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.
161 * Invoking guix weather:: Assessing substitute availability.
163 Invoking @command{guix build}
165 * Common Build Options:: Build options for most commands.
166 * Package Transformation Options:: Creating variants of packages.
167 * Additional Build Options:: Options specific to 'guix build'.
168 * Debugging Build Failures:: Real life packaging experience.
172 * System Installation:: Installing the whole operating system.
173 * System Configuration:: Configuring the operating system.
174 * Documentation:: Browsing software user manuals.
175 * Installing Debugging Files:: Feeding the debugger.
176 * Security Updates:: Deploying security fixes quickly.
177 * Package Modules:: Packages from the programmer's viewpoint.
178 * Packaging Guidelines:: Growing the distribution.
179 * Bootstrapping:: GNU/Linux built from scratch.
180 * Porting:: Targeting another platform or kernel.
184 * Limitations:: What you can expect.
185 * Hardware Considerations:: Supported hardware.
186 * USB Stick Installation:: Preparing the installation medium.
187 * Preparing for Installation:: Networking, partitioning, etc.
188 * Proceeding with the Installation:: The real thing.
189 * Installing GuixSD in a VM:: GuixSD playground.
190 * Building the Installation Image:: How this comes to be.
194 * Using the Configuration System:: Customizing your GNU system.
195 * operating-system Reference:: Detail of operating-system declarations.
196 * File Systems:: Configuring file system mounts.
197 * Mapped Devices:: Block device extra processing.
198 * User Accounts:: Specifying user accounts.
199 * Locales:: Language and cultural convention settings.
200 * Services:: Specifying system services.
201 * Setuid Programs:: Programs running with root privileges.
202 * X.509 Certificates:: Authenticating HTTPS servers.
203 * Name Service Switch:: Configuring libc's name service switch.
204 * Initial RAM Disk:: Linux-Libre bootstrapping.
205 * Bootloader Configuration:: Configuring the boot loader.
206 * Invoking guix system:: Instantiating a system configuration.
207 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
208 * Defining Services:: Adding new service definitions.
212 * Base Services:: Essential system services.
213 * Scheduled Job Execution:: The mcron service.
214 * Log Rotation:: The rottlog service.
215 * Networking Services:: Network setup, SSH daemon, etc.
216 * X Window:: Graphical display.
217 * Printing Services:: Local and remote printer support.
218 * Desktop Services:: D-Bus and desktop services.
219 * Database Services:: SQL databases.
220 * Mail Services:: IMAP, POP3, SMTP, and all that.
221 * Messaging Services:: Messaging services.
222 * Kerberos Services:: Kerberos services.
223 * Web Services:: Web servers.
224 * DNS Services:: DNS daemons.
225 * VPN Services:: VPN daemons.
226 * Network File System:: NFS related services.
227 * Continuous Integration:: The Cuirass service.
228 * Power management Services:: The TLP tool.
229 * Miscellaneous Services:: Other services.
233 * Service Composition:: The model for composing services.
234 * Service Types and Services:: Types and services.
235 * Service Reference:: API reference.
236 * Shepherd Services:: A particular type of service.
240 * Software Freedom:: What may go into the distribution.
241 * Package Naming:: What's in a name?
242 * Version Numbers:: When the name is not enough.
243 * Synopses and Descriptions:: Helping users find the right package.
244 * Python Modules:: A touch of British comedy.
245 * Perl Modules:: Little pearls.
246 * Java Packages:: Coffee break.
247 * Fonts:: Fond of fonts.
251 * Building from Git:: The latest and greatest.
252 * Running Guix Before It Is Installed:: Hacker tricks.
253 * The Perfect Setup:: The right tools.
254 * Coding Style:: Hygiene of the contributor.
255 * Submitting Patches:: Share your work.
259 * Programming Paradigm:: How to compose your elements.
260 * Modules:: Where to store your code?
261 * Data Types and Pattern Matching:: Implementing data structures.
262 * Formatting Code:: Writing conventions.
267 @c *********************************************************************
269 @chapter Introduction
272 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
273 using the international phonetic alphabet (IPA).} is a package
274 management tool for the GNU system. Guix makes it easy for unprivileged
275 users to install, upgrade, or remove packages, to roll back to a
276 previous package set, to build packages from source, and generally
277 assists with the creation and maintenance of software environments.
279 @cindex user interfaces
280 Guix provides a command-line package management interface
281 (@pxref{Invoking guix package}), a set of command-line utilities
282 (@pxref{Utilities}), as well as Scheme programming interfaces
283 (@pxref{Programming Interface}).
285 Its @dfn{build daemon} is responsible for building packages on behalf of
286 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
287 binaries from authorized sources (@pxref{Substitutes}).
289 @cindex extensibility of the distribution
290 @cindex customization, of packages
291 Guix includes package definitions for many GNU and non-GNU packages, all
292 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
293 user's computing freedom}. It is @emph{extensible}: users can write
294 their own package definitions (@pxref{Defining Packages}) and make them
295 available as independent package modules (@pxref{Package Modules}). It
296 is also @emph{customizable}: users can @emph{derive} specialized package
297 definitions from existing ones, including from the command line
298 (@pxref{Package Transformation Options}).
300 @cindex Guix System Distribution
302 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
303 where it complements the available tools without interference
304 (@pxref{Installation}), or you can use it as part of the standalone
305 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
306 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
307 system configuration and Guix takes care of instantiating the
308 configuration in a transactional, reproducible, and stateless fashion
309 (@pxref{System Configuration}).
311 @cindex functional package management
312 Under the hood, Guix implements the @dfn{functional package management}
313 discipline pioneered by Nix (@pxref{Acknowledgments}).
314 In Guix, the package build and installation process is seen
315 as a @emph{function}, in the mathematical sense. That function takes inputs,
316 such as build scripts, a compiler, and libraries, and
317 returns an installed package. As a pure function, its result depends
318 solely on its inputs---for instance, it cannot refer to software or
319 scripts that were not explicitly passed as inputs. A build function
320 always produces the same result when passed a given set of inputs. It
321 cannot alter the environment of the running system in
322 any way; for instance, it cannot create, modify, or delete files outside
323 of its build and installation directories. This is achieved by running
324 build processes in isolated environments (or @dfn{containers}), where only their
325 explicit inputs are visible.
328 The result of package build functions is @dfn{cached} in the file
329 system, in a special directory called @dfn{the store} (@pxref{The
330 Store}). Each package is installed in a directory of its own in the
331 store---by default under @file{/gnu/store}. The directory name contains
332 a hash of all the inputs used to build that package; thus, changing an
333 input yields a different directory name.
335 This approach is the foundation for the salient features of Guix: support
336 for transactional package upgrade and rollback, per-user installation, and
337 garbage collection of packages (@pxref{Features}).
340 @c *********************************************************************
342 @chapter Installation
344 @cindex installing Guix
345 GNU Guix is available for download from its website at
346 @url{http://www.gnu.org/software/guix/}. This section describes the
347 software requirements of Guix, as well as how to install it and get
350 Note that this section is concerned with the installation of the package
351 manager, which can be done on top of a running GNU/Linux system. If,
352 instead, you want to install the complete GNU operating system,
353 @pxref{System Installation}.
355 @cindex foreign distro
356 When installed on a running GNU/Linux system---thereafter called a
357 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
358 without interference. Its data lives exclusively in two directories,
359 usually @file{/gnu/store} and @file{/var/guix}; other files on your
360 system, such as @file{/etc}, are left untouched.
362 Once installed, Guix can be updated by running @command{guix pull}
363 (@pxref{Invoking guix pull}).
366 * Binary Installation:: Getting Guix running in no time!
367 * Requirements:: Software needed to build and run Guix.
368 * Running the Test Suite:: Testing Guix.
369 * Setting Up the Daemon:: Preparing the build daemon's environment.
370 * Invoking guix-daemon:: Running the build daemon.
371 * Application Setup:: Application-specific setup.
374 @node Binary Installation
375 @section Binary Installation
377 @cindex installing Guix from binaries
378 This section describes how to install Guix on an arbitrary system from a
379 self-contained tarball providing binaries for Guix and for all its
380 dependencies. This is often quicker than installing from source, which
381 is described in the next sections. The only requirement is to have
384 Installing goes along these lines:
388 @cindex downloading Guix binary
389 Download the binary tarball from
390 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
391 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
392 already running the kernel Linux, and so on.
394 @c The following is somewhat duplicated in ``System Installation''.
395 Make sure to download the associated @file{.sig} file and to verify the
396 authenticity of the tarball against it, along these lines:
399 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
400 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
403 If that command fails because you do not have the required public key,
404 then run this command to import it:
407 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
411 and rerun the @code{gpg --verify} command.
412 @c end authentication part
419 # tar --warning=no-timestamp -xf \
420 guix-binary-@value{VERSION}.@var{system}.tar.xz
421 # mv var/guix /var/ && mv gnu /
424 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
425 The latter contains a ready-to-use profile for @code{root} (see next
428 Do @emph{not} unpack the tarball on a working Guix system since that
429 would overwrite its own essential files.
431 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
432 not emit warnings about ``implausibly old time stamps'' (such
433 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
435 They stem from the fact that all the
436 files in the archive have their modification time set to zero (which
437 means January 1st, 1970.) This is done on purpose to make sure the
438 archive content is independent of its creation time, thus making it
442 Make @code{root}'s profile available under @file{~/.guix-profile}:
445 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
449 Source @file{etc/profile} to augment @code{PATH} and other relevant
450 environment variables:
453 # GUIX_PROFILE=$HOME/.guix-profile \
454 source $GUIX_PROFILE/etc/profile
458 Create the group and user accounts for build users as explained below
459 (@pxref{Build Environment Setup}).
462 Run the daemon, and set it to automatically start on boot.
464 If your host distro uses the systemd init system, this can be achieved
467 @c Versions of systemd that supported symlinked service files are not
468 @c yet widely deployed, so we should suggest that users copy the service
471 @c See this thread for more information:
472 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
475 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
477 # systemctl start guix-daemon && systemctl enable guix-daemon
480 If your host distro uses the Upstart init system:
483 # initctl reload-configuration
484 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
488 Otherwise, you can still start the daemon manually with:
491 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
495 Make the @command{guix} command available to other users on the machine,
499 # mkdir -p /usr/local/bin
501 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
504 It is also a good idea to make the Info version of this manual available
508 # mkdir -p /usr/local/share/info
509 # cd /usr/local/share/info
510 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
514 That way, assuming @file{/usr/local/share/info} is in the search path,
515 running @command{info guix} will open this manual (@pxref{Other Info
516 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
520 @cindex substitutes, authorization thereof
521 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
522 (@pxref{Substitutes}), authorize them:
525 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
529 Each user may need to perform a few additional steps to make their Guix
530 environment ready for use, @pxref{Application Setup}.
533 Voilà, the installation is complete!
535 You can confirm that Guix is working by installing a sample package into
539 # guix package -i hello
542 The @code{guix} package must remain available in @code{root}'s profile,
543 or it would become subject to garbage collection---in which case you
544 would find yourself badly handicapped by the lack of the @command{guix}
545 command. In other words, do not remove @code{guix} by running
546 @code{guix package -r guix}.
548 The binary installation tarball can be (re)produced and verified simply
549 by running the following command in the Guix source tree:
552 make guix-binary.@var{system}.tar.xz
556 ... which, in turn, runs:
559 guix pack -s @var{system} --localstatedir guix
562 @xref{Invoking guix pack}, for more info on this handy tool.
565 @section Requirements
567 This section lists requirements when building Guix from source. The
568 build procedure for Guix is the same as for other GNU software, and is
569 not covered here. Please see the files @file{README} and @file{INSTALL}
570 in the Guix source tree for additional details.
572 GNU Guix depends on the following packages:
575 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
576 later, including 2.2.x;
577 @item @url{http://gnupg.org/, GNU libgcrypt};
579 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
580 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
581 Guile,, gnutls-guile, GnuTLS-Guile});
582 @item @url{http://www.gnu.org/software/make/, GNU Make}.
585 The following dependencies are optional:
590 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
591 allow you to use the @command{guix import pypi} command (@pxref{Invoking
592 guix import}). It is of
593 interest primarily for developers and not for casual users.
596 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
597 Support for build offloading (@pxref{Daemon Offload Setup}) and
598 @command{guix copy} (@pxref{Invoking guix copy}) depends on
599 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
600 version 0.10.2 or later.
603 When @url{http://zlib.net, zlib} is available, @command{guix publish}
604 can compress build byproducts (@pxref{Invoking guix publish}).
607 Unless @code{--disable-daemon} was passed to @command{configure}, the
608 following packages are also needed:
611 @item @url{http://sqlite.org, SQLite 3};
612 @item @url{http://www.bzip.org, libbz2};
613 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
617 @cindex state directory
618 When configuring Guix on a system that already has a Guix installation,
619 be sure to specify the same state directory as the existing installation
620 using the @code{--localstatedir} option of the @command{configure}
621 script (@pxref{Directory Variables, @code{localstatedir},, standards,
622 GNU Coding Standards}). The @command{configure} script protects against
623 unintended misconfiguration of @var{localstatedir} so you do not
624 inadvertently corrupt your store (@pxref{The Store}).
626 @cindex Nix, compatibility
627 When a working installation of @url{http://nixos.org/nix/, the Nix package
628 manager} is available, you
629 can instead configure Guix with @code{--disable-daemon}. In that case,
630 Nix replaces the three dependencies above.
632 Guix is compatible with Nix, so it is possible to share the same store
633 between both. To do so, you must pass @command{configure} not only the
634 same @code{--with-store-dir} value, but also the same
635 @code{--localstatedir} value. The latter is essential because it
636 specifies where the database that stores metadata about the store is
637 located, among other things. The default values for Nix are
638 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
639 Note that @code{--disable-daemon} is not required if
640 your goal is to share the store with Nix.
642 @node Running the Test Suite
643 @section Running the Test Suite
646 After a successful @command{configure} and @code{make} run, it is a good
647 idea to run the test suite. It can help catch issues with the setup or
648 environment, or bugs in Guix itself---and really, reporting test
649 failures is a good way to help improve the software. To run the test
656 Test cases can run in parallel: you can use the @code{-j} option of
657 GNU@tie{}make to speed things up. The first run may take a few minutes
658 on a recent machine; subsequent runs will be faster because the store
659 that is created for test purposes will already have various things in
662 It is also possible to run a subset of the tests by defining the
663 @code{TESTS} makefile variable as in this example:
666 make check TESTS="tests/store.scm tests/cpio.scm"
669 By default, tests results are displayed at a file level. In order to
670 see the details of every individual test cases, it is possible to define
671 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
674 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
677 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
678 @file{test-suite.log} file. Please specify the Guix version being used
679 as well as version numbers of the dependencies (@pxref{Requirements}) in
682 Guix also comes with a whole-system test suite that tests complete
683 GuixSD operating system instances. It can only run on systems where
684 Guix is already installed, using:
691 or, again, by defining @code{TESTS} to select a subset of tests to run:
694 make check-system TESTS="basic mcron"
697 These system tests are defined in the @code{(gnu tests @dots{})}
698 modules. They work by running the operating systems under test with
699 lightweight instrumentation in a virtual machine (VM). They can be
700 computationally intensive or rather cheap, depending on whether
701 substitutes are available for their dependencies (@pxref{Substitutes}).
702 Some of them require a lot of storage space to hold VM images.
704 Again in case of test failures, please send @email{bug-guix@@gnu.org}
707 @node Setting Up the Daemon
708 @section Setting Up the Daemon
711 Operations such as building a package or running the garbage collector
712 are all performed by a specialized process, the @dfn{build daemon}, on
713 behalf of clients. Only the daemon may access the store and its
714 associated database. Thus, any operation that manipulates the store
715 goes through the daemon. For instance, command-line tools such as
716 @command{guix package} and @command{guix build} communicate with the
717 daemon (@i{via} remote procedure calls) to instruct it what to do.
719 The following sections explain how to prepare the build daemon's
720 environment. See also @ref{Substitutes}, for information on how to allow
721 the daemon to download pre-built binaries.
724 * Build Environment Setup:: Preparing the isolated build environment.
725 * Daemon Offload Setup:: Offloading builds to remote machines.
728 @node Build Environment Setup
729 @subsection Build Environment Setup
731 @cindex build environment
732 In a standard multi-user setup, Guix and its daemon---the
733 @command{guix-daemon} program---are installed by the system
734 administrator; @file{/gnu/store} is owned by @code{root} and
735 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
736 Guix tools to build packages or otherwise access the store, and the
737 daemon will do it on their behalf, ensuring that the store is kept in a
738 consistent state, and allowing built packages to be shared among users.
741 When @command{guix-daemon} runs as @code{root}, you may not want package
742 build processes themselves to run as @code{root} too, for obvious
743 security reasons. To avoid that, a special pool of @dfn{build users}
744 should be created for use by build processes started by the daemon.
745 These build users need not have a shell and a home directory: they will
746 just be used when the daemon drops @code{root} privileges in build
747 processes. Having several such users allows the daemon to launch
748 distinct build processes under separate UIDs, which guarantees that they
749 do not interfere with each other---an essential feature since builds are
750 regarded as pure functions (@pxref{Introduction}).
752 On a GNU/Linux system, a build user pool may be created like this (using
753 Bash syntax and the @code{shadow} commands):
755 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
756 @c for why `-G' is needed.
758 # groupadd --system guixbuild
759 # for i in `seq -w 1 10`;
761 useradd -g guixbuild -G guixbuild \
762 -d /var/empty -s `which nologin` \
763 -c "Guix build user $i" --system \
769 The number of build users determines how many build jobs may run in
770 parallel, as specified by the @option{--max-jobs} option
771 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
772 @command{guix system vm} and related commands, you may need to add the
773 build users to the @code{kvm} group so they can access @file{/dev/kvm},
774 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
775 (@pxref{Invoking guix system}).
777 The @code{guix-daemon} program may then be run as @code{root} with the
778 following command@footnote{If your machine uses the systemd init system,
779 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
780 file in @file{/etc/systemd/system} will ensure that
781 @command{guix-daemon} is automatically started. Similarly, if your
782 machine uses the Upstart init system, drop the
783 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
784 file in @file{/etc/init}.}:
787 # guix-daemon --build-users-group=guixbuild
792 This way, the daemon starts build processes in a chroot, under one of
793 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
794 environment contains nothing but:
796 @c Keep this list in sync with libstore/build.cc! -----------------------
799 a minimal @code{/dev} directory, created mostly independently from the
800 host @code{/dev}@footnote{``Mostly'', because while the set of files
801 that appear in the chroot's @code{/dev} is fixed, most of these files
802 can only be created if the host has them.};
805 the @code{/proc} directory; it only shows the processes of the container
806 since a separate PID name space is used;
809 @file{/etc/passwd} with an entry for the current user and an entry for
813 @file{/etc/group} with an entry for the user's group;
816 @file{/etc/hosts} with an entry that maps @code{localhost} to
820 a writable @file{/tmp} directory.
823 You can influence the directory where the daemon stores build trees
824 @i{via} the @code{TMPDIR} environment variable. However, the build tree
825 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
826 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
827 This way, the value of @code{TMPDIR} does not leak inside build
828 environments, which avoids discrepancies in cases where build processes
829 capture the name of their build tree.
832 The daemon also honors the @code{http_proxy} environment variable for
833 HTTP downloads it performs, be it for fixed-output derivations
834 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
836 If you are installing Guix as an unprivileged user, it is still possible
837 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
838 However, build processes will not be isolated from one another, and not
839 from the rest of the system. Thus, build processes may interfere with
840 each other, and may access programs, libraries, and other files
841 available on the system---making it much harder to view them as
842 @emph{pure} functions.
845 @node Daemon Offload Setup
846 @subsection Using the Offload Facility
850 When desired, the build daemon can @dfn{offload} derivation builds to
851 other machines running Guix, using the @code{offload} @dfn{build
852 hook}@footnote{This feature is available only when
853 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
855 feature is enabled, a list of user-specified build machines is read from
856 @file{/etc/guix/machines.scm}; every time a build is requested, for
857 instance via @code{guix build}, the daemon attempts to offload it to one
858 of the machines that satisfy the constraints of the derivation, in
859 particular its system type---e.g., @file{x86_64-linux}. Missing
860 prerequisites for the build are copied over SSH to the target machine,
861 which then proceeds with the build; upon success the output(s) of the
862 build are copied back to the initial machine.
864 The @file{/etc/guix/machines.scm} file typically looks like this:
868 (name "eightysix.example.org")
869 (system "x86_64-linux")
870 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
872 (speed 2.)) ;incredibly fast!
875 (name "meeps.example.org")
876 (system "mips64el-linux")
877 (host-key "ssh-rsa AAAAB3Nza@dots{}")
880 (string-append (getenv "HOME")
881 "/.ssh/identity-for-guix"))))
885 In the example above we specify a list of two build machines, one for
886 the @code{x86_64} architecture and one for the @code{mips64el}
889 In fact, this file is---not surprisingly!---a Scheme file that is
890 evaluated when the @code{offload} hook is started. Its return value
891 must be a list of @code{build-machine} objects. While this example
892 shows a fixed list of build machines, one could imagine, say, using
893 DNS-SD to return a list of potential build machines discovered in the
894 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
895 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
898 @deftp {Data Type} build-machine
899 This data type represents build machines to which the daemon may offload
900 builds. The important fields are:
905 The host name of the remote machine.
908 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
911 The user account to use when connecting to the remote machine over SSH.
912 Note that the SSH key pair must @emph{not} be passphrase-protected, to
913 allow non-interactive logins.
916 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
917 This is used to authenticate the machine when we connect to it. It is a
918 long string that looks like this:
921 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
924 If the machine is running the OpenSSH daemon, @command{sshd}, the host
925 key can be found in a file such as
926 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
928 If the machine is running the SSH daemon of GNU@tie{}lsh,
929 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
930 similar file. It can be converted to the OpenSSH format using
931 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
934 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
935 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
940 A number of optional fields may be specified:
944 @item @code{port} (default: @code{22})
945 Port number of SSH server on the machine.
947 @item @code{private-key} (default: @file{~root/.ssh/id_rsa})
948 The SSH private key file to use when connecting to the machine, in
951 Note that the default value is the private key @emph{of the root
952 account}. Make sure it exists if you use the default.
954 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
955 @itemx @code{compression-level} (default: @code{3})
956 The SSH-level compression methods and compression level requested.
958 Note that offloading relies on SSH compression to reduce bandwidth usage
959 when transferring files to and from build machines.
961 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
962 File name of the Unix-domain socket @command{guix-daemon} is listening
965 @item @code{parallel-builds} (default: @code{1})
966 The number of builds that may run in parallel on the machine.
968 @item @code{speed} (default: @code{1.0})
969 A ``relative speed factor''. The offload scheduler will tend to prefer
970 machines with a higher speed factor.
972 @item @code{features} (default: @code{'()})
973 A list of strings denoting specific features supported by the machine.
974 An example is @code{"kvm"} for machines that have the KVM Linux modules
975 and corresponding hardware support. Derivations can request features by
976 name, and they will be scheduled on matching build machines.
981 The @code{guile} command must be in the search path on the build
982 machines. In addition, the Guix modules must be in
983 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
984 this is the case by running:
987 ssh build-machine guile -c "'(use-modules (guix config))'"
990 There is one last thing to do once @file{machines.scm} is in place. As
991 explained above, when offloading, files are transferred back and forth
992 between the machine stores. For this to work, you first need to
993 generate a key pair on each machine to allow the daemon to export signed
994 archives of files from the store (@pxref{Invoking guix archive}):
997 # guix archive --generate-key
1001 Each build machine must authorize the key of the master machine so that
1002 it accepts store items it receives from the master:
1005 # guix archive --authorize < master-public-key.txt
1009 Likewise, the master machine must authorize the key of each build machine.
1011 All the fuss with keys is here to express pairwise mutual trust
1012 relations between the master and the build machines. Concretely, when
1013 the master receives files from a build machine (and @i{vice versa}), its
1014 build daemon can make sure they are genuine, have not been tampered
1015 with, and that they are signed by an authorized key.
1017 @cindex offload test
1018 To test whether your setup is operational, run this command on the
1025 This will attempt to connect to each of the build machines specified in
1026 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1027 available on each machine, attempt to export to the machine and import
1028 from it, and report any error in the process.
1030 If you want to test a different machine file, just specify it on the
1034 # guix offload test machines-qualif.scm
1037 Last, you can test the subset of the machines whose name matches a
1038 regular expression like this:
1041 # guix offload test machines.scm '\.gnu\.org$'
1044 @node Invoking guix-daemon
1045 @section Invoking @command{guix-daemon}
1047 The @command{guix-daemon} program implements all the functionality to
1048 access the store. This includes launching build processes, running the
1049 garbage collector, querying the availability of a build result, etc. It
1050 is normally run as @code{root} like this:
1053 # guix-daemon --build-users-group=guixbuild
1057 For details on how to set it up, @pxref{Setting Up the Daemon}.
1060 @cindex container, build environment
1061 @cindex build environment
1062 @cindex reproducible builds
1063 By default, @command{guix-daemon} launches build processes under
1064 different UIDs, taken from the build group specified with
1065 @code{--build-users-group}. In addition, each build process is run in a
1066 chroot environment that only contains the subset of the store that the
1067 build process depends on, as specified by its derivation
1068 (@pxref{Programming Interface, derivation}), plus a set of specific
1069 system directories. By default, the latter contains @file{/dev} and
1070 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1071 @dfn{container}: in addition to having its own file system tree, it has
1072 a separate mount name space, its own PID name space, network name space,
1073 etc. This helps achieve reproducible builds (@pxref{Features}).
1075 When the daemon performs a build on behalf of the user, it creates a
1076 build directory under @file{/tmp} or under the directory specified by
1077 its @code{TMPDIR} environment variable; this directory is shared with
1078 the container for the duration of the build. Be aware that using a
1079 directory other than @file{/tmp} can affect build results---for example,
1080 with a longer directory name, a build process that uses Unix-domain
1081 sockets might hit the name length limitation for @code{sun_path}, which
1082 it would otherwise not hit.
1084 The build directory is automatically deleted upon completion, unless the
1085 build failed and the client specified @option{--keep-failed}
1086 (@pxref{Invoking guix build, @option{--keep-failed}}).
1088 The following command-line options are supported:
1091 @item --build-users-group=@var{group}
1092 Take users from @var{group} to run build processes (@pxref{Setting Up
1093 the Daemon, build users}).
1095 @item --no-substitutes
1097 Do not use substitutes for build products. That is, always build things
1098 locally instead of allowing downloads of pre-built binaries
1099 (@pxref{Substitutes}).
1101 By default substitutes are used, unless the client---such as the
1102 @command{guix package} command---is explicitly invoked with
1103 @code{--no-substitutes}.
1105 When the daemon runs with @code{--no-substitutes}, clients can still
1106 explicitly enable substitution @i{via} the @code{set-build-options}
1107 remote procedure call (@pxref{The Store}).
1109 @item --substitute-urls=@var{urls}
1110 @anchor{daemon-substitute-urls}
1111 Consider @var{urls} the default whitespace-separated list of substitute
1112 source URLs. When this option is omitted,
1113 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1114 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1116 This means that substitutes may be downloaded from @var{urls}, as long
1117 as they are signed by a trusted signature (@pxref{Substitutes}).
1120 @item --no-build-hook
1121 Do not use the @dfn{build hook}.
1123 The build hook is a helper program that the daemon can start and to
1124 which it submits build requests. This mechanism is used to offload
1125 builds to other machines (@pxref{Daemon Offload Setup}).
1127 @item --cache-failures
1128 Cache build failures. By default, only successful builds are cached.
1130 When this option is used, @command{guix gc --list-failures} can be used
1131 to query the set of store items marked as failed; @command{guix gc
1132 --clear-failures} removes store items from the set of cached failures.
1133 @xref{Invoking guix gc}.
1135 @item --cores=@var{n}
1137 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1140 The default value is @code{0}, but it may be overridden by clients, such
1141 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1144 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1145 in the build process, which can then use it to exploit internal
1146 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1148 @item --max-jobs=@var{n}
1150 Allow at most @var{n} build jobs in parallel. The default value is
1151 @code{1}. Setting it to @code{0} means that no builds will be performed
1152 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1153 Setup}), or simply fail.
1155 @item --max-silent-time=@var{seconds}
1156 When the build or substitution process remains silent for more than
1157 @var{seconds}, terminate it and report a build failure.
1159 The default value is @code{0}, which disables the timeout.
1161 The value specified here can be overridden by clients (@pxref{Common
1162 Build Options, @code{--max-silent-time}}).
1164 @item --timeout=@var{seconds}
1165 Likewise, when the build or substitution process lasts for more than
1166 @var{seconds}, terminate it and report a build failure.
1168 The default value is @code{0}, which disables the timeout.
1170 The value specified here can be overridden by clients (@pxref{Common
1171 Build Options, @code{--timeout}}).
1173 @item --rounds=@var{N}
1174 Build each derivation @var{n} times in a row, and raise an error if
1175 consecutive build results are not bit-for-bit identical. Note that this
1176 setting can be overridden by clients such as @command{guix build}
1177 (@pxref{Invoking guix build}).
1179 When used in conjunction with @option{--keep-failed}, the differing
1180 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1181 This makes it easy to look for differences between the two results.
1184 Produce debugging output.
1186 This is useful to debug daemon start-up issues, but then it may be
1187 overridden by clients, for example the @code{--verbosity} option of
1188 @command{guix build} (@pxref{Invoking guix build}).
1190 @item --chroot-directory=@var{dir}
1191 Add @var{dir} to the build chroot.
1193 Doing this may change the result of build processes---for instance if
1194 they use optional dependencies found in @var{dir} when it is available,
1195 and not otherwise. For that reason, it is not recommended to do so.
1196 Instead, make sure that each derivation declares all the inputs that it
1199 @item --disable-chroot
1200 Disable chroot builds.
1202 Using this option is not recommended since, again, it would allow build
1203 processes to gain access to undeclared dependencies. It is necessary,
1204 though, when @command{guix-daemon} is running under an unprivileged user
1207 @item --disable-log-compression
1208 Disable compression of the build logs.
1210 Unless @code{--lose-logs} is used, all the build logs are kept in the
1211 @var{localstatedir}. To save space, the daemon automatically compresses
1212 them with bzip2 by default. This option disables that.
1214 @item --disable-deduplication
1215 @cindex deduplication
1216 Disable automatic file ``deduplication'' in the store.
1218 By default, files added to the store are automatically ``deduplicated'':
1219 if a newly added file is identical to another one found in the store,
1220 the daemon makes the new file a hard link to the other file. This can
1221 noticeably reduce disk usage, at the expense of slightly increased
1222 input/output load at the end of a build process. This option disables
1225 @item --gc-keep-outputs[=yes|no]
1226 Tell whether the garbage collector (GC) must keep outputs of live
1229 When set to ``yes'', the GC will keep the outputs of any live derivation
1230 available in the store---the @code{.drv} files. The default is ``no'',
1231 meaning that derivation outputs are kept only if they are GC roots.
1233 @item --gc-keep-derivations[=yes|no]
1234 Tell whether the garbage collector (GC) must keep derivations
1235 corresponding to live outputs.
1237 When set to ``yes'', as is the case by default, the GC keeps
1238 derivations---i.e., @code{.drv} files---as long as at least one of their
1239 outputs is live. This allows users to keep track of the origins of
1240 items in their store. Setting it to ``no'' saves a bit of disk space.
1242 Note that when both @code{--gc-keep-derivations} and
1243 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1244 prerequisites (the sources, compiler, libraries, and other build-time
1245 tools) of live objects in the store, regardless of whether these
1246 prerequisites are live. This is convenient for developers since it
1247 saves rebuilds or downloads.
1249 @item --impersonate-linux-2.6
1250 On Linux-based systems, impersonate Linux 2.6. This means that the
1251 kernel's @code{uname} system call will report 2.6 as the release number.
1253 This might be helpful to build programs that (usually wrongfully) depend
1254 on the kernel version number.
1257 Do not keep build logs. By default they are kept under
1258 @code{@var{localstatedir}/guix/log}.
1260 @item --system=@var{system}
1261 Assume @var{system} as the current system type. By default it is the
1262 architecture/kernel pair found at configure time, such as
1263 @code{x86_64-linux}.
1265 @item --listen=@var{endpoint}
1266 Listen for connections on @var{endpoint}. @var{endpoint} is interpreted
1267 as the file name of a Unix-domain socket if it starts with
1268 @code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a
1269 host name or host name and port to listen to. Here are a few examples:
1272 @item --listen=/gnu/var/daemon
1273 Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket,
1274 creating it if needed.
1276 @item --listen=localhost
1277 @cindex daemon, remote access
1278 @cindex remote access to the daemon
1279 @cindex daemon, cluster setup
1280 @cindex clusters, daemon setup
1281 Listen for TCP connections on the network interface corresponding to
1282 @code{localhost}, on port 44146.
1284 @item --listen=128.0.0.42:1234
1285 Listen for TCP connections on the network interface corresponding to
1286 @code{128.0.0.42}, on port 1234.
1289 This option can be repeated multiple times, in which case
1290 @command{guix-daemon} accepts connections on all the specified
1291 endpoints. Users can tell client commands what endpoint to connect to
1292 by setting the @code{GUIX_DAEMON_SOCKET} environment variable
1293 (@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}).
1296 The daemon protocol is @emph{unauthenticated and unencrypted}. Using
1297 @code{--listen=@var{host}} is suitable on local networks, such as
1298 clusters, where only trusted nodes may connect to the build daemon. In
1299 other cases where remote access to the daemon is needed, we recommend
1300 using Unix-domain sockets along with SSH.
1303 When @code{--listen} is omitted, @command{guix-daemon} listens for
1304 connections on the Unix-domain socket located at
1305 @file{@var{localstatedir}/daemon-socket/socket}.
1309 @node Application Setup
1310 @section Application Setup
1312 @cindex foreign distro
1313 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1314 so-called @dfn{foreign distro}---a few additional steps are needed to
1315 get everything in place. Here are some of them.
1319 @anchor{locales-and-locpath}
1320 @cindex locales, when not on GuixSD
1322 @vindex GUIX_LOCPATH
1323 Packages installed @i{via} Guix will not use the locale data of the
1324 host system. Instead, you must first install one of the locale packages
1325 available with Guix and then define the @code{GUIX_LOCPATH} environment
1329 $ guix package -i glibc-locales
1330 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1333 Note that the @code{glibc-locales} package contains data for all the
1334 locales supported by the GNU@tie{}libc and weighs in at around
1335 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1336 limited to a few UTF-8 locales.
1338 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1339 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1340 Manual}). There are two important differences though:
1344 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1345 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1346 to make sure the programs of the foreign distro will not end up loading
1347 incompatible locale data.
1350 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1351 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1352 should your Guix profile contain a mixture of programs linked against
1353 different libc version, each libc version will only try to load locale
1354 data in the right format.
1357 This is important because the locale data format used by different libc
1358 versions may be incompatible.
1360 @subsection Name Service Switch
1362 @cindex name service switch, glibc
1363 @cindex NSS (name service switch), glibc
1364 @cindex nscd (name service caching daemon)
1365 @cindex name service caching daemon (nscd)
1366 When using Guix on a foreign distro, we @emph{strongly recommend} that
1367 the system run the GNU C library's @dfn{name service cache daemon},
1368 @command{nscd}, which should be listening on the
1369 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1370 installed with Guix may fail to look up host names or user accounts, or
1371 may even crash. The next paragraphs explain why.
1373 @cindex @file{nsswitch.conf}
1374 The GNU C library implements a @dfn{name service switch} (NSS), which is
1375 an extensible mechanism for ``name lookups'' in general: host name
1376 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1377 The GNU C Library Reference Manual}).
1379 @cindex Network information service (NIS)
1380 @cindex NIS (Network information service)
1381 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1382 lookup implementations: for example, the @code{nss-mdns} plugin allow
1383 resolution of @code{.local} host names, the @code{nis} plugin allows
1384 user account lookup using the Network information service (NIS), and so
1385 on. These extra ``lookup services'' are configured system-wide in
1386 @file{/etc/nsswitch.conf}, and all the programs running on the system
1387 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1390 When they perform a name lookup---for instance by calling the
1391 @code{getaddrinfo} function in C---applications first try to connect to
1392 the nscd; on success, nscd performs name lookups on their behalf. If
1393 the nscd is not running, then they perform the name lookup by
1394 themselves, by loading the name lookup services into their own address
1395 space and running it. These name lookup services---the
1396 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1397 the host system's C library, rather than from the C library the
1398 application is linked against (the C library coming from Guix).
1400 And this is where the problem is: if your application is linked against
1401 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1402 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1403 likely crash or have its name lookups fail unexpectedly.
1405 Running @command{nscd} on the system, among other advantages, eliminates
1406 this binary incompatibility problem because those @code{libnss_*.so}
1407 files are loaded in the @command{nscd} process, not in applications
1410 @subsection X11 Fonts
1413 The majority of graphical applications use Fontconfig to locate and
1414 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1415 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1416 by default. Thus, to allow graphical applications installed with Guix
1417 to display fonts, you have to install fonts with Guix as well.
1418 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1419 @code{font-gnu-freefont-ttf}.
1421 To display text written in Chinese languages, Japanese, or Korean in
1422 graphical applications, consider installing
1423 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1424 has multiple outputs, one per language family (@pxref{Packages with
1425 Multiple Outputs}). For instance, the following command installs fonts
1426 for Chinese languages:
1429 guix package -i font-adobe-source-han-sans:cn
1432 @cindex @code{xterm}
1433 Older programs such as @command{xterm} do not use Fontconfig and instead
1434 rely on server-side font rendering. Such programs require to specify a
1435 full name of a font using XLFD (X Logical Font Description), like this:
1438 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1441 To be able to use such full names for the TrueType fonts installed in
1442 your Guix profile, you need to extend the font path of the X server:
1445 xset +fp ~/.guix-profile/share/fonts/truetype
1448 @cindex @code{xlsfonts}
1449 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1450 to make sure your TrueType fonts are listed there.
1452 @cindex @code{fc-cache}
1454 After installing fonts you may have to refresh the font cache to use
1455 them in applications. The same applies when applications installed via
1456 Guix do not seem to find fonts. To force rebuilding of the font cache
1457 run @code{fc-cache -f}. The @code{fc-cache} command is provided by the
1458 @code{fontconfig} package.
1460 @subsection X.509 Certificates
1462 @cindex @code{nss-certs}
1463 The @code{nss-certs} package provides X.509 certificates, which allow
1464 programs to authenticate Web servers accessed over HTTPS.
1466 When using Guix on a foreign distro, you can install this package and
1467 define the relevant environment variables so that packages know where to
1468 look for certificates. @xref{X.509 Certificates}, for detailed
1471 @subsection Emacs Packages
1473 @cindex @code{emacs}
1474 When you install Emacs packages with Guix, the elisp files may be placed
1475 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1477 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1478 directory exists because potentially there may exist thousands of Emacs
1479 packages and storing all their files in a single directory may be not
1480 reliable (because of name conflicts). So we think using a separate
1481 directory for each package is a good idea. It is very similar to how
1482 the Emacs package system organizes the file structure (@pxref{Package
1483 Files,,, emacs, The GNU Emacs Manual}).
1485 By default, Emacs (installed with Guix) ``knows'' where these packages
1486 are placed, so you do not need to perform any configuration. If, for
1487 some reason, you want to avoid auto-loading Emacs packages installed
1488 with Guix, you can do so by running Emacs with @code{--no-site-file}
1489 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1491 @subsection The GCC toolchain
1496 Guix offers individual compiler packages such as @code{gcc} but if you
1497 are in need of a complete toolchain for compiling and linking source
1498 code what you really want is the @code{gcc-toolchain} package. This
1499 package provides a complete GCC toolchain for C/C++ development,
1500 including GCC itself, the GNU C Library (headers and binaries, plus
1501 debugging symbols in the @code{debug} output), Binutils, and a linker
1504 @cindex attempt to use impure library, error message
1506 The wrapper's purpose is to inspect the @code{-L} and @code{-l} switches
1507 passed to the linker, add corresponding @code{-rpath} arguments, and
1508 invoke the actual linker with this new set of arguments. By default,
1509 the linker wrapper refuses to link to libraries outside the store to
1510 ensure ``purity''. This can be annoying when using the toolchain to
1511 link with local libraries. To allow references to libraries outside the
1512 store you need to define the environment variable
1513 @code{GUIX_LD_WRAPPER_ALLOW_IMPURITIES}.
1517 @c *********************************************************************
1518 @node Package Management
1519 @chapter Package Management
1522 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1523 remove software packages, without having to know about their build
1524 procedures or dependencies. Guix also goes beyond this obvious set of
1527 This chapter describes the main features of Guix, as well as the
1528 package management tools it provides. Along with the command-line
1529 interface described below (@pxref{Invoking guix package, @code{guix
1530 package}}), you may also use Emacs Interface (@pxref{Top,,,
1531 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1532 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1536 guix package -i emacs-guix
1540 * Features:: How Guix will make your life brighter.
1541 * Invoking guix package:: Package installation, removal, etc.
1542 * Substitutes:: Downloading pre-built binaries.
1543 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1544 * Invoking guix gc:: Running the garbage collector.
1545 * Invoking guix pull:: Fetching the latest Guix and distribution.
1546 * Invoking guix pack:: Creating software bundles.
1547 * Invoking guix archive:: Exporting and importing store files.
1553 When using Guix, each package ends up in the @dfn{package store}, in its
1554 own directory---something that resembles
1555 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1557 Instead of referring to these directories, users have their own
1558 @dfn{profile}, which points to the packages that they actually want to
1559 use. These profiles are stored within each user's home directory, at
1560 @code{$HOME/.guix-profile}.
1562 For example, @code{alice} installs GCC 4.7.2. As a result,
1563 @file{/home/alice/.guix-profile/bin/gcc} points to
1564 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1565 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1566 simply continues to point to
1567 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1568 coexist on the same system without any interference.
1570 The @command{guix package} command is the central tool to manage
1571 packages (@pxref{Invoking guix package}). It operates on the per-user
1572 profiles, and can be used @emph{with normal user privileges}.
1574 @cindex transactions
1575 The command provides the obvious install, remove, and upgrade
1576 operations. Each invocation is actually a @emph{transaction}: either
1577 the specified operation succeeds, or nothing happens. Thus, if the
1578 @command{guix package} process is terminated during the transaction,
1579 or if a power outage occurs during the transaction, then the user's
1580 profile remains in its previous state, and remains usable.
1582 In addition, any package transaction may be @emph{rolled back}. So, if,
1583 for example, an upgrade installs a new version of a package that turns
1584 out to have a serious bug, users may roll back to the previous instance
1585 of their profile, which was known to work well. Similarly, the global
1586 system configuration on GuixSD is subject to
1587 transactional upgrades and roll-back
1588 (@pxref{Using the Configuration System}).
1590 All packages in the package store may be @emph{garbage-collected}.
1591 Guix can determine which packages are still referenced by user
1592 profiles, and remove those that are provably no longer referenced
1593 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1594 generations of their profile so that the packages they refer to can be
1597 @cindex reproducibility
1598 @cindex reproducible builds
1599 Finally, Guix takes a @dfn{purely functional} approach to package
1600 management, as described in the introduction (@pxref{Introduction}).
1601 Each @file{/gnu/store} package directory name contains a hash of all the
1602 inputs that were used to build that package---compiler, libraries, build
1603 scripts, etc. This direct correspondence allows users to make sure a
1604 given package installation matches the current state of their
1605 distribution. It also helps maximize @dfn{build reproducibility}:
1606 thanks to the isolated build environments that are used, a given build
1607 is likely to yield bit-identical files when performed on different
1608 machines (@pxref{Invoking guix-daemon, container}).
1611 This foundation allows Guix to support @dfn{transparent binary/source
1612 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1613 available from an external source---a @dfn{substitute}, Guix just
1614 downloads it and unpacks it;
1615 otherwise, it builds the package from source, locally
1616 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1617 reproducible, users do not have to trust servers that provide
1618 substitutes: they can force a local build and @emph{challenge} providers
1619 (@pxref{Invoking guix challenge}).
1621 Control over the build environment is a feature that is also useful for
1622 developers. The @command{guix environment} command allows developers of
1623 a package to quickly set up the right development environment for their
1624 package, without having to manually install the dependencies of the
1625 package into their profile (@pxref{Invoking guix environment}).
1627 @node Invoking guix package
1628 @section Invoking @command{guix package}
1630 @cindex installing packages
1631 @cindex removing packages
1632 @cindex package installation
1633 @cindex package removal
1634 The @command{guix package} command is the tool that allows users to
1635 install, upgrade, and remove packages, as well as rolling back to
1636 previous configurations. It operates only on the user's own profile,
1637 and works with normal user privileges (@pxref{Features}). Its syntax
1641 guix package @var{options}
1643 @cindex transactions
1644 Primarily, @var{options} specifies the operations to be performed during
1645 the transaction. Upon completion, a new profile is created, but
1646 previous @dfn{generations} of the profile remain available, should the user
1649 For example, to remove @code{lua} and install @code{guile} and
1650 @code{guile-cairo} in a single transaction:
1653 guix package -r lua -i guile guile-cairo
1656 @command{guix package} also supports a @dfn{declarative approach}
1657 whereby the user specifies the exact set of packages to be available and
1658 passes it @i{via} the @option{--manifest} option
1659 (@pxref{profile-manifest, @option{--manifest}}).
1662 For each user, a symlink to the user's default profile is automatically
1663 created in @file{$HOME/.guix-profile}. This symlink always points to the
1664 current generation of the user's default profile. Thus, users can add
1665 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1666 variable, and so on.
1667 @cindex search paths
1668 If you are not using the Guix System Distribution, consider adding the
1669 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1670 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1671 shells get all the right environment variable definitions:
1674 GUIX_PROFILE="$HOME/.guix-profile" \
1675 source "$HOME/.guix-profile/etc/profile"
1678 In a multi-user setup, user profiles are stored in a place registered as
1679 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1680 to (@pxref{Invoking guix gc}). That directory is normally
1681 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1682 @var{localstatedir} is the value passed to @code{configure} as
1683 @code{--localstatedir}, and @var{user} is the user name. The
1684 @file{per-user} directory is created when @command{guix-daemon} is
1685 started, and the @var{user} sub-directory is created by @command{guix
1688 The @var{options} can be among the following:
1692 @item --install=@var{package} @dots{}
1693 @itemx -i @var{package} @dots{}
1694 Install the specified @var{package}s.
1696 Each @var{package} may specify either a simple package name, such as
1697 @code{guile}, or a package name followed by an at-sign and version number,
1698 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1699 case, the newest version prefixed by @code{1.8} is selected.)
1701 If no version number is specified, the
1702 newest available version will be selected. In addition, @var{package}
1703 may contain a colon, followed by the name of one of the outputs of the
1704 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1705 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1706 name (and optionally version) are searched for among the GNU
1707 distribution modules (@pxref{Package Modules}).
1709 @cindex propagated inputs
1710 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1711 that automatically get installed along with the required package
1712 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1713 @code{package} objects}, for information about propagated inputs in
1714 package definitions).
1716 @anchor{package-cmd-propagated-inputs}
1717 An example is the GNU MPC library: its C header files refer to those of
1718 the GNU MPFR library, which in turn refer to those of the GMP library.
1719 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1720 in the profile; removing MPC also removes MPFR and GMP---unless they had
1721 also been explicitly installed by the user.
1723 Besides, packages sometimes rely on the definition of environment
1724 variables for their search paths (see explanation of
1725 @code{--search-paths} below). Any missing or possibly incorrect
1726 environment variable definitions are reported here.
1728 @item --install-from-expression=@var{exp}
1730 Install the package @var{exp} evaluates to.
1732 @var{exp} must be a Scheme expression that evaluates to a
1733 @code{<package>} object. This option is notably useful to disambiguate
1734 between same-named variants of a package, with expressions such as
1735 @code{(@@ (gnu packages base) guile-final)}.
1737 Note that this option installs the first output of the specified
1738 package, which may be insufficient when needing a specific output of a
1739 multiple-output package.
1741 @item --install-from-file=@var{file}
1742 @itemx -f @var{file}
1743 Install the package that the code within @var{file} evaluates to.
1745 As an example, @var{file} might contain a definition like this
1746 (@pxref{Defining Packages}):
1749 @verbatiminclude package-hello.scm
1752 Developers may find it useful to include such a @file{guix.scm} file
1753 in the root of their project source tree that can be used to test
1754 development snapshots and create reproducible development environments
1755 (@pxref{Invoking guix environment}).
1757 @item --remove=@var{package} @dots{}
1758 @itemx -r @var{package} @dots{}
1759 Remove the specified @var{package}s.
1761 As for @code{--install}, each @var{package} may specify a version number
1762 and/or output name in addition to the package name. For instance,
1763 @code{-r glibc:debug} would remove the @code{debug} output of
1766 @item --upgrade[=@var{regexp} @dots{}]
1767 @itemx -u [@var{regexp} @dots{}]
1768 @cindex upgrading packages
1769 Upgrade all the installed packages. If one or more @var{regexp}s are
1770 specified, upgrade only installed packages whose name matches a
1771 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1773 Note that this upgrades package to the latest version of packages found
1774 in the distribution currently installed. To update your distribution,
1775 you should regularly run @command{guix pull} (@pxref{Invoking guix
1778 @item --do-not-upgrade[=@var{regexp} @dots{}]
1779 When used together with the @code{--upgrade} option, do @emph{not}
1780 upgrade any packages whose name matches a @var{regexp}. For example, to
1781 upgrade all packages in the current profile except those containing the
1782 substring ``emacs'':
1785 $ guix package --upgrade . --do-not-upgrade emacs
1788 @item @anchor{profile-manifest}--manifest=@var{file}
1789 @itemx -m @var{file}
1790 @cindex profile declaration
1791 @cindex profile manifest
1792 Create a new generation of the profile from the manifest object
1793 returned by the Scheme code in @var{file}.
1795 This allows you to @emph{declare} the profile's contents rather than
1796 constructing it through a sequence of @code{--install} and similar
1797 commands. The advantage is that @var{file} can be put under version
1798 control, copied to different machines to reproduce the same profile, and
1801 @c FIXME: Add reference to (guix profile) documentation when available.
1802 @var{file} must return a @dfn{manifest} object, which is roughly a list
1805 @findex packages->manifest
1807 (use-package-modules guile emacs)
1812 ;; Use a specific package output.
1813 (list guile-2.0 "debug")))
1816 @findex specifications->manifest
1817 In this example we have to know which modules define the @code{emacs}
1818 and @code{guile-2.0} variables to provide the right
1819 @code{use-package-modules} line, which can be cumbersome. We can
1820 instead provide regular package specifications and let
1821 @code{specifications->manifest} look up the corresponding package
1825 (specifications->manifest
1826 '("emacs" "guile@@2.2" "guile@@2.2:debug"))
1830 @cindex rolling back
1831 @cindex undoing transactions
1832 @cindex transactions, undoing
1833 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1834 the last transaction.
1836 When combined with options such as @code{--install}, roll back occurs
1837 before any other actions.
1839 When rolling back from the first generation that actually contains
1840 installed packages, the profile is made to point to the @dfn{zeroth
1841 generation}, which contains no files apart from its own metadata.
1843 After having rolled back, installing, removing, or upgrading packages
1844 overwrites previous future generations. Thus, the history of the
1845 generations in a profile is always linear.
1847 @item --switch-generation=@var{pattern}
1848 @itemx -S @var{pattern}
1850 Switch to a particular generation defined by @var{pattern}.
1852 @var{pattern} may be either a generation number or a number prefixed
1853 with ``+'' or ``-''. The latter means: move forward/backward by a
1854 specified number of generations. For example, if you want to return to
1855 the latest generation after @code{--roll-back}, use
1856 @code{--switch-generation=+1}.
1858 The difference between @code{--roll-back} and
1859 @code{--switch-generation=-1} is that @code{--switch-generation} will
1860 not make a zeroth generation, so if a specified generation does not
1861 exist, the current generation will not be changed.
1863 @item --search-paths[=@var{kind}]
1864 @cindex search paths
1865 Report environment variable definitions, in Bash syntax, that may be
1866 needed in order to use the set of installed packages. These environment
1867 variables are used to specify @dfn{search paths} for files used by some
1868 of the installed packages.
1870 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1871 environment variables to be defined so it can look for headers and
1872 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1873 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1874 library are installed in the profile, then @code{--search-paths} will
1875 suggest setting these variables to @code{@var{profile}/include} and
1876 @code{@var{profile}/lib}, respectively.
1878 The typical use case is to define these environment variables in the
1882 $ eval `guix package --search-paths`
1885 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1886 meaning that the returned environment variable definitions will either
1887 be exact settings, or prefixes or suffixes of the current value of these
1888 variables. When omitted, @var{kind} defaults to @code{exact}.
1890 This option can also be used to compute the @emph{combined} search paths
1891 of several profiles. Consider this example:
1894 $ guix package -p foo -i guile
1895 $ guix package -p bar -i guile-json
1896 $ guix package -p foo -p bar --search-paths
1899 The last command above reports about the @code{GUILE_LOAD_PATH}
1900 variable, even though, taken individually, neither @file{foo} nor
1901 @file{bar} would lead to that recommendation.
1904 @item --profile=@var{profile}
1905 @itemx -p @var{profile}
1906 Use @var{profile} instead of the user's default profile.
1909 Produce verbose output. In particular, emit the build log of the
1910 environment on the standard error port.
1913 Use the bootstrap Guile to build the profile. This option is only
1914 useful to distribution developers.
1918 In addition to these actions, @command{guix package} supports the
1919 following options to query the current state of a profile, or the
1920 availability of packages:
1924 @item --search=@var{regexp}
1925 @itemx -s @var{regexp}
1926 @cindex searching for packages
1927 List the available packages whose name, synopsis, or description matches
1928 @var{regexp}, sorted by relevance. Print all the metadata of matching packages in
1929 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1930 GNU recutils manual}).
1932 This allows specific fields to be extracted using the @command{recsel}
1933 command, for instance:
1936 $ guix package -s malloc | recsel -p name,version,relevance
1950 Similarly, to show the name of all the packages available under the
1951 terms of the GNU@tie{}LGPL version 3:
1954 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1961 It is also possible to refine search results using several @code{-s}
1962 flags. For example, the following command returns a list of board
1966 $ guix package -s '\<board\>' -s game | recsel -p name
1971 If we were to omit @code{-s game}, we would also get software packages
1972 that deal with printed circuit boards; removing the angle brackets
1973 around @code{board} would further add packages that have to do with
1976 And now for a more elaborate example. The following command searches
1977 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1978 libraries, and prints the name and synopsis of the matching packages:
1981 $ guix package -s crypto -s library | \
1982 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1986 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1987 information on @dfn{selection expressions} for @code{recsel -e}.
1989 @item --show=@var{package}
1990 Show details about @var{package}, taken from the list of available packages, in
1991 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1995 $ guix package --show=python | recsel -p name,version
2003 You may also specify the full name of a package to only get details about a
2004 specific version of it:
2006 $ guix package --show=python@@3.4 | recsel -p name,version
2013 @item --list-installed[=@var{regexp}]
2014 @itemx -I [@var{regexp}]
2015 List the currently installed packages in the specified profile, with the
2016 most recently installed packages shown last. When @var{regexp} is
2017 specified, list only installed packages whose name matches @var{regexp}.
2019 For each installed package, print the following items, separated by
2020 tabs: the package name, its version string, the part of the package that
2021 is installed (for instance, @code{out} for the default output,
2022 @code{include} for its headers, etc.), and the path of this package in
2025 @item --list-available[=@var{regexp}]
2026 @itemx -A [@var{regexp}]
2027 List packages currently available in the distribution for this system
2028 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
2029 installed packages whose name matches @var{regexp}.
2031 For each package, print the following items separated by tabs: its name,
2032 its version string, the parts of the package (@pxref{Packages with
2033 Multiple Outputs}), and the source location of its definition.
2035 @item --list-generations[=@var{pattern}]
2036 @itemx -l [@var{pattern}]
2038 Return a list of generations along with their creation dates; for each
2039 generation, show the installed packages, with the most recently
2040 installed packages shown last. Note that the zeroth generation is never
2043 For each installed package, print the following items, separated by
2044 tabs: the name of a package, its version string, the part of the package
2045 that is installed (@pxref{Packages with Multiple Outputs}), and the
2046 location of this package in the store.
2048 When @var{pattern} is used, the command returns only matching
2049 generations. Valid patterns include:
2052 @item @emph{Integers and comma-separated integers}. Both patterns denote
2053 generation numbers. For instance, @code{--list-generations=1} returns
2056 And @code{--list-generations=1,8,2} outputs three generations in the
2057 specified order. Neither spaces nor trailing commas are allowed.
2059 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
2060 specified generations and everything in between. Note that the start of
2061 a range must be smaller than its end.
2063 It is also possible to omit the endpoint. For example,
2064 @code{--list-generations=2..}, returns all generations starting from the
2067 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
2068 or months by passing an integer along with the first letter of the
2069 duration. For example, @code{--list-generations=20d} lists generations
2070 that are up to 20 days old.
2073 @item --delete-generations[=@var{pattern}]
2074 @itemx -d [@var{pattern}]
2075 When @var{pattern} is omitted, delete all generations except the current
2078 This command accepts the same patterns as @option{--list-generations}.
2079 When @var{pattern} is specified, delete the matching generations. When
2080 @var{pattern} specifies a duration, generations @emph{older} than the
2081 specified duration match. For instance, @code{--delete-generations=1m}
2082 deletes generations that are more than one month old.
2084 If the current generation matches, it is @emph{not} deleted. Also, the
2085 zeroth generation is never deleted.
2087 Note that deleting generations prevents rolling back to them.
2088 Consequently, this command must be used with care.
2092 Finally, since @command{guix package} may actually start build
2093 processes, it supports all the common build options (@pxref{Common Build
2094 Options}). It also supports package transformation options, such as
2095 @option{--with-source} (@pxref{Package Transformation Options}).
2096 However, note that package transformations are lost when upgrading; to
2097 preserve transformations across upgrades, you should define your own
2098 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2099 (@pxref{Defining Packages}).
2103 @section Substitutes
2106 @cindex pre-built binaries
2107 Guix supports transparent source/binary deployment, which means that it
2108 can either build things locally, or download pre-built items from a
2109 server. We call these pre-built items @dfn{substitutes}---they are
2110 substitutes for local build results. In many cases, downloading a
2111 substitute is much faster than building things locally.
2113 Substitutes can be anything resulting from a derivation build
2114 (@pxref{Derivations}). Of course, in the common case, they are
2115 pre-built package binaries, but source tarballs, for instance, which
2116 also result from derivation builds, can be available as substitutes.
2118 The @code{hydra.gnu.org} server is a front-end to a build farm that
2119 builds packages from the GNU distribution continuously for some
2120 architectures, and makes them available as substitutes. This is the
2121 default source of substitutes; it can be overridden by passing the
2122 @option{--substitute-urls} option either to @command{guix-daemon}
2123 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2124 or to client tools such as @command{guix package}
2125 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2128 Substitute URLs can be either HTTP or HTTPS.
2129 HTTPS is recommended because communications are encrypted; conversely,
2130 using HTTP makes all communications visible to an eavesdropper, who
2131 could use the information gathered to determine, for instance, whether
2132 your system has unpatched security vulnerabilities.
2135 @cindex digital signatures
2136 @cindex substitutes, authorization thereof
2137 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2139 must add its public key to the access control list (ACL) of archive
2140 imports, using the @command{guix archive} command (@pxref{Invoking guix
2141 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2142 be compromised and to serve genuine substitutes.
2144 This public key is installed along with Guix, in
2145 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2146 the installation prefix of Guix. If you installed Guix from source,
2147 make sure you checked the GPG signature of
2148 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2149 Then, you can run something like this:
2152 # guix archive --authorize < hydra.gnu.org.pub
2155 Once this is in place, the output of a command like @code{guix build}
2156 should change from something like:
2159 $ guix build emacs --dry-run
2160 The following derivations would be built:
2161 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2162 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2163 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2164 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2172 $ guix build emacs --dry-run
2173 The following files would be downloaded:
2174 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2175 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2176 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2177 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2182 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2183 will be downloaded, when possible, for future builds.
2185 Guix ignores substitutes that are not signed, or that are not signed by
2186 one of the keys listed in the ACL. It also detects and raises an error
2187 when attempting to use a substitute that has been tampered with.
2190 Substitutes are downloaded over HTTP or HTTPS.
2191 The @code{http_proxy} environment
2192 variable can be set in the environment of @command{guix-daemon} and is
2193 honored for downloads of substitutes. Note that the value of
2194 @code{http_proxy} in the environment where @command{guix build},
2195 @command{guix package}, and other client commands are run has
2196 @emph{absolutely no effect}.
2198 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2199 (in other words, the server is not authenticated), contrary to what
2200 HTTPS clients such as Web browsers usually do. This is because Guix
2201 authenticates substitute information itself, as explained above, which
2202 is what we care about (whereas X.509 certificates are about
2203 authenticating bindings between domain names and public keys.)
2205 You can get statistics on the substitutes provided by a server using the
2206 @command{guix weather} command (@pxref{Invoking guix weather}).
2208 The substitute mechanism can be disabled globally by running
2209 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2210 guix-daemon}). It can also be disabled temporarily by passing the
2211 @code{--no-substitutes} option to @command{guix package}, @command{guix
2212 build}, and other command-line tools.
2215 @unnumberedsubsec On Trusting Binaries
2217 Today, each individual's control over their own computing is at the
2218 mercy of institutions, corporations, and groups with enough power and
2219 determination to subvert the computing infrastructure and exploit its
2220 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2221 convenient, we encourage users to also build on their own, or even run
2222 their own build farm, such that @code{hydra.gnu.org} is less of an
2223 interesting target. One way to help is by publishing the software you
2224 build using @command{guix publish} so that others have one more choice
2225 of server to download substitutes from (@pxref{Invoking guix publish}).
2227 Guix has the foundations to maximize build reproducibility
2228 (@pxref{Features}). In most cases, independent builds of a given
2229 package or derivation should yield bit-identical results. Thus, through
2230 a diverse set of independent package builds, we can strengthen the
2231 integrity of our systems. The @command{guix challenge} command aims to
2232 help users assess substitute servers, and to assist developers in
2233 finding out about non-deterministic package builds (@pxref{Invoking guix
2234 challenge}). Similarly, the @option{--check} option of @command{guix
2235 build} allows users to check whether previously-installed substitutes
2236 are genuine by rebuilding them locally (@pxref{build-check,
2237 @command{guix build --check}}).
2239 In the future, we want Guix to have support to publish and retrieve
2240 binaries to/from other users, in a peer-to-peer fashion. If you would
2241 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2244 @node Packages with Multiple Outputs
2245 @section Packages with Multiple Outputs
2247 @cindex multiple-output packages
2248 @cindex package outputs
2251 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2252 source package leads to exactly one directory in the store. When running
2253 @command{guix package -i glibc}, one installs the default output of the
2254 GNU libc package; the default output is called @code{out}, but its name
2255 can be omitted as shown in this command. In this particular case, the
2256 default output of @code{glibc} contains all the C header files, shared
2257 libraries, static libraries, Info documentation, and other supporting
2260 Sometimes it is more appropriate to separate the various types of files
2261 produced from a single source package into separate outputs. For
2262 instance, the GLib C library (used by GTK+ and related packages)
2263 installs more than 20 MiB of reference documentation as HTML pages.
2264 To save space for users who do not need it, the documentation goes to a
2265 separate output, called @code{doc}. To install the main GLib output,
2266 which contains everything but the documentation, one would run:
2269 guix package -i glib
2272 @cindex documentation
2273 The command to install its documentation is:
2276 guix package -i glib:doc
2279 Some packages install programs with different ``dependency footprints''.
2280 For instance, the WordNet package installs both command-line tools and
2281 graphical user interfaces (GUIs). The former depend solely on the C
2282 library, whereas the latter depend on Tcl/Tk and the underlying X
2283 libraries. In this case, we leave the command-line tools in the default
2284 output, whereas the GUIs are in a separate output. This allows users
2285 who do not need the GUIs to save space. The @command{guix size} command
2286 can help find out about such situations (@pxref{Invoking guix size}).
2287 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2289 There are several such multiple-output packages in the GNU distribution.
2290 Other conventional output names include @code{lib} for libraries and
2291 possibly header files, @code{bin} for stand-alone programs, and
2292 @code{debug} for debugging information (@pxref{Installing Debugging
2293 Files}). The outputs of a packages are listed in the third column of
2294 the output of @command{guix package --list-available} (@pxref{Invoking
2298 @node Invoking guix gc
2299 @section Invoking @command{guix gc}
2301 @cindex garbage collector
2303 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2304 The @command{guix gc} command allows users to explicitly run the garbage
2305 collector to reclaim space from the @file{/gnu/store} directory. It is
2306 the @emph{only} way to remove files from @file{/gnu/store}---removing
2307 files or directories manually may break it beyond repair!
2309 The garbage collector has a set of known @dfn{roots}: any file under
2310 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2311 cannot be deleted; any other file is considered @dfn{dead} and may be
2312 deleted. The set of garbage collector roots includes default user
2313 profiles, and may be augmented with @command{guix build --root}, for
2314 example (@pxref{Invoking guix build}).
2316 Prior to running @code{guix gc --collect-garbage} to make space, it is
2317 often useful to remove old generations from user profiles; that way, old
2318 package builds referenced by those generations can be reclaimed. This
2319 is achieved by running @code{guix package --delete-generations}
2320 (@pxref{Invoking guix package}).
2322 Our recommendation is to run a garbage collection periodically, or when
2323 you are short on disk space. For instance, to guarantee that at least
2324 5@tie{}GB are available on your disk, simply run:
2330 It is perfectly safe to run as a non-interactive periodic job
2331 (@pxref{Scheduled Job Execution}, for how to set up such a job on
2332 GuixSD). Running @command{guix gc} with no arguments will collect as
2333 much garbage as it can, but that is often inconvenient: you may find
2334 yourself having to rebuild or re-download software that is ``dead'' from
2335 the GC viewpoint but that is necessary to build other pieces of
2336 software---e.g., the compiler tool chain.
2338 The @command{guix gc} command has three modes of operation: it can be
2339 used to garbage-collect any dead files (the default), to delete specific
2340 files (the @code{--delete} option), to print garbage-collector
2341 information, or for more advanced queries. The garbage collection
2342 options are as follows:
2345 @item --collect-garbage[=@var{min}]
2346 @itemx -C [@var{min}]
2347 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2348 sub-directories. This is the default operation when no option is
2351 When @var{min} is given, stop once @var{min} bytes have been collected.
2352 @var{min} may be a number of bytes, or it may include a unit as a
2353 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2354 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2356 When @var{min} is omitted, collect all the garbage.
2358 @item --free-space=@var{free}
2359 @itemx -F @var{free}
2360 Collect garbage until @var{free} space is available under
2361 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2362 as @code{500MiB}, as described above.
2364 When @var{free} or more is already available in @file{/gnu/store}, do
2365 nothing and exit immediately.
2369 Attempt to delete all the store files and directories specified as
2370 arguments. This fails if some of the files are not in the store, or if
2371 they are still live.
2373 @item --list-failures
2374 List store items corresponding to cached build failures.
2376 This prints nothing unless the daemon was started with
2377 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2378 @option{--cache-failures}}).
2380 @item --clear-failures
2381 Remove the specified store items from the failed-build cache.
2383 Again, this option only makes sense when the daemon is started with
2384 @option{--cache-failures}. Otherwise, it does nothing.
2387 Show the list of dead files and directories still present in the
2388 store---i.e., files and directories no longer reachable from any root.
2391 Show the list of live store files and directories.
2395 In addition, the references among existing store files can be queried:
2401 @cindex package dependencies
2402 List the references (respectively, the referrers) of store files given
2408 List the requisites of the store files passed as arguments. Requisites
2409 include the store files themselves, their references, and the references
2410 of these, recursively. In other words, the returned list is the
2411 @dfn{transitive closure} of the store files.
2413 @xref{Invoking guix size}, for a tool to profile the size of the closure
2414 of an element. @xref{Invoking guix graph}, for a tool to visualize
2415 the graph of references.
2419 Lastly, the following options allow you to check the integrity of the
2420 store and to control disk usage.
2424 @item --verify[=@var{options}]
2425 @cindex integrity, of the store
2426 @cindex integrity checking
2427 Verify the integrity of the store.
2429 By default, make sure that all the store items marked as valid in the
2430 database of the daemon actually exist in @file{/gnu/store}.
2432 When provided, @var{options} must be a comma-separated list containing one
2433 or more of @code{contents} and @code{repair}.
2435 When passing @option{--verify=contents}, the daemon computes the
2436 content hash of each store item and compares it against its hash in the
2437 database. Hash mismatches are reported as data corruptions. Because it
2438 traverses @emph{all the files in the store}, this command can take a
2439 long time, especially on systems with a slow disk drive.
2441 @cindex repairing the store
2442 @cindex corruption, recovering from
2443 Using @option{--verify=repair} or @option{--verify=contents,repair}
2444 causes the daemon to try to repair corrupt store items by fetching
2445 substitutes for them (@pxref{Substitutes}). Because repairing is not
2446 atomic, and thus potentially dangerous, it is available only to the
2447 system administrator. A lightweight alternative, when you know exactly
2448 which items in the store are corrupt, is @command{guix build --repair}
2449 (@pxref{Invoking guix build}).
2452 @cindex deduplication
2453 Optimize the store by hard-linking identical files---this is
2454 @dfn{deduplication}.
2456 The daemon performs deduplication after each successful build or archive
2457 import, unless it was started with @code{--disable-deduplication}
2458 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2459 this option is primarily useful when the daemon was running with
2460 @code{--disable-deduplication}.
2464 @node Invoking guix pull
2465 @section Invoking @command{guix pull}
2467 @cindex upgrading Guix
2468 @cindex updating Guix
2469 @cindex @command{guix pull}
2471 Packages are installed or upgraded to the latest version available in
2472 the distribution currently available on your local machine. To update
2473 that distribution, along with the Guix tools, you must run @command{guix
2474 pull}: the command downloads the latest Guix source code and package
2475 descriptions, and deploys it.
2477 On completion, @command{guix package} will use packages and package
2478 versions from this just-retrieved copy of Guix. Not only that, but all
2479 the Guix commands and Scheme modules will also be taken from that latest
2480 version. New @command{guix} sub-commands added by the update also
2483 Any user can update their Guix copy using @command{guix pull}, and the
2484 effect is limited to the user who run @command{guix pull}. For
2485 instance, when user @code{root} runs @command{guix pull}, this has no
2486 effect on the version of Guix that user @code{alice} sees, and vice
2487 versa@footnote{Under the hood, @command{guix pull} updates the
2488 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2489 and the @command{guix} command loads code from there. Currently, the
2490 only way to roll back an invocation of @command{guix pull} is to
2491 manually update this symlink to point to the previous Guix.}.
2493 The @command{guix pull} command is usually invoked with no arguments,
2494 but it supports the following options:
2498 Produce verbose output, writing build logs to the standard error output.
2500 @item --url=@var{url}
2501 Download the source tarball of Guix from @var{url}.
2503 By default, the tarball is taken from its canonical address at
2504 @code{gnu.org}, for the stable branch of Guix.
2506 With some Git servers, this can be used to deploy any version of Guix.
2507 For example, to download and deploy version 0.12.0 of Guix from the
2511 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2514 It can also be used to deploy arbitrary Git revisions:
2517 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2521 Use the bootstrap Guile to build the latest Guix. This option is only
2522 useful to Guix developers.
2525 In addition, @command{guix pull} supports all the common build options
2526 (@pxref{Common Build Options}).
2528 @node Invoking guix pack
2529 @section Invoking @command{guix pack}
2531 Occasionally you want to pass software to people who are not (yet!)
2532 lucky enough to be using Guix. You'd tell them to run @command{guix
2533 package -i @var{something}}, but that's not possible in this case. This
2534 is where @command{guix pack} comes in.
2538 @cindex application bundle
2539 @cindex software bundle
2540 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2541 @dfn{software bundle}: it creates a tarball or some other archive
2542 containing the binaries of the software you're interested in, and all
2543 its dependencies. The resulting archive can be used on any machine that
2544 does not have Guix, and people can run the exact same binaries as those
2545 you have with Guix. The pack itself is created in a bit-reproducible
2546 fashion, so anyone can verify that it really contains the build results
2547 that you pretend to be shipping.
2549 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2550 their dependencies, you can run:
2553 $ guix pack guile emacs geiser
2555 /gnu/store/@dots{}-pack.tar.gz
2558 The result here is a tarball containing a @file{/gnu/store} directory
2559 with all the relevant packages. The resulting tarball contains a
2560 @dfn{profile} with the three packages of interest; the profile is the
2561 same as would be created by @command{guix package -i}. It is this
2562 mechanism that is used to create Guix's own standalone binary tarball
2563 (@pxref{Binary Installation}).
2565 Users of this pack would have to run
2566 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2567 find inconvenient. To work around it, you can create, say, a
2568 @file{/opt/gnu/bin} symlink to the profile:
2571 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2575 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2577 Alternatively, you can produce a pack in the Docker image format using
2578 the following command:
2581 guix pack -f docker guile emacs geiser
2585 The result is a tarball that can be passed to the @command{docker load}
2587 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2588 documentation} for more information.
2590 Several command-line options allow you to customize your pack:
2593 @item --format=@var{format}
2594 @itemx -f @var{format}
2595 Produce a pack in the given @var{format}.
2597 The available formats are:
2601 This is the default format. It produces a tarball containing all the
2602 specifies binaries and symlinks.
2605 This produces a tarball that follows the
2606 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2607 Docker Image Specification}.
2610 @item --expression=@var{expr}
2611 @itemx -e @var{expr}
2612 Consider the package @var{expr} evaluates to.
2614 This has the same purpose as the same-named option in @command{guix
2615 build} (@pxref{Additional Build Options, @code{--expression} in
2616 @command{guix build}}).
2618 @item --system=@var{system}
2619 @itemx -s @var{system}
2620 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2621 the system type of the build host.
2623 @item --target=@var{triplet}
2624 @cindex cross-compilation
2625 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2626 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2627 configuration triplets,, autoconf, Autoconf}).
2629 @item --compression=@var{tool}
2630 @itemx -C @var{tool}
2631 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2632 @code{bzip2}, @code{xz}, or @code{lzip}.
2634 @item --symlink=@var{spec}
2635 @itemx -S @var{spec}
2636 Add the symlinks specified by @var{spec} to the pack. This option can
2637 appear several times.
2639 @var{spec} has the form @code{@var{source}=@var{target}}, where
2640 @var{source} is the symlink that will be created and @var{target} is the
2643 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2644 symlink pointing to the @file{bin} sub-directory of the profile.
2646 @item --localstatedir
2647 Include the ``local state directory'', @file{/var/guix}, in the
2650 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2651 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2652 the pack means that the store is ``complete'' and manageable by Guix;
2653 not providing it pack means that the store is ``dead'': items cannot be
2654 added to it or removed from it after extraction of the pack.
2656 One use case for this is the Guix self-contained binary tarball
2657 (@pxref{Binary Installation}).
2660 In addition, @command{guix pack} supports all the common build options
2661 (@pxref{Common Build Options}) and all the package transformation
2662 options (@pxref{Package Transformation Options}).
2665 @node Invoking guix archive
2666 @section Invoking @command{guix archive}
2668 @cindex @command{guix archive}
2670 The @command{guix archive} command allows users to @dfn{export} files
2671 from the store into a single archive, and to later @dfn{import} them.
2672 In particular, it allows store files to be transferred from one machine
2673 to the store on another machine.
2675 @cindex exporting store items
2676 To export store files as an archive to standard output, run:
2679 guix archive --export @var{options} @var{specifications}...
2682 @var{specifications} may be either store file names or package
2683 specifications, as for @command{guix package} (@pxref{Invoking guix
2684 package}). For instance, the following command creates an archive
2685 containing the @code{gui} output of the @code{git} package and the main
2686 output of @code{emacs}:
2689 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2692 If the specified packages are not built yet, @command{guix archive}
2693 automatically builds them. The build process may be controlled with the
2694 common build options (@pxref{Common Build Options}).
2696 To transfer the @code{emacs} package to a machine connected over SSH,
2700 guix archive --export -r emacs | ssh the-machine guix archive --import
2704 Similarly, a complete user profile may be transferred from one machine
2705 to another like this:
2708 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2709 ssh the-machine guix-archive --import
2713 However, note that, in both examples, all of @code{emacs} and the
2714 profile as well as all of their dependencies are transferred (due to
2715 @code{-r}), regardless of what is already available in the store on the
2716 target machine. The @code{--missing} option can help figure out which
2717 items are missing from the target store. The @command{guix copy}
2718 command simplifies and optimizes this whole process, so this is probably
2719 what you should use in this case (@pxref{Invoking guix copy}).
2721 @cindex nar, archive format
2722 @cindex normalized archive (nar)
2723 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2724 comparable in spirit to `tar', but with differences
2725 that make it more appropriate for our purposes. First, rather than
2726 recording all Unix metadata for each file, the nar format only mentions
2727 the file type (regular, directory, or symbolic link); Unix permissions
2728 and owner/group are dismissed. Second, the order in which directory
2729 entries are stored always follows the order of file names according to
2730 the C locale collation order. This makes archive production fully
2733 When exporting, the daemon digitally signs the contents of the archive,
2734 and that digital signature is appended. When importing, the daemon
2735 verifies the signature and rejects the import in case of an invalid
2736 signature or if the signing key is not authorized.
2737 @c FIXME: Add xref to daemon doc about signatures.
2739 The main options are:
2743 Export the specified store files or packages (see below.) Write the
2744 resulting archive to the standard output.
2746 Dependencies are @emph{not} included in the output, unless
2747 @code{--recursive} is passed.
2751 When combined with @code{--export}, this instructs @command{guix
2752 archive} to include dependencies of the given items in the archive.
2753 Thus, the resulting archive is self-contained: it contains the closure
2754 of the exported store items.
2757 Read an archive from the standard input, and import the files listed
2758 therein into the store. Abort if the archive has an invalid digital
2759 signature, or if it is signed by a public key not among the authorized
2760 keys (see @code{--authorize} below.)
2763 Read a list of store file names from the standard input, one per line,
2764 and write on the standard output the subset of these files missing from
2767 @item --generate-key[=@var{parameters}]
2768 @cindex signing, archives
2769 Generate a new key pair for the daemon. This is a prerequisite before
2770 archives can be exported with @code{--export}. Note that this operation
2771 usually takes time, because it needs to gather enough entropy to
2772 generate the key pair.
2774 The generated key pair is typically stored under @file{/etc/guix}, in
2775 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2776 key, which must be kept secret.) When @var{parameters} is omitted,
2777 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2778 versions before 1.6.0, it is a 4096-bit RSA key.
2779 Alternatively, @var{parameters} can specify
2780 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2781 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2782 Libgcrypt Reference Manual}).
2785 @cindex authorizing, archives
2786 Authorize imports signed by the public key passed on standard input.
2787 The public key must be in ``s-expression advanced format''---i.e., the
2788 same format as the @file{signing-key.pub} file.
2790 The list of authorized keys is kept in the human-editable file
2791 @file{/etc/guix/acl}. The file contains
2792 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2793 s-expressions''} and is structured as an access-control list in the
2794 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2797 @item --extract=@var{directory}
2798 @itemx -x @var{directory}
2799 Read a single-item archive as served by substitute servers
2800 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2801 low-level operation needed in only very narrow use cases; see below.
2803 For example, the following command extracts the substitute for Emacs
2804 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2808 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2809 | bunzip2 | guix archive -x /tmp/emacs
2812 Single-item archives are different from multiple-item archives produced
2813 by @command{guix archive --export}; they contain a single store item,
2814 and they do @emph{not} embed a signature. Thus this operation does
2815 @emph{no} signature verification and its output should be considered
2818 The primary purpose of this operation is to facilitate inspection of
2819 archive contents coming from possibly untrusted substitute servers.
2823 @c *********************************************************************
2824 @node Programming Interface
2825 @chapter Programming Interface
2827 GNU Guix provides several Scheme programming interfaces (APIs) to
2828 define, build, and query packages. The first interface allows users to
2829 write high-level package definitions. These definitions refer to
2830 familiar packaging concepts, such as the name and version of a package,
2831 its build system, and its dependencies. These definitions can then be
2832 turned into concrete build actions.
2834 Build actions are performed by the Guix daemon, on behalf of users. In a
2835 standard setup, the daemon has write access to the store---the
2836 @file{/gnu/store} directory---whereas users do not. The recommended
2837 setup also has the daemon perform builds in chroots, under a specific
2838 build users, to minimize interference with the rest of the system.
2841 Lower-level APIs are available to interact with the daemon and the
2842 store. To instruct the daemon to perform a build action, users actually
2843 provide it with a @dfn{derivation}. A derivation is a low-level
2844 representation of the build actions to be taken, and the environment in
2845 which they should occur---derivations are to package definitions what
2846 assembly is to C programs. The term ``derivation'' comes from the fact
2847 that build results @emph{derive} from them.
2849 This chapter describes all these APIs in turn, starting from high-level
2850 package definitions.
2853 * Defining Packages:: Defining new packages.
2854 * Build Systems:: Specifying how packages are built.
2855 * The Store:: Manipulating the package store.
2856 * Derivations:: Low-level interface to package derivations.
2857 * The Store Monad:: Purely functional interface to the store.
2858 * G-Expressions:: Manipulating build expressions.
2861 @node Defining Packages
2862 @section Defining Packages
2864 The high-level interface to package definitions is implemented in the
2865 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2866 example, the package definition, or @dfn{recipe}, for the GNU Hello
2867 package looks like this:
2870 (define-module (gnu packages hello)
2871 #:use-module (guix packages)
2872 #:use-module (guix download)
2873 #:use-module (guix build-system gnu)
2874 #:use-module (guix licenses)
2875 #:use-module (gnu packages gawk))
2877 (define-public hello
2883 (uri (string-append "mirror://gnu/hello/hello-" version
2887 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2888 (build-system gnu-build-system)
2889 (arguments '(#:configure-flags '("--enable-silent-rules")))
2890 (inputs `(("gawk" ,gawk)))
2891 (synopsis "Hello, GNU world: An example GNU package")
2892 (description "Guess what GNU Hello prints!")
2893 (home-page "http://www.gnu.org/software/hello/")
2898 Without being a Scheme expert, the reader may have guessed the meaning
2899 of the various fields here. This expression binds the variable
2900 @code{hello} to a @code{<package>} object, which is essentially a record
2901 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2902 This package object can be inspected using procedures found in the
2903 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2904 returns---surprise!---@code{"hello"}.
2906 With luck, you may be able to import part or all of the definition of
2907 the package you are interested in from another repository, using the
2908 @code{guix import} command (@pxref{Invoking guix import}).
2910 In the example above, @var{hello} is defined in a module of its own,
2911 @code{(gnu packages hello)}. Technically, this is not strictly
2912 necessary, but it is convenient to do so: all the packages defined in
2913 modules under @code{(gnu packages @dots{})} are automatically known to
2914 the command-line tools (@pxref{Package Modules}).
2916 There are a few points worth noting in the above package definition:
2920 The @code{source} field of the package is an @code{<origin>} object
2921 (@pxref{origin Reference}, for the complete reference).
2922 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2923 meaning that the source is a file to be downloaded over FTP or HTTP.
2925 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2926 the GNU mirrors defined in @code{(guix download)}.
2928 The @code{sha256} field specifies the expected SHA256 hash of the file
2929 being downloaded. It is mandatory, and allows Guix to check the
2930 integrity of the file. The @code{(base32 @dots{})} form introduces the
2931 base32 representation of the hash. You can obtain this information with
2932 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2933 hash} (@pxref{Invoking guix hash}).
2936 When needed, the @code{origin} form can also have a @code{patches} field
2937 listing patches to be applied, and a @code{snippet} field giving a
2938 Scheme expression to modify the source code.
2941 @cindex GNU Build System
2942 The @code{build-system} field specifies the procedure to build the
2943 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2944 represents the familiar GNU Build System, where packages may be
2945 configured, built, and installed with the usual @code{./configure &&
2946 make && make check && make install} command sequence.
2949 The @code{arguments} field specifies options for the build system
2950 (@pxref{Build Systems}). Here it is interpreted by
2951 @var{gnu-build-system} as a request run @file{configure} with the
2952 @code{--enable-silent-rules} flag.
2958 What about these quote (@code{'}) characters? They are Scheme syntax to
2959 introduce a literal list; @code{'} is synonymous with @code{quote}.
2960 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2961 for details. Here the value of the @code{arguments} field is a list of
2962 arguments passed to the build system down the road, as with @code{apply}
2963 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2966 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2967 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2968 @code{#:configure-flags} is a keyword used to pass a keyword argument
2969 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2973 The @code{inputs} field specifies inputs to the build process---i.e.,
2974 build-time or run-time dependencies of the package. Here, we define an
2975 input called @code{"gawk"} whose value is that of the @var{gawk}
2976 variable; @var{gawk} is itself bound to a @code{<package>} object.
2978 @cindex backquote (quasiquote)
2981 @cindex comma (unquote)
2985 @findex unquote-splicing
2986 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2987 us to introduce a literal list in the @code{inputs} field, while
2988 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2989 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2992 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2993 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2994 of ensuring that they are present (@pxref{Build Systems}).
2996 However, any other dependencies need to be specified in the
2997 @code{inputs} field. Any dependency not specified here will simply be
2998 unavailable to the build process, possibly leading to a build failure.
3001 @xref{package Reference}, for a full description of possible fields.
3003 Once a package definition is in place, the
3004 package may actually be built using the @code{guix build} command-line
3005 tool (@pxref{Invoking guix build}), troubleshooting any build failures
3006 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
3007 package definition using the @command{guix edit} command
3008 (@pxref{Invoking guix edit}).
3009 @xref{Packaging Guidelines}, for
3010 more information on how to test package definitions, and
3011 @ref{Invoking guix lint}, for information on how to check a definition
3012 for style conformance.
3013 @vindex GUIX_PACKAGE_PATH
3014 Lastly, @pxref{Package Modules}, for information
3015 on how to extend the distribution by adding your own package definitions
3016 to @code{GUIX_PACKAGE_PATH}.
3018 Finally, updating the package definition to a new upstream version
3019 can be partly automated by the @command{guix refresh} command
3020 (@pxref{Invoking guix refresh}).
3022 Behind the scenes, a derivation corresponding to the @code{<package>}
3023 object is first computed by the @code{package-derivation} procedure.
3024 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
3025 The build actions it prescribes may then be realized by using the
3026 @code{build-derivations} procedure (@pxref{The Store}).
3028 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
3029 Return the @code{<derivation>} object of @var{package} for @var{system}
3030 (@pxref{Derivations}).
3032 @var{package} must be a valid @code{<package>} object, and @var{system}
3033 must be a string denoting the target system type---e.g.,
3034 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
3035 must be a connection to the daemon, which operates on the store
3036 (@pxref{The Store}).
3040 @cindex cross-compilation
3041 Similarly, it is possible to compute a derivation that cross-builds a
3042 package for some other system:
3044 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
3045 @var{package} @var{target} [@var{system}]
3046 Return the @code{<derivation>} object of @var{package} cross-built from
3047 @var{system} to @var{target}.
3049 @var{target} must be a valid GNU triplet denoting the target hardware
3050 and operating system, such as @code{"mips64el-linux-gnu"}
3051 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
3052 Configure and Build System}).
3055 @cindex package transformations
3056 @cindex input rewriting
3057 @cindex dependency tree rewriting
3058 Packages can be manipulated in arbitrary ways. An example of a useful
3059 transformation is @dfn{input rewriting}, whereby the dependency tree of
3060 a package is rewritten by replacing specific inputs by others:
3062 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
3063 [@var{rewrite-name}]
3064 Return a procedure that, when passed a package, replaces its direct and
3065 indirect dependencies (but not its implicit inputs) according to
3066 @var{replacements}. @var{replacements} is a list of package pairs; the
3067 first element of each pair is the package to replace, and the second one
3070 Optionally, @var{rewrite-name} is a one-argument procedure that takes
3071 the name of a package and returns its new name after rewrite.
3075 Consider this example:
3078 (define libressl-instead-of-openssl
3079 ;; This is a procedure to replace OPENSSL by LIBRESSL,
3081 (package-input-rewriting `((,openssl . ,libressl))))
3083 (define git-with-libressl
3084 (libressl-instead-of-openssl git))
3088 Here we first define a rewriting procedure that replaces @var{openssl}
3089 with @var{libressl}. Then we use it to define a @dfn{variant} of the
3090 @var{git} package that uses @var{libressl} instead of @var{openssl}.
3091 This is exactly what the @option{--with-input} command-line option does
3092 (@pxref{Package Transformation Options, @option{--with-input}}).
3094 A more generic procedure to rewrite a package dependency graph is
3095 @code{package-mapping}: it supports arbitrary changes to nodes in the
3098 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
3099 Return a procedure that, given a package, applies @var{proc} to all the packages
3100 depended on and returns the resulting package. The procedure stops recursion
3101 when @var{cut?} returns true for a given package.
3105 * package Reference :: The package data type.
3106 * origin Reference:: The origin data type.
3110 @node package Reference
3111 @subsection @code{package} Reference
3113 This section summarizes all the options available in @code{package}
3114 declarations (@pxref{Defining Packages}).
3116 @deftp {Data Type} package
3117 This is the data type representing a package recipe.
3121 The name of the package, as a string.
3123 @item @code{version}
3124 The version of the package, as a string.
3127 An object telling how the source code for the package should be
3128 acquired. Most of the time, this is an @code{origin} object, which
3129 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3130 can also be any other ``file-like'' object such as a @code{local-file},
3131 which denotes a file from the local file system (@pxref{G-Expressions,
3132 @code{local-file}}).
3134 @item @code{build-system}
3135 The build system that should be used to build the package (@pxref{Build
3138 @item @code{arguments} (default: @code{'()})
3139 The arguments that should be passed to the build system. This is a
3140 list, typically containing sequential keyword-value pairs.
3142 @item @code{inputs} (default: @code{'()})
3143 @itemx @code{native-inputs} (default: @code{'()})
3144 @itemx @code{propagated-inputs} (default: @code{'()})
3145 @cindex inputs, of packages
3146 These fields list dependencies of the package. Each one is a list of
3147 tuples, where each tuple has a label for the input (a string) as its
3148 first element, a package, origin, or derivation as its second element,
3149 and optionally the name of the output thereof that should be used, which
3150 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3151 more on package outputs). For example, the list below specifies three
3155 `(("libffi" ,libffi)
3156 ("libunistring" ,libunistring)
3157 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3160 @cindex cross compilation, package dependencies
3161 The distinction between @code{native-inputs} and @code{inputs} is
3162 necessary when considering cross-compilation. When cross-compiling,
3163 dependencies listed in @code{inputs} are built for the @emph{target}
3164 architecture; conversely, dependencies listed in @code{native-inputs}
3165 are built for the architecture of the @emph{build} machine.
3167 @code{native-inputs} is typically used to list tools needed at
3168 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3169 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3170 this area (@pxref{Invoking guix lint}).
3172 @anchor{package-propagated-inputs}
3173 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3174 specified packages will be automatically installed alongside the package
3175 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3176 package}}, for information on how @command{guix package} deals with
3179 For example this is necessary when a C/C++ library needs headers of
3180 another library to compile, or when a pkg-config file refers to another
3181 one @i{via} its @code{Requires} field.
3183 Another example where @code{propagated-inputs} is useful is for languages
3184 that lack a facility to record the run-time search path akin to the
3185 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3186 more. To ensure that libraries written in those languages can find
3187 library code they depend on at run time, run-time dependencies must be
3188 listed in @code{propagated-inputs} rather than @code{inputs}.
3190 @item @code{self-native-input?} (default: @code{#f})
3191 This is a Boolean field telling whether the package should use itself as
3192 a native input when cross-compiling.
3194 @item @code{outputs} (default: @code{'("out")})
3195 The list of output names of the package. @xref{Packages with Multiple
3196 Outputs}, for typical uses of additional outputs.
3198 @item @code{native-search-paths} (default: @code{'()})
3199 @itemx @code{search-paths} (default: @code{'()})
3200 A list of @code{search-path-specification} objects describing
3201 search-path environment variables honored by the package.
3203 @item @code{replacement} (default: @code{#f})
3204 This must be either @code{#f} or a package object that will be used as a
3205 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3208 @item @code{synopsis}
3209 A one-line description of the package.
3211 @item @code{description}
3212 A more elaborate description of the package.
3214 @item @code{license}
3215 @cindex license, of packages
3216 The license of the package; a value from @code{(guix licenses)},
3217 or a list of such values.
3219 @item @code{home-page}
3220 The URL to the home-page of the package, as a string.
3222 @item @code{supported-systems} (default: @var{%supported-systems})
3223 The list of systems supported by the package, as strings of the form
3224 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3226 @item @code{maintainers} (default: @code{'()})
3227 The list of maintainers of the package, as @code{maintainer} objects.
3229 @item @code{location} (default: source location of the @code{package} form)
3230 The source location of the package. It is useful to override this when
3231 inheriting from another package, in which case this field is not
3232 automatically corrected.
3237 @node origin Reference
3238 @subsection @code{origin} Reference
3240 This section summarizes all the options available in @code{origin}
3241 declarations (@pxref{Defining Packages}).
3243 @deftp {Data Type} origin
3244 This is the data type representing a source code origin.
3248 An object containing the URI of the source. The object type depends on
3249 the @code{method} (see below). For example, when using the
3250 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3251 values are: a URL represented as a string, or a list thereof.
3254 A procedure that handles the URI.
3259 @item @var{url-fetch} from @code{(guix download)}
3260 download a file from the HTTP, HTTPS, or FTP URL specified in the
3264 @item @var{git-fetch} from @code{(guix git-download)}
3265 clone the Git version control repository, and check out the revision
3266 specified in the @code{uri} field as a @code{git-reference} object; a
3267 @code{git-reference} looks like this:
3271 (url "git://git.debian.org/git/pkg-shadow/shadow")
3272 (commit "v4.1.5.1"))
3277 A bytevector containing the SHA-256 hash of the source. Typically the
3278 @code{base32} form is used here to generate the bytevector from a
3281 You can obtain this information using @code{guix download}
3282 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3285 @item @code{file-name} (default: @code{#f})
3286 The file name under which the source code should be saved. When this is
3287 @code{#f}, a sensible default value will be used in most cases. In case
3288 the source is fetched from a URL, the file name from the URL will be
3289 used. For version control checkouts, it is recommended to provide the
3290 file name explicitly because the default is not very descriptive.
3292 @item @code{patches} (default: @code{'()})
3293 A list of file names containing patches to be applied to the source.
3295 This list of patches must be unconditional. In particular, it cannot
3296 depend on the value of @code{%current-system} or
3297 @code{%current-target-system}.
3299 @item @code{snippet} (default: @code{#f})
3300 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3301 in the source directory. This is a convenient way to modify the source,
3302 sometimes more convenient than a patch.
3304 @item @code{patch-flags} (default: @code{'("-p1")})
3305 A list of command-line flags that should be passed to the @code{patch}
3308 @item @code{patch-inputs} (default: @code{#f})
3309 Input packages or derivations to the patching process. When this is
3310 @code{#f}, the usual set of inputs necessary for patching are provided,
3311 such as GNU@tie{}Patch.
3313 @item @code{modules} (default: @code{'()})
3314 A list of Guile modules that should be loaded during the patching
3315 process and while running the code in the @code{snippet} field.
3317 @item @code{patch-guile} (default: @code{#f})
3318 The Guile package that should be used in the patching process. When
3319 this is @code{#f}, a sensible default is used.
3325 @section Build Systems
3327 @cindex build system
3328 Each package definition specifies a @dfn{build system} and arguments for
3329 that build system (@pxref{Defining Packages}). This @code{build-system}
3330 field represents the build procedure of the package, as well as implicit
3331 dependencies of that build procedure.
3333 Build systems are @code{<build-system>} objects. The interface to
3334 create and manipulate them is provided by the @code{(guix build-system)}
3335 module, and actual build systems are exported by specific modules.
3337 @cindex bag (low-level package representation)
3338 Under the hood, build systems first compile package objects to
3339 @dfn{bags}. A @dfn{bag} is like a package, but with less
3340 ornamentation---in other words, a bag is a lower-level representation of
3341 a package, which includes all the inputs of that package, including some
3342 that were implicitly added by the build system. This intermediate
3343 representation is then compiled to a derivation (@pxref{Derivations}).
3345 Build systems accept an optional list of @dfn{arguments}. In package
3346 definitions, these are passed @i{via} the @code{arguments} field
3347 (@pxref{Defining Packages}). They are typically keyword arguments
3348 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3349 Guile Reference Manual}). The value of these arguments is usually
3350 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3351 by the daemon (@pxref{Derivations}).
3353 The main build system is @var{gnu-build-system}, which implements the
3354 standard build procedure for GNU and many other packages. It
3355 is provided by the @code{(guix build-system gnu)} module.
3357 @defvr {Scheme Variable} gnu-build-system
3358 @var{gnu-build-system} represents the GNU Build System, and variants
3359 thereof (@pxref{Configuration, configuration and makefile conventions,,
3360 standards, GNU Coding Standards}).
3362 @cindex build phases
3363 In a nutshell, packages using it are configured, built, and installed with
3364 the usual @code{./configure && make && make check && make install}
3365 command sequence. In practice, a few additional steps are often needed.
3366 All these steps are split up in separate @dfn{phases},
3367 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3368 modules for more details about the build phases.}:
3372 Unpack the source tarball, and change the current directory to the
3373 extracted source tree. If the source is actually a directory, copy it
3374 to the build tree, and enter that directory.
3376 @item patch-source-shebangs
3377 Patch shebangs encountered in source files so they refer to the right
3378 store file names. For instance, this changes @code{#!/bin/sh} to
3379 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3382 Run the @file{configure} script with a number of default options, such
3383 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3384 by the @code{#:configure-flags} argument.
3387 Run @code{make} with the list of flags specified with
3388 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3389 (the default), build with @code{make -j}.
3392 Run @code{make check}, or some other target specified with
3393 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3394 @code{#:parallel-tests?} argument is true (the default), run @code{make
3398 Run @code{make install} with the flags listed in @code{#:make-flags}.
3400 @item patch-shebangs
3401 Patch shebangs on the installed executable files.
3404 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3405 is false), copying them to the @code{debug} output when available
3406 (@pxref{Installing Debugging Files}).
3409 @vindex %standard-phases
3410 The build-side module @code{(guix build gnu-build-system)} defines
3411 @var{%standard-phases} as the default list of build phases.
3412 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3413 procedure implements the actual phase.
3415 The list of phases used for a particular package can be changed with the
3416 @code{#:phases} parameter. For instance, passing:
3419 #:phases (modify-phases %standard-phases (delete 'configure))
3422 means that all the phases described above will be used, except the
3423 @code{configure} phase.
3425 In addition, this build system ensures that the ``standard'' environment
3426 for GNU packages is available. This includes tools such as GCC, libc,
3427 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3428 build-system gnu)} module for a complete list). We call these the
3429 @dfn{implicit inputs} of a package, because package definitions do not
3430 have to mention them.
3433 Other @code{<build-system>} objects are defined to support other
3434 conventions and tools used by free software packages. They inherit most
3435 of @var{gnu-build-system}, and differ mainly in the set of inputs
3436 implicitly added to the build process, and in the list of phases
3437 executed. Some of these build systems are listed below.
3439 @defvr {Scheme Variable} ant-build-system
3440 This variable is exported by @code{(guix build-system ant)}. It
3441 implements the build procedure for Java packages that can be built with
3442 @url{http://ant.apache.org/, Ant build tool}.
3444 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3445 provided by the @code{icedtea} package to the set of inputs. Different
3446 packages can be specified with the @code{#:ant} and @code{#:jdk}
3447 parameters, respectively.
3449 When the original package does not provide a suitable Ant build file,
3450 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3451 build file @file{build.xml} with tasks to build the specified jar
3452 archive. In this case the parameter @code{#:source-dir} can be used to
3453 specify the source sub-directory, defaulting to ``src''.
3455 The parameter @code{#:build-target} can be used to specify the Ant task
3456 that should be run during the @code{build} phase. By default the
3457 ``jar'' task will be run.
3461 @defvr {Scheme Variable} asdf-build-system/source
3462 @defvrx {Scheme Variable} asdf-build-system/sbcl
3463 @defvrx {Scheme Variable} asdf-build-system/ecl
3465 These variables, exported by @code{(guix build-system asdf)}, implement
3466 build procedures for Common Lisp packages using
3467 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3468 definition facility for Common Lisp programs and libraries.
3470 The @code{asdf-build-system/source} system installs the packages in
3471 source form, and can be loaded using any common lisp implementation, via
3472 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3473 systems in the format which a particular implementation understands.
3474 These build systems can also be used to produce executable programs, or
3475 lisp images which contain a set of packages pre-loaded.
3477 The build system uses naming conventions. For binary packages, the
3478 package name should be prefixed with the lisp implementation, such as
3479 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3481 Additionally, the corresponding source package should be labeled using
3482 the same convention as python packages (see @ref{Python Modules}), using
3483 the @code{cl-} prefix.
3485 For binary packages, each system should be defined as a Guix package.
3486 If one package @code{origin} contains several systems, package variants
3487 can be created in order to build all the systems. Source packages,
3488 which use @code{asdf-build-system/source}, may contain several systems.
3490 In order to create executable programs and images, the build-side
3491 procedures @code{build-program} and @code{build-image} can be used.
3492 They should be called in a build phase after the @code{create-symlinks}
3493 phase, so that the system which was just built can be used within the
3494 resulting image. @code{build-program} requires a list of Common Lisp
3495 expressions to be passed as the @code{#:entry-program} argument.
3497 If the system is not defined within its own @code{.asd} file of the same
3498 name, then the @code{#:asd-file} parameter should be used to specify
3499 which file the system is defined in. Furthermore, if the package
3500 defines a system for its tests in a separate file, it will be loaded
3501 before the tests are run if it is specified by the
3502 @code{#:test-asd-file} parameter. If it is not set, the files
3503 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3504 and @code{test.asd} will be tried if they exist.
3506 If for some reason the package must be named in a different way than the
3507 naming conventions suggest, the @code{#:asd-system-name} parameter can
3508 be used to specify the name of the system.
3512 @defvr {Scheme Variable} cargo-build-system
3513 @cindex Rust programming language
3514 @cindex Cargo (Rust build system)
3515 This variable is exported by @code{(guix build-system cargo)}. It
3516 supports builds of packages using Cargo, the build tool of the
3517 @uref{https://www.rust-lang.org, Rust programming language}.
3519 In its @code{configure} phase, this build system replaces dependencies
3520 specified in the @file{Carto.toml} file with inputs to the Guix package.
3521 The @code{install} phase installs the binaries, and it also installs the
3522 source code and @file{Cargo.toml} file.
3525 @defvr {Scheme Variable} cmake-build-system
3526 This variable is exported by @code{(guix build-system cmake)}. It
3527 implements the build procedure for packages using the
3528 @url{http://www.cmake.org, CMake build tool}.
3530 It automatically adds the @code{cmake} package to the set of inputs.
3531 Which package is used can be specified with the @code{#:cmake}
3534 The @code{#:configure-flags} parameter is taken as a list of flags
3535 passed to the @command{cmake} command. The @code{#:build-type}
3536 parameter specifies in abstract terms the flags passed to the compiler;
3537 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3538 debugging information''), which roughly means that code is compiled with
3539 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3542 @defvr {Scheme Variable} glib-or-gtk-build-system
3543 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3544 is intended for use with packages making use of GLib or GTK+.
3546 This build system adds the following two phases to the ones defined by
3547 @var{gnu-build-system}:
3550 @item glib-or-gtk-wrap
3551 The phase @code{glib-or-gtk-wrap} ensures that programs in
3552 @file{bin/} are able to find GLib ``schemas'' and
3553 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3554 modules}. This is achieved by wrapping the programs in launch scripts
3555 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3556 environment variables.
3558 It is possible to exclude specific package outputs from that wrapping
3559 process by listing their names in the
3560 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3561 when an output is known not to contain any GLib or GTK+ binaries, and
3562 where wrapping would gratuitously add a dependency of that output on
3565 @item glib-or-gtk-compile-schemas
3566 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3567 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3568 GSettings schemas} of GLib are compiled. Compilation is performed by the
3569 @command{glib-compile-schemas} program. It is provided by the package
3570 @code{glib:bin} which is automatically imported by the build system.
3571 The @code{glib} package providing @command{glib-compile-schemas} can be
3572 specified with the @code{#:glib} parameter.
3575 Both phases are executed after the @code{install} phase.
3578 @defvr {Scheme Variable} ocaml-build-system
3579 This variable is exported by @code{(guix build-system ocaml)}. It implements
3580 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3581 of choosing the correct set of commands to run for each package. OCaml
3582 packages can expect many different commands to be run. This build system will
3585 When the package has a @file{setup.ml} file present at the top-level, it will
3586 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3587 @code{ocaml setup.ml -install}. The build system will assume that this file
3588 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3589 care of setting the prefix and enabling tests if they are not disabled. You
3590 can pass configure and build flags with the @code{#:configure-flags} and
3591 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3592 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3593 bypass this system in the build and install phases.
3595 When the package has a @file{configure} file, it is assumed that it is a
3596 hand-made configure script that requires a different argument format than
3597 in the @code{gnu-build-system}. You can add more flags with the
3598 @code{#:configure-flags} key.
3600 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3601 @code{#t}), it will be used and more flags can be passed to the build and
3602 install phases with the @code{#:make-flags} key.
3604 Finally, some packages do not have these files and use a somewhat standard
3605 location for its build system. In that case, the build system will run
3606 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3607 providing the path to the required findlib module. Additional flags can
3608 be passed via the @code{#:build-flags} key. Install is taken care of by
3609 @command{opam-installer}. In this case, the @code{opam} package must
3610 be added to the @code{native-inputs} field of the package definition.
3612 Note that most OCaml packages assume they will be installed in the same
3613 directory as OCaml, which is not what we want in guix. In particular, they
3614 will install @file{.so} files in their module's directory, which is usually
3615 fine because it is in the OCaml compiler directory. In guix though, these
3616 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3617 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3618 @file{.so} libraries should be installed.
3621 @defvr {Scheme Variable} python-build-system
3622 This variable is exported by @code{(guix build-system python)}. It
3623 implements the more or less standard build procedure used by Python
3624 packages, which consists in running @code{python setup.py build} and
3625 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3627 For packages that install stand-alone Python programs under @code{bin/},
3628 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3629 environment variable points to all the Python libraries they depend on.
3631 Which Python package is used to perform the build can be specified with
3632 the @code{#:python} parameter. This is a useful way to force a package
3633 to be built for a specific version of the Python interpreter, which
3634 might be necessary if the package is only compatible with a single
3635 interpreter version.
3637 By default guix calls @code{setup.py} under control of
3638 @code{setuptools}, much like @command{pip} does. Some packages are not
3639 compatible with setuptools (and pip), thus you can disable this by
3640 setting the @code{#:use-setuptools} parameter to @code{#f}.
3643 @defvr {Scheme Variable} perl-build-system
3644 This variable is exported by @code{(guix build-system perl)}. It
3645 implements the standard build procedure for Perl packages, which either
3646 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3647 followed by @code{Build} and @code{Build install}; or in running
3648 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3649 @code{make} and @code{make install}, depending on which of
3650 @code{Build.PL} or @code{Makefile.PL} is present in the package
3651 distribution. Preference is given to the former if both @code{Build.PL}
3652 and @code{Makefile.PL} exist in the package distribution. This
3653 preference can be reversed by specifying @code{#t} for the
3654 @code{#:make-maker?} parameter.
3656 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3657 passes flags specified by the @code{#:make-maker-flags} or
3658 @code{#:module-build-flags} parameter, respectively.
3660 Which Perl package is used can be specified with @code{#:perl}.
3663 @defvr {Scheme Variable} r-build-system
3664 This variable is exported by @code{(guix build-system r)}. It
3665 implements the build procedure used by @uref{http://r-project.org, R}
3666 packages, which essentially is little more than running @code{R CMD
3667 INSTALL --library=/gnu/store/@dots{}} in an environment where
3668 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3669 are run after installation using the R function
3670 @code{tools::testInstalledPackage}.
3673 @defvr {Scheme Variable} texlive-build-system
3674 This variable is exported by @code{(guix build-system texlive)}. It is
3675 used to build TeX packages in batch mode with a specified engine. The
3676 build system sets the @code{TEXINPUTS} variable to find all TeX source
3677 files in the inputs.
3679 By default it runs @code{luatex} on all files ending on @code{ins}. A
3680 different engine and format can be specified with the
3681 @code{#:tex-format} argument. Different build targets can be specified
3682 with the @code{#:build-targets} argument, which expects a list of file
3683 names. The build system adds only @code{texlive-bin} and
3684 @code{texlive-latex-base} (both from @code{(gnu packages tex}) to the
3685 inputs. Both can be overridden with the arguments @code{#:texlive-bin}
3686 and @code{#:texlive-latex-base}, respectively.
3688 The @code{#:tex-directory} parameter tells the build system where to
3689 install the built files under the texmf tree.
3692 @defvr {Scheme Variable} ruby-build-system
3693 This variable is exported by @code{(guix build-system ruby)}. It
3694 implements the RubyGems build procedure used by Ruby packages, which
3695 involves running @code{gem build} followed by @code{gem install}.
3697 The @code{source} field of a package that uses this build system
3698 typically references a gem archive, since this is the format that Ruby
3699 developers use when releasing their software. The build system unpacks
3700 the gem archive, potentially patches the source, runs the test suite,
3701 repackages the gem, and installs it. Additionally, directories and
3702 tarballs may be referenced to allow building unreleased gems from Git or
3703 a traditional source release tarball.
3705 Which Ruby package is used can be specified with the @code{#:ruby}
3706 parameter. A list of additional flags to be passed to the @command{gem}
3707 command can be specified with the @code{#:gem-flags} parameter.
3710 @defvr {Scheme Variable} waf-build-system
3711 This variable is exported by @code{(guix build-system waf)}. It
3712 implements a build procedure around the @code{waf} script. The common
3713 phases---@code{configure}, @code{build}, and @code{install}---are
3714 implemented by passing their names as arguments to the @code{waf}
3717 The @code{waf} script is executed by the Python interpreter. Which
3718 Python package is used to run the script can be specified with the
3719 @code{#:python} parameter.
3722 @defvr {Scheme Variable} haskell-build-system
3723 This variable is exported by @code{(guix build-system haskell)}. It
3724 implements the Cabal build procedure used by Haskell packages, which
3725 involves running @code{runhaskell Setup.hs configure
3726 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3727 Instead of installing the package by running @code{runhaskell Setup.hs
3728 install}, to avoid trying to register libraries in the read-only
3729 compiler store directory, the build system uses @code{runhaskell
3730 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3731 addition, the build system generates the package documentation by
3732 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3733 is passed. Optional Haddock parameters can be passed with the help of
3734 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3735 not found, the build system looks for @code{Setup.lhs} instead.
3737 Which Haskell compiler is used can be specified with the @code{#:haskell}
3738 parameter which defaults to @code{ghc}.
3741 @defvr {Scheme Variable} dub-build-system
3742 This variable is exported by @code{(guix build-system dub)}. It
3743 implements the Dub build procedure used by D packages, which
3744 involves running @code{dub build} and @code{dub run}.
3745 Installation is done by copying the files manually.
3747 Which D compiler is used can be specified with the @code{#:ldc}
3748 parameter which defaults to @code{ldc}.
3751 @defvr {Scheme Variable} emacs-build-system
3752 This variable is exported by @code{(guix build-system emacs)}. It
3753 implements an installation procedure similar to the packaging system
3754 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3756 It first creates the @code{@var{package}-autoloads.el} file, then it
3757 byte compiles all Emacs Lisp files. Differently from the Emacs
3758 packaging system, the Info documentation files are moved to the standard
3759 documentation directory and the @file{dir} file is deleted. Each
3760 package is installed in its own directory under
3761 @file{share/emacs/site-lisp/guix.d}.
3764 @defvr {Scheme Variable} font-build-system
3765 This variable is exported by @code{(guix build-system font)}. It
3766 implements an installation procedure for font packages where upstream
3767 provides pre-compiled TrueType, OpenType, etc. font files that merely
3768 need to be copied into place. It copies font files to standard
3769 locations in the output directory.
3772 Lastly, for packages that do not need anything as sophisticated, a
3773 ``trivial'' build system is provided. It is trivial in the sense that
3774 it provides basically no support: it does not pull any implicit inputs,
3775 and does not have a notion of build phases.
3777 @defvr {Scheme Variable} trivial-build-system
3778 This variable is exported by @code{(guix build-system trivial)}.
3780 This build system requires a @code{#:builder} argument. This argument
3781 must be a Scheme expression that builds the package output(s)---as
3782 with @code{build-expression->derivation} (@pxref{Derivations,
3783 @code{build-expression->derivation}}).
3793 Conceptually, the @dfn{store} is the place where derivations that have
3794 been built successfully are stored---by default, @file{/gnu/store}.
3795 Sub-directories in the store are referred to as @dfn{store items} or
3796 sometimes @dfn{store paths}. The store has an associated database that
3797 contains information such as the store paths referred to by each store
3798 path, and the list of @emph{valid} store items---results of successful
3799 builds. This database resides in @file{@var{localstatedir}/guix/db},
3800 where @var{localstatedir} is the state directory specified @i{via}
3801 @option{--localstatedir} at configure time, usually @file{/var}.
3803 The store is @emph{always} accessed by the daemon on behalf of its clients
3804 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3805 connect to the daemon over a Unix-domain socket, send requests to it,
3806 and read the result---these are remote procedure calls, or RPCs.
3809 Users must @emph{never} modify files under @file{/gnu/store} directly.
3810 This would lead to inconsistencies and break the immutability
3811 assumptions of Guix's functional model (@pxref{Introduction}).
3813 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3814 how to check the integrity of the store and attempt recovery from
3815 accidental modifications.
3818 The @code{(guix store)} module provides procedures to connect to the
3819 daemon, and to perform RPCs. These are described below. By default,
3820 @code{open-connection}, and thus all the @command{guix} commands,
3821 connect to the local daemon or to the URI specified by the
3822 @code{GUIX_DAEMON_SOCKET} environment variable.
3824 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3825 When set, the value of this variable should be a file name or a URI
3826 designating the daemon endpoint. When it is a file name, it denotes a
3827 Unix-domain socket to connect to. In addition to file names, the
3828 supported URI schemes are:
3833 These are for Unix-domain sockets.
3834 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3835 @file{/var/guix/daemon-socket/socket}.
3838 @cindex daemon, remote access
3839 @cindex remote access to the daemon
3840 @cindex daemon, cluster setup
3841 @cindex clusters, daemon setup
3842 These URIs denote connections over TCP/IP, without encryption nor
3843 authentication of the remote host. The URI must specify the host name
3844 and optionally a port number (by default port 44146 is used):
3847 guix://master.guix.example.org:1234
3850 This setup is suitable on local networks, such as clusters, where only
3851 trusted nodes may connect to the build daemon at
3852 @code{master.guix.example.org}.
3854 The @code{--listen} option of @command{guix-daemon} can be used to
3855 instruct it to listen for TCP connections (@pxref{Invoking guix-daemon,
3859 @cindex SSH access to build daemons
3860 These URIs allow you to connect to a remote daemon over
3861 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3862 A typical URL might look like this:
3865 ssh://charlie@@guix.example.org:22
3868 As for @command{guix copy}, the usual OpenSSH client configuration files
3869 are honored (@pxref{Invoking guix copy}).
3872 Additional URI schemes may be supported in the future.
3874 @c XXX: Remove this note when the protocol incurs fewer round trips
3875 @c and when (guix derivations) no longer relies on file system access.
3877 The ability to connect to remote build daemons is considered
3878 experimental as of @value{VERSION}. Please get in touch with us to
3879 share any problems or suggestions you may have (@pxref{Contributing}).
3883 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3884 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3885 @var{reserve-space?} is true, instruct it to reserve a little bit of
3886 extra space on the file system so that the garbage collector can still
3887 operate should the disk become full. Return a server object.
3889 @var{file} defaults to @var{%default-socket-path}, which is the normal
3890 location given the options that were passed to @command{configure}.
3893 @deffn {Scheme Procedure} close-connection @var{server}
3894 Close the connection to @var{server}.
3897 @defvr {Scheme Variable} current-build-output-port
3898 This variable is bound to a SRFI-39 parameter, which refers to the port
3899 where build and error logs sent by the daemon should be written.
3902 Procedures that make RPCs all take a server object as their first
3905 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3906 @cindex invalid store items
3907 Return @code{#t} when @var{path} designates a valid store item and
3908 @code{#f} otherwise (an invalid item may exist on disk but still be
3909 invalid, for instance because it is the result of an aborted or failed
3912 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3913 prefixed by the store directory (@file{/gnu/store}).
3916 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3917 Add @var{text} under file @var{name} in the store, and return its store
3918 path. @var{references} is the list of store paths referred to by the
3919 resulting store path.
3922 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3923 Build @var{derivations} (a list of @code{<derivation>} objects or
3924 derivation paths), and return when the worker is done building them.
3925 Return @code{#t} on success.
3928 Note that the @code{(guix monads)} module provides a monad as well as
3929 monadic versions of the above procedures, with the goal of making it
3930 more convenient to work with code that accesses the store (@pxref{The
3934 @i{This section is currently incomplete.}
3937 @section Derivations
3940 Low-level build actions and the environment in which they are performed
3941 are represented by @dfn{derivations}. A derivation contains the
3942 following pieces of information:
3946 The outputs of the derivation---derivations produce at least one file or
3947 directory in the store, but may produce more.
3950 The inputs of the derivations, which may be other derivations or plain
3951 files in the store (patches, build scripts, etc.)
3954 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3957 The file name of a build script in the store, along with the arguments
3961 A list of environment variables to be defined.
3965 @cindex derivation path
3966 Derivations allow clients of the daemon to communicate build actions to
3967 the store. They exist in two forms: as an in-memory representation,
3968 both on the client- and daemon-side, and as files in the store whose
3969 name end in @code{.drv}---these files are referred to as @dfn{derivation
3970 paths}. Derivations paths can be passed to the @code{build-derivations}
3971 procedure to perform the build actions they prescribe (@pxref{The
3974 The @code{(guix derivations)} module provides a representation of
3975 derivations as Scheme objects, along with procedures to create and
3976 otherwise manipulate derivations. The lowest-level primitive to create
3977 a derivation is the @code{derivation} procedure:
3979 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3980 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3981 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3982 [#:system (%current-system)] [#:references-graphs #f] @
3983 [#:allowed-references #f] [#:disallowed-references #f] @
3984 [#:leaked-env-vars #f] [#:local-build? #f] @
3985 [#:substitutable? #t]
3986 Build a derivation with the given arguments, and return the resulting
3987 @code{<derivation>} object.
3989 When @var{hash} and @var{hash-algo} are given, a
3990 @dfn{fixed-output derivation} is created---i.e., one whose result is
3991 known in advance, such as a file download. If, in addition,
3992 @var{recursive?} is true, then that fixed output may be an executable
3993 file or a directory and @var{hash} must be the hash of an archive
3994 containing this output.
3996 When @var{references-graphs} is true, it must be a list of file
3997 name/store path pairs. In that case, the reference graph of each store
3998 path is exported in the build environment in the corresponding file, in
3999 a simple text format.
4001 When @var{allowed-references} is true, it must be a list of store items
4002 or outputs that the derivation's output may refer to. Likewise,
4003 @var{disallowed-references}, if true, must be a list of things the
4004 outputs may @emph{not} refer to.
4006 When @var{leaked-env-vars} is true, it must be a list of strings
4007 denoting environment variables that are allowed to ``leak'' from the
4008 daemon's environment to the build environment. This is only applicable
4009 to fixed-output derivations---i.e., when @var{hash} is true. The main
4010 use is to allow variables such as @code{http_proxy} to be passed to
4011 derivations that download files.
4013 When @var{local-build?} is true, declare that the derivation is not a
4014 good candidate for offloading and should rather be built locally
4015 (@pxref{Daemon Offload Setup}). This is the case for small derivations
4016 where the costs of data transfers would outweigh the benefits.
4018 When @var{substitutable?} is false, declare that substitutes of the
4019 derivation's output should not be used (@pxref{Substitutes}). This is
4020 useful, for instance, when building packages that capture details of the
4021 host CPU instruction set.
4025 Here's an example with a shell script as its builder, assuming
4026 @var{store} is an open connection to the daemon, and @var{bash} points
4027 to a Bash executable in the store:
4030 (use-modules (guix utils)
4034 (let ((builder ; add the Bash script to the store
4035 (add-text-to-store store "my-builder.sh"
4036 "echo hello world > $out\n" '())))
4037 (derivation store "foo"
4038 bash `("-e" ,builder)
4039 #:inputs `((,bash) (,builder))
4040 #:env-vars '(("HOME" . "/homeless"))))
4041 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
4044 As can be guessed, this primitive is cumbersome to use directly. A
4045 better approach is to write build scripts in Scheme, of course! The
4046 best course of action for that is to write the build code as a
4047 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
4048 information, @pxref{G-Expressions}.
4050 Once upon a time, @code{gexp->derivation} did not exist and constructing
4051 derivations with build code written in Scheme was achieved with
4052 @code{build-expression->derivation}, documented below. This procedure
4053 is now deprecated in favor of the much nicer @code{gexp->derivation}.
4055 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
4056 @var{name} @var{exp} @
4057 [#:system (%current-system)] [#:inputs '()] @
4058 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
4059 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4060 [#:references-graphs #f] [#:allowed-references #f] @
4061 [#:disallowed-references #f] @
4062 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4063 Return a derivation that executes Scheme expression @var{exp} as a
4064 builder for derivation @var{name}. @var{inputs} must be a list of
4065 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
4066 @code{"out"} is assumed. @var{modules} is a list of names of Guile
4067 modules from the current search path to be copied in the store,
4068 compiled, and made available in the load path during the execution of
4069 @var{exp}---e.g., @code{((guix build utils) (guix build
4070 gnu-build-system))}.
4072 @var{exp} is evaluated in an environment where @code{%outputs} is bound
4073 to a list of output/path pairs, and where @code{%build-inputs} is bound
4074 to a list of string/output-path pairs made from @var{inputs}.
4075 Optionally, @var{env-vars} is a list of string pairs specifying the name
4076 and value of environment variables visible to the builder. The builder
4077 terminates by passing the result of @var{exp} to @code{exit}; thus, when
4078 @var{exp} returns @code{#f}, the build is considered to have failed.
4080 @var{exp} is built using @var{guile-for-build} (a derivation). When
4081 @var{guile-for-build} is omitted or is @code{#f}, the value of the
4082 @code{%guile-for-build} fluid is used instead.
4084 See the @code{derivation} procedure for the meaning of
4085 @var{references-graphs}, @var{allowed-references},
4086 @var{disallowed-references}, @var{local-build?}, and
4087 @var{substitutable?}.
4091 Here's an example of a single-output derivation that creates a directory
4092 containing one file:
4095 (let ((builder '(let ((out (assoc-ref %outputs "out")))
4096 (mkdir out) ; create /gnu/store/@dots{}-goo
4097 (call-with-output-file (string-append out "/test")
4099 (display '(hello guix) p))))))
4100 (build-expression->derivation store "goo" builder))
4102 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
4106 @node The Store Monad
4107 @section The Store Monad
4111 The procedures that operate on the store described in the previous
4112 sections all take an open connection to the build daemon as their first
4113 argument. Although the underlying model is functional, they either have
4114 side effects or depend on the current state of the store.
4116 The former is inconvenient: the connection to the build daemon has to be
4117 carried around in all those functions, making it impossible to compose
4118 functions that do not take that parameter with functions that do. The
4119 latter can be problematic: since store operations have side effects
4120 and/or depend on external state, they have to be properly sequenced.
4122 @cindex monadic values
4123 @cindex monadic functions
4124 This is where the @code{(guix monads)} module comes in. This module
4125 provides a framework for working with @dfn{monads}, and a particularly
4126 useful monad for our uses, the @dfn{store monad}. Monads are a
4127 construct that allows two things: associating ``context'' with values
4128 (in our case, the context is the store), and building sequences of
4129 computations (here computations include accesses to the store). Values
4130 in a monad---values that carry this additional context---are called
4131 @dfn{monadic values}; procedures that return such values are called
4132 @dfn{monadic procedures}.
4134 Consider this ``normal'' procedure:
4137 (define (sh-symlink store)
4138 ;; Return a derivation that symlinks the 'bash' executable.
4139 (let* ((drv (package-derivation store bash))
4140 (out (derivation->output-path drv))
4141 (sh (string-append out "/bin/bash")))
4142 (build-expression->derivation store "sh"
4143 `(symlink ,sh %output))))
4146 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
4147 as a monadic function:
4150 (define (sh-symlink)
4151 ;; Same, but return a monadic value.
4152 (mlet %store-monad ((drv (package->derivation bash)))
4153 (gexp->derivation "sh"
4154 #~(symlink (string-append #$drv "/bin/bash")
4158 There are several things to note in the second version: the @code{store}
4159 parameter is now implicit and is ``threaded'' in the calls to the
4160 @code{package->derivation} and @code{gexp->derivation} monadic
4161 procedures, and the monadic value returned by @code{package->derivation}
4162 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4164 As it turns out, the call to @code{package->derivation} can even be
4165 omitted since it will take place implicitly, as we will see later
4166 (@pxref{G-Expressions}):
4169 (define (sh-symlink)
4170 (gexp->derivation "sh"
4171 #~(symlink (string-append #$bash "/bin/bash")
4176 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4177 @c for the funny quote.
4178 Calling the monadic @code{sh-symlink} has no effect. As someone once
4179 said, ``you exit a monad like you exit a building on fire: by running''.
4180 So, to exit the monad and get the desired effect, one must use
4181 @code{run-with-store}:
4184 (run-with-store (open-connection) (sh-symlink))
4185 @result{} /gnu/store/...-sh-symlink
4188 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4189 new ``meta-commands'' to make it easier to deal with monadic procedures:
4190 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4191 to ``run'' a single monadic value through the store:
4194 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4195 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4198 The latter enters a recursive REPL, where all the return values are
4199 automatically run through the store:
4202 scheme@@(guile-user)> ,enter-store-monad
4203 store-monad@@(guile-user) [1]> (package->derivation hello)
4204 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4205 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4206 $3 = "/gnu/store/@dots{}-foo"
4207 store-monad@@(guile-user) [1]> ,q
4208 scheme@@(guile-user)>
4212 Note that non-monadic values cannot be returned in the
4213 @code{store-monad} REPL.
4215 The main syntactic forms to deal with monads in general are provided by
4216 the @code{(guix monads)} module and are described below.
4218 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4219 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4223 @deffn {Scheme Syntax} return @var{val}
4224 Return a monadic value that encapsulates @var{val}.
4227 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4228 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4229 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4230 referred to as ``bind'', but that name denotes an unrelated procedure in
4231 Guile. Thus we use this somewhat cryptic symbol inherited from the
4232 Haskell language.}. There can be one @var{mproc} or several of them, as
4237 (with-monad %state-monad
4239 (lambda (x) (return (+ 1 x)))
4240 (lambda (x) (return (* 2 x)))))
4244 @result{} some-state
4248 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4250 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4252 Bind the variables @var{var} to the monadic values @var{mval} in
4253 @var{body}, which is a sequence of expressions. As with the bind
4254 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4255 value ``contained'' in @var{mval} and making @var{var} refer to that
4256 raw, non-monadic value within the scope of the @var{body}. The form
4257 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4258 @var{val}, as per @code{let}. The binding operations occur in sequence
4259 from left to right. The last expression of @var{body} must be a monadic
4260 expression, and its result will become the result of the @code{mlet} or
4261 @code{mlet*} when run in the @var{monad}.
4263 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4264 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4267 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4268 Bind @var{mexp} and the following monadic expressions in sequence,
4269 returning the result of the last expression. Every expression in the
4270 sequence must be a monadic expression.
4272 This is akin to @code{mlet}, except that the return values of the
4273 monadic expressions are ignored. In that sense, it is analogous to
4274 @code{begin}, but applied to monadic expressions.
4277 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4278 When @var{condition} is true, evaluate the sequence of monadic
4279 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4280 @var{condition} is false, return @code{*unspecified*} in the current
4281 monad. Every expression in the sequence must be a monadic expression.
4284 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4285 When @var{condition} is false, evaluate the sequence of monadic
4286 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4287 @var{condition} is true, return @code{*unspecified*} in the current
4288 monad. Every expression in the sequence must be a monadic expression.
4292 The @code{(guix monads)} module provides the @dfn{state monad}, which
4293 allows an additional value---the state---to be @emph{threaded} through
4294 monadic procedure calls.
4296 @defvr {Scheme Variable} %state-monad
4297 The state monad. Procedures in the state monad can access and change
4298 the state that is threaded.
4300 Consider the example below. The @code{square} procedure returns a value
4301 in the state monad. It returns the square of its argument, but also
4302 increments the current state value:
4306 (mlet %state-monad ((count (current-state)))
4307 (mbegin %state-monad
4308 (set-current-state (+ 1 count))
4311 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4316 When ``run'' through @var{%state-monad}, we obtain that additional state
4317 value, which is the number of @code{square} calls.
4320 @deffn {Monadic Procedure} current-state
4321 Return the current state as a monadic value.
4324 @deffn {Monadic Procedure} set-current-state @var{value}
4325 Set the current state to @var{value} and return the previous state as a
4329 @deffn {Monadic Procedure} state-push @var{value}
4330 Push @var{value} to the current state, which is assumed to be a list,
4331 and return the previous state as a monadic value.
4334 @deffn {Monadic Procedure} state-pop
4335 Pop a value from the current state and return it as a monadic value.
4336 The state is assumed to be a list.
4339 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4340 Run monadic value @var{mval} starting with @var{state} as the initial
4341 state. Return two values: the resulting value, and the resulting state.
4344 The main interface to the store monad, provided by the @code{(guix
4345 store)} module, is as follows.
4347 @defvr {Scheme Variable} %store-monad
4348 The store monad---an alias for @var{%state-monad}.
4350 Values in the store monad encapsulate accesses to the store. When its
4351 effect is needed, a value of the store monad must be ``evaluated'' by
4352 passing it to the @code{run-with-store} procedure (see below.)
4355 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4356 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4357 open store connection.
4360 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4361 Return as a monadic value the absolute file name in the store of the file
4362 containing @var{text}, a string. @var{references} is a list of store items that the
4363 resulting text file refers to; it defaults to the empty list.
4366 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4367 [#:recursive? #t] [#:select? (const #t)]
4368 Return the name of @var{file} once interned in the store. Use
4369 @var{name} as its store name, or the basename of @var{file} if
4370 @var{name} is omitted.
4372 When @var{recursive?} is true, the contents of @var{file} are added
4373 recursively; if @var{file} designates a flat file and @var{recursive?}
4374 is true, its contents are added, and its permission bits are kept.
4376 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4377 @var{stat})} for each directory entry, where @var{file} is the entry's
4378 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4379 entries for which @var{select?} does not return true.
4381 The example below adds a file to the store, under two different names:
4384 (run-with-store (open-connection)
4385 (mlet %store-monad ((a (interned-file "README"))
4386 (b (interned-file "README" "LEGU-MIN")))
4387 (return (list a b))))
4389 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4394 The @code{(guix packages)} module exports the following package-related
4397 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4398 [#:system (%current-system)] [#:target #f] @
4401 value in the absolute file name of @var{file} within the @var{output}
4402 directory of @var{package}. When @var{file} is omitted, return the name
4403 of the @var{output} directory of @var{package}. When @var{target} is
4404 true, use it as a cross-compilation target triplet.
4407 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4408 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4409 @var{target} [@var{system}]
4410 Monadic version of @code{package-derivation} and
4411 @code{package-cross-derivation} (@pxref{Defining Packages}).
4416 @section G-Expressions
4418 @cindex G-expression
4419 @cindex build code quoting
4420 So we have ``derivations'', which represent a sequence of build actions
4421 to be performed to produce an item in the store (@pxref{Derivations}).
4422 These build actions are performed when asking the daemon to actually
4423 build the derivations; they are run by the daemon in a container
4424 (@pxref{Invoking guix-daemon}).
4426 @cindex strata of code
4427 It should come as no surprise that we like to write these build actions
4428 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4429 code@footnote{The term @dfn{stratum} in this context was coined by
4430 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4431 Kiselyov, who has written insightful
4432 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4433 on this topic}, refers to this kind of code generation as
4434 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4435 to the daemon, etc.---and the ``build code''---code that actually
4436 performs build actions, such as making directories, invoking
4437 @command{make}, etc.
4439 To describe a derivation and its build actions, one typically needs to
4440 embed build code inside host code. It boils down to manipulating build
4441 code as data, and the homoiconicity of Scheme---code has a direct
4442 representation as data---comes in handy for that. But we need more than
4443 the normal @code{quasiquote} mechanism in Scheme to construct build
4446 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4447 S-expressions adapted to build expressions. G-expressions, or
4448 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4449 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4450 @code{#$}, and @code{#$@@}), which are comparable to
4451 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4452 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4453 GNU Guile Reference Manual}). However, there are major differences:
4457 Gexps are meant to be written to a file and run or manipulated by other
4461 When a high-level object such as a package or derivation is unquoted
4462 inside a gexp, the result is as if its output file name had been
4466 Gexps carry information about the packages or derivations they refer to,
4467 and these dependencies are automatically added as inputs to the build
4468 processes that use them.
4471 @cindex lowering, of high-level objects in gexps
4472 This mechanism is not limited to package and derivation
4473 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4474 derivations or files in the store can be defined,
4475 such that these objects can also be inserted
4476 into gexps. For example, a useful type of high-level objects that can be
4477 inserted in a gexp is ``file-like objects'', which make it easy to
4478 add files to the store and to refer to them in
4479 derivations and such (see @code{local-file} and @code{plain-file}
4482 To illustrate the idea, here is an example of a gexp:
4489 (symlink (string-append #$coreutils "/bin/ls")
4493 This gexp can be passed to @code{gexp->derivation}; we obtain a
4494 derivation that builds a directory containing exactly one symlink to
4495 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4498 (gexp->derivation "the-thing" build-exp)
4501 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4502 substituted to the reference to the @var{coreutils} package in the
4503 actual build code, and @var{coreutils} is automatically made an input to
4504 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4505 output)}) is replaced by a string containing the directory name of the
4506 output of the derivation.
4508 @cindex cross compilation
4509 In a cross-compilation context, it is useful to distinguish between
4510 references to the @emph{native} build of a package---that can run on the
4511 host---versus references to cross builds of a package. To that end, the
4512 @code{#+} plays the same role as @code{#$}, but is a reference to a
4513 native package build:
4516 (gexp->derivation "vi"
4519 (system* (string-append #+coreutils "/bin/ln")
4521 (string-append #$emacs "/bin/emacs")
4522 (string-append #$output "/bin/vi")))
4523 #:target "mips64el-linux-gnu")
4527 In the example above, the native build of @var{coreutils} is used, so
4528 that @command{ln} can actually run on the host; but then the
4529 cross-compiled build of @var{emacs} is referenced.
4531 @cindex imported modules, for gexps
4532 @findex with-imported-modules
4533 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4534 able to use certain Guile modules from the ``host environment'' in the
4535 gexp, so those modules should be imported in the ``build environment''.
4536 The @code{with-imported-modules} form allows you to express that:
4539 (let ((build (with-imported-modules '((guix build utils))
4541 (use-modules (guix build utils))
4542 (mkdir-p (string-append #$output "/bin"))))))
4543 (gexp->derivation "empty-dir"
4546 (display "success!\n")
4551 In this example, the @code{(guix build utils)} module is automatically
4552 pulled into the isolated build environment of our gexp, such that
4553 @code{(use-modules (guix build utils))} works as expected.
4555 @cindex module closure
4556 @findex source-module-closure
4557 Usually you want the @emph{closure} of the module to be imported---i.e.,
4558 the module itself and all the modules it depends on---rather than just
4559 the module; failing to do that, attempts to use the module will fail
4560 because of missing dependent modules. The @code{source-module-closure}
4561 procedure computes the closure of a module by looking at its source file
4562 headers, which comes in handy in this case:
4565 (use-modules (guix modules)) ;for 'source-module-closure'
4567 (with-imported-modules (source-module-closure
4568 '((guix build utils)
4570 (gexp->derivation "something-with-vms"
4572 (use-modules (guix build utils)
4577 The syntactic form to construct gexps is summarized below.
4579 @deffn {Scheme Syntax} #~@var{exp}
4580 @deffnx {Scheme Syntax} (gexp @var{exp})
4581 Return a G-expression containing @var{exp}. @var{exp} may contain one
4582 or more of the following forms:
4586 @itemx (ungexp @var{obj})
4587 Introduce a reference to @var{obj}. @var{obj} may have one of the
4588 supported types, for example a package or a
4589 derivation, in which case the @code{ungexp} form is replaced by its
4590 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4592 If @var{obj} is a list, it is traversed and references to supported
4593 objects are substituted similarly.
4595 If @var{obj} is another gexp, its contents are inserted and its
4596 dependencies are added to those of the containing gexp.
4598 If @var{obj} is another kind of object, it is inserted as is.
4600 @item #$@var{obj}:@var{output}
4601 @itemx (ungexp @var{obj} @var{output})
4602 This is like the form above, but referring explicitly to the
4603 @var{output} of @var{obj}---this is useful when @var{obj} produces
4604 multiple outputs (@pxref{Packages with Multiple Outputs}).
4607 @itemx #+@var{obj}:output
4608 @itemx (ungexp-native @var{obj})
4609 @itemx (ungexp-native @var{obj} @var{output})
4610 Same as @code{ungexp}, but produces a reference to the @emph{native}
4611 build of @var{obj} when used in a cross compilation context.
4613 @item #$output[:@var{output}]
4614 @itemx (ungexp output [@var{output}])
4615 Insert a reference to derivation output @var{output}, or to the main
4616 output when @var{output} is omitted.
4618 This only makes sense for gexps passed to @code{gexp->derivation}.
4621 @itemx (ungexp-splicing @var{lst})
4622 Like the above, but splices the contents of @var{lst} inside the
4626 @itemx (ungexp-native-splicing @var{lst})
4627 Like the above, but refers to native builds of the objects listed in
4632 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4633 of the @code{gexp?} type (see below.)
4636 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4637 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4638 in their execution environment.
4640 Each item in @var{modules} can be the name of a module, such as
4641 @code{(guix build utils)}, or it can be a module name, followed by an
4642 arrow, followed by a file-like object:
4645 `((guix build utils)
4647 ((guix config) => ,(scheme-file "config.scm"
4648 #~(define-module @dots{}))))
4652 In the example above, the first two modules are taken from the search
4653 path, and the last one is created from the given file-like object.
4655 This form has @emph{lexical} scope: it has an effect on the gexps
4656 directly defined in @var{body}@dots{}, but not on those defined, say, in
4657 procedures called from @var{body}@dots{}.
4660 @deffn {Scheme Procedure} gexp? @var{obj}
4661 Return @code{#t} if @var{obj} is a G-expression.
4664 G-expressions are meant to be written to disk, either as code building
4665 some derivation, or as plain files in the store. The monadic procedures
4666 below allow you to do that (@pxref{The Store Monad}, for more
4667 information about monads.)
4669 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4670 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4671 [#:hash #f] [#:hash-algo #f] @
4672 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4673 [#:module-path @var{%load-path}] @
4674 [#:references-graphs #f] [#:allowed-references #f] @
4675 [#:disallowed-references #f] @
4676 [#:leaked-env-vars #f] @
4677 [#:script-name (string-append @var{name} "-builder")] @
4678 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4679 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4680 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4681 stored in a file called @var{script-name}. When @var{target} is true,
4682 it is used as the cross-compilation target triplet for packages referred
4685 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4687 make @var{modules} available in the evaluation context of @var{exp};
4688 @var{modules} is a list of names of Guile modules searched in
4689 @var{module-path} to be copied in the store, compiled, and made available in
4690 the load path during the execution of @var{exp}---e.g., @code{((guix
4691 build utils) (guix build gnu-build-system))}.
4693 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4696 When @var{references-graphs} is true, it must be a list of tuples of one of the
4700 (@var{file-name} @var{package})
4701 (@var{file-name} @var{package} @var{output})
4702 (@var{file-name} @var{derivation})
4703 (@var{file-name} @var{derivation} @var{output})
4704 (@var{file-name} @var{store-item})
4707 The right-hand-side of each element of @var{references-graphs} is automatically made
4708 an input of the build process of @var{exp}. In the build environment, each
4709 @var{file-name} contains the reference graph of the corresponding item, in a simple
4712 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4713 In the latter case, the list denotes store items that the result is allowed to
4714 refer to. Any reference to another store item will lead to a build error.
4715 Similarly for @var{disallowed-references}, which can list items that must not be
4716 referenced by the outputs.
4718 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4721 @cindex file-like objects
4722 The @code{local-file}, @code{plain-file}, @code{computed-file},
4723 @code{program-file}, and @code{scheme-file} procedures below return
4724 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4725 these objects lead to a file in the store. Consider this G-expression:
4728 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4729 #$(local-file "/tmp/my-nscd.conf"))
4732 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4733 to the store. Once expanded, for instance @i{via}
4734 @code{gexp->derivation}, the G-expression refers to that copy under
4735 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4736 does not have any effect on what the G-expression does.
4737 @code{plain-file} can be used similarly; it differs in that the file
4738 content is directly passed as a string.
4740 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4741 [#:recursive? #f] [#:select? (const #t)]
4742 Return an object representing local file @var{file} to add to the store; this
4743 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4744 up relative to the source file where this form appears. @var{file} will be added to
4745 the store under @var{name}--by default the base name of @var{file}.
4747 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4748 designates a flat file and @var{recursive?} is true, its contents are added, and its
4749 permission bits are kept.
4751 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4752 @var{stat})} for each directory entry, where @var{file} is the entry's
4753 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4754 entries for which @var{select?} does not return true.
4756 This is the declarative counterpart of the @code{interned-file} monadic
4757 procedure (@pxref{The Store Monad, @code{interned-file}}).
4760 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4761 Return an object representing a text file called @var{name} with the given
4762 @var{content} (a string) to be added to the store.
4764 This is the declarative counterpart of @code{text-file}.
4767 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4768 [#:options '(#:local-build? #t)]
4769 Return an object representing the store item @var{name}, a file or
4770 directory computed by @var{gexp}. @var{options}
4771 is a list of additional arguments to pass to @code{gexp->derivation}.
4773 This is the declarative counterpart of @code{gexp->derivation}.
4776 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4777 Return an executable script @var{name} that runs @var{exp} using
4778 @var{guile}, with @var{exp}'s imported modules in its search path.
4780 The example below builds a script that simply invokes the @command{ls}
4784 (use-modules (guix gexp) (gnu packages base))
4786 (gexp->script "list-files"
4787 #~(execl #$(file-append coreutils "/bin/ls")
4791 When ``running'' it through the store (@pxref{The Store Monad,
4792 @code{run-with-store}}), we obtain a derivation that produces an
4793 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4796 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4798 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4802 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4804 Return an object representing the executable store item @var{name} that
4805 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4808 This is the declarative counterpart of @code{gexp->script}.
4811 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4812 [#:set-load-path? #t]
4813 Return a derivation that builds a file @var{name} containing @var{exp}.
4814 When @var{set-load-path?} is true, emit code in the resulting file to
4815 set @code{%load-path} and @code{%load-compiled-path} to honor
4816 @var{exp}'s imported modules.
4818 The resulting file holds references to all the dependencies of @var{exp}
4819 or a subset thereof.
4822 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4823 Return an object representing the Scheme file @var{name} that contains
4826 This is the declarative counterpart of @code{gexp->file}.
4829 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4830 Return as a monadic value a derivation that builds a text file
4831 containing all of @var{text}. @var{text} may list, in addition to
4832 strings, objects of any type that can be used in a gexp: packages,
4833 derivations, local file objects, etc. The resulting store file holds
4834 references to all these.
4836 This variant should be preferred over @code{text-file} anytime the file
4837 to create will reference items from the store. This is typically the
4838 case when building a configuration file that embeds store file names,
4842 (define (profile.sh)
4843 ;; Return the name of a shell script in the store that
4844 ;; initializes the 'PATH' environment variable.
4845 (text-file* "profile.sh"
4846 "export PATH=" coreutils "/bin:"
4847 grep "/bin:" sed "/bin\n"))
4850 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4851 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4852 preventing them from being garbage-collected during its lifetime.
4855 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4856 Return an object representing store file @var{name} containing
4857 @var{text}. @var{text} is a sequence of strings and file-like objects,
4861 (mixed-text-file "profile"
4862 "export PATH=" coreutils "/bin:" grep "/bin")
4865 This is the declarative counterpart of @code{text-file*}.
4868 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4869 Return a file-like object that expands to the concatenation of @var{obj}
4870 and @var{suffix}, where @var{obj} is a lowerable object and each
4871 @var{suffix} is a string.
4873 As an example, consider this gexp:
4876 (gexp->script "run-uname"
4877 #~(system* #$(file-append coreutils
4881 The same effect could be achieved with:
4884 (gexp->script "run-uname"
4885 #~(system* (string-append #$coreutils
4889 There is one difference though: in the @code{file-append} case, the
4890 resulting script contains the absolute file name as a string, whereas in
4891 the second case, the resulting script contains a @code{(string-append
4892 @dots{})} expression to construct the file name @emph{at run time}.
4896 Of course, in addition to gexps embedded in ``host'' code, there are
4897 also modules containing build tools. To make it clear that they are
4898 meant to be used in the build stratum, these modules are kept in the
4899 @code{(guix build @dots{})} name space.
4901 @cindex lowering, of high-level objects in gexps
4902 Internally, high-level objects are @dfn{lowered}, using their compiler,
4903 to either derivations or store items. For instance, lowering a package
4904 yields a derivation, and lowering a @code{plain-file} yields a store
4905 item. This is achieved using the @code{lower-object} monadic procedure.
4907 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4909 Return as a value in @var{%store-monad} the derivation or store item
4910 corresponding to @var{obj} for @var{system}, cross-compiling for
4911 @var{target} if @var{target} is true. @var{obj} must be an object that
4912 has an associated gexp compiler, such as a @code{<package>}.
4916 @c *********************************************************************
4920 This section describes Guix command-line utilities. Some of them are
4921 primarily targeted at developers and users who write new package
4922 definitions, while others are more generally useful. They complement
4923 the Scheme programming interface of Guix in a convenient way.
4926 * Invoking guix build:: Building packages from the command line.
4927 * Invoking guix edit:: Editing package definitions.
4928 * Invoking guix download:: Downloading a file and printing its hash.
4929 * Invoking guix hash:: Computing the cryptographic hash of a file.
4930 * Invoking guix import:: Importing package definitions.
4931 * Invoking guix refresh:: Updating package definitions.
4932 * Invoking guix lint:: Finding errors in package definitions.
4933 * Invoking guix size:: Profiling disk usage.
4934 * Invoking guix graph:: Visualizing the graph of packages.
4935 * Invoking guix environment:: Setting up development environments.
4936 * Invoking guix publish:: Sharing substitutes.
4937 * Invoking guix challenge:: Challenging substitute servers.
4938 * Invoking guix copy:: Copying to and from a remote store.
4939 * Invoking guix container:: Process isolation.
4940 * Invoking guix weather:: Assessing substitute availability.
4943 @node Invoking guix build
4944 @section Invoking @command{guix build}
4946 @cindex package building
4947 @cindex @command{guix build}
4948 The @command{guix build} command builds packages or derivations and
4949 their dependencies, and prints the resulting store paths. Note that it
4950 does not modify the user's profile---this is the job of the
4951 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4952 it is mainly useful for distribution developers.
4954 The general syntax is:
4957 guix build @var{options} @var{package-or-derivation}@dots{}
4960 As an example, the following command builds the latest versions of Emacs
4961 and of Guile, displays their build logs, and finally displays the
4962 resulting directories:
4965 guix build emacs guile
4968 Similarly, the following command builds all the available packages:
4971 guix build --quiet --keep-going \
4972 `guix package -A | cut -f1,2 --output-delimiter=@@`
4975 @var{package-or-derivation} may be either the name of a package found in
4976 the software distribution such as @code{coreutils} or
4977 @code{coreutils@@8.20}, or a derivation such as
4978 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4979 package with the corresponding name (and optionally version) is searched
4980 for among the GNU distribution modules (@pxref{Package Modules}).
4982 Alternatively, the @code{--expression} option may be used to specify a
4983 Scheme expression that evaluates to a package; this is useful when
4984 disambiguating among several same-named packages or package variants is
4987 There may be zero or more @var{options}. The available options are
4988 described in the subsections below.
4991 * Common Build Options:: Build options for most commands.
4992 * Package Transformation Options:: Creating variants of packages.
4993 * Additional Build Options:: Options specific to 'guix build'.
4994 * Debugging Build Failures:: Real life packaging experience.
4997 @node Common Build Options
4998 @subsection Common Build Options
5000 A number of options that control the build process are common to
5001 @command{guix build} and other commands that can spawn builds, such as
5002 @command{guix package} or @command{guix archive}. These are the
5007 @item --load-path=@var{directory}
5008 @itemx -L @var{directory}
5009 Add @var{directory} to the front of the package module search path
5010 (@pxref{Package Modules}).
5012 This allows users to define their own packages and make them visible to
5013 the command-line tools.
5017 Keep the build tree of failed builds. Thus, if a build fails, its build
5018 tree is kept under @file{/tmp}, in a directory whose name is shown at
5019 the end of the build log. This is useful when debugging build issues.
5020 @xref{Debugging Build Failures}, for tips and tricks on how to debug
5025 Keep going when some of the derivations fail to build; return only once
5026 all the builds have either completed or failed.
5028 The default behavior is to stop as soon as one of the specified
5029 derivations has failed.
5033 Do not build the derivations.
5036 When substituting a pre-built binary fails, fall back to building
5039 @item --substitute-urls=@var{urls}
5040 @anchor{client-substitute-urls}
5041 Consider @var{urls} the whitespace-separated list of substitute source
5042 URLs, overriding the default list of URLs of @command{guix-daemon}
5043 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
5045 This means that substitutes may be downloaded from @var{urls}, provided
5046 they are signed by a key authorized by the system administrator
5047 (@pxref{Substitutes}).
5049 When @var{urls} is the empty string, substitutes are effectively
5052 @item --no-substitutes
5053 Do not use substitutes for build products. That is, always build things
5054 locally instead of allowing downloads of pre-built binaries
5055 (@pxref{Substitutes}).
5058 Do not ``graft'' packages. In practice, this means that package updates
5059 available as grafts are not applied. @xref{Security Updates}, for more
5060 information on grafts.
5062 @item --rounds=@var{n}
5063 Build each derivation @var{n} times in a row, and raise an error if
5064 consecutive build results are not bit-for-bit identical.
5066 This is a useful way to detect non-deterministic builds processes.
5067 Non-deterministic build processes are a problem because they make it
5068 practically impossible for users to @emph{verify} whether third-party
5069 binaries are genuine. @xref{Invoking guix challenge}, for more.
5071 Note that, currently, the differing build results are not kept around,
5072 so you will have to manually investigate in case of an error---e.g., by
5073 stashing one of the build results with @code{guix archive --export}
5074 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
5077 @item --no-build-hook
5078 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
5079 (@pxref{Daemon Offload Setup}). That is, always build things locally
5080 instead of offloading builds to remote machines.
5082 @item --max-silent-time=@var{seconds}
5083 When the build or substitution process remains silent for more than
5084 @var{seconds}, terminate it and report a build failure.
5086 By default, the daemon's setting is honored (@pxref{Invoking
5087 guix-daemon, @code{--max-silent-time}}).
5089 @item --timeout=@var{seconds}
5090 Likewise, when the build or substitution process lasts for more than
5091 @var{seconds}, terminate it and report a build failure.
5093 By default, the daemon's setting is honored (@pxref{Invoking
5094 guix-daemon, @code{--timeout}}).
5096 @item --verbosity=@var{level}
5097 Use the given verbosity level. @var{level} must be an integer between 0
5098 and 5; higher means more verbose output. Setting a level of 4 or more
5099 may be helpful when debugging setup issues with the build daemon.
5101 @item --cores=@var{n}
5103 Allow the use of up to @var{n} CPU cores for the build. The special
5104 value @code{0} means to use as many CPU cores as available.
5106 @item --max-jobs=@var{n}
5108 Allow at most @var{n} build jobs in parallel. @xref{Invoking
5109 guix-daemon, @code{--max-jobs}}, for details about this option and the
5110 equivalent @command{guix-daemon} option.
5114 Behind the scenes, @command{guix build} is essentially an interface to
5115 the @code{package-derivation} procedure of the @code{(guix packages)}
5116 module, and to the @code{build-derivations} procedure of the @code{(guix
5117 derivations)} module.
5119 In addition to options explicitly passed on the command line,
5120 @command{guix build} and other @command{guix} commands that support
5121 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
5123 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
5124 Users can define this variable to a list of command line options that
5125 will automatically be used by @command{guix build} and other
5126 @command{guix} commands that can perform builds, as in the example
5130 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
5133 These options are parsed independently, and the result is appended to
5134 the parsed command-line options.
5138 @node Package Transformation Options
5139 @subsection Package Transformation Options
5141 @cindex package variants
5142 Another set of command-line options supported by @command{guix build}
5143 and also @command{guix package} are @dfn{package transformation
5144 options}. These are options that make it possible to define @dfn{package
5145 variants}---for instance, packages built from different source code.
5146 This is a convenient way to create customized packages on the fly
5147 without having to type in the definitions of package variants
5148 (@pxref{Defining Packages}).
5152 @item --with-source=@var{source}
5153 Use @var{source} as the source of the corresponding package.
5154 @var{source} must be a file name or a URL, as for @command{guix
5155 download} (@pxref{Invoking guix download}).
5157 The ``corresponding package'' is taken to be the one specified on the
5158 command line the name of which matches the base of @var{source}---e.g.,
5159 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5160 package is @code{guile}. Likewise, the version string is inferred from
5161 @var{source}; in the previous example, it is @code{2.0.10}.
5163 This option allows users to try out versions of packages other than the
5164 one provided by the distribution. The example below downloads
5165 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5166 the @code{ed} package:
5169 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5172 As a developer, @code{--with-source} makes it easy to test release
5176 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5179 @dots{} or to build from a checkout in a pristine environment:
5182 $ git clone git://git.sv.gnu.org/guix.git
5183 $ guix build guix --with-source=./guix
5186 @item --with-input=@var{package}=@var{replacement}
5187 Replace dependency on @var{package} by a dependency on
5188 @var{replacement}. @var{package} must be a package name, and
5189 @var{replacement} must be a package specification such as @code{guile}
5190 or @code{guile@@1.8}.
5192 For instance, the following command builds Guix, but replaces its
5193 dependency on the current stable version of Guile with a dependency on
5194 the legacy version of Guile, @code{guile@@2.0}:
5197 guix build --with-input=guile=guile@@2.0 guix
5200 This is a recursive, deep replacement. So in this example, both
5201 @code{guix} and its dependency @code{guile-json} (which also depends on
5202 @code{guile}) get rebuilt against @code{guile@@2.0}.
5204 This is implemented using the @code{package-input-rewriting} Scheme
5205 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5207 @item --with-graft=@var{package}=@var{replacement}
5208 This is similar to @code{--with-input} but with an important difference:
5209 instead of rebuilding the whole dependency chain, @var{replacement} is
5210 built and then @dfn{grafted} onto the binaries that were initially
5211 referring to @var{package}. @xref{Security Updates}, for more
5212 information on grafts.
5214 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5215 and all its dependencies, replacing references to the version of GnuTLS
5216 they currently refer to:
5219 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5222 This has the advantage of being much faster than rebuilding everything.
5223 But there is a caveat: it works if and only if @var{package} and
5224 @var{replacement} are strictly compatible---for example, if they provide
5225 a library, the application binary interface (ABI) of those libraries
5226 must be compatible. If @var{replacement} is somehow incompatible with
5227 @var{package}, then the resulting package may be unusable. Use with
5232 @node Additional Build Options
5233 @subsection Additional Build Options
5235 The command-line options presented below are specific to @command{guix
5242 Build quietly, without displaying the build log. Upon completion, the
5243 build log is kept in @file{/var} (or similar) and can always be
5244 retrieved using the @option{--log-file} option.
5246 @item --file=@var{file}
5247 @itemx -f @var{file}
5249 Build the package or derivation that the code within @var{file}
5252 As an example, @var{file} might contain a package definition like this
5253 (@pxref{Defining Packages}):
5256 @verbatiminclude package-hello.scm
5259 @item --expression=@var{expr}
5260 @itemx -e @var{expr}
5261 Build the package or derivation @var{expr} evaluates to.
5263 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5264 guile-1.8)}, which unambiguously designates this specific variant of
5265 version 1.8 of Guile.
5267 Alternatively, @var{expr} may be a G-expression, in which case it is used
5268 as a build program passed to @code{gexp->derivation}
5269 (@pxref{G-Expressions}).
5271 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5272 (@pxref{The Store Monad}). The procedure must return a derivation as a
5273 monadic value, which is then passed through @code{run-with-store}.
5277 Build the source derivations of the packages, rather than the packages
5280 For instance, @code{guix build -S gcc} returns something like
5281 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5284 The returned source tarball is the result of applying any patches and
5285 code snippets specified in the package @code{origin} (@pxref{Defining
5289 Fetch and return the source of @var{package-or-derivation} and all their
5290 dependencies, recursively. This is a handy way to obtain a local copy
5291 of all the source code needed to build @var{packages}, allowing you to
5292 eventually build them even without network access. It is an extension
5293 of the @code{--source} option and can accept one of the following
5294 optional argument values:
5298 This value causes the @code{--sources} option to behave in the same way
5299 as the @code{--source} option.
5302 Build the source derivations of all packages, including any source that
5303 might be listed as @code{inputs}. This is the default value.
5306 $ guix build --sources tzdata
5307 The following derivations will be built:
5308 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5309 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5313 Build the source derivations of all packages, as well of all transitive
5314 inputs to the packages. This can be used e.g. to
5315 prefetch package source for later offline building.
5318 $ guix build --sources=transitive tzdata
5319 The following derivations will be built:
5320 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5321 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5322 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5323 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5324 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5325 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5331 @item --system=@var{system}
5332 @itemx -s @var{system}
5333 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5334 the system type of the build host.
5336 An example use of this is on Linux-based systems, which can emulate
5337 different personalities. For instance, passing
5338 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5339 to build packages in a complete 32-bit environment.
5341 @item --target=@var{triplet}
5342 @cindex cross-compilation
5343 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5344 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5345 configuration triplets,, autoconf, Autoconf}).
5347 @anchor{build-check}
5349 @cindex determinism, checking
5350 @cindex reproducibility, checking
5351 Rebuild @var{package-or-derivation}, which are already available in the
5352 store, and raise an error if the build results are not bit-for-bit
5355 This mechanism allows you to check whether previously installed
5356 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5357 of a package is deterministic. @xref{Invoking guix challenge}, for more
5358 background information and tools.
5360 When used in conjunction with @option{--keep-failed}, the differing
5361 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5362 This makes it easy to look for differences between the two results.
5365 @cindex repairing store items
5366 @cindex corruption, recovering from
5367 Attempt to repair the specified store items, if they are corrupt, by
5368 re-downloading or rebuilding them.
5370 This operation is not atomic and thus restricted to @code{root}.
5374 Return the derivation paths, not the output paths, of the given
5377 @item --root=@var{file}
5378 @itemx -r @var{file}
5379 Make @var{file} a symlink to the result, and register it as a garbage
5383 Return the build log file names or URLs for the given
5384 @var{package-or-derivation}, or raise an error if build logs are
5387 This works regardless of how packages or derivations are specified. For
5388 instance, the following invocations are equivalent:
5391 guix build --log-file `guix build -d guile`
5392 guix build --log-file `guix build guile`
5393 guix build --log-file guile
5394 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5397 If a log is unavailable locally, and unless @code{--no-substitutes} is
5398 passed, the command looks for a corresponding log on one of the
5399 substitute servers (as specified with @code{--substitute-urls}.)
5401 So for instance, imagine you want to see the build log of GDB on MIPS,
5402 but you are actually on an @code{x86_64} machine:
5405 $ guix build --log-file gdb -s mips64el-linux
5406 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5409 You can freely access a huge library of build logs!
5412 @node Debugging Build Failures
5413 @subsection Debugging Build Failures
5415 @cindex build failures, debugging
5416 When defining a new package (@pxref{Defining Packages}), you will
5417 probably find yourself spending some time debugging and tweaking the
5418 build until it succeeds. To do that, you need to operate the build
5419 commands yourself in an environment as close as possible to the one the
5422 To that end, the first thing to do is to use the @option{--keep-failed}
5423 or @option{-K} option of @command{guix build}, which will keep the
5424 failed build tree in @file{/tmp} or whatever directory you specified as
5425 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5427 From there on, you can @command{cd} to the failed build tree and source
5428 the @file{environment-variables} file, which contains all the
5429 environment variable definitions that were in place when the build
5430 failed. So let's say you're debugging a build failure in package
5431 @code{foo}; a typical session would look like this:
5435 @dots{} @i{build fails}
5436 $ cd /tmp/guix-build-foo.drv-0
5437 $ source ./environment-variables
5441 Now, you can invoke commands as if you were the daemon (almost) and
5442 troubleshoot your build process.
5444 Sometimes it happens that, for example, a package's tests pass when you
5445 run them manually but they fail when the daemon runs them. This can
5446 happen because the daemon runs builds in containers where, unlike in our
5447 environment above, network access is missing, @file{/bin/sh} does not
5448 exist, etc. (@pxref{Build Environment Setup}).
5450 In such cases, you may need to run inspect the build process from within
5451 a container similar to the one the build daemon creates:
5456 $ cd /tmp/guix-build-foo.drv-0
5457 $ guix environment --no-grafts -C foo --ad-hoc strace gdb
5458 [env]# source ./environment-variables
5462 Here, @command{guix environment -C} creates a container and spawns a new
5463 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5464 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5465 the container, which would may find handy while debugging. The
5466 @option{--no-grafts} option makes sure we get the exact same
5467 environment, with ungrafted packages (@pxref{Security Updates}, for more
5470 To get closer to a container like that used by the build daemon, we can
5471 remove @file{/bin/sh}:
5477 (Don't worry, this is harmless: this is all happening in the throw-away
5478 container created by @command{guix environment}.)
5480 The @command{strace} command is probably not in the search path, but we
5484 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5487 In this way, not only you will have reproduced the environment variables
5488 the daemon uses, you will also be running the build process in a container
5489 similar to the one the daemon uses.
5492 @node Invoking guix edit
5493 @section Invoking @command{guix edit}
5495 @cindex @command{guix edit}
5496 @cindex package definition, editing
5497 So many packages, so many source files! The @command{guix edit} command
5498 facilitates the life of users and packagers by pointing their editor at
5499 the source file containing the definition of the specified packages.
5503 guix edit gcc@@4.9 vim
5507 launches the program specified in the @code{VISUAL} or in the
5508 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5511 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5512 have created your own packages on @code{GUIX_PACKAGE_PATH}
5513 (@pxref{Defining Packages}), you will be able to edit the package
5514 recipes. Otherwise, you will be able to examine the read-only recipes
5515 for packages currently in the store.
5518 @node Invoking guix download
5519 @section Invoking @command{guix download}
5521 @cindex @command{guix download}
5522 @cindex downloading package sources
5523 When writing a package definition, developers typically need to download
5524 a source tarball, compute its SHA256 hash, and write that
5525 hash in the package definition (@pxref{Defining Packages}). The
5526 @command{guix download} tool helps with this task: it downloads a file
5527 from the given URI, adds it to the store, and prints both its file name
5528 in the store and its SHA256 hash.
5530 The fact that the downloaded file is added to the store saves bandwidth:
5531 when the developer eventually tries to build the newly defined package
5532 with @command{guix build}, the source tarball will not have to be
5533 downloaded again because it is already in the store. It is also a
5534 convenient way to temporarily stash files, which may be deleted
5535 eventually (@pxref{Invoking guix gc}).
5537 The @command{guix download} command supports the same URIs as used in
5538 package definitions. In particular, it supports @code{mirror://} URIs.
5539 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5540 Guile bindings for GnuTLS are available in the user's environment; when
5541 they are not available, an error is raised. @xref{Guile Preparations,
5542 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5543 GnuTLS-Guile}, for more information.
5545 @command{guix download} verifies HTTPS server certificates by loading
5546 the certificates of X.509 authorities from the directory pointed to by
5547 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5548 Certificates}), unless @option{--no-check-certificate} is used.
5550 The following options are available:
5553 @item --format=@var{fmt}
5555 Write the hash in the format specified by @var{fmt}. For more
5556 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5558 @item --no-check-certificate
5559 Do not validate the X.509 certificates of HTTPS servers.
5561 When using this option, you have @emph{absolutely no guarantee} that you
5562 are communicating with the authentic server responsible for the given
5563 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5565 @item --output=@var{file}
5566 @itemx -o @var{file}
5567 Save the downloaded file to @var{file} instead of adding it to the
5571 @node Invoking guix hash
5572 @section Invoking @command{guix hash}
5574 @cindex @command{guix hash}
5575 The @command{guix hash} command computes the SHA256 hash of a file.
5576 It is primarily a convenience tool for anyone contributing to the
5577 distribution: it computes the cryptographic hash of a file, which can be
5578 used in the definition of a package (@pxref{Defining Packages}).
5580 The general syntax is:
5583 guix hash @var{option} @var{file}
5586 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5587 hash of data read from standard input. @command{guix hash} has the
5592 @item --format=@var{fmt}
5594 Write the hash in the format specified by @var{fmt}.
5596 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5597 (@code{hex} and @code{hexadecimal} can be used as well).
5599 If the @option{--format} option is not specified, @command{guix hash}
5600 will output the hash in @code{nix-base32}. This representation is used
5601 in the definitions of packages.
5605 Compute the hash on @var{file} recursively.
5607 In this case, the hash is computed on an archive containing @var{file},
5608 including its children if it is a directory. Some of the metadata of
5609 @var{file} is part of the archive; for instance, when @var{file} is a
5610 regular file, the hash is different depending on whether @var{file} is
5611 executable or not. Metadata such as time stamps has no impact on the
5612 hash (@pxref{Invoking guix archive}).
5613 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5618 When combined with @option{--recursive}, exclude version control system
5619 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5622 As an example, here is how you would compute the hash of a Git checkout,
5623 which is useful when using the @code{git-fetch} method (@pxref{origin
5627 $ git clone http://example.org/foo.git
5633 @node Invoking guix import
5634 @section Invoking @command{guix import}
5636 @cindex importing packages
5637 @cindex package import
5638 @cindex package conversion
5639 @cindex Invoking @command{guix import}
5640 The @command{guix import} command is useful for people who would like to
5641 add a package to the distribution with as little work as
5642 possible---a legitimate demand. The command knows of a few
5643 repositories from which it can ``import'' package metadata. The result
5644 is a package definition, or a template thereof, in the format we know
5645 (@pxref{Defining Packages}).
5647 The general syntax is:
5650 guix import @var{importer} @var{options}@dots{}
5653 @var{importer} specifies the source from which to import package
5654 metadata, and @var{options} specifies a package identifier and other
5655 options specific to @var{importer}. Currently, the available
5660 Import metadata for the given GNU package. This provides a template
5661 for the latest version of that GNU package, including the hash of its
5662 source tarball, and its canonical synopsis and description.
5664 Additional information such as the package dependencies and its
5665 license needs to be figured out manually.
5667 For example, the following command returns a package definition for
5671 guix import gnu hello
5674 Specific command-line options are:
5677 @item --key-download=@var{policy}
5678 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5679 keys when verifying the package signature. @xref{Invoking guix
5680 refresh, @code{--key-download}}.
5685 Import metadata from the @uref{https://pypi.python.org/, Python Package
5686 Index}@footnote{This functionality requires Guile-JSON to be installed.
5687 @xref{Requirements}.}. Information is taken from the JSON-formatted
5688 description available at @code{pypi.python.org} and usually includes all
5689 the relevant information, including package dependencies. For maximum
5690 efficiency, it is recommended to install the @command{unzip} utility, so
5691 that the importer can unzip Python wheels and gather data from them.
5693 The command below imports metadata for the @code{itsdangerous} Python
5697 guix import pypi itsdangerous
5702 Import metadata from @uref{https://rubygems.org/,
5703 RubyGems}@footnote{This functionality requires Guile-JSON to be
5704 installed. @xref{Requirements}.}. Information is taken from the
5705 JSON-formatted description available at @code{rubygems.org} and includes
5706 most relevant information, including runtime dependencies. There are
5707 some caveats, however. The metadata doesn't distinguish between
5708 synopses and descriptions, so the same string is used for both fields.
5709 Additionally, the details of non-Ruby dependencies required to build
5710 native extensions is unavailable and left as an exercise to the
5713 The command below imports metadata for the @code{rails} Ruby package:
5716 guix import gem rails
5721 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5722 functionality requires Guile-JSON to be installed.
5723 @xref{Requirements}.}.
5724 Information is taken from the JSON-formatted metadata provided through
5725 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5726 relevant information, such as module dependencies. License information
5727 should be checked closely. If Perl is available in the store, then the
5728 @code{corelist} utility will be used to filter core modules out of the
5729 list of dependencies.
5731 The command command below imports metadata for the @code{Acme::Boolean}
5735 guix import cpan Acme::Boolean
5740 @cindex Bioconductor
5741 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5742 central repository for the @uref{http://r-project.org, GNU@tie{}R
5743 statistical and graphical environment}.
5745 Information is extracted from the @code{DESCRIPTION} file of the package.
5747 The command command below imports metadata for the @code{Cairo}
5751 guix import cran Cairo
5754 When @code{--recursive} is added, the importer will traverse the
5755 dependency graph of the given upstream package recursively and generate
5756 package expressions for all those packages that are not yet in Guix.
5758 When @code{--archive=bioconductor} is added, metadata is imported from
5759 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5760 packages for for the analysis and comprehension of high-throughput
5761 genomic data in bioinformatics.
5763 Information is extracted from the @code{DESCRIPTION} file of a package
5764 published on the web interface of the Bioconductor SVN repository.
5766 The command below imports metadata for the @code{GenomicRanges}
5770 guix import cran --archive=bioconductor GenomicRanges
5776 Import metadata from @uref{http://www.ctan.org/, CTAN}, the
5777 comprehensive TeX archive network for TeX packages that are part of the
5778 @uref{https://www.tug.org/texlive/, TeX Live distribution}.
5780 Information about the package is obtained through the XML API provided
5781 by CTAN, while the source code is downloaded from the SVN repository of
5782 the Tex Live project. This is done because the CTAN does not keep
5785 The command command below imports metadata for the @code{fontspec}
5789 guix import texlive fontspec
5792 When @code{--archive=DIRECTORY} is added, the source code is downloaded
5793 not from the @file{latex} sub-directory of the @file{texmf-dist/source}
5794 tree in the TeX Live SVN repository, but from the specified sibling
5795 directory under the same root.
5797 The command below imports metadata for the @code{ifxetex} package from
5798 CTAN while fetching the sources from the directory
5799 @file{texmf/source/generic}:
5802 guix import texlive --archive=generic ifxetex
5806 Import metadata from a local copy of the source of the
5807 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5808 relies on the @command{nix-instantiate} command of
5809 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5810 typically written in a mixture of Nix-language and Bash code. This
5811 command only imports the high-level package structure that is written in
5812 the Nix language. It normally includes all the basic fields of a
5815 When importing a GNU package, the synopsis and descriptions are replaced
5816 by their canonical upstream variant.
5818 Usually, you will first need to do:
5821 export NIX_REMOTE=daemon
5825 so that @command{nix-instantiate} does not try to open the Nix database.
5827 As an example, the command below imports the package definition of
5828 LibreOffice (more precisely, it imports the definition of the package
5829 bound to the @code{libreoffice} top-level attribute):
5832 guix import nix ~/path/to/nixpkgs libreoffice
5837 Import metadata from the Haskell community's central package archive
5838 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5839 Cabal files and includes all the relevant information, including package
5842 Specific command-line options are:
5847 Read a Cabal file from standard input.
5848 @item --no-test-dependencies
5850 Do not include dependencies required only by the test suites.
5851 @item --cabal-environment=@var{alist}
5852 @itemx -e @var{alist}
5853 @var{alist} is a Scheme alist defining the environment in which the
5854 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5855 @code{arch}, @code{impl} and a string representing the name of a flag.
5856 The value associated with a flag has to be either the symbol
5857 @code{true} or @code{false}. The value associated with other keys
5858 has to conform to the Cabal file format definition. The default value
5859 associated with the keys @code{os}, @code{arch} and @code{impl} is
5860 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5863 The command below imports metadata for the latest version of the
5864 @code{HTTP} Haskell package without including test dependencies and
5865 specifying the value of the flag @samp{network-uri} as @code{false}:
5868 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5871 A specific package version may optionally be specified by following the
5872 package name by an at-sign and a version number as in the following example:
5875 guix import hackage mtl@@2.1.3.1
5880 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5881 It takes a package name, looks up the package version included in a
5882 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5883 release and uses the @code{hackage} importer to retrieve its metadata.
5884 Note that it is up to you to select an LTS release compatible with the
5885 GHC compiler used by Guix.
5887 Specific command-line options are:
5890 @item --no-test-dependencies
5892 Do not include dependencies required only by the test suites.
5893 @item --lts-version=@var{version}
5894 @itemx -r @var{version}
5895 @var{version} is the desired LTS release version. If omitted the latest
5899 The command below imports metadata for the @code{HTTP} Haskell package
5900 included in the LTS Stackage release version 7.18:
5903 guix import stackage --lts-version=7.18 HTTP
5908 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5909 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5911 Specific command-line options are:
5914 @item --archive=@var{repo}
5915 @itemx -a @var{repo}
5916 @var{repo} identifies the archive repository from which to retrieve the
5917 information. Currently the supported repositories and their identifiers
5921 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5922 identifier. This is the default.
5924 Packages from @code{elpa.gnu.org} are signed with one of the keys
5925 contained in the GnuPG keyring at
5926 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5927 @code{emacs} package (@pxref{Package Installation, ELPA package
5928 signatures,, emacs, The GNU Emacs Manual}).
5931 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5932 @code{melpa-stable} identifier.
5935 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5942 Import metadata from the crates.io Rust package repository
5943 @uref{https://crates.io, crates.io}.
5946 The structure of the @command{guix import} code is modular. It would be
5947 useful to have more importers for other package formats, and your help
5948 is welcome here (@pxref{Contributing}).
5950 @node Invoking guix refresh
5951 @section Invoking @command{guix refresh}
5953 @cindex @command {guix refresh}
5954 The primary audience of the @command{guix refresh} command is developers
5955 of the GNU software distribution. By default, it reports any packages
5956 provided by the distribution that are outdated compared to the latest
5957 upstream version, like this:
5961 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5962 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5965 Alternately, one can specify packages to consider, in which case a
5966 warning is emitted for packages that lack an updater:
5969 $ guix refresh coreutils guile guile-ssh
5970 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5971 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5974 @command{guix refresh} browses the upstream repository of each package and determines
5975 the highest version number of the releases therein. The command
5976 knows how to update specific types of packages: GNU packages, ELPA
5977 packages, etc.---see the documentation for @option{--type} below. There
5978 are many packages, though, for which it lacks a method to determine
5979 whether a new upstream release is available. However, the mechanism is
5980 extensible, so feel free to get in touch with us to add a new method!
5982 When passed @code{--update}, it modifies distribution source files to
5983 update the version numbers and source tarball hashes of those package
5984 recipes (@pxref{Defining Packages}). This is achieved by downloading
5985 each package's latest source tarball and its associated OpenPGP
5986 signature, authenticating the downloaded tarball against its signature
5987 using @command{gpg}, and finally computing its hash. When the public
5988 key used to sign the tarball is missing from the user's keyring, an
5989 attempt is made to automatically retrieve it from a public key server;
5990 when this is successful, the key is added to the user's keyring; otherwise,
5991 @command{guix refresh} reports an error.
5993 The following options are supported:
5997 @item --expression=@var{expr}
5998 @itemx -e @var{expr}
5999 Consider the package @var{expr} evaluates to.
6001 This is useful to precisely refer to a package, as in this example:
6004 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
6007 This command lists the dependents of the ``final'' libc (essentially all
6012 Update distribution source files (package recipes) in place. This is
6013 usually run from a checkout of the Guix source tree (@pxref{Running
6014 Guix Before It Is Installed}):
6017 $ ./pre-inst-env guix refresh -s non-core -u
6020 @xref{Defining Packages}, for more information on package definitions.
6022 @item --select=[@var{subset}]
6023 @itemx -s @var{subset}
6024 Select all the packages in @var{subset}, one of @code{core} or
6027 The @code{core} subset refers to all the packages at the core of the
6028 distribution---i.e., packages that are used to build ``everything
6029 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
6030 changing one of these packages in the distribution entails a rebuild of
6031 all the others. Thus, such updates are an inconvenience to users in
6032 terms of build time or bandwidth used to achieve the upgrade.
6034 The @code{non-core} subset refers to the remaining packages. It is
6035 typically useful in cases where an update of the core packages would be
6038 @item --manifest=@var{file}
6039 @itemx -m @var{file}
6040 Select all the packages from the manifest in @var{file}. This is useful to
6041 check if any packages of the user manifest can be updated.
6043 @item --type=@var{updater}
6044 @itemx -t @var{updater}
6045 Select only packages handled by @var{updater} (may be a comma-separated
6046 list of updaters). Currently, @var{updater} may be one of:
6050 the updater for GNU packages;
6052 the updater for GNOME packages;
6054 the updater for KDE packages;
6056 the updater for X.org packages;
6058 the updater for packages hosted on kernel.org;
6060 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
6062 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
6064 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
6066 the updater for @uref{http://www.cpan.org/, CPAN} packages;
6068 the updater for @uref{https://pypi.python.org, PyPI} packages.
6070 the updater for @uref{https://rubygems.org, RubyGems} packages.
6072 the updater for @uref{https://github.com, GitHub} packages.
6074 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
6076 the updater for @uref{https://www.stackage.org, Stackage} packages.
6078 the updater for @uref{https://crates.io, Crates} packages.
6081 For instance, the following command only checks for updates of Emacs
6082 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
6085 $ guix refresh --type=elpa,cran
6086 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
6087 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
6092 In addition, @command{guix refresh} can be passed one or more package
6093 names, as in this example:
6096 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
6100 The command above specifically updates the @code{emacs} and
6101 @code{idutils} packages. The @code{--select} option would have no
6102 effect in this case.
6104 When considering whether to upgrade a package, it is sometimes
6105 convenient to know which packages would be affected by the upgrade and
6106 should be checked for compatibility. For this the following option may
6107 be used when passing @command{guix refresh} one or more package names:
6111 @item --list-updaters
6113 List available updaters and exit (see @option{--type} above.)
6115 For each updater, display the fraction of packages it covers; at the
6116 end, display the fraction of packages covered by all these updaters.
6118 @item --list-dependent
6120 List top-level dependent packages that would need to be rebuilt as a
6121 result of upgrading one or more packages.
6123 @xref{Invoking guix graph, the @code{reverse-package} type of
6124 @command{guix graph}}, for information on how to visualize the list of
6125 dependents of a package.
6129 Be aware that the @code{--list-dependent} option only
6130 @emph{approximates} the rebuilds that would be required as a result of
6131 an upgrade. More rebuilds might be required under some circumstances.
6134 $ guix refresh --list-dependent flex
6135 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
6136 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
6139 The command above lists a set of packages that could be built to check
6140 for compatibility with an upgraded @code{flex} package.
6142 The following options can be used to customize GnuPG operation:
6146 @item --gpg=@var{command}
6147 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
6148 for in @code{$PATH}.
6150 @item --key-download=@var{policy}
6151 Handle missing OpenPGP keys according to @var{policy}, which may be one
6156 Always download missing OpenPGP keys from the key server, and add them
6157 to the user's GnuPG keyring.
6160 Never try to download missing OpenPGP keys. Instead just bail out.
6163 When a package signed with an unknown OpenPGP key is encountered, ask
6164 the user whether to download it or not. This is the default behavior.
6167 @item --key-server=@var{host}
6168 Use @var{host} as the OpenPGP key server when importing a public key.
6172 The @code{github} updater uses the
6173 @uref{https://developer.github.com/v3/, GitHub API} to query for new
6174 releases. When used repeatedly e.g. when refreshing all packages,
6175 GitHub will eventually refuse to answer any further API requests. By
6176 default 60 API requests per hour are allowed, and a full refresh on all
6177 GitHub packages in Guix requires more than this. Authentication with
6178 GitHub through the use of an API token alleviates these limits. To use
6179 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
6180 token procured from @uref{https://github.com/settings/tokens} or
6184 @node Invoking guix lint
6185 @section Invoking @command{guix lint}
6187 @cindex @command{guix lint}
6188 @cindex package, checking for errors
6189 The @command{guix lint} command is meant to help package developers avoid
6190 common errors and use a consistent style. It runs a number of checks on
6191 a given set of packages in order to find common mistakes in their
6192 definitions. Available @dfn{checkers} include (see
6193 @code{--list-checkers} for a complete list):
6198 Validate certain typographical and stylistic rules about package
6199 descriptions and synopses.
6201 @item inputs-should-be-native
6202 Identify inputs that should most likely be native inputs.
6207 @itemx source-file-name
6208 Probe @code{home-page} and @code{source} URLs and report those that are
6209 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6210 the source file name is meaningful, e.g. is not
6211 just a version number or ``git-checkout'', without a declared
6212 @code{file-name} (@pxref{origin Reference}).
6215 @cindex security vulnerabilities
6216 @cindex CVE, Common Vulnerabilities and Exposures
6217 Report known vulnerabilities found in the Common Vulnerabilities and
6218 Exposures (CVE) databases of the current and past year
6219 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6222 To view information about a particular vulnerability, visit pages such as:
6226 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6228 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6232 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6233 @code{CVE-2015-7554}.
6235 Package developers can specify in package recipes the
6236 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6237 name and version of the package when they differ from the name that Guix
6238 uses, as in this example:
6244 ;; CPE calls this package "grub2".
6245 (properties '((cpe-name . "grub2"))))
6249 Warn about obvious source code formatting issues: trailing white space,
6250 use of tabulations, etc.
6253 The general syntax is:
6256 guix lint @var{options} @var{package}@dots{}
6259 If no package is given on the command line, then all packages are checked.
6260 The @var{options} may be zero or more of the following:
6263 @item --list-checkers
6265 List and describe all the available checkers that will be run on packages
6270 Only enable the checkers specified in a comma-separated list using the
6271 names returned by @code{--list-checkers}.
6275 @node Invoking guix size
6276 @section Invoking @command{guix size}
6279 @cindex package size
6281 @cindex @command{guix size}
6282 The @command{guix size} command helps package developers profile the
6283 disk usage of packages. It is easy to overlook the impact of an
6284 additional dependency added to a package, or the impact of using a
6285 single output for a package that could easily be split (@pxref{Packages
6286 with Multiple Outputs}). Such are the typical issues that
6287 @command{guix size} can highlight.
6289 The command can be passed a package specification such as @code{gcc@@4.8}
6290 or @code{guile:debug}, or a file name in the store. Consider this
6294 $ guix size coreutils
6295 store item total self
6296 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6297 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6298 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6299 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6300 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6301 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6305 The store items listed here constitute the @dfn{transitive closure} of
6306 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6307 would be returned by:
6310 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6313 Here the output shows three columns next to store items. The first column,
6314 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6315 the store item---that is, its own size plus the size of all its
6316 dependencies. The next column, labeled ``self'', shows the size of the
6317 item itself. The last column shows the ratio of the size of the item
6318 itself to the space occupied by all the items listed here.
6320 In this example, we see that the closure of Coreutils weighs in at
6321 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6322 large fraction of the closure is not a problem @i{per se} because it is
6323 always available on the system anyway.)
6325 When the package passed to @command{guix size} is available in the
6326 store, @command{guix size} queries the daemon to determine its
6327 dependencies, and measures its size in the store, similar to @command{du
6328 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6331 When the given package is @emph{not} in the store, @command{guix size}
6332 reports information based on the available substitutes
6333 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6334 store items that are not even on disk, only available remotely.
6336 You can also specify several package names:
6339 $ guix size coreutils grep sed bash
6340 store item total self
6341 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6342 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6343 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6344 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6350 In this example we see that the combination of the four packages takes
6351 102.3@tie{}MiB in total, which is much less than the sum of each closure
6352 since they have a lot of dependencies in common.
6354 The available options are:
6358 @item --substitute-urls=@var{urls}
6359 Use substitute information from @var{urls}.
6360 @xref{client-substitute-urls, the same option for @code{guix build}}.
6362 @item --sort=@var{key}
6363 Sort lines according to @var{key}, one of the following options:
6367 the total size of the item's closure (the default);
6369 the size of each item.
6372 @item --map-file=@var{file}
6373 Write a graphical map of disk usage in PNG format to @var{file}.
6375 For the example above, the map looks like this:
6377 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6378 produced by @command{guix size}}
6380 This option requires that
6381 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6382 installed and visible in Guile's module search path. When that is not
6383 the case, @command{guix size} fails as it tries to load it.
6385 @item --system=@var{system}
6386 @itemx -s @var{system}
6387 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6391 @node Invoking guix graph
6392 @section Invoking @command{guix graph}
6395 @cindex @command{guix graph}
6396 @cindex package dependencies
6397 Packages and their dependencies form a @dfn{graph}, specifically a
6398 directed acyclic graph (DAG). It can quickly become difficult to have a
6399 mental model of the package DAG, so the @command{guix graph} command
6400 provides a visual representation of the DAG. By default,
6401 @command{guix graph} emits a DAG representation in the input format of
6402 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6403 directly to the @command{dot} command of Graphviz. It can also emit an
6404 HTML page with embedded JavaScript code to display a ``chord diagram''
6405 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6406 emit Cypher queries to construct a graph in a graph database supporting
6407 the @uref{http://www.opencypher.org/, openCypher} query language.
6408 The general syntax is:
6411 guix graph @var{options} @var{package}@dots{}
6414 For example, the following command generates a PDF file representing the
6415 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6419 guix graph coreutils | dot -Tpdf > dag.pdf
6422 The output looks like this:
6424 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6426 Nice little graph, no?
6428 But there is more than one graph! The one above is concise: it is the
6429 graph of package objects, omitting implicit inputs such as GCC, libc,
6430 grep, etc. It is often useful to have such a concise graph, but
6431 sometimes one may want to see more details. @command{guix graph} supports
6432 several types of graphs, allowing you to choose the level of detail:
6436 This is the default type used in the example above. It shows the DAG of
6437 package objects, excluding implicit dependencies. It is concise, but
6438 filters out many details.
6440 @item reverse-package
6441 This shows the @emph{reverse} DAG of packages. For example:
6444 guix graph --type=reverse-package ocaml
6447 ... yields the graph of packages that depend on OCaml.
6449 Note that for core packages this can yield huge graphs. If all you want
6450 is to know the number of packages that depend on a given package, use
6451 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6452 @option{--list-dependent}}).
6455 This is the package DAG, @emph{including} implicit inputs.
6457 For instance, the following command:
6460 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6463 ... yields this bigger graph:
6465 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6467 At the bottom of the graph, we see all the implicit inputs of
6468 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6470 Now, note that the dependencies of these implicit inputs---that is, the
6471 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6472 here, for conciseness.
6475 Similar to @code{bag-emerged}, but this time including all the bootstrap
6478 @item bag-with-origins
6479 Similar to @code{bag}, but also showing origins and their dependencies.
6482 This is the most detailed representation: It shows the DAG of
6483 derivations (@pxref{Derivations}) and plain store items. Compared to
6484 the above representation, many additional nodes are visible, including
6485 build scripts, patches, Guile modules, etc.
6487 For this type of graph, it is also possible to pass a @file{.drv} file
6488 name instead of a package name, as in:
6491 guix graph -t derivation `guix system build -d my-config.scm`
6495 All the types above correspond to @emph{build-time dependencies}. The
6496 following graph type represents the @emph{run-time dependencies}:
6500 This is the graph of @dfn{references} of a package output, as returned
6501 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6503 If the given package output is not available in the store, @command{guix
6504 graph} attempts to obtain dependency information from substitutes.
6506 Here you can also pass a store file name instead of a package name. For
6507 example, the command below produces the reference graph of your profile
6508 (which can be big!):
6511 guix graph -t references `readlink -f ~/.guix-profile`
6515 This is the graph of the @dfn{referrers} of a store item, as returned by
6516 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6518 This relies exclusively on local information from your store. For
6519 instance, let us suppose that the current Inkscape is available in 10
6520 profiles on your machine; @command{guix graph -t referrers inkscape}
6521 will show a graph rooted at Inkscape and with those 10 profiles linked
6524 It can help determine what is preventing a store item from being garbage
6529 The available options are the following:
6532 @item --type=@var{type}
6533 @itemx -t @var{type}
6534 Produce a graph output of @var{type}, where @var{type} must be one of
6535 the values listed above.
6538 List the supported graph types.
6540 @item --backend=@var{backend}
6541 @itemx -b @var{backend}
6542 Produce a graph using the selected @var{backend}.
6544 @item --list-backends
6545 List the supported graph backends.
6547 Currently, the available backends are Graphviz and d3.js.
6549 @item --expression=@var{expr}
6550 @itemx -e @var{expr}
6551 Consider the package @var{expr} evaluates to.
6553 This is useful to precisely refer to a package, as in this example:
6556 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6561 @node Invoking guix environment
6562 @section Invoking @command{guix environment}
6564 @cindex reproducible build environments
6565 @cindex development environments
6566 @cindex @command{guix environment}
6567 @cindex environment, package build environment
6568 The purpose of @command{guix environment} is to assist hackers in
6569 creating reproducible development environments without polluting their
6570 package profile. The @command{guix environment} tool takes one or more
6571 packages, builds all of their inputs, and creates a shell
6572 environment to use them.
6574 The general syntax is:
6577 guix environment @var{options} @var{package}@dots{}
6580 The following example spawns a new shell set up for the development of
6584 guix environment guile
6587 If the needed dependencies are not built yet, @command{guix environment}
6588 automatically builds them. The environment of the new shell is an augmented
6589 version of the environment that @command{guix environment} was run in.
6590 It contains the necessary search paths for building the given package
6591 added to the existing environment variables. To create a ``pure''
6592 environment, in which the original environment variables have been unset,
6593 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6594 environment variables such as @code{PATH} in their @file{~/.bashrc}
6595 file. As a consequence, when @code{guix environment} launches it, Bash
6596 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6597 environment variables. It is an error to define such environment
6598 variables in @file{.bashrc}; instead, they should be defined in
6599 @file{.bash_profile}, which is sourced only by log-in shells.
6600 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6601 details on Bash start-up files.}.
6603 @vindex GUIX_ENVIRONMENT
6604 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6605 variable in the shell it spawns; its value is the file name of the
6606 profile of this environment. This allows users to, say, define a
6607 specific prompt for development environments in their @file{.bashrc}
6608 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6611 if [ -n "$GUIX_ENVIRONMENT" ]
6613 export PS1="\u@@\h \w [dev]\$ "
6618 ... or to browse the profile:
6621 $ ls "$GUIX_ENVIRONMENT/bin"
6624 Additionally, more than one package may be specified, in which case the
6625 union of the inputs for the given packages are used. For example, the
6626 command below spawns a shell where all of the dependencies of both Guile
6627 and Emacs are available:
6630 guix environment guile emacs
6633 Sometimes an interactive shell session is not desired. An arbitrary
6634 command may be invoked by placing the @code{--} token to separate the
6635 command from the rest of the arguments:
6638 guix environment guile -- make -j4
6641 In other situations, it is more convenient to specify the list of
6642 packages needed in the environment. For example, the following command
6643 runs @command{python} from an environment containing Python@tie{}2.7 and
6647 guix environment --ad-hoc python2-numpy python-2.7 -- python
6650 Furthermore, one might want the dependencies of a package and also some
6651 additional packages that are not build-time or runtime dependencies, but
6652 are useful when developing nonetheless. Because of this, the
6653 @code{--ad-hoc} flag is positional. Packages appearing before
6654 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6655 added to the environment. Packages appearing after are interpreted as
6656 packages that will be added to the environment directly. For example,
6657 the following command creates a Guix development environment that
6658 additionally includes Git and strace:
6661 guix environment guix --ad-hoc git strace
6664 Sometimes it is desirable to isolate the environment as much as
6665 possible, for maximal purity and reproducibility. In particular, when
6666 using Guix on a host distro that is not GuixSD, it is desirable to
6667 prevent access to @file{/usr/bin} and other system-wide resources from
6668 the development environment. For example, the following command spawns
6669 a Guile REPL in a ``container'' where only the store and the current
6670 working directory are mounted:
6673 guix environment --ad-hoc --container guile -- guile
6677 The @code{--container} option requires Linux-libre 3.19 or newer.
6680 The available options are summarized below.
6683 @item --root=@var{file}
6684 @itemx -r @var{file}
6685 @cindex persistent environment
6686 @cindex garbage collector root, for environments
6687 Make @var{file} a symlink to the profile for this environment, and
6688 register it as a garbage collector root.
6690 This is useful if you want to protect your environment from garbage
6691 collection, to make it ``persistent''.
6693 When this option is omitted, the environment is protected from garbage
6694 collection only for the duration of the @command{guix environment}
6695 session. This means that next time you recreate the same environment,
6696 you could have to rebuild or re-download packages.
6698 @item --expression=@var{expr}
6699 @itemx -e @var{expr}
6700 Create an environment for the package or list of packages that
6701 @var{expr} evaluates to.
6703 For example, running:
6706 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6709 starts a shell with the environment for this specific variant of the
6715 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6718 starts a shell with all the GuixSD base packages available.
6720 The above commands only use the default output of the given packages.
6721 To select other outputs, two element tuples can be specified:
6724 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6727 @item --load=@var{file}
6728 @itemx -l @var{file}
6729 Create an environment for the package or list of packages that the code
6730 within @var{file} evaluates to.
6732 As an example, @var{file} might contain a definition like this
6733 (@pxref{Defining Packages}):
6736 @verbatiminclude environment-gdb.scm
6740 Include all specified packages in the resulting environment, as if an
6741 @i{ad hoc} package were defined with them as inputs. This option is
6742 useful for quickly creating an environment without having to write a
6743 package expression to contain the desired inputs.
6745 For instance, the command:
6748 guix environment --ad-hoc guile guile-sdl -- guile
6751 runs @command{guile} in an environment where Guile and Guile-SDL are
6754 Note that this example implicitly asks for the default output of
6755 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6756 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6757 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6759 This option may be composed with the default behavior of @command{guix
6760 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6761 as packages whose dependencies will be added to the environment, the
6762 default behavior. Packages appearing after are interpreted as packages
6763 that will be added to the environment directly.
6766 Unset existing environment variables when building the new environment.
6767 This has the effect of creating an environment in which search paths
6768 only contain package inputs.
6770 @item --search-paths
6771 Display the environment variable definitions that make up the
6774 @item --system=@var{system}
6775 @itemx -s @var{system}
6776 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6781 Run @var{command} within an isolated container. The current working
6782 directory outside the container is mapped inside the container.
6783 Additionally, a dummy home directory is created that matches the current
6784 user's home directory, and @file{/etc/passwd} is configured accordingly.
6785 The spawned process runs as the current user outside the container, but
6786 has root privileges in the context of the container.
6790 For containers, share the network namespace with the host system.
6791 Containers created without this flag only have access to the loopback
6794 @item --expose=@var{source}[=@var{target}]
6795 For containers, expose the file system @var{source} from the host system
6796 as the read-only file system @var{target} within the container. If
6797 @var{target} is not specified, @var{source} is used as the target mount
6798 point in the container.
6800 The example below spawns a Guile REPL in a container in which the user's
6801 home directory is accessible read-only via the @file{/exchange}
6805 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6808 @item --share=@var{source}[=@var{target}]
6809 For containers, share the file system @var{source} from the host system
6810 as the writable file system @var{target} within the container. If
6811 @var{target} is not specified, @var{source} is used as the target mount
6812 point in the container.
6814 The example below spawns a Guile REPL in a container in which the user's
6815 home directory is accessible for both reading and writing via the
6816 @file{/exchange} directory:
6819 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6823 @command{guix environment}
6824 also supports all of the common build options that @command{guix
6825 build} supports (@pxref{Common Build Options}).
6828 @node Invoking guix publish
6829 @section Invoking @command{guix publish}
6831 @cindex @command{guix publish}
6832 The purpose of @command{guix publish} is to enable users to easily share
6833 their store with others, who can then use it as a substitute server
6834 (@pxref{Substitutes}).
6836 When @command{guix publish} runs, it spawns an HTTP server which allows
6837 anyone with network access to obtain substitutes from it. This means
6838 that any machine running Guix can also act as if it were a build farm,
6839 since the HTTP interface is compatible with Hydra, the software behind
6840 the @code{hydra.gnu.org} build farm.
6842 For security, each substitute is signed, allowing recipients to check
6843 their authenticity and integrity (@pxref{Substitutes}). Because
6844 @command{guix publish} uses the signing key of the system, which is only
6845 readable by the system administrator, it must be started as root; the
6846 @code{--user} option makes it drop root privileges early on.
6848 The signing key pair must be generated before @command{guix publish} is
6849 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6852 The general syntax is:
6855 guix publish @var{options}@dots{}
6858 Running @command{guix publish} without any additional arguments will
6859 spawn an HTTP server on port 8080:
6865 Once a publishing server has been authorized (@pxref{Invoking guix
6866 archive}), the daemon may download substitutes from it:
6869 guix-daemon --substitute-urls=http://example.org:8080
6872 By default, @command{guix publish} compresses archives on the fly as it
6873 serves them. This ``on-the-fly'' mode is convenient in that it requires
6874 no setup and is immediately available. However, when serving lots of
6875 clients, we recommend using the @option{--cache} option, which enables
6876 caching of the archives before they are sent to clients---see below for
6877 details. The @command{guix weather} command provides a handy way to
6878 check what a server provides (@pxref{Invoking guix weather}).
6880 As a bonus, @command{guix publish} also serves as a content-addressed
6881 mirror for source files referenced in @code{origin} records
6882 (@pxref{origin Reference}). For instance, assuming @command{guix
6883 publish} is running on @code{example.org}, the following URL returns the
6884 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6885 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6888 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6891 Obviously, these URLs only work for files that are in the store; in
6892 other cases, they return 404 (``Not Found'').
6894 The following options are available:
6897 @item --port=@var{port}
6898 @itemx -p @var{port}
6899 Listen for HTTP requests on @var{port}.
6901 @item --listen=@var{host}
6902 Listen on the network interface for @var{host}. The default is to
6903 accept connections from any interface.
6905 @item --user=@var{user}
6906 @itemx -u @var{user}
6907 Change privileges to @var{user} as soon as possible---i.e., once the
6908 server socket is open and the signing key has been read.
6910 @item --compression[=@var{level}]
6911 @itemx -C [@var{level}]
6912 Compress data using the given @var{level}. When @var{level} is zero,
6913 disable compression. The range 1 to 9 corresponds to different gzip
6914 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6917 Unless @option{--cache} is used, compression occurs on the fly and
6918 the compressed streams are not
6919 cached. Thus, to reduce load on the machine that runs @command{guix
6920 publish}, it may be a good idea to choose a low compression level, to
6921 run @command{guix publish} behind a caching proxy, or to use
6922 @option{--cache}. Using @option{--cache} has the advantage that it
6923 allows @command{guix publish} to add @code{Content-Length} HTTP header
6926 @item --cache=@var{directory}
6927 @itemx -c @var{directory}
6928 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6929 and only serve archives that are in cache.
6931 When this option is omitted, archives and meta-data are created
6932 on-the-fly. This can reduce the available bandwidth, especially when
6933 compression is enabled, since this may become CPU-bound. Another
6934 drawback of the default mode is that the length of archives is not known
6935 in advance, so @command{guix publish} does not add a
6936 @code{Content-Length} HTTP header to its responses, which in turn
6937 prevents clients from knowing the amount of data being downloaded.
6939 Conversely, when @option{--cache} is used, the first request for a store
6940 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6941 background process to @dfn{bake} the archive---computing its
6942 @code{.narinfo} and compressing the archive, if needed. Once the
6943 archive is cached in @var{directory}, subsequent requests succeed and
6944 are served directly from the cache, which guarantees that clients get
6945 the best possible bandwidth.
6947 The ``baking'' process is performed by worker threads. By default, one
6948 thread per CPU core is created, but this can be customized. See
6949 @option{--workers} below.
6951 When @option{--ttl} is used, cached entries are automatically deleted
6952 when they have expired.
6954 @item --workers=@var{N}
6955 When @option{--cache} is used, request the allocation of @var{N} worker
6956 threads to ``bake'' archives.
6958 @item --ttl=@var{ttl}
6959 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6960 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6961 days, @code{1m} means 1 month, and so on.
6963 This allows the user's Guix to keep substitute information in cache for
6964 @var{ttl}. However, note that @code{guix publish} does not itself
6965 guarantee that the store items it provides will indeed remain available
6966 for as long as @var{ttl}.
6968 Additionally, when @option{--cache} is used, cached entries that have
6969 not been accessed for @var{ttl} and that no longer have a corresponding
6970 item in the store, may be deleted.
6972 @item --nar-path=@var{path}
6973 Use @var{path} as the prefix for the URLs of ``nar'' files
6974 (@pxref{Invoking guix archive, normalized archives}).
6976 By default, nars are served at a URL such as
6977 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6978 change the @code{/nar} part to @var{path}.
6980 @item --public-key=@var{file}
6981 @itemx --private-key=@var{file}
6982 Use the specific @var{file}s as the public/private key pair used to sign
6983 the store items being published.
6985 The files must correspond to the same key pair (the private key is used
6986 for signing and the public key is merely advertised in the signature
6987 metadata). They must contain keys in the canonical s-expression format
6988 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6989 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6990 @file{/etc/guix/signing-key.sec} are used.
6992 @item --repl[=@var{port}]
6993 @itemx -r [@var{port}]
6994 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6995 Reference Manual}) on @var{port} (37146 by default). This is used
6996 primarily for debugging a running @command{guix publish} server.
6999 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
7000 instantiate a @code{guix-publish-service-type} service in the @code{services} field
7001 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
7002 @code{guix-publish-service-type}}).
7004 If you are instead running Guix on a ``foreign distro'', follow these
7009 If your host distro uses the systemd init system:
7012 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
7013 /etc/systemd/system/
7014 # systemctl start guix-publish && systemctl enable guix-publish
7018 If your host distro uses the Upstart init system:
7021 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
7022 # start guix-publish
7026 Otherwise, proceed similarly with your distro's init system.
7029 @node Invoking guix challenge
7030 @section Invoking @command{guix challenge}
7032 @cindex reproducible builds
7033 @cindex verifiable builds
7034 @cindex @command{guix challenge}
7036 Do the binaries provided by this server really correspond to the source
7037 code it claims to build? Is a package build process deterministic?
7038 These are the questions the @command{guix challenge} command attempts to
7041 The former is obviously an important question: Before using a substitute
7042 server (@pxref{Substitutes}), one had better @emph{verify} that it
7043 provides the right binaries, and thus @emph{challenge} it. The latter
7044 is what enables the former: If package builds are deterministic, then
7045 independent builds of the package should yield the exact same result,
7046 bit for bit; if a server provides a binary different from the one
7047 obtained locally, it may be either corrupt or malicious.
7049 We know that the hash that shows up in @file{/gnu/store} file names is
7050 the hash of all the inputs of the process that built the file or
7051 directory---compilers, libraries, build scripts,
7052 etc. (@pxref{Introduction}). Assuming deterministic build processes,
7053 one store file name should map to exactly one build output.
7054 @command{guix challenge} checks whether there is, indeed, a single
7055 mapping by comparing the build outputs of several independent builds of
7056 any given store item.
7058 The command output looks like this:
7061 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
7062 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
7063 updating list of substitutes from 'https://guix.example.org'... 100.0%
7064 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
7065 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7066 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
7067 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
7068 /gnu/store/@dots{}-git-2.5.0 contents differ:
7069 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
7070 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
7071 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
7072 /gnu/store/@dots{}-pius-2.1.1 contents differ:
7073 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7074 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
7075 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
7079 In this example, @command{guix challenge} first scans the store to
7080 determine the set of locally-built derivations---as opposed to store
7081 items that were downloaded from a substitute server---and then queries
7082 all the substitute servers. It then reports those store items for which
7083 the servers obtained a result different from the local build.
7085 @cindex non-determinism, in package builds
7086 As an example, @code{guix.example.org} always gets a different answer.
7087 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
7088 case of Git. This might indicate that the build process of Git is
7089 non-deterministic, meaning that its output varies as a function of
7090 various things that Guix does not fully control, in spite of building
7091 packages in isolated environments (@pxref{Features}). Most common
7092 sources of non-determinism include the addition of timestamps in build
7093 results, the inclusion of random numbers, and directory listings sorted
7094 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
7097 To find out what is wrong with this Git binary, we can do something along
7098 these lines (@pxref{Invoking guix archive}):
7101 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
7102 | guix archive -x /tmp/git
7103 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
7106 This command shows the difference between the files resulting from the
7107 local build, and the files resulting from the build on
7108 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
7109 diffutils, Comparing and Merging Files}). The @command{diff} command
7110 works great for text files. When binary files differ, a better option
7111 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
7112 visualize differences for all kinds of files.
7114 Once you have done that work, you can tell whether the differences are due
7115 to a non-deterministic build process or to a malicious server. We try
7116 hard to remove sources of non-determinism in packages to make it easier
7117 to verify substitutes, but of course, this is a process that
7118 involves not just Guix, but a large part of the free software community.
7119 In the meantime, @command{guix challenge} is one tool to help address
7122 If you are writing packages for Guix, you are encouraged to check
7123 whether @code{hydra.gnu.org} and other substitute servers obtain the
7124 same build result as you did with:
7127 $ guix challenge @var{package}
7131 where @var{package} is a package specification such as
7132 @code{guile@@2.0} or @code{glibc:debug}.
7134 The general syntax is:
7137 guix challenge @var{options} [@var{packages}@dots{}]
7140 When a difference is found between the hash of a locally-built item and
7141 that of a server-provided substitute, or among substitutes provided by
7142 different servers, the command displays it as in the example above and
7143 its exit code is 2 (other non-zero exit codes denote other kinds of
7146 The one option that matters is:
7150 @item --substitute-urls=@var{urls}
7151 Consider @var{urls} the whitespace-separated list of substitute source
7156 Show details about matches (identical contents) in addition to
7157 information about mismatches.
7161 @node Invoking guix copy
7162 @section Invoking @command{guix copy}
7164 @cindex copy, of store items, over SSH
7165 @cindex SSH, copy of store items
7166 @cindex sharing store items across machines
7167 @cindex transferring store items across machines
7168 The @command{guix copy} command copies items from the store of one
7169 machine to that of another machine over a secure shell (SSH)
7170 connection@footnote{This command is available only when Guile-SSH was
7171 found. @xref{Requirements}, for details.}. For example, the following
7172 command copies the @code{coreutils} package, the user's profile, and all
7173 their dependencies over to @var{host}, logged in as @var{user}:
7176 guix copy --to=@var{user}@@@var{host} \
7177 coreutils `readlink -f ~/.guix-profile`
7180 If some of the items to be copied are already present on @var{host},
7181 they are not actually sent.
7183 The command below retrieves @code{libreoffice} and @code{gimp} from
7184 @var{host}, assuming they are available there:
7187 guix copy --from=@var{host} libreoffice gimp
7190 The SSH connection is established using the Guile-SSH client, which is
7191 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
7192 @file{~/.ssh/config}, and uses the SSH agent for authentication.
7194 The key used to sign items that are sent must be accepted by the remote
7195 machine. Likewise, the key used by the remote machine to sign items you
7196 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
7197 own daemon. @xref{Invoking guix archive}, for more information about
7198 store item authentication.
7200 The general syntax is:
7203 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
7206 You must always specify one of the following options:
7209 @item --to=@var{spec}
7210 @itemx --from=@var{spec}
7211 Specify the host to send to or receive from. @var{spec} must be an SSH
7212 spec such as @code{example.org}, @code{charlie@@example.org}, or
7213 @code{charlie@@example.org:2222}.
7216 The @var{items} can be either package names, such as @code{gimp}, or
7217 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7219 When specifying the name of a package to send, it is first built if
7220 needed, unless @option{--dry-run} was specified. Common build options
7221 are supported (@pxref{Common Build Options}).
7224 @node Invoking guix container
7225 @section Invoking @command{guix container}
7227 @cindex @command{guix container}
7229 As of version @value{VERSION}, this tool is experimental. The interface
7230 is subject to radical change in the future.
7233 The purpose of @command{guix container} is to manipulate processes
7234 running within an isolated environment, commonly known as a
7235 ``container'', typically created by the @command{guix environment}
7236 (@pxref{Invoking guix environment}) and @command{guix system container}
7237 (@pxref{Invoking guix system}) commands.
7239 The general syntax is:
7242 guix container @var{action} @var{options}@dots{}
7245 @var{action} specifies the operation to perform with a container, and
7246 @var{options} specifies the context-specific arguments for the action.
7248 The following actions are available:
7252 Execute a command within the context of a running container.
7257 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7260 @var{pid} specifies the process ID of the running container.
7261 @var{program} specifies an executable file name within the root file
7262 system of the container. @var{arguments} are the additional options that
7263 will be passed to @var{program}.
7265 The following command launches an interactive login shell inside a
7266 GuixSD container, started by @command{guix system container}, and whose
7270 guix container exec 9001 /run/current-system/profile/bin/bash --login
7273 Note that the @var{pid} cannot be the parent process of a container. It
7274 must be PID 1 of the container or one of its child processes.
7278 @node Invoking guix weather
7279 @section Invoking @command{guix weather}
7281 Occasionally you're grumpy because substitutes are lacking and you end
7282 up building packages by yourself (@pxref{Substitutes}). The
7283 @command{guix weather} command reports on substitute availability on the
7284 specified servers so you can have an idea of whether you'll be grumpy
7285 today. It can sometimes be useful info as a user, but it is primarily
7286 useful to people running @command{guix publish} (@pxref{Invoking guix
7289 @cindex statistics, for substitutes
7290 @cindex availability of substitutes
7291 @cindex substitute availability
7292 @cindex weather, substitute availability
7293 Here's a sample run:
7296 $ guix weather --substitute-urls=https://guix.example.org
7297 computing 5,872 package derivations for x86_64-linux...
7298 looking for 6,128 store items on https://guix.example.org..
7299 updating list of substitutes from 'https://guix.example.org'... 100.0%
7300 https://guix.example.org
7301 43.4% substitutes available (2,658 out of 6,128)
7302 7,032.5 MiB of nars (compressed)
7303 19,824.2 MiB on disk (uncompressed)
7304 0.030 seconds per request (182.9 seconds in total)
7305 33.5 requests per second
7308 As you can see, it reports the fraction of all the packages for which
7309 substitutes are available on the server---regardless of whether
7310 substitutes are enabled, and regardless of whether this server's signing
7311 key is authorized. It also reports the size of the compressed archives
7312 (``nars'') provided by the server, the size the corresponding store
7313 items occupy in the store (assuming deduplication is turned off), and
7314 the server's throughput.
7316 To achieve that, @command{guix weather} queries over HTTP(S) meta-data
7317 (@dfn{narinfos}) for all the relevant store items. Like @command{guix
7318 challenge}, it ignores signatures on those substitutes, which is
7319 innocuous since the command only gathers statistics and cannot install
7322 Among other things, it is possible to query specific system types and
7323 specific package sets. The available options are listed below.
7326 @item --substitute-urls=@var{urls}
7327 @var{urls} is the space-separated list of substitute server URLs to
7328 query. When this option is omitted, the default set of substitute
7331 @item --system=@var{system}
7332 @itemx -s @var{system}
7333 Query substitutes for @var{system}---e.g., @code{aarch64-linux}. This
7334 option can be repeated, in which case @command{guix weather} will query
7335 substitutes for several system types.
7337 @item --manifest=@var{file}
7338 Instead of querying substitutes for all the packages, only ask for those
7339 specified in @var{file}. @var{file} must contain a @dfn{manifest}, as
7340 with the @code{-m} option of @command{guix package} (@pxref{Invoking
7345 @c *********************************************************************
7346 @node GNU Distribution
7347 @chapter GNU Distribution
7349 @cindex Guix System Distribution
7351 Guix comes with a distribution of the GNU system consisting entirely of
7352 free software@footnote{The term ``free'' here refers to the
7353 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7354 users of that software}.}. The
7355 distribution can be installed on its own (@pxref{System Installation}),
7356 but it is also possible to install Guix as a package manager on top of
7357 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7358 between the two, we refer to the standalone distribution as the Guix
7359 System Distribution, or GuixSD.
7361 The distribution provides core GNU packages such as GNU libc, GCC, and
7362 Binutils, as well as many GNU and non-GNU applications. The complete
7363 list of available packages can be browsed
7364 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7365 running @command{guix package} (@pxref{Invoking guix package}):
7368 guix package --list-available
7371 Our goal is to provide a practical 100% free software distribution of
7372 Linux-based and other variants of GNU, with a focus on the promotion and
7373 tight integration of GNU components, and an emphasis on programs and
7374 tools that help users exert that freedom.
7376 Packages are currently available on the following platforms:
7381 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7384 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7387 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7388 using the EABI hard-float application binary interface (ABI),
7389 and Linux-Libre kernel.
7392 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7393 currently in an experimental stage, with limited support.
7394 @xref{Contributing}, for how to help!
7396 @item mips64el-linux
7397 little-endian 64-bit MIPS processors, specifically the Loongson series,
7398 n32 ABI, and Linux-Libre kernel.
7402 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7405 For information on porting to other architectures or kernels,
7409 * System Installation:: Installing the whole operating system.
7410 * System Configuration:: Configuring the operating system.
7411 * Documentation:: Browsing software user manuals.
7412 * Installing Debugging Files:: Feeding the debugger.
7413 * Security Updates:: Deploying security fixes quickly.
7414 * Package Modules:: Packages from the programmer's viewpoint.
7415 * Packaging Guidelines:: Growing the distribution.
7416 * Bootstrapping:: GNU/Linux built from scratch.
7417 * Porting:: Targeting another platform or kernel.
7420 Building this distribution is a cooperative effort, and you are invited
7421 to join! @xref{Contributing}, for information about how you can help.
7423 @node System Installation
7424 @section System Installation
7426 @cindex installing GuixSD
7427 @cindex Guix System Distribution
7428 This section explains how to install the Guix System Distribution (GuixSD)
7429 on a machine. The Guix package manager can
7430 also be installed on top of a running GNU/Linux system,
7431 @pxref{Installation}.
7435 @c This paragraph is for people reading this from tty2 of the
7436 @c installation image.
7437 You are reading this documentation with an Info reader. For details on
7438 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7439 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7440 Info}. Hit @kbd{l} afterwards to come back here.
7442 Alternately, run @command{info info} in another tty to keep the manual
7448 * Limitations:: What you can expect.
7449 * Hardware Considerations:: Supported hardware.
7450 * USB Stick Installation:: Preparing the installation medium.
7451 * Preparing for Installation:: Networking, partitioning, etc.
7452 * Proceeding with the Installation:: The real thing.
7453 * Installing GuixSD in a VM:: GuixSD playground.
7454 * Building the Installation Image:: How this comes to be.
7458 @subsection Limitations
7460 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7461 not production-ready. It may contain bugs and lack important
7462 features. Thus, if you are looking for a stable production system that
7463 respects your freedom as a computer user, a good solution at this point
7464 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7465 the more established GNU/Linux distributions}. We hope you can soon switch
7466 to the GuixSD without fear, of course. In the meantime, you can
7467 also keep using your distribution and try out the package manager on top
7468 of it (@pxref{Installation}).
7470 Before you proceed with the installation, be aware of the following
7471 noteworthy limitations applicable to version @value{VERSION}:
7475 The installation process does not include a graphical user interface and
7476 requires familiarity with GNU/Linux (see the following subsections to
7477 get a feel of what that means.)
7480 Support for the Logical Volume Manager (LVM) is missing.
7483 More and more system services are provided (@pxref{Services}), but some
7487 More than 5,300 packages are available, but you may
7488 occasionally find that a useful package is missing.
7491 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7492 as well as a number of X11 window managers. However, some graphical
7493 applications may be missing, as well as KDE.
7496 You have been warned! But more than a disclaimer, this is an invitation
7497 to report issues (and success stories!), and to join us in improving it.
7498 @xref{Contributing}, for more info.
7501 @node Hardware Considerations
7502 @subsection Hardware Considerations
7504 @cindex hardware support on GuixSD
7505 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7506 builds around the kernel Linux-libre, which means that only hardware for
7507 which free software drivers and firmware exist is supported. Nowadays,
7508 a wide range of off-the-shelf hardware is supported on
7509 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7510 Ethernet controllers. Unfortunately, there are still areas where
7511 hardware vendors deny users control over their own computing, and such
7512 hardware is not supported on GuixSD.
7514 @cindex WiFi, hardware support
7515 One of the main areas where free drivers or firmware are lacking is WiFi
7516 devices. WiFi devices known to work include those using Atheros chips
7517 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7518 driver, and those using Broadcom/AirForce chips (BCM43xx with
7519 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7520 Linux-libre driver. Free firmware exists for both and is available
7521 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7522 (@pxref{operating-system Reference, @code{firmware}}).
7524 @cindex RYF, Respects Your Freedom
7525 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7526 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7527 certification program for hardware products that respect your freedom
7528 and your privacy and ensure that you have control over your device. We
7529 encourage you to check the list of RYF-certified devices.
7531 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7532 web site. It contains a catalog of hardware devices with information
7533 about their support in GNU/Linux.
7536 @node USB Stick Installation
7537 @subsection USB Stick Installation
7539 An installation image for USB sticks can be downloaded from
7540 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7541 where @var{system} is one of:
7545 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7548 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7551 @c start duplication of authentication part from ``Binary Installation''
7552 Make sure to download the associated @file{.sig} file and to verify the
7553 authenticity of the image against it, along these lines:
7556 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7557 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7560 If that command fails because you do not have the required public key,
7561 then run this command to import it:
7564 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7568 and rerun the @code{gpg --verify} command.
7571 This image contains a single partition with the tools necessary for an
7572 installation. It is meant to be copied @emph{as is} to a large-enough
7575 To copy the image to a USB stick, follow these steps:
7579 Decompress the image using the @command{xz} command:
7582 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7586 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7587 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7588 copy the image with:
7591 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7595 Access to @file{/dev/sdX} usually requires root privileges.
7598 Once this is done, you should be able to reboot the system and boot from
7599 the USB stick. The latter usually requires you to get in the BIOS or
7600 UEFI boot menu, where you can choose to boot from the USB stick.
7602 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7603 GuixSD in a virtual machine (VM).
7605 @node Preparing for Installation
7606 @subsection Preparing for Installation
7608 Once you have successfully booted the image on the USB stick, you should
7609 end up with a root prompt. Several console TTYs are configured and can
7610 be used to run commands as root. TTY2 shows this documentation,
7611 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7612 Stand-alone GNU Info}). The installation system runs the GPM mouse
7613 daemon, which allows you to select text with the left mouse button and
7614 to paste it with the middle button.
7617 Installation requires access to the Internet so that any missing
7618 dependencies of your system configuration can be downloaded. See the
7619 ``Networking'' section below.
7622 The installation system includes many common tools needed for this task.
7623 But it is also a full-blown GuixSD system, which means that you can
7624 install additional packages, should you need it, using @command{guix
7625 package} (@pxref{Invoking guix package}).
7627 @subsubsection Keyboard Layout
7629 @cindex keyboard layout
7630 The installation image uses the US qwerty keyboard layout. If you want
7631 to change it, you can use the @command{loadkeys} command. For example,
7632 the following command selects the Dvorak keyboard layout:
7638 See the files under @file{/run/current-system/profile/share/keymaps} for
7639 a list of available keyboard layouts. Run @command{man loadkeys} for
7642 @subsubsection Networking
7644 Run the following command see what your network interfaces are called:
7651 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7657 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7658 Wired interfaces have a name starting with @samp{e}; for example, the
7659 interface corresponding to the first on-board Ethernet controller is
7660 called @samp{eno1}. Wireless interfaces have a name starting with
7661 @samp{w}, like @samp{w1p2s0}.
7664 @item Wired connection
7665 To configure a wired network run the following command, substituting
7666 @var{interface} with the name of the wired interface you want to use.
7669 ifconfig @var{interface} up
7672 @item Wireless connection
7675 To configure wireless networking, you can create a configuration file
7676 for the @command{wpa_supplicant} configuration tool (its location is not
7677 important) using one of the available text editors such as
7681 zile wpa_supplicant.conf
7684 As an example, the following stanza can go to this file and will work
7685 for many wireless networks, provided you give the actual SSID and
7686 passphrase for the network you are connecting to:
7690 ssid="@var{my-ssid}"
7692 psk="the network's secret passphrase"
7696 Start the wireless service and run it in the background with the
7697 following command (substitute @var{interface} with the name of the
7698 network interface you want to use):
7701 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7704 Run @command{man wpa_supplicant} for more information.
7708 At this point, you need to acquire an IP address. On a network where IP
7709 addresses are automatically assigned @i{via} DHCP, you can run:
7712 dhclient -v @var{interface}
7715 Try to ping a server to see if networking is up and running:
7721 Setting up network access is almost always a requirement because the
7722 image does not contain all the software and tools that may be needed.
7724 @cindex installing over SSH
7725 If you want to, you can continue the installation remotely by starting
7729 herd start ssh-daemon
7732 Make sure to either set a password with @command{passwd}, or configure
7733 OpenSSH public key authentication before logging in.
7735 @subsubsection Disk Partitioning
7737 Unless this has already been done, the next step is to partition, and
7738 then format the target partition(s).
7740 The installation image includes several partitioning tools, including
7741 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7742 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7743 the partition layout you want:
7749 If your disk uses the GUID Partition Table (GPT) format and you plan to
7750 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7751 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7754 @cindex EFI, installation
7755 @cindex UEFI, installation
7756 @cindex ESP, EFI system partition
7757 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7758 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7759 must have the @code{esp} flag set. E.g., for @command{parted}:
7762 parted /dev/sda set 1 esp on
7765 Once you are done partitioning the target hard disk drive, you have to
7766 create a file system on the relevant partition(s)@footnote{Currently
7767 GuixSD only supports ext4 and btrfs file systems. In particular, code
7768 that reads partition UUIDs and labels only works for these file system
7771 Preferably, assign partitions a label so that you can easily and
7772 reliably refer to them in @code{file-system} declarations (@pxref{File
7773 Systems}). This is typically done using the @code{-L} option of
7774 @command{mkfs.ext4} and related commands. So, assuming the target root
7775 partition lives at @file{/dev/sda1}, a file system with the label
7776 @code{my-root} can be created with:
7779 mkfs.ext4 -L my-root /dev/sda1
7782 @cindex encrypted disk
7783 If you are instead planning to encrypt the root partition, you can use
7784 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7785 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7786 @code{man cryptsetup}} for more information.) Assuming you want to
7787 store the root partition on @file{/dev/sda1}, the command sequence would
7788 be along these lines:
7791 cryptsetup luksFormat /dev/sda1
7792 cryptsetup open --type luks /dev/sda1 my-partition
7793 mkfs.ext4 -L my-root /dev/mapper/my-partition
7796 Once that is done, mount the target root partition under @file{/mnt}
7797 with a command like (again, assuming @code{my-root} is the label of the
7801 mount LABEL=my-root /mnt
7804 Also mount any other partitions you would like to use on the target
7805 system relative to this path. If you have @file{/boot} on a separate
7806 partition for example, mount it at @file{/mnt/boot} now so it is found
7807 by @code{guix system init} afterwards.
7809 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7810 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7811 sure to initialize them with @command{mkswap}. Assuming you have one
7812 swap partition on @file{/dev/sda2}, you would run:
7819 Alternatively, you may use a swap file. For example, assuming that in
7820 the new system you want to use the file @file{/swapfile} as a swap file,
7821 you would run@footnote{This example will work for many types of file
7822 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7823 btrfs), the required steps may be different. For details, see the
7824 manual pages for @command{mkswap} and @command{swapon}.}:
7827 # This is 10 GiB of swap space. Adjust "count" to change the size.
7828 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7829 # For security, make the file readable and writable only by root.
7830 chmod 600 /mnt/swapfile
7831 mkswap /mnt/swapfile
7832 swapon /mnt/swapfile
7835 Note that if you have encrypted the root partition and created a swap
7836 file in its file system as described above, then the encryption also
7837 protects the swap file, just like any other file in that file system.
7839 @node Proceeding with the Installation
7840 @subsection Proceeding with the Installation
7842 With the target partitions ready and the target root mounted on
7843 @file{/mnt}, we're ready to go. First, run:
7846 herd start cow-store /mnt
7849 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7850 during the installation phase are written to the target disk on @file{/mnt}
7851 rather than kept in memory. This is necessary because the first phase of
7852 the @command{guix system init} command (see below) entails downloads or
7853 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7855 Next, you have to edit a file and
7856 provide the declaration of the operating system to be installed. To
7857 that end, the installation system comes with three text editors: GNU nano
7858 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7859 nvi (a clone of the original BSD @command{vi} editor).
7860 We strongly recommend storing that file on the target root file system, say,
7861 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7862 configuration file once you have rebooted into the newly-installed system.
7864 @xref{Using the Configuration System}, for an overview of the
7865 configuration file. The example configurations discussed in that
7866 section are available under @file{/etc/configuration} in the
7867 installation image. Thus, to get started with a system configuration
7868 providing a graphical display server (a ``desktop'' system), you can run
7869 something along these lines:
7873 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7874 # zile /mnt/etc/config.scm
7877 You should pay attention to what your configuration file contains, and
7882 Make sure the @code{grub-configuration} form refers to the device you
7883 want to install GRUB on. You also need to specify the @code{grub-efi}
7884 package if you wish to use native UEFI boot.
7887 Be sure that your partition labels match the value of their respective
7888 @code{device} fields in your @code{file-system} configuration, assuming
7889 your @code{file-system} configuration sets the value of @code{title} to
7893 If there are encrypted or RAID partitions, make sure to add a
7894 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7897 Once you are done preparing the configuration file, the new system must
7898 be initialized (remember that the target root file system is mounted
7902 guix system init /mnt/etc/config.scm /mnt
7906 This copies all the necessary files and installs GRUB on
7907 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7908 more information, @pxref{Invoking guix system}. This command may trigger
7909 downloads or builds of missing packages, which can take some time.
7911 Once that command has completed---and hopefully succeeded!---you can run
7912 @command{reboot} and boot into the new system. The @code{root} password
7913 in the new system is initially empty; other users' passwords need to be
7914 initialized by running the @command{passwd} command as @code{root},
7915 unless your configuration specifies otherwise
7916 (@pxref{user-account-password, user account passwords}).
7918 @cindex upgrading GuixSD
7919 From then on, you can update GuixSD whenever you want by running
7920 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7921 then running @command{guix system reconfigure} to build a new system
7922 generation with the latest packages and services (@pxref{Invoking guix
7923 system}). We recommend doing that regularly so that your system
7924 includes the latest security updates (@pxref{Security Updates}).
7926 Join us on @code{#guix} on the Freenode IRC network or on
7927 @file{guix-devel@@gnu.org} to share your experience---good or not so
7930 @node Installing GuixSD in a VM
7931 @subsection Installing GuixSD in a Virtual Machine
7933 @cindex virtual machine, GuixSD installation
7934 @cindex virtual private server (VPS)
7935 @cindex VPS (virtual private server)
7936 If you'd like to install GuixSD in a virtual machine (VM) or on a
7937 virtual private server (VPS) rather than on your beloved machine, this
7940 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7941 disk image, follow these steps:
7945 First, retrieve and decompress the GuixSD installation image as
7946 described previously (@pxref{USB Stick Installation}).
7949 Create a disk image that will hold the installed system. To make a
7950 qcow2-formatted disk image, use the @command{qemu-img} command:
7953 qemu-img create -f qcow2 guixsd.img 50G
7956 The resulting file will be much smaller than 50 GB (typically less than
7957 1 MB), but it will grow as the virtualized storage device is filled up.
7960 Boot the USB installation image in an VM:
7963 qemu-system-x86_64 -m 1024 -smp 1 \
7964 -net user -net nic,model=virtio -boot menu=on \
7965 -drive file=guixsd-usb-install-@value{VERSION}.@var{system} \
7966 -drive file=guixsd.img
7969 The ordering of the drives matters.
7971 In the VM console, quickly press the @kbd{F12} key to enter the boot
7972 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7976 You're now root in the VM, proceed with the installation process.
7977 @xref{Preparing for Installation}, and follow the instructions.
7980 Once installation is complete, you can boot the system that's on your
7981 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7984 @node Building the Installation Image
7985 @subsection Building the Installation Image
7987 @cindex installation image
7988 The installation image described above was built using the @command{guix
7989 system} command, specifically:
7992 guix system disk-image gnu/system/install.scm
7995 Have a look at @file{gnu/system/install.scm} in the source tree,
7996 and see also @ref{Invoking guix system} for more information
7997 about the installation image.
7999 @node System Configuration
8000 @section System Configuration
8002 @cindex system configuration
8003 The Guix System Distribution supports a consistent whole-system configuration
8004 mechanism. By that we mean that all aspects of the global system
8005 configuration---such as the available system services, timezone and
8006 locale settings, user accounts---are declared in a single place. Such
8007 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
8009 One of the advantages of putting all the system configuration under the
8010 control of Guix is that it supports transactional system upgrades, and
8011 makes it possible to roll back to a previous system instantiation,
8012 should something go wrong with the new one (@pxref{Features}). Another
8013 advantage is that it makes it easy to replicate the exact same configuration
8014 across different machines, or at different points in time, without
8015 having to resort to additional administration tools layered on top of
8016 the own tools of the system.
8017 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
8019 This section describes this mechanism. First we focus on the system
8020 administrator's viewpoint---explaining how the system is configured and
8021 instantiated. Then we show how this mechanism can be extended, for
8022 instance to support new system services.
8025 * Using the Configuration System:: Customizing your GNU system.
8026 * operating-system Reference:: Detail of operating-system declarations.
8027 * File Systems:: Configuring file system mounts.
8028 * Mapped Devices:: Block device extra processing.
8029 * User Accounts:: Specifying user accounts.
8030 * Locales:: Language and cultural convention settings.
8031 * Services:: Specifying system services.
8032 * Setuid Programs:: Programs running with root privileges.
8033 * X.509 Certificates:: Authenticating HTTPS servers.
8034 * Name Service Switch:: Configuring libc's name service switch.
8035 * Initial RAM Disk:: Linux-Libre bootstrapping.
8036 * Bootloader Configuration:: Configuring the boot loader.
8037 * Invoking guix system:: Instantiating a system configuration.
8038 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
8039 * Defining Services:: Adding new service definitions.
8042 @node Using the Configuration System
8043 @subsection Using the Configuration System
8045 The operating system is configured by providing an
8046 @code{operating-system} declaration in a file that can then be passed to
8047 the @command{guix system} command (@pxref{Invoking guix system}). A
8048 simple setup, with the default system services, the default Linux-Libre
8049 kernel, initial RAM disk, and boot loader looks like this:
8051 @findex operating-system
8053 @include os-config-bare-bones.texi
8056 This example should be self-describing. Some of the fields defined
8057 above, such as @code{host-name} and @code{bootloader}, are mandatory.
8058 Others, such as @code{packages} and @code{services}, can be omitted, in
8059 which case they get a default value.
8061 Below we discuss the effect of some of the most important fields
8062 (@pxref{operating-system Reference}, for details about all the available
8063 fields), and how to @dfn{instantiate} the operating system using
8064 @command{guix system}.
8066 @unnumberedsubsubsec Globally-Visible Packages
8068 @vindex %base-packages
8069 The @code{packages} field lists packages that will be globally visible
8070 on the system, for all user accounts---i.e., in every user's @code{PATH}
8071 environment variable---in addition to the per-user profiles
8072 (@pxref{Invoking guix package}). The @var{%base-packages} variable
8073 provides all the tools one would expect for basic user and administrator
8074 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
8075 the GNU Zile lightweight text editor, @command{find}, @command{grep},
8076 etc. The example above adds tcpdump to those, taken from the @code{(gnu
8077 packages admin)} module (@pxref{Package Modules}). The
8078 @code{(list package output)} syntax can be used to add a specific output
8082 (use-modules (gnu packages))
8083 (use-modules (gnu packages dns))
8087 (packages (cons (list bind "utils")
8091 @findex specification->package
8092 Referring to packages by variable name, like @var{tcpdump} above, has
8093 the advantage of being unambiguous; it also allows typos and such to be
8094 diagnosed right away as ``unbound variables''. The downside is that one
8095 needs to know which module defines which package, and to augment the
8096 @code{use-package-modules} line accordingly. To avoid that, one can use
8097 the @code{specification->package} procedure of the @code{(gnu packages)}
8098 module, which returns the best package for a given name or name and
8102 (use-modules (gnu packages))
8106 (packages (append (map specification->package
8107 '("tcpdump" "htop" "gnupg@@2.0"))
8111 @unnumberedsubsubsec System Services
8114 @vindex %base-services
8115 The @code{services} field lists @dfn{system services} to be made
8116 available when the system starts (@pxref{Services}).
8117 The @code{operating-system} declaration above specifies that, in
8118 addition to the basic services, we want the @command{lshd} secure shell
8119 daemon listening on port 2222 (@pxref{Networking Services,
8120 @code{lsh-service}}). Under the hood,
8121 @code{lsh-service} arranges so that @code{lshd} is started with the
8122 right command-line options, possibly with supporting configuration files
8123 generated as needed (@pxref{Defining Services}).
8125 @cindex customization, of services
8126 @findex modify-services
8127 Occasionally, instead of using the base services as is, you will want to
8128 customize them. To do this, use @code{modify-services} (@pxref{Service
8129 Reference, @code{modify-services}}) to modify the list.
8131 For example, suppose you want to modify @code{guix-daemon} and Mingetty
8132 (the console log-in) in the @var{%base-services} list (@pxref{Base
8133 Services, @code{%base-services}}). To do that, you can write the
8134 following in your operating system declaration:
8137 (define %my-services
8138 ;; My very own list of services.
8139 (modify-services %base-services
8140 (guix-service-type config =>
8143 (use-substitutes? #f)
8144 (extra-options '("--gc-keep-derivations"))))
8145 (mingetty-service-type config =>
8146 (mingetty-configuration
8147 (inherit config)))))
8151 (services %my-services))
8154 This changes the configuration---i.e., the service parameters---of the
8155 @code{guix-service-type} instance, and that of all the
8156 @code{mingetty-service-type} instances in the @var{%base-services} list.
8157 Observe how this is accomplished: first, we arrange for the original
8158 configuration to be bound to the identifier @code{config} in the
8159 @var{body}, and then we write the @var{body} so that it evaluates to the
8160 desired configuration. In particular, notice how we use @code{inherit}
8161 to create a new configuration which has the same values as the old
8162 configuration, but with a few modifications.
8164 @cindex encrypted disk
8165 The configuration for a typical ``desktop'' usage, with an encrypted
8166 root partition, the X11 display
8167 server, GNOME and Xfce (users can choose which of these desktop
8168 environments to use at the log-in screen by pressing @kbd{F1}), network
8169 management, power management, and more, would look like this:
8172 @include os-config-desktop.texi
8175 A graphical UEFI system with a choice of lightweight window managers
8176 instead of full-blown desktop environments would look like this:
8179 @include os-config-lightweight-desktop.texi
8182 @xref{Desktop Services}, for the exact list of services provided by
8183 @var{%desktop-services}. @xref{X.509 Certificates}, for background
8184 information about the @code{nss-certs} package that is used here.
8186 Again, @var{%desktop-services} is just a list of service objects. If
8187 you want to remove services from there, you can do so using the
8188 procedures for list filtering (@pxref{SRFI-1 Filtering and
8189 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
8190 following expression returns a list that contains all the services in
8191 @var{%desktop-services} minus the Avahi service:
8194 (remove (lambda (service)
8195 (eq? (service-kind service) avahi-service-type))
8199 @unnumberedsubsubsec Instantiating the System
8201 Assuming the @code{operating-system} declaration
8202 is stored in the @file{my-system-config.scm}
8203 file, the @command{guix system reconfigure my-system-config.scm} command
8204 instantiates that configuration, and makes it the default GRUB boot
8205 entry (@pxref{Invoking guix system}).
8207 The normal way to change the system configuration is by updating this
8208 file and re-running @command{guix system reconfigure}. One should never
8209 have to touch files in @file{/etc} or to run commands that modify the
8210 system state such as @command{useradd} or @command{grub-install}. In
8211 fact, you must avoid that since that would not only void your warranty
8212 but also prevent you from rolling back to previous versions of your
8213 system, should you ever need to.
8215 @cindex roll-back, of the operating system
8216 Speaking of roll-back, each time you run @command{guix system
8217 reconfigure}, a new @dfn{generation} of the system is created---without
8218 modifying or deleting previous generations. Old system generations get
8219 an entry in the bootloader boot menu, allowing you to boot them in case
8220 something went wrong with the latest generation. Reassuring, no? The
8221 @command{guix system list-generations} command lists the system
8222 generations available on disk. It is also possible to roll back the
8223 system via the commands @command{guix system roll-back} and
8224 @command{guix system switch-generation}.
8226 Although the command @command{guix system reconfigure} will not modify
8227 previous generations, must take care when the current generation is not
8228 the latest (e.g., after invoking @command{guix system roll-back}), since
8229 the operation might overwrite a later generation (@pxref{Invoking guix
8232 @unnumberedsubsubsec The Programming Interface
8234 At the Scheme level, the bulk of an @code{operating-system} declaration
8235 is instantiated with the following monadic procedure (@pxref{The Store
8238 @deffn {Monadic Procedure} operating-system-derivation os
8239 Return a derivation that builds @var{os}, an @code{operating-system}
8240 object (@pxref{Derivations}).
8242 The output of the derivation is a single directory that refers to all
8243 the packages, configuration files, and other supporting files needed to
8244 instantiate @var{os}.
8247 This procedure is provided by the @code{(gnu system)} module. Along
8248 with @code{(gnu services)} (@pxref{Services}), this module contains the
8249 guts of GuixSD. Make sure to visit it!
8252 @node operating-system Reference
8253 @subsection @code{operating-system} Reference
8255 This section summarizes all the options available in
8256 @code{operating-system} declarations (@pxref{Using the Configuration
8259 @deftp {Data Type} operating-system
8260 This is the data type representing an operating system configuration.
8261 By that, we mean all the global system configuration, not per-user
8262 configuration (@pxref{Using the Configuration System}).
8265 @item @code{kernel} (default: @var{linux-libre})
8266 The package object of the operating system kernel to use@footnote{Currently
8267 only the Linux-libre kernel is supported. In the future, it will be
8268 possible to use the GNU@tie{}Hurd.}.
8270 @item @code{kernel-arguments} (default: @code{'()})
8271 List of strings or gexps representing additional arguments to pass on
8272 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
8274 @item @code{bootloader}
8275 The system bootloader configuration object. @xref{Bootloader Configuration}.
8277 @item @code{initrd} (default: @code{base-initrd})
8279 @cindex initial RAM disk
8280 A two-argument monadic procedure that returns an initial RAM disk for
8281 the Linux kernel. @xref{Initial RAM Disk}.
8283 @item @code{firmware} (default: @var{%base-firmware})
8285 List of firmware packages loadable by the operating system kernel.
8287 The default includes firmware needed for Atheros- and Broadcom-based
8288 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8289 respectively). @xref{Hardware Considerations}, for more info on
8292 @item @code{host-name}
8295 @item @code{hosts-file}
8297 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8298 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8299 Reference Manual}). The default is a file with entries for
8300 @code{localhost} and @var{host-name}.
8302 @item @code{mapped-devices} (default: @code{'()})
8303 A list of mapped devices. @xref{Mapped Devices}.
8305 @item @code{file-systems}
8306 A list of file systems. @xref{File Systems}.
8308 @item @code{swap-devices} (default: @code{'()})
8309 @cindex swap devices
8310 A list of strings identifying devices or files to be used for ``swap
8311 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8312 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8313 It is possible to specify a swap file in a file system on a mapped
8314 device, provided that the necessary device mapping and file system are
8315 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8317 @item @code{users} (default: @code{%base-user-accounts})
8318 @itemx @code{groups} (default: @var{%base-groups})
8319 List of user accounts and groups. @xref{User Accounts}.
8321 @item @code{skeletons} (default: @code{(default-skeletons)})
8322 A list target file name/file-like object tuples (@pxref{G-Expressions,
8323 file-like objects}). These are the skeleton files that will be added to
8324 the home directory of newly-created user accounts.
8326 For instance, a valid value may look like this:
8329 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8330 (".guile" ,(plain-file "guile"
8331 "(use-modules (ice-9 readline))
8332 (activate-readline)")))
8335 @item @code{issue} (default: @var{%default-issue})
8336 A string denoting the contents of the @file{/etc/issue} file, which is
8337 displayed when users log in on a text console.
8339 @item @code{packages} (default: @var{%base-packages})
8340 The set of packages installed in the global profile, which is accessible
8341 at @file{/run/current-system/profile}.
8343 The default set includes core utilities and it is good practice to
8344 install non-core utilities in user profiles (@pxref{Invoking guix
8347 @item @code{timezone}
8348 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8350 You can run the @command{tzselect} command to find out which timezone
8351 string corresponds to your region. Choosing an invalid timezone name
8352 causes @command{guix system} to fail.
8354 @item @code{locale} (default: @code{"en_US.utf8"})
8355 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8356 Library Reference Manual}). @xref{Locales}, for more information.
8358 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8359 The list of locale definitions to be compiled and that may be used at
8360 run time. @xref{Locales}.
8362 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8363 The list of GNU@tie{}libc packages whose locale data and tools are used
8364 to build the locale definitions. @xref{Locales}, for compatibility
8365 considerations that justify this option.
8367 @item @code{name-service-switch} (default: @var{%default-nss})
8368 Configuration of the libc name service switch (NSS)---a
8369 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8372 @item @code{services} (default: @var{%base-services})
8373 A list of service objects denoting system services. @xref{Services}.
8375 @item @code{pam-services} (default: @code{(base-pam-services)})
8377 @cindex pluggable authentication modules
8378 Linux @dfn{pluggable authentication module} (PAM) services.
8379 @c FIXME: Add xref to PAM services section.
8381 @item @code{setuid-programs} (default: @var{%setuid-programs})
8382 List of string-valued G-expressions denoting setuid programs.
8383 @xref{Setuid Programs}.
8385 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8386 @cindex sudoers file
8387 The contents of the @file{/etc/sudoers} file as a file-like object
8388 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8390 This file specifies which users can use the @command{sudo} command, what
8391 they are allowed to do, and what privileges they may gain. The default
8392 is that only @code{root} and members of the @code{wheel} group may use
8399 @subsection File Systems
8401 The list of file systems to be mounted is specified in the
8402 @code{file-systems} field of the operating system declaration
8403 (@pxref{Using the Configuration System}). Each file system is declared
8404 using the @code{file-system} form, like this:
8408 (mount-point "/home")
8409 (device "/dev/sda3")
8413 As usual, some of the fields are mandatory---those shown in the example
8414 above---while others can be omitted. These are described below.
8416 @deftp {Data Type} file-system
8417 Objects of this type represent file systems to be mounted. They
8418 contain the following members:
8422 This is a string specifying the type of the file system---e.g.,
8425 @item @code{mount-point}
8426 This designates the place where the file system is to be mounted.
8429 This names the ``source'' of the file system. By default it is the name
8430 of a node under @file{/dev}, but its meaning depends on the @code{title}
8431 field described below.
8433 @item @code{title} (default: @code{'device})
8434 This is a symbol that specifies how the @code{device} field is to be
8437 When it is the symbol @code{device}, then the @code{device} field is
8438 interpreted as a file name; when it is @code{label}, then @code{device}
8439 is interpreted as a partition label name; when it is @code{uuid},
8440 @code{device} is interpreted as a partition unique identifier (UUID).
8442 UUIDs may be converted from their string representation (as shown by the
8443 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8444 @code{uuid} form expects 16-byte UUIDs as defined in
8445 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8446 form of UUID used by the ext2 family of file systems and others, but it
8447 is different from ``UUIDs'' found in FAT file systems, for instance.},
8452 (mount-point "/home")
8455 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8458 The @code{label} and @code{uuid} options offer a way to refer to disk
8459 partitions without having to hard-code their actual device
8460 name@footnote{Note that, while it is tempting to use
8461 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8462 result, this is not recommended: These special device nodes are created
8463 by the udev daemon and may be unavailable at the time the device is
8466 However, when the source of a file system is a mapped device (@pxref{Mapped
8467 Devices}), its @code{device} field @emph{must} refer to the mapped
8468 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8469 @code{title} must be set to @code{'device}. This is required so that
8470 the system knows that mounting the file system depends on having the
8471 corresponding device mapping established.
8473 @item @code{flags} (default: @code{'()})
8474 This is a list of symbols denoting mount flags. Recognized flags
8475 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8476 access to special files), @code{no-suid} (ignore setuid and setgid
8477 bits), and @code{no-exec} (disallow program execution.)
8479 @item @code{options} (default: @code{#f})
8480 This is either @code{#f}, or a string denoting mount options.
8482 @item @code{mount?} (default: @code{#t})
8483 This value indicates whether to automatically mount the file system when
8484 the system is brought up. When set to @code{#f}, the file system gets
8485 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8486 is not automatically mounted.
8488 @item @code{needed-for-boot?} (default: @code{#f})
8489 This Boolean value indicates whether the file system is needed when
8490 booting. If that is true, then the file system is mounted when the
8491 initial RAM disk (initrd) is loaded. This is always the case, for
8492 instance, for the root file system.
8494 @item @code{check?} (default: @code{#t})
8495 This Boolean indicates whether the file system needs to be checked for
8496 errors before being mounted.
8498 @item @code{create-mount-point?} (default: @code{#f})
8499 When true, the mount point is created if it does not exist yet.
8501 @item @code{dependencies} (default: @code{'()})
8502 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8503 representing file systems that must be mounted or mapped devices that
8504 must be opened before (and unmounted or closed after) this one.
8506 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8507 a dependency of @file{/sys/fs/cgroup/cpu} and
8508 @file{/sys/fs/cgroup/memory}.
8510 Another example is a file system that depends on a mapped device, for
8511 example for an encrypted partition (@pxref{Mapped Devices}).
8515 The @code{(gnu system file-systems)} exports the following useful
8518 @defvr {Scheme Variable} %base-file-systems
8519 These are essential file systems that are required on normal systems,
8520 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8521 below.) Operating system declarations should always contain at least
8525 @defvr {Scheme Variable} %pseudo-terminal-file-system
8526 This is the file system to be mounted as @file{/dev/pts}. It supports
8527 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8528 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8529 Manual}). Pseudo-terminals are used by terminal emulators such as
8533 @defvr {Scheme Variable} %shared-memory-file-system
8534 This file system is mounted as @file{/dev/shm} and is used to support
8535 memory sharing across processes (@pxref{Memory-mapped I/O,
8536 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8539 @defvr {Scheme Variable} %immutable-store
8540 This file system performs a read-only ``bind mount'' of
8541 @file{/gnu/store}, making it read-only for all the users including
8542 @code{root}. This prevents against accidental modification by software
8543 running as @code{root} or by system administrators.
8545 The daemon itself is still able to write to the store: it remounts it
8546 read-write in its own ``name space.''
8549 @defvr {Scheme Variable} %binary-format-file-system
8550 The @code{binfmt_misc} file system, which allows handling of arbitrary
8551 executable file types to be delegated to user space. This requires the
8552 @code{binfmt.ko} kernel module to be loaded.
8555 @defvr {Scheme Variable} %fuse-control-file-system
8556 The @code{fusectl} file system, which allows unprivileged users to mount
8557 and unmount user-space FUSE file systems. This requires the
8558 @code{fuse.ko} kernel module to be loaded.
8561 @node Mapped Devices
8562 @subsection Mapped Devices
8564 @cindex device mapping
8565 @cindex mapped devices
8566 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8567 such as a hard disk partition, can be @dfn{mapped} into another device,
8568 usually in @code{/dev/mapper/},
8569 with additional processing over the data that flows through
8570 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8571 concept of a ``mapped device'' and that of a file system: both boil down
8572 to @emph{translating} input/output operations made on a file to
8573 operations on its backing store. Thus, the Hurd implements mapped
8574 devices, like file systems, using the generic @dfn{translator} mechanism
8575 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8576 typical example is encryption device mapping: all writes to the mapped
8577 device are encrypted, and all reads are deciphered, transparently.
8578 Guix extends this notion by considering any device or set of devices that
8579 are @dfn{transformed} in some way to create a new device; for instance,
8580 RAID devices are obtained by @dfn{assembling} several other devices, such
8581 as hard disks or partitions, into a new one that behaves as one partition.
8582 Other examples, not yet implemented, are LVM logical volumes.
8584 Mapped devices are declared using the @code{mapped-device} form,
8585 defined as follows; for examples, see below.
8587 @deftp {Data Type} mapped-device
8588 Objects of this type represent device mappings that will be made when
8589 the system boots up.
8593 This is either a string specifying the name of the block device to be mapped,
8594 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8595 need to be assembled for creating a new one.
8598 This string specifies the name of the resulting mapped device. For
8599 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8600 specifying @code{"my-partition"} leads to the creation of
8601 the @code{"/dev/mapper/my-partition"} device.
8602 For RAID devices of type @code{raid-device-mapping}, the full device name
8603 such as @code{"/dev/md0"} needs to be given.
8606 This must be a @code{mapped-device-kind} object, which specifies how
8607 @var{source} is mapped to @var{target}.
8611 @defvr {Scheme Variable} luks-device-mapping
8612 This defines LUKS block device encryption using the @command{cryptsetup}
8613 command from the package with the same name. It relies on the
8614 @code{dm-crypt} Linux kernel module.
8617 @defvr {Scheme Variable} raid-device-mapping
8618 This defines a RAID device, which is assembled using the @code{mdadm}
8619 command from the package with the same name. It requires a Linux kernel
8620 module for the appropriate RAID level to be loaded, such as @code{raid456}
8621 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8624 @cindex disk encryption
8626 The following example specifies a mapping from @file{/dev/sda3} to
8627 @file{/dev/mapper/home} using LUKS---the
8628 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8629 standard mechanism for disk encryption.
8630 The @file{/dev/mapper/home}
8631 device can then be used as the @code{device} of a @code{file-system}
8632 declaration (@pxref{File Systems}).
8636 (source "/dev/sda3")
8638 (type luks-device-mapping))
8641 Alternatively, to become independent of device numbering, one may obtain
8642 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8646 cryptsetup luksUUID /dev/sda3
8649 and use it as follows:
8653 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8655 (type luks-device-mapping))
8658 @cindex swap encryption
8659 It is also desirable to encrypt swap space, since swap space may contain
8660 sensitive data. One way to accomplish that is to use a swap file in a
8661 file system on a device mapped via LUKS encryption. In this way, the
8662 swap file is encrypted because the entire device is encrypted.
8663 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8665 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8666 may be declared as follows:
8670 (source (list "/dev/sda1" "/dev/sdb1"))
8672 (type raid-device-mapping))
8675 The @file{/dev/md0} device can then be used as the @code{device} of a
8676 @code{file-system} declaration (@pxref{File Systems}).
8677 Note that the RAID level need not be given; it is chosen during the
8678 initial creation and formatting of the RAID device and is determined
8679 automatically later.
8683 @subsection User Accounts
8687 @cindex user accounts
8688 User accounts and groups are entirely managed through the
8689 @code{operating-system} declaration. They are specified with the
8690 @code{user-account} and @code{user-group} forms:
8696 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8698 "video" ;video devices such as webcams
8699 "cdrom")) ;the good ol' CD-ROM
8700 (comment "Bob's sister")
8701 (home-directory "/home/alice"))
8704 When booting or upon completion of @command{guix system reconfigure},
8705 the system ensures that only the user accounts and groups specified in
8706 the @code{operating-system} declaration exist, and with the specified
8707 properties. Thus, account or group creations or modifications made by
8708 directly invoking commands such as @command{useradd} are lost upon
8709 reconfiguration or reboot. This ensures that the system remains exactly
8712 @deftp {Data Type} user-account
8713 Objects of this type represent user accounts. The following members may
8718 The name of the user account.
8722 This is the name (a string) or identifier (a number) of the user group
8723 this account belongs to.
8725 @item @code{supplementary-groups} (default: @code{'()})
8726 Optionally, this can be defined as a list of group names that this
8729 @item @code{uid} (default: @code{#f})
8730 This is the user ID for this account (a number), or @code{#f}. In the
8731 latter case, a number is automatically chosen by the system when the
8734 @item @code{comment} (default: @code{""})
8735 A comment about the account, such as the account owner's full name.
8737 @item @code{home-directory}
8738 This is the name of the home directory for the account.
8740 @item @code{create-home-directory?} (default: @code{#t})
8741 Indicates whether the home directory of this account should be created
8742 if it does not exist yet.
8744 @item @code{shell} (default: Bash)
8745 This is a G-expression denoting the file name of a program to be used as
8746 the shell (@pxref{G-Expressions}).
8748 @item @code{system?} (default: @code{#f})
8749 This Boolean value indicates whether the account is a ``system''
8750 account. System accounts are sometimes treated specially; for instance,
8751 graphical login managers do not list them.
8753 @anchor{user-account-password}
8754 @item @code{password} (default: @code{#f})
8755 You would normally leave this field to @code{#f}, initialize user
8756 passwords as @code{root} with the @command{passwd} command, and then let
8757 users change it with @command{passwd}. Passwords set with
8758 @command{passwd} are of course preserved across reboot and
8761 If you @emph{do} want to have a preset password for an account, then
8762 this field must contain the encrypted password, as a string.
8763 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8764 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8765 Manual}, for information on Guile's @code{crypt} procedure.
8771 User group declarations are even simpler:
8774 (user-group (name "students"))
8777 @deftp {Data Type} user-group
8778 This type is for, well, user groups. There are just a few fields:
8782 The name of the group.
8784 @item @code{id} (default: @code{#f})
8785 The group identifier (a number). If @code{#f}, a new number is
8786 automatically allocated when the group is created.
8788 @item @code{system?} (default: @code{#f})
8789 This Boolean value indicates whether the group is a ``system'' group.
8790 System groups have low numerical IDs.
8792 @item @code{password} (default: @code{#f})
8793 What, user groups can have a password? Well, apparently yes. Unless
8794 @code{#f}, this field specifies the password of the group.
8799 For convenience, a variable lists all the basic user groups one may
8802 @defvr {Scheme Variable} %base-groups
8803 This is the list of basic user groups that users and/or packages expect
8804 to be present on the system. This includes groups such as ``root'',
8805 ``wheel'', and ``users'', as well as groups used to control access to
8806 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8809 @defvr {Scheme Variable} %base-user-accounts
8810 This is the list of basic system accounts that programs may expect to
8811 find on a GNU/Linux system, such as the ``nobody'' account.
8813 Note that the ``root'' account is not included here. It is a
8814 special-case and is automatically added whether or not it is specified.
8821 A @dfn{locale} defines cultural conventions for a particular language
8822 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8823 Reference Manual}). Each locale has a name that typically has the form
8824 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8825 @code{fr_LU.utf8} designates the locale for the French language, with
8826 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8828 @cindex locale definition
8829 Usually, you will want to specify the default locale for the machine
8830 using the @code{locale} field of the @code{operating-system} declaration
8831 (@pxref{operating-system Reference, @code{locale}}).
8833 The selected locale is automatically added to the @dfn{locale
8834 definitions} known to the system if needed, with its codeset inferred
8835 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8836 @code{UTF-8} codeset. Additional locale definitions can be specified in
8837 the @code{locale-definitions} slot of @code{operating-system}---this is
8838 useful, for instance, if the codeset could not be inferred from the
8839 locale name. The default set of locale definitions includes some widely
8840 used locales, but not all the available locales, in order to save space.
8842 For instance, to add the North Frisian locale for Germany, the value of
8846 (cons (locale-definition
8847 (name "fy_DE.utf8") (source "fy_DE"))
8848 %default-locale-definitions)
8851 Likewise, to save space, one might want @code{locale-definitions} to
8852 list only the locales that are actually used, as in:
8855 (list (locale-definition
8856 (name "ja_JP.eucjp") (source "ja_JP")
8857 (charset "EUC-JP")))
8861 The compiled locale definitions are available at
8862 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8863 version, which is the default location where the GNU@tie{}libc provided
8864 by Guix looks for locale data. This can be overridden using the
8865 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8866 @code{LOCPATH} and locale packages}).
8868 The @code{locale-definition} form is provided by the @code{(gnu system
8869 locale)} module. Details are given below.
8871 @deftp {Data Type} locale-definition
8872 This is the data type of a locale definition.
8877 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8878 Reference Manual}, for more information on locale names.
8881 The name of the source for that locale. This is typically the
8882 @code{@var{language}_@var{territory}} part of the locale name.
8884 @item @code{charset} (default: @code{"UTF-8"})
8885 The ``character set'' or ``code set'' for that locale,
8886 @uref{http://www.iana.org/assignments/character-sets, as defined by
8892 @defvr {Scheme Variable} %default-locale-definitions
8893 A list of commonly used UTF-8 locales, used as the default
8894 value of the @code{locale-definitions} field of @code{operating-system}
8898 @cindex normalized codeset in locale names
8899 These locale definitions use the @dfn{normalized codeset} for the part
8900 that follows the dot in the name (@pxref{Using gettextized software,
8901 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8902 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8906 @subsubsection Locale Data Compatibility Considerations
8908 @cindex incompatibility, of locale data
8909 @code{operating-system} declarations provide a @code{locale-libcs} field
8910 to specify the GNU@tie{}libc packages that are used to compile locale
8911 declarations (@pxref{operating-system Reference}). ``Why would I
8912 care?'', you may ask. Well, it turns out that the binary format of
8913 locale data is occasionally incompatible from one libc version to
8916 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8917 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8918 For instance, a program linked against libc version 2.21 is unable to
8919 read locale data produced with libc 2.22; worse, that program
8920 @emph{aborts} instead of simply ignoring the incompatible locale
8921 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8922 the incompatible locale data, which is already an improvement.}.
8923 Similarly, a program linked against libc 2.22 can read most, but not
8924 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8925 data is incompatible); thus calls to @code{setlocale} may fail, but
8926 programs will not abort.
8928 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8929 choose whether and when to upgrade software in their profiles, and might
8930 be using a libc version different from the one the system administrator
8931 used to build the system-wide locale data.
8933 Fortunately, unprivileged users can also install their own locale data
8934 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8935 @code{GUIX_LOCPATH} and locale packages}).
8937 Still, it is best if the system-wide locale data at
8938 @file{/run/current-system/locale} is built for all the libc versions
8939 actually in use on the system, so that all the programs can access
8940 it---this is especially crucial on a multi-user system. To do that, the
8941 administrator can specify several libc packages in the
8942 @code{locale-libcs} field of @code{operating-system}:
8945 (use-package-modules base)
8949 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8952 This example would lead to a system containing locale definitions for
8953 both libc 2.21 and the current version of libc in
8954 @file{/run/current-system/locale}.
8958 @subsection Services
8960 @cindex system services
8961 An important part of preparing an @code{operating-system} declaration is
8962 listing @dfn{system services} and their configuration (@pxref{Using the
8963 Configuration System}). System services are typically daemons launched
8964 when the system boots, or other actions needed at that time---e.g.,
8965 configuring network access.
8967 GuixSD has a broad definition of ``service'' (@pxref{Service
8968 Composition}), but many services are managed by the GNU@tie{}Shepherd
8969 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8970 command allows you to list the available services, show their status,
8971 start and stop them, or do other specific operations (@pxref{Jump
8972 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8978 The above command, run as @code{root}, lists the currently defined
8979 services. The @command{herd doc} command shows a synopsis of the given
8984 Run libc's name service cache daemon (nscd).
8987 The @command{start}, @command{stop}, and @command{restart} sub-commands
8988 have the effect you would expect. For instance, the commands below stop
8989 the nscd service and restart the Xorg display server:
8993 Service nscd has been stopped.
8994 # herd restart xorg-server
8995 Service xorg-server has been stopped.
8996 Service xorg-server has been started.
8999 The following sections document the available services, starting with
9000 the core services, that may be used in an @code{operating-system}
9004 * Base Services:: Essential system services.
9005 * Scheduled Job Execution:: The mcron service.
9006 * Log Rotation:: The rottlog service.
9007 * Networking Services:: Network setup, SSH daemon, etc.
9008 * X Window:: Graphical display.
9009 * Printing Services:: Local and remote printer support.
9010 * Desktop Services:: D-Bus and desktop services.
9011 * Database Services:: SQL databases.
9012 * Mail Services:: IMAP, POP3, SMTP, and all that.
9013 * Messaging Services:: Messaging services.
9014 * Kerberos Services:: Kerberos services.
9015 * Web Services:: Web servers.
9016 * DNS Services:: DNS daemons.
9017 * VPN Services:: VPN daemons.
9018 * Network File System:: NFS related services.
9019 * Continuous Integration:: The Cuirass service.
9020 * Power management Services:: The TLP tool.
9021 * Miscellaneous Services:: Other services.
9025 @subsubsection Base Services
9027 The @code{(gnu services base)} module provides definitions for the basic
9028 services that one expects from the system. The services exported by
9029 this module are listed below.
9031 @defvr {Scheme Variable} %base-services
9032 This variable contains a list of basic services (@pxref{Service Types
9033 and Services}, for more information on service objects) one would
9034 expect from the system: a login service (mingetty) on each tty, syslogd,
9035 the libc name service cache daemon (nscd), the udev device manager, and
9038 This is the default value of the @code{services} field of
9039 @code{operating-system} declarations. Usually, when customizing a
9040 system, you will want to append services to @var{%base-services}, like
9044 (cons* (avahi-service) (lsh-service) %base-services)
9048 @defvr {Scheme Variable} special-files-service-type
9049 This is the service that sets up ``special files'' such as
9050 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
9052 The value associated with @code{special-files-service-type} services
9053 must be a list of tuples where the first element is the ``special file''
9054 and the second element is its target. By default it is:
9056 @cindex @file{/bin/sh}
9057 @cindex @file{sh}, in @file{/bin}
9059 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
9062 @cindex @file{/usr/bin/env}
9063 @cindex @file{env}, in @file{/usr/bin}
9064 If you want to add, say, @code{/usr/bin/env} to your system, you can
9068 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
9069 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
9072 Since this is part of @code{%base-services}, you can use
9073 @code{modify-services} to customize the set of special files
9074 (@pxref{Service Reference, @code{modify-services}}). But the simple way
9075 to add a special file is @i{via} the @code{extra-special-file} procedure
9079 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
9080 Use @var{target} as the ``special file'' @var{file}.
9082 For example, adding the following lines to the @code{services} field of
9083 your operating system declaration leads to a @file{/usr/bin/env}
9087 (extra-special-file "/usr/bin/env"
9088 (file-append coreutils "/bin/env"))
9092 @deffn {Scheme Procedure} host-name-service @var{name}
9093 Return a service that sets the host name to @var{name}.
9096 @deffn {Scheme Procedure} login-service @var{config}
9097 Return a service to run login according to @var{config}, a
9098 @code{<login-configuration>} object, which specifies the message of the day,
9102 @deftp {Data Type} login-configuration
9103 This is the data type representing the configuration of login.
9108 @cindex message of the day
9109 A file-like object containing the ``message of the day''.
9111 @item @code{allow-empty-passwords?} (default: @code{#t})
9112 Allow empty passwords by default so that first-time users can log in when
9113 the 'root' account has just been created.
9118 @deffn {Scheme Procedure} mingetty-service @var{config}
9119 Return a service to run mingetty according to @var{config}, a
9120 @code{<mingetty-configuration>} object, which specifies the tty to run, among
9124 @deftp {Data Type} mingetty-configuration
9125 This is the data type representing the configuration of Mingetty, which
9126 provides the default implementation of virtual console log-in.
9131 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
9133 @item @code{auto-login} (default: @code{#f})
9134 When true, this field must be a string denoting the user name under
9135 which the system automatically logs in. When it is @code{#f}, a
9136 user name and password must be entered to log in.
9138 @item @code{login-program} (default: @code{#f})
9139 This must be either @code{#f}, in which case the default log-in program
9140 is used (@command{login} from the Shadow tool suite), or a gexp denoting
9141 the name of the log-in program.
9143 @item @code{login-pause?} (default: @code{#f})
9144 When set to @code{#t} in conjunction with @var{auto-login}, the user
9145 will have to press a key before the log-in shell is launched.
9147 @item @code{mingetty} (default: @var{mingetty})
9148 The Mingetty package to use.
9153 @deffn {Scheme Procedure} agetty-service @var{config}
9154 Return a service to run agetty according to @var{config}, an
9155 @code{<agetty-configuration>} object, which specifies the tty to run,
9159 @deftp {Data Type} agetty-configuration
9160 This is the data type representing the configuration of agetty, which
9161 implements virtual and serial console log-in. See the @code{agetty(8)}
9162 man page for more information.
9167 The name of the console this agetty runs on, as a string---e.g.,
9168 @code{"ttyS0"}. This argument is mandatory.
9170 @item @code{baud-rate} (default: @code{#f})
9171 A string containing a comma-separated list of one or more baud rates, in
9174 @item @code{term} (default: @code{#f})
9175 A string containing the value used for the @code{TERM} environment
9178 @item @code{eight-bits?} (default: @code{#f})
9179 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
9182 @item @code{auto-login} (default: @code{#f})
9183 When passed a login name, as a string, the specified user will be logged
9184 in automatically without prompting for their login name or password.
9186 @item @code{no-reset?} (default: @code{#f})
9187 When @code{#t}, don't reset terminal cflags (control modes).
9189 @item @code{host} (default: @code{#f})
9190 This accepts a string containing the "login_host", which will be written
9191 into the @file{/var/run/utmpx} file.
9193 @item @code{remote?} (default: @code{#f})
9194 When set to @code{#t} in conjunction with @var{host}, this will add an
9195 @code{-r} fakehost option to the command line of the login program
9196 specified in @var{login-program}.
9198 @item @code{flow-control?} (default: @code{#f})
9199 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
9201 @item @code{no-issue?} (default: @code{#f})
9202 When set to @code{#t}, the contents of the @file{/etc/issue} file will
9203 not be displayed before presenting the login prompt.
9205 @item @code{init-string} (default: @code{#f})
9206 This accepts a string that will be sent to the tty or modem before
9207 sending anything else. It can be used to initialize a modem.
9209 @item @code{no-clear?} (default: @code{#f})
9210 When set to @code{#t}, agetty will not clear the screen before showing
9213 @item @code{login-program} (default: (file-append shadow "/bin/login"))
9214 This must be either a gexp denoting the name of a log-in program, or
9215 unset, in which case the default value is the @command{login} from the
9218 @item @code{local-line} (default: @code{#f})
9219 Control the CLOCAL line flag. This accepts one of three symbols as
9220 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
9221 the default value chosen by agetty is @code{'auto}.
9223 @item @code{extract-baud?} (default: @code{#f})
9224 When set to @code{#t}, instruct agetty to try to extract the baud rate
9225 from the status messages produced by certain types of modems.
9227 @item @code{skip-login?} (default: @code{#f})
9228 When set to @code{#t}, do not prompt the user for a login name. This
9229 can be used with @var{login-program} field to use non-standard login
9232 @item @code{no-newline?} (default: @code{#f})
9233 When set to @code{#t}, do not print a newline before printing the
9234 @file{/etc/issue} file.
9236 @c Is this dangerous only when used with login-program, or always?
9237 @item @code{login-options} (default: @code{#f})
9238 This option accepts a string containing options that are passed to the
9239 login program. When used with the @var{login-program}, be aware that a
9240 malicious user could try to enter a login name containing embedded
9241 options that could be parsed by the login program.
9243 @item @code{login-pause} (default: @code{#f})
9244 When set to @code{#t}, wait for any key before showing the login prompt.
9245 This can be used in conjunction with @var{auto-login} to save memory by
9246 lazily spawning shells.
9248 @item @code{chroot} (default: @code{#f})
9249 Change root to the specified directory. This option accepts a directory
9252 @item @code{hangup?} (default: @code{#f})
9253 Use the Linux system call @code{vhangup} to do a virtual hangup of the
9256 @item @code{keep-baud?} (default: @code{#f})
9257 When set to @code{#t}, try to keep the existing baud rate. The baud
9258 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
9261 @item @code{timeout} (default: @code{#f})
9262 When set to an integer value, terminate if no user name could be read
9263 within @var{timeout} seconds.
9265 @item @code{detect-case?} (default: @code{#f})
9266 When set to @code{#t}, turn on support for detecting an uppercase-only
9267 terminal. This setting will detect a login name containing only
9268 uppercase letters as indicating an uppercase-only terminal and turn on
9269 some upper-to-lower case conversions. Note that this will not support
9272 @item @code{wait-cr?} (default: @code{#f})
9273 When set to @code{#t}, wait for the user or modem to send a
9274 carriage-return or linefeed character before displaying
9275 @file{/etc/issue} or login prompt. This is typically used with the
9276 @var{init-string} option.
9278 @item @code{no-hints?} (default: @code{#f})
9279 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9282 @item @code{no-hostname?} (default: @code{#f})
9283 By default, the hostname is printed. When this option is set to
9284 @code{#t}, no hostname will be shown at all.
9286 @item @code{long-hostname?} (default: @code{#f})
9287 By default, the hostname is only printed until the first dot. When this
9288 option is set to @code{#t}, the fully qualified hostname by
9289 @code{gethostname} or @code{getaddrinfo} is shown.
9291 @item @code{erase-characters} (default: @code{#f})
9292 This option accepts a string of additional characters that should be
9293 interpreted as backspace when the user types their login name.
9295 @item @code{kill-characters} (default: @code{#f})
9296 This option accepts a string that should be interpreted to mean "ignore
9297 all previous characters" (also called a "kill" character) when the types
9300 @item @code{chdir} (default: @code{#f})
9301 This option accepts, as a string, a directory path that will be changed
9304 @item @code{delay} (default: @code{#f})
9305 This options accepts, as an integer, the number of seconds to sleep
9306 before opening the tty and displaying the login prompt.
9308 @item @code{nice} (default: @code{#f})
9309 This option accepts, as an integer, the nice value with which to run the
9310 @command{login} program.
9312 @item @code{extra-options} (default: @code{'()})
9313 This option provides an "escape hatch" for the user to provide arbitrary
9314 command-line arguments to @command{agetty} as a list of strings.
9319 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9320 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9321 according to @var{config}, a @code{<kmscon-configuration>} object, which
9322 specifies the tty to run, among other things.
9325 @deftp {Data Type} kmscon-configuration
9326 This is the data type representing the configuration of Kmscon, which
9327 implements virtual console log-in.
9331 @item @code{virtual-terminal}
9332 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9334 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9335 A gexp denoting the name of the log-in program. The default log-in program is
9336 @command{login} from the Shadow tool suite.
9338 @item @code{login-arguments} (default: @code{'("-p")})
9339 A list of arguments to pass to @command{login}.
9341 @item @code{hardware-acceleration?} (default: #f)
9342 Whether to use hardware acceleration.
9344 @item @code{kmscon} (default: @var{kmscon})
9345 The Kmscon package to use.
9350 @cindex name service cache daemon
9352 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9353 [#:name-services '()]
9354 Return a service that runs the libc name service cache daemon (nscd) with the
9355 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9356 Service Switch}, for an example.
9359 @defvr {Scheme Variable} %nscd-default-configuration
9360 This is the default @code{<nscd-configuration>} value (see below) used
9361 by @code{nscd-service}. It uses the caches defined by
9362 @var{%nscd-default-caches}; see below.
9365 @deftp {Data Type} nscd-configuration
9366 This is the data type representing the name service cache daemon (nscd)
9371 @item @code{name-services} (default: @code{'()})
9372 List of packages denoting @dfn{name services} that must be visible to
9373 the nscd---e.g., @code{(list @var{nss-mdns})}.
9375 @item @code{glibc} (default: @var{glibc})
9376 Package object denoting the GNU C Library providing the @command{nscd}
9379 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9380 Name of the nscd log file. This is where debugging output goes when
9381 @code{debug-level} is strictly positive.
9383 @item @code{debug-level} (default: @code{0})
9384 Integer denoting the debugging levels. Higher numbers mean that more
9385 debugging output is logged.
9387 @item @code{caches} (default: @var{%nscd-default-caches})
9388 List of @code{<nscd-cache>} objects denoting things to be cached; see
9394 @deftp {Data Type} nscd-cache
9395 Data type representing a cache database of nscd and its parameters.
9399 @item @code{database}
9400 This is a symbol representing the name of the database to be cached.
9401 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9402 @code{services}, which designate the corresponding NSS database
9403 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9405 @item @code{positive-time-to-live}
9406 @itemx @code{negative-time-to-live} (default: @code{20})
9407 A number representing the number of seconds during which a positive or
9408 negative lookup result remains in cache.
9410 @item @code{check-files?} (default: @code{#t})
9411 Whether to check for updates of the files corresponding to
9414 For instance, when @var{database} is @code{hosts}, setting this flag
9415 instructs nscd to check for updates in @file{/etc/hosts} and to take
9418 @item @code{persistent?} (default: @code{#t})
9419 Whether the cache should be stored persistently on disk.
9421 @item @code{shared?} (default: @code{#t})
9422 Whether the cache should be shared among users.
9424 @item @code{max-database-size} (default: 32@tie{}MiB)
9425 Maximum size in bytes of the database cache.
9427 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9428 @c settings, so leave them out.
9433 @defvr {Scheme Variable} %nscd-default-caches
9434 List of @code{<nscd-cache>} objects used by default by
9435 @code{nscd-configuration} (see above).
9437 It enables persistent and aggressive caching of service and host name
9438 lookups. The latter provides better host name lookup performance,
9439 resilience in the face of unreliable name servers, and also better
9440 privacy---often the result of host name lookups is in local cache, so
9441 external name servers do not even need to be queried.
9444 @anchor{syslog-configuration-type}
9447 @deftp {Data Type} syslog-configuration
9448 This data type represents the configuration of the syslog daemon.
9451 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9452 The syslog daemon to use.
9454 @item @code{config-file} (default: @code{%default-syslog.conf})
9455 The syslog configuration file to use.
9460 @anchor{syslog-service}
9462 @deffn {Scheme Procedure} syslog-service @var{config}
9463 Return a service that runs a syslog daemon according to @var{config}.
9465 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9466 information on the configuration file syntax.
9469 @anchor{guix-configuration-type}
9470 @deftp {Data Type} guix-configuration
9471 This data type represents the configuration of the Guix build daemon.
9472 @xref{Invoking guix-daemon}, for more information.
9475 @item @code{guix} (default: @var{guix})
9476 The Guix package to use.
9478 @item @code{build-group} (default: @code{"guixbuild"})
9479 Name of the group for build user accounts.
9481 @item @code{build-accounts} (default: @code{10})
9482 Number of build user accounts to create.
9484 @item @code{authorize-key?} (default: @code{#t})
9485 @cindex substitutes, authorization thereof
9486 Whether to authorize the substitute keys listed in
9487 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9488 (@pxref{Substitutes}).
9490 @vindex %default-authorized-guix-keys
9491 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9492 The list of authorized key files for archive imports, as a list of
9493 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9494 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9496 @item @code{use-substitutes?} (default: @code{#t})
9497 Whether to use substitutes.
9499 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9500 The list of URLs where to look for substitutes by default.
9502 @item @code{max-silent-time} (default: @code{0})
9503 @itemx @code{timeout} (default: @code{0})
9504 The number of seconds of silence and the number of seconds of activity,
9505 respectively, after which a build process times out. A value of zero
9506 disables the timeout.
9508 @item @code{extra-options} (default: @code{'()})
9509 List of extra command-line options for @command{guix-daemon}.
9511 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9512 File where @command{guix-daemon}'s standard output and standard error
9515 @item @code{lsof} (default: @var{lsof})
9516 The lsof package to use.
9518 @item @code{http-proxy} (default: @code{#f})
9519 The HTTP proxy used for downloading fixed-output derivations and
9522 @item @code{tmpdir} (default: @code{#f})
9523 A directory path where the @command{guix-daemon} will perform builds.
9528 @deffn {Scheme Procedure} guix-service @var{config}
9529 Return a service that runs the Guix build daemon according to
9533 @deffn {Scheme Procedure} udev-service [#:udev udev]
9534 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9537 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9538 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9542 @defvr {Scheme Variable} %random-seed-file
9543 This is the name of the file where some random bytes are saved by
9544 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9545 It defaults to @file{/var/lib/random-seed}.
9550 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9551 @cindex keyboard layout
9552 Return a service to load console keymaps from @var{files} using
9553 @command{loadkeys} command. Most likely, you want to load some default
9554 keymap, which can be done like this:
9557 (console-keymap-service "dvorak")
9560 Or, for example, for a Swedish keyboard, you may need to combine
9561 the following keymaps:
9563 (console-keymap-service "se-lat6" "se-fi-lat6")
9566 Also you can specify a full file name (or file names) of your keymap(s).
9567 See @code{man loadkeys} for details.
9573 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9575 Run @var{gpm}, the general-purpose mouse daemon, with the given
9576 command-line @var{options}. GPM allows users to use the mouse in the console,
9577 notably to select, copy, and paste text. The default value of @var{options}
9578 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9580 This service is not part of @var{%base-services}.
9583 @anchor{guix-publish-service-type}
9584 @deffn {Scheme Variable} guix-publish-service-type
9585 This is the service type for @command{guix publish} (@pxref{Invoking
9586 guix publish}). Its value must be a @code{guix-configuration}
9587 object, as described below.
9589 This assumes that @file{/etc/guix} already contains a signing key pair as
9590 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9591 archive}). If that is not the case, the service will fail to start.
9594 @deftp {Data Type} guix-publish-configuration
9595 Data type representing the configuration of the @code{guix publish}
9599 @item @code{guix} (default: @code{guix})
9600 The Guix package to use.
9602 @item @code{port} (default: @code{80})
9603 The TCP port to listen for connections.
9605 @item @code{host} (default: @code{"localhost"})
9606 The host (and thus, network interface) to listen to. Use
9607 @code{"0.0.0.0"} to listen on all the network interfaces.
9609 @item @code{compression-level} (default: @code{3})
9610 The gzip compression level at which substitutes are compressed. Use
9611 @code{0} to disable compression altogether, and @code{9} to get the best
9612 compression ratio at the expense of increased CPU usage.
9614 @item @code{nar-path} (default: @code{"nar"})
9615 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9616 publish, @code{--nar-path}}, for details.
9618 @item @code{cache} (default: @code{#f})
9619 When it is @code{#f}, disable caching and instead generate archives on
9620 demand. Otherwise, this should be the name of a directory---e.g.,
9621 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9622 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9623 @option{--cache}}, for more information on the tradeoffs involved.
9625 @item @code{workers} (default: @code{#f})
9626 When it is an integer, this is the number of worker threads used for
9627 caching; when @code{#f}, the number of processors is used.
9628 @xref{Invoking guix publish, @option{--workers}}, for more information.
9630 @item @code{ttl} (default: @code{#f})
9631 When it is an integer, this denotes the @dfn{time-to-live} of the
9632 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9637 @anchor{rngd-service}
9638 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9639 [#:device "/dev/hwrng"]
9640 Return a service that runs the @command{rngd} program from @var{rng-tools}
9641 to add @var{device} to the kernel's entropy pool. The service will fail if
9642 @var{device} does not exist.
9645 @anchor{pam-limits-service}
9646 @cindex session limits
9649 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9651 Return a service that installs a configuration file for the
9652 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9653 @code{pam_limits} module}. The procedure optionally takes a list of
9654 @code{pam-limits-entry} values, which can be used to specify
9655 @code{ulimit} limits and nice priority limits to user sessions.
9657 The following limits definition sets two hard and soft limits for all
9658 login sessions of users in the @code{realtime} group:
9663 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9664 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9667 The first entry increases the maximum realtime priority for
9668 non-privileged processes; the second entry lifts any restriction of the
9669 maximum address space that can be locked in memory. These settings are
9670 commonly used for real-time audio systems.
9673 @node Scheduled Job Execution
9674 @subsubsection Scheduled Job Execution
9678 @cindex scheduling jobs
9679 The @code{(gnu services mcron)} module provides an interface to
9680 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9681 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9682 Unix @command{cron} daemon; the main difference is that it is
9683 implemented in Guile Scheme, which provides a lot of flexibility when
9684 specifying the scheduling of jobs and their actions.
9686 The example below defines an operating system that runs the
9687 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9688 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9689 well as the @command{mkid} command on behalf of an unprivileged user
9690 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9691 gexps to introduce job definitions that are passed to mcron
9692 (@pxref{G-Expressions}).
9695 (use-modules (guix) (gnu) (gnu services mcron))
9696 (use-package-modules base idutils)
9698 (define updatedb-job
9699 ;; Run 'updatedb' at 3AM every day. Here we write the
9700 ;; job's action as a Scheme procedure.
9701 #~(job '(next-hour '(3))
9703 (execl (string-append #$findutils "/bin/updatedb")
9705 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9707 (define garbage-collector-job
9708 ;; Collect garbage 5 minutes after midnight every day.
9709 ;; The job's action is a shell command.
9710 #~(job "5 0 * * *" ;Vixie cron syntax
9714 ;; Update the index database as user "charlie" at 12:15PM
9715 ;; and 19:15PM. This runs from the user's home directory.
9716 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9717 (string-append #$idutils "/bin/mkid src")
9722 (services (cons (mcron-service (list garbage-collector-job
9728 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9729 for more information on mcron job specifications. Below is the
9730 reference of the mcron service.
9732 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9733 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9734 list of gexps denoting mcron job specifications.
9736 This is a shorthand for:
9738 (service mcron-service-type
9739 (mcron-configuration (mcron mcron) (jobs jobs)))
9743 @defvr {Scheme Variable} mcron-service-type
9744 This is the type of the @code{mcron} service, whose value is an
9745 @code{mcron-configuration} object.
9747 This service type can be the target of a service extension that provides
9748 it additional job specifications (@pxref{Service Composition}). In
9749 other words, it is possible to define services that provide additional
9753 @deftp {Data Type} mcron-configuration
9754 Data type representing the configuration of mcron.
9757 @item @code{mcron} (default: @var{mcron2})
9758 The mcron package to use.
9761 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9762 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9763 specifications,, mcron, GNU@tie{}mcron}).
9769 @subsubsection Log Rotation
9772 @cindex log rotation
9774 Log files such as those found in @file{/var/log} tend to grow endlessly,
9775 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9776 their contents in separate files, possibly compressed. The @code{(gnu
9777 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9778 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9780 The example below defines an operating system that provides log rotation
9781 with the default settings, for commonly encountered log files.
9784 (use-modules (guix) (gnu))
9785 (use-service-modules admin mcron)
9786 (use-package-modules base idutils)
9790 (services (cons* (mcron-service)
9791 (service rottlog-service-type)
9795 @defvr {Scheme Variable} rottlog-service-type
9796 This is the type of the Rottlog service, whose value is a
9797 @code{rottlog-configuration} object.
9799 Other services can extend this one with new @code{log-rotation} objects
9800 (see below), thereby augmenting the set of files to be rotated.
9802 This service type can define mcron jobs (@pxref{Scheduled Job
9803 Execution}) to run the rottlog service.
9806 @deftp {Data Type} rottlog-configuration
9807 Data type representing the configuration of rottlog.
9810 @item @code{rottlog} (default: @code{rottlog})
9811 The Rottlog package to use.
9813 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9814 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9815 rottlog, GNU Rot[t]log Manual}).
9817 @item @code{rotations} (default: @code{%default-rotations})
9818 A list of @code{log-rotation} objects as defined below.
9821 This is a list of gexps where each gexp corresponds to an mcron job
9822 specification (@pxref{Scheduled Job Execution}).
9826 @deftp {Data Type} log-rotation
9827 Data type representing the rotation of a group of log files.
9829 Taking an example from the Rottlog manual (@pxref{Period Related File
9830 Examples,,, rottlog, GNU Rot[t]log Manual}), a log rotation might be
9836 (files '("/var/log/apache/*"))
9837 (options '("storedir apache-archives"
9843 The list of fields is as follows:
9846 @item @code{frequency} (default: @code{'weekly})
9847 The log rotation frequency, a symbol.
9850 The list of files or file glob patterns to rotate.
9852 @item @code{options} (default: @code{'()})
9853 The list of rottlog options for this rotation (@pxref{Configuration
9854 parameters,,, rottlog, GNU Rot[t]lg Manual}).
9856 @item @code{post-rotate} (default: @code{#f})
9857 Either @code{#f} or a gexp to execute once the rotation has completed.
9861 @defvr {Scheme Variable} %default-rotations
9862 Specifies weekly rotation of @var{%rotated-files} and
9863 a couple of other files.
9866 @defvr {Scheme Variable} %rotated-files
9867 The list of syslog-controlled files to be rotated. By default it is:
9868 @code{'("/var/log/messages" "/var/log/secure")}.
9871 @node Networking Services
9872 @subsubsection Networking Services
9874 The @code{(gnu services networking)} module provides services to configure
9875 the network interface.
9877 @cindex DHCP, networking service
9878 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9879 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9880 Protocol (DHCP) client, on all the non-loopback network interfaces.
9883 @defvr {Scheme Variable} static-networking-service-type
9884 This is the type for statically-configured network interfaces.
9885 @c TODO Document <static-networking> data structures.
9888 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9889 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9890 Return a service that starts @var{interface} with address @var{ip}. If
9891 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9892 it must be a string specifying the default network gateway.
9894 This procedure can be called several times, one for each network
9895 interface of interest. Behind the scenes what it does is extend
9896 @code{static-networking-service-type} with additional network interfaces
9903 @cindex network management
9904 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9905 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9906 management daemon that aims to simplify wired and wireless networking.
9908 This service adds the @var{wicd} package to the global profile, providing
9909 several commands to interact with the daemon and configure networking:
9910 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9911 and @command{wicd-curses} user interfaces.
9914 @cindex NetworkManager
9916 @defvr {Scheme Variable} network-manager-service-type
9917 This is the service type for the
9918 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9919 service. The value for this service type is a
9920 @code{network-manager-configuration} record.
9923 @deftp {Data Type} network-manager-configuration
9924 Data type representing the configuration of NetworkManager.
9927 @item @code{network-manager} (default: @code{network-manager})
9928 The NetworkManager package to use.
9930 @item @code{dns} (default: @code{"default"})
9931 Processing mode for DNS, which affects how NetworkManager uses the
9932 @code{resolv.conf} configuration file.
9936 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9937 provided by currently active connections.
9940 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9941 using a "split DNS" configuration if you are connected to a VPN, and
9942 then update @code{resolv.conf} to point to the local nameserver.
9945 NetworkManager will not modify @code{resolv.conf}.
9952 @deffn {Scheme Variable} connman-service-type
9953 This is the service type to run @url{https://01.org/connman,Connman},
9954 a network connection manager.
9956 Its value must be an
9957 @code{connman-configuration} record as in this example:
9960 (service connman-service-type
9961 (connman-configuration
9965 See below for details about @code{connman-configuration}.
9968 @deftp {Data Type} connman-configuration
9969 Data Type representing the configuration of connman.
9972 @item @code{connman} (default: @var{connman})
9973 The connman package to use.
9975 @item @code{disable-vpn?} (default: @code{#f})
9976 When true, enable connman's vpn plugin.
9980 @cindex WPA Supplicant
9981 @defvr {Scheme Variable} wpa-supplicant-service-type
9982 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9983 supplicant}, an authentication daemon required to authenticate against
9984 encrypted WiFi or ethernet networks. It is configured to listen for
9987 The value of this service is the @code{wpa-supplicant} package to use.
9988 Thus, it can be instantiated like this:
9991 (use-modules (gnu services networking))
9993 (service wpa-supplicant-service-type)
9998 @cindex real time clock
9999 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
10000 [#:servers @var{%ntp-servers}] @
10001 [#:allow-large-adjustment? #f]
10002 Return a service that runs the daemon from @var{ntp}, the
10003 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
10004 keep the system clock synchronized with that of @var{servers}.
10005 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
10006 make an initial adjustment of more than 1,000 seconds.
10009 @defvr {Scheme Variable} %ntp-servers
10010 List of host names used as the default NTP servers.
10014 @deffn {Scheme variable} inetd-service-type
10015 This service runs the @command{inetd} (@pxref{inetd invocation,,,
10016 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
10017 connections on internet sockets, and lazily starts the specified server
10018 program when a connection is made on one of these sockets.
10020 The value of this service is an @code{inetd-configuration} object. The
10021 following example configures the @command{inetd} daemon to provide the
10022 built-in @command{echo} service, as well as an smtp service which
10023 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
10024 gateway @code{hostname}:
10029 (inetd-configuration
10033 (socket-type 'stream)
10040 (socket-type 'stream)
10044 (program (file-append openssh "/bin/ssh"))
10046 '("ssh" "-qT" "-i" "/path/to/ssh_key"
10047 "-W" "smtp-server:25" "user@@hostname")))))
10050 See below for more details about @code{inetd-configuration}.
10053 @deftp {Data Type} inetd-configuration
10054 Data type representing the configuration of @command{inetd}.
10057 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
10058 The @command{inetd} executable to use.
10060 @item @code{entries} (default: @code{'()})
10061 A list of @command{inetd} service entries. Each entry should be created
10062 by the @code{inetd-entry} constructor.
10066 @deftp {Data Type} inetd-entry
10067 Data type representing an entry in the @command{inetd} configuration.
10068 Each entry corresponds to a socket where @command{inetd} will listen for
10072 @item @code{node} (default: @code{#f})
10073 Optional string, a comma-separated list of local addresses
10074 @command{inetd} should use when listening for this service.
10075 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
10076 description of all options.
10078 A string, the name must correspond to an entry in @code{/etc/services}.
10079 @item @code{socket-type}
10080 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
10082 @item @code{protocol}
10083 A string, must correspond to an entry in @code{/etc/protocols}.
10084 @item @code{wait?} (default: @code{#t})
10085 Whether @command{inetd} should wait for the server to exit before
10086 listening to new service requests.
10088 A string containing the user (and, optionally, group) name of the user
10089 as whom the server should run. The group name can be specified in a
10090 suffix, separated by a colon or period, i.e. @code{"user"},
10091 @code{"user:group"} or @code{"user.group"}.
10092 @item @code{program} (default: @code{"internal"})
10093 The server program which will serve the requests, or @code{"internal"}
10094 if @command{inetd} should use a built-in service.
10095 @item @code{arguments} (default: @code{'()})
10096 A list strings or file-like objects, which are the server program's
10097 arguments, starting with the zeroth argument, i.e. the name of the
10098 program itself. For @command{inetd}'s internal services, this entry
10099 must be @code{'()} or @code{'("internal")}.
10102 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
10103 detailed discussion of each configuration field.
10107 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
10108 Return a service to run the @uref{https://torproject.org, Tor} anonymous
10111 The daemon runs as the @code{tor} unprivileged user. It is passed
10112 @var{config-file}, a file-like object, with an additional @code{User tor} line
10113 and lines for hidden services added via @code{tor-hidden-service}. Run
10114 @command{man tor} for information about the configuration file.
10117 @cindex hidden service
10118 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
10119 Define a new Tor @dfn{hidden service} called @var{name} and implementing
10120 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
10123 '((22 "127.0.0.1:22")
10124 (80 "127.0.0.1:8080"))
10127 In this example, port 22 of the hidden service is mapped to local port 22, and
10128 port 80 is mapped to local port 8080.
10130 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
10131 the @file{hostname} file contains the @code{.onion} host name for the hidden
10134 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
10135 project's documentation} for more information.
10138 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
10139 [#:interface "127.0.0.1"] [#:port 6667] @
10140 [#:extra-settings ""]
10141 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
10142 acts as a gateway between IRC and chat networks.
10144 The daemon will listen to the interface corresponding to the IP address
10145 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
10146 local clients can connect, whereas @code{0.0.0.0} means that connections can
10147 come from any networking interface.
10149 In addition, @var{extra-settings} specifies a string to append to the
10150 configuration file.
10153 Furthermore, @code{(gnu services ssh)} provides the following services.
10157 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
10158 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
10159 [#:allow-empty-passwords? #f] [#:root-login? #f] @
10160 [#:syslog-output? #t] [#:x11-forwarding? #t] @
10161 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
10162 [#:public-key-authentication? #t] [#:initialize? #t]
10163 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
10164 @var{host-key} must designate a file containing the host key, and readable
10167 When @var{daemonic?} is true, @command{lshd} will detach from the
10168 controlling terminal and log its output to syslogd, unless one sets
10169 @var{syslog-output?} to false. Obviously, it also makes lsh-service
10170 depend on existence of syslogd service. When @var{pid-file?} is true,
10171 @command{lshd} writes its PID to the file called @var{pid-file}.
10173 When @var{initialize?} is true, automatically create the seed and host key
10174 upon service activation if they do not exist yet. This may take long and
10175 require interaction.
10177 When @var{initialize?} is false, it is up to the user to initialize the
10178 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
10179 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
10180 basics,,, lsh, LSH Manual}).
10182 When @var{interfaces} is empty, lshd listens for connections on all the
10183 network interfaces; otherwise, @var{interfaces} must be a list of host names
10186 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
10187 passwords, and @var{root-login?} specifies whether to accept log-ins as
10190 The other options should be self-descriptive.
10195 @deffn {Scheme Variable} openssh-service-type
10196 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
10197 shell daemon, @command{sshd}. Its value must be an
10198 @code{openssh-configuration} record as in this example:
10201 (service openssh-service-type
10202 (openssh-configuration
10203 (x11-forwarding? #t)
10204 (permit-root-login 'without-password)))
10207 See below for details about @code{openssh-configuration}.
10210 @deftp {Data Type} openssh-configuration
10211 This is the configuration record for OpenSSH's @command{sshd}.
10214 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
10215 Name of the file where @command{sshd} writes its PID.
10217 @item @code{port-number} (default: @code{22})
10218 TCP port on which @command{sshd} listens for incoming connections.
10220 @item @code{permit-root-login} (default: @code{#f})
10221 This field determines whether and when to allow logins as root. If
10222 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
10223 If it's the symbol @code{'without-password}, then root logins are
10224 permitted but not with password-based authentication.
10226 @item @code{allow-empty-passwords?} (default: @code{#f})
10227 When true, users with empty passwords may log in. When false, they may
10230 @item @code{password-authentication?} (default: @code{#t})
10231 When true, users may log in with their password. When false, they have
10232 other authentication methods.
10234 @item @code{public-key-authentication?} (default: @code{#t})
10235 When true, users may log in using public key authentication. When
10236 false, users have to use other authentication method.
10238 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
10239 This is used only by protocol version 2.
10241 @item @code{x11-forwarding?} (default: @code{#f})
10242 When true, forwarding of X11 graphical client connections is
10243 enabled---in other words, @command{ssh} options @option{-X} and
10244 @option{-Y} will work.
10246 @item @code{challenge-response-authentication?} (default: @code{#f})
10247 Specifies whether challenge response authentication is allowed (e.g. via
10250 @item @code{use-pam?} (default: @code{#t})
10251 Enables the Pluggable Authentication Module interface. If set to
10252 @code{#t}, this will enable PAM authentication using
10253 @code{challenge-response-authentication?} and
10254 @code{password-authentication?}, in addition to PAM account and session
10255 module processing for all authentication types.
10257 Because PAM challenge response authentication usually serves an
10258 equivalent role to password authentication, you should disable either
10259 @code{challenge-response-authentication?} or
10260 @code{password-authentication?}.
10262 @item @code{print-last-log?} (default: @code{#t})
10263 Specifies whether @command{sshd} should print the date and time of the
10264 last user login when a user logs in interactively.
10266 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
10267 Configures external subsystems (e.g. file transfer daemon).
10269 This is a list of two-element lists, each of which containing the
10270 subsystem name and a command (with optional arguments) to execute upon
10273 The command @command{internal-sftp} implements an in-process SFTP
10274 server. Alternately, one can specify the @command{sftp-server} command:
10276 (service openssh-service-type
10277 (openssh-configuration
10279 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
10284 @deffn {Scheme Procedure} dropbear-service [@var{config}]
10285 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
10286 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
10289 For example, to specify a Dropbear service listening on port 1234, add
10290 this call to the operating system's @code{services} field:
10293 (dropbear-service (dropbear-configuration
10294 (port-number 1234)))
10298 @deftp {Data Type} dropbear-configuration
10299 This data type represents the configuration of a Dropbear SSH daemon.
10302 @item @code{dropbear} (default: @var{dropbear})
10303 The Dropbear package to use.
10305 @item @code{port-number} (default: 22)
10306 The TCP port where the daemon waits for incoming connections.
10308 @item @code{syslog-output?} (default: @code{#t})
10309 Whether to enable syslog output.
10311 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10312 File name of the daemon's PID file.
10314 @item @code{root-login?} (default: @code{#f})
10315 Whether to allow @code{root} logins.
10317 @item @code{allow-empty-passwords?} (default: @code{#f})
10318 Whether to allow empty passwords.
10320 @item @code{password-authentication?} (default: @code{#t})
10321 Whether to enable password-based authentication.
10325 @defvr {Scheme Variable} %facebook-host-aliases
10326 This variable contains a string for use in @file{/etc/hosts}
10327 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10328 line contains a entry that maps a known server name of the Facebook
10329 on-line service---e.g., @code{www.facebook.com}---to the local
10330 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10332 This variable is typically used in the @code{hosts-file} field of an
10333 @code{operating-system} declaration (@pxref{operating-system Reference,
10334 @file{/etc/hosts}}):
10337 (use-modules (gnu) (guix))
10340 (host-name "mymachine")
10343 ;; Create a /etc/hosts file with aliases for "localhost"
10344 ;; and "mymachine", as well as for Facebook servers.
10345 (plain-file "hosts"
10346 (string-append (local-host-aliases host-name)
10347 %facebook-host-aliases))))
10350 This mechanism can prevent programs running locally, such as Web
10351 browsers, from accessing Facebook.
10354 The @code{(gnu services avahi)} provides the following definition.
10356 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10357 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10358 [#:ipv6? #t] [#:wide-area? #f] @
10359 [#:domains-to-browse '()] [#:debug? #f]
10360 Return a service that runs @command{avahi-daemon}, a system-wide
10361 mDNS/DNS-SD responder that allows for service discovery and
10362 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10363 extends the name service cache daemon (nscd) so that it can resolve
10364 @code{.local} host names using
10365 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10366 add the @var{avahi} package to the system profile so that commands such as
10367 @command{avahi-browse} are directly usable.
10369 If @var{host-name} is different from @code{#f}, use that as the host name to
10370 publish for this machine; otherwise, use the machine's actual host name.
10372 When @var{publish?} is true, publishing of host names and services is allowed;
10373 in particular, avahi-daemon will publish the machine's host name and IP
10374 address via mDNS on the local network.
10376 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10378 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10382 @deffn {Scheme Variable} openvswitch-service-type
10383 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10384 service, whose value should be an @code{openvswitch-configuration}
10388 @deftp {Data Type} openvswitch-configuration
10389 Data type representing the configuration of Open vSwitch, a multilayer
10390 virtual switch which is designed to enable massive network automation
10391 through programmatic extension.
10394 @item @code{package} (default: @var{openvswitch})
10395 Package object of the Open vSwitch.
10401 @subsubsection X Window
10404 @cindex X Window System
10405 Support for the X Window graphical display system---specifically
10406 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10407 there is no @code{xorg-service} procedure. Instead, the X server is
10408 started by the @dfn{login manager}, currently SLiM.
10410 @deftp {Data Type} sddm-configuration
10411 This is the data type representing the sddm service configuration.
10414 @item @code{display-server} (default: "x11")
10415 Select display server to use for the greeter. Valid values are "x11"
10418 @item @code{numlock} (default: "on")
10419 Valid values are "on", "off" or "none".
10421 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10422 Command to run when halting.
10424 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10425 Command to run when rebooting.
10427 @item @code{theme} (default "maldives")
10428 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10430 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10431 Directory to look for themes.
10433 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10434 Directory to look for faces.
10436 @item @code{default-path} (default "/run/current-system/profile/bin")
10437 Default PATH to use.
10439 @item @code{minimum-uid} (default 1000)
10440 Minimum UID to display in SDDM.
10442 @item @code{maximum-uid} (default 2000)
10443 Maximum UID to display in SDDM
10445 @item @code{remember-last-user?} (default #t)
10446 Remember last user.
10448 @item @code{remember-last-session?} (default #t)
10449 Remember last session.
10451 @item @code{hide-users} (default "")
10452 Usernames to hide from SDDM greeter.
10454 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10455 Users with shells listed will be hidden from the SDDM greeter.
10457 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10458 Script to run before starting a wayland session.
10460 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10461 Directory to look for desktop files starting wayland sessions.
10463 @item @code{xorg-server-path} (default @code{xorg-start-command})
10464 Path to xorg-server.
10466 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10469 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10472 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10473 Script to run after starting xorg-server.
10475 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10476 Script to run before stopping xorg-server.
10478 @item @code{xsession-command} (default: @code{xinitr })
10479 Script to run before starting a X session.
10481 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10482 Directory to look for desktop files starting X sessions.
10484 @item @code{minimum-vt} (default: 7)
10487 @item @code{xserver-arguments} (default "-nolisten tcp")
10488 Arguments to pass to xorg-server.
10490 @item @code{auto-login-user} (default "")
10491 User to use for auto-login.
10493 @item @code{auto-login-session} (default "")
10494 Desktop file to use for auto-login.
10496 @item @code{relogin?} (default #f)
10497 Relogin after logout.
10502 @cindex login manager
10503 @deffn {Scheme Procedure} sddm-service config
10504 Return a service that spawns the SDDM graphical login manager for config of
10505 type @code{<sddm-configuration>}.
10508 (sddm-service (sddm-configuration
10509 (auto-login-user "Alice")
10510 (auto-login-session "xfce.desktop")))
10514 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10515 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10516 [#:theme @var{%default-slim-theme}] @
10517 [#:theme-name @var{%default-slim-theme-name}]
10518 Return a service that spawns the SLiM graphical login manager, which in
10519 turn starts the X display server with @var{startx}, a command as returned by
10520 @code{xorg-start-command}.
10524 SLiM automatically looks for session types described by the @file{.desktop}
10525 files in @file{/run/current-system/profile/share/xsessions} and allows users
10526 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10527 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10528 adding them to the system-wide set of packages automatically makes them
10529 available at the log-in screen.
10531 In addition, @file{~/.xsession} files are honored. When available,
10532 @file{~/.xsession} must be an executable that starts a window manager
10533 and/or other X clients.
10535 When @var{allow-empty-passwords?} is true, allow logins with an empty
10536 password. When @var{auto-login?} is true, log in automatically as
10537 @var{default-user}.
10539 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10540 @var{theme} must be a gexp denoting the name of a directory containing the
10541 theme to use. In that case, @var{theme-name} specifies the name of the
10545 @defvr {Scheme Variable} %default-theme
10546 @defvrx {Scheme Variable} %default-theme-name
10547 The G-Expression denoting the default SLiM theme and its name.
10550 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10551 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10552 Return a derivation that builds a @var{guile} script to start the X server
10553 from @var{xorg-server}. @var{configuration-file} is the server configuration
10554 file or a derivation that builds it; when omitted, the result of
10555 @code{xorg-configuration-file} is used.
10557 Usually the X server is started by a login manager.
10560 @deffn {Scheme Procedure} xorg-configuration-file @
10561 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10562 Return a configuration file for the Xorg server containing search paths for
10563 all the common drivers.
10565 @var{drivers} must be either the empty list, in which case Xorg chooses a
10566 graphics driver automatically, or a list of driver names that will be tried in
10567 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10569 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10570 appropriate screen resolution; otherwise, it must be a list of
10571 resolutions---e.g., @code{((1024 768) (640 480))}.
10573 Last, @var{extra-config} is a list of strings or objects appended to the
10574 @code{text-file*} argument list. It is used to pass extra text to be added
10575 verbatim to the configuration file.
10578 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10579 Add @var{package}, a package for a screen-locker or screen-saver whose
10580 command is @var{program}, to the set of setuid programs and add a PAM entry
10581 for it. For example:
10584 (screen-locker-service xlockmore "xlock")
10587 makes the good ol' XlockMore usable.
10591 @node Printing Services
10592 @subsubsection Printing Services
10594 @cindex printer support with CUPS
10595 The @code{(gnu services cups)} module provides a Guix service definition
10596 for the CUPS printing service. To add printer support to a GuixSD
10597 system, add a @code{cups-service} to the operating system definition:
10599 @deffn {Scheme Variable} cups-service-type
10600 The service type for the CUPS print server. Its value should be a valid
10601 CUPS configuration (see below). To use the default settings, simply
10604 (service cups-service-type)
10608 The CUPS configuration controls the basic things about your CUPS
10609 installation: what interfaces it listens on, what to do if a print job
10610 fails, how much logging to do, and so on. To actually add a printer,
10611 you have to visit the @url{http://localhost:631} URL, or use a tool such
10612 as GNOME's printer configuration services. By default, configuring a
10613 CUPS service will generate a self-signed certificate if needed, for
10614 secure connections to the print server.
10616 Suppose you want to enable the Web interface of CUPS and also add
10617 support for HP printers @i{via} the @code{hplip} package. You can do
10618 that directly, like this (you need to use the @code{(gnu packages cups)}
10622 (service cups-service-type
10623 (cups-configuration
10624 (web-interface? #t)
10626 (list cups-filters hplip))))
10629 The available configuration parameters follow. Each parameter
10630 definition is preceded by its type; for example, @samp{string-list foo}
10631 indicates that the @code{foo} parameter should be specified as a list of
10632 strings. There is also a way to specify the configuration as a string,
10633 if you have an old @code{cupsd.conf} file that you want to port over
10634 from some other system; see the end for more details.
10636 @c The following documentation was initially generated by
10637 @c (generate-documentation) in (gnu services cups). Manually maintained
10638 @c documentation is better, so we shouldn't hesitate to edit below as
10639 @c needed. However if the change you want to make to this documentation
10640 @c can be done in an automated way, it's probably easier to change
10641 @c (generate-documentation) than to make it below and have to deal with
10642 @c the churn as CUPS updates.
10645 Available @code{cups-configuration} fields are:
10647 @deftypevr {@code{cups-configuration} parameter} package cups
10651 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10652 Drivers and other extensions to the CUPS package.
10655 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10656 Configuration of where to write logs, what directories to use for print
10657 spools, and related privileged configuration parameters.
10659 Available @code{files-configuration} fields are:
10661 @deftypevr {@code{files-configuration} parameter} log-location access-log
10662 Defines the access log filename. Specifying a blank filename disables
10663 access log generation. The value @code{stderr} causes log entries to be
10664 sent to the standard error file when the scheduler is running in the
10665 foreground, or to the system log daemon when run in the background. The
10666 value @code{syslog} causes log entries to be sent to the system log
10667 daemon. The server name may be included in filenames using the string
10668 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10670 Defaults to @samp{"/var/log/cups/access_log"}.
10673 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10674 Where CUPS should cache data.
10676 Defaults to @samp{"/var/cache/cups"}.
10679 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10680 Specifies the permissions for all configuration files that the scheduler
10683 Note that the permissions for the printers.conf file are currently
10684 masked to only allow access from the scheduler user (typically root).
10685 This is done because printer device URIs sometimes contain sensitive
10686 authentication information that should not be generally known on the
10687 system. There is no way to disable this security feature.
10689 Defaults to @samp{"0640"}.
10692 @deftypevr {@code{files-configuration} parameter} log-location error-log
10693 Defines the error log filename. Specifying a blank filename disables
10694 access log generation. The value @code{stderr} causes log entries to be
10695 sent to the standard error file when the scheduler is running in the
10696 foreground, or to the system log daemon when run in the background. The
10697 value @code{syslog} causes log entries to be sent to the system log
10698 daemon. The server name may be included in filenames using the string
10699 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10701 Defaults to @samp{"/var/log/cups/error_log"}.
10704 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10705 Specifies which errors are fatal, causing the scheduler to exit. The
10710 No errors are fatal.
10713 All of the errors below are fatal.
10716 Browsing initialization errors are fatal, for example failed connections
10717 to the DNS-SD daemon.
10720 Configuration file syntax errors are fatal.
10723 Listen or Port errors are fatal, except for IPv6 failures on the
10724 loopback or @code{any} addresses.
10727 Log file creation or write errors are fatal.
10730 Bad startup file permissions are fatal, for example shared TLS
10731 certificate and key files with world-read permissions.
10734 Defaults to @samp{"all -browse"}.
10737 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10738 Specifies whether the file pseudo-device can be used for new printer
10739 queues. The URI @uref{file:///dev/null} is always allowed.
10741 Defaults to @samp{#f}.
10744 @deftypevr {@code{files-configuration} parameter} string group
10745 Specifies the group name or ID that will be used when executing external
10748 Defaults to @samp{"lp"}.
10751 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10752 Specifies the permissions for all log files that the scheduler writes.
10754 Defaults to @samp{"0644"}.
10757 @deftypevr {@code{files-configuration} parameter} log-location page-log
10758 Defines the page log filename. Specifying a blank filename disables
10759 access log generation. The value @code{stderr} causes log entries to be
10760 sent to the standard error file when the scheduler is running in the
10761 foreground, or to the system log daemon when run in the background. The
10762 value @code{syslog} causes log entries to be sent to the system log
10763 daemon. The server name may be included in filenames using the string
10764 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10766 Defaults to @samp{"/var/log/cups/page_log"}.
10769 @deftypevr {@code{files-configuration} parameter} string remote-root
10770 Specifies the username that is associated with unauthenticated accesses
10771 by clients claiming to be the root user. The default is @code{remroot}.
10773 Defaults to @samp{"remroot"}.
10776 @deftypevr {@code{files-configuration} parameter} file-name request-root
10777 Specifies the directory that contains print jobs and other HTTP request
10780 Defaults to @samp{"/var/spool/cups"}.
10783 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10784 Specifies the level of security sandboxing that is applied to print
10785 filters, backends, and other child processes of the scheduler; either
10786 @code{relaxed} or @code{strict}. This directive is currently only
10787 used/supported on macOS.
10789 Defaults to @samp{strict}.
10792 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10793 Specifies the location of TLS certificates and private keys. CUPS will
10794 look for public and private keys in this directory: a @code{.crt} files
10795 for PEM-encoded certificates and corresponding @code{.key} files for
10796 PEM-encoded private keys.
10798 Defaults to @samp{"/etc/cups/ssl"}.
10801 @deftypevr {@code{files-configuration} parameter} file-name server-root
10802 Specifies the directory containing the server configuration files.
10804 Defaults to @samp{"/etc/cups"}.
10807 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10808 Specifies whether the scheduler calls fsync(2) after writing
10809 configuration or state files.
10811 Defaults to @samp{#f}.
10814 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10815 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10818 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10819 Specifies the directory where temporary files are stored.
10821 Defaults to @samp{"/var/spool/cups/tmp"}.
10824 @deftypevr {@code{files-configuration} parameter} string user
10825 Specifies the user name or ID that is used when running external
10828 Defaults to @samp{"lp"}.
10832 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10833 Specifies the logging level for the AccessLog file. The @code{config}
10834 level logs when printers and classes are added, deleted, or modified and
10835 when configuration files are accessed or updated. The @code{actions}
10836 level logs when print jobs are submitted, held, released, modified, or
10837 canceled, and any of the conditions for @code{config}. The @code{all}
10838 level logs all requests.
10840 Defaults to @samp{actions}.
10843 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10844 Specifies whether to purge job history data automatically when it is no
10845 longer required for quotas.
10847 Defaults to @samp{#f}.
10850 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10851 Specifies which protocols to use for local printer sharing.
10853 Defaults to @samp{dnssd}.
10856 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10857 Specifies whether the CUPS web interface is advertised.
10859 Defaults to @samp{#f}.
10862 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10863 Specifies whether shared printers are advertised.
10865 Defaults to @samp{#f}.
10868 @deftypevr {@code{cups-configuration} parameter} string classification
10869 Specifies the security classification of the server. Any valid banner
10870 name can be used, including "classified", "confidential", "secret",
10871 "topsecret", and "unclassified", or the banner can be omitted to disable
10872 secure printing functions.
10874 Defaults to @samp{""}.
10877 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10878 Specifies whether users may override the classification (cover page) of
10879 individual print jobs using the @code{job-sheets} option.
10881 Defaults to @samp{#f}.
10884 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10885 Specifies the default type of authentication to use.
10887 Defaults to @samp{Basic}.
10890 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10891 Specifies whether encryption will be used for authenticated requests.
10893 Defaults to @samp{Required}.
10896 @deftypevr {@code{cups-configuration} parameter} string default-language
10897 Specifies the default language to use for text and web content.
10899 Defaults to @samp{"en"}.
10902 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10903 Specifies the default paper size for new print queues. @samp{"Auto"}
10904 uses a locale-specific default, while @samp{"None"} specifies there is
10905 no default paper size. Specific size names are typically
10906 @samp{"Letter"} or @samp{"A4"}.
10908 Defaults to @samp{"Auto"}.
10911 @deftypevr {@code{cups-configuration} parameter} string default-policy
10912 Specifies the default access policy to use.
10914 Defaults to @samp{"default"}.
10917 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10918 Specifies whether local printers are shared by default.
10920 Defaults to @samp{#t}.
10923 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10924 Specifies the delay for updating of configuration and state files, in
10925 seconds. A value of 0 causes the update to happen as soon as possible,
10926 typically within a few milliseconds.
10928 Defaults to @samp{30}.
10931 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10932 Specifies what to do when an error occurs. Possible values are
10933 @code{abort-job}, which will discard the failed print job;
10934 @code{retry-job}, which will retry the job at a later time;
10935 @code{retry-this-job}, which retries the failed job immediately; and
10936 @code{stop-printer}, which stops the printer.
10938 Defaults to @samp{stop-printer}.
10941 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10942 Specifies the maximum cost of filters that are run concurrently, which
10943 can be used to minimize disk, memory, and CPU resource problems. A
10944 limit of 0 disables filter limiting. An average print to a
10945 non-PostScript printer needs a filter limit of about 200. A PostScript
10946 printer needs about half that (100). Setting the limit below these
10947 thresholds will effectively limit the scheduler to printing a single job
10950 Defaults to @samp{0}.
10953 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10954 Specifies the scheduling priority of filters that are run to print a
10955 job. The nice value ranges from 0, the highest priority, to 19, the
10958 Defaults to @samp{0}.
10961 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10962 Specifies whether to do reverse lookups on connecting clients. The
10963 @code{double} setting causes @code{cupsd} to verify that the hostname
10964 resolved from the address matches one of the addresses returned for that
10965 hostname. Double lookups also prevent clients with unregistered
10966 addresses from connecting to your server. Only set this option to
10967 @code{#t} or @code{double} if absolutely required.
10969 Defaults to @samp{#f}.
10972 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10973 Specifies the number of seconds to wait before killing the filters and
10974 backend associated with a canceled or held job.
10976 Defaults to @samp{30}.
10979 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10980 Specifies the interval between retries of jobs in seconds. This is
10981 typically used for fax queues but can also be used with normal print
10982 queues whose error policy is @code{retry-job} or
10983 @code{retry-current-job}.
10985 Defaults to @samp{30}.
10988 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10989 Specifies the number of retries that are done for jobs. This is
10990 typically used for fax queues but can also be used with normal print
10991 queues whose error policy is @code{retry-job} or
10992 @code{retry-current-job}.
10994 Defaults to @samp{5}.
10997 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10998 Specifies whether to support HTTP keep-alive connections.
11000 Defaults to @samp{#t}.
11003 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
11004 Specifies how long an idle client connection remains open, in seconds.
11006 Defaults to @samp{30}.
11009 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
11010 Specifies the maximum size of print files, IPP requests, and HTML form
11011 data. A limit of 0 disables the limit check.
11013 Defaults to @samp{0}.
11016 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
11017 Listens on the specified interfaces for connections. Valid values are
11018 of the form @var{address}:@var{port}, where @var{address} is either an
11019 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
11020 indicate all addresses. Values can also be file names of local UNIX
11021 domain sockets. The Listen directive is similar to the Port directive
11022 but allows you to restrict access to specific interfaces or networks.
11025 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
11026 Specifies the number of pending connections that will be allowed. This
11027 normally only affects very busy servers that have reached the MaxClients
11028 limit, but can also be triggered by large numbers of simultaneous
11029 connections. When the limit is reached, the operating system will
11030 refuse additional connections until the scheduler can accept the pending
11033 Defaults to @samp{128}.
11036 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
11037 Specifies a set of additional access controls.
11039 Available @code{location-access-controls} fields are:
11041 @deftypevr {@code{location-access-controls} parameter} file-name path
11042 Specifies the URI path to which the access control applies.
11045 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
11046 Access controls for all access to this path, in the same format as the
11047 @code{access-controls} of @code{operation-access-control}.
11049 Defaults to @samp{()}.
11052 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
11053 Access controls for method-specific access to this path.
11055 Defaults to @samp{()}.
11057 Available @code{method-access-controls} fields are:
11059 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
11060 If @code{#t}, apply access controls to all methods except the listed
11061 methods. Otherwise apply to only the listed methods.
11063 Defaults to @samp{#f}.
11066 @deftypevr {@code{method-access-controls} parameter} method-list methods
11067 Methods to which this access control applies.
11069 Defaults to @samp{()}.
11072 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
11073 Access control directives, as a list of strings. Each string should be
11074 one directive, such as "Order allow,deny".
11076 Defaults to @samp{()}.
11081 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
11082 Specifies the number of debugging messages that are retained for logging
11083 if an error occurs in a print job. Debug messages are logged regardless
11084 of the LogLevel setting.
11086 Defaults to @samp{100}.
11089 @deftypevr {@code{cups-configuration} parameter} log-level log-level
11090 Specifies the level of logging for the ErrorLog file. The value
11091 @code{none} stops all logging while @code{debug2} logs everything.
11093 Defaults to @samp{info}.
11096 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
11097 Specifies the format of the date and time in the log files. The value
11098 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
11100 Defaults to @samp{standard}.
11103 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
11104 Specifies the maximum number of simultaneous clients that are allowed by
11107 Defaults to @samp{100}.
11110 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
11111 Specifies the maximum number of simultaneous clients that are allowed
11112 from a single address.
11114 Defaults to @samp{100}.
11117 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
11118 Specifies the maximum number of copies that a user can print of each
11121 Defaults to @samp{9999}.
11124 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
11125 Specifies the maximum time a job may remain in the @code{indefinite}
11126 hold state before it is canceled. A value of 0 disables cancellation of
11129 Defaults to @samp{0}.
11132 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
11133 Specifies the maximum number of simultaneous jobs that are allowed. Set
11134 to 0 to allow an unlimited number of jobs.
11136 Defaults to @samp{500}.
11139 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
11140 Specifies the maximum number of simultaneous jobs that are allowed per
11141 printer. A value of 0 allows up to MaxJobs jobs per printer.
11143 Defaults to @samp{0}.
11146 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
11147 Specifies the maximum number of simultaneous jobs that are allowed per
11148 user. A value of 0 allows up to MaxJobs jobs per user.
11150 Defaults to @samp{0}.
11153 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
11154 Specifies the maximum time a job may take to print before it is
11155 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
11157 Defaults to @samp{10800}.
11160 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
11161 Specifies the maximum size of the log files before they are rotated, in
11162 bytes. The value 0 disables log rotation.
11164 Defaults to @samp{1048576}.
11167 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
11168 Specifies the maximum amount of time to allow between files in a
11169 multiple file print job, in seconds.
11171 Defaults to @samp{300}.
11174 @deftypevr {@code{cups-configuration} parameter} string page-log-format
11175 Specifies the format of PageLog lines. Sequences beginning with percent
11176 (@samp{%}) characters are replaced with the corresponding information,
11177 while all other characters are copied literally. The following percent
11178 sequences are recognized:
11182 insert a single percent character
11185 insert the value of the specified IPP attribute
11188 insert the number of copies for the current page
11191 insert the current page number
11194 insert the current date and time in common log format
11200 insert the printer name
11203 insert the username
11206 A value of the empty string disables page logging. The string @code{%p
11207 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
11208 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
11211 Defaults to @samp{""}.
11214 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
11215 Passes the specified environment variable(s) to child processes; a list
11218 Defaults to @samp{()}.
11221 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
11222 Specifies named access control policies.
11224 Available @code{policy-configuration} fields are:
11226 @deftypevr {@code{policy-configuration} parameter} string name
11227 Name of the policy.
11230 @deftypevr {@code{policy-configuration} parameter} string job-private-access
11231 Specifies an access list for a job's private values. @code{@@ACL} maps
11232 to the printer's requesting-user-name-allowed or
11233 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11234 owner. @code{@@SYSTEM} maps to the groups listed for the
11235 @code{system-group} field of the @code{files-config} configuration,
11236 which is reified into the @code{cups-files.conf(5)} file. Other
11237 possible elements of the access list include specific user names, and
11238 @code{@@@var{group}} to indicate members of a specific group. The
11239 access list may also be simply @code{all} or @code{default}.
11241 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11244 @deftypevr {@code{policy-configuration} parameter} string job-private-values
11245 Specifies the list of job values to make private, or @code{all},
11246 @code{default}, or @code{none}.
11248 Defaults to @samp{"job-name job-originating-host-name
11249 job-originating-user-name phone"}.
11252 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
11253 Specifies an access list for a subscription's private values.
11254 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
11255 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
11256 owner. @code{@@SYSTEM} maps to the groups listed for the
11257 @code{system-group} field of the @code{files-config} configuration,
11258 which is reified into the @code{cups-files.conf(5)} file. Other
11259 possible elements of the access list include specific user names, and
11260 @code{@@@var{group}} to indicate members of a specific group. The
11261 access list may also be simply @code{all} or @code{default}.
11263 Defaults to @samp{"@@OWNER @@SYSTEM"}.
11266 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
11267 Specifies the list of job values to make private, or @code{all},
11268 @code{default}, or @code{none}.
11270 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
11271 notify-subscriber-user-name notify-user-data"}.
11274 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
11275 Access control by IPP operation.
11277 Defaults to @samp{()}.
11281 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
11282 Specifies whether job files (documents) are preserved after a job is
11283 printed. If a numeric value is specified, job files are preserved for
11284 the indicated number of seconds after printing. Otherwise a boolean
11285 value applies indefinitely.
11287 Defaults to @samp{86400}.
11290 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
11291 Specifies whether the job history is preserved after a job is printed.
11292 If a numeric value is specified, the job history is preserved for the
11293 indicated number of seconds after printing. If @code{#t}, the job
11294 history is preserved until the MaxJobs limit is reached.
11296 Defaults to @samp{#t}.
11299 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
11300 Specifies the amount of time to wait for job completion before
11301 restarting the scheduler.
11303 Defaults to @samp{30}.
11306 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11307 Specifies the maximum amount of memory to use when converting documents
11308 into bitmaps for a printer.
11310 Defaults to @samp{"128m"}.
11313 @deftypevr {@code{cups-configuration} parameter} string server-admin
11314 Specifies the email address of the server administrator.
11316 Defaults to @samp{"root@@localhost.localdomain"}.
11319 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11320 The ServerAlias directive is used for HTTP Host header validation when
11321 clients connect to the scheduler from external interfaces. Using the
11322 special name @code{*} can expose your system to known browser-based DNS
11323 rebinding attacks, even when accessing sites through a firewall. If the
11324 auto-discovery of alternate names does not work, we recommend listing
11325 each alternate name with a ServerAlias directive instead of using
11328 Defaults to @samp{*}.
11331 @deftypevr {@code{cups-configuration} parameter} string server-name
11332 Specifies the fully-qualified host name of the server.
11334 Defaults to @samp{"localhost"}.
11337 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11338 Specifies what information is included in the Server header of HTTP
11339 responses. @code{None} disables the Server header. @code{ProductOnly}
11340 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11341 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11342 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11343 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11344 2.0.0 (@var{uname}) IPP/2.0}.
11346 Defaults to @samp{Minimal}.
11349 @deftypevr {@code{cups-configuration} parameter} string set-env
11350 Set the specified environment variable to be passed to child processes.
11352 Defaults to @samp{"variable value"}.
11355 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11356 Listens on the specified interfaces for encrypted connections. Valid
11357 values are of the form @var{address}:@var{port}, where @var{address} is
11358 either an IPv6 address enclosed in brackets, an IPv4 address, or
11359 @code{*} to indicate all addresses.
11361 Defaults to @samp{()}.
11364 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11365 Sets encryption options. By default, CUPS only supports encryption
11366 using TLS v1.0 or higher using known secure cipher suites. The
11367 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11368 required for some older clients that do not implement newer ones. The
11369 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11370 older clients that do not support TLS v1.0.
11372 Defaults to @samp{()}.
11375 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11376 Specifies whether the scheduler requires clients to strictly adhere to
11377 the IPP specifications.
11379 Defaults to @samp{#f}.
11382 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11383 Specifies the HTTP request timeout, in seconds.
11385 Defaults to @samp{300}.
11389 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11390 Specifies whether the web interface is enabled.
11392 Defaults to @samp{#f}.
11395 At this point you're probably thinking ``oh dear, Guix manual, I like
11396 you but you can stop already with the configuration options''. Indeed.
11397 However, one more point: it could be that you have an existing
11398 @code{cupsd.conf} that you want to use. In that case, you can pass an
11399 @code{opaque-cups-configuration} as the configuration of a
11400 @code{cups-service-type}.
11402 Available @code{opaque-cups-configuration} fields are:
11404 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11408 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11409 The contents of the @code{cupsd.conf}, as a string.
11412 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11413 The contents of the @code{cups-files.conf} file, as a string.
11416 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11417 strings of the same name, you could instantiate a CUPS service like
11421 (service cups-service-type
11422 (opaque-cups-configuration
11423 (cupsd.conf cupsd.conf)
11424 (cups-files.conf cups-files.conf)))
11428 @node Desktop Services
11429 @subsubsection Desktop Services
11431 The @code{(gnu services desktop)} module provides services that are
11432 usually useful in the context of a ``desktop'' setup---that is, on a
11433 machine running a graphical display server, possibly with graphical user
11434 interfaces, etc. It also defines services that provide specific desktop
11435 environments like GNOME and XFCE.
11437 To simplify things, the module defines a variable containing the set of
11438 services that users typically expect on a machine with a graphical
11439 environment and networking:
11441 @defvr {Scheme Variable} %desktop-services
11442 This is a list of services that builds upon @var{%base-services} and
11443 adds or adjusts services for a typical ``desktop'' setup.
11445 In particular, it adds a graphical login manager (@pxref{X Window,
11446 @code{slim-service}}), screen lockers,
11447 a network management tool (@pxref{Networking
11448 Services, @code{wicd-service}}), energy and color management services,
11449 the @code{elogind} login and seat manager, the Polkit privilege service,
11450 the GeoClue location service, an NTP client (@pxref{Networking
11451 Services}), the Avahi daemon, and has the name service switch service
11452 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11456 The @var{%desktop-services} variable can be used as the @code{services}
11457 field of an @code{operating-system} declaration (@pxref{operating-system
11458 Reference, @code{services}}).
11460 Additionally, the @code{gnome-desktop-service} and
11461 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11462 system. To ``add GNOME'' means that system-level services like the
11463 backlight adjustment helpers and the power management utilities are
11464 added to the system, extending @code{polkit} and @code{dbus}
11465 appropriately, allowing GNOME to operate with elevated privileges on a
11466 limited number of special-purpose system interfaces. Additionally,
11467 adding a service made by @code{gnome-desktop-service} adds the GNOME
11468 metapackage to the system profile. Likewise, adding the XFCE service
11469 not only adds the @code{xfce} metapackage to the system profile, but it
11470 also gives the Thunar file manager the ability to open a ``root-mode''
11471 file management window, if the user authenticates using the
11472 administrator's password via the standard polkit graphical interface.
11474 @deffn {Scheme Procedure} gnome-desktop-service
11475 Return a service that adds the @code{gnome} package to the system
11476 profile, and extends polkit with the actions from
11477 @code{gnome-settings-daemon}.
11480 @deffn {Scheme Procedure} xfce-desktop-service
11481 Return a service that adds the @code{xfce} package to the system profile,
11482 and extends polkit with the ability for @code{thunar} to manipulate the
11483 file system as root from within a user session, after the user has
11484 authenticated with the administrator's password.
11487 Because the GNOME and XFCE desktop services pull in so many packages,
11488 the default @code{%desktop-services} variable doesn't include either of
11489 them by default. To add GNOME or XFCE, just @code{cons} them onto
11490 @code{%desktop-services} in the @code{services} field of your
11491 @code{operating-system}:
11494 (use-modules (gnu))
11495 (use-service-modules desktop)
11498 ;; cons* adds items to the list given as its last argument.
11499 (services (cons* (gnome-desktop-service)
11500 (xfce-desktop-service)
11501 %desktop-services))
11505 These desktop environments will then be available as options in the
11506 graphical login window.
11508 The actual service definitions included in @code{%desktop-services} and
11509 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11510 are described below.
11512 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11513 Return a service that runs the ``system bus'', using @var{dbus}, with
11514 support for @var{services}.
11516 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11517 facility. Its system bus is used to allow system services to communicate
11518 and to be notified of system-wide events.
11520 @var{services} must be a list of packages that provide an
11521 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11522 and policy files. For example, to allow avahi-daemon to use the system bus,
11523 @var{services} must be equal to @code{(list avahi)}.
11526 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11527 Return a service that runs the @code{elogind} login and
11528 seat management daemon. @uref{https://github.com/andywingo/elogind,
11529 Elogind} exposes a D-Bus interface that can be used to know which users
11530 are logged in, know what kind of sessions they have open, suspend the
11531 system, inhibit system suspend, reboot the system, and other tasks.
11533 Elogind handles most system-level power events for a computer, for
11534 example suspending the system when a lid is closed, or shutting it down
11535 when the power button is pressed.
11537 The @var{config} keyword argument specifies the configuration for
11538 elogind, and should be the result of an @code{(elogind-configuration
11539 (@var{parameter} @var{value})...)} invocation. Available parameters and
11540 their default values are:
11543 @item kill-user-processes?
11545 @item kill-only-users
11547 @item kill-exclude-users
11549 @item inhibit-delay-max-seconds
11551 @item handle-power-key
11553 @item handle-suspend-key
11555 @item handle-hibernate-key
11557 @item handle-lid-switch
11559 @item handle-lid-switch-docked
11561 @item power-key-ignore-inhibited?
11563 @item suspend-key-ignore-inhibited?
11565 @item hibernate-key-ignore-inhibited?
11567 @item lid-switch-ignore-inhibited?
11569 @item holdoff-timeout-seconds
11573 @item idle-action-seconds
11575 @item runtime-directory-size-percent
11577 @item runtime-directory-size
11581 @item suspend-state
11582 @code{("mem" "standby" "freeze")}
11585 @item hibernate-state
11587 @item hibernate-mode
11588 @code{("platform" "shutdown")}
11589 @item hybrid-sleep-state
11591 @item hybrid-sleep-mode
11592 @code{("suspend" "platform" "shutdown")}
11596 @deffn {Scheme Procedure} polkit-service @
11597 [#:polkit @var{polkit}]
11598 Return a service that runs the
11599 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11600 management service}, which allows system administrators to grant access to
11601 privileged operations in a structured way. By querying the Polkit service, a
11602 privileged system component can know when it should grant additional
11603 capabilities to ordinary users. For example, an ordinary user can be granted
11604 the capability to suspend the system if the user is logged in locally.
11607 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11608 [#:watts-up-pro? #f] @
11609 [#:poll-batteries? #t] @
11610 [#:ignore-lid? #f] @
11611 [#:use-percentage-for-policy? #f] @
11612 [#:percentage-low 10] @
11613 [#:percentage-critical 3] @
11614 [#:percentage-action 2] @
11615 [#:time-low 1200] @
11616 [#:time-critical 300] @
11617 [#:time-action 120] @
11618 [#:critical-power-action 'hybrid-sleep]
11619 Return a service that runs @uref{http://upower.freedesktop.org/,
11620 @command{upowerd}}, a system-wide monitor for power consumption and battery
11621 levels, with the given configuration settings. It implements the
11622 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11626 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11627 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11628 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11629 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11630 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11633 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11634 Return a service that runs @command{colord}, a system service with a D-Bus
11635 interface to manage the color profiles of input and output devices such as
11636 screens and scanners. It is notably used by the GNOME Color Manager graphical
11637 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11638 site} for more information.
11641 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11642 Return a configuration allowing an application to access GeoClue
11643 location data. @var{name} is the Desktop ID of the application, without
11644 the @code{.desktop} part. If @var{allowed?} is true, the application
11645 will have access to location information by default. The boolean
11646 @var{system?} value indicates whether an application is a system component
11647 or not. Finally @var{users} is a list of UIDs of all users for which
11648 this application is allowed location info access. An empty users list
11649 means that all users are allowed.
11652 @defvr {Scheme Variable} %standard-geoclue-applications
11653 The standard list of well-known GeoClue application configurations,
11654 granting authority to the GNOME date-and-time utility to ask for the
11655 current location in order to set the time zone, and allowing the
11656 IceCat and Epiphany web browsers to request location information.
11657 IceCat and Epiphany both query the user before allowing a web page to
11658 know the user's location.
11661 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11662 [#:whitelist '()] @
11663 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11664 [#:submit-data? #f]
11665 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11666 [#:submission-nick "geoclue"] @
11667 [#:applications %standard-geoclue-applications]
11668 Return a service that runs the GeoClue location service. This service
11669 provides a D-Bus interface to allow applications to request access to a
11670 user's physical location, and optionally to add information to online
11671 location databases. See
11672 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11673 web site} for more information.
11676 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11677 Return a service that runs the @command{bluetoothd} daemon, which manages
11678 all the Bluetooth devices and provides a number of D-Bus interfaces.
11680 Users need to be in the @code{lp} group to access the D-Bus service.
11683 @node Database Services
11684 @subsubsection Database Services
11688 The @code{(gnu services databases)} module provides the following services.
11690 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11691 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11692 [#:port 5432] [#:locale ``en_US.utf8'']
11693 Return a service that runs @var{postgresql}, the PostgreSQL database
11696 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11697 creates a database cluster with @var{locale} as the default
11698 locale, stored in @var{data-directory}. It then listens on @var{port}.
11701 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11702 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11705 The optional @var{config} argument specifies the configuration for
11706 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11709 @deftp {Data Type} mysql-configuration
11710 Data type representing the configuration of @var{mysql-service}.
11713 @item @code{mysql} (default: @var{mariadb})
11714 Package object of the MySQL database server, can be either @var{mariadb}
11717 For MySQL, a temporary root password will be displayed at activation time.
11718 For MariaDB, the root password is empty.
11720 @item @code{port} (default: @code{3306})
11721 TCP port on which the database server listens for incoming connections.
11725 @defvr {Scheme Variable} redis-service-type
11726 This is the service type for the @uref{https://redis.io/, Redis}
11727 key/value store, whose value is a @code{redis-configuration} object.
11730 @deftp {Data Type} redis-configuration
11731 Data type representing the configuration of redis.
11734 @item @code{redis} (default: @code{redis})
11735 The Redis package to use.
11737 @item @code{bind} (default: @code{"127.0.0.1"})
11738 Network interface on which to listen.
11740 @item @code{port} (default: @code{6379})
11741 Port on which to accept connections on, a value of 0 will disable
11742 listening on a TCP socket.
11744 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11745 Directory in which to store the database and related files.
11749 @node Mail Services
11750 @subsubsection Mail Services
11754 The @code{(gnu services mail)} module provides Guix service definitions
11755 for email services: IMAP, POP3, and LMTP servers, as well as mail
11756 transport agents (MTAs). Lots of acronyms! These services are detailed
11757 in the subsections below.
11759 @subsubheading Dovecot Service
11761 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11762 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11765 By default, Dovecot does not need much configuration; the default
11766 configuration object created by @code{(dovecot-configuration)} will
11767 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11768 certificate will be generated for TLS-protected connections, though
11769 Dovecot will also listen on cleartext ports by default. There are a
11770 number of options, though, which mail administrators might need to change,
11771 and as is the case with other services, Guix allows the system
11772 administrator to specify these parameters via a uniform Scheme interface.
11774 For example, to specify that mail is located at @code{maildir~/.mail},
11775 one would instantiate the Dovecot service like this:
11778 (dovecot-service #:config
11779 (dovecot-configuration
11780 (mail-location "maildir:~/.mail")))
11783 The available configuration parameters follow. Each parameter
11784 definition is preceded by its type; for example, @samp{string-list foo}
11785 indicates that the @code{foo} parameter should be specified as a list of
11786 strings. There is also a way to specify the configuration as a string,
11787 if you have an old @code{dovecot.conf} file that you want to port over
11788 from some other system; see the end for more details.
11790 @c The following documentation was initially generated by
11791 @c (generate-documentation) in (gnu services mail). Manually maintained
11792 @c documentation is better, so we shouldn't hesitate to edit below as
11793 @c needed. However if the change you want to make to this documentation
11794 @c can be done in an automated way, it's probably easier to change
11795 @c (generate-documentation) than to make it below and have to deal with
11796 @c the churn as dovecot updates.
11798 Available @code{dovecot-configuration} fields are:
11800 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11801 The dovecot package.
11804 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11805 A list of IPs or hosts where to listen for connections. @samp{*}
11806 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11807 interfaces. If you want to specify non-default ports or anything more
11808 complex, customize the address and port fields of the
11809 @samp{inet-listener} of the specific services you are interested in.
11812 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11813 List of protocols we want to serve. Available protocols include
11814 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11816 Available @code{protocol-configuration} fields are:
11818 @deftypevr {@code{protocol-configuration} parameter} string name
11819 The name of the protocol.
11822 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11823 UNIX socket path to the master authentication server to find users.
11824 This is used by imap (for shared users) and lda.
11825 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11828 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11829 Space separated list of plugins to load.
11832 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11833 Maximum number of IMAP connections allowed for a user from each IP
11834 address. NOTE: The username is compared case-sensitively.
11835 Defaults to @samp{10}.
11840 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11841 List of services to enable. Available services include @samp{imap},
11842 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11845 Available @code{service-configuration} fields are:
11847 @deftypevr {@code{service-configuration} parameter} string kind
11848 The service kind. Valid values include @code{director},
11849 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11850 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11851 @code{tcpwrap}, @code{quota-warning}, or anything else.
11854 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11855 Listeners for the service. A listener is either a
11856 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11857 an @code{inet-listener-configuration}.
11858 Defaults to @samp{()}.
11860 Available @code{unix-listener-configuration} fields are:
11862 @deftypevr {@code{unix-listener-configuration} parameter} string path
11863 Path to the file, relative to @code{base-dir} field. This is also used as
11867 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11868 The access mode for the socket.
11869 Defaults to @samp{"0600"}.
11872 @deftypevr {@code{unix-listener-configuration} parameter} string user
11873 The user to own the socket.
11874 Defaults to @samp{""}.
11877 @deftypevr {@code{unix-listener-configuration} parameter} string group
11878 The group to own the socket.
11879 Defaults to @samp{""}.
11883 Available @code{fifo-listener-configuration} fields are:
11885 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11886 Path to the file, relative to @code{base-dir} field. This is also used as
11890 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11891 The access mode for the socket.
11892 Defaults to @samp{"0600"}.
11895 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11896 The user to own the socket.
11897 Defaults to @samp{""}.
11900 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11901 The group to own the socket.
11902 Defaults to @samp{""}.
11906 Available @code{inet-listener-configuration} fields are:
11908 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11909 The protocol to listen for.
11912 @deftypevr {@code{inet-listener-configuration} parameter} string address
11913 The address on which to listen, or empty for all addresses.
11914 Defaults to @samp{""}.
11917 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11918 The port on which to listen.
11921 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11922 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11924 Defaults to @samp{#t}.
11929 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11930 Number of connections to handle before starting a new process.
11931 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11932 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11933 Defaults to @samp{1}.
11936 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11937 Number of processes to always keep waiting for more connections.
11938 Defaults to @samp{0}.
11941 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11942 If you set @samp{service-count 0}, you probably need to grow
11944 Defaults to @samp{256000000}.
11949 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11950 Dict configuration, as created by the @code{dict-configuration}
11953 Available @code{dict-configuration} fields are:
11955 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11956 A list of key-value pairs that this dict should hold.
11957 Defaults to @samp{()}.
11962 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11963 A list of passdb configurations, each one created by the
11964 @code{passdb-configuration} constructor.
11966 Available @code{passdb-configuration} fields are:
11968 @deftypevr {@code{passdb-configuration} parameter} string driver
11969 The driver that the passdb should use. Valid values include
11970 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11972 Defaults to @samp{"pam"}.
11975 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11976 Space separated list of arguments to the passdb driver.
11977 Defaults to @samp{""}.
11982 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11983 List of userdb configurations, each one created by the
11984 @code{userdb-configuration} constructor.
11986 Available @code{userdb-configuration} fields are:
11988 @deftypevr {@code{userdb-configuration} parameter} string driver
11989 The driver that the userdb should use. Valid values include
11990 @samp{passwd} and @samp{static}.
11991 Defaults to @samp{"passwd"}.
11994 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11995 Space separated list of arguments to the userdb driver.
11996 Defaults to @samp{""}.
11999 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
12000 Override fields from passwd.
12001 Defaults to @samp{()}.
12006 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
12007 Plug-in configuration, created by the @code{plugin-configuration}
12011 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
12012 List of namespaces. Each item in the list is created by the
12013 @code{namespace-configuration} constructor.
12015 Available @code{namespace-configuration} fields are:
12017 @deftypevr {@code{namespace-configuration} parameter} string name
12018 Name for this namespace.
12021 @deftypevr {@code{namespace-configuration} parameter} string type
12022 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
12023 Defaults to @samp{"private"}.
12026 @deftypevr {@code{namespace-configuration} parameter} string separator
12027 Hierarchy separator to use. You should use the same separator for
12028 all namespaces or some clients get confused. @samp{/} is usually a good
12029 one. The default however depends on the underlying mail storage
12031 Defaults to @samp{""}.
12034 @deftypevr {@code{namespace-configuration} parameter} string prefix
12035 Prefix required to access this namespace. This needs to be
12036 different for all namespaces. For example @samp{Public/}.
12037 Defaults to @samp{""}.
12040 @deftypevr {@code{namespace-configuration} parameter} string location
12041 Physical location of the mailbox. This is in the same format as
12042 mail_location, which is also the default for it.
12043 Defaults to @samp{""}.
12046 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
12047 There can be only one INBOX, and this setting defines which
12049 Defaults to @samp{#f}.
12052 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
12053 If namespace is hidden, it's not advertised to clients via NAMESPACE
12054 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
12055 useful when converting from another server with different namespaces
12056 which you want to deprecate but still keep working. For example you can
12057 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
12059 Defaults to @samp{#f}.
12062 @deftypevr {@code{namespace-configuration} parameter} boolean list?
12063 Show the mailboxes under this namespace with the LIST command. This
12064 makes the namespace visible for clients that do not support the NAMESPACE
12065 extension. The special @code{children} value lists child mailboxes, but
12066 hides the namespace prefix.
12067 Defaults to @samp{#t}.
12070 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
12071 Namespace handles its own subscriptions. If set to @code{#f}, the
12072 parent namespace handles them. The empty prefix should always have this
12074 Defaults to @samp{#t}.
12077 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
12078 List of predefined mailboxes in this namespace.
12079 Defaults to @samp{()}.
12081 Available @code{mailbox-configuration} fields are:
12083 @deftypevr {@code{mailbox-configuration} parameter} string name
12084 Name for this mailbox.
12087 @deftypevr {@code{mailbox-configuration} parameter} string auto
12088 @samp{create} will automatically create this mailbox.
12089 @samp{subscribe} will both create and subscribe to the mailbox.
12090 Defaults to @samp{"no"}.
12093 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
12094 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
12095 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
12096 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
12097 Defaults to @samp{()}.
12104 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
12105 Base directory where to store runtime data.
12106 Defaults to @samp{"/var/run/dovecot/"}.
12109 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
12110 Greeting message for clients.
12111 Defaults to @samp{"Dovecot ready."}.
12114 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
12115 List of trusted network ranges. Connections from these IPs are
12116 allowed to override their IP addresses and ports (for logging and for
12117 authentication checks). @samp{disable-plaintext-auth} is also ignored
12118 for these networks. Typically you would specify your IMAP proxy servers
12120 Defaults to @samp{()}.
12123 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
12124 List of login access check sockets (e.g. tcpwrap).
12125 Defaults to @samp{()}.
12128 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
12129 Show more verbose process titles (in ps). Currently shows user name
12130 and IP address. Useful for seeing who is actually using the IMAP
12131 processes (e.g. shared mailboxes or if the same uid is used for multiple
12133 Defaults to @samp{#f}.
12136 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
12137 Should all processes be killed when Dovecot master process shuts down.
12138 Setting this to @code{#f} means that Dovecot can be upgraded without
12139 forcing existing client connections to close (although that could also
12140 be a problem if the upgrade is e.g. due to a security fix).
12141 Defaults to @samp{#t}.
12144 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
12145 If non-zero, run mail commands via this many connections to doveadm
12146 server, instead of running them directly in the same process.
12147 Defaults to @samp{0}.
12150 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
12151 UNIX socket or host:port used for connecting to doveadm server.
12152 Defaults to @samp{"doveadm-server"}.
12155 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
12156 List of environment variables that are preserved on Dovecot startup
12157 and passed down to all of its child processes. You can also give
12158 key=value pairs to always set specific settings.
12161 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
12162 Disable LOGIN command and all other plaintext authentications unless
12163 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
12164 matches the local IP (i.e. you're connecting from the same computer),
12165 the connection is considered secure and plaintext authentication is
12166 allowed. See also ssl=required setting.
12167 Defaults to @samp{#t}.
12170 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
12171 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
12172 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
12173 for caching to be used.
12174 Defaults to @samp{0}.
12177 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
12178 Time to live for cached data. After TTL expires the cached record
12179 is no longer used, *except* if the main database lookup returns internal
12180 failure. We also try to handle password changes automatically: If
12181 user's previous authentication was successful, but this one wasn't, the
12182 cache isn't used. For now this works only with plaintext
12184 Defaults to @samp{"1 hour"}.
12187 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
12188 TTL for negative hits (user not found, password mismatch).
12189 0 disables caching them completely.
12190 Defaults to @samp{"1 hour"}.
12193 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
12194 List of realms for SASL authentication mechanisms that need them.
12195 You can leave it empty if you don't want to support multiple realms.
12196 Many clients simply use the first one listed here, so keep the default
12198 Defaults to @samp{()}.
12201 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
12202 Default realm/domain to use if none was specified. This is used for
12203 both SASL realms and appending @@domain to username in plaintext
12205 Defaults to @samp{""}.
12208 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
12209 List of allowed characters in username. If the user-given username
12210 contains a character not listed in here, the login automatically fails.
12211 This is just an extra check to make sure user can't exploit any
12212 potential quote escaping vulnerabilities with SQL/LDAP databases. If
12213 you want to allow all characters, set this value to empty.
12214 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
12217 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
12218 Username character translations before it's looked up from
12219 databases. The value contains series of from -> to characters. For
12220 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
12221 translated to @samp{@@}.
12222 Defaults to @samp{""}.
12225 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
12226 Username formatting before it's looked up from databases. You can
12227 use the standard variables here, e.g. %Lu would lowercase the username,
12228 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
12229 change the @samp{@@} into @samp{-AT-}. This translation is done after
12230 @samp{auth-username-translation} changes.
12231 Defaults to @samp{"%Lu"}.
12234 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
12235 If you want to allow master users to log in by specifying the master
12236 username within the normal username string (i.e. not using SASL
12237 mechanism's support for it), you can specify the separator character
12238 here. The format is then <username><separator><master username>.
12239 UW-IMAP uses @samp{*} as the separator, so that could be a good
12241 Defaults to @samp{""}.
12244 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
12245 Username to use for users logging in with ANONYMOUS SASL
12247 Defaults to @samp{"anonymous"}.
12250 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
12251 Maximum number of dovecot-auth worker processes. They're used to
12252 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
12253 They're automatically created and destroyed as needed.
12254 Defaults to @samp{30}.
12257 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
12258 Host name to use in GSSAPI principal names. The default is to use
12259 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
12260 allow all keytab entries.
12261 Defaults to @samp{""}.
12264 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
12265 Kerberos keytab to use for the GSSAPI mechanism. Will use the
12266 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
12267 need to change the auth service to run as root to be able to read this
12269 Defaults to @samp{""}.
12272 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
12273 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
12274 and @samp{ntlm-auth} helper.
12275 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
12276 Defaults to @samp{#f}.
12279 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
12280 Path for Samba's @samp{ntlm-auth} helper binary.
12281 Defaults to @samp{"/usr/bin/ntlm_auth"}.
12284 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
12285 Time to delay before replying to failed authentications.
12286 Defaults to @samp{"2 secs"}.
12289 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
12290 Require a valid SSL client certificate or the authentication
12292 Defaults to @samp{#f}.
12295 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
12296 Take the username from client's SSL certificate, using
12297 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
12299 Defaults to @samp{#f}.
12302 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
12303 List of wanted authentication mechanisms. Supported mechanisms are:
12304 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
12305 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12306 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12307 @samp{disable-plaintext-auth} setting.
12310 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12311 List of IPs or hostnames to all director servers, including ourself.
12312 Ports can be specified as ip:port. The default port is the same as what
12313 director service's @samp{inet-listener} is using.
12314 Defaults to @samp{()}.
12317 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12318 List of IPs or hostnames to all backend mail servers. Ranges are
12319 allowed too, like 10.0.0.10-10.0.0.30.
12320 Defaults to @samp{()}.
12323 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12324 How long to redirect users to a specific server after it no longer
12325 has any connections.
12326 Defaults to @samp{"15 min"}.
12329 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12330 TCP/IP port that accepts doveadm connections (instead of director
12331 connections) If you enable this, you'll also need to add
12332 @samp{inet-listener} for the port.
12333 Defaults to @samp{0}.
12336 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12337 How the username is translated before being hashed. Useful values
12338 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12339 are shared within domain.
12340 Defaults to @samp{"%Lu"}.
12343 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12344 Log file to use for error messages. @samp{syslog} logs to syslog,
12345 @samp{/dev/stderr} logs to stderr.
12346 Defaults to @samp{"syslog"}.
12349 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12350 Log file to use for informational messages. Defaults to
12352 Defaults to @samp{""}.
12355 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12356 Log file to use for debug messages. Defaults to
12357 @samp{info-log-path}.
12358 Defaults to @samp{""}.
12361 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12362 Syslog facility to use if you're logging to syslog. Usually if you
12363 don't want to use @samp{mail}, you'll use local0..local7. Also other
12364 standard facilities are supported.
12365 Defaults to @samp{"mail"}.
12368 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12369 Log unsuccessful authentication attempts and the reasons why they
12371 Defaults to @samp{#f}.
12374 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12375 In case of password mismatches, log the attempted password. Valid
12376 values are no, plain and sha1. sha1 can be useful for detecting brute
12377 force password attempts vs. user simply trying the same password over
12378 and over again. You can also truncate the value to n chars by appending
12379 ":n" (e.g. sha1:6).
12380 Defaults to @samp{#f}.
12383 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12384 Even more verbose logging for debugging purposes. Shows for example
12386 Defaults to @samp{#f}.
12389 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12390 In case of password mismatches, log the passwords and used scheme so
12391 the problem can be debugged. Enabling this also enables
12393 Defaults to @samp{#f}.
12396 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12397 Enable mail process debugging. This can help you figure out why
12398 Dovecot isn't finding your mails.
12399 Defaults to @samp{#f}.
12402 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12403 Show protocol level SSL errors.
12404 Defaults to @samp{#f}.
12407 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12408 Prefix for each line written to log file. % codes are in
12409 strftime(3) format.
12410 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12413 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12414 List of elements we want to log. The elements which have a
12415 non-empty variable value are joined together to form a comma-separated
12419 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12420 Login log format. %s contains @samp{login-log-format-elements}
12421 string, %$ contains the data we want to log.
12422 Defaults to @samp{"%$: %s"}.
12425 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12426 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12427 of possible variables you can use.
12428 Defaults to @samp{"\"%s(%u): \""}.
12431 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12432 Format to use for logging mail deliveries. You can use variables:
12435 Delivery status message (e.g. @samp{saved to INBOX})
12447 Defaults to @samp{"msgid=%m: %$"}.
12450 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12451 Location for users' mailboxes. The default is empty, which means
12452 that Dovecot tries to find the mailboxes automatically. This won't work
12453 if the user doesn't yet have any mail, so you should explicitly tell
12454 Dovecot the full location.
12456 If you're using mbox, giving a path to the INBOX
12457 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12458 where the other mailboxes are kept. This is called the "root mail
12459 directory", and it must be the first path given in the
12460 @samp{mail-location} setting.
12462 There are a few special variables you can use, eg.:
12468 user part in user@@domain, same as %u if there's no domain
12470 domain part in user@@domain, empty if there's no domain
12475 See doc/wiki/Variables.txt for full list. Some examples:
12477 @item maildir:~/Maildir
12478 @item mbox:~/mail:INBOX=/var/mail/%u
12479 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12481 Defaults to @samp{""}.
12484 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12485 System user and group used to access mails. If you use multiple,
12486 userdb can override these by returning uid or gid fields. You can use
12487 either numbers or names. <doc/wiki/UserIds.txt>.
12488 Defaults to @samp{""}.
12491 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12493 Defaults to @samp{""}.
12496 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12497 Group to enable temporarily for privileged operations. Currently
12498 this is used only with INBOX when either its initial creation or
12499 dotlocking fails. Typically this is set to "mail" to give access to
12501 Defaults to @samp{""}.
12504 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12505 Grant access to these supplementary groups for mail processes.
12506 Typically these are used to set up access to shared mailboxes. Note
12507 that it may be dangerous to set these if users can create
12508 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12509 could allow a user to delete others' mailboxes, or ln -s
12510 /secret/shared/box ~/mail/mybox would allow reading it).
12511 Defaults to @samp{""}.
12514 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12515 Allow full file system access to clients. There's no access checks
12516 other than what the operating system does for the active UID/GID. It
12517 works with both maildir and mboxes, allowing you to prefix mailboxes
12518 names with e.g. /path/ or ~user/.
12519 Defaults to @samp{#f}.
12522 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12523 Don't use mmap() at all. This is required if you store indexes to
12524 shared file systems (NFS or clustered file system).
12525 Defaults to @samp{#f}.
12528 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12529 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12530 supports @samp{O_EXCL} since version 3, so this should be safe to use
12531 nowadays by default.
12532 Defaults to @samp{#t}.
12535 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12536 When to use fsync() or fdatasync() calls:
12539 Whenever necessary to avoid losing important data
12541 Useful with e.g. NFS when write()s are delayed
12543 Never use it (best performance, but crashes can lose data).
12545 Defaults to @samp{"optimized"}.
12548 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12549 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12550 NFS caches whenever needed. If you're using only a single mail server
12552 Defaults to @samp{#f}.
12555 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12556 Mail index files also exist in NFS. Setting this to yes requires
12557 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12558 Defaults to @samp{#f}.
12561 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12562 Locking method for index files. Alternatives are fcntl, flock and
12563 dotlock. Dotlocking uses some tricks which may create more disk I/O
12564 than other locking methods. NFS users: flock doesn't work, remember to
12565 change @samp{mmap-disable}.
12566 Defaults to @samp{"fcntl"}.
12569 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12570 Directory in which LDA/LMTP temporarily stores incoming mails >128
12572 Defaults to @samp{"/tmp"}.
12575 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12576 Valid UID range for users. This is mostly to make sure that users can't
12577 log in as daemons or other system users. Note that denying root logins is
12578 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12580 Defaults to @samp{500}.
12583 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12585 Defaults to @samp{0}.
12588 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12589 Valid GID range for users. Users having non-valid GID as primary group ID
12590 aren't allowed to log in. If user belongs to supplementary groups with
12591 non-valid GIDs, those groups are not set.
12592 Defaults to @samp{1}.
12595 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12597 Defaults to @samp{0}.
12600 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12601 Maximum allowed length for mail keyword name. It's only forced when
12602 trying to create new keywords.
12603 Defaults to @samp{50}.
12606 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12607 List of directories under which chrooting is allowed for mail
12608 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12609 too). This setting doesn't affect @samp{login-chroot}
12610 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12611 "/./" in home dirs are ignored. WARNING: Never add directories here
12612 which local users can modify, that may lead to root exploit. Usually
12613 this should be done only if you don't allow shell access for users.
12614 <doc/wiki/Chrooting.txt>.
12615 Defaults to @samp{()}.
12618 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12619 Default chroot directory for mail processes. This can be overridden
12620 for specific users in user database by giving /./ in user's home
12621 directory (e.g. /home/./user chroots into /home). Note that usually
12622 there is no real need to do chrooting, Dovecot doesn't allow users to
12623 access files outside their mail directory anyway. If your home
12624 directories are prefixed with the chroot directory, append "/." to
12625 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12626 Defaults to @samp{""}.
12629 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12630 UNIX socket path to master authentication server to find users.
12631 This is used by imap (for shared users) and lda.
12632 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12635 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12636 Directory where to look up mail plugins.
12637 Defaults to @samp{"/usr/lib/dovecot"}.
12640 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12641 List of plugins to load for all services. Plugins specific to IMAP,
12642 LDA, etc. are added to this list in their own .conf files.
12643 Defaults to @samp{()}.
12646 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12647 The minimum number of mails in a mailbox before updates are done to
12648 cache file. This allows optimizing Dovecot's behavior to do less disk
12649 writes at the cost of more disk reads.
12650 Defaults to @samp{0}.
12653 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12654 When IDLE command is running, mailbox is checked once in a while to
12655 see if there are any new mails or other changes. This setting defines
12656 the minimum time to wait between those checks. Dovecot can also use
12657 dnotify, inotify and kqueue to find out immediately when changes
12659 Defaults to @samp{"30 secs"}.
12662 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12663 Save mails with CR+LF instead of plain LF. This makes sending those
12664 mails take less CPU, especially with sendfile() syscall with Linux and
12665 FreeBSD. But it also creates a bit more disk I/O which may just make it
12666 slower. Also note that if other software reads the mboxes/maildirs,
12667 they may handle the extra CRs wrong and cause problems.
12668 Defaults to @samp{#f}.
12671 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12672 By default LIST command returns all entries in maildir beginning
12673 with a dot. Enabling this option makes Dovecot return only entries
12674 which are directories. This is done by stat()ing each entry, so it
12675 causes more disk I/O.
12676 (For systems setting struct @samp{dirent->d_type} this check is free
12677 and it's done always regardless of this setting).
12678 Defaults to @samp{#f}.
12681 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12682 When copying a message, do it with hard links whenever possible.
12683 This makes the performance much better, and it's unlikely to have any
12685 Defaults to @samp{#t}.
12688 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12689 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12690 directory only when its mtime changes unexpectedly or when we can't find
12691 the mail otherwise.
12692 Defaults to @samp{#f}.
12695 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12696 Which locking methods to use for locking mbox. There are four
12701 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12702 solution. If you want to use /var/mail/ like directory, the users will
12703 need write access to that directory.
12705 Same as dotlock, but if it fails because of permissions or because there
12706 isn't enough disk space, just skip it.
12708 Use this if possible. Works with NFS too if lockd is used.
12710 May not exist in all systems. Doesn't work with NFS.
12712 May not exist in all systems. Doesn't work with NFS.
12715 You can use multiple locking methods; if you do the order they're declared
12716 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12717 locking methods as well. Some operating systems don't allow using some of
12718 them simultaneously.
12721 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12725 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12726 Maximum time to wait for lock (all of them) before aborting.
12727 Defaults to @samp{"5 mins"}.
12730 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12731 If dotlock exists but the mailbox isn't modified in any way,
12732 override the lock file after this much time.
12733 Defaults to @samp{"2 mins"}.
12736 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12737 When mbox changes unexpectedly we have to fully read it to find out
12738 what changed. If the mbox is large this can take a long time. Since
12739 the change is usually just a newly appended mail, it'd be faster to
12740 simply read the new mails. If this setting is enabled, Dovecot does
12741 this but still safely fallbacks to re-reading the whole mbox file
12742 whenever something in mbox isn't how it's expected to be. The only real
12743 downside to this setting is that if some other MUA changes message
12744 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12745 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12746 Defaults to @samp{#t}.
12749 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12750 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12751 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12752 @samp{mbox-dirty-syncs} is ignored.
12753 Defaults to @samp{#f}.
12756 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12757 Delay writing mbox headers until doing a full write sync (EXPUNGE
12758 and CHECK commands and when closing the mailbox). This is especially
12759 useful for POP3 where clients often delete all mails. The downside is
12760 that our changes aren't immediately visible to other MUAs.
12761 Defaults to @samp{#t}.
12764 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12765 If mbox size is smaller than this (e.g. 100k), don't write index
12766 files. If an index file already exists it's still read, just not
12768 Defaults to @samp{0}.
12771 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12772 Maximum dbox file size until it's rotated.
12773 Defaults to @samp{2000000}.
12776 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12777 Maximum dbox file age until it's rotated. Typically in days. Day
12778 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12780 Defaults to @samp{"1d"}.
12783 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12784 When creating new mdbox files, immediately preallocate their size to
12785 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12786 with some file systems (ext4, xfs).
12787 Defaults to @samp{#f}.
12790 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12791 sdbox and mdbox support saving mail attachments to external files,
12792 which also allows single instance storage for them. Other backends
12793 don't support this for now.
12795 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12797 Directory root where to store mail attachments. Disabled, if empty.
12798 Defaults to @samp{""}.
12801 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12802 Attachments smaller than this aren't saved externally. It's also
12803 possible to write a plugin to disable saving specific attachments
12805 Defaults to @samp{128000}.
12808 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12809 File system backend to use for saving attachments:
12812 No SiS done by Dovecot (but this might help FS's own deduplication)
12814 SiS with immediate byte-by-byte comparison during saving
12815 @item sis-queue posix
12816 SiS with delayed comparison and deduplication.
12818 Defaults to @samp{"sis posix"}.
12821 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12822 Hash format to use in attachment filenames. You can add any text and
12823 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12824 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12825 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12826 Defaults to @samp{"%@{sha1@}"}.
12829 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12831 Defaults to @samp{100}.
12834 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12836 Defaults to @samp{1000}.
12839 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12840 Default VSZ (virtual memory size) limit for service processes.
12841 This is mainly intended to catch and kill processes that leak memory
12842 before they eat up everything.
12843 Defaults to @samp{256000000}.
12846 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12847 Login user is internally used by login processes. This is the most
12848 untrusted user in Dovecot system. It shouldn't have access to anything
12850 Defaults to @samp{"dovenull"}.
12853 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12854 Internal user is used by unprivileged processes. It should be
12855 separate from login user, so that login processes can't disturb other
12857 Defaults to @samp{"dovecot"}.
12860 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12861 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12862 Defaults to @samp{"required"}.
12865 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12866 PEM encoded X.509 SSL/TLS certificate (public key).
12867 Defaults to @samp{"</etc/dovecot/default.pem"}.
12870 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12871 PEM encoded SSL/TLS private key. The key is opened before
12872 dropping root privileges, so keep the key file unreadable by anyone but
12874 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12877 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12878 If key file is password protected, give the password here.
12879 Alternatively give it when starting dovecot with -p parameter. Since
12880 this file is often world-readable, you may want to place this setting
12881 instead to a different.
12882 Defaults to @samp{""}.
12885 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12886 PEM encoded trusted certificate authority. Set this only if you
12887 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12888 contain the CA certificate(s) followed by the matching
12889 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12890 Defaults to @samp{""}.
12893 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12894 Require that CRL check succeeds for client certificates.
12895 Defaults to @samp{#t}.
12898 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12899 Request client to send a certificate. If you also want to require
12900 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12901 Defaults to @samp{#f}.
12904 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12905 Which field from certificate to use for username. commonName and
12906 x500UniqueIdentifier are the usual choices. You'll also need to set
12907 @samp{auth-ssl-username-from-cert? #t}.
12908 Defaults to @samp{"commonName"}.
12911 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12912 How often to regenerate the SSL parameters file. Generation is
12913 quite CPU intensive operation. The value is in hours, 0 disables
12914 regeneration entirely.
12915 Defaults to @samp{168}.
12918 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12919 SSL protocols to use.
12920 Defaults to @samp{"!SSLv2"}.
12923 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12924 SSL ciphers to use.
12925 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12928 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12929 SSL crypto device to use, for valid values run "openssl engine".
12930 Defaults to @samp{""}.
12933 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12934 Address to use when sending rejection mails.
12935 %d expands to recipient domain.
12936 Defaults to @samp{"postmaster@@%d"}.
12939 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12940 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12941 and in LMTP replies. Default is the system's real hostname@@domain.
12942 Defaults to @samp{""}.
12945 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12946 If user is over quota, return with temporary failure instead of
12948 Defaults to @samp{#f}.
12951 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12952 Binary to use for sending mails.
12953 Defaults to @samp{"/usr/sbin/sendmail"}.
12956 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12957 If non-empty, send mails via this SMTP host[:port] instead of
12959 Defaults to @samp{""}.
12962 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12963 Subject: header to use for rejection mails. You can use the same
12964 variables as for @samp{rejection-reason} below.
12965 Defaults to @samp{"Rejected: %s"}.
12968 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12969 Human readable error message for rejection mails. You can use
12982 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12985 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12986 Delimiter character between local-part and detail in email
12988 Defaults to @samp{"+"}.
12991 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12992 Header where the original recipient address (SMTP's RCPT TO:
12993 address) is taken from if not available elsewhere. With dovecot-lda -a
12994 parameter overrides this. A commonly used header for this is
12996 Defaults to @samp{""}.
12999 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
13000 Should saving a mail to a nonexistent mailbox automatically create
13002 Defaults to @samp{#f}.
13005 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
13006 Should automatically created mailboxes be also automatically
13008 Defaults to @samp{#f}.
13011 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
13012 Maximum IMAP command line length. Some clients generate very long
13013 command lines with huge mailboxes, so you may need to raise this if you
13014 get "Too long argument" or "IMAP command line too large" errors
13016 Defaults to @samp{64000}.
13019 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
13020 IMAP logout format string:
13023 total number of bytes read from client
13025 total number of bytes sent to client.
13027 Defaults to @samp{"in=%i out=%o"}.
13030 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
13031 Override the IMAP CAPABILITY response. If the value begins with '+',
13032 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
13033 Defaults to @samp{""}.
13036 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
13037 How long to wait between "OK Still here" notifications when client
13039 Defaults to @samp{"2 mins"}.
13042 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
13043 ID field names and values to send to clients. Using * as the value
13044 makes Dovecot use the default value. The following fields have default
13045 values currently: name, version, os, os-version, support-url,
13047 Defaults to @samp{""}.
13050 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
13051 ID fields sent by client to log. * means everything.
13052 Defaults to @samp{""}.
13055 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
13056 Workarounds for various client bugs:
13059 @item delay-newmail
13060 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
13061 CHECK commands. Some clients ignore them otherwise, for example OSX
13062 Mail (<v2.1). Outlook Express breaks more badly though, without this it
13063 may show user "Message no longer in server" errors. Note that OE6
13064 still breaks even with this workaround if synchronization is set to
13067 @item tb-extra-mailbox-sep
13068 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
13069 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
13070 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
13072 @item tb-lsub-flags
13073 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
13074 This makes Thunderbird realize they aren't selectable and show them
13075 greyed out, instead of only later giving "not selectable" popup error.
13077 Defaults to @samp{()}.
13080 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
13081 Host allowed in URLAUTH URLs sent by client. "*" allows all.
13082 Defaults to @samp{""}.
13086 Whew! Lots of configuration options. The nice thing about it though is
13087 that GuixSD has a complete interface to Dovecot's configuration
13088 language. This allows not only a nice way to declare configurations,
13089 but also offers reflective capabilities as well: users can write code to
13090 inspect and transform configurations from within Scheme.
13092 However, it could be that you just want to get a @code{dovecot.conf} up
13093 and running. In that case, you can pass an
13094 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
13095 @code{dovecot-service}. As its name indicates, an opaque configuration
13096 does not have easy reflective capabilities.
13098 Available @code{opaque-dovecot-configuration} fields are:
13100 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
13101 The dovecot package.
13104 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
13105 The contents of the @code{dovecot.conf}, as a string.
13108 For example, if your @code{dovecot.conf} is just the empty string, you
13109 could instantiate a dovecot service like this:
13112 (dovecot-service #:config
13113 (opaque-dovecot-configuration
13117 @subsubheading OpenSMTPD Service
13119 @deffn {Scheme Variable} opensmtpd-service-type
13120 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
13121 service, whose value should be an @code{opensmtpd-configuration} object
13122 as in this example:
13125 (service opensmtpd-service-type
13126 (opensmtpd-configuration
13127 (config-file (local-file "./my-smtpd.conf"))))
13131 @deftp {Data Type} opensmtpd-configuration
13132 Data type representing the configuration of opensmtpd.
13135 @item @code{package} (default: @var{opensmtpd})
13136 Package object of the OpenSMTPD SMTP server.
13138 @item @code{config-file} (default: @var{%default-opensmtpd-file})
13139 File-like object of the OpenSMTPD configuration file to use. By default
13140 it listens on the loopback network interface, and allows for mail from
13141 users and daemons on the local machine, as well as permitting email to
13142 remote servers. Run @command{man smtpd.conf} for more information.
13147 @subsubheading Exim Service
13149 @cindex mail transfer agent (MTA)
13150 @cindex MTA (mail transfer agent)
13153 @deffn {Scheme Variable} exim-service-type
13154 This is the type of the @uref{https://exim.org, Exim} mail transfer
13155 agent (MTA), whose value should be an @code{exim-configuration} object
13156 as in this example:
13159 (service exim-service-type
13160 (exim-configuration
13161 (config-file (local-file "./my-exim.conf"))))
13165 In order to use an @code{exim-service-type} service you must also have a
13166 @code{mail-aliases-service-type} service present in your
13167 @code{operating-system} (even if it has no aliases).
13169 @deftp {Data Type} exim-configuration
13170 Data type representing the configuration of exim.
13173 @item @code{package} (default: @var{exim})
13174 Package object of the Exim server.
13176 @item @code{config-file} (default: @code{#f})
13177 File-like object of the Exim configuration file to use. If its value is
13178 @code{#f} then use the default configuration file from the package
13179 provided in @code{package}. The resulting configuration file is loaded
13180 after setting the @code{exim_user} and @code{exim_group} configuration
13186 @subsubheading Mail Aliases Service
13188 @cindex email aliases
13189 @cindex aliases, for email addresses
13191 @deffn {Scheme Variable} mail-aliases-service-type
13192 This is the type of the service which provides @code{/etc/aliases},
13193 specifying how to deliver mail to users on this system.
13196 (service mail-aliases-service-type
13197 '(("postmaster" "bob")
13198 ("bob" "bob@@example.com" "bob@@example2.com")))
13202 The configuration for a @code{mail-aliases-service-type} service is an
13203 association list denoting how to deliver mail that comes to this
13204 system. Each entry is of the form @code{(alias addresses ...)}, with
13205 @code{alias} specifying the local alias and @code{addresses} specifying
13206 where to deliver this user's mail.
13208 The aliases aren't required to exist as users on the local system. In
13209 the above example, there doesn't need to be a @code{postmaster} entry in
13210 the @code{operating-system}'s @code{user-accounts} in order to deliver
13211 the @code{postmaster} mail to @code{bob} (which subsequently would
13212 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
13214 @node Messaging Services
13215 @subsubsection Messaging Services
13220 The @code{(gnu services messaging)} module provides Guix service
13221 definitions for messaging services: currently only Prosody is supported.
13223 @subsubheading Prosody Service
13225 @deffn {Scheme Variable} prosody-service-type
13226 This is the type for the @uref{http://prosody.im, Prosody XMPP
13227 communication server}. Its value must be a @code{prosody-configuration}
13228 record as in this example:
13231 (service prosody-service-type
13232 (prosody-configuration
13233 (modules-enabled (cons "groups" %default-modules-enabled))
13236 (int-component-configuration
13237 (hostname "conference.example.net")
13239 (mod-muc (mod-muc-configuration)))))
13242 (virtualhost-configuration
13243 (domain "example.net"))))))
13246 See below for details about @code{prosody-configuration}.
13250 By default, Prosody does not need much configuration. Only one
13251 @code{virtualhosts} field is needed: it specifies the domain you wish
13254 Prosodyctl will help you generate X.509 certificates and keys:
13257 prosodyctl cert request example.net
13260 The available configuration parameters follow. Each parameter
13261 definition is preceded by its type; for example, @samp{string-list foo}
13262 indicates that the @code{foo} parameter should be specified as a list of
13263 strings. Types starting with @code{maybe-} denote parameters that won't
13264 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
13266 There is also a way to specify the configuration as a string, if you
13267 have an old @code{prosody.cfg.lua} file that you want to port over from
13268 some other system; see the end for more details.
13270 @c The following documentation was initially generated by
13271 @c (generate-documentation) in (gnu services messaging). Manually maintained
13272 @c documentation is better, so we shouldn't hesitate to edit below as
13273 @c needed. However if the change you want to make to this documentation
13274 @c can be done in an automated way, it's probably easier to change
13275 @c (generate-documentation) than to make it below and have to deal with
13276 @c the churn as Prosody updates.
13278 Available @code{prosody-configuration} fields are:
13280 @deftypevr {@code{prosody-configuration} parameter} package prosody
13281 The Prosody package.
13284 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
13285 Location of the Prosody data storage directory. See
13286 @url{http://prosody.im/doc/configure}.
13287 Defaults to @samp{"/var/lib/prosody"}.
13290 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
13291 Additional plugin directories. They are searched in all the specified
13292 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
13293 Defaults to @samp{()}.
13296 @deftypevr {@code{prosody-configuration} parameter} string-list admins
13297 This is a list of accounts that are admins for the server. Note that you
13298 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
13299 @url{http://prosody.im/doc/creating_accounts}.
13300 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
13301 Defaults to @samp{()}.
13304 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
13305 Enable use of libevent for better performance under high load. See
13306 @url{http://prosody.im/doc/libevent}.
13307 Defaults to @samp{#f}.
13310 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13311 This is the list of modules Prosody will load on startup. It looks for
13312 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13313 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13314 Defaults to @samp{%default-modules-enabled}.
13317 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13318 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13319 should you want to disable them then add them to this list.
13320 Defaults to @samp{()}.
13323 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13324 Path to a text file where the shared groups are defined. If this path is
13325 empty then @samp{mod_groups} does nothing. See
13326 @url{http://prosody.im/doc/modules/mod_groups}.
13327 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13330 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13331 Disable account creation by default, for security. See
13332 @url{http://prosody.im/doc/creating_accounts}.
13333 Defaults to @samp{#f}.
13336 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13337 These are the SSL/TLS-related settings. Most of them are disabled so to
13338 use Prosody's defaults. If you do not completely understand these options, do
13339 not add them to your config, it is easy to lower the security of your server
13340 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13342 Available @code{ssl-configuration} fields are:
13344 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13345 This determines what handshake to use.
13348 @deftypevr {@code{ssl-configuration} parameter} file-name key
13349 Path to your private key file, relative to @code{/etc/prosody}.
13350 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13353 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13354 Path to your certificate file, relative to @code{/etc/prosody}.
13355 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13358 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13359 Path to directory containing root certificates that you wish Prosody to
13360 trust when verifying the certificates of remote servers.
13361 Defaults to @samp{"/etc/ssl/certs"}.
13364 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13365 Path to a file containing root certificates that you wish Prosody to trust.
13366 Similar to @code{capath} but with all certificates concatenated together.
13369 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13370 A list of verification options (these mostly map to OpenSSL's
13371 @code{set_verify()} flags).
13374 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13375 A list of general options relating to SSL/TLS. These map to OpenSSL's
13376 @code{set_options()}. For a full list of options available in LuaSec, see the
13380 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13381 How long a chain of certificate authorities to check when looking for a
13382 trusted root certificate.
13385 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13386 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13387 clients, and in what order.
13390 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13391 A path to a file containing parameters for Diffie-Hellman key exchange. You
13392 can create such a file with:
13393 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13396 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13397 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13398 @samp{"secp384r1"}.
13401 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13402 A list of "extra" verification options.
13405 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13406 Password for encrypted private keys.
13411 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13412 Whether to force all client-to-server connections to be encrypted or not.
13413 See @url{http://prosody.im/doc/modules/mod_tls}.
13414 Defaults to @samp{#f}.
13417 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13418 Whether to force all server-to-server connections to be encrypted or not.
13419 See @url{http://prosody.im/doc/modules/mod_tls}.
13420 Defaults to @samp{#f}.
13423 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13424 Whether to require encryption and certificate authentication. This
13425 provides ideal security, but requires servers you communicate with to support
13426 encryption AND present valid, trusted certificates. See
13427 @url{http://prosody.im/doc/s2s#security}.
13428 Defaults to @samp{#f}.
13431 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13432 Many servers don't support encryption or have invalid or self-signed
13433 certificates. You can list domains here that will not be required to
13434 authenticate using certificates. They will be authenticated using DNS. See
13435 @url{http://prosody.im/doc/s2s#security}.
13436 Defaults to @samp{()}.
13439 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13440 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13441 valid certificates for some domains by specifying a list here. See
13442 @url{http://prosody.im/doc/s2s#security}.
13443 Defaults to @samp{()}.
13446 @deftypevr {@code{prosody-configuration} parameter} string authentication
13447 Select the authentication backend to use. The default provider stores
13448 passwords in plaintext and uses Prosody's configured data storage to store the
13449 authentication data. If you do not trust your server please see
13450 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13451 about using the hashed backend. See also
13452 @url{http://prosody.im/doc/authentication}
13453 Defaults to @samp{"internal_plain"}.
13456 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13457 Set logging options. Advanced logging configuration is not yet supported
13458 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13459 Defaults to @samp{"*syslog"}.
13462 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13463 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13464 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13467 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13468 A host in Prosody is a domain on which user accounts can be created. For
13469 example if you want your users to have addresses like
13470 @samp{"john.smith@@example.com"} then you need to add a host
13471 @samp{"example.com"}. All options in this list will apply only to this host.
13473 Note: the name "virtual" host is used in configuration to avoid confusion with
13474 the actual physical host that Prosody is installed on. A single Prosody
13475 instance can serve many domains, each one defined as a VirtualHost entry in
13476 Prosody's configuration. Conversely a server that hosts a single domain would
13477 have just one VirtualHost entry.
13479 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13481 Available @code{virtualhost-configuration} fields are:
13483 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:
13484 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13485 Domain you wish Prosody to serve.
13490 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13491 Components are extra services on a server which are available to clients,
13492 usually on a subdomain of the main server (such as
13493 @samp{"mycomponent.example.com"}). Example components might be chatroom
13494 servers, user directories, or gateways to other protocols.
13496 Internal components are implemented with Prosody-specific plugins. To add an
13497 internal component, you simply fill the hostname field, and the plugin you wish
13498 to use for the component.
13500 See @url{http://prosody.im/doc/components}.
13501 Defaults to @samp{()}.
13503 Available @code{int-component-configuration} fields are:
13505 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:
13506 @deftypevr {@code{int-component-configuration} parameter} string hostname
13507 Hostname of the component.
13510 @deftypevr {@code{int-component-configuration} parameter} string plugin
13511 Plugin you wish to use for the component.
13514 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13515 Multi-user chat (MUC) is Prosody's module for allowing you to create
13516 hosted chatrooms/conferences for XMPP users.
13518 General information on setting up and using multi-user chatrooms can be found
13519 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13520 which you should read if you are new to XMPP chatrooms.
13522 See also @url{http://prosody.im/doc/modules/mod_muc}.
13524 Available @code{mod-muc-configuration} fields are:
13526 @deftypevr {@code{mod-muc-configuration} parameter} string name
13527 The name to return in service discovery responses.
13528 Defaults to @samp{"Prosody Chatrooms"}.
13531 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13532 If @samp{#t}, this will only allow admins to create new chatrooms.
13533 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13534 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13535 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13536 restricts to service administrators only.
13537 Defaults to @samp{#f}.
13540 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13541 Maximum number of history messages that will be sent to the member that has
13542 just joined the room.
13543 Defaults to @samp{20}.
13550 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13551 External components use XEP-0114, which most standalone components
13552 support. To add an external component, you simply fill the hostname field. See
13553 @url{http://prosody.im/doc/components}.
13554 Defaults to @samp{()}.
13556 Available @code{ext-component-configuration} fields are:
13558 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:
13559 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13560 Password which the component will use to log in.
13563 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13564 Hostname of the component.
13569 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13570 Port(s) Prosody listens on for component connections.
13573 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13574 Interface Prosody listens on for component connections.
13575 Defaults to @samp{"127.0.0.1"}.
13578 It could be that you just want to get a @code{prosody.cfg.lua}
13579 up and running. In that case, you can pass an
13580 @code{opaque-prosody-configuration} record as the value of
13581 @code{prosody-service-type}. As its name indicates, an opaque configuration
13582 does not have easy reflective capabilities.
13583 Available @code{opaque-prosody-configuration} fields are:
13585 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13586 The prosody package.
13589 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13590 The contents of the @code{prosody.cfg.lua} to use.
13593 For example, if your @code{prosody.cfg.lua} is just the empty
13594 string, you could instantiate a prosody service like this:
13597 (service prosody-service-type
13598 (opaque-prosody-configuration
13599 (prosody.cfg.lua "")))
13602 @node Kerberos Services
13603 @subsubsection Kerberos Services
13606 The @code{(gnu services kerberos)} module provides services relating to
13607 the authentication protocol @dfn{Kerberos}.
13609 @subsubheading Krb5 Service
13611 Programs using a Kerberos client library normally
13612 expect a configuration file in @file{/etc/krb5.conf}.
13613 This service generates such a file from a definition provided in the
13614 operating system declaration.
13615 It does not cause any daemon to be started.
13617 No ``keytab'' files are provided by this service---you must explicitly create them.
13618 This service is known to work with the MIT client library, @code{mit-krb5}.
13619 Other implementations have not been tested.
13621 @defvr {Scheme Variable} krb5-service-type
13622 A service type for Kerberos 5 clients.
13626 Here is an example of its use:
13628 (service krb5-service-type
13629 (krb5-configuration
13630 (default-realm "EXAMPLE.COM")
13631 (allow-weak-crypto? #t)
13634 (name "EXAMPLE.COM")
13635 (admin-server "groucho.example.com")
13636 (kdc "karl.example.com"))
13639 (admin-server "kerb-admin.argrx.edu")
13640 (kdc "keys.argrx.edu"))))))
13644 This example provides a Kerberos@tie{}5 client configuration which:
13646 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13647 of which have distinct administration servers and key distribution centers;
13648 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13649 specified by clients;
13650 @item Accepts services which only support encryption types known to be weak.
13653 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13654 Only the most commonly used ones are described here.
13655 For a full list, and more detailed explanation of each, see the MIT
13656 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13660 @deftp {Data Type} krb5-realm
13661 @cindex realm, kerberos
13664 This field is a string identifying the name of the realm.
13665 A common convention is to use the fully qualified DNS name of your organization,
13666 converted to upper case.
13668 @item @code{admin-server}
13669 This field is a string identifying the host where the administration server is
13673 This field is a string identifying the key distribution center
13678 @deftp {Data Type} krb5-configuration
13681 @item @code{allow-weak-crypto?} (default: @code{#f})
13682 If this flag is @code{#t} then services which only offer encryption algorithms
13683 known to be weak will be accepted.
13685 @item @code{default-realm} (default: @code{#f})
13686 This field should be a string identifying the default Kerberos
13687 realm for the client.
13688 You should set this field to the name of your Kerberos realm.
13689 If this value is @code{#f}
13690 then a realm must be specified with every Kerberos principal when invoking programs
13691 such as @command{kinit}.
13693 @item @code{realms}
13694 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13696 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13702 @subsubheading PAM krb5 Service
13705 The @code{pam-krb5} service allows for login authentication and password
13706 management via Kerberos.
13707 You will need this service if you want PAM enabled applications to authenticate
13708 users using Kerberos.
13710 @defvr {Scheme Variable} pam-krb5-service-type
13711 A service type for the Kerberos 5 PAM module.
13714 @deftp {Data Type} pam-krb5-configuration
13715 Data type representing the configuration of the Kerberos 5 PAM module
13716 This type has the following parameters:
13718 @item @code{pam-krb5} (default: @code{pam-krb5})
13719 The pam-krb5 package to use.
13721 @item @code{minimum-uid} (default: @code{1000})
13722 The smallest user ID for which Kerberos authentications should be attempted.
13723 Local accounts with lower values will silently fail to authenticate.
13729 @subsubsection Web Services
13734 The @code{(gnu services web)} module provides the following service:
13736 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13737 [#:log-directory ``/var/log/nginx''] @
13738 [#:run-directory ``/var/run/nginx''] @
13739 [#:server-list '()] @
13740 [#:upstream-list '()] @
13741 [#:config-file @code{#f}]
13743 Return a service that runs @var{nginx}, the nginx web server.
13745 The nginx daemon loads its runtime configuration from @var{config-file}.
13746 Log files are written to @var{log-directory} and temporary runtime data
13747 files are written to @var{run-directory}. For proper operation, these
13748 arguments should match what is in @var{config-file} to ensure that the
13749 directories are created when the service is activated.
13751 As an alternative to using a @var{config-file}, @var{server-list} can be
13752 used to specify the list of @dfn{server blocks} required on the host and
13753 @var{upstream-list} can be used to specify a list of @dfn{upstream
13754 blocks} to configure. For this to work, use the default value for
13757 At startup, @command{nginx} has not yet read its configuration file, so it
13758 uses a default file to log error messages. If it fails to load its
13759 configuration file, that is where error messages are logged. After the
13760 configuration file is loaded, the default error log file changes as per
13761 configuration. In our case, startup error messages can be found in
13762 @file{/var/run/nginx/logs/error.log}, and after configuration in
13763 @file{/var/log/nginx/error.log}. The second location can be changed with the
13764 @var{log-directory} configuration option.
13768 @deffn {Scheme Variable} nginx-service-type
13769 This is type for the nginx web server.
13771 This service can be extended to add server blocks in addition to the
13772 default one, as in this example:
13775 (simple-service 'my-extra-server nginx-service-type
13776 (list (nginx-server-configuration
13778 (root "/srv/http/extra-website"))))
13782 @deftp {Data Type} nginx-server-configuration
13783 Data type representing the configuration of an nginx server block.
13784 This type has the following parameters:
13787 @item @code{http-port} (default: @code{80})
13788 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13789 nginx should not listen for HTTP (non secure) connection for this
13790 @dfn{server block}.
13792 @item @code{https-port} (default: @code{443})
13793 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13794 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13796 Note that nginx can listen for HTTP and HTTPS connections in the same
13797 @dfn{server block}.
13799 @item @code{server-name} (default: @code{(list 'default)})
13800 A list of server names this server represents. @code{'default} represents the
13801 default server for connections matching no other server.
13803 @item @code{root} (default: @code{"/srv/http"})
13804 Root of the website nginx will serve.
13806 @item @code{locations} (default: @code{'()})
13807 A list of @dfn{nginx-location-configuration} or
13808 @dfn{nginx-named-location-configuration} records to use within this
13811 @item @code{index} (default: @code{(list "index.html")})
13812 Index files to look for when clients ask for a directory. If it cannot be found,
13813 Nginx will send the list of files in the directory.
13815 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13816 Where to find the certificate for secure connections. Set it to @code{#f} if
13817 you don't have a certificate or you don't want to use HTTPS.
13819 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13820 Where to find the private key for secure connections. Set it to @code{#f} if
13821 you don't have a key or you don't want to use HTTPS.
13823 @item @code{server-tokens?} (default: @code{#f})
13824 Whether the server should add its configuration to response.
13829 @deftp {Data Type} nginx-upstream-configuration
13830 Data type representing the configuration of an nginx @code{upstream}
13831 block. This type has the following parameters:
13835 Name for this group of servers.
13837 @item @code{servers}
13838 Specify the addresses of the servers in the group. The address can be
13839 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13840 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13841 prefix @samp{unix:}. For addresses using an IP address or domain name,
13842 the default port is 80, and a different port can be specified
13848 @deftp {Data Type} nginx-location-configuration
13849 Data type representing the configuration of an nginx @code{location}
13850 block. This type has the following parameters:
13854 URI which this location block matches.
13856 @anchor{nginx-location-configuration body}
13858 Body of the location block, specified as a string. This can contain many
13859 configuration directives. For example, to pass requests to a upstream
13860 server group defined using an @code{nginx-upstream-configuration} block,
13861 the following directive would be specified in the body @samp{proxy_pass
13862 http://upstream-name;}.
13867 @deftp {Data Type} nginx-named-location-configuration
13868 Data type representing the configuration of an nginx named location
13869 block. Named location blocks are used for request redirection, and not
13870 used for regular request processing. This type has the following
13875 Name to identify this location block.
13878 @xref{nginx-location-configuration body}, as the body for named location
13879 blocks can be used in a similar way to the
13880 @code{nginx-location-configuration body}. One restriction is that the
13881 body of a named location block cannot contain location blocks.
13888 @subsubsection DNS Services
13889 @cindex DNS (domain name system)
13890 @cindex domain name system (DNS)
13892 The @code{(gnu services dns)} module provides services related to the
13893 @dfn{domain name system} (DNS). It provides a server service for hosting
13894 an @emph{authoritative} DNS server for multiple zones, slave or master.
13895 This service uses @uref{https://www.knot-dns.cz/, Knot DNS}.
13897 An example configuration of an authoritative server for two zones, one master
13901 (define-zone-entries example.org.zone
13902 ;; Name TTL Class Type Data
13903 ("@@" "" "IN" "A" "127.0.0.1")
13904 ("@@" "" "IN" "NS" "ns")
13905 ("ns" "" "IN" "A" "127.0.0.1"))
13907 (define master-zone
13908 (knot-zone-configuration
13909 (domain "example.org")
13911 (origin "example.org")
13912 (entries example.org.zone)))))
13915 (knot-zone-configuration
13916 (domain "plop.org")
13917 (dnssec-policy "default")
13918 (master (list "plop-master"))))
13920 (define plop-master
13921 (knot-remote-configuration
13923 (address (list "208.76.58.171"))))
13927 (services (cons* (service knot-service-type
13928 (knot-confifguration
13929 (remotes (list plop-master))
13930 (zones (list master-zone slave-zone))))
13935 @deffn {Scheme Variable} knot-service-type
13936 This is the type for the Knot DNS server.
13938 Knot DNS is an authoritative DNS server, meaning that it can serve multiple
13939 zones, that is to say domain names you would buy from a registrar. This server
13940 is not a resolver, meaning that it can only resolve names for which it is
13941 authoritative. This server can be configured to serve zones as a master server
13942 or a slave server as a per-zone basis. Slave zones will get their data from
13943 masters, and will serve it as an authoritative server. From the point of view
13944 of a resolver, there is no difference between master and slave.
13946 The following data types are used to configure the Knot DNS server:
13949 @deftp {Data Type} knot-key-configuration
13950 Data type representing a key.
13951 This type has the following parameters:
13954 @item @code{id} (default: @code{""})
13955 An identifier for other configuration fields to refer to this key. IDs must
13956 be unique and must not be empty.
13958 @item @code{algorithm} (default: @code{#f})
13959 The algorithm to use. Choose between @code{#f}, @code{'hmac-md5},
13960 @code{'hmac-sha1}, @code{'hmac-sha224}, @code{'hmac-sha256}, @code{'hmac-sha384}
13961 and @code{'hmac-sha512}.
13963 @item @code{secret} (default: @code{""})
13964 The secret key itself.
13969 @deftp {Data Type} knot-acl-configuration
13970 Data type representing an Access Control List (ACL) configuration.
13971 This type has the following parameters:
13974 @item @code{id} (default: @code{""})
13975 An identifier for ether configuration fields to refer to this key. IDs must be
13976 unique and must not be empty.
13978 @item @code{address} (default: @code{'()})
13979 An ordered list of IP addresses, network subnets, or network ranges represented
13980 with strings. The query must match one of them. Empty value means that
13981 address match is not required.
13983 @item @code{key} (default: @code{'()})
13984 An ordered list of references to keys represented with strings. The string
13985 must match a key ID defined in a @code{knot-key-configuration}. No key means
13986 that a key is not require to match that ACL.
13988 @item @code{action} (default: @code{'()})
13989 An ordered list of actions that are permitted or forbidden by this ACL. Possible
13990 values are lists of zero or more elements from @code{'transfer}, @code{'notify}
13991 and @code{'update}.
13993 @item @code{deny?} (default: @code{#f})
13994 When true, the ACL defines restrictions. Listed actions are forbidden. When
13995 false, listed actions are allowed.
14000 @deftp {Data Type} zone-entry
14001 Data type represnting a record entry in a zone file.
14002 This type has the following parameters:
14005 @item @code{name} (default: @code{"@@"})
14006 The name of the record. @code{"@@"} refers to the origin of the zone. Names
14007 are relative to the origin of the zone. For example, in the @code{example.org}
14008 zone, @code{"ns.example.org"} actually refers to @code{ns.example.org.example.org}.
14009 Names ending with a dot are absolute, which means that @code{"ns.example.org."}
14010 refers to @code{ns.example.org}.
14012 @item @code{ttl} (default: @code{""})
14013 The Time-To-Live (TTL) of this record. If not set, the default TTL is used.
14015 @item @code{class} (default: @code{"IN"})
14016 The class of the record. Knot currently supports only @code{"IN"} and
14017 partially @code{"CH"}.
14019 @item @code{type} (default: @code{"A"})
14020 The type of the record. Common types include A (IPv4 address), AAAA (IPv6
14021 address), NS (Name Server) and MX (Mail eXchange). Many other types are
14024 @item @code{data} (default: @code{""})
14025 The data contained in the record. For instance an IP address associated with
14026 an A record, or a domain name associated with an NS record. Remember that
14027 domain names are relative to the origin unless they end with a dot.
14032 @deftp {Data Type} zone-file
14033 Data type representing the content of a zone file.
14034 This type has the following parameters:
14037 @item @code{entries} (default: @code{'()})
14038 The list of entries. The SOA record is taken care of, so you don't need to
14039 put it in the list of entries. This list should probably contain an entry
14040 for your primary authoritative DNS server. Other than using a list of entries
14041 directly, you can use @code{define-zone-entries} to define a object containing
14042 the list of entries more easily, that you can later pass to the @code{entries}
14043 field of the @code{zone-file}.
14045 @item @code{origin} (default: @code{""})
14046 The name of your zone. This parameter cannot be empty.
14048 @item @code{ns} (default: @code{"ns"})
14049 The domain of your primary authoritative DNS server. The name is relative to
14050 the origin, unless it ends with a dot. It is mandatory that this primary
14051 DNS server corresponds to an NS record in the zone and that it is associated
14052 to an IP address in the list of entries.
14054 @item @code{mail} (default: @code{"hostmaster"})
14055 An email address people can contact you at, as the owner of the zone. This
14056 is translated as @code{<mail>@@<origin>}.
14058 @item @code{serial} (default: @code{1})
14059 The serial number of the zone. As this is used to keep track of changes by
14060 both slaves and resolvers, it is mandatory that it @emph{never} decreases.
14061 Always increment it when you make a change in your zone.
14063 @item @code{refresh} (default: @code{(* 2 24 3600)})
14064 The frequency at which slaves will do a zone transfer. This value is a number
14065 of seconds. It can be computed by multiplications or with
14066 @code{(string->duration)}.
14068 @item @code{retry} (default: @code{(* 15 60)})
14069 The period after which a slave will retry to contact its master when it fails
14070 to do so a first time.
14072 @item @code{expiry} (default: @code{(* 14 24 3600)})
14073 Default TTL of records. Existing records are considered correct for at most
14074 this amount of time. After this period, resolvers will invalidate their cache
14075 and check again that it still exists.
14077 @item @code{nx} (default: @code{3600})
14078 Default TTL of inexistant records. This delay is usually short because you want
14079 your new domains to reach everyone quickly.
14084 @deftp {Data Type} knot-remote-configuration
14085 Data type representing a remote configuration.
14086 This type has the following parameters:
14089 @item @code{id} (default: @code{""})
14090 An identifier for other configuration fields to refer to this remote. IDs must
14091 be unique and must not be empty.
14093 @item @code{address} (default: @code{'()})
14094 An ordered list of destination IP addresses. Addresses are tried in sequence.
14095 An optional port can be given with the @@ separator. For instance:
14096 @code{(list "1.2.3.4" "2.3.4.5@@53")}. Default port is 53.
14098 @item @code{via} (default: @code{'()})
14099 An ordered list of source IP addresses. An empty list will have Knot choose
14100 an appropriate source IP. An optional port can be given with the @@ separator.
14101 The default is to choose at random.
14103 @item @code{key} (default: @code{#f})
14104 A reference to a key, that is a string containing the identifier of a key
14105 defined in a @code{knot-key-configuration} field.
14110 @deftp {Data Type} knot-keystore-configuration
14111 Data type representing a keystore to hold dnssec keys.
14112 This type has the following parameters:
14115 @item @code{id} (default: @code{""})
14116 The id of the keystore. It must not be empty.
14118 @item @code{backend} (default: @code{'pem})
14119 The backend to store the keys in. Can be @code{'pem} or @code{'pkcs11}.
14121 @item @code{config} (default: @code{"/var/lib/knot/keys/keys"})
14122 The configuration string of the backend. An example for the PKCS#11 is:
14123 @code{"pkcs11:token=knot;pin-value=1234 /gnu/store/.../lib/pkcs11/libsofthsm2.so"}.
14124 For the pem backend, the string reprensents a path in the filesystem.
14129 @deftp {Data Type} knot-policy-configuration
14130 Data type representing a dnssec policy. Knot DNS is able to automatically
14131 sign your zones. It can either generate and manage your keys automatically or
14132 use keys that you generate.
14134 Dnssec is usually implemented using two keys: a Key Signing Key (KSK) that is
14135 used to sign the second, and a Zone Signing Key (ZSK) that is used to sign the
14136 zone. In order to be trusted, the KSK needs to be present in the parent zone
14137 (usually a top-level domain). If your registrar supports dnssec, you will
14138 have to send them your KSK's hash so they can add a DS record in their zone.
14139 This is not automated and need to be done each time you change your KSK.
14141 The policy also defines the lifetime of keys. Usually, ZSK can be changed
14142 easily and use weaker cryptographic functions (they use lower parameters) in
14143 order to sign records quickly, so they are changed often. The KSK however
14144 requires manual interaction with the registrar, so they are changed less often
14145 and use stronger parameters because they sign only one record.
14147 This type has the following parameters:
14150 @item @code{id} (default: @code{""})
14151 The id of the policy. It must not be empty.
14153 @item @code{keystore} (default: @code{"default"})
14154 A reference to a keystore, that is a string containing the identifier of a
14155 keystore defined in a @code{knot-keystore-configuration} field. The
14156 @code{"default"} identifier means the default keystore (a kasp database that
14157 was setup by this service).
14159 @item @code{manual?} (default: @code{#f})
14160 Whether the key management is manual or automatic.
14162 @item @code{single-type-signing?} (default: @code{#f})
14163 When @code{#t}, use the Single-Type Signing Scheme.
14165 @item @code{algorithm} (default: @code{"ecdsap256sha256"})
14166 An algorithm of signing keys and issued signatures.
14168 @item @code{ksk-size} (default: @code{256})
14169 The length of the KSK. Note that this value is correct for the default
14170 algorithm, but would be unsecure for other algorithms.
14172 @item @code{zsk-size} (default: @code{256})
14173 The length of the ZSK. Note that this value is correct for the default
14174 algorithm, but would be unsecure for other algorithms.
14176 @item @code{dnskey-ttl} (default: @code{'default})
14177 The TTL value for DNSKEY records added into zone apex. The special
14178 @code{'default} value means same as the zone SOA TTL.
14180 @item @code{zsk-lifetime} (default: @code{(* 30 24 3600)})
14181 The period between ZSK publication and the next rollover initiation.
14183 @item @code{propagation-delay} (default: @code{(* 24 3600)})
14184 An extra delay added for each key rollover step. This value should be high
14185 enough to cover propagation of data from the master server to all slaves.
14187 @item @code{rrsig-lifetime} (default: @code{(* 14 24 3600)})
14188 A validity period of newly issued signatures.
14190 @item @code{rrsig-refresh} (default: @code{(* 7 24 3600)})
14191 A period how long before a signature expiration the signature will be refreshed.
14193 @item @code{nsec3?} (default: @code{#f})
14194 When @code{#t}, NSEC3 will be used instead of NSEC.
14196 @item @code{nsec3-iterations} (default: @code{5})
14197 The number of additional times the hashing is performed.
14199 @item @code{nsec3-salt-length} (default: @code{8})
14200 The length of a salt field in octets, which is appended to the original owner
14201 name before hashing.
14203 @item @code{nsec3-salt-lifetime} (default: @code{(* 30 24 3600)})
14204 The validity period of newly issued salt field.
14209 @deftp {Data Type} knot-zone-configuration
14210 Data type representing a zone served by Knot.
14211 This type has the following parameters:
14214 @item @code{domain} (default: @code{""})
14215 The domain served by this configuration. It must not be empty.
14217 @item @code{file} (default: @code{""})
14218 The file where this zone is saved. This parameter is ignored by master zones.
14219 Empty means default location that depends on the domain name.
14221 @item @code{zone} (default: @code{(zone-file)})
14222 The content of the zone file. This parameter is ignored by slave zones. It
14223 must contain a zone-file record.
14225 @item @code{master} (default: @code{'()})
14226 A list of master remotes. When empty, this zone is a master. When set, this
14227 zone is a slave. This is a list of remotes identifiers.
14229 @item @code{ddns-master} (default: @code{#f})
14230 The main master. When empty, it defaults to the first master in the list of
14233 @item @code{notify} (default: @code{'()})
14234 A list of slave remote identifiers.
14236 @item @code{acl} (default: @code{'()})
14237 A list of acl identifiers.
14239 @item @code{semantic-checks?} (default: @code{#f})
14240 When set, this adds more semantic checks to the zone.
14242 @item @code{disable-any?} (default: @code{#f})
14243 When set, this forbids queries of the ANY type.
14245 @item @code{zonefile-sync} (default: @code{0})
14246 The delay between a modification in memory and on disk. 0 means immediate
14249 @item @code{serial-policy} (default: @code{'increment})
14250 A policy between @code{'increment} and @code{'unixtime}.
14255 @deftp {Data Type} knot-configuration
14256 Data type representing the Knot configuration.
14257 This type has the following parameters:
14260 @item @code{knot} (default: @code{knot})
14263 @item @code{run-directory} (default: @code{"/var/run/knot"})
14264 The run directory. This directory will be used for pid file and sockets.
14266 @item @code{listen-v4} (default: @code{"0.0.0.0"})
14267 An ip address on which to listen.
14269 @item @code{listen-v6} (default: @code{"::"})
14270 An ip address on which to listen.
14272 @item @code{listen-port} (default: @code{53})
14273 A port on which to listen.
14275 @item @code{keys} (default: @code{'()})
14276 The list of knot-key-configuration used by this configuration.
14278 @item @code{acls} (default: @code{'()})
14279 The list of knot-acl-configuration used by this configuration.
14281 @item @code{remotes} (default: @code{'()})
14282 The list of knot-remote-configuration used by this configuration.
14284 @item @code{zones} (default: @code{'()})
14285 The list of knot-zone-configuration used by this configuration.
14291 @subsubsection VPN Services
14292 @cindex VPN (virtual private network)
14293 @cindex virtual private network (VPN)
14295 The @code{(gnu services vpn)} module provides services related to
14296 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
14297 your machine to connect to a VPN, and a @emph{servire} service for your machine
14298 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
14300 @deffn {Scheme Procedure} openvpn-client-service @
14301 [#:config (openvpn-client-configuration)]
14303 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
14306 @deffn {Scheme Procedure} openvpn-server-service @
14307 [#:config (openvpn-server-configuration)]
14309 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
14311 Both can be run simultaneously.
14314 @c %automatically generated documentation
14316 Available @code{openvpn-client-configuration} fields are:
14318 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
14319 The OpenVPN package.
14323 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
14324 The OpenVPN pid file.
14326 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14330 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
14331 The protocol (UDP or TCP) used to open a channel between clients and
14334 Defaults to @samp{udp}.
14338 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
14339 The device type used to represent the VPN connection.
14341 Defaults to @samp{tun}.
14345 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
14346 The certificate authority to check connections against.
14348 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14352 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
14353 The certificate of the machine the daemon is running on. It should be
14354 signed by the authority given in @code{ca}.
14356 Defaults to @samp{"/etc/openvpn/client.crt"}.
14360 @deftypevr {@code{openvpn-client-configuration} parameter} string key
14361 The key of the machine the daemon is running on. It must be the key whose
14362 certificate is @code{cert}.
14364 Defaults to @samp{"/etc/openvpn/client.key"}.
14368 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
14369 Whether to use the lzo compression algorithm.
14371 Defaults to @samp{#t}.
14375 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
14376 Don't re-read key files across SIGUSR1 or --ping-restart.
14378 Defaults to @samp{#t}.
14382 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
14383 Don't close and reopen TUN/TAP device or run up/down scripts across
14384 SIGUSR1 or --ping-restart restarts.
14386 Defaults to @samp{#t}.
14390 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
14393 Defaults to @samp{3}.
14397 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
14398 Add an additional layer of HMAC authentication on top of the TLS control
14399 channel to protect against DoS attacks.
14401 Defaults to @samp{#f}.
14405 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
14406 Whether to check the server certificate has server usage extension.
14408 Defaults to @samp{#t}.
14412 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
14413 Bind to a specific local port number.
14415 Defaults to @samp{#f}.
14419 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
14420 Retry resolving server address.
14422 Defaults to @samp{#t}.
14426 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
14427 A list of remote servers to connect to.
14429 Defaults to @samp{()}.
14431 Available @code{openvpn-remote-configuration} fields are:
14433 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
14436 Defaults to @samp{"my-server"}.
14440 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
14441 Port number the server listens to.
14443 Defaults to @samp{1194}.
14448 @c %end of automatic openvpn-client documentation
14450 @c %automatically generated documentation
14452 Available @code{openvpn-server-configuration} fields are:
14454 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
14455 The OpenVPN package.
14459 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
14460 The OpenVPN pid file.
14462 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
14466 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
14467 The protocol (UDP or TCP) used to open a channel between clients and
14470 Defaults to @samp{udp}.
14474 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
14475 The device type used to represent the VPN connection.
14477 Defaults to @samp{tun}.
14481 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
14482 The certificate authority to check connections against.
14484 Defaults to @samp{"/etc/openvpn/ca.crt"}.
14488 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
14489 The certificate of the machine the daemon is running on. It should be
14490 signed by the authority given in @code{ca}.
14492 Defaults to @samp{"/etc/openvpn/client.crt"}.
14496 @deftypevr {@code{openvpn-server-configuration} parameter} string key
14497 The key of the machine the daemon is running on. It must be the key whose
14498 certificate is @code{cert}.
14500 Defaults to @samp{"/etc/openvpn/client.key"}.
14504 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
14505 Whether to use the lzo compression algorithm.
14507 Defaults to @samp{#t}.
14511 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
14512 Don't re-read key files across SIGUSR1 or --ping-restart.
14514 Defaults to @samp{#t}.
14518 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
14519 Don't close and reopen TUN/TAP device or run up/down scripts across
14520 SIGUSR1 or --ping-restart restarts.
14522 Defaults to @samp{#t}.
14526 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
14529 Defaults to @samp{3}.
14533 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
14534 Add an additional layer of HMAC authentication on top of the TLS control
14535 channel to protect against DoS attacks.
14537 Defaults to @samp{#f}.
14541 @deftypevr {@code{openvpn-server-configuration} parameter} number port
14542 Specifies the port number on which the server listens.
14544 Defaults to @samp{1194}.
14548 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
14549 An ip and mask specifying the subnet inside the virtual network.
14551 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
14555 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
14556 A CIDR notation specifying the IPv6 subnet inside the virtual network.
14558 Defaults to @samp{#f}.
14562 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
14563 The Diffie-Hellman parameters file.
14565 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
14569 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
14570 The file that records client IPs.
14572 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
14576 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
14577 When true, the server will act as a gateway for its clients.
14579 Defaults to @samp{#f}.
14583 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
14584 When true, clients are allowed to talk to each other inside the VPN.
14586 Defaults to @samp{#f}.
14590 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
14591 Causes ping-like messages to be sent back and forth over the link so
14592 that each side knows when the other side has gone down. @code{keepalive}
14593 requires a pair. The first element is the period of the ping sending,
14594 and the second element is the timeout before considering the other side
14599 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
14600 The maximum number of clients.
14602 Defaults to @samp{100}.
14606 @deftypevr {@code{openvpn-server-configuration} parameter} string status
14607 The status file. This file shows a small report on current connection.
14608 It is truncated and rewritten every minute.
14610 Defaults to @samp{"/var/run/openvpn/status"}.
14614 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
14615 The list of configuration for some clients.
14617 Defaults to @samp{()}.
14619 Available @code{openvpn-ccd-configuration} fields are:
14621 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
14624 Defaults to @samp{"client"}.
14628 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
14631 Defaults to @samp{#f}.
14635 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
14638 Defaults to @samp{#f}.
14645 @c %end of automatic openvpn-server documentation
14648 @node Network File System
14649 @subsubsection Network File System
14652 The @code{(gnu services nfs)} module provides the following services,
14653 which are most commonly used in relation to mounting or exporting
14654 directory trees as @dfn{network file systems} (NFS).
14656 @subsubheading RPC Bind Service
14659 The RPC Bind service provides a facility to map program numbers into
14660 universal addresses.
14661 Many NFS related services use this facility. Hence it is automatically
14662 started when a dependent service starts.
14664 @defvr {Scheme Variable} rpcbind-service-type
14665 A service type for the RPC portmapper daemon.
14669 @deftp {Data Type} rpcbind-configuration
14670 Data type representing the configuration of the RPC Bind Service.
14671 This type has the following parameters:
14673 @item @code{rpcbind} (default: @code{rpcbind})
14674 The rpcbind package to use.
14676 @item @code{warm-start?} (default: @code{#t})
14677 If this parameter is @code{#t}, then the daemon will read a
14678 state file on startup thus reloading state information saved by a previous
14684 @subsubheading Pipefs Pseudo File System
14688 The pipefs file system is used to transfer NFS related data
14689 between the kernel and user space programs.
14691 @defvr {Scheme Variable} pipefs-service-type
14692 A service type for the pipefs pseudo file system.
14695 @deftp {Data Type} pipefs-configuration
14696 Data type representing the configuration of the pipefs pseudo file system service.
14697 This type has the following parameters:
14699 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14700 The directory to which the file system is to be attached.
14705 @subsubheading GSS Daemon Service
14708 @cindex global security system
14710 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14712 Before exchanging RPC requests an RPC client must establish a security
14713 context. Typically this is done using the Kerberos command @command{kinit}
14714 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14716 @defvr {Scheme Variable} gss-service-type
14717 A service type for the Global Security System (GSS) daemon.
14720 @deftp {Data Type} gss-configuration
14721 Data type representing the configuration of the GSS daemon service.
14722 This type has the following parameters:
14724 @item @code{nfs-utils} (default: @code{nfs-utils})
14725 The package in which the @command{rpc.gssd} command is to be found.
14727 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14728 The directory where the pipefs file system is mounted.
14734 @subsubheading IDMAP Daemon Service
14736 @cindex name mapper
14738 The idmap daemon service provides mapping between user IDs and user names.
14739 Typically it is required in order to access file systems mounted via NFSv4.
14741 @defvr {Scheme Variable} idmap-service-type
14742 A service type for the Identity Mapper (IDMAP) daemon.
14745 @deftp {Data Type} idmap-configuration
14746 Data type representing the configuration of the IDMAP daemon service.
14747 This type has the following parameters:
14749 @item @code{nfs-utils} (default: @code{nfs-utils})
14750 The package in which the @command{rpc.idmapd} command is to be found.
14752 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14753 The directory where the pipefs file system is mounted.
14755 @item @code{domain} (default: @code{#f})
14756 The local NFSv4 domain name.
14757 This must be a string or @code{#f}.
14758 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14763 @node Continuous Integration
14764 @subsubsection Continuous Integration
14766 @cindex continuous integration
14767 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14768 integration tool for Guix. It can be used both for development and for
14769 providing substitutes to others (@pxref{Substitutes}).
14771 The @code{(gnu services cuirass)} module provides the following service.
14773 @defvr {Scheme Procedure} cuirass-service-type
14774 The type of the Cuirass service. Its value must be a
14775 @code{cuirass-configuration} object, as described below.
14778 To add build jobs, you have to set the @code{specifications} field of
14779 the configuration. Here is an example of a service defining a build job
14780 based on a specification that can be found in Cuirass source tree. This
14781 service polls the Guix repository and builds a subset of the Guix
14782 packages, as prescribed in the @file{gnu-system.scm} example spec:
14785 (let ((spec #~((#:name . "guix")
14786 (#:url . "git://git.savannah.gnu.org/guix.git")
14787 (#:load-path . ".")
14789 ;; Here we must provide an absolute file name.
14790 ;; We take jobs from one of the examples provided
14792 (#:file . #$(file-append
14794 "/tests/gnu-system.scm"))
14796 (#:proc . hydra-jobs)
14797 (#:arguments (subset . "hello"))
14798 (#:branch . "master"))))
14799 (service cuirass-service-type
14800 (cuirass-configuration
14801 (specifications #~(list #$spec)))))
14804 While information related to build jobs is located directly in the
14805 specifications, global settings for the @command{cuirass} process are
14806 accessible in other @code{cuirass-configuration} fields.
14808 @deftp {Data Type} cuirass-configuration
14809 Data type representing the configuration of Cuirass.
14812 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14813 Location of the log file.
14815 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14816 Location of the repository cache.
14818 @item @code{user} (default: @code{"cuirass"})
14819 Owner of the @code{cuirass} process.
14821 @item @code{group} (default: @code{"cuirass"})
14822 Owner's group of the @code{cuirass} process.
14824 @item @code{interval} (default: @code{60})
14825 Number of seconds between the poll of the repositories followed by the
14828 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14829 Location of sqlite database which contains the build results and previously
14830 added specifications.
14832 @item @code{port} (default: @code{8080})
14833 Port number used by the HTTP server.
14835 @item @code{specifications} (default: @code{#~'()})
14836 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14837 where a specification is an association list
14838 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14839 keys are keywords (@code{#:keyword-example}) as shown in the example
14842 @item @code{use-substitutes?} (default: @code{#f})
14843 This allows using substitutes to avoid building every dependencies of a job
14846 @item @code{one-shot?} (default: @code{#f})
14847 Only evaluate specifications and build derivations once.
14849 @item @code{fallback?} (default: @code{#f})
14850 When substituting a pre-built binary fails, fall back to building
14853 @item @code{load-path} (default: @code{'()})
14854 This allows users to define their own packages and make them visible to
14855 cuirass as in @command{guix build} command.
14857 @item @code{cuirass} (default: @code{cuirass})
14858 The Cuirass package to use.
14862 @node Power management Services
14863 @subsubsection Power management Services
14865 @cindex power management with TLP
14866 The @code{(gnu services pm)} module provides a Guix service definition
14867 for the Linux power management tool TLP.
14869 TLP enables various powersaving modes in userspace and kernel.
14870 Contrary to @code{upower-service}, it is not a passive,
14871 monitoring tool, as it will apply custom settings each time a new power
14872 source is detected. More information can be found at
14873 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14875 @deffn {Scheme Variable} tlp-service-type
14876 The service type for the TLP tool. Its value should be a valid
14877 TLP configuration (see below). To use the default settings, simply
14880 (service tlp-service-type)
14884 By default TLP does not need much configuration but most TLP parameters
14885 can be tweaked using @code{tlp-configuration}.
14887 Each parameter definition is preceded by its type; for example,
14888 @samp{boolean foo} indicates that the @code{foo} parameter
14889 should be specified as a boolean. Types starting with
14890 @code{maybe-} denote parameters that won't show up in TLP config file
14891 when their value is @code{'disabled}.
14893 @c The following documentation was initially generated by
14894 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14895 @c documentation is better, so we shouldn't hesitate to edit below as
14896 @c needed. However if the change you want to make to this documentation
14897 @c can be done in an automated way, it's probably easier to change
14898 @c (generate-documentation) than to make it below and have to deal with
14899 @c the churn as TLP updates.
14901 Available @code{tlp-configuration} fields are:
14903 @deftypevr {@code{tlp-configuration} parameter} package tlp
14908 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14909 Set to true if you wish to enable TLP.
14911 Defaults to @samp{#t}.
14915 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14916 Default mode when no power supply can be detected. Alternatives are AC
14919 Defaults to @samp{"AC"}.
14923 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14924 Number of seconds Linux kernel has to wait after the disk goes idle,
14925 before syncing on AC.
14927 Defaults to @samp{0}.
14931 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14932 Same as @code{disk-idle-ac} but on BAT mode.
14934 Defaults to @samp{2}.
14938 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14939 Dirty pages flushing periodicity, expressed in seconds.
14941 Defaults to @samp{15}.
14945 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14946 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14948 Defaults to @samp{60}.
14952 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14953 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14954 alternatives are powersave and performance. With acpi-cpufreq driver,
14955 alternatives are ondemand, powersave, performance and conservative.
14957 Defaults to @samp{disabled}.
14961 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14962 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14964 Defaults to @samp{disabled}.
14968 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14969 Set the min available frequency for the scaling governor on AC.
14971 Defaults to @samp{disabled}.
14975 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14976 Set the max available frequency for the scaling governor on AC.
14978 Defaults to @samp{disabled}.
14982 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14983 Set the min available frequency for the scaling governor on BAT.
14985 Defaults to @samp{disabled}.
14989 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14990 Set the max available frequency for the scaling governor on BAT.
14992 Defaults to @samp{disabled}.
14996 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14997 Limit the min P-state to control the power dissipation of the CPU, in AC
14998 mode. Values are stated as a percentage of the available performance.
15000 Defaults to @samp{disabled}.
15004 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
15005 Limit the max P-state to control the power dissipation of the CPU, in AC
15006 mode. Values are stated as a percentage of the available performance.
15008 Defaults to @samp{disabled}.
15012 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
15013 Same as @code{cpu-min-perf-on-ac} on BAT mode.
15015 Defaults to @samp{disabled}.
15019 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
15020 Same as @code{cpu-max-perf-on-ac} on BAT mode.
15022 Defaults to @samp{disabled}.
15026 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
15027 Enable CPU turbo boost feature on AC mode.
15029 Defaults to @samp{disabled}.
15033 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
15034 Same as @code{cpu-boost-on-ac?} on BAT mode.
15036 Defaults to @samp{disabled}.
15040 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
15041 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
15042 used under light load conditions.
15044 Defaults to @samp{#f}.
15048 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
15049 Same as @code{sched-powersave-on-ac?} but on BAT mode.
15051 Defaults to @samp{#t}.
15055 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
15056 Enable Linux kernel NMI watchdog.
15058 Defaults to @samp{#f}.
15062 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
15063 For Linux kernels with PHC patch applied, change CPU voltages. An
15064 example value would be @samp{"F:V F:V F:V F:V"}.
15066 Defaults to @samp{disabled}.
15070 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
15071 Set CPU performance versus energy saving policy on AC. Alternatives are
15072 performance, normal, powersave.
15074 Defaults to @samp{"performance"}.
15078 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
15079 Same as @code{energy-perf-policy-ac} but on BAT mode.
15081 Defaults to @samp{"powersave"}.
15085 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
15090 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
15091 Hard disk advanced power management level.
15095 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
15096 Same as @code{disk-apm-bat} but on BAT mode.
15100 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
15101 Hard disk spin down timeout. One value has to be specified for each
15102 declared hard disk.
15104 Defaults to @samp{disabled}.
15108 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
15109 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
15111 Defaults to @samp{disabled}.
15115 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
15116 Select IO scheduler for disk devices. One value has to be specified for
15117 each declared hard disk. Example alternatives are cfq, deadline and
15120 Defaults to @samp{disabled}.
15124 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
15125 SATA aggressive link power management (ALPM) level. Alternatives are
15126 min_power, medium_power, max_performance.
15128 Defaults to @samp{"max_performance"}.
15132 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
15133 Same as @code{sata-linkpwr-ac} but on BAT mode.
15135 Defaults to @samp{"min_power"}.
15139 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
15140 Exclude specified SATA host devices for link power management.
15142 Defaults to @samp{disabled}.
15146 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
15147 Enable Runtime Power Management for AHCI controller and disks on AC
15150 Defaults to @samp{disabled}.
15154 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
15155 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
15157 Defaults to @samp{disabled}.
15161 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
15162 Seconds of inactivity before disk is suspended.
15164 Defaults to @samp{15}.
15168 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
15169 PCI Express Active State Power Management level. Alternatives are
15170 default, performance, powersave.
15172 Defaults to @samp{"performance"}.
15176 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
15177 Same as @code{pcie-aspm-ac} but on BAT mode.
15179 Defaults to @samp{"powersave"}.
15183 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
15184 Radeon graphics clock speed level. Alternatives are low, mid, high,
15187 Defaults to @samp{"high"}.
15191 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
15192 Same as @code{radeon-power-ac} but on BAT mode.
15194 Defaults to @samp{"low"}.
15198 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
15199 Radeon dynamic power management method (DPM). Alternatives are battery,
15202 Defaults to @samp{"performance"}.
15206 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
15207 Same as @code{radeon-dpm-state-ac} but on BAT mode.
15209 Defaults to @samp{"battery"}.
15213 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
15214 Radeon DPM performance level. Alternatives are auto, low, high.
15216 Defaults to @samp{"auto"}.
15220 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
15221 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
15223 Defaults to @samp{"auto"}.
15227 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
15228 Wifi power saving mode.
15230 Defaults to @samp{#f}.
15234 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
15235 Same as @code{wifi-power-ac?} but on BAT mode.
15237 Defaults to @samp{#t}.
15241 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
15242 Disable wake on LAN.
15244 Defaults to @samp{#t}.
15248 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
15249 Timeout duration in seconds before activating audio power saving on
15250 Intel HDA and AC97 devices. A value of 0 disables power saving.
15252 Defaults to @samp{0}.
15256 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
15257 Same as @code{sound-powersave-ac} but on BAT mode.
15259 Defaults to @samp{1}.
15263 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
15264 Disable controller in powersaving mode on Intel HDA devices.
15266 Defaults to @samp{#t}.
15270 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
15271 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
15272 powered on again by releasing (and reinserting) the eject lever or by
15273 pressing the disc eject button on newer models.
15275 Defaults to @samp{#f}.
15279 @deftypevr {@code{tlp-configuration} parameter} string bay-device
15280 Name of the optical drive device to power off.
15282 Defaults to @samp{"sr0"}.
15286 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
15287 Runtime Power Management for PCI(e) bus devices. Alternatives are on
15290 Defaults to @samp{"on"}.
15294 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
15295 Same as @code{runtime-pm-ac} but on BAT mode.
15297 Defaults to @samp{"auto"}.
15301 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
15302 Runtime Power Management for all PCI(e) bus devices, except blacklisted
15305 Defaults to @samp{#t}.
15309 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
15310 Exclude specified PCI(e) device addresses from Runtime Power Management.
15312 Defaults to @samp{disabled}.
15316 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
15317 Exclude PCI(e) devices assigned to the specified drivers from Runtime
15322 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
15323 Enable USB autosuspend feature.
15325 Defaults to @samp{#t}.
15329 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
15330 Exclude specified devices from USB autosuspend.
15332 Defaults to @samp{disabled}.
15336 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
15337 Exclude WWAN devices from USB autosuspend.
15339 Defaults to @samp{#t}.
15343 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
15344 Include specified devices into USB autosuspend, even if they are already
15345 excluded by the driver or via @code{usb-blacklist-wwan?}.
15347 Defaults to @samp{disabled}.
15351 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
15352 Enable USB autosuspend before shutdown.
15354 Defaults to @samp{disabled}.
15358 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
15359 Restore radio device state (bluetooth, wifi, wwan) from previous
15360 shutdown on system startup.
15362 Defaults to @samp{#f}.
15367 The @code{(gnu services pm)} module provides an interface to
15368 thermald, a CPU frequency scaling service which helps prevent overheating.
15370 @defvr {Scheme Variable} thermald-service-type
15371 This is the service type for
15372 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
15373 Thermal Daemon, which is responsible for controlling the thermal state
15374 of processors and preventing overheating.
15377 @deftp {Data Type} thermald-configuration
15378 Data type representing the configuration of @code{thermald-service-type}.
15381 @item @code{ignore-cpuid-check?} (default: @code{#f})
15382 Ignore cpuid check for supported CPU models.
15384 @item @code{thermald} (default: @var{thermald})
15385 Package object of thermald.
15391 @node Miscellaneous Services
15392 @subsubsection Miscellaneous Services
15395 @subsubheading System Control Service
15397 The @code{(gnu services sysctl)} provides a service to configure kernel
15398 parameters at boot.
15400 @defvr {Scheme Variable} sysctl-service-type
15401 The service type for @command{sysctl}, which modifies kernel parameters
15402 under @file{/proc/sys/}. To enable IPv4 forwarding, it can be
15406 (service sysctl-service-type
15407 (sysctl-configuration
15408 (settings '(("net.ipv4.ip_forward" . "1")))))
15412 @deftp {Data Type} sysctl-configuration
15413 The data type representing the configuration of @command{sysctl}.
15416 @item @code{sysctl} (default: @code{(file-append procps "/sbin/sysctl"})
15417 The @command{sysctl} executable to use.
15419 @item @code{settings} (default: @code{'()})
15420 An association list specifies kernel parameters and their values.
15425 @subsubheading Lirc Service
15427 The @code{(gnu services lirc)} module provides the following service.
15429 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
15430 [#:device #f] [#:driver #f] [#:config-file #f] @
15431 [#:extra-options '()]
15432 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
15433 decodes infrared signals from remote controls.
15435 Optionally, @var{device}, @var{driver} and @var{config-file}
15436 (configuration file name) may be specified. See @command{lircd} manual
15439 Finally, @var{extra-options} is a list of additional command-line options
15440 passed to @command{lircd}.
15444 @subsubheading Spice Service
15446 The @code{(gnu services spice)} module provides the following service.
15448 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
15449 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
15450 that enables sharing the clipboard with a vm and setting the guest display
15451 resolution when the graphical console window resizes.
15454 @subsubsection Dictionary Services
15456 The @code{(gnu services dict)} module provides the following service:
15458 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
15459 Return a service that runs the @command{dicod} daemon, an implementation
15460 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
15462 The optional @var{config} argument specifies the configuration for
15463 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
15464 default it serves the GNU Collaborative International Dictonary of English.
15466 You can add @command{open localhost} to your @file{~/.dico} file to make
15467 @code{localhost} the default server for @command{dico} client
15468 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
15471 @deftp {Data Type} dicod-configuration
15472 Data type representing the configuration of dicod.
15475 @item @code{dico} (default: @var{dico})
15476 Package object of the GNU Dico dictionary server.
15478 @item @code{interfaces} (default: @var{'("localhost")})
15479 This is the list of IP addresses and ports and possibly socket file
15480 names to listen to (@pxref{Server Settings, @code{listen} directive,,
15481 dico, GNU Dico Manual}).
15483 @item @code{handlers} (default: @var{'()})
15484 List of @code{<dicod-handler>} objects denoting handlers (module instances).
15486 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
15487 List of @code{<dicod-database>} objects denoting dictionaries to be served.
15491 @deftp {Data Type} dicod-handler
15492 Data type representing a dictionary handler (module instance).
15496 Name of the handler (module instance).
15498 @item @code{module} (default: @var{#f})
15499 Name of the dicod module of the handler (instance). If it is @code{#f},
15500 the module has the same name as the handler.
15501 (@pxref{Modules,,, dico, GNU Dico Manual}).
15503 @item @code{options}
15504 List of strings or gexps representing the arguments for the module handler
15508 @deftp {Data Type} dicod-database
15509 Data type representing a dictionary database.
15513 Name of the database, will be used in DICT commands.
15515 @item @code{handler}
15516 Name of the dicod handler (module instance) used by this database
15517 (@pxref{Handlers,,, dico, GNU Dico Manual}).
15519 @item @code{complex?} (default: @var{#f})
15520 Whether the database configuration complex. The complex configuration
15521 will need a corresponding @code{<dicod-handler>} object, otherwise not.
15523 @item @code{options}
15524 List of strings or gexps representing the arguments for the database
15525 (@pxref{Databases,,, dico, GNU Dico Manual}).
15529 @defvr {Scheme Variable} %dicod-database:gcide
15530 A @code{<dicod-database>} object serving the GNU Collaborative International
15531 Dictionary of English using the @code{gcide} package.
15534 The following is an example @code{dicod-service} configuration.
15537 (dicod-service #:config
15538 (dicod-configuration
15539 (handlers (list (dicod-handler
15543 (list #~(string-append "dbdir=" #$wordnet))))))
15544 (databases (list (dicod-database
15547 (handler "wordnet")
15548 (options '("database=wn")))
15549 %dicod-database:gcide))))
15552 @subsubsection Version Control
15554 The @code{(gnu services version-control)} module provides the following services:
15556 @subsubheading Git daemon service
15558 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
15560 Return a service that runs @command{git daemon}, a simple TCP server to
15561 expose repositories over the Git protocol for anonymous access.
15563 The optional @var{config} argument should be a
15564 @code{<git-daemon-configuration>} object, by default it allows read-only
15565 access to exported@footnote{By creating the magic file
15566 "git-daemon-export-ok" in the repository directory.} repositories under
15571 @deftp {Data Type} git-daemon-configuration
15572 Data type representing the configuration for @code{git-daemon-service}.
15575 @item @code{package} (default: @var{git})
15576 Package object of the Git distributed version control system.
15578 @item @code{export-all?} (default: @var{#f})
15579 Whether to allow access for all Git repositories, even if they do not
15580 have the @file{git-daemon-export-ok} file.
15582 @item @code{base-path} (default: @file{/srv/git})
15583 Whether to remap all the path requests as relative to the given path.
15584 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
15585 then if you later try to pull @code{git://example.com/hello.git}, git
15586 daemon will interpret the path as @code{/srv/git/hello.git}.
15588 @item @code{user-path} (default: @var{#f})
15589 Whether to allow @code{~user} notation to be used in requests. When
15590 specified with empty string, requests to @code{git://host/~alice/foo} is
15591 taken as a request to access @code{foo} repository in the home directory
15592 of user @code{alice}. If @var{(user-path "path")} is specified, the
15593 same request is taken as a request to access @code{path/foo} repository
15594 in the home directory of user @code{alice}.
15596 @item @code{listen} (default: @var{'()})
15597 Whether to listen on specific IP addresses or hostnames, defaults to
15600 @item @code{port} (default: @var{#f})
15601 Whether to listen on an alternative port, which defaults to 9418.
15603 @item @code{whitelist} (default: @var{'()})
15604 If not empty, only allow access to this list of directories.
15606 @item @code{extra-options} (default: @var{'()})
15607 Extra options will be passed to @code{git daemon}, please run
15608 @command{man git-daemon} for more information.
15613 @node Setuid Programs
15614 @subsection Setuid Programs
15616 @cindex setuid programs
15617 Some programs need to run with ``root'' privileges, even when they are
15618 launched by unprivileged users. A notorious example is the
15619 @command{passwd} program, which users can run to change their
15620 password, and which needs to access the @file{/etc/passwd} and
15621 @file{/etc/shadow} files---something normally restricted to root, for
15622 obvious security reasons. To address that, these executables are
15623 @dfn{setuid-root}, meaning that they always run with root privileges
15624 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
15625 for more info about the setuid mechanism.)
15627 The store itself @emph{cannot} contain setuid programs: that would be a
15628 security issue since any user on the system can write derivations that
15629 populate the store (@pxref{The Store}). Thus, a different mechanism is
15630 used: instead of changing the setuid bit directly on files that are in
15631 the store, we let the system administrator @emph{declare} which programs
15632 should be setuid root.
15634 The @code{setuid-programs} field of an @code{operating-system}
15635 declaration contains a list of G-expressions denoting the names of
15636 programs to be setuid-root (@pxref{Using the Configuration System}).
15637 For instance, the @command{passwd} program, which is part of the Shadow
15638 package, can be designated by this G-expression (@pxref{G-Expressions}):
15641 #~(string-append #$shadow "/bin/passwd")
15644 A default set of setuid programs is defined by the
15645 @code{%setuid-programs} variable of the @code{(gnu system)} module.
15647 @defvr {Scheme Variable} %setuid-programs
15648 A list of G-expressions denoting common programs that are setuid-root.
15650 The list includes commands such as @command{passwd}, @command{ping},
15651 @command{su}, and @command{sudo}.
15654 Under the hood, the actual setuid programs are created in the
15655 @file{/run/setuid-programs} directory at system activation time. The
15656 files in this directory refer to the ``real'' binaries, which are in the
15659 @node X.509 Certificates
15660 @subsection X.509 Certificates
15662 @cindex HTTPS, certificates
15663 @cindex X.509 certificates
15665 Web servers available over HTTPS (that is, HTTP over the transport-layer
15666 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
15667 that the client can then use to @emph{authenticate} the server. To do
15668 that, clients verify that the server's certificate is signed by a
15669 so-called @dfn{certificate authority} (CA). But to verify the CA's
15670 signature, clients must have first acquired the CA's certificate.
15672 Web browsers such as GNU@tie{}IceCat include their own set of CA
15673 certificates, such that they are able to verify CA signatures
15676 However, most other programs that can talk HTTPS---@command{wget},
15677 @command{git}, @command{w3m}, etc.---need to be told where CA
15678 certificates can be found.
15680 @cindex @code{nss-certs}
15681 In GuixSD, this is done by adding a package that provides certificates
15682 to the @code{packages} field of the @code{operating-system} declaration
15683 (@pxref{operating-system Reference}). GuixSD includes one such package,
15684 @code{nss-certs}, which is a set of CA certificates provided as part of
15685 Mozilla's Network Security Services.
15687 Note that it is @emph{not} part of @var{%base-packages}, so you need to
15688 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
15689 most applications and libraries look for certificates by default, points
15690 to the certificates installed globally.
15692 Unprivileged users, including users of Guix on a foreign distro,
15693 can also install their own certificate package in
15694 their profile. A number of environment variables need to be defined so
15695 that applications and libraries know where to find them. Namely, the
15696 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
15697 variables. Some applications add their own environment variables; for
15698 instance, the Git version control system honors the certificate bundle
15699 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
15700 would typically run something like:
15703 $ guix package -i nss-certs
15704 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
15705 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15706 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
15709 As another example, R requires the @code{CURL_CA_BUNDLE} environment
15710 variable to point to a certificate bundle, so you would have to run
15711 something like this:
15714 $ guix package -i nss-certs
15715 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
15718 For other applications you may want to look up the required environment
15719 variable in the relevant documentation.
15722 @node Name Service Switch
15723 @subsection Name Service Switch
15725 @cindex name service switch
15727 The @code{(gnu system nss)} module provides bindings to the
15728 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
15729 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
15730 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
15731 extended with new ``name'' lookup methods for system databases, which
15732 includes host names, service names, user accounts, and more (@pxref{Name
15733 Service Switch, System Databases and Name Service Switch,, libc, The GNU
15734 C Library Reference Manual}).
15736 The NSS configuration specifies, for each system database, which lookup
15737 method is to be used, and how the various methods are chained
15738 together---for instance, under which circumstances NSS should try the
15739 next method in the list. The NSS configuration is given in the
15740 @code{name-service-switch} field of @code{operating-system} declarations
15741 (@pxref{operating-system Reference, @code{name-service-switch}}).
15744 @cindex .local, host name lookup
15745 As an example, the declaration below configures the NSS to use the
15746 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15747 back-end}, which supports host name lookups over multicast DNS (mDNS)
15748 for host names ending in @code{.local}:
15751 (name-service-switch
15752 (hosts (list %files ;first, check /etc/hosts
15754 ;; If the above did not succeed, try
15755 ;; with 'mdns_minimal'.
15757 (name "mdns_minimal")
15759 ;; 'mdns_minimal' is authoritative for
15760 ;; '.local'. When it returns "not found",
15761 ;; no need to try the next methods.
15762 (reaction (lookup-specification
15763 (not-found => return))))
15765 ;; Then fall back to DNS.
15769 ;; Finally, try with the "full" 'mdns'.
15774 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15775 contains this configuration, so you will not have to type it if all you
15776 want is to have @code{.local} host lookup working.
15778 Note that, in this case, in addition to setting the
15779 @code{name-service-switch} of the @code{operating-system} declaration,
15780 you also need to use @code{avahi-service} (@pxref{Networking Services,
15781 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15782 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15783 to the name service cache daemon (@pxref{Base Services,
15784 @code{nscd-service}}).
15786 For convenience, the following variables provide typical NSS
15789 @defvr {Scheme Variable} %default-nss
15790 This is the default name service switch configuration, a
15791 @code{name-service-switch} object.
15794 @defvr {Scheme Variable} %mdns-host-lookup-nss
15795 This is the name service switch configuration with support for host name
15796 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
15799 The reference for name service switch configuration is given below. It
15800 is a direct mapping of the configuration file format of the C library , so
15801 please refer to the C library manual for more information (@pxref{NSS
15802 Configuration File,,, libc, The GNU C Library Reference Manual}).
15803 Compared to the configuration file format of libc NSS, it has the advantage
15804 not only of adding this warm parenthetic feel that we like, but also
15805 static checks: you will know about syntax errors and typos as soon as you
15806 run @command{guix system}.
15808 @deftp {Data Type} name-service-switch
15810 This is the data type representation the configuration of libc's name
15811 service switch (NSS). Each field below represents one of the supported
15828 The system databases handled by the NSS. Each of these fields must be a
15829 list of @code{<name-service>} objects (see below).
15833 @deftp {Data Type} name-service
15835 This is the data type representing an actual name service and the
15836 associated lookup action.
15840 A string denoting the name service (@pxref{Services in the NSS
15841 configuration,,, libc, The GNU C Library Reference Manual}).
15843 Note that name services listed here must be visible to nscd. This is
15844 achieved by passing the @code{#:name-services} argument to
15845 @code{nscd-service} the list of packages providing the needed name
15846 services (@pxref{Base Services, @code{nscd-service}}).
15849 An action specified using the @code{lookup-specification} macro
15850 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15851 Reference Manual}). For example:
15854 (lookup-specification (unavailable => continue)
15855 (success => return))
15860 @node Initial RAM Disk
15861 @subsection Initial RAM Disk
15864 @cindex initial RAM disk
15865 For bootstrapping purposes, the Linux-Libre kernel is passed an
15866 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15867 root file system as well as an initialization script. The latter is
15868 responsible for mounting the real root file system, and for loading any
15869 kernel modules that may be needed to achieve that.
15871 The @code{initrd} field of an @code{operating-system} declaration allows
15872 you to specify which initrd you would like to use. The @code{(gnu
15873 system linux-initrd)} module provides three ways to build an initrd: the
15874 high-level @code{base-initrd} procedure and the low-level
15875 @code{raw-initrd} and @code{expression->initrd} procedures.
15877 The @code{base-initrd} procedure is intended to cover most common uses.
15878 For example, if you want to add a bunch of kernel modules to be loaded
15879 at boot time, you can define the @code{initrd} field of the operating
15880 system declaration like this:
15883 (initrd (lambda (file-systems . rest)
15884 ;; Create a standard initrd that has modules "foo.ko"
15885 ;; and "bar.ko", as well as their dependencies, in
15886 ;; addition to the modules available by default.
15887 (apply base-initrd file-systems
15888 #:extra-modules '("foo" "bar")
15892 The @code{base-initrd} procedure also handles common use cases that
15893 involves using the system as a QEMU guest, or as a ``live'' system with
15894 volatile root file system.
15896 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15897 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15898 such as trying to guess which kernel modules and packages should be included
15899 to the initrd. An example use of @code{raw-initrd} is when a user has
15900 a custom Linux kernel configuration and default kernel modules included by
15901 @code{base-initrd} are not available.
15903 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15904 honors several options passed on the Linux kernel command line
15905 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15906 @code{-append} option of QEMU), notably:
15909 @item --load=@var{boot}
15910 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15911 program, once it has mounted the root file system.
15913 GuixSD uses this option to yield control to a boot program that runs the
15914 service activation programs and then spawns the GNU@tie{}Shepherd, the
15915 initialization system.
15917 @item --root=@var{root}
15918 Mount @var{root} as the root file system. @var{root} can be a
15919 device name like @code{/dev/sda1}, a partition label, or a partition
15922 @item --system=@var{system}
15923 Have @file{/run/booted-system} and @file{/run/current-system} point to
15926 @item modprobe.blacklist=@var{modules}@dots{}
15927 @cindex module, black-listing
15928 @cindex black list, of kernel modules
15929 Instruct the initial RAM disk as well as the @command{modprobe} command
15930 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15931 must be a comma-separated list of module names---e.g.,
15932 @code{usbkbd,9pnet}.
15935 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15936 tries to load kernel modules and to mount the root file system. Our
15937 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15938 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15939 Manual}, for more information on Guile's REPL.
15943 Now that you know all the features that initial RAM disks produced by
15944 @code{base-initrd} and @code{raw-initrd} provide,
15945 here is how to use it and customize it further.
15948 @cindex initial RAM disk
15949 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15950 [#:linux-modules '()] [#:mapped-devices '()] @
15951 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15952 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15953 a list of file systems to be mounted by the initrd, possibly in addition to
15954 the root file system specified on the kernel command line via @code{--root}.
15955 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15956 @var{mapped-devices} is a list of device mappings to realize before
15957 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15958 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15959 include @code{e2fsck/static} or other packages needed by the initrd to check
15962 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15963 parameters. When @var{virtio?} is true, load additional modules so that the
15964 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15966 When @var{volatile-root?} is true, the root file system is writable but any changes
15970 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15971 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15972 [#:virtio? #t] [#:extra-modules '()]
15973 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15974 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15975 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15976 also behaves as in @code{raw-initrd}.
15978 When @var{virtio?} is true, load additional modules so that the
15979 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15981 The initrd is automatically populated with all the kernel modules necessary
15982 for @var{file-systems} and for the given options. However, additional kernel
15983 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15984 loaded at boot time in the order in which they appear.
15987 Needless to say, the initrds we produce and use embed a
15988 statically-linked Guile, and the initialization program is a Guile
15989 program. That gives a lot of flexibility. The
15990 @code{expression->initrd} procedure builds such an initrd, given the
15991 program to run in that initrd.
15993 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15994 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15995 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15996 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15997 upon booting. All the derivations referenced by @var{exp} are
15998 automatically copied to the initrd.
16001 @node Bootloader Configuration
16002 @subsection Bootloader Configuration
16005 @cindex boot loader
16007 The operating system supports multiple bootloaders. The bootloader is
16008 configured using @code{bootloader-configuration} declaration. All the
16009 fields of this structure are bootloader agnostic except for one field,
16010 @code{bootloader} that indicates the bootloader to be configured and
16013 Some of the bootloaders do not honor every field of
16014 @code{bootloader-configuration}. For instance, the extlinux
16015 bootloader does not support themes and thus ignores the @code{theme}
16018 @deftp {Data Type} bootloader-configuration
16019 The type of a bootloader configuration declaration.
16023 @item @code{bootloader}
16024 @cindex EFI, bootloader
16025 @cindex UEFI, bootloader
16026 @cindex BIOS, bootloader
16027 The bootloader to use, as a @code{bootloader} object. For now
16028 @code{grub-bootloader}, @code{grub-efi-bootloader},
16029 @code{extlinux-bootloader} and @code{u-boot-bootloader} are supported.
16030 @code{grub-efi-bootloader} allows to boot on modern systems using the
16031 @dfn{Unified Extensible Firmware Interface} (UEFI).
16033 Available bootloaders are described in @code{(gnu bootloader @dots{})}
16036 @item @code{device}
16037 This is a string denoting the boot device. It must be a device name
16038 understood by the bootloader @command{installer} command, such as
16039 @code{/dev/sda} or @code{(hd0)} (for GRUB, @pxref{Invoking grub-install,,, grub,
16042 @item @code{menu-entries} (default: @code{()})
16043 A possibly empty list of @code{menu-entry} objects (see below), denoting
16044 entries to appear in the bootloader menu, in addition to the current
16045 system entry and the entry pointing to previous system generations.
16048 @item @code{default-entry} (default: @code{0})
16049 The index of the default boot menu entry. Index 0 is for the entry of the
16052 @item @code{timeout} (default: @code{5})
16053 The number of seconds to wait for keyboard input before booting. Set to
16054 0 to boot immediately, and to -1 to wait indefinitely.
16056 @item @code{theme} (default: @var{#f})
16057 The bootloader theme object describing the theme to use. If no theme
16058 is provided, some bootloaders might use a default theme, that's true
16061 @item @code{terminal-outputs} (default: @code{'gfxterm})
16062 The output terminals used for the bootloader boot menu, as a list of
16063 symbols. GRUB accepts the values: @code{console}, @code{serial},
16064 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text},
16065 @code{mda_text}, @code{morse}, and @code{pkmodem}. This field
16066 corresponds to the GRUB variable GRUB_TERMINAL_OUTPUT (@pxref{Simple
16067 configuration,,, grub,GNU GRUB manual}).
16069 @item @code{terminal-inputs} (default: @code{'()})
16070 The input terminals used for the bootloader boot menu, as a list of
16071 symbols. For GRUB, the default is the native platform terminal as
16072 determined at run-time. GRUB accepts the values: @code{console},
16073 @code{serial}, @code{serial_@{0-3@}}, @code{at_keyboard}, and
16074 @code{usb_keyboard}. This field corresponds to the GRUB variable
16075 GRUB_TERMINAL_INPUT (@pxref{Simple configuration,,, grub,GNU GRUB
16078 @item @code{serial-unit} (default: @code{#f})
16079 The serial unit used by the bootloader, as an integer from 0 to 3.
16080 For GRUB it is choosen at run-time; currently GRUB chooses 0, which
16081 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16083 @item @code{serial-speed} (default: @code{#f})
16084 The speed of the serial interface, as an integer. For GRUB, the
16085 default value is chosen at run-time; currently GRUB chooses
16086 9600@tie{}bps (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
16093 Should you want to list additional boot menu entries @i{via} the
16094 @code{menu-entries} field above, you will need to create them with the
16095 @code{menu-entry} form. For example, imagine you want to be able to
16096 boot another distro (hard to imagine!), you can define a menu entry
16101 (label "The Other Distro")
16102 (linux "/boot/old/vmlinux-2.6.32")
16103 (linux-arguments '("root=/dev/sda2"))
16104 (initrd "/boot/old/initrd"))
16109 @deftp {Data Type} menu-entry
16110 The type of an entry in the bootloader menu.
16115 The label to show in the menu---e.g., @code{"GNU"}.
16118 The Linux kernel image to boot, for example:
16121 (file-append linux-libre "/bzImage")
16124 For GRUB, it is also possible to specify a device explicitly in the
16125 file path using GRUB's device naming convention (@pxref{Naming
16126 convention,,, grub, GNU GRUB manual}), for example:
16129 "(hd0,msdos1)/boot/vmlinuz"
16132 If the device is specified explicitly as above, then the @code{device}
16133 field is ignored entirely.
16135 @item @code{linux-arguments} (default: @code{()})
16136 The list of extra Linux kernel command-line arguments---e.g.,
16137 @code{("console=ttyS0")}.
16139 @item @code{initrd}
16140 A G-Expression or string denoting the file name of the initial RAM disk
16141 to use (@pxref{G-Expressions}).
16142 @item @code{device} (default: @code{#f})
16143 The device where the kernel and initrd are to be found---i.e., for GRUB,
16144 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
16146 This may be a file system label (a string), a file system UUID (a
16147 bytevector, @pxref{File Systems}), or @code{#f}, in which case
16148 the bootloader will search the device containing the file specified by
16149 the @code{linux} field (@pxref{search,,, grub, GNU GRUB manual}). It
16150 must @emph{not} be an OS device name such as @file{/dev/sda1}.
16155 @c FIXME: Write documentation once it's stable.
16156 Fow now only GRUB has theme support. GRUB themes are created using
16157 the @code{grub-theme} form, which is not documented yet.
16159 @defvr {Scheme Variable} %default-theme
16160 This is the default GRUB theme used by the operating system if no
16161 @code{theme} field is specified in @code{bootloader-configuration}
16164 It comes with a fancy background image displaying the GNU and Guix
16169 @node Invoking guix system
16170 @subsection Invoking @code{guix system}
16172 Once you have written an operating system declaration as seen in the
16173 previous section, it can be @dfn{instantiated} using the @command{guix
16174 system} command. The synopsis is:
16177 guix system @var{options}@dots{} @var{action} @var{file}
16180 @var{file} must be the name of a file containing an
16181 @code{operating-system} declaration. @var{action} specifies how the
16182 operating system is instantiated. Currently the following values are
16187 Build the operating system described in @var{file}, activate it, and
16188 switch to it@footnote{This action (and the related actions
16189 @code{switch-generation} and @code{roll-back}) are usable only on
16190 systems already running GuixSD.}.
16192 This effects all the configuration specified in @var{file}: user
16193 accounts, system services, global package list, setuid programs, etc.
16194 The command starts system services specified in @var{file} that are not
16195 currently running; if a service is currently running, it does not
16196 attempt to upgrade it since this would not be possible without stopping it
16199 This command creates a new generation whose number is one greater than
16200 the current generation (as reported by @command{guix system
16201 list-generations}). If that generation already exists, it will be
16202 overwritten. This behavior mirrors that of @command{guix package}
16203 (@pxref{Invoking guix package}).
16205 It also adds a bootloader menu entry for the new OS configuration,
16206 ---unless @option{--no-bootloader} is passed. For GRUB, it moves
16207 entries for older configurations to a submenu, allowing you to choose
16208 an older system generation at boot time should you need it.
16211 @c The paragraph below refers to the problem discussed at
16212 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
16213 It is highly recommended to run @command{guix pull} once before you run
16214 @command{guix system reconfigure} for the first time (@pxref{Invoking
16215 guix pull}). Failing to do that you would see an older version of Guix
16216 once @command{reconfigure} has completed.
16219 @item switch-generation
16220 @cindex generations
16221 Switch to an existing system generation. This action atomically
16222 switches the system profile to the specified system generation. It
16223 also rearranges the system's existing bootloader menu entries. It
16224 makes the menu entry for the specified system generation the default,
16225 and it moves the entries for the other generatiors to a submenu, if
16226 supported by the bootloader being used. The next time the system
16227 boots, it will use the specified system generation.
16229 The bootloader itself is not being reinstalled when using this
16230 command. Thus, the installed bootloader is used with an updated
16231 configuration file.
16233 The target generation can be specified explicitly by its generation
16234 number. For example, the following invocation would switch to system
16238 guix system switch-generation 7
16241 The target generation can also be specified relative to the current
16242 generation with the form @code{+N} or @code{-N}, where @code{+3} means
16243 ``3 generations ahead of the current generation,'' and @code{-1} means
16244 ``1 generation prior to the current generation.'' When specifying a
16245 negative value such as @code{-1}, you must precede it with @code{--} to
16246 prevent it from being parsed as an option. For example:
16249 guix system switch-generation -- -1
16252 Currently, the effect of invoking this action is @emph{only} to switch
16253 the system profile to an existing generation and rearrange the
16254 bootloader menu entries. To actually start using the target system
16255 generation, you must reboot after running this action. In the future,
16256 it will be updated to do the same things as @command{reconfigure},
16257 like activating and deactivating services.
16259 This action will fail if the specified generation does not exist.
16262 @cindex rolling back
16263 Switch to the preceding system generation. The next time the system
16264 boots, it will use the preceding system generation. This is the inverse
16265 of @command{reconfigure}, and it is exactly the same as invoking
16266 @command{switch-generation} with an argument of @code{-1}.
16268 Currently, as with @command{switch-generation}, you must reboot after
16269 running this action to actually start using the preceding system
16273 Build the derivation of the operating system, which includes all the
16274 configuration files and programs needed to boot and run the system.
16275 This action does not actually install anything.
16278 Populate the given directory with all the files necessary to run the
16279 operating system specified in @var{file}. This is useful for first-time
16280 installations of GuixSD. For instance:
16283 guix system init my-os-config.scm /mnt
16286 copies to @file{/mnt} all the store items required by the configuration
16287 specified in @file{my-os-config.scm}. This includes configuration
16288 files, packages, and so on. It also creates other essential files
16289 needed for the system to operate correctly---e.g., the @file{/etc},
16290 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
16292 This command also installs bootloader on the device specified in
16293 @file{my-os-config}, unless the @option{--no-bootloader} option was
16297 @cindex virtual machine
16299 @anchor{guix system vm}
16300 Build a virtual machine that contains the operating system declared in
16301 @var{file}, and return a script to run that virtual machine (VM).
16302 Arguments given to the script are passed to QEMU.
16304 The VM shares its store with the host system.
16306 Additional file systems can be shared between the host and the VM using
16307 the @code{--share} and @code{--expose} command-line options: the former
16308 specifies a directory to be shared with write access, while the latter
16309 provides read-only access to the shared directory.
16311 The example below creates a VM in which the user's home directory is
16312 accessible read-only, and where the @file{/exchange} directory is a
16313 read-write mapping of @file{$HOME/tmp} on the host:
16316 guix system vm my-config.scm \
16317 --expose=$HOME --share=$HOME/tmp=/exchange
16320 On GNU/Linux, the default is to boot directly to the kernel; this has
16321 the advantage of requiring only a very tiny root disk image since the
16322 store of the host can then be mounted.
16324 The @code{--full-boot} option forces a complete boot sequence, starting
16325 with the bootloader. This requires more disk space since a root image
16326 containing at least the kernel, initrd, and bootloader data files must
16327 be created. The @code{--image-size} option can be used to specify the
16332 Return a virtual machine or disk image of the operating system declared
16333 in @var{file} that stands alone. By default, @command{guix system}
16334 estimates the size of the image needed to store the system, but you can
16335 use the @option{--image-size} option to specify a value.
16337 You can specify the root file system type by using the
16338 @option{--file-system-type} option. It defaults to @code{ext4}.
16340 When using @code{vm-image}, the returned image is in qcow2 format, which
16341 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
16342 for more information on how to run the image in a virtual machine.
16344 When using @code{disk-image}, a raw disk image is produced; it can be
16345 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
16346 the device corresponding to a USB stick, one can copy the image to it
16347 using the following command:
16350 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
16354 Return a script to run the operating system declared in @var{file}
16355 within a container. Containers are a set of lightweight isolation
16356 mechanisms provided by the kernel Linux-libre. Containers are
16357 substantially less resource-demanding than full virtual machines since
16358 the kernel, shared objects, and other resources can be shared with the
16359 host system; this also means they provide thinner isolation.
16361 Currently, the script must be run as root in order to support more than
16362 a single user and group. The container shares its store with the host
16365 As with the @code{vm} action (@pxref{guix system vm}), additional file
16366 systems to be shared between the host and container can be specified
16367 using the @option{--share} and @option{--expose} options:
16370 guix system container my-config.scm \
16371 --expose=$HOME --share=$HOME/tmp=/exchange
16375 This option requires Linux-libre 3.19 or newer.
16380 @var{options} can contain any of the common build options (@pxref{Common
16381 Build Options}). In addition, @var{options} can contain one of the
16385 @item --system=@var{system}
16386 @itemx -s @var{system}
16387 Attempt to build for @var{system} instead of the host system type.
16388 This works as per @command{guix build} (@pxref{Invoking guix build}).
16392 Return the derivation file name of the given operating system without
16395 @item --file-system-type=@var{type}
16396 @itemx -t @var{type}
16397 For the @code{disk-image} action, create a file system of the given
16398 @var{type} on the image.
16400 When this option is omitted, @command{guix system} uses @code{ext4}.
16402 @cindex ISO-9660 format
16403 @cindex CD image format
16404 @cindex DVD image format
16405 @code{--file-system-type=iso9660} produces an ISO-9660 image, suitable
16406 for burning on CDs and DVDs.
16408 @item --image-size=@var{size}
16409 For the @code{vm-image} and @code{disk-image} actions, create an image
16410 of the given @var{size}. @var{size} may be a number of bytes, or it may
16411 include a unit as a suffix (@pxref{Block size, size specifications,,
16412 coreutils, GNU Coreutils}).
16414 When this option is omitted, @command{guix system} computes an estimate
16415 of the image size as a function of the size of the system declared in
16418 @item --root=@var{file}
16419 @itemx -r @var{file}
16420 Make @var{file} a symlink to the result, and register it as a garbage
16423 @item --on-error=@var{strategy}
16424 Apply @var{strategy} when an error occurs when reading @var{file}.
16425 @var{strategy} may be one of the following:
16428 @item nothing-special
16429 Report the error concisely and exit. This is the default strategy.
16432 Likewise, but also display a backtrace.
16435 Report the error and enter Guile's debugger. From there, you can run
16436 commands such as @code{,bt} to get a backtrace, @code{,locals} to
16437 display local variable values, and more generally inspect the state of the
16438 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
16439 a list of available debugging commands.
16444 All the actions above, except @code{build} and @code{init},
16445 can use KVM support in the Linux-libre kernel. Specifically, if the
16446 machine has hardware virtualization support, the corresponding
16447 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
16448 must exist and be readable and writable by the user and by the
16449 build users of the daemon (@pxref{Build Environment Setup}).
16452 Once you have built, configured, re-configured, and re-re-configured
16453 your GuixSD installation, you may find it useful to list the operating
16454 system generations available on disk---and that you can choose from the
16455 bootloader boot menu:
16459 @item list-generations
16460 List a summary of each generation of the operating system available on
16461 disk, in a human-readable way. This is similar to the
16462 @option{--list-generations} option of @command{guix package}
16463 (@pxref{Invoking guix package}).
16465 Optionally, one can specify a pattern, with the same syntax that is used
16466 in @command{guix package --list-generations}, to restrict the list of
16467 generations displayed. For instance, the following command displays
16468 generations that are up to 10 days old:
16471 $ guix system list-generations 10d
16476 The @command{guix system} command has even more to offer! The following
16477 sub-commands allow you to visualize how your system services relate to
16480 @anchor{system-extension-graph}
16483 @item extension-graph
16484 Emit in Dot/Graphviz format to standard output the @dfn{service
16485 extension graph} of the operating system defined in @var{file}
16486 (@pxref{Service Composition}, for more information on service
16492 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
16495 produces a PDF file showing the extension relations among services.
16497 @anchor{system-shepherd-graph}
16498 @item shepherd-graph
16499 Emit in Dot/Graphviz format to standard output the @dfn{dependency
16500 graph} of shepherd services of the operating system defined in
16501 @var{file}. @xref{Shepherd Services}, for more information and for an
16506 @node Running GuixSD in a VM
16507 @subsection Running GuixSD in a Virtual Machine
16509 @cindex virtual machine
16510 To run GuixSD in a virtual machine (VM), one can either use the
16511 pre-built GuixSD VM image distributed at
16512 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
16513 , or build their own virtual machine image using @command{guix system
16514 vm-image} (@pxref{Invoking guix system}). The returned image is in
16515 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
16519 If you built your own image, you must copy it out of the store
16520 (@pxref{The Store}) and give yourself permission to write to the copy
16521 before you can use it. When invoking QEMU, you must choose a system
16522 emulator that is suitable for your hardware platform. Here is a minimal
16523 QEMU invocation that will boot the result of @command{guix system
16524 vm-image} on x86_64 hardware:
16527 $ qemu-system-x86_64 \
16528 -net user -net nic,model=virtio \
16529 -enable-kvm -m 256 /tmp/qemu-image
16532 Here is what each of these options means:
16535 @item qemu-system-x86_64
16536 This specifies the hardware platform to emulate. This should match the
16540 Enable the unprivileged user-mode network stack. The guest OS can
16541 access the host but not vice versa. This is the simplest way to get the
16544 @item -net nic,model=virtio
16545 You must create a network interface of a given model. If you do not
16546 create a NIC, the boot will fail. Assuming your hardware platform is
16547 x86_64, you can get a list of available NIC models by running
16548 @command{qemu-system-x86_64 -net nic,model=help}.
16551 If your system has hardware virtualization extensions, enabling the
16552 virtual machine support (KVM) of the Linux kernel will make things run
16556 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
16557 which may be insufficient for some operations.
16559 @item /tmp/qemu-image
16560 The file name of the qcow2 image.
16563 The default @command{run-vm.sh} script that is returned by an invocation of
16564 @command{guix system vm} does not add a @command{-net user} flag by default.
16565 To get network access from within the vm add the @code{(dhcp-client-service)}
16566 to your system definition and start the VM using
16567 @command{`guix system vm config.scm` -net user}. An important caveat of using
16568 @command{-net user} for networking is that @command{ping} will not work, because
16569 it uses the ICMP protocol. You'll have to use a different command to check for
16570 network connectivity, for example @command{guix download}.
16572 @subsubsection Connecting Through SSH
16576 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
16577 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
16578 boot unsupervised. It requires you to type some characters to initialize the
16579 randomness generator. In addition you need to forward the SSH port, 22 by
16580 default, to the host. You can do this with
16583 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
16586 To connect to the VM you can run
16589 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
16592 The @command{-p} tells @command{ssh} the port you want to connect to.
16593 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
16594 every time you modify your @command{config.scm} file and the
16595 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
16596 connection to an unknown host every time you connect.
16598 @subsubsection Using @command{virt-viewer} with Spice
16600 As an alternative to the default @command{qemu} graphical client you can
16601 use the @command{remote-viewer} from the @command{virt-viewer} package. To
16602 connect pass the @command{-spice port=5930,disable-ticketing} flag to
16603 @command{qemu}. See previous section for further information on how to do this.
16605 Spice also allows you to do some nice stuff like share your clipboard with your
16606 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
16609 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
16610 -chardev spicevmc,name=vdagent,id=vdagent
16611 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
16612 name=com.redhat.spice.0
16615 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
16617 @node Defining Services
16618 @subsection Defining Services
16620 The previous sections show the available services and how one can combine
16621 them in an @code{operating-system} declaration. But how do we define
16622 them in the first place? And what is a service anyway?
16625 * Service Composition:: The model for composing services.
16626 * Service Types and Services:: Types and services.
16627 * Service Reference:: API reference.
16628 * Shepherd Services:: A particular type of service.
16631 @node Service Composition
16632 @subsubsection Service Composition
16636 Here we define a @dfn{service} as, broadly, something that extends the
16637 functionality of the operating system. Often a service is a process---a
16638 @dfn{daemon}---started when the system boots: a secure shell server, a
16639 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
16640 whose execution can be triggered by another daemon---e.g., an FTP server
16641 started by @command{inetd} or a D-Bus service activated by
16642 @command{dbus-daemon}. Occasionally, a service does not map to a
16643 daemon. For instance, the ``account'' service collects user accounts
16644 and makes sure they exist when the system runs; the ``udev'' service
16645 collects device management rules and makes them available to the eudev
16646 daemon; the @file{/etc} service populates the @file{/etc} directory
16649 @cindex service extensions
16650 GuixSD services are connected by @dfn{extensions}. For instance, the
16651 secure shell service @emph{extends} the Shepherd---the GuixSD
16652 initialization system, running as PID@tie{}1---by giving it the command
16653 lines to start and stop the secure shell daemon (@pxref{Networking
16654 Services, @code{lsh-service}}); the UPower service extends the D-Bus
16655 service by passing it its @file{.service} specification, and extends the
16656 udev service by passing it device management rules (@pxref{Desktop
16657 Services, @code{upower-service}}); the Guix daemon service extends the
16658 Shepherd by passing it the command lines to start and stop the daemon,
16659 and extends the account service by passing it a list of required build
16660 user accounts (@pxref{Base Services}).
16662 All in all, services and their ``extends'' relations form a directed
16663 acyclic graph (DAG). If we represent services as boxes and extensions
16664 as arrows, a typical system might provide something like this:
16666 @image{images/service-graph,,5in,Typical service extension graph.}
16668 @cindex system service
16669 At the bottom, we see the @dfn{system service}, which produces the
16670 directory containing everything to run and boot the system, as returned
16671 by the @command{guix system build} command. @xref{Service Reference},
16672 to learn about the other service types shown here.
16673 @xref{system-extension-graph, the @command{guix system extension-graph}
16674 command}, for information on how to generate this representation for a
16675 particular operating system definition.
16677 @cindex service types
16678 Technically, developers can define @dfn{service types} to express these
16679 relations. There can be any number of services of a given type on the
16680 system---for instance, a system running two instances of the GNU secure
16681 shell server (lsh) has two instances of @var{lsh-service-type}, with
16682 different parameters.
16684 The following section describes the programming interface for service
16685 types and services.
16687 @node Service Types and Services
16688 @subsubsection Service Types and Services
16690 A @dfn{service type} is a node in the DAG described above. Let us start
16691 with a simple example, the service type for the Guix build daemon
16692 (@pxref{Invoking guix-daemon}):
16695 (define guix-service-type
16699 (list (service-extension shepherd-root-service-type guix-shepherd-service)
16700 (service-extension account-service-type guix-accounts)
16701 (service-extension activation-service-type guix-activation)))
16702 (default-value (guix-configuration))))
16706 It defines three things:
16710 A name, whose sole purpose is to make inspection and debugging easier.
16713 A list of @dfn{service extensions}, where each extension designates the
16714 target service type and a procedure that, given the parameters of the
16715 service, returns a list of objects to extend the service of that type.
16717 Every service type has at least one service extension. The only
16718 exception is the @dfn{boot service type}, which is the ultimate service.
16721 Optionally, a default value for instances of this type.
16724 In this example, @var{guix-service-type} extends three services:
16727 @item shepherd-root-service-type
16728 The @var{guix-shepherd-service} procedure defines how the Shepherd
16729 service is extended. Namely, it returns a @code{<shepherd-service>}
16730 object that defines how @command{guix-daemon} is started and stopped
16731 (@pxref{Shepherd Services}).
16733 @item account-service-type
16734 This extension for this service is computed by @var{guix-accounts},
16735 which returns a list of @code{user-group} and @code{user-account}
16736 objects representing the build user accounts (@pxref{Invoking
16739 @item activation-service-type
16740 Here @var{guix-activation} is a procedure that returns a gexp, which is
16741 a code snippet to run at ``activation time''---e.g., when the service is
16745 A service of this type is instantiated like this:
16748 (service guix-service-type
16749 (guix-configuration
16751 (use-substitutes? #f)))
16754 The second argument to the @code{service} form is a value representing
16755 the parameters of this specific service instance.
16756 @xref{guix-configuration-type, @code{guix-configuration}}, for
16757 information about the @code{guix-configuration} data type. When the
16758 value is omitted, the default value specified by
16759 @code{guix-service-type} is used:
16762 (service guix-service-type)
16765 @var{guix-service-type} is quite simple because it extends other
16766 services but is not extensible itself.
16768 @c @subsubsubsection Extensible Service Types
16770 The service type for an @emph{extensible} service looks like this:
16773 (define udev-service-type
16774 (service-type (name 'udev)
16776 (list (service-extension shepherd-root-service-type
16777 udev-shepherd-service)))
16779 (compose concatenate) ;concatenate the list of rules
16780 (extend (lambda (config rules)
16782 (($ <udev-configuration> udev initial-rules)
16783 (udev-configuration
16784 (udev udev) ;the udev package to use
16785 (rules (append initial-rules rules)))))))))
16788 This is the service type for the
16789 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
16790 management daemon}. Compared to the previous example, in addition to an
16791 extension of @var{shepherd-root-service-type}, we see two new fields:
16795 This is the procedure to @dfn{compose} the list of extensions to
16796 services of this type.
16798 Services can extend the udev service by passing it lists of rules; we
16799 compose those extensions simply by concatenating them.
16802 This procedure defines how the value of the service is @dfn{extended} with
16803 the composition of the extensions.
16805 Udev extensions are composed into a list of rules, but the udev service
16806 value is itself a @code{<udev-configuration>} record. So here, we
16807 extend that record by appending the list of rules it contains to the
16808 list of contributed rules.
16811 There can be only one instance of an extensible service type such as
16812 @var{udev-service-type}. If there were more, the
16813 @code{service-extension} specifications would be ambiguous.
16815 Still here? The next section provides a reference of the programming
16816 interface for services.
16818 @node Service Reference
16819 @subsubsection Service Reference
16821 We have seen an overview of service types (@pxref{Service Types and
16822 Services}). This section provides a reference on how to manipulate
16823 services and service types. This interface is provided by the
16824 @code{(gnu services)} module.
16826 @deffn {Scheme Procedure} service @var{type} [@var{value}]
16827 Return a new service of @var{type}, a @code{<service-type>} object (see
16828 below.) @var{value} can be any object; it represents the parameters of
16829 this particular service instance.
16831 When @var{value} is omitted, the default value specified by @var{type}
16832 is used; if @var{type} does not specify a default value, an error is
16835 For instance, this:
16838 (service openssh-service-type)
16842 is equivalent to this:
16845 (service openssh-service-type
16846 (openssh-configuration))
16849 In both cases the result is an instance of @code{openssh-service-type}
16850 with the default configuration.
16853 @deffn {Scheme Procedure} service? @var{obj}
16854 Return true if @var{obj} is a service.
16857 @deffn {Scheme Procedure} service-kind @var{service}
16858 Return the type of @var{service}---i.e., a @code{<service-type>} object.
16861 @deffn {Scheme Procedure} service-value @var{service}
16862 Return the value associated with @var{service}. It represents its
16866 Here is an example of how a service is created and manipulated:
16870 (service nginx-service-type
16871 (nginx-configuration
16873 (log-directory log-directory)
16874 (run-directory run-directory)
16875 (file config-file))))
16880 (eq? (service-kind s) nginx-service-type)
16884 The @code{modify-services} form provides a handy way to change the
16885 parameters of some of the services of a list such as
16886 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
16887 evaluates to a list of services. Of course, you could always use
16888 standard list combinators such as @code{map} and @code{fold} to do that
16889 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
16890 @code{modify-services} simply provides a more concise form for this
16893 @deffn {Scheme Syntax} modify-services @var{services} @
16894 (@var{type} @var{variable} => @var{body}) @dots{}
16896 Modify the services listed in @var{services} according to the given
16897 clauses. Each clause has the form:
16900 (@var{type} @var{variable} => @var{body})
16903 where @var{type} is a service type---e.g.,
16904 @code{guix-service-type}---and @var{variable} is an identifier that is
16905 bound within the @var{body} to the service parameters---e.g., a
16906 @code{guix-configuration} instance---of the original service of that
16909 The @var{body} should evaluate to the new service parameters, which will
16910 be used to configure the new service. This new service will replace the
16911 original in the resulting list. Because a service's service parameters
16912 are created using @code{define-record-type*}, you can write a succinct
16913 @var{body} that evaluates to the new service parameters by using the
16914 @code{inherit} feature that @code{define-record-type*} provides.
16916 @xref{Using the Configuration System}, for example usage.
16920 Next comes the programming interface for service types. This is
16921 something you want to know when writing new service definitions, but not
16922 necessarily when simply looking for ways to customize your
16923 @code{operating-system} declaration.
16925 @deftp {Data Type} service-type
16926 @cindex service type
16927 This is the representation of a @dfn{service type} (@pxref{Service Types
16932 This is a symbol, used only to simplify inspection and debugging.
16934 @item @code{extensions}
16935 A non-empty list of @code{<service-extension>} objects (see below).
16937 @item @code{compose} (default: @code{#f})
16938 If this is @code{#f}, then the service type denotes services that cannot
16939 be extended---i.e., services that do not receive ``values'' from other
16942 Otherwise, it must be a one-argument procedure. The procedure is called
16943 by @code{fold-services} and is passed a list of values collected from
16944 extensions. It must return a value that is a valid parameter value for
16945 the service instance.
16947 @item @code{extend} (default: @code{#f})
16948 If this is @code{#f}, services of this type cannot be extended.
16950 Otherwise, it must be a two-argument procedure: @code{fold-services}
16951 calls it, passing it the initial value of the service as the first argument
16952 and the result of applying @code{compose} to the extension values as the
16956 @xref{Service Types and Services}, for examples.
16959 @deffn {Scheme Procedure} service-extension @var{target-type} @
16961 Return a new extension for services of type @var{target-type}.
16962 @var{compute} must be a one-argument procedure: @code{fold-services}
16963 calls it, passing it the value associated with the service that provides
16964 the extension; it must return a valid value for the target service.
16967 @deffn {Scheme Procedure} service-extension? @var{obj}
16968 Return true if @var{obj} is a service extension.
16971 Occasionally, you might want to simply extend an existing service. This
16972 involves creating a new service type and specifying the extension of
16973 interest, which can be verbose; the @code{simple-service} procedure
16974 provides a shorthand for this.
16976 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16977 Return a service that extends @var{target} with @var{value}. This works
16978 by creating a singleton service type @var{name}, of which the returned
16979 service is an instance.
16981 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16985 (simple-service 'my-mcron-job mcron-service-type
16986 #~(job '(next-hour (3)) "guix gc -F 2G"))
16990 At the core of the service abstraction lies the @code{fold-services}
16991 procedure, which is responsible for ``compiling'' a list of services
16992 down to a single directory that contains everything needed to boot and
16993 run the system---the directory shown by the @command{guix system build}
16994 command (@pxref{Invoking guix system}). In essence, it propagates
16995 service extensions down the service graph, updating each node parameters
16996 on the way, until it reaches the root node.
16998 @deffn {Scheme Procedure} fold-services @var{services} @
16999 [#:target-type @var{system-service-type}]
17000 Fold @var{services} by propagating their extensions down to the root of
17001 type @var{target-type}; return the root service adjusted accordingly.
17004 Lastly, the @code{(gnu services)} module also defines several essential
17005 service types, some of which are listed below.
17007 @defvr {Scheme Variable} system-service-type
17008 This is the root of the service graph. It produces the system directory
17009 as returned by the @command{guix system build} command.
17012 @defvr {Scheme Variable} boot-service-type
17013 The type of the ``boot service'', which produces the @dfn{boot script}.
17014 The boot script is what the initial RAM disk runs when booting.
17017 @defvr {Scheme Variable} etc-service-type
17018 The type of the @file{/etc} service. This service can be extended by
17019 passing it name/file tuples such as:
17022 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
17025 In this example, the effect would be to add an @file{/etc/issue} file
17026 pointing to the given file.
17029 @defvr {Scheme Variable} setuid-program-service-type
17030 Type for the ``setuid-program service''. This service collects lists of
17031 executable file names, passed as gexps, and adds them to the set of
17032 setuid-root programs on the system (@pxref{Setuid Programs}).
17035 @defvr {Scheme Variable} profile-service-type
17036 Type of the service that populates the @dfn{system profile}---i.e., the
17037 programs under @file{/run/current-system/profile}. Other services can
17038 extend it by passing it lists of packages to add to the system profile.
17042 @node Shepherd Services
17043 @subsubsection Shepherd Services
17045 @cindex shepherd services
17047 @cindex init system
17048 The @code{(gnu services shepherd)} module provides a way to define
17049 services managed by the GNU@tie{}Shepherd, which is the GuixSD
17050 initialization system---the first process that is started when the
17051 system boots, also known as PID@tie{}1
17052 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
17054 Services in the Shepherd can depend on each other. For instance, the
17055 SSH daemon may need to be started after the syslog daemon has been
17056 started, which in turn can only happen once all the file systems have
17057 been mounted. The simple operating system defined earlier (@pxref{Using
17058 the Configuration System}) results in a service graph like this:
17060 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
17062 You can actually generate such a graph for any operating system
17063 definition using the @command{guix system shepherd-graph} command
17064 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
17066 The @var{%shepherd-root-service} is a service object representing
17067 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
17068 by passing it lists of @code{<shepherd-service>} objects.
17070 @deftp {Data Type} shepherd-service
17071 The data type representing a service managed by the Shepherd.
17074 @item @code{provision}
17075 This is a list of symbols denoting what the service provides.
17077 These are the names that may be passed to @command{herd start},
17078 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
17079 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
17080 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
17082 @item @code{requirements} (default: @code{'()})
17083 List of symbols denoting the Shepherd services this one depends on.
17085 @item @code{respawn?} (default: @code{#t})
17086 Whether to restart the service when it stops, for instance when the
17087 underlying process dies.
17090 @itemx @code{stop} (default: @code{#~(const #f)})
17091 The @code{start} and @code{stop} fields refer to the Shepherd's
17092 facilities to start and stop processes (@pxref{Service De- and
17093 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
17094 G-expressions that get expanded in the Shepherd configuration file
17095 (@pxref{G-Expressions}).
17097 @item @code{documentation}
17098 A documentation string, as shown when running:
17101 herd doc @var{service-name}
17104 where @var{service-name} is one of the symbols in @var{provision}
17105 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
17107 @item @code{modules} (default: @var{%default-modules})
17108 This is the list of modules that must be in scope when @code{start} and
17109 @code{stop} are evaluated.
17114 @defvr {Scheme Variable} shepherd-root-service-type
17115 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
17117 This is the service type that extensions target when they want to create
17118 shepherd services (@pxref{Service Types and Services}, for an example).
17119 Each extension must pass a list of @code{<shepherd-service>}.
17122 @defvr {Scheme Variable} %shepherd-root-service
17123 This service represents PID@tie{}1.
17127 @node Documentation
17128 @section Documentation
17130 @cindex documentation, searching for
17131 @cindex searching for documentation
17132 @cindex Info, documentation format
17134 @cindex manual pages
17135 In most cases packages installed with Guix come with documentation.
17136 There are two main documentation formats: ``Info'', a browseable
17137 hypertext format used for GNU software, and ``manual pages'' (or ``man
17138 pages''), the linear documentation format traditionally found on Unix.
17139 Info manuals are accessed with the @command{info} command or with Emacs,
17140 and man pages are accessed using @command{man}.
17142 You can look for documentation of software installed on your system by
17143 keyword. For example, the following command searches for information
17144 about ``TLS'' in Info manuals:
17148 "(emacs)Network Security" -- STARTTLS
17149 "(emacs)Network Security" -- TLS
17150 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
17151 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
17156 The command below searches for the same keyword in man pages:
17160 SSL (7) - OpenSSL SSL/TLS library
17161 certtool (1) - GnuTLS certificate tool
17165 These searches are purely local to your computer so you have the
17166 guarantee that documentation you find corresponds to what you have
17167 actually installed, you can access it off-line, and your privacy is
17170 Once you have these results, you can view the relevant documentation by
17174 $ info "(gnutls)Core TLS API"
17184 Info manuals contain sections and indices as well as hyperlinks like
17185 those found in Web pages. The @command{info} reader (@pxref{Top, Info
17186 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
17187 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
17188 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
17189 Introduction}, for an introduction to Info navigation.
17191 @node Installing Debugging Files
17192 @section Installing Debugging Files
17194 @cindex debugging files
17195 Program binaries, as produced by the GCC compilers for instance, are
17196 typically written in the ELF format, with a section containing
17197 @dfn{debugging information}. Debugging information is what allows the
17198 debugger, GDB, to map binary code to source code; it is required to
17199 debug a compiled program in good conditions.
17201 The problem with debugging information is that is takes up a fair amount
17202 of disk space. For example, debugging information for the GNU C Library
17203 weighs in at more than 60 MiB. Thus, as a user, keeping all the
17204 debugging info of all the installed programs is usually not an option.
17205 Yet, space savings should not come at the cost of an impediment to
17206 debugging---especially in the GNU system, which should make it easier
17207 for users to exert their computing freedom (@pxref{GNU Distribution}).
17209 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
17210 mechanism that allows users to get the best of both worlds: debugging
17211 information can be stripped from the binaries and stored in separate
17212 files. GDB is then able to load debugging information from those files,
17213 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
17216 The GNU distribution takes advantage of this by storing debugging
17217 information in the @code{lib/debug} sub-directory of a separate package
17218 output unimaginatively called @code{debug} (@pxref{Packages with
17219 Multiple Outputs}). Users can choose to install the @code{debug} output
17220 of a package when they need it. For instance, the following command
17221 installs the debugging information for the GNU C Library and for GNU
17225 guix package -i glibc:debug guile:debug
17228 GDB must then be told to look for debug files in the user's profile, by
17229 setting the @code{debug-file-directory} variable (consider setting it
17230 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
17234 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
17237 From there on, GDB will pick up debugging information from the
17238 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
17240 In addition, you will most likely want GDB to be able to show the source
17241 code being debugged. To do that, you will have to unpack the source
17242 code of the package of interest (obtained with @code{guix build
17243 --source}, @pxref{Invoking guix build}), and to point GDB to that source
17244 directory using the @code{directory} command (@pxref{Source Path,
17245 @code{directory},, gdb, Debugging with GDB}).
17247 @c XXX: keep me up-to-date
17248 The @code{debug} output mechanism in Guix is implemented by the
17249 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
17250 opt-in---debugging information is available only for the packages
17251 with definitions explicitly declaring a @code{debug} output. This may be
17252 changed to opt-out in the future if our build farm servers can handle
17253 the load. To check whether a package has a @code{debug} output, use
17254 @command{guix package --list-available} (@pxref{Invoking guix package}).
17257 @node Security Updates
17258 @section Security Updates
17260 @cindex security updates
17261 @cindex security vulnerabilities
17262 Occasionally, important security vulnerabilities are discovered in software
17263 packages and must be patched. Guix developers try hard to keep track of
17264 known vulnerabilities and to apply fixes as soon as possible in the
17265 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
17266 containing only security updates.) The @command{guix lint} tool helps
17267 developers find out about vulnerable versions of software packages in the
17272 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
17273 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
17274 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
17278 @xref{Invoking guix lint}, for more information.
17281 As of version @value{VERSION}, the feature described below is considered
17285 Guix follows a functional
17286 package management discipline (@pxref{Introduction}), which implies
17287 that, when a package is changed, @emph{every package that depends on it}
17288 must be rebuilt. This can significantly slow down the deployment of
17289 fixes in core packages such as libc or Bash, since basically the whole
17290 distribution would need to be rebuilt. Using pre-built binaries helps
17291 (@pxref{Substitutes}), but deployment may still take more time than
17295 To address this, Guix implements @dfn{grafts}, a mechanism that allows
17296 for fast deployment of critical updates without the costs associated
17297 with a whole-distribution rebuild. The idea is to rebuild only the
17298 package that needs to be patched, and then to ``graft'' it onto packages
17299 explicitly installed by the user and that were previously referring to
17300 the original package. The cost of grafting is typically very low, and
17301 order of magnitudes lower than a full rebuild of the dependency chain.
17303 @cindex replacements of packages, for grafts
17304 For instance, suppose a security update needs to be applied to Bash.
17305 Guix developers will provide a package definition for the ``fixed''
17306 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
17307 Packages}). Then, the original package definition is augmented with a
17308 @code{replacement} field pointing to the package containing the bug fix:
17315 (replacement bash-fixed)))
17318 From there on, any package depending directly or indirectly on Bash---as
17319 reported by @command{guix gc --requisites} (@pxref{Invoking guix
17320 gc})---that is installed is automatically ``rewritten'' to refer to
17321 @var{bash-fixed} instead of @var{bash}. This grafting process takes
17322 time proportional to the size of the package, usually less than a
17323 minute for an ``average'' package on a recent machine. Grafting is
17324 recursive: when an indirect dependency requires grafting, then grafting
17325 ``propagates'' up to the package that the user is installing.
17327 Currently, the length of the name and version of the graft and that of
17328 the package it replaces (@var{bash-fixed} and @var{bash} in the example
17329 above) must be equal. This restriction mostly comes from the fact that
17330 grafting works by patching files, including binary files, directly.
17331 Other restrictions may apply: for instance, when adding a graft to a
17332 package providing a shared library, the original shared library and its
17333 replacement must have the same @code{SONAME} and be binary-compatible.
17335 The @option{--no-grafts} command-line option allows you to forcefully
17336 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
17340 guix build bash --no-grafts
17344 returns the store file name of the original Bash, whereas:
17351 returns the store file name of the ``fixed'', replacement Bash. This
17352 allows you to distinguish between the two variants of Bash.
17354 To verify which Bash your whole profile refers to, you can run
17355 (@pxref{Invoking guix gc}):
17358 guix gc -R `readlink -f ~/.guix-profile` | grep bash
17362 @dots{} and compare the store file names that you get with those above.
17363 Likewise for a complete GuixSD system generation:
17366 guix gc -R `guix system build my-config.scm` | grep bash
17369 Lastly, to check which Bash running processes are using, you can use the
17370 @command{lsof} command:
17373 lsof | grep /gnu/store/.*bash
17377 @node Package Modules
17378 @section Package Modules
17380 From a programming viewpoint, the package definitions of the
17381 GNU distribution are provided by Guile modules in the @code{(gnu packages
17382 @dots{})} name space@footnote{Note that packages under the @code{(gnu
17383 packages @dots{})} module name space are not necessarily ``GNU
17384 packages''. This module naming scheme follows the usual Guile module
17385 naming convention: @code{gnu} means that these modules are distributed
17386 as part of the GNU system, and @code{packages} identifies modules that
17387 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
17388 Reference Manual}). For instance, the @code{(gnu packages emacs)}
17389 module exports a variable named @code{emacs}, which is bound to a
17390 @code{<package>} object (@pxref{Defining Packages}).
17392 The @code{(gnu packages @dots{})} module name space is
17393 automatically scanned for packages by the command-line tools. For
17394 instance, when running @code{guix package -i emacs}, all the @code{(gnu
17395 packages @dots{})} modules are scanned until one that exports a package
17396 object whose name is @code{emacs} is found. This package search
17397 facility is implemented in the @code{(gnu packages)} module.
17399 @cindex customization, of packages
17400 @cindex package module search path
17401 Users can store package definitions in modules with different
17402 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
17403 name and module name must match. For instance, the @code{(my-packages
17404 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
17405 relative to the load path specified with @option{--load-path} or
17406 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
17407 guile, GNU Guile Reference Manual}, for details.}. These package definitions
17408 will not be visible by default. Users can invoke commands such as
17409 @command{guix package} and @command{guix build} with the
17410 @code{-e} option so that they know where to find the package. Better
17411 yet, they can use the
17412 @code{-L} option of these commands to make those modules visible
17413 (@pxref{Invoking guix build, @code{--load-path}}), or define the
17414 @code{GUIX_PACKAGE_PATH} environment variable. This environment
17415 variable makes it easy to extend or customize the distribution and is
17416 honored by all the user interfaces.
17418 @defvr {Environment Variable} GUIX_PACKAGE_PATH
17419 This is a colon-separated list of directories to search for additional
17420 package modules. Directories listed in this variable take precedence
17421 over the own modules of the distribution.
17424 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
17425 each package is built based solely on other packages in the
17426 distribution. The root of this dependency graph is a small set of
17427 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
17428 bootstrap)} module. For more information on bootstrapping,
17429 @pxref{Bootstrapping}.
17431 @node Packaging Guidelines
17432 @section Packaging Guidelines
17434 @cindex packages, creating
17435 The GNU distribution is nascent and may well lack some of your favorite
17436 packages. This section describes how you can help make the distribution
17437 grow. @xref{Contributing}, for additional information on how you can
17440 Free software packages are usually distributed in the form of
17441 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
17442 all the source files. Adding a package to the distribution means
17443 essentially two things: adding a @dfn{recipe} that describes how to
17444 build the package, including a list of other packages required to build
17445 it, and adding @dfn{package metadata} along with that recipe, such as a
17446 description and licensing information.
17448 In Guix all this information is embodied in @dfn{package definitions}.
17449 Package definitions provide a high-level view of the package. They are
17450 written using the syntax of the Scheme programming language; in fact,
17451 for each package we define a variable bound to the package definition,
17452 and export that variable from a module (@pxref{Package Modules}).
17453 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
17454 creating packages. For more information on package definitions,
17455 @pxref{Defining Packages}.
17457 Once a package definition is in place, stored in a file in the Guix
17458 source tree, it can be tested using the @command{guix build} command
17459 (@pxref{Invoking guix build}). For example, assuming the new package is
17460 called @code{gnew}, you may run this command from the Guix build tree
17461 (@pxref{Running Guix Before It Is Installed}):
17464 ./pre-inst-env guix build gnew --keep-failed
17467 Using @code{--keep-failed} makes it easier to debug build failures since
17468 it provides access to the failed build tree. Another useful
17469 command-line option when debugging is @code{--log-file}, to access the
17472 If the package is unknown to the @command{guix} command, it may be that
17473 the source file contains a syntax error, or lacks a @code{define-public}
17474 clause to export the package variable. To figure it out, you may load
17475 the module from Guile to get more information about the actual error:
17478 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
17481 Once your package builds correctly, please send us a patch
17482 (@pxref{Contributing}). Well, if you need help, we will be happy to
17483 help you too. Once the patch is committed in the Guix repository, the
17484 new package automatically gets built on the supported platforms by
17485 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
17488 @cindex substituter
17489 Users can obtain the new package definition simply by running
17490 @command{guix pull} (@pxref{Invoking guix pull}). When
17491 @code{hydra.gnu.org} is done building the package, installing the
17492 package automatically downloads binaries from there
17493 (@pxref{Substitutes}). The only place where human intervention is
17494 needed is to review and apply the patch.
17498 * Software Freedom:: What may go into the distribution.
17499 * Package Naming:: What's in a name?
17500 * Version Numbers:: When the name is not enough.
17501 * Synopses and Descriptions:: Helping users find the right package.
17502 * Python Modules:: A touch of British comedy.
17503 * Perl Modules:: Little pearls.
17504 * Java Packages:: Coffee break.
17505 * Fonts:: Fond of fonts.
17508 @node Software Freedom
17509 @subsection Software Freedom
17511 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
17512 @cindex free software
17513 The GNU operating system has been developed so that users can have
17514 freedom in their computing. GNU is @dfn{free software}, meaning that
17515 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
17516 essential freedoms}: to run the program, to study and change the program
17517 in source code form, to redistribute exact copies, and to distribute
17518 modified versions. Packages found in the GNU distribution provide only
17519 software that conveys these four freedoms.
17521 In addition, the GNU distribution follow the
17522 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
17523 software distribution guidelines}. Among other things, these guidelines
17524 reject non-free firmware, recommendations of non-free software, and
17525 discuss ways to deal with trademarks and patents.
17527 Some otherwise free upstream package sources contain a small and optional
17528 subset that violates the above guidelines, for instance because this subset
17529 is itself non-free code. When that happens, the offending items are removed
17530 with appropriate patches or code snippets in the @code{origin} form of the
17531 package (@pxref{Defining Packages}). This way, @code{guix
17532 build --source} returns the ``freed'' source rather than the unmodified
17536 @node Package Naming
17537 @subsection Package Naming
17539 @cindex package name
17540 A package has actually two names associated with it:
17541 First, there is the name of the @emph{Scheme variable}, the one following
17542 @code{define-public}. By this name, the package can be made known in the
17543 Scheme code, for instance as input to another package. Second, there is
17544 the string in the @code{name} field of a package definition. This name
17545 is used by package management commands such as
17546 @command{guix package} and @command{guix build}.
17548 Both are usually the same and correspond to the lowercase conversion of
17549 the project name chosen upstream, with underscores replaced with
17550 hyphens. For instance, GNUnet is available as @code{gnunet}, and
17551 SDL_net as @code{sdl-net}.
17553 We do not add @code{lib} prefixes for library packages, unless these are
17554 already part of the official project name. But @pxref{Python
17555 Modules} and @ref{Perl Modules} for special rules concerning modules for
17556 the Python and Perl languages.
17558 Font package names are handled differently, @pxref{Fonts}.
17561 @node Version Numbers
17562 @subsection Version Numbers
17564 @cindex package version
17565 We usually package only the latest version of a given free software
17566 project. But sometimes, for instance for incompatible library versions,
17567 two (or more) versions of the same package are needed. These require
17568 different Scheme variable names. We use the name as defined
17569 in @ref{Package Naming}
17570 for the most recent version; previous versions use the same name, suffixed
17571 by @code{-} and the smallest prefix of the version number that may
17572 distinguish the two versions.
17574 The name inside the package definition is the same for all versions of a
17575 package and does not contain any version number.
17577 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
17580 (define-public gtk+
17585 (define-public gtk+-2
17588 (version "2.24.20")
17591 If we also wanted GTK+ 3.8.2, this would be packaged as
17593 (define-public gtk+-3.8
17600 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
17601 @c for a discussion of what follows.
17602 @cindex version number, for VCS snapshots
17603 Occasionally, we package snapshots of upstream's version control system
17604 (VCS) instead of formal releases. This should remain exceptional,
17605 because it is up to upstream developers to clarify what the stable
17606 release is. Yet, it is sometimes necessary. So, what should we put in
17607 the @code{version} field?
17609 Clearly, we need to make the commit identifier of the VCS snapshot
17610 visible in the version string, but we also need to make sure that the
17611 version string is monotonically increasing so that @command{guix package
17612 --upgrade} can determine which version is newer. Since commit
17613 identifiers, notably with Git, are not monotonically increasing, we add
17614 a revision number that we increase each time we upgrade to a newer
17615 snapshot. The resulting version string looks like this:
17620 | | `-- upstream commit ID
17622 | `--- Guix package revision
17624 latest upstream version
17627 It is a good idea to strip commit identifiers in the @code{version}
17628 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
17629 aesthetics have a role to play here) as well as problems related to OS
17630 limits such as the maximum shebang length (127 bytes for the Linux
17631 kernel.) It is best to use the full commit identifiers in
17632 @code{origin}s, though, to avoid ambiguities. A typical package
17633 definition may look like this:
17637 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
17638 (revision "1")) ;Guix package revision
17640 (version (string-append "0.9-" revision "."
17641 (string-take commit 7)))
17644 (uri (git-reference
17645 (url "git://example.org/my-package.git")
17647 (sha256 (base32 "1mbikn@dots{}"))
17648 (file-name (string-append "my-package-" version
17654 @node Synopses and Descriptions
17655 @subsection Synopses and Descriptions
17657 @cindex package description
17658 @cindex package synopsis
17659 As we have seen before, each package in GNU@tie{}Guix includes a
17660 synopsis and a description (@pxref{Defining Packages}). Synopses and
17661 descriptions are important: They are what @command{guix package
17662 --search} searches, and a crucial piece of information to help users
17663 determine whether a given package suits their needs. Consequently,
17664 packagers should pay attention to what goes into them.
17666 Synopses must start with a capital letter and must not end with a
17667 period. They must not start with ``a'' or ``the'', which usually does
17668 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
17669 tool that frobs files''. The synopsis should say what the package
17670 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
17671 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
17672 matching a pattern''.
17674 Keep in mind that the synopsis must be meaningful for a very wide
17675 audience. For example, ``Manipulate alignments in the SAM format''
17676 might make sense for a seasoned bioinformatics researcher, but might be
17677 fairly unhelpful or even misleading to a non-specialized audience. It
17678 is a good idea to come up with a synopsis that gives an idea of the
17679 application domain of the package. In this example, this might give
17680 something like ``Manipulate nucleotide sequence alignments'', which
17681 hopefully gives the user a better idea of whether this is what they are
17684 Descriptions should take between five and ten lines. Use full
17685 sentences, and avoid using acronyms without first introducing them.
17686 Please avoid marketing phrases such as ``world-leading'',
17687 ``industrial-strength'', and ``next-generation'', and avoid superlatives
17688 like ``the most advanced''---they are not helpful to users looking for a
17689 package and may even sound suspicious. Instead, try to be factual,
17690 mentioning use cases and features.
17692 @cindex Texinfo markup, in package descriptions
17693 Descriptions can include Texinfo markup, which is useful to introduce
17694 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
17695 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
17696 should be careful when using some characters for example @samp{@@} and
17697 curly braces which are the basic special characters in Texinfo
17698 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
17699 such as @command{guix package --show} take care of rendering it
17702 Synopses and descriptions are translated by volunteers
17703 @uref{http://translationproject.org/domain/guix-packages.html, at the
17704 Translation Project} so that as many users as possible can read them in
17705 their native language. User interfaces search them and display them in
17706 the language specified by the current locale.
17708 Translation is a lot of work so, as a packager, please pay even more
17709 attention to your synopses and descriptions as every change may entail
17710 additional work for translators. In order to help them, it is possible
17711 to make recommendations or instructions visible to them by inserting
17712 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
17716 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
17717 (description "ARandR is designed to provide a simple visual front end
17718 for the X11 resize-and-rotate (RandR) extension. @dots{}")
17722 @node Python Modules
17723 @subsection Python Modules
17726 We currently package Python 2 and Python 3, under the Scheme variable names
17727 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
17728 To avoid confusion and naming clashes with other programming languages, it
17729 seems desirable that the name of a package for a Python module contains
17730 the word @code{python}.
17732 Some modules are compatible with only one version of Python, others with both.
17733 If the package Foo compiles only with Python 3, we name it
17734 @code{python-foo}; if it compiles only with Python 2, we name it
17735 @code{python2-foo}. If it is compatible with both versions, we create two
17736 packages with the corresponding names.
17738 If a project already contains the word @code{python}, we drop this;
17739 for instance, the module python-dateutil is packaged under the names
17740 @code{python-dateutil} and @code{python2-dateutil}. If the project name
17741 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
17744 @subsubsection Specifying Dependencies
17745 @cindex inputs, for Python packages
17747 Dependency information for Python packages is usually available in the
17748 package source tree, with varying degrees of accuracy: in the
17749 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
17751 Your mission, when writing a recipe for a Python package, is to map
17752 these dependencies to the appropriate type of ``input'' (@pxref{package
17753 Reference, inputs}). Although the @code{pypi} importer normally does a
17754 good job (@pxref{Invoking guix import}), you may want to check the
17755 following check list to determine which dependency goes where.
17760 We currently package Python 2 with @code{setuptools} and @code{pip}
17761 installed like Python 3.4 has per default. Thus you don't need to
17762 specify either of these as an input. @command{guix lint} will warn you
17766 Python dependencies required at run time go into
17767 @code{propagated-inputs}. They are typically defined with the
17768 @code{install_requires} keyword in @file{setup.py}, or in the
17769 @file{requirements.txt} file.
17772 Python packages required only at build time---e.g., those listed with
17773 the @code{setup_requires} keyword in @file{setup.py}---or only for
17774 testing---e.g., those in @code{tests_require}---go into
17775 @code{native-inputs}. The rationale is that (1) they do not need to be
17776 propagated because they are not needed at run time, and (2) in a
17777 cross-compilation context, it's the ``native'' input that we'd want.
17779 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
17780 frameworks. Of course if any of these packages is also required at
17781 run-time, it needs to go to @code{propagated-inputs}.
17784 Anything that does not fall in the previous categories goes to
17785 @code{inputs}, for example programs or C libraries required for building
17786 Python packages containing C extensions.
17789 If a Python package has optional dependencies (@code{extras_require}),
17790 it is up to you to decide whether to add them or not, based on their
17791 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
17798 @subsection Perl Modules
17801 Perl programs standing for themselves are named as any other package,
17802 using the lowercase upstream name.
17803 For Perl packages containing a single class, we use the lowercase class name,
17804 replace all occurrences of @code{::} by dashes and prepend the prefix
17806 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
17807 Modules containing several classes keep their lowercase upstream name and
17808 are also prepended by @code{perl-}. Such modules tend to have the word
17809 @code{perl} somewhere in their name, which gets dropped in favor of the
17810 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
17813 @node Java Packages
17814 @subsection Java Packages
17817 Java programs standing for themselves are named as any other package,
17818 using the lowercase upstream name.
17820 To avoid confusion and naming clashes with other programming languages,
17821 it is desirable that the name of a package for a Java package is
17822 prefixed with @code{java-}. If a project already contains the word
17823 @code{java}, we drop this; for instance, the package @code{ngsjava} is
17824 packaged under the name @code{java-ngs}.
17826 For Java packages containing a single class or a small class hierarchy,
17827 we use the lowercase class name, replace all occurrences of @code{.} by
17828 dashes and prepend the prefix @code{java-}. So the class
17829 @code{apache.commons.cli} becomes package
17830 @code{java-apache-commons-cli}.
17837 For fonts that are in general not installed by a user for typesetting
17838 purposes, or that are distributed as part of a larger software package,
17839 we rely on the general packaging rules for software; for instance, this
17840 applies to the fonts delivered as part of the X.Org system or fonts that
17841 are part of TeX Live.
17843 To make it easier for a user to search for fonts, names for other packages
17844 containing only fonts are constructed as follows, independently of the
17845 upstream package name.
17847 The name of a package containing only one font family starts with
17848 @code{font-}; it is followed by the foundry name and a dash @code{-}
17849 if the foundry is known, and the font family name, in which spaces are
17850 replaced by dashes (and as usual, all upper case letters are transformed
17852 For example, the Gentium font family by SIL is packaged under the name
17853 @code{font-sil-gentium}.
17855 For a package containing several font families, the name of the collection
17856 is used in the place of the font family name.
17857 For instance, the Liberation fonts consist of three families,
17858 Liberation Sans, Liberation Serif and Liberation Mono.
17859 These could be packaged separately under the names
17860 @code{font-liberation-sans} and so on; but as they are distributed together
17861 under a common name, we prefer to package them together as
17862 @code{font-liberation}.
17864 In the case where several formats of the same font family or font collection
17865 are packaged separately, a short form of the format, prepended by a dash,
17866 is added to the package name. We use @code{-ttf} for TrueType fonts,
17867 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
17872 @node Bootstrapping
17873 @section Bootstrapping
17875 @c Adapted from the ELS 2013 paper.
17877 @cindex bootstrapping
17879 Bootstrapping in our context refers to how the distribution gets built
17880 ``from nothing''. Remember that the build environment of a derivation
17881 contains nothing but its declared inputs (@pxref{Introduction}). So
17882 there's an obvious chicken-and-egg problem: how does the first package
17883 get built? How does the first compiler get compiled? Note that this is
17884 a question of interest only to the curious hacker, not to the regular
17885 user, so you can shamelessly skip this section if you consider yourself
17886 a ``regular user''.
17888 @cindex bootstrap binaries
17889 The GNU system is primarily made of C code, with libc at its core. The
17890 GNU build system itself assumes the availability of a Bourne shell and
17891 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
17892 `grep'. Furthermore, build programs---programs that run
17893 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
17894 (@pxref{Derivations}). Consequently, to be able to build anything at
17895 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
17896 Binutils, libc, and the other packages mentioned above---the
17897 @dfn{bootstrap binaries}.
17899 These bootstrap binaries are ``taken for granted'', though we can also
17900 re-create them if needed (more on that later).
17902 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
17904 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
17905 @c large image, it's hard to scroll. Oh well.
17906 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17908 The figure above shows the very beginning of the dependency graph of the
17909 distribution, corresponding to the package definitions of the @code{(gnu
17910 packages bootstrap)} module. A similar figure can be generated with
17911 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17914 guix graph -t derivation \
17915 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17919 At this level of detail, things are
17920 slightly complex. First, Guile itself consists of an ELF executable,
17921 along with many source and compiled Scheme files that are dynamically
17922 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17923 tarball shown in this graph. This tarball is part of Guix's ``source''
17924 distribution, and gets inserted into the store with @code{add-to-store}
17925 (@pxref{The Store}).
17927 But how do we write a derivation that unpacks this tarball and adds it
17928 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17929 derivation---the first one that gets built---uses @code{bash} as its
17930 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17931 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17932 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17933 the Guix source distribution, whose sole purpose is to allow the Guile
17934 tarball to be unpacked.
17936 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17937 Guile that can be used to run subsequent build programs. Its first task
17938 is to download tarballs containing the other pre-built binaries---this
17939 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17940 @code{ftp-client.scm} are used for this purpose. The
17941 @code{module-import.drv} derivations import those modules in a directory
17942 in the store, using the original layout. The
17943 @code{module-import-compiled.drv} derivations compile those modules, and
17944 write them in an output directory with the right layout. This
17945 corresponds to the @code{#:modules} argument of
17946 @code{build-expression->derivation} (@pxref{Derivations}).
17948 Finally, the various tarballs are unpacked by the
17949 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17950 etc., at which point we have a working C tool chain.
17953 @unnumberedsubsec Building the Build Tools
17955 Bootstrapping is complete when we have a full tool chain that does not
17956 depend on the pre-built bootstrap tools discussed above. This
17957 no-dependency requirement is verified by checking whether the files of
17958 the final tool chain contain references to the @file{/gnu/store}
17959 directories of the bootstrap inputs. The process that leads to this
17960 ``final'' tool chain is described by the package definitions found in
17961 the @code{(gnu packages commencement)} module.
17963 The @command{guix graph} command allows us to ``zoom out'' compared to
17964 the graph above, by looking at the level of package objects instead of
17965 individual derivations---remember that a package may translate to
17966 several derivations, typically one derivation to download its source,
17967 one to build the Guile modules it needs, and one to actually build the
17968 package from source. The command:
17971 guix graph -t bag \
17972 -e '(@@@@ (gnu packages commencement)
17973 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17977 produces the dependency graph leading to the ``final'' C
17978 library@footnote{You may notice the @code{glibc-intermediate} label,
17979 suggesting that it is not @emph{quite} final, but as a good
17980 approximation, we will consider it final.}, depicted below.
17982 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17984 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17985 The first tool that gets built with the bootstrap binaries is
17986 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17987 for all the following packages. From there Findutils and Diffutils get
17990 Then come the first-stage Binutils and GCC, built as pseudo cross
17991 tools---i.e., with @code{--target} equal to @code{--host}. They are
17992 used to build libc. Thanks to this cross-build trick, this libc is
17993 guaranteed not to hold any reference to the initial tool chain.
17995 From there the final Binutils and GCC (not shown above) are built.
17997 from the final Binutils, and links programs against the just-built libc.
17998 This tool chain is used to build the other packages used by Guix and by
17999 the GNU Build System: Guile, Bash, Coreutils, etc.
18001 And voilà! At this point we have the complete set of build tools that
18002 the GNU Build System expects. These are in the @code{%final-inputs}
18003 variable of the @code{(gnu packages commencement)} module, and are
18004 implicitly used by any package that uses @code{gnu-build-system}
18005 (@pxref{Build Systems, @code{gnu-build-system}}).
18008 @unnumberedsubsec Building the Bootstrap Binaries
18010 @cindex bootstrap binaries
18011 Because the final tool chain does not depend on the bootstrap binaries,
18012 those rarely need to be updated. Nevertheless, it is useful to have an
18013 automated way to produce them, should an update occur, and this is what
18014 the @code{(gnu packages make-bootstrap)} module provides.
18016 The following command builds the tarballs containing the bootstrap
18017 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
18018 of Coreutils and other basic command-line tools):
18021 guix build bootstrap-tarballs
18024 The generated tarballs are those that should be referred to in the
18025 @code{(gnu packages bootstrap)} module mentioned at the beginning of
18028 Still here? Then perhaps by now you've started to wonder: when do we
18029 reach a fixed point? That is an interesting question! The answer is
18030 unknown, but if you would like to investigate further (and have
18031 significant computational and storage resources to do so), then let us
18035 @section Porting to a New Platform
18037 As discussed above, the GNU distribution is self-contained, and
18038 self-containment is achieved by relying on pre-built ``bootstrap
18039 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
18040 operating system kernel, CPU architecture, and application binary
18041 interface (ABI). Thus, to port the distribution to a platform that is
18042 not yet supported, one must build those bootstrap binaries, and update
18043 the @code{(gnu packages bootstrap)} module to use them on that platform.
18045 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
18046 When everything goes well, and assuming the GNU tool chain supports the
18047 target platform, this can be as simple as running a command like this
18051 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
18054 For this to work, the @code{glibc-dynamic-linker} procedure in
18055 @code{(gnu packages bootstrap)} must be augmented to return the right
18056 file name for libc's dynamic linker on that platform; likewise,
18057 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
18058 taught about the new platform.
18060 Once these are built, the @code{(gnu packages bootstrap)} module needs
18061 to be updated to refer to these binaries on the target platform. That
18062 is, the hashes and URLs of the bootstrap tarballs for the new platform
18063 must be added alongside those of the currently supported platforms. The
18064 bootstrap Guile tarball is treated specially: it is expected to be
18065 available locally, and @file{gnu/local.mk} has rules do download it for
18066 the supported architectures; a rule for the new platform must be added
18069 In practice, there may be some complications. First, it may be that the
18070 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
18071 above) is not recognized by all the GNU tools. Typically, glibc
18072 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
18073 configure flag (see @code{gcc.scm} for examples of how to handle this).
18074 Second, some of the required packages could fail to build for that
18075 platform. Lastly, the generated binaries could be broken for some
18078 @c *********************************************************************
18079 @include contributing.texi
18081 @c *********************************************************************
18082 @node Acknowledgments
18083 @chapter Acknowledgments
18085 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
18086 which was designed and
18087 implemented by Eelco Dolstra, with contributions from other people (see
18088 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
18089 management, and promoted unprecedented features, such as transactional
18090 package upgrades and rollbacks, per-user profiles, and referentially
18091 transparent build processes. Without this work, Guix would not exist.
18093 The Nix-based software distributions, Nixpkgs and NixOS, have also been
18094 an inspiration for Guix.
18096 GNU@tie{}Guix itself is a collective work with contributions from a
18097 number of people. See the @file{AUTHORS} file in Guix for more
18098 information on these fine people. The @file{THANKS} file lists people
18099 who have helped by reporting bugs, taking care of the infrastructure,
18100 providing artwork and themes, making suggestions, and more---thank you!
18103 @c *********************************************************************
18104 @node GNU Free Documentation License
18105 @appendix GNU Free Documentation License
18106 @cindex license, GNU Free Documentation License
18107 @include fdl-1.3.texi
18109 @c *********************************************************************
18110 @node Concept Index
18111 @unnumbered Concept Index
18114 @node Programming Index
18115 @unnumbered Programming Index
18116 @syncodeindex tp fn
18117 @syncodeindex vr fn
18122 @c Local Variables:
18123 @c ispell-local-dictionary: "american";