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 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
43 Permission is granted to copy, distribute and/or modify this document
44 under the terms of the GNU Free Documentation License, Version 1.3 or
45 any later version published by the Free Software Foundation; with no
46 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
47 copy of the license is included in the section entitled ``GNU Free
48 Documentation License''.
51 @dircategory System administration
53 * Guix: (guix). Manage installed software and system configuration.
54 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
55 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
56 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
57 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
60 @dircategory Software development
62 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
63 * guix build: (guix)Invoking guix build. Building packages.
64 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
68 @title GNU Guix Reference Manual
69 @subtitle Using the GNU Guix Functional Package Manager
70 @author The GNU Guix Developers
73 @vskip 0pt plus 1filll
74 Edition @value{EDITION} @*
82 @c *********************************************************************
86 This document describes GNU Guix version @value{VERSION}, a functional
87 package management tool written for the GNU system.
90 * Introduction:: What is Guix about?
91 * Installation:: Installing Guix.
92 * Package Management:: Package installation, upgrade, etc.
93 * Programming Interface:: Using Guix in Scheme.
94 * Utilities:: Package management commands.
95 * GNU Distribution:: Software for your friendly GNU system.
96 * Contributing:: Your help needed!
98 * Acknowledgments:: Thanks!
99 * GNU Free Documentation License:: The license of this manual.
100 * Concept Index:: Concepts.
101 * Programming Index:: Data types, functions, and variables.
104 --- The Detailed Node Listing ---
108 * Binary Installation:: Getting Guix running in no time!
109 * Requirements:: Software needed to build and run Guix.
110 * Running the Test Suite:: Testing Guix.
111 * Setting Up the Daemon:: Preparing the build daemon's environment.
112 * Invoking guix-daemon:: Running the build daemon.
113 * Application Setup:: Application-specific setup.
115 Setting Up the Daemon
117 * Build Environment Setup:: Preparing the isolated build environment.
118 * Daemon Offload Setup:: Offloading builds to remote machines.
122 * Features:: How Guix will make your life brighter.
123 * Invoking guix package:: Package installation, removal, etc.
124 * Substitutes:: Downloading pre-built binaries.
125 * Packages with Multiple Outputs:: Single source package, multiple outputs.
126 * Invoking guix gc:: Running the garbage collector.
127 * Invoking guix pull:: Fetching the latest Guix and distribution.
128 * Invoking guix pack:: Creating software bundles.
129 * Invoking guix archive:: Exporting and importing store files.
131 Programming Interface
133 * Defining Packages:: Defining new packages.
134 * Build Systems:: Specifying how packages are built.
135 * The Store:: Manipulating the package store.
136 * Derivations:: Low-level interface to package derivations.
137 * The Store Monad:: Purely functional interface to the store.
138 * G-Expressions:: Manipulating build expressions.
142 * package Reference :: The package data type.
143 * origin Reference:: The origin data type.
147 * Invoking guix build:: Building packages from the command line.
148 * Invoking guix edit:: Editing package definitions.
149 * Invoking guix download:: Downloading a file and printing its hash.
150 * Invoking guix hash:: Computing the cryptographic hash of a file.
151 * Invoking guix import:: Importing package definitions.
152 * Invoking guix refresh:: Updating package definitions.
153 * Invoking guix lint:: Finding errors in package definitions.
154 * Invoking guix size:: Profiling disk usage.
155 * Invoking guix graph:: Visualizing the graph of packages.
156 * Invoking guix environment:: Setting up development environments.
157 * Invoking guix publish:: Sharing substitutes.
158 * Invoking guix challenge:: Challenging substitute servers.
159 * Invoking guix copy:: Copying to and from a remote store.
160 * Invoking guix container:: Process isolation.
162 Invoking @command{guix build}
164 * Common Build Options:: Build options for most commands.
165 * Package Transformation Options:: Creating variants of packages.
166 * Additional Build Options:: Options specific to 'guix build'.
167 * Debugging Build Failures:: Real life packaging experience.
171 * System Installation:: Installing the whole operating system.
172 * System Configuration:: Configuring the operating system.
173 * Documentation:: Browsing software user manuals.
174 * Installing Debugging Files:: Feeding the debugger.
175 * Security Updates:: Deploying security fixes quickly.
176 * Package Modules:: Packages from the programmer's viewpoint.
177 * Packaging Guidelines:: Growing the distribution.
178 * Bootstrapping:: GNU/Linux built from scratch.
179 * Porting:: Targeting another platform or kernel.
183 * Limitations:: What you can expect.
184 * Hardware Considerations:: Supported hardware.
185 * USB Stick Installation:: Preparing the installation medium.
186 * Preparing for Installation:: Networking, partitioning, etc.
187 * Proceeding with the Installation:: The real thing.
188 * Installing GuixSD in a VM:: GuixSD playground.
189 * Building the Installation Image:: How this comes to be.
193 * Using the Configuration System:: Customizing your GNU system.
194 * operating-system Reference:: Detail of operating-system declarations.
195 * File Systems:: Configuring file system mounts.
196 * Mapped Devices:: Block device extra processing.
197 * User Accounts:: Specifying user accounts.
198 * Locales:: Language and cultural convention settings.
199 * Services:: Specifying system services.
200 * Setuid Programs:: Programs running with root privileges.
201 * X.509 Certificates:: Authenticating HTTPS servers.
202 * Name Service Switch:: Configuring libc's name service switch.
203 * Initial RAM Disk:: Linux-Libre bootstrapping.
204 * Bootloader Configuration:: Configuring the boot loader.
205 * Invoking guix system:: Instantiating a system configuration.
206 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
207 * Defining Services:: Adding new service definitions.
211 * Base Services:: Essential system services.
212 * Scheduled Job Execution:: The mcron service.
213 * Log Rotation:: The rottlog service.
214 * Networking Services:: Network setup, SSH daemon, etc.
215 * X Window:: Graphical display.
216 * Printing Services:: Local and remote printer support.
217 * Desktop Services:: D-Bus and desktop services.
218 * Database Services:: SQL databases.
219 * Mail Services:: IMAP, POP3, SMTP, and all that.
220 * Messaging Services:: Messaging services.
221 * Kerberos Services:: Kerberos services.
222 * Web Services:: Web servers.
223 * DNS Services:: DNS daemons.
224 * VPN Services:: VPN daemons.
225 * Network File System:: NFS related services.
226 * Continuous Integration:: The Cuirass service.
227 * Power management Services:: The TLP tool.
228 * Miscellaneous Services:: Other services.
232 * Service Composition:: The model for composing services.
233 * Service Types and Services:: Types and services.
234 * Service Reference:: API reference.
235 * Shepherd Services:: A particular type of service.
239 * Software Freedom:: What may go into the distribution.
240 * Package Naming:: What's in a name?
241 * Version Numbers:: When the name is not enough.
242 * Synopses and Descriptions:: Helping users find the right package.
243 * Python Modules:: A touch of British comedy.
244 * Perl Modules:: Little pearls.
245 * Java Packages:: Coffee break.
246 * Fonts:: Fond of fonts.
250 * Building from Git:: The latest and greatest.
251 * Running Guix Before It Is Installed:: Hacker tricks.
252 * The Perfect Setup:: The right tools.
253 * Coding Style:: Hygiene of the contributor.
254 * Submitting Patches:: Share your work.
258 * Programming Paradigm:: How to compose your elements.
259 * Modules:: Where to store your code?
260 * Data Types and Pattern Matching:: Implementing data structures.
261 * Formatting Code:: Writing conventions.
266 @c *********************************************************************
268 @chapter Introduction
271 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
272 using the international phonetic alphabet (IPA).} is a package
273 management tool for the GNU system. Guix makes it easy for unprivileged
274 users to install, upgrade, or remove packages, to roll back to a
275 previous package set, to build packages from source, and generally
276 assists with the creation and maintenance of software environments.
278 @cindex user interfaces
279 Guix provides a command-line package management interface
280 (@pxref{Invoking guix package}), a set of command-line utilities
281 (@pxref{Utilities}), as well as Scheme programming interfaces
282 (@pxref{Programming Interface}).
284 Its @dfn{build daemon} is responsible for building packages on behalf of
285 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
286 binaries from authorized sources (@pxref{Substitutes}).
288 @cindex extensibility of the distribution
289 @cindex customization, of packages
290 Guix includes package definitions for many GNU and non-GNU packages, all
291 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
292 user's computing freedom}. It is @emph{extensible}: users can write
293 their own package definitions (@pxref{Defining Packages}) and make them
294 available as independent package modules (@pxref{Package Modules}). It
295 is also @emph{customizable}: users can @emph{derive} specialized package
296 definitions from existing ones, including from the command line
297 (@pxref{Package Transformation Options}).
299 @cindex Guix System Distribution
301 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
302 where it complements the available tools without interference
303 (@pxref{Installation}), or you can use it as part of the standalone
304 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
305 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
306 system configuration and Guix takes care of instantiating the
307 configuration in a transactional, reproducible, and stateless fashion
308 (@pxref{System Configuration}).
310 @cindex functional package management
311 Under the hood, Guix implements the @dfn{functional package management}
312 discipline pioneered by Nix (@pxref{Acknowledgments}).
313 In Guix, the package build and installation process is seen
314 as a @emph{function}, in the mathematical sense. That function takes inputs,
315 such as build scripts, a compiler, and libraries, and
316 returns an installed package. As a pure function, its result depends
317 solely on its inputs---for instance, it cannot refer to software or
318 scripts that were not explicitly passed as inputs. A build function
319 always produces the same result when passed a given set of inputs. It
320 cannot alter the environment of the running system in
321 any way; for instance, it cannot create, modify, or delete files outside
322 of its build and installation directories. This is achieved by running
323 build processes in isolated environments (or @dfn{containers}), where only their
324 explicit inputs are visible.
327 The result of package build functions is @dfn{cached} in the file
328 system, in a special directory called @dfn{the store} (@pxref{The
329 Store}). Each package is installed in a directory of its own in the
330 store---by default under @file{/gnu/store}. The directory name contains
331 a hash of all the inputs used to build that package; thus, changing an
332 input yields a different directory name.
334 This approach is the foundation for the salient features of Guix: support
335 for transactional package upgrade and rollback, per-user installation, and
336 garbage collection of packages (@pxref{Features}).
339 @c *********************************************************************
341 @chapter Installation
343 @cindex installing Guix
344 GNU Guix is available for download from its website at
345 @url{http://www.gnu.org/software/guix/}. This section describes the
346 software requirements of Guix, as well as how to install it and get
349 Note that this section is concerned with the installation of the package
350 manager, which can be done on top of a running GNU/Linux system. If,
351 instead, you want to install the complete GNU operating system,
352 @pxref{System Installation}.
354 @cindex foreign distro
355 When installed on a running GNU/Linux system---thereafter called a
356 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
357 without interference. Its data lives exclusively in two directories,
358 usually @file{/gnu/store} and @file{/var/guix}; other files on your
359 system, such as @file{/etc}, are left untouched.
361 Once installed, Guix can be updated by running @command{guix pull}
362 (@pxref{Invoking guix pull}).
365 * Binary Installation:: Getting Guix running in no time!
366 * Requirements:: Software needed to build and run Guix.
367 * Running the Test Suite:: Testing Guix.
368 * Setting Up the Daemon:: Preparing the build daemon's environment.
369 * Invoking guix-daemon:: Running the build daemon.
370 * Application Setup:: Application-specific setup.
373 @node Binary Installation
374 @section Binary Installation
376 @cindex installing Guix from binaries
377 This section describes how to install Guix on an arbitrary system from a
378 self-contained tarball providing binaries for Guix and for all its
379 dependencies. This is often quicker than installing from source, which
380 is described in the next sections. The only requirement is to have
383 Installing goes along these lines:
387 @cindex downloading Guix binary
388 Download the binary tarball from
389 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
390 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
391 already running the kernel Linux, and so on.
393 @c The following is somewhat duplicated in ``System Installation''.
394 Make sure to download the associated @file{.sig} file and to verify the
395 authenticity of the tarball against it, along these lines:
398 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
399 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
402 If that command fails because you do not have the required public key,
403 then run this command to import it:
406 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
410 and rerun the @code{gpg --verify} command.
411 @c end authentication part
418 # tar --warning=no-timestamp -xf \
419 guix-binary-@value{VERSION}.@var{system}.tar.xz
420 # mv var/guix /var/ && mv gnu /
423 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
424 The latter contains a ready-to-use profile for @code{root} (see next
427 Do @emph{not} unpack the tarball on a working Guix system since that
428 would overwrite its own essential files.
430 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
431 not emit warnings about ``implausibly old time stamps'' (such
432 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
434 They stem from the fact that all the
435 files in the archive have their modification time set to zero (which
436 means January 1st, 1970.) This is done on purpose to make sure the
437 archive content is independent of its creation time, thus making it
441 Make @code{root}'s profile available under @file{~/.guix-profile}:
444 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
448 Source @file{etc/profile} to augment @code{PATH} and other relevant
449 environment variables:
452 # GUIX_PROFILE=$HOME/.guix-profile \
453 source $GUIX_PROFILE/etc/profile
457 Create the group and user accounts for build users as explained below
458 (@pxref{Build Environment Setup}).
461 Run the daemon, and set it to automatically start on boot.
463 If your host distro uses the systemd init system, this can be achieved
466 @c Versions of systemd that supported symlinked service files are not
467 @c yet widely deployed, so we should suggest that users copy the service
470 @c See this thread for more information:
471 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
474 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
476 # systemctl start guix-daemon && systemctl enable guix-daemon
479 If your host distro uses the Upstart init system:
482 # initctl reload-configuration
483 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
487 Otherwise, you can still start the daemon manually with:
490 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
494 Make the @command{guix} command available to other users on the machine,
498 # mkdir -p /usr/local/bin
500 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
503 It is also a good idea to make the Info version of this manual available
507 # mkdir -p /usr/local/share/info
508 # cd /usr/local/share/info
509 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
513 That way, assuming @file{/usr/local/share/info} is in the search path,
514 running @command{info guix} will open this manual (@pxref{Other Info
515 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
519 @cindex substitutes, authorization thereof
520 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
521 (@pxref{Substitutes}), authorize them:
524 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
528 Each user may need to perform a few additional steps to make their Guix
529 environment ready for use, @pxref{Application Setup}.
532 Voilà, the installation is complete!
534 You can confirm that Guix is working by installing a sample package into
538 # guix package -i hello
541 The @code{guix} package must remain available in @code{root}'s profile,
542 or it would become subject to garbage collection---in which case you
543 would find yourself badly handicapped by the lack of the @command{guix}
544 command. In other words, do not remove @code{guix} by running
545 @code{guix package -r guix}.
547 The binary installation tarball can be (re)produced and verified simply
548 by running the following command in the Guix source tree:
551 make guix-binary.@var{system}.tar.xz
555 ... which, in turn, runs:
558 guix pack -s @var{system} --localstatedir guix
561 @xref{Invoking guix pack}, for more info on this handy tool.
564 @section Requirements
566 This section lists requirements when building Guix from source. The
567 build procedure for Guix is the same as for other GNU software, and is
568 not covered here. Please see the files @file{README} and @file{INSTALL}
569 in the Guix source tree for additional details.
571 GNU Guix depends on the following packages:
574 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
575 later, including 2.2.x;
576 @item @url{http://gnupg.org/, GNU libgcrypt};
578 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
579 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
580 Guile,, gnutls-guile, GnuTLS-Guile});
581 @item @url{http://www.gnu.org/software/make/, GNU Make}.
584 The following dependencies are optional:
589 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
590 allow you to use the @command{guix import pypi} command (@pxref{Invoking
591 guix import}). It is of
592 interest primarily for developers and not for casual users.
595 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
596 Support for build offloading (@pxref{Daemon Offload Setup}) and
597 @command{guix copy} (@pxref{Invoking guix copy}) depends on
598 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
599 version 0.10.2 or later.
602 When @url{http://zlib.net, zlib} is available, @command{guix publish}
603 can compress build byproducts (@pxref{Invoking guix publish}).
606 Unless @code{--disable-daemon} was passed to @command{configure}, the
607 following packages are also needed:
610 @item @url{http://sqlite.org, SQLite 3};
611 @item @url{http://www.bzip.org, libbz2};
612 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
616 @cindex state directory
617 When configuring Guix on a system that already has a Guix installation,
618 be sure to specify the same state directory as the existing installation
619 using the @code{--localstatedir} option of the @command{configure}
620 script (@pxref{Directory Variables, @code{localstatedir},, standards,
621 GNU Coding Standards}). The @command{configure} script protects against
622 unintended misconfiguration of @var{localstatedir} so you do not
623 inadvertently corrupt your store (@pxref{The Store}).
625 @cindex Nix, compatibility
626 When a working installation of @url{http://nixos.org/nix/, the Nix package
627 manager} is available, you
628 can instead configure Guix with @code{--disable-daemon}. In that case,
629 Nix replaces the three dependencies above.
631 Guix is compatible with Nix, so it is possible to share the same store
632 between both. To do so, you must pass @command{configure} not only the
633 same @code{--with-store-dir} value, but also the same
634 @code{--localstatedir} value. The latter is essential because it
635 specifies where the database that stores metadata about the store is
636 located, among other things. The default values for Nix are
637 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
638 Note that @code{--disable-daemon} is not required if
639 your goal is to share the store with Nix.
641 @node Running the Test Suite
642 @section Running the Test Suite
645 After a successful @command{configure} and @code{make} run, it is a good
646 idea to run the test suite. It can help catch issues with the setup or
647 environment, or bugs in Guix itself---and really, reporting test
648 failures is a good way to help improve the software. To run the test
655 Test cases can run in parallel: you can use the @code{-j} option of
656 GNU@tie{}make to speed things up. The first run may take a few minutes
657 on a recent machine; subsequent runs will be faster because the store
658 that is created for test purposes will already have various things in
661 It is also possible to run a subset of the tests by defining the
662 @code{TESTS} makefile variable as in this example:
665 make check TESTS="tests/store.scm tests/cpio.scm"
668 By default, tests results are displayed at a file level. In order to
669 see the details of every individual test cases, it is possible to define
670 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
673 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
676 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
677 @file{test-suite.log} file. Please specify the Guix version being used
678 as well as version numbers of the dependencies (@pxref{Requirements}) in
681 Guix also comes with a whole-system test suite that tests complete
682 GuixSD operating system instances. It can only run on systems where
683 Guix is already installed, using:
690 or, again, by defining @code{TESTS} to select a subset of tests to run:
693 make check-system TESTS="basic mcron"
696 These system tests are defined in the @code{(gnu tests @dots{})}
697 modules. They work by running the operating systems under test with
698 lightweight instrumentation in a virtual machine (VM). They can be
699 computationally intensive or rather cheap, depending on whether
700 substitutes are available for their dependencies (@pxref{Substitutes}).
701 Some of them require a lot of storage space to hold VM images.
703 Again in case of test failures, please send @email{bug-guix@@gnu.org}
706 @node Setting Up the Daemon
707 @section Setting Up the Daemon
710 Operations such as building a package or running the garbage collector
711 are all performed by a specialized process, the @dfn{build daemon}, on
712 behalf of clients. Only the daemon may access the store and its
713 associated database. Thus, any operation that manipulates the store
714 goes through the daemon. For instance, command-line tools such as
715 @command{guix package} and @command{guix build} communicate with the
716 daemon (@i{via} remote procedure calls) to instruct it what to do.
718 The following sections explain how to prepare the build daemon's
719 environment. See also @ref{Substitutes}, for information on how to allow
720 the daemon to download pre-built binaries.
723 * Build Environment Setup:: Preparing the isolated build environment.
724 * Daemon Offload Setup:: Offloading builds to remote machines.
727 @node Build Environment Setup
728 @subsection Build Environment Setup
730 @cindex build environment
731 In a standard multi-user setup, Guix and its daemon---the
732 @command{guix-daemon} program---are installed by the system
733 administrator; @file{/gnu/store} is owned by @code{root} and
734 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
735 Guix tools to build packages or otherwise access the store, and the
736 daemon will do it on their behalf, ensuring that the store is kept in a
737 consistent state, and allowing built packages to be shared among users.
740 When @command{guix-daemon} runs as @code{root}, you may not want package
741 build processes themselves to run as @code{root} too, for obvious
742 security reasons. To avoid that, a special pool of @dfn{build users}
743 should be created for use by build processes started by the daemon.
744 These build users need not have a shell and a home directory: they will
745 just be used when the daemon drops @code{root} privileges in build
746 processes. Having several such users allows the daemon to launch
747 distinct build processes under separate UIDs, which guarantees that they
748 do not interfere with each other---an essential feature since builds are
749 regarded as pure functions (@pxref{Introduction}).
751 On a GNU/Linux system, a build user pool may be created like this (using
752 Bash syntax and the @code{shadow} commands):
754 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
755 @c for why `-G' is needed.
757 # groupadd --system guixbuild
758 # for i in `seq -w 1 10`;
760 useradd -g guixbuild -G guixbuild \
761 -d /var/empty -s `which nologin` \
762 -c "Guix build user $i" --system \
768 The number of build users determines how many build jobs may run in
769 parallel, as specified by the @option{--max-jobs} option
770 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
771 @command{guix system vm} and related commands, you may need to add the
772 build users to the @code{kvm} group so they can access @file{/dev/kvm},
773 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
774 (@pxref{Invoking guix system}).
776 The @code{guix-daemon} program may then be run as @code{root} with the
777 following command@footnote{If your machine uses the systemd init system,
778 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
779 file in @file{/etc/systemd/system} will ensure that
780 @command{guix-daemon} is automatically started. Similarly, if your
781 machine uses the Upstart init system, drop the
782 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
783 file in @file{/etc/init}.}:
786 # guix-daemon --build-users-group=guixbuild
791 This way, the daemon starts build processes in a chroot, under one of
792 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
793 environment contains nothing but:
795 @c Keep this list in sync with libstore/build.cc! -----------------------
798 a minimal @code{/dev} directory, created mostly independently from the
799 host @code{/dev}@footnote{``Mostly'', because while the set of files
800 that appear in the chroot's @code{/dev} is fixed, most of these files
801 can only be created if the host has them.};
804 the @code{/proc} directory; it only shows the processes of the container
805 since a separate PID name space is used;
808 @file{/etc/passwd} with an entry for the current user and an entry for
812 @file{/etc/group} with an entry for the user's group;
815 @file{/etc/hosts} with an entry that maps @code{localhost} to
819 a writable @file{/tmp} directory.
822 You can influence the directory where the daemon stores build trees
823 @i{via} the @code{TMPDIR} environment variable. However, the build tree
824 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
825 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
826 This way, the value of @code{TMPDIR} does not leak inside build
827 environments, which avoids discrepancies in cases where build processes
828 capture the name of their build tree.
831 The daemon also honors the @code{http_proxy} environment variable for
832 HTTP downloads it performs, be it for fixed-output derivations
833 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
835 If you are installing Guix as an unprivileged user, it is still possible
836 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
837 However, build processes will not be isolated from one another, and not
838 from the rest of the system. Thus, build processes may interfere with
839 each other, and may access programs, libraries, and other files
840 available on the system---making it much harder to view them as
841 @emph{pure} functions.
844 @node Daemon Offload Setup
845 @subsection Using the Offload Facility
849 When desired, the build daemon can @dfn{offload} derivation builds to
850 other machines running Guix, using the @code{offload} @dfn{build
851 hook}@footnote{This feature is available only when
852 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
854 feature is enabled, a list of user-specified build machines is read from
855 @file{/etc/guix/machines.scm}; every time a build is requested, for
856 instance via @code{guix build}, the daemon attempts to offload it to one
857 of the machines that satisfy the constraints of the derivation, in
858 particular its system type---e.g., @file{x86_64-linux}. Missing
859 prerequisites for the build are copied over SSH to the target machine,
860 which then proceeds with the build; upon success the output(s) of the
861 build are copied back to the initial machine.
863 The @file{/etc/guix/machines.scm} file typically looks like this:
867 (name "eightysix.example.org")
868 (system "x86_64-linux")
869 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
871 (speed 2.)) ;incredibly fast!
874 (name "meeps.example.org")
875 (system "mips64el-linux")
876 (host-key "ssh-rsa AAAAB3Nza@dots{}")
879 (string-append (getenv "HOME")
880 "/.ssh/identity-for-guix"))))
884 In the example above we specify a list of two build machines, one for
885 the @code{x86_64} architecture and one for the @code{mips64el}
888 In fact, this file is---not surprisingly!---a Scheme file that is
889 evaluated when the @code{offload} hook is started. Its return value
890 must be a list of @code{build-machine} objects. While this example
891 shows a fixed list of build machines, one could imagine, say, using
892 DNS-SD to return a list of potential build machines discovered in the
893 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
894 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
897 @deftp {Data Type} build-machine
898 This data type represents build machines to which the daemon may offload
899 builds. The important fields are:
904 The host name of the remote machine.
907 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
910 The user account to use when connecting to the remote machine over SSH.
911 Note that the SSH key pair must @emph{not} be passphrase-protected, to
912 allow non-interactive logins.
915 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
916 This is used to authenticate the machine when we connect to it. It is a
917 long string that looks like this:
920 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
923 If the machine is running the OpenSSH daemon, @command{sshd}, the host
924 key can be found in a file such as
925 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
927 If the machine is running the SSH daemon of GNU@tie{}lsh,
928 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
929 similar file. It can be converted to the OpenSSH format using
930 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
933 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
934 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
939 A number of optional fields may be specified:
943 @item @code{port} (default: @code{22})
944 Port number of SSH server on the machine.
946 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
947 The SSH private key file to use when connecting to the machine, in
950 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
951 @itemx @code{compression-level} (default: @code{3})
952 The SSH-level compression methods and compression level requested.
954 Note that offloading relies on SSH compression to reduce bandwidth usage
955 when transferring files to and from build machines.
957 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
958 File name of the Unix-domain socket @command{guix-daemon} is listening
961 @item @code{parallel-builds} (default: @code{1})
962 The number of builds that may run in parallel on the machine.
964 @item @code{speed} (default: @code{1.0})
965 A ``relative speed factor''. The offload scheduler will tend to prefer
966 machines with a higher speed factor.
968 @item @code{features} (default: @code{'()})
969 A list of strings denoting specific features supported by the machine.
970 An example is @code{"kvm"} for machines that have the KVM Linux modules
971 and corresponding hardware support. Derivations can request features by
972 name, and they will be scheduled on matching build machines.
977 The @code{guile} command must be in the search path on the build
978 machines. In addition, the Guix modules must be in
979 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
980 this is the case by running:
983 ssh build-machine guile -c "'(use-modules (guix config))'"
986 There is one last thing to do once @file{machines.scm} is in place. As
987 explained above, when offloading, files are transferred back and forth
988 between the machine stores. For this to work, you first need to
989 generate a key pair on each machine to allow the daemon to export signed
990 archives of files from the store (@pxref{Invoking guix archive}):
993 # guix archive --generate-key
997 Each build machine must authorize the key of the master machine so that
998 it accepts store items it receives from the master:
1001 # guix archive --authorize < master-public-key.txt
1005 Likewise, the master machine must authorize the key of each build machine.
1007 All the fuss with keys is here to express pairwise mutual trust
1008 relations between the master and the build machines. Concretely, when
1009 the master receives files from a build machine (and @i{vice versa}), its
1010 build daemon can make sure they are genuine, have not been tampered
1011 with, and that they are signed by an authorized key.
1013 @cindex offload test
1014 To test whether your setup is operational, run this command on the
1021 This will attempt to connect to each of the build machines specified in
1022 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1023 available on each machine, attempt to export to the machine and import
1024 from it, and report any error in the process.
1026 If you want to test a different machine file, just specify it on the
1030 # guix offload test machines-qualif.scm
1033 Last, you can test the subset of the machines whose name matches a
1034 regular expression like this:
1037 # guix offload test machines.scm '\.gnu\.org$'
1040 @node Invoking guix-daemon
1041 @section Invoking @command{guix-daemon}
1043 The @command{guix-daemon} program implements all the functionality to
1044 access the store. This includes launching build processes, running the
1045 garbage collector, querying the availability of a build result, etc. It
1046 is normally run as @code{root} like this:
1049 # guix-daemon --build-users-group=guixbuild
1053 For details on how to set it up, @pxref{Setting Up the Daemon}.
1056 @cindex container, build environment
1057 @cindex build environment
1058 @cindex reproducible builds
1059 By default, @command{guix-daemon} launches build processes under
1060 different UIDs, taken from the build group specified with
1061 @code{--build-users-group}. In addition, each build process is run in a
1062 chroot environment that only contains the subset of the store that the
1063 build process depends on, as specified by its derivation
1064 (@pxref{Programming Interface, derivation}), plus a set of specific
1065 system directories. By default, the latter contains @file{/dev} and
1066 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1067 @dfn{container}: in addition to having its own file system tree, it has
1068 a separate mount name space, its own PID name space, network name space,
1069 etc. This helps achieve reproducible builds (@pxref{Features}).
1071 When the daemon performs a build on behalf of the user, it creates a
1072 build directory under @file{/tmp} or under the directory specified by
1073 its @code{TMPDIR} environment variable; this directory is shared with
1074 the container for the duration of the build. Be aware that using a
1075 directory other than @file{/tmp} can affect build results---for example,
1076 with a longer directory name, a build process that uses Unix-domain
1077 sockets might hit the name length limitation for @code{sun_path}, which
1078 it would otherwise not hit.
1080 The build directory is automatically deleted upon completion, unless the
1081 build failed and the client specified @option{--keep-failed}
1082 (@pxref{Invoking guix build, @option{--keep-failed}}).
1084 The following command-line options are supported:
1087 @item --build-users-group=@var{group}
1088 Take users from @var{group} to run build processes (@pxref{Setting Up
1089 the Daemon, build users}).
1091 @item --no-substitutes
1093 Do not use substitutes for build products. That is, always build things
1094 locally instead of allowing downloads of pre-built binaries
1095 (@pxref{Substitutes}).
1097 By default substitutes are used, unless the client---such as the
1098 @command{guix package} command---is explicitly invoked with
1099 @code{--no-substitutes}.
1101 When the daemon runs with @code{--no-substitutes}, clients can still
1102 explicitly enable substitution @i{via} the @code{set-build-options}
1103 remote procedure call (@pxref{The Store}).
1105 @item --substitute-urls=@var{urls}
1106 @anchor{daemon-substitute-urls}
1107 Consider @var{urls} the default whitespace-separated list of substitute
1108 source URLs. When this option is omitted,
1109 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1110 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1112 This means that substitutes may be downloaded from @var{urls}, as long
1113 as they are signed by a trusted signature (@pxref{Substitutes}).
1116 @item --no-build-hook
1117 Do not use the @dfn{build hook}.
1119 The build hook is a helper program that the daemon can start and to
1120 which it submits build requests. This mechanism is used to offload
1121 builds to other machines (@pxref{Daemon Offload Setup}).
1123 @item --cache-failures
1124 Cache build failures. By default, only successful builds are cached.
1126 When this option is used, @command{guix gc --list-failures} can be used
1127 to query the set of store items marked as failed; @command{guix gc
1128 --clear-failures} removes store items from the set of cached failures.
1129 @xref{Invoking guix gc}.
1131 @item --cores=@var{n}
1133 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1136 The default value is @code{0}, but it may be overridden by clients, such
1137 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1140 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1141 in the build process, which can then use it to exploit internal
1142 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1144 @item --max-jobs=@var{n}
1146 Allow at most @var{n} build jobs in parallel. The default value is
1147 @code{1}. Setting it to @code{0} means that no builds will be performed
1148 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1149 Setup}), or simply fail.
1151 @item --max-silent-time=@var{seconds}
1152 When the build or substitution process remains silent for more than
1153 @var{seconds}, terminate it and report a build failure.
1155 The default value is @code{0}, which disables the timeout.
1157 The value specified here can be overridden by clients (@pxref{Common
1158 Build Options, @code{--max-silent-time}}).
1160 @item --timeout=@var{seconds}
1161 Likewise, when the build or substitution process lasts for more than
1162 @var{seconds}, terminate it and report a build failure.
1164 The default value is @code{0}, which disables the timeout.
1166 The value specified here can be overridden by clients (@pxref{Common
1167 Build Options, @code{--timeout}}).
1169 @item --rounds=@var{N}
1170 Build each derivation @var{n} times in a row, and raise an error if
1171 consecutive build results are not bit-for-bit identical. Note that this
1172 setting can be overridden by clients such as @command{guix build}
1173 (@pxref{Invoking guix build}).
1175 When used in conjunction with @option{--keep-failed}, the differing
1176 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1177 This makes it easy to look for differences between the two results.
1180 Produce debugging output.
1182 This is useful to debug daemon start-up issues, but then it may be
1183 overridden by clients, for example the @code{--verbosity} option of
1184 @command{guix build} (@pxref{Invoking guix build}).
1186 @item --chroot-directory=@var{dir}
1187 Add @var{dir} to the build chroot.
1189 Doing this may change the result of build processes---for instance if
1190 they use optional dependencies found in @var{dir} when it is available,
1191 and not otherwise. For that reason, it is not recommended to do so.
1192 Instead, make sure that each derivation declares all the inputs that it
1195 @item --disable-chroot
1196 Disable chroot builds.
1198 Using this option is not recommended since, again, it would allow build
1199 processes to gain access to undeclared dependencies. It is necessary,
1200 though, when @command{guix-daemon} is running under an unprivileged user
1203 @item --disable-log-compression
1204 Disable compression of the build logs.
1206 Unless @code{--lose-logs} is used, all the build logs are kept in the
1207 @var{localstatedir}. To save space, the daemon automatically compresses
1208 them with bzip2 by default. This option disables that.
1210 @item --disable-deduplication
1211 @cindex deduplication
1212 Disable automatic file ``deduplication'' in the store.
1214 By default, files added to the store are automatically ``deduplicated'':
1215 if a newly added file is identical to another one found in the store,
1216 the daemon makes the new file a hard link to the other file. This can
1217 noticeably reduce disk usage, at the expense of slightly increased
1218 input/output load at the end of a build process. This option disables
1221 @item --gc-keep-outputs[=yes|no]
1222 Tell whether the garbage collector (GC) must keep outputs of live
1225 When set to ``yes'', the GC will keep the outputs of any live derivation
1226 available in the store---the @code{.drv} files. The default is ``no'',
1227 meaning that derivation outputs are kept only if they are GC roots.
1229 @item --gc-keep-derivations[=yes|no]
1230 Tell whether the garbage collector (GC) must keep derivations
1231 corresponding to live outputs.
1233 When set to ``yes'', as is the case by default, the GC keeps
1234 derivations---i.e., @code{.drv} files---as long as at least one of their
1235 outputs is live. This allows users to keep track of the origins of
1236 items in their store. Setting it to ``no'' saves a bit of disk space.
1238 Note that when both @code{--gc-keep-derivations} and
1239 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1240 prerequisites (the sources, compiler, libraries, and other build-time
1241 tools) of live objects in the store, regardless of whether these
1242 prerequisites are live. This is convenient for developers since it
1243 saves rebuilds or downloads.
1245 @item --impersonate-linux-2.6
1246 On Linux-based systems, impersonate Linux 2.6. This means that the
1247 kernel's @code{uname} system call will report 2.6 as the release number.
1249 This might be helpful to build programs that (usually wrongfully) depend
1250 on the kernel version number.
1253 Do not keep build logs. By default they are kept under
1254 @code{@var{localstatedir}/guix/log}.
1256 @item --system=@var{system}
1257 Assume @var{system} as the current system type. By default it is the
1258 architecture/kernel pair found at configure time, such as
1259 @code{x86_64-linux}.
1261 @item --listen=@var{socket}
1262 Listen for connections on @var{socket}, the file name of a Unix-domain
1263 socket. The default socket is
1264 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1265 useful in exceptional circumstances, such as if you need to run several
1266 daemons on the same machine.
1270 @node Application Setup
1271 @section Application Setup
1273 @cindex foreign distro
1274 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1275 so-called @dfn{foreign distro}---a few additional steps are needed to
1276 get everything in place. Here are some of them.
1280 @anchor{locales-and-locpath}
1281 @cindex locales, when not on GuixSD
1283 @vindex GUIX_LOCPATH
1284 Packages installed @i{via} Guix will not use the locale data of the
1285 host system. Instead, you must first install one of the locale packages
1286 available with Guix and then define the @code{GUIX_LOCPATH} environment
1290 $ guix package -i glibc-locales
1291 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1294 Note that the @code{glibc-locales} package contains data for all the
1295 locales supported by the GNU@tie{}libc and weighs in at around
1296 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1297 limited to a few UTF-8 locales.
1299 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1300 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1301 Manual}). There are two important differences though:
1305 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1306 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1307 to make sure the programs of the foreign distro will not end up loading
1308 incompatible locale data.
1311 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1312 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1313 should your Guix profile contain a mixture of programs linked against
1314 different libc version, each libc version will only try to load locale
1315 data in the right format.
1318 This is important because the locale data format used by different libc
1319 versions may be incompatible.
1321 @subsection Name Service Switch
1323 @cindex name service switch, glibc
1324 @cindex NSS (name service switch), glibc
1325 @cindex nscd (name service caching daemon)
1326 @cindex name service caching daemon (nscd)
1327 When using Guix on a foreign distro, we @emph{strongly recommend} that
1328 the system run the GNU C library's @dfn{name service cache daemon},
1329 @command{nscd}, which should be listening on the
1330 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1331 installed with Guix may fail to look up host names or user accounts, or
1332 may even crash. The next paragraphs explain why.
1334 @cindex @file{nsswitch.conf}
1335 The GNU C library implements a @dfn{name service switch} (NSS), which is
1336 an extensible mechanism for ``name lookups'' in general: host name
1337 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1338 The GNU C Library Reference Manual}).
1340 @cindex Network information service (NIS)
1341 @cindex NIS (Network information service)
1342 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1343 lookup implementations: for example, the @code{nss-mdns} plugin allow
1344 resolution of @code{.local} host names, the @code{nis} plugin allows
1345 user account lookup using the Network information service (NIS), and so
1346 on. These extra ``lookup services'' are configured system-wide in
1347 @file{/etc/nsswitch.conf}, and all the programs running on the system
1348 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1351 When they perform a name lookup---for instance by calling the
1352 @code{getaddrinfo} function in C---applications first try to connect to
1353 the nscd; on success, nscd performs name lookups on their behalf. If
1354 the nscd is not running, then they perform the name lookup by
1355 themselves, by loading the name lookup services into their own address
1356 space and running it. These name lookup services---the
1357 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1358 the host system's C library, rather than from the C library the
1359 application is linked against (the C library coming from Guix).
1361 And this is where the problem is: if your application is linked against
1362 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1363 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1364 likely crash or have its name lookups fail unexpectedly.
1366 Running @command{nscd} on the system, among other advantages, eliminates
1367 this binary incompatibility problem because those @code{libnss_*.so}
1368 files are loaded in the @command{nscd} process, not in applications
1371 @subsection X11 Fonts
1374 The majority of graphical applications use Fontconfig to locate and
1375 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1376 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1377 by default. Thus, to allow graphical applications installed with Guix
1378 to display fonts, you have to install fonts with Guix as well.
1379 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1380 @code{font-gnu-freefont-ttf}.
1382 To display text written in Chinese languages, Japanese, or Korean in
1383 graphical applications, consider installing
1384 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1385 has multiple outputs, one per language family (@pxref{Packages with
1386 Multiple Outputs}). For instance, the following command installs fonts
1387 for Chinese languages:
1390 guix package -i font-adobe-source-han-sans:cn
1393 @cindex @code{xterm}
1394 Older programs such as @command{xterm} do not use Fontconfig and instead
1395 rely on server-side font rendering. Such programs require to specify a
1396 full name of a font using XLFD (X Logical Font Description), like this:
1399 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1402 To be able to use such full names for the TrueType fonts installed in
1403 your Guix profile, you need to extend the font path of the X server:
1406 xset +fp ~/.guix-profile/share/fonts/truetype
1409 @cindex @code{xlsfonts}
1410 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1411 to make sure your TrueType fonts are listed there.
1413 @subsection X.509 Certificates
1415 @cindex @code{nss-certs}
1416 The @code{nss-certs} package provides X.509 certificates, which allow
1417 programs to authenticate Web servers accessed over HTTPS.
1419 When using Guix on a foreign distro, you can install this package and
1420 define the relevant environment variables so that packages know where to
1421 look for certificates. @xref{X.509 Certificates}, for detailed
1424 @subsection Emacs Packages
1426 @cindex @code{emacs}
1427 When you install Emacs packages with Guix, the elisp files may be placed
1428 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1430 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1431 directory exists because potentially there may exist thousands of Emacs
1432 packages and storing all their files in a single directory may be not
1433 reliable (because of name conflicts). So we think using a separate
1434 directory for each package is a good idea. It is very similar to how
1435 the Emacs package system organizes the file structure (@pxref{Package
1436 Files,,, emacs, The GNU Emacs Manual}).
1438 By default, Emacs (installed with Guix) ``knows'' where these packages
1439 are placed, so you do not need to perform any configuration. If, for
1440 some reason, you want to avoid auto-loading Emacs packages installed
1441 with Guix, you can do so by running Emacs with @code{--no-site-file}
1442 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1444 @subsection The GCC toolchain
1449 Guix offers individual compiler packages such as @code{gcc} but if you
1450 are in need of a complete toolchain for compiling and linking source
1451 code what you really want is the @code{gcc-toolchain} package. This
1452 package provides a complete GCC toolchain for C/C++ development,
1453 including GCC itself, the GNU C Library (headers and binaries, plus
1454 debugging symbols in the @code{debug} output), Binutils, and a linker
1457 @cindex attempt to use impure library, error message
1459 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1460 passed to the linker, add corresponding @code{-rpath} arguments, and
1461 invoke the actual linker with this new set of arguments. By default,
1462 the linker wrapper refuses to link to libraries outside the store to
1463 ensure ``purity''. This can be annoying when using the toolchain to
1464 link with local libraries. To allow references to libraries outside the
1465 store you need to define the environment variable
1466 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1470 @c *********************************************************************
1471 @node Package Management
1472 @chapter Package Management
1475 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1476 remove software packages, without having to know about their build
1477 procedures or dependencies. Guix also goes beyond this obvious set of
1480 This chapter describes the main features of Guix, as well as the
1481 package management tools it provides. Along with the command-line
1482 interface described below (@pxref{Invoking guix package, @code{guix
1483 package}}), you may also use Emacs Interface (@pxref{Top,,,
1484 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1485 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1489 guix package -i emacs-guix
1493 * Features:: How Guix will make your life brighter.
1494 * Invoking guix package:: Package installation, removal, etc.
1495 * Substitutes:: Downloading pre-built binaries.
1496 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1497 * Invoking guix gc:: Running the garbage collector.
1498 * Invoking guix pull:: Fetching the latest Guix and distribution.
1499 * Invoking guix pack:: Creating software bundles.
1500 * Invoking guix archive:: Exporting and importing store files.
1506 When using Guix, each package ends up in the @dfn{package store}, in its
1507 own directory---something that resembles
1508 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1510 Instead of referring to these directories, users have their own
1511 @dfn{profile}, which points to the packages that they actually want to
1512 use. These profiles are stored within each user's home directory, at
1513 @code{$HOME/.guix-profile}.
1515 For example, @code{alice} installs GCC 4.7.2. As a result,
1516 @file{/home/alice/.guix-profile/bin/gcc} points to
1517 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1518 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1519 simply continues to point to
1520 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1521 coexist on the same system without any interference.
1523 The @command{guix package} command is the central tool to manage
1524 packages (@pxref{Invoking guix package}). It operates on the per-user
1525 profiles, and can be used @emph{with normal user privileges}.
1527 @cindex transactions
1528 The command provides the obvious install, remove, and upgrade
1529 operations. Each invocation is actually a @emph{transaction}: either
1530 the specified operation succeeds, or nothing happens. Thus, if the
1531 @command{guix package} process is terminated during the transaction,
1532 or if a power outage occurs during the transaction, then the user's
1533 profile remains in its previous state, and remains usable.
1535 In addition, any package transaction may be @emph{rolled back}. So, if,
1536 for example, an upgrade installs a new version of a package that turns
1537 out to have a serious bug, users may roll back to the previous instance
1538 of their profile, which was known to work well. Similarly, the global
1539 system configuration on GuixSD is subject to
1540 transactional upgrades and roll-back
1541 (@pxref{Using the Configuration System}).
1543 All packages in the package store may be @emph{garbage-collected}.
1544 Guix can determine which packages are still referenced by user
1545 profiles, and remove those that are provably no longer referenced
1546 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1547 generations of their profile so that the packages they refer to can be
1550 @cindex reproducibility
1551 @cindex reproducible builds
1552 Finally, Guix takes a @dfn{purely functional} approach to package
1553 management, as described in the introduction (@pxref{Introduction}).
1554 Each @file{/gnu/store} package directory name contains a hash of all the
1555 inputs that were used to build that package---compiler, libraries, build
1556 scripts, etc. This direct correspondence allows users to make sure a
1557 given package installation matches the current state of their
1558 distribution. It also helps maximize @dfn{build reproducibility}:
1559 thanks to the isolated build environments that are used, a given build
1560 is likely to yield bit-identical files when performed on different
1561 machines (@pxref{Invoking guix-daemon, container}).
1564 This foundation allows Guix to support @dfn{transparent binary/source
1565 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1566 available from an external source---a @dfn{substitute}, Guix just
1567 downloads it and unpacks it;
1568 otherwise, it builds the package from source, locally
1569 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1570 reproducible, users do not have to trust servers that provide
1571 substitutes: they can force a local build and @emph{challenge} providers
1572 (@pxref{Invoking guix challenge}).
1574 Control over the build environment is a feature that is also useful for
1575 developers. The @command{guix environment} command allows developers of
1576 a package to quickly set up the right development environment for their
1577 package, without having to manually install the dependencies of the
1578 package into their profile (@pxref{Invoking guix environment}).
1580 @node Invoking guix package
1581 @section Invoking @command{guix package}
1583 @cindex installing packages
1584 @cindex removing packages
1585 @cindex package installation
1586 @cindex package removal
1587 The @command{guix package} command is the tool that allows users to
1588 install, upgrade, and remove packages, as well as rolling back to
1589 previous configurations. It operates only on the user's own profile,
1590 and works with normal user privileges (@pxref{Features}). Its syntax
1594 guix package @var{options}
1596 @cindex transactions
1597 Primarily, @var{options} specifies the operations to be performed during
1598 the transaction. Upon completion, a new profile is created, but
1599 previous @dfn{generations} of the profile remain available, should the user
1602 For example, to remove @code{lua} and install @code{guile} and
1603 @code{guile-cairo} in a single transaction:
1606 guix package -r lua -i guile guile-cairo
1609 @command{guix package} also supports a @dfn{declarative approach}
1610 whereby the user specifies the exact set of packages to be available and
1611 passes it @i{via} the @option{--manifest} option
1612 (@pxref{profile-manifest, @option{--manifest}}).
1615 For each user, a symlink to the user's default profile is automatically
1616 created in @file{$HOME/.guix-profile}. This symlink always points to the
1617 current generation of the user's default profile. Thus, users can add
1618 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1619 variable, and so on.
1620 @cindex search paths
1621 If you are not using the Guix System Distribution, consider adding the
1622 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1623 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1624 shells get all the right environment variable definitions:
1627 GUIX_PROFILE="$HOME/.guix-profile" \
1628 source "$HOME/.guix-profile/etc/profile"
1631 In a multi-user setup, user profiles are stored in a place registered as
1632 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1633 to (@pxref{Invoking guix gc}). That directory is normally
1634 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1635 @var{localstatedir} is the value passed to @code{configure} as
1636 @code{--localstatedir}, and @var{user} is the user name. The
1637 @file{per-user} directory is created when @command{guix-daemon} is
1638 started, and the @var{user} sub-directory is created by @command{guix
1641 The @var{options} can be among the following:
1645 @item --install=@var{package} @dots{}
1646 @itemx -i @var{package} @dots{}
1647 Install the specified @var{package}s.
1649 Each @var{package} may specify either a simple package name, such as
1650 @code{guile}, or a package name followed by an at-sign and version number,
1651 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1652 case, the newest version prefixed by @code{1.8} is selected.)
1654 If no version number is specified, the
1655 newest available version will be selected. In addition, @var{package}
1656 may contain a colon, followed by the name of one of the outputs of the
1657 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1658 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1659 name (and optionally version) are searched for among the GNU
1660 distribution modules (@pxref{Package Modules}).
1662 @cindex propagated inputs
1663 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1664 that automatically get installed along with the required package
1665 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1666 @code{package} objects}, for information about propagated inputs in
1667 package definitions).
1669 @anchor{package-cmd-propagated-inputs}
1670 An example is the GNU MPC library: its C header files refer to those of
1671 the GNU MPFR library, which in turn refer to those of the GMP library.
1672 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1673 in the profile; removing MPC also removes MPFR and GMP---unless they had
1674 also been explicitly installed by the user.
1676 Besides, packages sometimes rely on the definition of environment
1677 variables for their search paths (see explanation of
1678 @code{--search-paths} below). Any missing or possibly incorrect
1679 environment variable definitions are reported here.
1681 @item --install-from-expression=@var{exp}
1683 Install the package @var{exp} evaluates to.
1685 @var{exp} must be a Scheme expression that evaluates to a
1686 @code{<package>} object. This option is notably useful to disambiguate
1687 between same-named variants of a package, with expressions such as
1688 @code{(@@ (gnu packages base) guile-final)}.
1690 Note that this option installs the first output of the specified
1691 package, which may be insufficient when needing a specific output of a
1692 multiple-output package.
1694 @item --install-from-file=@var{file}
1695 @itemx -f @var{file}
1696 Install the package that the code within @var{file} evaluates to.
1698 As an example, @var{file} might contain a definition like this
1699 (@pxref{Defining Packages}):
1702 @verbatiminclude package-hello.scm
1705 Developers may find it useful to include such a @file{guix.scm} file
1706 in the root of their project source tree that can be used to test
1707 development snapshots and create reproducible development environments
1708 (@pxref{Invoking guix environment}).
1710 @item --remove=@var{package} @dots{}
1711 @itemx -r @var{package} @dots{}
1712 Remove the specified @var{package}s.
1714 As for @code{--install}, each @var{package} may specify a version number
1715 and/or output name in addition to the package name. For instance,
1716 @code{-r glibc:debug} would remove the @code{debug} output of
1719 @item --upgrade[=@var{regexp} @dots{}]
1720 @itemx -u [@var{regexp} @dots{}]
1721 @cindex upgrading packages
1722 Upgrade all the installed packages. If one or more @var{regexp}s are
1723 specified, upgrade only installed packages whose name matches a
1724 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1726 Note that this upgrades package to the latest version of packages found
1727 in the distribution currently installed. To update your distribution,
1728 you should regularly run @command{guix pull} (@pxref{Invoking guix
1731 @item --do-not-upgrade[=@var{regexp} @dots{}]
1732 When used together with the @code{--upgrade} option, do @emph{not}
1733 upgrade any packages whose name matches a @var{regexp}. For example, to
1734 upgrade all packages in the current profile except those containing the
1735 substring ``emacs'':
1738 $ guix package --upgrade . --do-not-upgrade emacs
1741 @item @anchor{profile-manifest}--manifest=@var{file}
1742 @itemx -m @var{file}
1743 @cindex profile declaration
1744 @cindex profile manifest
1745 Create a new generation of the profile from the manifest object
1746 returned by the Scheme code in @var{file}.
1748 This allows you to @emph{declare} the profile's contents rather than
1749 constructing it through a sequence of @code{--install} and similar
1750 commands. The advantage is that @var{file} can be put under version
1751 control, copied to different machines to reproduce the same profile, and
1754 @c FIXME: Add reference to (guix profile) documentation when available.
1755 @var{file} must return a @dfn{manifest} object, which is roughly a list
1758 @findex packages->manifest
1760 (use-package-modules guile emacs)
1765 ;; Use a specific package output.
1766 (list guile-2.0 "debug")))
1769 @findex specifications->manifest
1770 In this example we have to know which modules define the @code{emacs}
1771 and @code{guile-2.0} variables to provide the right
1772 @code{use-package-modules} line, which can be cumbersome. We can
1773 instead provide regular package specifications and let
1774 @code{specifications->manifest} look up the corresponding package
1778 (specifications->manifest
1779 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1783 @cindex rolling back
1784 @cindex undoing transactions
1785 @cindex transactions, undoing
1786 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1787 the last transaction.
1789 When combined with options such as @code{--install}, roll back occurs
1790 before any other actions.
1792 When rolling back from the first generation that actually contains
1793 installed packages, the profile is made to point to the @dfn{zeroth
1794 generation}, which contains no files apart from its own metadata.
1796 After having rolled back, installing, removing, or upgrading packages
1797 overwrites previous future generations. Thus, the history of the
1798 generations in a profile is always linear.
1800 @item --switch-generation=@var{pattern}
1801 @itemx -S @var{pattern}
1803 Switch to a particular generation defined by @var{pattern}.
1805 @var{pattern} may be either a generation number or a number prefixed
1806 with ``+'' or ``-''. The latter means: move forward/backward by a
1807 specified number of generations. For example, if you want to return to
1808 the latest generation after @code{--roll-back}, use
1809 @code{--switch-generation=+1}.
1811 The difference between @code{--roll-back} and
1812 @code{--switch-generation=-1} is that @code{--switch-generation} will
1813 not make a zeroth generation, so if a specified generation does not
1814 exist, the current generation will not be changed.
1816 @item --search-paths[=@var{kind}]
1817 @cindex search paths
1818 Report environment variable definitions, in Bash syntax, that may be
1819 needed in order to use the set of installed packages. These environment
1820 variables are used to specify @dfn{search paths} for files used by some
1821 of the installed packages.
1823 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1824 environment variables to be defined so it can look for headers and
1825 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1826 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1827 library are installed in the profile, then @code{--search-paths} will
1828 suggest setting these variables to @code{@var{profile}/include} and
1829 @code{@var{profile}/lib}, respectively.
1831 The typical use case is to define these environment variables in the
1835 $ eval `guix package --search-paths`
1838 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1839 meaning that the returned environment variable definitions will either
1840 be exact settings, or prefixes or suffixes of the current value of these
1841 variables. When omitted, @var{kind} defaults to @code{exact}.
1843 This option can also be used to compute the @emph{combined} search paths
1844 of several profiles. Consider this example:
1847 $ guix package -p foo -i guile
1848 $ guix package -p bar -i guile-json
1849 $ guix package -p foo -p bar --search-paths
1852 The last command above reports about the @code{GUILE_LOAD_PATH}
1853 variable, even though, taken individually, neither @file{foo} nor
1854 @file{bar} would lead to that recommendation.
1857 @item --profile=@var{profile}
1858 @itemx -p @var{profile}
1859 Use @var{profile} instead of the user's default profile.
1862 Produce verbose output. In particular, emit the build log of the
1863 environment on the standard error port.
1866 Use the bootstrap Guile to build the profile. This option is only
1867 useful to distribution developers.
1871 In addition to these actions, @command{guix package} supports the
1872 following options to query the current state of a profile, or the
1873 availability of packages:
1877 @item --search=@var{regexp}
1878 @itemx -s @var{regexp}
1879 @cindex searching for packages
1880 List the available packages whose name, synopsis, or description matches
1881 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1882 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1883 GNU recutils manual}).
1885 This allows specific fields to be extracted using the @command{recsel}
1886 command, for instance:
1889 $ guix package -s malloc | recsel -p name,version,relevance
1903 Similarly, to show the name of all the packages available under the
1904 terms of the GNU@tie{}LGPL version 3:
1907 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1914 It is also possible to refine search results using several @code{-s}
1915 flags. For example, the following command returns a list of board
1919 $ guix package -s '\<board\>' -s game | recsel -p name
1924 If we were to omit @code{-s game}, we would also get software packages
1925 that deal with printed circuit boards; removing the angle brackets
1926 around @code{board} would further add packages that have to do with
1929 And now for a more elaborate example. The following command searches
1930 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1931 libraries, and prints the name and synopsis of the matching packages:
1934 $ guix package -s crypto -s library | \
1935 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1939 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1940 information on @dfn{selection expressions} for @code{recsel -e}.
1942 @item --show=@var{package}
1943 Show details about @var{package}, taken from the list of available packages, in
1944 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1948 $ guix package --show=python | recsel -p name,version
1956 You may also specify the full name of a package to only get details about a
1957 specific version of it:
1959 $ guix package --show=python@@3.4 | recsel -p name,version
1966 @item --list-installed[=@var{regexp}]
1967 @itemx -I [@var{regexp}]
1968 List the currently installed packages in the specified profile, with the
1969 most recently installed packages shown last. When @var{regexp} is
1970 specified, list only installed packages whose name matches @var{regexp}.
1972 For each installed package, print the following items, separated by
1973 tabs: the package name, its version string, the part of the package that
1974 is installed (for instance, @code{out} for the default output,
1975 @code{include} for its headers, etc.), and the path of this package in
1978 @item --list-available[=@var{regexp}]
1979 @itemx -A [@var{regexp}]
1980 List packages currently available in the distribution for this system
1981 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1982 installed packages whose name matches @var{regexp}.
1984 For each package, print the following items separated by tabs: its name,
1985 its version string, the parts of the package (@pxref{Packages with
1986 Multiple Outputs}), and the source location of its definition.
1988 @item --list-generations[=@var{pattern}]
1989 @itemx -l [@var{pattern}]
1991 Return a list of generations along with their creation dates; for each
1992 generation, show the installed packages, with the most recently
1993 installed packages shown last. Note that the zeroth generation is never
1996 For each installed package, print the following items, separated by
1997 tabs: the name of a package, its version string, the part of the package
1998 that is installed (@pxref{Packages with Multiple Outputs}), and the
1999 location of this package in the store.
2001 When @var{pattern} is used, the command returns only matching
2002 generations. Valid patterns include:
2005 @item @emph{Integers and comma-separated integers}. Both patterns denote
2006 generation numbers. For instance, @code{--list-generations=1} returns
2009 And @code{--list-generations=1,8,2} outputs three generations in the
2010 specified order. Neither spaces nor trailing commas are allowed.
2012 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2013 specified generations and everything in between. Note that the start of
2014 a range must be smaller than its end.
2016 It is also possible to omit the endpoint. For example,
2017 @code{--list-generations=2..}, returns all generations starting from the
2020 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2021 or months by passing an integer along with the first letter of the
2022 duration. For example, @code{--list-generations=20d} lists generations
2023 that are up to 20 days old.
2026 @item --delete-generations[=@var{pattern}]
2027 @itemx -d [@var{pattern}]
2028 When @var{pattern} is omitted, delete all generations except the current
2031 This command accepts the same patterns as @option{--list-generations}.
2032 When @var{pattern} is specified, delete the matching generations. When
2033 @var{pattern} specifies a duration, generations @emph{older} than the
2034 specified duration match. For instance, @code{--delete-generations=1m}
2035 deletes generations that are more than one month old.
2037 If the current generation matches, it is @emph{not} deleted. Also, the
2038 zeroth generation is never deleted.
2040 Note that deleting generations prevents rolling back to them.
2041 Consequently, this command must be used with care.
2045 Finally, since @command{guix package} may actually start build
2046 processes, it supports all the common build options (@pxref{Common Build
2047 Options}). It also supports package transformation options, such as
2048 @option{--with-source} (@pxref{Package Transformation Options}).
2049 However, note that package transformations are lost when upgrading; to
2050 preserve transformations across upgrades, you should define your own
2051 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2052 (@pxref{Defining Packages}).
2056 @section Substitutes
2059 @cindex pre-built binaries
2060 Guix supports transparent source/binary deployment, which means that it
2061 can either build things locally, or download pre-built items from a
2062 server. We call these pre-built items @dfn{substitutes}---they are
2063 substitutes for local build results. In many cases, downloading a
2064 substitute is much faster than building things locally.
2066 Substitutes can be anything resulting from a derivation build
2067 (@pxref{Derivations}). Of course, in the common case, they are
2068 pre-built package binaries, but source tarballs, for instance, which
2069 also result from derivation builds, can be available as substitutes.
2071 The @code{hydra.gnu.org} server is a front-end to a build farm that
2072 builds packages from the GNU distribution continuously for some
2073 architectures, and makes them available as substitutes. This is the
2074 default source of substitutes; it can be overridden by passing the
2075 @option{--substitute-urls} option either to @command{guix-daemon}
2076 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2077 or to client tools such as @command{guix package}
2078 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2081 Substitute URLs can be either HTTP or HTTPS.
2082 HTTPS is recommended because communications are encrypted; conversely,
2083 using HTTP makes all communications visible to an eavesdropper, who
2084 could use the information gathered to determine, for instance, whether
2085 your system has unpatched security vulnerabilities.
2088 @cindex digital signatures
2089 @cindex substitutes, authorization thereof
2090 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2092 must add its public key to the access control list (ACL) of archive
2093 imports, using the @command{guix archive} command (@pxref{Invoking guix
2094 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2095 be compromised and to serve genuine substitutes.
2097 This public key is installed along with Guix, in
2098 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2099 the installation prefix of Guix. If you installed Guix from source,
2100 make sure you checked the GPG signature of
2101 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2102 Then, you can run something like this:
2105 # guix archive --authorize < hydra.gnu.org.pub
2108 Once this is in place, the output of a command like @code{guix build}
2109 should change from something like:
2112 $ guix build emacs --dry-run
2113 The following derivations would be built:
2114 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2115 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2116 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2117 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2125 $ guix build emacs --dry-run
2126 The following files would be downloaded:
2127 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2128 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2129 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2130 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2135 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2136 will be downloaded, when possible, for future builds.
2138 Guix ignores substitutes that are not signed, or that are not signed by
2139 one of the keys listed in the ACL. It also detects and raises an error
2140 when attempting to use a substitute that has been tampered with.
2143 Substitutes are downloaded over HTTP or HTTPS.
2144 The @code{http_proxy} environment
2145 variable can be set in the environment of @command{guix-daemon} and is
2146 honored for downloads of substitutes. Note that the value of
2147 @code{http_proxy} in the environment where @command{guix build},
2148 @command{guix package}, and other client commands are run has
2149 @emph{absolutely no effect}.
2151 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2152 (in other words, the server is not authenticated), contrary to what
2153 HTTPS clients such as Web browsers usually do. This is because Guix
2154 authenticates substitute information itself, as explained above, which
2155 is what we care about (whereas X.509 certificates are about
2156 authenticating bindings between domain names and public keys.)
2158 The substitute mechanism can be disabled globally by running
2159 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2160 guix-daemon}). It can also be disabled temporarily by passing the
2161 @code{--no-substitutes} option to @command{guix package}, @command{guix
2162 build}, and other command-line tools.
2165 @unnumberedsubsec On Trusting Binaries
2167 Today, each individual's control over their own computing is at the
2168 mercy of institutions, corporations, and groups with enough power and
2169 determination to subvert the computing infrastructure and exploit its
2170 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2171 convenient, we encourage users to also build on their own, or even run
2172 their own build farm, such that @code{hydra.gnu.org} is less of an
2173 interesting target. One way to help is by publishing the software you
2174 build using @command{guix publish} so that others have one more choice
2175 of server to download substitutes from (@pxref{Invoking guix publish}).
2177 Guix has the foundations to maximize build reproducibility
2178 (@pxref{Features}). In most cases, independent builds of a given
2179 package or derivation should yield bit-identical results. Thus, through
2180 a diverse set of independent package builds, we can strengthen the
2181 integrity of our systems. The @command{guix challenge} command aims to
2182 help users assess substitute servers, and to assist developers in
2183 finding out about non-deterministic package builds (@pxref{Invoking guix
2184 challenge}). Similarly, the @option{--check} option of @command{guix
2185 build} allows users to check whether previously-installed substitutes
2186 are genuine by rebuilding them locally (@pxref{build-check,
2187 @command{guix build --check}}).
2189 In the future, we want Guix to have support to publish and retrieve
2190 binaries to/from other users, in a peer-to-peer fashion. If you would
2191 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2194 @node Packages with Multiple Outputs
2195 @section Packages with Multiple Outputs
2197 @cindex multiple-output packages
2198 @cindex package outputs
2201 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2202 source package leads to exactly one directory in the store. When running
2203 @command{guix package -i glibc}, one installs the default output of the
2204 GNU libc package; the default output is called @code{out}, but its name
2205 can be omitted as shown in this command. In this particular case, the
2206 default output of @code{glibc} contains all the C header files, shared
2207 libraries, static libraries, Info documentation, and other supporting
2210 Sometimes it is more appropriate to separate the various types of files
2211 produced from a single source package into separate outputs. For
2212 instance, the GLib C library (used by GTK+ and related packages)
2213 installs more than 20 MiB of reference documentation as HTML pages.
2214 To save space for users who do not need it, the documentation goes to a
2215 separate output, called @code{doc}. To install the main GLib output,
2216 which contains everything but the documentation, one would run:
2219 guix package -i glib
2222 @cindex documentation
2223 The command to install its documentation is:
2226 guix package -i glib:doc
2229 Some packages install programs with different ``dependency footprints''.
2230 For instance, the WordNet package installs both command-line tools and
2231 graphical user interfaces (GUIs). The former depend solely on the C
2232 library, whereas the latter depend on Tcl/Tk and the underlying X
2233 libraries. In this case, we leave the command-line tools in the default
2234 output, whereas the GUIs are in a separate output. This allows users
2235 who do not need the GUIs to save space. The @command{guix size} command
2236 can help find out about such situations (@pxref{Invoking guix size}).
2237 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2239 There are several such multiple-output packages in the GNU distribution.
2240 Other conventional output names include @code{lib} for libraries and
2241 possibly header files, @code{bin} for stand-alone programs, and
2242 @code{debug} for debugging information (@pxref{Installing Debugging
2243 Files}). The outputs of a packages are listed in the third column of
2244 the output of @command{guix package --list-available} (@pxref{Invoking
2248 @node Invoking guix gc
2249 @section Invoking @command{guix gc}
2251 @cindex garbage collector
2253 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2254 The @command{guix gc} command allows users to explicitly run the garbage
2255 collector to reclaim space from the @file{/gnu/store} directory. It is
2256 the @emph{only} way to remove files from @file{/gnu/store}---removing
2257 files or directories manually may break it beyond repair!
2259 The garbage collector has a set of known @dfn{roots}: any file under
2260 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2261 cannot be deleted; any other file is considered @dfn{dead} and may be
2262 deleted. The set of garbage collector roots includes default user
2263 profiles, and may be augmented with @command{guix build --root}, for
2264 example (@pxref{Invoking guix build}).
2266 Prior to running @code{guix gc --collect-garbage} to make space, it is
2267 often useful to remove old generations from user profiles; that way, old
2268 package builds referenced by those generations can be reclaimed. This
2269 is achieved by running @code{guix package --delete-generations}
2270 (@pxref{Invoking guix package}).
2272 The @command{guix gc} command has three modes of operation: it can be
2273 used to garbage-collect any dead files (the default), to delete specific
2274 files (the @code{--delete} option), to print garbage-collector
2275 information, or for more advanced queries. The garbage collection
2276 options are as follows:
2279 @item --collect-garbage[=@var{min}]
2280 @itemx -C [@var{min}]
2281 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2282 sub-directories. This is the default operation when no option is
2285 When @var{min} is given, stop once @var{min} bytes have been collected.
2286 @var{min} may be a number of bytes, or it may include a unit as a
2287 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2288 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2290 When @var{min} is omitted, collect all the garbage.
2292 @item --free-space=@var{free}
2293 @itemx -F @var{free}
2294 Collect garbage until @var{free} space is available under
2295 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2296 as @code{500MiB}, as described above.
2298 When @var{free} or more is already available in @file{/gnu/store}, do
2299 nothing and exit immediately.
2303 Attempt to delete all the store files and directories specified as
2304 arguments. This fails if some of the files are not in the store, or if
2305 they are still live.
2307 @item --list-failures
2308 List store items corresponding to cached build failures.
2310 This prints nothing unless the daemon was started with
2311 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2312 @option{--cache-failures}}).
2314 @item --clear-failures
2315 Remove the specified store items from the failed-build cache.
2317 Again, this option only makes sense when the daemon is started with
2318 @option{--cache-failures}. Otherwise, it does nothing.
2321 Show the list of dead files and directories still present in the
2322 store---i.e., files and directories no longer reachable from any root.
2325 Show the list of live store files and directories.
2329 In addition, the references among existing store files can be queried:
2335 @cindex package dependencies
2336 List the references (respectively, the referrers) of store files given
2342 List the requisites of the store files passed as arguments. Requisites
2343 include the store files themselves, their references, and the references
2344 of these, recursively. In other words, the returned list is the
2345 @dfn{transitive closure} of the store files.
2347 @xref{Invoking guix size}, for a tool to profile the size of the closure
2348 of an element. @xref{Invoking guix graph}, for a tool to visualize
2349 the graph of references.
2353 Lastly, the following options allow you to check the integrity of the
2354 store and to control disk usage.
2358 @item --verify[=@var{options}]
2359 @cindex integrity, of the store
2360 @cindex integrity checking
2361 Verify the integrity of the store.
2363 By default, make sure that all the store items marked as valid in the
2364 database of the daemon actually exist in @file{/gnu/store}.
2366 When provided, @var{options} must be a comma-separated list containing one
2367 or more of @code{contents} and @code{repair}.
2369 When passing @option{--verify=contents}, the daemon computes the
2370 content hash of each store item and compares it against its hash in the
2371 database. Hash mismatches are reported as data corruptions. Because it
2372 traverses @emph{all the files in the store}, this command can take a
2373 long time, especially on systems with a slow disk drive.
2375 @cindex repairing the store
2376 @cindex corruption, recovering from
2377 Using @option{--verify=repair} or @option{--verify=contents,repair}
2378 causes the daemon to try to repair corrupt store items by fetching
2379 substitutes for them (@pxref{Substitutes}). Because repairing is not
2380 atomic, and thus potentially dangerous, it is available only to the
2381 system administrator. A lightweight alternative, when you know exactly
2382 which items in the store are corrupt, is @command{guix build --repair}
2383 (@pxref{Invoking guix build}).
2386 @cindex deduplication
2387 Optimize the store by hard-linking identical files---this is
2388 @dfn{deduplication}.
2390 The daemon performs deduplication after each successful build or archive
2391 import, unless it was started with @code{--disable-deduplication}
2392 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2393 this option is primarily useful when the daemon was running with
2394 @code{--disable-deduplication}.
2398 @node Invoking guix pull
2399 @section Invoking @command{guix pull}
2401 @cindex upgrading Guix
2402 @cindex updating Guix
2403 @cindex @command{guix pull}
2405 Packages are installed or upgraded to the latest version available in
2406 the distribution currently available on your local machine. To update
2407 that distribution, along with the Guix tools, you must run @command{guix
2408 pull}: the command downloads the latest Guix source code and package
2409 descriptions, and deploys it.
2411 On completion, @command{guix package} will use packages and package
2412 versions from this just-retrieved copy of Guix. Not only that, but all
2413 the Guix commands and Scheme modules will also be taken from that latest
2414 version. New @command{guix} sub-commands added by the update also
2417 Any user can update their Guix copy using @command{guix pull}, and the
2418 effect is limited to the user who run @command{guix pull}. For
2419 instance, when user @code{root} runs @command{guix pull}, this has no
2420 effect on the version of Guix that user @code{alice} sees, and vice
2421 versa@footnote{Under the hood, @command{guix pull} updates the
2422 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2423 and the @command{guix} command loads code from there. Currently, the
2424 only way to roll back an invocation of @command{guix pull} is to
2425 manually update this symlink to point to the previous Guix.}.
2427 The @command{guix pull} command is usually invoked with no arguments,
2428 but it supports the following options:
2432 Produce verbose output, writing build logs to the standard error output.
2434 @item --url=@var{url}
2435 Download the source tarball of Guix from @var{url}.
2437 By default, the tarball is taken from its canonical address at
2438 @code{gnu.org}, for the stable branch of Guix.
2440 With some Git servers, this can be used to deploy any version of Guix.
2441 For example, to download and deploy version 0.12.0 of Guix from the
2445 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2448 It can also be used to deploy arbitrary Git revisions:
2451 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2455 Use the bootstrap Guile to build the latest Guix. This option is only
2456 useful to Guix developers.
2459 In addition, @command{guix pull} supports all the common build options
2460 (@pxref{Common Build Options}).
2462 @node Invoking guix pack
2463 @section Invoking @command{guix pack}
2465 Occasionally you want to pass software to people who are not (yet!)
2466 lucky enough to be using Guix. You'd tell them to run @command{guix
2467 package -i @var{something}}, but that's not possible in this case. This
2468 is where @command{guix pack} comes in.
2472 @cindex application bundle
2473 @cindex software bundle
2474 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2475 @dfn{software bundle}: it creates a tarball or some other archive
2476 containing the binaries of the software you're interested in, and all
2477 its dependencies. The resulting archive can be used on any machine that
2478 does not have Guix, and people can run the exact same binaries as those
2479 you have with Guix. The pack itself is created in a bit-reproducible
2480 fashion, so anyone can verify that it really contains the build results
2481 that you pretend to be shipping.
2483 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2484 their dependencies, you can run:
2487 $ guix pack guile emacs geiser
2489 /gnu/store/@dots{}-pack.tar.gz
2492 The result here is a tarball containing a @file{/gnu/store} directory
2493 with all the relevant packages. The resulting tarball contains a
2494 @dfn{profile} with the three packages of interest; the profile is the
2495 same as would be created by @command{guix package -i}. It is this
2496 mechanism that is used to create Guix's own standalone binary tarball
2497 (@pxref{Binary Installation}).
2499 Users of this pack would have to run
2500 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2501 find inconvenient. To work around it, you can create, say, a
2502 @file{/opt/gnu/bin} symlink to the profile:
2505 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2509 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2511 Alternatively, you can produce a pack in the Docker image format using
2512 the following command:
2515 guix pack -f docker guile emacs geiser
2519 The result is a tarball that can be passed to the @command{docker load}
2521 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2522 documentation} for more information.
2524 Several command-line options allow you to customize your pack:
2527 @item --format=@var{format}
2528 @itemx -f @var{format}
2529 Produce a pack in the given @var{format}.
2531 The available formats are:
2535 This is the default format. It produces a tarball containing all the
2536 specifies binaries and symlinks.
2539 This produces a tarball that follows the
2540 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2541 Docker Image Specification}.
2544 @item --expression=@var{expr}
2545 @itemx -e @var{expr}
2546 Consider the package @var{expr} evaluates to.
2548 This has the same purpose as the same-named option in @command{guix
2549 build} (@pxref{Additional Build Options, @code{--expression} in
2550 @command{guix build}}).
2552 @item --system=@var{system}
2553 @itemx -s @var{system}
2554 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2555 the system type of the build host.
2557 @item --target=@var{triplet}
2558 @cindex cross-compilation
2559 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2560 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2561 configuration triplets,, autoconf, Autoconf}).
2563 @item --compression=@var{tool}
2564 @itemx -C @var{tool}
2565 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2566 @code{bzip2}, @code{xz}, or @code{lzip}.
2568 @item --symlink=@var{spec}
2569 @itemx -S @var{spec}
2570 Add the symlinks specified by @var{spec} to the pack. This option can
2571 appear several times.
2573 @var{spec} has the form @code{@var{source}=@var{target}}, where
2574 @var{source} is the symlink that will be created and @var{target} is the
2577 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2578 symlink pointing to the @file{bin} sub-directory of the profile.
2580 @item --localstatedir
2581 Include the ``local state directory'', @file{/var/guix}, in the
2584 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2585 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2586 the pack means that the store is ``complete'' and manageable by Guix;
2587 not providing it pack means that the store is ``dead'': items cannot be
2588 added to it or removed from it after extraction of the pack.
2590 One use case for this is the Guix self-contained binary tarball
2591 (@pxref{Binary Installation}).
2594 In addition, @command{guix pack} supports all the common build options
2595 (@pxref{Common Build Options}) and all the package transformation
2596 options (@pxref{Package Transformation Options}).
2599 @node Invoking guix archive
2600 @section Invoking @command{guix archive}
2602 @cindex @command{guix archive}
2604 The @command{guix archive} command allows users to @dfn{export} files
2605 from the store into a single archive, and to later @dfn{import} them.
2606 In particular, it allows store files to be transferred from one machine
2607 to the store on another machine.
2609 @cindex exporting store items
2610 To export store files as an archive to standard output, run:
2613 guix archive --export @var{options} @var{specifications}...
2616 @var{specifications} may be either store file names or package
2617 specifications, as for @command{guix package} (@pxref{Invoking guix
2618 package}). For instance, the following command creates an archive
2619 containing the @code{gui} output of the @code{git} package and the main
2620 output of @code{emacs}:
2623 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2626 If the specified packages are not built yet, @command{guix archive}
2627 automatically builds them. The build process may be controlled with the
2628 common build options (@pxref{Common Build Options}).
2630 To transfer the @code{emacs} package to a machine connected over SSH,
2634 guix archive --export -r emacs | ssh the-machine guix archive --import
2638 Similarly, a complete user profile may be transferred from one machine
2639 to another like this:
2642 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2643 ssh the-machine guix-archive --import
2647 However, note that, in both examples, all of @code{emacs} and the
2648 profile as well as all of their dependencies are transferred (due to
2649 @code{-r}), regardless of what is already available in the store on the
2650 target machine. The @code{--missing} option can help figure out which
2651 items are missing from the target store. The @command{guix copy}
2652 command simplifies and optimizes this whole process, so this is probably
2653 what you should use in this case (@pxref{Invoking guix copy}).
2655 @cindex nar, archive format
2656 @cindex normalized archive (nar)
2657 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2658 comparable in spirit to `tar', but with differences
2659 that make it more appropriate for our purposes. First, rather than
2660 recording all Unix metadata for each file, the nar format only mentions
2661 the file type (regular, directory, or symbolic link); Unix permissions
2662 and owner/group are dismissed. Second, the order in which directory
2663 entries are stored always follows the order of file names according to
2664 the C locale collation order. This makes archive production fully
2667 When exporting, the daemon digitally signs the contents of the archive,
2668 and that digital signature is appended. When importing, the daemon
2669 verifies the signature and rejects the import in case of an invalid
2670 signature or if the signing key is not authorized.
2671 @c FIXME: Add xref to daemon doc about signatures.
2673 The main options are:
2677 Export the specified store files or packages (see below.) Write the
2678 resulting archive to the standard output.
2680 Dependencies are @emph{not} included in the output, unless
2681 @code{--recursive} is passed.
2685 When combined with @code{--export}, this instructs @command{guix
2686 archive} to include dependencies of the given items in the archive.
2687 Thus, the resulting archive is self-contained: it contains the closure
2688 of the exported store items.
2691 Read an archive from the standard input, and import the files listed
2692 therein into the store. Abort if the archive has an invalid digital
2693 signature, or if it is signed by a public key not among the authorized
2694 keys (see @code{--authorize} below.)
2697 Read a list of store file names from the standard input, one per line,
2698 and write on the standard output the subset of these files missing from
2701 @item --generate-key[=@var{parameters}]
2702 @cindex signing, archives
2703 Generate a new key pair for the daemon. This is a prerequisite before
2704 archives can be exported with @code{--export}. Note that this operation
2705 usually takes time, because it needs to gather enough entropy to
2706 generate the key pair.
2708 The generated key pair is typically stored under @file{/etc/guix}, in
2709 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2710 key, which must be kept secret.) When @var{parameters} is omitted,
2711 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2712 versions before 1.6.0, it is a 4096-bit RSA key.
2713 Alternatively, @var{parameters} can specify
2714 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2715 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2716 Libgcrypt Reference Manual}).
2719 @cindex authorizing, archives
2720 Authorize imports signed by the public key passed on standard input.
2721 The public key must be in ``s-expression advanced format''---i.e., the
2722 same format as the @file{signing-key.pub} file.
2724 The list of authorized keys is kept in the human-editable file
2725 @file{/etc/guix/acl}. The file contains
2726 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2727 s-expressions''} and is structured as an access-control list in the
2728 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2731 @item --extract=@var{directory}
2732 @itemx -x @var{directory}
2733 Read a single-item archive as served by substitute servers
2734 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2735 low-level operation needed in only very narrow use cases; see below.
2737 For example, the following command extracts the substitute for Emacs
2738 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2742 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2743 | bunzip2 | guix archive -x /tmp/emacs
2746 Single-item archives are different from multiple-item archives produced
2747 by @command{guix archive --export}; they contain a single store item,
2748 and they do @emph{not} embed a signature. Thus this operation does
2749 @emph{no} signature verification and its output should be considered
2752 The primary purpose of this operation is to facilitate inspection of
2753 archive contents coming from possibly untrusted substitute servers.
2757 @c *********************************************************************
2758 @node Programming Interface
2759 @chapter Programming Interface
2761 GNU Guix provides several Scheme programming interfaces (APIs) to
2762 define, build, and query packages. The first interface allows users to
2763 write high-level package definitions. These definitions refer to
2764 familiar packaging concepts, such as the name and version of a package,
2765 its build system, and its dependencies. These definitions can then be
2766 turned into concrete build actions.
2768 Build actions are performed by the Guix daemon, on behalf of users. In a
2769 standard setup, the daemon has write access to the store---the
2770 @file{/gnu/store} directory---whereas users do not. The recommended
2771 setup also has the daemon perform builds in chroots, under a specific
2772 build users, to minimize interference with the rest of the system.
2775 Lower-level APIs are available to interact with the daemon and the
2776 store. To instruct the daemon to perform a build action, users actually
2777 provide it with a @dfn{derivation}. A derivation is a low-level
2778 representation of the build actions to be taken, and the environment in
2779 which they should occur---derivations are to package definitions what
2780 assembly is to C programs. The term ``derivation'' comes from the fact
2781 that build results @emph{derive} from them.
2783 This chapter describes all these APIs in turn, starting from high-level
2784 package definitions.
2787 * Defining Packages:: Defining new packages.
2788 * Build Systems:: Specifying how packages are built.
2789 * The Store:: Manipulating the package store.
2790 * Derivations:: Low-level interface to package derivations.
2791 * The Store Monad:: Purely functional interface to the store.
2792 * G-Expressions:: Manipulating build expressions.
2795 @node Defining Packages
2796 @section Defining Packages
2798 The high-level interface to package definitions is implemented in the
2799 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2800 example, the package definition, or @dfn{recipe}, for the GNU Hello
2801 package looks like this:
2804 (define-module (gnu packages hello)
2805 #:use-module (guix packages)
2806 #:use-module (guix download)
2807 #:use-module (guix build-system gnu)
2808 #:use-module (guix licenses)
2809 #:use-module (gnu packages gawk))
2811 (define-public hello
2817 (uri (string-append "mirror://gnu/hello/hello-" version
2821 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2822 (build-system gnu-build-system)
2823 (arguments '(#:configure-flags '("--enable-silent-rules")))
2824 (inputs `(("gawk" ,gawk)))
2825 (synopsis "Hello, GNU world: An example GNU package")
2826 (description "Guess what GNU Hello prints!")
2827 (home-page "http://www.gnu.org/software/hello/")
2832 Without being a Scheme expert, the reader may have guessed the meaning
2833 of the various fields here. This expression binds the variable
2834 @code{hello} to a @code{<package>} object, which is essentially a record
2835 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2836 This package object can be inspected using procedures found in the
2837 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2838 returns---surprise!---@code{"hello"}.
2840 With luck, you may be able to import part or all of the definition of
2841 the package you are interested in from another repository, using the
2842 @code{guix import} command (@pxref{Invoking guix import}).
2844 In the example above, @var{hello} is defined in a module of its own,
2845 @code{(gnu packages hello)}. Technically, this is not strictly
2846 necessary, but it is convenient to do so: all the packages defined in
2847 modules under @code{(gnu packages @dots{})} are automatically known to
2848 the command-line tools (@pxref{Package Modules}).
2850 There are a few points worth noting in the above package definition:
2854 The @code{source} field of the package is an @code{<origin>} object
2855 (@pxref{origin Reference}, for the complete reference).
2856 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2857 meaning that the source is a file to be downloaded over FTP or HTTP.
2859 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2860 the GNU mirrors defined in @code{(guix download)}.
2862 The @code{sha256} field specifies the expected SHA256 hash of the file
2863 being downloaded. It is mandatory, and allows Guix to check the
2864 integrity of the file. The @code{(base32 @dots{})} form introduces the
2865 base32 representation of the hash. You can obtain this information with
2866 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2867 hash} (@pxref{Invoking guix hash}).
2870 When needed, the @code{origin} form can also have a @code{patches} field
2871 listing patches to be applied, and a @code{snippet} field giving a
2872 Scheme expression to modify the source code.
2875 @cindex GNU Build System
2876 The @code{build-system} field specifies the procedure to build the
2877 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2878 represents the familiar GNU Build System, where packages may be
2879 configured, built, and installed with the usual @code{./configure &&
2880 make && make check && make install} command sequence.
2883 The @code{arguments} field specifies options for the build system
2884 (@pxref{Build Systems}). Here it is interpreted by
2885 @var{gnu-build-system} as a request run @file{configure} with the
2886 @code{--enable-silent-rules} flag.
2892 What about these quote (@code{'}) characters? They are Scheme syntax to
2893 introduce a literal list; @code{'} is synonymous with @code{quote}.
2894 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2895 for details. Here the value of the @code{arguments} field is a list of
2896 arguments passed to the build system down the road, as with @code{apply}
2897 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2900 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2901 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2902 @code{#:configure-flags} is a keyword used to pass a keyword argument
2903 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2907 The @code{inputs} field specifies inputs to the build process---i.e.,
2908 build-time or run-time dependencies of the package. Here, we define an
2909 input called @code{"gawk"} whose value is that of the @var{gawk}
2910 variable; @var{gawk} is itself bound to a @code{<package>} object.
2912 @cindex backquote (quasiquote)
2915 @cindex comma (unquote)
2919 @findex unquote-splicing
2920 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2921 us to introduce a literal list in the @code{inputs} field, while
2922 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2923 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2926 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2927 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2928 of ensuring that they are present (@pxref{Build Systems}).
2930 However, any other dependencies need to be specified in the
2931 @code{inputs} field. Any dependency not specified here will simply be
2932 unavailable to the build process, possibly leading to a build failure.
2935 @xref{package Reference}, for a full description of possible fields.
2937 Once a package definition is in place, the
2938 package may actually be built using the @code{guix build} command-line
2939 tool (@pxref{Invoking guix build}), troubleshooting any build failures
2940 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
2941 package definition using the @command{guix edit} command
2942 (@pxref{Invoking guix edit}).
2943 @xref{Packaging Guidelines}, for
2944 more information on how to test package definitions, and
2945 @ref{Invoking guix lint}, for information on how to check a definition
2946 for style conformance.
2947 @vindex GUIX_PACKAGE_PATH
2948 Lastly, @pxref{Package Modules}, for information
2949 on how to extend the distribution by adding your own package definitions
2950 to @code{GUIX_PACKAGE_PATH}.
2952 Finally, updating the package definition to a new upstream version
2953 can be partly automated by the @command{guix refresh} command
2954 (@pxref{Invoking guix refresh}).
2956 Behind the scenes, a derivation corresponding to the @code{<package>}
2957 object is first computed by the @code{package-derivation} procedure.
2958 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2959 The build actions it prescribes may then be realized by using the
2960 @code{build-derivations} procedure (@pxref{The Store}).
2962 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2963 Return the @code{<derivation>} object of @var{package} for @var{system}
2964 (@pxref{Derivations}).
2966 @var{package} must be a valid @code{<package>} object, and @var{system}
2967 must be a string denoting the target system type---e.g.,
2968 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2969 must be a connection to the daemon, which operates on the store
2970 (@pxref{The Store}).
2974 @cindex cross-compilation
2975 Similarly, it is possible to compute a derivation that cross-builds a
2976 package for some other system:
2978 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2979 @var{package} @var{target} [@var{system}]
2980 Return the @code{<derivation>} object of @var{package} cross-built from
2981 @var{system} to @var{target}.
2983 @var{target} must be a valid GNU triplet denoting the target hardware
2984 and operating system, such as @code{"mips64el-linux-gnu"}
2985 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2986 Configure and Build System}).
2989 @cindex package transformations
2990 @cindex input rewriting
2991 @cindex dependency tree rewriting
2992 Packages can be manipulated in arbitrary ways. An example of a useful
2993 transformation is @dfn{input rewriting}, whereby the dependency tree of
2994 a package is rewritten by replacing specific inputs by others:
2996 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2997 [@var{rewrite-name}]
2998 Return a procedure that, when passed a package, replaces its direct and
2999 indirect dependencies (but not its implicit inputs) according to
3000 @var{replacements}. @var{replacements} is a list of package pairs; the
3001 first element of each pair is the package to replace, and the second one
3004 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3005 the name of a package and returns its new name after rewrite.
3009 Consider this example:
3012 (define libressl-instead-of-openssl
3013 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3015 (package-input-rewriting `((,openssl . ,libressl))))
3017 (define git-with-libressl
3018 (libressl-instead-of-openssl git))
3022 Here we first define a rewriting procedure that replaces @var{openssl}
3023 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3024 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3025 This is exactly what the @option{--with-input} command-line option does
3026 (@pxref{Package Transformation Options, @option{--with-input}}).
3028 A more generic procedure to rewrite a package dependency graph is
3029 @code{package-mapping}: it supports arbitrary changes to nodes in the
3032 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3033 Return a procedure that, given a package, applies @var{proc} to all the packages
3034 depended on and returns the resulting package. The procedure stops recursion
3035 when @var{cut?} returns true for a given package.
3039 * package Reference :: The package data type.
3040 * origin Reference:: The origin data type.
3044 @node package Reference
3045 @subsection @code{package} Reference
3047 This section summarizes all the options available in @code{package}
3048 declarations (@pxref{Defining Packages}).
3050 @deftp {Data Type} package
3051 This is the data type representing a package recipe.
3055 The name of the package, as a string.
3057 @item @code{version}
3058 The version of the package, as a string.
3061 An object telling how the source code for the package should be
3062 acquired. Most of the time, this is an @code{origin} object, which
3063 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3064 can also be any other ``file-like'' object such as a @code{local-file},
3065 which denotes a file from the local file system (@pxref{G-Expressions,
3066 @code{local-file}}).
3068 @item @code{build-system}
3069 The build system that should be used to build the package (@pxref{Build
3072 @item @code{arguments} (default: @code{'()})
3073 The arguments that should be passed to the build system. This is a
3074 list, typically containing sequential keyword-value pairs.
3076 @item @code{inputs} (default: @code{'()})
3077 @itemx @code{native-inputs} (default: @code{'()})
3078 @itemx @code{propagated-inputs} (default: @code{'()})
3079 @cindex inputs, of packages
3080 These fields list dependencies of the package. Each one is a list of
3081 tuples, where each tuple has a label for the input (a string) as its
3082 first element, a package, origin, or derivation as its second element,
3083 and optionally the name of the output thereof that should be used, which
3084 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3085 more on package outputs). For example, the list below specifies three
3089 `(("libffi" ,libffi)
3090 ("libunistring" ,libunistring)
3091 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3094 @cindex cross compilation, package dependencies
3095 The distinction between @code{native-inputs} and @code{inputs} is
3096 necessary when considering cross-compilation. When cross-compiling,
3097 dependencies listed in @code{inputs} are built for the @emph{target}
3098 architecture; conversely, dependencies listed in @code{native-inputs}
3099 are built for the architecture of the @emph{build} machine.
3101 @code{native-inputs} is typically used to list tools needed at
3102 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3103 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3104 this area (@pxref{Invoking guix lint}).
3106 @anchor{package-propagated-inputs}
3107 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3108 specified packages will be automatically installed alongside the package
3109 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3110 package}}, for information on how @command{guix package} deals with
3113 For example this is necessary when a C/C++ library needs headers of
3114 another library to compile, or when a pkg-config file refers to another
3115 one @i{via} its @code{Requires} field.
3117 Another example where @code{propagated-inputs} is useful is for languages
3118 that lack a facility to record the run-time search path akin to the
3119 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3120 more. To ensure that libraries written in those languages can find
3121 library code they depend on at run time, run-time dependencies must be
3122 listed in @code{propagated-inputs} rather than @code{inputs}.
3124 @item @code{self-native-input?} (default: @code{#f})
3125 This is a Boolean field telling whether the package should use itself as
3126 a native input when cross-compiling.
3128 @item @code{outputs} (default: @code{'("out")})
3129 The list of output names of the package. @xref{Packages with Multiple
3130 Outputs}, for typical uses of additional outputs.
3132 @item @code{native-search-paths} (default: @code{'()})
3133 @itemx @code{search-paths} (default: @code{'()})
3134 A list of @code{search-path-specification} objects describing
3135 search-path environment variables honored by the package.
3137 @item @code{replacement} (default: @code{#f})
3138 This must be either @code{#f} or a package object that will be used as a
3139 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3142 @item @code{synopsis}
3143 A one-line description of the package.
3145 @item @code{description}
3146 A more elaborate description of the package.
3148 @item @code{license}
3149 @cindex license, of packages
3150 The license of the package; a value from @code{(guix licenses)},
3151 or a list of such values.
3153 @item @code{home-page}
3154 The URL to the home-page of the package, as a string.
3156 @item @code{supported-systems} (default: @var{%supported-systems})
3157 The list of systems supported by the package, as strings of the form
3158 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3160 @item @code{maintainers} (default: @code{'()})
3161 The list of maintainers of the package, as @code{maintainer} objects.
3163 @item @code{location} (default: source location of the @code{package} form)
3164 The source location of the package. It is useful to override this when
3165 inheriting from another package, in which case this field is not
3166 automatically corrected.
3171 @node origin Reference
3172 @subsection @code{origin} Reference
3174 This section summarizes all the options available in @code{origin}
3175 declarations (@pxref{Defining Packages}).
3177 @deftp {Data Type} origin
3178 This is the data type representing a source code origin.
3182 An object containing the URI of the source. The object type depends on
3183 the @code{method} (see below). For example, when using the
3184 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3185 values are: a URL represented as a string, or a list thereof.
3188 A procedure that handles the URI.
3193 @item @var{url-fetch} from @code{(guix download)}
3194 download a file from the HTTP, HTTPS, or FTP URL specified in the
3198 @item @var{git-fetch} from @code{(guix git-download)}
3199 clone the Git version control repository, and check out the revision
3200 specified in the @code{uri} field as a @code{git-reference} object; a
3201 @code{git-reference} looks like this:
3205 (url "git://git.debian.org/git/pkg-shadow/shadow")
3206 (commit "v4.1.5.1"))
3211 A bytevector containing the SHA-256 hash of the source. Typically the
3212 @code{base32} form is used here to generate the bytevector from a
3215 You can obtain this information using @code{guix download}
3216 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3219 @item @code{file-name} (default: @code{#f})
3220 The file name under which the source code should be saved. When this is
3221 @code{#f}, a sensible default value will be used in most cases. In case
3222 the source is fetched from a URL, the file name from the URL will be
3223 used. For version control checkouts, it is recommended to provide the
3224 file name explicitly because the default is not very descriptive.
3226 @item @code{patches} (default: @code{'()})
3227 A list of file names containing patches to be applied to the source.
3229 This list of patches must be unconditional. In particular, it cannot
3230 depend on the value of @code{%current-system} or
3231 @code{%current-target-system}.
3233 @item @code{snippet} (default: @code{#f})
3234 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3235 in the source directory. This is a convenient way to modify the source,
3236 sometimes more convenient than a patch.
3238 @item @code{patch-flags} (default: @code{'("-p1")})
3239 A list of command-line flags that should be passed to the @code{patch}
3242 @item @code{patch-inputs} (default: @code{#f})
3243 Input packages or derivations to the patching process. When this is
3244 @code{#f}, the usual set of inputs necessary for patching are provided,
3245 such as GNU@tie{}Patch.
3247 @item @code{modules} (default: @code{'()})
3248 A list of Guile modules that should be loaded during the patching
3249 process and while running the code in the @code{snippet} field.
3251 @item @code{patch-guile} (default: @code{#f})
3252 The Guile package that should be used in the patching process. When
3253 this is @code{#f}, a sensible default is used.
3259 @section Build Systems
3261 @cindex build system
3262 Each package definition specifies a @dfn{build system} and arguments for
3263 that build system (@pxref{Defining Packages}). This @code{build-system}
3264 field represents the build procedure of the package, as well as implicit
3265 dependencies of that build procedure.
3267 Build systems are @code{<build-system>} objects. The interface to
3268 create and manipulate them is provided by the @code{(guix build-system)}
3269 module, and actual build systems are exported by specific modules.
3271 @cindex bag (low-level package representation)
3272 Under the hood, build systems first compile package objects to
3273 @dfn{bags}. A @dfn{bag} is like a package, but with less
3274 ornamentation---in other words, a bag is a lower-level representation of
3275 a package, which includes all the inputs of that package, including some
3276 that were implicitly added by the build system. This intermediate
3277 representation is then compiled to a derivation (@pxref{Derivations}).
3279 Build systems accept an optional list of @dfn{arguments}. In package
3280 definitions, these are passed @i{via} the @code{arguments} field
3281 (@pxref{Defining Packages}). They are typically keyword arguments
3282 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3283 Guile Reference Manual}). The value of these arguments is usually
3284 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3285 by the daemon (@pxref{Derivations}).
3287 The main build system is @var{gnu-build-system}, which implements the
3288 standard build procedure for GNU and many other packages. It
3289 is provided by the @code{(guix build-system gnu)} module.
3291 @defvr {Scheme Variable} gnu-build-system
3292 @var{gnu-build-system} represents the GNU Build System, and variants
3293 thereof (@pxref{Configuration, configuration and makefile conventions,,
3294 standards, GNU Coding Standards}).
3296 @cindex build phases
3297 In a nutshell, packages using it are configured, built, and installed with
3298 the usual @code{./configure && make && make check && make install}
3299 command sequence. In practice, a few additional steps are often needed.
3300 All these steps are split up in separate @dfn{phases},
3301 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3302 modules for more details about the build phases.}:
3306 Unpack the source tarball, and change the current directory to the
3307 extracted source tree. If the source is actually a directory, copy it
3308 to the build tree, and enter that directory.
3310 @item patch-source-shebangs
3311 Patch shebangs encountered in source files so they refer to the right
3312 store file names. For instance, this changes @code{#!/bin/sh} to
3313 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3316 Run the @file{configure} script with a number of default options, such
3317 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3318 by the @code{#:configure-flags} argument.
3321 Run @code{make} with the list of flags specified with
3322 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3323 (the default), build with @code{make -j}.
3326 Run @code{make check}, or some other target specified with
3327 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3328 @code{#:parallel-tests?} argument is true (the default), run @code{make
3332 Run @code{make install} with the flags listed in @code{#:make-flags}.
3334 @item patch-shebangs
3335 Patch shebangs on the installed executable files.
3338 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3339 is false), copying them to the @code{debug} output when available
3340 (@pxref{Installing Debugging Files}).
3343 @vindex %standard-phases
3344 The build-side module @code{(guix build gnu-build-system)} defines
3345 @var{%standard-phases} as the default list of build phases.
3346 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3347 procedure implements the actual phase.
3349 The list of phases used for a particular package can be changed with the
3350 @code{#:phases} parameter. For instance, passing:
3353 #:phases (modify-phases %standard-phases (delete 'configure))
3356 means that all the phases described above will be used, except the
3357 @code{configure} phase.
3359 In addition, this build system ensures that the ``standard'' environment
3360 for GNU packages is available. This includes tools such as GCC, libc,
3361 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3362 build-system gnu)} module for a complete list). We call these the
3363 @dfn{implicit inputs} of a package, because package definitions do not
3364 have to mention them.
3367 Other @code{<build-system>} objects are defined to support other
3368 conventions and tools used by free software packages. They inherit most
3369 of @var{gnu-build-system}, and differ mainly in the set of inputs
3370 implicitly added to the build process, and in the list of phases
3371 executed. Some of these build systems are listed below.
3373 @defvr {Scheme Variable} ant-build-system
3374 This variable is exported by @code{(guix build-system ant)}. It
3375 implements the build procedure for Java packages that can be built with
3376 @url{http://ant.apache.org/, Ant build tool}.
3378 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3379 provided by the @code{icedtea} package to the set of inputs. Different
3380 packages can be specified with the @code{#:ant} and @code{#:jdk}
3381 parameters, respectively.
3383 When the original package does not provide a suitable Ant build file,
3384 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3385 build file @file{build.xml} with tasks to build the specified jar
3386 archive. In this case the parameter @code{#:source-dir} can be used to
3387 specify the source sub-directory, defaulting to ``src''.
3389 The parameter @code{#:build-target} can be used to specify the Ant task
3390 that should be run during the @code{build} phase. By default the
3391 ``jar'' task will be run.
3395 @defvr {Scheme Variable} asdf-build-system/source
3396 @defvrx {Scheme Variable} asdf-build-system/sbcl
3397 @defvrx {Scheme Variable} asdf-build-system/ecl
3399 These variables, exported by @code{(guix build-system asdf)}, implement
3400 build procedures for Common Lisp packages using
3401 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3402 definition facility for Common Lisp programs and libraries.
3404 The @code{asdf-build-system/source} system installs the packages in
3405 source form, and can be loaded using any common lisp implementation, via
3406 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3407 systems in the format which a particular implementation understands.
3408 These build systems can also be used to produce executable programs, or
3409 lisp images which contain a set of packages pre-loaded.
3411 The build system uses naming conventions. For binary packages, the
3412 package name should be prefixed with the lisp implementation, such as
3413 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3415 Additionally, the corresponding source package should be labeled using
3416 the same convention as python packages (see @ref{Python Modules}), using
3417 the @code{cl-} prefix.
3419 For binary packages, each system should be defined as a Guix package.
3420 If one package @code{origin} contains several systems, package variants
3421 can be created in order to build all the systems. Source packages,
3422 which use @code{asdf-build-system/source}, may contain several systems.
3424 In order to create executable programs and images, the build-side
3425 procedures @code{build-program} and @code{build-image} can be used.
3426 They should be called in a build phase after the @code{create-symlinks}
3427 phase, so that the system which was just built can be used within the
3428 resulting image. @code{build-program} requires a list of Common Lisp
3429 expressions to be passed as the @code{#:entry-program} argument.
3431 If the system is not defined within its own @code{.asd} file of the same
3432 name, then the @code{#:asd-file} parameter should be used to specify
3433 which file the system is defined in. Furthermore, if the package
3434 defines a system for its tests in a separate file, it will be loaded
3435 before the tests are run if it is specified by the
3436 @code{#:test-asd-file} parameter. If it is not set, the files
3437 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3438 and @code{test.asd} will be tried if they exist.
3440 If for some reason the package must be named in a different way than the
3441 naming conventions suggest, the @code{#:asd-system-name} parameter can
3442 be used to specify the name of the system.
3446 @defvr {Scheme Variable} cargo-build-system
3447 @cindex Rust programming language
3448 @cindex Cargo (Rust build system)
3449 This variable is exported by @code{(guix build-system cargo)}. It
3450 supports builds of packages using Cargo, the build tool of the
3451 @uref{https://www.rust-lang.org, Rust programming language}.
3453 In its @code{configure} phase, this build system replaces dependencies
3454 specified in the @file{Carto.toml} file with inputs to the Guix package.
3455 The @code{install} phase installs the binaries, and it also installs the
3456 source code and @file{Cargo.toml} file.
3459 @defvr {Scheme Variable} cmake-build-system
3460 This variable is exported by @code{(guix build-system cmake)}. It
3461 implements the build procedure for packages using the
3462 @url{http://www.cmake.org, CMake build tool}.
3464 It automatically adds the @code{cmake} package to the set of inputs.
3465 Which package is used can be specified with the @code{#:cmake}
3468 The @code{#:configure-flags} parameter is taken as a list of flags
3469 passed to the @command{cmake} command. The @code{#:build-type}
3470 parameter specifies in abstract terms the flags passed to the compiler;
3471 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3472 debugging information''), which roughly means that code is compiled with
3473 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3476 @defvr {Scheme Variable} glib-or-gtk-build-system
3477 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3478 is intended for use with packages making use of GLib or GTK+.
3480 This build system adds the following two phases to the ones defined by
3481 @var{gnu-build-system}:
3484 @item glib-or-gtk-wrap
3485 The phase @code{glib-or-gtk-wrap} ensures that programs in
3486 @file{bin/} are able to find GLib ``schemas'' and
3487 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3488 modules}. This is achieved by wrapping the programs in launch scripts
3489 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3490 environment variables.
3492 It is possible to exclude specific package outputs from that wrapping
3493 process by listing their names in the
3494 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3495 when an output is known not to contain any GLib or GTK+ binaries, and
3496 where wrapping would gratuitously add a dependency of that output on
3499 @item glib-or-gtk-compile-schemas
3500 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3501 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3502 GSettings schemas} of GLib are compiled. Compilation is performed by the
3503 @command{glib-compile-schemas} program. It is provided by the package
3504 @code{glib:bin} which is automatically imported by the build system.
3505 The @code{glib} package providing @command{glib-compile-schemas} can be
3506 specified with the @code{#:glib} parameter.
3509 Both phases are executed after the @code{install} phase.
3512 @defvr {Scheme Variable} ocaml-build-system
3513 This variable is exported by @code{(guix build-system ocaml)}. It implements
3514 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3515 of choosing the correct set of commands to run for each package. OCaml
3516 packages can expect many different commands to be run. This build system will
3519 When the package has a @file{setup.ml} file present at the top-level, it will
3520 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3521 @code{ocaml setup.ml -install}. The build system will assume that this file
3522 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3523 care of setting the prefix and enabling tests if they are not disabled. You
3524 can pass configure and build flags with the @code{#:configure-flags} and
3525 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3526 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3527 bypass this system in the build and install phases.
3529 When the package has a @file{configure} file, it is assumed that it is a
3530 hand-made configure script that requires a different argument format than
3531 in the @code{gnu-build-system}. You can add more flags with the
3532 @code{#:configure-flags} key.
3534 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3535 @code{#t}), it will be used and more flags can be passed to the build and
3536 install phases with the @code{#:make-flags} key.
3538 Finally, some packages do not have these files and use a somewhat standard
3539 location for its build system. In that case, the build system will run
3540 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3541 providing the path to the required findlib module. Additional flags can
3542 be passed via the @code{#:build-flags} key. Install is taken care of by
3543 @command{opam-installer}. In this case, the @code{opam} package must
3544 be added to the @code{native-inputs} field of the package definition.
3546 Note that most OCaml packages assume they will be installed in the same
3547 directory as OCaml, which is not what we want in guix. In particular, they
3548 will install @file{.so} files in their module's directory, which is usually
3549 fine because it is in the OCaml compiler directory. In guix though, these
3550 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3551 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3552 @file{.so} libraries should be installed.
3555 @defvr {Scheme Variable} python-build-system
3556 This variable is exported by @code{(guix build-system python)}. It
3557 implements the more or less standard build procedure used by Python
3558 packages, which consists in running @code{python setup.py build} and
3559 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3561 For packages that install stand-alone Python programs under @code{bin/},
3562 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3563 environment variable points to all the Python libraries they depend on.
3565 Which Python package is used to perform the build can be specified with
3566 the @code{#:python} parameter. This is a useful way to force a package
3567 to be built for a specific version of the Python interpreter, which
3568 might be necessary if the package is only compatible with a single
3569 interpreter version.
3571 By default guix calls @code{setup.py} under control of
3572 @code{setuptools}, much like @command{pip} does. Some packages are not
3573 compatible with setuptools (and pip), thus you can disable this by
3574 setting the @code{#:use-setuptools} parameter to @code{#f}.
3577 @defvr {Scheme Variable} perl-build-system
3578 This variable is exported by @code{(guix build-system perl)}. It
3579 implements the standard build procedure for Perl packages, which either
3580 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3581 followed by @code{Build} and @code{Build install}; or in running
3582 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3583 @code{make} and @code{make install}, depending on which of
3584 @code{Build.PL} or @code{Makefile.PL} is present in the package
3585 distribution. Preference is given to the former if both @code{Build.PL}
3586 and @code{Makefile.PL} exist in the package distribution. This
3587 preference can be reversed by specifying @code{#t} for the
3588 @code{#:make-maker?} parameter.
3590 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3591 passes flags specified by the @code{#:make-maker-flags} or
3592 @code{#:module-build-flags} parameter, respectively.
3594 Which Perl package is used can be specified with @code{#:perl}.
3597 @defvr {Scheme Variable} r-build-system
3598 This variable is exported by @code{(guix build-system r)}. It
3599 implements the build procedure used by @uref{http://r-project.org, R}
3600 packages, which essentially is little more than running @code{R CMD
3601 INSTALL --library=/gnu/store/@dots{}} in an environment where
3602 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3603 are run after installation using the R function
3604 @code{tools::testInstalledPackage}.
3607 @defvr {Scheme Variable} texlive-build-system
3608 This variable is exported by @code{(guix build-system texlive)}. It is
3609 used to build TeX packages in batch mode with a specified engine. The
3610 build system sets the @code{TEXINPUTS} variable to find all TeX source
3611 files in the inputs.
3613 By default it runs @code{luatex} on all files ending on @code{ins}. A
3614 different engine and format can be specified with the
3615 @code{#:tex-format} argument. Different build targets can be specified
3616 with the @code{#:build-targets} argument, which expects a list of file
3617 names. The build system adds only @code{texlive-bin} and
3618 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3619 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3620 and @code{#:texlive-latex-base}, respectively.
3622 The @code{#:tex-directory} parameter tells the build system where to
3623 install the built files under the texmf tree.
3626 @defvr {Scheme Variable} ruby-build-system
3627 This variable is exported by @code{(guix build-system ruby)}. It
3628 implements the RubyGems build procedure used by Ruby packages, which
3629 involves running @code{gem build} followed by @code{gem install}.
3631 The @code{source} field of a package that uses this build system
3632 typically references a gem archive, since this is the format that Ruby
3633 developers use when releasing their software. The build system unpacks
3634 the gem archive, potentially patches the source, runs the test suite,
3635 repackages the gem, and installs it. Additionally, directories and
3636 tarballs may be referenced to allow building unreleased gems from Git or
3637 a traditional source release tarball.
3639 Which Ruby package is used can be specified with the @code{#:ruby}
3640 parameter. A list of additional flags to be passed to the @command{gem}
3641 command can be specified with the @code{#:gem-flags} parameter.
3644 @defvr {Scheme Variable} waf-build-system
3645 This variable is exported by @code{(guix build-system waf)}. It
3646 implements a build procedure around the @code{waf} script. The common
3647 phases---@code{configure}, @code{build}, and @code{install}---are
3648 implemented by passing their names as arguments to the @code{waf}
3651 The @code{waf} script is executed by the Python interpreter. Which
3652 Python package is used to run the script can be specified with the
3653 @code{#:python} parameter.
3656 @defvr {Scheme Variable} haskell-build-system
3657 This variable is exported by @code{(guix build-system haskell)}. It
3658 implements the Cabal build procedure used by Haskell packages, which
3659 involves running @code{runhaskell Setup.hs configure
3660 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3661 Instead of installing the package by running @code{runhaskell Setup.hs
3662 install}, to avoid trying to register libraries in the read-only
3663 compiler store directory, the build system uses @code{runhaskell
3664 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3665 addition, the build system generates the package documentation by
3666 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3667 is passed. Optional Haddock parameters can be passed with the help of
3668 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3669 not found, the build system looks for @code{Setup.lhs} instead.
3671 Which Haskell compiler is used can be specified with the @code{#:haskell}
3672 parameter which defaults to @code{ghc}.
3675 @defvr {Scheme Variable} dub-build-system
3676 This variable is exported by @code{(guix build-system dub)}. It
3677 implements the Dub build procedure used by D packages, which
3678 involves running @code{dub build} and @code{dub run}.
3679 Installation is done by copying the files manually.
3681 Which D compiler is used can be specified with the @code{#:ldc}
3682 parameter which defaults to @code{ldc}.
3685 @defvr {Scheme Variable} emacs-build-system
3686 This variable is exported by @code{(guix build-system emacs)}. It
3687 implements an installation procedure similar to the packaging system
3688 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3690 It first creates the @code{@var{package}-autoloads.el} file, then it
3691 byte compiles all Emacs Lisp files. Differently from the Emacs
3692 packaging system, the Info documentation files are moved to the standard
3693 documentation directory and the @file{dir} file is deleted. Each
3694 package is installed in its own directory under
3695 @file{share/emacs/site-lisp/guix.d}.
3698 @defvr {Scheme Variable} font-build-system
3699 This variable is exported by @code{(guix build-system font)}. It
3700 implements an installation procedure for font packages where upstream
3701 provides pre-compiled TrueType, OpenType, etc. font files that merely
3702 need to be copied into place. It copies font files to standard
3703 locations in the output directory.
3706 Lastly, for packages that do not need anything as sophisticated, a
3707 ``trivial'' build system is provided. It is trivial in the sense that
3708 it provides basically no support: it does not pull any implicit inputs,
3709 and does not have a notion of build phases.
3711 @defvr {Scheme Variable} trivial-build-system
3712 This variable is exported by @code{(guix build-system trivial)}.
3714 This build system requires a @code{#:builder} argument. This argument
3715 must be a Scheme expression that builds the package output(s)---as
3716 with @code{build-expression->derivation} (@pxref{Derivations,
3717 @code{build-expression->derivation}}).
3727 Conceptually, the @dfn{store} is the place where derivations that have
3728 been built successfully are stored---by default, @file{/gnu/store}.
3729 Sub-directories in the store are referred to as @dfn{store items} or
3730 sometimes @dfn{store paths}. The store has an associated database that
3731 contains information such as the store paths referred to by each store
3732 path, and the list of @emph{valid} store items---results of successful
3733 builds. This database resides in @file{@var{localstatedir}/guix/db},
3734 where @var{localstatedir} is the state directory specified @i{via}
3735 @option{--localstatedir} at configure time, usually @file{/var}.
3737 The store is @emph{always} accessed by the daemon on behalf of its clients
3738 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3739 connect to the daemon over a Unix-domain socket, send requests to it,
3740 and read the result---these are remote procedure calls, or RPCs.
3743 Users must @emph{never} modify files under @file{/gnu/store} directly.
3744 This would lead to inconsistencies and break the immutability
3745 assumptions of Guix's functional model (@pxref{Introduction}).
3747 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3748 how to check the integrity of the store and attempt recovery from
3749 accidental modifications.
3752 The @code{(guix store)} module provides procedures to connect to the
3753 daemon, and to perform RPCs. These are described below. By default,
3754 @code{open-connection}, and thus all the @command{guix} commands,
3755 connect to the local daemon or to the URI specified by the
3756 @code{GUIX_DAEMON_SOCKET} environment variable.
3758 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3759 When set, the value of this variable should be a file name or a URI
3760 designating the daemon endpoint. When it is a file name, it denotes a
3761 Unix-domain socket to connect to. In addition to file names, the
3762 supported URI schemes are:
3767 These are for Unix-domain sockets.
3768 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3769 @file{/var/guix/daemon-socket/socket}.
3772 These URIs denote connections over TCP/IP, without encryption nor
3773 authentication of the remote host. The URI must always specify both the
3774 host name and port number:
3777 guix://master.guix.example.org:1234
3780 This setup is suitable on local networks, such as clusters, where only
3781 trusted nodes may connect to the build daemon at
3782 @code{master.guix.example.org}.
3785 @cindex SSH access to build daemons
3786 These URIs allow you to connect to a remote daemon over
3787 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3788 A typical URL might look like this:
3791 ssh://charlie@@guix.example.org:22
3794 As for @command{guix copy}, the usual OpenSSH client configuration files
3795 are honored (@pxref{Invoking guix copy}).
3798 Additional URI schemes may be supported in the future.
3800 @c XXX: Remove this note when the protocol incurs fewer round trips
3801 @c and when (guix derivations) no longer relies on file system access.
3803 The ability to connect to remote build daemons is considered
3804 experimental as of @value{VERSION}. Please get in touch with us to
3805 share any problems or suggestions you may have (@pxref{Contributing}).
3809 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3810 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3811 @var{reserve-space?} is true, instruct it to reserve a little bit of
3812 extra space on the file system so that the garbage collector can still
3813 operate should the disk become full. Return a server object.
3815 @var{file} defaults to @var{%default-socket-path}, which is the normal
3816 location given the options that were passed to @command{configure}.
3819 @deffn {Scheme Procedure} close-connection @var{server}
3820 Close the connection to @var{server}.
3823 @defvr {Scheme Variable} current-build-output-port
3824 This variable is bound to a SRFI-39 parameter, which refers to the port
3825 where build and error logs sent by the daemon should be written.
3828 Procedures that make RPCs all take a server object as their first
3831 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3832 @cindex invalid store items
3833 Return @code{#t} when @var{path} designates a valid store item and
3834 @code{#f} otherwise (an invalid item may exist on disk but still be
3835 invalid, for instance because it is the result of an aborted or failed
3838 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3839 prefixed by the store directory (@file{/gnu/store}).
3842 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3843 Add @var{text} under file @var{name} in the store, and return its store
3844 path. @var{references} is the list of store paths referred to by the
3845 resulting store path.
3848 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3849 Build @var{derivations} (a list of @code{<derivation>} objects or
3850 derivation paths), and return when the worker is done building them.
3851 Return @code{#t} on success.
3854 Note that the @code{(guix monads)} module provides a monad as well as
3855 monadic versions of the above procedures, with the goal of making it
3856 more convenient to work with code that accesses the store (@pxref{The
3860 @i{This section is currently incomplete.}
3863 @section Derivations
3866 Low-level build actions and the environment in which they are performed
3867 are represented by @dfn{derivations}. A derivation contains the
3868 following pieces of information:
3872 The outputs of the derivation---derivations produce at least one file or
3873 directory in the store, but may produce more.
3876 The inputs of the derivations, which may be other derivations or plain
3877 files in the store (patches, build scripts, etc.)
3880 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3883 The file name of a build script in the store, along with the arguments
3887 A list of environment variables to be defined.
3891 @cindex derivation path
3892 Derivations allow clients of the daemon to communicate build actions to
3893 the store. They exist in two forms: as an in-memory representation,
3894 both on the client- and daemon-side, and as files in the store whose
3895 name end in @code{.drv}---these files are referred to as @dfn{derivation
3896 paths}. Derivations paths can be passed to the @code{build-derivations}
3897 procedure to perform the build actions they prescribe (@pxref{The
3900 The @code{(guix derivations)} module provides a representation of
3901 derivations as Scheme objects, along with procedures to create and
3902 otherwise manipulate derivations. The lowest-level primitive to create
3903 a derivation is the @code{derivation} procedure:
3905 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3906 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3907 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3908 [#:system (%current-system)] [#:references-graphs #f] @
3909 [#:allowed-references #f] [#:disallowed-references #f] @
3910 [#:leaked-env-vars #f] [#:local-build? #f] @
3911 [#:substitutable? #t]
3912 Build a derivation with the given arguments, and return the resulting
3913 @code{<derivation>} object.
3915 When @var{hash} and @var{hash-algo} are given, a
3916 @dfn{fixed-output derivation} is created---i.e., one whose result is
3917 known in advance, such as a file download. If, in addition,
3918 @var{recursive?} is true, then that fixed output may be an executable
3919 file or a directory and @var{hash} must be the hash of an archive
3920 containing this output.
3922 When @var{references-graphs} is true, it must be a list of file
3923 name/store path pairs. In that case, the reference graph of each store
3924 path is exported in the build environment in the corresponding file, in
3925 a simple text format.
3927 When @var{allowed-references} is true, it must be a list of store items
3928 or outputs that the derivation's output may refer to. Likewise,
3929 @var{disallowed-references}, if true, must be a list of things the
3930 outputs may @emph{not} refer to.
3932 When @var{leaked-env-vars} is true, it must be a list of strings
3933 denoting environment variables that are allowed to ``leak'' from the
3934 daemon's environment to the build environment. This is only applicable
3935 to fixed-output derivations---i.e., when @var{hash} is true. The main
3936 use is to allow variables such as @code{http_proxy} to be passed to
3937 derivations that download files.
3939 When @var{local-build?} is true, declare that the derivation is not a
3940 good candidate for offloading and should rather be built locally
3941 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3942 where the costs of data transfers would outweigh the benefits.
3944 When @var{substitutable?} is false, declare that substitutes of the
3945 derivation's output should not be used (@pxref{Substitutes}). This is
3946 useful, for instance, when building packages that capture details of the
3947 host CPU instruction set.
3951 Here's an example with a shell script as its builder, assuming
3952 @var{store} is an open connection to the daemon, and @var{bash} points
3953 to a Bash executable in the store:
3956 (use-modules (guix utils)
3960 (let ((builder ; add the Bash script to the store
3961 (add-text-to-store store "my-builder.sh"
3962 "echo hello world > $out\n" '())))
3963 (derivation store "foo"
3964 bash `("-e" ,builder)
3965 #:inputs `((,bash) (,builder))
3966 #:env-vars '(("HOME" . "/homeless"))))
3967 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3970 As can be guessed, this primitive is cumbersome to use directly. A
3971 better approach is to write build scripts in Scheme, of course! The
3972 best course of action for that is to write the build code as a
3973 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3974 information, @pxref{G-Expressions}.
3976 Once upon a time, @code{gexp->derivation} did not exist and constructing
3977 derivations with build code written in Scheme was achieved with
3978 @code{build-expression->derivation}, documented below. This procedure
3979 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3981 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3982 @var{name} @var{exp} @
3983 [#:system (%current-system)] [#:inputs '()] @
3984 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3985 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3986 [#:references-graphs #f] [#:allowed-references #f] @
3987 [#:disallowed-references #f] @
3988 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3989 Return a derivation that executes Scheme expression @var{exp} as a
3990 builder for derivation @var{name}. @var{inputs} must be a list of
3991 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3992 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3993 modules from the current search path to be copied in the store,
3994 compiled, and made available in the load path during the execution of
3995 @var{exp}---e.g., @code{((guix build utils) (guix build
3996 gnu-build-system))}.
3998 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3999 to a list of output/path pairs, and where @code{%build-inputs} is bound
4000 to a list of string/output-path pairs made from @var{inputs}.
4001 Optionally, @var{env-vars} is a list of string pairs specifying the name
4002 and value of environment variables visible to the builder. The builder
4003 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4004 @var{exp} returns @code{#f}, the build is considered to have failed.
4006 @var{exp} is built using @var{guile-for-build} (a derivation). When
4007 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4008 @code{%guile-for-build} fluid is used instead.
4010 See the @code{derivation} procedure for the meaning of
4011 @var{references-graphs}, @var{allowed-references},
4012 @var{disallowed-references}, @var{local-build?}, and
4013 @var{substitutable?}.
4017 Here's an example of a single-output derivation that creates a directory
4018 containing one file:
4021 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4022 (mkdir out) ; create /gnu/store/@dots{}-goo
4023 (call-with-output-file (string-append out "/test")
4025 (display '(hello guix) p))))))
4026 (build-expression->derivation store "goo" builder))
4028 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4032 @node The Store Monad
4033 @section The Store Monad
4037 The procedures that operate on the store described in the previous
4038 sections all take an open connection to the build daemon as their first
4039 argument. Although the underlying model is functional, they either have
4040 side effects or depend on the current state of the store.
4042 The former is inconvenient: the connection to the build daemon has to be
4043 carried around in all those functions, making it impossible to compose
4044 functions that do not take that parameter with functions that do. The
4045 latter can be problematic: since store operations have side effects
4046 and/or depend on external state, they have to be properly sequenced.
4048 @cindex monadic values
4049 @cindex monadic functions
4050 This is where the @code{(guix monads)} module comes in. This module
4051 provides a framework for working with @dfn{monads}, and a particularly
4052 useful monad for our uses, the @dfn{store monad}. Monads are a
4053 construct that allows two things: associating ``context'' with values
4054 (in our case, the context is the store), and building sequences of
4055 computations (here computations include accesses to the store). Values
4056 in a monad---values that carry this additional context---are called
4057 @dfn{monadic values}; procedures that return such values are called
4058 @dfn{monadic procedures}.
4060 Consider this ``normal'' procedure:
4063 (define (sh-symlink store)
4064 ;; Return a derivation that symlinks the 'bash' executable.
4065 (let* ((drv (package-derivation store bash))
4066 (out (derivation->output-path drv))
4067 (sh (string-append out "/bin/bash")))
4068 (build-expression->derivation store "sh"
4069 `(symlink ,sh %output))))
4072 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4073 as a monadic function:
4076 (define (sh-symlink)
4077 ;; Same, but return a monadic value.
4078 (mlet %store-monad ((drv (package->derivation bash)))
4079 (gexp->derivation "sh"
4080 #~(symlink (string-append #$drv "/bin/bash")
4084 There are several things to note in the second version: the @code{store}
4085 parameter is now implicit and is ``threaded'' in the calls to the
4086 @code{package->derivation} and @code{gexp->derivation} monadic
4087 procedures, and the monadic value returned by @code{package->derivation}
4088 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4090 As it turns out, the call to @code{package->derivation} can even be
4091 omitted since it will take place implicitly, as we will see later
4092 (@pxref{G-Expressions}):
4095 (define (sh-symlink)
4096 (gexp->derivation "sh"
4097 #~(symlink (string-append #$bash "/bin/bash")
4102 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4103 @c for the funny quote.
4104 Calling the monadic @code{sh-symlink} has no effect. As someone once
4105 said, ``you exit a monad like you exit a building on fire: by running''.
4106 So, to exit the monad and get the desired effect, one must use
4107 @code{run-with-store}:
4110 (run-with-store (open-connection) (sh-symlink))
4111 @result{} /gnu/store/...-sh-symlink
4114 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4115 new ``meta-commands'' to make it easier to deal with monadic procedures:
4116 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4117 to ``run'' a single monadic value through the store:
4120 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4121 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4124 The latter enters a recursive REPL, where all the return values are
4125 automatically run through the store:
4128 scheme@@(guile-user)> ,enter-store-monad
4129 store-monad@@(guile-user) [1]> (package->derivation hello)
4130 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4131 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4132 $3 = "/gnu/store/@dots{}-foo"
4133 store-monad@@(guile-user) [1]> ,q
4134 scheme@@(guile-user)>
4138 Note that non-monadic values cannot be returned in the
4139 @code{store-monad} REPL.
4141 The main syntactic forms to deal with monads in general are provided by
4142 the @code{(guix monads)} module and are described below.
4144 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4145 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4149 @deffn {Scheme Syntax} return @var{val}
4150 Return a monadic value that encapsulates @var{val}.
4153 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4154 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4155 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4156 referred to as ``bind'', but that name denotes an unrelated procedure in
4157 Guile. Thus we use this somewhat cryptic symbol inherited from the
4158 Haskell language.}. There can be one @var{mproc} or several of them, as
4163 (with-monad %state-monad
4165 (lambda (x) (return (+ 1 x)))
4166 (lambda (x) (return (* 2 x)))))
4170 @result{} some-state
4174 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4176 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4178 Bind the variables @var{var} to the monadic values @var{mval} in
4179 @var{body}, which is a sequence of expressions. As with the bind
4180 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4181 value ``contained'' in @var{mval} and making @var{var} refer to that
4182 raw, non-monadic value within the scope of the @var{body}. The form
4183 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4184 @var{val}, as per @code{let}. The binding operations occur in sequence
4185 from left to right. The last expression of @var{body} must be a monadic
4186 expression, and its result will become the result of the @code{mlet} or
4187 @code{mlet*} when run in the @var{monad}.
4189 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4190 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4193 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4194 Bind @var{mexp} and the following monadic expressions in sequence,
4195 returning the result of the last expression. Every expression in the
4196 sequence must be a monadic expression.
4198 This is akin to @code{mlet}, except that the return values of the
4199 monadic expressions are ignored. In that sense, it is analogous to
4200 @code{begin}, but applied to monadic expressions.
4203 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4204 When @var{condition} is true, evaluate the sequence of monadic
4205 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4206 @var{condition} is false, return @code{*unspecified*} in the current
4207 monad. Every expression in the sequence must be a monadic expression.
4210 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4211 When @var{condition} is false, evaluate the sequence of monadic
4212 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4213 @var{condition} is true, return @code{*unspecified*} in the current
4214 monad. Every expression in the sequence must be a monadic expression.
4218 The @code{(guix monads)} module provides the @dfn{state monad}, which
4219 allows an additional value---the state---to be @emph{threaded} through
4220 monadic procedure calls.
4222 @defvr {Scheme Variable} %state-monad
4223 The state monad. Procedures in the state monad can access and change
4224 the state that is threaded.
4226 Consider the example below. The @code{square} procedure returns a value
4227 in the state monad. It returns the square of its argument, but also
4228 increments the current state value:
4232 (mlet %state-monad ((count (current-state)))
4233 (mbegin %state-monad
4234 (set-current-state (+ 1 count))
4237 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4242 When ``run'' through @var{%state-monad}, we obtain that additional state
4243 value, which is the number of @code{square} calls.
4246 @deffn {Monadic Procedure} current-state
4247 Return the current state as a monadic value.
4250 @deffn {Monadic Procedure} set-current-state @var{value}
4251 Set the current state to @var{value} and return the previous state as a
4255 @deffn {Monadic Procedure} state-push @var{value}
4256 Push @var{value} to the current state, which is assumed to be a list,
4257 and return the previous state as a monadic value.
4260 @deffn {Monadic Procedure} state-pop
4261 Pop a value from the current state and return it as a monadic value.
4262 The state is assumed to be a list.
4265 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4266 Run monadic value @var{mval} starting with @var{state} as the initial
4267 state. Return two values: the resulting value, and the resulting state.
4270 The main interface to the store monad, provided by the @code{(guix
4271 store)} module, is as follows.
4273 @defvr {Scheme Variable} %store-monad
4274 The store monad---an alias for @var{%state-monad}.
4276 Values in the store monad encapsulate accesses to the store. When its
4277 effect is needed, a value of the store monad must be ``evaluated'' by
4278 passing it to the @code{run-with-store} procedure (see below.)
4281 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4282 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4283 open store connection.
4286 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4287 Return as a monadic value the absolute file name in the store of the file
4288 containing @var{text}, a string. @var{references} is a list of store items that the
4289 resulting text file refers to; it defaults to the empty list.
4292 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4293 [#:recursive? #t] [#:select? (const #t)]
4294 Return the name of @var{file} once interned in the store. Use
4295 @var{name} as its store name, or the basename of @var{file} if
4296 @var{name} is omitted.
4298 When @var{recursive?} is true, the contents of @var{file} are added
4299 recursively; if @var{file} designates a flat file and @var{recursive?}
4300 is true, its contents are added, and its permission bits are kept.
4302 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4303 @var{stat})} for each directory entry, where @var{file} is the entry's
4304 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4305 entries for which @var{select?} does not return true.
4307 The example below adds a file to the store, under two different names:
4310 (run-with-store (open-connection)
4311 (mlet %store-monad ((a (interned-file "README"))
4312 (b (interned-file "README" "LEGU-MIN")))
4313 (return (list a b))))
4315 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4320 The @code{(guix packages)} module exports the following package-related
4323 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4324 [#:system (%current-system)] [#:target #f] @
4327 value in the absolute file name of @var{file} within the @var{output}
4328 directory of @var{package}. When @var{file} is omitted, return the name
4329 of the @var{output} directory of @var{package}. When @var{target} is
4330 true, use it as a cross-compilation target triplet.
4333 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4334 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4335 @var{target} [@var{system}]
4336 Monadic version of @code{package-derivation} and
4337 @code{package-cross-derivation} (@pxref{Defining Packages}).
4342 @section G-Expressions
4344 @cindex G-expression
4345 @cindex build code quoting
4346 So we have ``derivations'', which represent a sequence of build actions
4347 to be performed to produce an item in the store (@pxref{Derivations}).
4348 These build actions are performed when asking the daemon to actually
4349 build the derivations; they are run by the daemon in a container
4350 (@pxref{Invoking guix-daemon}).
4352 @cindex strata of code
4353 It should come as no surprise that we like to write these build actions
4354 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4355 code@footnote{The term @dfn{stratum} in this context was coined by
4356 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4357 Kiselyov, who has written insightful
4358 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4359 on this topic}, refers to this kind of code generation as
4360 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4361 to the daemon, etc.---and the ``build code''---code that actually
4362 performs build actions, such as making directories, invoking
4363 @command{make}, etc.
4365 To describe a derivation and its build actions, one typically needs to
4366 embed build code inside host code. It boils down to manipulating build
4367 code as data, and the homoiconicity of Scheme---code has a direct
4368 representation as data---comes in handy for that. But we need more than
4369 the normal @code{quasiquote} mechanism in Scheme to construct build
4372 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4373 S-expressions adapted to build expressions. G-expressions, or
4374 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4375 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4376 @code{#$}, and @code{#$@@}), which are comparable to
4377 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4378 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4379 GNU Guile Reference Manual}). However, there are major differences:
4383 Gexps are meant to be written to a file and run or manipulated by other
4387 When a high-level object such as a package or derivation is unquoted
4388 inside a gexp, the result is as if its output file name had been
4392 Gexps carry information about the packages or derivations they refer to,
4393 and these dependencies are automatically added as inputs to the build
4394 processes that use them.
4397 @cindex lowering, of high-level objects in gexps
4398 This mechanism is not limited to package and derivation
4399 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4400 derivations or files in the store can be defined,
4401 such that these objects can also be inserted
4402 into gexps. For example, a useful type of high-level objects that can be
4403 inserted in a gexp is ``file-like objects'', which make it easy to
4404 add files to the store and to refer to them in
4405 derivations and such (see @code{local-file} and @code{plain-file}
4408 To illustrate the idea, here is an example of a gexp:
4415 (symlink (string-append #$coreutils "/bin/ls")
4419 This gexp can be passed to @code{gexp->derivation}; we obtain a
4420 derivation that builds a directory containing exactly one symlink to
4421 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4424 (gexp->derivation "the-thing" build-exp)
4427 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4428 substituted to the reference to the @var{coreutils} package in the
4429 actual build code, and @var{coreutils} is automatically made an input to
4430 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4431 output)}) is replaced by a string containing the directory name of the
4432 output of the derivation.
4434 @cindex cross compilation
4435 In a cross-compilation context, it is useful to distinguish between
4436 references to the @emph{native} build of a package---that can run on the
4437 host---versus references to cross builds of a package. To that end, the
4438 @code{#+} plays the same role as @code{#$}, but is a reference to a
4439 native package build:
4442 (gexp->derivation "vi"
4445 (system* (string-append #+coreutils "/bin/ln")
4447 (string-append #$emacs "/bin/emacs")
4448 (string-append #$output "/bin/vi")))
4449 #:target "mips64el-linux-gnu")
4453 In the example above, the native build of @var{coreutils} is used, so
4454 that @command{ln} can actually run on the host; but then the
4455 cross-compiled build of @var{emacs} is referenced.
4457 @cindex imported modules, for gexps
4458 @findex with-imported-modules
4459 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4460 able to use certain Guile modules from the ``host environment'' in the
4461 gexp, so those modules should be imported in the ``build environment''.
4462 The @code{with-imported-modules} form allows you to express that:
4465 (let ((build (with-imported-modules '((guix build utils))
4467 (use-modules (guix build utils))
4468 (mkdir-p (string-append #$output "/bin"))))))
4469 (gexp->derivation "empty-dir"
4472 (display "success!\n")
4477 In this example, the @code{(guix build utils)} module is automatically
4478 pulled into the isolated build environment of our gexp, such that
4479 @code{(use-modules (guix build utils))} works as expected.
4481 @cindex module closure
4482 @findex source-module-closure
4483 Usually you want the @emph{closure} of the module to be imported---i.e.,
4484 the module itself and all the modules it depends on---rather than just
4485 the module; failing to do that, attempts to use the module will fail
4486 because of missing dependent modules. The @code{source-module-closure}
4487 procedure computes the closure of a module by looking at its source file
4488 headers, which comes in handy in this case:
4491 (use-modules (guix modules)) ;for 'source-module-closure'
4493 (with-imported-modules (source-module-closure
4494 '((guix build utils)
4496 (gexp->derivation "something-with-vms"
4498 (use-modules (guix build utils)
4503 The syntactic form to construct gexps is summarized below.
4505 @deffn {Scheme Syntax} #~@var{exp}
4506 @deffnx {Scheme Syntax} (gexp @var{exp})
4507 Return a G-expression containing @var{exp}. @var{exp} may contain one
4508 or more of the following forms:
4512 @itemx (ungexp @var{obj})
4513 Introduce a reference to @var{obj}. @var{obj} may have one of the
4514 supported types, for example a package or a
4515 derivation, in which case the @code{ungexp} form is replaced by its
4516 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4518 If @var{obj} is a list, it is traversed and references to supported
4519 objects are substituted similarly.
4521 If @var{obj} is another gexp, its contents are inserted and its
4522 dependencies are added to those of the containing gexp.
4524 If @var{obj} is another kind of object, it is inserted as is.
4526 @item #$@var{obj}:@var{output}
4527 @itemx (ungexp @var{obj} @var{output})
4528 This is like the form above, but referring explicitly to the
4529 @var{output} of @var{obj}---this is useful when @var{obj} produces
4530 multiple outputs (@pxref{Packages with Multiple Outputs}).
4533 @itemx #+@var{obj}:output
4534 @itemx (ungexp-native @var{obj})
4535 @itemx (ungexp-native @var{obj} @var{output})
4536 Same as @code{ungexp}, but produces a reference to the @emph{native}
4537 build of @var{obj} when used in a cross compilation context.
4539 @item #$output[:@var{output}]
4540 @itemx (ungexp output [@var{output}])
4541 Insert a reference to derivation output @var{output}, or to the main
4542 output when @var{output} is omitted.
4544 This only makes sense for gexps passed to @code{gexp->derivation}.
4547 @itemx (ungexp-splicing @var{lst})
4548 Like the above, but splices the contents of @var{lst} inside the
4552 @itemx (ungexp-native-splicing @var{lst})
4553 Like the above, but refers to native builds of the objects listed in
4558 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4559 of the @code{gexp?} type (see below.)
4562 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4563 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4564 in their execution environment.
4566 Each item in @var{modules} can be the name of a module, such as
4567 @code{(guix build utils)}, or it can be a module name, followed by an
4568 arrow, followed by a file-like object:
4571 `((guix build utils)
4573 ((guix config) => ,(scheme-file "config.scm"
4574 #~(define-module @dots{}))))
4578 In the example above, the first two modules are taken from the search
4579 path, and the last one is created from the given file-like object.
4581 This form has @emph{lexical} scope: it has an effect on the gexps
4582 directly defined in @var{body}@dots{}, but not on those defined, say, in
4583 procedures called from @var{body}@dots{}.
4586 @deffn {Scheme Procedure} gexp? @var{obj}
4587 Return @code{#t} if @var{obj} is a G-expression.
4590 G-expressions are meant to be written to disk, either as code building
4591 some derivation, or as plain files in the store. The monadic procedures
4592 below allow you to do that (@pxref{The Store Monad}, for more
4593 information about monads.)
4595 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4596 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4597 [#:hash #f] [#:hash-algo #f] @
4598 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4599 [#:module-path @var{%load-path}] @
4600 [#:references-graphs #f] [#:allowed-references #f] @
4601 [#:disallowed-references #f] @
4602 [#:leaked-env-vars #f] @
4603 [#:script-name (string-append @var{name} "-builder")] @
4604 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4605 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4606 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4607 stored in a file called @var{script-name}. When @var{target} is true,
4608 it is used as the cross-compilation target triplet for packages referred
4611 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4613 make @var{modules} available in the evaluation context of @var{exp};
4614 @var{modules} is a list of names of Guile modules searched in
4615 @var{module-path} to be copied in the store, compiled, and made available in
4616 the load path during the execution of @var{exp}---e.g., @code{((guix
4617 build utils) (guix build gnu-build-system))}.
4619 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4622 When @var{references-graphs} is true, it must be a list of tuples of one of the
4626 (@var{file-name} @var{package})
4627 (@var{file-name} @var{package} @var{output})
4628 (@var{file-name} @var{derivation})
4629 (@var{file-name} @var{derivation} @var{output})
4630 (@var{file-name} @var{store-item})
4633 The right-hand-side of each element of @var{references-graphs} is automatically made
4634 an input of the build process of @var{exp}. In the build environment, each
4635 @var{file-name} contains the reference graph of the corresponding item, in a simple
4638 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4639 In the latter case, the list denotes store items that the result is allowed to
4640 refer to. Any reference to another store item will lead to a build error.
4641 Similarly for @var{disallowed-references}, which can list items that must not be
4642 referenced by the outputs.
4644 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4647 @cindex file-like objects
4648 The @code{local-file}, @code{plain-file}, @code{computed-file},
4649 @code{program-file}, and @code{scheme-file} procedures below return
4650 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4651 these objects lead to a file in the store. Consider this G-expression:
4654 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4655 #$(local-file "/tmp/my-nscd.conf"))
4658 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4659 to the store. Once expanded, for instance @i{via}
4660 @code{gexp->derivation}, the G-expression refers to that copy under
4661 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4662 does not have any effect on what the G-expression does.
4663 @code{plain-file} can be used similarly; it differs in that the file
4664 content is directly passed as a string.
4666 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4667 [#:recursive? #f] [#:select? (const #t)]
4668 Return an object representing local file @var{file} to add to the store; this
4669 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4670 up relative to the source file where this form appears. @var{file} will be added to
4671 the store under @var{name}--by default the base name of @var{file}.
4673 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4674 designates a flat file and @var{recursive?} is true, its contents are added, and its
4675 permission bits are kept.
4677 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4678 @var{stat})} for each directory entry, where @var{file} is the entry's
4679 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4680 entries for which @var{select?} does not return true.
4682 This is the declarative counterpart of the @code{interned-file} monadic
4683 procedure (@pxref{The Store Monad, @code{interned-file}}).
4686 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4687 Return an object representing a text file called @var{name} with the given
4688 @var{content} (a string) to be added to the store.
4690 This is the declarative counterpart of @code{text-file}.
4693 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4694 [#:options '(#:local-build? #t)]
4695 Return an object representing the store item @var{name}, a file or
4696 directory computed by @var{gexp}. @var{options}
4697 is a list of additional arguments to pass to @code{gexp->derivation}.
4699 This is the declarative counterpart of @code{gexp->derivation}.
4702 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4703 Return an executable script @var{name} that runs @var{exp} using
4704 @var{guile}, with @var{exp}'s imported modules in its search path.
4706 The example below builds a script that simply invokes the @command{ls}
4710 (use-modules (guix gexp) (gnu packages base))
4712 (gexp->script "list-files"
4713 #~(execl #$(file-append coreutils "/bin/ls")
4717 When ``running'' it through the store (@pxref{The Store Monad,
4718 @code{run-with-store}}), we obtain a derivation that produces an
4719 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4722 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4724 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4728 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4730 Return an object representing the executable store item @var{name} that
4731 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4734 This is the declarative counterpart of @code{gexp->script}.
4737 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4738 [#:set-load-path? #t]
4739 Return a derivation that builds a file @var{name} containing @var{exp}.
4740 When @var{set-load-path?} is true, emit code in the resulting file to
4741 set @code{%load-path} and @code{%load-compiled-path} to honor
4742 @var{exp}'s imported modules.
4744 The resulting file holds references to all the dependencies of @var{exp}
4745 or a subset thereof.
4748 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4749 Return an object representing the Scheme file @var{name} that contains
4752 This is the declarative counterpart of @code{gexp->file}.
4755 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4756 Return as a monadic value a derivation that builds a text file
4757 containing all of @var{text}. @var{text} may list, in addition to
4758 strings, objects of any type that can be used in a gexp: packages,
4759 derivations, local file objects, etc. The resulting store file holds
4760 references to all these.
4762 This variant should be preferred over @code{text-file} anytime the file
4763 to create will reference items from the store. This is typically the
4764 case when building a configuration file that embeds store file names,
4768 (define (profile.sh)
4769 ;; Return the name of a shell script in the store that
4770 ;; initializes the 'PATH' environment variable.
4771 (text-file* "profile.sh"
4772 "export PATH=" coreutils "/bin:"
4773 grep "/bin:" sed "/bin\n"))
4776 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4777 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4778 preventing them from being garbage-collected during its lifetime.
4781 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4782 Return an object representing store file @var{name} containing
4783 @var{text}. @var{text} is a sequence of strings and file-like objects,
4787 (mixed-text-file "profile"
4788 "export PATH=" coreutils "/bin:" grep "/bin")
4791 This is the declarative counterpart of @code{text-file*}.
4794 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4795 Return a file-like object that expands to the concatenation of @var{obj}
4796 and @var{suffix}, where @var{obj} is a lowerable object and each
4797 @var{suffix} is a string.
4799 As an example, consider this gexp:
4802 (gexp->script "run-uname"
4803 #~(system* #$(file-append coreutils
4807 The same effect could be achieved with:
4810 (gexp->script "run-uname"
4811 #~(system* (string-append #$coreutils
4815 There is one difference though: in the @code{file-append} case, the
4816 resulting script contains the absolute file name as a string, whereas in
4817 the second case, the resulting script contains a @code{(string-append
4818 @dots{})} expression to construct the file name @emph{at run time}.
4822 Of course, in addition to gexps embedded in ``host'' code, there are
4823 also modules containing build tools. To make it clear that they are
4824 meant to be used in the build stratum, these modules are kept in the
4825 @code{(guix build @dots{})} name space.
4827 @cindex lowering, of high-level objects in gexps
4828 Internally, high-level objects are @dfn{lowered}, using their compiler,
4829 to either derivations or store items. For instance, lowering a package
4830 yields a derivation, and lowering a @code{plain-file} yields a store
4831 item. This is achieved using the @code{lower-object} monadic procedure.
4833 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4835 Return as a value in @var{%store-monad} the derivation or store item
4836 corresponding to @var{obj} for @var{system}, cross-compiling for
4837 @var{target} if @var{target} is true. @var{obj} must be an object that
4838 has an associated gexp compiler, such as a @code{<package>}.
4842 @c *********************************************************************
4846 This section describes Guix command-line utilities. Some of them are
4847 primarily targeted at developers and users who write new package
4848 definitions, while others are more generally useful. They complement
4849 the Scheme programming interface of Guix in a convenient way.
4852 * Invoking guix build:: Building packages from the command line.
4853 * Invoking guix edit:: Editing package definitions.
4854 * Invoking guix download:: Downloading a file and printing its hash.
4855 * Invoking guix hash:: Computing the cryptographic hash of a file.
4856 * Invoking guix import:: Importing package definitions.
4857 * Invoking guix refresh:: Updating package definitions.
4858 * Invoking guix lint:: Finding errors in package definitions.
4859 * Invoking guix size:: Profiling disk usage.
4860 * Invoking guix graph:: Visualizing the graph of packages.
4861 * Invoking guix environment:: Setting up development environments.
4862 * Invoking guix publish:: Sharing substitutes.
4863 * Invoking guix challenge:: Challenging substitute servers.
4864 * Invoking guix copy:: Copying to and from a remote store.
4865 * Invoking guix container:: Process isolation.
4868 @node Invoking guix build
4869 @section Invoking @command{guix build}
4871 @cindex package building
4872 @cindex @command{guix build}
4873 The @command{guix build} command builds packages or derivations and
4874 their dependencies, and prints the resulting store paths. Note that it
4875 does not modify the user's profile---this is the job of the
4876 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4877 it is mainly useful for distribution developers.
4879 The general syntax is:
4882 guix build @var{options} @var{package-or-derivation}@dots{}
4885 As an example, the following command builds the latest versions of Emacs
4886 and of Guile, displays their build logs, and finally displays the
4887 resulting directories:
4890 guix build emacs guile
4893 Similarly, the following command builds all the available packages:
4896 guix build --quiet --keep-going \
4897 `guix package -A | cut -f1,2 --output-delimiter=@@`
4900 @var{package-or-derivation} may be either the name of a package found in
4901 the software distribution such as @code{coreutils} or
4902 @code{coreutils@@8.20}, or a derivation such as
4903 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4904 package with the corresponding name (and optionally version) is searched
4905 for among the GNU distribution modules (@pxref{Package Modules}).
4907 Alternatively, the @code{--expression} option may be used to specify a
4908 Scheme expression that evaluates to a package; this is useful when
4909 disambiguating among several same-named packages or package variants is
4912 There may be zero or more @var{options}. The available options are
4913 described in the subsections below.
4916 * Common Build Options:: Build options for most commands.
4917 * Package Transformation Options:: Creating variants of packages.
4918 * Additional Build Options:: Options specific to 'guix build'.
4919 * Debugging Build Failures:: Real life packaging experience.
4922 @node Common Build Options
4923 @subsection Common Build Options
4925 A number of options that control the build process are common to
4926 @command{guix build} and other commands that can spawn builds, such as
4927 @command{guix package} or @command{guix archive}. These are the
4932 @item --load-path=@var{directory}
4933 @itemx -L @var{directory}
4934 Add @var{directory} to the front of the package module search path
4935 (@pxref{Package Modules}).
4937 This allows users to define their own packages and make them visible to
4938 the command-line tools.
4942 Keep the build tree of failed builds. Thus, if a build fails, its build
4943 tree is kept under @file{/tmp}, in a directory whose name is shown at
4944 the end of the build log. This is useful when debugging build issues.
4945 @xref{Debugging Build Failures}, for tips and tricks on how to debug
4950 Keep going when some of the derivations fail to build; return only once
4951 all the builds have either completed or failed.
4953 The default behavior is to stop as soon as one of the specified
4954 derivations has failed.
4958 Do not build the derivations.
4961 When substituting a pre-built binary fails, fall back to building
4964 @item --substitute-urls=@var{urls}
4965 @anchor{client-substitute-urls}
4966 Consider @var{urls} the whitespace-separated list of substitute source
4967 URLs, overriding the default list of URLs of @command{guix-daemon}
4968 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4970 This means that substitutes may be downloaded from @var{urls}, provided
4971 they are signed by a key authorized by the system administrator
4972 (@pxref{Substitutes}).
4974 When @var{urls} is the empty string, substitutes are effectively
4977 @item --no-substitutes
4978 Do not use substitutes for build products. That is, always build things
4979 locally instead of allowing downloads of pre-built binaries
4980 (@pxref{Substitutes}).
4983 Do not ``graft'' packages. In practice, this means that package updates
4984 available as grafts are not applied. @xref{Security Updates}, for more
4985 information on grafts.
4987 @item --rounds=@var{n}
4988 Build each derivation @var{n} times in a row, and raise an error if
4989 consecutive build results are not bit-for-bit identical.
4991 This is a useful way to detect non-deterministic builds processes.
4992 Non-deterministic build processes are a problem because they make it
4993 practically impossible for users to @emph{verify} whether third-party
4994 binaries are genuine. @xref{Invoking guix challenge}, for more.
4996 Note that, currently, the differing build results are not kept around,
4997 so you will have to manually investigate in case of an error---e.g., by
4998 stashing one of the build results with @code{guix archive --export}
4999 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5002 @item --no-build-hook
5003 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5004 (@pxref{Daemon Offload Setup}). That is, always build things locally
5005 instead of offloading builds to remote machines.
5007 @item --max-silent-time=@var{seconds}
5008 When the build or substitution process remains silent for more than
5009 @var{seconds}, terminate it and report a build failure.
5011 By default, the daemon's setting is honored (@pxref{Invoking
5012 guix-daemon, @code{--max-silent-time}}).
5014 @item --timeout=@var{seconds}
5015 Likewise, when the build or substitution process lasts for more than
5016 @var{seconds}, terminate it and report a build failure.
5018 By default, the daemon's setting is honored (@pxref{Invoking
5019 guix-daemon, @code{--timeout}}).
5021 @item --verbosity=@var{level}
5022 Use the given verbosity level. @var{level} must be an integer between 0
5023 and 5; higher means more verbose output. Setting a level of 4 or more
5024 may be helpful when debugging setup issues with the build daemon.
5026 @item --cores=@var{n}
5028 Allow the use of up to @var{n} CPU cores for the build. The special
5029 value @code{0} means to use as many CPU cores as available.
5031 @item --max-jobs=@var{n}
5033 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5034 guix-daemon, @code{--max-jobs}}, for details about this option and the
5035 equivalent @command{guix-daemon} option.
5039 Behind the scenes, @command{guix build} is essentially an interface to
5040 the @code{package-derivation} procedure of the @code{(guix packages)}
5041 module, and to the @code{build-derivations} procedure of the @code{(guix
5042 derivations)} module.
5044 In addition to options explicitly passed on the command line,
5045 @command{guix build} and other @command{guix} commands that support
5046 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5048 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5049 Users can define this variable to a list of command line options that
5050 will automatically be used by @command{guix build} and other
5051 @command{guix} commands that can perform builds, as in the example
5055 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5058 These options are parsed independently, and the result is appended to
5059 the parsed command-line options.
5063 @node Package Transformation Options
5064 @subsection Package Transformation Options
5066 @cindex package variants
5067 Another set of command-line options supported by @command{guix build}
5068 and also @command{guix package} are @dfn{package transformation
5069 options}. These are options that make it possible to define @dfn{package
5070 variants}---for instance, packages built from different source code.
5071 This is a convenient way to create customized packages on the fly
5072 without having to type in the definitions of package variants
5073 (@pxref{Defining Packages}).
5077 @item --with-source=@var{source}
5078 Use @var{source} as the source of the corresponding package.
5079 @var{source} must be a file name or a URL, as for @command{guix
5080 download} (@pxref{Invoking guix download}).
5082 The ``corresponding package'' is taken to be the one specified on the
5083 command line the name of which matches the base of @var{source}---e.g.,
5084 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5085 package is @code{guile}. Likewise, the version string is inferred from
5086 @var{source}; in the previous example, it is @code{2.0.10}.
5088 This option allows users to try out versions of packages other than the
5089 one provided by the distribution. The example below downloads
5090 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5091 the @code{ed} package:
5094 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5097 As a developer, @code{--with-source} makes it easy to test release
5101 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5104 @dots{} or to build from a checkout in a pristine environment:
5107 $ git clone git://git.sv.gnu.org/guix.git
5108 $ guix build guix --with-source=./guix
5111 @item --with-input=@var{package}=@var{replacement}
5112 Replace dependency on @var{package} by a dependency on
5113 @var{replacement}. @var{package} must be a package name, and
5114 @var{replacement} must be a package specification such as @code{guile}
5115 or @code{guile@@1.8}.
5117 For instance, the following command builds Guix, but replaces its
5118 dependency on the current stable version of Guile with a dependency on
5119 the legacy version of Guile, @code{guile@@2.0}:
5122 guix build --with-input=guile=guile@@2.0 guix
5125 This is a recursive, deep replacement. So in this example, both
5126 @code{guix} and its dependency @code{guile-json} (which also depends on
5127 @code{guile}) get rebuilt against @code{guile@@2.0}.
5129 This is implemented using the @code{package-input-rewriting} Scheme
5130 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5132 @item --with-graft=@var{package}=@var{replacement}
5133 This is similar to @code{--with-input} but with an important difference:
5134 instead of rebuilding the whole dependency chain, @var{replacement} is
5135 built and then @dfn{grafted} onto the binaries that were initially
5136 referring to @var{package}. @xref{Security Updates}, for more
5137 information on grafts.
5139 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5140 and all its dependencies, replacing references to the version of GnuTLS
5141 they currently refer to:
5144 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5147 This has the advantage of being much faster than rebuilding everything.
5148 But there is a caveat: it works if and only if @var{package} and
5149 @var{replacement} are strictly compatible---for example, if they provide
5150 a library, the application binary interface (ABI) of those libraries
5151 must be compatible. If @var{replacement} is somehow incompatible with
5152 @var{package}, then the resulting package may be unusable. Use with
5157 @node Additional Build Options
5158 @subsection Additional Build Options
5160 The command-line options presented below are specific to @command{guix
5167 Build quietly, without displaying the build log. Upon completion, the
5168 build log is kept in @file{/var} (or similar) and can always be
5169 retrieved using the @option{--log-file} option.
5171 @item --file=@var{file}
5172 @itemx -f @var{file}
5174 Build the package or derivation that the code within @var{file}
5177 As an example, @var{file} might contain a package definition like this
5178 (@pxref{Defining Packages}):
5181 @verbatiminclude package-hello.scm
5184 @item --expression=@var{expr}
5185 @itemx -e @var{expr}
5186 Build the package or derivation @var{expr} evaluates to.
5188 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5189 guile-1.8)}, which unambiguously designates this specific variant of
5190 version 1.8 of Guile.
5192 Alternatively, @var{expr} may be a G-expression, in which case it is used
5193 as a build program passed to @code{gexp->derivation}
5194 (@pxref{G-Expressions}).
5196 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5197 (@pxref{The Store Monad}). The procedure must return a derivation as a
5198 monadic value, which is then passed through @code{run-with-store}.
5202 Build the source derivations of the packages, rather than the packages
5205 For instance, @code{guix build -S gcc} returns something like
5206 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5209 The returned source tarball is the result of applying any patches and
5210 code snippets specified in the package @code{origin} (@pxref{Defining
5214 Fetch and return the source of @var{package-or-derivation} and all their
5215 dependencies, recursively. This is a handy way to obtain a local copy
5216 of all the source code needed to build @var{packages}, allowing you to
5217 eventually build them even without network access. It is an extension
5218 of the @code{--source} option and can accept one of the following
5219 optional argument values:
5223 This value causes the @code{--sources} option to behave in the same way
5224 as the @code{--source} option.
5227 Build the source derivations of all packages, including any source that
5228 might be listed as @code{inputs}. This is the default value.
5231 $ guix build --sources tzdata
5232 The following derivations will be built:
5233 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5234 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5238 Build the source derivations of all packages, as well of all transitive
5239 inputs to the packages. This can be used e.g. to
5240 prefetch package source for later offline building.
5243 $ guix build --sources=transitive tzdata
5244 The following derivations will be built:
5245 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5246 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5247 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5248 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5249 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5250 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5256 @item --system=@var{system}
5257 @itemx -s @var{system}
5258 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5259 the system type of the build host.
5261 An example use of this is on Linux-based systems, which can emulate
5262 different personalities. For instance, passing
5263 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5264 to build packages in a complete 32-bit environment.
5266 @item --target=@var{triplet}
5267 @cindex cross-compilation
5268 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5269 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5270 configuration triplets,, autoconf, Autoconf}).
5272 @anchor{build-check}
5274 @cindex determinism, checking
5275 @cindex reproducibility, checking
5276 Rebuild @var{package-or-derivation}, which are already available in the
5277 store, and raise an error if the build results are not bit-for-bit
5280 This mechanism allows you to check whether previously installed
5281 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5282 of a package is deterministic. @xref{Invoking guix challenge}, for more
5283 background information and tools.
5285 When used in conjunction with @option{--keep-failed}, the differing
5286 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5287 This makes it easy to look for differences between the two results.
5290 @cindex repairing store items
5291 @cindex corruption, recovering from
5292 Attempt to repair the specified store items, if they are corrupt, by
5293 re-downloading or rebuilding them.
5295 This operation is not atomic and thus restricted to @code{root}.
5299 Return the derivation paths, not the output paths, of the given
5302 @item --root=@var{file}
5303 @itemx -r @var{file}
5304 Make @var{file} a symlink to the result, and register it as a garbage
5308 Return the build log file names or URLs for the given
5309 @var{package-or-derivation}, or raise an error if build logs are
5312 This works regardless of how packages or derivations are specified. For
5313 instance, the following invocations are equivalent:
5316 guix build --log-file `guix build -d guile`
5317 guix build --log-file `guix build guile`
5318 guix build --log-file guile
5319 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5322 If a log is unavailable locally, and unless @code{--no-substitutes} is
5323 passed, the command looks for a corresponding log on one of the
5324 substitute servers (as specified with @code{--substitute-urls}.)
5326 So for instance, imagine you want to see the build log of GDB on MIPS,
5327 but you are actually on an @code{x86_64} machine:
5330 $ guix build --log-file gdb -s mips64el-linux
5331 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5334 You can freely access a huge library of build logs!
5337 @node Debugging Build Failures
5338 @subsection Debugging Build Failures
5340 @cindex build failures, debugging
5341 When defining a new package (@pxref{Defining Packages}), you will
5342 probably find yourself spending some time debugging and tweaking the
5343 build until it succeeds. To do that, you need to operate the build
5344 commands yourself in an environment as close as possible to the one the
5347 To that end, the first thing to do is to use the @option{--keep-failed}
5348 or @option{-K} option of @command{guix build}, which will keep the
5349 failed build tree in @file{/tmp} or whatever directory you specified as
5350 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5352 From there on, you can @command{cd} to the failed build tree and source
5353 the @file{environment-variables} file, which contains all the
5354 environment variable definitions that were in place when the build
5355 failed. So let's say you're debugging a build failure in package
5356 @code{foo}; a typical session would look like this:
5360 @dots{} @i{build fails}
5361 $ cd /tmp/guix-build-foo.drv-0
5362 $ source ./environment-variables
5366 Now, you can invoke commands as if you were the daemon (almost) and
5367 troubleshoot your build process.
5369 Sometimes it happens that, for example, a package's tests pass when you
5370 run them manually but they fail when the daemon runs them. This can
5371 happen because the daemon runs builds in containers where, unlike in our
5372 environment above, network access is missing, @file{/bin/sh} does not
5373 exist, etc. (@pxref{Build Environment Setup}).
5375 In such cases, you may need to run inspect the build process from within
5376 a container similar to the one the build daemon creates:
5381 $ cd /tmp/guix-build-foo.drv-0
5382 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5383 [env]# source ./environment-variables
5387 Here, @command{guix environment -C} creates a container and spawns a new
5388 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5389 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5390 the container, which would may find handy while debugging. The
5391 @option{--no-grafts} option makes sure we get the exact same
5392 environment, with ungrafted packages (@pxref{Security Updates}, for more
5395 To get closer to a container like that used by the build daemon, we can
5396 remove @file{/bin/sh}:
5402 (Don't worry, this is harmless: this is all happening in the throw-away
5403 container created by @command{guix environment}.)
5405 The @command{strace} command is probably not in the search path, but we
5409 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5412 In this way, not only you will have reproduced the environment variables
5413 the daemon uses, you will also be running the build process in a container
5414 similar to the one the daemon uses.
5417 @node Invoking guix edit
5418 @section Invoking @command{guix edit}
5420 @cindex @command{guix edit}
5421 @cindex package definition, editing
5422 So many packages, so many source files! The @command{guix edit} command
5423 facilitates the life of users and packagers by pointing their editor at
5424 the source file containing the definition of the specified packages.
5428 guix edit gcc@@4.9 vim
5432 launches the program specified in the @code{VISUAL} or in the
5433 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5436 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5437 have created your own packages on @code{GUIX_PACKAGE_PATH}
5438 (@pxref{Defining Packages}), you will be able to edit the package
5439 recipes. Otherwise, you will be able to examine the read-only recipes
5440 for packages currently in the store.
5443 @node Invoking guix download
5444 @section Invoking @command{guix download}
5446 @cindex @command{guix download}
5447 @cindex downloading package sources
5448 When writing a package definition, developers typically need to download
5449 a source tarball, compute its SHA256 hash, and write that
5450 hash in the package definition (@pxref{Defining Packages}). The
5451 @command{guix download} tool helps with this task: it downloads a file
5452 from the given URI, adds it to the store, and prints both its file name
5453 in the store and its SHA256 hash.
5455 The fact that the downloaded file is added to the store saves bandwidth:
5456 when the developer eventually tries to build the newly defined package
5457 with @command{guix build}, the source tarball will not have to be
5458 downloaded again because it is already in the store. It is also a
5459 convenient way to temporarily stash files, which may be deleted
5460 eventually (@pxref{Invoking guix gc}).
5462 The @command{guix download} command supports the same URIs as used in
5463 package definitions. In particular, it supports @code{mirror://} URIs.
5464 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5465 Guile bindings for GnuTLS are available in the user's environment; when
5466 they are not available, an error is raised. @xref{Guile Preparations,
5467 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5468 GnuTLS-Guile}, for more information.
5470 @command{guix download} verifies HTTPS server certificates by loading
5471 the certificates of X.509 authorities from the directory pointed to by
5472 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5473 Certificates}), unless @option{--no-check-certificate} is used.
5475 The following options are available:
5478 @item --format=@var{fmt}
5480 Write the hash in the format specified by @var{fmt}. For more
5481 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5483 @item --no-check-certificate
5484 Do not validate the X.509 certificates of HTTPS servers.
5486 When using this option, you have @emph{absolutely no guarantee} that you
5487 are communicating with the authentic server responsible for the given
5488 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5490 @item --output=@var{file}
5491 @itemx -o @var{file}
5492 Save the downloaded file to @var{file} instead of adding it to the
5496 @node Invoking guix hash
5497 @section Invoking @command{guix hash}
5499 @cindex @command{guix hash}
5500 The @command{guix hash} command computes the SHA256 hash of a file.
5501 It is primarily a convenience tool for anyone contributing to the
5502 distribution: it computes the cryptographic hash of a file, which can be
5503 used in the definition of a package (@pxref{Defining Packages}).
5505 The general syntax is:
5508 guix hash @var{option} @var{file}
5511 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5512 hash of data read from standard input. @command{guix hash} has the
5517 @item --format=@var{fmt}
5519 Write the hash in the format specified by @var{fmt}.
5521 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5522 (@code{hex} and @code{hexadecimal} can be used as well).
5524 If the @option{--format} option is not specified, @command{guix hash}
5525 will output the hash in @code{nix-base32}. This representation is used
5526 in the definitions of packages.
5530 Compute the hash on @var{file} recursively.
5532 In this case, the hash is computed on an archive containing @var{file},
5533 including its children if it is a directory. Some of the metadata of
5534 @var{file} is part of the archive; for instance, when @var{file} is a
5535 regular file, the hash is different depending on whether @var{file} is
5536 executable or not. Metadata such as time stamps has no impact on the
5537 hash (@pxref{Invoking guix archive}).
5538 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5543 When combined with @option{--recursive}, exclude version control system
5544 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5547 As an example, here is how you would compute the hash of a Git checkout,
5548 which is useful when using the @code{git-fetch} method (@pxref{origin
5552 $ git clone http://example.org/foo.git
5558 @node Invoking guix import
5559 @section Invoking @command{guix import}
5561 @cindex importing packages
5562 @cindex package import
5563 @cindex package conversion
5564 @cindex Invoking @command{guix import}
5565 The @command{guix import} command is useful for people who would like to
5566 add a package to the distribution with as little work as
5567 possible---a legitimate demand. The command knows of a few
5568 repositories from which it can ``import'' package metadata. The result
5569 is a package definition, or a template thereof, in the format we know
5570 (@pxref{Defining Packages}).
5572 The general syntax is:
5575 guix import @var{importer} @var{options}@dots{}
5578 @var{importer} specifies the source from which to import package
5579 metadata, and @var{options} specifies a package identifier and other
5580 options specific to @var{importer}. Currently, the available
5585 Import metadata for the given GNU package. This provides a template
5586 for the latest version of that GNU package, including the hash of its
5587 source tarball, and its canonical synopsis and description.
5589 Additional information such as the package dependencies and its
5590 license needs to be figured out manually.
5592 For example, the following command returns a package definition for
5596 guix import gnu hello
5599 Specific command-line options are:
5602 @item --key-download=@var{policy}
5603 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5604 keys when verifying the package signature. @xref{Invoking guix
5605 refresh, @code{--key-download}}.
5610 Import metadata from the @uref{https://pypi.python.org/, Python Package
5611 Index}@footnote{This functionality requires Guile-JSON to be installed.
5612 @xref{Requirements}.}. Information is taken from the JSON-formatted
5613 description available at @code{pypi.python.org} and usually includes all
5614 the relevant information, including package dependencies. For maximum
5615 efficiency, it is recommended to install the @command{unzip} utility, so
5616 that the importer can unzip Python wheels and gather data from them.
5618 The command below imports metadata for the @code{itsdangerous} Python
5622 guix import pypi itsdangerous
5627 Import metadata from @uref{https://rubygems.org/,
5628 RubyGems}@footnote{This functionality requires Guile-JSON to be
5629 installed. @xref{Requirements}.}. Information is taken from the
5630 JSON-formatted description available at @code{rubygems.org} and includes
5631 most relevant information, including runtime dependencies. There are
5632 some caveats, however. The metadata doesn't distinguish between
5633 synopses and descriptions, so the same string is used for both fields.
5634 Additionally, the details of non-Ruby dependencies required to build
5635 native extensions is unavailable and left as an exercise to the
5638 The command below imports metadata for the @code{rails} Ruby package:
5641 guix import gem rails
5646 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5647 functionality requires Guile-JSON to be installed.
5648 @xref{Requirements}.}.
5649 Information is taken from the JSON-formatted metadata provided through
5650 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5651 relevant information, such as module dependencies. License information
5652 should be checked closely. If Perl is available in the store, then the
5653 @code{corelist} utility will be used to filter core modules out of the
5654 list of dependencies.
5656 The command command below imports metadata for the @code{Acme::Boolean}
5660 guix import cpan Acme::Boolean
5665 @cindex Bioconductor
5666 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5667 central repository for the @uref{http://r-project.org, GNU@tie{}R
5668 statistical and graphical environment}.
5670 Information is extracted from the @code{DESCRIPTION} file of the package.
5672 The command command below imports metadata for the @code{Cairo}
5676 guix import cran Cairo
5679 When @code{--recursive} is added, the importer will traverse the
5680 dependency graph of the given upstream package recursively and generate
5681 package expressions for all those packages that are not yet in Guix.
5683 When @code{--archive=bioconductor} is added, metadata is imported from
5684 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5685 packages for for the analysis and comprehension of high-throughput
5686 genomic data in bioinformatics.
5688 Information is extracted from the @code{DESCRIPTION} file of a package
5689 published on the web interface of the Bioconductor SVN repository.
5691 The command below imports metadata for the @code{GenomicRanges}
5695 guix import cran --archive=bioconductor GenomicRanges
5701 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5702 comprehensive TeX archive network for TeX packages that are part of the
5703 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5705 Information about the package is obtained through the XML API provided
5706 by CTAN, while the source code is downloaded from the SVN repository of
5707 the Tex Live project. This is done because the CTAN does not keep
5710 The command command below imports metadata for the @code{fontspec}
5714 guix import texlive fontspec
5717 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5718 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5719 tree in the TeX Live SVN repository, but from the specified sibling
5720 directory under the same root.
5722 The command below imports metadata for the @code{ifxetex} package from
5723 CTAN while fetching the sources from the directory
5724 @file{texmf/source/generic}:
5727 guix import texlive --archive=generic ifxetex
5731 Import metadata from a local copy of the source of the
5732 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5733 relies on the @command{nix-instantiate} command of
5734 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5735 typically written in a mixture of Nix-language and Bash code. This
5736 command only imports the high-level package structure that is written in
5737 the Nix language. It normally includes all the basic fields of a
5740 When importing a GNU package, the synopsis and descriptions are replaced
5741 by their canonical upstream variant.
5743 Usually, you will first need to do:
5746 export NIX_REMOTE=daemon
5750 so that @command{nix-instantiate} does not try to open the Nix database.
5752 As an example, the command below imports the package definition of
5753 LibreOffice (more precisely, it imports the definition of the package
5754 bound to the @code{libreoffice} top-level attribute):
5757 guix import nix ~/path/to/nixpkgs libreoffice
5762 Import metadata from the Haskell community's central package archive
5763 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5764 Cabal files and includes all the relevant information, including package
5767 Specific command-line options are:
5772 Read a Cabal file from standard input.
5773 @item --no-test-dependencies
5775 Do not include dependencies required only by the test suites.
5776 @item --cabal-environment=@var{alist}
5777 @itemx -e @var{alist}
5778 @var{alist} is a Scheme alist defining the environment in which the
5779 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5780 @code{arch}, @code{impl} and a string representing the name of a flag.
5781 The value associated with a flag has to be either the symbol
5782 @code{true} or @code{false}. The value associated with other keys
5783 has to conform to the Cabal file format definition. The default value
5784 associated with the keys @code{os}, @code{arch} and @code{impl} is
5785 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5788 The command below imports metadata for the latest version of the
5789 @code{HTTP} Haskell package without including test dependencies and
5790 specifying the value of the flag @samp{network-uri} as @code{false}:
5793 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5796 A specific package version may optionally be specified by following the
5797 package name by an at-sign and a version number as in the following example:
5800 guix import hackage mtl@@2.1.3.1
5805 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5806 It takes a package name, looks up the package version included in a
5807 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5808 release and uses the @code{hackage} importer to retrieve its metadata.
5809 Note that it is up to you to select an LTS release compatible with the
5810 GHC compiler used by Guix.
5812 Specific command-line options are:
5815 @item --no-test-dependencies
5817 Do not include dependencies required only by the test suites.
5818 @item --lts-version=@var{version}
5819 @itemx -r @var{version}
5820 @var{version} is the desired LTS release version. If omitted the latest
5824 The command below imports metadata for the @code{HTTP} Haskell package
5825 included in the LTS Stackage release version 7.18:
5828 guix import stackage --lts-version=7.18 HTTP
5833 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5834 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5836 Specific command-line options are:
5839 @item --archive=@var{repo}
5840 @itemx -a @var{repo}
5841 @var{repo} identifies the archive repository from which to retrieve the
5842 information. Currently the supported repositories and their identifiers
5846 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5847 identifier. This is the default.
5849 Packages from @code{elpa.gnu.org} are signed with one of the keys
5850 contained in the GnuPG keyring at
5851 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5852 @code{emacs} package (@pxref{Package Installation, ELPA package
5853 signatures,, emacs, The GNU Emacs Manual}).
5856 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5857 @code{melpa-stable} identifier.
5860 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5867 Import metadata from the crates.io Rust package repository
5868 @uref{https://crates.io, crates.io}.
5871 The structure of the @command{guix import} code is modular. It would be
5872 useful to have more importers for other package formats, and your help
5873 is welcome here (@pxref{Contributing}).
5875 @node Invoking guix refresh
5876 @section Invoking @command{guix refresh}
5878 @cindex @command {guix refresh}
5879 The primary audience of the @command{guix refresh} command is developers
5880 of the GNU software distribution. By default, it reports any packages
5881 provided by the distribution that are outdated compared to the latest
5882 upstream version, like this:
5886 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5887 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5890 Alternately, one can specify packages to consider, in which case a
5891 warning is emitted for packages that lack an updater:
5894 $ guix refresh coreutils guile guile-ssh
5895 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5896 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5899 @command{guix refresh} browses the upstream repository of each package and determines
5900 the highest version number of the releases therein. The command
5901 knows how to update specific types of packages: GNU packages, ELPA
5902 packages, etc.---see the documentation for @option{--type} below. There
5903 are many packages, though, for which it lacks a method to determine
5904 whether a new upstream release is available. However, the mechanism is
5905 extensible, so feel free to get in touch with us to add a new method!
5907 When passed @code{--update}, it modifies distribution source files to
5908 update the version numbers and source tarball hashes of those package
5909 recipes (@pxref{Defining Packages}). This is achieved by downloading
5910 each package's latest source tarball and its associated OpenPGP
5911 signature, authenticating the downloaded tarball against its signature
5912 using @command{gpg}, and finally computing its hash. When the public
5913 key used to sign the tarball is missing from the user's keyring, an
5914 attempt is made to automatically retrieve it from a public key server;
5915 when this is successful, the key is added to the user's keyring; otherwise,
5916 @command{guix refresh} reports an error.
5918 The following options are supported:
5922 @item --expression=@var{expr}
5923 @itemx -e @var{expr}
5924 Consider the package @var{expr} evaluates to.
5926 This is useful to precisely refer to a package, as in this example:
5929 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5932 This command lists the dependents of the ``final'' libc (essentially all
5937 Update distribution source files (package recipes) in place. This is
5938 usually run from a checkout of the Guix source tree (@pxref{Running
5939 Guix Before It Is Installed}):
5942 $ ./pre-inst-env guix refresh -s non-core -u
5945 @xref{Defining Packages}, for more information on package definitions.
5947 @item --select=[@var{subset}]
5948 @itemx -s @var{subset}
5949 Select all the packages in @var{subset}, one of @code{core} or
5952 The @code{core} subset refers to all the packages at the core of the
5953 distribution---i.e., packages that are used to build ``everything
5954 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5955 changing one of these packages in the distribution entails a rebuild of
5956 all the others. Thus, such updates are an inconvenience to users in
5957 terms of build time or bandwidth used to achieve the upgrade.
5959 The @code{non-core} subset refers to the remaining packages. It is
5960 typically useful in cases where an update of the core packages would be
5963 @item --manifest=@var{file}
5964 @itemx -m @var{file}
5965 Select all the packages from the manifest in @var{file}. This is useful to
5966 check if any packages of the user manifest can be updated.
5968 @item --type=@var{updater}
5969 @itemx -t @var{updater}
5970 Select only packages handled by @var{updater} (may be a comma-separated
5971 list of updaters). Currently, @var{updater} may be one of:
5975 the updater for GNU packages;
5977 the updater for GNOME packages;
5979 the updater for KDE packages;
5981 the updater for X.org packages;
5983 the updater for packages hosted on kernel.org;
5985 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5987 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5989 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5991 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5993 the updater for @uref{https://pypi.python.org, PyPI} packages.
5995 the updater for @uref{https://rubygems.org, RubyGems} packages.
5997 the updater for @uref{https://github.com, GitHub} packages.
5999 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6001 the updater for @uref{https://www.stackage.org, Stackage} packages.
6003 the updater for @uref{https://crates.io, Crates} packages.
6006 For instance, the following command only checks for updates of Emacs
6007 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6010 $ guix refresh --type=elpa,cran
6011 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6012 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6017 In addition, @command{guix refresh} can be passed one or more package
6018 names, as in this example:
6021 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6025 The command above specifically updates the @code{emacs} and
6026 @code{idutils} packages. The @code{--select} option would have no
6027 effect in this case.
6029 When considering whether to upgrade a package, it is sometimes
6030 convenient to know which packages would be affected by the upgrade and
6031 should be checked for compatibility. For this the following option may
6032 be used when passing @command{guix refresh} one or more package names:
6036 @item --list-updaters
6038 List available updaters and exit (see @option{--type} above.)
6040 For each updater, display the fraction of packages it covers; at the
6041 end, display the fraction of packages covered by all these updaters.
6043 @item --list-dependent
6045 List top-level dependent packages that would need to be rebuilt as a
6046 result of upgrading one or more packages.
6048 @xref{Invoking guix graph, the @code{reverse-package} type of
6049 @command{guix graph}}, for information on how to visualize the list of
6050 dependents of a package.
6054 Be aware that the @code{--list-dependent} option only
6055 @emph{approximates} the rebuilds that would be required as a result of
6056 an upgrade. More rebuilds might be required under some circumstances.
6059 $ guix refresh --list-dependent flex
6060 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6061 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6064 The command above lists a set of packages that could be built to check
6065 for compatibility with an upgraded @code{flex} package.
6067 The following options can be used to customize GnuPG operation:
6071 @item --gpg=@var{command}
6072 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6073 for in @code{$PATH}.
6075 @item --key-download=@var{policy}
6076 Handle missing OpenPGP keys according to @var{policy}, which may be one
6081 Always download missing OpenPGP keys from the key server, and add them
6082 to the user's GnuPG keyring.
6085 Never try to download missing OpenPGP keys. Instead just bail out.
6088 When a package signed with an unknown OpenPGP key is encountered, ask
6089 the user whether to download it or not. This is the default behavior.
6092 @item --key-server=@var{host}
6093 Use @var{host} as the OpenPGP key server when importing a public key.
6097 The @code{github} updater uses the
6098 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6099 releases. When used repeatedly e.g. when refreshing all packages,
6100 GitHub will eventually refuse to answer any further API requests. By
6101 default 60 API requests per hour are allowed, and a full refresh on all
6102 GitHub packages in Guix requires more than this. Authentication with
6103 GitHub through the use of an API token alleviates these limits. To use
6104 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6105 token procured from @uref{https://github.com/settings/tokens} or
6109 @node Invoking guix lint
6110 @section Invoking @command{guix lint}
6112 @cindex @command{guix lint}
6113 @cindex package, checking for errors
6114 The @command{guix lint} command is meant to help package developers avoid
6115 common errors and use a consistent style. It runs a number of checks on
6116 a given set of packages in order to find common mistakes in their
6117 definitions. Available @dfn{checkers} include (see
6118 @code{--list-checkers} for a complete list):
6123 Validate certain typographical and stylistic rules about package
6124 descriptions and synopses.
6126 @item inputs-should-be-native
6127 Identify inputs that should most likely be native inputs.
6132 @itemx source-file-name
6133 Probe @code{home-page} and @code{source} URLs and report those that are
6134 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6135 the source file name is meaningful, e.g. is not
6136 just a version number or ``git-checkout'', without a declared
6137 @code{file-name} (@pxref{origin Reference}).
6140 @cindex security vulnerabilities
6141 @cindex CVE, Common Vulnerabilities and Exposures
6142 Report known vulnerabilities found in the Common Vulnerabilities and
6143 Exposures (CVE) databases of the current and past year
6144 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6147 To view information about a particular vulnerability, visit pages such as:
6151 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6153 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6157 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6158 @code{CVE-2015-7554}.
6160 Package developers can specify in package recipes the
6161 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6162 name and version of the package when they differ from the name that Guix
6163 uses, as in this example:
6169 ;; CPE calls this package "grub2".
6170 (properties '((cpe-name . "grub2"))))
6174 Warn about obvious source code formatting issues: trailing white space,
6175 use of tabulations, etc.
6178 The general syntax is:
6181 guix lint @var{options} @var{package}@dots{}
6184 If no package is given on the command line, then all packages are checked.
6185 The @var{options} may be zero or more of the following:
6188 @item --list-checkers
6190 List and describe all the available checkers that will be run on packages
6195 Only enable the checkers specified in a comma-separated list using the
6196 names returned by @code{--list-checkers}.
6200 @node Invoking guix size
6201 @section Invoking @command{guix size}
6204 @cindex package size
6206 @cindex @command{guix size}
6207 The @command{guix size} command helps package developers profile the
6208 disk usage of packages. It is easy to overlook the impact of an
6209 additional dependency added to a package, or the impact of using a
6210 single output for a package that could easily be split (@pxref{Packages
6211 with Multiple Outputs}). Such are the typical issues that
6212 @command{guix size} can highlight.
6214 The command can be passed a package specification such as @code{gcc@@4.8}
6215 or @code{guile:debug}, or a file name in the store. Consider this
6219 $ guix size coreutils
6220 store item total self
6221 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6222 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6223 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6224 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6225 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6226 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6230 The store items listed here constitute the @dfn{transitive closure} of
6231 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6232 would be returned by:
6235 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6238 Here the output shows three columns next to store items. The first column,
6239 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6240 the store item---that is, its own size plus the size of all its
6241 dependencies. The next column, labeled ``self'', shows the size of the
6242 item itself. The last column shows the ratio of the size of the item
6243 itself to the space occupied by all the items listed here.
6245 In this example, we see that the closure of Coreutils weighs in at
6246 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6247 large fraction of the closure is not a problem @i{per se} because it is
6248 always available on the system anyway.)
6250 When the package passed to @command{guix size} is available in the
6251 store, @command{guix size} queries the daemon to determine its
6252 dependencies, and measures its size in the store, similar to @command{du
6253 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6256 When the given package is @emph{not} in the store, @command{guix size}
6257 reports information based on the available substitutes
6258 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6259 store items that are not even on disk, only available remotely.
6261 You can also specify several package names:
6264 $ guix size coreutils grep sed bash
6265 store item total self
6266 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6267 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6268 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6269 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6275 In this example we see that the combination of the four packages takes
6276 102.3@tie{}MiB in total, which is much less than the sum of each closure
6277 since they have a lot of dependencies in common.
6279 The available options are:
6283 @item --substitute-urls=@var{urls}
6284 Use substitute information from @var{urls}.
6285 @xref{client-substitute-urls, the same option for @code{guix build}}.
6287 @item --map-file=@var{file}
6288 Write a graphical map of disk usage in PNG format to @var{file}.
6290 For the example above, the map looks like this:
6292 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6293 produced by @command{guix size}}
6295 This option requires that
6296 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6297 installed and visible in Guile's module search path. When that is not
6298 the case, @command{guix size} fails as it tries to load it.
6300 @item --system=@var{system}
6301 @itemx -s @var{system}
6302 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6306 @node Invoking guix graph
6307 @section Invoking @command{guix graph}
6310 @cindex @command{guix graph}
6311 @cindex package dependencies
6312 Packages and their dependencies form a @dfn{graph}, specifically a
6313 directed acyclic graph (DAG). It can quickly become difficult to have a
6314 mental model of the package DAG, so the @command{guix graph} command
6315 provides a visual representation of the DAG. By default,
6316 @command{guix graph} emits a DAG representation in the input format of
6317 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6318 directly to the @command{dot} command of Graphviz. It can also emit an
6319 HTML page with embedded JavaScript code to display a ``chord diagram''
6320 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6321 emit Cypher queries to construct a graph in a graph database supporting
6322 the @uref{http://www.opencypher.org/, openCypher} query language.
6323 The general syntax is:
6326 guix graph @var{options} @var{package}@dots{}
6329 For example, the following command generates a PDF file representing the
6330 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6334 guix graph coreutils | dot -Tpdf > dag.pdf
6337 The output looks like this:
6339 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6341 Nice little graph, no?
6343 But there is more than one graph! The one above is concise: it is the
6344 graph of package objects, omitting implicit inputs such as GCC, libc,
6345 grep, etc. It is often useful to have such a concise graph, but
6346 sometimes one may want to see more details. @command{guix graph} supports
6347 several types of graphs, allowing you to choose the level of detail:
6351 This is the default type used in the example above. It shows the DAG of
6352 package objects, excluding implicit dependencies. It is concise, but
6353 filters out many details.
6355 @item reverse-package
6356 This shows the @emph{reverse} DAG of packages. For example:
6359 guix graph --type=reverse-package ocaml
6362 ... yields the graph of packages that depend on OCaml.
6364 Note that for core packages this can yield huge graphs. If all you want
6365 is to know the number of packages that depend on a given package, use
6366 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6367 @option{--list-dependent}}).
6370 This is the package DAG, @emph{including} implicit inputs.
6372 For instance, the following command:
6375 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6378 ... yields this bigger graph:
6380 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6382 At the bottom of the graph, we see all the implicit inputs of
6383 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6385 Now, note that the dependencies of these implicit inputs---that is, the
6386 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6387 here, for conciseness.
6390 Similar to @code{bag-emerged}, but this time including all the bootstrap
6393 @item bag-with-origins
6394 Similar to @code{bag}, but also showing origins and their dependencies.
6397 This is the most detailed representation: It shows the DAG of
6398 derivations (@pxref{Derivations}) and plain store items. Compared to
6399 the above representation, many additional nodes are visible, including
6400 build scripts, patches, Guile modules, etc.
6402 For this type of graph, it is also possible to pass a @file{.drv} file
6403 name instead of a package name, as in:
6406 guix graph -t derivation `guix system build -d my-config.scm`
6410 All the types above correspond to @emph{build-time dependencies}. The
6411 following graph type represents the @emph{run-time dependencies}:
6415 This is the graph of @dfn{references} of a package output, as returned
6416 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6418 If the given package output is not available in the store, @command{guix
6419 graph} attempts to obtain dependency information from substitutes.
6421 Here you can also pass a store file name instead of a package name. For
6422 example, the command below produces the reference graph of your profile
6423 (which can be big!):
6426 guix graph -t references `readlink -f ~/.guix-profile`
6430 This is the graph of the @dfn{referrers} of a store item, as returned by
6431 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6433 This relies exclusively on local information from your store. For
6434 instance, let us suppose that the current Inkscape is available in 10
6435 profiles on your machine; @command{guix graph -t referrers inkscape}
6436 will show a graph rooted at Inkscape and with those 10 profiles linked
6439 It can help determine what is preventing a store item from being garbage
6444 The available options are the following:
6447 @item --type=@var{type}
6448 @itemx -t @var{type}
6449 Produce a graph output of @var{type}, where @var{type} must be one of
6450 the values listed above.
6453 List the supported graph types.
6455 @item --backend=@var{backend}
6456 @itemx -b @var{backend}
6457 Produce a graph using the selected @var{backend}.
6459 @item --list-backends
6460 List the supported graph backends.
6462 Currently, the available backends are Graphviz and d3.js.
6464 @item --expression=@var{expr}
6465 @itemx -e @var{expr}
6466 Consider the package @var{expr} evaluates to.
6468 This is useful to precisely refer to a package, as in this example:
6471 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6476 @node Invoking guix environment
6477 @section Invoking @command{guix environment}
6479 @cindex reproducible build environments
6480 @cindex development environments
6481 @cindex @command{guix environment}
6482 @cindex environment, package build environment
6483 The purpose of @command{guix environment} is to assist hackers in
6484 creating reproducible development environments without polluting their
6485 package profile. The @command{guix environment} tool takes one or more
6486 packages, builds all of their inputs, and creates a shell
6487 environment to use them.
6489 The general syntax is:
6492 guix environment @var{options} @var{package}@dots{}
6495 The following example spawns a new shell set up for the development of
6499 guix environment guile
6502 If the needed dependencies are not built yet, @command{guix environment}
6503 automatically builds them. The environment of the new shell is an augmented
6504 version of the environment that @command{guix environment} was run in.
6505 It contains the necessary search paths for building the given package
6506 added to the existing environment variables. To create a ``pure''
6507 environment, in which the original environment variables have been unset,
6508 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6509 environment variables such as @code{PATH} in their @file{~/.bashrc}
6510 file. As a consequence, when @code{guix environment} launches it, Bash
6511 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6512 environment variables. It is an error to define such environment
6513 variables in @file{.bashrc}; instead, they should be defined in
6514 @file{.bash_profile}, which is sourced only by log-in shells.
6515 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6516 details on Bash start-up files.}.
6518 @vindex GUIX_ENVIRONMENT
6519 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6520 variable in the shell it spawns; its value is the file name of the
6521 profile of this environment. This allows users to, say, define a
6522 specific prompt for development environments in their @file{.bashrc}
6523 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6526 if [ -n "$GUIX_ENVIRONMENT" ]
6528 export PS1="\u@@\h \w [dev]\$ "
6533 ... or to browse the profile:
6536 $ ls "$GUIX_ENVIRONMENT/bin"
6539 Additionally, more than one package may be specified, in which case the
6540 union of the inputs for the given packages are used. For example, the
6541 command below spawns a shell where all of the dependencies of both Guile
6542 and Emacs are available:
6545 guix environment guile emacs
6548 Sometimes an interactive shell session is not desired. An arbitrary
6549 command may be invoked by placing the @code{--} token to separate the
6550 command from the rest of the arguments:
6553 guix environment guile -- make -j4
6556 In other situations, it is more convenient to specify the list of
6557 packages needed in the environment. For example, the following command
6558 runs @command{python} from an environment containing Python@tie{}2.7 and
6562 guix environment --ad-hoc python2-numpy python-2.7 -- python
6565 Furthermore, one might want the dependencies of a package and also some
6566 additional packages that are not build-time or runtime dependencies, but
6567 are useful when developing nonetheless. Because of this, the
6568 @code{--ad-hoc} flag is positional. Packages appearing before
6569 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6570 added to the environment. Packages appearing after are interpreted as
6571 packages that will be added to the environment directly. For example,
6572 the following command creates a Guix development environment that
6573 additionally includes Git and strace:
6576 guix environment guix --ad-hoc git strace
6579 Sometimes it is desirable to isolate the environment as much as
6580 possible, for maximal purity and reproducibility. In particular, when
6581 using Guix on a host distro that is not GuixSD, it is desirable to
6582 prevent access to @file{/usr/bin} and other system-wide resources from
6583 the development environment. For example, the following command spawns
6584 a Guile REPL in a ``container'' where only the store and the current
6585 working directory are mounted:
6588 guix environment --ad-hoc --container guile -- guile
6592 The @code{--container} option requires Linux-libre 3.19 or newer.
6595 The available options are summarized below.
6598 @item --root=@var{file}
6599 @itemx -r @var{file}
6600 @cindex persistent environment
6601 @cindex garbage collector root, for environments
6602 Make @var{file} a symlink to the profile for this environment, and
6603 register it as a garbage collector root.
6605 This is useful if you want to protect your environment from garbage
6606 collection, to make it ``persistent''.
6608 When this option is omitted, the environment is protected from garbage
6609 collection only for the duration of the @command{guix environment}
6610 session. This means that next time you recreate the same environment,
6611 you could have to rebuild or re-download packages.
6613 @item --expression=@var{expr}
6614 @itemx -e @var{expr}
6615 Create an environment for the package or list of packages that
6616 @var{expr} evaluates to.
6618 For example, running:
6621 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6624 starts a shell with the environment for this specific variant of the
6630 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6633 starts a shell with all the GuixSD base packages available.
6635 The above commands only use the default output of the given packages.
6636 To select other outputs, two element tuples can be specified:
6639 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6642 @item --load=@var{file}
6643 @itemx -l @var{file}
6644 Create an environment for the package or list of packages that the code
6645 within @var{file} evaluates to.
6647 As an example, @var{file} might contain a definition like this
6648 (@pxref{Defining Packages}):
6651 @verbatiminclude environment-gdb.scm
6655 Include all specified packages in the resulting environment, as if an
6656 @i{ad hoc} package were defined with them as inputs. This option is
6657 useful for quickly creating an environment without having to write a
6658 package expression to contain the desired inputs.
6660 For instance, the command:
6663 guix environment --ad-hoc guile guile-sdl -- guile
6666 runs @command{guile} in an environment where Guile and Guile-SDL are
6669 Note that this example implicitly asks for the default output of
6670 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6671 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6672 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6674 This option may be composed with the default behavior of @command{guix
6675 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6676 as packages whose dependencies will be added to the environment, the
6677 default behavior. Packages appearing after are interpreted as packages
6678 that will be added to the environment directly.
6681 Unset existing environment variables when building the new environment.
6682 This has the effect of creating an environment in which search paths
6683 only contain package inputs.
6685 @item --search-paths
6686 Display the environment variable definitions that make up the
6689 @item --system=@var{system}
6690 @itemx -s @var{system}
6691 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6696 Run @var{command} within an isolated container. The current working
6697 directory outside the container is mapped inside the container.
6698 Additionally, a dummy home directory is created that matches the current
6699 user's home directory, and @file{/etc/passwd} is configured accordingly.
6700 The spawned process runs as the current user outside the container, but
6701 has root privileges in the context of the container.
6705 For containers, share the network namespace with the host system.
6706 Containers created without this flag only have access to the loopback
6709 @item --expose=@var{source}[=@var{target}]
6710 For containers, expose the file system @var{source} from the host system
6711 as the read-only file system @var{target} within the container. If
6712 @var{target} is not specified, @var{source} is used as the target mount
6713 point in the container.
6715 The example below spawns a Guile REPL in a container in which the user's
6716 home directory is accessible read-only via the @file{/exchange}
6720 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6723 @item --share=@var{source}[=@var{target}]
6724 For containers, share the file system @var{source} from the host system
6725 as the writable file system @var{target} within the container. If
6726 @var{target} is not specified, @var{source} is used as the target mount
6727 point in the container.
6729 The example below spawns a Guile REPL in a container in which the user's
6730 home directory is accessible for both reading and writing via the
6731 @file{/exchange} directory:
6734 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6738 @command{guix environment}
6739 also supports all of the common build options that @command{guix
6740 build} supports (@pxref{Common Build Options}).
6743 @node Invoking guix publish
6744 @section Invoking @command{guix publish}
6746 @cindex @command{guix publish}
6747 The purpose of @command{guix publish} is to enable users to easily share
6748 their store with others, who can then use it as a substitute server
6749 (@pxref{Substitutes}).
6751 When @command{guix publish} runs, it spawns an HTTP server which allows
6752 anyone with network access to obtain substitutes from it. This means
6753 that any machine running Guix can also act as if it were a build farm,
6754 since the HTTP interface is compatible with Hydra, the software behind
6755 the @code{hydra.gnu.org} build farm.
6757 For security, each substitute is signed, allowing recipients to check
6758 their authenticity and integrity (@pxref{Substitutes}). Because
6759 @command{guix publish} uses the signing key of the system, which is only
6760 readable by the system administrator, it must be started as root; the
6761 @code{--user} option makes it drop root privileges early on.
6763 The signing key pair must be generated before @command{guix publish} is
6764 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6767 The general syntax is:
6770 guix publish @var{options}@dots{}
6773 Running @command{guix publish} without any additional arguments will
6774 spawn an HTTP server on port 8080:
6780 Once a publishing server has been authorized (@pxref{Invoking guix
6781 archive}), the daemon may download substitutes from it:
6784 guix-daemon --substitute-urls=http://example.org:8080
6787 By default, @command{guix publish} compresses archives on the fly as it
6788 serves them. This ``on-the-fly'' mode is convenient in that it requires
6789 no setup and is immediately available. However, when serving lots of
6790 clients, we recommend using the @option{--cache} option, which enables
6791 caching of the archives before they are sent to clients---see below for
6794 As a bonus, @command{guix publish} also serves as a content-addressed
6795 mirror for source files referenced in @code{origin} records
6796 (@pxref{origin Reference}). For instance, assuming @command{guix
6797 publish} is running on @code{example.org}, the following URL returns the
6798 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6799 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6802 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6805 Obviously, these URLs only work for files that are in the store; in
6806 other cases, they return 404 (``Not Found'').
6808 The following options are available:
6811 @item --port=@var{port}
6812 @itemx -p @var{port}
6813 Listen for HTTP requests on @var{port}.
6815 @item --listen=@var{host}
6816 Listen on the network interface for @var{host}. The default is to
6817 accept connections from any interface.
6819 @item --user=@var{user}
6820 @itemx -u @var{user}
6821 Change privileges to @var{user} as soon as possible---i.e., once the
6822 server socket is open and the signing key has been read.
6824 @item --compression[=@var{level}]
6825 @itemx -C [@var{level}]
6826 Compress data using the given @var{level}. When @var{level} is zero,
6827 disable compression. The range 1 to 9 corresponds to different gzip
6828 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6831 Unless @option{--cache} is used, compression occurs on the fly and
6832 the compressed streams are not
6833 cached. Thus, to reduce load on the machine that runs @command{guix
6834 publish}, it may be a good idea to choose a low compression level, to
6835 run @command{guix publish} behind a caching proxy, or to use
6836 @option{--cache}. Using @option{--cache} has the advantage that it
6837 allows @command{guix publish} to add @code{Content-Length} HTTP header
6840 @item --cache=@var{directory}
6841 @itemx -c @var{directory}
6842 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6843 and only serve archives that are in cache.
6845 When this option is omitted, archives and meta-data are created
6846 on-the-fly. This can reduce the available bandwidth, especially when
6847 compression is enabled, since this may become CPU-bound. Another
6848 drawback of the default mode is that the length of archives is not known
6849 in advance, so @command{guix publish} does not add a
6850 @code{Content-Length} HTTP header to its responses, which in turn
6851 prevents clients from knowing the amount of data being downloaded.
6853 Conversely, when @option{--cache} is used, the first request for a store
6854 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6855 background process to @dfn{bake} the archive---computing its
6856 @code{.narinfo} and compressing the archive, if needed. Once the
6857 archive is cached in @var{directory}, subsequent requests succeed and
6858 are served directly from the cache, which guarantees that clients get
6859 the best possible bandwidth.
6861 The ``baking'' process is performed by worker threads. By default, one
6862 thread per CPU core is created, but this can be customized. See
6863 @option{--workers} below.
6865 When @option{--ttl} is used, cached entries are automatically deleted
6866 when they have expired.
6868 @item --workers=@var{N}
6869 When @option{--cache} is used, request the allocation of @var{N} worker
6870 threads to ``bake'' archives.
6872 @item --ttl=@var{ttl}
6873 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6874 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6875 days, @code{1m} means 1 month, and so on.
6877 This allows the user's Guix to keep substitute information in cache for
6878 @var{ttl}. However, note that @code{guix publish} does not itself
6879 guarantee that the store items it provides will indeed remain available
6880 for as long as @var{ttl}.
6882 Additionally, when @option{--cache} is used, cached entries that have
6883 not been accessed for @var{ttl} may be deleted.
6885 @item --nar-path=@var{path}
6886 Use @var{path} as the prefix for the URLs of ``nar'' files
6887 (@pxref{Invoking guix archive, normalized archives}).
6889 By default, nars are served at a URL such as
6890 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6891 change the @code{/nar} part to @var{path}.
6893 @item --public-key=@var{file}
6894 @itemx --private-key=@var{file}
6895 Use the specific @var{file}s as the public/private key pair used to sign
6896 the store items being published.
6898 The files must correspond to the same key pair (the private key is used
6899 for signing and the public key is merely advertised in the signature
6900 metadata). They must contain keys in the canonical s-expression format
6901 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6902 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6903 @file{/etc/guix/signing-key.sec} are used.
6905 @item --repl[=@var{port}]
6906 @itemx -r [@var{port}]
6907 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6908 Reference Manual}) on @var{port} (37146 by default). This is used
6909 primarily for debugging a running @command{guix publish} server.
6912 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6913 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6914 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6915 @code{guix-publish-service-type}}).
6917 If you are instead running Guix on a ``foreign distro'', follow these
6922 If your host distro uses the systemd init system:
6925 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6926 /etc/systemd/system/
6927 # systemctl start guix-publish && systemctl enable guix-publish
6931 If your host distro uses the Upstart init system:
6934 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6935 # start guix-publish
6939 Otherwise, proceed similarly with your distro's init system.
6942 @node Invoking guix challenge
6943 @section Invoking @command{guix challenge}
6945 @cindex reproducible builds
6946 @cindex verifiable builds
6947 @cindex @command{guix challenge}
6949 Do the binaries provided by this server really correspond to the source
6950 code it claims to build? Is a package build process deterministic?
6951 These are the questions the @command{guix challenge} command attempts to
6954 The former is obviously an important question: Before using a substitute
6955 server (@pxref{Substitutes}), one had better @emph{verify} that it
6956 provides the right binaries, and thus @emph{challenge} it. The latter
6957 is what enables the former: If package builds are deterministic, then
6958 independent builds of the package should yield the exact same result,
6959 bit for bit; if a server provides a binary different from the one
6960 obtained locally, it may be either corrupt or malicious.
6962 We know that the hash that shows up in @file{/gnu/store} file names is
6963 the hash of all the inputs of the process that built the file or
6964 directory---compilers, libraries, build scripts,
6965 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6966 one store file name should map to exactly one build output.
6967 @command{guix challenge} checks whether there is, indeed, a single
6968 mapping by comparing the build outputs of several independent builds of
6969 any given store item.
6971 The command output looks like this:
6974 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6975 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6976 updating list of substitutes from 'https://guix.example.org'... 100.0%
6977 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6978 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6979 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6980 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6981 /gnu/store/@dots{}-git-2.5.0 contents differ:
6982 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6983 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6984 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6985 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6986 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6987 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6988 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6992 In this example, @command{guix challenge} first scans the store to
6993 determine the set of locally-built derivations---as opposed to store
6994 items that were downloaded from a substitute server---and then queries
6995 all the substitute servers. It then reports those store items for which
6996 the servers obtained a result different from the local build.
6998 @cindex non-determinism, in package builds
6999 As an example, @code{guix.example.org} always gets a different answer.
7000 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7001 case of Git. This might indicate that the build process of Git is
7002 non-deterministic, meaning that its output varies as a function of
7003 various things that Guix does not fully control, in spite of building
7004 packages in isolated environments (@pxref{Features}). Most common
7005 sources of non-determinism include the addition of timestamps in build
7006 results, the inclusion of random numbers, and directory listings sorted
7007 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7010 To find out what is wrong with this Git binary, we can do something along
7011 these lines (@pxref{Invoking guix archive}):
7014 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7015 | guix archive -x /tmp/git
7016 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7019 This command shows the difference between the files resulting from the
7020 local build, and the files resulting from the build on
7021 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7022 diffutils, Comparing and Merging Files}). The @command{diff} command
7023 works great for text files. When binary files differ, a better option
7024 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7025 visualize differences for all kinds of files.
7027 Once you have done that work, you can tell whether the differences are due
7028 to a non-deterministic build process or to a malicious server. We try
7029 hard to remove sources of non-determinism in packages to make it easier
7030 to verify substitutes, but of course, this is a process that
7031 involves not just Guix, but a large part of the free software community.
7032 In the meantime, @command{guix challenge} is one tool to help address
7035 If you are writing packages for Guix, you are encouraged to check
7036 whether @code{hydra.gnu.org} and other substitute servers obtain the
7037 same build result as you did with:
7040 $ guix challenge @var{package}
7044 where @var{package} is a package specification such as
7045 @code{guile@@2.0} or @code{glibc:debug}.
7047 The general syntax is:
7050 guix challenge @var{options} [@var{packages}@dots{}]
7053 When a difference is found between the hash of a locally-built item and
7054 that of a server-provided substitute, or among substitutes provided by
7055 different servers, the command displays it as in the example above and
7056 its exit code is 2 (other non-zero exit codes denote other kinds of
7059 The one option that matters is:
7063 @item --substitute-urls=@var{urls}
7064 Consider @var{urls} the whitespace-separated list of substitute source
7069 Show details about matches (identical contents) in addition to
7070 information about mismatches.
7074 @node Invoking guix copy
7075 @section Invoking @command{guix copy}
7077 @cindex copy, of store items, over SSH
7078 @cindex SSH, copy of store items
7079 @cindex sharing store items across machines
7080 @cindex transferring store items across machines
7081 The @command{guix copy} command copies items from the store of one
7082 machine to that of another machine over a secure shell (SSH)
7083 connection@footnote{This command is available only when Guile-SSH was
7084 found. @xref{Requirements}, for details.}. For example, the following
7085 command copies the @code{coreutils} package, the user's profile, and all
7086 their dependencies over to @var{host}, logged in as @var{user}:
7089 guix copy --to=@var{user}@@@var{host} \
7090 coreutils `readlink -f ~/.guix-profile`
7093 If some of the items to be copied are already present on @var{host},
7094 they are not actually sent.
7096 The command below retrieves @code{libreoffice} and @code{gimp} from
7097 @var{host}, assuming they are available there:
7100 guix copy --from=@var{host} libreoffice gimp
7103 The SSH connection is established using the Guile-SSH client, which is
7104 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7105 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7107 The key used to sign items that are sent must be accepted by the remote
7108 machine. Likewise, the key used by the remote machine to sign items you
7109 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7110 own daemon. @xref{Invoking guix archive}, for more information about
7111 store item authentication.
7113 The general syntax is:
7116 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7119 You must always specify one of the following options:
7122 @item --to=@var{spec}
7123 @itemx --from=@var{spec}
7124 Specify the host to send to or receive from. @var{spec} must be an SSH
7125 spec such as @code{example.org}, @code{charlie@@example.org}, or
7126 @code{charlie@@example.org:2222}.
7129 The @var{items} can be either package names, such as @code{gimp}, or
7130 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7132 When specifying the name of a package to send, it is first built if
7133 needed, unless @option{--dry-run} was specified. Common build options
7134 are supported (@pxref{Common Build Options}).
7137 @node Invoking guix container
7138 @section Invoking @command{guix container}
7140 @cindex @command{guix container}
7142 As of version @value{VERSION}, this tool is experimental. The interface
7143 is subject to radical change in the future.
7146 The purpose of @command{guix container} is to manipulate processes
7147 running within an isolated environment, commonly known as a
7148 ``container'', typically created by the @command{guix environment}
7149 (@pxref{Invoking guix environment}) and @command{guix system container}
7150 (@pxref{Invoking guix system}) commands.
7152 The general syntax is:
7155 guix container @var{action} @var{options}@dots{}
7158 @var{action} specifies the operation to perform with a container, and
7159 @var{options} specifies the context-specific arguments for the action.
7161 The following actions are available:
7165 Execute a command within the context of a running container.
7170 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7173 @var{pid} specifies the process ID of the running container.
7174 @var{program} specifies an executable file name within the root file
7175 system of the container. @var{arguments} are the additional options that
7176 will be passed to @var{program}.
7178 The following command launches an interactive login shell inside a
7179 GuixSD container, started by @command{guix system container}, and whose
7183 guix container exec 9001 /run/current-system/profile/bin/bash --login
7186 Note that the @var{pid} cannot be the parent process of a container. It
7187 must be PID 1 of the container or one of its child processes.
7191 @c *********************************************************************
7192 @node GNU Distribution
7193 @chapter GNU Distribution
7195 @cindex Guix System Distribution
7197 Guix comes with a distribution of the GNU system consisting entirely of
7198 free software@footnote{The term ``free'' here refers to the
7199 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7200 users of that software}.}. The
7201 distribution can be installed on its own (@pxref{System Installation}),
7202 but it is also possible to install Guix as a package manager on top of
7203 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7204 between the two, we refer to the standalone distribution as the Guix
7205 System Distribution, or GuixSD.
7207 The distribution provides core GNU packages such as GNU libc, GCC, and
7208 Binutils, as well as many GNU and non-GNU applications. The complete
7209 list of available packages can be browsed
7210 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7211 running @command{guix package} (@pxref{Invoking guix package}):
7214 guix package --list-available
7217 Our goal is to provide a practical 100% free software distribution of
7218 Linux-based and other variants of GNU, with a focus on the promotion and
7219 tight integration of GNU components, and an emphasis on programs and
7220 tools that help users exert that freedom.
7222 Packages are currently available on the following platforms:
7227 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7230 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7233 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7234 using the EABI hard-float application binary interface (ABI),
7235 and Linux-Libre kernel.
7238 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7239 currently in an experimental stage, with limited support.
7240 @xref{Contributing}, for how to help!
7242 @item mips64el-linux
7243 little-endian 64-bit MIPS processors, specifically the Loongson series,
7244 n32 ABI, and Linux-Libre kernel.
7248 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7251 For information on porting to other architectures or kernels,
7255 * System Installation:: Installing the whole operating system.
7256 * System Configuration:: Configuring the operating system.
7257 * Documentation:: Browsing software user manuals.
7258 * Installing Debugging Files:: Feeding the debugger.
7259 * Security Updates:: Deploying security fixes quickly.
7260 * Package Modules:: Packages from the programmer's viewpoint.
7261 * Packaging Guidelines:: Growing the distribution.
7262 * Bootstrapping:: GNU/Linux built from scratch.
7263 * Porting:: Targeting another platform or kernel.
7266 Building this distribution is a cooperative effort, and you are invited
7267 to join! @xref{Contributing}, for information about how you can help.
7269 @node System Installation
7270 @section System Installation
7272 @cindex installing GuixSD
7273 @cindex Guix System Distribution
7274 This section explains how to install the Guix System Distribution (GuixSD)
7275 on a machine. The Guix package manager can
7276 also be installed on top of a running GNU/Linux system,
7277 @pxref{Installation}.
7281 @c This paragraph is for people reading this from tty2 of the
7282 @c installation image.
7283 You are reading this documentation with an Info reader. For details on
7284 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7285 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7286 Info}. Hit @kbd{l} afterwards to come back here.
7288 Alternately, run @command{info info} in another tty to keep the manual
7294 * Limitations:: What you can expect.
7295 * Hardware Considerations:: Supported hardware.
7296 * USB Stick Installation:: Preparing the installation medium.
7297 * Preparing for Installation:: Networking, partitioning, etc.
7298 * Proceeding with the Installation:: The real thing.
7299 * Installing GuixSD in a VM:: GuixSD playground.
7300 * Building the Installation Image:: How this comes to be.
7304 @subsection Limitations
7306 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7307 not production-ready. It may contain bugs and lack important
7308 features. Thus, if you are looking for a stable production system that
7309 respects your freedom as a computer user, a good solution at this point
7310 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7311 the more established GNU/Linux distributions}. We hope you can soon switch
7312 to the GuixSD without fear, of course. In the meantime, you can
7313 also keep using your distribution and try out the package manager on top
7314 of it (@pxref{Installation}).
7316 Before you proceed with the installation, be aware of the following
7317 noteworthy limitations applicable to version @value{VERSION}:
7321 The installation process does not include a graphical user interface and
7322 requires familiarity with GNU/Linux (see the following subsections to
7323 get a feel of what that means.)
7326 Support for the Logical Volume Manager (LVM) is missing.
7329 More and more system services are provided (@pxref{Services}), but some
7333 More than 5,300 packages are available, but you may
7334 occasionally find that a useful package is missing.
7337 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7338 as well as a number of X11 window managers. However, some graphical
7339 applications may be missing, as well as KDE.
7342 You have been warned! But more than a disclaimer, this is an invitation
7343 to report issues (and success stories!), and to join us in improving it.
7344 @xref{Contributing}, for more info.
7347 @node Hardware Considerations
7348 @subsection Hardware Considerations
7350 @cindex hardware support on GuixSD
7351 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7352 builds around the kernel Linux-libre, which means that only hardware for
7353 which free software drivers and firmware exist is supported. Nowadays,
7354 a wide range of off-the-shelf hardware is supported on
7355 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7356 Ethernet controllers. Unfortunately, there are still areas where
7357 hardware vendors deny users control over their own computing, and such
7358 hardware is not supported on GuixSD.
7360 @cindex WiFi, hardware support
7361 One of the main areas where free drivers or firmware are lacking is WiFi
7362 devices. WiFi devices known to work include those using Atheros chips
7363 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7364 driver, and those using Broadcom/AirForce chips (BCM43xx with
7365 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7366 Linux-libre driver. Free firmware exists for both and is available
7367 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7368 (@pxref{operating-system Reference, @code{firmware}}).
7370 @cindex RYF, Respects Your Freedom
7371 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7372 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7373 certification program for hardware products that respect your freedom
7374 and your privacy and ensure that you have control over your device. We
7375 encourage you to check the list of RYF-certified devices.
7377 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7378 web site. It contains a catalog of hardware devices with information
7379 about their support in GNU/Linux.
7382 @node USB Stick Installation
7383 @subsection USB Stick Installation
7385 An installation image for USB sticks can be downloaded from
7386 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7387 where @var{system} is one of:
7391 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7394 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7397 @c start duplication of authentication part from ``Binary Installation''
7398 Make sure to download the associated @file{.sig} file and to verify the
7399 authenticity of the image against it, along these lines:
7402 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7403 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7406 If that command fails because you do not have the required public key,
7407 then run this command to import it:
7410 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7414 and rerun the @code{gpg --verify} command.
7417 This image contains a single partition with the tools necessary for an
7418 installation. It is meant to be copied @emph{as is} to a large-enough
7421 To copy the image to a USB stick, follow these steps:
7425 Decompress the image using the @command{xz} command:
7428 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7432 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7433 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7434 copy the image with:
7437 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7441 Access to @file{/dev/sdX} usually requires root privileges.
7444 Once this is done, you should be able to reboot the system and boot from
7445 the USB stick. The latter usually requires you to get in the BIOS or
7446 UEFI boot menu, where you can choose to boot from the USB stick.
7448 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7449 GuixSD in a virtual machine (VM).
7451 @node Preparing for Installation
7452 @subsection Preparing for Installation
7454 Once you have successfully booted the image on the USB stick, you should
7455 end up with a root prompt. Several console TTYs are configured and can
7456 be used to run commands as root. TTY2 shows this documentation,
7457 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7458 Stand-alone GNU Info}). The installation system runs the GPM mouse
7459 daemon, which allows you to select text with the left mouse button and
7460 to paste it with the middle button.
7463 Installation requires access to the Internet so that any missing
7464 dependencies of your system configuration can be downloaded. See the
7465 ``Networking'' section below.
7468 The installation system includes many common tools needed for this task.
7469 But it is also a full-blown GuixSD system, which means that you can
7470 install additional packages, should you need it, using @command{guix
7471 package} (@pxref{Invoking guix package}).
7473 @subsubsection Keyboard Layout
7475 @cindex keyboard layout
7476 The installation image uses the US qwerty keyboard layout. If you want
7477 to change it, you can use the @command{loadkeys} command. For example,
7478 the following command selects the Dvorak keyboard layout:
7484 See the files under @file{/run/current-system/profile/share/keymaps} for
7485 a list of available keyboard layouts. Run @command{man loadkeys} for
7488 @subsubsection Networking
7490 Run the following command see what your network interfaces are called:
7497 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7503 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7504 Wired interfaces have a name starting with @samp{e}; for example, the
7505 interface corresponding to the first on-board Ethernet controller is
7506 called @samp{eno1}. Wireless interfaces have a name starting with
7507 @samp{w}, like @samp{w1p2s0}.
7510 @item Wired connection
7511 To configure a wired network run the following command, substituting
7512 @var{interface} with the name of the wired interface you want to use.
7515 ifconfig @var{interface} up
7518 @item Wireless connection
7521 To configure wireless networking, you can create a configuration file
7522 for the @command{wpa_supplicant} configuration tool (its location is not
7523 important) using one of the available text editors such as
7527 zile wpa_supplicant.conf
7530 As an example, the following stanza can go to this file and will work
7531 for many wireless networks, provided you give the actual SSID and
7532 passphrase for the network you are connecting to:
7536 ssid="@var{my-ssid}"
7538 psk="the network's secret passphrase"
7542 Start the wireless service and run it in the background with the
7543 following command (substitute @var{interface} with the name of the
7544 network interface you want to use):
7547 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7550 Run @command{man wpa_supplicant} for more information.
7554 At this point, you need to acquire an IP address. On a network where IP
7555 addresses are automatically assigned @i{via} DHCP, you can run:
7558 dhclient -v @var{interface}
7561 Try to ping a server to see if networking is up and running:
7567 Setting up network access is almost always a requirement because the
7568 image does not contain all the software and tools that may be needed.
7570 @cindex installing over SSH
7571 If you want to, you can continue the installation remotely by starting
7575 herd start ssh-daemon
7578 Make sure to either set a password with @command{passwd}, or configure
7579 OpenSSH public key authentication before logging in.
7581 @subsubsection Disk Partitioning
7583 Unless this has already been done, the next step is to partition, and
7584 then format the target partition(s).
7586 The installation image includes several partitioning tools, including
7587 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7588 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7589 the partition layout you want:
7595 If your disk uses the GUID Partition Table (GPT) format and you plan to
7596 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7597 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7600 @cindex EFI, installation
7601 @cindex UEFI, installation
7602 @cindex ESP, EFI system partition
7603 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7604 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7605 must have the @code{esp} flag set. E.g., for @command{parted}:
7608 parted /dev/sda set 1 esp on
7611 Once you are done partitioning the target hard disk drive, you have to
7612 create a file system on the relevant partition(s)@footnote{Currently
7613 GuixSD only supports ext4 and btrfs file systems. In particular, code
7614 that reads partition UUIDs and labels only works for these file system
7617 Preferably, assign partitions a label so that you can easily and
7618 reliably refer to them in @code{file-system} declarations (@pxref{File
7619 Systems}). This is typically done using the @code{-L} option of
7620 @command{mkfs.ext4} and related commands. So, assuming the target root
7621 partition lives at @file{/dev/sda1}, a file system with the label
7622 @code{my-root} can be created with:
7625 mkfs.ext4 -L my-root /dev/sda1
7628 @cindex encrypted disk
7629 If you are instead planning to encrypt the root partition, you can use
7630 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7631 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7632 @code{man cryptsetup}} for more information.) Assuming you want to
7633 store the root partition on @file{/dev/sda1}, the command sequence would
7634 be along these lines:
7637 cryptsetup luksFormat /dev/sda1
7638 cryptsetup open --type luks /dev/sda1 my-partition
7639 mkfs.ext4 -L my-root /dev/mapper/my-partition
7642 Once that is done, mount the target root partition under @file{/mnt}
7643 with a command like (again, assuming @code{my-root} is the label of the
7647 mount LABEL=my-root /mnt
7650 Also mount any other partitions you would like to use on the target
7651 system relative to this path. If you have @file{/boot} on a separate
7652 partition for example, mount it at @file{/mnt/boot} now so it is found
7653 by @code{guix system init} afterwards.
7655 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7656 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7657 sure to initialize them with @command{mkswap}. Assuming you have one
7658 swap partition on @file{/dev/sda2}, you would run:
7665 Alternatively, you may use a swap file. For example, assuming that in
7666 the new system you want to use the file @file{/swapfile} as a swap file,
7667 you would run@footnote{This example will work for many types of file
7668 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7669 btrfs), the required steps may be different. For details, see the
7670 manual pages for @command{mkswap} and @command{swapon}.}:
7673 # This is 10 GiB of swap space. Adjust "count" to change the size.
7674 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7675 # For security, make the file readable and writable only by root.
7676 chmod 600 /mnt/swapfile
7677 mkswap /mnt/swapfile
7678 swapon /mnt/swapfile
7681 Note that if you have encrypted the root partition and created a swap
7682 file in its file system as described above, then the encryption also
7683 protects the swap file, just like any other file in that file system.
7685 @node Proceeding with the Installation
7686 @subsection Proceeding with the Installation
7688 With the target partitions ready and the target root mounted on
7689 @file{/mnt}, we're ready to go. First, run:
7692 herd start cow-store /mnt
7695 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7696 during the installation phase are written to the target disk on @file{/mnt}
7697 rather than kept in memory. This is necessary because the first phase of
7698 the @command{guix system init} command (see below) entails downloads or
7699 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7701 Next, you have to edit a file and
7702 provide the declaration of the operating system to be installed. To
7703 that end, the installation system comes with three text editors: GNU nano
7704 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7705 nvi (a clone of the original BSD @command{vi} editor).
7706 We strongly recommend storing that file on the target root file system, say,
7707 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7708 configuration file once you have rebooted into the newly-installed system.
7710 @xref{Using the Configuration System}, for an overview of the
7711 configuration file. The example configurations discussed in that
7712 section are available under @file{/etc/configuration} in the
7713 installation image. Thus, to get started with a system configuration
7714 providing a graphical display server (a ``desktop'' system), you can run
7715 something along these lines:
7719 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7720 # zile /mnt/etc/config.scm
7723 You should pay attention to what your configuration file contains, and
7728 Make sure the @code{grub-configuration} form refers to the device you
7729 want to install GRUB on. You also need to specify the @code{grub-efi}
7730 package if you wish to use native UEFI boot.
7733 Be sure that your partition labels match the value of their respective
7734 @code{device} fields in your @code{file-system} configuration, assuming
7735 your @code{file-system} configuration sets the value of @code{title} to
7739 If there are encrypted or RAID partitions, make sure to add a
7740 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7743 Once you are done preparing the configuration file, the new system must
7744 be initialized (remember that the target root file system is mounted
7748 guix system init /mnt/etc/config.scm /mnt
7752 This copies all the necessary files and installs GRUB on
7753 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7754 more information, @pxref{Invoking guix system}. This command may trigger
7755 downloads or builds of missing packages, which can take some time.
7757 Once that command has completed---and hopefully succeeded!---you can run
7758 @command{reboot} and boot into the new system. The @code{root} password
7759 in the new system is initially empty; other users' passwords need to be
7760 initialized by running the @command{passwd} command as @code{root},
7761 unless your configuration specifies otherwise
7762 (@pxref{user-account-password, user account passwords}).
7764 @cindex upgrading GuixSD
7765 From then on, you can update GuixSD whenever you want by running
7766 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7767 then running @command{guix system reconfigure} to build a new system
7768 generation with the latest packages and services (@pxref{Invoking guix
7769 system}). We recommend doing that regularly so that your system
7770 includes the latest security updates (@pxref{Security Updates}).
7772 Join us on @code{#guix} on the Freenode IRC network or on
7773 @file{guix-devel@@gnu.org} to share your experience---good or not so
7776 @node Installing GuixSD in a VM
7777 @subsection Installing GuixSD in a Virtual Machine
7779 @cindex virtual machine, GuixSD installation
7780 @cindex virtual private server (VPS)
7781 @cindex VPS (virtual private server)
7782 If you'd like to install GuixSD in a virtual machine (VM) or on a
7783 virtual private server (VPS) rather than on your beloved machine, this
7786 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7787 disk image, follow these steps:
7791 First, retrieve and decompress the GuixSD installation image as
7792 described previously (@pxref{USB Stick Installation}).
7795 Create a disk image that will hold the installed system. To make a
7796 qcow2-formatted disk image, use the @command{qemu-img} command:
7799 qemu-img create -f qcow2 guixsd.img 50G
7802 The resulting file will be much smaller than 50 GB (typically less than
7803 1 MB), but it will grow as the virtualized storage device is filled up.
7806 Boot the USB installation image in an VM:
7809 qemu-system-x86_64 -m 1024 -smp 1 \
7810 -net user -net nic,model=virtio -boot menu=on \
7811 -drive file=guixsd-usb-install-@value{VERSION}.@var{system} \
7812 -drive file=guixsd.img
7815 The ordering of the drives matters.
7817 In the VM console, quickly press the @kbd{F12} key to enter the boot
7818 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7822 You're now root in the VM, proceed with the installation process.
7823 @xref{Preparing for Installation}, and follow the instructions.
7826 Once installation is complete, you can boot the system that's on your
7827 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7830 @node Building the Installation Image
7831 @subsection Building the Installation Image
7833 @cindex installation image
7834 The installation image described above was built using the @command{guix
7835 system} command, specifically:
7837 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7839 guix system disk-image --image-size=1G gnu/system/install.scm
7842 Have a look at @file{gnu/system/install.scm} in the source tree,
7843 and see also @ref{Invoking guix system} for more information
7844 about the installation image.
7846 @node System Configuration
7847 @section System Configuration
7849 @cindex system configuration
7850 The Guix System Distribution supports a consistent whole-system configuration
7851 mechanism. By that we mean that all aspects of the global system
7852 configuration---such as the available system services, timezone and
7853 locale settings, user accounts---are declared in a single place. Such
7854 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7856 One of the advantages of putting all the system configuration under the
7857 control of Guix is that it supports transactional system upgrades, and
7858 makes it possible to roll back to a previous system instantiation,
7859 should something go wrong with the new one (@pxref{Features}). Another
7860 advantage is that it makes it easy to replicate the exact same configuration
7861 across different machines, or at different points in time, without
7862 having to resort to additional administration tools layered on top of
7863 the own tools of the system.
7864 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7866 This section describes this mechanism. First we focus on the system
7867 administrator's viewpoint---explaining how the system is configured and
7868 instantiated. Then we show how this mechanism can be extended, for
7869 instance to support new system services.
7872 * Using the Configuration System:: Customizing your GNU system.
7873 * operating-system Reference:: Detail of operating-system declarations.
7874 * File Systems:: Configuring file system mounts.
7875 * Mapped Devices:: Block device extra processing.
7876 * User Accounts:: Specifying user accounts.
7877 * Locales:: Language and cultural convention settings.
7878 * Services:: Specifying system services.
7879 * Setuid Programs:: Programs running with root privileges.
7880 * X.509 Certificates:: Authenticating HTTPS servers.
7881 * Name Service Switch:: Configuring libc's name service switch.
7882 * Initial RAM Disk:: Linux-Libre bootstrapping.
7883 * Bootloader Configuration:: Configuring the boot loader.
7884 * Invoking guix system:: Instantiating a system configuration.
7885 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7886 * Defining Services:: Adding new service definitions.
7889 @node Using the Configuration System
7890 @subsection Using the Configuration System
7892 The operating system is configured by providing an
7893 @code{operating-system} declaration in a file that can then be passed to
7894 the @command{guix system} command (@pxref{Invoking guix system}). A
7895 simple setup, with the default system services, the default Linux-Libre
7896 kernel, initial RAM disk, and boot loader looks like this:
7898 @findex operating-system
7900 @include os-config-bare-bones.texi
7903 This example should be self-describing. Some of the fields defined
7904 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7905 Others, such as @code{packages} and @code{services}, can be omitted, in
7906 which case they get a default value.
7908 Below we discuss the effect of some of the most important fields
7909 (@pxref{operating-system Reference}, for details about all the available
7910 fields), and how to @dfn{instantiate} the operating system using
7911 @command{guix system}.
7913 @unnumberedsubsubsec Globally-Visible Packages
7915 @vindex %base-packages
7916 The @code{packages} field lists packages that will be globally visible
7917 on the system, for all user accounts---i.e., in every user's @code{PATH}
7918 environment variable---in addition to the per-user profiles
7919 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7920 provides all the tools one would expect for basic user and administrator
7921 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7922 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7923 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7924 packages admin)} module (@pxref{Package Modules}). The
7925 @code{(list package output)} syntax can be used to add a specific output
7929 (use-modules (gnu packages))
7930 (use-modules (gnu packages dns))
7934 (packages (cons (list bind "utils")
7938 @findex specification->package
7939 Referring to packages by variable name, like @var{tcpdump} above, has
7940 the advantage of being unambiguous; it also allows typos and such to be
7941 diagnosed right away as ``unbound variables''. The downside is that one
7942 needs to know which module defines which package, and to augment the
7943 @code{use-package-modules} line accordingly. To avoid that, one can use
7944 the @code{specification->package} procedure of the @code{(gnu packages)}
7945 module, which returns the best package for a given name or name and
7949 (use-modules (gnu packages))
7953 (packages (append (map specification->package
7954 '("tcpdump" "htop" "gnupg@@2.0"))
7958 @unnumberedsubsubsec System Services
7961 @vindex %base-services
7962 The @code{services} field lists @dfn{system services} to be made
7963 available when the system starts (@pxref{Services}).
7964 The @code{operating-system} declaration above specifies that, in
7965 addition to the basic services, we want the @command{lshd} secure shell
7966 daemon listening on port 2222 (@pxref{Networking Services,
7967 @code{lsh-service}}). Under the hood,
7968 @code{lsh-service} arranges so that @code{lshd} is started with the
7969 right command-line options, possibly with supporting configuration files
7970 generated as needed (@pxref{Defining Services}).
7972 @cindex customization, of services
7973 @findex modify-services
7974 Occasionally, instead of using the base services as is, you will want to
7975 customize them. To do this, use @code{modify-services} (@pxref{Service
7976 Reference, @code{modify-services}}) to modify the list.
7978 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7979 (the console log-in) in the @var{%base-services} list (@pxref{Base
7980 Services, @code{%base-services}}). To do that, you can write the
7981 following in your operating system declaration:
7984 (define %my-services
7985 ;; My very own list of services.
7986 (modify-services %base-services
7987 (guix-service-type config =>
7990 (use-substitutes? #f)
7991 (extra-options '("--gc-keep-derivations"))))
7992 (mingetty-service-type config =>
7993 (mingetty-configuration
7994 (inherit config)))))
7998 (services %my-services))
8001 This changes the configuration---i.e., the service parameters---of the
8002 @code{guix-service-type} instance, and that of all the
8003 @code{mingetty-service-type} instances in the @var{%base-services} list.
8004 Observe how this is accomplished: first, we arrange for the original
8005 configuration to be bound to the identifier @code{config} in the
8006 @var{body}, and then we write the @var{body} so that it evaluates to the
8007 desired configuration. In particular, notice how we use @code{inherit}
8008 to create a new configuration which has the same values as the old
8009 configuration, but with a few modifications.
8011 @cindex encrypted disk
8012 The configuration for a typical ``desktop'' usage, with an encrypted
8013 root partition, the X11 display
8014 server, GNOME and Xfce (users can choose which of these desktop
8015 environments to use at the log-in screen by pressing @kbd{F1}), network
8016 management, power management, and more, would look like this:
8019 @include os-config-desktop.texi
8022 A graphical UEFI system with a choice of lightweight window managers
8023 instead of full-blown desktop environments would look like this:
8026 @include os-config-lightweight-desktop.texi
8029 @xref{Desktop Services}, for the exact list of services provided by
8030 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8031 information about the @code{nss-certs} package that is used here.
8033 Again, @var{%desktop-services} is just a list of service objects. If
8034 you want to remove services from there, you can do so using the
8035 procedures for list filtering (@pxref{SRFI-1 Filtering and
8036 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8037 following expression returns a list that contains all the services in
8038 @var{%desktop-services} minus the Avahi service:
8041 (remove (lambda (service)
8042 (eq? (service-kind service) avahi-service-type))
8046 @unnumberedsubsubsec Instantiating the System
8048 Assuming the @code{operating-system} declaration
8049 is stored in the @file{my-system-config.scm}
8050 file, the @command{guix system reconfigure my-system-config.scm} command
8051 instantiates that configuration, and makes it the default GRUB boot
8052 entry (@pxref{Invoking guix system}).
8054 The normal way to change the system configuration is by updating this
8055 file and re-running @command{guix system reconfigure}. One should never
8056 have to touch files in @file{/etc} or to run commands that modify the
8057 system state such as @command{useradd} or @command{grub-install}. In
8058 fact, you must avoid that since that would not only void your warranty
8059 but also prevent you from rolling back to previous versions of your
8060 system, should you ever need to.
8062 @cindex roll-back, of the operating system
8063 Speaking of roll-back, each time you run @command{guix system
8064 reconfigure}, a new @dfn{generation} of the system is created---without
8065 modifying or deleting previous generations. Old system generations get
8066 an entry in the bootloader boot menu, allowing you to boot them in case
8067 something went wrong with the latest generation. Reassuring, no? The
8068 @command{guix system list-generations} command lists the system
8069 generations available on disk. It is also possible to roll back the
8070 system via the commands @command{guix system roll-back} and
8071 @command{guix system switch-generation}.
8073 Although the command @command{guix system reconfigure} will not modify
8074 previous generations, must take care when the current generation is not
8075 the latest (e.g., after invoking @command{guix system roll-back}), since
8076 the operation might overwrite a later generation (@pxref{Invoking guix
8079 @unnumberedsubsubsec The Programming Interface
8081 At the Scheme level, the bulk of an @code{operating-system} declaration
8082 is instantiated with the following monadic procedure (@pxref{The Store
8085 @deffn {Monadic Procedure} operating-system-derivation os
8086 Return a derivation that builds @var{os}, an @code{operating-system}
8087 object (@pxref{Derivations}).
8089 The output of the derivation is a single directory that refers to all
8090 the packages, configuration files, and other supporting files needed to
8091 instantiate @var{os}.
8094 This procedure is provided by the @code{(gnu system)} module. Along
8095 with @code{(gnu services)} (@pxref{Services}), this module contains the
8096 guts of GuixSD. Make sure to visit it!
8099 @node operating-system Reference
8100 @subsection @code{operating-system} Reference
8102 This section summarizes all the options available in
8103 @code{operating-system} declarations (@pxref{Using the Configuration
8106 @deftp {Data Type} operating-system
8107 This is the data type representing an operating system configuration.
8108 By that, we mean all the global system configuration, not per-user
8109 configuration (@pxref{Using the Configuration System}).
8112 @item @code{kernel} (default: @var{linux-libre})
8113 The package object of the operating system kernel to use@footnote{Currently
8114 only the Linux-libre kernel is supported. In the future, it will be
8115 possible to use the GNU@tie{}Hurd.}.
8117 @item @code{kernel-arguments} (default: @code{'()})
8118 List of strings or gexps representing additional arguments to pass on
8119 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8121 @item @code{bootloader}
8122 The system bootloader configuration object. @xref{Bootloader Configuration}.
8124 @item @code{initrd} (default: @code{base-initrd})
8126 @cindex initial RAM disk
8127 A two-argument monadic procedure that returns an initial RAM disk for
8128 the Linux kernel. @xref{Initial RAM Disk}.
8130 @item @code{firmware} (default: @var{%base-firmware})
8132 List of firmware packages loadable by the operating system kernel.
8134 The default includes firmware needed for Atheros- and Broadcom-based
8135 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8136 respectively). @xref{Hardware Considerations}, for more info on
8139 @item @code{host-name}
8142 @item @code{hosts-file}
8144 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8145 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8146 Reference Manual}). The default is a file with entries for
8147 @code{localhost} and @var{host-name}.
8149 @item @code{mapped-devices} (default: @code{'()})
8150 A list of mapped devices. @xref{Mapped Devices}.
8152 @item @code{file-systems}
8153 A list of file systems. @xref{File Systems}.
8155 @item @code{swap-devices} (default: @code{'()})
8156 @cindex swap devices
8157 A list of strings identifying devices or files to be used for ``swap
8158 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8159 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8160 It is possible to specify a swap file in a file system on a mapped
8161 device, provided that the necessary device mapping and file system are
8162 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8164 @item @code{users} (default: @code{%base-user-accounts})
8165 @itemx @code{groups} (default: @var{%base-groups})
8166 List of user accounts and groups. @xref{User Accounts}.
8168 @item @code{skeletons} (default: @code{(default-skeletons)})
8169 A list target file name/file-like object tuples (@pxref{G-Expressions,
8170 file-like objects}). These are the skeleton files that will be added to
8171 the home directory of newly-created user accounts.
8173 For instance, a valid value may look like this:
8176 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8177 (".guile" ,(plain-file "guile"
8178 "(use-modules (ice-9 readline))
8179 (activate-readline)")))
8182 @item @code{issue} (default: @var{%default-issue})
8183 A string denoting the contents of the @file{/etc/issue} file, which is
8184 displayed when users log in on a text console.
8186 @item @code{packages} (default: @var{%base-packages})
8187 The set of packages installed in the global profile, which is accessible
8188 at @file{/run/current-system/profile}.
8190 The default set includes core utilities and it is good practice to
8191 install non-core utilities in user profiles (@pxref{Invoking guix
8194 @item @code{timezone}
8195 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8197 You can run the @command{tzselect} command to find out which timezone
8198 string corresponds to your region. Choosing an invalid timezone name
8199 causes @command{guix system} to fail.
8201 @item @code{locale} (default: @code{"en_US.utf8"})
8202 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8203 Library Reference Manual}). @xref{Locales}, for more information.
8205 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8206 The list of locale definitions to be compiled and that may be used at
8207 run time. @xref{Locales}.
8209 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8210 The list of GNU@tie{}libc packages whose locale data and tools are used
8211 to build the locale definitions. @xref{Locales}, for compatibility
8212 considerations that justify this option.
8214 @item @code{name-service-switch} (default: @var{%default-nss})
8215 Configuration of the libc name service switch (NSS)---a
8216 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8219 @item @code{services} (default: @var{%base-services})
8220 A list of service objects denoting system services. @xref{Services}.
8222 @item @code{pam-services} (default: @code{(base-pam-services)})
8224 @cindex pluggable authentication modules
8225 Linux @dfn{pluggable authentication module} (PAM) services.
8226 @c FIXME: Add xref to PAM services section.
8228 @item @code{setuid-programs} (default: @var{%setuid-programs})
8229 List of string-valued G-expressions denoting setuid programs.
8230 @xref{Setuid Programs}.
8232 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8233 @cindex sudoers file
8234 The contents of the @file{/etc/sudoers} file as a file-like object
8235 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8237 This file specifies which users can use the @command{sudo} command, what
8238 they are allowed to do, and what privileges they may gain. The default
8239 is that only @code{root} and members of the @code{wheel} group may use
8246 @subsection File Systems
8248 The list of file systems to be mounted is specified in the
8249 @code{file-systems} field of the operating system declaration
8250 (@pxref{Using the Configuration System}). Each file system is declared
8251 using the @code{file-system} form, like this:
8255 (mount-point "/home")
8256 (device "/dev/sda3")
8260 As usual, some of the fields are mandatory---those shown in the example
8261 above---while others can be omitted. These are described below.
8263 @deftp {Data Type} file-system
8264 Objects of this type represent file systems to be mounted. They
8265 contain the following members:
8269 This is a string specifying the type of the file system---e.g.,
8272 @item @code{mount-point}
8273 This designates the place where the file system is to be mounted.
8276 This names the ``source'' of the file system. By default it is the name
8277 of a node under @file{/dev}, but its meaning depends on the @code{title}
8278 field described below.
8280 @item @code{title} (default: @code{'device})
8281 This is a symbol that specifies how the @code{device} field is to be
8284 When it is the symbol @code{device}, then the @code{device} field is
8285 interpreted as a file name; when it is @code{label}, then @code{device}
8286 is interpreted as a partition label name; when it is @code{uuid},
8287 @code{device} is interpreted as a partition unique identifier (UUID).
8289 UUIDs may be converted from their string representation (as shown by the
8290 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8291 @code{uuid} form expects 16-byte UUIDs as defined in
8292 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8293 form of UUID used by the ext2 family of file systems and others, but it
8294 is different from ``UUIDs'' found in FAT file systems, for instance.},
8299 (mount-point "/home")
8302 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8305 The @code{label} and @code{uuid} options offer a way to refer to disk
8306 partitions without having to hard-code their actual device
8307 name@footnote{Note that, while it is tempting to use
8308 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8309 result, this is not recommended: These special device nodes are created
8310 by the udev daemon and may be unavailable at the time the device is
8313 However, when the source of a file system is a mapped device (@pxref{Mapped
8314 Devices}), its @code{device} field @emph{must} refer to the mapped
8315 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8316 @code{title} must be set to @code{'device}. This is required so that
8317 the system knows that mounting the file system depends on having the
8318 corresponding device mapping established.
8320 @item @code{flags} (default: @code{'()})
8321 This is a list of symbols denoting mount flags. Recognized flags
8322 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8323 access to special files), @code{no-suid} (ignore setuid and setgid
8324 bits), and @code{no-exec} (disallow program execution.)
8326 @item @code{options} (default: @code{#f})
8327 This is either @code{#f}, or a string denoting mount options.
8329 @item @code{mount?} (default: @code{#t})
8330 This value indicates whether to automatically mount the file system when
8331 the system is brought up. When set to @code{#f}, the file system gets
8332 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8333 is not automatically mounted.
8335 @item @code{needed-for-boot?} (default: @code{#f})
8336 This Boolean value indicates whether the file system is needed when
8337 booting. If that is true, then the file system is mounted when the
8338 initial RAM disk (initrd) is loaded. This is always the case, for
8339 instance, for the root file system.
8341 @item @code{check?} (default: @code{#t})
8342 This Boolean indicates whether the file system needs to be checked for
8343 errors before being mounted.
8345 @item @code{create-mount-point?} (default: @code{#f})
8346 When true, the mount point is created if it does not exist yet.
8348 @item @code{dependencies} (default: @code{'()})
8349 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8350 representing file systems that must be mounted or mapped devices that
8351 must be opened before (and unmounted or closed after) this one.
8353 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8354 a dependency of @file{/sys/fs/cgroup/cpu} and
8355 @file{/sys/fs/cgroup/memory}.
8357 Another example is a file system that depends on a mapped device, for
8358 example for an encrypted partition (@pxref{Mapped Devices}).
8362 The @code{(gnu system file-systems)} exports the following useful
8365 @defvr {Scheme Variable} %base-file-systems
8366 These are essential file systems that are required on normal systems,
8367 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8368 below.) Operating system declarations should always contain at least
8372 @defvr {Scheme Variable} %pseudo-terminal-file-system
8373 This is the file system to be mounted as @file{/dev/pts}. It supports
8374 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8375 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8376 Manual}). Pseudo-terminals are used by terminal emulators such as
8380 @defvr {Scheme Variable} %shared-memory-file-system
8381 This file system is mounted as @file{/dev/shm} and is used to support
8382 memory sharing across processes (@pxref{Memory-mapped I/O,
8383 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8386 @defvr {Scheme Variable} %immutable-store
8387 This file system performs a read-only ``bind mount'' of
8388 @file{/gnu/store}, making it read-only for all the users including
8389 @code{root}. This prevents against accidental modification by software
8390 running as @code{root} or by system administrators.
8392 The daemon itself is still able to write to the store: it remounts it
8393 read-write in its own ``name space.''
8396 @defvr {Scheme Variable} %binary-format-file-system
8397 The @code{binfmt_misc} file system, which allows handling of arbitrary
8398 executable file types to be delegated to user space. This requires the
8399 @code{binfmt.ko} kernel module to be loaded.
8402 @defvr {Scheme Variable} %fuse-control-file-system
8403 The @code{fusectl} file system, which allows unprivileged users to mount
8404 and unmount user-space FUSE file systems. This requires the
8405 @code{fuse.ko} kernel module to be loaded.
8408 @node Mapped Devices
8409 @subsection Mapped Devices
8411 @cindex device mapping
8412 @cindex mapped devices
8413 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8414 such as a hard disk partition, can be @dfn{mapped} into another device,
8415 usually in @code{/dev/mapper/},
8416 with additional processing over the data that flows through
8417 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8418 concept of a ``mapped device'' and that of a file system: both boil down
8419 to @emph{translating} input/output operations made on a file to
8420 operations on its backing store. Thus, the Hurd implements mapped
8421 devices, like file systems, using the generic @dfn{translator} mechanism
8422 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8423 typical example is encryption device mapping: all writes to the mapped
8424 device are encrypted, and all reads are deciphered, transparently.
8425 Guix extends this notion by considering any device or set of devices that
8426 are @dfn{transformed} in some way to create a new device; for instance,
8427 RAID devices are obtained by @dfn{assembling} several other devices, such
8428 as hard disks or partitions, into a new one that behaves as one partition.
8429 Other examples, not yet implemented, are LVM logical volumes.
8431 Mapped devices are declared using the @code{mapped-device} form,
8432 defined as follows; for examples, see below.
8434 @deftp {Data Type} mapped-device
8435 Objects of this type represent device mappings that will be made when
8436 the system boots up.
8440 This is either a string specifying the name of the block device to be mapped,
8441 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8442 need to be assembled for creating a new one.
8445 This string specifies the name of the resulting mapped device. For
8446 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8447 specifying @code{"my-partition"} leads to the creation of
8448 the @code{"/dev/mapper/my-partition"} device.
8449 For RAID devices of type @code{raid-device-mapping}, the full device name
8450 such as @code{"/dev/md0"} needs to be given.
8453 This must be a @code{mapped-device-kind} object, which specifies how
8454 @var{source} is mapped to @var{target}.
8458 @defvr {Scheme Variable} luks-device-mapping
8459 This defines LUKS block device encryption using the @command{cryptsetup}
8460 command from the package with the same name. It relies on the
8461 @code{dm-crypt} Linux kernel module.
8464 @defvr {Scheme Variable} raid-device-mapping
8465 This defines a RAID device, which is assembled using the @code{mdadm}
8466 command from the package with the same name. It requires a Linux kernel
8467 module for the appropriate RAID level to be loaded, such as @code{raid456}
8468 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8471 @cindex disk encryption
8473 The following example specifies a mapping from @file{/dev/sda3} to
8474 @file{/dev/mapper/home} using LUKS---the
8475 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8476 standard mechanism for disk encryption.
8477 The @file{/dev/mapper/home}
8478 device can then be used as the @code{device} of a @code{file-system}
8479 declaration (@pxref{File Systems}).
8483 (source "/dev/sda3")
8485 (type luks-device-mapping))
8488 Alternatively, to become independent of device numbering, one may obtain
8489 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8493 cryptsetup luksUUID /dev/sda3
8496 and use it as follows:
8500 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8502 (type luks-device-mapping))
8505 @cindex swap encryption
8506 It is also desirable to encrypt swap space, since swap space may contain
8507 sensitive data. One way to accomplish that is to use a swap file in a
8508 file system on a device mapped via LUKS encryption. In this way, the
8509 swap file is encrypted because the entire device is encrypted.
8510 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8512 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8513 may be declared as follows:
8517 (source (list "/dev/sda1" "/dev/sdb1"))
8519 (type raid-device-mapping))
8522 The @file{/dev/md0} device can then be used as the @code{device} of a
8523 @code{file-system} declaration (@pxref{File Systems}).
8524 Note that the RAID level need not be given; it is chosen during the
8525 initial creation and formatting of the RAID device and is determined
8526 automatically later.
8530 @subsection User Accounts
8534 @cindex user accounts
8535 User accounts and groups are entirely managed through the
8536 @code{operating-system} declaration. They are specified with the
8537 @code{user-account} and @code{user-group} forms:
8543 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8545 "video" ;video devices such as webcams
8546 "cdrom")) ;the good ol' CD-ROM
8547 (comment "Bob's sister")
8548 (home-directory "/home/alice"))
8551 When booting or upon completion of @command{guix system reconfigure},
8552 the system ensures that only the user accounts and groups specified in
8553 the @code{operating-system} declaration exist, and with the specified
8554 properties. Thus, account or group creations or modifications made by
8555 directly invoking commands such as @command{useradd} are lost upon
8556 reconfiguration or reboot. This ensures that the system remains exactly
8559 @deftp {Data Type} user-account
8560 Objects of this type represent user accounts. The following members may
8565 The name of the user account.
8569 This is the name (a string) or identifier (a number) of the user group
8570 this account belongs to.
8572 @item @code{supplementary-groups} (default: @code{'()})
8573 Optionally, this can be defined as a list of group names that this
8576 @item @code{uid} (default: @code{#f})
8577 This is the user ID for this account (a number), or @code{#f}. In the
8578 latter case, a number is automatically chosen by the system when the
8581 @item @code{comment} (default: @code{""})
8582 A comment about the account, such as the account owner's full name.
8584 @item @code{home-directory}
8585 This is the name of the home directory for the account.
8587 @item @code{create-home-directory?} (default: @code{#t})
8588 Indicates whether the home directory of this account should be created
8589 if it does not exist yet.
8591 @item @code{shell} (default: Bash)
8592 This is a G-expression denoting the file name of a program to be used as
8593 the shell (@pxref{G-Expressions}).
8595 @item @code{system?} (default: @code{#f})
8596 This Boolean value indicates whether the account is a ``system''
8597 account. System accounts are sometimes treated specially; for instance,
8598 graphical login managers do not list them.
8600 @anchor{user-account-password}
8601 @item @code{password} (default: @code{#f})
8602 You would normally leave this field to @code{#f}, initialize user
8603 passwords as @code{root} with the @command{passwd} command, and then let
8604 users change it with @command{passwd}. Passwords set with
8605 @command{passwd} are of course preserved across reboot and
8608 If you @emph{do} want to have a preset password for an account, then
8609 this field must contain the encrypted password, as a string.
8610 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8611 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8612 Manual}, for information on Guile's @code{crypt} procedure.
8618 User group declarations are even simpler:
8621 (user-group (name "students"))
8624 @deftp {Data Type} user-group
8625 This type is for, well, user groups. There are just a few fields:
8629 The name of the group.
8631 @item @code{id} (default: @code{#f})
8632 The group identifier (a number). If @code{#f}, a new number is
8633 automatically allocated when the group is created.
8635 @item @code{system?} (default: @code{#f})
8636 This Boolean value indicates whether the group is a ``system'' group.
8637 System groups have low numerical IDs.
8639 @item @code{password} (default: @code{#f})
8640 What, user groups can have a password? Well, apparently yes. Unless
8641 @code{#f}, this field specifies the password of the group.
8646 For convenience, a variable lists all the basic user groups one may
8649 @defvr {Scheme Variable} %base-groups
8650 This is the list of basic user groups that users and/or packages expect
8651 to be present on the system. This includes groups such as ``root'',
8652 ``wheel'', and ``users'', as well as groups used to control access to
8653 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8656 @defvr {Scheme Variable} %base-user-accounts
8657 This is the list of basic system accounts that programs may expect to
8658 find on a GNU/Linux system, such as the ``nobody'' account.
8660 Note that the ``root'' account is not included here. It is a
8661 special-case and is automatically added whether or not it is specified.
8668 A @dfn{locale} defines cultural conventions for a particular language
8669 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8670 Reference Manual}). Each locale has a name that typically has the form
8671 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8672 @code{fr_LU.utf8} designates the locale for the French language, with
8673 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8675 @cindex locale definition
8676 Usually, you will want to specify the default locale for the machine
8677 using the @code{locale} field of the @code{operating-system} declaration
8678 (@pxref{operating-system Reference, @code{locale}}).
8680 The selected locale is automatically added to the @dfn{locale
8681 definitions} known to the system if needed, with its codeset inferred
8682 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8683 @code{UTF-8} codeset. Additional locale definitions can be specified in
8684 the @code{locale-definitions} slot of @code{operating-system}---this is
8685 useful, for instance, if the codeset could not be inferred from the
8686 locale name. The default set of locale definitions includes some widely
8687 used locales, but not all the available locales, in order to save space.
8689 For instance, to add the North Frisian locale for Germany, the value of
8693 (cons (locale-definition
8694 (name "fy_DE.utf8") (source "fy_DE"))
8695 %default-locale-definitions)
8698 Likewise, to save space, one might want @code{locale-definitions} to
8699 list only the locales that are actually used, as in:
8702 (list (locale-definition
8703 (name "ja_JP.eucjp") (source "ja_JP")
8704 (charset "EUC-JP")))
8708 The compiled locale definitions are available at
8709 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8710 version, which is the default location where the GNU@tie{}libc provided
8711 by Guix looks for locale data. This can be overridden using the
8712 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8713 @code{LOCPATH} and locale packages}).
8715 The @code{locale-definition} form is provided by the @code{(gnu system
8716 locale)} module. Details are given below.
8718 @deftp {Data Type} locale-definition
8719 This is the data type of a locale definition.
8724 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8725 Reference Manual}, for more information on locale names.
8728 The name of the source for that locale. This is typically the
8729 @code{@var{language}_@var{territory}} part of the locale name.
8731 @item @code{charset} (default: @code{"UTF-8"})
8732 The ``character set'' or ``code set'' for that locale,
8733 @uref{http://www.iana.org/assignments/character-sets, as defined by
8739 @defvr {Scheme Variable} %default-locale-definitions
8740 A list of commonly used UTF-8 locales, used as the default
8741 value of the @code{locale-definitions} field of @code{operating-system}
8745 @cindex normalized codeset in locale names
8746 These locale definitions use the @dfn{normalized codeset} for the part
8747 that follows the dot in the name (@pxref{Using gettextized software,
8748 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8749 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8753 @subsubsection Locale Data Compatibility Considerations
8755 @cindex incompatibility, of locale data
8756 @code{operating-system} declarations provide a @code{locale-libcs} field
8757 to specify the GNU@tie{}libc packages that are used to compile locale
8758 declarations (@pxref{operating-system Reference}). ``Why would I
8759 care?'', you may ask. Well, it turns out that the binary format of
8760 locale data is occasionally incompatible from one libc version to
8763 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8764 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8765 For instance, a program linked against libc version 2.21 is unable to
8766 read locale data produced with libc 2.22; worse, that program
8767 @emph{aborts} instead of simply ignoring the incompatible locale
8768 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8769 the incompatible locale data, which is already an improvement.}.
8770 Similarly, a program linked against libc 2.22 can read most, but not
8771 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8772 data is incompatible); thus calls to @code{setlocale} may fail, but
8773 programs will not abort.
8775 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8776 choose whether and when to upgrade software in their profiles, and might
8777 be using a libc version different from the one the system administrator
8778 used to build the system-wide locale data.
8780 Fortunately, unprivileged users can also install their own locale data
8781 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8782 @code{GUIX_LOCPATH} and locale packages}).
8784 Still, it is best if the system-wide locale data at
8785 @file{/run/current-system/locale} is built for all the libc versions
8786 actually in use on the system, so that all the programs can access
8787 it---this is especially crucial on a multi-user system. To do that, the
8788 administrator can specify several libc packages in the
8789 @code{locale-libcs} field of @code{operating-system}:
8792 (use-package-modules base)
8796 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8799 This example would lead to a system containing locale definitions for
8800 both libc 2.21 and the current version of libc in
8801 @file{/run/current-system/locale}.
8805 @subsection Services
8807 @cindex system services
8808 An important part of preparing an @code{operating-system} declaration is
8809 listing @dfn{system services} and their configuration (@pxref{Using the
8810 Configuration System}). System services are typically daemons launched
8811 when the system boots, or other actions needed at that time---e.g.,
8812 configuring network access.
8814 GuixSD has a broad definition of ``service'' (@pxref{Service
8815 Composition}), but many services are managed by the GNU@tie{}Shepherd
8816 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8817 command allows you to list the available services, show their status,
8818 start and stop them, or do other specific operations (@pxref{Jump
8819 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8825 The above command, run as @code{root}, lists the currently defined
8826 services. The @command{herd doc} command shows a synopsis of the given
8831 Run libc's name service cache daemon (nscd).
8834 The @command{start}, @command{stop}, and @command{restart} sub-commands
8835 have the effect you would expect. For instance, the commands below stop
8836 the nscd service and restart the Xorg display server:
8840 Service nscd has been stopped.
8841 # herd restart xorg-server
8842 Service xorg-server has been stopped.
8843 Service xorg-server has been started.
8846 The following sections document the available services, starting with
8847 the core services, that may be used in an @code{operating-system}
8851 * Base Services:: Essential system services.
8852 * Scheduled Job Execution:: The mcron service.
8853 * Log Rotation:: The rottlog service.
8854 * Networking Services:: Network setup, SSH daemon, etc.
8855 * X Window:: Graphical display.
8856 * Printing Services:: Local and remote printer support.
8857 * Desktop Services:: D-Bus and desktop services.
8858 * Database Services:: SQL databases.
8859 * Mail Services:: IMAP, POP3, SMTP, and all that.
8860 * Messaging Services:: Messaging services.
8861 * Kerberos Services:: Kerberos services.
8862 * Web Services:: Web servers.
8863 * DNS Services:: DNS daemons.
8864 * VPN Services:: VPN daemons.
8865 * Network File System:: NFS related services.
8866 * Continuous Integration:: The Cuirass service.
8867 * Power management Services:: The TLP tool.
8868 * Miscellaneous Services:: Other services.
8872 @subsubsection Base Services
8874 The @code{(gnu services base)} module provides definitions for the basic
8875 services that one expects from the system. The services exported by
8876 this module are listed below.
8878 @defvr {Scheme Variable} %base-services
8879 This variable contains a list of basic services (@pxref{Service Types
8880 and Services}, for more information on service objects) one would
8881 expect from the system: a login service (mingetty) on each tty, syslogd,
8882 the libc name service cache daemon (nscd), the udev device manager, and
8885 This is the default value of the @code{services} field of
8886 @code{operating-system} declarations. Usually, when customizing a
8887 system, you will want to append services to @var{%base-services}, like
8891 (cons* (avahi-service) (lsh-service) %base-services)
8895 @defvr {Scheme Variable} special-files-service-type
8896 This is the service that sets up ``special files'' such as
8897 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8899 The value associated with @code{special-files-service-type} services
8900 must be a list of tuples where the first element is the ``special file''
8901 and the second element is its target. By default it is:
8903 @cindex @file{/bin/sh}
8904 @cindex @file{sh}, in @file{/bin}
8906 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8909 @cindex @file{/usr/bin/env}
8910 @cindex @file{env}, in @file{/usr/bin}
8911 If you want to add, say, @code{/usr/bin/env} to your system, you can
8915 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8916 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8919 Since this is part of @code{%base-services}, you can use
8920 @code{modify-services} to customize the set of special files
8921 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8922 to add a special file is @i{via} the @code{extra-special-file} procedure
8926 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8927 Use @var{target} as the ``special file'' @var{file}.
8929 For example, adding the following lines to the @code{services} field of
8930 your operating system declaration leads to a @file{/usr/bin/env}
8934 (extra-special-file "/usr/bin/env"
8935 (file-append coreutils "/bin/env"))
8939 @deffn {Scheme Procedure} host-name-service @var{name}
8940 Return a service that sets the host name to @var{name}.
8943 @deffn {Scheme Procedure} login-service @var{config}
8944 Return a service to run login according to @var{config}, a
8945 @code{<login-configuration>} object, which specifies the message of the day,
8949 @deftp {Data Type} login-configuration
8950 This is the data type representing the configuration of login.
8955 @cindex message of the day
8956 A file-like object containing the ``message of the day''.
8958 @item @code{allow-empty-passwords?} (default: @code{#t})
8959 Allow empty passwords by default so that first-time users can log in when
8960 the 'root' account has just been created.
8965 @deffn {Scheme Procedure} mingetty-service @var{config}
8966 Return a service to run mingetty according to @var{config}, a
8967 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8971 @deftp {Data Type} mingetty-configuration
8972 This is the data type representing the configuration of Mingetty, which
8973 provides the default implementation of virtual console log-in.
8978 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8980 @item @code{auto-login} (default: @code{#f})
8981 When true, this field must be a string denoting the user name under
8982 which the system automatically logs in. When it is @code{#f}, a
8983 user name and password must be entered to log in.
8985 @item @code{login-program} (default: @code{#f})
8986 This must be either @code{#f}, in which case the default log-in program
8987 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8988 the name of the log-in program.
8990 @item @code{login-pause?} (default: @code{#f})
8991 When set to @code{#t} in conjunction with @var{auto-login}, the user
8992 will have to press a key before the log-in shell is launched.
8994 @item @code{mingetty} (default: @var{mingetty})
8995 The Mingetty package to use.
9000 @deffn {Scheme Procedure} agetty-service @var{config}
9001 Return a service to run agetty according to @var{config}, an
9002 @code{<agetty-configuration>} object, which specifies the tty to run,
9006 @deftp {Data Type} agetty-configuration
9007 This is the data type representing the configuration of agetty, which
9008 implements virtual and serial console log-in. See the @code{agetty(8)}
9009 man page for more information.
9014 The name of the console this agetty runs on, as a string---e.g.,
9015 @code{"ttyS0"}. This argument is mandatory.
9017 @item @code{baud-rate} (default: @code{#f})
9018 A string containing a comma-separated list of one or more baud rates, in
9021 @item @code{term} (default: @code{#f})
9022 A string containing the value used for the @code{TERM} environment
9025 @item @code{eight-bits?} (default: @code{#f})
9026 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9029 @item @code{auto-login} (default: @code{#f})
9030 When passed a login name, as a string, the specified user will be logged
9031 in automatically without prompting for their login name or password.
9033 @item @code{no-reset?} (default: @code{#f})
9034 When @code{#t}, don't reset terminal cflags (control modes).
9036 @item @code{host} (default: @code{#f})
9037 This accepts a string containing the "login_host", which will be written
9038 into the @file{/var/run/utmpx} file.
9040 @item @code{remote?} (default: @code{#f})
9041 When set to @code{#t} in conjunction with @var{host}, this will add an
9042 @code{-r} fakehost option to the command line of the login program
9043 specified in @var{login-program}.
9045 @item @code{flow-control?} (default: @code{#f})
9046 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9048 @item @code{no-issue?} (default: @code{#f})
9049 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9050 not be displayed before presenting the login prompt.
9052 @item @code{init-string} (default: @code{#f})
9053 This accepts a string that will be sent to the tty or modem before
9054 sending anything else. It can be used to initialize a modem.
9056 @item @code{no-clear?} (default: @code{#f})
9057 When set to @code{#t}, agetty will not clear the screen before showing
9060 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9061 This must be either a gexp denoting the name of a log-in program, or
9062 unset, in which case the default value is the @command{login} from the
9065 @item @code{local-line} (default: @code{#f})
9066 Control the CLOCAL line flag. This accepts one of three symbols as
9067 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9068 the default value chosen by agetty is @code{'auto}.
9070 @item @code{extract-baud?} (default: @code{#f})
9071 When set to @code{#t}, instruct agetty to try to extract the baud rate
9072 from the status messages produced by certain types of modems.
9074 @item @code{skip-login?} (default: @code{#f})
9075 When set to @code{#t}, do not prompt the user for a login name. This
9076 can be used with @var{login-program} field to use non-standard login
9079 @item @code{no-newline?} (default: @code{#f})
9080 When set to @code{#t}, do not print a newline before printing the
9081 @file{/etc/issue} file.
9083 @c Is this dangerous only when used with login-program, or always?
9084 @item @code{login-options} (default: @code{#f})
9085 This option accepts a string containing options that are passed to the
9086 login program. When used with the @var{login-program}, be aware that a
9087 malicious user could try to enter a login name containing embedded
9088 options that could be parsed by the login program.
9090 @item @code{login-pause} (default: @code{#f})
9091 When set to @code{#t}, wait for any key before showing the login prompt.
9092 This can be used in conjunction with @var{auto-login} to save memory by
9093 lazily spawning shells.
9095 @item @code{chroot} (default: @code{#f})
9096 Change root to the specified directory. This option accepts a directory
9099 @item @code{hangup?} (default: @code{#f})
9100 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9103 @item @code{keep-baud?} (default: @code{#f})
9104 When set to @code{#t}, try to keep the existing baud rate. The baud
9105 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9108 @item @code{timeout} (default: @code{#f})
9109 When set to an integer value, terminate if no user name could be read
9110 within @var{timeout} seconds.
9112 @item @code{detect-case?} (default: @code{#f})
9113 When set to @code{#t}, turn on support for detecting an uppercase-only
9114 terminal. This setting will detect a login name containing only
9115 uppercase letters as indicating an uppercase-only terminal and turn on
9116 some upper-to-lower case conversions. Note that this will not support
9119 @item @code{wait-cr?} (default: @code{#f})
9120 When set to @code{#t}, wait for the user or modem to send a
9121 carriage-return or linefeed character before displaying
9122 @file{/etc/issue} or login prompt. This is typically used with the
9123 @var{init-string} option.
9125 @item @code{no-hints?} (default: @code{#f})
9126 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9129 @item @code{no-hostname?} (default: @code{#f})
9130 By default, the hostname is printed. When this option is set to
9131 @code{#t}, no hostname will be shown at all.
9133 @item @code{long-hostname?} (default: @code{#f})
9134 By default, the hostname is only printed until the first dot. When this
9135 option is set to @code{#t}, the fully qualified hostname by
9136 @code{gethostname} or @code{getaddrinfo} is shown.
9138 @item @code{erase-characters} (default: @code{#f})
9139 This option accepts a string of additional characters that should be
9140 interpreted as backspace when the user types their login name.
9142 @item @code{kill-characters} (default: @code{#f})
9143 This option accepts a string that should be interpreted to mean "ignore
9144 all previous characters" (also called a "kill" character) when the types
9147 @item @code{chdir} (default: @code{#f})
9148 This option accepts, as a string, a directory path that will be changed
9151 @item @code{delay} (default: @code{#f})
9152 This options accepts, as an integer, the number of seconds to sleep
9153 before opening the tty and displaying the login prompt.
9155 @item @code{nice} (default: @code{#f})
9156 This option accepts, as an integer, the nice value with which to run the
9157 @command{login} program.
9159 @item @code{extra-options} (default: @code{'()})
9160 This option provides an "escape hatch" for the user to provide arbitrary
9161 command-line arguments to @command{agetty} as a list of strings.
9166 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9167 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9168 according to @var{config}, a @code{<kmscon-configuration>} object, which
9169 specifies the tty to run, among other things.
9172 @deftp {Data Type} kmscon-configuration
9173 This is the data type representing the configuration of Kmscon, which
9174 implements virtual console log-in.
9178 @item @code{virtual-terminal}
9179 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9181 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9182 A gexp denoting the name of the log-in program. The default log-in program is
9183 @command{login} from the Shadow tool suite.
9185 @item @code{login-arguments} (default: @code{'("-p")})
9186 A list of arguments to pass to @command{login}.
9188 @item @code{hardware-acceleration?} (default: #f)
9189 Whether to use hardware acceleration.
9191 @item @code{kmscon} (default: @var{kmscon})
9192 The Kmscon package to use.
9197 @cindex name service cache daemon
9199 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9200 [#:name-services '()]
9201 Return a service that runs the libc name service cache daemon (nscd) with the
9202 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9203 Service Switch}, for an example.
9206 @defvr {Scheme Variable} %nscd-default-configuration
9207 This is the default @code{<nscd-configuration>} value (see below) used
9208 by @code{nscd-service}. It uses the caches defined by
9209 @var{%nscd-default-caches}; see below.
9212 @deftp {Data Type} nscd-configuration
9213 This is the data type representing the name service cache daemon (nscd)
9218 @item @code{name-services} (default: @code{'()})
9219 List of packages denoting @dfn{name services} that must be visible to
9220 the nscd---e.g., @code{(list @var{nss-mdns})}.
9222 @item @code{glibc} (default: @var{glibc})
9223 Package object denoting the GNU C Library providing the @command{nscd}
9226 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9227 Name of the nscd log file. This is where debugging output goes when
9228 @code{debug-level} is strictly positive.
9230 @item @code{debug-level} (default: @code{0})
9231 Integer denoting the debugging levels. Higher numbers mean that more
9232 debugging output is logged.
9234 @item @code{caches} (default: @var{%nscd-default-caches})
9235 List of @code{<nscd-cache>} objects denoting things to be cached; see
9241 @deftp {Data Type} nscd-cache
9242 Data type representing a cache database of nscd and its parameters.
9246 @item @code{database}
9247 This is a symbol representing the name of the database to be cached.
9248 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9249 @code{services}, which designate the corresponding NSS database
9250 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9252 @item @code{positive-time-to-live}
9253 @itemx @code{negative-time-to-live} (default: @code{20})
9254 A number representing the number of seconds during which a positive or
9255 negative lookup result remains in cache.
9257 @item @code{check-files?} (default: @code{#t})
9258 Whether to check for updates of the files corresponding to
9261 For instance, when @var{database} is @code{hosts}, setting this flag
9262 instructs nscd to check for updates in @file{/etc/hosts} and to take
9265 @item @code{persistent?} (default: @code{#t})
9266 Whether the cache should be stored persistently on disk.
9268 @item @code{shared?} (default: @code{#t})
9269 Whether the cache should be shared among users.
9271 @item @code{max-database-size} (default: 32@tie{}MiB)
9272 Maximum size in bytes of the database cache.
9274 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9275 @c settings, so leave them out.
9280 @defvr {Scheme Variable} %nscd-default-caches
9281 List of @code{<nscd-cache>} objects used by default by
9282 @code{nscd-configuration} (see above).
9284 It enables persistent and aggressive caching of service and host name
9285 lookups. The latter provides better host name lookup performance,
9286 resilience in the face of unreliable name servers, and also better
9287 privacy---often the result of host name lookups is in local cache, so
9288 external name servers do not even need to be queried.
9291 @anchor{syslog-configuration-type}
9294 @deftp {Data Type} syslog-configuration
9295 This data type represents the configuration of the syslog daemon.
9298 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9299 The syslog daemon to use.
9301 @item @code{config-file} (default: @code{%default-syslog.conf})
9302 The syslog configuration file to use.
9307 @anchor{syslog-service}
9309 @deffn {Scheme Procedure} syslog-service @var{config}
9310 Return a service that runs a syslog daemon according to @var{config}.
9312 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9313 information on the configuration file syntax.
9316 @anchor{guix-configuration-type}
9317 @deftp {Data Type} guix-configuration
9318 This data type represents the configuration of the Guix build daemon.
9319 @xref{Invoking guix-daemon}, for more information.
9322 @item @code{guix} (default: @var{guix})
9323 The Guix package to use.
9325 @item @code{build-group} (default: @code{"guixbuild"})
9326 Name of the group for build user accounts.
9328 @item @code{build-accounts} (default: @code{10})
9329 Number of build user accounts to create.
9331 @item @code{authorize-key?} (default: @code{#t})
9332 @cindex substitutes, authorization thereof
9333 Whether to authorize the substitute keys listed in
9334 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9335 (@pxref{Substitutes}).
9337 @vindex %default-authorized-guix-keys
9338 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9339 The list of authorized key files for archive imports, as a list of
9340 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9341 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9343 @item @code{use-substitutes?} (default: @code{#t})
9344 Whether to use substitutes.
9346 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9347 The list of URLs where to look for substitutes by default.
9349 @item @code{max-silent-time} (default: @code{0})
9350 @itemx @code{timeout} (default: @code{0})
9351 The number of seconds of silence and the number of seconds of activity,
9352 respectively, after which a build process times out. A value of zero
9353 disables the timeout.
9355 @item @code{extra-options} (default: @code{'()})
9356 List of extra command-line options for @command{guix-daemon}.
9358 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9359 File where @command{guix-daemon}'s standard output and standard error
9362 @item @code{lsof} (default: @var{lsof})
9363 The lsof package to use.
9365 @item @code{http-proxy} (default: @code{#f})
9366 The HTTP proxy used for downloading fixed-output derivations and
9369 @item @code{tmpdir} (default: @code{#f})
9370 A directory path where the @command{guix-daemon} will perform builds.
9375 @deffn {Scheme Procedure} guix-service @var{config}
9376 Return a service that runs the Guix build daemon according to
9380 @deffn {Scheme Procedure} udev-service [#:udev udev]
9381 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9384 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9385 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9389 @defvr {Scheme Variable} %random-seed-file
9390 This is the name of the file where some random bytes are saved by
9391 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9392 It defaults to @file{/var/lib/random-seed}.
9397 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9398 @cindex keyboard layout
9399 Return a service to load console keymaps from @var{files} using
9400 @command{loadkeys} command. Most likely, you want to load some default
9401 keymap, which can be done like this:
9404 (console-keymap-service "dvorak")
9407 Or, for example, for a Swedish keyboard, you may need to combine
9408 the following keymaps:
9410 (console-keymap-service "se-lat6" "se-fi-lat6")
9413 Also you can specify a full file name (or file names) of your keymap(s).
9414 See @code{man loadkeys} for details.
9420 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9422 Run @var{gpm}, the general-purpose mouse daemon, with the given
9423 command-line @var{options}. GPM allows users to use the mouse in the console,
9424 notably to select, copy, and paste text. The default value of @var{options}
9425 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9427 This service is not part of @var{%base-services}.
9430 @anchor{guix-publish-service-type}
9431 @deffn {Scheme Variable} guix-publish-service-type
9432 This is the service type for @command{guix publish} (@pxref{Invoking
9433 guix publish}). Its value must be a @code{guix-configuration}
9434 object, as described below.
9436 This assumes that @file{/etc/guix} already contains a signing key pair as
9437 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9438 archive}). If that is not the case, the service will fail to start.
9441 @deftp {Data Type} guix-publish-configuration
9442 Data type representing the configuration of the @code{guix publish}
9446 @item @code{guix} (default: @code{guix})
9447 The Guix package to use.
9449 @item @code{port} (default: @code{80})
9450 The TCP port to listen for connections.
9452 @item @code{host} (default: @code{"localhost"})
9453 The host (and thus, network interface) to listen to. Use
9454 @code{"0.0.0.0"} to listen on all the network interfaces.
9456 @item @code{compression-level} (default: @code{3})
9457 The gzip compression level at which substitutes are compressed. Use
9458 @code{0} to disable compression altogether, and @code{9} to get the best
9459 compression ratio at the expense of increased CPU usage.
9461 @item @code{nar-path} (default: @code{"nar"})
9462 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9463 publish, @code{--nar-path}}, for details.
9465 @item @code{cache} (default: @code{#f})
9466 When it is @code{#f}, disable caching and instead generate archives on
9467 demand. Otherwise, this should be the name of a directory---e.g.,
9468 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9469 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9470 @option{--cache}}, for more information on the tradeoffs involved.
9472 @item @code{workers} (default: @code{#f})
9473 When it is an integer, this is the number of worker threads used for
9474 caching; when @code{#f}, the number of processors is used.
9475 @xref{Invoking guix publish, @option{--workers}}, for more information.
9477 @item @code{ttl} (default: @code{#f})
9478 When it is an integer, this denotes the @dfn{time-to-live} of the
9479 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9484 @anchor{rngd-service}
9485 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9486 [#:device "/dev/hwrng"]
9487 Return a service that runs the @command{rngd} program from @var{rng-tools}
9488 to add @var{device} to the kernel's entropy pool. The service will fail if
9489 @var{device} does not exist.
9492 @anchor{pam-limits-service}
9493 @cindex session limits
9496 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9498 Return a service that installs a configuration file for the
9499 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9500 @code{pam_limits} module}. The procedure optionally takes a list of
9501 @code{pam-limits-entry} values, which can be used to specify
9502 @code{ulimit} limits and nice priority limits to user sessions.
9504 The following limits definition sets two hard and soft limits for all
9505 login sessions of users in the @code{realtime} group:
9510 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9511 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9514 The first entry increases the maximum realtime priority for
9515 non-privileged processes; the second entry lifts any restriction of the
9516 maximum address space that can be locked in memory. These settings are
9517 commonly used for real-time audio systems.
9520 @node Scheduled Job Execution
9521 @subsubsection Scheduled Job Execution
9525 @cindex scheduling jobs
9526 The @code{(gnu services mcron)} module provides an interface to
9527 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9528 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9529 Unix @command{cron} daemon; the main difference is that it is
9530 implemented in Guile Scheme, which provides a lot of flexibility when
9531 specifying the scheduling of jobs and their actions.
9533 The example below defines an operating system that runs the
9534 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9535 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9536 well as the @command{mkid} command on behalf of an unprivileged user
9537 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9538 gexps to introduce job definitions that are passed to mcron
9539 (@pxref{G-Expressions}).
9542 (use-modules (guix) (gnu) (gnu services mcron))
9543 (use-package-modules base idutils)
9545 (define updatedb-job
9546 ;; Run 'updatedb' at 3AM every day. Here we write the
9547 ;; job's action as a Scheme procedure.
9548 #~(job '(next-hour '(3))
9550 (execl (string-append #$findutils "/bin/updatedb")
9552 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9554 (define garbage-collector-job
9555 ;; Collect garbage 5 minutes after midnight every day.
9556 ;; The job's action is a shell command.
9557 #~(job "5 0 * * *" ;Vixie cron syntax
9561 ;; Update the index database as user "charlie" at 12:15PM
9562 ;; and 19:15PM. This runs from the user's home directory.
9563 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9564 (string-append #$idutils "/bin/mkid src")
9569 (services (cons (mcron-service (list garbage-collector-job
9575 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9576 for more information on mcron job specifications. Below is the
9577 reference of the mcron service.
9579 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9580 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9581 list of gexps denoting mcron job specifications.
9583 This is a shorthand for:
9585 (service mcron-service-type
9586 (mcron-configuration (mcron mcron) (jobs jobs)))
9590 @defvr {Scheme Variable} mcron-service-type
9591 This is the type of the @code{mcron} service, whose value is an
9592 @code{mcron-configuration} object.
9594 This service type can be the target of a service extension that provides
9595 it additional job specifications (@pxref{Service Composition}). In
9596 other words, it is possible to define services that provide additional
9600 @deftp {Data Type} mcron-configuration
9601 Data type representing the configuration of mcron.
9604 @item @code{mcron} (default: @var{mcron2})
9605 The mcron package to use.
9608 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9609 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9610 specifications,, mcron, GNU@tie{}mcron}).
9616 @subsubsection Log Rotation
9619 @cindex log rotation
9621 Log files such as those found in @file{/var/log} tend to grow endlessly,
9622 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9623 their contents in separate files, possibly compressed. The @code{(gnu
9624 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9625 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9627 The example below defines an operating system that provides log rotation
9628 with the default settings, for commonly encountered log files.
9631 (use-modules (guix) (gnu))
9632 (use-service-modules admin mcron)
9633 (use-package-modules base idutils)
9637 (services (cons* (mcron-service)
9638 (service rottlog-service-type)
9642 @defvr {Scheme Variable} rottlog-service-type
9643 This is the type of the Rottlog service, whose value is a
9644 @code{rottlog-configuration} object.
9646 Other services can extend this one with new @code{log-rotation} objects
9647 (see below), thereby augmenting the set of files to be rotated.
9649 This service type can define mcron jobs (@pxref{Scheduled Job
9650 Execution}) to run the rottlog service.
9653 @deftp {Data Type} rottlog-configuration
9654 Data type representing the configuration of rottlog.
9657 @item @code{rottlog} (default: @code{rottlog})
9658 The Rottlog package to use.
9660 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9661 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9662 rottlog, GNU Rot[t]log Manual}).
9664 @item @code{rotations} (default: @code{%default-rotations})
9665 A list of @code{log-rotation} objects as defined below.
9668 This is a list of gexps where each gexp corresponds to an mcron job
9669 specification (@pxref{Scheduled Job Execution}).
9673 @deftp {Data Type} log-rotation
9674 Data type representing the rotation of a group of log files.
9676 Taking an example from the Rottlog manual (@pxref{Period Related File
9677 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
9683 (files '("/var/log/apache/*"))
9684 (options '("storedir apache-archives"
9690 The list of fields is as follows:
9693 @item @code{frequency} (default: @code{'weekly})
9694 The log rotation frequency, a symbol.
9697 The list of files or file glob patterns to rotate.
9699 @item @code{options} (default: @code{'()})
9700 The list of rottlog options for this rotation (@pxref{Configuration
9701 parameters,,, rottlog, GNU Rot[t]lg Manual}).
9703 @item @code{post-rotate} (default: @code{#f})
9704 Either @code{#f} or a gexp to execute once the rotation has completed.
9708 @defvr {Scheme Variable} %default-rotations
9709 Specifies weekly rotation of @var{%rotated-files} and
9710 a couple of other files.
9713 @defvr {Scheme Variable} %rotated-files
9714 The list of syslog-controlled files to be rotated. By default it is:
9715 @code{'("/var/log/messages" "/var/log/secure")}.
9718 @node Networking Services
9719 @subsubsection Networking Services
9721 The @code{(gnu services networking)} module provides services to configure
9722 the network interface.
9724 @cindex DHCP, networking service
9725 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9726 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9727 Protocol (DHCP) client, on all the non-loopback network interfaces.
9730 @defvr {Scheme Variable} static-networking-service-type
9731 This is the type for statically-configured network interfaces.
9732 @c TODO Document <static-networking> data structures.
9735 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9736 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9737 Return a service that starts @var{interface} with address @var{ip}. If
9738 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9739 it must be a string specifying the default network gateway.
9741 This procedure can be called several times, one for each network
9742 interface of interest. Behind the scenes what it does is extend
9743 @code{static-networking-service-type} with additional network interfaces
9750 @cindex network management
9751 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9752 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9753 management daemon that aims to simplify wired and wireless networking.
9755 This service adds the @var{wicd} package to the global profile, providing
9756 several commands to interact with the daemon and configure networking:
9757 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9758 and @command{wicd-curses} user interfaces.
9761 @cindex NetworkManager
9763 @defvr {Scheme Variable} network-manager-service-type
9764 This is the service type for the
9765 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9766 service. The value for this service type is a
9767 @code{network-manager-configuration} record.
9770 @deftp {Data Type} network-manager-configuration
9771 Data type representing the configuration of NetworkManager.
9774 @item @code{network-manager} (default: @code{network-manager})
9775 The NetworkManager package to use.
9777 @item @code{dns} (default: @code{"default"})
9778 Processing mode for DNS, which affects how NetworkManager uses the
9779 @code{resolv.conf} configuration file.
9783 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9784 provided by currently active connections.
9787 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9788 using a "split DNS" configuration if you are connected to a VPN, and
9789 then update @code{resolv.conf} to point to the local nameserver.
9792 NetworkManager will not modify @code{resolv.conf}.
9799 @deffn {Scheme Variable} connman-service-type
9800 This is the service type to run @url{https://01.org/connman,Connman},
9801 a network connection manager.
9803 Its value must be an
9804 @code{connman-configuration} record as in this example:
9807 (service connman-service-type
9808 (connman-configuration
9812 See below for details about @code{connman-configuration}.
9815 @deftp {Data Type} connman-configuration
9816 Data Type representing the configuration of connman.
9819 @item @code{connman} (default: @var{connman})
9820 The connman package to use.
9822 @item @code{disable-vpn?} (default: @code{#f})
9823 When true, enable connman's vpn plugin.
9827 @cindex WPA Supplicant
9828 @defvr {Scheme Variable} wpa-supplicant-service-type
9829 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9830 supplicant}, an authentication daemon required to authenticate against
9831 encrypted WiFi or ethernet networks. It is configured to listen for
9834 The value of this service is the @code{wpa-supplicant} package to use.
9835 Thus, it can be instantiated like this:
9838 (use-modules (gnu services networking))
9840 (service wpa-supplicant-service-type)
9845 @cindex real time clock
9846 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9847 [#:servers @var{%ntp-servers}] @
9848 [#:allow-large-adjustment? #f]
9849 Return a service that runs the daemon from @var{ntp}, the
9850 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9851 keep the system clock synchronized with that of @var{servers}.
9852 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9853 make an initial adjustment of more than 1,000 seconds.
9856 @defvr {Scheme Variable} %ntp-servers
9857 List of host names used as the default NTP servers.
9861 @deffn {Scheme variable} inetd-service-type
9862 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9863 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9864 connections on internet sockets, and lazily starts the specified server
9865 program when a connection is made on one of these sockets.
9867 The value of this service is an @code{inetd-configuration} object. The
9868 following example configures the @command{inetd} daemon to provide the
9869 built-in @command{echo} service, as well as an smtp service which
9870 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9871 gateway @code{hostname}:
9876 (inetd-configuration
9880 (socket-type 'stream)
9887 (socket-type 'stream)
9891 (program (file-append openssh "/bin/ssh"))
9893 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9894 "-W" "smtp-server:25" "user@@hostname")))))
9897 See below for more details about @code{inetd-configuration}.
9900 @deftp {Data Type} inetd-configuration
9901 Data type representing the configuration of @command{inetd}.
9904 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9905 The @command{inetd} executable to use.
9907 @item @code{entries} (default: @code{'()})
9908 A list of @command{inetd} service entries. Each entry should be created
9909 by the @code{inetd-entry} constructor.
9913 @deftp {Data Type} inetd-entry
9914 Data type representing an entry in the @command{inetd} configuration.
9915 Each entry corresponds to a socket where @command{inetd} will listen for
9919 @item @code{node} (default: @code{#f})
9920 Optional string, a comma-separated list of local addresses
9921 @command{inetd} should use when listening for this service.
9922 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9923 description of all options.
9925 A string, the name must correspond to an entry in @code{/etc/services}.
9926 @item @code{socket-type}
9927 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9929 @item @code{protocol}
9930 A string, must correspond to an entry in @code{/etc/protocols}.
9931 @item @code{wait?} (default: @code{#t})
9932 Whether @command{inetd} should wait for the server to exit before
9933 listening to new service requests.
9935 A string containing the user (and, optionally, group) name of the user
9936 as whom the server should run. The group name can be specified in a
9937 suffix, separated by a colon or period, i.e. @code{"user"},
9938 @code{"user:group"} or @code{"user.group"}.
9939 @item @code{program} (default: @code{"internal"})
9940 The server program which will serve the requests, or @code{"internal"}
9941 if @command{inetd} should use a built-in service.
9942 @item @code{arguments} (default: @code{'()})
9943 A list strings or file-like objects, which are the server program's
9944 arguments, starting with the zeroth argument, i.e. the name of the
9945 program itself. For @command{inetd}'s internal services, this entry
9946 must be @code{'()} or @code{'("internal")}.
9949 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9950 detailed discussion of each configuration field.
9954 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9955 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9958 The daemon runs as the @code{tor} unprivileged user. It is passed
9959 @var{config-file}, a file-like object, with an additional @code{User tor} line
9960 and lines for hidden services added via @code{tor-hidden-service}. Run
9961 @command{man tor} for information about the configuration file.
9964 @cindex hidden service
9965 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9966 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9967 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9970 '((22 "127.0.0.1:22")
9971 (80 "127.0.0.1:8080"))
9974 In this example, port 22 of the hidden service is mapped to local port 22, and
9975 port 80 is mapped to local port 8080.
9977 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9978 the @file{hostname} file contains the @code{.onion} host name for the hidden
9981 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9982 project's documentation} for more information.
9985 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9986 [#:interface "127.0.0.1"] [#:port 6667] @
9987 [#:extra-settings ""]
9988 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9989 acts as a gateway between IRC and chat networks.
9991 The daemon will listen to the interface corresponding to the IP address
9992 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9993 local clients can connect, whereas @code{0.0.0.0} means that connections can
9994 come from any networking interface.
9996 In addition, @var{extra-settings} specifies a string to append to the
10000 Furthermore, @code{(gnu services ssh)} provides the following services.
10004 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10005 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10006 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10007 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10008 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10009 [#:public-key-authentication? #t] [#:initialize? #t]
10010 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10011 @var{host-key} must designate a file containing the host key, and readable
10014 When @var{daemonic?} is true, @command{lshd} will detach from the
10015 controlling terminal and log its output to syslogd, unless one sets
10016 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10017 depend on existence of syslogd service. When @var{pid-file?} is true,
10018 @command{lshd} writes its PID to the file called @var{pid-file}.
10020 When @var{initialize?} is true, automatically create the seed and host key
10021 upon service activation if they do not exist yet. This may take long and
10022 require interaction.
10024 When @var{initialize?} is false, it is up to the user to initialize the
10025 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10026 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10027 basics,,, lsh, LSH Manual}).
10029 When @var{interfaces} is empty, lshd listens for connections on all the
10030 network interfaces; otherwise, @var{interfaces} must be a list of host names
10033 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10034 passwords, and @var{root-login?} specifies whether to accept log-ins as
10037 The other options should be self-descriptive.
10042 @deffn {Scheme Variable} openssh-service-type
10043 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10044 shell daemon, @command{sshd}. Its value must be an
10045 @code{openssh-configuration} record as in this example:
10048 (service openssh-service-type
10049 (openssh-configuration
10050 (x11-forwarding? #t)
10051 (permit-root-login 'without-password)))
10054 See below for details about @code{openssh-configuration}.
10057 @deftp {Data Type} openssh-configuration
10058 This is the configuration record for OpenSSH's @command{sshd}.
10061 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10062 Name of the file where @command{sshd} writes its PID.
10064 @item @code{port-number} (default: @code{22})
10065 TCP port on which @command{sshd} listens for incoming connections.
10067 @item @code{permit-root-login} (default: @code{#f})
10068 This field determines whether and when to allow logins as root. If
10069 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10070 If it's the symbol @code{'without-password}, then root logins are
10071 permitted but not with password-based authentication.
10073 @item @code{allow-empty-passwords?} (default: @code{#f})
10074 When true, users with empty passwords may log in. When false, they may
10077 @item @code{password-authentication?} (default: @code{#t})
10078 When true, users may log in with their password. When false, they have
10079 other authentication methods.
10081 @item @code{public-key-authentication?} (default: @code{#t})
10082 When true, users may log in using public key authentication. When
10083 false, users have to use other authentication method.
10085 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10086 This is used only by protocol version 2.
10088 @item @code{x11-forwarding?} (default: @code{#f})
10089 When true, forwarding of X11 graphical client connections is
10090 enabled---in other words, @command{ssh} options @option{-X} and
10091 @option{-Y} will work.
10093 @item @code{challenge-response-authentication?} (default: @code{#f})
10094 Specifies whether challenge response authentication is allowed (e.g. via
10097 @item @code{use-pam?} (default: @code{#t})
10098 Enables the Pluggable Authentication Module interface. If set to
10099 @code{#t}, this will enable PAM authentication using
10100 @code{challenge-response-authentication?} and
10101 @code{password-authentication?}, in addition to PAM account and session
10102 module processing for all authentication types.
10104 Because PAM challenge response authentication usually serves an
10105 equivalent role to password authentication, you should disable either
10106 @code{challenge-response-authentication?} or
10107 @code{password-authentication?}.
10109 @item @code{print-last-log?} (default: @code{#t})
10110 Specifies whether @command{sshd} should print the date and time of the
10111 last user login when a user logs in interactively.
10113 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10114 Configures external subsystems (e.g. file transfer daemon).
10116 This is a list of two-element lists, each of which containing the
10117 subsystem name and a command (with optional arguments) to execute upon
10120 The command @command{internal-sftp} implements an in-process SFTP
10121 server. Alternately, one can specify the @command{sftp-server} command:
10123 (service openssh-service-type
10124 (openssh-configuration
10126 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10131 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10132 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10133 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10136 For example, to specify a Dropbear service listening on port 1234, add
10137 this call to the operating system's @code{services} field:
10140 (dropbear-service (dropbear-configuration
10141 (port-number 1234)))
10145 @deftp {Data Type} dropbear-configuration
10146 This data type represents the configuration of a Dropbear SSH daemon.
10149 @item @code{dropbear} (default: @var{dropbear})
10150 The Dropbear package to use.
10152 @item @code{port-number} (default: 22)
10153 The TCP port where the daemon waits for incoming connections.
10155 @item @code{syslog-output?} (default: @code{#t})
10156 Whether to enable syslog output.
10158 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10159 File name of the daemon's PID file.
10161 @item @code{root-login?} (default: @code{#f})
10162 Whether to allow @code{root} logins.
10164 @item @code{allow-empty-passwords?} (default: @code{#f})
10165 Whether to allow empty passwords.
10167 @item @code{password-authentication?} (default: @code{#t})
10168 Whether to enable password-based authentication.
10172 @defvr {Scheme Variable} %facebook-host-aliases
10173 This variable contains a string for use in @file{/etc/hosts}
10174 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10175 line contains a entry that maps a known server name of the Facebook
10176 on-line service---e.g., @code{www.facebook.com}---to the local
10177 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10179 This variable is typically used in the @code{hosts-file} field of an
10180 @code{operating-system} declaration (@pxref{operating-system Reference,
10181 @file{/etc/hosts}}):
10184 (use-modules (gnu) (guix))
10187 (host-name "mymachine")
10190 ;; Create a /etc/hosts file with aliases for "localhost"
10191 ;; and "mymachine", as well as for Facebook servers.
10192 (plain-file "hosts"
10193 (string-append (local-host-aliases host-name)
10194 %facebook-host-aliases))))
10197 This mechanism can prevent programs running locally, such as Web
10198 browsers, from accessing Facebook.
10201 The @code{(gnu services avahi)} provides the following definition.
10203 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10204 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10205 [#:ipv6? #t] [#:wide-area? #f] @
10206 [#:domains-to-browse '()] [#:debug? #f]
10207 Return a service that runs @command{avahi-daemon}, a system-wide
10208 mDNS/DNS-SD responder that allows for service discovery and
10209 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10210 extends the name service cache daemon (nscd) so that it can resolve
10211 @code{.local} host names using
10212 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10213 add the @var{avahi} package to the system profile so that commands such as
10214 @command{avahi-browse} are directly usable.
10216 If @var{host-name} is different from @code{#f}, use that as the host name to
10217 publish for this machine; otherwise, use the machine's actual host name.
10219 When @var{publish?} is true, publishing of host names and services is allowed;
10220 in particular, avahi-daemon will publish the machine's host name and IP
10221 address via mDNS on the local network.
10223 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10225 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10229 @deffn {Scheme Variable} openvswitch-service-type
10230 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10231 service, whose value should be an @code{openvswitch-configuration}
10235 @deftp {Data Type} openvswitch-configuration
10236 Data type representing the configuration of Open vSwitch, a multilayer
10237 virtual switch which is designed to enable massive network automation
10238 through programmatic extension.
10241 @item @code{package} (default: @var{openvswitch})
10242 Package object of the Open vSwitch.
10248 @subsubsection X Window
10251 @cindex X Window System
10252 Support for the X Window graphical display system---specifically
10253 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10254 there is no @code{xorg-service} procedure. Instead, the X server is
10255 started by the @dfn{login manager}, currently SLiM.
10257 @deftp {Data Type} sddm-configuration
10258 This is the data type representing the sddm service configuration.
10261 @item @code{display-server} (default: "x11")
10262 Select display server to use for the greeter. Valid values are "x11"
10265 @item @code{numlock} (default: "on")
10266 Valid values are "on", "off" or "none".
10268 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10269 Command to run when halting.
10271 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10272 Command to run when rebooting.
10274 @item @code{theme} (default "maldives")
10275 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10277 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10278 Directory to look for themes.
10280 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10281 Directory to look for faces.
10283 @item @code{default-path} (default "/run/current-system/profile/bin")
10284 Default PATH to use.
10286 @item @code{minimum-uid} (default 1000)
10287 Minimum UID to display in SDDM.
10289 @item @code{maximum-uid} (default 2000)
10290 Maximum UID to display in SDDM
10292 @item @code{remember-last-user?} (default #t)
10293 Remember last user.
10295 @item @code{remember-last-session?} (default #t)
10296 Remember last session.
10298 @item @code{hide-users} (default "")
10299 Usernames to hide from SDDM greeter.
10301 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10302 Users with shells listed will be hidden from the SDDM greeter.
10304 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10305 Script to run before starting a wayland session.
10307 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10308 Directory to look for desktop files starting wayland sessions.
10310 @item @code{xorg-server-path} (default @code{xorg-start-command})
10311 Path to xorg-server.
10313 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10316 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10319 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10320 Script to run after starting xorg-server.
10322 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10323 Script to run before stopping xorg-server.
10325 @item @code{xsession-command} (default: @code{xinitr })
10326 Script to run before starting a X session.
10328 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10329 Directory to look for desktop files starting X sessions.
10331 @item @code{minimum-vt} (default: 7)
10334 @item @code{xserver-arguments} (default "-nolisten tcp")
10335 Arguments to pass to xorg-server.
10337 @item @code{auto-login-user} (default "")
10338 User to use for auto-login.
10340 @item @code{auto-login-session} (default "")
10341 Desktop file to use for auto-login.
10343 @item @code{relogin?} (default #f)
10344 Relogin after logout.
10349 @cindex login manager
10350 @deffn {Scheme Procedure} sddm-service config
10351 Return a service that spawns the SDDM graphical login manager for config of
10352 type @code{<sddm-configuration>}.
10355 (sddm-service (sddm-configuration
10356 (auto-login-user "Alice")
10357 (auto-login-session "xfce.desktop")))
10361 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10362 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10363 [#:theme @var{%default-slim-theme}] @
10364 [#:theme-name @var{%default-slim-theme-name}]
10365 Return a service that spawns the SLiM graphical login manager, which in
10366 turn starts the X display server with @var{startx}, a command as returned by
10367 @code{xorg-start-command}.
10371 SLiM automatically looks for session types described by the @file{.desktop}
10372 files in @file{/run/current-system/profile/share/xsessions} and allows users
10373 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10374 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10375 adding them to the system-wide set of packages automatically makes them
10376 available at the log-in screen.
10378 In addition, @file{~/.xsession} files are honored. When available,
10379 @file{~/.xsession} must be an executable that starts a window manager
10380 and/or other X clients.
10382 When @var{allow-empty-passwords?} is true, allow logins with an empty
10383 password. When @var{auto-login?} is true, log in automatically as
10384 @var{default-user}.
10386 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10387 @var{theme} must be a gexp denoting the name of a directory containing the
10388 theme to use. In that case, @var{theme-name} specifies the name of the
10392 @defvr {Scheme Variable} %default-theme
10393 @defvrx {Scheme Variable} %default-theme-name
10394 The G-Expression denoting the default SLiM theme and its name.
10397 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10398 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10399 Return a derivation that builds a @var{guile} script to start the X server
10400 from @var{xorg-server}. @var{configuration-file} is the server configuration
10401 file or a derivation that builds it; when omitted, the result of
10402 @code{xorg-configuration-file} is used.
10404 Usually the X server is started by a login manager.
10407 @deffn {Scheme Procedure} xorg-configuration-file @
10408 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10409 Return a configuration file for the Xorg server containing search paths for
10410 all the common drivers.
10412 @var{drivers} must be either the empty list, in which case Xorg chooses a
10413 graphics driver automatically, or a list of driver names that will be tried in
10414 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10416 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10417 appropriate screen resolution; otherwise, it must be a list of
10418 resolutions---e.g., @code{((1024 768) (640 480))}.
10420 Last, @var{extra-config} is a list of strings or objects appended to the
10421 @code{text-file*} argument list. It is used to pass extra text to be added
10422 verbatim to the configuration file.
10425 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10426 Add @var{package}, a package for a screen-locker or screen-saver whose
10427 command is @var{program}, to the set of setuid programs and add a PAM entry
10428 for it. For example:
10431 (screen-locker-service xlockmore "xlock")
10434 makes the good ol' XlockMore usable.
10438 @node Printing Services
10439 @subsubsection Printing Services
10441 @cindex printer support with CUPS
10442 The @code{(gnu services cups)} module provides a Guix service definition
10443 for the CUPS printing service. To add printer support to a GuixSD
10444 system, add a @code{cups-service} to the operating system definition:
10446 @deffn {Scheme Variable} cups-service-type
10447 The service type for the CUPS print server. Its value should be a valid
10448 CUPS configuration (see below). To use the default settings, simply
10451 (service cups-service-type)
10455 The CUPS configuration controls the basic things about your CUPS
10456 installation: what interfaces it listens on, what to do if a print job
10457 fails, how much logging to do, and so on. To actually add a printer,
10458 you have to visit the @url{http://localhost:631} URL, or use a tool such
10459 as GNOME's printer configuration services. By default, configuring a
10460 CUPS service will generate a self-signed certificate if needed, for
10461 secure connections to the print server.
10463 Suppose you want to enable the Web interface of CUPS and also add
10464 support for HP printers @i{via} the @code{hplip} package. You can do
10465 that directly, like this (you need to use the @code{(gnu packages cups)}
10469 (service cups-service-type
10470 (cups-configuration
10471 (web-interface? #t)
10473 (list cups-filters hplip))))
10476 The available configuration parameters follow. Each parameter
10477 definition is preceded by its type; for example, @samp{string-list foo}
10478 indicates that the @code{foo} parameter should be specified as a list of
10479 strings. There is also a way to specify the configuration as a string,
10480 if you have an old @code{cupsd.conf} file that you want to port over
10481 from some other system; see the end for more details.
10483 @c The following documentation was initially generated by
10484 @c (generate-documentation) in (gnu services cups). Manually maintained
10485 @c documentation is better, so we shouldn't hesitate to edit below as
10486 @c needed. However if the change you want to make to this documentation
10487 @c can be done in an automated way, it's probably easier to change
10488 @c (generate-documentation) than to make it below and have to deal with
10489 @c the churn as CUPS updates.
10492 Available @code{cups-configuration} fields are:
10494 @deftypevr {@code{cups-configuration} parameter} package cups
10498 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10499 Drivers and other extensions to the CUPS package.
10502 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10503 Configuration of where to write logs, what directories to use for print
10504 spools, and related privileged configuration parameters.
10506 Available @code{files-configuration} fields are:
10508 @deftypevr {@code{files-configuration} parameter} log-location access-log
10509 Defines the access log filename. Specifying a blank filename disables
10510 access log generation. The value @code{stderr} causes log entries to be
10511 sent to the standard error file when the scheduler is running in the
10512 foreground, or to the system log daemon when run in the background. The
10513 value @code{syslog} causes log entries to be sent to the system log
10514 daemon. The server name may be included in filenames using the string
10515 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10517 Defaults to @samp{"/var/log/cups/access_log"}.
10520 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10521 Where CUPS should cache data.
10523 Defaults to @samp{"/var/cache/cups"}.
10526 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10527 Specifies the permissions for all configuration files that the scheduler
10530 Note that the permissions for the printers.conf file are currently
10531 masked to only allow access from the scheduler user (typically root).
10532 This is done because printer device URIs sometimes contain sensitive
10533 authentication information that should not be generally known on the
10534 system. There is no way to disable this security feature.
10536 Defaults to @samp{"0640"}.
10539 @deftypevr {@code{files-configuration} parameter} log-location error-log
10540 Defines the error log filename. Specifying a blank filename disables
10541 access log generation. The value @code{stderr} causes log entries to be
10542 sent to the standard error file when the scheduler is running in the
10543 foreground, or to the system log daemon when run in the background. The
10544 value @code{syslog} causes log entries to be sent to the system log
10545 daemon. The server name may be included in filenames using the string
10546 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10548 Defaults to @samp{"/var/log/cups/error_log"}.
10551 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10552 Specifies which errors are fatal, causing the scheduler to exit. The
10557 No errors are fatal.
10560 All of the errors below are fatal.
10563 Browsing initialization errors are fatal, for example failed connections
10564 to the DNS-SD daemon.
10567 Configuration file syntax errors are fatal.
10570 Listen or Port errors are fatal, except for IPv6 failures on the
10571 loopback or @code{any} addresses.
10574 Log file creation or write errors are fatal.
10577 Bad startup file permissions are fatal, for example shared TLS
10578 certificate and key files with world-read permissions.
10581 Defaults to @samp{"all -browse"}.
10584 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10585 Specifies whether the file pseudo-device can be used for new printer
10586 queues. The URI @uref{file:///dev/null} is always allowed.
10588 Defaults to @samp{#f}.
10591 @deftypevr {@code{files-configuration} parameter} string group
10592 Specifies the group name or ID that will be used when executing external
10595 Defaults to @samp{"lp"}.
10598 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10599 Specifies the permissions for all log files that the scheduler writes.
10601 Defaults to @samp{"0644"}.
10604 @deftypevr {@code{files-configuration} parameter} log-location page-log
10605 Defines the page log filename. Specifying a blank filename disables
10606 access log generation. The value @code{stderr} causes log entries to be
10607 sent to the standard error file when the scheduler is running in the
10608 foreground, or to the system log daemon when run in the background. The
10609 value @code{syslog} causes log entries to be sent to the system log
10610 daemon. The server name may be included in filenames using the string
10611 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10613 Defaults to @samp{"/var/log/cups/page_log"}.
10616 @deftypevr {@code{files-configuration} parameter} string remote-root
10617 Specifies the username that is associated with unauthenticated accesses
10618 by clients claiming to be the root user. The default is @code{remroot}.
10620 Defaults to @samp{"remroot"}.
10623 @deftypevr {@code{files-configuration} parameter} file-name request-root
10624 Specifies the directory that contains print jobs and other HTTP request
10627 Defaults to @samp{"/var/spool/cups"}.
10630 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10631 Specifies the level of security sandboxing that is applied to print
10632 filters, backends, and other child processes of the scheduler; either
10633 @code{relaxed} or @code{strict}. This directive is currently only
10634 used/supported on macOS.
10636 Defaults to @samp{strict}.
10639 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10640 Specifies the location of TLS certificates and private keys. CUPS will
10641 look for public and private keys in this directory: a @code{.crt} files
10642 for PEM-encoded certificates and corresponding @code{.key} files for
10643 PEM-encoded private keys.
10645 Defaults to @samp{"/etc/cups/ssl"}.
10648 @deftypevr {@code{files-configuration} parameter} file-name server-root
10649 Specifies the directory containing the server configuration files.
10651 Defaults to @samp{"/etc/cups"}.
10654 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10655 Specifies whether the scheduler calls fsync(2) after writing
10656 configuration or state files.
10658 Defaults to @samp{#f}.
10661 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10662 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10665 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10666 Specifies the directory where temporary files are stored.
10668 Defaults to @samp{"/var/spool/cups/tmp"}.
10671 @deftypevr {@code{files-configuration} parameter} string user
10672 Specifies the user name or ID that is used when running external
10675 Defaults to @samp{"lp"}.
10679 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10680 Specifies the logging level for the AccessLog file. The @code{config}
10681 level logs when printers and classes are added, deleted, or modified and
10682 when configuration files are accessed or updated. The @code{actions}
10683 level logs when print jobs are submitted, held, released, modified, or
10684 canceled, and any of the conditions for @code{config}. The @code{all}
10685 level logs all requests.
10687 Defaults to @samp{actions}.
10690 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10691 Specifies whether to purge job history data automatically when it is no
10692 longer required for quotas.
10694 Defaults to @samp{#f}.
10697 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10698 Specifies which protocols to use for local printer sharing.
10700 Defaults to @samp{dnssd}.
10703 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10704 Specifies whether the CUPS web interface is advertised.
10706 Defaults to @samp{#f}.
10709 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10710 Specifies whether shared printers are advertised.
10712 Defaults to @samp{#f}.
10715 @deftypevr {@code{cups-configuration} parameter} string classification
10716 Specifies the security classification of the server. Any valid banner
10717 name can be used, including "classified", "confidential", "secret",
10718 "topsecret", and "unclassified", or the banner can be omitted to disable
10719 secure printing functions.
10721 Defaults to @samp{""}.
10724 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10725 Specifies whether users may override the classification (cover page) of
10726 individual print jobs using the @code{job-sheets} option.
10728 Defaults to @samp{#f}.
10731 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10732 Specifies the default type of authentication to use.
10734 Defaults to @samp{Basic}.
10737 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10738 Specifies whether encryption will be used for authenticated requests.
10740 Defaults to @samp{Required}.
10743 @deftypevr {@code{cups-configuration} parameter} string default-language
10744 Specifies the default language to use for text and web content.
10746 Defaults to @samp{"en"}.
10749 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10750 Specifies the default paper size for new print queues. @samp{"Auto"}
10751 uses a locale-specific default, while @samp{"None"} specifies there is
10752 no default paper size. Specific size names are typically
10753 @samp{"Letter"} or @samp{"A4"}.
10755 Defaults to @samp{"Auto"}.
10758 @deftypevr {@code{cups-configuration} parameter} string default-policy
10759 Specifies the default access policy to use.
10761 Defaults to @samp{"default"}.
10764 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10765 Specifies whether local printers are shared by default.
10767 Defaults to @samp{#t}.
10770 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10771 Specifies the delay for updating of configuration and state files, in
10772 seconds. A value of 0 causes the update to happen as soon as possible,
10773 typically within a few milliseconds.
10775 Defaults to @samp{30}.
10778 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10779 Specifies what to do when an error occurs. Possible values are
10780 @code{abort-job}, which will discard the failed print job;
10781 @code{retry-job}, which will retry the job at a later time;
10782 @code{retry-this-job}, which retries the failed job immediately; and
10783 @code{stop-printer}, which stops the printer.
10785 Defaults to @samp{stop-printer}.
10788 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10789 Specifies the maximum cost of filters that are run concurrently, which
10790 can be used to minimize disk, memory, and CPU resource problems. A
10791 limit of 0 disables filter limiting. An average print to a
10792 non-PostScript printer needs a filter limit of about 200. A PostScript
10793 printer needs about half that (100). Setting the limit below these
10794 thresholds will effectively limit the scheduler to printing a single job
10797 Defaults to @samp{0}.
10800 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10801 Specifies the scheduling priority of filters that are run to print a
10802 job. The nice value ranges from 0, the highest priority, to 19, the
10805 Defaults to @samp{0}.
10808 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10809 Specifies whether to do reverse lookups on connecting clients. The
10810 @code{double} setting causes @code{cupsd} to verify that the hostname
10811 resolved from the address matches one of the addresses returned for that
10812 hostname. Double lookups also prevent clients with unregistered
10813 addresses from connecting to your server. Only set this option to
10814 @code{#t} or @code{double} if absolutely required.
10816 Defaults to @samp{#f}.
10819 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10820 Specifies the number of seconds to wait before killing the filters and
10821 backend associated with a canceled or held job.
10823 Defaults to @samp{30}.
10826 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10827 Specifies the interval between retries of jobs in seconds. This is
10828 typically used for fax queues but can also be used with normal print
10829 queues whose error policy is @code{retry-job} or
10830 @code{retry-current-job}.
10832 Defaults to @samp{30}.
10835 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10836 Specifies the number of retries that are done for jobs. This is
10837 typically used for fax queues but can also be used with normal print
10838 queues whose error policy is @code{retry-job} or
10839 @code{retry-current-job}.
10841 Defaults to @samp{5}.
10844 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10845 Specifies whether to support HTTP keep-alive connections.
10847 Defaults to @samp{#t}.
10850 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10851 Specifies how long an idle client connection remains open, in seconds.
10853 Defaults to @samp{30}.
10856 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10857 Specifies the maximum size of print files, IPP requests, and HTML form
10858 data. A limit of 0 disables the limit check.
10860 Defaults to @samp{0}.
10863 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10864 Listens on the specified interfaces for connections. Valid values are
10865 of the form @var{address}:@var{port}, where @var{address} is either an
10866 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10867 indicate all addresses. Values can also be file names of local UNIX
10868 domain sockets. The Listen directive is similar to the Port directive
10869 but allows you to restrict access to specific interfaces or networks.
10872 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10873 Specifies the number of pending connections that will be allowed. This
10874 normally only affects very busy servers that have reached the MaxClients
10875 limit, but can also be triggered by large numbers of simultaneous
10876 connections. When the limit is reached, the operating system will
10877 refuse additional connections until the scheduler can accept the pending
10880 Defaults to @samp{128}.
10883 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10884 Specifies a set of additional access controls.
10886 Available @code{location-access-controls} fields are:
10888 @deftypevr {@code{location-access-controls} parameter} file-name path
10889 Specifies the URI path to which the access control applies.
10892 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10893 Access controls for all access to this path, in the same format as the
10894 @code{access-controls} of @code{operation-access-control}.
10896 Defaults to @samp{()}.
10899 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10900 Access controls for method-specific access to this path.
10902 Defaults to @samp{()}.
10904 Available @code{method-access-controls} fields are:
10906 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10907 If @code{#t}, apply access controls to all methods except the listed
10908 methods. Otherwise apply to only the listed methods.
10910 Defaults to @samp{#f}.
10913 @deftypevr {@code{method-access-controls} parameter} method-list methods
10914 Methods to which this access control applies.
10916 Defaults to @samp{()}.
10919 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10920 Access control directives, as a list of strings. Each string should be
10921 one directive, such as "Order allow,deny".
10923 Defaults to @samp{()}.
10928 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10929 Specifies the number of debugging messages that are retained for logging
10930 if an error occurs in a print job. Debug messages are logged regardless
10931 of the LogLevel setting.
10933 Defaults to @samp{100}.
10936 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10937 Specifies the level of logging for the ErrorLog file. The value
10938 @code{none} stops all logging while @code{debug2} logs everything.
10940 Defaults to @samp{info}.
10943 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10944 Specifies the format of the date and time in the log files. The value
10945 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10947 Defaults to @samp{standard}.
10950 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10951 Specifies the maximum number of simultaneous clients that are allowed by
10954 Defaults to @samp{100}.
10957 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10958 Specifies the maximum number of simultaneous clients that are allowed
10959 from a single address.
10961 Defaults to @samp{100}.
10964 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10965 Specifies the maximum number of copies that a user can print of each
10968 Defaults to @samp{9999}.
10971 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10972 Specifies the maximum time a job may remain in the @code{indefinite}
10973 hold state before it is canceled. A value of 0 disables cancellation of
10976 Defaults to @samp{0}.
10979 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10980 Specifies the maximum number of simultaneous jobs that are allowed. Set
10981 to 0 to allow an unlimited number of jobs.
10983 Defaults to @samp{500}.
10986 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10987 Specifies the maximum number of simultaneous jobs that are allowed per
10988 printer. A value of 0 allows up to MaxJobs jobs per printer.
10990 Defaults to @samp{0}.
10993 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10994 Specifies the maximum number of simultaneous jobs that are allowed per
10995 user. A value of 0 allows up to MaxJobs jobs per user.
10997 Defaults to @samp{0}.
11000 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11001 Specifies the maximum time a job may take to print before it is
11002 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11004 Defaults to @samp{10800}.
11007 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11008 Specifies the maximum size of the log files before they are rotated, in
11009 bytes. The value 0 disables log rotation.
11011 Defaults to @samp{1048576}.
11014 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11015 Specifies the maximum amount of time to allow between files in a
11016 multiple file print job, in seconds.
11018 Defaults to @samp{300}.
11021 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11022 Specifies the format of PageLog lines. Sequences beginning with percent
11023 (@samp{%}) characters are replaced with the corresponding information,
11024 while all other characters are copied literally. The following percent
11025 sequences are recognized:
11029 insert a single percent character
11032 insert the value of the specified IPP attribute
11035 insert the number of copies for the current page
11038 insert the current page number
11041 insert the current date and time in common log format
11047 insert the printer name
11050 insert the username
11053 A value of the empty string disables page logging. The string @code{%p
11054 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11055 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11058 Defaults to @samp{""}.
11061 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11062 Passes the specified environment variable(s) to child processes; a list
11065 Defaults to @samp{()}.
11068 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11069 Specifies named access control policies.
11071 Available @code{policy-configuration} fields are:
11073 @deftypevr {@code{policy-configuration} parameter} string name
11074 Name of the policy.
11077 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11078 Specifies an access list for a job's private values. @code{@@ACL} maps
11079 to the printer's requesting-user-name-allowed or
11080 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11081 owner. @code{@@SYSTEM} maps to the groups listed for the
11082 @code{system-group} field of the @code{files-config} configuration,
11083 which is reified into the @code{cups-files.conf(5)} file. Other
11084 possible elements of the access list include specific user names, and
11085 @code{@@@var{group}} to indicate members of a specific group. The
11086 access list may also be simply @code{all} or @code{default}.
11088 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11091 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11092 Specifies the list of job values to make private, or @code{all},
11093 @code{default}, or @code{none}.
11095 Defaults to @samp{"job-name job-originating-host-name
11096 job-originating-user-name phone"}.
11099 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11100 Specifies an access list for a subscription's private values.
11101 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11102 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11103 owner. @code{@@SYSTEM} maps to the groups listed for the
11104 @code{system-group} field of the @code{files-config} configuration,
11105 which is reified into the @code{cups-files.conf(5)} file. Other
11106 possible elements of the access list include specific user names, and
11107 @code{@@@var{group}} to indicate members of a specific group. The
11108 access list may also be simply @code{all} or @code{default}.
11110 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11113 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11114 Specifies the list of job values to make private, or @code{all},
11115 @code{default}, or @code{none}.
11117 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11118 notify-subscriber-user-name notify-user-data"}.
11121 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11122 Access control by IPP operation.
11124 Defaults to @samp{()}.
11128 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11129 Specifies whether job files (documents) are preserved after a job is
11130 printed. If a numeric value is specified, job files are preserved for
11131 the indicated number of seconds after printing. Otherwise a boolean
11132 value applies indefinitely.
11134 Defaults to @samp{86400}.
11137 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11138 Specifies whether the job history is preserved after a job is printed.
11139 If a numeric value is specified, the job history is preserved for the
11140 indicated number of seconds after printing. If @code{#t}, the job
11141 history is preserved until the MaxJobs limit is reached.
11143 Defaults to @samp{#t}.
11146 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11147 Specifies the amount of time to wait for job completion before
11148 restarting the scheduler.
11150 Defaults to @samp{30}.
11153 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11154 Specifies the maximum amount of memory to use when converting documents
11155 into bitmaps for a printer.
11157 Defaults to @samp{"128m"}.
11160 @deftypevr {@code{cups-configuration} parameter} string server-admin
11161 Specifies the email address of the server administrator.
11163 Defaults to @samp{"root@@localhost.localdomain"}.
11166 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11167 The ServerAlias directive is used for HTTP Host header validation when
11168 clients connect to the scheduler from external interfaces. Using the
11169 special name @code{*} can expose your system to known browser-based DNS
11170 rebinding attacks, even when accessing sites through a firewall. If the
11171 auto-discovery of alternate names does not work, we recommend listing
11172 each alternate name with a ServerAlias directive instead of using
11175 Defaults to @samp{*}.
11178 @deftypevr {@code{cups-configuration} parameter} string server-name
11179 Specifies the fully-qualified host name of the server.
11181 Defaults to @samp{"localhost"}.
11184 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11185 Specifies what information is included in the Server header of HTTP
11186 responses. @code{None} disables the Server header. @code{ProductOnly}
11187 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11188 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11189 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11190 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11191 2.0.0 (@var{uname}) IPP/2.0}.
11193 Defaults to @samp{Minimal}.
11196 @deftypevr {@code{cups-configuration} parameter} string set-env
11197 Set the specified environment variable to be passed to child processes.
11199 Defaults to @samp{"variable value"}.
11202 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11203 Listens on the specified interfaces for encrypted connections. Valid
11204 values are of the form @var{address}:@var{port}, where @var{address} is
11205 either an IPv6 address enclosed in brackets, an IPv4 address, or
11206 @code{*} to indicate all addresses.
11208 Defaults to @samp{()}.
11211 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11212 Sets encryption options. By default, CUPS only supports encryption
11213 using TLS v1.0 or higher using known secure cipher suites. The
11214 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11215 required for some older clients that do not implement newer ones. The
11216 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11217 older clients that do not support TLS v1.0.
11219 Defaults to @samp{()}.
11222 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11223 Specifies whether the scheduler requires clients to strictly adhere to
11224 the IPP specifications.
11226 Defaults to @samp{#f}.
11229 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11230 Specifies the HTTP request timeout, in seconds.
11232 Defaults to @samp{300}.
11236 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11237 Specifies whether the web interface is enabled.
11239 Defaults to @samp{#f}.
11242 At this point you're probably thinking ``oh dear, Guix manual, I like
11243 you but you can stop already with the configuration options''. Indeed.
11244 However, one more point: it could be that you have an existing
11245 @code{cupsd.conf} that you want to use. In that case, you can pass an
11246 @code{opaque-cups-configuration} as the configuration of a
11247 @code{cups-service-type}.
11249 Available @code{opaque-cups-configuration} fields are:
11251 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11255 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11256 The contents of the @code{cupsd.conf}, as a string.
11259 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11260 The contents of the @code{cups-files.conf} file, as a string.
11263 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11264 strings of the same name, you could instantiate a CUPS service like
11268 (service cups-service-type
11269 (opaque-cups-configuration
11270 (cupsd.conf cupsd.conf)
11271 (cups-files.conf cups-files.conf)))
11275 @node Desktop Services
11276 @subsubsection Desktop Services
11278 The @code{(gnu services desktop)} module provides services that are
11279 usually useful in the context of a ``desktop'' setup---that is, on a
11280 machine running a graphical display server, possibly with graphical user
11281 interfaces, etc. It also defines services that provide specific desktop
11282 environments like GNOME and XFCE.
11284 To simplify things, the module defines a variable containing the set of
11285 services that users typically expect on a machine with a graphical
11286 environment and networking:
11288 @defvr {Scheme Variable} %desktop-services
11289 This is a list of services that builds upon @var{%base-services} and
11290 adds or adjusts services for a typical ``desktop'' setup.
11292 In particular, it adds a graphical login manager (@pxref{X Window,
11293 @code{slim-service}}), screen lockers,
11294 a network management tool (@pxref{Networking
11295 Services, @code{wicd-service}}), energy and color management services,
11296 the @code{elogind} login and seat manager, the Polkit privilege service,
11297 the GeoClue location service, an NTP client (@pxref{Networking
11298 Services}), the Avahi daemon, and has the name service switch service
11299 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11303 The @var{%desktop-services} variable can be used as the @code{services}
11304 field of an @code{operating-system} declaration (@pxref{operating-system
11305 Reference, @code{services}}).
11307 Additionally, the @code{gnome-desktop-service} and
11308 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11309 system. To ``add GNOME'' means that system-level services like the
11310 backlight adjustment helpers and the power management utilities are
11311 added to the system, extending @code{polkit} and @code{dbus}
11312 appropriately, allowing GNOME to operate with elevated privileges on a
11313 limited number of special-purpose system interfaces. Additionally,
11314 adding a service made by @code{gnome-desktop-service} adds the GNOME
11315 metapackage to the system profile. Likewise, adding the XFCE service
11316 not only adds the @code{xfce} metapackage to the system profile, but it
11317 also gives the Thunar file manager the ability to open a ``root-mode''
11318 file management window, if the user authenticates using the
11319 administrator's password via the standard polkit graphical interface.
11321 @deffn {Scheme Procedure} gnome-desktop-service
11322 Return a service that adds the @code{gnome} package to the system
11323 profile, and extends polkit with the actions from
11324 @code{gnome-settings-daemon}.
11327 @deffn {Scheme Procedure} xfce-desktop-service
11328 Return a service that adds the @code{xfce} package to the system profile,
11329 and extends polkit with the ability for @code{thunar} to manipulate the
11330 file system as root from within a user session, after the user has
11331 authenticated with the administrator's password.
11334 Because the GNOME and XFCE desktop services pull in so many packages,
11335 the default @code{%desktop-services} variable doesn't include either of
11336 them by default. To add GNOME or XFCE, just @code{cons} them onto
11337 @code{%desktop-services} in the @code{services} field of your
11338 @code{operating-system}:
11341 (use-modules (gnu))
11342 (use-service-modules desktop)
11345 ;; cons* adds items to the list given as its last argument.
11346 (services (cons* (gnome-desktop-service)
11347 (xfce-desktop-service)
11348 %desktop-services))
11352 These desktop environments will then be available as options in the
11353 graphical login window.
11355 The actual service definitions included in @code{%desktop-services} and
11356 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11357 are described below.
11359 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11360 Return a service that runs the ``system bus'', using @var{dbus}, with
11361 support for @var{services}.
11363 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11364 facility. Its system bus is used to allow system services to communicate
11365 and to be notified of system-wide events.
11367 @var{services} must be a list of packages that provide an
11368 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11369 and policy files. For example, to allow avahi-daemon to use the system bus,
11370 @var{services} must be equal to @code{(list avahi)}.
11373 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11374 Return a service that runs the @code{elogind} login and
11375 seat management daemon. @uref{https://github.com/andywingo/elogind,
11376 Elogind} exposes a D-Bus interface that can be used to know which users
11377 are logged in, know what kind of sessions they have open, suspend the
11378 system, inhibit system suspend, reboot the system, and other tasks.
11380 Elogind handles most system-level power events for a computer, for
11381 example suspending the system when a lid is closed, or shutting it down
11382 when the power button is pressed.
11384 The @var{config} keyword argument specifies the configuration for
11385 elogind, and should be the result of an @code{(elogind-configuration
11386 (@var{parameter} @var{value})...)} invocation. Available parameters and
11387 their default values are:
11390 @item kill-user-processes?
11392 @item kill-only-users
11394 @item kill-exclude-users
11396 @item inhibit-delay-max-seconds
11398 @item handle-power-key
11400 @item handle-suspend-key
11402 @item handle-hibernate-key
11404 @item handle-lid-switch
11406 @item handle-lid-switch-docked
11408 @item power-key-ignore-inhibited?
11410 @item suspend-key-ignore-inhibited?
11412 @item hibernate-key-ignore-inhibited?
11414 @item lid-switch-ignore-inhibited?
11416 @item holdoff-timeout-seconds
11420 @item idle-action-seconds
11422 @item runtime-directory-size-percent
11424 @item runtime-directory-size
11428 @item suspend-state
11429 @code{("mem" "standby" "freeze")}
11432 @item hibernate-state
11434 @item hibernate-mode
11435 @code{("platform" "shutdown")}
11436 @item hybrid-sleep-state
11438 @item hybrid-sleep-mode
11439 @code{("suspend" "platform" "shutdown")}
11443 @deffn {Scheme Procedure} polkit-service @
11444 [#:polkit @var{polkit}]
11445 Return a service that runs the
11446 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11447 management service}, which allows system administrators to grant access to
11448 privileged operations in a structured way. By querying the Polkit service, a
11449 privileged system component can know when it should grant additional
11450 capabilities to ordinary users. For example, an ordinary user can be granted
11451 the capability to suspend the system if the user is logged in locally.
11454 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11455 [#:watts-up-pro? #f] @
11456 [#:poll-batteries? #t] @
11457 [#:ignore-lid? #f] @
11458 [#:use-percentage-for-policy? #f] @
11459 [#:percentage-low 10] @
11460 [#:percentage-critical 3] @
11461 [#:percentage-action 2] @
11462 [#:time-low 1200] @
11463 [#:time-critical 300] @
11464 [#:time-action 120] @
11465 [#:critical-power-action 'hybrid-sleep]
11466 Return a service that runs @uref{http://upower.freedesktop.org/,
11467 @command{upowerd}}, a system-wide monitor for power consumption and battery
11468 levels, with the given configuration settings. It implements the
11469 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11473 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11474 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11475 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11476 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11477 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11480 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11481 Return a service that runs @command{colord}, a system service with a D-Bus
11482 interface to manage the color profiles of input and output devices such as
11483 screens and scanners. It is notably used by the GNOME Color Manager graphical
11484 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11485 site} for more information.
11488 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11489 Return a configuration allowing an application to access GeoClue
11490 location data. @var{name} is the Desktop ID of the application, without
11491 the @code{.desktop} part. If @var{allowed?} is true, the application
11492 will have access to location information by default. The boolean
11493 @var{system?} value indicates whether an application is a system component
11494 or not. Finally @var{users} is a list of UIDs of all users for which
11495 this application is allowed location info access. An empty users list
11496 means that all users are allowed.
11499 @defvr {Scheme Variable} %standard-geoclue-applications
11500 The standard list of well-known GeoClue application configurations,
11501 granting authority to the GNOME date-and-time utility to ask for the
11502 current location in order to set the time zone, and allowing the
11503 IceCat and Epiphany web browsers to request location information.
11504 IceCat and Epiphany both query the user before allowing a web page to
11505 know the user's location.
11508 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11509 [#:whitelist '()] @
11510 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11511 [#:submit-data? #f]
11512 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11513 [#:submission-nick "geoclue"] @
11514 [#:applications %standard-geoclue-applications]
11515 Return a service that runs the GeoClue location service. This service
11516 provides a D-Bus interface to allow applications to request access to a
11517 user's physical location, and optionally to add information to online
11518 location databases. See
11519 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11520 web site} for more information.
11523 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11524 Return a service that runs the @command{bluetoothd} daemon, which manages
11525 all the Bluetooth devices and provides a number of D-Bus interfaces.
11527 Users need to be in the @code{lp} group to access the D-Bus service.
11530 @node Database Services
11531 @subsubsection Database Services
11535 The @code{(gnu services databases)} module provides the following services.
11537 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11538 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11539 [#:port 5432] [#:locale ``en_US.utf8'']
11540 Return a service that runs @var{postgresql}, the PostgreSQL database
11543 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11544 creates a database cluster with @var{locale} as the default
11545 locale, stored in @var{data-directory}. It then listens on @var{port}.
11548 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11549 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11552 The optional @var{config} argument specifies the configuration for
11553 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11556 @deftp {Data Type} mysql-configuration
11557 Data type representing the configuration of @var{mysql-service}.
11560 @item @code{mysql} (default: @var{mariadb})
11561 Package object of the MySQL database server, can be either @var{mariadb}
11564 For MySQL, a temporary root password will be displayed at activation time.
11565 For MariaDB, the root password is empty.
11567 @item @code{port} (default: @code{3306})
11568 TCP port on which the database server listens for incoming connections.
11572 @defvr {Scheme Variable} redis-service-type
11573 This is the service type for the @uref{https://redis.io/, Redis}
11574 key/value store, whose value is a @code{redis-configuration} object.
11577 @deftp {Data Type} redis-configuration
11578 Data type representing the configuration of redis.
11581 @item @code{redis} (default: @code{redis})
11582 The Redis package to use.
11584 @item @code{bind} (default: @code{"127.0.0.1"})
11585 Network interface on which to listen.
11587 @item @code{port} (default: @code{6379})
11588 Port on which to accept connections on, a value of 0 will disable
11589 listening on a TCP socket.
11591 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11592 Directory in which to store the database and related files.
11596 @node Mail Services
11597 @subsubsection Mail Services
11601 The @code{(gnu services mail)} module provides Guix service definitions
11602 for email services: IMAP, POP3, and LMTP servers, as well as mail
11603 transport agents (MTAs). Lots of acronyms! These services are detailed
11604 in the subsections below.
11606 @subsubheading Dovecot Service
11608 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11609 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11612 By default, Dovecot does not need much configuration; the default
11613 configuration object created by @code{(dovecot-configuration)} will
11614 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11615 certificate will be generated for TLS-protected connections, though
11616 Dovecot will also listen on cleartext ports by default. There are a
11617 number of options, though, which mail administrators might need to change,
11618 and as is the case with other services, Guix allows the system
11619 administrator to specify these parameters via a uniform Scheme interface.
11621 For example, to specify that mail is located at @code{maildir~/.mail},
11622 one would instantiate the Dovecot service like this:
11625 (dovecot-service #:config
11626 (dovecot-configuration
11627 (mail-location "maildir:~/.mail")))
11630 The available configuration parameters follow. Each parameter
11631 definition is preceded by its type; for example, @samp{string-list foo}
11632 indicates that the @code{foo} parameter should be specified as a list of
11633 strings. There is also a way to specify the configuration as a string,
11634 if you have an old @code{dovecot.conf} file that you want to port over
11635 from some other system; see the end for more details.
11637 @c The following documentation was initially generated by
11638 @c (generate-documentation) in (gnu services mail). Manually maintained
11639 @c documentation is better, so we shouldn't hesitate to edit below as
11640 @c needed. However if the change you want to make to this documentation
11641 @c can be done in an automated way, it's probably easier to change
11642 @c (generate-documentation) than to make it below and have to deal with
11643 @c the churn as dovecot updates.
11645 Available @code{dovecot-configuration} fields are:
11647 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11648 The dovecot package.
11651 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11652 A list of IPs or hosts where to listen for connections. @samp{*}
11653 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11654 interfaces. If you want to specify non-default ports or anything more
11655 complex, customize the address and port fields of the
11656 @samp{inet-listener} of the specific services you are interested in.
11659 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11660 List of protocols we want to serve. Available protocols include
11661 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11663 Available @code{protocol-configuration} fields are:
11665 @deftypevr {@code{protocol-configuration} parameter} string name
11666 The name of the protocol.
11669 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11670 UNIX socket path to the master authentication server to find users.
11671 This is used by imap (for shared users) and lda.
11672 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11675 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11676 Space separated list of plugins to load.
11679 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11680 Maximum number of IMAP connections allowed for a user from each IP
11681 address. NOTE: The username is compared case-sensitively.
11682 Defaults to @samp{10}.
11687 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11688 List of services to enable. Available services include @samp{imap},
11689 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11692 Available @code{service-configuration} fields are:
11694 @deftypevr {@code{service-configuration} parameter} string kind
11695 The service kind. Valid values include @code{director},
11696 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11697 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11698 @code{tcpwrap}, @code{quota-warning}, or anything else.
11701 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11702 Listeners for the service. A listener is either a
11703 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11704 an @code{inet-listener-configuration}.
11705 Defaults to @samp{()}.
11707 Available @code{unix-listener-configuration} fields are:
11709 @deftypevr {@code{unix-listener-configuration} parameter} string path
11710 Path to the file, relative to @code{base-dir} field. This is also used as
11714 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11715 The access mode for the socket.
11716 Defaults to @samp{"0600"}.
11719 @deftypevr {@code{unix-listener-configuration} parameter} string user
11720 The user to own the socket.
11721 Defaults to @samp{""}.
11724 @deftypevr {@code{unix-listener-configuration} parameter} string group
11725 The group to own the socket.
11726 Defaults to @samp{""}.
11730 Available @code{fifo-listener-configuration} fields are:
11732 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11733 Path to the file, relative to @code{base-dir} field. This is also used as
11737 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11738 The access mode for the socket.
11739 Defaults to @samp{"0600"}.
11742 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11743 The user to own the socket.
11744 Defaults to @samp{""}.
11747 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11748 The group to own the socket.
11749 Defaults to @samp{""}.
11753 Available @code{inet-listener-configuration} fields are:
11755 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11756 The protocol to listen for.
11759 @deftypevr {@code{inet-listener-configuration} parameter} string address
11760 The address on which to listen, or empty for all addresses.
11761 Defaults to @samp{""}.
11764 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11765 The port on which to listen.
11768 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11769 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11771 Defaults to @samp{#t}.
11776 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11777 Number of connections to handle before starting a new process.
11778 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11779 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11780 Defaults to @samp{1}.
11783 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11784 Number of processes to always keep waiting for more connections.
11785 Defaults to @samp{0}.
11788 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11789 If you set @samp{service-count 0}, you probably need to grow
11791 Defaults to @samp{256000000}.
11796 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11797 Dict configuration, as created by the @code{dict-configuration}
11800 Available @code{dict-configuration} fields are:
11802 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11803 A list of key-value pairs that this dict should hold.
11804 Defaults to @samp{()}.
11809 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11810 A list of passdb configurations, each one created by the
11811 @code{passdb-configuration} constructor.
11813 Available @code{passdb-configuration} fields are:
11815 @deftypevr {@code{passdb-configuration} parameter} string driver
11816 The driver that the passdb should use. Valid values include
11817 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11819 Defaults to @samp{"pam"}.
11822 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11823 Space separated list of arguments to the passdb driver.
11824 Defaults to @samp{""}.
11829 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11830 List of userdb configurations, each one created by the
11831 @code{userdb-configuration} constructor.
11833 Available @code{userdb-configuration} fields are:
11835 @deftypevr {@code{userdb-configuration} parameter} string driver
11836 The driver that the userdb should use. Valid values include
11837 @samp{passwd} and @samp{static}.
11838 Defaults to @samp{"passwd"}.
11841 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11842 Space separated list of arguments to the userdb driver.
11843 Defaults to @samp{""}.
11846 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11847 Override fields from passwd.
11848 Defaults to @samp{()}.
11853 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11854 Plug-in configuration, created by the @code{plugin-configuration}
11858 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11859 List of namespaces. Each item in the list is created by the
11860 @code{namespace-configuration} constructor.
11862 Available @code{namespace-configuration} fields are:
11864 @deftypevr {@code{namespace-configuration} parameter} string name
11865 Name for this namespace.
11868 @deftypevr {@code{namespace-configuration} parameter} string type
11869 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11870 Defaults to @samp{"private"}.
11873 @deftypevr {@code{namespace-configuration} parameter} string separator
11874 Hierarchy separator to use. You should use the same separator for
11875 all namespaces or some clients get confused. @samp{/} is usually a good
11876 one. The default however depends on the underlying mail storage
11878 Defaults to @samp{""}.
11881 @deftypevr {@code{namespace-configuration} parameter} string prefix
11882 Prefix required to access this namespace. This needs to be
11883 different for all namespaces. For example @samp{Public/}.
11884 Defaults to @samp{""}.
11887 @deftypevr {@code{namespace-configuration} parameter} string location
11888 Physical location of the mailbox. This is in the same format as
11889 mail_location, which is also the default for it.
11890 Defaults to @samp{""}.
11893 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11894 There can be only one INBOX, and this setting defines which
11896 Defaults to @samp{#f}.
11899 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11900 If namespace is hidden, it's not advertised to clients via NAMESPACE
11901 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11902 useful when converting from another server with different namespaces
11903 which you want to deprecate but still keep working. For example you can
11904 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11906 Defaults to @samp{#f}.
11909 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11910 Show the mailboxes under this namespace with the LIST command. This
11911 makes the namespace visible for clients that do not support the NAMESPACE
11912 extension. The special @code{children} value lists child mailboxes, but
11913 hides the namespace prefix.
11914 Defaults to @samp{#t}.
11917 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11918 Namespace handles its own subscriptions. If set to @code{#f}, the
11919 parent namespace handles them. The empty prefix should always have this
11921 Defaults to @samp{#t}.
11924 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11925 List of predefined mailboxes in this namespace.
11926 Defaults to @samp{()}.
11928 Available @code{mailbox-configuration} fields are:
11930 @deftypevr {@code{mailbox-configuration} parameter} string name
11931 Name for this mailbox.
11934 @deftypevr {@code{mailbox-configuration} parameter} string auto
11935 @samp{create} will automatically create this mailbox.
11936 @samp{subscribe} will both create and subscribe to the mailbox.
11937 Defaults to @samp{"no"}.
11940 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11941 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11942 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11943 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11944 Defaults to @samp{()}.
11951 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11952 Base directory where to store runtime data.
11953 Defaults to @samp{"/var/run/dovecot/"}.
11956 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11957 Greeting message for clients.
11958 Defaults to @samp{"Dovecot ready."}.
11961 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11962 List of trusted network ranges. Connections from these IPs are
11963 allowed to override their IP addresses and ports (for logging and for
11964 authentication checks). @samp{disable-plaintext-auth} is also ignored
11965 for these networks. Typically you would specify your IMAP proxy servers
11967 Defaults to @samp{()}.
11970 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11971 List of login access check sockets (e.g. tcpwrap).
11972 Defaults to @samp{()}.
11975 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11976 Show more verbose process titles (in ps). Currently shows user name
11977 and IP address. Useful for seeing who is actually using the IMAP
11978 processes (e.g. shared mailboxes or if the same uid is used for multiple
11980 Defaults to @samp{#f}.
11983 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11984 Should all processes be killed when Dovecot master process shuts down.
11985 Setting this to @code{#f} means that Dovecot can be upgraded without
11986 forcing existing client connections to close (although that could also
11987 be a problem if the upgrade is e.g. due to a security fix).
11988 Defaults to @samp{#t}.
11991 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11992 If non-zero, run mail commands via this many connections to doveadm
11993 server, instead of running them directly in the same process.
11994 Defaults to @samp{0}.
11997 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11998 UNIX socket or host:port used for connecting to doveadm server.
11999 Defaults to @samp{"doveadm-server"}.
12002 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12003 List of environment variables that are preserved on Dovecot startup
12004 and passed down to all of its child processes. You can also give
12005 key=value pairs to always set specific settings.
12008 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12009 Disable LOGIN command and all other plaintext authentications unless
12010 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12011 matches the local IP (i.e. you're connecting from the same computer),
12012 the connection is considered secure and plaintext authentication is
12013 allowed. See also ssl=required setting.
12014 Defaults to @samp{#t}.
12017 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12018 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12019 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12020 for caching to be used.
12021 Defaults to @samp{0}.
12024 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12025 Time to live for cached data. After TTL expires the cached record
12026 is no longer used, *except* if the main database lookup returns internal
12027 failure. We also try to handle password changes automatically: If
12028 user's previous authentication was successful, but this one wasn't, the
12029 cache isn't used. For now this works only with plaintext
12031 Defaults to @samp{"1 hour"}.
12034 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12035 TTL for negative hits (user not found, password mismatch).
12036 0 disables caching them completely.
12037 Defaults to @samp{"1 hour"}.
12040 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12041 List of realms for SASL authentication mechanisms that need them.
12042 You can leave it empty if you don't want to support multiple realms.
12043 Many clients simply use the first one listed here, so keep the default
12045 Defaults to @samp{()}.
12048 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12049 Default realm/domain to use if none was specified. This is used for
12050 both SASL realms and appending @@domain to username in plaintext
12052 Defaults to @samp{""}.
12055 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12056 List of allowed characters in username. If the user-given username
12057 contains a character not listed in here, the login automatically fails.
12058 This is just an extra check to make sure user can't exploit any
12059 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12060 you want to allow all characters, set this value to empty.
12061 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12064 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12065 Username character translations before it's looked up from
12066 databases. The value contains series of from -> to characters. For
12067 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12068 translated to @samp{@@}.
12069 Defaults to @samp{""}.
12072 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12073 Username formatting before it's looked up from databases. You can
12074 use the standard variables here, e.g. %Lu would lowercase the username,
12075 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12076 change the @samp{@@} into @samp{-AT-}. This translation is done after
12077 @samp{auth-username-translation} changes.
12078 Defaults to @samp{"%Lu"}.
12081 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12082 If you want to allow master users to log in by specifying the master
12083 username within the normal username string (i.e. not using SASL
12084 mechanism's support for it), you can specify the separator character
12085 here. The format is then <username><separator><master username>.
12086 UW-IMAP uses @samp{*} as the separator, so that could be a good
12088 Defaults to @samp{""}.
12091 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12092 Username to use for users logging in with ANONYMOUS SASL
12094 Defaults to @samp{"anonymous"}.
12097 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12098 Maximum number of dovecot-auth worker processes. They're used to
12099 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12100 They're automatically created and destroyed as needed.
12101 Defaults to @samp{30}.
12104 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12105 Host name to use in GSSAPI principal names. The default is to use
12106 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12107 allow all keytab entries.
12108 Defaults to @samp{""}.
12111 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12112 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12113 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12114 need to change the auth service to run as root to be able to read this
12116 Defaults to @samp{""}.
12119 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12120 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12121 and @samp{ntlm-auth} helper.
12122 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12123 Defaults to @samp{#f}.
12126 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12127 Path for Samba's @samp{ntlm-auth} helper binary.
12128 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12131 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12132 Time to delay before replying to failed authentications.
12133 Defaults to @samp{"2 secs"}.
12136 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12137 Require a valid SSL client certificate or the authentication
12139 Defaults to @samp{#f}.
12142 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12143 Take the username from client's SSL certificate, using
12144 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12146 Defaults to @samp{#f}.
12149 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12150 List of wanted authentication mechanisms. Supported mechanisms are:
12151 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12152 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12153 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12154 @samp{disable-plaintext-auth} setting.
12157 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12158 List of IPs or hostnames to all director servers, including ourself.
12159 Ports can be specified as ip:port. The default port is the same as what
12160 director service's @samp{inet-listener} is using.
12161 Defaults to @samp{()}.
12164 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12165 List of IPs or hostnames to all backend mail servers. Ranges are
12166 allowed too, like 10.0.0.10-10.0.0.30.
12167 Defaults to @samp{()}.
12170 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12171 How long to redirect users to a specific server after it no longer
12172 has any connections.
12173 Defaults to @samp{"15 min"}.
12176 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12177 TCP/IP port that accepts doveadm connections (instead of director
12178 connections) If you enable this, you'll also need to add
12179 @samp{inet-listener} for the port.
12180 Defaults to @samp{0}.
12183 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12184 How the username is translated before being hashed. Useful values
12185 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12186 are shared within domain.
12187 Defaults to @samp{"%Lu"}.
12190 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12191 Log file to use for error messages. @samp{syslog} logs to syslog,
12192 @samp{/dev/stderr} logs to stderr.
12193 Defaults to @samp{"syslog"}.
12196 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12197 Log file to use for informational messages. Defaults to
12199 Defaults to @samp{""}.
12202 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12203 Log file to use for debug messages. Defaults to
12204 @samp{info-log-path}.
12205 Defaults to @samp{""}.
12208 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12209 Syslog facility to use if you're logging to syslog. Usually if you
12210 don't want to use @samp{mail}, you'll use local0..local7. Also other
12211 standard facilities are supported.
12212 Defaults to @samp{"mail"}.
12215 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12216 Log unsuccessful authentication attempts and the reasons why they
12218 Defaults to @samp{#f}.
12221 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12222 In case of password mismatches, log the attempted password. Valid
12223 values are no, plain and sha1. sha1 can be useful for detecting brute
12224 force password attempts vs. user simply trying the same password over
12225 and over again. You can also truncate the value to n chars by appending
12226 ":n" (e.g. sha1:6).
12227 Defaults to @samp{#f}.
12230 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12231 Even more verbose logging for debugging purposes. Shows for example
12233 Defaults to @samp{#f}.
12236 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12237 In case of password mismatches, log the passwords and used scheme so
12238 the problem can be debugged. Enabling this also enables
12240 Defaults to @samp{#f}.
12243 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12244 Enable mail process debugging. This can help you figure out why
12245 Dovecot isn't finding your mails.
12246 Defaults to @samp{#f}.
12249 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12250 Show protocol level SSL errors.
12251 Defaults to @samp{#f}.
12254 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12255 Prefix for each line written to log file. % codes are in
12256 strftime(3) format.
12257 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12260 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12261 List of elements we want to log. The elements which have a
12262 non-empty variable value are joined together to form a comma-separated
12266 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12267 Login log format. %s contains @samp{login-log-format-elements}
12268 string, %$ contains the data we want to log.
12269 Defaults to @samp{"%$: %s"}.
12272 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12273 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12274 of possible variables you can use.
12275 Defaults to @samp{"\"%s(%u): \""}.
12278 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12279 Format to use for logging mail deliveries. You can use variables:
12282 Delivery status message (e.g. @samp{saved to INBOX})
12294 Defaults to @samp{"msgid=%m: %$"}.
12297 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12298 Location for users' mailboxes. The default is empty, which means
12299 that Dovecot tries to find the mailboxes automatically. This won't work
12300 if the user doesn't yet have any mail, so you should explicitly tell
12301 Dovecot the full location.
12303 If you're using mbox, giving a path to the INBOX
12304 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12305 where the other mailboxes are kept. This is called the "root mail
12306 directory", and it must be the first path given in the
12307 @samp{mail-location} setting.
12309 There are a few special variables you can use, eg.:
12315 user part in user@@domain, same as %u if there's no domain
12317 domain part in user@@domain, empty if there's no domain
12322 See doc/wiki/Variables.txt for full list. Some examples:
12324 @item maildir:~/Maildir
12325 @item mbox:~/mail:INBOX=/var/mail/%u
12326 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12328 Defaults to @samp{""}.
12331 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12332 System user and group used to access mails. If you use multiple,
12333 userdb can override these by returning uid or gid fields. You can use
12334 either numbers or names. <doc/wiki/UserIds.txt>.
12335 Defaults to @samp{""}.
12338 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12340 Defaults to @samp{""}.
12343 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12344 Group to enable temporarily for privileged operations. Currently
12345 this is used only with INBOX when either its initial creation or
12346 dotlocking fails. Typically this is set to "mail" to give access to
12348 Defaults to @samp{""}.
12351 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12352 Grant access to these supplementary groups for mail processes.
12353 Typically these are used to set up access to shared mailboxes. Note
12354 that it may be dangerous to set these if users can create
12355 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12356 could allow a user to delete others' mailboxes, or ln -s
12357 /secret/shared/box ~/mail/mybox would allow reading it).
12358 Defaults to @samp{""}.
12361 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12362 Allow full file system access to clients. There's no access checks
12363 other than what the operating system does for the active UID/GID. It
12364 works with both maildir and mboxes, allowing you to prefix mailboxes
12365 names with e.g. /path/ or ~user/.
12366 Defaults to @samp{#f}.
12369 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12370 Don't use mmap() at all. This is required if you store indexes to
12371 shared file systems (NFS or clustered file system).
12372 Defaults to @samp{#f}.
12375 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12376 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12377 supports @samp{O_EXCL} since version 3, so this should be safe to use
12378 nowadays by default.
12379 Defaults to @samp{#t}.
12382 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12383 When to use fsync() or fdatasync() calls:
12386 Whenever necessary to avoid losing important data
12388 Useful with e.g. NFS when write()s are delayed
12390 Never use it (best performance, but crashes can lose data).
12392 Defaults to @samp{"optimized"}.
12395 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12396 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12397 NFS caches whenever needed. If you're using only a single mail server
12399 Defaults to @samp{#f}.
12402 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12403 Mail index files also exist in NFS. Setting this to yes requires
12404 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12405 Defaults to @samp{#f}.
12408 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12409 Locking method for index files. Alternatives are fcntl, flock and
12410 dotlock. Dotlocking uses some tricks which may create more disk I/O
12411 than other locking methods. NFS users: flock doesn't work, remember to
12412 change @samp{mmap-disable}.
12413 Defaults to @samp{"fcntl"}.
12416 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12417 Directory in which LDA/LMTP temporarily stores incoming mails >128
12419 Defaults to @samp{"/tmp"}.
12422 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12423 Valid UID range for users. This is mostly to make sure that users can't
12424 log in as daemons or other system users. Note that denying root logins is
12425 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12427 Defaults to @samp{500}.
12430 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12432 Defaults to @samp{0}.
12435 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12436 Valid GID range for users. Users having non-valid GID as primary group ID
12437 aren't allowed to log in. If user belongs to supplementary groups with
12438 non-valid GIDs, those groups are not set.
12439 Defaults to @samp{1}.
12442 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12444 Defaults to @samp{0}.
12447 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12448 Maximum allowed length for mail keyword name. It's only forced when
12449 trying to create new keywords.
12450 Defaults to @samp{50}.
12453 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12454 List of directories under which chrooting is allowed for mail
12455 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12456 too). This setting doesn't affect @samp{login-chroot}
12457 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12458 "/./" in home dirs are ignored. WARNING: Never add directories here
12459 which local users can modify, that may lead to root exploit. Usually
12460 this should be done only if you don't allow shell access for users.
12461 <doc/wiki/Chrooting.txt>.
12462 Defaults to @samp{()}.
12465 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12466 Default chroot directory for mail processes. This can be overridden
12467 for specific users in user database by giving /./ in user's home
12468 directory (e.g. /home/./user chroots into /home). Note that usually
12469 there is no real need to do chrooting, Dovecot doesn't allow users to
12470 access files outside their mail directory anyway. If your home
12471 directories are prefixed with the chroot directory, append "/." to
12472 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12473 Defaults to @samp{""}.
12476 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12477 UNIX socket path to master authentication server to find users.
12478 This is used by imap (for shared users) and lda.
12479 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12482 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12483 Directory where to look up mail plugins.
12484 Defaults to @samp{"/usr/lib/dovecot"}.
12487 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12488 List of plugins to load for all services. Plugins specific to IMAP,
12489 LDA, etc. are added to this list in their own .conf files.
12490 Defaults to @samp{()}.
12493 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12494 The minimum number of mails in a mailbox before updates are done to
12495 cache file. This allows optimizing Dovecot's behavior to do less disk
12496 writes at the cost of more disk reads.
12497 Defaults to @samp{0}.
12500 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12501 When IDLE command is running, mailbox is checked once in a while to
12502 see if there are any new mails or other changes. This setting defines
12503 the minimum time to wait between those checks. Dovecot can also use
12504 dnotify, inotify and kqueue to find out immediately when changes
12506 Defaults to @samp{"30 secs"}.
12509 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12510 Save mails with CR+LF instead of plain LF. This makes sending those
12511 mails take less CPU, especially with sendfile() syscall with Linux and
12512 FreeBSD. But it also creates a bit more disk I/O which may just make it
12513 slower. Also note that if other software reads the mboxes/maildirs,
12514 they may handle the extra CRs wrong and cause problems.
12515 Defaults to @samp{#f}.
12518 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12519 By default LIST command returns all entries in maildir beginning
12520 with a dot. Enabling this option makes Dovecot return only entries
12521 which are directories. This is done by stat()ing each entry, so it
12522 causes more disk I/O.
12523 (For systems setting struct @samp{dirent->d_type} this check is free
12524 and it's done always regardless of this setting).
12525 Defaults to @samp{#f}.
12528 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12529 When copying a message, do it with hard links whenever possible.
12530 This makes the performance much better, and it's unlikely to have any
12532 Defaults to @samp{#t}.
12535 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12536 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12537 directory only when its mtime changes unexpectedly or when we can't find
12538 the mail otherwise.
12539 Defaults to @samp{#f}.
12542 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12543 Which locking methods to use for locking mbox. There are four
12548 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12549 solution. If you want to use /var/mail/ like directory, the users will
12550 need write access to that directory.
12552 Same as dotlock, but if it fails because of permissions or because there
12553 isn't enough disk space, just skip it.
12555 Use this if possible. Works with NFS too if lockd is used.
12557 May not exist in all systems. Doesn't work with NFS.
12559 May not exist in all systems. Doesn't work with NFS.
12562 You can use multiple locking methods; if you do the order they're declared
12563 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12564 locking methods as well. Some operating systems don't allow using some of
12565 them simultaneously.
12568 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12572 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12573 Maximum time to wait for lock (all of them) before aborting.
12574 Defaults to @samp{"5 mins"}.
12577 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12578 If dotlock exists but the mailbox isn't modified in any way,
12579 override the lock file after this much time.
12580 Defaults to @samp{"2 mins"}.
12583 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12584 When mbox changes unexpectedly we have to fully read it to find out
12585 what changed. If the mbox is large this can take a long time. Since
12586 the change is usually just a newly appended mail, it'd be faster to
12587 simply read the new mails. If this setting is enabled, Dovecot does
12588 this but still safely fallbacks to re-reading the whole mbox file
12589 whenever something in mbox isn't how it's expected to be. The only real
12590 downside to this setting is that if some other MUA changes message
12591 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12592 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12593 Defaults to @samp{#t}.
12596 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12597 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12598 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12599 @samp{mbox-dirty-syncs} is ignored.
12600 Defaults to @samp{#f}.
12603 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12604 Delay writing mbox headers until doing a full write sync (EXPUNGE
12605 and CHECK commands and when closing the mailbox). This is especially
12606 useful for POP3 where clients often delete all mails. The downside is
12607 that our changes aren't immediately visible to other MUAs.
12608 Defaults to @samp{#t}.
12611 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12612 If mbox size is smaller than this (e.g. 100k), don't write index
12613 files. If an index file already exists it's still read, just not
12615 Defaults to @samp{0}.
12618 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12619 Maximum dbox file size until it's rotated.
12620 Defaults to @samp{2000000}.
12623 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12624 Maximum dbox file age until it's rotated. Typically in days. Day
12625 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12627 Defaults to @samp{"1d"}.
12630 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12631 When creating new mdbox files, immediately preallocate their size to
12632 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12633 with some file systems (ext4, xfs).
12634 Defaults to @samp{#f}.
12637 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12638 sdbox and mdbox support saving mail attachments to external files,
12639 which also allows single instance storage for them. Other backends
12640 don't support this for now.
12642 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12644 Directory root where to store mail attachments. Disabled, if empty.
12645 Defaults to @samp{""}.
12648 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12649 Attachments smaller than this aren't saved externally. It's also
12650 possible to write a plugin to disable saving specific attachments
12652 Defaults to @samp{128000}.
12655 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12656 File system backend to use for saving attachments:
12659 No SiS done by Dovecot (but this might help FS's own deduplication)
12661 SiS with immediate byte-by-byte comparison during saving
12662 @item sis-queue posix
12663 SiS with delayed comparison and deduplication.
12665 Defaults to @samp{"sis posix"}.
12668 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12669 Hash format to use in attachment filenames. You can add any text and
12670 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12671 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12672 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12673 Defaults to @samp{"%@{sha1@}"}.
12676 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12678 Defaults to @samp{100}.
12681 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12683 Defaults to @samp{1000}.
12686 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12687 Default VSZ (virtual memory size) limit for service processes.
12688 This is mainly intended to catch and kill processes that leak memory
12689 before they eat up everything.
12690 Defaults to @samp{256000000}.
12693 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12694 Login user is internally used by login processes. This is the most
12695 untrusted user in Dovecot system. It shouldn't have access to anything
12697 Defaults to @samp{"dovenull"}.
12700 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12701 Internal user is used by unprivileged processes. It should be
12702 separate from login user, so that login processes can't disturb other
12704 Defaults to @samp{"dovecot"}.
12707 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12708 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12709 Defaults to @samp{"required"}.
12712 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12713 PEM encoded X.509 SSL/TLS certificate (public key).
12714 Defaults to @samp{"</etc/dovecot/default.pem"}.
12717 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12718 PEM encoded SSL/TLS private key. The key is opened before
12719 dropping root privileges, so keep the key file unreadable by anyone but
12721 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12724 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12725 If key file is password protected, give the password here.
12726 Alternatively give it when starting dovecot with -p parameter. Since
12727 this file is often world-readable, you may want to place this setting
12728 instead to a different.
12729 Defaults to @samp{""}.
12732 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12733 PEM encoded trusted certificate authority. Set this only if you
12734 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12735 contain the CA certificate(s) followed by the matching
12736 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12737 Defaults to @samp{""}.
12740 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12741 Require that CRL check succeeds for client certificates.
12742 Defaults to @samp{#t}.
12745 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12746 Request client to send a certificate. If you also want to require
12747 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12748 Defaults to @samp{#f}.
12751 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12752 Which field from certificate to use for username. commonName and
12753 x500UniqueIdentifier are the usual choices. You'll also need to set
12754 @samp{auth-ssl-username-from-cert? #t}.
12755 Defaults to @samp{"commonName"}.
12758 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12759 How often to regenerate the SSL parameters file. Generation is
12760 quite CPU intensive operation. The value is in hours, 0 disables
12761 regeneration entirely.
12762 Defaults to @samp{168}.
12765 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12766 SSL protocols to use.
12767 Defaults to @samp{"!SSLv2"}.
12770 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12771 SSL ciphers to use.
12772 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12775 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12776 SSL crypto device to use, for valid values run "openssl engine".
12777 Defaults to @samp{""}.
12780 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12781 Address to use when sending rejection mails.
12782 %d expands to recipient domain.
12783 Defaults to @samp{"postmaster@@%d"}.
12786 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12787 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12788 and in LMTP replies. Default is the system's real hostname@@domain.
12789 Defaults to @samp{""}.
12792 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12793 If user is over quota, return with temporary failure instead of
12795 Defaults to @samp{#f}.
12798 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12799 Binary to use for sending mails.
12800 Defaults to @samp{"/usr/sbin/sendmail"}.
12803 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12804 If non-empty, send mails via this SMTP host[:port] instead of
12806 Defaults to @samp{""}.
12809 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12810 Subject: header to use for rejection mails. You can use the same
12811 variables as for @samp{rejection-reason} below.
12812 Defaults to @samp{"Rejected: %s"}.
12815 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12816 Human readable error message for rejection mails. You can use
12829 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12832 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12833 Delimiter character between local-part and detail in email
12835 Defaults to @samp{"+"}.
12838 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12839 Header where the original recipient address (SMTP's RCPT TO:
12840 address) is taken from if not available elsewhere. With dovecot-lda -a
12841 parameter overrides this. A commonly used header for this is
12843 Defaults to @samp{""}.
12846 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12847 Should saving a mail to a nonexistent mailbox automatically create
12849 Defaults to @samp{#f}.
12852 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12853 Should automatically created mailboxes be also automatically
12855 Defaults to @samp{#f}.
12858 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12859 Maximum IMAP command line length. Some clients generate very long
12860 command lines with huge mailboxes, so you may need to raise this if you
12861 get "Too long argument" or "IMAP command line too large" errors
12863 Defaults to @samp{64000}.
12866 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12867 IMAP logout format string:
12870 total number of bytes read from client
12872 total number of bytes sent to client.
12874 Defaults to @samp{"in=%i out=%o"}.
12877 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12878 Override the IMAP CAPABILITY response. If the value begins with '+',
12879 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12880 Defaults to @samp{""}.
12883 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12884 How long to wait between "OK Still here" notifications when client
12886 Defaults to @samp{"2 mins"}.
12889 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12890 ID field names and values to send to clients. Using * as the value
12891 makes Dovecot use the default value. The following fields have default
12892 values currently: name, version, os, os-version, support-url,
12894 Defaults to @samp{""}.
12897 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12898 ID fields sent by client to log. * means everything.
12899 Defaults to @samp{""}.
12902 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12903 Workarounds for various client bugs:
12906 @item delay-newmail
12907 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12908 CHECK commands. Some clients ignore them otherwise, for example OSX
12909 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12910 may show user "Message no longer in server" errors. Note that OE6
12911 still breaks even with this workaround if synchronization is set to
12914 @item tb-extra-mailbox-sep
12915 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12916 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12917 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12919 @item tb-lsub-flags
12920 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12921 This makes Thunderbird realize they aren't selectable and show them
12922 greyed out, instead of only later giving "not selectable" popup error.
12924 Defaults to @samp{()}.
12927 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12928 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12929 Defaults to @samp{""}.
12933 Whew! Lots of configuration options. The nice thing about it though is
12934 that GuixSD has a complete interface to Dovecot's configuration
12935 language. This allows not only a nice way to declare configurations,
12936 but also offers reflective capabilities as well: users can write code to
12937 inspect and transform configurations from within Scheme.
12939 However, it could be that you just want to get a @code{dovecot.conf} up
12940 and running. In that case, you can pass an
12941 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12942 @code{dovecot-service}. As its name indicates, an opaque configuration
12943 does not have easy reflective capabilities.
12945 Available @code{opaque-dovecot-configuration} fields are:
12947 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12948 The dovecot package.
12951 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12952 The contents of the @code{dovecot.conf}, as a string.
12955 For example, if your @code{dovecot.conf} is just the empty string, you
12956 could instantiate a dovecot service like this:
12959 (dovecot-service #:config
12960 (opaque-dovecot-configuration
12964 @subsubheading OpenSMTPD Service
12966 @deffn {Scheme Variable} opensmtpd-service-type
12967 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12968 service, whose value should be an @code{opensmtpd-configuration} object
12969 as in this example:
12972 (service opensmtpd-service-type
12973 (opensmtpd-configuration
12974 (config-file (local-file "./my-smtpd.conf"))))
12978 @deftp {Data Type} opensmtpd-configuration
12979 Data type representing the configuration of opensmtpd.
12982 @item @code{package} (default: @var{opensmtpd})
12983 Package object of the OpenSMTPD SMTP server.
12985 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12986 File-like object of the OpenSMTPD configuration file to use. By default
12987 it listens on the loopback network interface, and allows for mail from
12988 users and daemons on the local machine, as well as permitting email to
12989 remote servers. Run @command{man smtpd.conf} for more information.
12994 @subsubheading Exim Service
12996 @cindex mail transfer agent (MTA)
12997 @cindex MTA (mail transfer agent)
13000 @deffn {Scheme Variable} exim-service-type
13001 This is the type of the @uref{https://exim.org, Exim} mail transfer
13002 agent (MTA), whose value should be an @code{exim-configuration} object
13003 as in this example:
13006 (service exim-service-type
13007 (exim-configuration
13008 (config-file (local-file "./my-exim.conf"))))
13012 In order to use an @code{exim-service-type} service you must also have a
13013 @code{mail-aliases-service-type} service present in your
13014 @code{operating-system} (even if it has no aliases).
13016 @deftp {Data Type} exim-configuration
13017 Data type representing the configuration of exim.
13020 @item @code{package} (default: @var{exim})
13021 Package object of the Exim server.
13023 @item @code{config-file} (default: @code{#f})
13024 File-like object of the Exim configuration file to use. If its value is
13025 @code{#f} then use the default configuration file from the package
13026 provided in @code{package}. The resulting configuration file is loaded
13027 after setting the @code{exim_user} and @code{exim_group} configuration
13033 @subsubheading Mail Aliases Service
13035 @cindex email aliases
13036 @cindex aliases, for email addresses
13038 @deffn {Scheme Variable} mail-aliases-service-type
13039 This is the type of the service which provides @code{/etc/aliases},
13040 specifying how to deliver mail to users on this system.
13043 (service mail-aliases-service-type
13044 '(("postmaster" "bob")
13045 ("bob" "bob@@example.com" "bob@@example2.com")))
13049 The configuration for a @code{mail-aliases-service-type} service is an
13050 association list denoting how to deliver mail that comes to this
13051 system. Each entry is of the form @code{(alias addresses ...)}, with
13052 @code{alias} specifying the local alias and @code{addresses} specifying
13053 where to deliver this user's mail.
13055 The aliases aren't required to exist as users on the local system. In
13056 the above example, there doesn't need to be a @code{postmaster} entry in
13057 the @code{operating-system}'s @code{user-accounts} in order to deliver
13058 the @code{postmaster} mail to @code{bob} (which subsequently would
13059 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13061 @node Messaging Services
13062 @subsubsection Messaging Services
13067 The @code{(gnu services messaging)} module provides Guix service
13068 definitions for messaging services: currently only Prosody is supported.
13070 @subsubheading Prosody Service
13072 @deffn {Scheme Variable} prosody-service-type
13073 This is the type for the @uref{http://prosody.im, Prosody XMPP
13074 communication server}. Its value must be a @code{prosody-configuration}
13075 record as in this example:
13078 (service prosody-service-type
13079 (prosody-configuration
13080 (modules-enabled (cons "groups" %default-modules-enabled))
13083 (int-component-configuration
13084 (hostname "conference.example.net")
13086 (mod-muc (mod-muc-configuration)))))
13089 (virtualhost-configuration
13090 (domain "example.net"))))))
13093 See below for details about @code{prosody-configuration}.
13097 By default, Prosody does not need much configuration. Only one
13098 @code{virtualhosts} field is needed: it specifies the domain you wish
13101 Prosodyctl will help you generate X.509 certificates and keys:
13104 prosodyctl cert request example.net
13107 The available configuration parameters follow. Each parameter
13108 definition is preceded by its type; for example, @samp{string-list foo}
13109 indicates that the @code{foo} parameter should be specified as a list of
13110 strings. Types starting with @code{maybe-} denote parameters that won't
13111 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13113 There is also a way to specify the configuration as a string, if you
13114 have an old @code{prosody.cfg.lua} file that you want to port over from
13115 some other system; see the end for more details.
13117 @c The following documentation was initially generated by
13118 @c (generate-documentation) in (gnu services messaging). Manually maintained
13119 @c documentation is better, so we shouldn't hesitate to edit below as
13120 @c needed. However if the change you want to make to this documentation
13121 @c can be done in an automated way, it's probably easier to change
13122 @c (generate-documentation) than to make it below and have to deal with
13123 @c the churn as Prosody updates.
13125 Available @code{prosody-configuration} fields are:
13127 @deftypevr {@code{prosody-configuration} parameter} package prosody
13128 The Prosody package.
13131 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13132 Location of the Prosody data storage directory. See
13133 @url{http://prosody.im/doc/configure}.
13134 Defaults to @samp{"/var/lib/prosody"}.
13137 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13138 Additional plugin directories. They are searched in all the specified
13139 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13140 Defaults to @samp{()}.
13143 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13144 This is a list of accounts that are admins for the server. Note that you
13145 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13146 @url{http://prosody.im/doc/creating_accounts}.
13147 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13148 Defaults to @samp{()}.
13151 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13152 Enable use of libevent for better performance under high load. See
13153 @url{http://prosody.im/doc/libevent}.
13154 Defaults to @samp{#f}.
13157 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13158 This is the list of modules Prosody will load on startup. It looks for
13159 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13160 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13161 Defaults to @samp{%default-modules-enabled}.
13164 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13165 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13166 should you want to disable them then add them to this list.
13167 Defaults to @samp{()}.
13170 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13171 Path to a text file where the shared groups are defined. If this path is
13172 empty then @samp{mod_groups} does nothing. See
13173 @url{http://prosody.im/doc/modules/mod_groups}.
13174 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13177 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13178 Disable account creation by default, for security. See
13179 @url{http://prosody.im/doc/creating_accounts}.
13180 Defaults to @samp{#f}.
13183 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13184 These are the SSL/TLS-related settings. Most of them are disabled so to
13185 use Prosody's defaults. If you do not completely understand these options, do
13186 not add them to your config, it is easy to lower the security of your server
13187 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13189 Available @code{ssl-configuration} fields are:
13191 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13192 This determines what handshake to use.
13195 @deftypevr {@code{ssl-configuration} parameter} file-name key
13196 Path to your private key file, relative to @code{/etc/prosody}.
13197 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13200 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13201 Path to your certificate file, relative to @code{/etc/prosody}.
13202 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13205 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13206 Path to directory containing root certificates that you wish Prosody to
13207 trust when verifying the certificates of remote servers.
13208 Defaults to @samp{"/etc/ssl/certs"}.
13211 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13212 Path to a file containing root certificates that you wish Prosody to trust.
13213 Similar to @code{capath} but with all certificates concatenated together.
13216 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13217 A list of verification options (these mostly map to OpenSSL's
13218 @code{set_verify()} flags).
13221 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13222 A list of general options relating to SSL/TLS. These map to OpenSSL's
13223 @code{set_options()}. For a full list of options available in LuaSec, see the
13227 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13228 How long a chain of certificate authorities to check when looking for a
13229 trusted root certificate.
13232 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13233 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13234 clients, and in what order.
13237 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13238 A path to a file containing parameters for Diffie-Hellman key exchange. You
13239 can create such a file with:
13240 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13243 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13244 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13245 @samp{"secp384r1"}.
13248 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13249 A list of "extra" verification options.
13252 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13253 Password for encrypted private keys.
13258 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13259 Whether to force all client-to-server connections to be encrypted or not.
13260 See @url{http://prosody.im/doc/modules/mod_tls}.
13261 Defaults to @samp{#f}.
13264 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13265 Whether to force all server-to-server connections to be encrypted or not.
13266 See @url{http://prosody.im/doc/modules/mod_tls}.
13267 Defaults to @samp{#f}.
13270 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13271 Whether to require encryption and certificate authentication. This
13272 provides ideal security, but requires servers you communicate with to support
13273 encryption AND present valid, trusted certificates. See
13274 @url{http://prosody.im/doc/s2s#security}.
13275 Defaults to @samp{#f}.
13278 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13279 Many servers don't support encryption or have invalid or self-signed
13280 certificates. You can list domains here that will not be required to
13281 authenticate using certificates. They will be authenticated using DNS. See
13282 @url{http://prosody.im/doc/s2s#security}.
13283 Defaults to @samp{()}.
13286 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13287 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13288 valid certificates for some domains by specifying a list here. See
13289 @url{http://prosody.im/doc/s2s#security}.
13290 Defaults to @samp{()}.
13293 @deftypevr {@code{prosody-configuration} parameter} string authentication
13294 Select the authentication backend to use. The default provider stores
13295 passwords in plaintext and uses Prosody's configured data storage to store the
13296 authentication data. If you do not trust your server please see
13297 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13298 about using the hashed backend. See also
13299 @url{http://prosody.im/doc/authentication}
13300 Defaults to @samp{"internal_plain"}.
13303 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13304 Set logging options. Advanced logging configuration is not yet supported
13305 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13306 Defaults to @samp{"*syslog"}.
13309 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13310 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13311 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13314 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13315 A host in Prosody is a domain on which user accounts can be created. For
13316 example if you want your users to have addresses like
13317 @samp{"john.smith@@example.com"} then you need to add a host
13318 @samp{"example.com"}. All options in this list will apply only to this host.
13320 Note: the name "virtual" host is used in configuration to avoid confusion with
13321 the actual physical host that Prosody is installed on. A single Prosody
13322 instance can serve many domains, each one defined as a VirtualHost entry in
13323 Prosody's configuration. Conversely a server that hosts a single domain would
13324 have just one VirtualHost entry.
13326 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13328 Available @code{virtualhost-configuration} fields are:
13330 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:
13331 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13332 Domain you wish Prosody to serve.
13337 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13338 Components are extra services on a server which are available to clients,
13339 usually on a subdomain of the main server (such as
13340 @samp{"mycomponent.example.com"}). Example components might be chatroom
13341 servers, user directories, or gateways to other protocols.
13343 Internal components are implemented with Prosody-specific plugins. To add an
13344 internal component, you simply fill the hostname field, and the plugin you wish
13345 to use for the component.
13347 See @url{http://prosody.im/doc/components}.
13348 Defaults to @samp{()}.
13350 Available @code{int-component-configuration} fields are:
13352 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:
13353 @deftypevr {@code{int-component-configuration} parameter} string hostname
13354 Hostname of the component.
13357 @deftypevr {@code{int-component-configuration} parameter} string plugin
13358 Plugin you wish to use for the component.
13361 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13362 Multi-user chat (MUC) is Prosody's module for allowing you to create
13363 hosted chatrooms/conferences for XMPP users.
13365 General information on setting up and using multi-user chatrooms can be found
13366 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13367 which you should read if you are new to XMPP chatrooms.
13369 See also @url{http://prosody.im/doc/modules/mod_muc}.
13371 Available @code{mod-muc-configuration} fields are:
13373 @deftypevr {@code{mod-muc-configuration} parameter} string name
13374 The name to return in service discovery responses.
13375 Defaults to @samp{"Prosody Chatrooms"}.
13378 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13379 If @samp{#t}, this will only allow admins to create new chatrooms.
13380 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13381 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13382 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13383 restricts to service administrators only.
13384 Defaults to @samp{#f}.
13387 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13388 Maximum number of history messages that will be sent to the member that has
13389 just joined the room.
13390 Defaults to @samp{20}.
13397 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13398 External components use XEP-0114, which most standalone components
13399 support. To add an external component, you simply fill the hostname field. See
13400 @url{http://prosody.im/doc/components}.
13401 Defaults to @samp{()}.
13403 Available @code{ext-component-configuration} fields are:
13405 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:
13406 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13407 Password which the component will use to log in.
13410 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13411 Hostname of the component.
13416 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13417 Port(s) Prosody listens on for component connections.
13420 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13421 Interface Prosody listens on for component connections.
13422 Defaults to @samp{"127.0.0.1"}.
13425 It could be that you just want to get a @code{prosody.cfg.lua}
13426 up and running. In that case, you can pass an
13427 @code{opaque-prosody-configuration} record as the value of
13428 @code{prosody-service-type}. As its name indicates, an opaque configuration
13429 does not have easy reflective capabilities.
13430 Available @code{opaque-prosody-configuration} fields are:
13432 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13433 The prosody package.
13436 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13437 The contents of the @code{prosody.cfg.lua} to use.
13440 For example, if your @code{prosody.cfg.lua} is just the empty
13441 string, you could instantiate a prosody service like this:
13444 (service prosody-service-type
13445 (opaque-prosody-configuration
13446 (prosody.cfg.lua "")))
13449 @node Kerberos Services
13450 @subsubsection Kerberos Services
13453 The @code{(gnu services kerberos)} module provides services relating to
13454 the authentication protocol @dfn{Kerberos}.
13456 @subsubheading Krb5 Service
13458 Programs using a Kerberos client library normally
13459 expect a configuration file in @file{/etc/krb5.conf}.
13460 This service generates such a file from a definition provided in the
13461 operating system declaration.
13462 It does not cause any daemon to be started.
13464 No ``keytab'' files are provided by this service---you must explicitly create them.
13465 This service is known to work with the MIT client library, @code{mit-krb5}.
13466 Other implementations have not been tested.
13468 @defvr {Scheme Variable} krb5-service-type
13469 A service type for Kerberos 5 clients.
13473 Here is an example of its use:
13475 (service krb5-service-type
13476 (krb5-configuration
13477 (default-realm "EXAMPLE.COM")
13478 (allow-weak-crypto? #t)
13481 (name "EXAMPLE.COM")
13482 (admin-server "groucho.example.com")
13483 (kdc "karl.example.com"))
13486 (admin-server "kerb-admin.argrx.edu")
13487 (kdc "keys.argrx.edu"))))))
13491 This example provides a Kerberos@tie{}5 client configuration which:
13493 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13494 of which have distinct administration servers and key distribution centers;
13495 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13496 specified by clients;
13497 @item Accepts services which only support encryption types known to be weak.
13500 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13501 Only the most commonly used ones are described here.
13502 For a full list, and more detailed explanation of each, see the MIT
13503 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13507 @deftp {Data Type} krb5-realm
13508 @cindex realm, kerberos
13511 This field is a string identifying the name of the realm.
13512 A common convention is to use the fully qualified DNS name of your organization,
13513 converted to upper case.
13515 @item @code{admin-server}
13516 This field is a string identifying the host where the administration server is
13520 This field is a string identifying the key distribution center
13525 @deftp {Data Type} krb5-configuration
13528 @item @code{allow-weak-crypto?} (default: @code{#f})
13529 If this flag is @code{#t} then services which only offer encryption algorithms
13530 known to be weak will be accepted.
13532 @item @code{default-realm} (default: @code{#f})
13533 This field should be a string identifying the default Kerberos
13534 realm for the client.
13535 You should set this field to the name of your Kerberos realm.
13536 If this value is @code{#f}
13537 then a realm must be specified with every Kerberos principal when invoking programs
13538 such as @command{kinit}.
13540 @item @code{realms}
13541 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13543 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13549 @subsubheading PAM krb5 Service
13552 The @code{pam-krb5} service allows for login authentication and password
13553 management via Kerberos.
13554 You will need this service if you want PAM enabled applications to authenticate
13555 users using Kerberos.
13557 @defvr {Scheme Variable} pam-krb5-service-type
13558 A service type for the Kerberos 5 PAM module.
13561 @deftp {Data Type} pam-krb5-configuration
13562 Data type representing the configuration of the Kerberos 5 PAM module
13563 This type has the following parameters:
13565 @item @code{pam-krb5} (default: @code{pam-krb5})
13566 The pam-krb5 package to use.
13568 @item @code{minimum-uid} (default: @code{1000})
13569 The smallest user ID for which Kerberos authentications should be attempted.
13570 Local accounts with lower values will silently fail to authenticate.
13576 @subsubsection Web Services
13581 The @code{(gnu services web)} module provides the following service:
13583 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13584 [#:log-directory ``/var/log/nginx''] @
13585 [#:run-directory ``/var/run/nginx''] @
13586 [#:server-list '()] @
13587 [#:upstream-list '()] @
13588 [#:config-file @code{#f}]
13590 Return a service that runs @var{nginx}, the nginx web server.
13592 The nginx daemon loads its runtime configuration from @var{config-file}.
13593 Log files are written to @var{log-directory} and temporary runtime data
13594 files are written to @var{run-directory}. For proper operation, these
13595 arguments should match what is in @var{config-file} to ensure that the
13596 directories are created when the service is activated.
13598 As an alternative to using a @var{config-file}, @var{server-list} can be
13599 used to specify the list of @dfn{server blocks} required on the host and
13600 @var{upstream-list} can be used to specify a list of @dfn{upstream
13601 blocks} to configure. For this to work, use the default value for
13604 At startup, @command{nginx} has not yet read its configuration file, so it
13605 uses a default file to log error messages. If it fails to load its
13606 configuration file, that is where error messages are logged. After the
13607 configuration file is loaded, the default error log file changes as per
13608 configuration. In our case, startup error messages can be found in
13609 @file{/var/run/nginx/logs/error.log}, and after configuration in
13610 @file{/var/log/nginx/error.log}. The second location can be changed with the
13611 @var{log-directory} configuration option.
13615 @deffn {Scheme Variable} nginx-service-type
13616 This is type for the nginx web server.
13618 This service can be extended to add server blocks in addition to the
13619 default one, as in this example:
13622 (simple-service 'my-extra-server nginx-service-type
13623 (list (nginx-server-configuration
13625 (root "/srv/http/extra-website"))))
13629 @deftp {Data Type} nginx-server-configuration
13630 Data type representing the configuration of an nginx server block.
13631 This type has the following parameters:
13634 @item @code{http-port} (default: @code{80})
13635 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13636 nginx should not listen for HTTP (non secure) connection for this
13637 @dfn{server block}.
13639 @item @code{https-port} (default: @code{443})
13640 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13641 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13643 Note that nginx can listen for HTTP and HTTPS connections in the same
13644 @dfn{server block}.
13646 @item @code{server-name} (default: @code{(list 'default)})
13647 A list of server names this server represents. @code{'default} represents the
13648 default server for connections matching no other server.
13650 @item @code{root} (default: @code{"/srv/http"})
13651 Root of the website nginx will serve.
13653 @item @code{locations} (default: @code{'()})
13654 A list of @dfn{nginx-location-configuration} or
13655 @dfn{nginx-named-location-configuration} records to use within this
13658 @item @code{index} (default: @code{(list "index.html")})
13659 Index files to look for when clients ask for a directory. If it cannot be found,
13660 Nginx will send the list of files in the directory.
13662 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13663 Where to find the certificate for secure connections. Set it to @code{#f} if
13664 you don't have a certificate or you don't want to use HTTPS.
13666 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13667 Where to find the private key for secure connections. Set it to @code{#f} if
13668 you don't have a key or you don't want to use HTTPS.
13670 @item @code{server-tokens?} (default: @code{#f})
13671 Whether the server should add its configuration to response.
13676 @deftp {Data Type} nginx-upstream-configuration
13677 Data type representing the configuration of an nginx @code{upstream}
13678 block. This type has the following parameters:
13682 Name for this group of servers.
13684 @item @code{servers}
13685 Specify the addresses of the servers in the group. The address can be
13686 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13687 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13688 prefix @samp{unix:}. For addresses using an IP address or domain name,
13689 the default port is 80, and a different port can be specified
13695 @deftp {Data Type} nginx-location-configuration
13696 Data type representing the configuration of an nginx @code{location}
13697 block. This type has the following parameters:
13701 URI which this location block matches.
13703 @anchor{nginx-location-configuration body}
13705 Body of the location block, specified as a string. This can contain many
13706 configuration directives. For example, to pass requests to a upstream
13707 server group defined using an @code{nginx-upstream-configuration} block,
13708 the following directive would be specified in the body @samp{proxy_pass
13709 http://upstream-name;}.
13714 @deftp {Data Type} nginx-named-location-configuration
13715 Data type representing the configuration of an nginx named location
13716 block. Named location blocks are used for request redirection, and not
13717 used for regular request processing. This type has the following
13722 Name to identify this location block.
13725 @xref{nginx-location-configuration body}, as the body for named location
13726 blocks can be used in a similar way to the
13727 @code{nginx-location-configuration body}. One restriction is that the
13728 body of a named location block cannot contain location blocks.
13735 @subsubsection DNS Services
13736 @cindex DNS (domain name system)
13737 @cindex domain name system (DNS)
13739 The @code{(gnu services dns)} module provides services related to the
13740 @dfn{domain name system} (DNS). It provides a server service for hosting
13741 an @emph{authoritative} DNS server for multiple zones, slave or master.
13742 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
13744 An example configuration of an authoritative server for two zones, one master
13748 (define-zone-entries example.org.zone
13749 ;; Name TTL Class Type Data
13750 ("@@" "" "IN" "A" "127.0.0.1")
13751 ("@@" "" "IN" "NS" "ns")
13752 ("ns" "" "IN" "A" "127.0.0.1"))
13754 (define master-zone
13755 (knot-zone-configuration
13756 (domain "example.org")
13758 (origin "example.org")
13759 (entries example.org.zone)))))
13762 (knot-zone-configuration
13763 (domain "plop.org")
13764 (dnssec-policy "default")
13765 (master (list "plop-master"))))
13767 (define plop-master
13768 (knot-remote-configuration
13770 (address (list "208.76.58.171"))))
13774 (services (cons* (service knot-service-type
13775 (knot-confifguration
13776 (remotes (list plop-master))
13777 (zones (list master-zone slave-zone))))
13782 @deffn {Scheme Variable} knot-service-type
13783 This is the type for the Knot DNS server.
13785 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
13786 zones, that is to say domain names you would buy from a registrar. This server
13787 is not a resolver, meaning that it can only resolve names for which it is
13788 authoritative. This server can be configured to serve zones as a master server
13789 or a slave server as a per-zone basis. Slave zones will get their data from
13790 masters, and will serve it as an authoritative server. From the point of view
13791 of a resolver, there is no difference between master and slave.
13793 The following data types are used to configure the Knot DNS server:
13796 @deftp {Data Type} knot-key-configuration
13797 Data type representing a key.
13798 This type has the following parameters:
13801 @item @code{id} (default: @code{""})
13802 An identifier for other configuration fields to refer to this key. IDs must
13803 be unique and must not be empty.
13805 @item @code{algorithm} (default: @code{#f})
13806 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
13807 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
13808 and @code{'hmac-sha512}.
13810 @item @code{secret} (default: @code{""})
13811 The secret key itself.
13816 @deftp {Data Type} knot-acl-configuration
13817 Data type representing an Access Control List (ACL) configuration.
13818 This type has the following parameters:
13821 @item @code{id} (default: @code{""})
13822 An identifier for ether configuration fields to refer to this key. IDs must be
13823 unique and must not be empty.
13825 @item @code{address} (default: @code{'()})
13826 An ordered list of IP addresses, network subnets, or network ranges represented
13827 with strings. The query must match one of them. Empty value means that
13828 address match is not required.
13830 @item @code{key} (default: @code{'()})
13831 An ordered list of references to keys represented with strings. The string
13832 must match a key ID defined in a @code{knot-key-configuration}. No key means
13833 that a key is not require to match that ACL.
13835 @item @code{action} (default: @code{'()})
13836 An ordered list of actions that are permitted or forbidden by this ACL. Possible
13837 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
13838 and @code{'update}.
13840 @item @code{deny?} (default: @code{#f})
13841 When true, the ACL defines restrictions. Listed actions are forbidden. When
13842 false, listed actions are allowed.
13847 @deftp {Data Type} zone-entry
13848 Data type represnting a record entry in a zone file.
13849 This type has the following parameters:
13852 @item @code{name} (default: @code{"@@"})
13853 The name of the record. @code{"@@"} refers to the origin of the zone. Names
13854 are relative to the origin of the zone. For example, in the @code{example.org}
13855 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
13856 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
13857 refers to @code{ns.example.org}.
13859 @item @code{ttl} (default: @code{""})
13860 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
13862 @item @code{class} (default: @code{"IN"})
13863 The class of the record. Knot currently supports only @code{"IN"} and
13864 partially @code{"CH"}.
13866 @item @code{type} (default: @code{"A"})
13867 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
13868 address), NS (Name Server) and MX (Mail eXchange). Many other types are
13871 @item @code{data} (default: @code{""})
13872 The data contained in the record. For instance an IP address associated with
13873 an A record, or a domain name associated with an NS record. Remember that
13874 domain names are relative to the origin unless they end with a dot.
13879 @deftp {Data Type} zone-file
13880 Data type representing the content of a zone file.
13881 This type has the following parameters:
13884 @item @code{entries} (default: @code{'()})
13885 The list of entries. The SOA record is taken care of, so you don't need to
13886 put it in the list of entries. This list should probably contain an entry
13887 for your primary authoritative DNS server. Other than using a list of entries
13888 directly, you can use @code{define-zone-entries} to define a object containing
13889 the list of entries more easily, that you can later pass to the @code{entries}
13890 field of the @code{zone-file}.
13892 @item @code{origin} (default: @code{""})
13893 The name of your zone. This parameter cannot be empty.
13895 @item @code{ns} (default: @code{"ns"})
13896 The domain of your primary authoritative DNS server. The name is relative to
13897 the origin, unless it ends with a dot. It is mandatory that this primary
13898 DNS server corresponds to an NS record in the zone and that it is associated
13899 to an IP address in the list of entries.
13901 @item @code{mail} (default: @code{"hostmaster"})
13902 An email address people can contact you at, as the owner of the zone. This
13903 is translated as @code{<mail>@@<origin>}.
13905 @item @code{serial} (default: @code{1})
13906 The serial number of the zone. As this is used to keep track of changes by
13907 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
13908 Always increment it when you make a change in your zone.
13910 @item @code{refresh} (default: @code{(* 2 24 3600)})
13911 The frequency at which slaves will do a zone transfer. This value is a number
13912 of seconds. It can be computed by multiplications or with
13913 @code{(string->duration)}.
13915 @item @code{retry} (default: @code{(* 15 60)})
13916 The period after which a slave will retry to contact its master when it fails
13917 to do so a first time.
13919 @item @code{expiry} (default: @code{(* 14 24 3600)})
13920 Default TTL of records. Existing records are considered correct for at most
13921 this amount of time. After this period, resolvers will invalidate their cache
13922 and check again that it still exists.
13924 @item @code{nx} (default: @code{3600})
13925 Default TTL of inexistant records. This delay is usually short because you want
13926 your new domains to reach everyone quickly.
13931 @deftp {Data Type} knot-remote-configuration
13932 Data type representing a remote configuration.
13933 This type has the following parameters:
13936 @item @code{id} (default: @code{""})
13937 An identifier for other configuration fields to refer to this remote. IDs must
13938 be unique and must not be empty.
13940 @item @code{address} (default: @code{'()})
13941 An ordered list of destination IP addresses. Addresses are tried in sequence.
13942 An optional port can be given with the @@ separator. For instance:
13943 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
13945 @item @code{via} (default: @code{'()})
13946 An ordered list of source IP addresses. An empty list will have Knot choose
13947 an appropriate source IP. An optional port can be given with the @@ separator.
13948 The default is to choose at random.
13950 @item @code{key} (default: @code{#f})
13951 A reference to a key, that is a string containing the identifier of a key
13952 defined in a @code{knot-key-configuration} field.
13957 @deftp {Data Type} knot-keystore-configuration
13958 Data type representing a keystore to hold dnssec keys.
13959 This type has the following parameters:
13962 @item @code{id} (default: @code{""})
13963 The id of the keystore. It must not be empty.
13965 @item @code{backend} (default: @code{'pem})
13966 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
13968 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
13969 The configuration string of the backend. An example for the PKCS#11 is:
13970 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
13971 For the pem backend, the string reprensents a path in the filesystem.
13976 @deftp {Data Type} knot-policy-configuration
13977 Data type representing a dnssec policy. Knot DNS is able to automatically
13978 sign your zones. It can either generate and manage your keys automatically or
13979 use keys that you generate.
13981 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
13982 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
13983 zone. In order to be trusted, the KSK needs to be present in the parent zone
13984 (usually a top-level domain). If your registrar supports dnssec, you will
13985 have to send them your KSK's hash so they can add a DS record in their zone.
13986 This is not automated and need to be done each time you change your KSK.
13988 The policy also defines the lifetime of keys. Usually, ZSK can be changed
13989 easily and use weaker cryptographic functions (they use lower parameters) in
13990 order to sign records quickly, so they are changed often. The KSK however
13991 requires manual interaction with the registrar, so they are changed less often
13992 and use stronger parameters because they sign only one record.
13994 This type has the following parameters:
13997 @item @code{id} (default: @code{""})
13998 The id of the policy. It must not be empty.
14000 @item @code{keystore} (default: @code{"default"})
14001 A reference to a keystore, that is a string containing the identifier of a
14002 keystore defined in a @code{knot-keystore-configuration} field. The
14003 @code{"default"} identifier means the default keystore (a kasp database that
14004 was setup by this service).
14006 @item @code{manual?} (default: @code{#f})
14007 Whether the key management is manual or automatic.
14009 @item @code{single-type-signing?} (default: @code{#f})
14010 When @code{#t}, use the Single-Type Signing Scheme.
14012 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
14013 An algorithm of signing keys and issued signatures.
14015 @item @code{ksk-size} (default: @code{256})
14016 The length of the KSK. Note that this value is correct for the default
14017 algorithm, but would be unsecure for other algorithms.
14019 @item @code{zsk-size} (default: @code{256})
14020 The length of the ZSK. Note that this value is correct for the default
14021 algorithm, but would be unsecure for other algorithms.
14023 @item @code{dnskey-ttl} (default: @code{'default})
14024 The TTL value for DNSKEY records added into zone apex. The special
14025 @code{'default} value means same as the zone SOA TTL.
14027 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
14028 The period between ZSK publication and the next rollover initiation.
14030 @item @code{propagation-delay} (default: @code{(* 24 3600)})
14031 An extra delay added for each key rollover step. This value should be high
14032 enough to cover propagation of data from the master server to all slaves.
14034 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
14035 A validity period of newly issued signatures.
14037 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
14038 A period how long before a signature expiration the signature will be refreshed.
14040 @item @code{nsec3?} (default: @code{#f})
14041 When @code{#t}, NSEC3 will be used instead of NSEC.
14043 @item @code{nsec3-iterations} (default: @code{5})
14044 The number of additional times the hashing is performed.
14046 @item @code{nsec3-salt-length} (default: @code{8})
14047 The length of a salt field in octets, which is appended to the original owner
14048 name before hashing.
14050 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
14051 The validity period of newly issued salt field.
14056 @deftp {Data Type} knot-zone-configuration
14057 Data type representing a zone served by Knot.
14058 This type has the following parameters:
14061 @item @code{domain} (default: @code{""})
14062 The domain served by this configuration. It must not be empty.
14064 @item @code{file} (default: @code{""})
14065 The file where this zone is saved. This parameter is ignored by master zones.
14066 Empty means default location that depends on the domain name.
14068 @item @code{zone} (default: @code{(zone-file)})
14069 The content of the zone file. This parameter is ignored by slave zones. It
14070 must contain a zone-file record.
14072 @item @code{master} (default: @code{'()})
14073 A list of master remotes. When empty, this zone is a master. When set, this
14074 zone is a slave. This is a list of remotes identifiers.
14076 @item @code{ddns-master} (default: @code{#f})
14077 The main master. When empty, it defaults to the first master in the list of
14080 @item @code{notify} (default: @code{'()})
14081 A list of slave remote identifiers.
14083 @item @code{acl} (default: @code{'()})
14084 A list of acl identifiers.
14086 @item @code{semantic-checks?} (default: @code{#f})
14087 When set, this adds more semantic checks to the zone.
14089 @item @code{disable-any?} (default: @code{#f})
14090 When set, this forbids queries of the ANY type.
14092 @item @code{zonefile-sync} (default: @code{0})
14093 The delay between a modification in memory and on disk. 0 means immediate
14096 @item @code{serial-policy} (default: @code{'increment})
14097 A policy between @code{'increment} and @code{'unixtime}.
14102 @deftp {Data Type} knot-configuration
14103 Data type representing the Knot configuration.
14104 This type has the following parameters:
14107 @item @code{knot} (default: @code{knot})
14110 @item @code{run-directory} (default: @code{"/var/run/knot"})
14111 The run directory. This directory will be used for pid file and sockets.
14113 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14114 An ip address on which to listen.
14116 @item @code{listen-v6} (default: @code{"::"})
14117 An ip address on which to listen.
14119 @item @code{listen-port} (default: @code{53})
14120 A port on which to listen.
14122 @item @code{keys} (default: @code{'()})
14123 The list of knot-key-configuration used by this configuration.
14125 @item @code{acls} (default: @code{'()})
14126 The list of knot-acl-configuration used by this configuration.
14128 @item @code{remotes} (default: @code{'()})
14129 The list of knot-remote-configuration used by this configuration.
14131 @item @code{zones} (default: @code{'()})
14132 The list of knot-zone-configuration used by this configuration.
14138 @subsubsection VPN Services
14139 @cindex VPN (virtual private network)
14140 @cindex virtual private network (VPN)
14142 The @code{(gnu services vpn)} module provides services related to
14143 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14144 your machine to connect to a VPN, and a @emph{servire} service for your machine
14145 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14147 @deffn {Scheme Procedure} openvpn-client-service @
14148 [#:config (openvpn-client-configuration)]
14150 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14153 @deffn {Scheme Procedure} openvpn-server-service @
14154 [#:config (openvpn-server-configuration)]
14156 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14158 Both can be run simultaneously.
14161 @c %automatically generated documentation
14163 Available @code{openvpn-client-configuration} fields are:
14165 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14166 The OpenVPN package.
14170 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14171 The OpenVPN pid file.
14173 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14177 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14178 The protocol (UDP or TCP) used to open a channel between clients and
14181 Defaults to @samp{udp}.
14185 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14186 The device type used to represent the VPN connection.
14188 Defaults to @samp{tun}.
14192 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14193 The certificate authority to check connections against.
14195 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14199 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14200 The certificate of the machine the daemon is running on. It should be
14201 signed by the authority given in @code{ca}.
14203 Defaults to @samp{"/etc/openvpn/client.crt"}.
14207 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14208 The key of the machine the daemon is running on. It must be the key whose
14209 certificate is @code{cert}.
14211 Defaults to @samp{"/etc/openvpn/client.key"}.
14215 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14216 Whether to use the lzo compression algorithm.
14218 Defaults to @samp{#t}.
14222 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14223 Don't re-read key files across SIGUSR1 or --ping-restart.
14225 Defaults to @samp{#t}.
14229 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14230 Don't close and reopen TUN/TAP device or run up/down scripts across
14231 SIGUSR1 or --ping-restart restarts.
14233 Defaults to @samp{#t}.
14237 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14240 Defaults to @samp{3}.
14244 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14245 Add an additional layer of HMAC authentication on top of the TLS control
14246 channel to protect against DoS attacks.
14248 Defaults to @samp{#f}.
14252 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14253 Whether to check the server certificate has server usage extension.
14255 Defaults to @samp{#t}.
14259 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14260 Bind to a specific local port number.
14262 Defaults to @samp{#f}.
14266 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14267 Retry resolving server address.
14269 Defaults to @samp{#t}.
14273 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14274 A list of remote servers to connect to.
14276 Defaults to @samp{()}.
14278 Available @code{openvpn-remote-configuration} fields are:
14280 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14283 Defaults to @samp{"my-server"}.
14287 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14288 Port number the server listens to.
14290 Defaults to @samp{1194}.
14295 @c %end of automatic openvpn-client documentation
14297 @c %automatically generated documentation
14299 Available @code{openvpn-server-configuration} fields are:
14301 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14302 The OpenVPN package.
14306 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14307 The OpenVPN pid file.
14309 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14313 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14314 The protocol (UDP or TCP) used to open a channel between clients and
14317 Defaults to @samp{udp}.
14321 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14322 The device type used to represent the VPN connection.
14324 Defaults to @samp{tun}.
14328 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14329 The certificate authority to check connections against.
14331 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14335 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14336 The certificate of the machine the daemon is running on. It should be
14337 signed by the authority given in @code{ca}.
14339 Defaults to @samp{"/etc/openvpn/client.crt"}.
14343 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14344 The key of the machine the daemon is running on. It must be the key whose
14345 certificate is @code{cert}.
14347 Defaults to @samp{"/etc/openvpn/client.key"}.
14351 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14352 Whether to use the lzo compression algorithm.
14354 Defaults to @samp{#t}.
14358 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14359 Don't re-read key files across SIGUSR1 or --ping-restart.
14361 Defaults to @samp{#t}.
14365 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14366 Don't close and reopen TUN/TAP device or run up/down scripts across
14367 SIGUSR1 or --ping-restart restarts.
14369 Defaults to @samp{#t}.
14373 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14376 Defaults to @samp{3}.
14380 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14381 Add an additional layer of HMAC authentication on top of the TLS control
14382 channel to protect against DoS attacks.
14384 Defaults to @samp{#f}.
14388 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14389 Specifies the port number on which the server listens.
14391 Defaults to @samp{1194}.
14395 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14396 An ip and mask specifying the subnet inside the virtual network.
14398 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14402 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14403 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14405 Defaults to @samp{#f}.
14409 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14410 The Diffie-Hellman parameters file.
14412 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14416 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14417 The file that records client IPs.
14419 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
14423 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
14424 When true, the server will act as a gateway for its clients.
14426 Defaults to @samp{#f}.
14430 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
14431 When true, clients are allowed to talk to each other inside the VPN.
14433 Defaults to @samp{#f}.
14437 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
14438 Causes ping-like messages to be sent back and forth over the link so
14439 that each side knows when the other side has gone down. @code{keepalive}
14440 requires a pair. The first element is the period of the ping sending,
14441 and the second element is the timeout before considering the other side
14446 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
14447 The maximum number of clients.
14449 Defaults to @samp{100}.
14453 @deftypevr {@code{openvpn-server-configuration} parameter} string status
14454 The status file. This file shows a small report on current connection.
14455 It is truncated and rewritten every minute.
14457 Defaults to @samp{"/var/run/openvpn/status"}.
14461 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
14462 The list of configuration for some clients.
14464 Defaults to @samp{()}.
14466 Available @code{openvpn-ccd-configuration} fields are:
14468 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
14471 Defaults to @samp{"client"}.
14475 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
14478 Defaults to @samp{#f}.
14482 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
14485 Defaults to @samp{#f}.
14492 @c %end of automatic openvpn-server documentation
14495 @node Network File System
14496 @subsubsection Network File System
14499 The @code{(gnu services nfs)} module provides the following services,
14500 which are most commonly used in relation to mounting or exporting
14501 directory trees as @dfn{network file systems} (NFS).
14503 @subsubheading RPC Bind Service
14506 The RPC Bind service provides a facility to map program numbers into
14507 universal addresses.
14508 Many NFS related services use this facility. Hence it is automatically
14509 started when a dependent service starts.
14511 @defvr {Scheme Variable} rpcbind-service-type
14512 A service type for the RPC portmapper daemon.
14516 @deftp {Data Type} rpcbind-configuration
14517 Data type representing the configuration of the RPC Bind Service.
14518 This type has the following parameters:
14520 @item @code{rpcbind} (default: @code{rpcbind})
14521 The rpcbind package to use.
14523 @item @code{warm-start?} (default: @code{#t})
14524 If this parameter is @code{#t}, then the daemon will read a
14525 state file on startup thus reloading state information saved by a previous
14531 @subsubheading Pipefs Pseudo File System
14535 The pipefs file system is used to transfer NFS related data
14536 between the kernel and user space programs.
14538 @defvr {Scheme Variable} pipefs-service-type
14539 A service type for the pipefs pseudo file system.
14542 @deftp {Data Type} pipefs-configuration
14543 Data type representing the configuration of the pipefs pseudo file system service.
14544 This type has the following parameters:
14546 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14547 The directory to which the file system is to be attached.
14552 @subsubheading GSS Daemon Service
14555 @cindex global security system
14557 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14559 Before exchanging RPC requests an RPC client must establish a security
14560 context. Typically this is done using the Kerberos command @command{kinit}
14561 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14563 @defvr {Scheme Variable} gss-service-type
14564 A service type for the Global Security System (GSS) daemon.
14567 @deftp {Data Type} gss-configuration
14568 Data type representing the configuration of the GSS daemon service.
14569 This type has the following parameters:
14571 @item @code{nfs-utils} (default: @code{nfs-utils})
14572 The package in which the @command{rpc.gssd} command is to be found.
14574 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14575 The directory where the pipefs file system is mounted.
14581 @subsubheading IDMAP Daemon Service
14583 @cindex name mapper
14585 The idmap daemon service provides mapping between user IDs and user names.
14586 Typically it is required in order to access file systems mounted via NFSv4.
14588 @defvr {Scheme Variable} idmap-service-type
14589 A service type for the Identity Mapper (IDMAP) daemon.
14592 @deftp {Data Type} idmap-configuration
14593 Data type representing the configuration of the IDMAP daemon service.
14594 This type has the following parameters:
14596 @item @code{nfs-utils} (default: @code{nfs-utils})
14597 The package in which the @command{rpc.idmapd} command is to be found.
14599 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14600 The directory where the pipefs file system is mounted.
14602 @item @code{domain} (default: @code{#f})
14603 The local NFSv4 domain name.
14604 This must be a string or @code{#f}.
14605 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14610 @node Continuous Integration
14611 @subsubsection Continuous Integration
14613 @cindex continuous integration
14614 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14615 integration tool for Guix. It can be used both for development and for
14616 providing substitutes to others (@pxref{Substitutes}).
14618 The @code{(gnu services cuirass)} module provides the following service.
14620 @defvr {Scheme Procedure} cuirass-service-type
14621 The type of the Cuirass service. Its value must be a
14622 @code{cuirass-configuration} object, as described below.
14625 To add build jobs, you have to set the @code{specifications} field of
14626 the configuration. Here is an example of a service defining a build job
14627 based on a specification that can be found in Cuirass source tree. This
14628 service polls the Guix repository and builds a subset of the Guix
14629 packages, as prescribed in the @file{gnu-system.scm} example spec:
14632 (let ((spec #~((#:name . "guix")
14633 (#:url . "git://git.savannah.gnu.org/guix.git")
14634 (#:load-path . ".")
14636 ;; Here we must provide an absolute file name.
14637 ;; We take jobs from one of the examples provided
14639 (#:file . #$(file-append
14641 "/tests/gnu-system.scm"))
14643 (#:proc . hydra-jobs)
14644 (#:arguments (subset . "hello"))
14645 (#:branch . "master"))))
14646 (service cuirass-service-type
14647 (cuirass-configuration
14648 (specifications #~(list #$spec)))))
14651 While information related to build jobs is located directly in the
14652 specifications, global settings for the @command{cuirass} process are
14653 accessible in other @code{cuirass-configuration} fields.
14655 @deftp {Data Type} cuirass-configuration
14656 Data type representing the configuration of Cuirass.
14659 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14660 Location of the log file.
14662 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14663 Location of the repository cache.
14665 @item @code{user} (default: @code{"cuirass"})
14666 Owner of the @code{cuirass} process.
14668 @item @code{group} (default: @code{"cuirass"})
14669 Owner's group of the @code{cuirass} process.
14671 @item @code{interval} (default: @code{60})
14672 Number of seconds between the poll of the repositories followed by the
14675 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14676 Location of sqlite database which contains the build results and previously
14677 added specifications.
14679 @item @code{port} (default: @code{8080})
14680 Port number used by the HTTP server.
14682 @item @code{specifications} (default: @code{#~'()})
14683 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14684 where a specification is an association list
14685 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14686 keys are keywords (@code{#:keyword-example}) as shown in the example
14689 @item @code{use-substitutes?} (default: @code{#f})
14690 This allows using substitutes to avoid building every dependencies of a job
14693 @item @code{one-shot?} (default: @code{#f})
14694 Only evaluate specifications and build derivations once.
14696 @item @code{load-path} (default: @code{'()})
14697 This allows users to define their own packages and make them visible to
14698 cuirass as in @command{guix build} command.
14700 @item @code{cuirass} (default: @code{cuirass})
14701 The Cuirass package to use.
14705 @node Power management Services
14706 @subsubsection Power management Services
14708 @cindex power management with TLP
14709 The @code{(gnu services pm)} module provides a Guix service definition
14710 for the Linux power management tool TLP.
14712 TLP enables various powersaving modes in userspace and kernel.
14713 Contrary to @code{upower-service}, it is not a passive,
14714 monitoring tool, as it will apply custom settings each time a new power
14715 source is detected. More information can be found at
14716 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14718 @deffn {Scheme Variable} tlp-service-type
14719 The service type for the TLP tool. Its value should be a valid
14720 TLP configuration (see below). To use the default settings, simply
14723 (service tlp-service-type)
14727 By default TLP does not need much configuration but most TLP parameters
14728 can be tweaked using @code{tlp-configuration}.
14730 Each parameter definition is preceded by its type; for example,
14731 @samp{boolean foo} indicates that the @code{foo} parameter
14732 should be specified as a boolean. Types starting with
14733 @code{maybe-} denote parameters that won't show up in TLP config file
14734 when their value is @code{'disabled}.
14736 @c The following documentation was initially generated by
14737 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14738 @c documentation is better, so we shouldn't hesitate to edit below as
14739 @c needed. However if the change you want to make to this documentation
14740 @c can be done in an automated way, it's probably easier to change
14741 @c (generate-documentation) than to make it below and have to deal with
14742 @c the churn as TLP updates.
14744 Available @code{tlp-configuration} fields are:
14746 @deftypevr {@code{tlp-configuration} parameter} package tlp
14751 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14752 Set to true if you wish to enable TLP.
14754 Defaults to @samp{#t}.
14758 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14759 Default mode when no power supply can be detected. Alternatives are AC
14762 Defaults to @samp{"AC"}.
14766 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14767 Number of seconds Linux kernel has to wait after the disk goes idle,
14768 before syncing on AC.
14770 Defaults to @samp{0}.
14774 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14775 Same as @code{disk-idle-ac} but on BAT mode.
14777 Defaults to @samp{2}.
14781 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14782 Dirty pages flushing periodicity, expressed in seconds.
14784 Defaults to @samp{15}.
14788 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14789 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14791 Defaults to @samp{60}.
14795 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14796 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14797 alternatives are powersave and performance. With acpi-cpufreq driver,
14798 alternatives are ondemand, powersave, performance and conservative.
14800 Defaults to @samp{disabled}.
14804 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14805 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14807 Defaults to @samp{disabled}.
14811 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14812 Set the min available frequency for the scaling governor on AC.
14814 Defaults to @samp{disabled}.
14818 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14819 Set the max available frequency for the scaling governor on AC.
14821 Defaults to @samp{disabled}.
14825 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14826 Set the min available frequency for the scaling governor on BAT.
14828 Defaults to @samp{disabled}.
14832 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14833 Set the max available frequency for the scaling governor on BAT.
14835 Defaults to @samp{disabled}.
14839 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14840 Limit the min P-state to control the power dissipation of the CPU, in AC
14841 mode. Values are stated as a percentage of the available performance.
14843 Defaults to @samp{disabled}.
14847 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14848 Limit the max P-state to control the power dissipation of the CPU, in AC
14849 mode. Values are stated as a percentage of the available performance.
14851 Defaults to @samp{disabled}.
14855 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14856 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14858 Defaults to @samp{disabled}.
14862 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14863 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14865 Defaults to @samp{disabled}.
14869 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14870 Enable CPU turbo boost feature on AC mode.
14872 Defaults to @samp{disabled}.
14876 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14877 Same as @code{cpu-boost-on-ac?} on BAT mode.
14879 Defaults to @samp{disabled}.
14883 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14884 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14885 used under light load conditions.
14887 Defaults to @samp{#f}.
14891 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14892 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14894 Defaults to @samp{#t}.
14898 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14899 Enable Linux kernel NMI watchdog.
14901 Defaults to @samp{#f}.
14905 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14906 For Linux kernels with PHC patch applied, change CPU voltages. An
14907 example value would be @samp{"F:V F:V F:V F:V"}.
14909 Defaults to @samp{disabled}.
14913 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14914 Set CPU performance versus energy saving policy on AC. Alternatives are
14915 performance, normal, powersave.
14917 Defaults to @samp{"performance"}.
14921 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14922 Same as @code{energy-perf-policy-ac} but on BAT mode.
14924 Defaults to @samp{"powersave"}.
14928 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14933 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14934 Hard disk advanced power management level.
14938 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14939 Same as @code{disk-apm-bat} but on BAT mode.
14943 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14944 Hard disk spin down timeout. One value has to be specified for each
14945 declared hard disk.
14947 Defaults to @samp{disabled}.
14951 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14952 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14954 Defaults to @samp{disabled}.
14958 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14959 Select IO scheduler for disk devices. One value has to be specified for
14960 each declared hard disk. Example alternatives are cfq, deadline and
14963 Defaults to @samp{disabled}.
14967 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14968 SATA aggressive link power management (ALPM) level. Alternatives are
14969 min_power, medium_power, max_performance.
14971 Defaults to @samp{"max_performance"}.
14975 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14976 Same as @code{sata-linkpwr-ac} but on BAT mode.
14978 Defaults to @samp{"min_power"}.
14982 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14983 Exclude specified SATA host devices for link power management.
14985 Defaults to @samp{disabled}.
14989 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14990 Enable Runtime Power Management for AHCI controller and disks on AC
14993 Defaults to @samp{disabled}.
14997 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14998 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
15000 Defaults to @samp{disabled}.
15004 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
15005 Seconds of inactivity before disk is suspended.
15007 Defaults to @samp{15}.
15011 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
15012 PCI Express Active State Power Management level. Alternatives are
15013 default, performance, powersave.
15015 Defaults to @samp{"performance"}.
15019 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
15020 Same as @code{pcie-aspm-ac} but on BAT mode.
15022 Defaults to @samp{"powersave"}.
15026 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
15027 Radeon graphics clock speed level. Alternatives are low, mid, high,
15030 Defaults to @samp{"high"}.
15034 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
15035 Same as @code{radeon-power-ac} but on BAT mode.
15037 Defaults to @samp{"low"}.
15041 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
15042 Radeon dynamic power management method (DPM). Alternatives are battery,
15045 Defaults to @samp{"performance"}.
15049 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
15050 Same as @code{radeon-dpm-state-ac} but on BAT mode.
15052 Defaults to @samp{"battery"}.
15056 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
15057 Radeon DPM performance level. Alternatives are auto, low, high.
15059 Defaults to @samp{"auto"}.
15063 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
15064 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
15066 Defaults to @samp{"auto"}.
15070 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
15071 Wifi power saving mode.
15073 Defaults to @samp{#f}.
15077 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
15078 Same as @code{wifi-power-ac?} but on BAT mode.
15080 Defaults to @samp{#t}.
15084 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
15085 Disable wake on LAN.
15087 Defaults to @samp{#t}.
15091 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
15092 Timeout duration in seconds before activating audio power saving on
15093 Intel HDA and AC97 devices. A value of 0 disables power saving.
15095 Defaults to @samp{0}.
15099 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
15100 Same as @code{sound-powersave-ac} but on BAT mode.
15102 Defaults to @samp{1}.
15106 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15107 Disable controller in powersaving mode on Intel HDA devices.
15109 Defaults to @samp{#t}.
15113 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15114 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15115 powered on again by releasing (and reinserting) the eject lever or by
15116 pressing the disc eject button on newer models.
15118 Defaults to @samp{#f}.
15122 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15123 Name of the optical drive device to power off.
15125 Defaults to @samp{"sr0"}.
15129 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15130 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15133 Defaults to @samp{"on"}.
15137 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15138 Same as @code{runtime-pm-ac} but on BAT mode.
15140 Defaults to @samp{"auto"}.
15144 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15145 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15148 Defaults to @samp{#t}.
15152 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15153 Exclude specified PCI(e) device addresses from Runtime Power Management.
15155 Defaults to @samp{disabled}.
15159 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15160 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15165 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15166 Enable USB autosuspend feature.
15168 Defaults to @samp{#t}.
15172 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15173 Exclude specified devices from USB autosuspend.
15175 Defaults to @samp{disabled}.
15179 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15180 Exclude WWAN devices from USB autosuspend.
15182 Defaults to @samp{#t}.
15186 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15187 Include specified devices into USB autosuspend, even if they are already
15188 excluded by the driver or via @code{usb-blacklist-wwan?}.
15190 Defaults to @samp{disabled}.
15194 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15195 Enable USB autosuspend before shutdown.
15197 Defaults to @samp{disabled}.
15201 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15202 Restore radio device state (bluetooth, wifi, wwan) from previous
15203 shutdown on system startup.
15205 Defaults to @samp{#f}.
15210 The @code{(gnu services pm)} module provides an interface to
15211 thermald, a CPU frequency scaling service which helps prevent overheating.
15213 @defvr {Scheme Variable} thermald-service-type
15214 This is the service type for
15215 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15216 Thermal Daemon, which is responsible for controlling the thermal state
15217 of processors and preventing overheating.
15220 @deftp {Data Type} thermald-configuration
15221 Data type representing the configuration of @code{thermald-service-type}.
15224 @item @code{ignore-cpuid-check?} (default: @code{#f})
15225 Ignore cpuid check for supported CPU models.
15227 @item @code{thermald} (default: @var{thermald})
15228 Package object of thermald.
15234 @node Miscellaneous Services
15235 @subsubsection Miscellaneous Services
15239 @subsubheading Lirc Service
15241 The @code{(gnu services lirc)} module provides the following service.
15243 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
15244 [#:device #f] [#:driver #f] [#:config-file #f] @
15245 [#:extra-options '()]
15246 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
15247 decodes infrared signals from remote controls.
15249 Optionally, @var{device}, @var{driver} and @var{config-file}
15250 (configuration file name) may be specified. See @command{lircd} manual
15253 Finally, @var{extra-options} is a list of additional command-line options
15254 passed to @command{lircd}.
15258 @subsubheading Spice Service
15260 The @code{(gnu services spice)} module provides the following service.
15262 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
15263 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
15264 that enables sharing the clipboard with a vm and setting the guest display
15265 resolution when the graphical console window resizes.
15268 @subsubsection Dictionary Services
15270 The @code{(gnu services dict)} module provides the following service:
15272 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
15273 Return a service that runs the @command{dicod} daemon, an implementation
15274 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
15276 The optional @var{config} argument specifies the configuration for
15277 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
15278 default it serves the GNU Collaborative International Dictonary of English.
15280 You can add @command{open localhost} to your @file{~/.dico} file to make
15281 @code{localhost} the default server for @command{dico} client
15282 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
15285 @deftp {Data Type} dicod-configuration
15286 Data type representing the configuration of dicod.
15289 @item @code{dico} (default: @var{dico})
15290 Package object of the GNU Dico dictionary server.
15292 @item @code{interfaces} (default: @var{'("localhost")})
15293 This is the list of IP addresses and ports and possibly socket file
15294 names to listen to (@pxref{Server Settings, @code{listen} directive,,
15295 dico, GNU Dico Manual}).
15297 @item @code{handlers} (default: @var{'()})
15298 List of @code{<dicod-handler>} objects denoting handlers (module instances).
15300 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
15301 List of @code{<dicod-database>} objects denoting dictionaries to be served.
15305 @deftp {Data Type} dicod-handler
15306 Data type representing a dictionary handler (module instance).
15310 Name of the handler (module instance).
15312 @item @code{module} (default: @var{#f})
15313 Name of the dicod module of the handler (instance). If it is @code{#f},
15314 the module has the same name as the handler.
15315 (@pxref{Modules,,, dico, GNU Dico Manual}).
15317 @item @code{options}
15318 List of strings or gexps representing the arguments for the module handler
15322 @deftp {Data Type} dicod-database
15323 Data type representing a dictionary database.
15327 Name of the database, will be used in DICT commands.
15329 @item @code{handler}
15330 Name of the dicod handler (module instance) used by this database
15331 (@pxref{Handlers,,, dico, GNU Dico Manual}).
15333 @item @code{complex?} (default: @var{#f})
15334 Whether the database configuration complex. The complex configuration
15335 will need a corresponding @code{<dicod-handler>} object, otherwise not.
15337 @item @code{options}
15338 List of strings or gexps representing the arguments for the database
15339 (@pxref{Databases,,, dico, GNU Dico Manual}).
15343 @defvr {Scheme Variable} %dicod-database:gcide
15344 A @code{<dicod-database>} object serving the GNU Collaborative International
15345 Dictionary of English using the @code{gcide} package.
15348 The following is an example @code{dicod-service} configuration.
15351 (dicod-service #:config
15352 (dicod-configuration
15353 (handlers (list (dicod-handler
15357 (list #~(string-append "dbdir=" #$wordnet))))))
15358 (databases (list (dicod-database
15361 (handler "wordnet")
15362 (options '("database=wn")))
15363 %dicod-database:gcide))))
15366 @subsubsection Version Control
15368 The @code{(gnu services version-control)} module provides the following services:
15370 @subsubheading Git daemon service
15372 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
15374 Return a service that runs @command{git daemon}, a simple TCP server to
15375 expose repositories over the Git protocol for anonymous access.
15377 The optional @var{config} argument should be a
15378 @code{<git-daemon-configuration>} object, by default it allows read-only
15379 access to exported@footnote{By creating the magic file
15380 "git-daemon-export-ok" in the repository directory.} repositories under
15385 @deftp {Data Type} git-daemon-configuration
15386 Data type representing the configuration for @code{git-daemon-service}.
15389 @item @code{package} (default: @var{git})
15390 Package object of the Git distributed version control system.
15392 @item @code{export-all?} (default: @var{#f})
15393 Whether to allow access for all Git repositories, even if they do not
15394 have the @file{git-daemon-export-ok} file.
15396 @item @code{base-path} (default: @file{/srv/git})
15397 Whether to remap all the path requests as relative to the given path.
15398 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
15399 then if you later try to pull @code{git://example.com/hello.git}, git
15400 daemon will interpret the path as @code{/srv/git/hello.git}.
15402 @item @code{user-path} (default: @var{#f})
15403 Whether to allow @code{~user} notation to be used in requests. When
15404 specified with empty string, requests to @code{git://host/~alice/foo} is
15405 taken as a request to access @code{foo} repository in the home directory
15406 of user @code{alice}. If @var{(user-path "path")} is specified, the
15407 same request is taken as a request to access @code{path/foo} repository
15408 in the home directory of user @code{alice}.
15410 @item @code{listen} (default: @var{'()})
15411 Whether to listen on specific IP addresses or hostnames, defaults to
15414 @item @code{port} (default: @var{#f})
15415 Whether to listen on an alternative port, which defaults to 9418.
15417 @item @code{whitelist} (default: @var{'()})
15418 If not empty, only allow access to this list of directories.
15420 @item @code{extra-options} (default: @var{'()})
15421 Extra options will be passed to @code{git daemon}, please run
15422 @command{man git-daemon} for more information.
15427 @node Setuid Programs
15428 @subsection Setuid Programs
15430 @cindex setuid programs
15431 Some programs need to run with ``root'' privileges, even when they are
15432 launched by unprivileged users. A notorious example is the
15433 @command{passwd} program, which users can run to change their
15434 password, and which needs to access the @file{/etc/passwd} and
15435 @file{/etc/shadow} files---something normally restricted to root, for
15436 obvious security reasons. To address that, these executables are
15437 @dfn{setuid-root}, meaning that they always run with root privileges
15438 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
15439 for more info about the setuid mechanism.)
15441 The store itself @emph{cannot} contain setuid programs: that would be a
15442 security issue since any user on the system can write derivations that
15443 populate the store (@pxref{The Store}). Thus, a different mechanism is
15444 used: instead of changing the setuid bit directly on files that are in
15445 the store, we let the system administrator @emph{declare} which programs
15446 should be setuid root.
15448 The @code{setuid-programs} field of an @code{operating-system}
15449 declaration contains a list of G-expressions denoting the names of
15450 programs to be setuid-root (@pxref{Using the Configuration System}).
15451 For instance, the @command{passwd} program, which is part of the Shadow
15452 package, can be designated by this G-expression (@pxref{G-Expressions}):
15455 #~(string-append #$shadow "/bin/passwd")
15458 A default set of setuid programs is defined by the
15459 @code{%setuid-programs} variable of the @code{(gnu system)} module.
15461 @defvr {Scheme Variable} %setuid-programs
15462 A list of G-expressions denoting common programs that are setuid-root.
15464 The list includes commands such as @command{passwd}, @command{ping},
15465 @command{su}, and @command{sudo}.
15468 Under the hood, the actual setuid programs are created in the
15469 @file{/run/setuid-programs} directory at system activation time. The
15470 files in this directory refer to the ``real'' binaries, which are in the
15473 @node X.509 Certificates
15474 @subsection X.509 Certificates
15476 @cindex HTTPS, certificates
15477 @cindex X.509 certificates
15479 Web servers available over HTTPS (that is, HTTP over the transport-layer
15480 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
15481 that the client can then use to @emph{authenticate} the server. To do
15482 that, clients verify that the server's certificate is signed by a
15483 so-called @dfn{certificate authority} (CA). But to verify the CA's
15484 signature, clients must have first acquired the CA's certificate.
15486 Web browsers such as GNU@tie{}IceCat include their own set of CA
15487 certificates, such that they are able to verify CA signatures
15490 However, most other programs that can talk HTTPS---@command{wget},
15491 @command{git}, @command{w3m}, etc.---need to be told where CA
15492 certificates can be found.
15494 @cindex @code{nss-certs}
15495 In GuixSD, this is done by adding a package that provides certificates
15496 to the @code{packages} field of the @code{operating-system} declaration
15497 (@pxref{operating-system Reference}). GuixSD includes one such package,
15498 @code{nss-certs}, which is a set of CA certificates provided as part of
15499 Mozilla's Network Security Services.
15501 Note that it is @emph{not} part of @var{%base-packages}, so you need to
15502 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
15503 most applications and libraries look for certificates by default, points
15504 to the certificates installed globally.
15506 Unprivileged users, including users of Guix on a foreign distro,
15507 can also install their own certificate package in
15508 their profile. A number of environment variables need to be defined so
15509 that applications and libraries know where to find them. Namely, the
15510 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
15511 variables. Some applications add their own environment variables; for
15512 instance, the Git version control system honors the certificate bundle
15513 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
15514 would typically run something like:
15517 $ guix package -i nss-certs
15518 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
15519 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15520 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
15523 As another example, R requires the @code{CURL_CA_BUNDLE} environment
15524 variable to point to a certificate bundle, so you would have to run
15525 something like this:
15528 $ guix package -i nss-certs
15529 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15532 For other applications you may want to look up the required environment
15533 variable in the relevant documentation.
15536 @node Name Service Switch
15537 @subsection Name Service Switch
15539 @cindex name service switch
15541 The @code{(gnu system nss)} module provides bindings to the
15542 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
15543 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
15544 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
15545 extended with new ``name'' lookup methods for system databases, which
15546 includes host names, service names, user accounts, and more (@pxref{Name
15547 Service Switch, System Databases and Name Service Switch,, libc, The GNU
15548 C Library Reference Manual}).
15550 The NSS configuration specifies, for each system database, which lookup
15551 method is to be used, and how the various methods are chained
15552 together---for instance, under which circumstances NSS should try the
15553 next method in the list. The NSS configuration is given in the
15554 @code{name-service-switch} field of @code{operating-system} declarations
15555 (@pxref{operating-system Reference, @code{name-service-switch}}).
15558 @cindex .local, host name lookup
15559 As an example, the declaration below configures the NSS to use the
15560 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15561 back-end}, which supports host name lookups over multicast DNS (mDNS)
15562 for host names ending in @code{.local}:
15565 (name-service-switch
15566 (hosts (list %files ;first, check /etc/hosts
15568 ;; If the above did not succeed, try
15569 ;; with 'mdns_minimal'.
15571 (name "mdns_minimal")
15573 ;; 'mdns_minimal' is authoritative for
15574 ;; '.local'. When it returns "not found",
15575 ;; no need to try the next methods.
15576 (reaction (lookup-specification
15577 (not-found => return))))
15579 ;; Then fall back to DNS.
15583 ;; Finally, try with the "full" 'mdns'.
15588 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15589 contains this configuration, so you will not have to type it if all you
15590 want is to have @code{.local} host lookup working.
15592 Note that, in this case, in addition to setting the
15593 @code{name-service-switch} of the @code{operating-system} declaration,
15594 you also need to use @code{avahi-service} (@pxref{Networking Services,
15595 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15596 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15597 to the name service cache daemon (@pxref{Base Services,
15598 @code{nscd-service}}).
15600 For convenience, the following variables provide typical NSS
15603 @defvr {Scheme Variable} %default-nss
15604 This is the default name service switch configuration, a
15605 @code{name-service-switch} object.
15608 @defvr {Scheme Variable} %mdns-host-lookup-nss
15609 This is the name service switch configuration with support for host name
15610 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
15613 The reference for name service switch configuration is given below. It
15614 is a direct mapping of the configuration file format of the C library , so
15615 please refer to the C library manual for more information (@pxref{NSS
15616 Configuration File,,, libc, The GNU C Library Reference Manual}).
15617 Compared to the configuration file format of libc NSS, it has the advantage
15618 not only of adding this warm parenthetic feel that we like, but also
15619 static checks: you will know about syntax errors and typos as soon as you
15620 run @command{guix system}.
15622 @deftp {Data Type} name-service-switch
15624 This is the data type representation the configuration of libc's name
15625 service switch (NSS). Each field below represents one of the supported
15642 The system databases handled by the NSS. Each of these fields must be a
15643 list of @code{<name-service>} objects (see below).
15647 @deftp {Data Type} name-service
15649 This is the data type representing an actual name service and the
15650 associated lookup action.
15654 A string denoting the name service (@pxref{Services in the NSS
15655 configuration,,, libc, The GNU C Library Reference Manual}).
15657 Note that name services listed here must be visible to nscd. This is
15658 achieved by passing the @code{#:name-services} argument to
15659 @code{nscd-service} the list of packages providing the needed name
15660 services (@pxref{Base Services, @code{nscd-service}}).
15663 An action specified using the @code{lookup-specification} macro
15664 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15665 Reference Manual}). For example:
15668 (lookup-specification (unavailable => continue)
15669 (success => return))
15674 @node Initial RAM Disk
15675 @subsection Initial RAM Disk
15678 @cindex initial RAM disk
15679 For bootstrapping purposes, the Linux-Libre kernel is passed an
15680 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15681 root file system as well as an initialization script. The latter is
15682 responsible for mounting the real root file system, and for loading any
15683 kernel modules that may be needed to achieve that.
15685 The @code{initrd} field of an @code{operating-system} declaration allows
15686 you to specify which initrd you would like to use. The @code{(gnu
15687 system linux-initrd)} module provides three ways to build an initrd: the
15688 high-level @code{base-initrd} procedure and the low-level
15689 @code{raw-initrd} and @code{expression->initrd} procedures.
15691 The @code{base-initrd} procedure is intended to cover most common uses.
15692 For example, if you want to add a bunch of kernel modules to be loaded
15693 at boot time, you can define the @code{initrd} field of the operating
15694 system declaration like this:
15697 (initrd (lambda (file-systems . rest)
15698 ;; Create a standard initrd that has modules "foo.ko"
15699 ;; and "bar.ko", as well as their dependencies, in
15700 ;; addition to the modules available by default.
15701 (apply base-initrd file-systems
15702 #:extra-modules '("foo" "bar")
15706 The @code{base-initrd} procedure also handles common use cases that
15707 involves using the system as a QEMU guest, or as a ``live'' system with
15708 volatile root file system.
15710 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15711 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15712 such as trying to guess which kernel modules and packages should be included
15713 to the initrd. An example use of @code{raw-initrd} is when a user has
15714 a custom Linux kernel configuration and default kernel modules included by
15715 @code{base-initrd} are not available.
15717 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15718 honors several options passed on the Linux kernel command line
15719 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15720 @code{-append} option of QEMU), notably:
15723 @item --load=@var{boot}
15724 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15725 program, once it has mounted the root file system.
15727 GuixSD uses this option to yield control to a boot program that runs the
15728 service activation programs and then spawns the GNU@tie{}Shepherd, the
15729 initialization system.
15731 @item --root=@var{root}
15732 Mount @var{root} as the root file system. @var{root} can be a
15733 device name like @code{/dev/sda1}, a partition label, or a partition
15736 @item --system=@var{system}
15737 Have @file{/run/booted-system} and @file{/run/current-system} point to
15740 @item modprobe.blacklist=@var{modules}@dots{}
15741 @cindex module, black-listing
15742 @cindex black list, of kernel modules
15743 Instruct the initial RAM disk as well as the @command{modprobe} command
15744 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15745 must be a comma-separated list of module names---e.g.,
15746 @code{usbkbd,9pnet}.
15749 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15750 tries to load kernel modules and to mount the root file system. Our
15751 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15752 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15753 Manual}, for more information on Guile's REPL.
15757 Now that you know all the features that initial RAM disks produced by
15758 @code{base-initrd} and @code{raw-initrd} provide,
15759 here is how to use it and customize it further.
15762 @cindex initial RAM disk
15763 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15764 [#:linux-modules '()] [#:mapped-devices '()] @
15765 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15766 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15767 a list of file systems to be mounted by the initrd, possibly in addition to
15768 the root file system specified on the kernel command line via @code{--root}.
15769 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15770 @var{mapped-devices} is a list of device mappings to realize before
15771 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15772 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15773 include @code{e2fsck/static} or other packages needed by the initrd to check
15776 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15777 parameters. When @var{virtio?} is true, load additional modules so that the
15778 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15780 When @var{volatile-root?} is true, the root file system is writable but any changes
15784 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15785 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15786 [#:virtio? #t] [#:extra-modules '()]
15787 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15788 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15789 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15790 also behaves as in @code{raw-initrd}.
15792 When @var{virtio?} is true, load additional modules so that the
15793 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15795 The initrd is automatically populated with all the kernel modules necessary
15796 for @var{file-systems} and for the given options. However, additional kernel
15797 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15798 loaded at boot time in the order in which they appear.
15801 Needless to say, the initrds we produce and use embed a
15802 statically-linked Guile, and the initialization program is a Guile
15803 program. That gives a lot of flexibility. The
15804 @code{expression->initrd} procedure builds such an initrd, given the
15805 program to run in that initrd.
15807 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15808 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15809 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15810 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15811 upon booting. All the derivations referenced by @var{exp} are
15812 automatically copied to the initrd.
15815 @node Bootloader Configuration
15816 @subsection Bootloader Configuration
15819 @cindex boot loader
15821 The operating system supports multiple bootloaders. The bootloader is
15822 configured using @code{bootloader-configuration} declaration. All the
15823 fields of this structure are bootloader agnostic except for one field,
15824 @code{bootloader} that indicates the bootloader to be configured and
15827 Some of the bootloaders do not honor every field of
15828 @code{bootloader-configuration}. For instance, the extlinux
15829 bootloader does not support themes and thus ignores the @code{theme}
15832 @deftp {Data Type} bootloader-configuration
15833 The type of a bootloader configuration declaration.
15837 @item @code{bootloader}
15838 @cindex EFI, bootloader
15839 @cindex UEFI, bootloader
15840 @cindex BIOS, bootloader
15841 The bootloader to use, as a @code{bootloader} object. For now
15842 @code{grub-bootloader}, @code{grub-efi-bootloader} and
15843 @code{extlinux-bootloader} are supported. @code{grub-efi-bootloader},
15844 allows to boot on modern systems using the @dfn{Unified Extensible
15845 Firmware Interface} (UEFI).
15847 Available bootloaders are described in @code{(gnu bootloader @dots{})}
15850 @item @code{device}
15851 This is a string denoting the boot device. It must be a device name
15852 understood by the bootloader @command{installer} command, such as
15853 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking grub-install,,, grub,
15856 @item @code{menu-entries} (default: @code{()})
15857 A possibly empty list of @code{menu-entry} objects (see below), denoting
15858 entries to appear in the bootloader menu, in addition to the current
15859 system entry and the entry pointing to previous system generations.
15862 @item @code{default-entry} (default: @code{0})
15863 The index of the default boot menu entry. Index 0 is for the entry of the
15866 @item @code{timeout} (default: @code{5})
15867 The number of seconds to wait for keyboard input before booting. Set to
15868 0 to boot immediately, and to -1 to wait indefinitely.
15870 @item @code{theme} (default: @var{#f})
15871 The bootloader theme object describing the theme to use. If no theme
15872 is provided, some bootloaders might use a default theme, that's true
15875 @item @code{terminal-outputs} (default: @code{'gfxterm})
15876 The output terminals used for the bootloader boot menu, as a list of
15877 symbols. GRUB accepts the values: @code{console}, @code{serial},
15878 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
15879 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
15880 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
15881 configuration,,, grub,GNU GRUB manual}).
15883 @item @code{terminal-inputs} (default: @code{'()})
15884 The input terminals used for the bootloader boot menu, as a list of
15885 symbols. For GRUB, the default is the native platform terminal as
15886 determined at run-time. GRUB accepts the values: @code{console},
15887 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
15888 @code{usb_keyboard}. This field corresponds to the GRUB variable
15889 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
15892 @item @code{serial-unit} (default: @code{#f})
15893 The serial unit used by the bootloader, as an integer from 0 to 3.
15894 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
15895 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15897 @item @code{serial-speed} (default: @code{#f})
15898 The speed of the serial interface, as an integer. For GRUB, the
15899 default value is chosen at run-time; currently GRUB chooses
15900 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15907 Should you want to list additional boot menu entries @i{via} the
15908 @code{menu-entries} field above, you will need to create them with the
15909 @code{menu-entry} form. For example, imagine you want to be able to
15910 boot another distro (hard to imagine!), you can define a menu entry
15915 (label "The Other Distro")
15916 (linux "/boot/old/vmlinux-2.6.32")
15917 (linux-arguments '("root=/dev/sda2"))
15918 (initrd "/boot/old/initrd"))
15923 @deftp {Data Type} menu-entry
15924 The type of an entry in the bootloader menu.
15929 The label to show in the menu---e.g., @code{"GNU"}.
15932 The Linux kernel image to boot, for example:
15935 (file-append linux-libre "/bzImage")
15938 For GRUB, it is also possible to specify a device explicitly in the
15939 file path using GRUB's device naming convention (@pxref{Naming
15940 convention,,, grub, GNU GRUB manual}), for example:
15943 "(hd0,msdos1)/boot/vmlinuz"
15946 If the device is specified explicitly as above, then the @code{device}
15947 field is ignored entirely.
15949 @item @code{linux-arguments} (default: @code{()})
15950 The list of extra Linux kernel command-line arguments---e.g.,
15951 @code{("console=ttyS0")}.
15953 @item @code{initrd}
15954 A G-Expression or string denoting the file name of the initial RAM disk
15955 to use (@pxref{G-Expressions}).
15956 @item @code{device} (default: @code{#f})
15957 The device where the kernel and initrd are to be found---i.e., for GRUB,
15958 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15960 This may be a file system label (a string), a file system UUID (a
15961 bytevector, @pxref{File Systems}), or @code{#f}, in which case
15962 the bootloader will search the device containing the file specified by
15963 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
15964 must @emph{not} be an OS device name such as @file{/dev/sda1}.
15969 @c FIXME: Write documentation once it's stable.
15970 Fow now only GRUB has theme support. GRUB themes are created using
15971 the @code{grub-theme} form, which is not documented yet.
15973 @defvr {Scheme Variable} %default-theme
15974 This is the default GRUB theme used by the operating system if no
15975 @code{theme} field is specified in @code{bootloader-configuration}
15978 It comes with a fancy background image displaying the GNU and Guix
15983 @node Invoking guix system
15984 @subsection Invoking @code{guix system}
15986 Once you have written an operating system declaration as seen in the
15987 previous section, it can be @dfn{instantiated} using the @command{guix
15988 system} command. The synopsis is:
15991 guix system @var{options}@dots{} @var{action} @var{file}
15994 @var{file} must be the name of a file containing an
15995 @code{operating-system} declaration. @var{action} specifies how the
15996 operating system is instantiated. Currently the following values are
16001 Build the operating system described in @var{file}, activate it, and
16002 switch to it@footnote{This action (and the related actions
16003 @code{switch-generation} and @code{roll-back}) are usable only on
16004 systems already running GuixSD.}.
16006 This effects all the configuration specified in @var{file}: user
16007 accounts, system services, global package list, setuid programs, etc.
16008 The command starts system services specified in @var{file} that are not
16009 currently running; if a service is currently running, it does not
16010 attempt to upgrade it since this would not be possible without stopping it
16013 This command creates a new generation whose number is one greater than
16014 the current generation (as reported by @command{guix system
16015 list-generations}). If that generation already exists, it will be
16016 overwritten. This behavior mirrors that of @command{guix package}
16017 (@pxref{Invoking guix package}).
16019 It also adds a bootloader menu entry for the new OS configuration,
16020 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
16021 entries for older configurations to a submenu, allowing you to choose
16022 an older system generation at boot time should you need it.
16025 @c The paragraph below refers to the problem discussed at
16026 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
16027 It is highly recommended to run @command{guix pull} once before you run
16028 @command{guix system reconfigure} for the first time (@pxref{Invoking
16029 guix pull}). Failing to do that you would see an older version of Guix
16030 once @command{reconfigure} has completed.
16033 @item switch-generation
16034 @cindex generations
16035 Switch to an existing system generation. This action atomically
16036 switches the system profile to the specified system generation. It
16037 also rearranges the system's existing bootloader menu entries. It
16038 makes the menu entry for the specified system generation the default,
16039 and it moves the entries for the other generatiors to a submenu, if
16040 supported by the bootloader being used. The next time the system
16041 boots, it will use the specified system generation.
16043 The bootloader itself is not being reinstalled when using this
16044 command. Thus, the installed bootloader is used with an updated
16045 configuration file.
16047 The target generation can be specified explicitly by its generation
16048 number. For example, the following invocation would switch to system
16052 guix system switch-generation 7
16055 The target generation can also be specified relative to the current
16056 generation with the form @code{+N} or @code{-N}, where @code{+3} means
16057 ``3 generations ahead of the current generation,'' and @code{-1} means
16058 ``1 generation prior to the current generation.'' When specifying a
16059 negative value such as @code{-1}, you must precede it with @code{--} to
16060 prevent it from being parsed as an option. For example:
16063 guix system switch-generation -- -1
16066 Currently, the effect of invoking this action is @emph{only} to switch
16067 the system profile to an existing generation and rearrange the
16068 bootloader menu entries. To actually start using the target system
16069 generation, you must reboot after running this action. In the future,
16070 it will be updated to do the same things as @command{reconfigure},
16071 like activating and deactivating services.
16073 This action will fail if the specified generation does not exist.
16076 @cindex rolling back
16077 Switch to the preceding system generation. The next time the system
16078 boots, it will use the preceding system generation. This is the inverse
16079 of @command{reconfigure}, and it is exactly the same as invoking
16080 @command{switch-generation} with an argument of @code{-1}.
16082 Currently, as with @command{switch-generation}, you must reboot after
16083 running this action to actually start using the preceding system
16087 Build the derivation of the operating system, which includes all the
16088 configuration files and programs needed to boot and run the system.
16089 This action does not actually install anything.
16092 Populate the given directory with all the files necessary to run the
16093 operating system specified in @var{file}. This is useful for first-time
16094 installations of GuixSD. For instance:
16097 guix system init my-os-config.scm /mnt
16100 copies to @file{/mnt} all the store items required by the configuration
16101 specified in @file{my-os-config.scm}. This includes configuration
16102 files, packages, and so on. It also creates other essential files
16103 needed for the system to operate correctly---e.g., the @file{/etc},
16104 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
16106 This command also installs bootloader on the device specified in
16107 @file{my-os-config}, unless the @option{--no-bootloader} option was
16111 @cindex virtual machine
16113 @anchor{guix system vm}
16114 Build a virtual machine that contains the operating system declared in
16115 @var{file}, and return a script to run that virtual machine (VM).
16116 Arguments given to the script are passed to QEMU.
16118 The VM shares its store with the host system.
16120 Additional file systems can be shared between the host and the VM using
16121 the @code{--share} and @code{--expose} command-line options: the former
16122 specifies a directory to be shared with write access, while the latter
16123 provides read-only access to the shared directory.
16125 The example below creates a VM in which the user's home directory is
16126 accessible read-only, and where the @file{/exchange} directory is a
16127 read-write mapping of @file{$HOME/tmp} on the host:
16130 guix system vm my-config.scm \
16131 --expose=$HOME --share=$HOME/tmp=/exchange
16134 On GNU/Linux, the default is to boot directly to the kernel; this has
16135 the advantage of requiring only a very tiny root disk image since the
16136 store of the host can then be mounted.
16138 The @code{--full-boot} option forces a complete boot sequence, starting
16139 with the bootloader. This requires more disk space since a root image
16140 containing at least the kernel, initrd, and bootloader data files must
16141 be created. The @code{--image-size} option can be used to specify the
16146 Return a virtual machine or disk image of the operating system declared
16147 in @var{file} that stands alone. Use the @option{--image-size} option
16148 to specify the size of the image.
16150 When using @code{vm-image}, the returned image is in qcow2 format, which
16151 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
16152 for more information on how to run the image in a virtual machine.
16154 When using @code{disk-image}, a raw disk image is produced; it can be
16155 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
16156 the device corresponding to a USB stick, one can copy the image to it
16157 using the following command:
16160 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
16164 Return a script to run the operating system declared in @var{file}
16165 within a container. Containers are a set of lightweight isolation
16166 mechanisms provided by the kernel Linux-libre. Containers are
16167 substantially less resource-demanding than full virtual machines since
16168 the kernel, shared objects, and other resources can be shared with the
16169 host system; this also means they provide thinner isolation.
16171 Currently, the script must be run as root in order to support more than
16172 a single user and group. The container shares its store with the host
16175 As with the @code{vm} action (@pxref{guix system vm}), additional file
16176 systems to be shared between the host and container can be specified
16177 using the @option{--share} and @option{--expose} options:
16180 guix system container my-config.scm \
16181 --expose=$HOME --share=$HOME/tmp=/exchange
16185 This option requires Linux-libre 3.19 or newer.
16190 @var{options} can contain any of the common build options (@pxref{Common
16191 Build Options}). In addition, @var{options} can contain one of the
16195 @item --system=@var{system}
16196 @itemx -s @var{system}
16197 Attempt to build for @var{system} instead of the host system type.
16198 This works as per @command{guix build} (@pxref{Invoking guix build}).
16202 Return the derivation file name of the given operating system without
16205 @item --image-size=@var{size}
16206 For the @code{vm-image} and @code{disk-image} actions, create an image
16207 of the given @var{size}. @var{size} may be a number of bytes, or it may
16208 include a unit as a suffix (@pxref{Block size, size specifications,,
16209 coreutils, GNU Coreutils}).
16211 @item --root=@var{file}
16212 @itemx -r @var{file}
16213 Make @var{file} a symlink to the result, and register it as a garbage
16216 @item --on-error=@var{strategy}
16217 Apply @var{strategy} when an error occurs when reading @var{file}.
16218 @var{strategy} may be one of the following:
16221 @item nothing-special
16222 Report the error concisely and exit. This is the default strategy.
16225 Likewise, but also display a backtrace.
16228 Report the error and enter Guile's debugger. From there, you can run
16229 commands such as @code{,bt} to get a backtrace, @code{,locals} to
16230 display local variable values, and more generally inspect the state of the
16231 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
16232 a list of available debugging commands.
16237 All the actions above, except @code{build} and @code{init},
16238 can use KVM support in the Linux-libre kernel. Specifically, if the
16239 machine has hardware virtualization support, the corresponding
16240 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
16241 must exist and be readable and writable by the user and by the
16242 build users of the daemon (@pxref{Build Environment Setup}).
16245 Once you have built, configured, re-configured, and re-re-configured
16246 your GuixSD installation, you may find it useful to list the operating
16247 system generations available on disk---and that you can choose from the
16248 bootloader boot menu:
16252 @item list-generations
16253 List a summary of each generation of the operating system available on
16254 disk, in a human-readable way. This is similar to the
16255 @option{--list-generations} option of @command{guix package}
16256 (@pxref{Invoking guix package}).
16258 Optionally, one can specify a pattern, with the same syntax that is used
16259 in @command{guix package --list-generations}, to restrict the list of
16260 generations displayed. For instance, the following command displays
16261 generations that are up to 10 days old:
16264 $ guix system list-generations 10d
16269 The @command{guix system} command has even more to offer! The following
16270 sub-commands allow you to visualize how your system services relate to
16273 @anchor{system-extension-graph}
16276 @item extension-graph
16277 Emit in Dot/Graphviz format to standard output the @dfn{service
16278 extension graph} of the operating system defined in @var{file}
16279 (@pxref{Service Composition}, for more information on service
16285 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
16288 produces a PDF file showing the extension relations among services.
16290 @anchor{system-shepherd-graph}
16291 @item shepherd-graph
16292 Emit in Dot/Graphviz format to standard output the @dfn{dependency
16293 graph} of shepherd services of the operating system defined in
16294 @var{file}. @xref{Shepherd Services}, for more information and for an
16299 @node Running GuixSD in a VM
16300 @subsection Running GuixSD in a Virtual Machine
16302 @cindex virtual machine
16303 To run GuixSD in a virtual machine (VM), one can either use the
16304 pre-built GuixSD VM image distributed at
16305 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
16306 , or build their own virtual machine image using @command{guix system
16307 vm-image} (@pxref{Invoking guix system}). The returned image is in
16308 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
16312 If you built your own image, you must copy it out of the store
16313 (@pxref{The Store}) and give yourself permission to write to the copy
16314 before you can use it. When invoking QEMU, you must choose a system
16315 emulator that is suitable for your hardware platform. Here is a minimal
16316 QEMU invocation that will boot the result of @command{guix system
16317 vm-image} on x86_64 hardware:
16320 $ qemu-system-x86_64 \
16321 -net user -net nic,model=virtio \
16322 -enable-kvm -m 256 /tmp/qemu-image
16325 Here is what each of these options means:
16328 @item qemu-system-x86_64
16329 This specifies the hardware platform to emulate. This should match the
16333 Enable the unprivileged user-mode network stack. The guest OS can
16334 access the host but not vice versa. This is the simplest way to get the
16337 @item -net nic,model=virtio
16338 You must create a network interface of a given model. If you do not
16339 create a NIC, the boot will fail. Assuming your hardware platform is
16340 x86_64, you can get a list of available NIC models by running
16341 @command{qemu-system-x86_64 -net nic,model=help}.
16344 If your system has hardware virtualization extensions, enabling the
16345 virtual machine support (KVM) of the Linux kernel will make things run
16349 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
16350 which may be insufficient for some operations.
16352 @item /tmp/qemu-image
16353 The file name of the qcow2 image.
16356 The default @command{run-vm.sh} script that is returned by an invocation of
16357 @command{guix system vm} does not add a @command{-net user} flag by default.
16358 To get network access from within the vm add the @code{(dhcp-client-service)}
16359 to your system definition and start the VM using
16360 @command{`guix system vm config.scm` -net user}. An important caveat of using
16361 @command{-net user} for networking is that @command{ping} will not work, because
16362 it uses the ICMP protocol. You'll have to use a different command to check for
16363 network connectivity, for example @command{guix download}.
16365 @subsubsection Connecting Through SSH
16369 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
16370 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
16371 boot unsupervised. It requires you to type some characters to initialize the
16372 randomness generator. In addition you need to forward the SSH port, 22 by
16373 default, to the host. You can do this with
16376 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
16379 To connect to the VM you can run
16382 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
16385 The @command{-p} tells @command{ssh} the port you want to connect to.
16386 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
16387 every time you modify your @command{config.scm} file and the
16388 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
16389 connection to an unknown host every time you connect.
16391 @subsubsection Using @command{virt-viewer} with Spice
16393 As an alternative to the default @command{qemu} graphical client you can
16394 use the @command{remote-viewer} from the @command{virt-viewer} package. To
16395 connect pass the @command{-spice port=5930,disable-ticketing} flag to
16396 @command{qemu}. See previous section for further information on how to do this.
16398 Spice also allows you to do some nice stuff like share your clipboard with your
16399 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
16402 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
16403 -chardev spicevmc,name=vdagent,id=vdagent
16404 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
16405 name=com.redhat.spice.0
16408 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
16410 @node Defining Services
16411 @subsection Defining Services
16413 The previous sections show the available services and how one can combine
16414 them in an @code{operating-system} declaration. But how do we define
16415 them in the first place? And what is a service anyway?
16418 * Service Composition:: The model for composing services.
16419 * Service Types and Services:: Types and services.
16420 * Service Reference:: API reference.
16421 * Shepherd Services:: A particular type of service.
16424 @node Service Composition
16425 @subsubsection Service Composition
16429 Here we define a @dfn{service} as, broadly, something that extends the
16430 functionality of the operating system. Often a service is a process---a
16431 @dfn{daemon}---started when the system boots: a secure shell server, a
16432 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
16433 whose execution can be triggered by another daemon---e.g., an FTP server
16434 started by @command{inetd} or a D-Bus service activated by
16435 @command{dbus-daemon}. Occasionally, a service does not map to a
16436 daemon. For instance, the ``account'' service collects user accounts
16437 and makes sure they exist when the system runs; the ``udev'' service
16438 collects device management rules and makes them available to the eudev
16439 daemon; the @file{/etc} service populates the @file{/etc} directory
16442 @cindex service extensions
16443 GuixSD services are connected by @dfn{extensions}. For instance, the
16444 secure shell service @emph{extends} the Shepherd---the GuixSD
16445 initialization system, running as PID@tie{}1---by giving it the command
16446 lines to start and stop the secure shell daemon (@pxref{Networking
16447 Services, @code{lsh-service}}); the UPower service extends the D-Bus
16448 service by passing it its @file{.service} specification, and extends the
16449 udev service by passing it device management rules (@pxref{Desktop
16450 Services, @code{upower-service}}); the Guix daemon service extends the
16451 Shepherd by passing it the command lines to start and stop the daemon,
16452 and extends the account service by passing it a list of required build
16453 user accounts (@pxref{Base Services}).
16455 All in all, services and their ``extends'' relations form a directed
16456 acyclic graph (DAG). If we represent services as boxes and extensions
16457 as arrows, a typical system might provide something like this:
16459 @image{images/service-graph,,5in,Typical service extension graph.}
16461 @cindex system service
16462 At the bottom, we see the @dfn{system service}, which produces the
16463 directory containing everything to run and boot the system, as returned
16464 by the @command{guix system build} command. @xref{Service Reference},
16465 to learn about the other service types shown here.
16466 @xref{system-extension-graph, the @command{guix system extension-graph}
16467 command}, for information on how to generate this representation for a
16468 particular operating system definition.
16470 @cindex service types
16471 Technically, developers can define @dfn{service types} to express these
16472 relations. There can be any number of services of a given type on the
16473 system---for instance, a system running two instances of the GNU secure
16474 shell server (lsh) has two instances of @var{lsh-service-type}, with
16475 different parameters.
16477 The following section describes the programming interface for service
16478 types and services.
16480 @node Service Types and Services
16481 @subsubsection Service Types and Services
16483 A @dfn{service type} is a node in the DAG described above. Let us start
16484 with a simple example, the service type for the Guix build daemon
16485 (@pxref{Invoking guix-daemon}):
16488 (define guix-service-type
16492 (list (service-extension shepherd-root-service-type guix-shepherd-service)
16493 (service-extension account-service-type guix-accounts)
16494 (service-extension activation-service-type guix-activation)))
16495 (default-value (guix-configuration))))
16499 It defines three things:
16503 A name, whose sole purpose is to make inspection and debugging easier.
16506 A list of @dfn{service extensions}, where each extension designates the
16507 target service type and a procedure that, given the parameters of the
16508 service, returns a list of objects to extend the service of that type.
16510 Every service type has at least one service extension. The only
16511 exception is the @dfn{boot service type}, which is the ultimate service.
16514 Optionally, a default value for instances of this type.
16517 In this example, @var{guix-service-type} extends three services:
16520 @item shepherd-root-service-type
16521 The @var{guix-shepherd-service} procedure defines how the Shepherd
16522 service is extended. Namely, it returns a @code{<shepherd-service>}
16523 object that defines how @command{guix-daemon} is started and stopped
16524 (@pxref{Shepherd Services}).
16526 @item account-service-type
16527 This extension for this service is computed by @var{guix-accounts},
16528 which returns a list of @code{user-group} and @code{user-account}
16529 objects representing the build user accounts (@pxref{Invoking
16532 @item activation-service-type
16533 Here @var{guix-activation} is a procedure that returns a gexp, which is
16534 a code snippet to run at ``activation time''---e.g., when the service is
16538 A service of this type is instantiated like this:
16541 (service guix-service-type
16542 (guix-configuration
16544 (use-substitutes? #f)))
16547 The second argument to the @code{service} form is a value representing
16548 the parameters of this specific service instance.
16549 @xref{guix-configuration-type, @code{guix-configuration}}, for
16550 information about the @code{guix-configuration} data type. When the
16551 value is omitted, the default value specified by
16552 @code{guix-service-type} is used:
16555 (service guix-service-type)
16558 @var{guix-service-type} is quite simple because it extends other
16559 services but is not extensible itself.
16561 @c @subsubsubsection Extensible Service Types
16563 The service type for an @emph{extensible} service looks like this:
16566 (define udev-service-type
16567 (service-type (name 'udev)
16569 (list (service-extension shepherd-root-service-type
16570 udev-shepherd-service)))
16572 (compose concatenate) ;concatenate the list of rules
16573 (extend (lambda (config rules)
16575 (($ <udev-configuration> udev initial-rules)
16576 (udev-configuration
16577 (udev udev) ;the udev package to use
16578 (rules (append initial-rules rules)))))))))
16581 This is the service type for the
16582 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
16583 management daemon}. Compared to the previous example, in addition to an
16584 extension of @var{shepherd-root-service-type}, we see two new fields:
16588 This is the procedure to @dfn{compose} the list of extensions to
16589 services of this type.
16591 Services can extend the udev service by passing it lists of rules; we
16592 compose those extensions simply by concatenating them.
16595 This procedure defines how the value of the service is @dfn{extended} with
16596 the composition of the extensions.
16598 Udev extensions are composed into a list of rules, but the udev service
16599 value is itself a @code{<udev-configuration>} record. So here, we
16600 extend that record by appending the list of rules it contains to the
16601 list of contributed rules.
16604 There can be only one instance of an extensible service type such as
16605 @var{udev-service-type}. If there were more, the
16606 @code{service-extension} specifications would be ambiguous.
16608 Still here? The next section provides a reference of the programming
16609 interface for services.
16611 @node Service Reference
16612 @subsubsection Service Reference
16614 We have seen an overview of service types (@pxref{Service Types and
16615 Services}). This section provides a reference on how to manipulate
16616 services and service types. This interface is provided by the
16617 @code{(gnu services)} module.
16619 @deffn {Scheme Procedure} service @var{type} [@var{value}]
16620 Return a new service of @var{type}, a @code{<service-type>} object (see
16621 below.) @var{value} can be any object; it represents the parameters of
16622 this particular service instance.
16624 When @var{value} is omitted, the default value specified by @var{type}
16625 is used; if @var{type} does not specify a default value, an error is
16628 For instance, this:
16631 (service openssh-service-type)
16635 is equivalent to this:
16638 (service openssh-service-type
16639 (openssh-configuration))
16642 In both cases the result is an instance of @code{openssh-service-type}
16643 with the default configuration.
16646 @deffn {Scheme Procedure} service? @var{obj}
16647 Return true if @var{obj} is a service.
16650 @deffn {Scheme Procedure} service-kind @var{service}
16651 Return the type of @var{service}---i.e., a @code{<service-type>} object.
16654 @deffn {Scheme Procedure} service-value @var{service}
16655 Return the value associated with @var{service}. It represents its
16659 Here is an example of how a service is created and manipulated:
16663 (service nginx-service-type
16664 (nginx-configuration
16666 (log-directory log-directory)
16667 (run-directory run-directory)
16668 (file config-file))))
16673 (eq? (service-kind s) nginx-service-type)
16677 The @code{modify-services} form provides a handy way to change the
16678 parameters of some of the services of a list such as
16679 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
16680 evaluates to a list of services. Of course, you could always use
16681 standard list combinators such as @code{map} and @code{fold} to do that
16682 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
16683 @code{modify-services} simply provides a more concise form for this
16686 @deffn {Scheme Syntax} modify-services @var{services} @
16687 (@var{type} @var{variable} => @var{body}) @dots{}
16689 Modify the services listed in @var{services} according to the given
16690 clauses. Each clause has the form:
16693 (@var{type} @var{variable} => @var{body})
16696 where @var{type} is a service type---e.g.,
16697 @code{guix-service-type}---and @var{variable} is an identifier that is
16698 bound within the @var{body} to the service parameters---e.g., a
16699 @code{guix-configuration} instance---of the original service of that
16702 The @var{body} should evaluate to the new service parameters, which will
16703 be used to configure the new service. This new service will replace the
16704 original in the resulting list. Because a service's service parameters
16705 are created using @code{define-record-type*}, you can write a succinct
16706 @var{body} that evaluates to the new service parameters by using the
16707 @code{inherit} feature that @code{define-record-type*} provides.
16709 @xref{Using the Configuration System}, for example usage.
16713 Next comes the programming interface for service types. This is
16714 something you want to know when writing new service definitions, but not
16715 necessarily when simply looking for ways to customize your
16716 @code{operating-system} declaration.
16718 @deftp {Data Type} service-type
16719 @cindex service type
16720 This is the representation of a @dfn{service type} (@pxref{Service Types
16725 This is a symbol, used only to simplify inspection and debugging.
16727 @item @code{extensions}
16728 A non-empty list of @code{<service-extension>} objects (see below).
16730 @item @code{compose} (default: @code{#f})
16731 If this is @code{#f}, then the service type denotes services that cannot
16732 be extended---i.e., services that do not receive ``values'' from other
16735 Otherwise, it must be a one-argument procedure. The procedure is called
16736 by @code{fold-services} and is passed a list of values collected from
16737 extensions. It must return a value that is a valid parameter value for
16738 the service instance.
16740 @item @code{extend} (default: @code{#f})
16741 If this is @code{#f}, services of this type cannot be extended.
16743 Otherwise, it must be a two-argument procedure: @code{fold-services}
16744 calls it, passing it the initial value of the service as the first argument
16745 and the result of applying @code{compose} to the extension values as the
16749 @xref{Service Types and Services}, for examples.
16752 @deffn {Scheme Procedure} service-extension @var{target-type} @
16754 Return a new extension for services of type @var{target-type}.
16755 @var{compute} must be a one-argument procedure: @code{fold-services}
16756 calls it, passing it the value associated with the service that provides
16757 the extension; it must return a valid value for the target service.
16760 @deffn {Scheme Procedure} service-extension? @var{obj}
16761 Return true if @var{obj} is a service extension.
16764 Occasionally, you might want to simply extend an existing service. This
16765 involves creating a new service type and specifying the extension of
16766 interest, which can be verbose; the @code{simple-service} procedure
16767 provides a shorthand for this.
16769 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16770 Return a service that extends @var{target} with @var{value}. This works
16771 by creating a singleton service type @var{name}, of which the returned
16772 service is an instance.
16774 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16778 (simple-service 'my-mcron-job mcron-service-type
16779 #~(job '(next-hour (3)) "guix gc -F 2G"))
16783 At the core of the service abstraction lies the @code{fold-services}
16784 procedure, which is responsible for ``compiling'' a list of services
16785 down to a single directory that contains everything needed to boot and
16786 run the system---the directory shown by the @command{guix system build}
16787 command (@pxref{Invoking guix system}). In essence, it propagates
16788 service extensions down the service graph, updating each node parameters
16789 on the way, until it reaches the root node.
16791 @deffn {Scheme Procedure} fold-services @var{services} @
16792 [#:target-type @var{system-service-type}]
16793 Fold @var{services} by propagating their extensions down to the root of
16794 type @var{target-type}; return the root service adjusted accordingly.
16797 Lastly, the @code{(gnu services)} module also defines several essential
16798 service types, some of which are listed below.
16800 @defvr {Scheme Variable} system-service-type
16801 This is the root of the service graph. It produces the system directory
16802 as returned by the @command{guix system build} command.
16805 @defvr {Scheme Variable} boot-service-type
16806 The type of the ``boot service'', which produces the @dfn{boot script}.
16807 The boot script is what the initial RAM disk runs when booting.
16810 @defvr {Scheme Variable} etc-service-type
16811 The type of the @file{/etc} service. This service can be extended by
16812 passing it name/file tuples such as:
16815 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16818 In this example, the effect would be to add an @file{/etc/issue} file
16819 pointing to the given file.
16822 @defvr {Scheme Variable} setuid-program-service-type
16823 Type for the ``setuid-program service''. This service collects lists of
16824 executable file names, passed as gexps, and adds them to the set of
16825 setuid-root programs on the system (@pxref{Setuid Programs}).
16828 @defvr {Scheme Variable} profile-service-type
16829 Type of the service that populates the @dfn{system profile}---i.e., the
16830 programs under @file{/run/current-system/profile}. Other services can
16831 extend it by passing it lists of packages to add to the system profile.
16835 @node Shepherd Services
16836 @subsubsection Shepherd Services
16838 @cindex shepherd services
16840 @cindex init system
16841 The @code{(gnu services shepherd)} module provides a way to define
16842 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16843 initialization system---the first process that is started when the
16844 system boots, also known as PID@tie{}1
16845 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16847 Services in the Shepherd can depend on each other. For instance, the
16848 SSH daemon may need to be started after the syslog daemon has been
16849 started, which in turn can only happen once all the file systems have
16850 been mounted. The simple operating system defined earlier (@pxref{Using
16851 the Configuration System}) results in a service graph like this:
16853 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16855 You can actually generate such a graph for any operating system
16856 definition using the @command{guix system shepherd-graph} command
16857 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16859 The @var{%shepherd-root-service} is a service object representing
16860 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16861 by passing it lists of @code{<shepherd-service>} objects.
16863 @deftp {Data Type} shepherd-service
16864 The data type representing a service managed by the Shepherd.
16867 @item @code{provision}
16868 This is a list of symbols denoting what the service provides.
16870 These are the names that may be passed to @command{herd start},
16871 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16872 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16873 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16875 @item @code{requirements} (default: @code{'()})
16876 List of symbols denoting the Shepherd services this one depends on.
16878 @item @code{respawn?} (default: @code{#t})
16879 Whether to restart the service when it stops, for instance when the
16880 underlying process dies.
16883 @itemx @code{stop} (default: @code{#~(const #f)})
16884 The @code{start} and @code{stop} fields refer to the Shepherd's
16885 facilities to start and stop processes (@pxref{Service De- and
16886 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16887 G-expressions that get expanded in the Shepherd configuration file
16888 (@pxref{G-Expressions}).
16890 @item @code{documentation}
16891 A documentation string, as shown when running:
16894 herd doc @var{service-name}
16897 where @var{service-name} is one of the symbols in @var{provision}
16898 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16900 @item @code{modules} (default: @var{%default-modules})
16901 This is the list of modules that must be in scope when @code{start} and
16902 @code{stop} are evaluated.
16907 @defvr {Scheme Variable} shepherd-root-service-type
16908 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16910 This is the service type that extensions target when they want to create
16911 shepherd services (@pxref{Service Types and Services}, for an example).
16912 Each extension must pass a list of @code{<shepherd-service>}.
16915 @defvr {Scheme Variable} %shepherd-root-service
16916 This service represents PID@tie{}1.
16920 @node Documentation
16921 @section Documentation
16923 @cindex documentation, searching for
16924 @cindex searching for documentation
16925 @cindex Info, documentation format
16927 @cindex manual pages
16928 In most cases packages installed with Guix come with documentation.
16929 There are two main documentation formats: ``Info'', a browseable
16930 hypertext format used for GNU software, and ``manual pages'' (or ``man
16931 pages''), the linear documentation format traditionally found on Unix.
16932 Info manuals are accessed with the @command{info} command or with Emacs,
16933 and man pages are accessed using @command{man}.
16935 You can look for documentation of software installed on your system by
16936 keyword. For example, the following command searches for information
16937 about ``TLS'' in Info manuals:
16941 "(emacs)Network Security" -- STARTTLS
16942 "(emacs)Network Security" -- TLS
16943 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16944 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16949 The command below searches for the same keyword in man pages:
16953 SSL (7) - OpenSSL SSL/TLS library
16954 certtool (1) - GnuTLS certificate tool
16958 These searches are purely local to your computer so you have the
16959 guarantee that documentation you find corresponds to what you have
16960 actually installed, you can access it off-line, and your privacy is
16963 Once you have these results, you can view the relevant documentation by
16967 $ info "(gnutls)Core TLS API"
16977 Info manuals contain sections and indices as well as hyperlinks like
16978 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16979 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16980 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16981 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16982 Introduction}, for an introduction to Info navigation.
16984 @node Installing Debugging Files
16985 @section Installing Debugging Files
16987 @cindex debugging files
16988 Program binaries, as produced by the GCC compilers for instance, are
16989 typically written in the ELF format, with a section containing
16990 @dfn{debugging information}. Debugging information is what allows the
16991 debugger, GDB, to map binary code to source code; it is required to
16992 debug a compiled program in good conditions.
16994 The problem with debugging information is that is takes up a fair amount
16995 of disk space. For example, debugging information for the GNU C Library
16996 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16997 debugging info of all the installed programs is usually not an option.
16998 Yet, space savings should not come at the cost of an impediment to
16999 debugging---especially in the GNU system, which should make it easier
17000 for users to exert their computing freedom (@pxref{GNU Distribution}).
17002 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
17003 mechanism that allows users to get the best of both worlds: debugging
17004 information can be stripped from the binaries and stored in separate
17005 files. GDB is then able to load debugging information from those files,
17006 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
17009 The GNU distribution takes advantage of this by storing debugging
17010 information in the @code{lib/debug} sub-directory of a separate package
17011 output unimaginatively called @code{debug} (@pxref{Packages with
17012 Multiple Outputs}). Users can choose to install the @code{debug} output
17013 of a package when they need it. For instance, the following command
17014 installs the debugging information for the GNU C Library and for GNU
17018 guix package -i glibc:debug guile:debug
17021 GDB must then be told to look for debug files in the user's profile, by
17022 setting the @code{debug-file-directory} variable (consider setting it
17023 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
17027 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
17030 From there on, GDB will pick up debugging information from the
17031 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
17033 In addition, you will most likely want GDB to be able to show the source
17034 code being debugged. To do that, you will have to unpack the source
17035 code of the package of interest (obtained with @code{guix build
17036 --source}, @pxref{Invoking guix build}), and to point GDB to that source
17037 directory using the @code{directory} command (@pxref{Source Path,
17038 @code{directory},, gdb, Debugging with GDB}).
17040 @c XXX: keep me up-to-date
17041 The @code{debug} output mechanism in Guix is implemented by the
17042 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
17043 opt-in---debugging information is available only for the packages
17044 with definitions explicitly declaring a @code{debug} output. This may be
17045 changed to opt-out in the future if our build farm servers can handle
17046 the load. To check whether a package has a @code{debug} output, use
17047 @command{guix package --list-available} (@pxref{Invoking guix package}).
17050 @node Security Updates
17051 @section Security Updates
17053 @cindex security updates
17054 @cindex security vulnerabilities
17055 Occasionally, important security vulnerabilities are discovered in software
17056 packages and must be patched. Guix developers try hard to keep track of
17057 known vulnerabilities and to apply fixes as soon as possible in the
17058 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
17059 containing only security updates.) The @command{guix lint} tool helps
17060 developers find out about vulnerable versions of software packages in the
17065 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
17066 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
17067 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
17071 @xref{Invoking guix lint}, for more information.
17074 As of version @value{VERSION}, the feature described below is considered
17078 Guix follows a functional
17079 package management discipline (@pxref{Introduction}), which implies
17080 that, when a package is changed, @emph{every package that depends on it}
17081 must be rebuilt. This can significantly slow down the deployment of
17082 fixes in core packages such as libc or Bash, since basically the whole
17083 distribution would need to be rebuilt. Using pre-built binaries helps
17084 (@pxref{Substitutes}), but deployment may still take more time than
17088 To address this, Guix implements @dfn{grafts}, a mechanism that allows
17089 for fast deployment of critical updates without the costs associated
17090 with a whole-distribution rebuild. The idea is to rebuild only the
17091 package that needs to be patched, and then to ``graft'' it onto packages
17092 explicitly installed by the user and that were previously referring to
17093 the original package. The cost of grafting is typically very low, and
17094 order of magnitudes lower than a full rebuild of the dependency chain.
17096 @cindex replacements of packages, for grafts
17097 For instance, suppose a security update needs to be applied to Bash.
17098 Guix developers will provide a package definition for the ``fixed''
17099 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
17100 Packages}). Then, the original package definition is augmented with a
17101 @code{replacement} field pointing to the package containing the bug fix:
17108 (replacement bash-fixed)))
17111 From there on, any package depending directly or indirectly on Bash---as
17112 reported by @command{guix gc --requisites} (@pxref{Invoking guix
17113 gc})---that is installed is automatically ``rewritten'' to refer to
17114 @var{bash-fixed} instead of @var{bash}. This grafting process takes
17115 time proportional to the size of the package, usually less than a
17116 minute for an ``average'' package on a recent machine. Grafting is
17117 recursive: when an indirect dependency requires grafting, then grafting
17118 ``propagates'' up to the package that the user is installing.
17120 Currently, the length of the name and version of the graft and that of
17121 the package it replaces (@var{bash-fixed} and @var{bash} in the example
17122 above) must be equal. This restriction mostly comes from the fact that
17123 grafting works by patching files, including binary files, directly.
17124 Other restrictions may apply: for instance, when adding a graft to a
17125 package providing a shared library, the original shared library and its
17126 replacement must have the same @code{SONAME} and be binary-compatible.
17128 The @option{--no-grafts} command-line option allows you to forcefully
17129 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
17133 guix build bash --no-grafts
17137 returns the store file name of the original Bash, whereas:
17144 returns the store file name of the ``fixed'', replacement Bash. This
17145 allows you to distinguish between the two variants of Bash.
17147 To verify which Bash your whole profile refers to, you can run
17148 (@pxref{Invoking guix gc}):
17151 guix gc -R `readlink -f ~/.guix-profile` | grep bash
17155 @dots{} and compare the store file names that you get with those above.
17156 Likewise for a complete GuixSD system generation:
17159 guix gc -R `guix system build my-config.scm` | grep bash
17162 Lastly, to check which Bash running processes are using, you can use the
17163 @command{lsof} command:
17166 lsof | grep /gnu/store/.*bash
17170 @node Package Modules
17171 @section Package Modules
17173 From a programming viewpoint, the package definitions of the
17174 GNU distribution are provided by Guile modules in the @code{(gnu packages
17175 @dots{})} name space@footnote{Note that packages under the @code{(gnu
17176 packages @dots{})} module name space are not necessarily ``GNU
17177 packages''. This module naming scheme follows the usual Guile module
17178 naming convention: @code{gnu} means that these modules are distributed
17179 as part of the GNU system, and @code{packages} identifies modules that
17180 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
17181 Reference Manual}). For instance, the @code{(gnu packages emacs)}
17182 module exports a variable named @code{emacs}, which is bound to a
17183 @code{<package>} object (@pxref{Defining Packages}).
17185 The @code{(gnu packages @dots{})} module name space is
17186 automatically scanned for packages by the command-line tools. For
17187 instance, when running @code{guix package -i emacs}, all the @code{(gnu
17188 packages @dots{})} modules are scanned until one that exports a package
17189 object whose name is @code{emacs} is found. This package search
17190 facility is implemented in the @code{(gnu packages)} module.
17192 @cindex customization, of packages
17193 @cindex package module search path
17194 Users can store package definitions in modules with different
17195 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
17196 name and module name must match. For instance, the @code{(my-packages
17197 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
17198 relative to the load path specified with @option{--load-path} or
17199 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
17200 guile, GNU Guile Reference Manual}, for details.}. These package definitions
17201 will not be visible by default. Users can invoke commands such as
17202 @command{guix package} and @command{guix build} with the
17203 @code{-e} option so that they know where to find the package. Better
17204 yet, they can use the
17205 @code{-L} option of these commands to make those modules visible
17206 (@pxref{Invoking guix build, @code{--load-path}}), or define the
17207 @code{GUIX_PACKAGE_PATH} environment variable. This environment
17208 variable makes it easy to extend or customize the distribution and is
17209 honored by all the user interfaces.
17211 @defvr {Environment Variable} GUIX_PACKAGE_PATH
17212 This is a colon-separated list of directories to search for additional
17213 package modules. Directories listed in this variable take precedence
17214 over the own modules of the distribution.
17217 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
17218 each package is built based solely on other packages in the
17219 distribution. The root of this dependency graph is a small set of
17220 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
17221 bootstrap)} module. For more information on bootstrapping,
17222 @pxref{Bootstrapping}.
17224 @node Packaging Guidelines
17225 @section Packaging Guidelines
17227 @cindex packages, creating
17228 The GNU distribution is nascent and may well lack some of your favorite
17229 packages. This section describes how you can help make the distribution
17230 grow. @xref{Contributing}, for additional information on how you can
17233 Free software packages are usually distributed in the form of
17234 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
17235 all the source files. Adding a package to the distribution means
17236 essentially two things: adding a @dfn{recipe} that describes how to
17237 build the package, including a list of other packages required to build
17238 it, and adding @dfn{package metadata} along with that recipe, such as a
17239 description and licensing information.
17241 In Guix all this information is embodied in @dfn{package definitions}.
17242 Package definitions provide a high-level view of the package. They are
17243 written using the syntax of the Scheme programming language; in fact,
17244 for each package we define a variable bound to the package definition,
17245 and export that variable from a module (@pxref{Package Modules}).
17246 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
17247 creating packages. For more information on package definitions,
17248 @pxref{Defining Packages}.
17250 Once a package definition is in place, stored in a file in the Guix
17251 source tree, it can be tested using the @command{guix build} command
17252 (@pxref{Invoking guix build}). For example, assuming the new package is
17253 called @code{gnew}, you may run this command from the Guix build tree
17254 (@pxref{Running Guix Before It Is Installed}):
17257 ./pre-inst-env guix build gnew --keep-failed
17260 Using @code{--keep-failed} makes it easier to debug build failures since
17261 it provides access to the failed build tree. Another useful
17262 command-line option when debugging is @code{--log-file}, to access the
17265 If the package is unknown to the @command{guix} command, it may be that
17266 the source file contains a syntax error, or lacks a @code{define-public}
17267 clause to export the package variable. To figure it out, you may load
17268 the module from Guile to get more information about the actual error:
17271 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
17274 Once your package builds correctly, please send us a patch
17275 (@pxref{Contributing}). Well, if you need help, we will be happy to
17276 help you too. Once the patch is committed in the Guix repository, the
17277 new package automatically gets built on the supported platforms by
17278 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
17281 @cindex substituter
17282 Users can obtain the new package definition simply by running
17283 @command{guix pull} (@pxref{Invoking guix pull}). When
17284 @code{hydra.gnu.org} is done building the package, installing the
17285 package automatically downloads binaries from there
17286 (@pxref{Substitutes}). The only place where human intervention is
17287 needed is to review and apply the patch.
17291 * Software Freedom:: What may go into the distribution.
17292 * Package Naming:: What's in a name?
17293 * Version Numbers:: When the name is not enough.
17294 * Synopses and Descriptions:: Helping users find the right package.
17295 * Python Modules:: A touch of British comedy.
17296 * Perl Modules:: Little pearls.
17297 * Java Packages:: Coffee break.
17298 * Fonts:: Fond of fonts.
17301 @node Software Freedom
17302 @subsection Software Freedom
17304 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
17305 @cindex free software
17306 The GNU operating system has been developed so that users can have
17307 freedom in their computing. GNU is @dfn{free software}, meaning that
17308 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
17309 essential freedoms}: to run the program, to study and change the program
17310 in source code form, to redistribute exact copies, and to distribute
17311 modified versions. Packages found in the GNU distribution provide only
17312 software that conveys these four freedoms.
17314 In addition, the GNU distribution follow the
17315 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
17316 software distribution guidelines}. Among other things, these guidelines
17317 reject non-free firmware, recommendations of non-free software, and
17318 discuss ways to deal with trademarks and patents.
17320 Some otherwise free upstream package sources contain a small and optional
17321 subset that violates the above guidelines, for instance because this subset
17322 is itself non-free code. When that happens, the offending items are removed
17323 with appropriate patches or code snippets in the @code{origin} form of the
17324 package (@pxref{Defining Packages}). This way, @code{guix
17325 build --source} returns the ``freed'' source rather than the unmodified
17329 @node Package Naming
17330 @subsection Package Naming
17332 @cindex package name
17333 A package has actually two names associated with it:
17334 First, there is the name of the @emph{Scheme variable}, the one following
17335 @code{define-public}. By this name, the package can be made known in the
17336 Scheme code, for instance as input to another package. Second, there is
17337 the string in the @code{name} field of a package definition. This name
17338 is used by package management commands such as
17339 @command{guix package} and @command{guix build}.
17341 Both are usually the same and correspond to the lowercase conversion of
17342 the project name chosen upstream, with underscores replaced with
17343 hyphens. For instance, GNUnet is available as @code{gnunet}, and
17344 SDL_net as @code{sdl-net}.
17346 We do not add @code{lib} prefixes for library packages, unless these are
17347 already part of the official project name. But @pxref{Python
17348 Modules} and @ref{Perl Modules} for special rules concerning modules for
17349 the Python and Perl languages.
17351 Font package names are handled differently, @pxref{Fonts}.
17354 @node Version Numbers
17355 @subsection Version Numbers
17357 @cindex package version
17358 We usually package only the latest version of a given free software
17359 project. But sometimes, for instance for incompatible library versions,
17360 two (or more) versions of the same package are needed. These require
17361 different Scheme variable names. We use the name as defined
17362 in @ref{Package Naming}
17363 for the most recent version; previous versions use the same name, suffixed
17364 by @code{-} and the smallest prefix of the version number that may
17365 distinguish the two versions.
17367 The name inside the package definition is the same for all versions of a
17368 package and does not contain any version number.
17370 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
17373 (define-public gtk+
17378 (define-public gtk+-2
17381 (version "2.24.20")
17384 If we also wanted GTK+ 3.8.2, this would be packaged as
17386 (define-public gtk+-3.8
17393 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
17394 @c for a discussion of what follows.
17395 @cindex version number, for VCS snapshots
17396 Occasionally, we package snapshots of upstream's version control system
17397 (VCS) instead of formal releases. This should remain exceptional,
17398 because it is up to upstream developers to clarify what the stable
17399 release is. Yet, it is sometimes necessary. So, what should we put in
17400 the @code{version} field?
17402 Clearly, we need to make the commit identifier of the VCS snapshot
17403 visible in the version string, but we also need to make sure that the
17404 version string is monotonically increasing so that @command{guix package
17405 --upgrade} can determine which version is newer. Since commit
17406 identifiers, notably with Git, are not monotonically increasing, we add
17407 a revision number that we increase each time we upgrade to a newer
17408 snapshot. The resulting version string looks like this:
17413 | | `-- upstream commit ID
17415 | `--- Guix package revision
17417 latest upstream version
17420 It is a good idea to strip commit identifiers in the @code{version}
17421 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
17422 aesthetics have a role to play here) as well as problems related to OS
17423 limits such as the maximum shebang length (127 bytes for the Linux
17424 kernel.) It is best to use the full commit identifiers in
17425 @code{origin}s, though, to avoid ambiguities. A typical package
17426 definition may look like this:
17430 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
17431 (revision "1")) ;Guix package revision
17433 (version (string-append "0.9-" revision "."
17434 (string-take commit 7)))
17437 (uri (git-reference
17438 (url "git://example.org/my-package.git")
17440 (sha256 (base32 "1mbikn@dots{}"))
17441 (file-name (string-append "my-package-" version
17447 @node Synopses and Descriptions
17448 @subsection Synopses and Descriptions
17450 @cindex package description
17451 @cindex package synopsis
17452 As we have seen before, each package in GNU@tie{}Guix includes a
17453 synopsis and a description (@pxref{Defining Packages}). Synopses and
17454 descriptions are important: They are what @command{guix package
17455 --search} searches, and a crucial piece of information to help users
17456 determine whether a given package suits their needs. Consequently,
17457 packagers should pay attention to what goes into them.
17459 Synopses must start with a capital letter and must not end with a
17460 period. They must not start with ``a'' or ``the'', which usually does
17461 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
17462 tool that frobs files''. The synopsis should say what the package
17463 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
17464 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
17465 matching a pattern''.
17467 Keep in mind that the synopsis must be meaningful for a very wide
17468 audience. For example, ``Manipulate alignments in the SAM format''
17469 might make sense for a seasoned bioinformatics researcher, but might be
17470 fairly unhelpful or even misleading to a non-specialized audience. It
17471 is a good idea to come up with a synopsis that gives an idea of the
17472 application domain of the package. In this example, this might give
17473 something like ``Manipulate nucleotide sequence alignments'', which
17474 hopefully gives the user a better idea of whether this is what they are
17477 Descriptions should take between five and ten lines. Use full
17478 sentences, and avoid using acronyms without first introducing them.
17479 Please avoid marketing phrases such as ``world-leading'',
17480 ``industrial-strength'', and ``next-generation'', and avoid superlatives
17481 like ``the most advanced''---they are not helpful to users looking for a
17482 package and may even sound suspicious. Instead, try to be factual,
17483 mentioning use cases and features.
17485 @cindex Texinfo markup, in package descriptions
17486 Descriptions can include Texinfo markup, which is useful to introduce
17487 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
17488 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
17489 should be careful when using some characters for example @samp{@@} and
17490 curly braces which are the basic special characters in Texinfo
17491 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
17492 such as @command{guix package --show} take care of rendering it
17495 Synopses and descriptions are translated by volunteers
17496 @uref{http://translationproject.org/domain/guix-packages.html, at the
17497 Translation Project} so that as many users as possible can read them in
17498 their native language. User interfaces search them and display them in
17499 the language specified by the current locale.
17501 Translation is a lot of work so, as a packager, please pay even more
17502 attention to your synopses and descriptions as every change may entail
17503 additional work for translators. In order to help them, it is possible
17504 to make recommendations or instructions visible to them by inserting
17505 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
17509 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
17510 (description "ARandR is designed to provide a simple visual front end
17511 for the X11 resize-and-rotate (RandR) extension. @dots{}")
17515 @node Python Modules
17516 @subsection Python Modules
17519 We currently package Python 2 and Python 3, under the Scheme variable names
17520 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
17521 To avoid confusion and naming clashes with other programming languages, it
17522 seems desirable that the name of a package for a Python module contains
17523 the word @code{python}.
17525 Some modules are compatible with only one version of Python, others with both.
17526 If the package Foo compiles only with Python 3, we name it
17527 @code{python-foo}; if it compiles only with Python 2, we name it
17528 @code{python2-foo}. If it is compatible with both versions, we create two
17529 packages with the corresponding names.
17531 If a project already contains the word @code{python}, we drop this;
17532 for instance, the module python-dateutil is packaged under the names
17533 @code{python-dateutil} and @code{python2-dateutil}. If the project name
17534 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
17537 @subsubsection Specifying Dependencies
17538 @cindex inputs, for Python packages
17540 Dependency information for Python packages is usually available in the
17541 package source tree, with varying degrees of accuracy: in the
17542 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
17544 Your mission, when writing a recipe for a Python package, is to map
17545 these dependencies to the appropriate type of ``input'' (@pxref{package
17546 Reference, inputs}). Although the @code{pypi} importer normally does a
17547 good job (@pxref{Invoking guix import}), you may want to check the
17548 following check list to determine which dependency goes where.
17553 We currently package Python 2 with @code{setuptools} and @code{pip}
17554 installed like Python 3.4 has per default. Thus you don't need to
17555 specify either of these as an input. @command{guix lint} will warn you
17559 Python dependencies required at run time go into
17560 @code{propagated-inputs}. They are typically defined with the
17561 @code{install_requires} keyword in @file{setup.py}, or in the
17562 @file{requirements.txt} file.
17565 Python packages required only at build time---e.g., those listed with
17566 the @code{setup_requires} keyword in @file{setup.py}---or only for
17567 testing---e.g., those in @code{tests_require}---go into
17568 @code{native-inputs}. The rationale is that (1) they do not need to be
17569 propagated because they are not needed at run time, and (2) in a
17570 cross-compilation context, it's the ``native'' input that we'd want.
17572 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
17573 frameworks. Of course if any of these packages is also required at
17574 run-time, it needs to go to @code{propagated-inputs}.
17577 Anything that does not fall in the previous categories goes to
17578 @code{inputs}, for example programs or C libraries required for building
17579 Python packages containing C extensions.
17582 If a Python package has optional dependencies (@code{extras_require}),
17583 it is up to you to decide whether to add them or not, based on their
17584 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
17591 @subsection Perl Modules
17594 Perl programs standing for themselves are named as any other package,
17595 using the lowercase upstream name.
17596 For Perl packages containing a single class, we use the lowercase class name,
17597 replace all occurrences of @code{::} by dashes and prepend the prefix
17599 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
17600 Modules containing several classes keep their lowercase upstream name and
17601 are also prepended by @code{perl-}. Such modules tend to have the word
17602 @code{perl} somewhere in their name, which gets dropped in favor of the
17603 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
17606 @node Java Packages
17607 @subsection Java Packages
17610 Java programs standing for themselves are named as any other package,
17611 using the lowercase upstream name.
17613 To avoid confusion and naming clashes with other programming languages,
17614 it is desirable that the name of a package for a Java package is
17615 prefixed with @code{java-}. If a project already contains the word
17616 @code{java}, we drop this; for instance, the package @code{ngsjava} is
17617 packaged under the name @code{java-ngs}.
17619 For Java packages containing a single class or a small class hierarchy,
17620 we use the lowercase class name, replace all occurrences of @code{.} by
17621 dashes and prepend the prefix @code{java-}. So the class
17622 @code{apache.commons.cli} becomes package
17623 @code{java-apache-commons-cli}.
17630 For fonts that are in general not installed by a user for typesetting
17631 purposes, or that are distributed as part of a larger software package,
17632 we rely on the general packaging rules for software; for instance, this
17633 applies to the fonts delivered as part of the X.Org system or fonts that
17634 are part of TeX Live.
17636 To make it easier for a user to search for fonts, names for other packages
17637 containing only fonts are constructed as follows, independently of the
17638 upstream package name.
17640 The name of a package containing only one font family starts with
17641 @code{font-}; it is followed by the foundry name and a dash @code{-}
17642 if the foundry is known, and the font family name, in which spaces are
17643 replaced by dashes (and as usual, all upper case letters are transformed
17645 For example, the Gentium font family by SIL is packaged under the name
17646 @code{font-sil-gentium}.
17648 For a package containing several font families, the name of the collection
17649 is used in the place of the font family name.
17650 For instance, the Liberation fonts consist of three families,
17651 Liberation Sans, Liberation Serif and Liberation Mono.
17652 These could be packaged separately under the names
17653 @code{font-liberation-sans} and so on; but as they are distributed together
17654 under a common name, we prefer to package them together as
17655 @code{font-liberation}.
17657 In the case where several formats of the same font family or font collection
17658 are packaged separately, a short form of the format, prepended by a dash,
17659 is added to the package name. We use @code{-ttf} for TrueType fonts,
17660 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
17665 @node Bootstrapping
17666 @section Bootstrapping
17668 @c Adapted from the ELS 2013 paper.
17670 @cindex bootstrapping
17672 Bootstrapping in our context refers to how the distribution gets built
17673 ``from nothing''. Remember that the build environment of a derivation
17674 contains nothing but its declared inputs (@pxref{Introduction}). So
17675 there's an obvious chicken-and-egg problem: how does the first package
17676 get built? How does the first compiler get compiled? Note that this is
17677 a question of interest only to the curious hacker, not to the regular
17678 user, so you can shamelessly skip this section if you consider yourself
17679 a ``regular user''.
17681 @cindex bootstrap binaries
17682 The GNU system is primarily made of C code, with libc at its core. The
17683 GNU build system itself assumes the availability of a Bourne shell and
17684 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
17685 `grep'. Furthermore, build programs---programs that run
17686 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
17687 (@pxref{Derivations}). Consequently, to be able to build anything at
17688 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
17689 Binutils, libc, and the other packages mentioned above---the
17690 @dfn{bootstrap binaries}.
17692 These bootstrap binaries are ``taken for granted'', though we can also
17693 re-create them if needed (more on that later).
17695 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
17697 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
17698 @c large image, it's hard to scroll. Oh well.
17699 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17701 The figure above shows the very beginning of the dependency graph of the
17702 distribution, corresponding to the package definitions of the @code{(gnu
17703 packages bootstrap)} module. A similar figure can be generated with
17704 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17707 guix graph -t derivation \
17708 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17712 At this level of detail, things are
17713 slightly complex. First, Guile itself consists of an ELF executable,
17714 along with many source and compiled Scheme files that are dynamically
17715 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17716 tarball shown in this graph. This tarball is part of Guix's ``source''
17717 distribution, and gets inserted into the store with @code{add-to-store}
17718 (@pxref{The Store}).
17720 But how do we write a derivation that unpacks this tarball and adds it
17721 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17722 derivation---the first one that gets built---uses @code{bash} as its
17723 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17724 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17725 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17726 the Guix source distribution, whose sole purpose is to allow the Guile
17727 tarball to be unpacked.
17729 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17730 Guile that can be used to run subsequent build programs. Its first task
17731 is to download tarballs containing the other pre-built binaries---this
17732 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17733 @code{ftp-client.scm} are used for this purpose. The
17734 @code{module-import.drv} derivations import those modules in a directory
17735 in the store, using the original layout. The
17736 @code{module-import-compiled.drv} derivations compile those modules, and
17737 write them in an output directory with the right layout. This
17738 corresponds to the @code{#:modules} argument of
17739 @code{build-expression->derivation} (@pxref{Derivations}).
17741 Finally, the various tarballs are unpacked by the
17742 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17743 etc., at which point we have a working C tool chain.
17746 @unnumberedsubsec Building the Build Tools
17748 Bootstrapping is complete when we have a full tool chain that does not
17749 depend on the pre-built bootstrap tools discussed above. This
17750 no-dependency requirement is verified by checking whether the files of
17751 the final tool chain contain references to the @file{/gnu/store}
17752 directories of the bootstrap inputs. The process that leads to this
17753 ``final'' tool chain is described by the package definitions found in
17754 the @code{(gnu packages commencement)} module.
17756 The @command{guix graph} command allows us to ``zoom out'' compared to
17757 the graph above, by looking at the level of package objects instead of
17758 individual derivations---remember that a package may translate to
17759 several derivations, typically one derivation to download its source,
17760 one to build the Guile modules it needs, and one to actually build the
17761 package from source. The command:
17764 guix graph -t bag \
17765 -e '(@@@@ (gnu packages commencement)
17766 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17770 produces the dependency graph leading to the ``final'' C
17771 library@footnote{You may notice the @code{glibc-intermediate} label,
17772 suggesting that it is not @emph{quite} final, but as a good
17773 approximation, we will consider it final.}, depicted below.
17775 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17777 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17778 The first tool that gets built with the bootstrap binaries is
17779 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17780 for all the following packages. From there Findutils and Diffutils get
17783 Then come the first-stage Binutils and GCC, built as pseudo cross
17784 tools---i.e., with @code{--target} equal to @code{--host}. They are
17785 used to build libc. Thanks to this cross-build trick, this libc is
17786 guaranteed not to hold any reference to the initial tool chain.
17788 From there the final Binutils and GCC (not shown above) are built.
17790 from the final Binutils, and links programs against the just-built libc.
17791 This tool chain is used to build the other packages used by Guix and by
17792 the GNU Build System: Guile, Bash, Coreutils, etc.
17794 And voilà! At this point we have the complete set of build tools that
17795 the GNU Build System expects. These are in the @code{%final-inputs}
17796 variable of the @code{(gnu packages commencement)} module, and are
17797 implicitly used by any package that uses @code{gnu-build-system}
17798 (@pxref{Build Systems, @code{gnu-build-system}}).
17801 @unnumberedsubsec Building the Bootstrap Binaries
17803 @cindex bootstrap binaries
17804 Because the final tool chain does not depend on the bootstrap binaries,
17805 those rarely need to be updated. Nevertheless, it is useful to have an
17806 automated way to produce them, should an update occur, and this is what
17807 the @code{(gnu packages make-bootstrap)} module provides.
17809 The following command builds the tarballs containing the bootstrap
17810 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17811 of Coreutils and other basic command-line tools):
17814 guix build bootstrap-tarballs
17817 The generated tarballs are those that should be referred to in the
17818 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17821 Still here? Then perhaps by now you've started to wonder: when do we
17822 reach a fixed point? That is an interesting question! The answer is
17823 unknown, but if you would like to investigate further (and have
17824 significant computational and storage resources to do so), then let us
17828 @section Porting to a New Platform
17830 As discussed above, the GNU distribution is self-contained, and
17831 self-containment is achieved by relying on pre-built ``bootstrap
17832 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17833 operating system kernel, CPU architecture, and application binary
17834 interface (ABI). Thus, to port the distribution to a platform that is
17835 not yet supported, one must build those bootstrap binaries, and update
17836 the @code{(gnu packages bootstrap)} module to use them on that platform.
17838 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17839 When everything goes well, and assuming the GNU tool chain supports the
17840 target platform, this can be as simple as running a command like this
17844 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17847 For this to work, the @code{glibc-dynamic-linker} procedure in
17848 @code{(gnu packages bootstrap)} must be augmented to return the right
17849 file name for libc's dynamic linker on that platform; likewise,
17850 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17851 taught about the new platform.
17853 Once these are built, the @code{(gnu packages bootstrap)} module needs
17854 to be updated to refer to these binaries on the target platform. That
17855 is, the hashes and URLs of the bootstrap tarballs for the new platform
17856 must be added alongside those of the currently supported platforms. The
17857 bootstrap Guile tarball is treated specially: it is expected to be
17858 available locally, and @file{gnu/local.mk} has rules do download it for
17859 the supported architectures; a rule for the new platform must be added
17862 In practice, there may be some complications. First, it may be that the
17863 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17864 above) is not recognized by all the GNU tools. Typically, glibc
17865 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17866 configure flag (see @code{gcc.scm} for examples of how to handle this).
17867 Second, some of the required packages could fail to build for that
17868 platform. Lastly, the generated binaries could be broken for some
17871 @c *********************************************************************
17872 @include contributing.texi
17874 @c *********************************************************************
17875 @node Acknowledgments
17876 @chapter Acknowledgments
17878 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17879 which was designed and
17880 implemented by Eelco Dolstra, with contributions from other people (see
17881 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17882 management, and promoted unprecedented features, such as transactional
17883 package upgrades and rollbacks, per-user profiles, and referentially
17884 transparent build processes. Without this work, Guix would not exist.
17886 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17887 an inspiration for Guix.
17889 GNU@tie{}Guix itself is a collective work with contributions from a
17890 number of people. See the @file{AUTHORS} file in Guix for more
17891 information on these fine people. The @file{THANKS} file lists people
17892 who have helped by reporting bugs, taking care of the infrastructure,
17893 providing artwork and themes, making suggestions, and more---thank you!
17896 @c *********************************************************************
17897 @node GNU Free Documentation License
17898 @appendix GNU Free Documentation License
17899 @cindex license, GNU Free Documentation License
17900 @include fdl-1.3.texi
17902 @c *********************************************************************
17903 @node Concept Index
17904 @unnumbered Concept Index
17907 @node Programming Index
17908 @unnumbered Programming Index
17909 @syncodeindex tp fn
17910 @syncodeindex vr fn
17915 @c Local Variables:
17916 @c ispell-local-dictionary: "american";