} or
11522 @code{retry-current-job}.
11524 Defaults to @samp{5}.
11527 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
11528 Specifies whether to support HTTP keep-alive connections.
11530 Defaults to @samp{#t}.
11533 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
11534 Specifies how long an idle client connection remains open, in seconds.
11536 Defaults to @samp{30}.
11539 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
11540 Specifies the maximum size of print files, IPP requests, and HTML form
11541 data. A limit of 0 disables the limit check.
11543 Defaults to @samp{0}.
11546 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
11547 Listens on the specified interfaces for connections. Valid values are
11548 of the form @var{address}:@var{port}, where @var{address} is either an
11549 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
11550 indicate all addresses. Values can also be file names of local UNIX
11551 domain sockets. The Listen directive is similar to the Port directive
11552 but allows you to restrict access to specific interfaces or networks.
11555 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
11556 Specifies the number of pending connections that will be allowed. This
11557 normally only affects very busy servers that have reached the MaxClients
11558 limit, but can also be triggered by large numbers of simultaneous
11559 connections. When the limit is reached, the operating system will
11560 refuse additional connections until the scheduler can accept the pending
11563 Defaults to @samp{128}.
11566 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
11567 Specifies a set of additional access controls.
11569 Available @code{location-access-controls} fields are:
11571 @deftypevr {@code{location-access-controls} parameter} file-name path
11572 Specifies the URI path to which the access control applies.
11575 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
11576 Access controls for all access to this path, in the same format as the
11577 @code{access-controls} of @code{operation-access-control}.
11579 Defaults to @samp{()}.
11582 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
11583 Access controls for method-specific access to this path.
11585 Defaults to @samp{()}.
11587 Available @code{method-access-controls} fields are:
11589 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
11590 If @code{#t}, apply access controls to all methods except the listed
11591 methods. Otherwise apply to only the listed methods.
11593 Defaults to @samp{#f}.
11596 @deftypevr {@code{method-access-controls} parameter} method-list methods
11597 Methods to which this access control applies.
11599 Defaults to @samp{()}.
11602 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
11603 Access control directives, as a list of strings. Each string should be
11604 one directive, such as "Order allow,deny".
11606 Defaults to @samp{()}.
11611 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
11612 Specifies the number of debugging messages that are retained for logging
11613 if an error occurs in a print job. Debug messages are logged regardless
11614 of the LogLevel setting.
11616 Defaults to @samp{100}.
11619 @deftypevr {@code{cups-configuration} parameter} log-level log-level
11620 Specifies the level of logging for the ErrorLog file. The value
11621 @code{none} stops all logging while @code{debug2} logs everything.
11623 Defaults to @samp{info}.
11626 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
11627 Specifies the format of the date and time in the log files. The value
11628 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
11630 Defaults to @samp{standard}.
11633 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
11634 Specifies the maximum number of simultaneous clients that are allowed by
11637 Defaults to @samp{100}.
11640 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
11641 Specifies the maximum number of simultaneous clients that are allowed
11642 from a single address.
11644 Defaults to @samp{100}.
11647 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
11648 Specifies the maximum number of copies that a user can print of each
11651 Defaults to @samp{9999}.
11654 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
11655 Specifies the maximum time a job may remain in the @code{indefinite}
11656 hold state before it is canceled. A value of 0 disables cancellation of
11659 Defaults to @samp{0}.
11662 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
11663 Specifies the maximum number of simultaneous jobs that are allowed. Set
11664 to 0 to allow an unlimited number of jobs.
11666 Defaults to @samp{500}.
11669 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
11670 Specifies the maximum number of simultaneous jobs that are allowed per
11671 printer. A value of 0 allows up to MaxJobs jobs per printer.
11673 Defaults to @samp{0}.
11676 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
11677 Specifies the maximum number of simultaneous jobs that are allowed per
11678 user. A value of 0 allows up to MaxJobs jobs per user.
11680 Defaults to @samp{0}.
11683 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11684 Specifies the maximum time a job may take to print before it is
11685 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11687 Defaults to @samp{10800}.
11690 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11691 Specifies the maximum size of the log files before they are rotated, in
11692 bytes. The value 0 disables log rotation.
11694 Defaults to @samp{1048576}.
11697 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11698 Specifies the maximum amount of time to allow between files in a
11699 multiple file print job, in seconds.
11701 Defaults to @samp{300}.
11704 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11705 Specifies the format of PageLog lines. Sequences beginning with percent
11706 (@samp{%}) characters are replaced with the corresponding information,
11707 while all other characters are copied literally. The following percent
11708 sequences are recognized:
11712 insert a single percent character
11715 insert the value of the specified IPP attribute
11718 insert the number of copies for the current page
11721 insert the current page number
11724 insert the current date and time in common log format
11730 insert the printer name
11733 insert the username
11736 A value of the empty string disables page logging. The string @code{%p
11737 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11738 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11741 Defaults to @samp{""}.
11744 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11745 Passes the specified environment variable(s) to child processes; a list
11748 Defaults to @samp{()}.
11751 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11752 Specifies named access control policies.
11754 Available @code{policy-configuration} fields are:
11756 @deftypevr {@code{policy-configuration} parameter} string name
11757 Name of the policy.
11760 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11761 Specifies an access list for a job's private values. @code{@@ACL} maps
11762 to the printer's requesting-user-name-allowed or
11763 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11764 owner. @code{@@SYSTEM} maps to the groups listed for the
11765 @code{system-group} field of the @code{files-config} configuration,
11766 which is reified into the @code{cups-files.conf(5)} file. Other
11767 possible elements of the access list include specific user names, and
11768 @code{@@@var{group}} to indicate members of a specific group. The
11769 access list may also be simply @code{all} or @code{default}.
11771 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11774 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11775 Specifies the list of job values to make private, or @code{all},
11776 @code{default}, or @code{none}.
11778 Defaults to @samp{"job-name job-originating-host-name
11779 job-originating-user-name phone"}.
11782 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11783 Specifies an access list for a subscription's private values.
11784 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11785 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11786 owner. @code{@@SYSTEM} maps to the groups listed for the
11787 @code{system-group} field of the @code{files-config} configuration,
11788 which is reified into the @code{cups-files.conf(5)} file. Other
11789 possible elements of the access list include specific user names, and
11790 @code{@@@var{group}} to indicate members of a specific group. The
11791 access list may also be simply @code{all} or @code{default}.
11793 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11796 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11797 Specifies the list of job values to make private, or @code{all},
11798 @code{default}, or @code{none}.
11800 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11801 notify-subscriber-user-name notify-user-data"}.
11804 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11805 Access control by IPP operation.
11807 Defaults to @samp{()}.
11811 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11812 Specifies whether job files (documents) are preserved after a job is
11813 printed. If a numeric value is specified, job files are preserved for
11814 the indicated number of seconds after printing. Otherwise a boolean
11815 value applies indefinitely.
11817 Defaults to @samp{86400}.
11820 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11821 Specifies whether the job history is preserved after a job is printed.
11822 If a numeric value is specified, the job history is preserved for the
11823 indicated number of seconds after printing. If @code{#t}, the job
11824 history is preserved until the MaxJobs limit is reached.
11826 Defaults to @samp{#t}.
11829 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11830 Specifies the amount of time to wait for job completion before
11831 restarting the scheduler.
11833 Defaults to @samp{30}.
11836 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11837 Specifies the maximum amount of memory to use when converting documents
11838 into bitmaps for a printer.
11840 Defaults to @samp{"128m"}.
11843 @deftypevr {@code{cups-configuration} parameter} string server-admin
11844 Specifies the email address of the server administrator.
11846 Defaults to @samp{"root@@localhost.localdomain"}.
11849 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11850 The ServerAlias directive is used for HTTP Host header validation when
11851 clients connect to the scheduler from external interfaces. Using the
11852 special name @code{*} can expose your system to known browser-based DNS
11853 rebinding attacks, even when accessing sites through a firewall. If the
11854 auto-discovery of alternate names does not work, we recommend listing
11855 each alternate name with a ServerAlias directive instead of using
11858 Defaults to @samp{*}.
11861 @deftypevr {@code{cups-configuration} parameter} string server-name
11862 Specifies the fully-qualified host name of the server.
11864 Defaults to @samp{"localhost"}.
11867 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11868 Specifies what information is included in the Server header of HTTP
11869 responses. @code{None} disables the Server header. @code{ProductOnly}
11870 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11871 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11872 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11873 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11874 2.0.0 (@var{uname}) IPP/2.0}.
11876 Defaults to @samp{Minimal}.
11879 @deftypevr {@code{cups-configuration} parameter} string set-env
11880 Set the specified environment variable to be passed to child processes.
11882 Defaults to @samp{"variable value"}.
11885 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11886 Listens on the specified interfaces for encrypted connections. Valid
11887 values are of the form @var{address}:@var{port}, where @var{address} is
11888 either an IPv6 address enclosed in brackets, an IPv4 address, or
11889 @code{*} to indicate all addresses.
11891 Defaults to @samp{()}.
11894 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11895 Sets encryption options. By default, CUPS only supports encryption
11896 using TLS v1.0 or higher using known secure cipher suites. The
11897 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11898 required for some older clients that do not implement newer ones. The
11899 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11900 older clients that do not support TLS v1.0.
11902 Defaults to @samp{()}.
11905 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11906 Specifies whether the scheduler requires clients to strictly adhere to
11907 the IPP specifications.
11909 Defaults to @samp{#f}.
11912 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11913 Specifies the HTTP request timeout, in seconds.
11915 Defaults to @samp{300}.
11919 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11920 Specifies whether the web interface is enabled.
11922 Defaults to @samp{#f}.
11925 At this point you're probably thinking ``oh dear, Guix manual, I like
11926 you but you can stop already with the configuration options''. Indeed.
11927 However, one more point: it could be that you have an existing
11928 @code{cupsd.conf} that you want to use. In that case, you can pass an
11929 @code{opaque-cups-configuration} as the configuration of a
11930 @code{cups-service-type}.
11932 Available @code{opaque-cups-configuration} fields are:
11934 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11938 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11939 The contents of the @code{cupsd.conf}, as a string.
11942 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11943 The contents of the @code{cups-files.conf} file, as a string.
11946 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11947 strings of the same name, you could instantiate a CUPS service like
11951 (service cups-service-type
11952 (opaque-cups-configuration
11953 (cupsd.conf cupsd.conf)
11954 (cups-files.conf cups-files.conf)))
11958 @node Desktop Services
11959 @subsubsection Desktop Services
11961 The @code{(gnu services desktop)} module provides services that are
11962 usually useful in the context of a ``desktop'' setup---that is, on a
11963 machine running a graphical display server, possibly with graphical user
11964 interfaces, etc. It also defines services that provide specific desktop
11965 environments like GNOME and XFCE.
11967 To simplify things, the module defines a variable containing the set of
11968 services that users typically expect on a machine with a graphical
11969 environment and networking:
11971 @defvr {Scheme Variable} %desktop-services
11972 This is a list of services that builds upon @var{%base-services} and
11973 adds or adjusts services for a typical ``desktop'' setup.
11975 In particular, it adds a graphical login manager (@pxref{X Window,
11976 @code{slim-service}}), screen lockers, a network management tool
11977 (@pxref{Networking Services, @code{network-manager-service-type}}), energy and color
11978 management services, the @code{elogind} login and seat manager, the
11979 Polkit privilege service, the GeoClue location service, the
11980 AccountsService daemon that allows authorized users change system
11981 passwords, an NTP client (@pxref{Networking Services}), the Avahi
11982 daemon, and has the name service switch service configured to be able to
11983 use @code{nss-mdns} (@pxref{Name Service Switch, mDNS}).
11986 The @var{%desktop-services} variable can be used as the @code{services}
11987 field of an @code{operating-system} declaration (@pxref{operating-system
11988 Reference, @code{services}}).
11990 Additionally, the @code{gnome-desktop-service} and
11991 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11992 system. To ``add GNOME'' means that system-level services like the
11993 backlight adjustment helpers and the power management utilities are
11994 added to the system, extending @code{polkit} and @code{dbus}
11995 appropriately, allowing GNOME to operate with elevated privileges on a
11996 limited number of special-purpose system interfaces. Additionally,
11997 adding a service made by @code{gnome-desktop-service} adds the GNOME
11998 metapackage to the system profile. Likewise, adding the XFCE service
11999 not only adds the @code{xfce} metapackage to the system profile, but it
12000 also gives the Thunar file manager the ability to open a ``root-mode''
12001 file management window, if the user authenticates using the
12002 administrator's password via the standard polkit graphical interface.
12004 @deffn {Scheme Procedure} gnome-desktop-service
12005 Return a service that adds the @code{gnome} package to the system
12006 profile, and extends polkit with the actions from
12007 @code{gnome-settings-daemon}.
12010 @deffn {Scheme Procedure} xfce-desktop-service
12011 Return a service that adds the @code{xfce} package to the system profile,
12012 and extends polkit with the ability for @code{thunar} to manipulate the
12013 file system as root from within a user session, after the user has
12014 authenticated with the administrator's password.
12017 Because the GNOME and XFCE desktop services pull in so many packages,
12018 the default @code{%desktop-services} variable doesn't include either of
12019 them by default. To add GNOME or XFCE, just @code{cons} them onto
12020 @code{%desktop-services} in the @code{services} field of your
12021 @code{operating-system}:
12024 (use-modules (gnu))
12025 (use-service-modules desktop)
12028 ;; cons* adds items to the list given as its last argument.
12029 (services (cons* (gnome-desktop-service)
12030 (xfce-desktop-service)
12031 %desktop-services))
12035 These desktop environments will then be available as options in the
12036 graphical login window.
12038 The actual service definitions included in @code{%desktop-services} and
12039 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
12040 are described below.
12042 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
12043 Return a service that runs the ``system bus'', using @var{dbus}, with
12044 support for @var{services}.
12046 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
12047 facility. Its system bus is used to allow system services to communicate
12048 and to be notified of system-wide events.
12050 @var{services} must be a list of packages that provide an
12051 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
12052 and policy files. For example, to allow avahi-daemon to use the system bus,
12053 @var{services} must be equal to @code{(list avahi)}.
12056 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
12057 Return a service that runs the @code{elogind} login and
12058 seat management daemon. @uref{https://github.com/elogind/elogind,
12059 Elogind} exposes a D-Bus interface that can be used to know which users
12060 are logged in, know what kind of sessions they have open, suspend the
12061 system, inhibit system suspend, reboot the system, and other tasks.
12063 Elogind handles most system-level power events for a computer, for
12064 example suspending the system when a lid is closed, or shutting it down
12065 when the power button is pressed.
12067 The @var{config} keyword argument specifies the configuration for
12068 elogind, and should be the result of an @code{(elogind-configuration
12069 (@var{parameter} @var{value})...)} invocation. Available parameters and
12070 their default values are:
12073 @item kill-user-processes?
12075 @item kill-only-users
12077 @item kill-exclude-users
12079 @item inhibit-delay-max-seconds
12081 @item handle-power-key
12083 @item handle-suspend-key
12085 @item handle-hibernate-key
12087 @item handle-lid-switch
12089 @item handle-lid-switch-docked
12091 @item power-key-ignore-inhibited?
12093 @item suspend-key-ignore-inhibited?
12095 @item hibernate-key-ignore-inhibited?
12097 @item lid-switch-ignore-inhibited?
12099 @item holdoff-timeout-seconds
12103 @item idle-action-seconds
12105 @item runtime-directory-size-percent
12107 @item runtime-directory-size
12111 @item suspend-state
12112 @code{("mem" "standby" "freeze")}
12115 @item hibernate-state
12117 @item hibernate-mode
12118 @code{("platform" "shutdown")}
12119 @item hybrid-sleep-state
12121 @item hybrid-sleep-mode
12122 @code{("suspend" "platform" "shutdown")}
12126 @deffn {Scheme Procedure} accountsservice-service @
12127 [#:accountsservice @var{accountsservice}]
12128 Return a service that runs AccountsService, a system service that can
12129 list available accounts, change their passwords, and so on.
12130 AccountsService integrates with PolicyKit to enable unprivileged users
12131 to acquire the capability to modify their system configuration.
12132 @uref{https://www.freedesktop.org/wiki/Software/AccountsService/, the
12133 accountsservice web site} for more information.
12135 The @var{accountsservice} keyword argument is the @code{accountsservice}
12136 package to expose as a service.
12139 @deffn {Scheme Procedure} polkit-service @
12140 [#:polkit @var{polkit}]
12141 Return a service that runs the
12142 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
12143 management service}, which allows system administrators to grant access to
12144 privileged operations in a structured way. By querying the Polkit service, a
12145 privileged system component can know when it should grant additional
12146 capabilities to ordinary users. For example, an ordinary user can be granted
12147 the capability to suspend the system if the user is logged in locally.
12150 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
12151 [#:watts-up-pro? #f] @
12152 [#:poll-batteries? #t] @
12153 [#:ignore-lid? #f] @
12154 [#:use-percentage-for-policy? #f] @
12155 [#:percentage-low 10] @
12156 [#:percentage-critical 3] @
12157 [#:percentage-action 2] @
12158 [#:time-low 1200] @
12159 [#:time-critical 300] @
12160 [#:time-action 120] @
12161 [#:critical-power-action 'hybrid-sleep]
12162 Return a service that runs @uref{http://upower.freedesktop.org/,
12163 @command{upowerd}}, a system-wide monitor for power consumption and battery
12164 levels, with the given configuration settings. It implements the
12165 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
12169 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
12170 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
12171 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
12172 notifications and ways to mount/unmount disks. Programs that talk to UDisks
12173 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
12176 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
12177 Return a service that runs @command{colord}, a system service with a D-Bus
12178 interface to manage the color profiles of input and output devices such as
12179 screens and scanners. It is notably used by the GNOME Color Manager graphical
12180 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
12181 site} for more information.
12184 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
12185 Return a configuration allowing an application to access GeoClue
12186 location data. @var{name} is the Desktop ID of the application, without
12187 the @code{.desktop} part. If @var{allowed?} is true, the application
12188 will have access to location information by default. The boolean
12189 @var{system?} value indicates whether an application is a system component
12190 or not. Finally @var{users} is a list of UIDs of all users for which
12191 this application is allowed location info access. An empty users list
12192 means that all users are allowed.
12195 @defvr {Scheme Variable} %standard-geoclue-applications
12196 The standard list of well-known GeoClue application configurations,
12197 granting authority to the GNOME date-and-time utility to ask for the
12198 current location in order to set the time zone, and allowing the
12199 IceCat and Epiphany web browsers to request location information.
12200 IceCat and Epiphany both query the user before allowing a web page to
12201 know the user's location.
12204 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
12205 [#:whitelist '()] @
12206 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
12207 [#:submit-data? #f]
12208 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
12209 [#:submission-nick "geoclue"] @
12210 [#:applications %standard-geoclue-applications]
12211 Return a service that runs the GeoClue location service. This service
12212 provides a D-Bus interface to allow applications to request access to a
12213 user's physical location, and optionally to add information to online
12214 location databases. See
12215 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
12216 web site} for more information.
12219 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}] @
12220 [@w{#:auto-enable? #f}]
12221 Return a service that runs the @command{bluetoothd} daemon, which
12222 manages all the Bluetooth devices and provides a number of D-Bus
12223 interfaces. When AUTO-ENABLE? is true, the bluetooth controller is
12224 powered automatically at boot, which can be useful when using a
12225 bluetooth keyboard or mouse.
12227 Users need to be in the @code{lp} group to access the D-Bus service.
12230 @node Database Services
12231 @subsubsection Database Services
12235 The @code{(gnu services databases)} module provides the following services.
12237 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
12238 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
12239 [#:port 5432] [#:locale ``en_US.utf8'']
12240 Return a service that runs @var{postgresql}, the PostgreSQL database
12243 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
12244 creates a database cluster with @var{locale} as the default
12245 locale, stored in @var{data-directory}. It then listens on @var{port}.
12248 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
12249 Return a service that runs @command{mysqld}, the MySQL or MariaDB
12252 The optional @var{config} argument specifies the configuration for
12253 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
12256 @deftp {Data Type} mysql-configuration
12257 Data type representing the configuration of @var{mysql-service}.
12260 @item @code{mysql} (default: @var{mariadb})
12261 Package object of the MySQL database server, can be either @var{mariadb}
12264 For MySQL, a temporary root password will be displayed at activation time.
12265 For MariaDB, the root password is empty.
12267 @item @code{port} (default: @code{3306})
12268 TCP port on which the database server listens for incoming connections.
12272 @defvr {Scheme Variable} memcached-service-type
12273 This is the service type for the @uref{https://memcached.org/,
12274 Memcached} service, which provides a distributed in memory cache. The
12275 value for the service type is a @code{memcached-configuration} object.
12279 (service memcached-service-type)
12282 @deftp {Data Type} memcached-configuration
12283 Data type representing the configuration of memcached.
12286 @item @code{memcached} (default: @code{memcached})
12287 The Memcached package to use.
12289 @item @code{interfaces} (default: @code{'("0.0.0.0")})
12290 Network interfaces on which to listen.
12292 @item @code{tcp-port} (default: @code{11211})
12293 Port on which to accept connections on,
12295 @item @code{udp-port} (default: @code{11211})
12296 Port on which to accept UDP connections on, a value of 0 will disable
12297 listening on a UDP socket.
12299 @item @code{additional-options} (default: @code{'()})
12300 Additional command line options to pass to @code{memcached}.
12304 @defvr {Scheme Variable} mongodb-service-type
12305 This is the service type for @uref{https://www.mongodb.com/, MongoDB}.
12306 The value for the service type is a @code{mongodb-configuration} object.
12310 (service mongodb-service-type)
12313 @deftp {Data Type} mongodb-configuration
12314 Data type representing the configuration of mongodb.
12317 @item @code{mongodb} (default: @code{mongodb})
12318 The MongoDB package to use.
12320 @item @code{config-file} (default: @code{%default-mongodb-configuration-file})
12321 The configuration file for MongoDB.
12323 @item @code{data-directory} (default: @code{"/var/lib/mongodb"})
12324 This value is used to create the directory, so that it exists and is
12325 owned by the mongodb user. It should match the data-directory which
12326 MongoDB is configured to use through the configuration file.
12330 @defvr {Scheme Variable} redis-service-type
12331 This is the service type for the @uref{https://redis.io/, Redis}
12332 key/value store, whose value is a @code{redis-configuration} object.
12335 @deftp {Data Type} redis-configuration
12336 Data type representing the configuration of redis.
12339 @item @code{redis} (default: @code{redis})
12340 The Redis package to use.
12342 @item @code{bind} (default: @code{"127.0.0.1"})
12343 Network interface on which to listen.
12345 @item @code{port} (default: @code{6379})
12346 Port on which to accept connections on, a value of 0 will disable
12347 listening on a TCP socket.
12349 @item @code{working-directory} (default: @code{"/var/lib/redis"})
12350 Directory in which to store the database and related files.
12354 @node Mail Services
12355 @subsubsection Mail Services
12359 The @code{(gnu services mail)} module provides Guix service definitions
12360 for email services: IMAP, POP3, and LMTP servers, as well as mail
12361 transport agents (MTAs). Lots of acronyms! These services are detailed
12362 in the subsections below.
12364 @subsubheading Dovecot Service
12366 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
12367 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
12370 By default, Dovecot does not need much configuration; the default
12371 configuration object created by @code{(dovecot-configuration)} will
12372 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
12373 certificate will be generated for TLS-protected connections, though
12374 Dovecot will also listen on cleartext ports by default. There are a
12375 number of options, though, which mail administrators might need to change,
12376 and as is the case with other services, Guix allows the system
12377 administrator to specify these parameters via a uniform Scheme interface.
12379 For example, to specify that mail is located at @code{maildir~/.mail},
12380 one would instantiate the Dovecot service like this:
12383 (dovecot-service #:config
12384 (dovecot-configuration
12385 (mail-location "maildir:~/.mail")))
12388 The available configuration parameters follow. Each parameter
12389 definition is preceded by its type; for example, @samp{string-list foo}
12390 indicates that the @code{foo} parameter should be specified as a list of
12391 strings. There is also a way to specify the configuration as a string,
12392 if you have an old @code{dovecot.conf} file that you want to port over
12393 from some other system; see the end for more details.
12395 @c The following documentation was initially generated by
12396 @c (generate-documentation) in (gnu services mail). Manually maintained
12397 @c documentation is better, so we shouldn't hesitate to edit below as
12398 @c needed. However if the change you want to make to this documentation
12399 @c can be done in an automated way, it's probably easier to change
12400 @c (generate-documentation) than to make it below and have to deal with
12401 @c the churn as dovecot updates.
12403 Available @code{dovecot-configuration} fields are:
12405 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
12406 The dovecot package.
12409 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
12410 A list of IPs or hosts where to listen for connections. @samp{*}
12411 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
12412 interfaces. If you want to specify non-default ports or anything more
12413 complex, customize the address and port fields of the
12414 @samp{inet-listener} of the specific services you are interested in.
12417 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
12418 List of protocols we want to serve. Available protocols include
12419 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
12421 Available @code{protocol-configuration} fields are:
12423 @deftypevr {@code{protocol-configuration} parameter} string name
12424 The name of the protocol.
12427 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
12428 UNIX socket path to the master authentication server to find users.
12429 This is used by imap (for shared users) and lda.
12430 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12433 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
12434 Space separated list of plugins to load.
12437 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
12438 Maximum number of IMAP connections allowed for a user from each IP
12439 address. NOTE: The username is compared case-sensitively.
12440 Defaults to @samp{10}.
12445 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
12446 List of services to enable. Available services include @samp{imap},
12447 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
12450 Available @code{service-configuration} fields are:
12452 @deftypevr {@code{service-configuration} parameter} string kind
12453 The service kind. Valid values include @code{director},
12454 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
12455 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
12456 @code{tcpwrap}, @code{quota-warning}, or anything else.
12459 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
12460 Listeners for the service. A listener is either a
12461 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
12462 an @code{inet-listener-configuration}.
12463 Defaults to @samp{()}.
12465 Available @code{unix-listener-configuration} fields are:
12467 @deftypevr {@code{unix-listener-configuration} parameter} string path
12468 Path to the file, relative to @code{base-dir} field. This is also used as
12472 @deftypevr {@code{unix-listener-configuration} parameter} string mode
12473 The access mode for the socket.
12474 Defaults to @samp{"0600"}.
12477 @deftypevr {@code{unix-listener-configuration} parameter} string user
12478 The user to own the socket.
12479 Defaults to @samp{""}.
12482 @deftypevr {@code{unix-listener-configuration} parameter} string group
12483 The group to own the socket.
12484 Defaults to @samp{""}.
12488 Available @code{fifo-listener-configuration} fields are:
12490 @deftypevr {@code{fifo-listener-configuration} parameter} string path
12491 Path to the file, relative to @code{base-dir} field. This is also used as
12495 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
12496 The access mode for the socket.
12497 Defaults to @samp{"0600"}.
12500 @deftypevr {@code{fifo-listener-configuration} parameter} string user
12501 The user to own the socket.
12502 Defaults to @samp{""}.
12505 @deftypevr {@code{fifo-listener-configuration} parameter} string group
12506 The group to own the socket.
12507 Defaults to @samp{""}.
12511 Available @code{inet-listener-configuration} fields are:
12513 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
12514 The protocol to listen for.
12517 @deftypevr {@code{inet-listener-configuration} parameter} string address
12518 The address on which to listen, or empty for all addresses.
12519 Defaults to @samp{""}.
12522 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
12523 The port on which to listen.
12526 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
12527 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
12529 Defaults to @samp{#t}.
12534 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
12535 Number of connections to handle before starting a new process.
12536 Typically the only useful values are 0 (unlimited) or 1. 1 is more
12537 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
12538 Defaults to @samp{1}.
12541 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
12542 Number of processes to always keep waiting for more connections.
12543 Defaults to @samp{0}.
12546 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
12547 If you set @samp{service-count 0}, you probably need to grow
12549 Defaults to @samp{256000000}.
12554 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
12555 Dict configuration, as created by the @code{dict-configuration}
12558 Available @code{dict-configuration} fields are:
12560 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
12561 A list of key-value pairs that this dict should hold.
12562 Defaults to @samp{()}.
12567 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
12568 A list of passdb configurations, each one created by the
12569 @code{passdb-configuration} constructor.
12571 Available @code{passdb-configuration} fields are:
12573 @deftypevr {@code{passdb-configuration} parameter} string driver
12574 The driver that the passdb should use. Valid values include
12575 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
12577 Defaults to @samp{"pam"}.
12580 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
12581 Space separated list of arguments to the passdb driver.
12582 Defaults to @samp{""}.
12587 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
12588 List of userdb configurations, each one created by the
12589 @code{userdb-configuration} constructor.
12591 Available @code{userdb-configuration} fields are:
12593 @deftypevr {@code{userdb-configuration} parameter} string driver
12594 The driver that the userdb should use. Valid values include
12595 @samp{passwd} and @samp{static}.
12596 Defaults to @samp{"passwd"}.
12599 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
12600 Space separated list of arguments to the userdb driver.
12601 Defaults to @samp{""}.
12604 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
12605 Override fields from passwd.
12606 Defaults to @samp{()}.
12611 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
12612 Plug-in configuration, created by the @code{plugin-configuration}
12616 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
12617 List of namespaces. Each item in the list is created by the
12618 @code{namespace-configuration} constructor.
12620 Available @code{namespace-configuration} fields are:
12622 @deftypevr {@code{namespace-configuration} parameter} string name
12623 Name for this namespace.
12626 @deftypevr {@code{namespace-configuration} parameter} string type
12627 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
12628 Defaults to @samp{"private"}.
12631 @deftypevr {@code{namespace-configuration} parameter} string separator
12632 Hierarchy separator to use. You should use the same separator for
12633 all namespaces or some clients get confused. @samp{/} is usually a good
12634 one. The default however depends on the underlying mail storage
12636 Defaults to @samp{""}.
12639 @deftypevr {@code{namespace-configuration} parameter} string prefix
12640 Prefix required to access this namespace. This needs to be
12641 different for all namespaces. For example @samp{Public/}.
12642 Defaults to @samp{""}.
12645 @deftypevr {@code{namespace-configuration} parameter} string location
12646 Physical location of the mailbox. This is in the same format as
12647 mail_location, which is also the default for it.
12648 Defaults to @samp{""}.
12651 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
12652 There can be only one INBOX, and this setting defines which
12654 Defaults to @samp{#f}.
12657 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
12658 If namespace is hidden, it's not advertised to clients via NAMESPACE
12659 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
12660 useful when converting from another server with different namespaces
12661 which you want to deprecate but still keep working. For example you can
12662 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
12664 Defaults to @samp{#f}.
12667 @deftypevr {@code{namespace-configuration} parameter} boolean list?
12668 Show the mailboxes under this namespace with the LIST command. This
12669 makes the namespace visible for clients that do not support the NAMESPACE
12670 extension. The special @code{children} value lists child mailboxes, but
12671 hides the namespace prefix.
12672 Defaults to @samp{#t}.
12675 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
12676 Namespace handles its own subscriptions. If set to @code{#f}, the
12677 parent namespace handles them. The empty prefix should always have this
12679 Defaults to @samp{#t}.
12682 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
12683 List of predefined mailboxes in this namespace.
12684 Defaults to @samp{()}.
12686 Available @code{mailbox-configuration} fields are:
12688 @deftypevr {@code{mailbox-configuration} parameter} string name
12689 Name for this mailbox.
12692 @deftypevr {@code{mailbox-configuration} parameter} string auto
12693 @samp{create} will automatically create this mailbox.
12694 @samp{subscribe} will both create and subscribe to the mailbox.
12695 Defaults to @samp{"no"}.
12698 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
12699 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
12700 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
12701 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
12702 Defaults to @samp{()}.
12709 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
12710 Base directory where to store runtime data.
12711 Defaults to @samp{"/var/run/dovecot/"}.
12714 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
12715 Greeting message for clients.
12716 Defaults to @samp{"Dovecot ready."}.
12719 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
12720 List of trusted network ranges. Connections from these IPs are
12721 allowed to override their IP addresses and ports (for logging and for
12722 authentication checks). @samp{disable-plaintext-auth} is also ignored
12723 for these networks. Typically you would specify your IMAP proxy servers
12725 Defaults to @samp{()}.
12728 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
12729 List of login access check sockets (e.g. tcpwrap).
12730 Defaults to @samp{()}.
12733 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
12734 Show more verbose process titles (in ps). Currently shows user name
12735 and IP address. Useful for seeing who is actually using the IMAP
12736 processes (e.g. shared mailboxes or if the same uid is used for multiple
12738 Defaults to @samp{#f}.
12741 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
12742 Should all processes be killed when Dovecot master process shuts down.
12743 Setting this to @code{#f} means that Dovecot can be upgraded without
12744 forcing existing client connections to close (although that could also
12745 be a problem if the upgrade is e.g. due to a security fix).
12746 Defaults to @samp{#t}.
12749 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
12750 If non-zero, run mail commands via this many connections to doveadm
12751 server, instead of running them directly in the same process.
12752 Defaults to @samp{0}.
12755 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
12756 UNIX socket or host:port used for connecting to doveadm server.
12757 Defaults to @samp{"doveadm-server"}.
12760 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12761 List of environment variables that are preserved on Dovecot startup
12762 and passed down to all of its child processes. You can also give
12763 key=value pairs to always set specific settings.
12766 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12767 Disable LOGIN command and all other plaintext authentications unless
12768 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12769 matches the local IP (i.e. you're connecting from the same computer),
12770 the connection is considered secure and plaintext authentication is
12771 allowed. See also ssl=required setting.
12772 Defaults to @samp{#t}.
12775 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12776 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12777 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12778 for caching to be used.
12779 Defaults to @samp{0}.
12782 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12783 Time to live for cached data. After TTL expires the cached record
12784 is no longer used, *except* if the main database lookup returns internal
12785 failure. We also try to handle password changes automatically: If
12786 user's previous authentication was successful, but this one wasn't, the
12787 cache isn't used. For now this works only with plaintext
12789 Defaults to @samp{"1 hour"}.
12792 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12793 TTL for negative hits (user not found, password mismatch).
12794 0 disables caching them completely.
12795 Defaults to @samp{"1 hour"}.
12798 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12799 List of realms for SASL authentication mechanisms that need them.
12800 You can leave it empty if you don't want to support multiple realms.
12801 Many clients simply use the first one listed here, so keep the default
12803 Defaults to @samp{()}.
12806 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12807 Default realm/domain to use if none was specified. This is used for
12808 both SASL realms and appending @@domain to username in plaintext
12810 Defaults to @samp{""}.
12813 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12814 List of allowed characters in username. If the user-given username
12815 contains a character not listed in here, the login automatically fails.
12816 This is just an extra check to make sure user can't exploit any
12817 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12818 you want to allow all characters, set this value to empty.
12819 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12822 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12823 Username character translations before it's looked up from
12824 databases. The value contains series of from -> to characters. For
12825 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12826 translated to @samp{@@}.
12827 Defaults to @samp{""}.
12830 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12831 Username formatting before it's looked up from databases. You can
12832 use the standard variables here, e.g. %Lu would lowercase the username,
12833 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12834 change the @samp{@@} into @samp{-AT-}. This translation is done after
12835 @samp{auth-username-translation} changes.
12836 Defaults to @samp{"%Lu"}.
12839 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12840 If you want to allow master users to log in by specifying the master
12841 username within the normal username string (i.e. not using SASL
12842 mechanism's support for it), you can specify the separator character
12843 here. The format is then <username><separator><master username>.
12844 UW-IMAP uses @samp{*} as the separator, so that could be a good
12846 Defaults to @samp{""}.
12849 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12850 Username to use for users logging in with ANONYMOUS SASL
12852 Defaults to @samp{"anonymous"}.
12855 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12856 Maximum number of dovecot-auth worker processes. They're used to
12857 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12858 They're automatically created and destroyed as needed.
12859 Defaults to @samp{30}.
12862 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12863 Host name to use in GSSAPI principal names. The default is to use
12864 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12865 allow all keytab entries.
12866 Defaults to @samp{""}.
12869 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12870 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12871 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12872 need to change the auth service to run as root to be able to read this
12874 Defaults to @samp{""}.
12877 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12878 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12879 and @samp{ntlm-auth} helper.
12880 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12881 Defaults to @samp{#f}.
12884 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12885 Path for Samba's @samp{ntlm-auth} helper binary.
12886 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12889 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12890 Time to delay before replying to failed authentications.
12891 Defaults to @samp{"2 secs"}.
12894 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12895 Require a valid SSL client certificate or the authentication
12897 Defaults to @samp{#f}.
12900 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12901 Take the username from client's SSL certificate, using
12902 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12904 Defaults to @samp{#f}.
12907 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12908 List of wanted authentication mechanisms. Supported mechanisms are:
12909 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12910 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12911 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12912 @samp{disable-plaintext-auth} setting.
12915 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12916 List of IPs or hostnames to all director servers, including ourself.
12917 Ports can be specified as ip:port. The default port is the same as what
12918 director service's @samp{inet-listener} is using.
12919 Defaults to @samp{()}.
12922 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12923 List of IPs or hostnames to all backend mail servers. Ranges are
12924 allowed too, like 10.0.0.10-10.0.0.30.
12925 Defaults to @samp{()}.
12928 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12929 How long to redirect users to a specific server after it no longer
12930 has any connections.
12931 Defaults to @samp{"15 min"}.
12934 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12935 TCP/IP port that accepts doveadm connections (instead of director
12936 connections) If you enable this, you'll also need to add
12937 @samp{inet-listener} for the port.
12938 Defaults to @samp{0}.
12941 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12942 How the username is translated before being hashed. Useful values
12943 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12944 are shared within domain.
12945 Defaults to @samp{"%Lu"}.
12948 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12949 Log file to use for error messages. @samp{syslog} logs to syslog,
12950 @samp{/dev/stderr} logs to stderr.
12951 Defaults to @samp{"syslog"}.
12954 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12955 Log file to use for informational messages. Defaults to
12957 Defaults to @samp{""}.
12960 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12961 Log file to use for debug messages. Defaults to
12962 @samp{info-log-path}.
12963 Defaults to @samp{""}.
12966 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12967 Syslog facility to use if you're logging to syslog. Usually if you
12968 don't want to use @samp{mail}, you'll use local0..local7. Also other
12969 standard facilities are supported.
12970 Defaults to @samp{"mail"}.
12973 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12974 Log unsuccessful authentication attempts and the reasons why they
12976 Defaults to @samp{#f}.
12979 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12980 In case of password mismatches, log the attempted password. Valid
12981 values are no, plain and sha1. sha1 can be useful for detecting brute
12982 force password attempts vs. user simply trying the same password over
12983 and over again. You can also truncate the value to n chars by appending
12984 ":n" (e.g. sha1:6).
12985 Defaults to @samp{#f}.
12988 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12989 Even more verbose logging for debugging purposes. Shows for example
12991 Defaults to @samp{#f}.
12994 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12995 In case of password mismatches, log the passwords and used scheme so
12996 the problem can be debugged. Enabling this also enables
12998 Defaults to @samp{#f}.
13001 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
13002 Enable mail process debugging. This can help you figure out why
13003 Dovecot isn't finding your mails.
13004 Defaults to @samp{#f}.
13007 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
13008 Show protocol level SSL errors.
13009 Defaults to @samp{#f}.
13012 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
13013 Prefix for each line written to log file. % codes are in
13014 strftime(3) format.
13015 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
13018 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
13019 List of elements we want to log. The elements which have a
13020 non-empty variable value are joined together to form a comma-separated
13024 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
13025 Login log format. %s contains @samp{login-log-format-elements}
13026 string, %$ contains the data we want to log.
13027 Defaults to @samp{"%$: %s"}.
13030 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
13031 Log prefix for mail processes. See doc/wiki/Variables.txt for list
13032 of possible variables you can use.
13033 Defaults to @samp{"\"%s(%u): \""}.
13036 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
13037 Format to use for logging mail deliveries. You can use variables:
13040 Delivery status message (e.g. @samp{saved to INBOX})
13052 Defaults to @samp{"msgid=%m: %$"}.
13055 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
13056 Location for users' mailboxes. The default is empty, which means
13057 that Dovecot tries to find the mailboxes automatically. This won't work
13058 if the user doesn't yet have any mail, so you should explicitly tell
13059 Dovecot the full location.
13061 If you're using mbox, giving a path to the INBOX
13062 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
13063 where the other mailboxes are kept. This is called the "root mail
13064 directory", and it must be the first path given in the
13065 @samp{mail-location} setting.
13067 There are a few special variables you can use, eg.:
13073 user part in user@@domain, same as %u if there's no domain
13075 domain part in user@@domain, empty if there's no domain
13080 See doc/wiki/Variables.txt for full list. Some examples:
13082 @item maildir:~/Maildir
13083 @item mbox:~/mail:INBOX=/var/mail/%u
13084 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
13086 Defaults to @samp{""}.
13089 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
13090 System user and group used to access mails. If you use multiple,
13091 userdb can override these by returning uid or gid fields. You can use
13092 either numbers or names. <doc/wiki/UserIds.txt>.
13093 Defaults to @samp{""}.
13096 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
13098 Defaults to @samp{""}.
13101 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
13102 Group to enable temporarily for privileged operations. Currently
13103 this is used only with INBOX when either its initial creation or
13104 dotlocking fails. Typically this is set to "mail" to give access to
13106 Defaults to @samp{""}.
13109 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
13110 Grant access to these supplementary groups for mail processes.
13111 Typically these are used to set up access to shared mailboxes. Note
13112 that it may be dangerous to set these if users can create
13113 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
13114 could allow a user to delete others' mailboxes, or ln -s
13115 /secret/shared/box ~/mail/mybox would allow reading it).
13116 Defaults to @samp{""}.
13119 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
13120 Allow full file system access to clients. There's no access checks
13121 other than what the operating system does for the active UID/GID. It
13122 works with both maildir and mboxes, allowing you to prefix mailboxes
13123 names with e.g. /path/ or ~user/.
13124 Defaults to @samp{#f}.
13127 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
13128 Don't use mmap() at all. This is required if you store indexes to
13129 shared file systems (NFS or clustered file system).
13130 Defaults to @samp{#f}.
13133 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
13134 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
13135 supports @samp{O_EXCL} since version 3, so this should be safe to use
13136 nowadays by default.
13137 Defaults to @samp{#t}.
13140 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
13141 When to use fsync() or fdatasync() calls:
13144 Whenever necessary to avoid losing important data
13146 Useful with e.g. NFS when write()s are delayed
13148 Never use it (best performance, but crashes can lose data).
13150 Defaults to @samp{"optimized"}.
13153 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
13154 Mail storage exists in NFS. Set this to yes to make Dovecot flush
13155 NFS caches whenever needed. If you're using only a single mail server
13157 Defaults to @samp{#f}.
13160 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
13161 Mail index files also exist in NFS. Setting this to yes requires
13162 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
13163 Defaults to @samp{#f}.
13166 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
13167 Locking method for index files. Alternatives are fcntl, flock and
13168 dotlock. Dotlocking uses some tricks which may create more disk I/O
13169 than other locking methods. NFS users: flock doesn't work, remember to
13170 change @samp{mmap-disable}.
13171 Defaults to @samp{"fcntl"}.
13174 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
13175 Directory in which LDA/LMTP temporarily stores incoming mails >128
13177 Defaults to @samp{"/tmp"}.
13180 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
13181 Valid UID range for users. This is mostly to make sure that users can't
13182 log in as daemons or other system users. Note that denying root logins is
13183 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
13185 Defaults to @samp{500}.
13188 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
13190 Defaults to @samp{0}.
13193 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
13194 Valid GID range for users. Users having non-valid GID as primary group ID
13195 aren't allowed to log in. If user belongs to supplementary groups with
13196 non-valid GIDs, those groups are not set.
13197 Defaults to @samp{1}.
13200 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
13202 Defaults to @samp{0}.
13205 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
13206 Maximum allowed length for mail keyword name. It's only forced when
13207 trying to create new keywords.
13208 Defaults to @samp{50}.
13211 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
13212 List of directories under which chrooting is allowed for mail
13213 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
13214 too). This setting doesn't affect @samp{login-chroot}
13215 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
13216 "/./" in home dirs are ignored. WARNING: Never add directories here
13217 which local users can modify, that may lead to root exploit. Usually
13218 this should be done only if you don't allow shell access for users.
13219 <doc/wiki/Chrooting.txt>.
13220 Defaults to @samp{()}.
13223 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
13224 Default chroot directory for mail processes. This can be overridden
13225 for specific users in user database by giving /./ in user's home
13226 directory (e.g. /home/./user chroots into /home). Note that usually
13227 there is no real need to do chrooting, Dovecot doesn't allow users to
13228 access files outside their mail directory anyway. If your home
13229 directories are prefixed with the chroot directory, append "/." to
13230 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
13231 Defaults to @samp{""}.
13234 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
13235 UNIX socket path to master authentication server to find users.
13236 This is used by imap (for shared users) and lda.
13237 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
13240 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
13241 Directory where to look up mail plugins.
13242 Defaults to @samp{"/usr/lib/dovecot"}.
13245 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
13246 List of plugins to load for all services. Plugins specific to IMAP,
13247 LDA, etc. are added to this list in their own .conf files.
13248 Defaults to @samp{()}.
13251 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
13252 The minimum number of mails in a mailbox before updates are done to
13253 cache file. This allows optimizing Dovecot's behavior to do less disk
13254 writes at the cost of more disk reads.
13255 Defaults to @samp{0}.
13258 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
13259 When IDLE command is running, mailbox is checked once in a while to
13260 see if there are any new mails or other changes. This setting defines
13261 the minimum time to wait between those checks. Dovecot can also use
13262 dnotify, inotify and kqueue to find out immediately when changes
13264 Defaults to @samp{"30 secs"}.
13267 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
13268 Save mails with CR+LF instead of plain LF. This makes sending those
13269 mails take less CPU, especially with sendfile() syscall with Linux and
13270 FreeBSD. But it also creates a bit more disk I/O which may just make it
13271 slower. Also note that if other software reads the mboxes/maildirs,
13272 they may handle the extra CRs wrong and cause problems.
13273 Defaults to @samp{#f}.
13276 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
13277 By default LIST command returns all entries in maildir beginning
13278 with a dot. Enabling this option makes Dovecot return only entries
13279 which are directories. This is done by stat()ing each entry, so it
13280 causes more disk I/O.
13281 (For systems setting struct @samp{dirent->d_type} this check is free
13282 and it's done always regardless of this setting).
13283 Defaults to @samp{#f}.
13286 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
13287 When copying a message, do it with hard links whenever possible.
13288 This makes the performance much better, and it's unlikely to have any
13290 Defaults to @samp{#t}.
13293 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
13294 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
13295 directory only when its mtime changes unexpectedly or when we can't find
13296 the mail otherwise.
13297 Defaults to @samp{#f}.
13300 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
13301 Which locking methods to use for locking mbox. There are four
13306 Create <mailbox>.lock file. This is the oldest and most NFS-safe
13307 solution. If you want to use /var/mail/ like directory, the users will
13308 need write access to that directory.
13310 Same as dotlock, but if it fails because of permissions or because there
13311 isn't enough disk space, just skip it.
13313 Use this if possible. Works with NFS too if lockd is used.
13315 May not exist in all systems. Doesn't work with NFS.
13317 May not exist in all systems. Doesn't work with NFS.
13320 You can use multiple locking methods; if you do the order they're declared
13321 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
13322 locking methods as well. Some operating systems don't allow using some of
13323 them simultaneously.
13326 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
13330 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
13331 Maximum time to wait for lock (all of them) before aborting.
13332 Defaults to @samp{"5 mins"}.
13335 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
13336 If dotlock exists but the mailbox isn't modified in any way,
13337 override the lock file after this much time.
13338 Defaults to @samp{"2 mins"}.
13341 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
13342 When mbox changes unexpectedly we have to fully read it to find out
13343 what changed. If the mbox is large this can take a long time. Since
13344 the change is usually just a newly appended mail, it'd be faster to
13345 simply read the new mails. If this setting is enabled, Dovecot does
13346 this but still safely fallbacks to re-reading the whole mbox file
13347 whenever something in mbox isn't how it's expected to be. The only real
13348 downside to this setting is that if some other MUA changes message
13349 flags, Dovecot doesn't notice it immediately. Note that a full sync is
13350 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
13351 Defaults to @samp{#t}.
13354 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
13355 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
13356 EXAMINE, EXPUNGE or CHECK commands. If this is set,
13357 @samp{mbox-dirty-syncs} is ignored.
13358 Defaults to @samp{#f}.
13361 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
13362 Delay writing mbox headers until doing a full write sync (EXPUNGE
13363 and CHECK commands and when closing the mailbox). This is especially
13364 useful for POP3 where clients often delete all mails. The downside is
13365 that our changes aren't immediately visible to other MUAs.
13366 Defaults to @samp{#t}.
13369 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
13370 If mbox size is smaller than this (e.g. 100k), don't write index
13371 files. If an index file already exists it's still read, just not
13373 Defaults to @samp{0}.
13376 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
13377 Maximum dbox file size until it's rotated.
13378 Defaults to @samp{2000000}.
13381 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
13382 Maximum dbox file age until it's rotated. Typically in days. Day
13383 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
13385 Defaults to @samp{"1d"}.
13388 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
13389 When creating new mdbox files, immediately preallocate their size to
13390 @samp{mdbox-rotate-size}. This setting currently works only in Linux
13391 with some file systems (ext4, xfs).
13392 Defaults to @samp{#f}.
13395 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
13396 sdbox and mdbox support saving mail attachments to external files,
13397 which also allows single instance storage for them. Other backends
13398 don't support this for now.
13400 WARNING: This feature hasn't been tested much yet. Use at your own risk.
13402 Directory root where to store mail attachments. Disabled, if empty.
13403 Defaults to @samp{""}.
13406 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
13407 Attachments smaller than this aren't saved externally. It's also
13408 possible to write a plugin to disable saving specific attachments
13410 Defaults to @samp{128000}.
13413 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
13414 File system backend to use for saving attachments:
13417 No SiS done by Dovecot (but this might help FS's own deduplication)
13419 SiS with immediate byte-by-byte comparison during saving
13420 @item sis-queue posix
13421 SiS with delayed comparison and deduplication.
13423 Defaults to @samp{"sis posix"}.
13426 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
13427 Hash format to use in attachment filenames. You can add any text and
13428 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
13429 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
13430 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
13431 Defaults to @samp{"%@{sha1@}"}.
13434 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
13436 Defaults to @samp{100}.
13439 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
13441 Defaults to @samp{1000}.
13444 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
13445 Default VSZ (virtual memory size) limit for service processes.
13446 This is mainly intended to catch and kill processes that leak memory
13447 before they eat up everything.
13448 Defaults to @samp{256000000}.
13451 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
13452 Login user is internally used by login processes. This is the most
13453 untrusted user in Dovecot system. It shouldn't have access to anything
13455 Defaults to @samp{"dovenull"}.
13458 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
13459 Internal user is used by unprivileged processes. It should be
13460 separate from login user, so that login processes can't disturb other
13462 Defaults to @samp{"dovecot"}.
13465 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
13466 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
13467 Defaults to @samp{"required"}.
13470 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
13471 PEM encoded X.509 SSL/TLS certificate (public key).
13472 Defaults to @samp{"</etc/dovecot/default.pem"}.
13475 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
13476 PEM encoded SSL/TLS private key. The key is opened before
13477 dropping root privileges, so keep the key file unreadable by anyone but
13479 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
13482 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
13483 If key file is password protected, give the password here.
13484 Alternatively give it when starting dovecot with -p parameter. Since
13485 this file is often world-readable, you may want to place this setting
13486 instead to a different.
13487 Defaults to @samp{""}.
13490 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
13491 PEM encoded trusted certificate authority. Set this only if you
13492 intend to use @samp{ssl-verify-client-cert? #t}. The file should
13493 contain the CA certificate(s) followed by the matching
13494 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
13495 Defaults to @samp{""}.
13498 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
13499 Require that CRL check succeeds for client certificates.
13500 Defaults to @samp{#t}.
13503 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
13504 Request client to send a certificate. If you also want to require
13505 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
13506 Defaults to @samp{#f}.
13509 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
13510 Which field from certificate to use for username. commonName and
13511 x500UniqueIdentifier are the usual choices. You'll also need to set
13512 @samp{auth-ssl-username-from-cert? #t}.
13513 Defaults to @samp{"commonName"}.
13516 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
13517 How often to regenerate the SSL parameters file. Generation is
13518 quite CPU intensive operation. The value is in hours, 0 disables
13519 regeneration entirely.
13520 Defaults to @samp{168}.
13523 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
13524 SSL protocols to use.
13525 Defaults to @samp{"!SSLv2"}.
13528 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
13529 SSL ciphers to use.
13530 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
13533 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
13534 SSL crypto device to use, for valid values run "openssl engine".
13535 Defaults to @samp{""}.
13538 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
13539 Address to use when sending rejection mails.
13540 %d expands to recipient domain.
13541 Defaults to @samp{"postmaster@@%d"}.
13544 @deftypevr {@code{dovecot-configuration} parameter} string hostname
13545 Hostname to use in various parts of sent mails (e.g. in Message-Id)
13546 and in LMTP replies. Default is the system's real hostname@@domain.
13547 Defaults to @samp{""}.
13550 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
13551 If user is over quota, return with temporary failure instead of
13553 Defaults to @samp{#f}.
13556 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
13557 Binary to use for sending mails.
13558 Defaults to @samp{"/usr/sbin/sendmail"}.
13561 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
13562 If non-empty, send mails via this SMTP host[:port] instead of
13564 Defaults to @samp{""}.
13567 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
13568 Subject: header to use for rejection mails. You can use the same
13569 variables as for @samp{rejection-reason} below.
13570 Defaults to @samp{"Rejected: %s"}.
13573 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
13574 Human readable error message for rejection mails. You can use
13587 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
13590 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
13591 Delimiter character between local-part and detail in email
13593 Defaults to @samp{"+"}.
13596 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
13597 Header where the original recipient address (SMTP's RCPT TO:
13598 address) is taken from if not available elsewhere. With dovecot-lda -a
13599 parameter overrides this. A commonly used header for this is
13601 Defaults to @samp{""}.
13604 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
13605 Should saving a mail to a nonexistent mailbox automatically create
13607 Defaults to @samp{#f}.
13610 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
13611 Should automatically created mailboxes be also automatically
13613 Defaults to @samp{#f}.
13616 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
13617 Maximum IMAP command line length. Some clients generate very long
13618 command lines with huge mailboxes, so you may need to raise this if you
13619 get "Too long argument" or "IMAP command line too large" errors
13621 Defaults to @samp{64000}.
13624 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
13625 IMAP logout format string:
13628 total number of bytes read from client
13630 total number of bytes sent to client.
13632 Defaults to @samp{"in=%i out=%o"}.
13635 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
13636 Override the IMAP CAPABILITY response. If the value begins with '+',
13637 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
13638 Defaults to @samp{""}.
13641 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
13642 How long to wait between "OK Still here" notifications when client
13644 Defaults to @samp{"2 mins"}.
13647 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
13648 ID field names and values to send to clients. Using * as the value
13649 makes Dovecot use the default value. The following fields have default
13650 values currently: name, version, os, os-version, support-url,
13652 Defaults to @samp{""}.
13655 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
13656 ID fields sent by client to log. * means everything.
13657 Defaults to @samp{""}.
13660 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
13661 Workarounds for various client bugs:
13664 @item delay-newmail
13665 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
13666 CHECK commands. Some clients ignore them otherwise, for example OSX
13667 Mail (<v2.1). Outlook Express breaks more badly though, without this it
13668 may show user "Message no longer in server" errors. Note that OE6
13669 still breaks even with this workaround if synchronization is set to
13672 @item tb-extra-mailbox-sep
13673 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
13674 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
13675 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
13677 @item tb-lsub-flags
13678 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
13679 This makes Thunderbird realize they aren't selectable and show them
13680 greyed out, instead of only later giving "not selectable" popup error.
13682 Defaults to @samp{()}.
13685 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
13686 Host allowed in URLAUTH URLs sent by client. "*" allows all.
13687 Defaults to @samp{""}.
13691 Whew! Lots of configuration options. The nice thing about it though is
13692 that GuixSD has a complete interface to Dovecot's configuration
13693 language. This allows not only a nice way to declare configurations,
13694 but also offers reflective capabilities as well: users can write code to
13695 inspect and transform configurations from within Scheme.
13697 However, it could be that you just want to get a @code{dovecot.conf} up
13698 and running. In that case, you can pass an
13699 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
13700 @code{dovecot-service}. As its name indicates, an opaque configuration
13701 does not have easy reflective capabilities.
13703 Available @code{opaque-dovecot-configuration} fields are:
13705 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
13706 The dovecot package.
13709 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
13710 The contents of the @code{dovecot.conf}, as a string.
13713 For example, if your @code{dovecot.conf} is just the empty string, you
13714 could instantiate a dovecot service like this:
13717 (dovecot-service #:config
13718 (opaque-dovecot-configuration
13722 @subsubheading OpenSMTPD Service
13724 @deffn {Scheme Variable} opensmtpd-service-type
13725 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
13726 service, whose value should be an @code{opensmtpd-configuration} object
13727 as in this example:
13730 (service opensmtpd-service-type
13731 (opensmtpd-configuration
13732 (config-file (local-file "./my-smtpd.conf"))))
13736 @deftp {Data Type} opensmtpd-configuration
13737 Data type representing the configuration of opensmtpd.
13740 @item @code{package} (default: @var{opensmtpd})
13741 Package object of the OpenSMTPD SMTP server.
13743 @item @code{config-file} (default: @var{%default-opensmtpd-file})
13744 File-like object of the OpenSMTPD configuration file to use. By default
13745 it listens on the loopback network interface, and allows for mail from
13746 users and daemons on the local machine, as well as permitting email to
13747 remote servers. Run @command{man smtpd.conf} for more information.
13752 @subsubheading Exim Service
13754 @cindex mail transfer agent (MTA)
13755 @cindex MTA (mail transfer agent)
13758 @deffn {Scheme Variable} exim-service-type
13759 This is the type of the @uref{https://exim.org, Exim} mail transfer
13760 agent (MTA), whose value should be an @code{exim-configuration} object
13761 as in this example:
13764 (service exim-service-type
13765 (exim-configuration
13766 (config-file (local-file "./my-exim.conf"))))
13770 In order to use an @code{exim-service-type} service you must also have a
13771 @code{mail-aliases-service-type} service present in your
13772 @code{operating-system} (even if it has no aliases).
13774 @deftp {Data Type} exim-configuration
13775 Data type representing the configuration of exim.
13778 @item @code{package} (default: @var{exim})
13779 Package object of the Exim server.
13781 @item @code{config-file} (default: @code{#f})
13782 File-like object of the Exim configuration file to use. If its value is
13783 @code{#f} then use the default configuration file from the package
13784 provided in @code{package}. The resulting configuration file is loaded
13785 after setting the @code{exim_user} and @code{exim_group} configuration
13791 @subsubheading Mail Aliases Service
13793 @cindex email aliases
13794 @cindex aliases, for email addresses
13796 @deffn {Scheme Variable} mail-aliases-service-type
13797 This is the type of the service which provides @code{/etc/aliases},
13798 specifying how to deliver mail to users on this system.
13801 (service mail-aliases-service-type
13802 '(("postmaster" "bob")
13803 ("bob" "bob@@example.com" "bob@@example2.com")))
13807 The configuration for a @code{mail-aliases-service-type} service is an
13808 association list denoting how to deliver mail that comes to this
13809 system. Each entry is of the form @code{(alias addresses ...)}, with
13810 @code{alias} specifying the local alias and @code{addresses} specifying
13811 where to deliver this user's mail.
13813 The aliases aren't required to exist as users on the local system. In
13814 the above example, there doesn't need to be a @code{postmaster} entry in
13815 the @code{operating-system}'s @code{user-accounts} in order to deliver
13816 the @code{postmaster} mail to @code{bob} (which subsequently would
13817 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13819 @node Messaging Services
13820 @subsubsection Messaging Services
13825 The @code{(gnu services messaging)} module provides Guix service
13826 definitions for messaging services: currently only Prosody is supported.
13828 @subsubheading Prosody Service
13830 @deffn {Scheme Variable} prosody-service-type
13831 This is the type for the @uref{http://prosody.im, Prosody XMPP
13832 communication server}. Its value must be a @code{prosody-configuration}
13833 record as in this example:
13836 (service prosody-service-type
13837 (prosody-configuration
13838 (modules-enabled (cons "groups" %default-modules-enabled))
13841 (int-component-configuration
13842 (hostname "conference.example.net")
13844 (mod-muc (mod-muc-configuration)))))
13847 (virtualhost-configuration
13848 (domain "example.net"))))))
13851 See below for details about @code{prosody-configuration}.
13855 By default, Prosody does not need much configuration. Only one
13856 @code{virtualhosts} field is needed: it specifies the domain you wish
13859 Prosodyctl will help you generate X.509 certificates and keys:
13862 prosodyctl cert request example.net
13865 The available configuration parameters follow. Each parameter
13866 definition is preceded by its type; for example, @samp{string-list foo}
13867 indicates that the @code{foo} parameter should be specified as a list of
13868 strings. Types starting with @code{maybe-} denote parameters that won't
13869 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13871 There is also a way to specify the configuration as a string, if you
13872 have an old @code{prosody.cfg.lua} file that you want to port over from
13873 some other system; see the end for more details.
13875 @c The following documentation was initially generated by
13876 @c (generate-documentation) in (gnu services messaging). Manually maintained
13877 @c documentation is better, so we shouldn't hesitate to edit below as
13878 @c needed. However if the change you want to make to this documentation
13879 @c can be done in an automated way, it's probably easier to change
13880 @c (generate-documentation) than to make it below and have to deal with
13881 @c the churn as Prosody updates.
13883 Available @code{prosody-configuration} fields are:
13885 @deftypevr {@code{prosody-configuration} parameter} package prosody
13886 The Prosody package.
13889 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13890 Location of the Prosody data storage directory. See
13891 @url{http://prosody.im/doc/configure}.
13892 Defaults to @samp{"/var/lib/prosody"}.
13895 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13896 Additional plugin directories. They are searched in all the specified
13897 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13898 Defaults to @samp{()}.
13901 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13902 This is a list of accounts that are admins for the server. Note that you
13903 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13904 @url{http://prosody.im/doc/creating_accounts}.
13905 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13906 Defaults to @samp{()}.
13909 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13910 Enable use of libevent for better performance under high load. See
13911 @url{http://prosody.im/doc/libevent}.
13912 Defaults to @samp{#f}.
13915 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13916 This is the list of modules Prosody will load on startup. It looks for
13917 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13918 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13919 Defaults to @samp{%default-modules-enabled}.
13922 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13923 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13924 should you want to disable them then add them to this list.
13925 Defaults to @samp{()}.
13928 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13929 Path to a text file where the shared groups are defined. If this path is
13930 empty then @samp{mod_groups} does nothing. See
13931 @url{http://prosody.im/doc/modules/mod_groups}.
13932 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13935 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13936 Disable account creation by default, for security. See
13937 @url{http://prosody.im/doc/creating_accounts}.
13938 Defaults to @samp{#f}.
13941 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13942 These are the SSL/TLS-related settings. Most of them are disabled so to
13943 use Prosody's defaults. If you do not completely understand these options, do
13944 not add them to your config, it is easy to lower the security of your server
13945 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13947 Available @code{ssl-configuration} fields are:
13949 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13950 This determines what handshake to use.
13953 @deftypevr {@code{ssl-configuration} parameter} file-name key
13954 Path to your private key file, relative to @code{/etc/prosody}.
13955 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13958 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13959 Path to your certificate file, relative to @code{/etc/prosody}.
13960 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13963 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13964 Path to directory containing root certificates that you wish Prosody to
13965 trust when verifying the certificates of remote servers.
13966 Defaults to @samp{"/etc/ssl/certs"}.
13969 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13970 Path to a file containing root certificates that you wish Prosody to trust.
13971 Similar to @code{capath} but with all certificates concatenated together.
13974 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13975 A list of verification options (these mostly map to OpenSSL's
13976 @code{set_verify()} flags).
13979 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13980 A list of general options relating to SSL/TLS. These map to OpenSSL's
13981 @code{set_options()}. For a full list of options available in LuaSec, see the
13985 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13986 How long a chain of certificate authorities to check when looking for a
13987 trusted root certificate.
13990 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13991 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13992 clients, and in what order.
13995 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13996 A path to a file containing parameters for Diffie-Hellman key exchange. You
13997 can create such a file with:
13998 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
14001 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
14002 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
14003 @samp{"secp384r1"}.
14006 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
14007 A list of "extra" verification options.
14010 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
14011 Password for encrypted private keys.
14016 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
14017 Whether to force all client-to-server connections to be encrypted or not.
14018 See @url{http://prosody.im/doc/modules/mod_tls}.
14019 Defaults to @samp{#f}.
14022 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
14023 Whether to force all server-to-server connections to be encrypted or not.
14024 See @url{http://prosody.im/doc/modules/mod_tls}.
14025 Defaults to @samp{#f}.
14028 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
14029 Whether to require encryption and certificate authentication. This
14030 provides ideal security, but requires servers you communicate with to support
14031 encryption AND present valid, trusted certificates. See
14032 @url{http://prosody.im/doc/s2s#security}.
14033 Defaults to @samp{#f}.
14036 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
14037 Many servers don't support encryption or have invalid or self-signed
14038 certificates. You can list domains here that will not be required to
14039 authenticate using certificates. They will be authenticated using DNS. See
14040 @url{http://prosody.im/doc/s2s#security}.
14041 Defaults to @samp{()}.
14044 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
14045 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
14046 valid certificates for some domains by specifying a list here. See
14047 @url{http://prosody.im/doc/s2s#security}.
14048 Defaults to @samp{()}.
14051 @deftypevr {@code{prosody-configuration} parameter} string authentication
14052 Select the authentication backend to use. The default provider stores
14053 passwords in plaintext and uses Prosody's configured data storage to store the
14054 authentication data. If you do not trust your server please see
14055 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
14056 about using the hashed backend. See also
14057 @url{http://prosody.im/doc/authentication}
14058 Defaults to @samp{"internal_plain"}.
14061 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
14062 Set logging options. Advanced logging configuration is not yet supported
14063 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
14064 Defaults to @samp{"*syslog"}.
14067 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
14068 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
14069 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
14072 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
14073 A host in Prosody is a domain on which user accounts can be created. For
14074 example if you want your users to have addresses like
14075 @samp{"john.smith@@example.com"} then you need to add a host
14076 @samp{"example.com"}. All options in this list will apply only to this host.
14078 Note: the name "virtual" host is used in configuration to avoid confusion with
14079 the actual physical host that Prosody is installed on. A single Prosody
14080 instance can serve many domains, each one defined as a VirtualHost entry in
14081 Prosody's configuration. Conversely a server that hosts a single domain would
14082 have just one VirtualHost entry.
14084 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
14086 Available @code{virtualhost-configuration} fields are:
14088 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
14089 @deftypevr {@code{virtualhost-configuration} parameter} string domain
14090 Domain you wish Prosody to serve.
14095 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
14096 Components are extra services on a server which are available to clients,
14097 usually on a subdomain of the main server (such as
14098 @samp{"mycomponent.example.com"}). Example components might be chatroom
14099 servers, user directories, or gateways to other protocols.
14101 Internal components are implemented with Prosody-specific plugins. To add an
14102 internal component, you simply fill the hostname field, and the plugin you wish
14103 to use for the component.
14105 See @url{http://prosody.im/doc/components}.
14106 Defaults to @samp{()}.
14108 Available @code{int-component-configuration} fields are:
14110 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
14111 @deftypevr {@code{int-component-configuration} parameter} string hostname
14112 Hostname of the component.
14115 @deftypevr {@code{int-component-configuration} parameter} string plugin
14116 Plugin you wish to use for the component.
14119 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
14120 Multi-user chat (MUC) is Prosody's module for allowing you to create
14121 hosted chatrooms/conferences for XMPP users.
14123 General information on setting up and using multi-user chatrooms can be found
14124 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
14125 which you should read if you are new to XMPP chatrooms.
14127 See also @url{http://prosody.im/doc/modules/mod_muc}.
14129 Available @code{mod-muc-configuration} fields are:
14131 @deftypevr {@code{mod-muc-configuration} parameter} string name
14132 The name to return in service discovery responses.
14133 Defaults to @samp{"Prosody Chatrooms"}.
14136 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
14137 If @samp{#t}, this will only allow admins to create new chatrooms.
14138 Otherwise anyone can create a room. The value @samp{"local"} restricts room
14139 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
14140 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
14141 restricts to service administrators only.
14142 Defaults to @samp{#f}.
14145 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
14146 Maximum number of history messages that will be sent to the member that has
14147 just joined the room.
14148 Defaults to @samp{20}.
14155 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
14156 External components use XEP-0114, which most standalone components
14157 support. To add an external component, you simply fill the hostname field. See
14158 @url{http://prosody.im/doc/components}.
14159 Defaults to @samp{()}.
14161 Available @code{ext-component-configuration} fields are:
14163 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
14164 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
14165 Password which the component will use to log in.
14168 @deftypevr {@code{ext-component-configuration} parameter} string hostname
14169 Hostname of the component.
14174 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
14175 Port(s) Prosody listens on for component connections.
14178 @deftypevr {@code{prosody-configuration} parameter} string component-interface
14179 Interface Prosody listens on for component connections.
14180 Defaults to @samp{"127.0.0.1"}.
14183 It could be that you just want to get a @code{prosody.cfg.lua}
14184 up and running. In that case, you can pass an
14185 @code{opaque-prosody-configuration} record as the value of
14186 @code{prosody-service-type}. As its name indicates, an opaque configuration
14187 does not have easy reflective capabilities.
14188 Available @code{opaque-prosody-configuration} fields are:
14190 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
14191 The prosody package.
14194 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
14195 The contents of the @code{prosody.cfg.lua} to use.
14198 For example, if your @code{prosody.cfg.lua} is just the empty
14199 string, you could instantiate a prosody service like this:
14202 (service prosody-service-type
14203 (opaque-prosody-configuration
14204 (prosody.cfg.lua "")))
14208 @node Telephony Services
14209 @subsubsection Telephony Services
14211 @cindex Murmur (VoIP server)
14212 @cindex VoIP server
14213 This section describes how to set up and run a Murmur server. Murmur is
14214 the server of the @uref{https://mumble.info, Mumble} voice-over-IP
14217 @deftp {Data Type} murmur-configuration
14218 The service type for the Murmur server. An example configuration can
14222 (service murmur-service-type
14223 (murmur-configuration
14225 "Welcome to this Mumble server running on GuixSD!")
14226 (cert-required? #t) ;disallow text password logins
14227 (ssl-cert "/etc/letsencrypt/live/mumble.example.com/fullchain.pem")
14228 (ssl-key "/etc/letsencrypt/live/mumble.example.com/privkey.pem")))
14231 After reconfiguring your system, you can manually set the murmur @code{SuperUser}
14232 password with the command that is printed during the activation phase.
14234 It is recommended to register a normal Mumble user account
14235 and grant it admin or moderator rights.
14236 You can use the @code{mumble} client to
14237 login as new normal user, register yourself, and log out.
14238 For the next step login with the name @code{SuperUser} use
14239 the @code{SuperUser} password that you set previously,
14240 and grant your newly registered mumble user administrator or moderator
14241 rights and create some channels.
14243 Available @code{murmur-configuration} fields are:
14246 @item @code{package} (default: @code{mumble})
14247 Package that contains @code{bin/murmurd}.
14249 @item @code{user} (default: @code{"murmur"})
14250 User who will run the Murmur server.
14252 @item @code{group} (default: @code{"murmur"})
14253 Group of the user who will run the murmur server.
14255 @item @code{port} (default: @code{64738})
14256 Port on which the server will listen.
14258 @item @code{welcome-text} (default: @code{""})
14259 Welcome text sent to clients when they connect.
14261 @item @code{server-password} (default: @code{""})
14262 Password the clients have to enter in order to connect.
14264 @item @code{max-users} (default: @code{100})
14265 Maximum of users that can be connected to the server at once.
14267 @item @code{max-user-bandwidth} (default: @code{#f})
14268 Maximum voice traffic a user can send per second.
14270 @item @code{database-file} (default: @code{"/var/lib/murmur/db.sqlite"})
14271 File name of the sqlite database.
14272 The service's user will become the owner of the directory.
14274 @item @code{log-file} (default: @code{"/var/log/murmur/murmur.log"})
14275 File name of the log file.
14276 The service's user will become the owner of the directory.
14278 @item @code{autoban-attempts} (default: @code{10})
14279 Maximum number of logins a user can make in @code{autoban-timeframe}
14280 without getting auto banned for @code{autoban-time}.
14282 @item @code{autoban-timeframe} (default: @code{120})
14283 Timeframe for autoban in seconds.
14285 @item @code{autoban-time} (default: @code{300})
14286 Amount of time in seconds for which a client gets banned
14287 when violating the autoban limits.
14289 @item @code{opus-threshold} (default: @code{100})
14290 Percentage of clients that need to support opus
14291 before switching over to opus audio codec.
14293 @item @code{channel-nesting-limit} (default: @code{10})
14294 How deep channels can be nested at maximum.
14296 @item @code{channelname-regex} (default: @code{#f})
14297 A string in from of a Qt regular expression that channel names must conform to.
14299 @item @code{username-regex} (default: @code{#f})
14300 A string in from of a Qt regular expression that user names must conform to.
14302 @item @code{text-message-length} (default: @code{5000})
14303 Maximum size in bytes that a user can send in one text chat message.
14305 @item @code{image-message-length} (default: @code{(* 128 1024)})
14306 Maximum size in bytes that a user can send in one image message.
14308 @item @code{cert-required?} (default: @code{#f})
14309 If it is set to @code{#t} clients that use weak password authentification
14310 will not be accepted. Users must have completed the certificate wizard to join.
14312 @item @code{remember-channel?} (defualt @code{#f})
14313 Should murmur remember the last channel each user was in when they disconnected
14314 and put them into the remembered channel when they rejoin.
14316 @item @code{allow-html?} (default: @code{#f})
14317 Should html be allowed in text messages, user comments, and channel descriptions.
14319 @item @code{allow-ping?} (default: @code{#f})
14320 Setting to true exposes the current user count, the maximum user count, and
14321 the server's maximum bandwidth per client to unauthenticated users. In the
14322 Mumble client, this information is shown in the Connect dialog.
14324 Disabling this setting will prevent public listing of the server.
14326 @item @code{bonjour?} (default: @code{#f})
14327 Should the server advertise itself in the local network through the bonjour protocol.
14329 @item @code{send-version?} (default: @code{#f})
14330 Should the murmur server version be exposed in ping requests.
14332 @item @code{log-days} (default: @code{31})
14333 Murmur also stores logs in the database, which are accessible via RPC.
14334 The default is 31 days of months, but you can set this setting to 0 to keep logs forever,
14335 or -1 to disable logging to the database.
14337 @item @code{obfuscate-ips?} (default @code{#t})
14338 Should logged ips be obfuscated to protect the privacy of users.
14340 @item @code{ssl-cert} (default: @code{#f})
14341 File name of the SSL/TLS certificate used for encrypted connections.
14344 (ssl-cert "/etc/letsencrypt/live/example.com/fullchain.pem")
14346 @item @code{ssl-key} (default: @code{#f})
14347 Filepath to the ssl private key used for encrypted connections.
14349 (ssl-key "/etc/letsencrypt/live/example.com/privkey.pem")
14352 @item @code{ssl-dh-params} (default: @code{#f})
14353 File name of a PEM-encoded file with Diffie-Hellman parameters
14354 for the SSL/TLS encryption. Alternatively you set it to
14355 @code{"@@ffdhe2048"}, @code{"@@ffdhe3072"}, @code{"@@ffdhe4096"}, @code{"@@ffdhe6144"}
14356 or @code{"@@ffdhe8192"} to use bundled parameters from RFC 7919.
14358 @item @code{ssl-ciphers} (default: @code{#f})
14359 The @code{ssl-ciphers} option chooses the cipher suites to make available for use
14362 This option is specified using
14363 @uref{https://www.openssl.org/docs/apps/ciphers.html#CIPHER-LIST-FORMAT,
14364 OpenSSL cipher list notation}.
14366 It is recommended that you try your cipher string using 'openssl ciphers <string>'
14367 before setting it here, to get a feel for which cipher suites you will get.
14368 After setting this option, it is recommend that you inspect your Murmur log
14369 to ensure that Murmur is using the cipher suites that you expected it to.
14371 Note: Changing this option may impact the backwards compatibility of your
14372 Murmur server, and can remove the ability for older Mumble clients to be able
14375 @item @code{public-registration} (default: @code{#f})
14376 Must be a @code{<murmur-public-registration-configuration>} record or @code{#f}.
14378 You can optionally register your server in the public server list that the
14379 @code{mumble} client shows on startup.
14380 You cannot register your server if you have set a @code{server-password},
14381 or set @code{allow-ping} to @code{#f}.
14383 It might take a few hours until it shows up in the public list.
14385 @item @code{file} (default: @code{#f})
14386 Optional alternative override for this configuration.
14390 @deftp {Data Type} murmur-public-registration-configuration
14391 Configuration for public registration of a murmur service.
14395 This is a display name for your server. Not to be confused with the hostname.
14397 @item @code{password}
14398 A password to identify your registration.
14399 Subsequent updates will need the same password. Don't lose your password.
14402 This should be a @code{http://} or @code{https://} link to your web
14405 @item @code{hostname} (default: @code{#f})
14406 By default your server will be listed by its IP address.
14407 If it is set your server will be linked by this host name instead.
14413 @node Monitoring Services
14414 @subsubsection Monitoring Services
14416 @subsubheading Tailon Service
14418 @uref{https://tailon.readthedocs.io/, Tailon} is a web application for
14419 viewing and searching log files.
14421 The following example will configure the service with default values.
14422 By default, Tailon can be accessed on port 8080 (@code{http://localhost:8080}).
14425 (service tailon-service-type)
14428 The following example customises more of the Tailon configuration,
14429 adding @command{sed} to the list of allowed commands.
14432 (service tailon-service-type
14433 (tailon-configuration
14435 (tailon-configuration-file
14436 (allowed-commands '("tail" "grep" "awk" "sed"))))))
14440 @deftp {Data Type} tailon-configuration
14441 Data type representing the configuration of Tailon.
14442 This type has the following parameters:
14445 @item @code{config-file} (default: @code{(tailon-configuration-file)})
14446 The configuration file to use for Tailon. This can be set to a
14447 @dfn{tailon-configuration-file} record value, or any gexp
14448 (@pxref{G-Expressions}).
14450 For example, to instead use a local file, the @code{local-file} function
14454 (service tailon-service-type
14455 (tailon-configuration
14456 (config-file (local-file "./my-tailon.conf"))))
14459 @item @code{package} (default: @code{tailon})
14460 The tailon package to use.
14465 @deftp {Data Type} tailon-configuration-file
14466 Data type representing the configuration options for Tailon.
14467 This type has the following parameters:
14470 @item @code{files} (default: @code{(list "/var/log")})
14471 List of files to display. The list can include strings for a single file
14472 or directory, or a list, where the first item is the name of a
14473 subsection, and the remaining items are the files or directories in that
14476 @item @code{bind} (default: @code{"localhost:8080"})
14477 Address and port to which Tailon should bind on.
14479 @item @code{relative-root} (default: @code{#f})
14480 URL path to use for Tailon, set to @code{#f} to not use a path.
14482 @item @code{allow-transfers?} (default: @code{#t})
14483 Allow downloading the log files in the web interface.
14485 @item @code{follow-names?} (default: @code{#t})
14486 Allow tailing of not-yet existent files.
14488 @item @code{tail-lines} (default: @code{200})
14489 Number of lines to read initially from each file.
14491 @item @code{allowed-commands} (default: @code{(list "tail" "grep" "awk")})
14492 Commands to allow running. By default, @code{sed} is disabled.
14494 @item @code{debug?} (default: @code{#f})
14495 Set @code{debug?} to @code{#t} to show debug messages.
14497 @item @code{wrap-lines} (default: @code{#t})
14498 Initial line wrapping state in the web interface. Set to @code{#t} to
14499 initially wrap lines (the default), or to @code{#f} to initially not
14502 @item @code{http-auth} (default: @code{#f})
14503 HTTP authentication type to use. Set to @code{#f} to disable
14504 authentication (the default). Supported values are @code{"digest"} or
14507 @item @code{users} (default: @code{#f})
14508 If HTTP authentication is enabled (see @code{http-auth}), access will be
14509 restricted to the credentials provided here. To configure users, use a
14510 list of pairs, where the first element of the pair is the username, and
14511 the 2nd element of the pair is the password.
14514 (tailon-configuration-file
14515 (http-auth "basic")
14516 (users '(("user1" . "password1")
14517 ("user2" . "password2"))))
14524 @node Kerberos Services
14525 @subsubsection Kerberos Services
14528 The @code{(gnu services kerberos)} module provides services relating to
14529 the authentication protocol @dfn{Kerberos}.
14531 @subsubheading Krb5 Service
14533 Programs using a Kerberos client library normally
14534 expect a configuration file in @file{/etc/krb5.conf}.
14535 This service generates such a file from a definition provided in the
14536 operating system declaration.
14537 It does not cause any daemon to be started.
14539 No ``keytab'' files are provided by this service---you must explicitly create them.
14540 This service is known to work with the MIT client library, @code{mit-krb5}.
14541 Other implementations have not been tested.
14543 @defvr {Scheme Variable} krb5-service-type
14544 A service type for Kerberos 5 clients.
14548 Here is an example of its use:
14550 (service krb5-service-type
14551 (krb5-configuration
14552 (default-realm "EXAMPLE.COM")
14553 (allow-weak-crypto? #t)
14556 (name "EXAMPLE.COM")
14557 (admin-server "groucho.example.com")
14558 (kdc "karl.example.com"))
14561 (admin-server "kerb-admin.argrx.edu")
14562 (kdc "keys.argrx.edu"))))))
14566 This example provides a Kerberos@tie{}5 client configuration which:
14568 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
14569 of which have distinct administration servers and key distribution centers;
14570 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
14571 specified by clients;
14572 @item Accepts services which only support encryption types known to be weak.
14575 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
14576 Only the most commonly used ones are described here.
14577 For a full list, and more detailed explanation of each, see the MIT
14578 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
14582 @deftp {Data Type} krb5-realm
14583 @cindex realm, kerberos
14586 This field is a string identifying the name of the realm.
14587 A common convention is to use the fully qualified DNS name of your organization,
14588 converted to upper case.
14590 @item @code{admin-server}
14591 This field is a string identifying the host where the administration server is
14595 This field is a string identifying the key distribution center
14600 @deftp {Data Type} krb5-configuration
14603 @item @code{allow-weak-crypto?} (default: @code{#f})
14604 If this flag is @code{#t} then services which only offer encryption algorithms
14605 known to be weak will be accepted.
14607 @item @code{default-realm} (default: @code{#f})
14608 This field should be a string identifying the default Kerberos
14609 realm for the client.
14610 You should set this field to the name of your Kerberos realm.
14611 If this value is @code{#f}
14612 then a realm must be specified with every Kerberos principal when invoking programs
14613 such as @command{kinit}.
14615 @item @code{realms}
14616 This should be a non-empty list of @code{krb5-realm} objects, which clients may
14618 Normally, one of them will have a @code{name} field matching the @code{default-realm}
14624 @subsubheading PAM krb5 Service
14627 The @code{pam-krb5} service allows for login authentication and password
14628 management via Kerberos.
14629 You will need this service if you want PAM enabled applications to authenticate
14630 users using Kerberos.
14632 @defvr {Scheme Variable} pam-krb5-service-type
14633 A service type for the Kerberos 5 PAM module.
14636 @deftp {Data Type} pam-krb5-configuration
14637 Data type representing the configuration of the Kerberos 5 PAM module
14638 This type has the following parameters:
14640 @item @code{pam-krb5} (default: @code{pam-krb5})
14641 The pam-krb5 package to use.
14643 @item @code{minimum-uid} (default: @code{1000})
14644 The smallest user ID for which Kerberos authentications should be attempted.
14645 Local accounts with lower values will silently fail to authenticate.
14651 @subsubsection Web Services
14656 The @code{(gnu services web)} module provides the nginx web server and
14657 also a fastcgi wrapper daemon.
14659 @deffn {Scheme Variable} nginx-service-type
14660 Service type for the @uref{https://nginx.org/,NGinx} web server. The
14661 value for this service type is a @code{<nginx-configuration>} record.
14663 A simple example configuration is given below.
14666 (service nginx-service-type
14667 (nginx-configuration
14669 (list (nginx-server-configuration
14670 (server-name '("www.example.com"))
14671 (root "/srv/http/www.example.com")
14673 (ssl-certificate #f)
14674 (ssl-certificate-key #f))))))
14677 In addition to adding server blocks to the service configuration
14678 directly, this service can be extended by other services to add server
14679 blocks, as in this example:
14682 (simple-service 'my-extra-server nginx-service-type
14683 (list (nginx-server-configuration
14685 (ssl-certificate #f)
14686 (ssl-certificate-key #f)
14687 (root "/srv/http/extra-website")
14688 (try-files (list "$uri" "$uri/index.html")))))
14692 At startup, @command{nginx} has not yet read its configuration file, so
14693 it uses a default file to log error messages. If it fails to load its
14694 configuration file, that is where error messages are logged. After the
14695 configuration file is loaded, the default error log file changes as per
14696 configuration. In our case, startup error messages can be found in
14697 @file{/var/run/nginx/logs/error.log}, and after configuration in
14698 @file{/var/log/nginx/error.log}. The second location can be changed
14699 with the @var{log-directory} configuration option.
14701 @deffn {Data Type} nginx-configuration
14702 This data type represents the configuration for NGinx. Some
14703 configuration can be done through this and the other provided record
14704 types, or alternatively, a config file can be provided.
14707 @item @code{nginx} (default: @code{nginx})
14708 The nginx package to use.
14710 @item @code{log-directory} (default: @code{"/var/log/nginx"})
14711 The directory to which NGinx will write log files.
14713 @item @code{run-directory} (default: @code{"/var/run/nginx"})
14714 The directory in which NGinx will create a pid file, and write temporary
14717 @item @code{server-blocks} (default: @code{'()})
14718 A list of @dfn{server blocks} to create in the generated configuration
14719 file, the elements should be of type
14720 @code{<nginx-server-configuration>}.
14722 The following example would setup NGinx to serve @code{www.example.com}
14723 from the @code{/srv/http/www.example.com} directory, without using
14726 (service nginx-service-type
14727 (nginx-configuration
14729 (list (nginx-server-configuration
14730 (server-name '("www.example.com"))
14731 (root "/srv/http/www.example.com")
14733 (ssl-certificate #f)
14734 (ssl-certificate-key #f))))))
14737 @item @code{upstream-blocks} (default: @code{'()})
14738 A list of @dfn{upstream blocks} to create in the generated configuration
14739 file, the elements should be of type
14740 @code{<nginx-upstream-configuration>}.
14742 Configuring upstreams through the @code{upstream-blocks} can be useful
14743 when combined with @code{locations} in the
14744 @code{<nginx-server-configuration>} records. The following example
14745 creates a server configuration with one location configuration, that
14746 will proxy requests to a upstream configuration, which will handle
14747 requests with two servers.
14752 (nginx-configuration
14754 (list (nginx-server-configuration
14755 (server-name '("www.example.com"))
14756 (root "/srv/http/www.example.com")
14758 (ssl-certificate #f)
14759 (ssl-certificate-key #f)
14762 (nginx-location-configuration
14764 (body '("proxy_pass http://server-proxy;"))))))))
14766 (list (nginx-upstream-configuration
14767 (name "server-proxy")
14768 (servers (list "server1.example.com"
14769 "server2.example.com")))))))
14772 @item @code{file} (default: @code{#f})
14773 If a configuration @var{file} is provided, this will be used, rather than
14774 generating a configuration file from the provided @code{log-directory},
14775 @code{run-directory}, @code{server-blocks} and @code{upstream-blocks}. For
14776 proper operation, these arguments should match what is in @var{file} to ensure
14777 that the directories are created when the service is activated.
14779 This can be useful if you have an existing configuration file, or it's
14780 not possible to do what is required through the other parts of the
14781 nginx-configuration record.
14786 @deftp {Data Type} nginx-server-configuration
14787 Data type representing the configuration of an nginx server block.
14788 This type has the following parameters:
14791 @item @code{http-port} (default: @code{80})
14792 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
14793 nginx should not listen for HTTP (non secure) connection for this
14794 @dfn{server block}.
14796 @item @code{https-port} (default: @code{443})
14797 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
14798 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
14800 Note that nginx can listen for HTTP and HTTPS connections in the same
14801 @dfn{server block}.
14803 @item @code{server-name} (default: @code{(list 'default)})
14804 A list of server names this server represents. @code{'default} represents the
14805 default server for connections matching no other server.
14807 @item @code{root} (default: @code{"/srv/http"})
14808 Root of the website nginx will serve.
14810 @item @code{locations} (default: @code{'()})
14811 A list of @dfn{nginx-location-configuration} or
14812 @dfn{nginx-named-location-configuration} records to use within this
14815 @item @code{index} (default: @code{(list "index.html")})
14816 Index files to look for when clients ask for a directory. If it cannot be found,
14817 Nginx will send the list of files in the directory.
14819 @item @code{try-files} (default: @code{'()})
14820 A list of files whose existence is checked in the specified order.
14821 @code{nginx} will use the first file it finds to process the request.
14823 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
14824 Where to find the certificate for secure connections. Set it to @code{#f} if
14825 you don't have a certificate or you don't want to use HTTPS.
14827 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
14828 Where to find the private key for secure connections. Set it to @code{#f} if
14829 you don't have a key or you don't want to use HTTPS.
14831 @item @code{server-tokens?} (default: @code{#f})
14832 Whether the server should add its configuration to response.
14837 @deftp {Data Type} nginx-upstream-configuration
14838 Data type representing the configuration of an nginx @code{upstream}
14839 block. This type has the following parameters:
14843 Name for this group of servers.
14845 @item @code{servers}
14846 Specify the addresses of the servers in the group. The address can be
14847 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
14848 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
14849 prefix @samp{unix:}. For addresses using an IP address or domain name,
14850 the default port is 80, and a different port can be specified
14856 @deftp {Data Type} nginx-location-configuration
14857 Data type representing the configuration of an nginx @code{location}
14858 block. This type has the following parameters:
14862 URI which this location block matches.
14864 @anchor{nginx-location-configuration body}
14866 Body of the location block, specified as a string. This can contain many
14867 configuration directives. For example, to pass requests to a upstream
14868 server group defined using an @code{nginx-upstream-configuration} block,
14869 the following directive would be specified in the body @samp{proxy_pass
14870 http://upstream-name;}.
14875 @deftp {Data Type} nginx-named-location-configuration
14876 Data type representing the configuration of an nginx named location
14877 block. Named location blocks are used for request redirection, and not
14878 used for regular request processing. This type has the following
14883 Name to identify this location block.
14886 @xref{nginx-location-configuration body}, as the body for named location
14887 blocks can be used in a similar way to the
14888 @code{nginx-location-configuration body}. One restriction is that the
14889 body of a named location block cannot contain location blocks.
14896 FastCGI is an interface between the front-end and the back-end of a web
14897 service. It is a somewhat legacy facility; new web services should
14898 generally just talk HTTP between the front-end and the back-end.
14899 However there are a number of back-end services such as PHP or the
14900 optimized HTTP Git repository access that use FastCGI, so we have
14901 support for it in Guix.
14903 To use FastCGI, you configure the front-end web server (e.g., nginx) to
14904 dispatch some subset of its requests to the fastcgi backend, which
14905 listens on a local TCP or UNIX socket. There is an intermediary
14906 @code{fcgiwrap} program that sits between the actual backend process and
14907 the web server. The front-end indicates which backend program to run,
14908 passing that information to the @code{fcgiwrap} process.
14910 @defvr {Scheme Variable} fcgiwrap-service-type
14911 A service type for the @code{fcgiwrap} FastCGI proxy.
14914 @deftp {Data Type} fcgiwrap-configuration
14915 Data type representing the configuration of the @code{fcgiwrap} serice.
14916 This type has the following parameters:
14918 @item @code{package} (default: @code{fcgiwrap})
14919 The fcgiwrap package to use.
14921 @item @code{socket} (default: @code{tcp:127.0.0.1:9000})
14922 The socket on which the @code{fcgiwrap} process should listen, as a
14923 string. Valid @var{socket} values include
14924 @code{unix:@var{/path/to/unix/socket}},
14925 @code{tcp:@var{dot.ted.qu.ad}:@var{port}} and
14926 @code{tcp6:[@var{ipv6_addr}]:port}.
14928 @item @code{user} (default: @code{fcgiwrap})
14929 @itemx @code{group} (default: @code{fcgiwrap})
14930 The user and group names, as strings, under which to run the
14931 @code{fcgiwrap} process. The @code{fastcgi} service will ensure that if
14932 the user asks for the specific user or group names @code{fcgiwrap} that
14933 the corresponding user and/or group is present on the system.
14935 It is possible to configure a FastCGI-backed web service to pass HTTP
14936 authentication information from the front-end to the back-end, and to
14937 allow @code{fcgiwrap} to run the back-end process as a corresponding
14938 local user. To enable this capability on the back-end., run
14939 @code{fcgiwrap} as the @code{root} user and group. Note that this
14940 capability also has to be configured on the front-end as well.
14946 @subsubsection DNS Services
14947 @cindex DNS (domain name system)
14948 @cindex domain name system (DNS)
14950 The @code{(gnu services dns)} module provides services related to the
14951 @dfn{domain name system} (DNS). It provides a server service for hosting
14952 an @emph{authoritative} DNS server for multiple zones, slave or master.
14953 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
14955 An example configuration of an authoritative server for two zones, one master
14959 (define-zone-entries example.org.zone
14960 ;; Name TTL Class Type Data
14961 ("@@" "" "IN" "A" "127.0.0.1")
14962 ("@@" "" "IN" "NS" "ns")
14963 ("ns" "" "IN" "A" "127.0.0.1"))
14965 (define master-zone
14966 (knot-zone-configuration
14967 (domain "example.org")
14969 (origin "example.org")
14970 (entries example.org.zone)))))
14973 (knot-zone-configuration
14974 (domain "plop.org")
14975 (dnssec-policy "default")
14976 (master (list "plop-master"))))
14978 (define plop-master
14979 (knot-remote-configuration
14981 (address (list "208.76.58.171"))))
14985 (services (cons* (service knot-service-type
14986 (knot-confifguration
14987 (remotes (list plop-master))
14988 (zones (list master-zone slave-zone))))
14993 @deffn {Scheme Variable} knot-service-type
14994 This is the type for the Knot DNS server.
14996 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
14997 zones, that is to say domain names you would buy from a registrar. This server
14998 is not a resolver, meaning that it can only resolve names for which it is
14999 authoritative. This server can be configured to serve zones as a master server
15000 or a slave server as a per-zone basis. Slave zones will get their data from
15001 masters, and will serve it as an authoritative server. From the point of view
15002 of a resolver, there is no difference between master and slave.
15004 The following data types are used to configure the Knot DNS server:
15007 @deftp {Data Type} knot-key-configuration
15008 Data type representing a key.
15009 This type has the following parameters:
15012 @item @code{id} (default: @code{""})
15013 An identifier for other configuration fields to refer to this key. IDs must
15014 be unique and must not be empty.
15016 @item @code{algorithm} (default: @code{#f})
15017 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
15018 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
15019 and @code{'hmac-sha512}.
15021 @item @code{secret} (default: @code{""})
15022 The secret key itself.
15027 @deftp {Data Type} knot-acl-configuration
15028 Data type representing an Access Control List (ACL) configuration.
15029 This type has the following parameters:
15032 @item @code{id} (default: @code{""})
15033 An identifier for ether configuration fields to refer to this key. IDs must be
15034 unique and must not be empty.
15036 @item @code{address} (default: @code{'()})
15037 An ordered list of IP addresses, network subnets, or network ranges represented
15038 with strings. The query must match one of them. Empty value means that
15039 address match is not required.
15041 @item @code{key} (default: @code{'()})
15042 An ordered list of references to keys represented with strings. The string
15043 must match a key ID defined in a @code{knot-key-configuration}. No key means
15044 that a key is not require to match that ACL.
15046 @item @code{action} (default: @code{'()})
15047 An ordered list of actions that are permitted or forbidden by this ACL. Possible
15048 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
15049 and @code{'update}.
15051 @item @code{deny?} (default: @code{#f})
15052 When true, the ACL defines restrictions. Listed actions are forbidden. When
15053 false, listed actions are allowed.
15058 @deftp {Data Type} zone-entry
15059 Data type represnting a record entry in a zone file.
15060 This type has the following parameters:
15063 @item @code{name} (default: @code{"@@"})
15064 The name of the record. @code{"@@"} refers to the origin of the zone. Names
15065 are relative to the origin of the zone. For example, in the @code{example.org}
15066 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
15067 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
15068 refers to @code{ns.example.org}.
15070 @item @code{ttl} (default: @code{""})
15071 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
15073 @item @code{class} (default: @code{"IN"})
15074 The class of the record. Knot currently supports only @code{"IN"} and
15075 partially @code{"CH"}.
15077 @item @code{type} (default: @code{"A"})
15078 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
15079 address), NS (Name Server) and MX (Mail eXchange). Many other types are
15082 @item @code{data} (default: @code{""})
15083 The data contained in the record. For instance an IP address associated with
15084 an A record, or a domain name associated with an NS record. Remember that
15085 domain names are relative to the origin unless they end with a dot.
15090 @deftp {Data Type} zone-file
15091 Data type representing the content of a zone file.
15092 This type has the following parameters:
15095 @item @code{entries} (default: @code{'()})
15096 The list of entries. The SOA record is taken care of, so you don't need to
15097 put it in the list of entries. This list should probably contain an entry
15098 for your primary authoritative DNS server. Other than using a list of entries
15099 directly, you can use @code{define-zone-entries} to define a object containing
15100 the list of entries more easily, that you can later pass to the @code{entries}
15101 field of the @code{zone-file}.
15103 @item @code{origin} (default: @code{""})
15104 The name of your zone. This parameter cannot be empty.
15106 @item @code{ns} (default: @code{"ns"})
15107 The domain of your primary authoritative DNS server. The name is relative to
15108 the origin, unless it ends with a dot. It is mandatory that this primary
15109 DNS server corresponds to an NS record in the zone and that it is associated
15110 to an IP address in the list of entries.
15112 @item @code{mail} (default: @code{"hostmaster"})
15113 An email address people can contact you at, as the owner of the zone. This
15114 is translated as @code{<mail>@@<origin>}.
15116 @item @code{serial} (default: @code{1})
15117 The serial number of the zone. As this is used to keep track of changes by
15118 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
15119 Always increment it when you make a change in your zone.
15121 @item @code{refresh} (default: @code{(* 2 24 3600)})
15122 The frequency at which slaves will do a zone transfer. This value is a number
15123 of seconds. It can be computed by multiplications or with
15124 @code{(string->duration)}.
15126 @item @code{retry} (default: @code{(* 15 60)})
15127 The period after which a slave will retry to contact its master when it fails
15128 to do so a first time.
15130 @item @code{expiry} (default: @code{(* 14 24 3600)})
15131 Default TTL of records. Existing records are considered correct for at most
15132 this amount of time. After this period, resolvers will invalidate their cache
15133 and check again that it still exists.
15135 @item @code{nx} (default: @code{3600})
15136 Default TTL of inexistant records. This delay is usually short because you want
15137 your new domains to reach everyone quickly.
15142 @deftp {Data Type} knot-remote-configuration
15143 Data type representing a remote configuration.
15144 This type has the following parameters:
15147 @item @code{id} (default: @code{""})
15148 An identifier for other configuration fields to refer to this remote. IDs must
15149 be unique and must not be empty.
15151 @item @code{address} (default: @code{'()})
15152 An ordered list of destination IP addresses. Addresses are tried in sequence.
15153 An optional port can be given with the @@ separator. For instance:
15154 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
15156 @item @code{via} (default: @code{'()})
15157 An ordered list of source IP addresses. An empty list will have Knot choose
15158 an appropriate source IP. An optional port can be given with the @@ separator.
15159 The default is to choose at random.
15161 @item @code{key} (default: @code{#f})
15162 A reference to a key, that is a string containing the identifier of a key
15163 defined in a @code{knot-key-configuration} field.
15168 @deftp {Data Type} knot-keystore-configuration
15169 Data type representing a keystore to hold dnssec keys.
15170 This type has the following parameters:
15173 @item @code{id} (default: @code{""})
15174 The id of the keystore. It must not be empty.
15176 @item @code{backend} (default: @code{'pem})
15177 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
15179 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
15180 The configuration string of the backend. An example for the PKCS#11 is:
15181 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
15182 For the pem backend, the string reprensents a path in the filesystem.
15187 @deftp {Data Type} knot-policy-configuration
15188 Data type representing a dnssec policy. Knot DNS is able to automatically
15189 sign your zones. It can either generate and manage your keys automatically or
15190 use keys that you generate.
15192 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
15193 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
15194 zone. In order to be trusted, the KSK needs to be present in the parent zone
15195 (usually a top-level domain). If your registrar supports dnssec, you will
15196 have to send them your KSK's hash so they can add a DS record in their zone.
15197 This is not automated and need to be done each time you change your KSK.
15199 The policy also defines the lifetime of keys. Usually, ZSK can be changed
15200 easily and use weaker cryptographic functions (they use lower parameters) in
15201 order to sign records quickly, so they are changed often. The KSK however
15202 requires manual interaction with the registrar, so they are changed less often
15203 and use stronger parameters because they sign only one record.
15205 This type has the following parameters:
15208 @item @code{id} (default: @code{""})
15209 The id of the policy. It must not be empty.
15211 @item @code{keystore} (default: @code{"default"})
15212 A reference to a keystore, that is a string containing the identifier of a
15213 keystore defined in a @code{knot-keystore-configuration} field. The
15214 @code{"default"} identifier means the default keystore (a kasp database that
15215 was setup by this service).
15217 @item @code{manual?} (default: @code{#f})
15218 Whether the key management is manual or automatic.
15220 @item @code{single-type-signing?} (default: @code{#f})
15221 When @code{#t}, use the Single-Type Signing Scheme.
15223 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
15224 An algorithm of signing keys and issued signatures.
15226 @item @code{ksk-size} (default: @code{256})
15227 The length of the KSK. Note that this value is correct for the default
15228 algorithm, but would be unsecure for other algorithms.
15230 @item @code{zsk-size} (default: @code{256})
15231 The length of the ZSK. Note that this value is correct for the default
15232 algorithm, but would be unsecure for other algorithms.
15234 @item @code{dnskey-ttl} (default: @code{'default})
15235 The TTL value for DNSKEY records added into zone apex. The special
15236 @code{'default} value means same as the zone SOA TTL.
15238 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
15239 The period between ZSK publication and the next rollover initiation.
15241 @item @code{propagation-delay} (default: @code{(* 24 3600)})
15242 An extra delay added for each key rollover step. This value should be high
15243 enough to cover propagation of data from the master server to all slaves.
15245 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
15246 A validity period of newly issued signatures.
15248 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
15249 A period how long before a signature expiration the signature will be refreshed.
15251 @item @code{nsec3?} (default: @code{#f})
15252 When @code{#t}, NSEC3 will be used instead of NSEC.
15254 @item @code{nsec3-iterations} (default: @code{5})
15255 The number of additional times the hashing is performed.
15257 @item @code{nsec3-salt-length} (default: @code{8})
15258 The length of a salt field in octets, which is appended to the original owner
15259 name before hashing.
15261 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
15262 The validity period of newly issued salt field.
15267 @deftp {Data Type} knot-zone-configuration
15268 Data type representing a zone served by Knot.
15269 This type has the following parameters:
15272 @item @code{domain} (default: @code{""})
15273 The domain served by this configuration. It must not be empty.
15275 @item @code{file} (default: @code{""})
15276 The file where this zone is saved. This parameter is ignored by master zones.
15277 Empty means default location that depends on the domain name.
15279 @item @code{zone} (default: @code{(zone-file)})
15280 The content of the zone file. This parameter is ignored by slave zones. It
15281 must contain a zone-file record.
15283 @item @code{master} (default: @code{'()})
15284 A list of master remotes. When empty, this zone is a master. When set, this
15285 zone is a slave. This is a list of remotes identifiers.
15287 @item @code{ddns-master} (default: @code{#f})
15288 The main master. When empty, it defaults to the first master in the list of
15291 @item @code{notify} (default: @code{'()})
15292 A list of slave remote identifiers.
15294 @item @code{acl} (default: @code{'()})
15295 A list of acl identifiers.
15297 @item @code{semantic-checks?} (default: @code{#f})
15298 When set, this adds more semantic checks to the zone.
15300 @item @code{disable-any?} (default: @code{#f})
15301 When set, this forbids queries of the ANY type.
15303 @item @code{zonefile-sync} (default: @code{0})
15304 The delay between a modification in memory and on disk. 0 means immediate
15307 @item @code{serial-policy} (default: @code{'increment})
15308 A policy between @code{'increment} and @code{'unixtime}.
15313 @deftp {Data Type} knot-configuration
15314 Data type representing the Knot configuration.
15315 This type has the following parameters:
15318 @item @code{knot} (default: @code{knot})
15321 @item @code{run-directory} (default: @code{"/var/run/knot"})
15322 The run directory. This directory will be used for pid file and sockets.
15324 @item @code{listen-v4} (default: @code{"0.0.0.0"})
15325 An ip address on which to listen.
15327 @item @code{listen-v6} (default: @code{"::"})
15328 An ip address on which to listen.
15330 @item @code{listen-port} (default: @code{53})
15331 A port on which to listen.
15333 @item @code{keys} (default: @code{'()})
15334 The list of knot-key-configuration used by this configuration.
15336 @item @code{acls} (default: @code{'()})
15337 The list of knot-acl-configuration used by this configuration.
15339 @item @code{remotes} (default: @code{'()})
15340 The list of knot-remote-configuration used by this configuration.
15342 @item @code{zones} (default: @code{'()})
15343 The list of knot-zone-configuration used by this configuration.
15349 @subsubsection VPN Services
15350 @cindex VPN (virtual private network)
15351 @cindex virtual private network (VPN)
15353 The @code{(gnu services vpn)} module provides services related to
15354 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
15355 your machine to connect to a VPN, and a @emph{servire} service for your machine
15356 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
15358 @deffn {Scheme Procedure} openvpn-client-service @
15359 [#:config (openvpn-client-configuration)]
15361 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
15364 @deffn {Scheme Procedure} openvpn-server-service @
15365 [#:config (openvpn-server-configuration)]
15367 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
15369 Both can be run simultaneously.
15372 @c %automatically generated documentation
15374 Available @code{openvpn-client-configuration} fields are:
15376 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
15377 The OpenVPN package.
15381 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
15382 The OpenVPN pid file.
15384 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
15388 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
15389 The protocol (UDP or TCP) used to open a channel between clients and
15392 Defaults to @samp{udp}.
15396 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
15397 The device type used to represent the VPN connection.
15399 Defaults to @samp{tun}.
15403 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
15404 The certificate authority to check connections against.
15406 Defaults to @samp{"/etc/openvpn/ca.crt"}.
15410 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
15411 The certificate of the machine the daemon is running on. It should be
15412 signed by the authority given in @code{ca}.
15414 Defaults to @samp{"/etc/openvpn/client.crt"}.
15418 @deftypevr {@code{openvpn-client-configuration} parameter} string key
15419 The key of the machine the daemon is running on. It must be the key whose
15420 certificate is @code{cert}.
15422 Defaults to @samp{"/etc/openvpn/client.key"}.
15426 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
15427 Whether to use the lzo compression algorithm.
15429 Defaults to @samp{#t}.
15433 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
15434 Don't re-read key files across SIGUSR1 or --ping-restart.
15436 Defaults to @samp{#t}.
15440 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
15441 Don't close and reopen TUN/TAP device or run up/down scripts across
15442 SIGUSR1 or --ping-restart restarts.
15444 Defaults to @samp{#t}.
15448 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
15451 Defaults to @samp{3}.
15455 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
15456 Add an additional layer of HMAC authentication on top of the TLS control
15457 channel to protect against DoS attacks.
15459 Defaults to @samp{#f}.
15463 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
15464 Whether to check the server certificate has server usage extension.
15466 Defaults to @samp{#t}.
15470 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
15471 Bind to a specific local port number.
15473 Defaults to @samp{#f}.
15477 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
15478 Retry resolving server address.
15480 Defaults to @samp{#t}.
15484 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
15485 A list of remote servers to connect to.
15487 Defaults to @samp{()}.
15489 Available @code{openvpn-remote-configuration} fields are:
15491 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
15494 Defaults to @samp{"my-server"}.
15498 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
15499 Port number the server listens to.
15501 Defaults to @samp{1194}.
15506 @c %end of automatic openvpn-client documentation
15508 @c %automatically generated documentation
15510 Available @code{openvpn-server-configuration} fields are:
15512 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
15513 The OpenVPN package.
15517 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
15518 The OpenVPN pid file.
15520 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
15524 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
15525 The protocol (UDP or TCP) used to open a channel between clients and
15528 Defaults to @samp{udp}.
15532 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
15533 The device type used to represent the VPN connection.
15535 Defaults to @samp{tun}.
15539 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
15540 The certificate authority to check connections against.
15542 Defaults to @samp{"/etc/openvpn/ca.crt"}.
15546 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
15547 The certificate of the machine the daemon is running on. It should be
15548 signed by the authority given in @code{ca}.
15550 Defaults to @samp{"/etc/openvpn/client.crt"}.
15554 @deftypevr {@code{openvpn-server-configuration} parameter} string key
15555 The key of the machine the daemon is running on. It must be the key whose
15556 certificate is @code{cert}.
15558 Defaults to @samp{"/etc/openvpn/client.key"}.
15562 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
15563 Whether to use the lzo compression algorithm.
15565 Defaults to @samp{#t}.
15569 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
15570 Don't re-read key files across SIGUSR1 or --ping-restart.
15572 Defaults to @samp{#t}.
15576 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
15577 Don't close and reopen TUN/TAP device or run up/down scripts across
15578 SIGUSR1 or --ping-restart restarts.
15580 Defaults to @samp{#t}.
15584 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
15587 Defaults to @samp{3}.
15591 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
15592 Add an additional layer of HMAC authentication on top of the TLS control
15593 channel to protect against DoS attacks.
15595 Defaults to @samp{#f}.
15599 @deftypevr {@code{openvpn-server-configuration} parameter} number port
15600 Specifies the port number on which the server listens.
15602 Defaults to @samp{1194}.
15606 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
15607 An ip and mask specifying the subnet inside the virtual network.
15609 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
15613 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
15614 A CIDR notation specifying the IPv6 subnet inside the virtual network.
15616 Defaults to @samp{#f}.
15620 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
15621 The Diffie-Hellman parameters file.
15623 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
15627 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
15628 The file that records client IPs.
15630 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
15634 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
15635 When true, the server will act as a gateway for its clients.
15637 Defaults to @samp{#f}.
15641 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
15642 When true, clients are allowed to talk to each other inside the VPN.
15644 Defaults to @samp{#f}.
15648 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
15649 Causes ping-like messages to be sent back and forth over the link so
15650 that each side knows when the other side has gone down. @code{keepalive}
15651 requires a pair. The first element is the period of the ping sending,
15652 and the second element is the timeout before considering the other side
15657 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
15658 The maximum number of clients.
15660 Defaults to @samp{100}.
15664 @deftypevr {@code{openvpn-server-configuration} parameter} string status
15665 The status file. This file shows a small report on current connection.
15666 It is truncated and rewritten every minute.
15668 Defaults to @samp{"/var/run/openvpn/status"}.
15672 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
15673 The list of configuration for some clients.
15675 Defaults to @samp{()}.
15677 Available @code{openvpn-ccd-configuration} fields are:
15679 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
15682 Defaults to @samp{"client"}.
15686 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
15689 Defaults to @samp{#f}.
15693 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
15696 Defaults to @samp{#f}.
15703 @c %end of automatic openvpn-server documentation
15706 @node Network File System
15707 @subsubsection Network File System
15710 The @code{(gnu services nfs)} module provides the following services,
15711 which are most commonly used in relation to mounting or exporting
15712 directory trees as @dfn{network file systems} (NFS).
15714 @subsubheading RPC Bind Service
15717 The RPC Bind service provides a facility to map program numbers into
15718 universal addresses.
15719 Many NFS related services use this facility. Hence it is automatically
15720 started when a dependent service starts.
15722 @defvr {Scheme Variable} rpcbind-service-type
15723 A service type for the RPC portmapper daemon.
15727 @deftp {Data Type} rpcbind-configuration
15728 Data type representing the configuration of the RPC Bind Service.
15729 This type has the following parameters:
15731 @item @code{rpcbind} (default: @code{rpcbind})
15732 The rpcbind package to use.
15734 @item @code{warm-start?} (default: @code{#t})
15735 If this parameter is @code{#t}, then the daemon will read a
15736 state file on startup thus reloading state information saved by a previous
15742 @subsubheading Pipefs Pseudo File System
15746 The pipefs file system is used to transfer NFS related data
15747 between the kernel and user space programs.
15749 @defvr {Scheme Variable} pipefs-service-type
15750 A service type for the pipefs pseudo file system.
15753 @deftp {Data Type} pipefs-configuration
15754 Data type representing the configuration of the pipefs pseudo file system service.
15755 This type has the following parameters:
15757 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15758 The directory to which the file system is to be attached.
15763 @subsubheading GSS Daemon Service
15766 @cindex global security system
15768 The @dfn{global security system} (GSS) daemon provides strong security for RPC
15770 Before exchanging RPC requests an RPC client must establish a security
15771 context. Typically this is done using the Kerberos command @command{kinit}
15772 or automatically at login time using PAM services (@pxref{Kerberos Services}).
15774 @defvr {Scheme Variable} gss-service-type
15775 A service type for the Global Security System (GSS) daemon.
15778 @deftp {Data Type} gss-configuration
15779 Data type representing the configuration of the GSS daemon service.
15780 This type has the following parameters:
15782 @item @code{nfs-utils} (default: @code{nfs-utils})
15783 The package in which the @command{rpc.gssd} command is to be found.
15785 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15786 The directory where the pipefs file system is mounted.
15792 @subsubheading IDMAP Daemon Service
15794 @cindex name mapper
15796 The idmap daemon service provides mapping between user IDs and user names.
15797 Typically it is required in order to access file systems mounted via NFSv4.
15799 @defvr {Scheme Variable} idmap-service-type
15800 A service type for the Identity Mapper (IDMAP) daemon.
15803 @deftp {Data Type} idmap-configuration
15804 Data type representing the configuration of the IDMAP daemon service.
15805 This type has the following parameters:
15807 @item @code{nfs-utils} (default: @code{nfs-utils})
15808 The package in which the @command{rpc.idmapd} command is to be found.
15810 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
15811 The directory where the pipefs file system is mounted.
15813 @item @code{domain} (default: @code{#f})
15814 The local NFSv4 domain name.
15815 This must be a string or @code{#f}.
15816 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
15821 @node Continuous Integration
15822 @subsubsection Continuous Integration
15824 @cindex continuous integration
15825 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
15826 integration tool for Guix. It can be used both for development and for
15827 providing substitutes to others (@pxref{Substitutes}).
15829 The @code{(gnu services cuirass)} module provides the following service.
15831 @defvr {Scheme Procedure} cuirass-service-type
15832 The type of the Cuirass service. Its value must be a
15833 @code{cuirass-configuration} object, as described below.
15836 To add build jobs, you have to set the @code{specifications} field of
15837 the configuration. Here is an example of a service defining a build job
15838 based on a specification that can be found in Cuirass source tree. This
15839 service polls the Guix repository and builds a subset of the Guix
15840 packages, as prescribed in the @file{gnu-system.scm} example spec:
15843 (let ((spec #~((#:name . "guix")
15844 (#:url . "git://git.savannah.gnu.org/guix.git")
15845 (#:load-path . ".")
15846 (#:file . "build-aux/cuirass/gnu-system.scm")
15847 (#:proc . cuirass-jobs)
15848 (#:arguments (subset . "hello"))
15849 (#:branch . "master"))))
15850 (service cuirass-service-type
15851 (cuirass-configuration
15852 (specifications #~(list '#$spec)))))
15855 While information related to build jobs is located directly in the
15856 specifications, global settings for the @command{cuirass} process are
15857 accessible in other @code{cuirass-configuration} fields.
15859 @deftp {Data Type} cuirass-configuration
15860 Data type representing the configuration of Cuirass.
15863 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
15864 Location of the log file.
15866 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
15867 Location of the repository cache.
15869 @item @code{user} (default: @code{"cuirass"})
15870 Owner of the @code{cuirass} process.
15872 @item @code{group} (default: @code{"cuirass"})
15873 Owner's group of the @code{cuirass} process.
15875 @item @code{interval} (default: @code{60})
15876 Number of seconds between the poll of the repositories followed by the
15879 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
15880 Location of sqlite database which contains the build results and previously
15881 added specifications.
15883 @item @code{port} (default: @code{8081})
15884 Port number used by the HTTP server.
15886 @item --listen=@var{host}
15887 Listen on the network interface for @var{host}. The default is to
15888 accept connections from localhost.
15890 @item @code{specifications} (default: @code{#~'()})
15891 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
15892 where a specification is an association list
15893 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
15894 keys are keywords (@code{#:keyword-example}) as shown in the example
15897 @item @code{use-substitutes?} (default: @code{#f})
15898 This allows using substitutes to avoid building every dependencies of a job
15901 @item @code{one-shot?} (default: @code{#f})
15902 Only evaluate specifications and build derivations once.
15904 @item @code{fallback?} (default: @code{#f})
15905 When substituting a pre-built binary fails, fall back to building
15908 @item @code{load-path} (default: @code{'()})
15909 This allows users to define their own packages and make them visible to
15910 cuirass as in @command{guix build} command.
15912 @item @code{cuirass} (default: @code{cuirass})
15913 The Cuirass package to use.
15917 @node Power management Services
15918 @subsubsection Power management Services
15920 @cindex power management with TLP
15921 The @code{(gnu services pm)} module provides a Guix service definition
15922 for the Linux power management tool TLP.
15924 TLP enables various powersaving modes in userspace and kernel.
15925 Contrary to @code{upower-service}, it is not a passive,
15926 monitoring tool, as it will apply custom settings each time a new power
15927 source is detected. More information can be found at
15928 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
15930 @deffn {Scheme Variable} tlp-service-type
15931 The service type for the TLP tool. Its value should be a valid
15932 TLP configuration (see below). To use the default settings, simply
15935 (service tlp-service-type)
15939 By default TLP does not need much configuration but most TLP parameters
15940 can be tweaked using @code{tlp-configuration}.
15942 Each parameter definition is preceded by its type; for example,
15943 @samp{boolean foo} indicates that the @code{foo} parameter
15944 should be specified as a boolean. Types starting with
15945 @code{maybe-} denote parameters that won't show up in TLP config file
15946 when their value is @code{'disabled}.
15948 @c The following documentation was initially generated by
15949 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
15950 @c documentation is better, so we shouldn't hesitate to edit below as
15951 @c needed. However if the change you want to make to this documentation
15952 @c can be done in an automated way, it's probably easier to change
15953 @c (generate-documentation) than to make it below and have to deal with
15954 @c the churn as TLP updates.
15956 Available @code{tlp-configuration} fields are:
15958 @deftypevr {@code{tlp-configuration} parameter} package tlp
15963 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
15964 Set to true if you wish to enable TLP.
15966 Defaults to @samp{#t}.
15970 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
15971 Default mode when no power supply can be detected. Alternatives are AC
15974 Defaults to @samp{"AC"}.
15978 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
15979 Number of seconds Linux kernel has to wait after the disk goes idle,
15980 before syncing on AC.
15982 Defaults to @samp{0}.
15986 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
15987 Same as @code{disk-idle-ac} but on BAT mode.
15989 Defaults to @samp{2}.
15993 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
15994 Dirty pages flushing periodicity, expressed in seconds.
15996 Defaults to @samp{15}.
16000 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
16001 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
16003 Defaults to @samp{60}.
16007 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
16008 CPU frequency scaling governor on AC mode. With intel_pstate driver,
16009 alternatives are powersave and performance. With acpi-cpufreq driver,
16010 alternatives are ondemand, powersave, performance and conservative.
16012 Defaults to @samp{disabled}.
16016 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
16017 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
16019 Defaults to @samp{disabled}.
16023 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
16024 Set the min available frequency for the scaling governor on AC.
16026 Defaults to @samp{disabled}.
16030 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
16031 Set the max available frequency for the scaling governor on AC.
16033 Defaults to @samp{disabled}.
16037 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
16038 Set the min available frequency for the scaling governor on BAT.
16040 Defaults to @samp{disabled}.
16044 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
16045 Set the max available frequency for the scaling governor on BAT.
16047 Defaults to @samp{disabled}.
16051 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
16052 Limit the min P-state to control the power dissipation of the CPU, in AC
16053 mode. Values are stated as a percentage of the available performance.
16055 Defaults to @samp{disabled}.
16059 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
16060 Limit the max P-state to control the power dissipation of the CPU, in AC
16061 mode. Values are stated as a percentage of the available performance.
16063 Defaults to @samp{disabled}.
16067 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
16068 Same as @code{cpu-min-perf-on-ac} on BAT mode.
16070 Defaults to @samp{disabled}.
16074 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
16075 Same as @code{cpu-max-perf-on-ac} on BAT mode.
16077 Defaults to @samp{disabled}.
16081 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
16082 Enable CPU turbo boost feature on AC mode.
16084 Defaults to @samp{disabled}.
16088 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
16089 Same as @code{cpu-boost-on-ac?} on BAT mode.
16091 Defaults to @samp{disabled}.
16095 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
16096 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
16097 used under light load conditions.
16099 Defaults to @samp{#f}.
16103 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
16104 Same as @code{sched-powersave-on-ac?} but on BAT mode.
16106 Defaults to @samp{#t}.
16110 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
16111 Enable Linux kernel NMI watchdog.
16113 Defaults to @samp{#f}.
16117 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
16118 For Linux kernels with PHC patch applied, change CPU voltages. An
16119 example value would be @samp{"F:V F:V F:V F:V"}.
16121 Defaults to @samp{disabled}.
16125 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
16126 Set CPU performance versus energy saving policy on AC. Alternatives are
16127 performance, normal, powersave.
16129 Defaults to @samp{"performance"}.
16133 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
16134 Same as @code{energy-perf-policy-ac} but on BAT mode.
16136 Defaults to @samp{"powersave"}.
16140 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
16145 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
16146 Hard disk advanced power management level.
16150 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
16151 Same as @code{disk-apm-bat} but on BAT mode.
16155 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
16156 Hard disk spin down timeout. One value has to be specified for each
16157 declared hard disk.
16159 Defaults to @samp{disabled}.
16163 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
16164 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
16166 Defaults to @samp{disabled}.
16170 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
16171 Select IO scheduler for disk devices. One value has to be specified for
16172 each declared hard disk. Example alternatives are cfq, deadline and
16175 Defaults to @samp{disabled}.
16179 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
16180 SATA aggressive link power management (ALPM) level. Alternatives are
16181 min_power, medium_power, max_performance.
16183 Defaults to @samp{"max_performance"}.
16187 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
16188 Same as @code{sata-linkpwr-ac} but on BAT mode.
16190 Defaults to @samp{"min_power"}.
16194 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
16195 Exclude specified SATA host devices for link power management.
16197 Defaults to @samp{disabled}.
16201 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
16202 Enable Runtime Power Management for AHCI controller and disks on AC
16205 Defaults to @samp{disabled}.
16209 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
16210 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
16212 Defaults to @samp{disabled}.
16216 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
16217 Seconds of inactivity before disk is suspended.
16219 Defaults to @samp{15}.
16223 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
16224 PCI Express Active State Power Management level. Alternatives are
16225 default, performance, powersave.
16227 Defaults to @samp{"performance"}.
16231 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
16232 Same as @code{pcie-aspm-ac} but on BAT mode.
16234 Defaults to @samp{"powersave"}.
16238 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
16239 Radeon graphics clock speed level. Alternatives are low, mid, high,
16242 Defaults to @samp{"high"}.
16246 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
16247 Same as @code{radeon-power-ac} but on BAT mode.
16249 Defaults to @samp{"low"}.
16253 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
16254 Radeon dynamic power management method (DPM). Alternatives are battery,
16257 Defaults to @samp{"performance"}.
16261 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
16262 Same as @code{radeon-dpm-state-ac} but on BAT mode.
16264 Defaults to @samp{"battery"}.
16268 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
16269 Radeon DPM performance level. Alternatives are auto, low, high.
16271 Defaults to @samp{"auto"}.
16275 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
16276 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
16278 Defaults to @samp{"auto"}.
16282 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
16283 Wifi power saving mode.
16285 Defaults to @samp{#f}.
16289 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
16290 Same as @code{wifi-power-ac?} but on BAT mode.
16292 Defaults to @samp{#t}.
16296 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
16297 Disable wake on LAN.
16299 Defaults to @samp{#t}.
16303 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
16304 Timeout duration in seconds before activating audio power saving on
16305 Intel HDA and AC97 devices. A value of 0 disables power saving.
16307 Defaults to @samp{0}.
16311 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
16312 Same as @code{sound-powersave-ac} but on BAT mode.
16314 Defaults to @samp{1}.
16318 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
16319 Disable controller in powersaving mode on Intel HDA devices.
16321 Defaults to @samp{#t}.
16325 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
16326 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
16327 powered on again by releasing (and reinserting) the eject lever or by
16328 pressing the disc eject button on newer models.
16330 Defaults to @samp{#f}.
16334 @deftypevr {@code{tlp-configuration} parameter} string bay-device
16335 Name of the optical drive device to power off.
16337 Defaults to @samp{"sr0"}.
16341 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
16342 Runtime Power Management for PCI(e) bus devices. Alternatives are on
16345 Defaults to @samp{"on"}.
16349 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
16350 Same as @code{runtime-pm-ac} but on BAT mode.
16352 Defaults to @samp{"auto"}.
16356 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
16357 Runtime Power Management for all PCI(e) bus devices, except blacklisted
16360 Defaults to @samp{#t}.
16364 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
16365 Exclude specified PCI(e) device addresses from Runtime Power Management.
16367 Defaults to @samp{disabled}.
16371 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
16372 Exclude PCI(e) devices assigned to the specified drivers from Runtime
16377 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
16378 Enable USB autosuspend feature.
16380 Defaults to @samp{#t}.
16384 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
16385 Exclude specified devices from USB autosuspend.
16387 Defaults to @samp{disabled}.
16391 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
16392 Exclude WWAN devices from USB autosuspend.
16394 Defaults to @samp{#t}.
16398 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
16399 Include specified devices into USB autosuspend, even if they are already
16400 excluded by the driver or via @code{usb-blacklist-wwan?}.
16402 Defaults to @samp{disabled}.
16406 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
16407 Enable USB autosuspend before shutdown.
16409 Defaults to @samp{disabled}.
16413 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
16414 Restore radio device state (bluetooth, wifi, wwan) from previous
16415 shutdown on system startup.
16417 Defaults to @samp{#f}.
16422 The @code{(gnu services pm)} module provides an interface to
16423 thermald, a CPU frequency scaling service which helps prevent overheating.
16425 @defvr {Scheme Variable} thermald-service-type
16426 This is the service type for
16427 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
16428 Thermal Daemon, which is responsible for controlling the thermal state
16429 of processors and preventing overheating.
16432 @deftp {Data Type} thermald-configuration
16433 Data type representing the configuration of @code{thermald-service-type}.
16436 @item @code{ignore-cpuid-check?} (default: @code{#f})
16437 Ignore cpuid check for supported CPU models.
16439 @item @code{thermald} (default: @var{thermald})
16440 Package object of thermald.
16445 @node Audio Services
16446 @subsubsection Audio Services
16448 The @code{(gnu services audio)} module provides a service to start MPD
16449 (the Music Player Daemon).
16452 @subsubheading Music Player Daemon
16454 The Music Player Daemon (MPD) is a service that can play music while
16455 being controlled from the local machine or over the network by a variety
16458 The following example shows how one might run @code{mpd} as user
16459 @code{"bob"} on port @code{6666}. It uses pulseaudio for output.
16462 (service mpd-service-type
16468 @defvr {Scheme Variable} mpd-service-type
16469 The service type for @command{mpd}
16472 @deftp {Data Type} mpd-configuration
16473 Data type representing the configuration of @command{mpd}.
16476 @item @code{user} (default: @code{"mpd"})
16477 The user to run mpd as.
16479 @item @code{music-dir} (default: @code{"~/Music"})
16480 The directory to scan for music files.
16482 @item @code{playlist-dir} (default: @code{"~/.mpd/playlists"})
16483 The directory to store playlists.
16485 @item @code{port} (default: @code{"6600"})
16486 The port to run mpd on.
16488 @item @code{address} (default: @code{"any"})
16489 The address that mpd will bind to. To use a Unix domain socket,
16490 an absolute path can be specified here.
16495 @node Virtualization Services
16496 @subsubsection Virtualization services
16497 The @code{(gnu services virtualization)} module provides services for
16498 the libvirt and virtlog daemons.
16500 @subsubheading Libvirt daemon
16501 @code{libvirtd} is the server side daemon component of the libvirt
16502 virtualization management system. This daemon runs on host servers
16503 and performs required management tasks for virtualized guests.
16505 @deffn {Scheme Variable} libvirt-service-type
16506 This is the type of the @uref{https://libvirt.org, libvirt daemon}.
16507 Its value must be a @code{libvirt-configuration}.
16510 (service libvirt-service-type
16511 (libvirt-configuration
16512 (unix-sock-group "libvirt")
16513 (tls-port "16555")))
16517 @c Auto-generated with (generate-libvirt-documentation)
16518 Available @code{libvirt-configuration} fields are:
16520 @deftypevr {@code{libvirt-configuration} parameter} package libvirt
16525 @deftypevr {@code{libvirt-configuration} parameter} boolean listen-tls?
16526 Flag listening for secure TLS connections on the public TCP/IP port.
16527 must set @code{listen} for this to have any effect.
16529 It is necessary to setup a CA and issue server certificates before using
16532 Defaults to @samp{#t}.
16536 @deftypevr {@code{libvirt-configuration} parameter} boolean listen-tcp?
16537 Listen for unencrypted TCP connections on the public TCP/IP port. must
16538 set @code{listen} for this to have any effect.
16540 Using the TCP socket requires SASL authentication by default. Only SASL
16541 mechanisms which support data encryption are allowed. This is
16542 DIGEST_MD5 and GSSAPI (Kerberos5)
16544 Defaults to @samp{#f}.
16548 @deftypevr {@code{libvirt-configuration} parameter} string tls-port
16549 Port for accepting secure TLS connections This can be a port number, or
16552 Defaults to @samp{"16514"}.
16556 @deftypevr {@code{libvirt-configuration} parameter} string tcp-port
16557 Port for accepting insecure TCP connections This can be a port number,
16560 Defaults to @samp{"16509"}.
16564 @deftypevr {@code{libvirt-configuration} parameter} string listen-addr
16565 IP address or hostname used for client connections.
16567 Defaults to @samp{"0.0.0.0"}.
16571 @deftypevr {@code{libvirt-configuration} parameter} boolean mdns-adv?
16572 Flag toggling mDNS advertisement of the libvirt service.
16574 Alternatively can disable for all services on a host by stopping the
16577 Defaults to @samp{#f}.
16581 @deftypevr {@code{libvirt-configuration} parameter} string mdns-name
16582 Default mDNS advertisement name. This must be unique on the immediate
16585 Defaults to @samp{"Virtualization Host <hostname>"}.
16589 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-group
16590 UNIX domain socket group ownership. This can be used to allow a
16591 'trusted' set of users access to management capabilities without
16594 Defaults to @samp{"root"}.
16598 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-ro-perms
16599 UNIX socket permissions for the R/O socket. This is used for monitoring
16602 Defaults to @samp{"0777"}.
16606 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-rw-perms
16607 UNIX socket permissions for the R/W socket. Default allows only root.
16608 If PolicyKit is enabled on the socket, the default will change to allow
16609 everyone (eg, 0777)
16611 Defaults to @samp{"0770"}.
16615 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-admin-perms
16616 UNIX socket permissions for the admin socket. Default allows only owner
16617 (root), do not change it unless you are sure to whom you are exposing
16620 Defaults to @samp{"0777"}.
16624 @deftypevr {@code{libvirt-configuration} parameter} string unix-sock-dir
16625 The directory in which sockets will be found/created.
16627 Defaults to @samp{"/var/run/libvirt"}.
16631 @deftypevr {@code{libvirt-configuration} parameter} string auth-unix-ro
16632 Authentication scheme for UNIX read-only sockets. By default socket
16633 permissions allow anyone to connect
16635 Defaults to @samp{"polkit"}.
16639 @deftypevr {@code{libvirt-configuration} parameter} string auth-unix-rw
16640 Authentication scheme for UNIX read-write sockets. By default socket
16641 permissions only allow root. If PolicyKit support was compiled into
16642 libvirt, the default will be to use 'polkit' auth.
16644 Defaults to @samp{"polkit"}.
16648 @deftypevr {@code{libvirt-configuration} parameter} string auth-tcp
16649 Authentication scheme for TCP sockets. If you don't enable SASL, then
16650 all TCP traffic is cleartext. Don't do this outside of a dev/test
16653 Defaults to @samp{"sasl"}.
16657 @deftypevr {@code{libvirt-configuration} parameter} string auth-tls
16658 Authentication scheme for TLS sockets. TLS sockets already have
16659 encryption provided by the TLS layer, and limited authentication is done
16662 It is possible to make use of any SASL authentication mechanism as well,
16663 by using 'sasl' for this option
16665 Defaults to @samp{"none"}.
16669 @deftypevr {@code{libvirt-configuration} parameter} optional-list access-drivers
16670 API access control scheme.
16672 By default an authenticated user is allowed access to all APIs. Access
16673 drivers can place restrictions on this.
16675 Defaults to @samp{()}.
16679 @deftypevr {@code{libvirt-configuration} parameter} string key-file
16680 Server key file path. If set to an empty string, then no private key is
16683 Defaults to @samp{""}.
16687 @deftypevr {@code{libvirt-configuration} parameter} string cert-file
16688 Server key file path. If set to an empty string, then no certificate is
16691 Defaults to @samp{""}.
16695 @deftypevr {@code{libvirt-configuration} parameter} string ca-file
16696 Server key file path. If set to an empty string, then no CA certificate
16699 Defaults to @samp{""}.
16703 @deftypevr {@code{libvirt-configuration} parameter} string crl-file
16704 Certificate revocation list path. If set to an empty string, then no
16707 Defaults to @samp{""}.
16711 @deftypevr {@code{libvirt-configuration} parameter} boolean tls-no-sanity-cert
16712 Disable verification of our own server certificates.
16714 When libvirtd starts it performs some sanity checks against its own
16717 Defaults to @samp{#f}.
16721 @deftypevr {@code{libvirt-configuration} parameter} boolean tls-no-verify-cert
16722 Disable verification of client certificates.
16724 Client certificate verification is the primary authentication mechanism.
16725 Any client which does not present a certificate signed by the CA will be
16728 Defaults to @samp{#f}.
16732 @deftypevr {@code{libvirt-configuration} parameter} optional-list tls-allowed-dn-list
16733 Whitelist of allowed x509 Distinguished Name.
16735 Defaults to @samp{()}.
16739 @deftypevr {@code{libvirt-configuration} parameter} optional-list sasl-allowed-usernames
16740 Whitelist of allowed SASL usernames. The format for username depends on
16741 the SASL authentication mechanism.
16743 Defaults to @samp{()}.
16747 @deftypevr {@code{libvirt-configuration} parameter} string tls-priority
16748 Override the compile time default TLS priority string. The default is
16749 usually "NORMAL" unless overridden at build time. Only set this is it
16750 is desired for libvirt to deviate from the global default settings.
16752 Defaults to @samp{"NORMAL"}.
16756 @deftypevr {@code{libvirt-configuration} parameter} integer max-clients
16757 Maximum number of concurrent client connections to allow over all
16760 Defaults to @samp{5000}.
16764 @deftypevr {@code{libvirt-configuration} parameter} integer max-queued-clients
16765 Maximum length of queue of connections waiting to be accepted by the
16766 daemon. Note, that some protocols supporting retransmission may obey
16767 this so that a later reattempt at connection succeeds.
16769 Defaults to @samp{1000}.
16773 @deftypevr {@code{libvirt-configuration} parameter} integer max-anonymous-clients
16774 Maximum length of queue of accepted but not yet authenticated clients.
16775 Set this to zero to turn this feature off
16777 Defaults to @samp{20}.
16781 @deftypevr {@code{libvirt-configuration} parameter} integer min-workers
16782 Number of workers to start up initially.
16784 Defaults to @samp{5}.
16788 @deftypevr {@code{libvirt-configuration} parameter} integer max-workers
16789 Maximum number of worker threads.
16791 If the number of active clients exceeds @code{min-workers}, then more
16792 threads are spawned, up to max_workers limit. Typically you'd want
16793 max_workers to equal maximum number of clients allowed.
16795 Defaults to @samp{20}.
16799 @deftypevr {@code{libvirt-configuration} parameter} integer prio-workers
16800 Number of priority workers. If all workers from above pool are stuck,
16801 some calls marked as high priority (notably domainDestroy) can be
16802 executed in this pool.
16804 Defaults to @samp{5}.
16808 @deftypevr {@code{libvirt-configuration} parameter} integer max-requests
16809 Total global limit on concurrent RPC calls.
16811 Defaults to @samp{20}.
16815 @deftypevr {@code{libvirt-configuration} parameter} integer max-client-requests
16816 Limit on concurrent requests from a single client connection. To avoid
16817 one client monopolizing the server this should be a small fraction of
16818 the global max_requests and max_workers parameter.
16820 Defaults to @samp{5}.
16824 @deftypevr {@code{libvirt-configuration} parameter} integer admin-min-workers
16825 Same as @code{min-workers} but for the admin interface.
16827 Defaults to @samp{1}.
16831 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-workers
16832 Same as @code{max-workers} but for the admin interface.
16834 Defaults to @samp{5}.
16838 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-clients
16839 Same as @code{max-clients} but for the admin interface.
16841 Defaults to @samp{5}.
16845 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-queued-clients
16846 Same as @code{max-queued-clients} but for the admin interface.
16848 Defaults to @samp{5}.
16852 @deftypevr {@code{libvirt-configuration} parameter} integer admin-max-client-requests
16853 Same as @code{max-client-requests} but for the admin interface.
16855 Defaults to @samp{5}.
16859 @deftypevr {@code{libvirt-configuration} parameter} integer log-level
16860 Logging level. 4 errors, 3 warnings, 2 information, 1 debug.
16862 Defaults to @samp{3}.
16866 @deftypevr {@code{libvirt-configuration} parameter} string log-filters
16869 A filter allows to select a different logging level for a given category
16870 of logs The format for a filter is one of:
16881 where @code{name} is a string which is matched against the category
16882 given in the @code{VIR_LOG_INIT()} at the top of each libvirt source
16883 file, e.g., "remote", "qemu", or "util.json" (the name in the filter can
16884 be a substring of the full category name, in order to match multiple
16885 similar categories), the optional "+" prefix tells libvirt to log stack
16886 trace for each message matching name, and @code{x} is the minimal level
16887 where matching messages should be logged:
16904 Multiple filters can be defined in a single filters statement, they just
16905 need to be separated by spaces.
16907 Defaults to @samp{"3:remote 4:event"}.
16911 @deftypevr {@code{libvirt-configuration} parameter} string log-outputs
16914 An output is one of the places to save logging information The format
16915 for an output can be:
16919 output goes to stderr
16921 @item x:syslog:name
16922 use syslog for the output and use the given name as the ident
16924 @item x:file:file_path
16925 output to a file, with the given filepath
16928 output to journald logging system
16932 In all case the x prefix is the minimal level, acting as a filter
16949 Multiple outputs can be defined, they just need to be separated by
16952 Defaults to @samp{"3:stderr"}.
16956 @deftypevr {@code{libvirt-configuration} parameter} integer audit-level
16957 Allows usage of the auditing subsystem to be altered
16961 0: disable all auditing
16964 1: enable auditing, only if enabled on host
16967 2: enable auditing, and exit if disabled on host.
16971 Defaults to @samp{1}.
16975 @deftypevr {@code{libvirt-configuration} parameter} boolean audit-logging
16976 Send audit messages via libvirt logging infrastructure.
16978 Defaults to @samp{#f}.
16982 @deftypevr {@code{libvirt-configuration} parameter} optional-string host-uuid
16983 Host UUID. UUID must not have all digits be the same.
16985 Defaults to @samp{""}.
16989 @deftypevr {@code{libvirt-configuration} parameter} string host-uuid-source
16990 Source to read host UUID.
16994 @code{smbios}: fetch the UUID from @code{dmidecode -s system-uuid}
16997 @code{machine-id}: fetch the UUID from @code{/etc/machine-id}
17001 If @code{dmidecode} does not provide a valid UUID a temporary UUID will
17004 Defaults to @samp{"smbios"}.
17008 @deftypevr {@code{libvirt-configuration} parameter} integer keepalive-interval
17009 A keepalive message is sent to a client after @code{keepalive_interval}
17010 seconds of inactivity to check if the client is still responding. If
17011 set to -1, libvirtd will never send keepalive requests; however clients
17012 can still send them and the daemon will send responses.
17014 Defaults to @samp{5}.
17018 @deftypevr {@code{libvirt-configuration} parameter} integer keepalive-count
17019 Maximum number of keepalive messages that are allowed to be sent to the
17020 client without getting any response before the connection is considered
17023 In other words, the connection is automatically closed approximately
17024 after @code{keepalive_interval * (keepalive_count + 1)} seconds since
17025 the last message received from the client. When @code{keepalive-count}
17026 is set to 0, connections will be automatically closed after
17027 @code{keepalive-interval} seconds of inactivity without sending any
17028 keepalive messages.
17030 Defaults to @samp{5}.
17034 @deftypevr {@code{libvirt-configuration} parameter} integer admin-keepalive-interval
17035 Same as above but for admin interface.
17037 Defaults to @samp{5}.
17041 @deftypevr {@code{libvirt-configuration} parameter} integer admin-keepalive-count
17042 Same as above but for admin interface.
17044 Defaults to @samp{5}.
17048 @deftypevr {@code{libvirt-configuration} parameter} integer ovs-timeout
17049 Timeout for Open vSwitch calls.
17051 The @code{ovs-vsctl} utility is used for the configuration and its
17052 timeout option is set by default to 5 seconds to avoid potential
17053 infinite waits blocking libvirt.
17055 Defaults to @samp{5}.
17059 @c %end of autogenerated docs
17061 @subsubheading Virtlog daemon
17062 The virtlogd service is a server side daemon component of libvirt that is
17063 used to manage logs from virtual machine consoles.
17065 This daemon is not used directly by libvirt client applications, rather it
17066 is called on their behalf by @code{libvirtd}. By maintaining the logs in a
17067 standalone daemon, the main @code{libvirtd} daemon can be restarted without
17068 risk of losing logs. The @code{virtlogd} daemon has the ability to re-exec()
17069 itself upon receiving @code{SIGUSR1}, to allow live upgrades without downtime.
17071 @deffn {Scheme Variable} virtlog-service-type
17072 This is the type of the virtlog daemon.
17073 Its value must be a @code{virtlog-configuration}.
17076 (service virtlog-service-type
17077 (virtlog-configuration
17078 (max-clients 1000)))
17082 @deftypevr {@code{virtlog-configuration} parameter} integer log-level
17083 Logging level. 4 errors, 3 warnings, 2 information, 1 debug.
17085 Defaults to @samp{3}.
17089 @deftypevr {@code{virtlog-configuration} parameter} string log-filters
17092 A filter allows to select a different logging level for a given category
17093 of logs The format for a filter is one of:
17104 where @code{name} is a string which is matched against the category
17105 given in the @code{VIR_LOG_INIT()} at the top of each libvirt source
17106 file, e.g., "remote", "qemu", or "util.json" (the name in the filter can
17107 be a substring of the full category name, in order to match multiple
17108 similar categories), the optional "+" prefix tells libvirt to log stack
17109 trace for each message matching name, and @code{x} is the minimal level
17110 where matching messages should be logged:
17127 Multiple filters can be defined in a single filters statement, they just
17128 need to be separated by spaces.
17130 Defaults to @samp{"3:remote 4:event"}.
17134 @deftypevr {@code{virtlog-configuration} parameter} string log-outputs
17137 An output is one of the places to save logging information The format
17138 for an output can be:
17142 output goes to stderr
17144 @item x:syslog:name
17145 use syslog for the output and use the given name as the ident
17147 @item x:file:file_path
17148 output to a file, with the given filepath
17151 output to journald logging system
17155 In all case the x prefix is the minimal level, acting as a filter
17172 Multiple outputs can be defined, they just need to be separated by
17175 Defaults to @samp{"3:stderr"}.
17179 @deftypevr {@code{virtlog-configuration} parameter} integer max-clients
17180 Maximum number of concurrent client connections to allow over all
17183 Defaults to @samp{1024}.
17187 @deftypevr {@code{virtlog-configuration} parameter} integer max-size
17188 Maximum file size before rolling over.
17190 Defaults to @samp{2MB}
17194 @deftypevr {@code{virtlog-configuration} parameter} integer max-backups
17195 Maximum number of backup files to keep.
17197 Defaults to @samp{3}
17202 @node Miscellaneous Services
17203 @subsubsection Miscellaneous Services
17206 @subsubheading System Control Service
17208 The @code{(gnu services sysctl)} provides a service to configure kernel
17209 parameters at boot.
17211 @defvr {Scheme Variable} sysctl-service-type
17212 The service type for @command{sysctl}, which modifies kernel parameters
17213 under @file{/proc/sys/}. To enable IPv4 forwarding, it can be
17217 (service sysctl-service-type
17218 (sysctl-configuration
17219 (settings '(("net.ipv4.ip_forward" . "1")))))
17223 @deftp {Data Type} sysctl-configuration
17224 The data type representing the configuration of @command{sysctl}.
17227 @item @code{sysctl} (default: @code{(file-append procps "/sbin/sysctl"})
17228 The @command{sysctl} executable to use.
17230 @item @code{settings} (default: @code{'()})
17231 An association list specifies kernel parameters and their values.
17236 @subsubheading Lirc Service
17238 The @code{(gnu services lirc)} module provides the following service.
17240 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
17241 [#:device #f] [#:driver #f] [#:config-file #f] @
17242 [#:extra-options '()]
17243 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
17244 decodes infrared signals from remote controls.
17246 Optionally, @var{device}, @var{driver} and @var{config-file}
17247 (configuration file name) may be specified. See @command{lircd} manual
17250 Finally, @var{extra-options} is a list of additional command-line options
17251 passed to @command{lircd}.
17255 @subsubheading Spice Service
17257 The @code{(gnu services spice)} module provides the following service.
17259 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
17260 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
17261 that enables sharing the clipboard with a vm and setting the guest display
17262 resolution when the graphical console window resizes.
17265 @subsubsection Dictionary Services
17267 The @code{(gnu services dict)} module provides the following service:
17269 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
17270 Return a service that runs the @command{dicod} daemon, an implementation
17271 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
17273 The optional @var{config} argument specifies the configuration for
17274 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
17275 default it serves the GNU Collaborative International Dictonary of English.
17277 You can add @command{open localhost} to your @file{~/.dico} file to make
17278 @code{localhost} the default server for @command{dico} client
17279 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
17282 @deftp {Data Type} dicod-configuration
17283 Data type representing the configuration of dicod.
17286 @item @code{dico} (default: @var{dico})
17287 Package object of the GNU Dico dictionary server.
17289 @item @code{interfaces} (default: @var{'("localhost")})
17290 This is the list of IP addresses and ports and possibly socket file
17291 names to listen to (@pxref{Server Settings, @code{listen} directive,,
17292 dico, GNU Dico Manual}).
17294 @item @code{handlers} (default: @var{'()})
17295 List of @code{<dicod-handler>} objects denoting handlers (module instances).
17297 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
17298 List of @code{<dicod-database>} objects denoting dictionaries to be served.
17302 @deftp {Data Type} dicod-handler
17303 Data type representing a dictionary handler (module instance).
17307 Name of the handler (module instance).
17309 @item @code{module} (default: @var{#f})
17310 Name of the dicod module of the handler (instance). If it is @code{#f},
17311 the module has the same name as the handler.
17312 (@pxref{Modules,,, dico, GNU Dico Manual}).
17314 @item @code{options}
17315 List of strings or gexps representing the arguments for the module handler
17319 @deftp {Data Type} dicod-database
17320 Data type representing a dictionary database.
17324 Name of the database, will be used in DICT commands.
17326 @item @code{handler}
17327 Name of the dicod handler (module instance) used by this database
17328 (@pxref{Handlers,,, dico, GNU Dico Manual}).
17330 @item @code{complex?} (default: @var{#f})
17331 Whether the database configuration complex. The complex configuration
17332 will need a corresponding @code{<dicod-handler>} object, otherwise not.
17334 @item @code{options}
17335 List of strings or gexps representing the arguments for the database
17336 (@pxref{Databases,,, dico, GNU Dico Manual}).
17340 @defvr {Scheme Variable} %dicod-database:gcide
17341 A @code{<dicod-database>} object serving the GNU Collaborative International
17342 Dictionary of English using the @code{gcide} package.
17345 The following is an example @code{dicod-service} configuration.
17348 (dicod-service #:config
17349 (dicod-configuration
17350 (handlers (list (dicod-handler
17354 (list #~(string-append "dbdir=" #$wordnet))))))
17355 (databases (list (dicod-database
17358 (handler "wordnet")
17359 (options '("database=wn")))
17360 %dicod-database:gcide))))
17363 @subsubsection Version Control
17365 The @code{(gnu services version-control)} module provides the following services:
17367 @subsubheading Git daemon service
17369 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
17371 Return a service that runs @command{git daemon}, a simple TCP server to
17372 expose repositories over the Git protocol for anonymous access.
17374 The optional @var{config} argument should be a
17375 @code{<git-daemon-configuration>} object, by default it allows read-only
17376 access to exported@footnote{By creating the magic file
17377 "git-daemon-export-ok" in the repository directory.} repositories under
17382 @deftp {Data Type} git-daemon-configuration
17383 Data type representing the configuration for @code{git-daemon-service}.
17386 @item @code{package} (default: @var{git})
17387 Package object of the Git distributed version control system.
17389 @item @code{export-all?} (default: @var{#f})
17390 Whether to allow access for all Git repositories, even if they do not
17391 have the @file{git-daemon-export-ok} file.
17393 @item @code{base-path} (default: @file{/srv/git})
17394 Whether to remap all the path requests as relative to the given path.
17395 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
17396 then if you later try to pull @code{git://example.com/hello.git}, git
17397 daemon will interpret the path as @code{/srv/git/hello.git}.
17399 @item @code{user-path} (default: @var{#f})
17400 Whether to allow @code{~user} notation to be used in requests. When
17401 specified with empty string, requests to @code{git://host/~alice/foo} is
17402 taken as a request to access @code{foo} repository in the home directory
17403 of user @code{alice}. If @var{(user-path "path")} is specified, the
17404 same request is taken as a request to access @code{path/foo} repository
17405 in the home directory of user @code{alice}.
17407 @item @code{listen} (default: @var{'()})
17408 Whether to listen on specific IP addresses or hostnames, defaults to
17411 @item @code{port} (default: @var{#f})
17412 Whether to listen on an alternative port, which defaults to 9418.
17414 @item @code{whitelist} (default: @var{'()})
17415 If not empty, only allow access to this list of directories.
17417 @item @code{extra-options} (default: @var{'()})
17418 Extra options will be passed to @code{git daemon}, please run
17419 @command{man git-daemon} for more information.
17424 @subsubheading Cgit Service
17426 @cindex Cgit service
17427 @cindex Git, web interface
17428 @uref{https://git.zx2c4.com/cgit/, Cgit} is a web frontend for Git
17429 repositories written in C.
17431 The following example will configure the service with default values.
17432 By default, Cgit can be accessed on port 80 (@code{http://localhost:80}).
17435 (service nginx-service-type)
17436 (service fcgiwrap-service-type)
17437 (service cgit-service-type)
17440 @deftp {Data Type} cgit-configuration
17441 Data type representing the configuration of Cgit.
17442 This type has the following parameters:
17445 @item @code{config-file} (default: @code{(cgit-configuration-file)})
17446 The configuration file to use for Cgit. This can be set to a
17447 @dfn{cgit-configuration-file} record value, or any gexp
17448 (@pxref{G-Expressions}).
17450 For example, to instead use a local file, the @code{local-file} function
17454 (service cgit-service-type
17455 (cgit-configuration
17456 (config-file (local-file "./my-cgitrc.conf"))))
17459 @item @code{package} (default: @code{cgit})
17460 The Cgit package to use.
17465 @deftp {Data Type} cgit-configuration-file
17466 Data type representing the configuration options for Cgit.
17467 This type has the following parameters:
17470 @item @code{css} (default: @code{"/share/cgit/cgit.css"})
17471 URL which specifies the css document to include in all Cgit pages.
17473 @item @code{logo} (default: @code{"/share/cgit/cgit.png"})
17474 URL which specifies the source of an image which will be used as a logo
17477 @item @code{virtual-root} (default: @code{"/"})
17478 URL which, if specified, will be used as root for all Cgit links.
17480 @item @code{repository-directory} (default: @code{"/srv/git"})
17481 Name of the directory to scan for repositories.
17483 @item @code{robots} (default: @code{(list "noindex" "nofollow")})
17484 Text used as content for the ``robots'' meta-tag.
17489 @node Setuid Programs
17490 @subsection Setuid Programs
17492 @cindex setuid programs
17493 Some programs need to run with ``root'' privileges, even when they are
17494 launched by unprivileged users. A notorious example is the
17495 @command{passwd} program, which users can run to change their
17496 password, and which needs to access the @file{/etc/passwd} and
17497 @file{/etc/shadow} files---something normally restricted to root, for
17498 obvious security reasons. To address that, these executables are
17499 @dfn{setuid-root}, meaning that they always run with root privileges
17500 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
17501 for more info about the setuid mechanism.)
17503 The store itself @emph{cannot} contain setuid programs: that would be a
17504 security issue since any user on the system can write derivations that
17505 populate the store (@pxref{The Store}). Thus, a different mechanism is
17506 used: instead of changing the setuid bit directly on files that are in
17507 the store, we let the system administrator @emph{declare} which programs
17508 should be setuid root.
17510 The @code{setuid-programs} field of an @code{operating-system}
17511 declaration contains a list of G-expressions denoting the names of
17512 programs to be setuid-root (@pxref{Using the Configuration System}).
17513 For instance, the @command{passwd} program, which is part of the Shadow
17514 package, can be designated by this G-expression (@pxref{G-Expressions}):
17517 #~(string-append #$shadow "/bin/passwd")
17520 A default set of setuid programs is defined by the
17521 @code{%setuid-programs} variable of the @code{(gnu system)} module.
17523 @defvr {Scheme Variable} %setuid-programs
17524 A list of G-expressions denoting common programs that are setuid-root.
17526 The list includes commands such as @command{passwd}, @command{ping},
17527 @command{su}, and @command{sudo}.
17530 Under the hood, the actual setuid programs are created in the
17531 @file{/run/setuid-programs} directory at system activation time. The
17532 files in this directory refer to the ``real'' binaries, which are in the
17535 @node X.509 Certificates
17536 @subsection X.509 Certificates
17538 @cindex HTTPS, certificates
17539 @cindex X.509 certificates
17541 Web servers available over HTTPS (that is, HTTP over the transport-layer
17542 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
17543 that the client can then use to @emph{authenticate} the server. To do
17544 that, clients verify that the server's certificate is signed by a
17545 so-called @dfn{certificate authority} (CA). But to verify the CA's
17546 signature, clients must have first acquired the CA's certificate.
17548 Web browsers such as GNU@tie{}IceCat include their own set of CA
17549 certificates, such that they are able to verify CA signatures
17552 However, most other programs that can talk HTTPS---@command{wget},
17553 @command{git}, @command{w3m}, etc.---need to be told where CA
17554 certificates can be found.
17556 @cindex @code{nss-certs}
17557 In GuixSD, this is done by adding a package that provides certificates
17558 to the @code{packages} field of the @code{operating-system} declaration
17559 (@pxref{operating-system Reference}). GuixSD includes one such package,
17560 @code{nss-certs}, which is a set of CA certificates provided as part of
17561 Mozilla's Network Security Services.
17563 Note that it is @emph{not} part of @var{%base-packages}, so you need to
17564 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
17565 most applications and libraries look for certificates by default, points
17566 to the certificates installed globally.
17568 Unprivileged users, including users of Guix on a foreign distro,
17569 can also install their own certificate package in
17570 their profile. A number of environment variables need to be defined so
17571 that applications and libraries know where to find them. Namely, the
17572 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
17573 variables. Some applications add their own environment variables; for
17574 instance, the Git version control system honors the certificate bundle
17575 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
17576 would typically run something like:
17579 $ guix package -i nss-certs
17580 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
17581 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
17582 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
17585 As another example, R requires the @code{CURL_CA_BUNDLE} environment
17586 variable to point to a certificate bundle, so you would have to run
17587 something like this:
17590 $ guix package -i nss-certs
17591 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
17594 For other applications you may want to look up the required environment
17595 variable in the relevant documentation.
17598 @node Name Service Switch
17599 @subsection Name Service Switch
17601 @cindex name service switch
17603 The @code{(gnu system nss)} module provides bindings to the
17604 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
17605 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
17606 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
17607 extended with new ``name'' lookup methods for system databases, which
17608 includes host names, service names, user accounts, and more (@pxref{Name
17609 Service Switch, System Databases and Name Service Switch,, libc, The GNU
17610 C Library Reference Manual}).
17612 The NSS configuration specifies, for each system database, which lookup
17613 method is to be used, and how the various methods are chained
17614 together---for instance, under which circumstances NSS should try the
17615 next method in the list. The NSS configuration is given in the
17616 @code{name-service-switch} field of @code{operating-system} declarations
17617 (@pxref{operating-system Reference, @code{name-service-switch}}).
17620 @cindex .local, host name lookup
17621 As an example, the declaration below configures the NSS to use the
17622 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
17623 back-end}, which supports host name lookups over multicast DNS (mDNS)
17624 for host names ending in @code{.local}:
17627 (name-service-switch
17628 (hosts (list %files ;first, check /etc/hosts
17630 ;; If the above did not succeed, try
17631 ;; with 'mdns_minimal'.
17633 (name "mdns_minimal")
17635 ;; 'mdns_minimal' is authoritative for
17636 ;; '.local'. When it returns "not found",
17637 ;; no need to try the next methods.
17638 (reaction (lookup-specification
17639 (not-found => return))))
17641 ;; Then fall back to DNS.
17645 ;; Finally, try with the "full" 'mdns'.
17650 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
17651 contains this configuration, so you will not have to type it if all you
17652 want is to have @code{.local} host lookup working.
17654 Note that, in this case, in addition to setting the
17655 @code{name-service-switch} of the @code{operating-system} declaration,
17656 you also need to use @code{avahi-service} (@pxref{Networking Services,
17657 @code{avahi-service}}), or @var{%desktop-services}, which includes it
17658 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
17659 to the name service cache daemon (@pxref{Base Services,
17660 @code{nscd-service}}).
17662 For convenience, the following variables provide typical NSS
17665 @defvr {Scheme Variable} %default-nss
17666 This is the default name service switch configuration, a
17667 @code{name-service-switch} object.
17670 @defvr {Scheme Variable} %mdns-host-lookup-nss
17671 This is the name service switch configuration with support for host name
17672 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
17675 The reference for name service switch configuration is given below. It
17676 is a direct mapping of the configuration file format of the C library , so
17677 please refer to the C library manual for more information (@pxref{NSS
17678 Configuration File,,, libc, The GNU C Library Reference Manual}).
17679 Compared to the configuration file format of libc NSS, it has the advantage
17680 not only of adding this warm parenthetic feel that we like, but also
17681 static checks: you will know about syntax errors and typos as soon as you
17682 run @command{guix system}.
17684 @deftp {Data Type} name-service-switch
17686 This is the data type representation the configuration of libc's name
17687 service switch (NSS). Each field below represents one of the supported
17704 The system databases handled by the NSS. Each of these fields must be a
17705 list of @code{<name-service>} objects (see below).
17709 @deftp {Data Type} name-service
17711 This is the data type representing an actual name service and the
17712 associated lookup action.
17716 A string denoting the name service (@pxref{Services in the NSS
17717 configuration,,, libc, The GNU C Library Reference Manual}).
17719 Note that name services listed here must be visible to nscd. This is
17720 achieved by passing the @code{#:name-services} argument to
17721 @code{nscd-service} the list of packages providing the needed name
17722 services (@pxref{Base Services, @code{nscd-service}}).
17725 An action specified using the @code{lookup-specification} macro
17726 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
17727 Reference Manual}). For example:
17730 (lookup-specification (unavailable => continue)
17731 (success => return))
17736 @node Initial RAM Disk
17737 @subsection Initial RAM Disk
17740 @cindex initial RAM disk
17741 For bootstrapping purposes, the Linux-Libre kernel is passed an
17742 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
17743 root file system as well as an initialization script. The latter is
17744 responsible for mounting the real root file system, and for loading any
17745 kernel modules that may be needed to achieve that.
17747 The @code{initrd} field of an @code{operating-system} declaration allows
17748 you to specify which initrd you would like to use. The @code{(gnu
17749 system linux-initrd)} module provides three ways to build an initrd: the
17750 high-level @code{base-initrd} procedure and the low-level
17751 @code{raw-initrd} and @code{expression->initrd} procedures.
17753 The @code{base-initrd} procedure is intended to cover most common uses.
17754 For example, if you want to add a bunch of kernel modules to be loaded
17755 at boot time, you can define the @code{initrd} field of the operating
17756 system declaration like this:
17759 (initrd (lambda (file-systems . rest)
17760 ;; Create a standard initrd that has modules "foo.ko"
17761 ;; and "bar.ko", as well as their dependencies, in
17762 ;; addition to the modules available by default.
17763 (apply base-initrd file-systems
17764 #:extra-modules '("foo" "bar")
17768 The @code{base-initrd} procedure also handles common use cases that
17769 involves using the system as a QEMU guest, or as a ``live'' system with
17770 volatile root file system.
17772 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
17773 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
17774 such as trying to guess which kernel modules and packages should be included
17775 to the initrd. An example use of @code{raw-initrd} is when a user has
17776 a custom Linux kernel configuration and default kernel modules included by
17777 @code{base-initrd} are not available.
17779 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
17780 honors several options passed on the Linux kernel command line
17781 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
17782 @code{-append} option of QEMU), notably:
17785 @item --load=@var{boot}
17786 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
17787 program, once it has mounted the root file system.
17789 GuixSD uses this option to yield control to a boot program that runs the
17790 service activation programs and then spawns the GNU@tie{}Shepherd, the
17791 initialization system.
17793 @item --root=@var{root}
17794 Mount @var{root} as the root file system. @var{root} can be a
17795 device name like @code{/dev/sda1}, a partition label, or a partition
17798 @item --system=@var{system}
17799 Have @file{/run/booted-system} and @file{/run/current-system} point to
17802 @item modprobe.blacklist=@var{modules}@dots{}
17803 @cindex module, black-listing
17804 @cindex black list, of kernel modules
17805 Instruct the initial RAM disk as well as the @command{modprobe} command
17806 (from the kmod package) to refuse to load @var{modules}. @var{modules}
17807 must be a comma-separated list of module names---e.g.,
17808 @code{usbkbd,9pnet}.
17811 Start a read-eval-print loop (REPL) from the initial RAM disk before it
17812 tries to load kernel modules and to mount the root file system. Our
17813 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
17814 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
17815 Manual}, for more information on Guile's REPL.
17819 Now that you know all the features that initial RAM disks produced by
17820 @code{base-initrd} and @code{raw-initrd} provide,
17821 here is how to use it and customize it further.
17824 @cindex initial RAM disk
17825 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
17826 [#:linux-modules '()] [#:mapped-devices '()] @
17827 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
17828 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
17829 a list of file systems to be mounted by the initrd, possibly in addition to
17830 the root file system specified on the kernel command line via @code{--root}.
17831 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
17832 @var{mapped-devices} is a list of device mappings to realize before
17833 @var{file-systems} are mounted (@pxref{Mapped Devices}).
17834 @var{helper-packages} is a list of packages to be copied in the initrd. It may
17835 include @code{e2fsck/static} or other packages needed by the initrd to check
17838 When @var{qemu-networking?} is true, set up networking with the standard QEMU
17839 parameters. When @var{virtio?} is true, load additional modules so that the
17840 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
17842 When @var{volatile-root?} is true, the root file system is writable but any changes
17846 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
17847 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
17848 [#:virtio? #t] [#:extra-modules '()]
17849 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
17850 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
17851 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
17852 also behaves as in @code{raw-initrd}.
17854 When @var{virtio?} is true, load additional modules so that the
17855 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
17857 The initrd is automatically populated with all the kernel modules necessary
17858 for @var{file-systems} and for the given options. However, additional kernel
17859 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
17860 loaded at boot time in the order in which they appear.
17863 Needless to say, the initrds we produce and use embed a
17864 statically-linked Guile, and the initialization program is a Guile
17865 program. That gives a lot of flexibility. The
17866 @code{expression->initrd} procedure builds such an initrd, given the
17867 program to run in that initrd.
17869 @deffn {Monadic Procedure} expression->initrd @var{exp} @
17870 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
17871 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
17872 containing @var{guile} and that evaluates @var{exp}, a G-expression,
17873 upon booting. All the derivations referenced by @var{exp} are
17874 automatically copied to the initrd.
17877 @node Bootloader Configuration
17878 @subsection Bootloader Configuration
17881 @cindex boot loader
17883 The operating system supports multiple bootloaders. The bootloader is
17884 configured using @code{bootloader-configuration} declaration. All the
17885 fields of this structure are bootloader agnostic except for one field,
17886 @code{bootloader} that indicates the bootloader to be configured and
17889 Some of the bootloaders do not honor every field of
17890 @code{bootloader-configuration}. For instance, the extlinux
17891 bootloader does not support themes and thus ignores the @code{theme}
17894 @deftp {Data Type} bootloader-configuration
17895 The type of a bootloader configuration declaration.
17899 @item @code{bootloader}
17900 @cindex EFI, bootloader
17901 @cindex UEFI, bootloader
17902 @cindex BIOS, bootloader
17903 The bootloader to use, as a @code{bootloader} object. For now
17904 @code{grub-bootloader}, @code{grub-efi-bootloader},
17905 @code{extlinux-bootloader} and @code{u-boot-bootloader} are supported.
17906 @code{grub-efi-bootloader} allows to boot on modern systems using the
17907 @dfn{Unified Extensible Firmware Interface} (UEFI).
17909 Available bootloaders are described in @code{(gnu bootloader @dots{})}
17912 @item @code{target}
17913 This is a string denoting the target onto which to install the
17914 bootloader. The exact interpretation depends on the bootloader in
17915 question; for @code{grub-bootloader}, for example, it should be a device
17916 name understood by the bootloader @command{installer} command, such as
17917 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking
17918 grub-install,,, grub, GNU GRUB Manual}). For
17919 @code{grub-efi-bootloader}, it should be the path to a mounted EFI file
17922 @item @code{menu-entries} (default: @code{()})
17923 A possibly empty list of @code{menu-entry} objects (see below), denoting
17924 entries to appear in the bootloader menu, in addition to the current
17925 system entry and the entry pointing to previous system generations.
17928 @item @code{default-entry} (default: @code{0})
17929 The index of the default boot menu entry. Index 0 is for the entry of the
17932 @item @code{timeout} (default: @code{5})
17933 The number of seconds to wait for keyboard input before booting. Set to
17934 0 to boot immediately, and to -1 to wait indefinitely.
17936 @item @code{theme} (default: @var{#f})
17937 The bootloader theme object describing the theme to use. If no theme
17938 is provided, some bootloaders might use a default theme, that's true
17941 @item @code{terminal-outputs} (default: @code{'gfxterm})
17942 The output terminals used for the bootloader boot menu, as a list of
17943 symbols. GRUB accepts the values: @code{console}, @code{serial},
17944 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
17945 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
17946 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
17947 configuration,,, grub,GNU GRUB manual}).
17949 @item @code{terminal-inputs} (default: @code{'()})
17950 The input terminals used for the bootloader boot menu, as a list of
17951 symbols. For GRUB, the default is the native platform terminal as
17952 determined at run-time. GRUB accepts the values: @code{console},
17953 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
17954 @code{usb_keyboard}. This field corresponds to the GRUB variable
17955 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
17958 @item @code{serial-unit} (default: @code{#f})
17959 The serial unit used by the bootloader, as an integer from 0 to 3.
17960 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
17961 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
17963 @item @code{serial-speed} (default: @code{#f})
17964 The speed of the serial interface, as an integer. For GRUB, the
17965 default value is chosen at run-time; currently GRUB chooses
17966 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
17973 Should you want to list additional boot menu entries @i{via} the
17974 @code{menu-entries} field above, you will need to create them with the
17975 @code{menu-entry} form. For example, imagine you want to be able to
17976 boot another distro (hard to imagine!), you can define a menu entry
17981 (label "The Other Distro")
17982 (linux "/boot/old/vmlinux-2.6.32")
17983 (linux-arguments '("root=/dev/sda2"))
17984 (initrd "/boot/old/initrd"))
17989 @deftp {Data Type} menu-entry
17990 The type of an entry in the bootloader menu.
17995 The label to show in the menu---e.g., @code{"GNU"}.
17998 The Linux kernel image to boot, for example:
18001 (file-append linux-libre "/bzImage")
18004 For GRUB, it is also possible to specify a device explicitly in the
18005 file path using GRUB's device naming convention (@pxref{Naming
18006 convention,,, grub, GNU GRUB manual}), for example:
18009 "(hd0,msdos1)/boot/vmlinuz"
18012 If the device is specified explicitly as above, then the @code{device}
18013 field is ignored entirely.
18015 @item @code{linux-arguments} (default: @code{()})
18016 The list of extra Linux kernel command-line arguments---e.g.,
18017 @code{("console=ttyS0")}.
18019 @item @code{initrd}
18020 A G-Expression or string denoting the file name of the initial RAM disk
18021 to use (@pxref{G-Expressions}).
18022 @item @code{device} (default: @code{#f})
18023 The device where the kernel and initrd are to be found---i.e., for GRUB,
18024 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
18026 This may be a file system label (a string), a file system UUID (a
18027 bytevector, @pxref{File Systems}), or @code{#f}, in which case
18028 the bootloader will search the device containing the file specified by
18029 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
18030 must @emph{not} be an OS device name such as @file{/dev/sda1}.
18035 @c FIXME: Write documentation once it's stable.
18036 Fow now only GRUB has theme support. GRUB themes are created using
18037 the @code{grub-theme} form, which is not documented yet.
18039 @defvr {Scheme Variable} %default-theme
18040 This is the default GRUB theme used by the operating system if no
18041 @code{theme} field is specified in @code{bootloader-configuration}
18044 It comes with a fancy background image displaying the GNU and Guix
18049 @node Invoking guix system
18050 @subsection Invoking @code{guix system}
18052 Once you have written an operating system declaration as seen in the
18053 previous section, it can be @dfn{instantiated} using the @command{guix
18054 system} command. The synopsis is:
18057 guix system @var{options}@dots{} @var{action} @var{file}
18060 @var{file} must be the name of a file containing an
18061 @code{operating-system} declaration. @var{action} specifies how the
18062 operating system is instantiated. Currently the following values are
18067 Display available service type definitions that match the given regular
18068 expressions, sorted by relevance:
18071 $ guix system search console font
18072 name: console-fonts
18073 location: gnu/services/base.scm:729:2
18074 extends: shepherd-root
18075 description: Install the given fonts on the specified ttys (fonts are
18076 + per virtual console on GNU/Linux). The value of this service is a list
18077 + of tty/font pairs like:
18079 + '(("tty1" . "LatGrkCyr-8x16"))
18083 location: gnu/services/base.scm:1048:2
18084 extends: shepherd-root
18085 description: Provide console login using the `mingetty' program.
18089 location: gnu/services/base.scm:775:2
18091 description: Provide a console log-in service as specified by its
18092 + configuration value, a `login-configuration' object.
18098 As for @command{guix package --search}, the result is written in
18099 @code{recutils} format, which makes it easy to filter the output
18100 (@pxref{Top, GNU recutils databases,, recutils, GNU recutils manual}).
18103 Build the operating system described in @var{file}, activate it, and
18104 switch to it@footnote{This action (and the related actions
18105 @code{switch-generation} and @code{roll-back}) are usable only on
18106 systems already running GuixSD.}.
18108 This effects all the configuration specified in @var{file}: user
18109 accounts, system services, global package list, setuid programs, etc.
18110 The command starts system services specified in @var{file} that are not
18111 currently running; if a service is currently running, it does not
18112 attempt to upgrade it since this would not be possible without stopping it
18115 This command creates a new generation whose number is one greater than
18116 the current generation (as reported by @command{guix system
18117 list-generations}). If that generation already exists, it will be
18118 overwritten. This behavior mirrors that of @command{guix package}
18119 (@pxref{Invoking guix package}).
18121 It also adds a bootloader menu entry for the new OS configuration,
18122 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
18123 entries for older configurations to a submenu, allowing you to choose
18124 an older system generation at boot time should you need it.
18127 @c The paragraph below refers to the problem discussed at
18128 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
18129 It is highly recommended to run @command{guix pull} once before you run
18130 @command{guix system reconfigure} for the first time (@pxref{Invoking
18131 guix pull}). Failing to do that you would see an older version of Guix
18132 once @command{reconfigure} has completed.
18135 @item switch-generation
18136 @cindex generations
18137 Switch to an existing system generation. This action atomically
18138 switches the system profile to the specified system generation. It
18139 also rearranges the system's existing bootloader menu entries. It
18140 makes the menu entry for the specified system generation the default,
18141 and it moves the entries for the other generatiors to a submenu, if
18142 supported by the bootloader being used. The next time the system
18143 boots, it will use the specified system generation.
18145 The bootloader itself is not being reinstalled when using this
18146 command. Thus, the installed bootloader is used with an updated
18147 configuration file.
18149 The target generation can be specified explicitly by its generation
18150 number. For example, the following invocation would switch to system
18154 guix system switch-generation 7
18157 The target generation can also be specified relative to the current
18158 generation with the form @code{+N} or @code{-N}, where @code{+3} means
18159 ``3 generations ahead of the current generation,'' and @code{-1} means
18160 ``1 generation prior to the current generation.'' When specifying a
18161 negative value such as @code{-1}, you must precede it with @code{--} to
18162 prevent it from being parsed as an option. For example:
18165 guix system switch-generation -- -1
18168 Currently, the effect of invoking this action is @emph{only} to switch
18169 the system profile to an existing generation and rearrange the
18170 bootloader menu entries. To actually start using the target system
18171 generation, you must reboot after running this action. In the future,
18172 it will be updated to do the same things as @command{reconfigure},
18173 like activating and deactivating services.
18175 This action will fail if the specified generation does not exist.
18178 @cindex rolling back
18179 Switch to the preceding system generation. The next time the system
18180 boots, it will use the preceding system generation. This is the inverse
18181 of @command{reconfigure}, and it is exactly the same as invoking
18182 @command{switch-generation} with an argument of @code{-1}.
18184 Currently, as with @command{switch-generation}, you must reboot after
18185 running this action to actually start using the preceding system
18189 Build the derivation of the operating system, which includes all the
18190 configuration files and programs needed to boot and run the system.
18191 This action does not actually install anything.
18194 Populate the given directory with all the files necessary to run the
18195 operating system specified in @var{file}. This is useful for first-time
18196 installations of GuixSD. For instance:
18199 guix system init my-os-config.scm /mnt
18202 copies to @file{/mnt} all the store items required by the configuration
18203 specified in @file{my-os-config.scm}. This includes configuration
18204 files, packages, and so on. It also creates other essential files
18205 needed for the system to operate correctly---e.g., the @file{/etc},
18206 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
18208 This command also installs bootloader on the target specified in
18209 @file{my-os-config}, unless the @option{--no-bootloader} option was
18213 @cindex virtual machine
18215 @anchor{guix system vm}
18216 Build a virtual machine that contains the operating system declared in
18217 @var{file}, and return a script to run that virtual machine (VM).
18218 Arguments given to the script are passed to QEMU as in the example
18219 below, which enables networking and requests 1@tie{}GiB of RAM for the
18223 $ /gnu/store/@dots{}-run-vm.sh -m 1024 -net user
18226 The VM shares its store with the host system.
18228 Additional file systems can be shared between the host and the VM using
18229 the @code{--share} and @code{--expose} command-line options: the former
18230 specifies a directory to be shared with write access, while the latter
18231 provides read-only access to the shared directory.
18233 The example below creates a VM in which the user's home directory is
18234 accessible read-only, and where the @file{/exchange} directory is a
18235 read-write mapping of @file{$HOME/tmp} on the host:
18238 guix system vm my-config.scm \
18239 --expose=$HOME --share=$HOME/tmp=/exchange
18242 On GNU/Linux, the default is to boot directly to the kernel; this has
18243 the advantage of requiring only a very tiny root disk image since the
18244 store of the host can then be mounted.
18246 The @code{--full-boot} option forces a complete boot sequence, starting
18247 with the bootloader. This requires more disk space since a root image
18248 containing at least the kernel, initrd, and bootloader data files must
18249 be created. The @code{--image-size} option can be used to specify the
18254 Return a virtual machine or disk image of the operating system declared
18255 in @var{file} that stands alone. By default, @command{guix system}
18256 estimates the size of the image needed to store the system, but you can
18257 use the @option{--image-size} option to specify a value.
18259 You can specify the root file system type by using the
18260 @option{--file-system-type} option. It defaults to @code{ext4}.
18262 When using @code{vm-image}, the returned image is in qcow2 format, which
18263 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
18264 for more information on how to run the image in a virtual machine.
18266 When using @code{disk-image}, a raw disk image is produced; it can be
18267 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
18268 the device corresponding to a USB stick, one can copy the image to it
18269 using the following command:
18272 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
18276 Return a script to run the operating system declared in @var{file}
18277 within a container. Containers are a set of lightweight isolation
18278 mechanisms provided by the kernel Linux-libre. Containers are
18279 substantially less resource-demanding than full virtual machines since
18280 the kernel, shared objects, and other resources can be shared with the
18281 host system; this also means they provide thinner isolation.
18283 Currently, the script must be run as root in order to support more than
18284 a single user and group. The container shares its store with the host
18287 As with the @code{vm} action (@pxref{guix system vm}), additional file
18288 systems to be shared between the host and container can be specified
18289 using the @option{--share} and @option{--expose} options:
18292 guix system container my-config.scm \
18293 --expose=$HOME --share=$HOME/tmp=/exchange
18297 This option requires Linux-libre 3.19 or newer.
18302 @var{options} can contain any of the common build options (@pxref{Common
18303 Build Options}). In addition, @var{options} can contain one of the
18307 @item --system=@var{system}
18308 @itemx -s @var{system}
18309 Attempt to build for @var{system} instead of the host system type.
18310 This works as per @command{guix build} (@pxref{Invoking guix build}).
18314 Return the derivation file name of the given operating system without
18317 @item --file-system-type=@var{type}
18318 @itemx -t @var{type}
18319 For the @code{disk-image} action, create a file system of the given
18320 @var{type} on the image.
18322 When this option is omitted, @command{guix system} uses @code{ext4}.
18324 @cindex ISO-9660 format
18325 @cindex CD image format
18326 @cindex DVD image format
18327 @code{--file-system-type=iso9660} produces an ISO-9660 image, suitable
18328 for burning on CDs and DVDs.
18330 @item --image-size=@var{size}
18331 For the @code{vm-image} and @code{disk-image} actions, create an image
18332 of the given @var{size}. @var{size} may be a number of bytes, or it may
18333 include a unit as a suffix (@pxref{Block size, size specifications,,
18334 coreutils, GNU Coreutils}).
18336 When this option is omitted, @command{guix system} computes an estimate
18337 of the image size as a function of the size of the system declared in
18340 @item --root=@var{file}
18341 @itemx -r @var{file}
18342 Make @var{file} a symlink to the result, and register it as a garbage
18345 @item --on-error=@var{strategy}
18346 Apply @var{strategy} when an error occurs when reading @var{file}.
18347 @var{strategy} may be one of the following:
18350 @item nothing-special
18351 Report the error concisely and exit. This is the default strategy.
18354 Likewise, but also display a backtrace.
18357 Report the error and enter Guile's debugger. From there, you can run
18358 commands such as @code{,bt} to get a backtrace, @code{,locals} to
18359 display local variable values, and more generally inspect the state of the
18360 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
18361 a list of available debugging commands.
18366 All the actions above, except @code{build} and @code{init},
18367 can use KVM support in the Linux-libre kernel. Specifically, if the
18368 machine has hardware virtualization support, the corresponding
18369 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
18370 must exist and be readable and writable by the user and by the
18371 build users of the daemon (@pxref{Build Environment Setup}).
18374 Once you have built, configured, re-configured, and re-re-configured
18375 your GuixSD installation, you may find it useful to list the operating
18376 system generations available on disk---and that you can choose from the
18377 bootloader boot menu:
18381 @item list-generations
18382 List a summary of each generation of the operating system available on
18383 disk, in a human-readable way. This is similar to the
18384 @option{--list-generations} option of @command{guix package}
18385 (@pxref{Invoking guix package}).
18387 Optionally, one can specify a pattern, with the same syntax that is used
18388 in @command{guix package --list-generations}, to restrict the list of
18389 generations displayed. For instance, the following command displays
18390 generations that are up to 10 days old:
18393 $ guix system list-generations 10d
18398 The @command{guix system} command has even more to offer! The following
18399 sub-commands allow you to visualize how your system services relate to
18402 @anchor{system-extension-graph}
18405 @item extension-graph
18406 Emit in Dot/Graphviz format to standard output the @dfn{service
18407 extension graph} of the operating system defined in @var{file}
18408 (@pxref{Service Composition}, for more information on service
18414 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
18417 produces a PDF file showing the extension relations among services.
18419 @anchor{system-shepherd-graph}
18420 @item shepherd-graph
18421 Emit in Dot/Graphviz format to standard output the @dfn{dependency
18422 graph} of shepherd services of the operating system defined in
18423 @var{file}. @xref{Shepherd Services}, for more information and for an
18428 @node Running GuixSD in a VM
18429 @subsection Running GuixSD in a Virtual Machine
18431 @cindex virtual machine
18432 To run GuixSD in a virtual machine (VM), one can either use the
18433 pre-built GuixSD VM image distributed at
18434 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
18435 , or build their own virtual machine image using @command{guix system
18436 vm-image} (@pxref{Invoking guix system}). The returned image is in
18437 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
18441 If you built your own image, you must copy it out of the store
18442 (@pxref{The Store}) and give yourself permission to write to the copy
18443 before you can use it. When invoking QEMU, you must choose a system
18444 emulator that is suitable for your hardware platform. Here is a minimal
18445 QEMU invocation that will boot the result of @command{guix system
18446 vm-image} on x86_64 hardware:
18449 $ qemu-system-x86_64 \
18450 -net user -net nic,model=virtio \
18451 -enable-kvm -m 256 /tmp/qemu-image
18454 Here is what each of these options means:
18457 @item qemu-system-x86_64
18458 This specifies the hardware platform to emulate. This should match the
18462 Enable the unprivileged user-mode network stack. The guest OS can
18463 access the host but not vice versa. This is the simplest way to get the
18466 @item -net nic,model=virtio
18467 You must create a network interface of a given model. If you do not
18468 create a NIC, the boot will fail. Assuming your hardware platform is
18469 x86_64, you can get a list of available NIC models by running
18470 @command{qemu-system-x86_64 -net nic,model=help}.
18473 If your system has hardware virtualization extensions, enabling the
18474 virtual machine support (KVM) of the Linux kernel will make things run
18478 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
18479 which may be insufficient for some operations.
18481 @item /tmp/qemu-image
18482 The file name of the qcow2 image.
18485 The default @command{run-vm.sh} script that is returned by an invocation of
18486 @command{guix system vm} does not add a @command{-net user} flag by default.
18487 To get network access from within the vm add the @code{(dhcp-client-service)}
18488 to your system definition and start the VM using
18489 @command{`guix system vm config.scm` -net user}. An important caveat of using
18490 @command{-net user} for networking is that @command{ping} will not work, because
18491 it uses the ICMP protocol. You'll have to use a different command to check for
18492 network connectivity, for example @command{guix download}.
18494 @subsubsection Connecting Through SSH
18498 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
18499 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
18500 boot unsupervised. It requires you to type some characters to initialize the
18501 randomness generator. In addition you need to forward the SSH port, 22 by
18502 default, to the host. You can do this with
18505 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
18508 To connect to the VM you can run
18511 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
18514 The @command{-p} tells @command{ssh} the port you want to connect to.
18515 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
18516 every time you modify your @command{config.scm} file and the
18517 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
18518 connection to an unknown host every time you connect.
18520 @subsubsection Using @command{virt-viewer} with Spice
18522 As an alternative to the default @command{qemu} graphical client you can
18523 use the @command{remote-viewer} from the @command{virt-viewer} package. To
18524 connect pass the @command{-spice port=5930,disable-ticketing} flag to
18525 @command{qemu}. See previous section for further information on how to do this.
18527 Spice also allows you to do some nice stuff like share your clipboard with your
18528 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
18531 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
18532 -chardev spicevmc,name=vdagent,id=vdagent
18533 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
18534 name=com.redhat.spice.0
18537 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
18539 @node Defining Services
18540 @subsection Defining Services
18542 The previous sections show the available services and how one can combine
18543 them in an @code{operating-system} declaration. But how do we define
18544 them in the first place? And what is a service anyway?
18547 * Service Composition:: The model for composing services.
18548 * Service Types and Services:: Types and services.
18549 * Service Reference:: API reference.
18550 * Shepherd Services:: A particular type of service.
18553 @node Service Composition
18554 @subsubsection Service Composition
18558 Here we define a @dfn{service} as, broadly, something that extends the
18559 functionality of the operating system. Often a service is a process---a
18560 @dfn{daemon}---started when the system boots: a secure shell server, a
18561 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
18562 whose execution can be triggered by another daemon---e.g., an FTP server
18563 started by @command{inetd} or a D-Bus service activated by
18564 @command{dbus-daemon}. Occasionally, a service does not map to a
18565 daemon. For instance, the ``account'' service collects user accounts
18566 and makes sure they exist when the system runs; the ``udev'' service
18567 collects device management rules and makes them available to the eudev
18568 daemon; the @file{/etc} service populates the @file{/etc} directory
18571 @cindex service extensions
18572 GuixSD services are connected by @dfn{extensions}. For instance, the
18573 secure shell service @emph{extends} the Shepherd---the GuixSD
18574 initialization system, running as PID@tie{}1---by giving it the command
18575 lines to start and stop the secure shell daemon (@pxref{Networking
18576 Services, @code{lsh-service}}); the UPower service extends the D-Bus
18577 service by passing it its @file{.service} specification, and extends the
18578 udev service by passing it device management rules (@pxref{Desktop
18579 Services, @code{upower-service}}); the Guix daemon service extends the
18580 Shepherd by passing it the command lines to start and stop the daemon,
18581 and extends the account service by passing it a list of required build
18582 user accounts (@pxref{Base Services}).
18584 All in all, services and their ``extends'' relations form a directed
18585 acyclic graph (DAG). If we represent services as boxes and extensions
18586 as arrows, a typical system might provide something like this:
18588 @image{images/service-graph,,5in,Typical service extension graph.}
18590 @cindex system service
18591 At the bottom, we see the @dfn{system service}, which produces the
18592 directory containing everything to run and boot the system, as returned
18593 by the @command{guix system build} command. @xref{Service Reference},
18594 to learn about the other service types shown here.
18595 @xref{system-extension-graph, the @command{guix system extension-graph}
18596 command}, for information on how to generate this representation for a
18597 particular operating system definition.
18599 @cindex service types
18600 Technically, developers can define @dfn{service types} to express these
18601 relations. There can be any number of services of a given type on the
18602 system---for instance, a system running two instances of the GNU secure
18603 shell server (lsh) has two instances of @var{lsh-service-type}, with
18604 different parameters.
18606 The following section describes the programming interface for service
18607 types and services.
18609 @node Service Types and Services
18610 @subsubsection Service Types and Services
18612 A @dfn{service type} is a node in the DAG described above. Let us start
18613 with a simple example, the service type for the Guix build daemon
18614 (@pxref{Invoking guix-daemon}):
18617 (define guix-service-type
18621 (list (service-extension shepherd-root-service-type guix-shepherd-service)
18622 (service-extension account-service-type guix-accounts)
18623 (service-extension activation-service-type guix-activation)))
18624 (default-value (guix-configuration))))
18628 It defines three things:
18632 A name, whose sole purpose is to make inspection and debugging easier.
18635 A list of @dfn{service extensions}, where each extension designates the
18636 target service type and a procedure that, given the parameters of the
18637 service, returns a list of objects to extend the service of that type.
18639 Every service type has at least one service extension. The only
18640 exception is the @dfn{boot service type}, which is the ultimate service.
18643 Optionally, a default value for instances of this type.
18646 In this example, @var{guix-service-type} extends three services:
18649 @item shepherd-root-service-type
18650 The @var{guix-shepherd-service} procedure defines how the Shepherd
18651 service is extended. Namely, it returns a @code{<shepherd-service>}
18652 object that defines how @command{guix-daemon} is started and stopped
18653 (@pxref{Shepherd Services}).
18655 @item account-service-type
18656 This extension for this service is computed by @var{guix-accounts},
18657 which returns a list of @code{user-group} and @code{user-account}
18658 objects representing the build user accounts (@pxref{Invoking
18661 @item activation-service-type
18662 Here @var{guix-activation} is a procedure that returns a gexp, which is
18663 a code snippet to run at ``activation time''---e.g., when the service is
18667 A service of this type is instantiated like this:
18670 (service guix-service-type
18671 (guix-configuration
18673 (use-substitutes? #f)))
18676 The second argument to the @code{service} form is a value representing
18677 the parameters of this specific service instance.
18678 @xref{guix-configuration-type, @code{guix-configuration}}, for
18679 information about the @code{guix-configuration} data type. When the
18680 value is omitted, the default value specified by
18681 @code{guix-service-type} is used:
18684 (service guix-service-type)
18687 @var{guix-service-type} is quite simple because it extends other
18688 services but is not extensible itself.
18690 @c @subsubsubsection Extensible Service Types
18692 The service type for an @emph{extensible} service looks like this:
18695 (define udev-service-type
18696 (service-type (name 'udev)
18698 (list (service-extension shepherd-root-service-type
18699 udev-shepherd-service)))
18701 (compose concatenate) ;concatenate the list of rules
18702 (extend (lambda (config rules)
18704 (($ <udev-configuration> udev initial-rules)
18705 (udev-configuration
18706 (udev udev) ;the udev package to use
18707 (rules (append initial-rules rules)))))))))
18710 This is the service type for the
18711 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
18712 management daemon}. Compared to the previous example, in addition to an
18713 extension of @var{shepherd-root-service-type}, we see two new fields:
18717 This is the procedure to @dfn{compose} the list of extensions to
18718 services of this type.
18720 Services can extend the udev service by passing it lists of rules; we
18721 compose those extensions simply by concatenating them.
18724 This procedure defines how the value of the service is @dfn{extended} with
18725 the composition of the extensions.
18727 Udev extensions are composed into a list of rules, but the udev service
18728 value is itself a @code{<udev-configuration>} record. So here, we
18729 extend that record by appending the list of rules it contains to the
18730 list of contributed rules.
18733 This is a string giving an overview of the service type. The string can
18734 contain Texinfo markup (@pxref{Overview,,, texinfo, GNU Texinfo}). The
18735 @command{guix system search} command searches these strings and displays
18736 them (@pxref{Invoking guix system}).
18739 There can be only one instance of an extensible service type such as
18740 @var{udev-service-type}. If there were more, the
18741 @code{service-extension} specifications would be ambiguous.
18743 Still here? The next section provides a reference of the programming
18744 interface for services.
18746 @node Service Reference
18747 @subsubsection Service Reference
18749 We have seen an overview of service types (@pxref{Service Types and
18750 Services}). This section provides a reference on how to manipulate
18751 services and service types. This interface is provided by the
18752 @code{(gnu services)} module.
18754 @deffn {Scheme Procedure} service @var{type} [@var{value}]
18755 Return a new service of @var{type}, a @code{<service-type>} object (see
18756 below.) @var{value} can be any object; it represents the parameters of
18757 this particular service instance.
18759 When @var{value} is omitted, the default value specified by @var{type}
18760 is used; if @var{type} does not specify a default value, an error is
18763 For instance, this:
18766 (service openssh-service-type)
18770 is equivalent to this:
18773 (service openssh-service-type
18774 (openssh-configuration))
18777 In both cases the result is an instance of @code{openssh-service-type}
18778 with the default configuration.
18781 @deffn {Scheme Procedure} service? @var{obj}
18782 Return true if @var{obj} is a service.
18785 @deffn {Scheme Procedure} service-kind @var{service}
18786 Return the type of @var{service}---i.e., a @code{<service-type>} object.
18789 @deffn {Scheme Procedure} service-value @var{service}
18790 Return the value associated with @var{service}. It represents its
18794 Here is an example of how a service is created and manipulated:
18798 (service nginx-service-type
18799 (nginx-configuration
18801 (log-directory log-directory)
18802 (run-directory run-directory)
18803 (file config-file))))
18808 (eq? (service-kind s) nginx-service-type)
18812 The @code{modify-services} form provides a handy way to change the
18813 parameters of some of the services of a list such as
18814 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
18815 evaluates to a list of services. Of course, you could always use
18816 standard list combinators such as @code{map} and @code{fold} to do that
18817 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
18818 @code{modify-services} simply provides a more concise form for this
18821 @deffn {Scheme Syntax} modify-services @var{services} @
18822 (@var{type} @var{variable} => @var{body}) @dots{}
18824 Modify the services listed in @var{services} according to the given
18825 clauses. Each clause has the form:
18828 (@var{type} @var{variable} => @var{body})
18831 where @var{type} is a service type---e.g.,
18832 @code{guix-service-type}---and @var{variable} is an identifier that is
18833 bound within the @var{body} to the service parameters---e.g., a
18834 @code{guix-configuration} instance---of the original service of that
18837 The @var{body} should evaluate to the new service parameters, which will
18838 be used to configure the new service. This new service will replace the
18839 original in the resulting list. Because a service's service parameters
18840 are created using @code{define-record-type*}, you can write a succinct
18841 @var{body} that evaluates to the new service parameters by using the
18842 @code{inherit} feature that @code{define-record-type*} provides.
18844 @xref{Using the Configuration System}, for example usage.
18848 Next comes the programming interface for service types. This is
18849 something you want to know when writing new service definitions, but not
18850 necessarily when simply looking for ways to customize your
18851 @code{operating-system} declaration.
18853 @deftp {Data Type} service-type
18854 @cindex service type
18855 This is the representation of a @dfn{service type} (@pxref{Service Types
18860 This is a symbol, used only to simplify inspection and debugging.
18862 @item @code{extensions}
18863 A non-empty list of @code{<service-extension>} objects (see below).
18865 @item @code{compose} (default: @code{#f})
18866 If this is @code{#f}, then the service type denotes services that cannot
18867 be extended---i.e., services that do not receive ``values'' from other
18870 Otherwise, it must be a one-argument procedure. The procedure is called
18871 by @code{fold-services} and is passed a list of values collected from
18872 extensions. It must return a value that is a valid parameter value for
18873 the service instance.
18875 @item @code{extend} (default: @code{#f})
18876 If this is @code{#f}, services of this type cannot be extended.
18878 Otherwise, it must be a two-argument procedure: @code{fold-services}
18879 calls it, passing it the initial value of the service as the first argument
18880 and the result of applying @code{compose} to the extension values as the
18884 @xref{Service Types and Services}, for examples.
18887 @deffn {Scheme Procedure} service-extension @var{target-type} @
18889 Return a new extension for services of type @var{target-type}.
18890 @var{compute} must be a one-argument procedure: @code{fold-services}
18891 calls it, passing it the value associated with the service that provides
18892 the extension; it must return a valid value for the target service.
18895 @deffn {Scheme Procedure} service-extension? @var{obj}
18896 Return true if @var{obj} is a service extension.
18899 Occasionally, you might want to simply extend an existing service. This
18900 involves creating a new service type and specifying the extension of
18901 interest, which can be verbose; the @code{simple-service} procedure
18902 provides a shorthand for this.
18904 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
18905 Return a service that extends @var{target} with @var{value}. This works
18906 by creating a singleton service type @var{name}, of which the returned
18907 service is an instance.
18909 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
18913 (simple-service 'my-mcron-job mcron-service-type
18914 #~(job '(next-hour (3)) "guix gc -F 2G"))
18918 At the core of the service abstraction lies the @code{fold-services}
18919 procedure, which is responsible for ``compiling'' a list of services
18920 down to a single directory that contains everything needed to boot and
18921 run the system---the directory shown by the @command{guix system build}
18922 command (@pxref{Invoking guix system}). In essence, it propagates
18923 service extensions down the service graph, updating each node parameters
18924 on the way, until it reaches the root node.
18926 @deffn {Scheme Procedure} fold-services @var{services} @
18927 [#:target-type @var{system-service-type}]
18928 Fold @var{services} by propagating their extensions down to the root of
18929 type @var{target-type}; return the root service adjusted accordingly.
18932 Lastly, the @code{(gnu services)} module also defines several essential
18933 service types, some of which are listed below.
18935 @defvr {Scheme Variable} system-service-type
18936 This is the root of the service graph. It produces the system directory
18937 as returned by the @command{guix system build} command.
18940 @defvr {Scheme Variable} boot-service-type
18941 The type of the ``boot service'', which produces the @dfn{boot script}.
18942 The boot script is what the initial RAM disk runs when booting.
18945 @defvr {Scheme Variable} etc-service-type
18946 The type of the @file{/etc} service. This service is used to create
18947 files under @file{/etc} and can be extended by
18948 passing it name/file tuples such as:
18951 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
18954 In this example, the effect would be to add an @file{/etc/issue} file
18955 pointing to the given file.
18958 @defvr {Scheme Variable} setuid-program-service-type
18959 Type for the ``setuid-program service''. This service collects lists of
18960 executable file names, passed as gexps, and adds them to the set of
18961 setuid-root programs on the system (@pxref{Setuid Programs}).
18964 @defvr {Scheme Variable} profile-service-type
18965 Type of the service that populates the @dfn{system profile}---i.e., the
18966 programs under @file{/run/current-system/profile}. Other services can
18967 extend it by passing it lists of packages to add to the system profile.
18971 @node Shepherd Services
18972 @subsubsection Shepherd Services
18974 @cindex shepherd services
18976 @cindex init system
18977 The @code{(gnu services shepherd)} module provides a way to define
18978 services managed by the GNU@tie{}Shepherd, which is the GuixSD
18979 initialization system---the first process that is started when the
18980 system boots, also known as PID@tie{}1
18981 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
18983 Services in the Shepherd can depend on each other. For instance, the
18984 SSH daemon may need to be started after the syslog daemon has been
18985 started, which in turn can only happen once all the file systems have
18986 been mounted. The simple operating system defined earlier (@pxref{Using
18987 the Configuration System}) results in a service graph like this:
18989 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
18991 You can actually generate such a graph for any operating system
18992 definition using the @command{guix system shepherd-graph} command
18993 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
18995 The @var{%shepherd-root-service} is a service object representing
18996 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
18997 by passing it lists of @code{<shepherd-service>} objects.
18999 @deftp {Data Type} shepherd-service
19000 The data type representing a service managed by the Shepherd.
19003 @item @code{provision}
19004 This is a list of symbols denoting what the service provides.
19006 These are the names that may be passed to @command{herd start},
19007 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
19008 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
19009 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
19011 @item @code{requirements} (default: @code{'()})
19012 List of symbols denoting the Shepherd services this one depends on.
19014 @item @code{respawn?} (default: @code{#t})
19015 Whether to restart the service when it stops, for instance when the
19016 underlying process dies.
19019 @itemx @code{stop} (default: @code{#~(const #f)})
19020 The @code{start} and @code{stop} fields refer to the Shepherd's
19021 facilities to start and stop processes (@pxref{Service De- and
19022 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
19023 G-expressions that get expanded in the Shepherd configuration file
19024 (@pxref{G-Expressions}).
19026 @item @code{documentation}
19027 A documentation string, as shown when running:
19030 herd doc @var{service-name}
19033 where @var{service-name} is one of the symbols in @var{provision}
19034 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
19036 @item @code{modules} (default: @var{%default-modules})
19037 This is the list of modules that must be in scope when @code{start} and
19038 @code{stop} are evaluated.
19043 @defvr {Scheme Variable} shepherd-root-service-type
19044 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
19046 This is the service type that extensions target when they want to create
19047 shepherd services (@pxref{Service Types and Services}, for an example).
19048 Each extension must pass a list of @code{<shepherd-service>}.
19051 @defvr {Scheme Variable} %shepherd-root-service
19052 This service represents PID@tie{}1.
19056 @node Documentation
19057 @section Documentation
19059 @cindex documentation, searching for
19060 @cindex searching for documentation
19061 @cindex Info, documentation format
19063 @cindex manual pages
19064 In most cases packages installed with Guix come with documentation.
19065 There are two main documentation formats: ``Info'', a browseable
19066 hypertext format used for GNU software, and ``manual pages'' (or ``man
19067 pages''), the linear documentation format traditionally found on Unix.
19068 Info manuals are accessed with the @command{info} command or with Emacs,
19069 and man pages are accessed using @command{man}.
19071 You can look for documentation of software installed on your system by
19072 keyword. For example, the following command searches for information
19073 about ``TLS'' in Info manuals:
19077 "(emacs)Network Security" -- STARTTLS
19078 "(emacs)Network Security" -- TLS
19079 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
19080 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
19085 The command below searches for the same keyword in man pages:
19089 SSL (7) - OpenSSL SSL/TLS library
19090 certtool (1) - GnuTLS certificate tool
19094 These searches are purely local to your computer so you have the
19095 guarantee that documentation you find corresponds to what you have
19096 actually installed, you can access it off-line, and your privacy is
19099 Once you have these results, you can view the relevant documentation by
19103 $ info "(gnutls)Core TLS API"
19113 Info manuals contain sections and indices as well as hyperlinks like
19114 those found in Web pages. The @command{info} reader (@pxref{Top, Info
19115 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
19116 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
19117 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
19118 Introduction}, for an introduction to Info navigation.
19120 @node Installing Debugging Files
19121 @section Installing Debugging Files
19123 @cindex debugging files
19124 Program binaries, as produced by the GCC compilers for instance, are
19125 typically written in the ELF format, with a section containing
19126 @dfn{debugging information}. Debugging information is what allows the
19127 debugger, GDB, to map binary code to source code; it is required to
19128 debug a compiled program in good conditions.
19130 The problem with debugging information is that is takes up a fair amount
19131 of disk space. For example, debugging information for the GNU C Library
19132 weighs in at more than 60 MiB. Thus, as a user, keeping all the
19133 debugging info of all the installed programs is usually not an option.
19134 Yet, space savings should not come at the cost of an impediment to
19135 debugging---especially in the GNU system, which should make it easier
19136 for users to exert their computing freedom (@pxref{GNU Distribution}).
19138 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
19139 mechanism that allows users to get the best of both worlds: debugging
19140 information can be stripped from the binaries and stored in separate
19141 files. GDB is then able to load debugging information from those files,
19142 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
19145 The GNU distribution takes advantage of this by storing debugging
19146 information in the @code{lib/debug} sub-directory of a separate package
19147 output unimaginatively called @code{debug} (@pxref{Packages with
19148 Multiple Outputs}). Users can choose to install the @code{debug} output
19149 of a package when they need it. For instance, the following command
19150 installs the debugging information for the GNU C Library and for GNU
19154 guix package -i glibc:debug guile:debug
19157 GDB must then be told to look for debug files in the user's profile, by
19158 setting the @code{debug-file-directory} variable (consider setting it
19159 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
19163 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
19166 From there on, GDB will pick up debugging information from the
19167 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
19169 In addition, you will most likely want GDB to be able to show the source
19170 code being debugged. To do that, you will have to unpack the source
19171 code of the package of interest (obtained with @code{guix build
19172 --source}, @pxref{Invoking guix build}), and to point GDB to that source
19173 directory using the @code{directory} command (@pxref{Source Path,
19174 @code{directory},, gdb, Debugging with GDB}).
19176 @c XXX: keep me up-to-date
19177 The @code{debug} output mechanism in Guix is implemented by the
19178 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
19179 opt-in---debugging information is available only for the packages
19180 with definitions explicitly declaring a @code{debug} output. This may be
19181 changed to opt-out in the future if our build farm servers can handle
19182 the load. To check whether a package has a @code{debug} output, use
19183 @command{guix package --list-available} (@pxref{Invoking guix package}).
19186 @node Security Updates
19187 @section Security Updates
19189 @cindex security updates
19190 @cindex security vulnerabilities
19191 Occasionally, important security vulnerabilities are discovered in software
19192 packages and must be patched. Guix developers try hard to keep track of
19193 known vulnerabilities and to apply fixes as soon as possible in the
19194 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
19195 containing only security updates.) The @command{guix lint} tool helps
19196 developers find out about vulnerable versions of software packages in the
19201 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
19202 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
19203 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
19207 @xref{Invoking guix lint}, for more information.
19210 As of version @value{VERSION}, the feature described below is considered
19214 Guix follows a functional
19215 package management discipline (@pxref{Introduction}), which implies
19216 that, when a package is changed, @emph{every package that depends on it}
19217 must be rebuilt. This can significantly slow down the deployment of
19218 fixes in core packages such as libc or Bash, since basically the whole
19219 distribution would need to be rebuilt. Using pre-built binaries helps
19220 (@pxref{Substitutes}), but deployment may still take more time than
19224 To address this, Guix implements @dfn{grafts}, a mechanism that allows
19225 for fast deployment of critical updates without the costs associated
19226 with a whole-distribution rebuild. The idea is to rebuild only the
19227 package that needs to be patched, and then to ``graft'' it onto packages
19228 explicitly installed by the user and that were previously referring to
19229 the original package. The cost of grafting is typically very low, and
19230 order of magnitudes lower than a full rebuild of the dependency chain.
19232 @cindex replacements of packages, for grafts
19233 For instance, suppose a security update needs to be applied to Bash.
19234 Guix developers will provide a package definition for the ``fixed''
19235 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
19236 Packages}). Then, the original package definition is augmented with a
19237 @code{replacement} field pointing to the package containing the bug fix:
19244 (replacement bash-fixed)))
19247 From there on, any package depending directly or indirectly on Bash---as
19248 reported by @command{guix gc --requisites} (@pxref{Invoking guix
19249 gc})---that is installed is automatically ``rewritten'' to refer to
19250 @var{bash-fixed} instead of @var{bash}. This grafting process takes
19251 time proportional to the size of the package, usually less than a
19252 minute for an ``average'' package on a recent machine. Grafting is
19253 recursive: when an indirect dependency requires grafting, then grafting
19254 ``propagates'' up to the package that the user is installing.
19256 Currently, the length of the name and version of the graft and that of
19257 the package it replaces (@var{bash-fixed} and @var{bash} in the example
19258 above) must be equal. This restriction mostly comes from the fact that
19259 grafting works by patching files, including binary files, directly.
19260 Other restrictions may apply: for instance, when adding a graft to a
19261 package providing a shared library, the original shared library and its
19262 replacement must have the same @code{SONAME} and be binary-compatible.
19264 The @option{--no-grafts} command-line option allows you to forcefully
19265 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
19269 guix build bash --no-grafts
19273 returns the store file name of the original Bash, whereas:
19280 returns the store file name of the ``fixed'', replacement Bash. This
19281 allows you to distinguish between the two variants of Bash.
19283 To verify which Bash your whole profile refers to, you can run
19284 (@pxref{Invoking guix gc}):
19287 guix gc -R `readlink -f ~/.guix-profile` | grep bash
19291 @dots{} and compare the store file names that you get with those above.
19292 Likewise for a complete GuixSD system generation:
19295 guix gc -R `guix system build my-config.scm` | grep bash
19298 Lastly, to check which Bash running processes are using, you can use the
19299 @command{lsof} command:
19302 lsof | grep /gnu/store/.*bash
19306 @node Package Modules
19307 @section Package Modules
19309 From a programming viewpoint, the package definitions of the
19310 GNU distribution are provided by Guile modules in the @code{(gnu packages
19311 @dots{})} name space@footnote{Note that packages under the @code{(gnu
19312 packages @dots{})} module name space are not necessarily ``GNU
19313 packages''. This module naming scheme follows the usual Guile module
19314 naming convention: @code{gnu} means that these modules are distributed
19315 as part of the GNU system, and @code{packages} identifies modules that
19316 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
19317 Reference Manual}). For instance, the @code{(gnu packages emacs)}
19318 module exports a variable named @code{emacs}, which is bound to a
19319 @code{<package>} object (@pxref{Defining Packages}).
19321 The @code{(gnu packages @dots{})} module name space is
19322 automatically scanned for packages by the command-line tools. For
19323 instance, when running @code{guix package -i emacs}, all the @code{(gnu
19324 packages @dots{})} modules are scanned until one that exports a package
19325 object whose name is @code{emacs} is found. This package search
19326 facility is implemented in the @code{(gnu packages)} module.
19328 @cindex customization, of packages
19329 @cindex package module search path
19330 Users can store package definitions in modules with different
19331 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
19332 name and module name must match. For instance, the @code{(my-packages
19333 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
19334 relative to the load path specified with @option{--load-path} or
19335 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
19336 guile, GNU Guile Reference Manual}, for details.}. These package definitions
19337 will not be visible by default. Users can invoke commands such as
19338 @command{guix package} and @command{guix build} with the
19339 @code{-e} option so that they know where to find the package. Better
19340 yet, they can use the
19341 @code{-L} option of these commands to make those modules visible
19342 (@pxref{Invoking guix build, @code{--load-path}}), or define the
19343 @code{GUIX_PACKAGE_PATH} environment variable. This environment
19344 variable makes it easy to extend or customize the distribution and is
19345 honored by all the user interfaces.
19347 @defvr {Environment Variable} GUIX_PACKAGE_PATH
19348 This is a colon-separated list of directories to search for additional
19349 package modules. Directories listed in this variable take precedence
19350 over the own modules of the distribution.
19353 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
19354 each package is built based solely on other packages in the
19355 distribution. The root of this dependency graph is a small set of
19356 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
19357 bootstrap)} module. For more information on bootstrapping,
19358 @pxref{Bootstrapping}.
19360 @node Packaging Guidelines
19361 @section Packaging Guidelines
19363 @cindex packages, creating
19364 The GNU distribution is nascent and may well lack some of your favorite
19365 packages. This section describes how you can help make the distribution
19366 grow. @xref{Contributing}, for additional information on how you can
19369 Free software packages are usually distributed in the form of
19370 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
19371 all the source files. Adding a package to the distribution means
19372 essentially two things: adding a @dfn{recipe} that describes how to
19373 build the package, including a list of other packages required to build
19374 it, and adding @dfn{package metadata} along with that recipe, such as a
19375 description and licensing information.
19377 In Guix all this information is embodied in @dfn{package definitions}.
19378 Package definitions provide a high-level view of the package. They are
19379 written using the syntax of the Scheme programming language; in fact,
19380 for each package we define a variable bound to the package definition,
19381 and export that variable from a module (@pxref{Package Modules}).
19382 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
19383 creating packages. For more information on package definitions,
19384 @pxref{Defining Packages}.
19386 Once a package definition is in place, stored in a file in the Guix
19387 source tree, it can be tested using the @command{guix build} command
19388 (@pxref{Invoking guix build}). For example, assuming the new package is
19389 called @code{gnew}, you may run this command from the Guix build tree
19390 (@pxref{Running Guix Before It Is Installed}):
19393 ./pre-inst-env guix build gnew --keep-failed
19396 Using @code{--keep-failed} makes it easier to debug build failures since
19397 it provides access to the failed build tree. Another useful
19398 command-line option when debugging is @code{--log-file}, to access the
19401 If the package is unknown to the @command{guix} command, it may be that
19402 the source file contains a syntax error, or lacks a @code{define-public}
19403 clause to export the package variable. To figure it out, you may load
19404 the module from Guile to get more information about the actual error:
19407 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
19410 Once your package builds correctly, please send us a patch
19411 (@pxref{Contributing}). Well, if you need help, we will be happy to
19412 help you too. Once the patch is committed in the Guix repository, the
19413 new package automatically gets built on the supported platforms by
19414 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
19417 @cindex substituter
19418 Users can obtain the new package definition simply by running
19419 @command{guix pull} (@pxref{Invoking guix pull}). When
19420 @code{hydra.gnu.org} is done building the package, installing the
19421 package automatically downloads binaries from there
19422 (@pxref{Substitutes}). The only place where human intervention is
19423 needed is to review and apply the patch.
19427 * Software Freedom:: What may go into the distribution.
19428 * Package Naming:: What's in a name?
19429 * Version Numbers:: When the name is not enough.
19430 * Synopses and Descriptions:: Helping users find the right package.
19431 * Python Modules:: A touch of British comedy.
19432 * Perl Modules:: Little pearls.
19433 * Java Packages:: Coffee break.
19434 * Fonts:: Fond of fonts.
19437 @node Software Freedom
19438 @subsection Software Freedom
19440 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
19441 @cindex free software
19442 The GNU operating system has been developed so that users can have
19443 freedom in their computing. GNU is @dfn{free software}, meaning that
19444 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
19445 essential freedoms}: to run the program, to study and change the program
19446 in source code form, to redistribute exact copies, and to distribute
19447 modified versions. Packages found in the GNU distribution provide only
19448 software that conveys these four freedoms.
19450 In addition, the GNU distribution follow the
19451 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
19452 software distribution guidelines}. Among other things, these guidelines
19453 reject non-free firmware, recommendations of non-free software, and
19454 discuss ways to deal with trademarks and patents.
19456 Some otherwise free upstream package sources contain a small and optional
19457 subset that violates the above guidelines, for instance because this subset
19458 is itself non-free code. When that happens, the offending items are removed
19459 with appropriate patches or code snippets in the @code{origin} form of the
19460 package (@pxref{Defining Packages}). This way, @code{guix
19461 build --source} returns the ``freed'' source rather than the unmodified
19465 @node Package Naming
19466 @subsection Package Naming
19468 @cindex package name
19469 A package has actually two names associated with it:
19470 First, there is the name of the @emph{Scheme variable}, the one following
19471 @code{define-public}. By this name, the package can be made known in the
19472 Scheme code, for instance as input to another package. Second, there is
19473 the string in the @code{name} field of a package definition. This name
19474 is used by package management commands such as
19475 @command{guix package} and @command{guix build}.
19477 Both are usually the same and correspond to the lowercase conversion of
19478 the project name chosen upstream, with underscores replaced with
19479 hyphens. For instance, GNUnet is available as @code{gnunet}, and
19480 SDL_net as @code{sdl-net}.
19482 We do not add @code{lib} prefixes for library packages, unless these are
19483 already part of the official project name. But @pxref{Python
19484 Modules} and @ref{Perl Modules} for special rules concerning modules for
19485 the Python and Perl languages.
19487 Font package names are handled differently, @pxref{Fonts}.
19490 @node Version Numbers
19491 @subsection Version Numbers
19493 @cindex package version
19494 We usually package only the latest version of a given free software
19495 project. But sometimes, for instance for incompatible library versions,
19496 two (or more) versions of the same package are needed. These require
19497 different Scheme variable names. We use the name as defined
19498 in @ref{Package Naming}
19499 for the most recent version; previous versions use the same name, suffixed
19500 by @code{-} and the smallest prefix of the version number that may
19501 distinguish the two versions.
19503 The name inside the package definition is the same for all versions of a
19504 package and does not contain any version number.
19506 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
19509 (define-public gtk+
19514 (define-public gtk+-2
19517 (version "2.24.20")
19520 If we also wanted GTK+ 3.8.2, this would be packaged as
19522 (define-public gtk+-3.8
19529 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
19530 @c for a discussion of what follows.
19531 @cindex version number, for VCS snapshots
19532 Occasionally, we package snapshots of upstream's version control system
19533 (VCS) instead of formal releases. This should remain exceptional,
19534 because it is up to upstream developers to clarify what the stable
19535 release is. Yet, it is sometimes necessary. So, what should we put in
19536 the @code{version} field?
19538 Clearly, we need to make the commit identifier of the VCS snapshot
19539 visible in the version string, but we also need to make sure that the
19540 version string is monotonically increasing so that @command{guix package
19541 --upgrade} can determine which version is newer. Since commit
19542 identifiers, notably with Git, are not monotonically increasing, we add
19543 a revision number that we increase each time we upgrade to a newer
19544 snapshot. The resulting version string looks like this:
19549 | | `-- upstream commit ID
19551 | `--- Guix package revision
19553 latest upstream version
19556 It is a good idea to strip commit identifiers in the @code{version}
19557 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
19558 aesthetics have a role to play here) as well as problems related to OS
19559 limits such as the maximum shebang length (127 bytes for the Linux
19560 kernel.) It is best to use the full commit identifiers in
19561 @code{origin}s, though, to avoid ambiguities. A typical package
19562 definition may look like this:
19566 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
19567 (revision "1")) ;Guix package revision
19569 (version (string-append "0.9-" revision "."
19570 (string-take commit 7)))
19573 (uri (git-reference
19574 (url "git://example.org/my-package.git")
19576 (sha256 (base32 "1mbikn@dots{}"))
19577 (file-name (string-append "my-package-" version
19583 @node Synopses and Descriptions
19584 @subsection Synopses and Descriptions
19586 @cindex package description
19587 @cindex package synopsis
19588 As we have seen before, each package in GNU@tie{}Guix includes a
19589 synopsis and a description (@pxref{Defining Packages}). Synopses and
19590 descriptions are important: They are what @command{guix package
19591 --search} searches, and a crucial piece of information to help users
19592 determine whether a given package suits their needs. Consequently,
19593 packagers should pay attention to what goes into them.
19595 Synopses must start with a capital letter and must not end with a
19596 period. They must not start with ``a'' or ``the'', which usually does
19597 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
19598 tool that frobs files''. The synopsis should say what the package
19599 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
19600 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
19601 matching a pattern''.
19603 Keep in mind that the synopsis must be meaningful for a very wide
19604 audience. For example, ``Manipulate alignments in the SAM format''
19605 might make sense for a seasoned bioinformatics researcher, but might be
19606 fairly unhelpful or even misleading to a non-specialized audience. It
19607 is a good idea to come up with a synopsis that gives an idea of the
19608 application domain of the package. In this example, this might give
19609 something like ``Manipulate nucleotide sequence alignments'', which
19610 hopefully gives the user a better idea of whether this is what they are
19613 Descriptions should take between five and ten lines. Use full
19614 sentences, and avoid using acronyms without first introducing them.
19615 Please avoid marketing phrases such as ``world-leading'',
19616 ``industrial-strength'', and ``next-generation'', and avoid superlatives
19617 like ``the most advanced''---they are not helpful to users looking for a
19618 package and may even sound suspicious. Instead, try to be factual,
19619 mentioning use cases and features.
19621 @cindex Texinfo markup, in package descriptions
19622 Descriptions can include Texinfo markup, which is useful to introduce
19623 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
19624 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
19625 should be careful when using some characters for example @samp{@@} and
19626 curly braces which are the basic special characters in Texinfo
19627 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
19628 such as @command{guix package --show} take care of rendering it
19631 Synopses and descriptions are translated by volunteers
19632 @uref{http://translationproject.org/domain/guix-packages.html, at the
19633 Translation Project} so that as many users as possible can read them in
19634 their native language. User interfaces search them and display them in
19635 the language specified by the current locale.
19637 To allow @command{xgettext} to extract them as translatable strings,
19638 synopses and descriptions @emph{must be literal strings}. This means
19639 that you cannot use @code{string-append} or @code{format} to construct
19645 (synopsis "This is translatable")
19646 (description (string-append "This is " "*not*" " translatable.")))
19649 Translation is a lot of work so, as a packager, please pay even more
19650 attention to your synopses and descriptions as every change may entail
19651 additional work for translators. In order to help them, it is possible
19652 to make recommendations or instructions visible to them by inserting
19653 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
19657 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
19658 (description "ARandR is designed to provide a simple visual front end
19659 for the X11 resize-and-rotate (RandR) extension. @dots{}")
19663 @node Python Modules
19664 @subsection Python Modules
19667 We currently package Python 2 and Python 3, under the Scheme variable names
19668 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
19669 To avoid confusion and naming clashes with other programming languages, it
19670 seems desirable that the name of a package for a Python module contains
19671 the word @code{python}.
19673 Some modules are compatible with only one version of Python, others with both.
19674 If the package Foo compiles only with Python 3, we name it
19675 @code{python-foo}; if it compiles only with Python 2, we name it
19676 @code{python2-foo}. If it is compatible with both versions, we create two
19677 packages with the corresponding names.
19679 If a project already contains the word @code{python}, we drop this;
19680 for instance, the module python-dateutil is packaged under the names
19681 @code{python-dateutil} and @code{python2-dateutil}. If the project name
19682 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
19685 @subsubsection Specifying Dependencies
19686 @cindex inputs, for Python packages
19688 Dependency information for Python packages is usually available in the
19689 package source tree, with varying degrees of accuracy: in the
19690 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
19692 Your mission, when writing a recipe for a Python package, is to map
19693 these dependencies to the appropriate type of ``input'' (@pxref{package
19694 Reference, inputs}). Although the @code{pypi} importer normally does a
19695 good job (@pxref{Invoking guix import}), you may want to check the
19696 following check list to determine which dependency goes where.
19701 We currently package Python 2 with @code{setuptools} and @code{pip}
19702 installed like Python 3.4 has per default. Thus you don't need to
19703 specify either of these as an input. @command{guix lint} will warn you
19707 Python dependencies required at run time go into
19708 @code{propagated-inputs}. They are typically defined with the
19709 @code{install_requires} keyword in @file{setup.py}, or in the
19710 @file{requirements.txt} file.
19713 Python packages required only at build time---e.g., those listed with
19714 the @code{setup_requires} keyword in @file{setup.py}---or only for
19715 testing---e.g., those in @code{tests_require}---go into
19716 @code{native-inputs}. The rationale is that (1) they do not need to be
19717 propagated because they are not needed at run time, and (2) in a
19718 cross-compilation context, it's the ``native'' input that we'd want.
19720 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
19721 frameworks. Of course if any of these packages is also required at
19722 run-time, it needs to go to @code{propagated-inputs}.
19725 Anything that does not fall in the previous categories goes to
19726 @code{inputs}, for example programs or C libraries required for building
19727 Python packages containing C extensions.
19730 If a Python package has optional dependencies (@code{extras_require}),
19731 it is up to you to decide whether to add them or not, based on their
19732 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
19739 @subsection Perl Modules
19742 Perl programs standing for themselves are named as any other package,
19743 using the lowercase upstream name.
19744 For Perl packages containing a single class, we use the lowercase class name,
19745 replace all occurrences of @code{::} by dashes and prepend the prefix
19747 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
19748 Modules containing several classes keep their lowercase upstream name and
19749 are also prepended by @code{perl-}. Such modules tend to have the word
19750 @code{perl} somewhere in their name, which gets dropped in favor of the
19751 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
19754 @node Java Packages
19755 @subsection Java Packages
19758 Java programs standing for themselves are named as any other package,
19759 using the lowercase upstream name.
19761 To avoid confusion and naming clashes with other programming languages,
19762 it is desirable that the name of a package for a Java package is
19763 prefixed with @code{java-}. If a project already contains the word
19764 @code{java}, we drop this; for instance, the package @code{ngsjava} is
19765 packaged under the name @code{java-ngs}.
19767 For Java packages containing a single class or a small class hierarchy,
19768 we use the lowercase class name, replace all occurrences of @code{.} by
19769 dashes and prepend the prefix @code{java-}. So the class
19770 @code{apache.commons.cli} becomes package
19771 @code{java-apache-commons-cli}.
19778 For fonts that are in general not installed by a user for typesetting
19779 purposes, or that are distributed as part of a larger software package,
19780 we rely on the general packaging rules for software; for instance, this
19781 applies to the fonts delivered as part of the X.Org system or fonts that
19782 are part of TeX Live.
19784 To make it easier for a user to search for fonts, names for other packages
19785 containing only fonts are constructed as follows, independently of the
19786 upstream package name.
19788 The name of a package containing only one font family starts with
19789 @code{font-}; it is followed by the foundry name and a dash @code{-}
19790 if the foundry is known, and the font family name, in which spaces are
19791 replaced by dashes (and as usual, all upper case letters are transformed
19793 For example, the Gentium font family by SIL is packaged under the name
19794 @code{font-sil-gentium}.
19796 For a package containing several font families, the name of the collection
19797 is used in the place of the font family name.
19798 For instance, the Liberation fonts consist of three families,
19799 Liberation Sans, Liberation Serif and Liberation Mono.
19800 These could be packaged separately under the names
19801 @code{font-liberation-sans} and so on; but as they are distributed together
19802 under a common name, we prefer to package them together as
19803 @code{font-liberation}.
19805 In the case where several formats of the same font family or font collection
19806 are packaged separately, a short form of the format, prepended by a dash,
19807 is added to the package name. We use @code{-ttf} for TrueType fonts,
19808 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
19813 @node Bootstrapping
19814 @section Bootstrapping
19816 @c Adapted from the ELS 2013 paper.
19818 @cindex bootstrapping
19820 Bootstrapping in our context refers to how the distribution gets built
19821 ``from nothing''. Remember that the build environment of a derivation
19822 contains nothing but its declared inputs (@pxref{Introduction}). So
19823 there's an obvious chicken-and-egg problem: how does the first package
19824 get built? How does the first compiler get compiled? Note that this is
19825 a question of interest only to the curious hacker, not to the regular
19826 user, so you can shamelessly skip this section if you consider yourself
19827 a ``regular user''.
19829 @cindex bootstrap binaries
19830 The GNU system is primarily made of C code, with libc at its core. The
19831 GNU build system itself assumes the availability of a Bourne shell and
19832 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
19833 `grep'. Furthermore, build programs---programs that run
19834 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
19835 (@pxref{Derivations}). Consequently, to be able to build anything at
19836 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
19837 Binutils, libc, and the other packages mentioned above---the
19838 @dfn{bootstrap binaries}.
19840 These bootstrap binaries are ``taken for granted'', though we can also
19841 re-create them if needed (more on that later).
19843 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
19845 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
19846 @c large image, it's hard to scroll. Oh well.
19847 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
19849 The figure above shows the very beginning of the dependency graph of the
19850 distribution, corresponding to the package definitions of the @code{(gnu
19851 packages bootstrap)} module. A similar figure can be generated with
19852 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
19855 guix graph -t derivation \
19856 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
19860 At this level of detail, things are
19861 slightly complex. First, Guile itself consists of an ELF executable,
19862 along with many source and compiled Scheme files that are dynamically
19863 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
19864 tarball shown in this graph. This tarball is part of Guix's ``source''
19865 distribution, and gets inserted into the store with @code{add-to-store}
19866 (@pxref{The Store}).
19868 But how do we write a derivation that unpacks this tarball and adds it
19869 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
19870 derivation---the first one that gets built---uses @code{bash} as its
19871 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
19872 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
19873 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
19874 the Guix source distribution, whose sole purpose is to allow the Guile
19875 tarball to be unpacked.
19877 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
19878 Guile that can be used to run subsequent build programs. Its first task
19879 is to download tarballs containing the other pre-built binaries---this
19880 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
19881 @code{ftp-client.scm} are used for this purpose. The
19882 @code{module-import.drv} derivations import those modules in a directory
19883 in the store, using the original layout. The
19884 @code{module-import-compiled.drv} derivations compile those modules, and
19885 write them in an output directory with the right layout. This
19886 corresponds to the @code{#:modules} argument of
19887 @code{build-expression->derivation} (@pxref{Derivations}).
19889 Finally, the various tarballs are unpacked by the
19890 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
19891 etc., at which point we have a working C tool chain.
19894 @unnumberedsubsec Building the Build Tools
19896 Bootstrapping is complete when we have a full tool chain that does not
19897 depend on the pre-built bootstrap tools discussed above. This
19898 no-dependency requirement is verified by checking whether the files of
19899 the final tool chain contain references to the @file{/gnu/store}
19900 directories of the bootstrap inputs. The process that leads to this
19901 ``final'' tool chain is described by the package definitions found in
19902 the @code{(gnu packages commencement)} module.
19904 The @command{guix graph} command allows us to ``zoom out'' compared to
19905 the graph above, by looking at the level of package objects instead of
19906 individual derivations---remember that a package may translate to
19907 several derivations, typically one derivation to download its source,
19908 one to build the Guile modules it needs, and one to actually build the
19909 package from source. The command:
19912 guix graph -t bag \
19913 -e '(@@@@ (gnu packages commencement)
19914 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
19918 produces the dependency graph leading to the ``final'' C
19919 library@footnote{You may notice the @code{glibc-intermediate} label,
19920 suggesting that it is not @emph{quite} final, but as a good
19921 approximation, we will consider it final.}, depicted below.
19923 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
19925 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
19926 The first tool that gets built with the bootstrap binaries is
19927 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
19928 for all the following packages. From there Findutils and Diffutils get
19931 Then come the first-stage Binutils and GCC, built as pseudo cross
19932 tools---i.e., with @code{--target} equal to @code{--host}. They are
19933 used to build libc. Thanks to this cross-build trick, this libc is
19934 guaranteed not to hold any reference to the initial tool chain.
19936 From there the final Binutils and GCC (not shown above) are built.
19938 from the final Binutils, and links programs against the just-built libc.
19939 This tool chain is used to build the other packages used by Guix and by
19940 the GNU Build System: Guile, Bash, Coreutils, etc.
19942 And voilà! At this point we have the complete set of build tools that
19943 the GNU Build System expects. These are in the @code{%final-inputs}
19944 variable of the @code{(gnu packages commencement)} module, and are
19945 implicitly used by any package that uses @code{gnu-build-system}
19946 (@pxref{Build Systems, @code{gnu-build-system}}).
19949 @unnumberedsubsec Building the Bootstrap Binaries
19951 @cindex bootstrap binaries
19952 Because the final tool chain does not depend on the bootstrap binaries,
19953 those rarely need to be updated. Nevertheless, it is useful to have an
19954 automated way to produce them, should an update occur, and this is what
19955 the @code{(gnu packages make-bootstrap)} module provides.
19957 The following command builds the tarballs containing the bootstrap
19958 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
19959 of Coreutils and other basic command-line tools):
19962 guix build bootstrap-tarballs
19965 The generated tarballs are those that should be referred to in the
19966 @code{(gnu packages bootstrap)} module mentioned at the beginning of
19969 Still here? Then perhaps by now you've started to wonder: when do we
19970 reach a fixed point? That is an interesting question! The answer is
19971 unknown, but if you would like to investigate further (and have
19972 significant computational and storage resources to do so), then let us
19976 @section Porting to a New Platform
19978 As discussed above, the GNU distribution is self-contained, and
19979 self-containment is achieved by relying on pre-built ``bootstrap
19980 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
19981 operating system kernel, CPU architecture, and application binary
19982 interface (ABI). Thus, to port the distribution to a platform that is
19983 not yet supported, one must build those bootstrap binaries, and update
19984 the @code{(gnu packages bootstrap)} module to use them on that platform.
19986 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
19987 When everything goes well, and assuming the GNU tool chain supports the
19988 target platform, this can be as simple as running a command like this
19992 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
19995 For this to work, the @code{glibc-dynamic-linker} procedure in
19996 @code{(gnu packages bootstrap)} must be augmented to return the right
19997 file name for libc's dynamic linker on that platform; likewise,
19998 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
19999 taught about the new platform.
20001 Once these are built, the @code{(gnu packages bootstrap)} module needs
20002 to be updated to refer to these binaries on the target platform. That
20003 is, the hashes and URLs of the bootstrap tarballs for the new platform
20004 must be added alongside those of the currently supported platforms. The
20005 bootstrap Guile tarball is treated specially: it is expected to be
20006 available locally, and @file{gnu/local.mk} has rules do download it for
20007 the supported architectures; a rule for the new platform must be added
20010 In practice, there may be some complications. First, it may be that the
20011 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
20012 above) is not recognized by all the GNU tools. Typically, glibc
20013 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
20014 configure flag (see @code{gcc.scm} for examples of how to handle this).
20015 Second, some of the required packages could fail to build for that
20016 platform. Lastly, the generated binaries could be broken for some
20019 @c *********************************************************************
20020 @include contributing.texi
20022 @c *********************************************************************
20023 @node Acknowledgments
20024 @chapter Acknowledgments
20026 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
20027 which was designed and
20028 implemented by Eelco Dolstra, with contributions from other people (see
20029 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
20030 management, and promoted unprecedented features, such as transactional
20031 package upgrades and rollbacks, per-user profiles, and referentially
20032 transparent build processes. Without this work, Guix would not exist.
20034 The Nix-based software distributions, Nixpkgs and NixOS, have also been
20035 an inspiration for Guix.
20037 GNU@tie{}Guix itself is a collective work with contributions from a
20038 number of people. See the @file{AUTHORS} file in Guix for more
20039 information on these fine people. The @file{THANKS} file lists people
20040 who have helped by reporting bugs, taking care of the infrastructure,
20041 providing artwork and themes, making suggestions, and more---thank you!
20044 @c *********************************************************************
20045 @node GNU Free Documentation License
20046 @appendix GNU Free Documentation License
20047 @cindex license, GNU Free Documentation License
20048 @include fdl-1.3.texi
20050 @c *********************************************************************
20051 @node Concept Index
20052 @unnumbered Concept Index
20055 @node Programming Index
20056 @unnumbered Programming Index
20057 @syncodeindex tp fn
20058 @syncodeindex vr fn
20063 @c Local Variables:
20064 @c ispell-local-dictionary: "american";