6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
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13 @set OPENPGP-SIGNING-KEY-ID BCA689B636553801C3C62150197A5888235FACAC
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 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
41 Permission is granted to copy, distribute and/or modify this document
42 under the terms of the GNU Free Documentation License, Version 1.3 or
43 any later version published by the Free Software Foundation; with no
44 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
45 copy of the license is included in the section entitled ``GNU Free
46 Documentation License''.
49 @dircategory System administration
51 * Guix: (guix). Manage installed software and system configuration.
52 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
53 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
54 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
55 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
58 @dircategory Software development
60 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
61 * guix build: (guix)Invoking guix build. Building packages.
62 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
66 @title GNU Guix Reference Manual
67 @subtitle Using the GNU Guix Functional Package Manager
68 @author The GNU Guix Developers
71 @vskip 0pt plus 1filll
72 Edition @value{EDITION} @*
80 @c *********************************************************************
84 This document describes GNU Guix version @value{VERSION}, a functional
85 package management tool written for the GNU system.
88 * Introduction:: What is Guix about?
89 * Installation:: Installing Guix.
90 * Package Management:: Package installation, upgrade, etc.
91 * Programming Interface:: Using Guix in Scheme.
92 * Utilities:: Package management commands.
93 * GNU Distribution:: Software for your friendly GNU system.
94 * Contributing:: Your help needed!
96 * Acknowledgments:: Thanks!
97 * GNU Free Documentation License:: The license of this manual.
98 * Concept Index:: Concepts.
99 * Programming Index:: Data types, functions, and variables.
102 --- The Detailed Node Listing ---
106 * Binary Installation:: Getting Guix running in no time!
107 * Requirements:: Software needed to build and run Guix.
108 * Running the Test Suite:: Testing Guix.
109 * Setting Up the Daemon:: Preparing the build daemon's environment.
110 * Invoking guix-daemon:: Running the build daemon.
111 * Application Setup:: Application-specific setup.
113 Setting Up the Daemon
115 * Build Environment Setup:: Preparing the isolated build environment.
116 * Daemon Offload Setup:: Offloading builds to remote machines.
120 * Features:: How Guix will make your life brighter.
121 * Invoking guix package:: Package installation, removal, etc.
122 * Substitutes:: Downloading pre-built binaries.
123 * Packages with Multiple Outputs:: Single source package, multiple outputs.
124 * Invoking guix gc:: Running the garbage collector.
125 * Invoking guix pull:: Fetching the latest Guix and distribution.
126 * Invoking guix pack:: Creating software bundles.
127 * Invoking guix archive:: Exporting and importing store files.
129 Programming Interface
131 * Defining Packages:: Defining new packages.
132 * Build Systems:: Specifying how packages are built.
133 * The Store:: Manipulating the package store.
134 * Derivations:: Low-level interface to package derivations.
135 * The Store Monad:: Purely functional interface to the store.
136 * G-Expressions:: Manipulating build expressions.
140 * package Reference:: The package data type.
141 * origin Reference:: The origin data type.
145 * Invoking guix build:: Building packages from the command line.
146 * Invoking guix edit:: Editing package definitions.
147 * Invoking guix download:: Downloading a file and printing its hash.
148 * Invoking guix hash:: Computing the cryptographic hash of a file.
149 * Invoking guix import:: Importing package definitions.
150 * Invoking guix refresh:: Updating package definitions.
151 * Invoking guix lint:: Finding errors in package definitions.
152 * Invoking guix size:: Profiling disk usage.
153 * Invoking guix graph:: Visualizing the graph of packages.
154 * Invoking guix environment:: Setting up development environments.
155 * Invoking guix publish:: Sharing substitutes.
156 * Invoking guix challenge:: Challenging substitute servers.
157 * Invoking guix copy:: Copying to and from a remote store.
158 * Invoking guix container:: Process isolation.
160 Invoking @command{guix build}
162 * Common Build Options:: Build options for most commands.
163 * Package Transformation Options:: Creating variants of packages.
164 * Additional Build Options:: Options specific to 'guix build'.
168 * System Installation:: Installing the whole operating system.
169 * System Configuration:: Configuring the operating system.
170 * Documentation:: Browsing software user manuals.
171 * Installing Debugging Files:: Feeding the debugger.
172 * Security Updates:: Deploying security fixes quickly.
173 * Package Modules:: Packages from the programmer's viewpoint.
174 * Packaging Guidelines:: Growing the distribution.
175 * Bootstrapping:: GNU/Linux built from scratch.
176 * Porting:: Targeting another platform or kernel.
180 * Limitations:: What you can expect.
181 * Hardware Considerations:: Supported hardware.
182 * USB Stick Installation:: Preparing the installation medium.
183 * Preparing for Installation:: Networking, partitioning, etc.
184 * Proceeding with the Installation:: The real thing.
185 * Installing GuixSD in a VM:: GuixSD playground.
186 * Building the Installation Image:: How this comes to be.
190 * Using the Configuration System:: Customizing your GNU system.
191 * operating-system Reference:: Detail of operating-system declarations.
192 * File Systems:: Configuring file system mounts.
193 * Mapped Devices:: Block device extra processing.
194 * User Accounts:: Specifying user accounts.
195 * Locales:: Language and cultural convention settings.
196 * Services:: Specifying system services.
197 * Setuid Programs:: Programs running with root privileges.
198 * X.509 Certificates:: Authenticating HTTPS servers.
199 * Name Service Switch:: Configuring libc's name service switch.
200 * Initial RAM Disk:: Linux-Libre bootstrapping.
201 * GRUB Configuration:: Configuring the boot loader.
202 * Invoking guix system:: Instantiating a system configuration.
203 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
204 * Defining Services:: Adding new service definitions.
208 * Base Services:: Essential system services.
209 * Scheduled Job Execution:: The mcron service.
210 * Log Rotation:: The rottlog service.
211 * Networking Services:: Network setup, SSH daemon, etc.
212 * X Window:: Graphical display.
213 * Printing Services:: Local and remote printer support.
214 * Desktop Services:: D-Bus and desktop services.
215 * Database Services:: SQL databases.
216 * Mail Services:: IMAP, POP3, SMTP, and all that.
217 * Messaging Services:: Messaging services.
218 * Kerberos Services:: Kerberos services.
219 * Web Services:: Web servers.
220 * VPN Services:: VPN daemons.
221 * Network File System:: NFS related services.
222 * Continuous Integration:: The Cuirass service.
223 * Power management Services:: The TLP tool.
224 * Miscellaneous Services:: Other services.
228 * Service Composition:: The model for composing services.
229 * Service Types and Services:: Types and services.
230 * Service Reference:: API reference.
231 * Shepherd Services:: A particular type of service.
235 * Software Freedom:: What may go into the distribution.
236 * Package Naming:: What's in a name?
237 * Version Numbers:: When the name is not enough.
238 * Synopses and Descriptions:: Helping users find the right package.
239 * Python Modules:: A touch of British comedy.
240 * Perl Modules:: Little pearls.
241 * Java Packages:: Coffee break.
242 * Fonts:: Fond of fonts.
246 * Building from Git:: The latest and greatest.
247 * Running Guix Before It Is Installed:: Hacker tricks.
248 * The Perfect Setup:: The right tools.
249 * Coding Style:: Hygiene of the contributor.
250 * Submitting Patches:: Share your work.
254 * Programming Paradigm:: How to compose your elements.
255 * Modules:: Where to store your code?
256 * Data Types and Pattern Matching:: Implementing data structures.
257 * Formatting Code:: Writing conventions.
262 @c *********************************************************************
264 @chapter Introduction
267 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
268 using the international phonetic alphabet (IPA).} is a package
269 management tool for the GNU system. Guix makes it easy for unprivileged
270 users to install, upgrade, or remove packages, to roll back to a
271 previous package set, to build packages from source, and generally
272 assists with the creation and maintenance of software environments.
274 @cindex user interfaces
275 Guix provides a command-line package management interface
276 (@pxref{Invoking guix package}), a set of command-line utilities
277 (@pxref{Utilities}), as well as Scheme programming interfaces
278 (@pxref{Programming Interface}).
280 Its @dfn{build daemon} is responsible for building packages on behalf of
281 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
282 binaries from authorized sources (@pxref{Substitutes}).
284 @cindex extensibility of the distribution
285 @cindex customization, of packages
286 Guix includes package definitions for many GNU and non-GNU packages, all
287 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
288 user's computing freedom}. It is @emph{extensible}: users can write
289 their own package definitions (@pxref{Defining Packages}) and make them
290 available as independent package modules (@pxref{Package Modules}). It
291 is also @emph{customizable}: users can @emph{derive} specialized package
292 definitions from existing ones, including from the command line
293 (@pxref{Package Transformation Options}).
295 @cindex Guix System Distribution
297 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
298 where it complements the available tools without interference
299 (@pxref{Installation}), or you can use it as part of the standalone
300 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
301 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
302 system configuration and Guix takes care of instantiating the
303 configuration in a transactional, reproducible, and stateless fashion
304 (@pxref{System Configuration}).
306 @cindex functional package management
307 Under the hood, Guix implements the @dfn{functional package management}
308 discipline pioneered by Nix (@pxref{Acknowledgments}).
309 In Guix, the package build and installation process is seen
310 as a @emph{function}, in the mathematical sense. That function takes inputs,
311 such as build scripts, a compiler, and libraries, and
312 returns an installed package. As a pure function, its result depends
313 solely on its inputs---for instance, it cannot refer to software or
314 scripts that were not explicitly passed as inputs. A build function
315 always produces the same result when passed a given set of inputs. It
316 cannot alter the environment of the running system in
317 any way; for instance, it cannot create, modify, or delete files outside
318 of its build and installation directories. This is achieved by running
319 build processes in isolated environments (or @dfn{containers}), where only their
320 explicit inputs are visible.
323 The result of package build functions is @dfn{cached} in the file
324 system, in a special directory called @dfn{the store} (@pxref{The
325 Store}). Each package is installed in a directory of its own in the
326 store---by default under @file{/gnu/store}. The directory name contains
327 a hash of all the inputs used to build that package; thus, changing an
328 input yields a different directory name.
330 This approach is the foundation for the salient features of Guix: support
331 for transactional package upgrade and rollback, per-user installation, and
332 garbage collection of packages (@pxref{Features}).
335 @c *********************************************************************
337 @chapter Installation
339 @cindex installing Guix
340 GNU Guix is available for download from its website at
341 @url{http://www.gnu.org/software/guix/}. This section describes the
342 software requirements of Guix, as well as how to install it and get
345 Note that this section is concerned with the installation of the package
346 manager, which can be done on top of a running GNU/Linux system. If,
347 instead, you want to install the complete GNU operating system,
348 @pxref{System Installation}.
350 @cindex foreign distro
351 When installed on a running GNU/Linux system---thereafter called a
352 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
353 without interference. Its data lives exclusively in two directories,
354 usually @file{/gnu/store} and @file{/var/guix}; other files on your
355 system, such as @file{/etc}, are left untouched.
357 Once installed, Guix can be updated by running @command{guix pull}
358 (@pxref{Invoking guix pull}).
361 * Binary Installation:: Getting Guix running in no time!
362 * Requirements:: Software needed to build and run Guix.
363 * Running the Test Suite:: Testing Guix.
364 * Setting Up the Daemon:: Preparing the build daemon's environment.
365 * Invoking guix-daemon:: Running the build daemon.
366 * Application Setup:: Application-specific setup.
369 @node Binary Installation
370 @section Binary Installation
372 @cindex installing Guix from binaries
373 This section describes how to install Guix on an arbitrary system from a
374 self-contained tarball providing binaries for Guix and for all its
375 dependencies. This is often quicker than installing from source, which
376 is described in the next sections. The only requirement is to have
379 Installing goes along these lines:
383 @cindex downloading Guix binary
384 Download the binary tarball from
385 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
386 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
387 already running the kernel Linux, and so on.
389 @c The following is somewhat duplicated in ``System Installation''.
390 Make sure to download the associated @file{.sig} file and to verify the
391 authenticity of the tarball against it, along these lines:
394 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
395 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
398 If that command fails because you do not have the required public key,
399 then run this command to import it:
402 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
406 and rerun the @code{gpg --verify} command.
407 @c end authentication part
414 # tar --warning=no-timestamp -xf \
415 guix-binary-@value{VERSION}.@var{system}.tar.xz
416 # mv var/guix /var/ && mv gnu /
419 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
420 The latter contains a ready-to-use profile for @code{root} (see next
423 Do @emph{not} unpack the tarball on a working Guix system since that
424 would overwrite its own essential files.
426 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
427 not emit warnings about ``implausibly old time stamps'' (such
428 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
430 They stem from the fact that all the
431 files in the archive have their modification time set to zero (which
432 means January 1st, 1970.) This is done on purpose to make sure the
433 archive content is independent of its creation time, thus making it
437 Make @code{root}'s profile available under @file{~/.guix-profile}:
440 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
444 Source @file{etc/profile} to augment @code{PATH} and other relevant
445 environment variables:
448 # GUIX_PROFILE=$HOME/.guix-profile \
449 source $GUIX_PROFILE/etc/profile
453 Create the group and user accounts for build users as explained below
454 (@pxref{Build Environment Setup}).
457 Run the daemon, and set it to automatically start on boot.
459 If your host distro uses the systemd init system, this can be achieved
462 @c Versions of systemd that supported symlinked service files are not
463 @c yet widely deployed, so we should suggest that users copy the service
466 @c See this thread for more information:
467 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
470 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
472 # systemctl start guix-daemon && systemctl enable guix-daemon
475 If your host distro uses the Upstart init system:
478 # initctl reload-configuration
479 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
483 Otherwise, you can still start the daemon manually with:
486 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
490 Make the @command{guix} command available to other users on the machine,
494 # mkdir -p /usr/local/bin
496 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
499 It is also a good idea to make the Info version of this manual available
503 # mkdir -p /usr/local/share/info
504 # cd /usr/local/share/info
505 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
509 That way, assuming @file{/usr/local/share/info} is in the search path,
510 running @command{info guix} will open this manual (@pxref{Other Info
511 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
515 @cindex substitutes, authorization thereof
516 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
517 (@pxref{Substitutes}), authorize them:
520 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
524 Each user may need to perform a few additional steps to make their Guix
525 environment ready for use, @pxref{Application Setup}.
528 Voilà, the installation is complete!
530 You can confirm that Guix is working by installing a sample package into
534 # guix package -i hello
537 The @code{guix} package must remain available in @code{root}'s profile,
538 or it would become subject to garbage collection---in which case you
539 would find yourself badly handicapped by the lack of the @command{guix}
540 command. In other words, do not remove @code{guix} by running
541 @code{guix package -r guix}.
543 The binary installation tarball can be (re)produced and verified simply
544 by running the following command in the Guix source tree:
547 make guix-binary.@var{system}.tar.xz
551 ... which, in turn, runs:
554 guix pack -s @var{system} --localstatedir guix
557 @xref{Invoking guix pack}, for more info on this handy tool.
560 @section Requirements
562 This section lists requirements when building Guix from source. The
563 build procedure for Guix is the same as for other GNU software, and is
564 not covered here. Please see the files @file{README} and @file{INSTALL}
565 in the Guix source tree for additional details.
567 GNU Guix depends on the following packages:
570 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
571 later, including 2.2.x;
572 @item @url{http://gnupg.org/, GNU libgcrypt};
574 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
575 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
576 Guile,, gnutls-guile, GnuTLS-Guile});
577 @item @url{http://www.gnu.org/software/make/, GNU Make}.
580 The following dependencies are optional:
585 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
586 allow you to use the @command{guix import pypi} command (@pxref{Invoking
587 guix import}). It is of
588 interest primarily for developers and not for casual users.
591 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
592 Support for build offloading (@pxref{Daemon Offload Setup}) and
593 @command{guix copy} (@pxref{Invoking guix copy}) depends on
594 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
595 version 0.10.2 or later.
598 When @url{http://zlib.net, zlib} is available, @command{guix publish}
599 can compress build byproducts (@pxref{Invoking guix publish}).
602 Unless @code{--disable-daemon} was passed to @command{configure}, the
603 following packages are also needed:
606 @item @url{http://sqlite.org, SQLite 3};
607 @item @url{http://www.bzip.org, libbz2};
608 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
612 @cindex state directory
613 When configuring Guix on a system that already has a Guix installation,
614 be sure to specify the same state directory as the existing installation
615 using the @code{--localstatedir} option of the @command{configure}
616 script (@pxref{Directory Variables, @code{localstatedir},, standards,
617 GNU Coding Standards}). The @command{configure} script protects against
618 unintended misconfiguration of @var{localstatedir} so you do not
619 inadvertently corrupt your store (@pxref{The Store}).
621 @cindex Nix, compatibility
622 When a working installation of @url{http://nixos.org/nix/, the Nix package
623 manager} is available, you
624 can instead configure Guix with @code{--disable-daemon}. In that case,
625 Nix replaces the three dependencies above.
627 Guix is compatible with Nix, so it is possible to share the same store
628 between both. To do so, you must pass @command{configure} not only the
629 same @code{--with-store-dir} value, but also the same
630 @code{--localstatedir} value. The latter is essential because it
631 specifies where the database that stores metadata about the store is
632 located, among other things. The default values for Nix are
633 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
634 Note that @code{--disable-daemon} is not required if
635 your goal is to share the store with Nix.
637 @node Running the Test Suite
638 @section Running the Test Suite
641 After a successful @command{configure} and @code{make} run, it is a good
642 idea to run the test suite. It can help catch issues with the setup or
643 environment, or bugs in Guix itself---and really, reporting test
644 failures is a good way to help improve the software. To run the test
651 Test cases can run in parallel: you can use the @code{-j} option of
652 GNU@tie{}make to speed things up. The first run may take a few minutes
653 on a recent machine; subsequent runs will be faster because the store
654 that is created for test purposes will already have various things in
657 It is also possible to run a subset of the tests by defining the
658 @code{TESTS} makefile variable as in this example:
661 make check TESTS="tests/store.scm tests/cpio.scm"
664 By default, tests results are displayed at a file level. In order to
665 see the details of every individual test cases, it is possible to define
666 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
669 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
672 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
673 @file{test-suite.log} file. Please specify the Guix version being used
674 as well as version numbers of the dependencies (@pxref{Requirements}) in
677 Guix also comes with a whole-system test suite that tests complete
678 GuixSD operating system instances. It can only run on systems where
679 Guix is already installed, using:
686 or, again, by defining @code{TESTS} to select a subset of tests to run:
689 make check-system TESTS="basic mcron"
692 These system tests are defined in the @code{(gnu tests @dots{})}
693 modules. They work by running the operating systems under test with
694 lightweight instrumentation in a virtual machine (VM). They can be
695 computationally intensive or rather cheap, depending on whether
696 substitutes are available for their dependencies (@pxref{Substitutes}).
697 Some of them require a lot of storage space to hold VM images.
699 Again in case of test failures, please send @email{bug-guix@@gnu.org}
702 @node Setting Up the Daemon
703 @section Setting Up the Daemon
706 Operations such as building a package or running the garbage collector
707 are all performed by a specialized process, the @dfn{build daemon}, on
708 behalf of clients. Only the daemon may access the store and its
709 associated database. Thus, any operation that manipulates the store
710 goes through the daemon. For instance, command-line tools such as
711 @command{guix package} and @command{guix build} communicate with the
712 daemon (@i{via} remote procedure calls) to instruct it what to do.
714 The following sections explain how to prepare the build daemon's
715 environment. See also @ref{Substitutes}, for information on how to allow
716 the daemon to download pre-built binaries.
719 * Build Environment Setup:: Preparing the isolated build environment.
720 * Daemon Offload Setup:: Offloading builds to remote machines.
723 @node Build Environment Setup
724 @subsection Build Environment Setup
726 @cindex build environment
727 In a standard multi-user setup, Guix and its daemon---the
728 @command{guix-daemon} program---are installed by the system
729 administrator; @file{/gnu/store} is owned by @code{root} and
730 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
731 Guix tools to build packages or otherwise access the store, and the
732 daemon will do it on their behalf, ensuring that the store is kept in a
733 consistent state, and allowing built packages to be shared among users.
736 When @command{guix-daemon} runs as @code{root}, you may not want package
737 build processes themselves to run as @code{root} too, for obvious
738 security reasons. To avoid that, a special pool of @dfn{build users}
739 should be created for use by build processes started by the daemon.
740 These build users need not have a shell and a home directory: they will
741 just be used when the daemon drops @code{root} privileges in build
742 processes. Having several such users allows the daemon to launch
743 distinct build processes under separate UIDs, which guarantees that they
744 do not interfere with each other---an essential feature since builds are
745 regarded as pure functions (@pxref{Introduction}).
747 On a GNU/Linux system, a build user pool may be created like this (using
748 Bash syntax and the @code{shadow} commands):
750 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
751 @c for why `-G' is needed.
753 # groupadd --system guixbuild
754 # for i in `seq -w 1 10`;
756 useradd -g guixbuild -G guixbuild \
757 -d /var/empty -s `which nologin` \
758 -c "Guix build user $i" --system \
764 The number of build users determines how many build jobs may run in
765 parallel, as specified by the @option{--max-jobs} option
766 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
767 @command{guix system vm} and related commands, you may need to add the
768 build users to the @code{kvm} group so they can access @file{/dev/kvm},
769 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
770 (@pxref{Invoking guix system}).
772 The @code{guix-daemon} program may then be run as @code{root} with the
773 following command@footnote{If your machine uses the systemd init system,
774 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
775 file in @file{/etc/systemd/system} will ensure that
776 @command{guix-daemon} is automatically started. Similarly, if your
777 machine uses the Upstart init system, drop the
778 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
779 file in @file{/etc/init}.}:
782 # guix-daemon --build-users-group=guixbuild
787 This way, the daemon starts build processes in a chroot, under one of
788 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
789 environment contains nothing but:
791 @c Keep this list in sync with libstore/build.cc! -----------------------
794 a minimal @code{/dev} directory, created mostly independently from the
795 host @code{/dev}@footnote{``Mostly'', because while the set of files
796 that appear in the chroot's @code{/dev} is fixed, most of these files
797 can only be created if the host has them.};
800 the @code{/proc} directory; it only shows the processes of the container
801 since a separate PID name space is used;
804 @file{/etc/passwd} with an entry for the current user and an entry for
808 @file{/etc/group} with an entry for the user's group;
811 @file{/etc/hosts} with an entry that maps @code{localhost} to
815 a writable @file{/tmp} directory.
818 You can influence the directory where the daemon stores build trees
819 @i{via} the @code{TMPDIR} environment variable. However, the build tree
820 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
821 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
822 This way, the value of @code{TMPDIR} does not leak inside build
823 environments, which avoids discrepancies in cases where build processes
824 capture the name of their build tree.
827 The daemon also honors the @code{http_proxy} environment variable for
828 HTTP downloads it performs, be it for fixed-output derivations
829 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
831 If you are installing Guix as an unprivileged user, it is still possible
832 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
833 However, build processes will not be isolated from one another, and not
834 from the rest of the system. Thus, build processes may interfere with
835 each other, and may access programs, libraries, and other files
836 available on the system---making it much harder to view them as
837 @emph{pure} functions.
840 @node Daemon Offload Setup
841 @subsection Using the Offload Facility
845 When desired, the build daemon can @dfn{offload} derivation builds to
846 other machines running Guix, using the @code{offload} @dfn{build
847 hook}@footnote{This feature is available only when
848 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
850 feature is enabled, a list of user-specified build machines is read from
851 @file{/etc/guix/machines.scm}; every time a build is requested, for
852 instance via @code{guix build}, the daemon attempts to offload it to one
853 of the machines that satisfy the constraints of the derivation, in
854 particular its system type---e.g., @file{x86_64-linux}. Missing
855 prerequisites for the build are copied over SSH to the target machine,
856 which then proceeds with the build; upon success the output(s) of the
857 build are copied back to the initial machine.
859 The @file{/etc/guix/machines.scm} file typically looks like this:
863 (name "eightysix.example.org")
864 (system "x86_64-linux")
865 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
867 (speed 2.)) ;incredibly fast!
870 (name "meeps.example.org")
871 (system "mips64el-linux")
872 (host-key "ssh-rsa AAAAB3Nza@dots{}")
875 (string-append (getenv "HOME")
876 "/.ssh/identity-for-guix"))))
880 In the example above we specify a list of two build machines, one for
881 the @code{x86_64} architecture and one for the @code{mips64el}
884 In fact, this file is---not surprisingly!---a Scheme file that is
885 evaluated when the @code{offload} hook is started. Its return value
886 must be a list of @code{build-machine} objects. While this example
887 shows a fixed list of build machines, one could imagine, say, using
888 DNS-SD to return a list of potential build machines discovered in the
889 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
890 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
893 @deftp {Data Type} build-machine
894 This data type represents build machines to which the daemon may offload
895 builds. The important fields are:
900 The host name of the remote machine.
903 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
906 The user account to use when connecting to the remote machine over SSH.
907 Note that the SSH key pair must @emph{not} be passphrase-protected, to
908 allow non-interactive logins.
911 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
912 This is used to authenticate the machine when we connect to it. It is a
913 long string that looks like this:
916 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
919 If the machine is running the OpenSSH daemon, @command{sshd}, the host
920 key can be found in a file such as
921 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
923 If the machine is running the SSH daemon of GNU@tie{}lsh,
924 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
925 similar file. It can be converted to the OpenSSH format using
926 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
929 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
930 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
935 A number of optional fields may be specified:
939 @item @code{port} (default: @code{22})
940 Port number of SSH server on the machine.
942 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
943 The SSH private key file to use when connecting to the machine, in
946 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
947 @itemx @code{compression-level} (default: @code{3})
948 The SSH-level compression methods and compression level requested.
950 Note that offloading relies on SSH compression to reduce bandwidth usage
951 when transferring files to and from build machines.
953 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
954 File name of the Unix-domain socket @command{guix-daemon} is listening
957 @item @code{parallel-builds} (default: @code{1})
958 The number of builds that may run in parallel on the machine.
960 @item @code{speed} (default: @code{1.0})
961 A ``relative speed factor''. The offload scheduler will tend to prefer
962 machines with a higher speed factor.
964 @item @code{features} (default: @code{'()})
965 A list of strings denoting specific features supported by the machine.
966 An example is @code{"kvm"} for machines that have the KVM Linux modules
967 and corresponding hardware support. Derivations can request features by
968 name, and they will be scheduled on matching build machines.
973 The @code{guile} command must be in the search path on the build
974 machines. In addition, the Guix modules must be in
975 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
976 this is the case by running:
979 ssh build-machine guile -c "'(use-modules (guix config))'"
982 There is one last thing to do once @file{machines.scm} is in place. As
983 explained above, when offloading, files are transferred back and forth
984 between the machine stores. For this to work, you first need to
985 generate a key pair on each machine to allow the daemon to export signed
986 archives of files from the store (@pxref{Invoking guix archive}):
989 # guix archive --generate-key
993 Each build machine must authorize the key of the master machine so that
994 it accepts store items it receives from the master:
997 # guix archive --authorize < master-public-key.txt
1001 Likewise, the master machine must authorize the key of each build machine.
1003 All the fuss with keys is here to express pairwise mutual trust
1004 relations between the master and the build machines. Concretely, when
1005 the master receives files from a build machine (and @i{vice versa}), its
1006 build daemon can make sure they are genuine, have not been tampered
1007 with, and that they are signed by an authorized key.
1009 @cindex offload test
1010 To test whether your setup is operational, run this command on the
1017 This will attempt to connect to each of the build machines specified in
1018 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1019 available on each machine, attempt to export to the machine and import
1020 from it, and report any error in the process.
1022 If you want to test a different machine file, just specify it on the
1026 # guix offload test machines-qualif.scm
1029 Last, you can test the subset of the machines whose name matches a
1030 regular expression like this:
1033 # guix offload test machines.scm '\.gnu\.org$'
1036 @node Invoking guix-daemon
1037 @section Invoking @command{guix-daemon}
1039 The @command{guix-daemon} program implements all the functionality to
1040 access the store. This includes launching build processes, running the
1041 garbage collector, querying the availability of a build result, etc. It
1042 is normally run as @code{root} like this:
1045 # guix-daemon --build-users-group=guixbuild
1049 For details on how to set it up, @pxref{Setting Up the Daemon}.
1052 @cindex container, build environment
1053 @cindex build environment
1054 @cindex reproducible builds
1055 By default, @command{guix-daemon} launches build processes under
1056 different UIDs, taken from the build group specified with
1057 @code{--build-users-group}. In addition, each build process is run in a
1058 chroot environment that only contains the subset of the store that the
1059 build process depends on, as specified by its derivation
1060 (@pxref{Programming Interface, derivation}), plus a set of specific
1061 system directories. By default, the latter contains @file{/dev} and
1062 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1063 @dfn{container}: in addition to having its own file system tree, it has
1064 a separate mount name space, its own PID name space, network name space,
1065 etc. This helps achieve reproducible builds (@pxref{Features}).
1067 When the daemon performs a build on behalf of the user, it creates a
1068 build directory under @file{/tmp} or under the directory specified by
1069 its @code{TMPDIR} environment variable; this directory is shared with
1070 the container for the duration of the build. Be aware that using a
1071 directory other than @file{/tmp} can affect build results---for example,
1072 with a longer directory name, a build process that uses Unix-domain
1073 sockets might hit the name length limitation for @code{sun_path}, which
1074 it would otherwise not hit.
1076 The build directory is automatically deleted upon completion, unless the
1077 build failed and the client specified @option{--keep-failed}
1078 (@pxref{Invoking guix build, @option{--keep-failed}}).
1080 The following command-line options are supported:
1083 @item --build-users-group=@var{group}
1084 Take users from @var{group} to run build processes (@pxref{Setting Up
1085 the Daemon, build users}).
1087 @item --no-substitutes
1089 Do not use substitutes for build products. That is, always build things
1090 locally instead of allowing downloads of pre-built binaries
1091 (@pxref{Substitutes}).
1093 By default substitutes are used, unless the client---such as the
1094 @command{guix package} command---is explicitly invoked with
1095 @code{--no-substitutes}.
1097 When the daemon runs with @code{--no-substitutes}, clients can still
1098 explicitly enable substitution @i{via} the @code{set-build-options}
1099 remote procedure call (@pxref{The Store}).
1101 @item --substitute-urls=@var{urls}
1102 @anchor{daemon-substitute-urls}
1103 Consider @var{urls} the default whitespace-separated list of substitute
1104 source URLs. When this option is omitted,
1105 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1106 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1108 This means that substitutes may be downloaded from @var{urls}, as long
1109 as they are signed by a trusted signature (@pxref{Substitutes}).
1112 @item --no-build-hook
1113 Do not use the @dfn{build hook}.
1115 The build hook is a helper program that the daemon can start and to
1116 which it submits build requests. This mechanism is used to offload
1117 builds to other machines (@pxref{Daemon Offload Setup}).
1119 @item --cache-failures
1120 Cache build failures. By default, only successful builds are cached.
1122 When this option is used, @command{guix gc --list-failures} can be used
1123 to query the set of store items marked as failed; @command{guix gc
1124 --clear-failures} removes store items from the set of cached failures.
1125 @xref{Invoking guix gc}.
1127 @item --cores=@var{n}
1129 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1132 The default value is @code{0}, but it may be overridden by clients, such
1133 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1136 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1137 in the build process, which can then use it to exploit internal
1138 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1140 @item --max-jobs=@var{n}
1142 Allow at most @var{n} build jobs in parallel. The default value is
1143 @code{1}. Setting it to @code{0} means that no builds will be performed
1144 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1145 Setup}), or simply fail.
1147 @item --rounds=@var{N}
1148 Build each derivation @var{n} times in a row, and raise an error if
1149 consecutive build results are not bit-for-bit identical. Note that this
1150 setting can be overridden by clients such as @command{guix build}
1151 (@pxref{Invoking guix build}).
1153 When used in conjunction with @option{--keep-failed}, the differing
1154 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1155 This makes it easy to look for differences between the two results.
1158 Produce debugging output.
1160 This is useful to debug daemon start-up issues, but then it may be
1161 overridden by clients, for example the @code{--verbosity} option of
1162 @command{guix build} (@pxref{Invoking guix build}).
1164 @item --chroot-directory=@var{dir}
1165 Add @var{dir} to the build chroot.
1167 Doing this may change the result of build processes---for instance if
1168 they use optional dependencies found in @var{dir} when it is available,
1169 and not otherwise. For that reason, it is not recommended to do so.
1170 Instead, make sure that each derivation declares all the inputs that it
1173 @item --disable-chroot
1174 Disable chroot builds.
1176 Using this option is not recommended since, again, it would allow build
1177 processes to gain access to undeclared dependencies. It is necessary,
1178 though, when @command{guix-daemon} is running under an unprivileged user
1181 @item --disable-log-compression
1182 Disable compression of the build logs.
1184 Unless @code{--lose-logs} is used, all the build logs are kept in the
1185 @var{localstatedir}. To save space, the daemon automatically compresses
1186 them with bzip2 by default. This option disables that.
1188 @item --disable-deduplication
1189 @cindex deduplication
1190 Disable automatic file ``deduplication'' in the store.
1192 By default, files added to the store are automatically ``deduplicated'':
1193 if a newly added file is identical to another one found in the store,
1194 the daemon makes the new file a hard link to the other file. This can
1195 noticeably reduce disk usage, at the expense of slightly increased
1196 input/output load at the end of a build process. This option disables
1199 @item --gc-keep-outputs[=yes|no]
1200 Tell whether the garbage collector (GC) must keep outputs of live
1203 When set to ``yes'', the GC will keep the outputs of any live derivation
1204 available in the store---the @code{.drv} files. The default is ``no'',
1205 meaning that derivation outputs are kept only if they are GC roots.
1207 @item --gc-keep-derivations[=yes|no]
1208 Tell whether the garbage collector (GC) must keep derivations
1209 corresponding to live outputs.
1211 When set to ``yes'', as is the case by default, the GC keeps
1212 derivations---i.e., @code{.drv} files---as long as at least one of their
1213 outputs is live. This allows users to keep track of the origins of
1214 items in their store. Setting it to ``no'' saves a bit of disk space.
1216 Note that when both @code{--gc-keep-derivations} and
1217 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1218 prerequisites (the sources, compiler, libraries, and other build-time
1219 tools) of live objects in the store, regardless of whether these
1220 prerequisites are live. This is convenient for developers since it
1221 saves rebuilds or downloads.
1223 @item --impersonate-linux-2.6
1224 On Linux-based systems, impersonate Linux 2.6. This means that the
1225 kernel's @code{uname} system call will report 2.6 as the release number.
1227 This might be helpful to build programs that (usually wrongfully) depend
1228 on the kernel version number.
1231 Do not keep build logs. By default they are kept under
1232 @code{@var{localstatedir}/guix/log}.
1234 @item --system=@var{system}
1235 Assume @var{system} as the current system type. By default it is the
1236 architecture/kernel pair found at configure time, such as
1237 @code{x86_64-linux}.
1239 @item --listen=@var{socket}
1240 Listen for connections on @var{socket}, the file name of a Unix-domain
1241 socket. The default socket is
1242 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1243 useful in exceptional circumstances, such as if you need to run several
1244 daemons on the same machine.
1248 @node Application Setup
1249 @section Application Setup
1251 @cindex foreign distro
1252 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1253 so-called @dfn{foreign distro}---a few additional steps are needed to
1254 get everything in place. Here are some of them.
1258 @anchor{locales-and-locpath}
1259 @cindex locales, when not on GuixSD
1261 @vindex GUIX_LOCPATH
1262 Packages installed @i{via} Guix will not use the locale data of the
1263 host system. Instead, you must first install one of the locale packages
1264 available with Guix and then define the @code{GUIX_LOCPATH} environment
1268 $ guix package -i glibc-locales
1269 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1272 Note that the @code{glibc-locales} package contains data for all the
1273 locales supported by the GNU@tie{}libc and weighs in at around
1274 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1275 limited to a few UTF-8 locales.
1277 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1278 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1279 Manual}). There are two important differences though:
1283 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1284 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1285 to make sure the programs of the foreign distro will not end up loading
1286 incompatible locale data.
1289 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1290 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1291 should your Guix profile contain a mixture of programs linked against
1292 different libc version, each libc version will only try to load locale
1293 data in the right format.
1296 This is important because the locale data format used by different libc
1297 versions may be incompatible.
1299 @subsection Name Service Switch
1301 @cindex name service switch, glibc
1302 @cindex NSS (name service switch), glibc
1303 @cindex nscd (name service caching daemon)
1304 @cindex name service caching daemon (nscd)
1305 When using Guix on a foreign distro, we @emph{strongly recommend} that
1306 the system run the GNU C library's @dfn{name service cache daemon},
1307 @command{nscd}, which should be listening on the
1308 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1309 installed with Guix may fail to look up host names or user accounts, or
1310 may even crash. The next paragraphs explain why.
1312 @cindex @file{nsswitch.conf}
1313 The GNU C library implements a @dfn{name service switch} (NSS), which is
1314 an extensible mechanism for ``name lookups'' in general: host name
1315 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1316 The GNU C Library Reference Manual}).
1318 @cindex Network information service (NIS)
1319 @cindex NIS (Network information service)
1320 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1321 lookup implementations: for example, the @code{nss-mdns} plugin allow
1322 resolution of @code{.local} host names, the @code{nis} plugin allows
1323 user account lookup using the Network information service (NIS), and so
1324 on. These extra ``lookup services'' are configured system-wide in
1325 @file{/etc/nsswitch.conf}, and all the programs running on the system
1326 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1329 When they perform a name lookup---for instance by calling the
1330 @code{getaddrinfo} function in C---applications first try to connect to
1331 the nscd; on success, nscd performs name lookups on their behalf. If
1332 the nscd is not running, then they perform the name lookup by
1333 themselves, by loading the name lookup services into their own address
1334 space and running it. These name lookup services---the
1335 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1336 the host system's C library, rather than from the C library the
1337 application is linked against (the C library coming from Guix).
1339 And this is where the problem is: if your application is linked against
1340 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1341 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1342 likely crash or have its name lookups fail unexpectedly.
1344 Running @command{nscd} on the system, among other advantages, eliminates
1345 this binary incompatibility problem because those @code{libnss_*.so}
1346 files are loaded in the @command{nscd} process, not in applications
1349 @subsection X11 Fonts
1352 The majority of graphical applications use Fontconfig to locate and
1353 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1354 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1355 by default. Thus, to allow graphical applications installed with Guix
1356 to display fonts, you have to install fonts with Guix as well.
1357 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1358 @code{font-gnu-freefont-ttf}.
1360 To display text written in Chinese languages, Japanese, or Korean in
1361 graphical applications, consider installing
1362 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1363 has multiple outputs, one per language family (@pxref{Packages with
1364 Multiple Outputs}). For instance, the following command installs fonts
1365 for Chinese languages:
1368 guix package -i font-adobe-source-han-sans:cn
1371 @cindex @code{xterm}
1372 Older programs such as @command{xterm} do not use Fontconfig and instead
1373 rely on server-side font rendering. Such programs require to specify a
1374 full name of a font using XLFD (X Logical Font Description), like this:
1377 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1380 To be able to use such full names for the TrueType fonts installed in
1381 your Guix profile, you need to extend the font path of the X server:
1384 xset +fp ~/.guix-profile/share/fonts/truetype
1387 @cindex @code{xlsfonts}
1388 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1389 to make sure your TrueType fonts are listed there.
1391 @subsection X.509 Certificates
1393 @cindex @code{nss-certs}
1394 The @code{nss-certs} package provides X.509 certificates, which allow
1395 programs to authenticate Web servers accessed over HTTPS.
1397 When using Guix on a foreign distro, you can install this package and
1398 define the relevant environment variables so that packages know where to
1399 look for certificates. @xref{X.509 Certificates}, for detailed
1402 @subsection Emacs Packages
1404 @cindex @code{emacs}
1405 When you install Emacs packages with Guix, the elisp files may be placed
1406 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1408 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1409 directory exists because potentially there may exist thousands of Emacs
1410 packages and storing all their files in a single directory may be not
1411 reliable (because of name conflicts). So we think using a separate
1412 directory for each package is a good idea. It is very similar to how
1413 the Emacs package system organizes the file structure (@pxref{Package
1414 Files,,, emacs, The GNU Emacs Manual}).
1416 By default, Emacs (installed with Guix) ``knows'' where these packages
1417 are placed, so you do not need to perform any configuration. If, for
1418 some reason, you want to avoid auto-loading Emacs packages installed
1419 with Guix, you can do so by running Emacs with @code{--no-site-file}
1420 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1424 @c *********************************************************************
1425 @node Package Management
1426 @chapter Package Management
1429 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1430 remove software packages, without having to know about their build
1431 procedures or dependencies. Guix also goes beyond this obvious set of
1434 This chapter describes the main features of Guix, as well as the
1435 package management tools it provides. Along with the command-line
1436 interface described below (@pxref{Invoking guix package, @code{guix
1437 package}}), you may also use Emacs Interface (@pxref{Top,,,
1438 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1439 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1443 guix package -i emacs-guix
1447 * Features:: How Guix will make your life brighter.
1448 * Invoking guix package:: Package installation, removal, etc.
1449 * Substitutes:: Downloading pre-built binaries.
1450 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1451 * Invoking guix gc:: Running the garbage collector.
1452 * Invoking guix pull:: Fetching the latest Guix and distribution.
1453 * Invoking guix pack:: Creating software bundles.
1454 * Invoking guix archive:: Exporting and importing store files.
1460 When using Guix, each package ends up in the @dfn{package store}, in its
1461 own directory---something that resembles
1462 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1464 Instead of referring to these directories, users have their own
1465 @dfn{profile}, which points to the packages that they actually want to
1466 use. These profiles are stored within each user's home directory, at
1467 @code{$HOME/.guix-profile}.
1469 For example, @code{alice} installs GCC 4.7.2. As a result,
1470 @file{/home/alice/.guix-profile/bin/gcc} points to
1471 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1472 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1473 simply continues to point to
1474 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1475 coexist on the same system without any interference.
1477 The @command{guix package} command is the central tool to manage
1478 packages (@pxref{Invoking guix package}). It operates on the per-user
1479 profiles, and can be used @emph{with normal user privileges}.
1481 @cindex transactions
1482 The command provides the obvious install, remove, and upgrade
1483 operations. Each invocation is actually a @emph{transaction}: either
1484 the specified operation succeeds, or nothing happens. Thus, if the
1485 @command{guix package} process is terminated during the transaction,
1486 or if a power outage occurs during the transaction, then the user's
1487 profile remains in its previous state, and remains usable.
1489 In addition, any package transaction may be @emph{rolled back}. So, if,
1490 for example, an upgrade installs a new version of a package that turns
1491 out to have a serious bug, users may roll back to the previous instance
1492 of their profile, which was known to work well. Similarly, the global
1493 system configuration on GuixSD is subject to
1494 transactional upgrades and roll-back
1495 (@pxref{Using the Configuration System}).
1497 All packages in the package store may be @emph{garbage-collected}.
1498 Guix can determine which packages are still referenced by user
1499 profiles, and remove those that are provably no longer referenced
1500 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1501 generations of their profile so that the packages they refer to can be
1504 @cindex reproducibility
1505 @cindex reproducible builds
1506 Finally, Guix takes a @dfn{purely functional} approach to package
1507 management, as described in the introduction (@pxref{Introduction}).
1508 Each @file{/gnu/store} package directory name contains a hash of all the
1509 inputs that were used to build that package---compiler, libraries, build
1510 scripts, etc. This direct correspondence allows users to make sure a
1511 given package installation matches the current state of their
1512 distribution. It also helps maximize @dfn{build reproducibility}:
1513 thanks to the isolated build environments that are used, a given build
1514 is likely to yield bit-identical files when performed on different
1515 machines (@pxref{Invoking guix-daemon, container}).
1518 This foundation allows Guix to support @dfn{transparent binary/source
1519 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1520 available from an external source---a @dfn{substitute}, Guix just
1521 downloads it and unpacks it;
1522 otherwise, it builds the package from source, locally
1523 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1524 reproducible, users do not have to trust servers that provide
1525 substitutes: they can force a local build and @emph{challenge} providers
1526 (@pxref{Invoking guix challenge}).
1528 Control over the build environment is a feature that is also useful for
1529 developers. The @command{guix environment} command allows developers of
1530 a package to quickly set up the right development environment for their
1531 package, without having to manually install the dependencies of the
1532 package into their profile (@pxref{Invoking guix environment}).
1534 @node Invoking guix package
1535 @section Invoking @command{guix package}
1537 @cindex installing packages
1538 @cindex removing packages
1539 @cindex package installation
1540 @cindex package removal
1541 The @command{guix package} command is the tool that allows users to
1542 install, upgrade, and remove packages, as well as rolling back to
1543 previous configurations. It operates only on the user's own profile,
1544 and works with normal user privileges (@pxref{Features}). Its syntax
1548 guix package @var{options}
1550 @cindex transactions
1551 Primarily, @var{options} specifies the operations to be performed during
1552 the transaction. Upon completion, a new profile is created, but
1553 previous @dfn{generations} of the profile remain available, should the user
1556 For example, to remove @code{lua} and install @code{guile} and
1557 @code{guile-cairo} in a single transaction:
1560 guix package -r lua -i guile guile-cairo
1563 @command{guix package} also supports a @dfn{declarative approach}
1564 whereby the user specifies the exact set of packages to be available and
1565 passes it @i{via} the @option{--manifest} option
1566 (@pxref{profile-manifest, @option{--manifest}}).
1569 For each user, a symlink to the user's default profile is automatically
1570 created in @file{$HOME/.guix-profile}. This symlink always points to the
1571 current generation of the user's default profile. Thus, users can add
1572 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1573 variable, and so on.
1574 @cindex search paths
1575 If you are not using the Guix System Distribution, consider adding the
1576 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1577 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1578 shells get all the right environment variable definitions:
1581 GUIX_PROFILE="$HOME/.guix-profile" \
1582 source "$HOME/.guix-profile/etc/profile"
1585 In a multi-user setup, user profiles are stored in a place registered as
1586 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1587 to (@pxref{Invoking guix gc}). That directory is normally
1588 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1589 @var{localstatedir} is the value passed to @code{configure} as
1590 @code{--localstatedir}, and @var{user} is the user name. The
1591 @file{per-user} directory is created when @command{guix-daemon} is
1592 started, and the @var{user} sub-directory is created by @command{guix
1595 The @var{options} can be among the following:
1599 @item --install=@var{package} @dots{}
1600 @itemx -i @var{package} @dots{}
1601 Install the specified @var{package}s.
1603 Each @var{package} may specify either a simple package name, such as
1604 @code{guile}, or a package name followed by an at-sign and version number,
1605 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1606 case, the newest version prefixed by @code{1.8} is selected.)
1608 If no version number is specified, the
1609 newest available version will be selected. In addition, @var{package}
1610 may contain a colon, followed by the name of one of the outputs of the
1611 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1612 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1613 name (and optionally version) are searched for among the GNU
1614 distribution modules (@pxref{Package Modules}).
1616 @cindex propagated inputs
1617 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1618 that automatically get installed along with the required package
1619 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1620 @code{package} objects}, for information about propagated inputs in
1621 package definitions).
1623 @anchor{package-cmd-propagated-inputs}
1624 An example is the GNU MPC library: its C header files refer to those of
1625 the GNU MPFR library, which in turn refer to those of the GMP library.
1626 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1627 in the profile; removing MPC also removes MPFR and GMP---unless they had
1628 also been explicitly installed by the user.
1630 Besides, packages sometimes rely on the definition of environment
1631 variables for their search paths (see explanation of
1632 @code{--search-paths} below). Any missing or possibly incorrect
1633 environment variable definitions are reported here.
1635 @item --install-from-expression=@var{exp}
1637 Install the package @var{exp} evaluates to.
1639 @var{exp} must be a Scheme expression that evaluates to a
1640 @code{<package>} object. This option is notably useful to disambiguate
1641 between same-named variants of a package, with expressions such as
1642 @code{(@@ (gnu packages base) guile-final)}.
1644 Note that this option installs the first output of the specified
1645 package, which may be insufficient when needing a specific output of a
1646 multiple-output package.
1648 @item --install-from-file=@var{file}
1649 @itemx -f @var{file}
1650 Install the package that the code within @var{file} evaluates to.
1652 As an example, @var{file} might contain a definition like this
1653 (@pxref{Defining Packages}):
1656 @verbatiminclude package-hello.scm
1659 Developers may find it useful to include such a @file{guix.scm} file
1660 in the root of their project source tree that can be used to test
1661 development snapshots and create reproducible development environments
1662 (@pxref{Invoking guix environment}).
1664 @item --remove=@var{package} @dots{}
1665 @itemx -r @var{package} @dots{}
1666 Remove the specified @var{package}s.
1668 As for @code{--install}, each @var{package} may specify a version number
1669 and/or output name in addition to the package name. For instance,
1670 @code{-r glibc:debug} would remove the @code{debug} output of
1673 @item --upgrade[=@var{regexp} @dots{}]
1674 @itemx -u [@var{regexp} @dots{}]
1675 @cindex upgrading packages
1676 Upgrade all the installed packages. If one or more @var{regexp}s are
1677 specified, upgrade only installed packages whose name matches a
1678 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1680 Note that this upgrades package to the latest version of packages found
1681 in the distribution currently installed. To update your distribution,
1682 you should regularly run @command{guix pull} (@pxref{Invoking guix
1685 @item --do-not-upgrade[=@var{regexp} @dots{}]
1686 When used together with the @code{--upgrade} option, do @emph{not}
1687 upgrade any packages whose name matches a @var{regexp}. For example, to
1688 upgrade all packages in the current profile except those containing the
1689 substring ``emacs'':
1692 $ guix package --upgrade . --do-not-upgrade emacs
1695 @item @anchor{profile-manifest}--manifest=@var{file}
1696 @itemx -m @var{file}
1697 @cindex profile declaration
1698 @cindex profile manifest
1699 Create a new generation of the profile from the manifest object
1700 returned by the Scheme code in @var{file}.
1702 This allows you to @emph{declare} the profile's contents rather than
1703 constructing it through a sequence of @code{--install} and similar
1704 commands. The advantage is that @var{file} can be put under version
1705 control, copied to different machines to reproduce the same profile, and
1708 @c FIXME: Add reference to (guix profile) documentation when available.
1709 @var{file} must return a @dfn{manifest} object, which is roughly a list
1712 @findex packages->manifest
1714 (use-package-modules guile emacs)
1719 ;; Use a specific package output.
1720 (list guile-2.0 "debug")))
1723 @findex specification->package+output
1724 In this example we have to know which modules define the @code{emacs}
1725 and @code{guile-2.0} variables to provide the right
1726 @code{use-package-modules} line, which can be cumbersome. We can
1727 instead provide regular package specifications and let
1728 @code{specification->package-output} look up the corresponding package
1733 (map (compose list specification->package+output)
1734 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1738 @cindex rolling back
1739 @cindex undoing transactions
1740 @cindex transactions, undoing
1741 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1742 the last transaction.
1744 When combined with options such as @code{--install}, roll back occurs
1745 before any other actions.
1747 When rolling back from the first generation that actually contains
1748 installed packages, the profile is made to point to the @dfn{zeroth
1749 generation}, which contains no files apart from its own metadata.
1751 After having rolled back, installing, removing, or upgrading packages
1752 overwrites previous future generations. Thus, the history of the
1753 generations in a profile is always linear.
1755 @item --switch-generation=@var{pattern}
1756 @itemx -S @var{pattern}
1758 Switch to a particular generation defined by @var{pattern}.
1760 @var{pattern} may be either a generation number or a number prefixed
1761 with ``+'' or ``-''. The latter means: move forward/backward by a
1762 specified number of generations. For example, if you want to return to
1763 the latest generation after @code{--roll-back}, use
1764 @code{--switch-generation=+1}.
1766 The difference between @code{--roll-back} and
1767 @code{--switch-generation=-1} is that @code{--switch-generation} will
1768 not make a zeroth generation, so if a specified generation does not
1769 exist, the current generation will not be changed.
1771 @item --search-paths[=@var{kind}]
1772 @cindex search paths
1773 Report environment variable definitions, in Bash syntax, that may be
1774 needed in order to use the set of installed packages. These environment
1775 variables are used to specify @dfn{search paths} for files used by some
1776 of the installed packages.
1778 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1779 environment variables to be defined so it can look for headers and
1780 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1781 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1782 library are installed in the profile, then @code{--search-paths} will
1783 suggest setting these variables to @code{@var{profile}/include} and
1784 @code{@var{profile}/lib}, respectively.
1786 The typical use case is to define these environment variables in the
1790 $ eval `guix package --search-paths`
1793 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1794 meaning that the returned environment variable definitions will either
1795 be exact settings, or prefixes or suffixes of the current value of these
1796 variables. When omitted, @var{kind} defaults to @code{exact}.
1798 This option can also be used to compute the @emph{combined} search paths
1799 of several profiles. Consider this example:
1802 $ guix package -p foo -i guile
1803 $ guix package -p bar -i guile-json
1804 $ guix package -p foo -p bar --search-paths
1807 The last command above reports about the @code{GUILE_LOAD_PATH}
1808 variable, even though, taken individually, neither @file{foo} nor
1809 @file{bar} would lead to that recommendation.
1812 @item --profile=@var{profile}
1813 @itemx -p @var{profile}
1814 Use @var{profile} instead of the user's default profile.
1817 Produce verbose output. In particular, emit the build log of the
1818 environment on the standard error port.
1821 Use the bootstrap Guile to build the profile. This option is only
1822 useful to distribution developers.
1826 In addition to these actions, @command{guix package} supports the
1827 following options to query the current state of a profile, or the
1828 availability of packages:
1832 @item --search=@var{regexp}
1833 @itemx -s @var{regexp}
1834 @cindex searching for packages
1835 List the available packages whose name, synopsis, or description matches
1836 @var{regexp}. Print all the metadata of matching packages in
1837 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1838 GNU recutils manual}).
1840 This allows specific fields to be extracted using the @command{recsel}
1841 command, for instance:
1844 $ guix package -s malloc | recsel -p name,version
1852 Similarly, to show the name of all the packages available under the
1853 terms of the GNU@tie{}LGPL version 3:
1856 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1863 It is also possible to refine search results using several @code{-s}
1864 flags. For example, the following command returns a list of board
1868 $ guix package -s '\<board\>' -s game | recsel -p name
1873 If we were to omit @code{-s game}, we would also get software packages
1874 that deal with printed circuit boards; removing the angle brackets
1875 around @code{board} would further add packages that have to do with
1878 And now for a more elaborate example. The following command searches
1879 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1880 libraries, and prints the name and synopsis of the matching packages:
1883 $ guix package -s crypto -s library | \
1884 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1888 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1889 information on @dfn{selection expressions} for @code{recsel -e}.
1891 @item --show=@var{package}
1892 Show details about @var{package}, taken from the list of available packages, in
1893 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1897 $ guix package --show=python | recsel -p name,version
1905 You may also specify the full name of a package to only get details about a
1906 specific version of it:
1908 $ guix package --show=python@@3.4 | recsel -p name,version
1915 @item --list-installed[=@var{regexp}]
1916 @itemx -I [@var{regexp}]
1917 List the currently installed packages in the specified profile, with the
1918 most recently installed packages shown last. When @var{regexp} is
1919 specified, list only installed packages whose name matches @var{regexp}.
1921 For each installed package, print the following items, separated by
1922 tabs: the package name, its version string, the part of the package that
1923 is installed (for instance, @code{out} for the default output,
1924 @code{include} for its headers, etc.), and the path of this package in
1927 @item --list-available[=@var{regexp}]
1928 @itemx -A [@var{regexp}]
1929 List packages currently available in the distribution for this system
1930 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1931 installed packages whose name matches @var{regexp}.
1933 For each package, print the following items separated by tabs: its name,
1934 its version string, the parts of the package (@pxref{Packages with
1935 Multiple Outputs}), and the source location of its definition.
1937 @item --list-generations[=@var{pattern}]
1938 @itemx -l [@var{pattern}]
1940 Return a list of generations along with their creation dates; for each
1941 generation, show the installed packages, with the most recently
1942 installed packages shown last. Note that the zeroth generation is never
1945 For each installed package, print the following items, separated by
1946 tabs: the name of a package, its version string, the part of the package
1947 that is installed (@pxref{Packages with Multiple Outputs}), and the
1948 location of this package in the store.
1950 When @var{pattern} is used, the command returns only matching
1951 generations. Valid patterns include:
1954 @item @emph{Integers and comma-separated integers}. Both patterns denote
1955 generation numbers. For instance, @code{--list-generations=1} returns
1958 And @code{--list-generations=1,8,2} outputs three generations in the
1959 specified order. Neither spaces nor trailing commas are allowed.
1961 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1962 specified generations and everything in between. Note that the start of
1963 a range must be smaller than its end.
1965 It is also possible to omit the endpoint. For example,
1966 @code{--list-generations=2..}, returns all generations starting from the
1969 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1970 or months by passing an integer along with the first letter of the
1971 duration. For example, @code{--list-generations=20d} lists generations
1972 that are up to 20 days old.
1975 @item --delete-generations[=@var{pattern}]
1976 @itemx -d [@var{pattern}]
1977 When @var{pattern} is omitted, delete all generations except the current
1980 This command accepts the same patterns as @option{--list-generations}.
1981 When @var{pattern} is specified, delete the matching generations. When
1982 @var{pattern} specifies a duration, generations @emph{older} than the
1983 specified duration match. For instance, @code{--delete-generations=1m}
1984 deletes generations that are more than one month old.
1986 If the current generation matches, it is @emph{not} deleted. Also, the
1987 zeroth generation is never deleted.
1989 Note that deleting generations prevents rolling back to them.
1990 Consequently, this command must be used with care.
1994 Finally, since @command{guix package} may actually start build
1995 processes, it supports all the common build options (@pxref{Common Build
1996 Options}). It also supports package transformation options, such as
1997 @option{--with-source} (@pxref{Package Transformation Options}).
1998 However, note that package transformations are lost when upgrading; to
1999 preserve transformations across upgrades, you should define your own
2000 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2001 (@pxref{Defining Packages}).
2005 @section Substitutes
2008 @cindex pre-built binaries
2009 Guix supports transparent source/binary deployment, which means that it
2010 can either build things locally, or download pre-built items from a
2011 server. We call these pre-built items @dfn{substitutes}---they are
2012 substitutes for local build results. In many cases, downloading a
2013 substitute is much faster than building things locally.
2015 Substitutes can be anything resulting from a derivation build
2016 (@pxref{Derivations}). Of course, in the common case, they are
2017 pre-built package binaries, but source tarballs, for instance, which
2018 also result from derivation builds, can be available as substitutes.
2020 The @code{hydra.gnu.org} server is a front-end to a build farm that
2021 builds packages from the GNU distribution continuously for some
2022 architectures, and makes them available as substitutes. This is the
2023 default source of substitutes; it can be overridden by passing the
2024 @option{--substitute-urls} option either to @command{guix-daemon}
2025 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2026 or to client tools such as @command{guix package}
2027 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2030 Substitute URLs can be either HTTP or HTTPS.
2031 HTTPS is recommended because communications are encrypted; conversely,
2032 using HTTP makes all communications visible to an eavesdropper, who
2033 could use the information gathered to determine, for instance, whether
2034 your system has unpatched security vulnerabilities.
2037 @cindex digital signatures
2038 @cindex substitutes, authorization thereof
2039 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2041 must add its public key to the access control list (ACL) of archive
2042 imports, using the @command{guix archive} command (@pxref{Invoking guix
2043 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2044 be compromised and to serve genuine substitutes.
2046 This public key is installed along with Guix, in
2047 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2048 the installation prefix of Guix. If you installed Guix from source,
2049 make sure you checked the GPG signature of
2050 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2051 Then, you can run something like this:
2054 # guix archive --authorize < hydra.gnu.org.pub
2057 Once this is in place, the output of a command like @code{guix build}
2058 should change from something like:
2061 $ guix build emacs --dry-run
2062 The following derivations would be built:
2063 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2064 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2065 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2066 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2074 $ guix build emacs --dry-run
2075 The following files would be downloaded:
2076 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2077 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2078 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2079 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2084 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2085 will be downloaded, when possible, for future builds.
2087 Guix ignores substitutes that are not signed, or that are not signed by
2088 one of the keys listed in the ACL. It also detects and raises an error
2089 when attempting to use a substitute that has been tampered with.
2092 Substitutes are downloaded over HTTP or HTTPS.
2093 The @code{http_proxy} environment
2094 variable can be set in the environment of @command{guix-daemon} and is
2095 honored for downloads of substitutes. Note that the value of
2096 @code{http_proxy} in the environment where @command{guix build},
2097 @command{guix package}, and other client commands are run has
2098 @emph{absolutely no effect}.
2100 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2101 (in other words, the server is not authenticated), contrary to what
2102 HTTPS clients such as Web browsers usually do. This is because Guix
2103 authenticates substitute information itself, as explained above, which
2104 is what we care about (whereas X.509 certificates are about
2105 authenticating bindings between domain names and public keys.)
2107 The substitute mechanism can be disabled globally by running
2108 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2109 guix-daemon}). It can also be disabled temporarily by passing the
2110 @code{--no-substitutes} option to @command{guix package}, @command{guix
2111 build}, and other command-line tools.
2114 @unnumberedsubsec On Trusting Binaries
2116 Today, each individual's control over their own computing is at the
2117 mercy of institutions, corporations, and groups with enough power and
2118 determination to subvert the computing infrastructure and exploit its
2119 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2120 convenient, we encourage users to also build on their own, or even run
2121 their own build farm, such that @code{hydra.gnu.org} is less of an
2122 interesting target. One way to help is by publishing the software you
2123 build using @command{guix publish} so that others have one more choice
2124 of server to download substitutes from (@pxref{Invoking guix publish}).
2126 Guix has the foundations to maximize build reproducibility
2127 (@pxref{Features}). In most cases, independent builds of a given
2128 package or derivation should yield bit-identical results. Thus, through
2129 a diverse set of independent package builds, we can strengthen the
2130 integrity of our systems. The @command{guix challenge} command aims to
2131 help users assess substitute servers, and to assist developers in
2132 finding out about non-deterministic package builds (@pxref{Invoking guix
2133 challenge}). Similarly, the @option{--check} option of @command{guix
2134 build} allows users to check whether previously-installed substitutes
2135 are genuine by rebuilding them locally (@pxref{build-check,
2136 @command{guix build --check}}).
2138 In the future, we want Guix to have support to publish and retrieve
2139 binaries to/from other users, in a peer-to-peer fashion. If you would
2140 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2143 @node Packages with Multiple Outputs
2144 @section Packages with Multiple Outputs
2146 @cindex multiple-output packages
2147 @cindex package outputs
2150 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2151 source package leads to exactly one directory in the store. When running
2152 @command{guix package -i glibc}, one installs the default output of the
2153 GNU libc package; the default output is called @code{out}, but its name
2154 can be omitted as shown in this command. In this particular case, the
2155 default output of @code{glibc} contains all the C header files, shared
2156 libraries, static libraries, Info documentation, and other supporting
2159 Sometimes it is more appropriate to separate the various types of files
2160 produced from a single source package into separate outputs. For
2161 instance, the GLib C library (used by GTK+ and related packages)
2162 installs more than 20 MiB of reference documentation as HTML pages.
2163 To save space for users who do not need it, the documentation goes to a
2164 separate output, called @code{doc}. To install the main GLib output,
2165 which contains everything but the documentation, one would run:
2168 guix package -i glib
2171 @cindex documentation
2172 The command to install its documentation is:
2175 guix package -i glib:doc
2178 Some packages install programs with different ``dependency footprints''.
2179 For instance, the WordNet package installs both command-line tools and
2180 graphical user interfaces (GUIs). The former depend solely on the C
2181 library, whereas the latter depend on Tcl/Tk and the underlying X
2182 libraries. In this case, we leave the command-line tools in the default
2183 output, whereas the GUIs are in a separate output. This allows users
2184 who do not need the GUIs to save space. The @command{guix size} command
2185 can help find out about such situations (@pxref{Invoking guix size}).
2186 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2188 There are several such multiple-output packages in the GNU distribution.
2189 Other conventional output names include @code{lib} for libraries and
2190 possibly header files, @code{bin} for stand-alone programs, and
2191 @code{debug} for debugging information (@pxref{Installing Debugging
2192 Files}). The outputs of a packages are listed in the third column of
2193 the output of @command{guix package --list-available} (@pxref{Invoking
2197 @node Invoking guix gc
2198 @section Invoking @command{guix gc}
2200 @cindex garbage collector
2202 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2203 The @command{guix gc} command allows users to explicitly run the garbage
2204 collector to reclaim space from the @file{/gnu/store} directory. It is
2205 the @emph{only} way to remove files from @file{/gnu/store}---removing
2206 files or directories manually may break it beyond repair!
2208 The garbage collector has a set of known @dfn{roots}: any file under
2209 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2210 cannot be deleted; any other file is considered @dfn{dead} and may be
2211 deleted. The set of garbage collector roots includes default user
2212 profiles, and may be augmented with @command{guix build --root}, for
2213 example (@pxref{Invoking guix build}).
2215 Prior to running @code{guix gc --collect-garbage} to make space, it is
2216 often useful to remove old generations from user profiles; that way, old
2217 package builds referenced by those generations can be reclaimed. This
2218 is achieved by running @code{guix package --delete-generations}
2219 (@pxref{Invoking guix package}).
2221 The @command{guix gc} command has three modes of operation: it can be
2222 used to garbage-collect any dead files (the default), to delete specific
2223 files (the @code{--delete} option), to print garbage-collector
2224 information, or for more advanced queries. The garbage collection
2225 options are as follows:
2228 @item --collect-garbage[=@var{min}]
2229 @itemx -C [@var{min}]
2230 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2231 sub-directories. This is the default operation when no option is
2234 When @var{min} is given, stop once @var{min} bytes have been collected.
2235 @var{min} may be a number of bytes, or it may include a unit as a
2236 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2237 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2239 When @var{min} is omitted, collect all the garbage.
2241 @item --free-space=@var{free}
2242 @itemx -F @var{free}
2243 Collect garbage until @var{free} space is available under
2244 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2245 as @code{500MiB}, as described above.
2247 When @var{free} or more is already available in @file{/gnu/store}, do
2248 nothing and exit immediately.
2252 Attempt to delete all the store files and directories specified as
2253 arguments. This fails if some of the files are not in the store, or if
2254 they are still live.
2256 @item --list-failures
2257 List store items corresponding to cached build failures.
2259 This prints nothing unless the daemon was started with
2260 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2261 @option{--cache-failures}}).
2263 @item --clear-failures
2264 Remove the specified store items from the failed-build cache.
2266 Again, this option only makes sense when the daemon is started with
2267 @option{--cache-failures}. Otherwise, it does nothing.
2270 Show the list of dead files and directories still present in the
2271 store---i.e., files and directories no longer reachable from any root.
2274 Show the list of live store files and directories.
2278 In addition, the references among existing store files can be queried:
2284 @cindex package dependencies
2285 List the references (respectively, the referrers) of store files given
2291 List the requisites of the store files passed as arguments. Requisites
2292 include the store files themselves, their references, and the references
2293 of these, recursively. In other words, the returned list is the
2294 @dfn{transitive closure} of the store files.
2296 @xref{Invoking guix size}, for a tool to profile the size of the closure
2297 of an element. @xref{Invoking guix graph}, for a tool to visualize
2298 the graph of references.
2302 Lastly, the following options allow you to check the integrity of the
2303 store and to control disk usage.
2307 @item --verify[=@var{options}]
2308 @cindex integrity, of the store
2309 @cindex integrity checking
2310 Verify the integrity of the store.
2312 By default, make sure that all the store items marked as valid in the
2313 database of the daemon actually exist in @file{/gnu/store}.
2315 When provided, @var{options} must be a comma-separated list containing one
2316 or more of @code{contents} and @code{repair}.
2318 When passing @option{--verify=contents}, the daemon computes the
2319 content hash of each store item and compares it against its hash in the
2320 database. Hash mismatches are reported as data corruptions. Because it
2321 traverses @emph{all the files in the store}, this command can take a
2322 long time, especially on systems with a slow disk drive.
2324 @cindex repairing the store
2325 @cindex corruption, recovering from
2326 Using @option{--verify=repair} or @option{--verify=contents,repair}
2327 causes the daemon to try to repair corrupt store items by fetching
2328 substitutes for them (@pxref{Substitutes}). Because repairing is not
2329 atomic, and thus potentially dangerous, it is available only to the
2330 system administrator. A lightweight alternative, when you know exactly
2331 which items in the store are corrupt, is @command{guix build --repair}
2332 (@pxref{Invoking guix build}).
2335 @cindex deduplication
2336 Optimize the store by hard-linking identical files---this is
2337 @dfn{deduplication}.
2339 The daemon performs deduplication after each successful build or archive
2340 import, unless it was started with @code{--disable-deduplication}
2341 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2342 this option is primarily useful when the daemon was running with
2343 @code{--disable-deduplication}.
2347 @node Invoking guix pull
2348 @section Invoking @command{guix pull}
2350 @cindex upgrading Guix
2351 @cindex updating Guix
2352 @cindex @command{guix pull}
2354 Packages are installed or upgraded to the latest version available in
2355 the distribution currently available on your local machine. To update
2356 that distribution, along with the Guix tools, you must run @command{guix
2357 pull}: the command downloads the latest Guix source code and package
2358 descriptions, and deploys it.
2360 On completion, @command{guix package} will use packages and package
2361 versions from this just-retrieved copy of Guix. Not only that, but all
2362 the Guix commands and Scheme modules will also be taken from that latest
2363 version. New @command{guix} sub-commands added by the update also
2366 Any user can update their Guix copy using @command{guix pull}, and the
2367 effect is limited to the user who run @command{guix pull}. For
2368 instance, when user @code{root} runs @command{guix pull}, this has no
2369 effect on the version of Guix that user @code{alice} sees, and vice
2370 versa@footnote{Under the hood, @command{guix pull} updates the
2371 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2372 and the @command{guix} command loads code from there. Currently, the
2373 only way to roll back an invocation of @command{guix pull} is to
2374 manually update this symlink to point to the previous Guix.}.
2376 The @command{guix pull} command is usually invoked with no arguments,
2377 but it supports the following options:
2381 Produce verbose output, writing build logs to the standard error output.
2383 @item --url=@var{url}
2384 Download the source tarball of Guix from @var{url}.
2386 By default, the tarball is taken from its canonical address at
2387 @code{gnu.org}, for the stable branch of Guix.
2389 With some Git servers, this can be used to deploy any version of Guix.
2390 For example, to download and deploy version 0.12.0 of Guix from the
2394 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2397 It can also be used to deploy arbitrary Git revisions:
2400 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2404 Use the bootstrap Guile to build the latest Guix. This option is only
2405 useful to Guix developers.
2408 In addition, @command{guix pull} supports all the common build options
2409 (@pxref{Common Build Options}).
2411 @node Invoking guix pack
2412 @section Invoking @command{guix pack}
2414 Occasionally you want to pass software to people who are not (yet!)
2415 lucky enough to be using Guix. You'd tell them to run @command{guix
2416 package -i @var{something}}, but that's not possible in this case. This
2417 is where @command{guix pack} comes in.
2421 @cindex application bundle
2422 @cindex software bundle
2423 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2424 @dfn{software bundle}: it creates a tarball or some other archive
2425 containing the binaries of the software you're interested in, and all
2426 its dependencies. The resulting archive can be used on any machine that
2427 does not have Guix, and people can run the exact same binaries as those
2428 you have with Guix. The pack itself is created in a bit-reproducible
2429 fashion, so anyone can verify that it really contains the build results
2430 that you pretend to be shipping.
2432 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2433 their dependencies, you can run:
2436 $ guix pack guile emacs geiser
2438 /gnu/store/@dots{}-pack.tar.gz
2441 The result here is a tarball containing a @file{/gnu/store} directory
2442 with all the relevant packages. The resulting tarball contains a
2443 @dfn{profile} with the three packages of interest; the profile is the
2444 same as would be created by @command{guix package -i}. It is this
2445 mechanism that is used to create Guix's own standalone binary tarball
2446 (@pxref{Binary Installation}).
2448 Users of this pack would have to run
2449 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2450 find inconvenient. To work around it, you can create, say, a
2451 @file{/opt/gnu/bin} symlink to the profile:
2454 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2458 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2460 Alternatively, you can produce a pack in the Docker image format using
2461 the following command:
2464 guix pack -f docker guile emacs geiser
2468 The result is a tarball that can be passed to the @command{docker load}
2470 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2471 documentation} for more information.
2473 Several command-line options allow you to customize your pack:
2476 @item --format=@var{format}
2477 @itemx -f @var{format}
2478 Produce a pack in the given @var{format}.
2480 The available formats are:
2484 This is the default format. It produces a tarball containing all the
2485 specifies binaries and symlinks.
2488 This produces a tarball that follows the
2489 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2490 Docker Image Specification}.
2493 @item --expression=@var{expr}
2494 @itemx -e @var{expr}
2495 Consider the package @var{expr} evaluates to.
2497 This has the same purpose as the same-named option in @command{guix
2498 build} (@pxref{Additional Build Options, @code{--expression} in
2499 @command{guix build}}).
2501 @item --system=@var{system}
2502 @itemx -s @var{system}
2503 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2504 the system type of the build host.
2506 @item --target=@var{triplet}
2507 @cindex cross-compilation
2508 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2509 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2510 configuration triplets,, autoconf, Autoconf}).
2512 @item --compression=@var{tool}
2513 @itemx -C @var{tool}
2514 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2515 @code{bzip2}, @code{xz}, or @code{lzip}.
2517 @item --symlink=@var{spec}
2518 @itemx -S @var{spec}
2519 Add the symlinks specified by @var{spec} to the pack. This option can
2520 appear several times.
2522 @var{spec} has the form @code{@var{source}=@var{target}}, where
2523 @var{source} is the symlink that will be created and @var{target} is the
2526 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2527 symlink pointing to the @file{bin} sub-directory of the profile.
2529 @item --localstatedir
2530 Include the ``local state directory'', @file{/var/guix}, in the
2533 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2534 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2535 the pack means that the store is ``complete'' and manageable by Guix;
2536 not providing it pack means that the store is ``dead'': items cannot be
2537 added to it or removed from it after extraction of the pack.
2539 One use case for this is the Guix self-contained binary tarball
2540 (@pxref{Binary Installation}).
2543 In addition, @command{guix pack} supports all the common build options
2544 (@pxref{Common Build Options}) and all the package transformation
2545 options (@pxref{Package Transformation Options}).
2548 @node Invoking guix archive
2549 @section Invoking @command{guix archive}
2551 @cindex @command{guix archive}
2553 The @command{guix archive} command allows users to @dfn{export} files
2554 from the store into a single archive, and to later @dfn{import} them.
2555 In particular, it allows store files to be transferred from one machine
2556 to the store on another machine.
2558 @cindex exporting store items
2559 To export store files as an archive to standard output, run:
2562 guix archive --export @var{options} @var{specifications}...
2565 @var{specifications} may be either store file names or package
2566 specifications, as for @command{guix package} (@pxref{Invoking guix
2567 package}). For instance, the following command creates an archive
2568 containing the @code{gui} output of the @code{git} package and the main
2569 output of @code{emacs}:
2572 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2575 If the specified packages are not built yet, @command{guix archive}
2576 automatically builds them. The build process may be controlled with the
2577 common build options (@pxref{Common Build Options}).
2579 To transfer the @code{emacs} package to a machine connected over SSH,
2583 guix archive --export -r emacs | ssh the-machine guix archive --import
2587 Similarly, a complete user profile may be transferred from one machine
2588 to another like this:
2591 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2592 ssh the-machine guix-archive --import
2596 However, note that, in both examples, all of @code{emacs} and the
2597 profile as well as all of their dependencies are transferred (due to
2598 @code{-r}), regardless of what is already available in the store on the
2599 target machine. The @code{--missing} option can help figure out which
2600 items are missing from the target store. The @command{guix copy}
2601 command simplifies and optimizes this whole process, so this is probably
2602 what you should use in this case (@pxref{Invoking guix copy}).
2604 @cindex nar, archive format
2605 @cindex normalized archive (nar)
2606 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2607 comparable in spirit to `tar', but with differences
2608 that make it more appropriate for our purposes. First, rather than
2609 recording all Unix metadata for each file, the nar format only mentions
2610 the file type (regular, directory, or symbolic link); Unix permissions
2611 and owner/group are dismissed. Second, the order in which directory
2612 entries are stored always follows the order of file names according to
2613 the C locale collation order. This makes archive production fully
2616 When exporting, the daemon digitally signs the contents of the archive,
2617 and that digital signature is appended. When importing, the daemon
2618 verifies the signature and rejects the import in case of an invalid
2619 signature or if the signing key is not authorized.
2620 @c FIXME: Add xref to daemon doc about signatures.
2622 The main options are:
2626 Export the specified store files or packages (see below.) Write the
2627 resulting archive to the standard output.
2629 Dependencies are @emph{not} included in the output, unless
2630 @code{--recursive} is passed.
2634 When combined with @code{--export}, this instructs @command{guix
2635 archive} to include dependencies of the given items in the archive.
2636 Thus, the resulting archive is self-contained: it contains the closure
2637 of the exported store items.
2640 Read an archive from the standard input, and import the files listed
2641 therein into the store. Abort if the archive has an invalid digital
2642 signature, or if it is signed by a public key not among the authorized
2643 keys (see @code{--authorize} below.)
2646 Read a list of store file names from the standard input, one per line,
2647 and write on the standard output the subset of these files missing from
2650 @item --generate-key[=@var{parameters}]
2651 @cindex signing, archives
2652 Generate a new key pair for the daemon. This is a prerequisite before
2653 archives can be exported with @code{--export}. Note that this operation
2654 usually takes time, because it needs to gather enough entropy to
2655 generate the key pair.
2657 The generated key pair is typically stored under @file{/etc/guix}, in
2658 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2659 key, which must be kept secret.) When @var{parameters} is omitted,
2660 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2661 versions before 1.6.0, it is a 4096-bit RSA key.
2662 Alternatively, @var{parameters} can specify
2663 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2664 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2665 Libgcrypt Reference Manual}).
2668 @cindex authorizing, archives
2669 Authorize imports signed by the public key passed on standard input.
2670 The public key must be in ``s-expression advanced format''---i.e., the
2671 same format as the @file{signing-key.pub} file.
2673 The list of authorized keys is kept in the human-editable file
2674 @file{/etc/guix/acl}. The file contains
2675 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2676 s-expressions''} and is structured as an access-control list in the
2677 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2680 @item --extract=@var{directory}
2681 @itemx -x @var{directory}
2682 Read a single-item archive as served by substitute servers
2683 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2684 low-level operation needed in only very narrow use cases; see below.
2686 For example, the following command extracts the substitute for Emacs
2687 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2691 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2692 | bunzip2 | guix archive -x /tmp/emacs
2695 Single-item archives are different from multiple-item archives produced
2696 by @command{guix archive --export}; they contain a single store item,
2697 and they do @emph{not} embed a signature. Thus this operation does
2698 @emph{no} signature verification and its output should be considered
2701 The primary purpose of this operation is to facilitate inspection of
2702 archive contents coming from possibly untrusted substitute servers.
2706 @c *********************************************************************
2707 @node Programming Interface
2708 @chapter Programming Interface
2710 GNU Guix provides several Scheme programming interfaces (APIs) to
2711 define, build, and query packages. The first interface allows users to
2712 write high-level package definitions. These definitions refer to
2713 familiar packaging concepts, such as the name and version of a package,
2714 its build system, and its dependencies. These definitions can then be
2715 turned into concrete build actions.
2717 Build actions are performed by the Guix daemon, on behalf of users. In a
2718 standard setup, the daemon has write access to the store---the
2719 @file{/gnu/store} directory---whereas users do not. The recommended
2720 setup also has the daemon perform builds in chroots, under a specific
2721 build users, to minimize interference with the rest of the system.
2724 Lower-level APIs are available to interact with the daemon and the
2725 store. To instruct the daemon to perform a build action, users actually
2726 provide it with a @dfn{derivation}. A derivation is a low-level
2727 representation of the build actions to be taken, and the environment in
2728 which they should occur---derivations are to package definitions what
2729 assembly is to C programs. The term ``derivation'' comes from the fact
2730 that build results @emph{derive} from them.
2732 This chapter describes all these APIs in turn, starting from high-level
2733 package definitions.
2736 * Defining Packages:: Defining new packages.
2737 * Build Systems:: Specifying how packages are built.
2738 * The Store:: Manipulating the package store.
2739 * Derivations:: Low-level interface to package derivations.
2740 * The Store Monad:: Purely functional interface to the store.
2741 * G-Expressions:: Manipulating build expressions.
2744 @node Defining Packages
2745 @section Defining Packages
2747 The high-level interface to package definitions is implemented in the
2748 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2749 example, the package definition, or @dfn{recipe}, for the GNU Hello
2750 package looks like this:
2753 (define-module (gnu packages hello)
2754 #:use-module (guix packages)
2755 #:use-module (guix download)
2756 #:use-module (guix build-system gnu)
2757 #:use-module (guix licenses)
2758 #:use-module (gnu packages gawk))
2760 (define-public hello
2766 (uri (string-append "mirror://gnu/hello/hello-" version
2770 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2771 (build-system gnu-build-system)
2772 (arguments '(#:configure-flags '("--enable-silent-rules")))
2773 (inputs `(("gawk" ,gawk)))
2774 (synopsis "Hello, GNU world: An example GNU package")
2775 (description "Guess what GNU Hello prints!")
2776 (home-page "http://www.gnu.org/software/hello/")
2781 Without being a Scheme expert, the reader may have guessed the meaning
2782 of the various fields here. This expression binds the variable
2783 @code{hello} to a @code{<package>} object, which is essentially a record
2784 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2785 This package object can be inspected using procedures found in the
2786 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2787 returns---surprise!---@code{"hello"}.
2789 With luck, you may be able to import part or all of the definition of
2790 the package you are interested in from another repository, using the
2791 @code{guix import} command (@pxref{Invoking guix import}).
2793 In the example above, @var{hello} is defined in a module of its own,
2794 @code{(gnu packages hello)}. Technically, this is not strictly
2795 necessary, but it is convenient to do so: all the packages defined in
2796 modules under @code{(gnu packages @dots{})} are automatically known to
2797 the command-line tools (@pxref{Package Modules}).
2799 There are a few points worth noting in the above package definition:
2803 The @code{source} field of the package is an @code{<origin>} object
2804 (@pxref{origin Reference}, for the complete reference).
2805 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2806 meaning that the source is a file to be downloaded over FTP or HTTP.
2808 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2809 the GNU mirrors defined in @code{(guix download)}.
2811 The @code{sha256} field specifies the expected SHA256 hash of the file
2812 being downloaded. It is mandatory, and allows Guix to check the
2813 integrity of the file. The @code{(base32 @dots{})} form introduces the
2814 base32 representation of the hash. You can obtain this information with
2815 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2816 hash} (@pxref{Invoking guix hash}).
2819 When needed, the @code{origin} form can also have a @code{patches} field
2820 listing patches to be applied, and a @code{snippet} field giving a
2821 Scheme expression to modify the source code.
2824 @cindex GNU Build System
2825 The @code{build-system} field specifies the procedure to build the
2826 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2827 represents the familiar GNU Build System, where packages may be
2828 configured, built, and installed with the usual @code{./configure &&
2829 make && make check && make install} command sequence.
2832 The @code{arguments} field specifies options for the build system
2833 (@pxref{Build Systems}). Here it is interpreted by
2834 @var{gnu-build-system} as a request run @file{configure} with the
2835 @code{--enable-silent-rules} flag.
2841 What about these quote (@code{'}) characters? They are Scheme syntax to
2842 introduce a literal list; @code{'} is synonymous with @code{quote}.
2843 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2844 for details. Here the value of the @code{arguments} field is a list of
2845 arguments passed to the build system down the road, as with @code{apply}
2846 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2849 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2850 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2851 @code{#:configure-flags} is a keyword used to pass a keyword argument
2852 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2856 The @code{inputs} field specifies inputs to the build process---i.e.,
2857 build-time or run-time dependencies of the package. Here, we define an
2858 input called @code{"gawk"} whose value is that of the @var{gawk}
2859 variable; @var{gawk} is itself bound to a @code{<package>} object.
2861 @cindex backquote (quasiquote)
2864 @cindex comma (unquote)
2868 @findex unquote-splicing
2869 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2870 us to introduce a literal list in the @code{inputs} field, while
2871 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2872 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2875 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2876 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2877 of ensuring that they are present (@pxref{Build Systems}).
2879 However, any other dependencies need to be specified in the
2880 @code{inputs} field. Any dependency not specified here will simply be
2881 unavailable to the build process, possibly leading to a build failure.
2884 @xref{package Reference}, for a full description of possible fields.
2886 Once a package definition is in place, the
2887 package may actually be built using the @code{guix build} command-line
2888 tool (@pxref{Invoking guix build}), troubleshooting any build failures
2889 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
2890 package definition using the @command{guix edit} command
2891 (@pxref{Invoking guix edit}).
2892 @xref{Packaging Guidelines}, for
2893 more information on how to test package definitions, and
2894 @ref{Invoking guix lint}, for information on how to check a definition
2895 for style conformance.
2896 @vindex GUIX_PACKAGE_PATH
2897 Lastly, @pxref{Package Modules}, for information
2898 on how to extend the distribution by adding your own package definitions
2899 to @code{GUIX_PACKAGE_PATH}.
2901 Finally, updating the package definition to a new upstream version
2902 can be partly automated by the @command{guix refresh} command
2903 (@pxref{Invoking guix refresh}).
2905 Behind the scenes, a derivation corresponding to the @code{<package>}
2906 object is first computed by the @code{package-derivation} procedure.
2907 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2908 The build actions it prescribes may then be realized by using the
2909 @code{build-derivations} procedure (@pxref{The Store}).
2911 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2912 Return the @code{<derivation>} object of @var{package} for @var{system}
2913 (@pxref{Derivations}).
2915 @var{package} must be a valid @code{<package>} object, and @var{system}
2916 must be a string denoting the target system type---e.g.,
2917 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2918 must be a connection to the daemon, which operates on the store
2919 (@pxref{The Store}).
2923 @cindex cross-compilation
2924 Similarly, it is possible to compute a derivation that cross-builds a
2925 package for some other system:
2927 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2928 @var{package} @var{target} [@var{system}]
2929 Return the @code{<derivation>} object of @var{package} cross-built from
2930 @var{system} to @var{target}.
2932 @var{target} must be a valid GNU triplet denoting the target hardware
2933 and operating system, such as @code{"mips64el-linux-gnu"}
2934 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2935 Configure and Build System}).
2938 @cindex package transformations
2939 @cindex input rewriting
2940 @cindex dependency tree rewriting
2941 Packages can be manipulated in arbitrary ways. An example of a useful
2942 transformation is @dfn{input rewriting}, whereby the dependency tree of
2943 a package is rewritten by replacing specific inputs by others:
2945 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2946 [@var{rewrite-name}]
2947 Return a procedure that, when passed a package, replaces its direct and
2948 indirect dependencies (but not its implicit inputs) according to
2949 @var{replacements}. @var{replacements} is a list of package pairs; the
2950 first element of each pair is the package to replace, and the second one
2953 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2954 the name of a package and returns its new name after rewrite.
2958 Consider this example:
2961 (define libressl-instead-of-openssl
2962 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2964 (package-input-rewriting `((,openssl . ,libressl))))
2966 (define git-with-libressl
2967 (libressl-instead-of-openssl git))
2971 Here we first define a rewriting procedure that replaces @var{openssl}
2972 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2973 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2974 This is exactly what the @option{--with-input} command-line option does
2975 (@pxref{Package Transformation Options, @option{--with-input}}).
2977 A more generic procedure to rewrite a package dependency graph is
2978 @code{package-mapping}: it supports arbitrary changes to nodes in the
2981 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
2982 Return a procedure that, given a package, applies @var{proc} to all the packages
2983 depended on and returns the resulting package. The procedure stops recursion
2984 when @var{cut?} returns true for a given package.
2988 * package Reference :: The package data type.
2989 * origin Reference:: The origin data type.
2993 @node package Reference
2994 @subsection @code{package} Reference
2996 This section summarizes all the options available in @code{package}
2997 declarations (@pxref{Defining Packages}).
2999 @deftp {Data Type} package
3000 This is the data type representing a package recipe.
3004 The name of the package, as a string.
3006 @item @code{version}
3007 The version of the package, as a string.
3010 An object telling how the source code for the package should be
3011 acquired. Most of the time, this is an @code{origin} object, which
3012 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3013 can also be any other ``file-like'' object such as a @code{local-file},
3014 which denotes a file from the local file system (@pxref{G-Expressions,
3015 @code{local-file}}).
3017 @item @code{build-system}
3018 The build system that should be used to build the package (@pxref{Build
3021 @item @code{arguments} (default: @code{'()})
3022 The arguments that should be passed to the build system. This is a
3023 list, typically containing sequential keyword-value pairs.
3025 @item @code{inputs} (default: @code{'()})
3026 @itemx @code{native-inputs} (default: @code{'()})
3027 @itemx @code{propagated-inputs} (default: @code{'()})
3028 @cindex inputs, of packages
3029 These fields list dependencies of the package. Each one is a list of
3030 tuples, where each tuple has a label for the input (a string) as its
3031 first element, a package, origin, or derivation as its second element,
3032 and optionally the name of the output thereof that should be used, which
3033 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3034 more on package outputs). For example, the list below specifies three
3038 `(("libffi" ,libffi)
3039 ("libunistring" ,libunistring)
3040 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3043 @cindex cross compilation, package dependencies
3044 The distinction between @code{native-inputs} and @code{inputs} is
3045 necessary when considering cross-compilation. When cross-compiling,
3046 dependencies listed in @code{inputs} are built for the @emph{target}
3047 architecture; conversely, dependencies listed in @code{native-inputs}
3048 are built for the architecture of the @emph{build} machine.
3050 @code{native-inputs} is typically used to list tools needed at
3051 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3052 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3053 this area (@pxref{Invoking guix lint}).
3055 @anchor{package-propagated-inputs}
3056 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3057 specified packages will be automatically installed alongside the package
3058 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3059 package}}, for information on how @command{guix package} deals with
3062 For example this is necessary when a C/C++ library needs headers of
3063 another library to compile, or when a pkg-config file refers to another
3064 one @i{via} its @code{Requires} field.
3066 Another example where @code{propagated-inputs} is useful is for languages
3067 that lack a facility to record the run-time search path akin to the
3068 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3069 more. To ensure that libraries written in those languages can find
3070 library code they depend on at run time, run-time dependencies must be
3071 listed in @code{propagated-inputs} rather than @code{inputs}.
3073 @item @code{self-native-input?} (default: @code{#f})
3074 This is a Boolean field telling whether the package should use itself as
3075 a native input when cross-compiling.
3077 @item @code{outputs} (default: @code{'("out")})
3078 The list of output names of the package. @xref{Packages with Multiple
3079 Outputs}, for typical uses of additional outputs.
3081 @item @code{native-search-paths} (default: @code{'()})
3082 @itemx @code{search-paths} (default: @code{'()})
3083 A list of @code{search-path-specification} objects describing
3084 search-path environment variables honored by the package.
3086 @item @code{replacement} (default: @code{#f})
3087 This must be either @code{#f} or a package object that will be used as a
3088 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3091 @item @code{synopsis}
3092 A one-line description of the package.
3094 @item @code{description}
3095 A more elaborate description of the package.
3097 @item @code{license}
3098 @cindex license, of packages
3099 The license of the package; a value from @code{(guix licenses)},
3100 or a list of such values.
3102 @item @code{home-page}
3103 The URL to the home-page of the package, as a string.
3105 @item @code{supported-systems} (default: @var{%supported-systems})
3106 The list of systems supported by the package, as strings of the form
3107 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3109 @item @code{maintainers} (default: @code{'()})
3110 The list of maintainers of the package, as @code{maintainer} objects.
3112 @item @code{location} (default: source location of the @code{package} form)
3113 The source location of the package. It is useful to override this when
3114 inheriting from another package, in which case this field is not
3115 automatically corrected.
3120 @node origin Reference
3121 @subsection @code{origin} Reference
3123 This section summarizes all the options available in @code{origin}
3124 declarations (@pxref{Defining Packages}).
3126 @deftp {Data Type} origin
3127 This is the data type representing a source code origin.
3131 An object containing the URI of the source. The object type depends on
3132 the @code{method} (see below). For example, when using the
3133 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3134 values are: a URL represented as a string, or a list thereof.
3137 A procedure that handles the URI.
3142 @item @var{url-fetch} from @code{(guix download)}
3143 download a file from the HTTP, HTTPS, or FTP URL specified in the
3147 @item @var{git-fetch} from @code{(guix git-download)}
3148 clone the Git version control repository, and check out the revision
3149 specified in the @code{uri} field as a @code{git-reference} object; a
3150 @code{git-reference} looks like this:
3154 (url "git://git.debian.org/git/pkg-shadow/shadow")
3155 (commit "v4.1.5.1"))
3160 A bytevector containing the SHA-256 hash of the source. Typically the
3161 @code{base32} form is used here to generate the bytevector from a
3164 You can obtain this information using @code{guix download}
3165 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3168 @item @code{file-name} (default: @code{#f})
3169 The file name under which the source code should be saved. When this is
3170 @code{#f}, a sensible default value will be used in most cases. In case
3171 the source is fetched from a URL, the file name from the URL will be
3172 used. For version control checkouts, it is recommended to provide the
3173 file name explicitly because the default is not very descriptive.
3175 @item @code{patches} (default: @code{'()})
3176 A list of file names containing patches to be applied to the source.
3178 This list of patches must be unconditional. In particular, it cannot
3179 depend on the value of @code{%current-system} or
3180 @code{%current-target-system}.
3182 @item @code{snippet} (default: @code{#f})
3183 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3184 in the source directory. This is a convenient way to modify the source,
3185 sometimes more convenient than a patch.
3187 @item @code{patch-flags} (default: @code{'("-p1")})
3188 A list of command-line flags that should be passed to the @code{patch}
3191 @item @code{patch-inputs} (default: @code{#f})
3192 Input packages or derivations to the patching process. When this is
3193 @code{#f}, the usual set of inputs necessary for patching are provided,
3194 such as GNU@tie{}Patch.
3196 @item @code{modules} (default: @code{'()})
3197 A list of Guile modules that should be loaded during the patching
3198 process and while running the code in the @code{snippet} field.
3200 @item @code{patch-guile} (default: @code{#f})
3201 The Guile package that should be used in the patching process. When
3202 this is @code{#f}, a sensible default is used.
3208 @section Build Systems
3210 @cindex build system
3211 Each package definition specifies a @dfn{build system} and arguments for
3212 that build system (@pxref{Defining Packages}). This @code{build-system}
3213 field represents the build procedure of the package, as well as implicit
3214 dependencies of that build procedure.
3216 Build systems are @code{<build-system>} objects. The interface to
3217 create and manipulate them is provided by the @code{(guix build-system)}
3218 module, and actual build systems are exported by specific modules.
3220 @cindex bag (low-level package representation)
3221 Under the hood, build systems first compile package objects to
3222 @dfn{bags}. A @dfn{bag} is like a package, but with less
3223 ornamentation---in other words, a bag is a lower-level representation of
3224 a package, which includes all the inputs of that package, including some
3225 that were implicitly added by the build system. This intermediate
3226 representation is then compiled to a derivation (@pxref{Derivations}).
3228 Build systems accept an optional list of @dfn{arguments}. In package
3229 definitions, these are passed @i{via} the @code{arguments} field
3230 (@pxref{Defining Packages}). They are typically keyword arguments
3231 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3232 Guile Reference Manual}). The value of these arguments is usually
3233 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3234 by the daemon (@pxref{Derivations}).
3236 The main build system is @var{gnu-build-system}, which implements the
3237 standard build procedure for GNU and many other packages. It
3238 is provided by the @code{(guix build-system gnu)} module.
3240 @defvr {Scheme Variable} gnu-build-system
3241 @var{gnu-build-system} represents the GNU Build System, and variants
3242 thereof (@pxref{Configuration, configuration and makefile conventions,,
3243 standards, GNU Coding Standards}).
3245 @cindex build phases
3246 In a nutshell, packages using it are configured, built, and installed with
3247 the usual @code{./configure && make && make check && make install}
3248 command sequence. In practice, a few additional steps are often needed.
3249 All these steps are split up in separate @dfn{phases},
3250 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3251 modules for more details about the build phases.}:
3255 Unpack the source tarball, and change the current directory to the
3256 extracted source tree. If the source is actually a directory, copy it
3257 to the build tree, and enter that directory.
3259 @item patch-source-shebangs
3260 Patch shebangs encountered in source files so they refer to the right
3261 store file names. For instance, this changes @code{#!/bin/sh} to
3262 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3265 Run the @file{configure} script with a number of default options, such
3266 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3267 by the @code{#:configure-flags} argument.
3270 Run @code{make} with the list of flags specified with
3271 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3272 (the default), build with @code{make -j}.
3275 Run @code{make check}, or some other target specified with
3276 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3277 @code{#:parallel-tests?} argument is true (the default), run @code{make
3281 Run @code{make install} with the flags listed in @code{#:make-flags}.
3283 @item patch-shebangs
3284 Patch shebangs on the installed executable files.
3287 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3288 is false), copying them to the @code{debug} output when available
3289 (@pxref{Installing Debugging Files}).
3292 @vindex %standard-phases
3293 The build-side module @code{(guix build gnu-build-system)} defines
3294 @var{%standard-phases} as the default list of build phases.
3295 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3296 procedure implements the actual phase.
3298 The list of phases used for a particular package can be changed with the
3299 @code{#:phases} parameter. For instance, passing:
3302 #:phases (modify-phases %standard-phases (delete 'configure))
3305 means that all the phases described above will be used, except the
3306 @code{configure} phase.
3308 In addition, this build system ensures that the ``standard'' environment
3309 for GNU packages is available. This includes tools such as GCC, libc,
3310 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3311 build-system gnu)} module for a complete list). We call these the
3312 @dfn{implicit inputs} of a package, because package definitions do not
3313 have to mention them.
3316 Other @code{<build-system>} objects are defined to support other
3317 conventions and tools used by free software packages. They inherit most
3318 of @var{gnu-build-system}, and differ mainly in the set of inputs
3319 implicitly added to the build process, and in the list of phases
3320 executed. Some of these build systems are listed below.
3322 @defvr {Scheme Variable} ant-build-system
3323 This variable is exported by @code{(guix build-system ant)}. It
3324 implements the build procedure for Java packages that can be built with
3325 @url{http://ant.apache.org/, Ant build tool}.
3327 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3328 provided by the @code{icedtea} package to the set of inputs. Different
3329 packages can be specified with the @code{#:ant} and @code{#:jdk}
3330 parameters, respectively.
3332 When the original package does not provide a suitable Ant build file,
3333 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3334 build file @file{build.xml} with tasks to build the specified jar
3335 archive. In this case the parameter @code{#:source-dir} can be used to
3336 specify the source sub-directory, defaulting to ``src''.
3338 The parameter @code{#:build-target} can be used to specify the Ant task
3339 that should be run during the @code{build} phase. By default the
3340 ``jar'' task will be run.
3344 @defvr {Scheme Variable} asdf-build-system/source
3345 @defvrx {Scheme Variable} asdf-build-system/sbcl
3346 @defvrx {Scheme Variable} asdf-build-system/ecl
3348 These variables, exported by @code{(guix build-system asdf)}, implement
3349 build procedures for Common Lisp packages using
3350 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3351 definition facility for Common Lisp programs and libraries.
3353 The @code{asdf-build-system/source} system installs the packages in
3354 source form, and can be loaded using any common lisp implementation, via
3355 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3356 systems in the format which a particular implementation understands.
3357 These build systems can also be used to produce executable programs, or
3358 lisp images which contain a set of packages pre-loaded.
3360 The build system uses naming conventions. For binary packages, the
3361 package name should be prefixed with the lisp implementation, such as
3362 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3364 Additionally, the corresponding source package should be labeled using
3365 the same convention as python packages (see @ref{Python Modules}), using
3366 the @code{cl-} prefix.
3368 For binary packages, each system should be defined as a Guix package.
3369 If one package @code{origin} contains several systems, package variants
3370 can be created in order to build all the systems. Source packages,
3371 which use @code{asdf-build-system/source}, may contain several systems.
3373 In order to create executable programs and images, the build-side
3374 procedures @code{build-program} and @code{build-image} can be used.
3375 They should be called in a build phase after the @code{create-symlinks}
3376 phase, so that the system which was just built can be used within the
3377 resulting image. @code{build-program} requires a list of Common Lisp
3378 expressions to be passed as the @code{#:entry-program} argument.
3380 If the system is not defined within its own @code{.asd} file of the same
3381 name, then the @code{#:asd-file} parameter should be used to specify
3382 which file the system is defined in. Furthermore, if the package
3383 defines a system for its tests in a separate file, it will be loaded
3384 before the tests are run if it is specified by the
3385 @code{#:test-asd-file} parameter. If it is not set, the files
3386 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3387 and @code{test.asd} will be tried if they exist.
3389 If for some reason the package must be named in a different way than the
3390 naming conventions suggest, the @code{#:asd-system-name} parameter can
3391 be used to specify the name of the system.
3395 @defvr {Scheme Variable} cargo-build-system
3396 @cindex Rust programming language
3397 @cindex Cargo (Rust build system)
3398 This variable is exported by @code{(guix build-system cargo)}. It
3399 supports builds of packages using Cargo, the build tool of the
3400 @uref{https://www.rust-lang.org, Rust programming language}.
3402 In its @code{configure} phase, this build system replaces dependencies
3403 specified in the @file{Carto.toml} file with inputs to the Guix package.
3404 The @code{install} phase installs the binaries, and it also installs the
3405 source code and @file{Cargo.toml} file.
3408 @defvr {Scheme Variable} cmake-build-system
3409 This variable is exported by @code{(guix build-system cmake)}. It
3410 implements the build procedure for packages using the
3411 @url{http://www.cmake.org, CMake build tool}.
3413 It automatically adds the @code{cmake} package to the set of inputs.
3414 Which package is used can be specified with the @code{#:cmake}
3417 The @code{#:configure-flags} parameter is taken as a list of flags
3418 passed to the @command{cmake} command. The @code{#:build-type}
3419 parameter specifies in abstract terms the flags passed to the compiler;
3420 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3421 debugging information''), which roughly means that code is compiled with
3422 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3425 @defvr {Scheme Variable} glib-or-gtk-build-system
3426 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3427 is intended for use with packages making use of GLib or GTK+.
3429 This build system adds the following two phases to the ones defined by
3430 @var{gnu-build-system}:
3433 @item glib-or-gtk-wrap
3434 The phase @code{glib-or-gtk-wrap} ensures that programs in
3435 @file{bin/} are able to find GLib ``schemas'' and
3436 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3437 modules}. This is achieved by wrapping the programs in launch scripts
3438 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3439 environment variables.
3441 It is possible to exclude specific package outputs from that wrapping
3442 process by listing their names in the
3443 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3444 when an output is known not to contain any GLib or GTK+ binaries, and
3445 where wrapping would gratuitously add a dependency of that output on
3448 @item glib-or-gtk-compile-schemas
3449 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3450 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3451 GSettings schemas} of GLib are compiled. Compilation is performed by the
3452 @command{glib-compile-schemas} program. It is provided by the package
3453 @code{glib:bin} which is automatically imported by the build system.
3454 The @code{glib} package providing @command{glib-compile-schemas} can be
3455 specified with the @code{#:glib} parameter.
3458 Both phases are executed after the @code{install} phase.
3461 @defvr {Scheme Variable} ocaml-build-system
3462 This variable is exported by @code{(guix build-system ocaml)}. It implements
3463 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3464 of choosing the correct set of commands to run for each package. OCaml
3465 packages can expect many different commands to be run. This build system will
3468 When the package has a @file{setup.ml} file present at the top-level, it will
3469 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3470 @code{ocaml setup.ml -install}. The build system will assume that this file
3471 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3472 care of setting the prefix and enabling tests if they are not disabled. You
3473 can pass configure and build flags with the @code{#:configure-flags} and
3474 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3475 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3476 bypass this system in the build and install phases.
3478 When the package has a @file{configure} file, it is assumed that it is a
3479 hand-made configure script that requires a different argument format than
3480 in the @code{gnu-build-system}. You can add more flags with the
3481 @code{#:configure-flags} key.
3483 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3484 @code{#t}), it will be used and more flags can be passed to the build and
3485 install phases with the @code{#:make-flags} key.
3487 Finally, some packages do not have these files and use a somewhat standard
3488 location for its build system. In that case, the build system will run
3489 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3490 providing the path to the required findlib module. Additional flags can
3491 be passed via the @code{#:build-flags} key. Install is taken care of by
3492 @command{opam-installer}. In this case, the @code{opam} package must
3493 be added to the @code{native-inputs} field of the package definition.
3495 Note that most OCaml packages assume they will be installed in the same
3496 directory as OCaml, which is not what we want in guix. In particular, they
3497 will install @file{.so} files in their module's directory, which is usually
3498 fine because it is in the OCaml compiler directory. In guix though, these
3499 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3500 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3501 @file{.so} libraries should be installed.
3504 @defvr {Scheme Variable} python-build-system
3505 This variable is exported by @code{(guix build-system python)}. It
3506 implements the more or less standard build procedure used by Python
3507 packages, which consists in running @code{python setup.py build} and
3508 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3510 For packages that install stand-alone Python programs under @code{bin/},
3511 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3512 environment variable points to all the Python libraries they depend on.
3514 Which Python package is used to perform the build can be specified with
3515 the @code{#:python} parameter. This is a useful way to force a package
3516 to be built for a specific version of the Python interpreter, which
3517 might be necessary if the package is only compatible with a single
3518 interpreter version.
3520 By default guix calls @code{setup.py} under control of
3521 @code{setuptools}, much like @command{pip} does. Some packages are not
3522 compatible with setuptools (and pip), thus you can disable this by
3523 setting the @code{#:use-setuptools} parameter to @code{#f}.
3526 @defvr {Scheme Variable} perl-build-system
3527 This variable is exported by @code{(guix build-system perl)}. It
3528 implements the standard build procedure for Perl packages, which either
3529 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3530 followed by @code{Build} and @code{Build install}; or in running
3531 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3532 @code{make} and @code{make install}, depending on which of
3533 @code{Build.PL} or @code{Makefile.PL} is present in the package
3534 distribution. Preference is given to the former if both @code{Build.PL}
3535 and @code{Makefile.PL} exist in the package distribution. This
3536 preference can be reversed by specifying @code{#t} for the
3537 @code{#:make-maker?} parameter.
3539 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3540 passes flags specified by the @code{#:make-maker-flags} or
3541 @code{#:module-build-flags} parameter, respectively.
3543 Which Perl package is used can be specified with @code{#:perl}.
3546 @defvr {Scheme Variable} r-build-system
3547 This variable is exported by @code{(guix build-system r)}. It
3548 implements the build procedure used by @uref{http://r-project.org, R}
3549 packages, which essentially is little more than running @code{R CMD
3550 INSTALL --library=/gnu/store/@dots{}} in an environment where
3551 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3552 are run after installation using the R function
3553 @code{tools::testInstalledPackage}.
3556 @defvr {Scheme Variable} ruby-build-system
3557 This variable is exported by @code{(guix build-system ruby)}. It
3558 implements the RubyGems build procedure used by Ruby packages, which
3559 involves running @code{gem build} followed by @code{gem install}.
3561 The @code{source} field of a package that uses this build system
3562 typically references a gem archive, since this is the format that Ruby
3563 developers use when releasing their software. The build system unpacks
3564 the gem archive, potentially patches the source, runs the test suite,
3565 repackages the gem, and installs it. Additionally, directories and
3566 tarballs may be referenced to allow building unreleased gems from Git or
3567 a traditional source release tarball.
3569 Which Ruby package is used can be specified with the @code{#:ruby}
3570 parameter. A list of additional flags to be passed to the @command{gem}
3571 command can be specified with the @code{#:gem-flags} parameter.
3574 @defvr {Scheme Variable} waf-build-system
3575 This variable is exported by @code{(guix build-system waf)}. It
3576 implements a build procedure around the @code{waf} script. The common
3577 phases---@code{configure}, @code{build}, and @code{install}---are
3578 implemented by passing their names as arguments to the @code{waf}
3581 The @code{waf} script is executed by the Python interpreter. Which
3582 Python package is used to run the script can be specified with the
3583 @code{#:python} parameter.
3586 @defvr {Scheme Variable} haskell-build-system
3587 This variable is exported by @code{(guix build-system haskell)}. It
3588 implements the Cabal build procedure used by Haskell packages, which
3589 involves running @code{runhaskell Setup.hs configure
3590 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3591 Instead of installing the package by running @code{runhaskell Setup.hs
3592 install}, to avoid trying to register libraries in the read-only
3593 compiler store directory, the build system uses @code{runhaskell
3594 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3595 addition, the build system generates the package documentation by
3596 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3597 is passed. Optional Haddock parameters can be passed with the help of
3598 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3599 not found, the build system looks for @code{Setup.lhs} instead.
3601 Which Haskell compiler is used can be specified with the @code{#:haskell}
3602 parameter which defaults to @code{ghc}.
3605 @defvr {Scheme Variable} dub-build-system
3606 This variable is exported by @code{(guix build-system dub)}. It
3607 implements the Dub build procedure used by D packages, which
3608 involves running @code{dub build} and @code{dub run}.
3609 Installation is done by copying the files manually.
3611 Which D compiler is used can be specified with the @code{#:ldc}
3612 parameter which defaults to @code{ldc}.
3615 @defvr {Scheme Variable} emacs-build-system
3616 This variable is exported by @code{(guix build-system emacs)}. It
3617 implements an installation procedure similar to the packaging system
3618 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3620 It first creates the @code{@var{package}-autoloads.el} file, then it
3621 byte compiles all Emacs Lisp files. Differently from the Emacs
3622 packaging system, the Info documentation files are moved to the standard
3623 documentation directory and the @file{dir} file is deleted. Each
3624 package is installed in its own directory under
3625 @file{share/emacs/site-lisp/guix.d}.
3628 Lastly, for packages that do not need anything as sophisticated, a
3629 ``trivial'' build system is provided. It is trivial in the sense that
3630 it provides basically no support: it does not pull any implicit inputs,
3631 and does not have a notion of build phases.
3633 @defvr {Scheme Variable} trivial-build-system
3634 This variable is exported by @code{(guix build-system trivial)}.
3636 This build system requires a @code{#:builder} argument. This argument
3637 must be a Scheme expression that builds the package output(s)---as
3638 with @code{build-expression->derivation} (@pxref{Derivations,
3639 @code{build-expression->derivation}}).
3649 Conceptually, the @dfn{store} is the place where derivations that have
3650 been built successfully are stored---by default, @file{/gnu/store}.
3651 Sub-directories in the store are referred to as @dfn{store items} or
3652 sometimes @dfn{store paths}. The store has an associated database that
3653 contains information such as the store paths referred to by each store
3654 path, and the list of @emph{valid} store items---results of successful
3655 builds. This database resides in @file{@var{localstatedir}/guix/db},
3656 where @var{localstatedir} is the state directory specified @i{via}
3657 @option{--localstatedir} at configure time, usually @file{/var}.
3659 The store is @emph{always} accessed by the daemon on behalf of its clients
3660 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3661 connect to the daemon over a Unix-domain socket, send requests to it,
3662 and read the result---these are remote procedure calls, or RPCs.
3665 Users must @emph{never} modify files under @file{/gnu/store} directly.
3666 This would lead to inconsistencies and break the immutability
3667 assumptions of Guix's functional model (@pxref{Introduction}).
3669 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3670 how to check the integrity of the store and attempt recovery from
3671 accidental modifications.
3674 The @code{(guix store)} module provides procedures to connect to the
3675 daemon, and to perform RPCs. These are described below. By default,
3676 @code{open-connection}, and thus all the @command{guix} commands,
3677 connect to the local daemon or to the URI specified by the
3678 @code{GUIX_DAEMON_SOCKET} environment variable.
3680 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3681 When set, the value of this variable should be a file name or a URI
3682 designating the daemon endpoint. When it is a file name, it denotes a
3683 Unix-domain socket to connect to. In addition to file names, the
3684 supported URI schemes are:
3689 These are for Unix-domain sockets.
3690 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3691 @file{/var/guix/daemon-socket/socket}.
3694 These URIs denote connections over TCP/IP, without encryption nor
3695 authentication of the remote host. The URI must always specify both the
3696 host name and port number:
3699 guix://master.guix.example.org:1234
3702 This setup is suitable on local networks, such as clusters, where only
3703 trusted nodes may connect to the build daemon at
3704 @code{master.guix.example.org}.
3707 @cindex SSH access to build daemons
3708 These URIs allow you to connect to a remote daemon over
3709 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3710 A typical URL might look like this:
3713 ssh://charlie@@guix.example.org:22
3716 As for @command{guix copy}, the usual OpenSSH client configuration files
3717 are honored (@pxref{Invoking guix copy}).
3720 Additional URI schemes may be supported in the future.
3722 @c XXX: Remove this note when the protocol incurs fewer round trips
3723 @c and when (guix derivations) no longer relies on file system access.
3725 The ability to connect to remote build daemons is considered
3726 experimental as of @value{VERSION}. Please get in touch with us to
3727 share any problems or suggestions you may have (@pxref{Contributing}).
3731 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3732 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3733 @var{reserve-space?} is true, instruct it to reserve a little bit of
3734 extra space on the file system so that the garbage collector can still
3735 operate should the disk become full. Return a server object.
3737 @var{file} defaults to @var{%default-socket-path}, which is the normal
3738 location given the options that were passed to @command{configure}.
3741 @deffn {Scheme Procedure} close-connection @var{server}
3742 Close the connection to @var{server}.
3745 @defvr {Scheme Variable} current-build-output-port
3746 This variable is bound to a SRFI-39 parameter, which refers to the port
3747 where build and error logs sent by the daemon should be written.
3750 Procedures that make RPCs all take a server object as their first
3753 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3754 @cindex invalid store items
3755 Return @code{#t} when @var{path} designates a valid store item and
3756 @code{#f} otherwise (an invalid item may exist on disk but still be
3757 invalid, for instance because it is the result of an aborted or failed
3760 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3761 prefixed by the store directory (@file{/gnu/store}).
3764 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3765 Add @var{text} under file @var{name} in the store, and return its store
3766 path. @var{references} is the list of store paths referred to by the
3767 resulting store path.
3770 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3771 Build @var{derivations} (a list of @code{<derivation>} objects or
3772 derivation paths), and return when the worker is done building them.
3773 Return @code{#t} on success.
3776 Note that the @code{(guix monads)} module provides a monad as well as
3777 monadic versions of the above procedures, with the goal of making it
3778 more convenient to work with code that accesses the store (@pxref{The
3782 @i{This section is currently incomplete.}
3785 @section Derivations
3788 Low-level build actions and the environment in which they are performed
3789 are represented by @dfn{derivations}. A derivation contains the
3790 following pieces of information:
3794 The outputs of the derivation---derivations produce at least one file or
3795 directory in the store, but may produce more.
3798 The inputs of the derivations, which may be other derivations or plain
3799 files in the store (patches, build scripts, etc.)
3802 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3805 The file name of a build script in the store, along with the arguments
3809 A list of environment variables to be defined.
3813 @cindex derivation path
3814 Derivations allow clients of the daemon to communicate build actions to
3815 the store. They exist in two forms: as an in-memory representation,
3816 both on the client- and daemon-side, and as files in the store whose
3817 name end in @code{.drv}---these files are referred to as @dfn{derivation
3818 paths}. Derivations paths can be passed to the @code{build-derivations}
3819 procedure to perform the build actions they prescribe (@pxref{The
3822 The @code{(guix derivations)} module provides a representation of
3823 derivations as Scheme objects, along with procedures to create and
3824 otherwise manipulate derivations. The lowest-level primitive to create
3825 a derivation is the @code{derivation} procedure:
3827 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3828 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3829 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3830 [#:system (%current-system)] [#:references-graphs #f] @
3831 [#:allowed-references #f] [#:disallowed-references #f] @
3832 [#:leaked-env-vars #f] [#:local-build? #f] @
3833 [#:substitutable? #t]
3834 Build a derivation with the given arguments, and return the resulting
3835 @code{<derivation>} object.
3837 When @var{hash} and @var{hash-algo} are given, a
3838 @dfn{fixed-output derivation} is created---i.e., one whose result is
3839 known in advance, such as a file download. If, in addition,
3840 @var{recursive?} is true, then that fixed output may be an executable
3841 file or a directory and @var{hash} must be the hash of an archive
3842 containing this output.
3844 When @var{references-graphs} is true, it must be a list of file
3845 name/store path pairs. In that case, the reference graph of each store
3846 path is exported in the build environment in the corresponding file, in
3847 a simple text format.
3849 When @var{allowed-references} is true, it must be a list of store items
3850 or outputs that the derivation's output may refer to. Likewise,
3851 @var{disallowed-references}, if true, must be a list of things the
3852 outputs may @emph{not} refer to.
3854 When @var{leaked-env-vars} is true, it must be a list of strings
3855 denoting environment variables that are allowed to ``leak'' from the
3856 daemon's environment to the build environment. This is only applicable
3857 to fixed-output derivations---i.e., when @var{hash} is true. The main
3858 use is to allow variables such as @code{http_proxy} to be passed to
3859 derivations that download files.
3861 When @var{local-build?} is true, declare that the derivation is not a
3862 good candidate for offloading and should rather be built locally
3863 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3864 where the costs of data transfers would outweigh the benefits.
3866 When @var{substitutable?} is false, declare that substitutes of the
3867 derivation's output should not be used (@pxref{Substitutes}). This is
3868 useful, for instance, when building packages that capture details of the
3869 host CPU instruction set.
3873 Here's an example with a shell script as its builder, assuming
3874 @var{store} is an open connection to the daemon, and @var{bash} points
3875 to a Bash executable in the store:
3878 (use-modules (guix utils)
3882 (let ((builder ; add the Bash script to the store
3883 (add-text-to-store store "my-builder.sh"
3884 "echo hello world > $out\n" '())))
3885 (derivation store "foo"
3886 bash `("-e" ,builder)
3887 #:inputs `((,bash) (,builder))
3888 #:env-vars '(("HOME" . "/homeless"))))
3889 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3892 As can be guessed, this primitive is cumbersome to use directly. A
3893 better approach is to write build scripts in Scheme, of course! The
3894 best course of action for that is to write the build code as a
3895 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3896 information, @pxref{G-Expressions}.
3898 Once upon a time, @code{gexp->derivation} did not exist and constructing
3899 derivations with build code written in Scheme was achieved with
3900 @code{build-expression->derivation}, documented below. This procedure
3901 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3903 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3904 @var{name} @var{exp} @
3905 [#:system (%current-system)] [#:inputs '()] @
3906 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3907 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3908 [#:references-graphs #f] [#:allowed-references #f] @
3909 [#:disallowed-references #f] @
3910 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3911 Return a derivation that executes Scheme expression @var{exp} as a
3912 builder for derivation @var{name}. @var{inputs} must be a list of
3913 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3914 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3915 modules from the current search path to be copied in the store,
3916 compiled, and made available in the load path during the execution of
3917 @var{exp}---e.g., @code{((guix build utils) (guix build
3918 gnu-build-system))}.
3920 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3921 to a list of output/path pairs, and where @code{%build-inputs} is bound
3922 to a list of string/output-path pairs made from @var{inputs}.
3923 Optionally, @var{env-vars} is a list of string pairs specifying the name
3924 and value of environment variables visible to the builder. The builder
3925 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3926 @var{exp} returns @code{#f}, the build is considered to have failed.
3928 @var{exp} is built using @var{guile-for-build} (a derivation). When
3929 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3930 @code{%guile-for-build} fluid is used instead.
3932 See the @code{derivation} procedure for the meaning of
3933 @var{references-graphs}, @var{allowed-references},
3934 @var{disallowed-references}, @var{local-build?}, and
3935 @var{substitutable?}.
3939 Here's an example of a single-output derivation that creates a directory
3940 containing one file:
3943 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3944 (mkdir out) ; create /gnu/store/@dots{}-goo
3945 (call-with-output-file (string-append out "/test")
3947 (display '(hello guix) p))))))
3948 (build-expression->derivation store "goo" builder))
3950 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3954 @node The Store Monad
3955 @section The Store Monad
3959 The procedures that operate on the store described in the previous
3960 sections all take an open connection to the build daemon as their first
3961 argument. Although the underlying model is functional, they either have
3962 side effects or depend on the current state of the store.
3964 The former is inconvenient: the connection to the build daemon has to be
3965 carried around in all those functions, making it impossible to compose
3966 functions that do not take that parameter with functions that do. The
3967 latter can be problematic: since store operations have side effects
3968 and/or depend on external state, they have to be properly sequenced.
3970 @cindex monadic values
3971 @cindex monadic functions
3972 This is where the @code{(guix monads)} module comes in. This module
3973 provides a framework for working with @dfn{monads}, and a particularly
3974 useful monad for our uses, the @dfn{store monad}. Monads are a
3975 construct that allows two things: associating ``context'' with values
3976 (in our case, the context is the store), and building sequences of
3977 computations (here computations include accesses to the store). Values
3978 in a monad---values that carry this additional context---are called
3979 @dfn{monadic values}; procedures that return such values are called
3980 @dfn{monadic procedures}.
3982 Consider this ``normal'' procedure:
3985 (define (sh-symlink store)
3986 ;; Return a derivation that symlinks the 'bash' executable.
3987 (let* ((drv (package-derivation store bash))
3988 (out (derivation->output-path drv))
3989 (sh (string-append out "/bin/bash")))
3990 (build-expression->derivation store "sh"
3991 `(symlink ,sh %output))))
3994 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3995 as a monadic function:
3998 (define (sh-symlink)
3999 ;; Same, but return a monadic value.
4000 (mlet %store-monad ((drv (package->derivation bash)))
4001 (gexp->derivation "sh"
4002 #~(symlink (string-append #$drv "/bin/bash")
4006 There are several things to note in the second version: the @code{store}
4007 parameter is now implicit and is ``threaded'' in the calls to the
4008 @code{package->derivation} and @code{gexp->derivation} monadic
4009 procedures, and the monadic value returned by @code{package->derivation}
4010 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4012 As it turns out, the call to @code{package->derivation} can even be
4013 omitted since it will take place implicitly, as we will see later
4014 (@pxref{G-Expressions}):
4017 (define (sh-symlink)
4018 (gexp->derivation "sh"
4019 #~(symlink (string-append #$bash "/bin/bash")
4024 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4025 @c for the funny quote.
4026 Calling the monadic @code{sh-symlink} has no effect. As someone once
4027 said, ``you exit a monad like you exit a building on fire: by running''.
4028 So, to exit the monad and get the desired effect, one must use
4029 @code{run-with-store}:
4032 (run-with-store (open-connection) (sh-symlink))
4033 @result{} /gnu/store/...-sh-symlink
4036 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4037 new ``meta-commands'' to make it easier to deal with monadic procedures:
4038 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4039 to ``run'' a single monadic value through the store:
4042 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4043 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4046 The latter enters a recursive REPL, where all the return values are
4047 automatically run through the store:
4050 scheme@@(guile-user)> ,enter-store-monad
4051 store-monad@@(guile-user) [1]> (package->derivation hello)
4052 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4053 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4054 $3 = "/gnu/store/@dots{}-foo"
4055 store-monad@@(guile-user) [1]> ,q
4056 scheme@@(guile-user)>
4060 Note that non-monadic values cannot be returned in the
4061 @code{store-monad} REPL.
4063 The main syntactic forms to deal with monads in general are provided by
4064 the @code{(guix monads)} module and are described below.
4066 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4067 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4071 @deffn {Scheme Syntax} return @var{val}
4072 Return a monadic value that encapsulates @var{val}.
4075 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4076 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4077 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4078 referred to as ``bind'', but that name denotes an unrelated procedure in
4079 Guile. Thus we use this somewhat cryptic symbol inherited from the
4080 Haskell language.}. There can be one @var{mproc} or several of them, as
4085 (with-monad %state-monad
4087 (lambda (x) (return (+ 1 x)))
4088 (lambda (x) (return (* 2 x)))))
4092 @result{} some-state
4096 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4098 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4100 Bind the variables @var{var} to the monadic values @var{mval} in
4101 @var{body}, which is a sequence of expressions. As with the bind
4102 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4103 value ``contained'' in @var{mval} and making @var{var} refer to that
4104 raw, non-monadic value within the scope of the @var{body}. The form
4105 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4106 @var{val}, as per @code{let}. The binding operations occur in sequence
4107 from left to right. The last expression of @var{body} must be a monadic
4108 expression, and its result will become the result of the @code{mlet} or
4109 @code{mlet*} when run in the @var{monad}.
4111 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4112 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4115 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4116 Bind @var{mexp} and the following monadic expressions in sequence,
4117 returning the result of the last expression. Every expression in the
4118 sequence must be a monadic expression.
4120 This is akin to @code{mlet}, except that the return values of the
4121 monadic expressions are ignored. In that sense, it is analogous to
4122 @code{begin}, but applied to monadic expressions.
4125 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4126 When @var{condition} is true, evaluate the sequence of monadic
4127 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4128 @var{condition} is false, return @code{*unspecified*} in the current
4129 monad. Every expression in the sequence must be a monadic expression.
4132 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4133 When @var{condition} is false, evaluate the sequence of monadic
4134 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4135 @var{condition} is true, return @code{*unspecified*} in the current
4136 monad. Every expression in the sequence must be a monadic expression.
4140 The @code{(guix monads)} module provides the @dfn{state monad}, which
4141 allows an additional value---the state---to be @emph{threaded} through
4142 monadic procedure calls.
4144 @defvr {Scheme Variable} %state-monad
4145 The state monad. Procedures in the state monad can access and change
4146 the state that is threaded.
4148 Consider the example below. The @code{square} procedure returns a value
4149 in the state monad. It returns the square of its argument, but also
4150 increments the current state value:
4154 (mlet %state-monad ((count (current-state)))
4155 (mbegin %state-monad
4156 (set-current-state (+ 1 count))
4159 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4164 When ``run'' through @var{%state-monad}, we obtain that additional state
4165 value, which is the number of @code{square} calls.
4168 @deffn {Monadic Procedure} current-state
4169 Return the current state as a monadic value.
4172 @deffn {Monadic Procedure} set-current-state @var{value}
4173 Set the current state to @var{value} and return the previous state as a
4177 @deffn {Monadic Procedure} state-push @var{value}
4178 Push @var{value} to the current state, which is assumed to be a list,
4179 and return the previous state as a monadic value.
4182 @deffn {Monadic Procedure} state-pop
4183 Pop a value from the current state and return it as a monadic value.
4184 The state is assumed to be a list.
4187 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4188 Run monadic value @var{mval} starting with @var{state} as the initial
4189 state. Return two values: the resulting value, and the resulting state.
4192 The main interface to the store monad, provided by the @code{(guix
4193 store)} module, is as follows.
4195 @defvr {Scheme Variable} %store-monad
4196 The store monad---an alias for @var{%state-monad}.
4198 Values in the store monad encapsulate accesses to the store. When its
4199 effect is needed, a value of the store monad must be ``evaluated'' by
4200 passing it to the @code{run-with-store} procedure (see below.)
4203 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4204 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4205 open store connection.
4208 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4209 Return as a monadic value the absolute file name in the store of the file
4210 containing @var{text}, a string. @var{references} is a list of store items that the
4211 resulting text file refers to; it defaults to the empty list.
4214 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4215 [#:recursive? #t] [#:select? (const #t)]
4216 Return the name of @var{file} once interned in the store. Use
4217 @var{name} as its store name, or the basename of @var{file} if
4218 @var{name} is omitted.
4220 When @var{recursive?} is true, the contents of @var{file} are added
4221 recursively; if @var{file} designates a flat file and @var{recursive?}
4222 is true, its contents are added, and its permission bits are kept.
4224 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4225 @var{stat})} for each directory entry, where @var{file} is the entry's
4226 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4227 entries for which @var{select?} does not return true.
4229 The example below adds a file to the store, under two different names:
4232 (run-with-store (open-connection)
4233 (mlet %store-monad ((a (interned-file "README"))
4234 (b (interned-file "README" "LEGU-MIN")))
4235 (return (list a b))))
4237 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4242 The @code{(guix packages)} module exports the following package-related
4245 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4246 [#:system (%current-system)] [#:target #f] @
4249 value in the absolute file name of @var{file} within the @var{output}
4250 directory of @var{package}. When @var{file} is omitted, return the name
4251 of the @var{output} directory of @var{package}. When @var{target} is
4252 true, use it as a cross-compilation target triplet.
4255 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4256 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4257 @var{target} [@var{system}]
4258 Monadic version of @code{package-derivation} and
4259 @code{package-cross-derivation} (@pxref{Defining Packages}).
4264 @section G-Expressions
4266 @cindex G-expression
4267 @cindex build code quoting
4268 So we have ``derivations'', which represent a sequence of build actions
4269 to be performed to produce an item in the store (@pxref{Derivations}).
4270 These build actions are performed when asking the daemon to actually
4271 build the derivations; they are run by the daemon in a container
4272 (@pxref{Invoking guix-daemon}).
4274 @cindex strata of code
4275 It should come as no surprise that we like to write these build actions
4276 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4277 code@footnote{The term @dfn{stratum} in this context was coined by
4278 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4279 Kiselyov, who has written insightful
4280 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4281 on this topic}, refers to this kind of code generation as
4282 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4283 to the daemon, etc.---and the ``build code''---code that actually
4284 performs build actions, such as making directories, invoking
4285 @command{make}, etc.
4287 To describe a derivation and its build actions, one typically needs to
4288 embed build code inside host code. It boils down to manipulating build
4289 code as data, and the homoiconicity of Scheme---code has a direct
4290 representation as data---comes in handy for that. But we need more than
4291 the normal @code{quasiquote} mechanism in Scheme to construct build
4294 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4295 S-expressions adapted to build expressions. G-expressions, or
4296 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4297 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4298 @code{#$}, and @code{#$@@}), which are comparable to
4299 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4300 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4301 GNU Guile Reference Manual}). However, there are major differences:
4305 Gexps are meant to be written to a file and run or manipulated by other
4309 When a high-level object such as a package or derivation is unquoted
4310 inside a gexp, the result is as if its output file name had been
4314 Gexps carry information about the packages or derivations they refer to,
4315 and these dependencies are automatically added as inputs to the build
4316 processes that use them.
4319 @cindex lowering, of high-level objects in gexps
4320 This mechanism is not limited to package and derivation
4321 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4322 derivations or files in the store can be defined,
4323 such that these objects can also be inserted
4324 into gexps. For example, a useful type of high-level objects that can be
4325 inserted in a gexp is ``file-like objects'', which make it easy to
4326 add files to the store and to refer to them in
4327 derivations and such (see @code{local-file} and @code{plain-file}
4330 To illustrate the idea, here is an example of a gexp:
4337 (symlink (string-append #$coreutils "/bin/ls")
4341 This gexp can be passed to @code{gexp->derivation}; we obtain a
4342 derivation that builds a directory containing exactly one symlink to
4343 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4346 (gexp->derivation "the-thing" build-exp)
4349 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4350 substituted to the reference to the @var{coreutils} package in the
4351 actual build code, and @var{coreutils} is automatically made an input to
4352 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4353 output)}) is replaced by a string containing the directory name of the
4354 output of the derivation.
4356 @cindex cross compilation
4357 In a cross-compilation context, it is useful to distinguish between
4358 references to the @emph{native} build of a package---that can run on the
4359 host---versus references to cross builds of a package. To that end, the
4360 @code{#+} plays the same role as @code{#$}, but is a reference to a
4361 native package build:
4364 (gexp->derivation "vi"
4367 (system* (string-append #+coreutils "/bin/ln")
4369 (string-append #$emacs "/bin/emacs")
4370 (string-append #$output "/bin/vi")))
4371 #:target "mips64el-linux-gnu")
4375 In the example above, the native build of @var{coreutils} is used, so
4376 that @command{ln} can actually run on the host; but then the
4377 cross-compiled build of @var{emacs} is referenced.
4379 @cindex imported modules, for gexps
4380 @findex with-imported-modules
4381 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4382 able to use certain Guile modules from the ``host environment'' in the
4383 gexp, so those modules should be imported in the ``build environment''.
4384 The @code{with-imported-modules} form allows you to express that:
4387 (let ((build (with-imported-modules '((guix build utils))
4389 (use-modules (guix build utils))
4390 (mkdir-p (string-append #$output "/bin"))))))
4391 (gexp->derivation "empty-dir"
4394 (display "success!\n")
4399 In this example, the @code{(guix build utils)} module is automatically
4400 pulled into the isolated build environment of our gexp, such that
4401 @code{(use-modules (guix build utils))} works as expected.
4403 @cindex module closure
4404 @findex source-module-closure
4405 Usually you want the @emph{closure} of the module to be imported---i.e.,
4406 the module itself and all the modules it depends on---rather than just
4407 the module; failing to do that, attempts to use the module will fail
4408 because of missing dependent modules. The @code{source-module-closure}
4409 procedure computes the closure of a module by looking at its source file
4410 headers, which comes in handy in this case:
4413 (use-modules (guix modules)) ;for 'source-module-closure'
4415 (with-imported-modules (source-module-closure
4416 '((guix build utils)
4418 (gexp->derivation "something-with-vms"
4420 (use-modules (guix build utils)
4425 The syntactic form to construct gexps is summarized below.
4427 @deffn {Scheme Syntax} #~@var{exp}
4428 @deffnx {Scheme Syntax} (gexp @var{exp})
4429 Return a G-expression containing @var{exp}. @var{exp} may contain one
4430 or more of the following forms:
4434 @itemx (ungexp @var{obj})
4435 Introduce a reference to @var{obj}. @var{obj} may have one of the
4436 supported types, for example a package or a
4437 derivation, in which case the @code{ungexp} form is replaced by its
4438 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4440 If @var{obj} is a list, it is traversed and references to supported
4441 objects are substituted similarly.
4443 If @var{obj} is another gexp, its contents are inserted and its
4444 dependencies are added to those of the containing gexp.
4446 If @var{obj} is another kind of object, it is inserted as is.
4448 @item #$@var{obj}:@var{output}
4449 @itemx (ungexp @var{obj} @var{output})
4450 This is like the form above, but referring explicitly to the
4451 @var{output} of @var{obj}---this is useful when @var{obj} produces
4452 multiple outputs (@pxref{Packages with Multiple Outputs}).
4455 @itemx #+@var{obj}:output
4456 @itemx (ungexp-native @var{obj})
4457 @itemx (ungexp-native @var{obj} @var{output})
4458 Same as @code{ungexp}, but produces a reference to the @emph{native}
4459 build of @var{obj} when used in a cross compilation context.
4461 @item #$output[:@var{output}]
4462 @itemx (ungexp output [@var{output}])
4463 Insert a reference to derivation output @var{output}, or to the main
4464 output when @var{output} is omitted.
4466 This only makes sense for gexps passed to @code{gexp->derivation}.
4469 @itemx (ungexp-splicing @var{lst})
4470 Like the above, but splices the contents of @var{lst} inside the
4474 @itemx (ungexp-native-splicing @var{lst})
4475 Like the above, but refers to native builds of the objects listed in
4480 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4481 of the @code{gexp?} type (see below.)
4484 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4485 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4486 in their execution environment.
4488 Each item in @var{modules} can be the name of a module, such as
4489 @code{(guix build utils)}, or it can be a module name, followed by an
4490 arrow, followed by a file-like object:
4493 `((guix build utils)
4495 ((guix config) => ,(scheme-file "config.scm"
4496 #~(define-module @dots{}))))
4500 In the example above, the first two modules are taken from the search
4501 path, and the last one is created from the given file-like object.
4503 This form has @emph{lexical} scope: it has an effect on the gexps
4504 directly defined in @var{body}@dots{}, but not on those defined, say, in
4505 procedures called from @var{body}@dots{}.
4508 @deffn {Scheme Procedure} gexp? @var{obj}
4509 Return @code{#t} if @var{obj} is a G-expression.
4512 G-expressions are meant to be written to disk, either as code building
4513 some derivation, or as plain files in the store. The monadic procedures
4514 below allow you to do that (@pxref{The Store Monad}, for more
4515 information about monads.)
4517 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4518 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4519 [#:hash #f] [#:hash-algo #f] @
4520 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4521 [#:module-path @var{%load-path}] @
4522 [#:references-graphs #f] [#:allowed-references #f] @
4523 [#:disallowed-references #f] @
4524 [#:leaked-env-vars #f] @
4525 [#:script-name (string-append @var{name} "-builder")] @
4526 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4527 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4528 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4529 stored in a file called @var{script-name}. When @var{target} is true,
4530 it is used as the cross-compilation target triplet for packages referred
4533 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4535 make @var{modules} available in the evaluation context of @var{exp};
4536 @var{modules} is a list of names of Guile modules searched in
4537 @var{module-path} to be copied in the store, compiled, and made available in
4538 the load path during the execution of @var{exp}---e.g., @code{((guix
4539 build utils) (guix build gnu-build-system))}.
4541 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4544 When @var{references-graphs} is true, it must be a list of tuples of one of the
4548 (@var{file-name} @var{package})
4549 (@var{file-name} @var{package} @var{output})
4550 (@var{file-name} @var{derivation})
4551 (@var{file-name} @var{derivation} @var{output})
4552 (@var{file-name} @var{store-item})
4555 The right-hand-side of each element of @var{references-graphs} is automatically made
4556 an input of the build process of @var{exp}. In the build environment, each
4557 @var{file-name} contains the reference graph of the corresponding item, in a simple
4560 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4561 In the latter case, the list denotes store items that the result is allowed to
4562 refer to. Any reference to another store item will lead to a build error.
4563 Similarly for @var{disallowed-references}, which can list items that must not be
4564 referenced by the outputs.
4566 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4569 @cindex file-like objects
4570 The @code{local-file}, @code{plain-file}, @code{computed-file},
4571 @code{program-file}, and @code{scheme-file} procedures below return
4572 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4573 these objects lead to a file in the store. Consider this G-expression:
4576 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4577 #$(local-file "/tmp/my-nscd.conf"))
4580 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4581 to the store. Once expanded, for instance @i{via}
4582 @code{gexp->derivation}, the G-expression refers to that copy under
4583 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4584 does not have any effect on what the G-expression does.
4585 @code{plain-file} can be used similarly; it differs in that the file
4586 content is directly passed as a string.
4588 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4589 [#:recursive? #f] [#:select? (const #t)]
4590 Return an object representing local file @var{file} to add to the store; this
4591 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4592 up relative to the source file where this form appears. @var{file} will be added to
4593 the store under @var{name}--by default the base name of @var{file}.
4595 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4596 designates a flat file and @var{recursive?} is true, its contents are added, and its
4597 permission bits are kept.
4599 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4600 @var{stat})} for each directory entry, where @var{file} is the entry's
4601 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4602 entries for which @var{select?} does not return true.
4604 This is the declarative counterpart of the @code{interned-file} monadic
4605 procedure (@pxref{The Store Monad, @code{interned-file}}).
4608 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4609 Return an object representing a text file called @var{name} with the given
4610 @var{content} (a string) to be added to the store.
4612 This is the declarative counterpart of @code{text-file}.
4615 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4616 [#:options '(#:local-build? #t)]
4617 Return an object representing the store item @var{name}, a file or
4618 directory computed by @var{gexp}. @var{options}
4619 is a list of additional arguments to pass to @code{gexp->derivation}.
4621 This is the declarative counterpart of @code{gexp->derivation}.
4624 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4625 Return an executable script @var{name} that runs @var{exp} using
4626 @var{guile}, with @var{exp}'s imported modules in its search path.
4628 The example below builds a script that simply invokes the @command{ls}
4632 (use-modules (guix gexp) (gnu packages base))
4634 (gexp->script "list-files"
4635 #~(execl #$(file-append coreutils "/bin/ls")
4639 When ``running'' it through the store (@pxref{The Store Monad,
4640 @code{run-with-store}}), we obtain a derivation that produces an
4641 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4644 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4646 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4650 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4652 Return an object representing the executable store item @var{name} that
4653 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4656 This is the declarative counterpart of @code{gexp->script}.
4659 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4660 [#:set-load-path? #t]
4661 Return a derivation that builds a file @var{name} containing @var{exp}.
4662 When @var{set-load-path?} is true, emit code in the resulting file to
4663 set @code{%load-path} and @code{%load-compiled-path} to honor
4664 @var{exp}'s imported modules.
4666 The resulting file holds references to all the dependencies of @var{exp}
4667 or a subset thereof.
4670 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4671 Return an object representing the Scheme file @var{name} that contains
4674 This is the declarative counterpart of @code{gexp->file}.
4677 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4678 Return as a monadic value a derivation that builds a text file
4679 containing all of @var{text}. @var{text} may list, in addition to
4680 strings, objects of any type that can be used in a gexp: packages,
4681 derivations, local file objects, etc. The resulting store file holds
4682 references to all these.
4684 This variant should be preferred over @code{text-file} anytime the file
4685 to create will reference items from the store. This is typically the
4686 case when building a configuration file that embeds store file names,
4690 (define (profile.sh)
4691 ;; Return the name of a shell script in the store that
4692 ;; initializes the 'PATH' environment variable.
4693 (text-file* "profile.sh"
4694 "export PATH=" coreutils "/bin:"
4695 grep "/bin:" sed "/bin\n"))
4698 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4699 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4700 preventing them from being garbage-collected during its lifetime.
4703 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4704 Return an object representing store file @var{name} containing
4705 @var{text}. @var{text} is a sequence of strings and file-like objects,
4709 (mixed-text-file "profile"
4710 "export PATH=" coreutils "/bin:" grep "/bin")
4713 This is the declarative counterpart of @code{text-file*}.
4716 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4717 Return a file-like object that expands to the concatenation of @var{obj}
4718 and @var{suffix}, where @var{obj} is a lowerable object and each
4719 @var{suffix} is a string.
4721 As an example, consider this gexp:
4724 (gexp->script "run-uname"
4725 #~(system* #$(file-append coreutils
4729 The same effect could be achieved with:
4732 (gexp->script "run-uname"
4733 #~(system* (string-append #$coreutils
4737 There is one difference though: in the @code{file-append} case, the
4738 resulting script contains the absolute file name as a string, whereas in
4739 the second case, the resulting script contains a @code{(string-append
4740 @dots{})} expression to construct the file name @emph{at run time}.
4744 Of course, in addition to gexps embedded in ``host'' code, there are
4745 also modules containing build tools. To make it clear that they are
4746 meant to be used in the build stratum, these modules are kept in the
4747 @code{(guix build @dots{})} name space.
4749 @cindex lowering, of high-level objects in gexps
4750 Internally, high-level objects are @dfn{lowered}, using their compiler,
4751 to either derivations or store items. For instance, lowering a package
4752 yields a derivation, and lowering a @code{plain-file} yields a store
4753 item. This is achieved using the @code{lower-object} monadic procedure.
4755 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4757 Return as a value in @var{%store-monad} the derivation or store item
4758 corresponding to @var{obj} for @var{system}, cross-compiling for
4759 @var{target} if @var{target} is true. @var{obj} must be an object that
4760 has an associated gexp compiler, such as a @code{<package>}.
4764 @c *********************************************************************
4768 This section describes Guix command-line utilities. Some of them are
4769 primarily targeted at developers and users who write new package
4770 definitions, while others are more generally useful. They complement
4771 the Scheme programming interface of Guix in a convenient way.
4774 * Invoking guix build:: Building packages from the command line.
4775 * Invoking guix edit:: Editing package definitions.
4776 * Invoking guix download:: Downloading a file and printing its hash.
4777 * Invoking guix hash:: Computing the cryptographic hash of a file.
4778 * Invoking guix import:: Importing package definitions.
4779 * Invoking guix refresh:: Updating package definitions.
4780 * Invoking guix lint:: Finding errors in package definitions.
4781 * Invoking guix size:: Profiling disk usage.
4782 * Invoking guix graph:: Visualizing the graph of packages.
4783 * Invoking guix environment:: Setting up development environments.
4784 * Invoking guix publish:: Sharing substitutes.
4785 * Invoking guix challenge:: Challenging substitute servers.
4786 * Invoking guix copy:: Copying to and from a remote store.
4787 * Invoking guix container:: Process isolation.
4790 @node Invoking guix build
4791 @section Invoking @command{guix build}
4793 @cindex package building
4794 @cindex @command{guix build}
4795 The @command{guix build} command builds packages or derivations and
4796 their dependencies, and prints the resulting store paths. Note that it
4797 does not modify the user's profile---this is the job of the
4798 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4799 it is mainly useful for distribution developers.
4801 The general syntax is:
4804 guix build @var{options} @var{package-or-derivation}@dots{}
4807 As an example, the following command builds the latest versions of Emacs
4808 and of Guile, displays their build logs, and finally displays the
4809 resulting directories:
4812 guix build emacs guile
4815 Similarly, the following command builds all the available packages:
4818 guix build --quiet --keep-going \
4819 `guix package -A | cut -f1,2 --output-delimiter=@@`
4822 @var{package-or-derivation} may be either the name of a package found in
4823 the software distribution such as @code{coreutils} or
4824 @code{coreutils@@8.20}, or a derivation such as
4825 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4826 package with the corresponding name (and optionally version) is searched
4827 for among the GNU distribution modules (@pxref{Package Modules}).
4829 Alternatively, the @code{--expression} option may be used to specify a
4830 Scheme expression that evaluates to a package; this is useful when
4831 disambiguating among several same-named packages or package variants is
4834 There may be zero or more @var{options}. The available options are
4835 described in the subsections below.
4838 * Common Build Options:: Build options for most commands.
4839 * Package Transformation Options:: Creating variants of packages.
4840 * Additional Build Options:: Options specific to 'guix build'.
4841 * Debugging Build Failures:: Real life packaging experience
4844 @node Common Build Options
4845 @subsection Common Build Options
4847 A number of options that control the build process are common to
4848 @command{guix build} and other commands that can spawn builds, such as
4849 @command{guix package} or @command{guix archive}. These are the
4854 @item --load-path=@var{directory}
4855 @itemx -L @var{directory}
4856 Add @var{directory} to the front of the package module search path
4857 (@pxref{Package Modules}).
4859 This allows users to define their own packages and make them visible to
4860 the command-line tools.
4864 Keep the build tree of failed builds. Thus, if a build fails, its build
4865 tree is kept under @file{/tmp}, in a directory whose name is shown at
4866 the end of the build log. This is useful when debugging build issues.
4867 @xref{Debugging Build Failures}, for tips and tricks on how to debug
4872 Keep going when some of the derivations fail to build; return only once
4873 all the builds have either completed or failed.
4875 The default behavior is to stop as soon as one of the specified
4876 derivations has failed.
4880 Do not build the derivations.
4883 When substituting a pre-built binary fails, fall back to building
4886 @item --substitute-urls=@var{urls}
4887 @anchor{client-substitute-urls}
4888 Consider @var{urls} the whitespace-separated list of substitute source
4889 URLs, overriding the default list of URLs of @command{guix-daemon}
4890 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4892 This means that substitutes may be downloaded from @var{urls}, provided
4893 they are signed by a key authorized by the system administrator
4894 (@pxref{Substitutes}).
4896 When @var{urls} is the empty string, substitutes are effectively
4899 @item --no-substitutes
4900 Do not use substitutes for build products. That is, always build things
4901 locally instead of allowing downloads of pre-built binaries
4902 (@pxref{Substitutes}).
4905 Do not ``graft'' packages. In practice, this means that package updates
4906 available as grafts are not applied. @xref{Security Updates}, for more
4907 information on grafts.
4909 @item --rounds=@var{n}
4910 Build each derivation @var{n} times in a row, and raise an error if
4911 consecutive build results are not bit-for-bit identical.
4913 This is a useful way to detect non-deterministic builds processes.
4914 Non-deterministic build processes are a problem because they make it
4915 practically impossible for users to @emph{verify} whether third-party
4916 binaries are genuine. @xref{Invoking guix challenge}, for more.
4918 Note that, currently, the differing build results are not kept around,
4919 so you will have to manually investigate in case of an error---e.g., by
4920 stashing one of the build results with @code{guix archive --export}
4921 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4924 @item --no-build-hook
4925 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4926 (@pxref{Daemon Offload Setup}). That is, always build things locally
4927 instead of offloading builds to remote machines.
4929 @item --max-silent-time=@var{seconds}
4930 When the build or substitution process remains silent for more than
4931 @var{seconds}, terminate it and report a build failure.
4933 @item --timeout=@var{seconds}
4934 Likewise, when the build or substitution process lasts for more than
4935 @var{seconds}, terminate it and report a build failure.
4937 By default there is no timeout. This behavior can be restored with
4940 @item --verbosity=@var{level}
4941 Use the given verbosity level. @var{level} must be an integer between 0
4942 and 5; higher means more verbose output. Setting a level of 4 or more
4943 may be helpful when debugging setup issues with the build daemon.
4945 @item --cores=@var{n}
4947 Allow the use of up to @var{n} CPU cores for the build. The special
4948 value @code{0} means to use as many CPU cores as available.
4950 @item --max-jobs=@var{n}
4952 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4953 guix-daemon, @code{--max-jobs}}, for details about this option and the
4954 equivalent @command{guix-daemon} option.
4958 Behind the scenes, @command{guix build} is essentially an interface to
4959 the @code{package-derivation} procedure of the @code{(guix packages)}
4960 module, and to the @code{build-derivations} procedure of the @code{(guix
4961 derivations)} module.
4963 In addition to options explicitly passed on the command line,
4964 @command{guix build} and other @command{guix} commands that support
4965 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4967 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4968 Users can define this variable to a list of command line options that
4969 will automatically be used by @command{guix build} and other
4970 @command{guix} commands that can perform builds, as in the example
4974 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4977 These options are parsed independently, and the result is appended to
4978 the parsed command-line options.
4982 @node Package Transformation Options
4983 @subsection Package Transformation Options
4985 @cindex package variants
4986 Another set of command-line options supported by @command{guix build}
4987 and also @command{guix package} are @dfn{package transformation
4988 options}. These are options that make it possible to define @dfn{package
4989 variants}---for instance, packages built from different source code.
4990 This is a convenient way to create customized packages on the fly
4991 without having to type in the definitions of package variants
4992 (@pxref{Defining Packages}).
4996 @item --with-source=@var{source}
4997 Use @var{source} as the source of the corresponding package.
4998 @var{source} must be a file name or a URL, as for @command{guix
4999 download} (@pxref{Invoking guix download}).
5001 The ``corresponding package'' is taken to be the one specified on the
5002 command line the name of which matches the base of @var{source}---e.g.,
5003 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5004 package is @code{guile}. Likewise, the version string is inferred from
5005 @var{source}; in the previous example, it is @code{2.0.10}.
5007 This option allows users to try out versions of packages other than the
5008 one provided by the distribution. The example below downloads
5009 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5010 the @code{ed} package:
5013 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5016 As a developer, @code{--with-source} makes it easy to test release
5020 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5023 @dots{} or to build from a checkout in a pristine environment:
5026 $ git clone git://git.sv.gnu.org/guix.git
5027 $ guix build guix --with-source=./guix
5030 @item --with-input=@var{package}=@var{replacement}
5031 Replace dependency on @var{package} by a dependency on
5032 @var{replacement}. @var{package} must be a package name, and
5033 @var{replacement} must be a package specification such as @code{guile}
5034 or @code{guile@@1.8}.
5036 For instance, the following command builds Guix, but replaces its
5037 dependency on the current stable version of Guile with a dependency on
5038 the legacy version of Guile, @code{guile@@2.0}:
5041 guix build --with-input=guile=guile@@2.0 guix
5044 This is a recursive, deep replacement. So in this example, both
5045 @code{guix} and its dependency @code{guile-json} (which also depends on
5046 @code{guile}) get rebuilt against @code{guile@@2.0}.
5048 This is implemented using the @code{package-input-rewriting} Scheme
5049 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5051 @item --with-graft=@var{package}=@var{replacement}
5052 This is similar to @code{--with-input} but with an important difference:
5053 instead of rebuilding the whole dependency chain, @var{replacement} is
5054 built and then @dfn{grafted} onto the binaries that were initially
5055 referring to @var{package}. @xref{Security Updates}, for more
5056 information on grafts.
5058 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5059 and all its dependencies, replacing references to the version of GnuTLS
5060 they currently refer to:
5063 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5066 This has the advantage of being much faster than rebuilding everything.
5067 But there is a caveat: it works if and only if @var{package} and
5068 @var{replacement} are strictly compatible---for example, if they provide
5069 a library, the application binary interface (ABI) of those libraries
5070 must be compatible. If @var{replacement} is somehow incompatible with
5071 @var{package}, then the resulting package may be unusable. Use with
5076 @node Additional Build Options
5077 @subsection Additional Build Options
5079 The command-line options presented below are specific to @command{guix
5086 Build quietly, without displaying the build log. Upon completion, the
5087 build log is kept in @file{/var} (or similar) and can always be
5088 retrieved using the @option{--log-file} option.
5090 @item --file=@var{file}
5091 @itemx -f @var{file}
5093 Build the package or derivation that the code within @var{file}
5096 As an example, @var{file} might contain a package definition like this
5097 (@pxref{Defining Packages}):
5100 @verbatiminclude package-hello.scm
5103 @item --expression=@var{expr}
5104 @itemx -e @var{expr}
5105 Build the package or derivation @var{expr} evaluates to.
5107 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5108 guile-1.8)}, which unambiguously designates this specific variant of
5109 version 1.8 of Guile.
5111 Alternatively, @var{expr} may be a G-expression, in which case it is used
5112 as a build program passed to @code{gexp->derivation}
5113 (@pxref{G-Expressions}).
5115 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5116 (@pxref{The Store Monad}). The procedure must return a derivation as a
5117 monadic value, which is then passed through @code{run-with-store}.
5121 Build the source derivations of the packages, rather than the packages
5124 For instance, @code{guix build -S gcc} returns something like
5125 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5128 The returned source tarball is the result of applying any patches and
5129 code snippets specified in the package @code{origin} (@pxref{Defining
5133 Fetch and return the source of @var{package-or-derivation} and all their
5134 dependencies, recursively. This is a handy way to obtain a local copy
5135 of all the source code needed to build @var{packages}, allowing you to
5136 eventually build them even without network access. It is an extension
5137 of the @code{--source} option and can accept one of the following
5138 optional argument values:
5142 This value causes the @code{--sources} option to behave in the same way
5143 as the @code{--source} option.
5146 Build the source derivations of all packages, including any source that
5147 might be listed as @code{inputs}. This is the default value.
5150 $ guix build --sources tzdata
5151 The following derivations will be built:
5152 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5153 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5157 Build the source derivations of all packages, as well of all transitive
5158 inputs to the packages. This can be used e.g. to
5159 prefetch package source for later offline building.
5162 $ guix build --sources=transitive tzdata
5163 The following derivations will be built:
5164 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5165 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5166 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5167 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5168 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5169 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5175 @item --system=@var{system}
5176 @itemx -s @var{system}
5177 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5178 the system type of the build host.
5180 An example use of this is on Linux-based systems, which can emulate
5181 different personalities. For instance, passing
5182 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5183 to build packages in a complete 32-bit environment.
5185 @item --target=@var{triplet}
5186 @cindex cross-compilation
5187 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5188 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5189 configuration triplets,, autoconf, Autoconf}).
5191 @anchor{build-check}
5193 @cindex determinism, checking
5194 @cindex reproducibility, checking
5195 Rebuild @var{package-or-derivation}, which are already available in the
5196 store, and raise an error if the build results are not bit-for-bit
5199 This mechanism allows you to check whether previously installed
5200 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5201 of a package is deterministic. @xref{Invoking guix challenge}, for more
5202 background information and tools.
5204 When used in conjunction with @option{--keep-failed}, the differing
5205 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5206 This makes it easy to look for differences between the two results.
5209 @cindex repairing store items
5210 @cindex corruption, recovering from
5211 Attempt to repair the specified store items, if they are corrupt, by
5212 re-downloading or rebuilding them.
5214 This operation is not atomic and thus restricted to @code{root}.
5218 Return the derivation paths, not the output paths, of the given
5221 @item --root=@var{file}
5222 @itemx -r @var{file}
5223 Make @var{file} a symlink to the result, and register it as a garbage
5227 Return the build log file names or URLs for the given
5228 @var{package-or-derivation}, or raise an error if build logs are
5231 This works regardless of how packages or derivations are specified. For
5232 instance, the following invocations are equivalent:
5235 guix build --log-file `guix build -d guile`
5236 guix build --log-file `guix build guile`
5237 guix build --log-file guile
5238 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5241 If a log is unavailable locally, and unless @code{--no-substitutes} is
5242 passed, the command looks for a corresponding log on one of the
5243 substitute servers (as specified with @code{--substitute-urls}.)
5245 So for instance, imagine you want to see the build log of GDB on MIPS,
5246 but you are actually on an @code{x86_64} machine:
5249 $ guix build --log-file gdb -s mips64el-linux
5250 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5253 You can freely access a huge library of build logs!
5256 @node Debugging Build Failures
5257 @subsection Debugging Build Failures
5259 @cindex build failures, debugging
5260 When defining a new package (@pxref{Defining Packages}), you will
5261 probably find yourself spending some time debugging and tweaking the
5262 build until it succeeds. To do that, you need to operate the build
5263 commands yourself in an environment as close as possible to the one the
5266 To that end, the first thing to do is to use the @option{--keep-failed}
5267 or @option{-K} option of @command{guix build}, which will keep the
5268 failed build tree in @file{/tmp} or whatever directory you specified as
5269 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5271 From there on, you can @command{cd} to the failed build tree and source
5272 the @file{environment-variables} file, which contains all the
5273 environment variable definitions that were in place when the build
5274 failed. So let's say you're debugging a build failure in package
5275 @code{foo}; a typical session would look like this:
5279 @dots{} @i{build fails}
5280 $ cd /tmp/guix-build-foo.drv-0
5281 $ source ./environment-variables
5285 Now, you can invoke commands as if you were the daemon (almost) and
5286 troubleshoot your build process.
5288 Sometimes it happens that, for example, a package's tests pass when you
5289 run them manually but they fail when the daemon runs them. This can
5290 happen because the daemon runs builds in containers where, unlike in our
5291 environment above, network access is missing, @file{/bin/sh} does not
5292 exist, etc. (@pxref{Build Environment Setup}).
5294 In such cases, you may need to run inspect the build process from within
5295 a container similar to the one the build daemon creates:
5300 $ cd /tmp/guix-build-foo.drv-0
5301 $ guix environment -C foo --ad-hoc strace gdb
5302 [env]# source ./environment-variables
5306 Here, @command{guix environment -C} creates a container and spawns a new
5307 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5308 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5309 the container, which would may find handy while debugging.
5311 To get closer to a container like that used by the build daemon, we can
5312 remove @file{/bin/sh}:
5318 (Don't worry, this is harmless: this is all happening in the throw-away
5319 container created by @command{guix environment}.)
5321 The @command{strace} command is probably not in the search path, but we
5325 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5328 In this way, not only you will have reproduced the environment variables
5329 the daemon uses, you will also be running the build process in a container
5330 similar to the one the daemon uses.
5333 @node Invoking guix edit
5334 @section Invoking @command{guix edit}
5336 @cindex @command{guix edit}
5337 @cindex package definition, editing
5338 So many packages, so many source files! The @command{guix edit} command
5339 facilitates the life of users and packagers by pointing their editor at
5340 the source file containing the definition of the specified packages.
5344 guix edit gcc@@4.9 vim
5348 launches the program specified in the @code{VISUAL} or in the
5349 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5352 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5353 have created your own packages on @code{GUIX_PACKAGE_PATH}
5354 (@pxref{Defining Packages}), you will be able to edit the package
5355 recipes. Otherwise, you will be able to examine the read-only recipes
5356 for packages currently in the store.
5359 @node Invoking guix download
5360 @section Invoking @command{guix download}
5362 @cindex @command{guix download}
5363 @cindex downloading package sources
5364 When writing a package definition, developers typically need to download
5365 a source tarball, compute its SHA256 hash, and write that
5366 hash in the package definition (@pxref{Defining Packages}). The
5367 @command{guix download} tool helps with this task: it downloads a file
5368 from the given URI, adds it to the store, and prints both its file name
5369 in the store and its SHA256 hash.
5371 The fact that the downloaded file is added to the store saves bandwidth:
5372 when the developer eventually tries to build the newly defined package
5373 with @command{guix build}, the source tarball will not have to be
5374 downloaded again because it is already in the store. It is also a
5375 convenient way to temporarily stash files, which may be deleted
5376 eventually (@pxref{Invoking guix gc}).
5378 The @command{guix download} command supports the same URIs as used in
5379 package definitions. In particular, it supports @code{mirror://} URIs.
5380 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5381 Guile bindings for GnuTLS are available in the user's environment; when
5382 they are not available, an error is raised. @xref{Guile Preparations,
5383 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5384 GnuTLS-Guile}, for more information.
5386 @command{guix download} verifies HTTPS server certificates by loading
5387 the certificates of X.509 authorities from the directory pointed to by
5388 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5389 Certificates}), unless @option{--no-check-certificate} is used.
5391 The following options are available:
5394 @item --format=@var{fmt}
5396 Write the hash in the format specified by @var{fmt}. For more
5397 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5399 @item --no-check-certificate
5400 Do not validate the X.509 certificates of HTTPS servers.
5402 When using this option, you have @emph{absolutely no guarantee} that you
5403 are communicating with the authentic server responsible for the given
5404 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5406 @item --output=@var{file}
5407 @itemx -o @var{file}
5408 Save the downloaded file to @var{file} instead of adding it to the
5412 @node Invoking guix hash
5413 @section Invoking @command{guix hash}
5415 @cindex @command{guix hash}
5416 The @command{guix hash} command computes the SHA256 hash of a file.
5417 It is primarily a convenience tool for anyone contributing to the
5418 distribution: it computes the cryptographic hash of a file, which can be
5419 used in the definition of a package (@pxref{Defining Packages}).
5421 The general syntax is:
5424 guix hash @var{option} @var{file}
5427 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5428 hash of data read from standard input. @command{guix hash} has the
5433 @item --format=@var{fmt}
5435 Write the hash in the format specified by @var{fmt}.
5437 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5438 (@code{hex} and @code{hexadecimal} can be used as well).
5440 If the @option{--format} option is not specified, @command{guix hash}
5441 will output the hash in @code{nix-base32}. This representation is used
5442 in the definitions of packages.
5446 Compute the hash on @var{file} recursively.
5448 In this case, the hash is computed on an archive containing @var{file},
5449 including its children if it is a directory. Some of the metadata of
5450 @var{file} is part of the archive; for instance, when @var{file} is a
5451 regular file, the hash is different depending on whether @var{file} is
5452 executable or not. Metadata such as time stamps has no impact on the
5453 hash (@pxref{Invoking guix archive}).
5454 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5459 When combined with @option{--recursive}, exclude version control system
5460 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5463 As an example, here is how you would compute the hash of a Git checkout,
5464 which is useful when using the @code{git-fetch} method (@pxref{origin
5468 $ git clone http://example.org/foo.git
5474 @node Invoking guix import
5475 @section Invoking @command{guix import}
5477 @cindex importing packages
5478 @cindex package import
5479 @cindex package conversion
5480 @cindex Invoking @command{guix import}
5481 The @command{guix import} command is useful for people who would like to
5482 add a package to the distribution with as little work as
5483 possible---a legitimate demand. The command knows of a few
5484 repositories from which it can ``import'' package metadata. The result
5485 is a package definition, or a template thereof, in the format we know
5486 (@pxref{Defining Packages}).
5488 The general syntax is:
5491 guix import @var{importer} @var{options}@dots{}
5494 @var{importer} specifies the source from which to import package
5495 metadata, and @var{options} specifies a package identifier and other
5496 options specific to @var{importer}. Currently, the available
5501 Import metadata for the given GNU package. This provides a template
5502 for the latest version of that GNU package, including the hash of its
5503 source tarball, and its canonical synopsis and description.
5505 Additional information such as the package dependencies and its
5506 license needs to be figured out manually.
5508 For example, the following command returns a package definition for
5512 guix import gnu hello
5515 Specific command-line options are:
5518 @item --key-download=@var{policy}
5519 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5520 keys when verifying the package signature. @xref{Invoking guix
5521 refresh, @code{--key-download}}.
5526 Import metadata from the @uref{https://pypi.python.org/, Python Package
5527 Index}@footnote{This functionality requires Guile-JSON to be installed.
5528 @xref{Requirements}.}. Information is taken from the JSON-formatted
5529 description available at @code{pypi.python.org} and usually includes all
5530 the relevant information, including package dependencies. For maximum
5531 efficiency, it is recommended to install the @command{unzip} utility, so
5532 that the importer can unzip Python wheels and gather data from them.
5534 The command below imports metadata for the @code{itsdangerous} Python
5538 guix import pypi itsdangerous
5543 Import metadata from @uref{https://rubygems.org/,
5544 RubyGems}@footnote{This functionality requires Guile-JSON to be
5545 installed. @xref{Requirements}.}. Information is taken from the
5546 JSON-formatted description available at @code{rubygems.org} and includes
5547 most relevant information, including runtime dependencies. There are
5548 some caveats, however. The metadata doesn't distinguish between
5549 synopses and descriptions, so the same string is used for both fields.
5550 Additionally, the details of non-Ruby dependencies required to build
5551 native extensions is unavailable and left as an exercise to the
5554 The command below imports metadata for the @code{rails} Ruby package:
5557 guix import gem rails
5562 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5563 functionality requires Guile-JSON to be installed.
5564 @xref{Requirements}.}.
5565 Information is taken from the JSON-formatted metadata provided through
5566 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5567 relevant information, such as module dependencies. License information
5568 should be checked closely. If Perl is available in the store, then the
5569 @code{corelist} utility will be used to filter core modules out of the
5570 list of dependencies.
5572 The command command below imports metadata for the @code{Acme::Boolean}
5576 guix import cpan Acme::Boolean
5581 @cindex Bioconductor
5582 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5583 central repository for the @uref{http://r-project.org, GNU@tie{}R
5584 statistical and graphical environment}.
5586 Information is extracted from the @code{DESCRIPTION} file of the package.
5588 The command command below imports metadata for the @code{Cairo}
5592 guix import cran Cairo
5595 When @code{--recursive} is added, the importer will traverse the
5596 dependency graph of the given upstream package recursively and generate
5597 package expressions for all those packages that are not yet in Guix.
5599 When @code{--archive=bioconductor} is added, metadata is imported from
5600 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5601 packages for for the analysis and comprehension of high-throughput
5602 genomic data in bioinformatics.
5604 Information is extracted from the @code{DESCRIPTION} file of a package
5605 published on the web interface of the Bioconductor SVN repository.
5607 The command below imports metadata for the @code{GenomicRanges}
5611 guix import cran --archive=bioconductor GenomicRanges
5615 Import metadata from a local copy of the source of the
5616 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5617 relies on the @command{nix-instantiate} command of
5618 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5619 typically written in a mixture of Nix-language and Bash code. This
5620 command only imports the high-level package structure that is written in
5621 the Nix language. It normally includes all the basic fields of a
5624 When importing a GNU package, the synopsis and descriptions are replaced
5625 by their canonical upstream variant.
5627 Usually, you will first need to do:
5630 export NIX_REMOTE=daemon
5634 so that @command{nix-instantiate} does not try to open the Nix database.
5636 As an example, the command below imports the package definition of
5637 LibreOffice (more precisely, it imports the definition of the package
5638 bound to the @code{libreoffice} top-level attribute):
5641 guix import nix ~/path/to/nixpkgs libreoffice
5646 Import metadata from the Haskell community's central package archive
5647 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5648 Cabal files and includes all the relevant information, including package
5651 Specific command-line options are:
5656 Read a Cabal file from standard input.
5657 @item --no-test-dependencies
5659 Do not include dependencies required only by the test suites.
5660 @item --cabal-environment=@var{alist}
5661 @itemx -e @var{alist}
5662 @var{alist} is a Scheme alist defining the environment in which the
5663 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5664 @code{arch}, @code{impl} and a string representing the name of a flag.
5665 The value associated with a flag has to be either the symbol
5666 @code{true} or @code{false}. The value associated with other keys
5667 has to conform to the Cabal file format definition. The default value
5668 associated with the keys @code{os}, @code{arch} and @code{impl} is
5669 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5672 The command below imports metadata for the latest version of the
5673 @code{HTTP} Haskell package without including test dependencies and
5674 specifying the value of the flag @samp{network-uri} as @code{false}:
5677 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5680 A specific package version may optionally be specified by following the
5681 package name by an at-sign and a version number as in the following example:
5684 guix import hackage mtl@@2.1.3.1
5689 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5690 It takes a package name, looks up the package version included in a
5691 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5692 release and uses the @code{hackage} importer to retrieve its metadata.
5693 Note that it is up to you to select an LTS release compatible with the
5694 GHC compiler used by Guix.
5696 Specific command-line options are:
5699 @item --no-test-dependencies
5701 Do not include dependencies required only by the test suites.
5702 @item --lts-version=@var{version}
5703 @itemx -r @var{version}
5704 @var{version} is the desired LTS release version. If omitted the latest
5708 The command below imports metadata for the @code{HTTP} Haskell package
5709 included in the LTS Stackage release version 7.18:
5712 guix import stackage --lts-version=7.18 HTTP
5717 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5718 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5720 Specific command-line options are:
5723 @item --archive=@var{repo}
5724 @itemx -a @var{repo}
5725 @var{repo} identifies the archive repository from which to retrieve the
5726 information. Currently the supported repositories and their identifiers
5730 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5731 identifier. This is the default.
5733 Packages from @code{elpa.gnu.org} are signed with one of the keys
5734 contained in the GnuPG keyring at
5735 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5736 @code{emacs} package (@pxref{Package Installation, ELPA package
5737 signatures,, emacs, The GNU Emacs Manual}).
5740 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5741 @code{melpa-stable} identifier.
5744 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5751 Import metadata from the crates.io Rust package repository
5752 @uref{https://crates.io, crates.io}.
5755 The structure of the @command{guix import} code is modular. It would be
5756 useful to have more importers for other package formats, and your help
5757 is welcome here (@pxref{Contributing}).
5759 @node Invoking guix refresh
5760 @section Invoking @command{guix refresh}
5762 @cindex @command {guix refresh}
5763 The primary audience of the @command{guix refresh} command is developers
5764 of the GNU software distribution. By default, it reports any packages
5765 provided by the distribution that are outdated compared to the latest
5766 upstream version, like this:
5770 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5771 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5774 Alternately, one can specify packages to consider, in which case a
5775 warning is emitted for packages that lack an updater:
5778 $ guix refresh coreutils guile guile-ssh
5779 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5780 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5783 @command{guix refresh} browses the upstream repository of each package and determines
5784 the highest version number of the releases therein. The command
5785 knows how to update specific types of packages: GNU packages, ELPA
5786 packages, etc.---see the documentation for @option{--type} below. There
5787 are many packages, though, for which it lacks a method to determine
5788 whether a new upstream release is available. However, the mechanism is
5789 extensible, so feel free to get in touch with us to add a new method!
5791 When passed @code{--update}, it modifies distribution source files to
5792 update the version numbers and source tarball hashes of those package
5793 recipes (@pxref{Defining Packages}). This is achieved by downloading
5794 each package's latest source tarball and its associated OpenPGP
5795 signature, authenticating the downloaded tarball against its signature
5796 using @command{gpg}, and finally computing its hash. When the public
5797 key used to sign the tarball is missing from the user's keyring, an
5798 attempt is made to automatically retrieve it from a public key server;
5799 when this is successful, the key is added to the user's keyring; otherwise,
5800 @command{guix refresh} reports an error.
5802 The following options are supported:
5806 @item --expression=@var{expr}
5807 @itemx -e @var{expr}
5808 Consider the package @var{expr} evaluates to.
5810 This is useful to precisely refer to a package, as in this example:
5813 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5816 This command lists the dependents of the ``final'' libc (essentially all
5821 Update distribution source files (package recipes) in place. This is
5822 usually run from a checkout of the Guix source tree (@pxref{Running
5823 Guix Before It Is Installed}):
5826 $ ./pre-inst-env guix refresh -s non-core -u
5829 @xref{Defining Packages}, for more information on package definitions.
5831 @item --select=[@var{subset}]
5832 @itemx -s @var{subset}
5833 Select all the packages in @var{subset}, one of @code{core} or
5836 The @code{core} subset refers to all the packages at the core of the
5837 distribution---i.e., packages that are used to build ``everything
5838 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5839 changing one of these packages in the distribution entails a rebuild of
5840 all the others. Thus, such updates are an inconvenience to users in
5841 terms of build time or bandwidth used to achieve the upgrade.
5843 The @code{non-core} subset refers to the remaining packages. It is
5844 typically useful in cases where an update of the core packages would be
5847 @item --type=@var{updater}
5848 @itemx -t @var{updater}
5849 Select only packages handled by @var{updater} (may be a comma-separated
5850 list of updaters). Currently, @var{updater} may be one of:
5854 the updater for GNU packages;
5856 the updater for GNOME packages;
5858 the updater for KDE packages;
5860 the updater for X.org packages;
5862 the updater for packages hosted on kernel.org;
5864 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5866 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5868 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5870 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5872 the updater for @uref{https://pypi.python.org, PyPI} packages.
5874 the updater for @uref{https://rubygems.org, RubyGems} packages.
5876 the updater for @uref{https://github.com, GitHub} packages.
5878 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5880 the updater for @uref{https://www.stackage.org, Stackage} packages.
5882 the updater for @uref{https://crates.io, Crates} packages.
5885 For instance, the following command only checks for updates of Emacs
5886 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5889 $ guix refresh --type=elpa,cran
5890 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5891 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5896 In addition, @command{guix refresh} can be passed one or more package
5897 names, as in this example:
5900 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5904 The command above specifically updates the @code{emacs} and
5905 @code{idutils} packages. The @code{--select} option would have no
5906 effect in this case.
5908 When considering whether to upgrade a package, it is sometimes
5909 convenient to know which packages would be affected by the upgrade and
5910 should be checked for compatibility. For this the following option may
5911 be used when passing @command{guix refresh} one or more package names:
5915 @item --list-updaters
5917 List available updaters and exit (see @option{--type} above.)
5919 For each updater, display the fraction of packages it covers; at the
5920 end, display the fraction of packages covered by all these updaters.
5922 @item --list-dependent
5924 List top-level dependent packages that would need to be rebuilt as a
5925 result of upgrading one or more packages.
5927 @xref{Invoking guix graph, the @code{reverse-package} type of
5928 @command{guix graph}}, for information on how to visualize the list of
5929 dependents of a package.
5933 Be aware that the @code{--list-dependent} option only
5934 @emph{approximates} the rebuilds that would be required as a result of
5935 an upgrade. More rebuilds might be required under some circumstances.
5938 $ guix refresh --list-dependent flex
5939 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5940 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
5943 The command above lists a set of packages that could be built to check
5944 for compatibility with an upgraded @code{flex} package.
5946 The following options can be used to customize GnuPG operation:
5950 @item --gpg=@var{command}
5951 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5952 for in @code{$PATH}.
5954 @item --key-download=@var{policy}
5955 Handle missing OpenPGP keys according to @var{policy}, which may be one
5960 Always download missing OpenPGP keys from the key server, and add them
5961 to the user's GnuPG keyring.
5964 Never try to download missing OpenPGP keys. Instead just bail out.
5967 When a package signed with an unknown OpenPGP key is encountered, ask
5968 the user whether to download it or not. This is the default behavior.
5971 @item --key-server=@var{host}
5972 Use @var{host} as the OpenPGP key server when importing a public key.
5976 The @code{github} updater uses the
5977 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5978 releases. When used repeatedly e.g. when refreshing all packages,
5979 GitHub will eventually refuse to answer any further API requests. By
5980 default 60 API requests per hour are allowed, and a full refresh on all
5981 GitHub packages in Guix requires more than this. Authentication with
5982 GitHub through the use of an API token alleviates these limits. To use
5983 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5984 token procured from @uref{https://github.com/settings/tokens} or
5988 @node Invoking guix lint
5989 @section Invoking @command{guix lint}
5991 @cindex @command{guix lint}
5992 @cindex package, checking for errors
5993 The @command{guix lint} command is meant to help package developers avoid
5994 common errors and use a consistent style. It runs a number of checks on
5995 a given set of packages in order to find common mistakes in their
5996 definitions. Available @dfn{checkers} include (see
5997 @code{--list-checkers} for a complete list):
6002 Validate certain typographical and stylistic rules about package
6003 descriptions and synopses.
6005 @item inputs-should-be-native
6006 Identify inputs that should most likely be native inputs.
6011 @itemx source-file-name
6012 Probe @code{home-page} and @code{source} URLs and report those that are
6013 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6014 the source file name is meaningful, e.g. is not
6015 just a version number or ``git-checkout'', without a declared
6016 @code{file-name} (@pxref{origin Reference}).
6019 @cindex security vulnerabilities
6020 @cindex CVE, Common Vulnerabilities and Exposures
6021 Report known vulnerabilities found in the Common Vulnerabilities and
6022 Exposures (CVE) databases of the current and past year
6023 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6026 To view information about a particular vulnerability, visit pages such as:
6030 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6032 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6036 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6037 @code{CVE-2015-7554}.
6039 Package developers can specify in package recipes the
6040 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6041 name and version of the package when they differ from the name that Guix
6042 uses, as in this example:
6048 ;; CPE calls this package "grub2".
6049 (properties '((cpe-name . "grub2"))))
6053 Warn about obvious source code formatting issues: trailing white space,
6054 use of tabulations, etc.
6057 The general syntax is:
6060 guix lint @var{options} @var{package}@dots{}
6063 If no package is given on the command line, then all packages are checked.
6064 The @var{options} may be zero or more of the following:
6067 @item --list-checkers
6069 List and describe all the available checkers that will be run on packages
6074 Only enable the checkers specified in a comma-separated list using the
6075 names returned by @code{--list-checkers}.
6079 @node Invoking guix size
6080 @section Invoking @command{guix size}
6083 @cindex package size
6085 @cindex @command{guix size}
6086 The @command{guix size} command helps package developers profile the
6087 disk usage of packages. It is easy to overlook the impact of an
6088 additional dependency added to a package, or the impact of using a
6089 single output for a package that could easily be split (@pxref{Packages
6090 with Multiple Outputs}). Such are the typical issues that
6091 @command{guix size} can highlight.
6093 The command can be passed a package specification such as @code{gcc@@4.8}
6094 or @code{guile:debug}, or a file name in the store. Consider this
6098 $ guix size coreutils
6099 store item total self
6100 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6101 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6102 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6103 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6104 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6105 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6109 The store items listed here constitute the @dfn{transitive closure} of
6110 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6111 would be returned by:
6114 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6117 Here the output shows three columns next to store items. The first column,
6118 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6119 the store item---that is, its own size plus the size of all its
6120 dependencies. The next column, labeled ``self'', shows the size of the
6121 item itself. The last column shows the ratio of the size of the item
6122 itself to the space occupied by all the items listed here.
6124 In this example, we see that the closure of Coreutils weighs in at
6125 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6126 large fraction of the closure is not a problem @i{per se} because it is
6127 always available on the system anyway.)
6129 When the package passed to @command{guix size} is available in the
6130 store, @command{guix size} queries the daemon to determine its
6131 dependencies, and measures its size in the store, similar to @command{du
6132 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6135 When the given package is @emph{not} in the store, @command{guix size}
6136 reports information based on the available substitutes
6137 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6138 store items that are not even on disk, only available remotely.
6140 You can also specify several package names:
6143 $ guix size coreutils grep sed bash
6144 store item total self
6145 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6146 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6147 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6148 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6154 In this example we see that the combination of the four packages takes
6155 102.3@tie{}MiB in total, which is much less than the sum of each closure
6156 since they have a lot of dependencies in common.
6158 The available options are:
6162 @item --substitute-urls=@var{urls}
6163 Use substitute information from @var{urls}.
6164 @xref{client-substitute-urls, the same option for @code{guix build}}.
6166 @item --map-file=@var{file}
6167 Write a graphical map of disk usage in PNG format to @var{file}.
6169 For the example above, the map looks like this:
6171 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6172 produced by @command{guix size}}
6174 This option requires that
6175 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6176 installed and visible in Guile's module search path. When that is not
6177 the case, @command{guix size} fails as it tries to load it.
6179 @item --system=@var{system}
6180 @itemx -s @var{system}
6181 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6185 @node Invoking guix graph
6186 @section Invoking @command{guix graph}
6189 @cindex @command{guix graph}
6190 @cindex package dependencies
6191 Packages and their dependencies form a @dfn{graph}, specifically a
6192 directed acyclic graph (DAG). It can quickly become difficult to have a
6193 mental model of the package DAG, so the @command{guix graph} command
6194 provides a visual representation of the DAG. By default,
6195 @command{guix graph} emits a DAG representation in the input format of
6196 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6197 directly to the @command{dot} command of Graphviz. It can also emit an
6198 HTML page with embedded JavaScript code to display a ``chord diagram''
6199 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6200 emit Cypher queries to construct a graph in a graph database supporting
6201 the @uref{http://www.opencypher.org/, openCypher} query language.
6202 The general syntax is:
6205 guix graph @var{options} @var{package}@dots{}
6208 For example, the following command generates a PDF file representing the
6209 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6213 guix graph coreutils | dot -Tpdf > dag.pdf
6216 The output looks like this:
6218 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6220 Nice little graph, no?
6222 But there is more than one graph! The one above is concise: it is the
6223 graph of package objects, omitting implicit inputs such as GCC, libc,
6224 grep, etc. It is often useful to have such a concise graph, but
6225 sometimes one may want to see more details. @command{guix graph} supports
6226 several types of graphs, allowing you to choose the level of detail:
6230 This is the default type used in the example above. It shows the DAG of
6231 package objects, excluding implicit dependencies. It is concise, but
6232 filters out many details.
6234 @item reverse-package
6235 This shows the @emph{reverse} DAG of packages. For example:
6238 guix graph --type=reverse-package ocaml
6241 ... yields the graph of packages that depend on OCaml.
6243 Note that for core packages this can yield huge graphs. If all you want
6244 is to know the number of packages that depend on a given package, use
6245 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6246 @option{--list-dependent}}).
6249 This is the package DAG, @emph{including} implicit inputs.
6251 For instance, the following command:
6254 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6257 ... yields this bigger graph:
6259 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6261 At the bottom of the graph, we see all the implicit inputs of
6262 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6264 Now, note that the dependencies of these implicit inputs---that is, the
6265 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6266 here, for conciseness.
6269 Similar to @code{bag-emerged}, but this time including all the bootstrap
6272 @item bag-with-origins
6273 Similar to @code{bag}, but also showing origins and their dependencies.
6276 This is the most detailed representation: It shows the DAG of
6277 derivations (@pxref{Derivations}) and plain store items. Compared to
6278 the above representation, many additional nodes are visible, including
6279 build scripts, patches, Guile modules, etc.
6281 For this type of graph, it is also possible to pass a @file{.drv} file
6282 name instead of a package name, as in:
6285 guix graph -t derivation `guix system build -d my-config.scm`
6289 All the types above correspond to @emph{build-time dependencies}. The
6290 following graph type represents the @emph{run-time dependencies}:
6294 This is the graph of @dfn{references} of a package output, as returned
6295 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6297 If the given package output is not available in the store, @command{guix
6298 graph} attempts to obtain dependency information from substitutes.
6300 Here you can also pass a store file name instead of a package name. For
6301 example, the command below produces the reference graph of your profile
6302 (which can be big!):
6305 guix graph -t references `readlink -f ~/.guix-profile`
6309 This is the graph of the @dfn{referrers} of a store item, as returned by
6310 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6312 This relies exclusively on local information from your store. For
6313 instance, let us suppose that the current Inkscape is available in 10
6314 profiles on your machine; @command{guix graph -t referrers inkscape}
6315 will show a graph rooted at Inkscape and with those 10 profiles linked
6318 It can help determine what is preventing a store item from being garbage
6323 The available options are the following:
6326 @item --type=@var{type}
6327 @itemx -t @var{type}
6328 Produce a graph output of @var{type}, where @var{type} must be one of
6329 the values listed above.
6332 List the supported graph types.
6334 @item --backend=@var{backend}
6335 @itemx -b @var{backend}
6336 Produce a graph using the selected @var{backend}.
6338 @item --list-backends
6339 List the supported graph backends.
6341 Currently, the available backends are Graphviz and d3.js.
6343 @item --expression=@var{expr}
6344 @itemx -e @var{expr}
6345 Consider the package @var{expr} evaluates to.
6347 This is useful to precisely refer to a package, as in this example:
6350 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6355 @node Invoking guix environment
6356 @section Invoking @command{guix environment}
6358 @cindex reproducible build environments
6359 @cindex development environments
6360 @cindex @command{guix environment}
6361 @cindex environment, package build environment
6362 The purpose of @command{guix environment} is to assist hackers in
6363 creating reproducible development environments without polluting their
6364 package profile. The @command{guix environment} tool takes one or more
6365 packages, builds all of their inputs, and creates a shell
6366 environment to use them.
6368 The general syntax is:
6371 guix environment @var{options} @var{package}@dots{}
6374 The following example spawns a new shell set up for the development of
6378 guix environment guile
6381 If the needed dependencies are not built yet, @command{guix environment}
6382 automatically builds them. The environment of the new shell is an augmented
6383 version of the environment that @command{guix environment} was run in.
6384 It contains the necessary search paths for building the given package
6385 added to the existing environment variables. To create a ``pure''
6386 environment, in which the original environment variables have been unset,
6387 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6388 environment variables such as @code{PATH} in their @file{~/.bashrc}
6389 file. As a consequence, when @code{guix environment} launches it, Bash
6390 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6391 environment variables. It is an error to define such environment
6392 variables in @file{.bashrc}; instead, they should be defined in
6393 @file{.bash_profile}, which is sourced only by log-in shells.
6394 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6395 details on Bash start-up files.}.
6397 @vindex GUIX_ENVIRONMENT
6398 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6399 variable in the shell it spawns; its value is the file name of the
6400 profile of this environment. This allows users to, say, define a
6401 specific prompt for development environments in their @file{.bashrc}
6402 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6405 if [ -n "$GUIX_ENVIRONMENT" ]
6407 export PS1="\u@@\h \w [dev]\$ "
6412 ... or to browse the profile:
6415 $ ls "$GUIX_ENVIRONMENT/bin"
6418 Additionally, more than one package may be specified, in which case the
6419 union of the inputs for the given packages are used. For example, the
6420 command below spawns a shell where all of the dependencies of both Guile
6421 and Emacs are available:
6424 guix environment guile emacs
6427 Sometimes an interactive shell session is not desired. An arbitrary
6428 command may be invoked by placing the @code{--} token to separate the
6429 command from the rest of the arguments:
6432 guix environment guile -- make -j4
6435 In other situations, it is more convenient to specify the list of
6436 packages needed in the environment. For example, the following command
6437 runs @command{python} from an environment containing Python@tie{}2.7 and
6441 guix environment --ad-hoc python2-numpy python-2.7 -- python
6444 Furthermore, one might want the dependencies of a package and also some
6445 additional packages that are not build-time or runtime dependencies, but
6446 are useful when developing nonetheless. Because of this, the
6447 @code{--ad-hoc} flag is positional. Packages appearing before
6448 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6449 added to the environment. Packages appearing after are interpreted as
6450 packages that will be added to the environment directly. For example,
6451 the following command creates a Guix development environment that
6452 additionally includes Git and strace:
6455 guix environment guix --ad-hoc git strace
6458 Sometimes it is desirable to isolate the environment as much as
6459 possible, for maximal purity and reproducibility. In particular, when
6460 using Guix on a host distro that is not GuixSD, it is desirable to
6461 prevent access to @file{/usr/bin} and other system-wide resources from
6462 the development environment. For example, the following command spawns
6463 a Guile REPL in a ``container'' where only the store and the current
6464 working directory are mounted:
6467 guix environment --ad-hoc --container guile -- guile
6471 The @code{--container} option requires Linux-libre 3.19 or newer.
6474 The available options are summarized below.
6477 @item --root=@var{file}
6478 @itemx -r @var{file}
6479 @cindex persistent environment
6480 @cindex garbage collector root, for environments
6481 Make @var{file} a symlink to the profile for this environment, and
6482 register it as a garbage collector root.
6484 This is useful if you want to protect your environment from garbage
6485 collection, to make it ``persistent''.
6487 When this option is omitted, the environment is protected from garbage
6488 collection only for the duration of the @command{guix environment}
6489 session. This means that next time you recreate the same environment,
6490 you could have to rebuild or re-download packages.
6492 @item --expression=@var{expr}
6493 @itemx -e @var{expr}
6494 Create an environment for the package or list of packages that
6495 @var{expr} evaluates to.
6497 For example, running:
6500 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6503 starts a shell with the environment for this specific variant of the
6509 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6512 starts a shell with all the GuixSD base packages available.
6514 The above commands only use the default output of the given packages.
6515 To select other outputs, two element tuples can be specified:
6518 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6521 @item --load=@var{file}
6522 @itemx -l @var{file}
6523 Create an environment for the package or list of packages that the code
6524 within @var{file} evaluates to.
6526 As an example, @var{file} might contain a definition like this
6527 (@pxref{Defining Packages}):
6530 @verbatiminclude environment-gdb.scm
6534 Include all specified packages in the resulting environment, as if an
6535 @i{ad hoc} package were defined with them as inputs. This option is
6536 useful for quickly creating an environment without having to write a
6537 package expression to contain the desired inputs.
6539 For instance, the command:
6542 guix environment --ad-hoc guile guile-sdl -- guile
6545 runs @command{guile} in an environment where Guile and Guile-SDL are
6548 Note that this example implicitly asks for the default output of
6549 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6550 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6551 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6553 This option may be composed with the default behavior of @command{guix
6554 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6555 as packages whose dependencies will be added to the environment, the
6556 default behavior. Packages appearing after are interpreted as packages
6557 that will be added to the environment directly.
6560 Unset existing environment variables when building the new environment.
6561 This has the effect of creating an environment in which search paths
6562 only contain package inputs.
6564 @item --search-paths
6565 Display the environment variable definitions that make up the
6568 @item --system=@var{system}
6569 @itemx -s @var{system}
6570 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6575 Run @var{command} within an isolated container. The current working
6576 directory outside the container is mapped inside the container.
6577 Additionally, a dummy home directory is created that matches the current
6578 user's home directory, and @file{/etc/passwd} is configured accordingly.
6579 The spawned process runs as the current user outside the container, but
6580 has root privileges in the context of the container.
6584 For containers, share the network namespace with the host system.
6585 Containers created without this flag only have access to the loopback
6588 @item --expose=@var{source}[=@var{target}]
6589 For containers, expose the file system @var{source} from the host system
6590 as the read-only file system @var{target} within the container. If
6591 @var{target} is not specified, @var{source} is used as the target mount
6592 point in the container.
6594 The example below spawns a Guile REPL in a container in which the user's
6595 home directory is accessible read-only via the @file{/exchange}
6599 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6602 @item --share=@var{source}[=@var{target}]
6603 For containers, share the file system @var{source} from the host system
6604 as the writable file system @var{target} within the container. If
6605 @var{target} is not specified, @var{source} is used as the target mount
6606 point in the container.
6608 The example below spawns a Guile REPL in a container in which the user's
6609 home directory is accessible for both reading and writing via the
6610 @file{/exchange} directory:
6613 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6617 @command{guix environment}
6618 also supports all of the common build options that @command{guix
6619 build} supports (@pxref{Common Build Options}).
6622 @node Invoking guix publish
6623 @section Invoking @command{guix publish}
6625 @cindex @command{guix publish}
6626 The purpose of @command{guix publish} is to enable users to easily share
6627 their store with others, who can then use it as a substitute server
6628 (@pxref{Substitutes}).
6630 When @command{guix publish} runs, it spawns an HTTP server which allows
6631 anyone with network access to obtain substitutes from it. This means
6632 that any machine running Guix can also act as if it were a build farm,
6633 since the HTTP interface is compatible with Hydra, the software behind
6634 the @code{hydra.gnu.org} build farm.
6636 For security, each substitute is signed, allowing recipients to check
6637 their authenticity and integrity (@pxref{Substitutes}). Because
6638 @command{guix publish} uses the signing key of the system, which is only
6639 readable by the system administrator, it must be started as root; the
6640 @code{--user} option makes it drop root privileges early on.
6642 The signing key pair must be generated before @command{guix publish} is
6643 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6646 The general syntax is:
6649 guix publish @var{options}@dots{}
6652 Running @command{guix publish} without any additional arguments will
6653 spawn an HTTP server on port 8080:
6659 Once a publishing server has been authorized (@pxref{Invoking guix
6660 archive}), the daemon may download substitutes from it:
6663 guix-daemon --substitute-urls=http://example.org:8080
6666 By default, @command{guix publish} compresses archives on the fly as it
6667 serves them. This ``on-the-fly'' mode is convenient in that it requires
6668 no setup and is immediately available. However, when serving lots of
6669 clients, we recommend using the @option{--cache} option, which enables
6670 caching of the archives before they are sent to clients---see below for
6673 As a bonus, @command{guix publish} also serves as a content-addressed
6674 mirror for source files referenced in @code{origin} records
6675 (@pxref{origin Reference}). For instance, assuming @command{guix
6676 publish} is running on @code{example.org}, the following URL returns the
6677 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6678 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6681 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6684 Obviously, these URLs only work for files that are in the store; in
6685 other cases, they return 404 (``Not Found'').
6687 The following options are available:
6690 @item --port=@var{port}
6691 @itemx -p @var{port}
6692 Listen for HTTP requests on @var{port}.
6694 @item --listen=@var{host}
6695 Listen on the network interface for @var{host}. The default is to
6696 accept connections from any interface.
6698 @item --user=@var{user}
6699 @itemx -u @var{user}
6700 Change privileges to @var{user} as soon as possible---i.e., once the
6701 server socket is open and the signing key has been read.
6703 @item --compression[=@var{level}]
6704 @itemx -C [@var{level}]
6705 Compress data using the given @var{level}. When @var{level} is zero,
6706 disable compression. The range 1 to 9 corresponds to different gzip
6707 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6710 Unless @option{--cache} is used, compression occurs on the fly and
6711 the compressed streams are not
6712 cached. Thus, to reduce load on the machine that runs @command{guix
6713 publish}, it may be a good idea to choose a low compression level, to
6714 run @command{guix publish} behind a caching proxy, or to use
6715 @option{--cache}. Using @option{--cache} has the advantage that it
6716 allows @command{guix publish} to add @code{Content-Length} HTTP header
6719 @item --cache=@var{directory}
6720 @itemx -c @var{directory}
6721 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6722 and only serve archives that are in cache.
6724 When this option is omitted, archives and meta-data are created
6725 on-the-fly. This can reduce the available bandwidth, especially when
6726 compression is enabled, since this may become CPU-bound. Another
6727 drawback of the default mode is that the length of archives is not known
6728 in advance, so @command{guix publish} does not add a
6729 @code{Content-Length} HTTP header to its responses, which in turn
6730 prevents clients from knowing the amount of data being downloaded.
6732 Conversely, when @option{--cache} is used, the first request for a store
6733 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6734 background process to @dfn{bake} the archive---computing its
6735 @code{.narinfo} and compressing the archive, if needed. Once the
6736 archive is cached in @var{directory}, subsequent requests succeed and
6737 are served directly from the cache, which guarantees that clients get
6738 the best possible bandwidth.
6740 The ``baking'' process is performed by worker threads. By default, one
6741 thread per CPU core is created, but this can be customized. See
6742 @option{--workers} below.
6744 When @option{--ttl} is used, cached entries are automatically deleted
6745 when they have expired.
6747 @item --workers=@var{N}
6748 When @option{--cache} is used, request the allocation of @var{N} worker
6749 threads to ``bake'' archives.
6751 @item --ttl=@var{ttl}
6752 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6753 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6754 days, @code{1m} means 1 month, and so on.
6756 This allows the user's Guix to keep substitute information in cache for
6757 @var{ttl}. However, note that @code{guix publish} does not itself
6758 guarantee that the store items it provides will indeed remain available
6759 for as long as @var{ttl}.
6761 Additionally, when @option{--cache} is used, cached entries that have
6762 not been accessed for @var{ttl} may be deleted.
6764 @item --nar-path=@var{path}
6765 Use @var{path} as the prefix for the URLs of ``nar'' files
6766 (@pxref{Invoking guix archive, normalized archives}).
6768 By default, nars are served at a URL such as
6769 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6770 change the @code{/nar} part to @var{path}.
6772 @item --public-key=@var{file}
6773 @itemx --private-key=@var{file}
6774 Use the specific @var{file}s as the public/private key pair used to sign
6775 the store items being published.
6777 The files must correspond to the same key pair (the private key is used
6778 for signing and the public key is merely advertised in the signature
6779 metadata). They must contain keys in the canonical s-expression format
6780 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6781 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6782 @file{/etc/guix/signing-key.sec} are used.
6784 @item --repl[=@var{port}]
6785 @itemx -r [@var{port}]
6786 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6787 Reference Manual}) on @var{port} (37146 by default). This is used
6788 primarily for debugging a running @command{guix publish} server.
6791 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6792 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6793 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6794 @code{guix-publish-service-type}}).
6796 If you are instead running Guix on a ``foreign distro'', follow these
6801 If your host distro uses the systemd init system:
6804 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6805 /etc/systemd/system/
6806 # systemctl start guix-publish && systemctl enable guix-publish
6810 If your host distro uses the Upstart init system:
6813 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6814 # start guix-publish
6818 Otherwise, proceed similarly with your distro's init system.
6821 @node Invoking guix challenge
6822 @section Invoking @command{guix challenge}
6824 @cindex reproducible builds
6825 @cindex verifiable builds
6826 @cindex @command{guix challenge}
6828 Do the binaries provided by this server really correspond to the source
6829 code it claims to build? Is a package build process deterministic?
6830 These are the questions the @command{guix challenge} command attempts to
6833 The former is obviously an important question: Before using a substitute
6834 server (@pxref{Substitutes}), one had better @emph{verify} that it
6835 provides the right binaries, and thus @emph{challenge} it. The latter
6836 is what enables the former: If package builds are deterministic, then
6837 independent builds of the package should yield the exact same result,
6838 bit for bit; if a server provides a binary different from the one
6839 obtained locally, it may be either corrupt or malicious.
6841 We know that the hash that shows up in @file{/gnu/store} file names is
6842 the hash of all the inputs of the process that built the file or
6843 directory---compilers, libraries, build scripts,
6844 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6845 one store file name should map to exactly one build output.
6846 @command{guix challenge} checks whether there is, indeed, a single
6847 mapping by comparing the build outputs of several independent builds of
6848 any given store item.
6850 The command output looks like this:
6853 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6854 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6855 updating list of substitutes from 'https://guix.example.org'... 100.0%
6856 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6857 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6858 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6859 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6860 /gnu/store/@dots{}-git-2.5.0 contents differ:
6861 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6862 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6863 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6864 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6865 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6866 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6867 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6871 In this example, @command{guix challenge} first scans the store to
6872 determine the set of locally-built derivations---as opposed to store
6873 items that were downloaded from a substitute server---and then queries
6874 all the substitute servers. It then reports those store items for which
6875 the servers obtained a result different from the local build.
6877 @cindex non-determinism, in package builds
6878 As an example, @code{guix.example.org} always gets a different answer.
6879 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6880 case of Git. This might indicate that the build process of Git is
6881 non-deterministic, meaning that its output varies as a function of
6882 various things that Guix does not fully control, in spite of building
6883 packages in isolated environments (@pxref{Features}). Most common
6884 sources of non-determinism include the addition of timestamps in build
6885 results, the inclusion of random numbers, and directory listings sorted
6886 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6889 To find out what is wrong with this Git binary, we can do something along
6890 these lines (@pxref{Invoking guix archive}):
6893 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6894 | guix archive -x /tmp/git
6895 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6898 This command shows the difference between the files resulting from the
6899 local build, and the files resulting from the build on
6900 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6901 diffutils, Comparing and Merging Files}). The @command{diff} command
6902 works great for text files. When binary files differ, a better option
6903 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6904 visualize differences for all kinds of files.
6906 Once you have done that work, you can tell whether the differences are due
6907 to a non-deterministic build process or to a malicious server. We try
6908 hard to remove sources of non-determinism in packages to make it easier
6909 to verify substitutes, but of course, this is a process that
6910 involves not just Guix, but a large part of the free software community.
6911 In the meantime, @command{guix challenge} is one tool to help address
6914 If you are writing packages for Guix, you are encouraged to check
6915 whether @code{hydra.gnu.org} and other substitute servers obtain the
6916 same build result as you did with:
6919 $ guix challenge @var{package}
6923 where @var{package} is a package specification such as
6924 @code{guile@@2.0} or @code{glibc:debug}.
6926 The general syntax is:
6929 guix challenge @var{options} [@var{packages}@dots{}]
6932 When a difference is found between the hash of a locally-built item and
6933 that of a server-provided substitute, or among substitutes provided by
6934 different servers, the command displays it as in the example above and
6935 its exit code is 2 (other non-zero exit codes denote other kinds of
6938 The one option that matters is:
6942 @item --substitute-urls=@var{urls}
6943 Consider @var{urls} the whitespace-separated list of substitute source
6948 Show details about matches (identical contents) in addition to
6949 information about mismatches.
6953 @node Invoking guix copy
6954 @section Invoking @command{guix copy}
6956 @cindex copy, of store items, over SSH
6957 @cindex SSH, copy of store items
6958 @cindex sharing store items across machines
6959 @cindex transferring store items across machines
6960 The @command{guix copy} command copies items from the store of one
6961 machine to that of another machine over a secure shell (SSH)
6962 connection@footnote{This command is available only when Guile-SSH was
6963 found. @xref{Requirements}, for details.}. For example, the following
6964 command copies the @code{coreutils} package, the user's profile, and all
6965 their dependencies over to @var{host}, logged in as @var{user}:
6968 guix copy --to=@var{user}@@@var{host} \
6969 coreutils `readlink -f ~/.guix-profile`
6972 If some of the items to be copied are already present on @var{host},
6973 they are not actually sent.
6975 The command below retrieves @code{libreoffice} and @code{gimp} from
6976 @var{host}, assuming they are available there:
6979 guix copy --from=@var{host} libreoffice gimp
6982 The SSH connection is established using the Guile-SSH client, which is
6983 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6984 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6986 The key used to sign items that are sent must be accepted by the remote
6987 machine. Likewise, the key used by the remote machine to sign items you
6988 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6989 own daemon. @xref{Invoking guix archive}, for more information about
6990 store item authentication.
6992 The general syntax is:
6995 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6998 You must always specify one of the following options:
7001 @item --to=@var{spec}
7002 @itemx --from=@var{spec}
7003 Specify the host to send to or receive from. @var{spec} must be an SSH
7004 spec such as @code{example.org}, @code{charlie@@example.org}, or
7005 @code{charlie@@example.org:2222}.
7008 The @var{items} can be either package names, such as @code{gimp}, or
7009 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7011 When specifying the name of a package to send, it is first built if
7012 needed, unless @option{--dry-run} was specified. Common build options
7013 are supported (@pxref{Common Build Options}).
7016 @node Invoking guix container
7017 @section Invoking @command{guix container}
7019 @cindex @command{guix container}
7021 As of version @value{VERSION}, this tool is experimental. The interface
7022 is subject to radical change in the future.
7025 The purpose of @command{guix container} is to manipulate processes
7026 running within an isolated environment, commonly known as a
7027 ``container'', typically created by the @command{guix environment}
7028 (@pxref{Invoking guix environment}) and @command{guix system container}
7029 (@pxref{Invoking guix system}) commands.
7031 The general syntax is:
7034 guix container @var{action} @var{options}@dots{}
7037 @var{action} specifies the operation to perform with a container, and
7038 @var{options} specifies the context-specific arguments for the action.
7040 The following actions are available:
7044 Execute a command within the context of a running container.
7049 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7052 @var{pid} specifies the process ID of the running container.
7053 @var{program} specifies an executable file name within the root file
7054 system of the container. @var{arguments} are the additional options that
7055 will be passed to @var{program}.
7057 The following command launches an interactive login shell inside a
7058 GuixSD container, started by @command{guix system container}, and whose
7062 guix container exec 9001 /run/current-system/profile/bin/bash --login
7065 Note that the @var{pid} cannot be the parent process of a container. It
7066 must be PID 1 of the container or one of its child processes.
7070 @c *********************************************************************
7071 @node GNU Distribution
7072 @chapter GNU Distribution
7074 @cindex Guix System Distribution
7076 Guix comes with a distribution of the GNU system consisting entirely of
7077 free software@footnote{The term ``free'' here refers to the
7078 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7079 users of that software}.}. The
7080 distribution can be installed on its own (@pxref{System Installation}),
7081 but it is also possible to install Guix as a package manager on top of
7082 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7083 between the two, we refer to the standalone distribution as the Guix
7084 System Distribution, or GuixSD.
7086 The distribution provides core GNU packages such as GNU libc, GCC, and
7087 Binutils, as well as many GNU and non-GNU applications. The complete
7088 list of available packages can be browsed
7089 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7090 running @command{guix package} (@pxref{Invoking guix package}):
7093 guix package --list-available
7096 Our goal is to provide a practical 100% free software distribution of
7097 Linux-based and other variants of GNU, with a focus on the promotion and
7098 tight integration of GNU components, and an emphasis on programs and
7099 tools that help users exert that freedom.
7101 Packages are currently available on the following platforms:
7106 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7109 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7112 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7113 using the EABI hard-float application binary interface (ABI),
7114 and Linux-Libre kernel.
7117 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7118 currently in an experimental stage, with limited support.
7119 @xref{Contributing}, for how to help!
7121 @item mips64el-linux
7122 little-endian 64-bit MIPS processors, specifically the Loongson series,
7123 n32 ABI, and Linux-Libre kernel.
7127 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7130 For information on porting to other architectures or kernels,
7134 * System Installation:: Installing the whole operating system.
7135 * System Configuration:: Configuring the operating system.
7136 * Documentation:: Browsing software user manuals.
7137 * Installing Debugging Files:: Feeding the debugger.
7138 * Security Updates:: Deploying security fixes quickly.
7139 * Package Modules:: Packages from the programmer's viewpoint.
7140 * Packaging Guidelines:: Growing the distribution.
7141 * Bootstrapping:: GNU/Linux built from scratch.
7142 * Porting:: Targeting another platform or kernel.
7145 Building this distribution is a cooperative effort, and you are invited
7146 to join! @xref{Contributing}, for information about how you can help.
7148 @node System Installation
7149 @section System Installation
7151 @cindex installing GuixSD
7152 @cindex Guix System Distribution
7153 This section explains how to install the Guix System Distribution (GuixSD)
7154 on a machine. The Guix package manager can
7155 also be installed on top of a running GNU/Linux system,
7156 @pxref{Installation}.
7160 @c This paragraph is for people reading this from tty2 of the
7161 @c installation image.
7162 You are reading this documentation with an Info reader. For details on
7163 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7164 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7165 Info}. Hit @kbd{l} afterwards to come back here.
7167 Alternately, run @command{info info} in another tty to keep the manual
7173 * Limitations:: What you can expect.
7174 * Hardware Considerations:: Supported hardware.
7175 * USB Stick Installation:: Preparing the installation medium.
7176 * Preparing for Installation:: Networking, partitioning, etc.
7177 * Proceeding with the Installation:: The real thing.
7178 * Installing GuixSD in a VM:: GuixSD playground.
7179 * Building the Installation Image:: How this comes to be.
7183 @subsection Limitations
7185 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7186 not production-ready. It may contain bugs and lack important
7187 features. Thus, if you are looking for a stable production system that
7188 respects your freedom as a computer user, a good solution at this point
7189 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7190 the more established GNU/Linux distributions}. We hope you can soon switch
7191 to the GuixSD without fear, of course. In the meantime, you can
7192 also keep using your distribution and try out the package manager on top
7193 of it (@pxref{Installation}).
7195 Before you proceed with the installation, be aware of the following
7196 noteworthy limitations applicable to version @value{VERSION}:
7200 The installation process does not include a graphical user interface and
7201 requires familiarity with GNU/Linux (see the following subsections to
7202 get a feel of what that means.)
7205 Support for the Logical Volume Manager (LVM) is missing.
7208 More and more system services are provided (@pxref{Services}), but some
7212 More than 5,300 packages are available, but you may
7213 occasionally find that a useful package is missing.
7216 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7217 as well as a number of X11 window managers. However, some graphical
7218 applications may be missing, as well as KDE.
7221 You have been warned! But more than a disclaimer, this is an invitation
7222 to report issues (and success stories!), and to join us in improving it.
7223 @xref{Contributing}, for more info.
7226 @node Hardware Considerations
7227 @subsection Hardware Considerations
7229 @cindex hardware support on GuixSD
7230 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7231 builds around the kernel Linux-libre, which means that only hardware for
7232 which free software drivers and firmware exist is supported. Nowadays,
7233 a wide range of off-the-shelf hardware is supported on
7234 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7235 Ethernet controllers. Unfortunately, there are still areas where
7236 hardware vendors deny users control over their own computing, and such
7237 hardware is not supported on GuixSD.
7239 @cindex WiFi, hardware support
7240 One of the main areas where free drivers or firmware are lacking is WiFi
7241 devices. WiFi devices known to work include those using Atheros chips
7242 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7243 driver, and those using Broadcom/AirForce chips (BCM43xx with
7244 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7245 Linux-libre driver. Free firmware exists for both and is available
7246 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7247 (@pxref{operating-system Reference, @code{firmware}}).
7249 @cindex RYF, Respects Your Freedom
7250 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7251 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7252 certification program for hardware products that respect your freedom
7253 and your privacy and ensure that you have control over your device. We
7254 encourage you to check the list of RYF-certified devices.
7256 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7257 web site. It contains a catalog of hardware devices with information
7258 about their support in GNU/Linux.
7261 @node USB Stick Installation
7262 @subsection USB Stick Installation
7264 An installation image for USB sticks can be downloaded from
7265 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7266 where @var{system} is one of:
7270 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7273 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7276 @c start duplication of authentication part from ``Binary Installation''
7277 Make sure to download the associated @file{.sig} file and to verify the
7278 authenticity of the image against it, along these lines:
7281 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7282 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7285 If that command fails because you do not have the required public key,
7286 then run this command to import it:
7289 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7293 and rerun the @code{gpg --verify} command.
7296 This image contains a single partition with the tools necessary for an
7297 installation. It is meant to be copied @emph{as is} to a large-enough
7300 To copy the image to a USB stick, follow these steps:
7304 Decompress the image using the @command{xz} command:
7307 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7311 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7312 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7313 copy the image with:
7316 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7320 Access to @file{/dev/sdX} usually requires root privileges.
7323 Once this is done, you should be able to reboot the system and boot from
7324 the USB stick. The latter usually requires you to get in the BIOS' boot
7325 menu, where you can choose to boot from the USB stick.
7327 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7328 GuixSD in a virtual machine (VM).
7330 @node Preparing for Installation
7331 @subsection Preparing for Installation
7333 Once you have successfully booted the image on the USB stick, you should
7334 end up with a root prompt. Several console TTYs are configured and can
7335 be used to run commands as root. TTY2 shows this documentation,
7336 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7337 Stand-alone GNU Info}). The installation system runs the GPM mouse
7338 daemon, which allows you to select text with the left mouse button and
7339 to paste it with the middle button.
7342 Installation requires access to the Internet so that any missing
7343 dependencies of your system configuration can be downloaded. See the
7344 ``Networking'' section below.
7347 The installation system includes many common tools needed for this task.
7348 But it is also a full-blown GuixSD system, which means that you can
7349 install additional packages, should you need it, using @command{guix
7350 package} (@pxref{Invoking guix package}).
7352 @subsubsection Keyboard Layout
7354 @cindex keyboard layout
7355 The installation image uses the US qwerty keyboard layout. If you want
7356 to change it, you can use the @command{loadkeys} command. For example,
7357 the following command selects the Dvorak keyboard layout:
7363 See the files under @file{/run/current-system/profile/share/keymaps} for
7364 a list of available keyboard layouts. Run @command{man loadkeys} for
7367 @subsubsection Networking
7369 Run the following command see what your network interfaces are called:
7376 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7382 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7383 Wired interfaces have a name starting with @samp{e}; for example, the
7384 interface corresponding to the first on-board Ethernet controller is
7385 called @samp{eno1}. Wireless interfaces have a name starting with
7386 @samp{w}, like @samp{w1p2s0}.
7389 @item Wired connection
7390 To configure a wired network run the following command, substituting
7391 @var{interface} with the name of the wired interface you want to use.
7394 ifconfig @var{interface} up
7397 @item Wireless connection
7400 To configure wireless networking, you can create a configuration file
7401 for the @command{wpa_supplicant} configuration tool (its location is not
7402 important) using one of the available text editors such as
7406 zile wpa_supplicant.conf
7409 As an example, the following stanza can go to this file and will work
7410 for many wireless networks, provided you give the actual SSID and
7411 passphrase for the network you are connecting to:
7415 ssid="@var{my-ssid}"
7417 psk="the network's secret passphrase"
7421 Start the wireless service and run it in the background with the
7422 following command (substitute @var{interface} with the name of the
7423 network interface you want to use):
7426 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7429 Run @command{man wpa_supplicant} for more information.
7433 At this point, you need to acquire an IP address. On a network where IP
7434 addresses are automatically assigned @i{via} DHCP, you can run:
7437 dhclient -v @var{interface}
7440 Try to ping a server to see if networking is up and running:
7446 Setting up network access is almost always a requirement because the
7447 image does not contain all the software and tools that may be needed.
7449 @subsubsection Disk Partitioning
7451 Unless this has already been done, the next step is to partition, and
7452 then format the target partition(s).
7454 The installation image includes several partitioning tools, including
7455 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7456 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7457 the partition layout you want:
7463 If your disk uses the GUID Partition Table (GPT) format and you plan to
7464 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7465 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7468 Once you are done partitioning the target hard disk drive, you have to
7469 create a file system on the relevant partition(s)@footnote{Currently
7470 GuixSD only supports ext4 and btrfs file systems. In particular, code
7471 that reads partition UUIDs and labels only works for these file system
7474 Preferably, assign partitions a label so that you can easily and
7475 reliably refer to them in @code{file-system} declarations (@pxref{File
7476 Systems}). This is typically done using the @code{-L} option of
7477 @command{mkfs.ext4} and related commands. So, assuming the target root
7478 partition lives at @file{/dev/sda1}, a file system with the label
7479 @code{my-root} can be created with:
7482 mkfs.ext4 -L my-root /dev/sda1
7485 @cindex encrypted disk
7486 If you are instead planning to encrypt the root partition, you can use
7487 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7488 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7489 @code{man cryptsetup}} for more information.) Assuming you want to
7490 store the root partition on @file{/dev/sda1}, the command sequence would
7491 be along these lines:
7494 cryptsetup luksFormat /dev/sda1
7495 cryptsetup open --type luks /dev/sda1 my-partition
7496 mkfs.ext4 -L my-root /dev/mapper/my-partition
7499 Once that is done, mount the target root partition under @file{/mnt}
7500 with a command like (again, assuming @code{my-root} is the label of the
7504 mount LABEL=my-root /mnt
7507 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7508 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7509 sure to initialize them with @command{mkswap}. Assuming you have one
7510 swap partition on @file{/dev/sda2}, you would run:
7517 Alternatively, you may use a swap file. For example, assuming that in
7518 the new system you want to use the file @file{/swapfile} as a swap file,
7519 you would run@footnote{This example will work for many types of file
7520 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7521 btrfs), the required steps may be different. For details, see the
7522 manual pages for @command{mkswap} and @command{swapon}.}:
7525 # This is 10 GiB of swap space. Adjust "count" to change the size.
7526 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7527 # For security, make the file readable and writable only by root.
7528 chmod 600 /mnt/swapfile
7529 mkswap /mnt/swapfile
7530 swapon /mnt/swapfile
7533 Note that if you have encrypted the root partition and created a swap
7534 file in its file system as described above, then the encryption also
7535 protects the swap file, just like any other file in that file system.
7537 @node Proceeding with the Installation
7538 @subsection Proceeding with the Installation
7540 With the target partitions ready and the target root mounted on
7541 @file{/mnt}, we're ready to go. First, run:
7544 herd start cow-store /mnt
7547 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7548 during the installation phase are written to the target disk on @file{/mnt}
7549 rather than kept in memory. This is necessary because the first phase of
7550 the @command{guix system init} command (see below) entails downloads or
7551 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7553 Next, you have to edit a file and
7554 provide the declaration of the operating system to be installed. To
7555 that end, the installation system comes with three text editors: GNU nano
7556 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7557 nvi (a clone of the original BSD @command{vi} editor).
7558 We strongly recommend storing that file on the target root file system, say,
7559 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7560 configuration file once you have rebooted into the newly-installed system.
7562 @xref{Using the Configuration System}, for an overview of the
7563 configuration file. The example configurations discussed in that
7564 section are available under @file{/etc/configuration} in the
7565 installation image. Thus, to get started with a system configuration
7566 providing a graphical display server (a ``desktop'' system), you can run
7567 something along these lines:
7571 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7572 # zile /mnt/etc/config.scm
7575 You should pay attention to what your configuration file contains, and
7580 Make sure the @code{grub-configuration} form refers to the device you
7581 want to install GRUB on.
7584 Be sure that your partition labels match the value of their respective
7585 @code{device} fields in your @code{file-system} configuration, assuming
7586 your @code{file-system} configuration sets the value of @code{title} to
7590 If there are encrypted or RAID partitions, make sure to add a
7591 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7594 Once you are done preparing the configuration file, the new system must
7595 be initialized (remember that the target root file system is mounted
7599 guix system init /mnt/etc/config.scm /mnt
7603 This copies all the necessary files and installs GRUB on
7604 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7605 more information, @pxref{Invoking guix system}. This command may trigger
7606 downloads or builds of missing packages, which can take some time.
7608 Once that command has completed---and hopefully succeeded!---you can run
7609 @command{reboot} and boot into the new system. The @code{root} password
7610 in the new system is initially empty; other users' passwords need to be
7611 initialized by running the @command{passwd} command as @code{root},
7612 unless your configuration specifies otherwise
7613 (@pxref{user-account-password, user account passwords}).
7615 @cindex upgrading GuixSD
7616 From then on, you can update GuixSD whenever you want by running
7617 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7618 then running @command{guix system reconfigure} to build a new system
7619 generation with the latest packages and services (@pxref{Invoking guix
7620 system}). We recommend doing that regularly so that your system
7621 includes the latest security updates (@pxref{Security Updates}).
7623 Join us on @code{#guix} on the Freenode IRC network or on
7624 @file{guix-devel@@gnu.org} to share your experience---good or not so
7627 @node Installing GuixSD in a VM
7628 @subsection Installing GuixSD in a Virtual Machine
7630 @cindex virtual machine, GuixSD installation
7631 If you'd like to install GuixSD in a virtual machine (VM) rather than on
7632 your beloved machine, this section is for you.
7634 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7635 disk image, follow these steps:
7639 First, retrieve and decompress the GuixSD installation image as
7640 described previously (@pxref{USB Stick Installation}).
7643 Create a disk image that will hold the installed system. To make a
7644 qcow2-formatted disk image, use the @command{qemu-img} command:
7647 qemu-img create -f qcow2 guixsd.img 5G
7650 This will create a 5GB file.
7653 Boot the USB installation image in an VM:
7656 qemu-system-x86_64 -m 1024 -smp 1 \
7657 -net user -net nic,model=virtio -boot menu=on \
7658 -drive file=guixsd.img \
7659 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7662 In the VM console, quickly press the @kbd{F12} key to enter the boot
7663 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7667 You're now root in the VM, proceed with the installation process.
7668 @xref{Preparing for Installation}, and follow the instructions.
7671 Once installation is complete, you can boot the system that's on your
7672 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7675 @node Building the Installation Image
7676 @subsection Building the Installation Image
7678 @cindex installation image
7679 The installation image described above was built using the @command{guix
7680 system} command, specifically:
7682 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7684 guix system disk-image --image-size=1G gnu/system/install.scm
7687 Have a look at @file{gnu/system/install.scm} in the source tree,
7688 and see also @ref{Invoking guix system} for more information
7689 about the installation image.
7691 @node System Configuration
7692 @section System Configuration
7694 @cindex system configuration
7695 The Guix System Distribution supports a consistent whole-system configuration
7696 mechanism. By that we mean that all aspects of the global system
7697 configuration---such as the available system services, timezone and
7698 locale settings, user accounts---are declared in a single place. Such
7699 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7701 One of the advantages of putting all the system configuration under the
7702 control of Guix is that it supports transactional system upgrades, and
7703 makes it possible to roll back to a previous system instantiation,
7704 should something go wrong with the new one (@pxref{Features}). Another
7705 advantage is that it makes it easy to replicate the exact same configuration
7706 across different machines, or at different points in time, without
7707 having to resort to additional administration tools layered on top of
7708 the own tools of the system.
7709 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7711 This section describes this mechanism. First we focus on the system
7712 administrator's viewpoint---explaining how the system is configured and
7713 instantiated. Then we show how this mechanism can be extended, for
7714 instance to support new system services.
7717 * Using the Configuration System:: Customizing your GNU system.
7718 * operating-system Reference:: Detail of operating-system declarations.
7719 * File Systems:: Configuring file system mounts.
7720 * Mapped Devices:: Block device extra processing.
7721 * User Accounts:: Specifying user accounts.
7722 * Locales:: Language and cultural convention settings.
7723 * Services:: Specifying system services.
7724 * Setuid Programs:: Programs running with root privileges.
7725 * X.509 Certificates:: Authenticating HTTPS servers.
7726 * Name Service Switch:: Configuring libc's name service switch.
7727 * Initial RAM Disk:: Linux-Libre bootstrapping.
7728 * GRUB Configuration:: Configuring the boot loader.
7729 * Invoking guix system:: Instantiating a system configuration.
7730 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7731 * Defining Services:: Adding new service definitions.
7734 @node Using the Configuration System
7735 @subsection Using the Configuration System
7737 The operating system is configured by providing an
7738 @code{operating-system} declaration in a file that can then be passed to
7739 the @command{guix system} command (@pxref{Invoking guix system}). A
7740 simple setup, with the default system services, the default Linux-Libre
7741 kernel, initial RAM disk, and boot loader looks like this:
7743 @findex operating-system
7745 @include os-config-bare-bones.texi
7748 This example should be self-describing. Some of the fields defined
7749 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7750 Others, such as @code{packages} and @code{services}, can be omitted, in
7751 which case they get a default value.
7753 Below we discuss the effect of some of the most important fields
7754 (@pxref{operating-system Reference}, for details about all the available
7755 fields), and how to @dfn{instantiate} the operating system using
7756 @command{guix system}.
7758 @unnumberedsubsubsec Globally-Visible Packages
7760 @vindex %base-packages
7761 The @code{packages} field lists packages that will be globally visible
7762 on the system, for all user accounts---i.e., in every user's @code{PATH}
7763 environment variable---in addition to the per-user profiles
7764 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7765 provides all the tools one would expect for basic user and administrator
7766 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7767 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7768 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7769 packages admin)} module (@pxref{Package Modules}). The
7770 @code{(list package output)} syntax can be used to add a specific output
7774 (use-modules (gnu packages))
7775 (use-modules (gnu packages dns))
7779 (packages (cons (list bind "utils")
7783 @findex specification->package
7784 Referring to packages by variable name, like @var{tcpdump} above, has
7785 the advantage of being unambiguous; it also allows typos and such to be
7786 diagnosed right away as ``unbound variables''. The downside is that one
7787 needs to know which module defines which package, and to augment the
7788 @code{use-package-modules} line accordingly. To avoid that, one can use
7789 the @code{specification->package} procedure of the @code{(gnu packages)}
7790 module, which returns the best package for a given name or name and
7794 (use-modules (gnu packages))
7798 (packages (append (map specification->package
7799 '("tcpdump" "htop" "gnupg@@2.0"))
7803 @unnumberedsubsubsec System Services
7806 @vindex %base-services
7807 The @code{services} field lists @dfn{system services} to be made
7808 available when the system starts (@pxref{Services}).
7809 The @code{operating-system} declaration above specifies that, in
7810 addition to the basic services, we want the @command{lshd} secure shell
7811 daemon listening on port 2222 (@pxref{Networking Services,
7812 @code{lsh-service}}). Under the hood,
7813 @code{lsh-service} arranges so that @code{lshd} is started with the
7814 right command-line options, possibly with supporting configuration files
7815 generated as needed (@pxref{Defining Services}).
7817 @cindex customization, of services
7818 @findex modify-services
7819 Occasionally, instead of using the base services as is, you will want to
7820 customize them. To do this, use @code{modify-services} (@pxref{Service
7821 Reference, @code{modify-services}}) to modify the list.
7823 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7824 (the console log-in) in the @var{%base-services} list (@pxref{Base
7825 Services, @code{%base-services}}). To do that, you can write the
7826 following in your operating system declaration:
7829 (define %my-services
7830 ;; My very own list of services.
7831 (modify-services %base-services
7832 (guix-service-type config =>
7835 (use-substitutes? #f)
7836 (extra-options '("--gc-keep-derivations"))))
7837 (mingetty-service-type config =>
7838 (mingetty-configuration
7839 (inherit config)))))
7843 (services %my-services))
7846 This changes the configuration---i.e., the service parameters---of the
7847 @code{guix-service-type} instance, and that of all the
7848 @code{mingetty-service-type} instances in the @var{%base-services} list.
7849 Observe how this is accomplished: first, we arrange for the original
7850 configuration to be bound to the identifier @code{config} in the
7851 @var{body}, and then we write the @var{body} so that it evaluates to the
7852 desired configuration. In particular, notice how we use @code{inherit}
7853 to create a new configuration which has the same values as the old
7854 configuration, but with a few modifications.
7856 @cindex encrypted disk
7857 The configuration for a typical ``desktop'' usage, with an encrypted
7858 root partition, the X11 display
7859 server, GNOME and Xfce (users can choose which of these desktop
7860 environments to use at the log-in screen by pressing @kbd{F1}), network
7861 management, power management, and more, would look like this:
7864 @include os-config-desktop.texi
7867 A graphical environment with a choice of lightweight window managers
7868 instead of full-blown desktop environments would look like this:
7871 @include os-config-lightweight-desktop.texi
7874 @xref{Desktop Services}, for the exact list of services provided by
7875 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7876 information about the @code{nss-certs} package that is used here.
7878 Again, @var{%desktop-services} is just a list of service objects. If
7879 you want to remove services from there, you can do so using the
7880 procedures for list filtering (@pxref{SRFI-1 Filtering and
7881 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7882 following expression returns a list that contains all the services in
7883 @var{%desktop-services} minus the Avahi service:
7886 (remove (lambda (service)
7887 (eq? (service-kind service) avahi-service-type))
7891 @unnumberedsubsubsec Instantiating the System
7893 Assuming the @code{operating-system} declaration
7894 is stored in the @file{my-system-config.scm}
7895 file, the @command{guix system reconfigure my-system-config.scm} command
7896 instantiates that configuration, and makes it the default GRUB boot
7897 entry (@pxref{Invoking guix system}).
7899 The normal way to change the system configuration is by updating this
7900 file and re-running @command{guix system reconfigure}. One should never
7901 have to touch files in @file{/etc} or to run commands that modify the
7902 system state such as @command{useradd} or @command{grub-install}. In
7903 fact, you must avoid that since that would not only void your warranty
7904 but also prevent you from rolling back to previous versions of your
7905 system, should you ever need to.
7907 @cindex roll-back, of the operating system
7908 Speaking of roll-back, each time you run @command{guix system
7909 reconfigure}, a new @dfn{generation} of the system is created---without
7910 modifying or deleting previous generations. Old system generations get
7911 an entry in the GRUB boot menu, allowing you to boot them in case
7912 something went wrong with the latest generation. Reassuring, no? The
7913 @command{guix system list-generations} command lists the system
7914 generations available on disk. It is also possible to roll back the
7915 system via the commands @command{guix system roll-back} and
7916 @command{guix system switch-generation}.
7918 Although the command @command{guix system reconfigure} will not modify
7919 previous generations, must take care when the current generation is not
7920 the latest (e.g., after invoking @command{guix system roll-back}), since
7921 the operation might overwrite a later generation (@pxref{Invoking guix
7924 @unnumberedsubsubsec The Programming Interface
7926 At the Scheme level, the bulk of an @code{operating-system} declaration
7927 is instantiated with the following monadic procedure (@pxref{The Store
7930 @deffn {Monadic Procedure} operating-system-derivation os
7931 Return a derivation that builds @var{os}, an @code{operating-system}
7932 object (@pxref{Derivations}).
7934 The output of the derivation is a single directory that refers to all
7935 the packages, configuration files, and other supporting files needed to
7936 instantiate @var{os}.
7939 This procedure is provided by the @code{(gnu system)} module. Along
7940 with @code{(gnu services)} (@pxref{Services}), this module contains the
7941 guts of GuixSD. Make sure to visit it!
7944 @node operating-system Reference
7945 @subsection @code{operating-system} Reference
7947 This section summarizes all the options available in
7948 @code{operating-system} declarations (@pxref{Using the Configuration
7951 @deftp {Data Type} operating-system
7952 This is the data type representing an operating system configuration.
7953 By that, we mean all the global system configuration, not per-user
7954 configuration (@pxref{Using the Configuration System}).
7957 @item @code{kernel} (default: @var{linux-libre})
7958 The package object of the operating system kernel to use@footnote{Currently
7959 only the Linux-libre kernel is supported. In the future, it will be
7960 possible to use the GNU@tie{}Hurd.}.
7962 @item @code{kernel-arguments} (default: @code{'()})
7963 List of strings or gexps representing additional arguments to pass on
7964 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7966 @item @code{bootloader}
7967 The system bootloader configuration object. @xref{GRUB Configuration}.
7969 @item @code{initrd} (default: @code{base-initrd})
7971 @cindex initial RAM disk
7972 A two-argument monadic procedure that returns an initial RAM disk for
7973 the Linux kernel. @xref{Initial RAM Disk}.
7975 @item @code{firmware} (default: @var{%base-firmware})
7977 List of firmware packages loadable by the operating system kernel.
7979 The default includes firmware needed for Atheros- and Broadcom-based
7980 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
7981 respectively). @xref{Hardware Considerations}, for more info on
7984 @item @code{host-name}
7987 @item @code{hosts-file}
7989 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
7990 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
7991 Reference Manual}). The default is a file with entries for
7992 @code{localhost} and @var{host-name}.
7994 @item @code{mapped-devices} (default: @code{'()})
7995 A list of mapped devices. @xref{Mapped Devices}.
7997 @item @code{file-systems}
7998 A list of file systems. @xref{File Systems}.
8000 @item @code{swap-devices} (default: @code{'()})
8001 @cindex swap devices
8002 A list of strings identifying devices or files to be used for ``swap
8003 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8004 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8005 It is possible to specify a swap file in a file system on a mapped
8006 device, provided that the necessary device mapping and file system are
8007 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8009 @item @code{users} (default: @code{%base-user-accounts})
8010 @itemx @code{groups} (default: @var{%base-groups})
8011 List of user accounts and groups. @xref{User Accounts}.
8013 @item @code{skeletons} (default: @code{(default-skeletons)})
8014 A list target file name/file-like object tuples (@pxref{G-Expressions,
8015 file-like objects}). These are the skeleton files that will be added to
8016 the home directory of newly-created user accounts.
8018 For instance, a valid value may look like this:
8021 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8022 (".guile" ,(plain-file "guile"
8023 "(use-modules (ice-9 readline))
8024 (activate-readline)")))
8027 @item @code{issue} (default: @var{%default-issue})
8028 A string denoting the contents of the @file{/etc/issue} file, which is
8029 displayed when users log in on a text console.
8031 @item @code{packages} (default: @var{%base-packages})
8032 The set of packages installed in the global profile, which is accessible
8033 at @file{/run/current-system/profile}.
8035 The default set includes core utilities and it is good practice to
8036 install non-core utilities in user profiles (@pxref{Invoking guix
8039 @item @code{timezone}
8040 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8042 You can run the @command{tzselect} command to find out which timezone
8043 string corresponds to your region. Choosing an invalid timezone name
8044 causes @command{guix system} to fail.
8046 @item @code{locale} (default: @code{"en_US.utf8"})
8047 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8048 Library Reference Manual}). @xref{Locales}, for more information.
8050 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8051 The list of locale definitions to be compiled and that may be used at
8052 run time. @xref{Locales}.
8054 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8055 The list of GNU@tie{}libc packages whose locale data and tools are used
8056 to build the locale definitions. @xref{Locales}, for compatibility
8057 considerations that justify this option.
8059 @item @code{name-service-switch} (default: @var{%default-nss})
8060 Configuration of the libc name service switch (NSS)---a
8061 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8064 @item @code{services} (default: @var{%base-services})
8065 A list of service objects denoting system services. @xref{Services}.
8067 @item @code{pam-services} (default: @code{(base-pam-services)})
8069 @cindex pluggable authentication modules
8070 Linux @dfn{pluggable authentication module} (PAM) services.
8071 @c FIXME: Add xref to PAM services section.
8073 @item @code{setuid-programs} (default: @var{%setuid-programs})
8074 List of string-valued G-expressions denoting setuid programs.
8075 @xref{Setuid Programs}.
8077 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8078 @cindex sudoers file
8079 The contents of the @file{/etc/sudoers} file as a file-like object
8080 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8082 This file specifies which users can use the @command{sudo} command, what
8083 they are allowed to do, and what privileges they may gain. The default
8084 is that only @code{root} and members of the @code{wheel} group may use
8091 @subsection File Systems
8093 The list of file systems to be mounted is specified in the
8094 @code{file-systems} field of the operating system declaration
8095 (@pxref{Using the Configuration System}). Each file system is declared
8096 using the @code{file-system} form, like this:
8100 (mount-point "/home")
8101 (device "/dev/sda3")
8105 As usual, some of the fields are mandatory---those shown in the example
8106 above---while others can be omitted. These are described below.
8108 @deftp {Data Type} file-system
8109 Objects of this type represent file systems to be mounted. They
8110 contain the following members:
8114 This is a string specifying the type of the file system---e.g.,
8117 @item @code{mount-point}
8118 This designates the place where the file system is to be mounted.
8121 This names the ``source'' of the file system. By default it is the name
8122 of a node under @file{/dev}, but its meaning depends on the @code{title}
8123 field described below.
8125 @item @code{title} (default: @code{'device})
8126 This is a symbol that specifies how the @code{device} field is to be
8129 When it is the symbol @code{device}, then the @code{device} field is
8130 interpreted as a file name; when it is @code{label}, then @code{device}
8131 is interpreted as a partition label name; when it is @code{uuid},
8132 @code{device} is interpreted as a partition unique identifier (UUID).
8134 UUIDs may be converted from their string representation (as shown by the
8135 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8136 @code{uuid} form expects 16-byte UUIDs as defined in
8137 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8138 form of UUID used by the ext2 family of file systems and others, but it
8139 is different from ``UUIDs'' found in FAT file systems, for instance.},
8144 (mount-point "/home")
8147 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8150 The @code{label} and @code{uuid} options offer a way to refer to disk
8151 partitions without having to hard-code their actual device
8152 name@footnote{Note that, while it is tempting to use
8153 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8154 result, this is not recommended: These special device nodes are created
8155 by the udev daemon and may be unavailable at the time the device is
8158 However, when the source of a file system is a mapped device (@pxref{Mapped
8159 Devices}), its @code{device} field @emph{must} refer to the mapped
8160 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8161 @code{title} must be set to @code{'device}. This is required so that
8162 the system knows that mounting the file system depends on having the
8163 corresponding device mapping established.
8165 @item @code{flags} (default: @code{'()})
8166 This is a list of symbols denoting mount flags. Recognized flags
8167 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8168 access to special files), @code{no-suid} (ignore setuid and setgid
8169 bits), and @code{no-exec} (disallow program execution.)
8171 @item @code{options} (default: @code{#f})
8172 This is either @code{#f}, or a string denoting mount options.
8174 @item @code{mount?} (default: @code{#t})
8175 This value indicates whether to automatically mount the file system when
8176 the system is brought up. When set to @code{#f}, the file system gets
8177 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8178 is not automatically mounted.
8180 @item @code{needed-for-boot?} (default: @code{#f})
8181 This Boolean value indicates whether the file system is needed when
8182 booting. If that is true, then the file system is mounted when the
8183 initial RAM disk (initrd) is loaded. This is always the case, for
8184 instance, for the root file system.
8186 @item @code{check?} (default: @code{#t})
8187 This Boolean indicates whether the file system needs to be checked for
8188 errors before being mounted.
8190 @item @code{create-mount-point?} (default: @code{#f})
8191 When true, the mount point is created if it does not exist yet.
8193 @item @code{dependencies} (default: @code{'()})
8194 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8195 representing file systems that must be mounted or mapped devices that
8196 must be opened before (and unmounted or closed after) this one.
8198 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8199 a dependency of @file{/sys/fs/cgroup/cpu} and
8200 @file{/sys/fs/cgroup/memory}.
8202 Another example is a file system that depends on a mapped device, for
8203 example for an encrypted partition (@pxref{Mapped Devices}).
8207 The @code{(gnu system file-systems)} exports the following useful
8210 @defvr {Scheme Variable} %base-file-systems
8211 These are essential file systems that are required on normal systems,
8212 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8213 below.) Operating system declarations should always contain at least
8217 @defvr {Scheme Variable} %pseudo-terminal-file-system
8218 This is the file system to be mounted as @file{/dev/pts}. It supports
8219 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8220 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8221 Manual}). Pseudo-terminals are used by terminal emulators such as
8225 @defvr {Scheme Variable} %shared-memory-file-system
8226 This file system is mounted as @file{/dev/shm} and is used to support
8227 memory sharing across processes (@pxref{Memory-mapped I/O,
8228 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8231 @defvr {Scheme Variable} %immutable-store
8232 This file system performs a read-only ``bind mount'' of
8233 @file{/gnu/store}, making it read-only for all the users including
8234 @code{root}. This prevents against accidental modification by software
8235 running as @code{root} or by system administrators.
8237 The daemon itself is still able to write to the store: it remounts it
8238 read-write in its own ``name space.''
8241 @defvr {Scheme Variable} %binary-format-file-system
8242 The @code{binfmt_misc} file system, which allows handling of arbitrary
8243 executable file types to be delegated to user space. This requires the
8244 @code{binfmt.ko} kernel module to be loaded.
8247 @defvr {Scheme Variable} %fuse-control-file-system
8248 The @code{fusectl} file system, which allows unprivileged users to mount
8249 and unmount user-space FUSE file systems. This requires the
8250 @code{fuse.ko} kernel module to be loaded.
8253 @node Mapped Devices
8254 @subsection Mapped Devices
8256 @cindex device mapping
8257 @cindex mapped devices
8258 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8259 such as a hard disk partition, can be @dfn{mapped} into another device,
8260 usually in @code{/dev/mapper/},
8261 with additional processing over the data that flows through
8262 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8263 concept of a ``mapped device'' and that of a file system: both boil down
8264 to @emph{translating} input/output operations made on a file to
8265 operations on its backing store. Thus, the Hurd implements mapped
8266 devices, like file systems, using the generic @dfn{translator} mechanism
8267 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8268 typical example is encryption device mapping: all writes to the mapped
8269 device are encrypted, and all reads are deciphered, transparently.
8270 Guix extends this notion by considering any device or set of devices that
8271 are @dfn{transformed} in some way to create a new device; for instance,
8272 RAID devices are obtained by @dfn{assembling} several other devices, such
8273 as hard disks or partitions, into a new one that behaves as one partition.
8274 Other examples, not yet implemented, are LVM logical volumes.
8276 Mapped devices are declared using the @code{mapped-device} form,
8277 defined as follows; for examples, see below.
8279 @deftp {Data Type} mapped-device
8280 Objects of this type represent device mappings that will be made when
8281 the system boots up.
8285 This is either a string specifying the name of the block device to be mapped,
8286 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8287 need to be assembled for creating a new one.
8290 This string specifies the name of the resulting mapped device. For
8291 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8292 specifying @code{"my-partition"} leads to the creation of
8293 the @code{"/dev/mapper/my-partition"} device.
8294 For RAID devices of type @code{raid-device-mapping}, the full device name
8295 such as @code{"/dev/md0"} needs to be given.
8298 This must be a @code{mapped-device-kind} object, which specifies how
8299 @var{source} is mapped to @var{target}.
8303 @defvr {Scheme Variable} luks-device-mapping
8304 This defines LUKS block device encryption using the @command{cryptsetup}
8305 command from the package with the same name. It relies on the
8306 @code{dm-crypt} Linux kernel module.
8309 @defvr {Scheme Variable} raid-device-mapping
8310 This defines a RAID device, which is assembled using the @code{mdadm}
8311 command from the package with the same name. It requires a Linux kernel
8312 module for the appropriate RAID level to be loaded, such as @code{raid456}
8313 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8316 @cindex disk encryption
8318 The following example specifies a mapping from @file{/dev/sda3} to
8319 @file{/dev/mapper/home} using LUKS---the
8320 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8321 standard mechanism for disk encryption.
8322 The @file{/dev/mapper/home}
8323 device can then be used as the @code{device} of a @code{file-system}
8324 declaration (@pxref{File Systems}).
8328 (source "/dev/sda3")
8330 (type luks-device-mapping))
8333 Alternatively, to become independent of device numbering, one may obtain
8334 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8338 cryptsetup luksUUID /dev/sda3
8341 and use it as follows:
8345 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8347 (type luks-device-mapping))
8350 @cindex swap encryption
8351 It is also desirable to encrypt swap space, since swap space may contain
8352 sensitive data. One way to accomplish that is to use a swap file in a
8353 file system on a device mapped via LUKS encryption. In this way, the
8354 swap file is encrypted because the entire device is encrypted.
8355 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8357 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8358 may be declared as follows:
8362 (source (list "/dev/sda1" "/dev/sdb1"))
8364 (type raid-device-mapping))
8367 The @file{/dev/md0} device can then be used as the @code{device} of a
8368 @code{file-system} declaration (@pxref{File Systems}).
8369 Note that the RAID level need not be given; it is chosen during the
8370 initial creation and formatting of the RAID device and is determined
8371 automatically later.
8375 @subsection User Accounts
8379 @cindex user accounts
8380 User accounts and groups are entirely managed through the
8381 @code{operating-system} declaration. They are specified with the
8382 @code{user-account} and @code{user-group} forms:
8388 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8390 "video" ;video devices such as webcams
8391 "cdrom")) ;the good ol' CD-ROM
8392 (comment "Bob's sister")
8393 (home-directory "/home/alice"))
8396 When booting or upon completion of @command{guix system reconfigure},
8397 the system ensures that only the user accounts and groups specified in
8398 the @code{operating-system} declaration exist, and with the specified
8399 properties. Thus, account or group creations or modifications made by
8400 directly invoking commands such as @command{useradd} are lost upon
8401 reconfiguration or reboot. This ensures that the system remains exactly
8404 @deftp {Data Type} user-account
8405 Objects of this type represent user accounts. The following members may
8410 The name of the user account.
8414 This is the name (a string) or identifier (a number) of the user group
8415 this account belongs to.
8417 @item @code{supplementary-groups} (default: @code{'()})
8418 Optionally, this can be defined as a list of group names that this
8421 @item @code{uid} (default: @code{#f})
8422 This is the user ID for this account (a number), or @code{#f}. In the
8423 latter case, a number is automatically chosen by the system when the
8426 @item @code{comment} (default: @code{""})
8427 A comment about the account, such as the account owner's full name.
8429 @item @code{home-directory}
8430 This is the name of the home directory for the account.
8432 @item @code{create-home-directory?} (default: @code{#t})
8433 Indicates whether the home directory of this account should be created
8434 if it does not exist yet.
8436 @item @code{shell} (default: Bash)
8437 This is a G-expression denoting the file name of a program to be used as
8438 the shell (@pxref{G-Expressions}).
8440 @item @code{system?} (default: @code{#f})
8441 This Boolean value indicates whether the account is a ``system''
8442 account. System accounts are sometimes treated specially; for instance,
8443 graphical login managers do not list them.
8445 @anchor{user-account-password}
8446 @item @code{password} (default: @code{#f})
8447 You would normally leave this field to @code{#f}, initialize user
8448 passwords as @code{root} with the @command{passwd} command, and then let
8449 users change it with @command{passwd}. Passwords set with
8450 @command{passwd} are of course preserved across reboot and
8453 If you @emph{do} want to have a preset password for an account, then
8454 this field must contain the encrypted password, as a string.
8455 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8456 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8457 Manual}, for information on Guile's @code{crypt} procedure.
8463 User group declarations are even simpler:
8466 (user-group (name "students"))
8469 @deftp {Data Type} user-group
8470 This type is for, well, user groups. There are just a few fields:
8474 The name of the group.
8476 @item @code{id} (default: @code{#f})
8477 The group identifier (a number). If @code{#f}, a new number is
8478 automatically allocated when the group is created.
8480 @item @code{system?} (default: @code{#f})
8481 This Boolean value indicates whether the group is a ``system'' group.
8482 System groups have low numerical IDs.
8484 @item @code{password} (default: @code{#f})
8485 What, user groups can have a password? Well, apparently yes. Unless
8486 @code{#f}, this field specifies the password of the group.
8491 For convenience, a variable lists all the basic user groups one may
8494 @defvr {Scheme Variable} %base-groups
8495 This is the list of basic user groups that users and/or packages expect
8496 to be present on the system. This includes groups such as ``root'',
8497 ``wheel'', and ``users'', as well as groups used to control access to
8498 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8501 @defvr {Scheme Variable} %base-user-accounts
8502 This is the list of basic system accounts that programs may expect to
8503 find on a GNU/Linux system, such as the ``nobody'' account.
8505 Note that the ``root'' account is not included here. It is a
8506 special-case and is automatically added whether or not it is specified.
8513 A @dfn{locale} defines cultural conventions for a particular language
8514 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8515 Reference Manual}). Each locale has a name that typically has the form
8516 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8517 @code{fr_LU.utf8} designates the locale for the French language, with
8518 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8520 @cindex locale definition
8521 Usually, you will want to specify the default locale for the machine
8522 using the @code{locale} field of the @code{operating-system} declaration
8523 (@pxref{operating-system Reference, @code{locale}}).
8525 The selected locale is automatically added to the @dfn{locale
8526 definitions} known to the system if needed, with its codeset inferred
8527 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8528 @code{UTF-8} codeset. Additional locale definitions can be specified in
8529 the @code{locale-definitions} slot of @code{operating-system}---this is
8530 useful, for instance, if the codeset could not be inferred from the
8531 locale name. The default set of locale definitions includes some widely
8532 used locales, but not all the available locales, in order to save space.
8534 For instance, to add the North Frisian locale for Germany, the value of
8538 (cons (locale-definition
8539 (name "fy_DE.utf8") (source "fy_DE"))
8540 %default-locale-definitions)
8543 Likewise, to save space, one might want @code{locale-definitions} to
8544 list only the locales that are actually used, as in:
8547 (list (locale-definition
8548 (name "ja_JP.eucjp") (source "ja_JP")
8549 (charset "EUC-JP")))
8553 The compiled locale definitions are available at
8554 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8555 version, which is the default location where the GNU@tie{}libc provided
8556 by Guix looks for locale data. This can be overridden using the
8557 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8558 @code{LOCPATH} and locale packages}).
8560 The @code{locale-definition} form is provided by the @code{(gnu system
8561 locale)} module. Details are given below.
8563 @deftp {Data Type} locale-definition
8564 This is the data type of a locale definition.
8569 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8570 Reference Manual}, for more information on locale names.
8573 The name of the source for that locale. This is typically the
8574 @code{@var{language}_@var{territory}} part of the locale name.
8576 @item @code{charset} (default: @code{"UTF-8"})
8577 The ``character set'' or ``code set'' for that locale,
8578 @uref{http://www.iana.org/assignments/character-sets, as defined by
8584 @defvr {Scheme Variable} %default-locale-definitions
8585 A list of commonly used UTF-8 locales, used as the default
8586 value of the @code{locale-definitions} field of @code{operating-system}
8590 @cindex normalized codeset in locale names
8591 These locale definitions use the @dfn{normalized codeset} for the part
8592 that follows the dot in the name (@pxref{Using gettextized software,
8593 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8594 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8598 @subsubsection Locale Data Compatibility Considerations
8600 @cindex incompatibility, of locale data
8601 @code{operating-system} declarations provide a @code{locale-libcs} field
8602 to specify the GNU@tie{}libc packages that are used to compile locale
8603 declarations (@pxref{operating-system Reference}). ``Why would I
8604 care?'', you may ask. Well, it turns out that the binary format of
8605 locale data is occasionally incompatible from one libc version to
8608 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8609 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8610 For instance, a program linked against libc version 2.21 is unable to
8611 read locale data produced with libc 2.22; worse, that program
8612 @emph{aborts} instead of simply ignoring the incompatible locale
8613 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8614 the incompatible locale data, which is already an improvement.}.
8615 Similarly, a program linked against libc 2.22 can read most, but not
8616 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8617 data is incompatible); thus calls to @code{setlocale} may fail, but
8618 programs will not abort.
8620 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8621 choose whether and when to upgrade software in their profiles, and might
8622 be using a libc version different from the one the system administrator
8623 used to build the system-wide locale data.
8625 Fortunately, unprivileged users can also install their own locale data
8626 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8627 @code{GUIX_LOCPATH} and locale packages}).
8629 Still, it is best if the system-wide locale data at
8630 @file{/run/current-system/locale} is built for all the libc versions
8631 actually in use on the system, so that all the programs can access
8632 it---this is especially crucial on a multi-user system. To do that, the
8633 administrator can specify several libc packages in the
8634 @code{locale-libcs} field of @code{operating-system}:
8637 (use-package-modules base)
8641 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8644 This example would lead to a system containing locale definitions for
8645 both libc 2.21 and the current version of libc in
8646 @file{/run/current-system/locale}.
8650 @subsection Services
8652 @cindex system services
8653 An important part of preparing an @code{operating-system} declaration is
8654 listing @dfn{system services} and their configuration (@pxref{Using the
8655 Configuration System}). System services are typically daemons launched
8656 when the system boots, or other actions needed at that time---e.g.,
8657 configuring network access.
8659 GuixSD has a broad definition of ``service'' (@pxref{Service
8660 Composition}), but many services are managed by the GNU@tie{}Shepherd
8661 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8662 command allows you to list the available services, show their status,
8663 start and stop them, or do other specific operations (@pxref{Jump
8664 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8670 The above command, run as @code{root}, lists the currently defined
8671 services. The @command{herd doc} command shows a synopsis of the given
8676 Run libc's name service cache daemon (nscd).
8679 The @command{start}, @command{stop}, and @command{restart} sub-commands
8680 have the effect you would expect. For instance, the commands below stop
8681 the nscd service and restart the Xorg display server:
8685 Service nscd has been stopped.
8686 # herd restart xorg-server
8687 Service xorg-server has been stopped.
8688 Service xorg-server has been started.
8691 The following sections document the available services, starting with
8692 the core services, that may be used in an @code{operating-system}
8696 * Base Services:: Essential system services.
8697 * Scheduled Job Execution:: The mcron service.
8698 * Log Rotation:: The rottlog service.
8699 * Networking Services:: Network setup, SSH daemon, etc.
8700 * X Window:: Graphical display.
8701 * Printing Services:: Local and remote printer support.
8702 * Desktop Services:: D-Bus and desktop services.
8703 * Database Services:: SQL databases.
8704 * Mail Services:: IMAP, POP3, SMTP, and all that.
8705 * Messaging Services:: Messaging services.
8706 * Kerberos Services:: Kerberos services.
8707 * Web Services:: Web servers.
8708 * VPN Services:: VPN daemons.
8709 * Network File System:: NFS related services.
8710 * Continuous Integration:: The Cuirass service.
8711 * Power management Services:: The TLP tool.
8712 * Miscellaneous Services:: Other services.
8716 @subsubsection Base Services
8718 The @code{(gnu services base)} module provides definitions for the basic
8719 services that one expects from the system. The services exported by
8720 this module are listed below.
8722 @defvr {Scheme Variable} %base-services
8723 This variable contains a list of basic services (@pxref{Service Types
8724 and Services}, for more information on service objects) one would
8725 expect from the system: a login service (mingetty) on each tty, syslogd,
8726 the libc name service cache daemon (nscd), the udev device manager, and
8729 This is the default value of the @code{services} field of
8730 @code{operating-system} declarations. Usually, when customizing a
8731 system, you will want to append services to @var{%base-services}, like
8735 (cons* (avahi-service) (lsh-service) %base-services)
8739 @defvr {Scheme Variable} special-files-service-type
8740 This is the service that sets up ``special files'' such as
8741 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8743 The value associated with @code{special-files-service-type} services
8744 must be a list of tuples where the first element is the ``special file''
8745 and the second element is its target. By default it is:
8747 @cindex @file{/bin/sh}
8748 @cindex @file{sh}, in @file{/bin}
8750 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8753 @cindex @file{/usr/bin/env}
8754 @cindex @file{env}, in @file{/usr/bin}
8755 If you want to add, say, @code{/usr/bin/env} to your system, you can
8759 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8760 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8763 Since this is part of @code{%base-services}, you can use
8764 @code{modify-services} to customize the set of special files
8765 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8766 to add a special file is @i{via} the @code{extra-special-file} procedure
8770 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8771 Use @var{target} as the ``special file'' @var{file}.
8773 For example, adding the following lines to the @code{services} field of
8774 your operating system declaration leads to a @file{/usr/bin/env}
8778 (extra-special-file "/usr/bin/env"
8779 (file-append coreutils "/bin/env"))
8783 @deffn {Scheme Procedure} host-name-service @var{name}
8784 Return a service that sets the host name to @var{name}.
8787 @deffn {Scheme Procedure} login-service @var{config}
8788 Return a service to run login according to @var{config}, a
8789 @code{<login-configuration>} object, which specifies the message of the day,
8793 @deftp {Data Type} login-configuration
8794 This is the data type representing the configuration of login.
8799 @cindex message of the day
8800 A file-like object containing the ``message of the day''.
8802 @item @code{allow-empty-passwords?} (default: @code{#t})
8803 Allow empty passwords by default so that first-time users can log in when
8804 the 'root' account has just been created.
8809 @deffn {Scheme Procedure} mingetty-service @var{config}
8810 Return a service to run mingetty according to @var{config}, a
8811 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8815 @deftp {Data Type} mingetty-configuration
8816 This is the data type representing the configuration of Mingetty, which
8817 provides the default implementation of virtual console log-in.
8822 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8824 @item @code{auto-login} (default: @code{#f})
8825 When true, this field must be a string denoting the user name under
8826 which the system automatically logs in. When it is @code{#f}, a
8827 user name and password must be entered to log in.
8829 @item @code{login-program} (default: @code{#f})
8830 This must be either @code{#f}, in which case the default log-in program
8831 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8832 the name of the log-in program.
8834 @item @code{login-pause?} (default: @code{#f})
8835 When set to @code{#t} in conjunction with @var{auto-login}, the user
8836 will have to press a key before the log-in shell is launched.
8838 @item @code{mingetty} (default: @var{mingetty})
8839 The Mingetty package to use.
8844 @deffn {Scheme Procedure} agetty-service @var{config}
8845 Return a service to run agetty according to @var{config}, an
8846 @code{<agetty-configuration>} object, which specifies the tty to run,
8850 @deftp {Data Type} agetty-configuration
8851 This is the data type representing the configuration of agetty, which
8852 implements virtual and serial console log-in. See the @code{agetty(8)}
8853 man page for more information.
8858 The name of the console this agetty runs on, as a string---e.g.,
8859 @code{"ttyS0"}. This argument is mandatory.
8861 @item @code{baud-rate} (default: @code{#f})
8862 A string containing a comma-separated list of one or more baud rates, in
8865 @item @code{term} (default: @code{#f})
8866 A string containing the value used for the @code{TERM} environment
8869 @item @code{eight-bits?} (default: @code{#f})
8870 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8873 @item @code{auto-login} (default: @code{#f})
8874 When passed a login name, as a string, the specified user will be logged
8875 in automatically without prompting for their login name or password.
8877 @item @code{no-reset?} (default: @code{#f})
8878 When @code{#t}, don't reset terminal cflags (control modes).
8880 @item @code{host} (default: @code{#f})
8881 This accepts a string containing the "login_host", which will be written
8882 into the @file{/var/run/utmpx} file.
8884 @item @code{remote?} (default: @code{#f})
8885 When set to @code{#t} in conjunction with @var{host}, this will add an
8886 @code{-r} fakehost option to the command line of the login program
8887 specified in @var{login-program}.
8889 @item @code{flow-control?} (default: @code{#f})
8890 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8892 @item @code{no-issue?} (default: @code{#f})
8893 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8894 not be displayed before presenting the login prompt.
8896 @item @code{init-string} (default: @code{#f})
8897 This accepts a string that will be sent to the tty or modem before
8898 sending anything else. It can be used to initialize a modem.
8900 @item @code{no-clear?} (default: @code{#f})
8901 When set to @code{#t}, agetty will not clear the screen before showing
8904 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8905 This must be either a gexp denoting the name of a log-in program, or
8906 unset, in which case the default value is the @command{login} from the
8909 @item @code{local-line} (default: @code{#f})
8910 Control the CLOCAL line flag. This accepts one of three symbols as
8911 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8912 the default value chosen by agetty is @code{'auto}.
8914 @item @code{extract-baud?} (default: @code{#f})
8915 When set to @code{#t}, instruct agetty to try to extract the baud rate
8916 from the status messages produced by certain types of modems.
8918 @item @code{skip-login?} (default: @code{#f})
8919 When set to @code{#t}, do not prompt the user for a login name. This
8920 can be used with @var{login-program} field to use non-standard login
8923 @item @code{no-newline?} (default: @code{#f})
8924 When set to @code{#t}, do not print a newline before printing the
8925 @file{/etc/issue} file.
8927 @c Is this dangerous only when used with login-program, or always?
8928 @item @code{login-options} (default: @code{#f})
8929 This option accepts a string containing options that are passed to the
8930 login program. When used with the @var{login-program}, be aware that a
8931 malicious user could try to enter a login name containing embedded
8932 options that could be parsed by the login program.
8934 @item @code{login-pause} (default: @code{#f})
8935 When set to @code{#t}, wait for any key before showing the login prompt.
8936 This can be used in conjunction with @var{auto-login} to save memory by
8937 lazily spawning shells.
8939 @item @code{chroot} (default: @code{#f})
8940 Change root to the specified directory. This option accepts a directory
8943 @item @code{hangup?} (default: @code{#f})
8944 Use the Linux system call @code{vhangup} to do a virtual hangup of the
8947 @item @code{keep-baud?} (default: @code{#f})
8948 When set to @code{#t}, try to keep the existing baud rate. The baud
8949 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
8952 @item @code{timeout} (default: @code{#f})
8953 When set to an integer value, terminate if no user name could be read
8954 within @var{timeout} seconds.
8956 @item @code{detect-case?} (default: @code{#f})
8957 When set to @code{#t}, turn on support for detecting an uppercase-only
8958 terminal. This setting will detect a login name containing only
8959 uppercase letters as indicating an uppercase-only terminal and turn on
8960 some upper-to-lower case conversions. Note that this will not support
8963 @item @code{wait-cr?} (default: @code{#f})
8964 When set to @code{#t}, wait for the user or modem to send a
8965 carriage-return or linefeed character before displaying
8966 @file{/etc/issue} or login prompt. This is typically used with the
8967 @var{init-string} option.
8969 @item @code{no-hints?} (default: @code{#f})
8970 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
8973 @item @code{no-hostname?} (default: @code{#f})
8974 By default, the hostname is printed. When this option is set to
8975 @code{#t}, no hostname will be shown at all.
8977 @item @code{long-hostname?} (default: @code{#f})
8978 By default, the hostname is only printed until the first dot. When this
8979 option is set to @code{#t}, the fully qualified hostname by
8980 @code{gethostname} or @code{getaddrinfo} is shown.
8982 @item @code{erase-characters} (default: @code{#f})
8983 This option accepts a string of additional characters that should be
8984 interpreted as backspace when the user types their login name.
8986 @item @code{kill-characters} (default: @code{#f})
8987 This option accepts a string that should be interpreted to mean "ignore
8988 all previous characters" (also called a "kill" character) when the types
8991 @item @code{chdir} (default: @code{#f})
8992 This option accepts, as a string, a directory path that will be changed
8995 @item @code{delay} (default: @code{#f})
8996 This options accepts, as an integer, the number of seconds to sleep
8997 before opening the tty and displaying the login prompt.
8999 @item @code{nice} (default: @code{#f})
9000 This option accepts, as an integer, the nice value with which to run the
9001 @command{login} program.
9003 @item @code{extra-options} (default: @code{'()})
9004 This option provides an "escape hatch" for the user to provide arbitrary
9005 command-line arguments to @command{agetty} as a list of strings.
9010 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9011 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9012 according to @var{config}, a @code{<kmscon-configuration>} object, which
9013 specifies the tty to run, among other things.
9016 @deftp {Data Type} kmscon-configuration
9017 This is the data type representing the configuration of Kmscon, which
9018 implements virtual console log-in.
9022 @item @code{virtual-terminal}
9023 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9025 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9026 A gexp denoting the name of the log-in program. The default log-in program is
9027 @command{login} from the Shadow tool suite.
9029 @item @code{login-arguments} (default: @code{'("-p")})
9030 A list of arguments to pass to @command{login}.
9032 @item @code{hardware-acceleration?} (default: #f)
9033 Whether to use hardware acceleration.
9035 @item @code{kmscon} (default: @var{kmscon})
9036 The Kmscon package to use.
9041 @cindex name service cache daemon
9043 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9044 [#:name-services '()]
9045 Return a service that runs the libc name service cache daemon (nscd) with the
9046 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9047 Service Switch}, for an example.
9050 @defvr {Scheme Variable} %nscd-default-configuration
9051 This is the default @code{<nscd-configuration>} value (see below) used
9052 by @code{nscd-service}. It uses the caches defined by
9053 @var{%nscd-default-caches}; see below.
9056 @deftp {Data Type} nscd-configuration
9057 This is the data type representing the name service cache daemon (nscd)
9062 @item @code{name-services} (default: @code{'()})
9063 List of packages denoting @dfn{name services} that must be visible to
9064 the nscd---e.g., @code{(list @var{nss-mdns})}.
9066 @item @code{glibc} (default: @var{glibc})
9067 Package object denoting the GNU C Library providing the @command{nscd}
9070 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9071 Name of the nscd log file. This is where debugging output goes when
9072 @code{debug-level} is strictly positive.
9074 @item @code{debug-level} (default: @code{0})
9075 Integer denoting the debugging levels. Higher numbers mean that more
9076 debugging output is logged.
9078 @item @code{caches} (default: @var{%nscd-default-caches})
9079 List of @code{<nscd-cache>} objects denoting things to be cached; see
9085 @deftp {Data Type} nscd-cache
9086 Data type representing a cache database of nscd and its parameters.
9090 @item @code{database}
9091 This is a symbol representing the name of the database to be cached.
9092 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9093 @code{services}, which designate the corresponding NSS database
9094 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9096 @item @code{positive-time-to-live}
9097 @itemx @code{negative-time-to-live} (default: @code{20})
9098 A number representing the number of seconds during which a positive or
9099 negative lookup result remains in cache.
9101 @item @code{check-files?} (default: @code{#t})
9102 Whether to check for updates of the files corresponding to
9105 For instance, when @var{database} is @code{hosts}, setting this flag
9106 instructs nscd to check for updates in @file{/etc/hosts} and to take
9109 @item @code{persistent?} (default: @code{#t})
9110 Whether the cache should be stored persistently on disk.
9112 @item @code{shared?} (default: @code{#t})
9113 Whether the cache should be shared among users.
9115 @item @code{max-database-size} (default: 32@tie{}MiB)
9116 Maximum size in bytes of the database cache.
9118 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9119 @c settings, so leave them out.
9124 @defvr {Scheme Variable} %nscd-default-caches
9125 List of @code{<nscd-cache>} objects used by default by
9126 @code{nscd-configuration} (see above).
9128 It enables persistent and aggressive caching of service and host name
9129 lookups. The latter provides better host name lookup performance,
9130 resilience in the face of unreliable name servers, and also better
9131 privacy---often the result of host name lookups is in local cache, so
9132 external name servers do not even need to be queried.
9135 @anchor{syslog-configuration-type}
9138 @deftp {Data Type} syslog-configuration
9139 This data type represents the configuration of the syslog daemon.
9142 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9143 The syslog daemon to use.
9145 @item @code{config-file} (default: @code{%default-syslog.conf})
9146 The syslog configuration file to use.
9151 @anchor{syslog-service}
9153 @deffn {Scheme Procedure} syslog-service @var{config}
9154 Return a service that runs a syslog daemon according to @var{config}.
9156 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9157 information on the configuration file syntax.
9160 @anchor{guix-configuration-type}
9161 @deftp {Data Type} guix-configuration
9162 This data type represents the configuration of the Guix build daemon.
9163 @xref{Invoking guix-daemon}, for more information.
9166 @item @code{guix} (default: @var{guix})
9167 The Guix package to use.
9169 @item @code{build-group} (default: @code{"guixbuild"})
9170 Name of the group for build user accounts.
9172 @item @code{build-accounts} (default: @code{10})
9173 Number of build user accounts to create.
9175 @item @code{authorize-key?} (default: @code{#t})
9176 @cindex substitutes, authorization thereof
9177 Whether to authorize the substitute keys listed in
9178 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9179 (@pxref{Substitutes}).
9181 @vindex %default-authorized-guix-keys
9182 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9183 The list of authorized key files for archive imports, as a list of
9184 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9185 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9187 @item @code{use-substitutes?} (default: @code{#t})
9188 Whether to use substitutes.
9190 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9191 The list of URLs where to look for substitutes by default.
9193 @item @code{extra-options} (default: @code{'()})
9194 List of extra command-line options for @command{guix-daemon}.
9196 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9197 File where @command{guix-daemon}'s standard output and standard error
9200 @item @code{lsof} (default: @var{lsof})
9201 The lsof package to use.
9203 @item @code{http-proxy} (default: @code{#f})
9204 The HTTP proxy used for downloading fixed-output derivations and
9207 @item @code{tmpdir} (default: @code{#f})
9208 A directory path where the @command{guix-daemon} will perform builds.
9213 @deffn {Scheme Procedure} guix-service @var{config}
9214 Return a service that runs the Guix build daemon according to
9218 @deffn {Scheme Procedure} udev-service [#:udev udev]
9219 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9222 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9223 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9227 @defvr {Scheme Variable} %random-seed-file
9228 This is the name of the file where some random bytes are saved by
9229 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9230 It defaults to @file{/var/lib/random-seed}.
9235 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9236 @cindex keyboard layout
9237 Return a service to load console keymaps from @var{files} using
9238 @command{loadkeys} command. Most likely, you want to load some default
9239 keymap, which can be done like this:
9242 (console-keymap-service "dvorak")
9245 Or, for example, for a Swedish keyboard, you may need to combine
9246 the following keymaps:
9248 (console-keymap-service "se-lat6" "se-fi-lat6")
9251 Also you can specify a full file name (or file names) of your keymap(s).
9252 See @code{man loadkeys} for details.
9258 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9260 Run @var{gpm}, the general-purpose mouse daemon, with the given
9261 command-line @var{options}. GPM allows users to use the mouse in the console,
9262 notably to select, copy, and paste text. The default value of @var{options}
9263 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9265 This service is not part of @var{%base-services}.
9268 @anchor{guix-publish-service-type}
9269 @deffn {Scheme Variable} guix-publish-service-type
9270 This is the service type for @command{guix publish} (@pxref{Invoking
9271 guix publish}). Its value must be a @code{guix-configuration}
9272 object, as described below.
9274 This assumes that @file{/etc/guix} already contains a signing key pair as
9275 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9276 archive}). If that is not the case, the service will fail to start.
9279 @deftp {Data Type} guix-publish-configuration
9280 Data type representing the configuration of the @code{guix publish}
9284 @item @code{guix} (default: @code{guix})
9285 The Guix package to use.
9287 @item @code{port} (default: @code{80})
9288 The TCP port to listen for connections.
9290 @item @code{host} (default: @code{"localhost"})
9291 The host (and thus, network interface) to listen to. Use
9292 @code{"0.0.0.0"} to listen on all the network interfaces.
9294 @item @code{compression-level} (default: @code{3})
9295 The gzip compression level at which substitutes are compressed. Use
9296 @code{0} to disable compression altogether, and @code{9} to get the best
9297 compression ratio at the expense of increased CPU usage.
9299 @item @code{nar-path} (default: @code{"nar"})
9300 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9301 publish, @code{--nar-path}}, for details.
9303 @item @code{cache} (default: @code{#f})
9304 When it is @code{#f}, disable caching and instead generate archives on
9305 demand. Otherwise, this should be the name of a directory---e.g.,
9306 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9307 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9308 @option{--cache}}, for more information on the tradeoffs involved.
9310 @item @code{workers} (default: @code{#f})
9311 When it is an integer, this is the number of worker threads used for
9312 caching; when @code{#f}, the number of processors is used.
9313 @xref{Invoking guix publish, @option{--workers}}, for more information.
9315 @item @code{ttl} (default: @code{#f})
9316 When it is an integer, this denotes the @dfn{time-to-live} of the
9317 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9322 @anchor{rngd-service}
9323 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9324 [#:device "/dev/hwrng"]
9325 Return a service that runs the @command{rngd} program from @var{rng-tools}
9326 to add @var{device} to the kernel's entropy pool. The service will fail if
9327 @var{device} does not exist.
9330 @anchor{pam-limits-service}
9331 @cindex session limits
9334 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9336 Return a service that installs a configuration file for the
9337 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9338 @code{pam_limits} module}. The procedure optionally takes a list of
9339 @code{pam-limits-entry} values, which can be used to specify
9340 @code{ulimit} limits and nice priority limits to user sessions.
9342 The following limits definition sets two hard and soft limits for all
9343 login sessions of users in the @code{realtime} group:
9348 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9349 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9352 The first entry increases the maximum realtime priority for
9353 non-privileged processes; the second entry lifts any restriction of the
9354 maximum address space that can be locked in memory. These settings are
9355 commonly used for real-time audio systems.
9358 @node Scheduled Job Execution
9359 @subsubsection Scheduled Job Execution
9363 @cindex scheduling jobs
9364 The @code{(gnu services mcron)} module provides an interface to
9365 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9366 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9367 Unix @command{cron} daemon; the main difference is that it is
9368 implemented in Guile Scheme, which provides a lot of flexibility when
9369 specifying the scheduling of jobs and their actions.
9371 The example below defines an operating system that runs the
9372 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9373 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9374 well as the @command{mkid} command on behalf of an unprivileged user
9375 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9376 gexps to introduce job definitions that are passed to mcron
9377 (@pxref{G-Expressions}).
9380 (use-modules (guix) (gnu) (gnu services mcron))
9381 (use-package-modules base idutils)
9383 (define updatedb-job
9384 ;; Run 'updatedb' at 3AM every day. Here we write the
9385 ;; job's action as a Scheme procedure.
9386 #~(job '(next-hour '(3))
9388 (execl (string-append #$findutils "/bin/updatedb")
9390 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9392 (define garbage-collector-job
9393 ;; Collect garbage 5 minutes after midnight every day.
9394 ;; The job's action is a shell command.
9395 #~(job "5 0 * * *" ;Vixie cron syntax
9399 ;; Update the index database as user "charlie" at 12:15PM
9400 ;; and 19:15PM. This runs from the user's home directory.
9401 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9402 (string-append #$idutils "/bin/mkid src")
9407 (services (cons (mcron-service (list garbage-collector-job
9413 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9414 for more information on mcron job specifications. Below is the
9415 reference of the mcron service.
9417 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9418 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9419 list of gexps denoting mcron job specifications.
9421 This is a shorthand for:
9423 (service mcron-service-type
9424 (mcron-configuration (mcron mcron) (jobs jobs)))
9428 @defvr {Scheme Variable} mcron-service-type
9429 This is the type of the @code{mcron} service, whose value is an
9430 @code{mcron-configuration} object.
9432 This service type can be the target of a service extension that provides
9433 it additional job specifications (@pxref{Service Composition}). In
9434 other words, it is possible to define services that provide additional
9438 @deftp {Data Type} mcron-configuration
9439 Data type representing the configuration of mcron.
9442 @item @code{mcron} (default: @var{mcron2})
9443 The mcron package to use.
9446 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9447 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9448 specifications,, mcron, GNU@tie{}mcron}).
9454 @subsubsection Log Rotation
9457 @cindex log rotation
9459 Log files such as those found in @file{/var/log} tend to grow endlessly,
9460 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9461 their contents in separate files, possibly compressed. The @code{(gnu
9462 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9463 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9465 The example below defines an operating system that provides log rotation
9466 with the default settings.
9469 (use-modules (guix) (gnu))
9470 (use-service-modules admin mcron)
9471 (use-package-modules base idutils)
9475 (services (cons* (mcron-service)
9476 (service rottlog-service-type)
9480 @defvr {Scheme Variable} rottlog-service-type
9481 This is the type of the Rottlog service, whose value is a
9482 @code{rottlog-configuration} object.
9484 This service type can define mcron jobs (@pxref{Scheduled Job
9485 Execution}) to run the rottlog service.
9488 @deftp {Data Type} rottlog-configuration
9489 Data type representing the configuration of rottlog.
9492 @item @code{rottlog} (default: @code{rottlog})
9493 The Rottlog package to use.
9495 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9496 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9497 rottlog, GNU Rot[t]log Manual}).
9499 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9500 A list of Rottlog period-name/period-config tuples.
9502 For example, taking an example from the Rottlog manual (@pxref{Period
9503 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9507 ("daily" ,(plain-file "daily"
9509 /var/log/apache/* @{
9510 storedir apache-archives
9518 This is a list of gexps where each gexp corresponds to an mcron job
9519 specification (@pxref{Scheduled Job Execution}).
9523 @defvr {Scheme Variable} %default-rotations
9524 Specifies weekly rotation of @var{%rotated-files} and
9525 @code{"/var/log/shepherd.log"}.
9528 @defvr {Scheme Variable} %rotated-files
9529 The list of syslog-controlled files to be rotated. By default it is:
9530 @code{'("/var/log/messages" "/var/log/secure")}.
9533 @node Networking Services
9534 @subsubsection Networking Services
9536 The @code{(gnu services networking)} module provides services to configure
9537 the network interface.
9539 @cindex DHCP, networking service
9540 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9541 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9542 Protocol (DHCP) client, on all the non-loopback network interfaces.
9545 @defvr {Scheme Variable} static-networking-service-type
9546 This is the type for statically-configured network interfaces.
9547 @c TODO Document <static-networking> data structures.
9550 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9551 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9552 Return a service that starts @var{interface} with address @var{ip}. If
9553 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9554 it must be a string specifying the default network gateway.
9556 This procedure can be called several times, one for each network
9557 interface of interest. Behind the scenes what it does is extend
9558 @code{static-networking-service-type} with additional network interfaces
9565 @cindex network management
9566 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9567 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9568 management daemon that aims to simplify wired and wireless networking.
9570 This service adds the @var{wicd} package to the global profile, providing
9571 several commands to interact with the daemon and configure networking:
9572 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9573 and @command{wicd-curses} user interfaces.
9576 @cindex NetworkManager
9578 @defvr {Scheme Variable} network-manager-service-type
9579 This is the service type for the
9580 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9581 service. The value for this service type is a
9582 @code{network-manager-configuration} record.
9585 @deftp {Data Type} network-manager-configuration
9586 Data type representing the configuration of NetworkManager.
9589 @item @code{network-manager} (default: @code{network-manager})
9590 The NetworkManager package to use.
9592 @item @code{dns} (default: @code{"default"})
9593 Processing mode for DNS, which affects how NetworkManager uses the
9594 @code{resolv.conf} configuration file.
9598 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9599 provided by currently active connections.
9602 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9603 using a "split DNS" configuration if you are connected to a VPN, and
9604 then update @code{resolv.conf} to point to the local nameserver.
9607 NetworkManager will not modify @code{resolv.conf}.
9614 @deffn {Scheme Variable} connman-service-type
9615 This is the service type to run @url{https://01.org/connman,Connman},
9616 a network connection manager.
9618 Its value must be an
9619 @code{connman-configuration} record as in this example:
9622 (service connman-service-type
9623 (connman-configuration
9627 See below for details about @code{connman-configuration}.
9630 @deftp {Data Type} connman-configuration
9631 Data Type representing the configuration of connman.
9634 @item @code{connman} (default: @var{connman})
9635 The connman package to use.
9637 @item @code{disable-vpn?} (default: @code{#f})
9638 When true, enable connman's vpn plugin.
9642 @cindex WPA Supplicant
9643 @defvr {Scheme Variable} wpa-supplicant-service-type
9644 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9645 supplicant}, an authentication daemon required to authenticate against
9646 encrypted WiFi or ethernet networks. It is configured to listen for
9649 The value of this service is the @code{wpa-supplicant} package to use.
9650 Thus, it can be instantiated like this:
9653 (use-modules (gnu services networking))
9655 (service wpa-supplicant-service-type)
9660 @cindex real time clock
9661 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9662 [#:servers @var{%ntp-servers}] @
9663 [#:allow-large-adjustment? #f]
9664 Return a service that runs the daemon from @var{ntp}, the
9665 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9666 keep the system clock synchronized with that of @var{servers}.
9667 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9668 make an initial adjustment of more than 1,000 seconds.
9671 @defvr {Scheme Variable} %ntp-servers
9672 List of host names used as the default NTP servers.
9676 @deffn {Scheme variable} inetd-service-type
9677 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9678 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9679 connections on internet sockets, and lazily starts the specified server
9680 program when a connection is made on one of these sockets.
9682 The value of this service is an @code{inetd-configuration} object. The
9683 following example configures the @command{inetd} daemon to provide the
9684 built-in @command{echo} service, as well as an smtp service which
9685 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9686 gateway @code{hostname}:
9691 (inetd-configuration
9695 (socket-type 'stream)
9702 (socket-type 'stream)
9706 (program (file-append openssh "/bin/ssh"))
9708 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9709 "-W" "smtp-server:25" "user@@hostname")))))
9712 See below for more details about @code{inetd-configuration}.
9715 @deftp {Data Type} inetd-configuration
9716 Data type representing the configuration of @command{inetd}.
9719 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9720 The @command{inetd} executable to use.
9722 @item @code{entries} (default: @code{'()})
9723 A list of @command{inetd} service entries. Each entry should be created
9724 by the @code{inetd-entry} constructor.
9728 @deftp {Data Type} inetd-entry
9729 Data type representing an entry in the @command{inetd} configuration.
9730 Each entry corresponds to a socket where @command{inetd} will listen for
9734 @item @code{node} (default: @code{#f})
9735 Optional string, a comma-separated list of local addresses
9736 @command{inetd} should use when listening for this service.
9737 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9738 description of all options.
9740 A string, the name must correspond to an entry in @code{/etc/services}.
9741 @item @code{socket-type}
9742 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9744 @item @code{protocol}
9745 A string, must correspond to an entry in @code{/etc/protocols}.
9746 @item @code{wait?} (default: @code{#t})
9747 Whether @command{inetd} should wait for the server to exit before
9748 listening to new service requests.
9750 A string containing the user (and, optionally, group) name of the user
9751 as whom the server should run. The group name can be specified in a
9752 suffix, separated by a colon or period, i.e. @code{"user"},
9753 @code{"user:group"} or @code{"user.group"}.
9754 @item @code{program} (default: @code{"internal"})
9755 The server program which will serve the requests, or @code{"internal"}
9756 if @command{inetd} should use a built-in service.
9757 @item @code{arguments} (default: @code{'()})
9758 A list strings or file-like objects, which are the server program's
9759 arguments, starting with the zeroth argument, i.e. the name of the
9760 program itself. For @command{inetd}'s internal services, this entry
9761 must be @code{'()} or @code{'("internal")}.
9764 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9765 detailed discussion of each configuration field.
9769 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9770 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9773 The daemon runs as the @code{tor} unprivileged user. It is passed
9774 @var{config-file}, a file-like object, with an additional @code{User tor} line
9775 and lines for hidden services added via @code{tor-hidden-service}. Run
9776 @command{man tor} for information about the configuration file.
9779 @cindex hidden service
9780 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9781 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9782 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9785 '((22 "127.0.0.1:22")
9786 (80 "127.0.0.1:8080"))
9789 In this example, port 22 of the hidden service is mapped to local port 22, and
9790 port 80 is mapped to local port 8080.
9792 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9793 the @file{hostname} file contains the @code{.onion} host name for the hidden
9796 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9797 project's documentation} for more information.
9800 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9801 [#:interface "127.0.0.1"] [#:port 6667] @
9802 [#:extra-settings ""]
9803 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9804 acts as a gateway between IRC and chat networks.
9806 The daemon will listen to the interface corresponding to the IP address
9807 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9808 local clients can connect, whereas @code{0.0.0.0} means that connections can
9809 come from any networking interface.
9811 In addition, @var{extra-settings} specifies a string to append to the
9815 Furthermore, @code{(gnu services ssh)} provides the following services.
9819 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9820 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9821 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9822 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9823 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9824 [#:public-key-authentication? #t] [#:initialize? #t]
9825 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9826 @var{host-key} must designate a file containing the host key, and readable
9829 When @var{daemonic?} is true, @command{lshd} will detach from the
9830 controlling terminal and log its output to syslogd, unless one sets
9831 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9832 depend on existence of syslogd service. When @var{pid-file?} is true,
9833 @command{lshd} writes its PID to the file called @var{pid-file}.
9835 When @var{initialize?} is true, automatically create the seed and host key
9836 upon service activation if they do not exist yet. This may take long and
9837 require interaction.
9839 When @var{initialize?} is false, it is up to the user to initialize the
9840 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9841 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9842 basics,,, lsh, LSH Manual}).
9844 When @var{interfaces} is empty, lshd listens for connections on all the
9845 network interfaces; otherwise, @var{interfaces} must be a list of host names
9848 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9849 passwords, and @var{root-login?} specifies whether to accept log-ins as
9852 The other options should be self-descriptive.
9857 @deffn {Scheme Variable} openssh-service-type
9858 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9859 shell daemon, @command{sshd}. Its value must be an
9860 @code{openssh-configuration} record as in this example:
9863 (service openssh-service-type
9864 (openssh-configuration
9865 (x11-forwarding? #t)
9866 (permit-root-login 'without-password)))
9869 See below for details about @code{openssh-configuration}.
9872 @deftp {Data Type} openssh-configuration
9873 This is the configuration record for OpenSSH's @command{sshd}.
9876 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9877 Name of the file where @command{sshd} writes its PID.
9879 @item @code{port-number} (default: @code{22})
9880 TCP port on which @command{sshd} listens for incoming connections.
9882 @item @code{permit-root-login} (default: @code{#f})
9883 This field determines whether and when to allow logins as root. If
9884 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9885 If it's the symbol @code{'without-password}, then root logins are
9886 permitted but not with password-based authentication.
9888 @item @code{allow-empty-passwords?} (default: @code{#f})
9889 When true, users with empty passwords may log in. When false, they may
9892 @item @code{password-authentication?} (default: @code{#t})
9893 When true, users may log in with their password. When false, they have
9894 other authentication methods.
9896 @item @code{public-key-authentication?} (default: @code{#t})
9897 When true, users may log in using public key authentication. When
9898 false, users have to use other authentication method.
9900 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9901 This is used only by protocol version 2.
9903 @item @code{x11-forwarding?} (default: @code{#f})
9904 When true, forwarding of X11 graphical client connections is
9905 enabled---in other words, @command{ssh} options @option{-X} and
9906 @option{-Y} will work.
9908 @item @code{challenge-response-authentication?} (default: @code{#f})
9909 Specifies whether challenge response authentication is allowed (e.g. via
9912 @item @code{use-pam?} (default: @code{#t})
9913 Enables the Pluggable Authentication Module interface. If set to
9914 @code{#t}, this will enable PAM authentication using
9915 @code{challenge-response-authentication?} and
9916 @code{password-authentication?}, in addition to PAM account and session
9917 module processing for all authentication types.
9919 Because PAM challenge response authentication usually serves an
9920 equivalent role to password authentication, you should disable either
9921 @code{challenge-response-authentication?} or
9922 @code{password-authentication?}.
9924 @item @code{print-last-log?} (default: @code{#t})
9925 Specifies whether @command{sshd} should print the date and time of the
9926 last user login when a user logs in interactively.
9928 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
9929 Configures external subsystems (e.g. file transfer daemon).
9931 This is a list of two-element lists, each of which containing the
9932 subsystem name and a command (with optional arguments) to execute upon
9935 The command @command{internal-sftp} implements an in-process SFTP
9936 server. Alternately, one can specify the @command{sftp-server} command:
9938 (service openssh-service-type
9939 (openssh-configuration
9941 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
9946 @deffn {Scheme Procedure} dropbear-service [@var{config}]
9947 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
9948 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
9951 For example, to specify a Dropbear service listening on port 1234, add
9952 this call to the operating system's @code{services} field:
9955 (dropbear-service (dropbear-configuration
9956 (port-number 1234)))
9960 @deftp {Data Type} dropbear-configuration
9961 This data type represents the configuration of a Dropbear SSH daemon.
9964 @item @code{dropbear} (default: @var{dropbear})
9965 The Dropbear package to use.
9967 @item @code{port-number} (default: 22)
9968 The TCP port where the daemon waits for incoming connections.
9970 @item @code{syslog-output?} (default: @code{#t})
9971 Whether to enable syslog output.
9973 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
9974 File name of the daemon's PID file.
9976 @item @code{root-login?} (default: @code{#f})
9977 Whether to allow @code{root} logins.
9979 @item @code{allow-empty-passwords?} (default: @code{#f})
9980 Whether to allow empty passwords.
9982 @item @code{password-authentication?} (default: @code{#t})
9983 Whether to enable password-based authentication.
9987 @defvr {Scheme Variable} %facebook-host-aliases
9988 This variable contains a string for use in @file{/etc/hosts}
9989 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
9990 line contains a entry that maps a known server name of the Facebook
9991 on-line service---e.g., @code{www.facebook.com}---to the local
9992 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
9994 This variable is typically used in the @code{hosts-file} field of an
9995 @code{operating-system} declaration (@pxref{operating-system Reference,
9996 @file{/etc/hosts}}):
9999 (use-modules (gnu) (guix))
10002 (host-name "mymachine")
10005 ;; Create a /etc/hosts file with aliases for "localhost"
10006 ;; and "mymachine", as well as for Facebook servers.
10007 (plain-file "hosts"
10008 (string-append (local-host-aliases host-name)
10009 %facebook-host-aliases))))
10012 This mechanism can prevent programs running locally, such as Web
10013 browsers, from accessing Facebook.
10016 The @code{(gnu services avahi)} provides the following definition.
10018 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10019 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10020 [#:ipv6? #t] [#:wide-area? #f] @
10021 [#:domains-to-browse '()] [#:debug? #f]
10022 Return a service that runs @command{avahi-daemon}, a system-wide
10023 mDNS/DNS-SD responder that allows for service discovery and
10024 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10025 extends the name service cache daemon (nscd) so that it can resolve
10026 @code{.local} host names using
10027 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10028 add the @var{avahi} package to the system profile so that commands such as
10029 @command{avahi-browse} are directly usable.
10031 If @var{host-name} is different from @code{#f}, use that as the host name to
10032 publish for this machine; otherwise, use the machine's actual host name.
10034 When @var{publish?} is true, publishing of host names and services is allowed;
10035 in particular, avahi-daemon will publish the machine's host name and IP
10036 address via mDNS on the local network.
10038 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10040 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10044 @deffn {Scheme Variable} openvswitch-service-type
10045 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10046 service, whose value should be an @code{openvswitch-configuration}
10050 @deftp {Data Type} openvswitch-configuration
10051 Data type representing the configuration of Open vSwitch, a multilayer
10052 virtual switch which is designed to enable massive network automation
10053 through programmatic extension.
10056 @item @code{package} (default: @var{openvswitch})
10057 Package object of the Open vSwitch.
10063 @subsubsection X Window
10066 @cindex X Window System
10067 Support for the X Window graphical display system---specifically
10068 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10069 there is no @code{xorg-service} procedure. Instead, the X server is
10070 started by the @dfn{login manager}, currently SLiM.
10072 @deftp {Data Type} sddm-configuration
10073 This is the data type representing the sddm service configuration.
10076 @item @code{display-server} (default: "x11")
10077 Select display server to use for the greeter. Valid values are "x11"
10080 @item @code{numlock} (default: "on")
10081 Valid values are "on", "off" or "none".
10083 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10084 Command to run when halting.
10086 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10087 Command to run when rebooting.
10089 @item @code{theme} (default "maldives")
10090 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10092 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10093 Directory to look for themes.
10095 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10096 Directory to look for faces.
10098 @item @code{default-path} (default "/run/current-system/profile/bin")
10099 Default PATH to use.
10101 @item @code{minimum-uid} (default 1000)
10102 Minimum UID to display in SDDM.
10104 @item @code{maximum-uid} (default 2000)
10105 Maximum UID to display in SDDM
10107 @item @code{remember-last-user?} (default #t)
10108 Remember last user.
10110 @item @code{remember-last-session?} (default #t)
10111 Remember last session.
10113 @item @code{hide-users} (default "")
10114 Usernames to hide from SDDM greeter.
10116 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10117 Users with shells listed will be hidden from the SDDM greeter.
10119 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10120 Script to run before starting a wayland session.
10122 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10123 Directory to look for desktop files starting wayland sessions.
10125 @item @code{xorg-server-path} (default @code{xorg-start-command})
10126 Path to xorg-server.
10128 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10131 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10134 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10135 Script to run after starting xorg-server.
10137 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10138 Script to run before stopping xorg-server.
10140 @item @code{xsession-command} (default: @code{xinitr })
10141 Script to run before starting a X session.
10143 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10144 Directory to look for desktop files starting X sessions.
10146 @item @code{minimum-vt} (default: 7)
10149 @item @code{xserver-arguments} (default "-nolisten tcp")
10150 Arguments to pass to xorg-server.
10152 @item @code{auto-login-user} (default "")
10153 User to use for auto-login.
10155 @item @code{auto-login-session} (default "")
10156 Desktop file to use for auto-login.
10158 @item @code{relogin?} (default #f)
10159 Relogin after logout.
10164 @cindex login manager
10165 @deffn {Scheme Procedure} sddm-service config
10166 Return a service that spawns the SDDM graphical login manager for config of
10167 type @code{<sddm-configuration>}.
10170 (sddm-service (sddm-configuration
10171 (auto-login-user "Alice")
10172 (auto-login-session "xfce.desktop")))
10176 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10177 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10178 [#:theme @var{%default-slim-theme}] @
10179 [#:theme-name @var{%default-slim-theme-name}]
10180 Return a service that spawns the SLiM graphical login manager, which in
10181 turn starts the X display server with @var{startx}, a command as returned by
10182 @code{xorg-start-command}.
10186 SLiM automatically looks for session types described by the @file{.desktop}
10187 files in @file{/run/current-system/profile/share/xsessions} and allows users
10188 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10189 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10190 adding them to the system-wide set of packages automatically makes them
10191 available at the log-in screen.
10193 In addition, @file{~/.xsession} files are honored. When available,
10194 @file{~/.xsession} must be an executable that starts a window manager
10195 and/or other X clients.
10197 When @var{allow-empty-passwords?} is true, allow logins with an empty
10198 password. When @var{auto-login?} is true, log in automatically as
10199 @var{default-user}.
10201 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10202 @var{theme} must be a gexp denoting the name of a directory containing the
10203 theme to use. In that case, @var{theme-name} specifies the name of the
10207 @defvr {Scheme Variable} %default-theme
10208 @defvrx {Scheme Variable} %default-theme-name
10209 The G-Expression denoting the default SLiM theme and its name.
10212 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10213 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10214 Return a derivation that builds a @var{guile} script to start the X server
10215 from @var{xorg-server}. @var{configuration-file} is the server configuration
10216 file or a derivation that builds it; when omitted, the result of
10217 @code{xorg-configuration-file} is used.
10219 Usually the X server is started by a login manager.
10222 @deffn {Scheme Procedure} xorg-configuration-file @
10223 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10224 Return a configuration file for the Xorg server containing search paths for
10225 all the common drivers.
10227 @var{drivers} must be either the empty list, in which case Xorg chooses a
10228 graphics driver automatically, or a list of driver names that will be tried in
10229 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10231 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10232 appropriate screen resolution; otherwise, it must be a list of
10233 resolutions---e.g., @code{((1024 768) (640 480))}.
10235 Last, @var{extra-config} is a list of strings or objects appended to the
10236 @code{text-file*} argument list. It is used to pass extra text to be added
10237 verbatim to the configuration file.
10240 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10241 Add @var{package}, a package for a screen-locker or screen-saver whose
10242 command is @var{program}, to the set of setuid programs and add a PAM entry
10243 for it. For example:
10246 (screen-locker-service xlockmore "xlock")
10249 makes the good ol' XlockMore usable.
10253 @node Printing Services
10254 @subsubsection Printing Services
10256 @cindex printer support with CUPS
10257 The @code{(gnu services cups)} module provides a Guix service definition
10258 for the CUPS printing service. To add printer support to a GuixSD
10259 system, add a @code{cups-service} to the operating system definition:
10261 @deffn {Scheme Variable} cups-service-type
10262 The service type for the CUPS print server. Its value should be a valid
10263 CUPS configuration (see below). To use the default settings, simply
10266 (service cups-service-type)
10270 The CUPS configuration controls the basic things about your CUPS
10271 installation: what interfaces it listens on, what to do if a print job
10272 fails, how much logging to do, and so on. To actually add a printer,
10273 you have to visit the @url{http://localhost:631} URL, or use a tool such
10274 as GNOME's printer configuration services. By default, configuring a
10275 CUPS service will generate a self-signed certificate if needed, for
10276 secure connections to the print server.
10278 Suppose you want to enable the Web interface of CUPS and also add
10279 support for HP printers @i{via} the @code{hplip} package. You can do
10280 that directly, like this (you need to use the @code{(gnu packages cups)}
10284 (service cups-service-type
10285 (cups-configuration
10286 (web-interface? #t)
10288 (list cups-filters hplip))))
10291 The available configuration parameters follow. Each parameter
10292 definition is preceded by its type; for example, @samp{string-list foo}
10293 indicates that the @code{foo} parameter should be specified as a list of
10294 strings. There is also a way to specify the configuration as a string,
10295 if you have an old @code{cupsd.conf} file that you want to port over
10296 from some other system; see the end for more details.
10298 @c The following documentation was initially generated by
10299 @c (generate-documentation) in (gnu services cups). Manually maintained
10300 @c documentation is better, so we shouldn't hesitate to edit below as
10301 @c needed. However if the change you want to make to this documentation
10302 @c can be done in an automated way, it's probably easier to change
10303 @c (generate-documentation) than to make it below and have to deal with
10304 @c the churn as CUPS updates.
10307 Available @code{cups-configuration} fields are:
10309 @deftypevr {@code{cups-configuration} parameter} package cups
10313 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10314 Drivers and other extensions to the CUPS package.
10317 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10318 Configuration of where to write logs, what directories to use for print
10319 spools, and related privileged configuration parameters.
10321 Available @code{files-configuration} fields are:
10323 @deftypevr {@code{files-configuration} parameter} log-location access-log
10324 Defines the access log filename. Specifying a blank filename disables
10325 access log generation. The value @code{stderr} causes log entries to be
10326 sent to the standard error file when the scheduler is running in the
10327 foreground, or to the system log daemon when run in the background. The
10328 value @code{syslog} causes log entries to be sent to the system log
10329 daemon. The server name may be included in filenames using the string
10330 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10332 Defaults to @samp{"/var/log/cups/access_log"}.
10335 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10336 Where CUPS should cache data.
10338 Defaults to @samp{"/var/cache/cups"}.
10341 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10342 Specifies the permissions for all configuration files that the scheduler
10345 Note that the permissions for the printers.conf file are currently
10346 masked to only allow access from the scheduler user (typically root).
10347 This is done because printer device URIs sometimes contain sensitive
10348 authentication information that should not be generally known on the
10349 system. There is no way to disable this security feature.
10351 Defaults to @samp{"0640"}.
10354 @deftypevr {@code{files-configuration} parameter} log-location error-log
10355 Defines the error log filename. Specifying a blank filename disables
10356 access log generation. The value @code{stderr} causes log entries to be
10357 sent to the standard error file when the scheduler is running in the
10358 foreground, or to the system log daemon when run in the background. The
10359 value @code{syslog} causes log entries to be sent to the system log
10360 daemon. The server name may be included in filenames using the string
10361 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10363 Defaults to @samp{"/var/log/cups/error_log"}.
10366 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10367 Specifies which errors are fatal, causing the scheduler to exit. The
10372 No errors are fatal.
10375 All of the errors below are fatal.
10378 Browsing initialization errors are fatal, for example failed connections
10379 to the DNS-SD daemon.
10382 Configuration file syntax errors are fatal.
10385 Listen or Port errors are fatal, except for IPv6 failures on the
10386 loopback or @code{any} addresses.
10389 Log file creation or write errors are fatal.
10392 Bad startup file permissions are fatal, for example shared TLS
10393 certificate and key files with world-read permissions.
10396 Defaults to @samp{"all -browse"}.
10399 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10400 Specifies whether the file pseudo-device can be used for new printer
10401 queues. The URI @uref{file:///dev/null} is always allowed.
10403 Defaults to @samp{#f}.
10406 @deftypevr {@code{files-configuration} parameter} string group
10407 Specifies the group name or ID that will be used when executing external
10410 Defaults to @samp{"lp"}.
10413 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10414 Specifies the permissions for all log files that the scheduler writes.
10416 Defaults to @samp{"0644"}.
10419 @deftypevr {@code{files-configuration} parameter} log-location page-log
10420 Defines the page log filename. Specifying a blank filename disables
10421 access log generation. The value @code{stderr} causes log entries to be
10422 sent to the standard error file when the scheduler is running in the
10423 foreground, or to the system log daemon when run in the background. The
10424 value @code{syslog} causes log entries to be sent to the system log
10425 daemon. The server name may be included in filenames using the string
10426 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10428 Defaults to @samp{"/var/log/cups/page_log"}.
10431 @deftypevr {@code{files-configuration} parameter} string remote-root
10432 Specifies the username that is associated with unauthenticated accesses
10433 by clients claiming to be the root user. The default is @code{remroot}.
10435 Defaults to @samp{"remroot"}.
10438 @deftypevr {@code{files-configuration} parameter} file-name request-root
10439 Specifies the directory that contains print jobs and other HTTP request
10442 Defaults to @samp{"/var/spool/cups"}.
10445 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10446 Specifies the level of security sandboxing that is applied to print
10447 filters, backends, and other child processes of the scheduler; either
10448 @code{relaxed} or @code{strict}. This directive is currently only
10449 used/supported on macOS.
10451 Defaults to @samp{strict}.
10454 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10455 Specifies the location of TLS certificates and private keys. CUPS will
10456 look for public and private keys in this directory: a @code{.crt} files
10457 for PEM-encoded certificates and corresponding @code{.key} files for
10458 PEM-encoded private keys.
10460 Defaults to @samp{"/etc/cups/ssl"}.
10463 @deftypevr {@code{files-configuration} parameter} file-name server-root
10464 Specifies the directory containing the server configuration files.
10466 Defaults to @samp{"/etc/cups"}.
10469 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10470 Specifies whether the scheduler calls fsync(2) after writing
10471 configuration or state files.
10473 Defaults to @samp{#f}.
10476 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10477 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10480 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10481 Specifies the directory where temporary files are stored.
10483 Defaults to @samp{"/var/spool/cups/tmp"}.
10486 @deftypevr {@code{files-configuration} parameter} string user
10487 Specifies the user name or ID that is used when running external
10490 Defaults to @samp{"lp"}.
10494 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10495 Specifies the logging level for the AccessLog file. The @code{config}
10496 level logs when printers and classes are added, deleted, or modified and
10497 when configuration files are accessed or updated. The @code{actions}
10498 level logs when print jobs are submitted, held, released, modified, or
10499 canceled, and any of the conditions for @code{config}. The @code{all}
10500 level logs all requests.
10502 Defaults to @samp{actions}.
10505 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10506 Specifies whether to purge job history data automatically when it is no
10507 longer required for quotas.
10509 Defaults to @samp{#f}.
10512 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10513 Specifies which protocols to use for local printer sharing.
10515 Defaults to @samp{dnssd}.
10518 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10519 Specifies whether the CUPS web interface is advertised.
10521 Defaults to @samp{#f}.
10524 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10525 Specifies whether shared printers are advertised.
10527 Defaults to @samp{#f}.
10530 @deftypevr {@code{cups-configuration} parameter} string classification
10531 Specifies the security classification of the server. Any valid banner
10532 name can be used, including "classified", "confidential", "secret",
10533 "topsecret", and "unclassified", or the banner can be omitted to disable
10534 secure printing functions.
10536 Defaults to @samp{""}.
10539 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10540 Specifies whether users may override the classification (cover page) of
10541 individual print jobs using the @code{job-sheets} option.
10543 Defaults to @samp{#f}.
10546 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10547 Specifies the default type of authentication to use.
10549 Defaults to @samp{Basic}.
10552 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10553 Specifies whether encryption will be used for authenticated requests.
10555 Defaults to @samp{Required}.
10558 @deftypevr {@code{cups-configuration} parameter} string default-language
10559 Specifies the default language to use for text and web content.
10561 Defaults to @samp{"en"}.
10564 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10565 Specifies the default paper size for new print queues. @samp{"Auto"}
10566 uses a locale-specific default, while @samp{"None"} specifies there is
10567 no default paper size. Specific size names are typically
10568 @samp{"Letter"} or @samp{"A4"}.
10570 Defaults to @samp{"Auto"}.
10573 @deftypevr {@code{cups-configuration} parameter} string default-policy
10574 Specifies the default access policy to use.
10576 Defaults to @samp{"default"}.
10579 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10580 Specifies whether local printers are shared by default.
10582 Defaults to @samp{#t}.
10585 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10586 Specifies the delay for updating of configuration and state files, in
10587 seconds. A value of 0 causes the update to happen as soon as possible,
10588 typically within a few milliseconds.
10590 Defaults to @samp{30}.
10593 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10594 Specifies what to do when an error occurs. Possible values are
10595 @code{abort-job}, which will discard the failed print job;
10596 @code{retry-job}, which will retry the job at a later time;
10597 @code{retry-this-job}, which retries the failed job immediately; and
10598 @code{stop-printer}, which stops the printer.
10600 Defaults to @samp{stop-printer}.
10603 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10604 Specifies the maximum cost of filters that are run concurrently, which
10605 can be used to minimize disk, memory, and CPU resource problems. A
10606 limit of 0 disables filter limiting. An average print to a
10607 non-PostScript printer needs a filter limit of about 200. A PostScript
10608 printer needs about half that (100). Setting the limit below these
10609 thresholds will effectively limit the scheduler to printing a single job
10612 Defaults to @samp{0}.
10615 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10616 Specifies the scheduling priority of filters that are run to print a
10617 job. The nice value ranges from 0, the highest priority, to 19, the
10620 Defaults to @samp{0}.
10623 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10624 Specifies whether to do reverse lookups on connecting clients. The
10625 @code{double} setting causes @code{cupsd} to verify that the hostname
10626 resolved from the address matches one of the addresses returned for that
10627 hostname. Double lookups also prevent clients with unregistered
10628 addresses from connecting to your server. Only set this option to
10629 @code{#t} or @code{double} if absolutely required.
10631 Defaults to @samp{#f}.
10634 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10635 Specifies the number of seconds to wait before killing the filters and
10636 backend associated with a canceled or held job.
10638 Defaults to @samp{30}.
10641 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10642 Specifies the interval between retries of jobs in seconds. This is
10643 typically used for fax queues but can also be used with normal print
10644 queues whose error policy is @code{retry-job} or
10645 @code{retry-current-job}.
10647 Defaults to @samp{30}.
10650 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10651 Specifies the number of retries that are done for jobs. This is
10652 typically used for fax queues but can also be used with normal print
10653 queues whose error policy is @code{retry-job} or
10654 @code{retry-current-job}.
10656 Defaults to @samp{5}.
10659 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10660 Specifies whether to support HTTP keep-alive connections.
10662 Defaults to @samp{#t}.
10665 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10666 Specifies how long an idle client connection remains open, in seconds.
10668 Defaults to @samp{30}.
10671 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10672 Specifies the maximum size of print files, IPP requests, and HTML form
10673 data. A limit of 0 disables the limit check.
10675 Defaults to @samp{0}.
10678 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10679 Listens on the specified interfaces for connections. Valid values are
10680 of the form @var{address}:@var{port}, where @var{address} is either an
10681 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10682 indicate all addresses. Values can also be file names of local UNIX
10683 domain sockets. The Listen directive is similar to the Port directive
10684 but allows you to restrict access to specific interfaces or networks.
10687 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10688 Specifies the number of pending connections that will be allowed. This
10689 normally only affects very busy servers that have reached the MaxClients
10690 limit, but can also be triggered by large numbers of simultaneous
10691 connections. When the limit is reached, the operating system will
10692 refuse additional connections until the scheduler can accept the pending
10695 Defaults to @samp{128}.
10698 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10699 Specifies a set of additional access controls.
10701 Available @code{location-access-controls} fields are:
10703 @deftypevr {@code{location-access-controls} parameter} file-name path
10704 Specifies the URI path to which the access control applies.
10707 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10708 Access controls for all access to this path, in the same format as the
10709 @code{access-controls} of @code{operation-access-control}.
10711 Defaults to @samp{()}.
10714 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10715 Access controls for method-specific access to this path.
10717 Defaults to @samp{()}.
10719 Available @code{method-access-controls} fields are:
10721 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10722 If @code{#t}, apply access controls to all methods except the listed
10723 methods. Otherwise apply to only the listed methods.
10725 Defaults to @samp{#f}.
10728 @deftypevr {@code{method-access-controls} parameter} method-list methods
10729 Methods to which this access control applies.
10731 Defaults to @samp{()}.
10734 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10735 Access control directives, as a list of strings. Each string should be
10736 one directive, such as "Order allow,deny".
10738 Defaults to @samp{()}.
10743 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10744 Specifies the number of debugging messages that are retained for logging
10745 if an error occurs in a print job. Debug messages are logged regardless
10746 of the LogLevel setting.
10748 Defaults to @samp{100}.
10751 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10752 Specifies the level of logging for the ErrorLog file. The value
10753 @code{none} stops all logging while @code{debug2} logs everything.
10755 Defaults to @samp{info}.
10758 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10759 Specifies the format of the date and time in the log files. The value
10760 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10762 Defaults to @samp{standard}.
10765 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10766 Specifies the maximum number of simultaneous clients that are allowed by
10769 Defaults to @samp{100}.
10772 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10773 Specifies the maximum number of simultaneous clients that are allowed
10774 from a single address.
10776 Defaults to @samp{100}.
10779 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10780 Specifies the maximum number of copies that a user can print of each
10783 Defaults to @samp{9999}.
10786 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10787 Specifies the maximum time a job may remain in the @code{indefinite}
10788 hold state before it is canceled. A value of 0 disables cancellation of
10791 Defaults to @samp{0}.
10794 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10795 Specifies the maximum number of simultaneous jobs that are allowed. Set
10796 to 0 to allow an unlimited number of jobs.
10798 Defaults to @samp{500}.
10801 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10802 Specifies the maximum number of simultaneous jobs that are allowed per
10803 printer. A value of 0 allows up to MaxJobs jobs per printer.
10805 Defaults to @samp{0}.
10808 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10809 Specifies the maximum number of simultaneous jobs that are allowed per
10810 user. A value of 0 allows up to MaxJobs jobs per user.
10812 Defaults to @samp{0}.
10815 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10816 Specifies the maximum time a job may take to print before it is
10817 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10819 Defaults to @samp{10800}.
10822 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10823 Specifies the maximum size of the log files before they are rotated, in
10824 bytes. The value 0 disables log rotation.
10826 Defaults to @samp{1048576}.
10829 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10830 Specifies the maximum amount of time to allow between files in a
10831 multiple file print job, in seconds.
10833 Defaults to @samp{300}.
10836 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10837 Specifies the format of PageLog lines. Sequences beginning with percent
10838 (@samp{%}) characters are replaced with the corresponding information,
10839 while all other characters are copied literally. The following percent
10840 sequences are recognized:
10844 insert a single percent character
10847 insert the value of the specified IPP attribute
10850 insert the number of copies for the current page
10853 insert the current page number
10856 insert the current date and time in common log format
10862 insert the printer name
10865 insert the username
10868 A value of the empty string disables page logging. The string @code{%p
10869 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10870 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10873 Defaults to @samp{""}.
10876 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10877 Passes the specified environment variable(s) to child processes; a list
10880 Defaults to @samp{()}.
10883 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10884 Specifies named access control policies.
10886 Available @code{policy-configuration} fields are:
10888 @deftypevr {@code{policy-configuration} parameter} string name
10889 Name of the policy.
10892 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10893 Specifies an access list for a job's private values. @code{@@ACL} maps
10894 to the printer's requesting-user-name-allowed or
10895 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10896 owner. @code{@@SYSTEM} maps to the groups listed for the
10897 @code{system-group} field of the @code{files-config} configuration,
10898 which is reified into the @code{cups-files.conf(5)} file. Other
10899 possible elements of the access list include specific user names, and
10900 @code{@@@var{group}} to indicate members of a specific group. The
10901 access list may also be simply @code{all} or @code{default}.
10903 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10906 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10907 Specifies the list of job values to make private, or @code{all},
10908 @code{default}, or @code{none}.
10910 Defaults to @samp{"job-name job-originating-host-name
10911 job-originating-user-name phone"}.
10914 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10915 Specifies an access list for a subscription's private values.
10916 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10917 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10918 owner. @code{@@SYSTEM} maps to the groups listed for the
10919 @code{system-group} field of the @code{files-config} configuration,
10920 which is reified into the @code{cups-files.conf(5)} file. Other
10921 possible elements of the access list include specific user names, and
10922 @code{@@@var{group}} to indicate members of a specific group. The
10923 access list may also be simply @code{all} or @code{default}.
10925 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10928 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
10929 Specifies the list of job values to make private, or @code{all},
10930 @code{default}, or @code{none}.
10932 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
10933 notify-subscriber-user-name notify-user-data"}.
10936 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
10937 Access control by IPP operation.
10939 Defaults to @samp{()}.
10943 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
10944 Specifies whether job files (documents) are preserved after a job is
10945 printed. If a numeric value is specified, job files are preserved for
10946 the indicated number of seconds after printing. Otherwise a boolean
10947 value applies indefinitely.
10949 Defaults to @samp{86400}.
10952 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
10953 Specifies whether the job history is preserved after a job is printed.
10954 If a numeric value is specified, the job history is preserved for the
10955 indicated number of seconds after printing. If @code{#t}, the job
10956 history is preserved until the MaxJobs limit is reached.
10958 Defaults to @samp{#t}.
10961 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
10962 Specifies the amount of time to wait for job completion before
10963 restarting the scheduler.
10965 Defaults to @samp{30}.
10968 @deftypevr {@code{cups-configuration} parameter} string rip-cache
10969 Specifies the maximum amount of memory to use when converting documents
10970 into bitmaps for a printer.
10972 Defaults to @samp{"128m"}.
10975 @deftypevr {@code{cups-configuration} parameter} string server-admin
10976 Specifies the email address of the server administrator.
10978 Defaults to @samp{"root@@localhost.localdomain"}.
10981 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
10982 The ServerAlias directive is used for HTTP Host header validation when
10983 clients connect to the scheduler from external interfaces. Using the
10984 special name @code{*} can expose your system to known browser-based DNS
10985 rebinding attacks, even when accessing sites through a firewall. If the
10986 auto-discovery of alternate names does not work, we recommend listing
10987 each alternate name with a ServerAlias directive instead of using
10990 Defaults to @samp{*}.
10993 @deftypevr {@code{cups-configuration} parameter} string server-name
10994 Specifies the fully-qualified host name of the server.
10996 Defaults to @samp{"localhost"}.
10999 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11000 Specifies what information is included in the Server header of HTTP
11001 responses. @code{None} disables the Server header. @code{ProductOnly}
11002 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11003 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11004 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11005 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11006 2.0.0 (@var{uname}) IPP/2.0}.
11008 Defaults to @samp{Minimal}.
11011 @deftypevr {@code{cups-configuration} parameter} string set-env
11012 Set the specified environment variable to be passed to child processes.
11014 Defaults to @samp{"variable value"}.
11017 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11018 Listens on the specified interfaces for encrypted connections. Valid
11019 values are of the form @var{address}:@var{port}, where @var{address} is
11020 either an IPv6 address enclosed in brackets, an IPv4 address, or
11021 @code{*} to indicate all addresses.
11023 Defaults to @samp{()}.
11026 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11027 Sets encryption options. By default, CUPS only supports encryption
11028 using TLS v1.0 or higher using known secure cipher suites. The
11029 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11030 required for some older clients that do not implement newer ones. The
11031 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11032 older clients that do not support TLS v1.0.
11034 Defaults to @samp{()}.
11037 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11038 Specifies whether the scheduler requires clients to strictly adhere to
11039 the IPP specifications.
11041 Defaults to @samp{#f}.
11044 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11045 Specifies the HTTP request timeout, in seconds.
11047 Defaults to @samp{300}.
11051 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11052 Specifies whether the web interface is enabled.
11054 Defaults to @samp{#f}.
11057 At this point you're probably thinking ``oh dear, Guix manual, I like
11058 you but you can stop already with the configuration options''. Indeed.
11059 However, one more point: it could be that you have an existing
11060 @code{cupsd.conf} that you want to use. In that case, you can pass an
11061 @code{opaque-cups-configuration} as the configuration of a
11062 @code{cups-service-type}.
11064 Available @code{opaque-cups-configuration} fields are:
11066 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11070 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11071 The contents of the @code{cupsd.conf}, as a string.
11074 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11075 The contents of the @code{cups-files.conf} file, as a string.
11078 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11079 strings of the same name, you could instantiate a CUPS service like
11083 (service cups-service-type
11084 (opaque-cups-configuration
11085 (cupsd.conf cupsd.conf)
11086 (cups-files.conf cups-files.conf)))
11090 @node Desktop Services
11091 @subsubsection Desktop Services
11093 The @code{(gnu services desktop)} module provides services that are
11094 usually useful in the context of a ``desktop'' setup---that is, on a
11095 machine running a graphical display server, possibly with graphical user
11096 interfaces, etc. It also defines services that provide specific desktop
11097 environments like GNOME and XFCE.
11099 To simplify things, the module defines a variable containing the set of
11100 services that users typically expect on a machine with a graphical
11101 environment and networking:
11103 @defvr {Scheme Variable} %desktop-services
11104 This is a list of services that builds upon @var{%base-services} and
11105 adds or adjusts services for a typical ``desktop'' setup.
11107 In particular, it adds a graphical login manager (@pxref{X Window,
11108 @code{slim-service}}), screen lockers,
11109 a network management tool (@pxref{Networking
11110 Services, @code{wicd-service}}), energy and color management services,
11111 the @code{elogind} login and seat manager, the Polkit privilege service,
11112 the GeoClue location service, an NTP client (@pxref{Networking
11113 Services}), the Avahi daemon, and has the name service switch service
11114 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11118 The @var{%desktop-services} variable can be used as the @code{services}
11119 field of an @code{operating-system} declaration (@pxref{operating-system
11120 Reference, @code{services}}).
11122 Additionally, the @code{gnome-desktop-service} and
11123 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11124 system. To ``add GNOME'' means that system-level services like the
11125 backlight adjustment helpers and the power management utilities are
11126 added to the system, extending @code{polkit} and @code{dbus}
11127 appropriately, allowing GNOME to operate with elevated privileges on a
11128 limited number of special-purpose system interfaces. Additionally,
11129 adding a service made by @code{gnome-desktop-service} adds the GNOME
11130 metapackage to the system profile. Likewise, adding the XFCE service
11131 not only adds the @code{xfce} metapackage to the system profile, but it
11132 also gives the Thunar file manager the ability to open a ``root-mode''
11133 file management window, if the user authenticates using the
11134 administrator's password via the standard polkit graphical interface.
11136 @deffn {Scheme Procedure} gnome-desktop-service
11137 Return a service that adds the @code{gnome} package to the system
11138 profile, and extends polkit with the actions from
11139 @code{gnome-settings-daemon}.
11142 @deffn {Scheme Procedure} xfce-desktop-service
11143 Return a service that adds the @code{xfce} package to the system profile,
11144 and extends polkit with the ability for @code{thunar} to manipulate the
11145 file system as root from within a user session, after the user has
11146 authenticated with the administrator's password.
11149 Because the GNOME and XFCE desktop services pull in so many packages,
11150 the default @code{%desktop-services} variable doesn't include either of
11151 them by default. To add GNOME or XFCE, just @code{cons} them onto
11152 @code{%desktop-services} in the @code{services} field of your
11153 @code{operating-system}:
11156 (use-modules (gnu))
11157 (use-service-modules desktop)
11160 ;; cons* adds items to the list given as its last argument.
11161 (services (cons* (gnome-desktop-service)
11162 (xfce-desktop-service)
11163 %desktop-services))
11167 These desktop environments will then be available as options in the
11168 graphical login window.
11170 The actual service definitions included in @code{%desktop-services} and
11171 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11172 are described below.
11174 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11175 Return a service that runs the ``system bus'', using @var{dbus}, with
11176 support for @var{services}.
11178 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11179 facility. Its system bus is used to allow system services to communicate
11180 and to be notified of system-wide events.
11182 @var{services} must be a list of packages that provide an
11183 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11184 and policy files. For example, to allow avahi-daemon to use the system bus,
11185 @var{services} must be equal to @code{(list avahi)}.
11188 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11189 Return a service that runs the @code{elogind} login and
11190 seat management daemon. @uref{https://github.com/andywingo/elogind,
11191 Elogind} exposes a D-Bus interface that can be used to know which users
11192 are logged in, know what kind of sessions they have open, suspend the
11193 system, inhibit system suspend, reboot the system, and other tasks.
11195 Elogind handles most system-level power events for a computer, for
11196 example suspending the system when a lid is closed, or shutting it down
11197 when the power button is pressed.
11199 The @var{config} keyword argument specifies the configuration for
11200 elogind, and should be the result of an @code{(elogind-configuration
11201 (@var{parameter} @var{value})...)} invocation. Available parameters and
11202 their default values are:
11205 @item kill-user-processes?
11207 @item kill-only-users
11209 @item kill-exclude-users
11211 @item inhibit-delay-max-seconds
11213 @item handle-power-key
11215 @item handle-suspend-key
11217 @item handle-hibernate-key
11219 @item handle-lid-switch
11221 @item handle-lid-switch-docked
11223 @item power-key-ignore-inhibited?
11225 @item suspend-key-ignore-inhibited?
11227 @item hibernate-key-ignore-inhibited?
11229 @item lid-switch-ignore-inhibited?
11231 @item holdoff-timeout-seconds
11235 @item idle-action-seconds
11237 @item runtime-directory-size-percent
11239 @item runtime-directory-size
11243 @item suspend-state
11244 @code{("mem" "standby" "freeze")}
11247 @item hibernate-state
11249 @item hibernate-mode
11250 @code{("platform" "shutdown")}
11251 @item hybrid-sleep-state
11253 @item hybrid-sleep-mode
11254 @code{("suspend" "platform" "shutdown")}
11258 @deffn {Scheme Procedure} polkit-service @
11259 [#:polkit @var{polkit}]
11260 Return a service that runs the
11261 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11262 management service}, which allows system administrators to grant access to
11263 privileged operations in a structured way. By querying the Polkit service, a
11264 privileged system component can know when it should grant additional
11265 capabilities to ordinary users. For example, an ordinary user can be granted
11266 the capability to suspend the system if the user is logged in locally.
11269 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11270 [#:watts-up-pro? #f] @
11271 [#:poll-batteries? #t] @
11272 [#:ignore-lid? #f] @
11273 [#:use-percentage-for-policy? #f] @
11274 [#:percentage-low 10] @
11275 [#:percentage-critical 3] @
11276 [#:percentage-action 2] @
11277 [#:time-low 1200] @
11278 [#:time-critical 300] @
11279 [#:time-action 120] @
11280 [#:critical-power-action 'hybrid-sleep]
11281 Return a service that runs @uref{http://upower.freedesktop.org/,
11282 @command{upowerd}}, a system-wide monitor for power consumption and battery
11283 levels, with the given configuration settings. It implements the
11284 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11288 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11289 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11290 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11291 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11292 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11295 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11296 Return a service that runs @command{colord}, a system service with a D-Bus
11297 interface to manage the color profiles of input and output devices such as
11298 screens and scanners. It is notably used by the GNOME Color Manager graphical
11299 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11300 site} for more information.
11303 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11304 Return a configuration allowing an application to access GeoClue
11305 location data. @var{name} is the Desktop ID of the application, without
11306 the @code{.desktop} part. If @var{allowed?} is true, the application
11307 will have access to location information by default. The boolean
11308 @var{system?} value indicates whether an application is a system component
11309 or not. Finally @var{users} is a list of UIDs of all users for which
11310 this application is allowed location info access. An empty users list
11311 means that all users are allowed.
11314 @defvr {Scheme Variable} %standard-geoclue-applications
11315 The standard list of well-known GeoClue application configurations,
11316 granting authority to the GNOME date-and-time utility to ask for the
11317 current location in order to set the time zone, and allowing the
11318 IceCat and Epiphany web browsers to request location information.
11319 IceCat and Epiphany both query the user before allowing a web page to
11320 know the user's location.
11323 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11324 [#:whitelist '()] @
11325 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11326 [#:submit-data? #f]
11327 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11328 [#:submission-nick "geoclue"] @
11329 [#:applications %standard-geoclue-applications]
11330 Return a service that runs the GeoClue location service. This service
11331 provides a D-Bus interface to allow applications to request access to a
11332 user's physical location, and optionally to add information to online
11333 location databases. See
11334 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11335 web site} for more information.
11338 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11339 Return a service that runs the @command{bluetoothd} daemon, which manages
11340 all the Bluetooth devices and provides a number of D-Bus interfaces.
11342 Users need to be in the @code{lp} group to access the D-Bus service.
11345 @node Database Services
11346 @subsubsection Database Services
11350 The @code{(gnu services databases)} module provides the following services.
11352 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11353 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11354 [#:port 5432] [#:locale ``en_US.utf8'']
11355 Return a service that runs @var{postgresql}, the PostgreSQL database
11358 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11359 creates a database cluster with @var{locale} as the default
11360 locale, stored in @var{data-directory}. It then listens on @var{port}.
11363 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11364 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11367 The optional @var{config} argument specifies the configuration for
11368 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11371 @deftp {Data Type} mysql-configuration
11372 Data type representing the configuration of @var{mysql-service}.
11375 @item @code{mysql} (default: @var{mariadb})
11376 Package object of the MySQL database server, can be either @var{mariadb}
11379 For MySQL, a temporary root password will be displayed at activation time.
11380 For MariaDB, the root password is empty.
11382 @item @code{port} (default: @code{3306})
11383 TCP port on which the database server listens for incoming connections.
11387 @defvr {Scheme Variable} redis-service-type
11388 This is the service type for the @uref{https://redis.io/, Redis}
11389 key/value store, whose value is a @code{redis-configuration} object.
11392 @deftp {Data Type} redis-configuration
11393 Data type representing the configuration of redis.
11396 @item @code{redis} (default: @code{redis})
11397 The Redis package to use.
11399 @item @code{bind} (default: @code{"127.0.0.1"})
11400 Network interface on which to listen.
11402 @item @code{port} (default: @code{6379})
11403 Port on which to accept connections on, a value of 0 will disable
11404 listening on a TCP socket.
11406 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11407 Directory in which to store the database and related files.
11411 @node Mail Services
11412 @subsubsection Mail Services
11416 The @code{(gnu services mail)} module provides Guix service definitions
11417 for email services: IMAP, POP3, and LMTP servers, as well as mail
11418 transport agents (MTAs). Lots of acronyms! These services are detailed
11419 in the subsections below.
11421 @subsubheading Dovecot Service
11423 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11424 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11427 By default, Dovecot does not need much configuration; the default
11428 configuration object created by @code{(dovecot-configuration)} will
11429 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11430 certificate will be generated for TLS-protected connections, though
11431 Dovecot will also listen on cleartext ports by default. There are a
11432 number of options, though, which mail administrators might need to change,
11433 and as is the case with other services, Guix allows the system
11434 administrator to specify these parameters via a uniform Scheme interface.
11436 For example, to specify that mail is located at @code{maildir~/.mail},
11437 one would instantiate the Dovecot service like this:
11440 (dovecot-service #:config
11441 (dovecot-configuration
11442 (mail-location "maildir:~/.mail")))
11445 The available configuration parameters follow. Each parameter
11446 definition is preceded by its type; for example, @samp{string-list foo}
11447 indicates that the @code{foo} parameter should be specified as a list of
11448 strings. There is also a way to specify the configuration as a string,
11449 if you have an old @code{dovecot.conf} file that you want to port over
11450 from some other system; see the end for more details.
11452 @c The following documentation was initially generated by
11453 @c (generate-documentation) in (gnu services mail). Manually maintained
11454 @c documentation is better, so we shouldn't hesitate to edit below as
11455 @c needed. However if the change you want to make to this documentation
11456 @c can be done in an automated way, it's probably easier to change
11457 @c (generate-documentation) than to make it below and have to deal with
11458 @c the churn as dovecot updates.
11460 Available @code{dovecot-configuration} fields are:
11462 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11463 The dovecot package.
11466 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11467 A list of IPs or hosts where to listen for connections. @samp{*}
11468 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11469 interfaces. If you want to specify non-default ports or anything more
11470 complex, customize the address and port fields of the
11471 @samp{inet-listener} of the specific services you are interested in.
11474 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11475 List of protocols we want to serve. Available protocols include
11476 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11478 Available @code{protocol-configuration} fields are:
11480 @deftypevr {@code{protocol-configuration} parameter} string name
11481 The name of the protocol.
11484 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11485 UNIX socket path to the master authentication server to find users.
11486 This is used by imap (for shared users) and lda.
11487 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11490 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11491 Space separated list of plugins to load.
11494 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11495 Maximum number of IMAP connections allowed for a user from each IP
11496 address. NOTE: The username is compared case-sensitively.
11497 Defaults to @samp{10}.
11502 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11503 List of services to enable. Available services include @samp{imap},
11504 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11507 Available @code{service-configuration} fields are:
11509 @deftypevr {@code{service-configuration} parameter} string kind
11510 The service kind. Valid values include @code{director},
11511 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11512 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11513 @code{tcpwrap}, @code{quota-warning}, or anything else.
11516 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11517 Listeners for the service. A listener is either a
11518 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11519 an @code{inet-listener-configuration}.
11520 Defaults to @samp{()}.
11522 Available @code{unix-listener-configuration} fields are:
11524 @deftypevr {@code{unix-listener-configuration} parameter} string path
11525 Path to the file, relative to @code{base-dir} field. This is also used as
11529 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11530 The access mode for the socket.
11531 Defaults to @samp{"0600"}.
11534 @deftypevr {@code{unix-listener-configuration} parameter} string user
11535 The user to own the socket.
11536 Defaults to @samp{""}.
11539 @deftypevr {@code{unix-listener-configuration} parameter} string group
11540 The group to own the socket.
11541 Defaults to @samp{""}.
11545 Available @code{fifo-listener-configuration} fields are:
11547 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11548 Path to the file, relative to @code{base-dir} field. This is also used as
11552 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11553 The access mode for the socket.
11554 Defaults to @samp{"0600"}.
11557 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11558 The user to own the socket.
11559 Defaults to @samp{""}.
11562 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11563 The group to own the socket.
11564 Defaults to @samp{""}.
11568 Available @code{inet-listener-configuration} fields are:
11570 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11571 The protocol to listen for.
11574 @deftypevr {@code{inet-listener-configuration} parameter} string address
11575 The address on which to listen, or empty for all addresses.
11576 Defaults to @samp{""}.
11579 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11580 The port on which to listen.
11583 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11584 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11586 Defaults to @samp{#t}.
11591 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11592 Number of connections to handle before starting a new process.
11593 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11594 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11595 Defaults to @samp{1}.
11598 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11599 Number of processes to always keep waiting for more connections.
11600 Defaults to @samp{0}.
11603 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11604 If you set @samp{service-count 0}, you probably need to grow
11606 Defaults to @samp{256000000}.
11611 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11612 Dict configuration, as created by the @code{dict-configuration}
11615 Available @code{dict-configuration} fields are:
11617 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11618 A list of key-value pairs that this dict should hold.
11619 Defaults to @samp{()}.
11624 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11625 A list of passdb configurations, each one created by the
11626 @code{passdb-configuration} constructor.
11628 Available @code{passdb-configuration} fields are:
11630 @deftypevr {@code{passdb-configuration} parameter} string driver
11631 The driver that the passdb should use. Valid values include
11632 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11634 Defaults to @samp{"pam"}.
11637 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11638 Space separated list of arguments to the passdb driver.
11639 Defaults to @samp{""}.
11644 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11645 List of userdb configurations, each one created by the
11646 @code{userdb-configuration} constructor.
11648 Available @code{userdb-configuration} fields are:
11650 @deftypevr {@code{userdb-configuration} parameter} string driver
11651 The driver that the userdb should use. Valid values include
11652 @samp{passwd} and @samp{static}.
11653 Defaults to @samp{"passwd"}.
11656 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11657 Space separated list of arguments to the userdb driver.
11658 Defaults to @samp{""}.
11661 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11662 Override fields from passwd.
11663 Defaults to @samp{()}.
11668 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11669 Plug-in configuration, created by the @code{plugin-configuration}
11673 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11674 List of namespaces. Each item in the list is created by the
11675 @code{namespace-configuration} constructor.
11677 Available @code{namespace-configuration} fields are:
11679 @deftypevr {@code{namespace-configuration} parameter} string name
11680 Name for this namespace.
11683 @deftypevr {@code{namespace-configuration} parameter} string type
11684 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11685 Defaults to @samp{"private"}.
11688 @deftypevr {@code{namespace-configuration} parameter} string separator
11689 Hierarchy separator to use. You should use the same separator for
11690 all namespaces or some clients get confused. @samp{/} is usually a good
11691 one. The default however depends on the underlying mail storage
11693 Defaults to @samp{""}.
11696 @deftypevr {@code{namespace-configuration} parameter} string prefix
11697 Prefix required to access this namespace. This needs to be
11698 different for all namespaces. For example @samp{Public/}.
11699 Defaults to @samp{""}.
11702 @deftypevr {@code{namespace-configuration} parameter} string location
11703 Physical location of the mailbox. This is in the same format as
11704 mail_location, which is also the default for it.
11705 Defaults to @samp{""}.
11708 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11709 There can be only one INBOX, and this setting defines which
11711 Defaults to @samp{#f}.
11714 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11715 If namespace is hidden, it's not advertised to clients via NAMESPACE
11716 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11717 useful when converting from another server with different namespaces
11718 which you want to deprecate but still keep working. For example you can
11719 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11721 Defaults to @samp{#f}.
11724 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11725 Show the mailboxes under this namespace with the LIST command. This
11726 makes the namespace visible for clients that do not support the NAMESPACE
11727 extension. The special @code{children} value lists child mailboxes, but
11728 hides the namespace prefix.
11729 Defaults to @samp{#t}.
11732 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11733 Namespace handles its own subscriptions. If set to @code{#f}, the
11734 parent namespace handles them. The empty prefix should always have this
11736 Defaults to @samp{#t}.
11739 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11740 List of predefined mailboxes in this namespace.
11741 Defaults to @samp{()}.
11743 Available @code{mailbox-configuration} fields are:
11745 @deftypevr {@code{mailbox-configuration} parameter} string name
11746 Name for this mailbox.
11749 @deftypevr {@code{mailbox-configuration} parameter} string auto
11750 @samp{create} will automatically create this mailbox.
11751 @samp{subscribe} will both create and subscribe to the mailbox.
11752 Defaults to @samp{"no"}.
11755 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11756 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11757 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11758 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11759 Defaults to @samp{()}.
11766 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11767 Base directory where to store runtime data.
11768 Defaults to @samp{"/var/run/dovecot/"}.
11771 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11772 Greeting message for clients.
11773 Defaults to @samp{"Dovecot ready."}.
11776 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11777 List of trusted network ranges. Connections from these IPs are
11778 allowed to override their IP addresses and ports (for logging and for
11779 authentication checks). @samp{disable-plaintext-auth} is also ignored
11780 for these networks. Typically you would specify your IMAP proxy servers
11782 Defaults to @samp{()}.
11785 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11786 List of login access check sockets (e.g. tcpwrap).
11787 Defaults to @samp{()}.
11790 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11791 Show more verbose process titles (in ps). Currently shows user name
11792 and IP address. Useful for seeing who is actually using the IMAP
11793 processes (e.g. shared mailboxes or if the same uid is used for multiple
11795 Defaults to @samp{#f}.
11798 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11799 Should all processes be killed when Dovecot master process shuts down.
11800 Setting this to @code{#f} means that Dovecot can be upgraded without
11801 forcing existing client connections to close (although that could also
11802 be a problem if the upgrade is e.g. due to a security fix).
11803 Defaults to @samp{#t}.
11806 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11807 If non-zero, run mail commands via this many connections to doveadm
11808 server, instead of running them directly in the same process.
11809 Defaults to @samp{0}.
11812 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11813 UNIX socket or host:port used for connecting to doveadm server.
11814 Defaults to @samp{"doveadm-server"}.
11817 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11818 List of environment variables that are preserved on Dovecot startup
11819 and passed down to all of its child processes. You can also give
11820 key=value pairs to always set specific settings.
11823 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11824 Disable LOGIN command and all other plaintext authentications unless
11825 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11826 matches the local IP (i.e. you're connecting from the same computer),
11827 the connection is considered secure and plaintext authentication is
11828 allowed. See also ssl=required setting.
11829 Defaults to @samp{#t}.
11832 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11833 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11834 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11835 for caching to be used.
11836 Defaults to @samp{0}.
11839 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11840 Time to live for cached data. After TTL expires the cached record
11841 is no longer used, *except* if the main database lookup returns internal
11842 failure. We also try to handle password changes automatically: If
11843 user's previous authentication was successful, but this one wasn't, the
11844 cache isn't used. For now this works only with plaintext
11846 Defaults to @samp{"1 hour"}.
11849 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11850 TTL for negative hits (user not found, password mismatch).
11851 0 disables caching them completely.
11852 Defaults to @samp{"1 hour"}.
11855 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11856 List of realms for SASL authentication mechanisms that need them.
11857 You can leave it empty if you don't want to support multiple realms.
11858 Many clients simply use the first one listed here, so keep the default
11860 Defaults to @samp{()}.
11863 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11864 Default realm/domain to use if none was specified. This is used for
11865 both SASL realms and appending @@domain to username in plaintext
11867 Defaults to @samp{""}.
11870 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11871 List of allowed characters in username. If the user-given username
11872 contains a character not listed in here, the login automatically fails.
11873 This is just an extra check to make sure user can't exploit any
11874 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11875 you want to allow all characters, set this value to empty.
11876 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11879 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11880 Username character translations before it's looked up from
11881 databases. The value contains series of from -> to characters. For
11882 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11883 translated to @samp{@@}.
11884 Defaults to @samp{""}.
11887 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11888 Username formatting before it's looked up from databases. You can
11889 use the standard variables here, e.g. %Lu would lowercase the username,
11890 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11891 change the @samp{@@} into @samp{-AT-}. This translation is done after
11892 @samp{auth-username-translation} changes.
11893 Defaults to @samp{"%Lu"}.
11896 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11897 If you want to allow master users to log in by specifying the master
11898 username within the normal username string (i.e. not using SASL
11899 mechanism's support for it), you can specify the separator character
11900 here. The format is then <username><separator><master username>.
11901 UW-IMAP uses @samp{*} as the separator, so that could be a good
11903 Defaults to @samp{""}.
11906 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11907 Username to use for users logging in with ANONYMOUS SASL
11909 Defaults to @samp{"anonymous"}.
11912 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11913 Maximum number of dovecot-auth worker processes. They're used to
11914 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11915 They're automatically created and destroyed as needed.
11916 Defaults to @samp{30}.
11919 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11920 Host name to use in GSSAPI principal names. The default is to use
11921 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
11922 allow all keytab entries.
11923 Defaults to @samp{""}.
11926 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
11927 Kerberos keytab to use for the GSSAPI mechanism. Will use the
11928 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
11929 need to change the auth service to run as root to be able to read this
11931 Defaults to @samp{""}.
11934 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
11935 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
11936 and @samp{ntlm-auth} helper.
11937 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
11938 Defaults to @samp{#f}.
11941 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
11942 Path for Samba's @samp{ntlm-auth} helper binary.
11943 Defaults to @samp{"/usr/bin/ntlm_auth"}.
11946 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
11947 Time to delay before replying to failed authentications.
11948 Defaults to @samp{"2 secs"}.
11951 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
11952 Require a valid SSL client certificate or the authentication
11954 Defaults to @samp{#f}.
11957 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
11958 Take the username from client's SSL certificate, using
11959 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
11961 Defaults to @samp{#f}.
11964 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
11965 List of wanted authentication mechanisms. Supported mechanisms are:
11966 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
11967 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
11968 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
11969 @samp{disable-plaintext-auth} setting.
11972 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
11973 List of IPs or hostnames to all director servers, including ourself.
11974 Ports can be specified as ip:port. The default port is the same as what
11975 director service's @samp{inet-listener} is using.
11976 Defaults to @samp{()}.
11979 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
11980 List of IPs or hostnames to all backend mail servers. Ranges are
11981 allowed too, like 10.0.0.10-10.0.0.30.
11982 Defaults to @samp{()}.
11985 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
11986 How long to redirect users to a specific server after it no longer
11987 has any connections.
11988 Defaults to @samp{"15 min"}.
11991 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
11992 TCP/IP port that accepts doveadm connections (instead of director
11993 connections) If you enable this, you'll also need to add
11994 @samp{inet-listener} for the port.
11995 Defaults to @samp{0}.
11998 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
11999 How the username is translated before being hashed. Useful values
12000 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12001 are shared within domain.
12002 Defaults to @samp{"%Lu"}.
12005 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12006 Log file to use for error messages. @samp{syslog} logs to syslog,
12007 @samp{/dev/stderr} logs to stderr.
12008 Defaults to @samp{"syslog"}.
12011 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12012 Log file to use for informational messages. Defaults to
12014 Defaults to @samp{""}.
12017 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12018 Log file to use for debug messages. Defaults to
12019 @samp{info-log-path}.
12020 Defaults to @samp{""}.
12023 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12024 Syslog facility to use if you're logging to syslog. Usually if you
12025 don't want to use @samp{mail}, you'll use local0..local7. Also other
12026 standard facilities are supported.
12027 Defaults to @samp{"mail"}.
12030 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12031 Log unsuccessful authentication attempts and the reasons why they
12033 Defaults to @samp{#f}.
12036 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12037 In case of password mismatches, log the attempted password. Valid
12038 values are no, plain and sha1. sha1 can be useful for detecting brute
12039 force password attempts vs. user simply trying the same password over
12040 and over again. You can also truncate the value to n chars by appending
12041 ":n" (e.g. sha1:6).
12042 Defaults to @samp{#f}.
12045 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12046 Even more verbose logging for debugging purposes. Shows for example
12048 Defaults to @samp{#f}.
12051 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12052 In case of password mismatches, log the passwords and used scheme so
12053 the problem can be debugged. Enabling this also enables
12055 Defaults to @samp{#f}.
12058 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12059 Enable mail process debugging. This can help you figure out why
12060 Dovecot isn't finding your mails.
12061 Defaults to @samp{#f}.
12064 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12065 Show protocol level SSL errors.
12066 Defaults to @samp{#f}.
12069 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12070 Prefix for each line written to log file. % codes are in
12071 strftime(3) format.
12072 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12075 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12076 List of elements we want to log. The elements which have a
12077 non-empty variable value are joined together to form a comma-separated
12081 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12082 Login log format. %s contains @samp{login-log-format-elements}
12083 string, %$ contains the data we want to log.
12084 Defaults to @samp{"%$: %s"}.
12087 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12088 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12089 of possible variables you can use.
12090 Defaults to @samp{"\"%s(%u): \""}.
12093 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12094 Format to use for logging mail deliveries. You can use variables:
12097 Delivery status message (e.g. @samp{saved to INBOX})
12109 Defaults to @samp{"msgid=%m: %$"}.
12112 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12113 Location for users' mailboxes. The default is empty, which means
12114 that Dovecot tries to find the mailboxes automatically. This won't work
12115 if the user doesn't yet have any mail, so you should explicitly tell
12116 Dovecot the full location.
12118 If you're using mbox, giving a path to the INBOX
12119 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12120 where the other mailboxes are kept. This is called the "root mail
12121 directory", and it must be the first path given in the
12122 @samp{mail-location} setting.
12124 There are a few special variables you can use, eg.:
12130 user part in user@@domain, same as %u if there's no domain
12132 domain part in user@@domain, empty if there's no domain
12137 See doc/wiki/Variables.txt for full list. Some examples:
12139 @item maildir:~/Maildir
12140 @item mbox:~/mail:INBOX=/var/mail/%u
12141 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12143 Defaults to @samp{""}.
12146 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12147 System user and group used to access mails. If you use multiple,
12148 userdb can override these by returning uid or gid fields. You can use
12149 either numbers or names. <doc/wiki/UserIds.txt>.
12150 Defaults to @samp{""}.
12153 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12155 Defaults to @samp{""}.
12158 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12159 Group to enable temporarily for privileged operations. Currently
12160 this is used only with INBOX when either its initial creation or
12161 dotlocking fails. Typically this is set to "mail" to give access to
12163 Defaults to @samp{""}.
12166 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12167 Grant access to these supplementary groups for mail processes.
12168 Typically these are used to set up access to shared mailboxes. Note
12169 that it may be dangerous to set these if users can create
12170 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12171 could allow a user to delete others' mailboxes, or ln -s
12172 /secret/shared/box ~/mail/mybox would allow reading it).
12173 Defaults to @samp{""}.
12176 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12177 Allow full file system access to clients. There's no access checks
12178 other than what the operating system does for the active UID/GID. It
12179 works with both maildir and mboxes, allowing you to prefix mailboxes
12180 names with e.g. /path/ or ~user/.
12181 Defaults to @samp{#f}.
12184 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12185 Don't use mmap() at all. This is required if you store indexes to
12186 shared file systems (NFS or clustered file system).
12187 Defaults to @samp{#f}.
12190 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12191 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12192 supports @samp{O_EXCL} since version 3, so this should be safe to use
12193 nowadays by default.
12194 Defaults to @samp{#t}.
12197 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12198 When to use fsync() or fdatasync() calls:
12201 Whenever necessary to avoid losing important data
12203 Useful with e.g. NFS when write()s are delayed
12205 Never use it (best performance, but crashes can lose data).
12207 Defaults to @samp{"optimized"}.
12210 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12211 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12212 NFS caches whenever needed. If you're using only a single mail server
12214 Defaults to @samp{#f}.
12217 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12218 Mail index files also exist in NFS. Setting this to yes requires
12219 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12220 Defaults to @samp{#f}.
12223 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12224 Locking method for index files. Alternatives are fcntl, flock and
12225 dotlock. Dotlocking uses some tricks which may create more disk I/O
12226 than other locking methods. NFS users: flock doesn't work, remember to
12227 change @samp{mmap-disable}.
12228 Defaults to @samp{"fcntl"}.
12231 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12232 Directory in which LDA/LMTP temporarily stores incoming mails >128
12234 Defaults to @samp{"/tmp"}.
12237 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12238 Valid UID range for users. This is mostly to make sure that users can't
12239 log in as daemons or other system users. Note that denying root logins is
12240 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12242 Defaults to @samp{500}.
12245 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12247 Defaults to @samp{0}.
12250 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12251 Valid GID range for users. Users having non-valid GID as primary group ID
12252 aren't allowed to log in. If user belongs to supplementary groups with
12253 non-valid GIDs, those groups are not set.
12254 Defaults to @samp{1}.
12257 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12259 Defaults to @samp{0}.
12262 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12263 Maximum allowed length for mail keyword name. It's only forced when
12264 trying to create new keywords.
12265 Defaults to @samp{50}.
12268 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12269 List of directories under which chrooting is allowed for mail
12270 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12271 too). This setting doesn't affect @samp{login-chroot}
12272 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12273 "/./" in home dirs are ignored. WARNING: Never add directories here
12274 which local users can modify, that may lead to root exploit. Usually
12275 this should be done only if you don't allow shell access for users.
12276 <doc/wiki/Chrooting.txt>.
12277 Defaults to @samp{()}.
12280 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12281 Default chroot directory for mail processes. This can be overridden
12282 for specific users in user database by giving /./ in user's home
12283 directory (e.g. /home/./user chroots into /home). Note that usually
12284 there is no real need to do chrooting, Dovecot doesn't allow users to
12285 access files outside their mail directory anyway. If your home
12286 directories are prefixed with the chroot directory, append "/." to
12287 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12288 Defaults to @samp{""}.
12291 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12292 UNIX socket path to master authentication server to find users.
12293 This is used by imap (for shared users) and lda.
12294 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12297 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12298 Directory where to look up mail plugins.
12299 Defaults to @samp{"/usr/lib/dovecot"}.
12302 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12303 List of plugins to load for all services. Plugins specific to IMAP,
12304 LDA, etc. are added to this list in their own .conf files.
12305 Defaults to @samp{()}.
12308 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12309 The minimum number of mails in a mailbox before updates are done to
12310 cache file. This allows optimizing Dovecot's behavior to do less disk
12311 writes at the cost of more disk reads.
12312 Defaults to @samp{0}.
12315 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12316 When IDLE command is running, mailbox is checked once in a while to
12317 see if there are any new mails or other changes. This setting defines
12318 the minimum time to wait between those checks. Dovecot can also use
12319 dnotify, inotify and kqueue to find out immediately when changes
12321 Defaults to @samp{"30 secs"}.
12324 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12325 Save mails with CR+LF instead of plain LF. This makes sending those
12326 mails take less CPU, especially with sendfile() syscall with Linux and
12327 FreeBSD. But it also creates a bit more disk I/O which may just make it
12328 slower. Also note that if other software reads the mboxes/maildirs,
12329 they may handle the extra CRs wrong and cause problems.
12330 Defaults to @samp{#f}.
12333 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12334 By default LIST command returns all entries in maildir beginning
12335 with a dot. Enabling this option makes Dovecot return only entries
12336 which are directories. This is done by stat()ing each entry, so it
12337 causes more disk I/O.
12338 (For systems setting struct @samp{dirent->d_type} this check is free
12339 and it's done always regardless of this setting).
12340 Defaults to @samp{#f}.
12343 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12344 When copying a message, do it with hard links whenever possible.
12345 This makes the performance much better, and it's unlikely to have any
12347 Defaults to @samp{#t}.
12350 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12351 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12352 directory only when its mtime changes unexpectedly or when we can't find
12353 the mail otherwise.
12354 Defaults to @samp{#f}.
12357 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12358 Which locking methods to use for locking mbox. There are four
12363 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12364 solution. If you want to use /var/mail/ like directory, the users will
12365 need write access to that directory.
12367 Same as dotlock, but if it fails because of permissions or because there
12368 isn't enough disk space, just skip it.
12370 Use this if possible. Works with NFS too if lockd is used.
12372 May not exist in all systems. Doesn't work with NFS.
12374 May not exist in all systems. Doesn't work with NFS.
12377 You can use multiple locking methods; if you do the order they're declared
12378 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12379 locking methods as well. Some operating systems don't allow using some of
12380 them simultaneously.
12383 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12387 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12388 Maximum time to wait for lock (all of them) before aborting.
12389 Defaults to @samp{"5 mins"}.
12392 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12393 If dotlock exists but the mailbox isn't modified in any way,
12394 override the lock file after this much time.
12395 Defaults to @samp{"2 mins"}.
12398 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12399 When mbox changes unexpectedly we have to fully read it to find out
12400 what changed. If the mbox is large this can take a long time. Since
12401 the change is usually just a newly appended mail, it'd be faster to
12402 simply read the new mails. If this setting is enabled, Dovecot does
12403 this but still safely fallbacks to re-reading the whole mbox file
12404 whenever something in mbox isn't how it's expected to be. The only real
12405 downside to this setting is that if some other MUA changes message
12406 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12407 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12408 Defaults to @samp{#t}.
12411 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12412 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12413 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12414 @samp{mbox-dirty-syncs} is ignored.
12415 Defaults to @samp{#f}.
12418 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12419 Delay writing mbox headers until doing a full write sync (EXPUNGE
12420 and CHECK commands and when closing the mailbox). This is especially
12421 useful for POP3 where clients often delete all mails. The downside is
12422 that our changes aren't immediately visible to other MUAs.
12423 Defaults to @samp{#t}.
12426 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12427 If mbox size is smaller than this (e.g. 100k), don't write index
12428 files. If an index file already exists it's still read, just not
12430 Defaults to @samp{0}.
12433 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12434 Maximum dbox file size until it's rotated.
12435 Defaults to @samp{2000000}.
12438 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12439 Maximum dbox file age until it's rotated. Typically in days. Day
12440 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12442 Defaults to @samp{"1d"}.
12445 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12446 When creating new mdbox files, immediately preallocate their size to
12447 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12448 with some file systems (ext4, xfs).
12449 Defaults to @samp{#f}.
12452 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12453 sdbox and mdbox support saving mail attachments to external files,
12454 which also allows single instance storage for them. Other backends
12455 don't support this for now.
12457 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12459 Directory root where to store mail attachments. Disabled, if empty.
12460 Defaults to @samp{""}.
12463 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12464 Attachments smaller than this aren't saved externally. It's also
12465 possible to write a plugin to disable saving specific attachments
12467 Defaults to @samp{128000}.
12470 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12471 File system backend to use for saving attachments:
12474 No SiS done by Dovecot (but this might help FS's own deduplication)
12476 SiS with immediate byte-by-byte comparison during saving
12477 @item sis-queue posix
12478 SiS with delayed comparison and deduplication.
12480 Defaults to @samp{"sis posix"}.
12483 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12484 Hash format to use in attachment filenames. You can add any text and
12485 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12486 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12487 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12488 Defaults to @samp{"%@{sha1@}"}.
12491 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12493 Defaults to @samp{100}.
12496 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12498 Defaults to @samp{1000}.
12501 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12502 Default VSZ (virtual memory size) limit for service processes.
12503 This is mainly intended to catch and kill processes that leak memory
12504 before they eat up everything.
12505 Defaults to @samp{256000000}.
12508 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12509 Login user is internally used by login processes. This is the most
12510 untrusted user in Dovecot system. It shouldn't have access to anything
12512 Defaults to @samp{"dovenull"}.
12515 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12516 Internal user is used by unprivileged processes. It should be
12517 separate from login user, so that login processes can't disturb other
12519 Defaults to @samp{"dovecot"}.
12522 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12523 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12524 Defaults to @samp{"required"}.
12527 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12528 PEM encoded X.509 SSL/TLS certificate (public key).
12529 Defaults to @samp{"</etc/dovecot/default.pem"}.
12532 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12533 PEM encoded SSL/TLS private key. The key is opened before
12534 dropping root privileges, so keep the key file unreadable by anyone but
12536 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12539 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12540 If key file is password protected, give the password here.
12541 Alternatively give it when starting dovecot with -p parameter. Since
12542 this file is often world-readable, you may want to place this setting
12543 instead to a different.
12544 Defaults to @samp{""}.
12547 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12548 PEM encoded trusted certificate authority. Set this only if you
12549 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12550 contain the CA certificate(s) followed by the matching
12551 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12552 Defaults to @samp{""}.
12555 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12556 Require that CRL check succeeds for client certificates.
12557 Defaults to @samp{#t}.
12560 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12561 Request client to send a certificate. If you also want to require
12562 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12563 Defaults to @samp{#f}.
12566 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12567 Which field from certificate to use for username. commonName and
12568 x500UniqueIdentifier are the usual choices. You'll also need to set
12569 @samp{auth-ssl-username-from-cert? #t}.
12570 Defaults to @samp{"commonName"}.
12573 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12574 How often to regenerate the SSL parameters file. Generation is
12575 quite CPU intensive operation. The value is in hours, 0 disables
12576 regeneration entirely.
12577 Defaults to @samp{168}.
12580 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12581 SSL protocols to use.
12582 Defaults to @samp{"!SSLv2"}.
12585 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12586 SSL ciphers to use.
12587 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12590 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12591 SSL crypto device to use, for valid values run "openssl engine".
12592 Defaults to @samp{""}.
12595 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12596 Address to use when sending rejection mails.
12597 %d expands to recipient domain.
12598 Defaults to @samp{"postmaster@@%d"}.
12601 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12602 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12603 and in LMTP replies. Default is the system's real hostname@@domain.
12604 Defaults to @samp{""}.
12607 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12608 If user is over quota, return with temporary failure instead of
12610 Defaults to @samp{#f}.
12613 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12614 Binary to use for sending mails.
12615 Defaults to @samp{"/usr/sbin/sendmail"}.
12618 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12619 If non-empty, send mails via this SMTP host[:port] instead of
12621 Defaults to @samp{""}.
12624 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12625 Subject: header to use for rejection mails. You can use the same
12626 variables as for @samp{rejection-reason} below.
12627 Defaults to @samp{"Rejected: %s"}.
12630 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12631 Human readable error message for rejection mails. You can use
12644 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12647 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12648 Delimiter character between local-part and detail in email
12650 Defaults to @samp{"+"}.
12653 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12654 Header where the original recipient address (SMTP's RCPT TO:
12655 address) is taken from if not available elsewhere. With dovecot-lda -a
12656 parameter overrides this. A commonly used header for this is
12658 Defaults to @samp{""}.
12661 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12662 Should saving a mail to a nonexistent mailbox automatically create
12664 Defaults to @samp{#f}.
12667 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12668 Should automatically created mailboxes be also automatically
12670 Defaults to @samp{#f}.
12673 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12674 Maximum IMAP command line length. Some clients generate very long
12675 command lines with huge mailboxes, so you may need to raise this if you
12676 get "Too long argument" or "IMAP command line too large" errors
12678 Defaults to @samp{64000}.
12681 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12682 IMAP logout format string:
12685 total number of bytes read from client
12687 total number of bytes sent to client.
12689 Defaults to @samp{"in=%i out=%o"}.
12692 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12693 Override the IMAP CAPABILITY response. If the value begins with '+',
12694 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12695 Defaults to @samp{""}.
12698 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12699 How long to wait between "OK Still here" notifications when client
12701 Defaults to @samp{"2 mins"}.
12704 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12705 ID field names and values to send to clients. Using * as the value
12706 makes Dovecot use the default value. The following fields have default
12707 values currently: name, version, os, os-version, support-url,
12709 Defaults to @samp{""}.
12712 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12713 ID fields sent by client to log. * means everything.
12714 Defaults to @samp{""}.
12717 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12718 Workarounds for various client bugs:
12721 @item delay-newmail
12722 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12723 CHECK commands. Some clients ignore them otherwise, for example OSX
12724 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12725 may show user "Message no longer in server" errors. Note that OE6
12726 still breaks even with this workaround if synchronization is set to
12729 @item tb-extra-mailbox-sep
12730 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12731 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12732 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12734 @item tb-lsub-flags
12735 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12736 This makes Thunderbird realize they aren't selectable and show them
12737 greyed out, instead of only later giving "not selectable" popup error.
12739 Defaults to @samp{()}.
12742 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12743 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12744 Defaults to @samp{""}.
12748 Whew! Lots of configuration options. The nice thing about it though is
12749 that GuixSD has a complete interface to Dovecot's configuration
12750 language. This allows not only a nice way to declare configurations,
12751 but also offers reflective capabilities as well: users can write code to
12752 inspect and transform configurations from within Scheme.
12754 However, it could be that you just want to get a @code{dovecot.conf} up
12755 and running. In that case, you can pass an
12756 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12757 @code{dovecot-service}. As its name indicates, an opaque configuration
12758 does not have easy reflective capabilities.
12760 Available @code{opaque-dovecot-configuration} fields are:
12762 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12763 The dovecot package.
12766 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12767 The contents of the @code{dovecot.conf}, as a string.
12770 For example, if your @code{dovecot.conf} is just the empty string, you
12771 could instantiate a dovecot service like this:
12774 (dovecot-service #:config
12775 (opaque-dovecot-configuration
12779 @subsubheading OpenSMTPD Service
12781 @deffn {Scheme Variable} opensmtpd-service-type
12782 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12783 service, whose value should be an @code{opensmtpd-configuration} object
12784 as in this example:
12787 (service opensmtpd-service-type
12788 (opensmtpd-configuration
12789 (config-file (local-file "./my-smtpd.conf"))))
12793 @deftp {Data Type} opensmtpd-configuration
12794 Data type representing the configuration of opensmtpd.
12797 @item @code{package} (default: @var{opensmtpd})
12798 Package object of the OpenSMTPD SMTP server.
12800 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12801 File-like object of the OpenSMTPD configuration file to use. By default
12802 it listens on the loopback network interface, and allows for mail from
12803 users and daemons on the local machine, as well as permitting email to
12804 remote servers. Run @command{man smtpd.conf} for more information.
12809 @subsubheading Exim Service
12811 @cindex mail transfer agent (MTA)
12812 @cindex MTA (mail transfer agent)
12815 @deffn {Scheme Variable} exim-service-type
12816 This is the type of the @uref{https://exim.org, Exim} mail transfer
12817 agent (MTA), whose value should be an @code{exim-configuration} object
12818 as in this example:
12821 (service exim-service-type
12822 (exim-configuration
12823 (config-file (local-file "./my-exim.conf"))))
12827 In order to use an @code{exim-service-type} service you must also have a
12828 @code{mail-aliases-service-type} service present in your
12829 @code{operating-system} (even if it has no aliases).
12831 @deftp {Data Type} exim-configuration
12832 Data type representing the configuration of exim.
12835 @item @code{package} (default: @var{exim})
12836 Package object of the Exim server.
12838 @item @code{config-file} (default: @code{#f})
12839 File-like object of the Exim configuration file to use. If its value is
12840 @code{#f} then use the default configuration file from the package
12841 provided in @code{package}. The resulting configuration file is loaded
12842 after setting the @code{exim_user} and @code{exim_group} configuration
12848 @subsubheading Mail Aliases Service
12850 @cindex email aliases
12851 @cindex aliases, for email addresses
12853 @deffn {Scheme Variable} mail-aliases-service-type
12854 This is the type of the service which provides @code{/etc/aliases},
12855 specifying how to deliver mail to users on this system.
12858 (service mail-aliases-service-type
12859 '(("postmaster" "bob")
12860 ("bob" "bob@@example.com" "bob@@example2.com")))
12864 The configuration for a @code{mail-aliases-service-type} service is an
12865 association list denoting how to deliver mail that comes to this
12866 system. Each entry is of the form @code{(alias addresses ...)}, with
12867 @code{alias} specifying the local alias and @code{addresses} specifying
12868 where to deliver this user's mail.
12870 The aliases aren't required to exist as users on the local system. In
12871 the above example, there doesn't need to be a @code{postmaster} entry in
12872 the @code{operating-system}'s @code{user-accounts} in order to deliver
12873 the @code{postmaster} mail to @code{bob} (which subsequently would
12874 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
12876 @node Messaging Services
12877 @subsubsection Messaging Services
12882 The @code{(gnu services messaging)} module provides Guix service
12883 definitions for messaging services: currently only Prosody is supported.
12885 @subsubheading Prosody Service
12887 @deffn {Scheme Variable} prosody-service-type
12888 This is the type for the @uref{http://prosody.im, Prosody XMPP
12889 communication server}. Its value must be a @code{prosody-configuration}
12890 record as in this example:
12893 (service prosody-service-type
12894 (prosody-configuration
12895 (modules-enabled (cons "groups" %default-modules-enabled))
12898 (int-component-configuration
12899 (hostname "conference.example.net")
12901 (mod-muc (mod-muc-configuration)))))
12904 (virtualhost-configuration
12905 (domain "example.net"))))))
12908 See below for details about @code{prosody-configuration}.
12912 By default, Prosody does not need much configuration. Only one
12913 @code{virtualhosts} field is needed: it specifies the domain you wish
12916 Prosodyctl will help you generate X.509 certificates and keys:
12919 prosodyctl cert request example.net
12922 The available configuration parameters follow. Each parameter
12923 definition is preceded by its type; for example, @samp{string-list foo}
12924 indicates that the @code{foo} parameter should be specified as a list of
12925 strings. Types starting with @code{maybe-} denote parameters that won't
12926 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
12928 There is also a way to specify the configuration as a string, if you
12929 have an old @code{prosody.cfg.lua} file that you want to port over from
12930 some other system; see the end for more details.
12932 @c The following documentation was initially generated by
12933 @c (generate-documentation) in (gnu services messaging). Manually maintained
12934 @c documentation is better, so we shouldn't hesitate to edit below as
12935 @c needed. However if the change you want to make to this documentation
12936 @c can be done in an automated way, it's probably easier to change
12937 @c (generate-documentation) than to make it below and have to deal with
12938 @c the churn as Prosody updates.
12940 Available @code{prosody-configuration} fields are:
12942 @deftypevr {@code{prosody-configuration} parameter} package prosody
12943 The Prosody package.
12946 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
12947 Location of the Prosody data storage directory. See
12948 @url{http://prosody.im/doc/configure}.
12949 Defaults to @samp{"/var/lib/prosody"}.
12952 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
12953 Additional plugin directories. They are searched in all the specified
12954 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
12955 Defaults to @samp{()}.
12958 @deftypevr {@code{prosody-configuration} parameter} string-list admins
12959 This is a list of accounts that are admins for the server. Note that you
12960 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
12961 @url{http://prosody.im/doc/creating_accounts}.
12962 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
12963 Defaults to @samp{()}.
12966 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
12967 Enable use of libevent for better performance under high load. See
12968 @url{http://prosody.im/doc/libevent}.
12969 Defaults to @samp{#f}.
12972 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
12973 This is the list of modules Prosody will load on startup. It looks for
12974 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
12975 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
12976 Defaults to @samp{%default-modules-enabled}.
12979 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
12980 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
12981 should you want to disable them then add them to this list.
12982 Defaults to @samp{()}.
12985 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
12986 Path to a text file where the shared groups are defined. If this path is
12987 empty then @samp{mod_groups} does nothing. See
12988 @url{http://prosody.im/doc/modules/mod_groups}.
12989 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
12992 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
12993 Disable account creation by default, for security. See
12994 @url{http://prosody.im/doc/creating_accounts}.
12995 Defaults to @samp{#f}.
12998 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
12999 These are the SSL/TLS-related settings. Most of them are disabled so to
13000 use Prosody's defaults. If you do not completely understand these options, do
13001 not add them to your config, it is easy to lower the security of your server
13002 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13004 Available @code{ssl-configuration} fields are:
13006 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13007 This determines what handshake to use.
13010 @deftypevr {@code{ssl-configuration} parameter} file-name key
13011 Path to your private key file, relative to @code{/etc/prosody}.
13012 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13015 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13016 Path to your certificate file, relative to @code{/etc/prosody}.
13017 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13020 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13021 Path to directory containing root certificates that you wish Prosody to
13022 trust when verifying the certificates of remote servers.
13023 Defaults to @samp{"/etc/ssl/certs"}.
13026 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13027 Path to a file containing root certificates that you wish Prosody to trust.
13028 Similar to @code{capath} but with all certificates concatenated together.
13031 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13032 A list of verification options (these mostly map to OpenSSL's
13033 @code{set_verify()} flags).
13036 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13037 A list of general options relating to SSL/TLS. These map to OpenSSL's
13038 @code{set_options()}. For a full list of options available in LuaSec, see the
13042 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13043 How long a chain of certificate authorities to check when looking for a
13044 trusted root certificate.
13047 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13048 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13049 clients, and in what order.
13052 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13053 A path to a file containing parameters for Diffie-Hellman key exchange. You
13054 can create such a file with:
13055 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13058 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13059 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13060 @samp{"secp384r1"}.
13063 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13064 A list of "extra" verification options.
13067 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13068 Password for encrypted private keys.
13073 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13074 Whether to force all client-to-server connections to be encrypted or not.
13075 See @url{http://prosody.im/doc/modules/mod_tls}.
13076 Defaults to @samp{#f}.
13079 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13080 Whether to force all server-to-server connections to be encrypted or not.
13081 See @url{http://prosody.im/doc/modules/mod_tls}.
13082 Defaults to @samp{#f}.
13085 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13086 Whether to require encryption and certificate authentication. This
13087 provides ideal security, but requires servers you communicate with to support
13088 encryption AND present valid, trusted certificates. See
13089 @url{http://prosody.im/doc/s2s#security}.
13090 Defaults to @samp{#f}.
13093 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13094 Many servers don't support encryption or have invalid or self-signed
13095 certificates. You can list domains here that will not be required to
13096 authenticate using certificates. They will be authenticated using DNS. See
13097 @url{http://prosody.im/doc/s2s#security}.
13098 Defaults to @samp{()}.
13101 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13102 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13103 valid certificates for some domains by specifying a list here. See
13104 @url{http://prosody.im/doc/s2s#security}.
13105 Defaults to @samp{()}.
13108 @deftypevr {@code{prosody-configuration} parameter} string authentication
13109 Select the authentication backend to use. The default provider stores
13110 passwords in plaintext and uses Prosody's configured data storage to store the
13111 authentication data. If you do not trust your server please see
13112 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13113 about using the hashed backend. See also
13114 @url{http://prosody.im/doc/authentication}
13115 Defaults to @samp{"internal_plain"}.
13118 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13119 Set logging options. Advanced logging configuration is not yet supported
13120 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13121 Defaults to @samp{"*syslog"}.
13124 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13125 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13126 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13129 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13130 A host in Prosody is a domain on which user accounts can be created. For
13131 example if you want your users to have addresses like
13132 @samp{"john.smith@@example.com"} then you need to add a host
13133 @samp{"example.com"}. All options in this list will apply only to this host.
13135 Note: the name "virtual" host is used in configuration to avoid confusion with
13136 the actual physical host that Prosody is installed on. A single Prosody
13137 instance can serve many domains, each one defined as a VirtualHost entry in
13138 Prosody's configuration. Conversely a server that hosts a single domain would
13139 have just one VirtualHost entry.
13141 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13143 Available @code{virtualhost-configuration} fields are:
13145 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:
13146 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13147 Domain you wish Prosody to serve.
13152 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13153 Components are extra services on a server which are available to clients,
13154 usually on a subdomain of the main server (such as
13155 @samp{"mycomponent.example.com"}). Example components might be chatroom
13156 servers, user directories, or gateways to other protocols.
13158 Internal components are implemented with Prosody-specific plugins. To add an
13159 internal component, you simply fill the hostname field, and the plugin you wish
13160 to use for the component.
13162 See @url{http://prosody.im/doc/components}.
13163 Defaults to @samp{()}.
13165 Available @code{int-component-configuration} fields are:
13167 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:
13168 @deftypevr {@code{int-component-configuration} parameter} string hostname
13169 Hostname of the component.
13172 @deftypevr {@code{int-component-configuration} parameter} string plugin
13173 Plugin you wish to use for the component.
13176 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13177 Multi-user chat (MUC) is Prosody's module for allowing you to create
13178 hosted chatrooms/conferences for XMPP users.
13180 General information on setting up and using multi-user chatrooms can be found
13181 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13182 which you should read if you are new to XMPP chatrooms.
13184 See also @url{http://prosody.im/doc/modules/mod_muc}.
13186 Available @code{mod-muc-configuration} fields are:
13188 @deftypevr {@code{mod-muc-configuration} parameter} string name
13189 The name to return in service discovery responses.
13190 Defaults to @samp{"Prosody Chatrooms"}.
13193 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13194 If @samp{#t}, this will only allow admins to create new chatrooms.
13195 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13196 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13197 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13198 restricts to service administrators only.
13199 Defaults to @samp{#f}.
13202 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13203 Maximum number of history messages that will be sent to the member that has
13204 just joined the room.
13205 Defaults to @samp{20}.
13212 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13213 External components use XEP-0114, which most standalone components
13214 support. To add an external component, you simply fill the hostname field. See
13215 @url{http://prosody.im/doc/components}.
13216 Defaults to @samp{()}.
13218 Available @code{ext-component-configuration} fields are:
13220 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:
13221 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13222 Password which the component will use to log in.
13225 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13226 Hostname of the component.
13231 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13232 Port(s) Prosody listens on for component connections.
13235 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13236 Interface Prosody listens on for component connections.
13237 Defaults to @samp{"127.0.0.1"}.
13240 It could be that you just want to get a @code{prosody.cfg.lua}
13241 up and running. In that case, you can pass an
13242 @code{opaque-prosody-configuration} record as the value of
13243 @code{prosody-service-type}. As its name indicates, an opaque configuration
13244 does not have easy reflective capabilities.
13245 Available @code{opaque-prosody-configuration} fields are:
13247 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13248 The prosody package.
13251 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13252 The contents of the @code{prosody.cfg.lua} to use.
13255 For example, if your @code{prosody.cfg.lua} is just the empty
13256 string, you could instantiate a prosody service like this:
13259 (service prosody-service-type
13260 (opaque-prosody-configuration
13261 (prosody.cfg.lua "")))
13264 @node Kerberos Services
13265 @subsubsection Kerberos Services
13268 The @code{(gnu services kerberos)} module provides services relating to
13269 the authentication protocol @dfn{Kerberos}.
13271 @subsubheading Krb5 Service
13273 Programs using a Kerberos client library normally
13274 expect a configuration file in @file{/etc/krb5.conf}.
13275 This service generates such a file from a definition provided in the
13276 operating system declaration.
13277 It does not cause any daemon to be started.
13279 No ``keytab'' files are provided by this service---you must explicitly create them.
13280 This service is known to work with the MIT client library, @code{mit-krb5}.
13281 Other implementations have not been tested.
13283 @defvr {Scheme Variable} krb5-service-type
13284 A service type for Kerberos 5 clients.
13288 Here is an example of its use:
13290 (service krb5-service-type
13291 (krb5-configuration
13292 (default-realm "EXAMPLE.COM")
13293 (allow-weak-crypto? #t)
13296 (name "EXAMPLE.COM")
13297 (admin-server "groucho.example.com")
13298 (kdc "karl.example.com"))
13301 (admin-server "kerb-admin.argrx.edu")
13302 (kdc "keys.argrx.edu"))))))
13306 This example provides a Kerberos@tie{}5 client configuration which:
13308 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13309 of which have distinct administration servers and key distribution centers;
13310 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13311 specified by clients;
13312 @item Accepts services which only support encryption types known to be weak.
13315 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13316 Only the most commonly used ones are described here.
13317 For a full list, and more detailed explanation of each, see the MIT
13318 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13322 @deftp {Data Type} krb5-realm
13323 @cindex realm, kerberos
13326 This field is a string identifying the name of the realm.
13327 A common convention is to use the fully qualified DNS name of your organization,
13328 converted to upper case.
13330 @item @code{admin-server}
13331 This field is a string identifying the host where the administration server is
13335 This field is a string identifying the key distribution center
13340 @deftp {Data Type} krb5-configuration
13343 @item @code{allow-weak-crypto?} (default: @code{#f})
13344 If this flag is @code{#t} then services which only offer encryption algorithms
13345 known to be weak will be accepted.
13347 @item @code{default-realm} (default: @code{#f})
13348 This field should be a string identifying the default Kerberos
13349 realm for the client.
13350 You should set this field to the name of your Kerberos realm.
13351 If this value is @code{#f}
13352 then a realm must be specified with every Kerberos principal when invoking programs
13353 such as @command{kinit}.
13355 @item @code{realms}
13356 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13358 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13364 @subsubheading PAM krb5 Service
13367 The @code{pam-krb5} service allows for login authentication and password
13368 management via Kerberos.
13369 You will need this service if you want PAM enabled applications to authenticate
13370 users using Kerberos.
13372 @defvr {Scheme Variable} pam-krb5-service-type
13373 A service type for the Kerberos 5 PAM module.
13376 @deftp {Data Type} pam-krb5-configuration
13377 Data type representing the configuration of the Kerberos 5 PAM module
13378 This type has the following parameters:
13380 @item @code{pam-krb5} (default: @code{pam-krb5})
13381 The pam-krb5 package to use.
13383 @item @code{minimum-uid} (default: @code{1000})
13384 The smallest user ID for which Kerberos authentications should be attempted.
13385 Local accounts with lower values will silently fail to authenticate.
13391 @subsubsection Web Services
13396 The @code{(gnu services web)} module provides the following service:
13398 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13399 [#:log-directory ``/var/log/nginx''] @
13400 [#:run-directory ``/var/run/nginx''] @
13401 [#:server-list '()] @
13402 [#:upstream-list '()] @
13403 [#:config-file @code{#f}]
13405 Return a service that runs @var{nginx}, the nginx web server.
13407 The nginx daemon loads its runtime configuration from @var{config-file}.
13408 Log files are written to @var{log-directory} and temporary runtime data
13409 files are written to @var{run-directory}. For proper operation, these
13410 arguments should match what is in @var{config-file} to ensure that the
13411 directories are created when the service is activated.
13413 As an alternative to using a @var{config-file}, @var{server-list} can be
13414 used to specify the list of @dfn{server blocks} required on the host and
13415 @var{upstream-list} can be used to specify a list of @dfn{upstream
13416 blocks} to configure. For this to work, use the default value for
13419 At startup, @command{nginx} has not yet read its configuration file, so it
13420 uses a default file to log error messages. If it fails to load its
13421 configuration file, that is where error messages are logged. After the
13422 configuration file is loaded, the default error log file changes as per
13423 configuration. In our case, startup error messages can be found in
13424 @file{/var/run/nginx/logs/error.log}, and after configuration in
13425 @file{/var/log/nginx/error.log}. The second location can be changed with the
13426 @var{log-directory} configuration option.
13430 @deffn {Scheme Variable} nginx-service-type
13431 This is type for the nginx web server.
13433 This service can be extended to add server blocks in addition to the
13434 default one, as in this example:
13437 (simple-service 'my-extra-server nginx-service-type
13438 (list (nginx-server-configuration
13440 (root "/srv/http/extra-website"))))
13444 @deftp {Data Type} nginx-server-configuration
13445 Data type representing the configuration of an nginx server block.
13446 This type has the following parameters:
13449 @item @code{http-port} (default: @code{80})
13450 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13451 nginx should not listen for HTTP (non secure) connection for this
13452 @dfn{server block}.
13454 @item @code{https-port} (default: @code{443})
13455 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13456 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13458 Note that nginx can listen for HTTP and HTTPS connections in the same
13459 @dfn{server block}.
13461 @item @code{server-name} (default: @code{(list 'default)})
13462 A list of server names this server represents. @code{'default} represents the
13463 default server for connections matching no other server.
13465 @item @code{root} (default: @code{"/srv/http"})
13466 Root of the website nginx will serve.
13468 @item @code{locations} (default: @code{'()})
13469 A list of @dfn{nginx-location-configuration} or
13470 @dfn{nginx-named-location-configuration} records to use within this
13473 @item @code{index} (default: @code{(list "index.html")})
13474 Index files to look for when clients ask for a directory. If it cannot be found,
13475 Nginx will send the list of files in the directory.
13477 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13478 Where to find the certificate for secure connections. Set it to @code{#f} if
13479 you don't have a certificate or you don't want to use HTTPS.
13481 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13482 Where to find the private key for secure connections. Set it to @code{#f} if
13483 you don't have a key or you don't want to use HTTPS.
13485 @item @code{server-tokens?} (default: @code{#f})
13486 Whether the server should add its configuration to response.
13492 @subsubsection VPN Services
13493 @cindex VPN (virtual private network)
13494 @cindex virtual private network (VPN)
13496 The @code{(gnu services vpn)} module provides services related to
13497 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
13498 your machine to connect to a VPN, and a @emph{servire} service for your machine
13499 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
13501 @deffn {Scheme Procedure} openvpn-client-service @
13502 [#:config (openvpn-client-configuration)]
13504 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
13507 @deffn {Scheme Procedure} openvpn-server-service @
13508 [#:config (openvpn-server-configuration)]
13510 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
13512 Both can be run simultaneously.
13515 @c %automatically generated documentation
13517 Available @code{openvpn-client-configuration} fields are:
13519 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
13520 The OpenVPN package.
13524 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
13525 The OpenVPN pid file.
13527 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13531 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
13532 The protocol (UDP or TCP) used to open a channel between clients and
13535 Defaults to @samp{udp}.
13539 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
13540 The device type used to represent the VPN connection.
13542 Defaults to @samp{tun}.
13546 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
13547 The certificate authority to check connections against.
13549 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13553 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
13554 The certificate of the machine the daemon is running on. It should be
13555 signed by the authority given in @code{ca}.
13557 Defaults to @samp{"/etc/openvpn/client.crt"}.
13561 @deftypevr {@code{openvpn-client-configuration} parameter} string key
13562 The key of the machine the daemon is running on. It must be the key whose
13563 certificate is @code{cert}.
13565 Defaults to @samp{"/etc/openvpn/client.key"}.
13569 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
13570 Whether to use the lzo compression algorithm.
13572 Defaults to @samp{#t}.
13576 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
13577 Don't re-read key files across SIGUSR1 or --ping-restart.
13579 Defaults to @samp{#t}.
13583 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
13584 Don't close and reopen TUN/TAP device or run up/down scripts across
13585 SIGUSR1 or --ping-restart restarts.
13587 Defaults to @samp{#t}.
13591 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
13594 Defaults to @samp{3}.
13598 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
13599 Add an additional layer of HMAC authentication on top of the TLS control
13600 channel to protect against DoS attacks.
13602 Defaults to @samp{#f}.
13606 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
13607 Whether to check the server certificate has server usage extension.
13609 Defaults to @samp{#t}.
13613 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
13614 Bind to a specific local port number.
13616 Defaults to @samp{#f}.
13620 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
13621 Retry resolving server address.
13623 Defaults to @samp{#t}.
13627 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
13628 A list of remote servers to connect to.
13630 Defaults to @samp{()}.
13632 Available @code{openvpn-remote-configuration} fields are:
13634 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
13637 Defaults to @samp{"my-server"}.
13641 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
13642 Port number the server listens to.
13644 Defaults to @samp{1194}.
13649 @c %end of automatic openvpn-client documentation
13651 @c %automatically generated documentation
13653 Available @code{openvpn-server-configuration} fields are:
13655 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
13656 The OpenVPN package.
13660 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
13661 The OpenVPN pid file.
13663 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13667 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
13668 The protocol (UDP or TCP) used to open a channel between clients and
13671 Defaults to @samp{udp}.
13675 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
13676 The device type used to represent the VPN connection.
13678 Defaults to @samp{tun}.
13682 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
13683 The certificate authority to check connections against.
13685 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13689 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
13690 The certificate of the machine the daemon is running on. It should be
13691 signed by the authority given in @code{ca}.
13693 Defaults to @samp{"/etc/openvpn/client.crt"}.
13697 @deftypevr {@code{openvpn-server-configuration} parameter} string key
13698 The key of the machine the daemon is running on. It must be the key whose
13699 certificate is @code{cert}.
13701 Defaults to @samp{"/etc/openvpn/client.key"}.
13705 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
13706 Whether to use the lzo compression algorithm.
13708 Defaults to @samp{#t}.
13712 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
13713 Don't re-read key files across SIGUSR1 or --ping-restart.
13715 Defaults to @samp{#t}.
13719 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
13720 Don't close and reopen TUN/TAP device or run up/down scripts across
13721 SIGUSR1 or --ping-restart restarts.
13723 Defaults to @samp{#t}.
13727 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
13730 Defaults to @samp{3}.
13734 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
13735 Add an additional layer of HMAC authentication on top of the TLS control
13736 channel to protect against DoS attacks.
13738 Defaults to @samp{#f}.
13742 @deftypevr {@code{openvpn-server-configuration} parameter} number port
13743 Specifies the port number on which the server listens.
13745 Defaults to @samp{1194}.
13749 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
13750 An ip and mask specifying the subnet inside the virtual network.
13752 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
13756 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
13757 A CIDR notation specifying the IPv6 subnet inside the virtual network.
13759 Defaults to @samp{#f}.
13763 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
13764 The Diffie-Hellman parameters file.
13766 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
13770 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
13771 The file that records client IPs.
13773 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
13777 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
13778 When true, the server will act as a gateway for its clients.
13780 Defaults to @samp{#f}.
13784 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
13785 When true, clients are allowed to talk to each other inside the VPN.
13787 Defaults to @samp{#f}.
13791 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
13792 Causes ping-like messages to be sent back and forth over the link so
13793 that each side knows when the other side has gone down. @code{keepalive}
13794 requires a pair. The first element is the period of the ping sending,
13795 and the second element is the timeout before considering the other side
13800 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
13801 The maximum number of clients.
13803 Defaults to @samp{100}.
13807 @deftypevr {@code{openvpn-server-configuration} parameter} string status
13808 The status file. This file shows a small report on current connection.
13809 It is truncated and rewritten every minute.
13811 Defaults to @samp{"/var/run/openvpn/status"}.
13815 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
13816 The list of configuration for some clients.
13818 Defaults to @samp{()}.
13820 Available @code{openvpn-ccd-configuration} fields are:
13822 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
13825 Defaults to @samp{"client"}.
13829 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
13832 Defaults to @samp{#f}.
13836 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
13839 Defaults to @samp{#f}.
13846 @c %end of automatic openvpn-server documentation
13849 @deftp {Data Type} nginx-upstream-configuration
13850 Data type representing the configuration of an nginx @code{upstream}
13851 block. This type has the following parameters:
13855 Name for this group of servers.
13857 @item @code{servers}
13858 Specify the addresses of the servers in the group. The address can be
13859 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13860 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13861 prefix @samp{unix:}. For addresses using an IP address or domain name,
13862 the default port is 80, and a different port can be specified
13868 @deftp {Data Type} nginx-location-configuration
13869 Data type representing the configuration of an nginx @code{location}
13870 block. This type has the following parameters:
13874 URI which this location block matches.
13876 @anchor{nginx-location-configuration body}
13878 Body of the location block, specified as a string. This can contain many
13879 configuration directives. For example, to pass requests to a upstream
13880 server group defined using an @code{nginx-upstream-configuration} block,
13881 the following directive would be specified in the body @samp{proxy_pass
13882 http://upstream-name;}.
13887 @deftp {Data Type} nginx-named-location-configuration
13888 Data type representing the configuration of an nginx named location
13889 block. Named location blocks are used for request redirection, and not
13890 used for regular request processing. This type has the following
13895 Name to identify this location block.
13898 @xref{nginx-location-configuration body}, as the body for named location
13899 blocks can be used in a similar way to the
13900 @code{nginx-location-configuration body}. One restriction is that the
13901 body of a named location block cannot contain location blocks.
13906 @node Network File System
13907 @subsubsection Network File System
13910 The @code{(gnu services nfs)} module provides the following services,
13911 which are most commonly used in relation to mounting or exporting
13912 directory trees as @dfn{network file systems} (NFS).
13914 @subsubheading RPC Bind Service
13917 The RPC Bind service provides a facility to map program numbers into
13918 universal addresses.
13919 Many NFS related services use this facility. Hence it is automatically
13920 started when a dependent service starts.
13922 @defvr {Scheme Variable} rpcbind-service-type
13923 A service type for the RPC portmapper daemon.
13927 @deftp {Data Type} rpcbind-configuration
13928 Data type representing the configuration of the RPC Bind Service.
13929 This type has the following parameters:
13931 @item @code{rpcbind} (default: @code{rpcbind})
13932 The rpcbind package to use.
13934 @item @code{warm-start?} (default: @code{#t})
13935 If this parameter is @code{#t}, then the daemon will read a
13936 state file on startup thus reloading state information saved by a previous
13942 @subsubheading Pipefs Pseudo File System
13946 The pipefs file system is used to transfer NFS related data
13947 between the kernel and user space programs.
13949 @defvr {Scheme Variable} pipefs-service-type
13950 A service type for the pipefs pseudo file system.
13953 @deftp {Data Type} pipefs-configuration
13954 Data type representing the configuration of the pipefs pseudo file system service.
13955 This type has the following parameters:
13957 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13958 The directory to which the file system is to be attached.
13963 @subsubheading GSS Daemon Service
13966 @cindex global security system
13968 The @dfn{global security system} (GSS) daemon provides strong security for RPC
13970 Before exchanging RPC requests an RPC client must establish a security
13971 context. Typically this is done using the Kerberos command @command{kinit}
13972 or automatically at login time using PAM services (@pxref{Kerberos Services}).
13974 @defvr {Scheme Variable} gss-service-type
13975 A service type for the Global Security System (GSS) daemon.
13978 @deftp {Data Type} gss-configuration
13979 Data type representing the configuration of the GSS daemon service.
13980 This type has the following parameters:
13982 @item @code{nfs-utils} (default: @code{nfs-utils})
13983 The package in which the @command{rpc.gssd} command is to be found.
13985 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13986 The directory where the pipefs file system is mounted.
13992 @subsubheading IDMAP Daemon Service
13994 @cindex name mapper
13996 The idmap daemon service provides mapping between user IDs and user names.
13997 Typically it is required in order to access file systems mounted via NFSv4.
13999 @defvr {Scheme Variable} idmap-service-type
14000 A service type for the Identity Mapper (IDMAP) daemon.
14003 @deftp {Data Type} idmap-configuration
14004 Data type representing the configuration of the IDMAP daemon service.
14005 This type has the following parameters:
14007 @item @code{nfs-utils} (default: @code{nfs-utils})
14008 The package in which the @command{rpc.idmapd} command is to be found.
14010 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14011 The directory where the pipefs file system is mounted.
14013 @item @code{domain} (default: @code{#f})
14014 The local NFSv4 domain name.
14015 This must be a string or @code{#f}.
14016 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14021 @node Continuous Integration
14022 @subsubsection Continuous Integration
14024 @cindex continuous integration
14025 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14026 integration tool for Guix. It can be used both for development and for
14027 providing substitutes to others (@pxref{Substitutes}).
14029 The @code{(gnu services cuirass)} module provides the following service.
14031 @defvr {Scheme Procedure} cuirass-service-type
14032 The type of the Cuirass service. Its value must be a
14033 @code{cuirass-configuration} object, as described below.
14036 To add build jobs, you have to set the @code{specifications} field of
14037 the configuration. Here is an example of a service defining a build job
14038 based on a specification that can be found in Cuirass source tree. This
14039 service polls the Guix repository and builds a subset of the Guix
14040 packages, as prescribed in the @file{gnu-system.scm} example spec:
14043 (let ((spec #~((#:name . "guix")
14044 (#:url . "git://git.savannah.gnu.org/guix.git")
14045 (#:load-path . ".")
14047 ;; Here we must provide an absolute file name.
14048 ;; We take jobs from one of the examples provided
14050 (#:file . #$(file-append
14052 "/tests/gnu-system.scm"))
14054 (#:proc . hydra-jobs)
14055 (#:arguments (subset . "hello"))
14056 (#:branch . "master"))))
14057 (service cuirass-service-type
14058 (cuirass-configuration
14059 (specifications #~(list #$spec)))))
14062 While information related to build jobs is located directly in the
14063 specifications, global settings for the @command{cuirass} process are
14064 accessible in other @code{cuirass-configuration} fields.
14066 @deftp {Data Type} cuirass-configuration
14067 Data type representing the configuration of Cuirass.
14070 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14071 Location of the log file.
14073 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14074 Location of the repository cache.
14076 @item @code{user} (default: @code{"cuirass"})
14077 Owner of the @code{cuirass} process.
14079 @item @code{group} (default: @code{"cuirass"})
14080 Owner's group of the @code{cuirass} process.
14082 @item @code{interval} (default: @code{60})
14083 Number of seconds between the poll of the repositories followed by the
14086 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14087 Location of sqlite database which contains the build results and previously
14088 added specifications.
14090 @item @code{port} (default: @code{8080})
14091 Port number used by the HTTP server.
14093 @item @code{specifications} (default: @code{#~'()})
14094 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14095 where a specification is an association list
14096 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14097 keys are keywords (@code{#:keyword-example}) as shown in the example
14100 @item @code{use-substitutes?} (default: @code{#f})
14101 This allows using substitutes to avoid building every dependencies of a job
14104 @item @code{one-shot?} (default: @code{#f})
14105 Only evaluate specifications and build derivations once.
14107 @item @code{load-path} (default: @code{'()})
14108 This allows users to define their own packages and make them visible to
14109 cuirass as in @command{guix build} command.
14111 @item @code{cuirass} (default: @code{cuirass})
14112 The Cuirass package to use.
14116 @node Power management Services
14117 @subsubsection Power management Services
14119 @cindex power management with TLP
14120 The @code{(gnu services pm)} module provides a Guix service definition
14121 for the Linux power management tool TLP.
14123 TLP enables various powersaving modes in userspace and kernel.
14124 Contrary to @code{upower-service}, it is not a passive,
14125 monitoring tool, as it will apply custom settings each time a new power
14126 source is detected. More information can be found at
14127 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14129 @deffn {Scheme Variable} tlp-service-type
14130 The service type for the TLP tool. Its value should be a valid
14131 TLP configuration (see below). To use the default settings, simply
14134 (service tlp-service-type)
14138 By default TLP does not need much configuration but most TLP parameters
14139 can be tweaked using @code{tlp-configuration}.
14141 Each parameter definition is preceded by its type; for example,
14142 @samp{boolean foo} indicates that the @code{foo} parameter
14143 should be specified as a boolean. Types starting with
14144 @code{maybe-} denote parameters that won't show up in TLP config file
14145 when their value is @code{'disabled}.
14147 @c The following documentation was initially generated by
14148 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14149 @c documentation is better, so we shouldn't hesitate to edit below as
14150 @c needed. However if the change you want to make to this documentation
14151 @c can be done in an automated way, it's probably easier to change
14152 @c (generate-documentation) than to make it below and have to deal with
14153 @c the churn as TLP updates.
14155 Available @code{tlp-configuration} fields are:
14157 @deftypevr {@code{tlp-configuration} parameter} package tlp
14162 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14163 Set to true if you wish to enable TLP.
14165 Defaults to @samp{#t}.
14169 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14170 Default mode when no power supply can be detected. Alternatives are AC
14173 Defaults to @samp{"AC"}.
14177 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14178 Number of seconds Linux kernel has to wait after the disk goes idle,
14179 before syncing on AC.
14181 Defaults to @samp{0}.
14185 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14186 Same as @code{disk-idle-ac} but on BAT mode.
14188 Defaults to @samp{2}.
14192 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14193 Dirty pages flushing periodicity, expressed in seconds.
14195 Defaults to @samp{15}.
14199 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14200 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14202 Defaults to @samp{60}.
14206 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14207 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14208 alternatives are powersave and performance. With acpi-cpufreq driver,
14209 alternatives are ondemand, powersave, performance and conservative.
14211 Defaults to @samp{disabled}.
14215 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14216 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14218 Defaults to @samp{disabled}.
14222 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14223 Set the min available frequency for the scaling governor on AC.
14225 Defaults to @samp{disabled}.
14229 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14230 Set the max available frequency for the scaling governor on AC.
14232 Defaults to @samp{disabled}.
14236 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14237 Set the min available frequency for the scaling governor on BAT.
14239 Defaults to @samp{disabled}.
14243 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14244 Set the max available frequency for the scaling governor on BAT.
14246 Defaults to @samp{disabled}.
14250 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14251 Limit the min P-state to control the power dissipation of the CPU, in AC
14252 mode. Values are stated as a percentage of the available performance.
14254 Defaults to @samp{disabled}.
14258 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14259 Limit the max P-state to control the power dissipation of the CPU, in AC
14260 mode. Values are stated as a percentage of the available performance.
14262 Defaults to @samp{disabled}.
14266 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14267 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14269 Defaults to @samp{disabled}.
14273 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14274 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14276 Defaults to @samp{disabled}.
14280 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14281 Enable CPU turbo boost feature on AC mode.
14283 Defaults to @samp{disabled}.
14287 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14288 Same as @code{cpu-boost-on-ac?} on BAT mode.
14290 Defaults to @samp{disabled}.
14294 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14295 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14296 used under light load conditions.
14298 Defaults to @samp{#f}.
14302 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14303 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14305 Defaults to @samp{#t}.
14309 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14310 Enable Linux kernel NMI watchdog.
14312 Defaults to @samp{#f}.
14316 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14317 For Linux kernels with PHC patch applied, change CPU voltages. An
14318 example value would be @samp{"F:V F:V F:V F:V"}.
14320 Defaults to @samp{disabled}.
14324 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14325 Set CPU performance versus energy saving policy on AC. Alternatives are
14326 performance, normal, powersave.
14328 Defaults to @samp{"performance"}.
14332 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14333 Same as @code{energy-perf-policy-ac} but on BAT mode.
14335 Defaults to @samp{"powersave"}.
14339 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14344 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14345 Hard disk advanced power management level.
14349 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14350 Same as @code{disk-apm-bat} but on BAT mode.
14354 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14355 Hard disk spin down timeout. One value has to be specified for each
14356 declared hard disk.
14358 Defaults to @samp{disabled}.
14362 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14363 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14365 Defaults to @samp{disabled}.
14369 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14370 Select IO scheduler for disk devices. One value has to be specified for
14371 each declared hard disk. Example alternatives are cfq, deadline and
14374 Defaults to @samp{disabled}.
14378 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14379 SATA aggressive link power management (ALPM) level. Alternatives are
14380 min_power, medium_power, max_performance.
14382 Defaults to @samp{"max_performance"}.
14386 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14387 Same as @code{sata-linkpwr-ac} but on BAT mode.
14389 Defaults to @samp{"min_power"}.
14393 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14394 Exclude specified SATA host devices for link power management.
14396 Defaults to @samp{disabled}.
14400 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14401 Enable Runtime Power Management for AHCI controller and disks on AC
14404 Defaults to @samp{disabled}.
14408 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14409 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14411 Defaults to @samp{disabled}.
14415 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14416 Seconds of inactivity before disk is suspended.
14418 Defaults to @samp{15}.
14422 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14423 PCI Express Active State Power Management level. Alternatives are
14424 default, performance, powersave.
14426 Defaults to @samp{"performance"}.
14430 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14431 Same as @code{pcie-aspm-ac} but on BAT mode.
14433 Defaults to @samp{"powersave"}.
14437 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14438 Radeon graphics clock speed level. Alternatives are low, mid, high,
14441 Defaults to @samp{"high"}.
14445 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14446 Same as @code{radeon-power-ac} but on BAT mode.
14448 Defaults to @samp{"low"}.
14452 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14453 Radeon dynamic power management method (DPM). Alternatives are battery,
14456 Defaults to @samp{"performance"}.
14460 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14461 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14463 Defaults to @samp{"battery"}.
14467 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14468 Radeon DPM performance level. Alternatives are auto, low, high.
14470 Defaults to @samp{"auto"}.
14474 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14475 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14477 Defaults to @samp{"auto"}.
14481 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14482 Wifi power saving mode.
14484 Defaults to @samp{#f}.
14488 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14489 Same as @code{wifi-power-ac?} but on BAT mode.
14491 Defaults to @samp{#t}.
14495 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14496 Disable wake on LAN.
14498 Defaults to @samp{#t}.
14502 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14503 Timeout duration in seconds before activating audio power saving on
14504 Intel HDA and AC97 devices. A value of 0 disables power saving.
14506 Defaults to @samp{0}.
14510 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14511 Same as @code{sound-powersave-ac} but on BAT mode.
14513 Defaults to @samp{1}.
14517 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
14518 Disable controller in powersaving mode on Intel HDA devices.
14520 Defaults to @samp{#t}.
14524 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
14525 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
14526 powered on again by releasing (and reinserting) the eject lever or by
14527 pressing the disc eject button on newer models.
14529 Defaults to @samp{#f}.
14533 @deftypevr {@code{tlp-configuration} parameter} string bay-device
14534 Name of the optical drive device to power off.
14536 Defaults to @samp{"sr0"}.
14540 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
14541 Runtime Power Management for PCI(e) bus devices. Alternatives are on
14544 Defaults to @samp{"on"}.
14548 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
14549 Same as @code{runtime-pm-ac} but on BAT mode.
14551 Defaults to @samp{"auto"}.
14555 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
14556 Runtime Power Management for all PCI(e) bus devices, except blacklisted
14559 Defaults to @samp{#t}.
14563 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
14564 Exclude specified PCI(e) device addresses from Runtime Power Management.
14566 Defaults to @samp{disabled}.
14570 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
14571 Exclude PCI(e) devices assigned to the specified drivers from Runtime
14576 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
14577 Enable USB autosuspend feature.
14579 Defaults to @samp{#t}.
14583 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
14584 Exclude specified devices from USB autosuspend.
14586 Defaults to @samp{disabled}.
14590 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
14591 Exclude WWAN devices from USB autosuspend.
14593 Defaults to @samp{#t}.
14597 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
14598 Include specified devices into USB autosuspend, even if they are already
14599 excluded by the driver or via @code{usb-blacklist-wwan?}.
14601 Defaults to @samp{disabled}.
14605 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
14606 Enable USB autosuspend before shutdown.
14608 Defaults to @samp{disabled}.
14612 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
14613 Restore radio device state (bluetooth, wifi, wwan) from previous
14614 shutdown on system startup.
14616 Defaults to @samp{#f}.
14621 The @code{(gnu services pm)} module provides an interface to
14622 thermald, a CPU frequency scaling service which helps prevent overheating.
14624 @defvr {Scheme Variable} thermald-service-type
14625 This is the service type for
14626 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
14627 Thermal Daemon, which is responsible for controlling the thermal state
14628 of processors and preventing overheating.
14631 @deftp {Data Type} thermald-configuration
14632 Data type representing the configuration of @code{thermald-service-type}.
14635 @item @code{ignore-cpuid-check?} (default: @code{#f})
14636 Ignore cpuid check for supported CPU models.
14638 @item @code{thermald} (default: @var{thermald})
14639 Package object of thermald.
14645 @node Miscellaneous Services
14646 @subsubsection Miscellaneous Services
14650 @subsubheading Lirc Service
14652 The @code{(gnu services lirc)} module provides the following service.
14654 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
14655 [#:device #f] [#:driver #f] [#:config-file #f] @
14656 [#:extra-options '()]
14657 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
14658 decodes infrared signals from remote controls.
14660 Optionally, @var{device}, @var{driver} and @var{config-file}
14661 (configuration file name) may be specified. See @command{lircd} manual
14664 Finally, @var{extra-options} is a list of additional command-line options
14665 passed to @command{lircd}.
14669 @subsubheading Spice Service
14671 The @code{(gnu services spice)} module provides the following service.
14673 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
14674 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
14675 that enables sharing the clipboard with a vm and setting the guest display
14676 resolution when the graphical console window resizes.
14679 @subsubsection Dictionary Services
14681 The @code{(gnu services dict)} module provides the following service:
14683 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
14684 Return a service that runs the @command{dicod} daemon, an implementation
14685 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
14687 The optional @var{config} argument specifies the configuration for
14688 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
14689 default it serves the GNU Collaborative International Dictonary of English.
14691 You can add @command{open localhost} to your @file{~/.dico} file to make
14692 @code{localhost} the default server for @command{dico} client
14693 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
14696 @deftp {Data Type} dicod-configuration
14697 Data type representing the configuration of dicod.
14700 @item @code{dico} (default: @var{dico})
14701 Package object of the GNU Dico dictionary server.
14703 @item @code{interfaces} (default: @var{'("localhost")})
14704 This is the list of IP addresses and ports and possibly socket file
14705 names to listen to (@pxref{Server Settings, @code{listen} directive,,
14706 dico, GNU Dico Manual}).
14708 @item @code{handlers} (default: @var{'()})
14709 List of @code{<dicod-handler>} objects denoting handlers (module instances).
14711 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
14712 List of @code{<dicod-database>} objects denoting dictionaries to be served.
14716 @deftp {Data Type} dicod-handler
14717 Data type representing a dictionary handler (module instance).
14721 Name of the handler (module instance).
14723 @item @code{module} (default: @var{#f})
14724 Name of the dicod module of the handler (instance). If it is @code{#f},
14725 the module has the same name as the handler.
14726 (@pxref{Modules,,, dico, GNU Dico Manual}).
14728 @item @code{options}
14729 List of strings or gexps representing the arguments for the module handler
14733 @deftp {Data Type} dicod-database
14734 Data type representing a dictionary database.
14738 Name of the database, will be used in DICT commands.
14740 @item @code{handler}
14741 Name of the dicod handler (module instance) used by this database
14742 (@pxref{Handlers,,, dico, GNU Dico Manual}).
14744 @item @code{complex?} (default: @var{#f})
14745 Whether the database configuration complex. The complex configuration
14746 will need a corresponding @code{<dicod-handler>} object, otherwise not.
14748 @item @code{options}
14749 List of strings or gexps representing the arguments for the database
14750 (@pxref{Databases,,, dico, GNU Dico Manual}).
14754 @defvr {Scheme Variable} %dicod-database:gcide
14755 A @code{<dicod-database>} object serving the GNU Collaborative International
14756 Dictionary of English using the @code{gcide} package.
14759 The following is an example @code{dicod-service} configuration.
14762 (dicod-service #:config
14763 (dicod-configuration
14764 (handlers (list (dicod-handler
14768 (list #~(string-append "dbdir=" #$wordnet))))))
14769 (databases (list (dicod-database
14772 (handler "wordnet")
14773 (options '("database=wn")))
14774 %dicod-database:gcide))))
14777 @subsubsection Version Control
14779 The @code{(gnu services version-control)} module provides the following services:
14781 @subsubheading Git daemon service
14783 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
14785 Return a service that runs @command{git daemon}, a simple TCP server to
14786 expose repositories over the Git protocol for anonymous access.
14788 The optional @var{config} argument should be a
14789 @code{<git-daemon-configuration>} object, by default it allows read-only
14790 access to exported@footnote{By creating the magic file
14791 "git-daemon-export-ok" in the repository directory.} repositories under
14796 @deftp {Data Type} git-daemon-configuration
14797 Data type representing the configuration for @code{git-daemon-service}.
14800 @item @code{package} (default: @var{git})
14801 Package object of the Git distributed version control system.
14803 @item @code{export-all?} (default: @var{#f})
14804 Whether to allow access for all Git repositories, even if they do not
14805 have the @file{git-daemon-export-ok} file.
14807 @item @code{base-path} (default: @file{/srv/git})
14808 Whether to remap all the path requests as relative to the given path.
14809 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
14810 then if you later try to pull @code{git://example.com/hello.git}, git
14811 daemon will interpret the path as @code{/srv/git/hello.git}.
14813 @item @code{user-path} (default: @var{#f})
14814 Whether to allow @code{~user} notation to be used in requests. When
14815 specified with empty string, requests to @code{git://host/~alice/foo} is
14816 taken as a request to access @code{foo} repository in the home directory
14817 of user @code{alice}. If @var{(user-path "path")} is specified, the
14818 same request is taken as a request to access @code{path/foo} repository
14819 in the home directory of user @code{alice}.
14821 @item @code{listen} (default: @var{'()})
14822 Whether to listen on specific IP addresses or hostnames, defaults to
14825 @item @code{port} (default: @var{#f})
14826 Whether to listen on an alternative port, which defaults to 9418.
14828 @item @code{whitelist} (default: @var{'()})
14829 If not empty, only allow access to this list of directories.
14831 @item @code{extra-options} (default: @var{'()})
14832 Extra options will be passed to @code{git daemon}, please run
14833 @command{man git-daemon} for more information.
14838 @node Setuid Programs
14839 @subsection Setuid Programs
14841 @cindex setuid programs
14842 Some programs need to run with ``root'' privileges, even when they are
14843 launched by unprivileged users. A notorious example is the
14844 @command{passwd} program, which users can run to change their
14845 password, and which needs to access the @file{/etc/passwd} and
14846 @file{/etc/shadow} files---something normally restricted to root, for
14847 obvious security reasons. To address that, these executables are
14848 @dfn{setuid-root}, meaning that they always run with root privileges
14849 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
14850 for more info about the setuid mechanism.)
14852 The store itself @emph{cannot} contain setuid programs: that would be a
14853 security issue since any user on the system can write derivations that
14854 populate the store (@pxref{The Store}). Thus, a different mechanism is
14855 used: instead of changing the setuid bit directly on files that are in
14856 the store, we let the system administrator @emph{declare} which programs
14857 should be setuid root.
14859 The @code{setuid-programs} field of an @code{operating-system}
14860 declaration contains a list of G-expressions denoting the names of
14861 programs to be setuid-root (@pxref{Using the Configuration System}).
14862 For instance, the @command{passwd} program, which is part of the Shadow
14863 package, can be designated by this G-expression (@pxref{G-Expressions}):
14866 #~(string-append #$shadow "/bin/passwd")
14869 A default set of setuid programs is defined by the
14870 @code{%setuid-programs} variable of the @code{(gnu system)} module.
14872 @defvr {Scheme Variable} %setuid-programs
14873 A list of G-expressions denoting common programs that are setuid-root.
14875 The list includes commands such as @command{passwd}, @command{ping},
14876 @command{su}, and @command{sudo}.
14879 Under the hood, the actual setuid programs are created in the
14880 @file{/run/setuid-programs} directory at system activation time. The
14881 files in this directory refer to the ``real'' binaries, which are in the
14884 @node X.509 Certificates
14885 @subsection X.509 Certificates
14887 @cindex HTTPS, certificates
14888 @cindex X.509 certificates
14890 Web servers available over HTTPS (that is, HTTP over the transport-layer
14891 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
14892 that the client can then use to @emph{authenticate} the server. To do
14893 that, clients verify that the server's certificate is signed by a
14894 so-called @dfn{certificate authority} (CA). But to verify the CA's
14895 signature, clients must have first acquired the CA's certificate.
14897 Web browsers such as GNU@tie{}IceCat include their own set of CA
14898 certificates, such that they are able to verify CA signatures
14901 However, most other programs that can talk HTTPS---@command{wget},
14902 @command{git}, @command{w3m}, etc.---need to be told where CA
14903 certificates can be found.
14905 @cindex @code{nss-certs}
14906 In GuixSD, this is done by adding a package that provides certificates
14907 to the @code{packages} field of the @code{operating-system} declaration
14908 (@pxref{operating-system Reference}). GuixSD includes one such package,
14909 @code{nss-certs}, which is a set of CA certificates provided as part of
14910 Mozilla's Network Security Services.
14912 Note that it is @emph{not} part of @var{%base-packages}, so you need to
14913 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
14914 most applications and libraries look for certificates by default, points
14915 to the certificates installed globally.
14917 Unprivileged users, including users of Guix on a foreign distro,
14918 can also install their own certificate package in
14919 their profile. A number of environment variables need to be defined so
14920 that applications and libraries know where to find them. Namely, the
14921 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
14922 variables. Some applications add their own environment variables; for
14923 instance, the Git version control system honors the certificate bundle
14924 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
14925 would typically run something like:
14928 $ guix package -i nss-certs
14929 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
14930 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14931 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
14934 As another example, R requires the @code{CURL_CA_BUNDLE} environment
14935 variable to point to a certificate bundle, so you would have to run
14936 something like this:
14939 $ guix package -i nss-certs
14940 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14943 For other applications you may want to look up the required environment
14944 variable in the relevant documentation.
14947 @node Name Service Switch
14948 @subsection Name Service Switch
14950 @cindex name service switch
14952 The @code{(gnu system nss)} module provides bindings to the
14953 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
14954 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
14955 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
14956 extended with new ``name'' lookup methods for system databases, which
14957 includes host names, service names, user accounts, and more (@pxref{Name
14958 Service Switch, System Databases and Name Service Switch,, libc, The GNU
14959 C Library Reference Manual}).
14961 The NSS configuration specifies, for each system database, which lookup
14962 method is to be used, and how the various methods are chained
14963 together---for instance, under which circumstances NSS should try the
14964 next method in the list. The NSS configuration is given in the
14965 @code{name-service-switch} field of @code{operating-system} declarations
14966 (@pxref{operating-system Reference, @code{name-service-switch}}).
14969 @cindex .local, host name lookup
14970 As an example, the declaration below configures the NSS to use the
14971 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
14972 back-end}, which supports host name lookups over multicast DNS (mDNS)
14973 for host names ending in @code{.local}:
14976 (name-service-switch
14977 (hosts (list %files ;first, check /etc/hosts
14979 ;; If the above did not succeed, try
14980 ;; with 'mdns_minimal'.
14982 (name "mdns_minimal")
14984 ;; 'mdns_minimal' is authoritative for
14985 ;; '.local'. When it returns "not found",
14986 ;; no need to try the next methods.
14987 (reaction (lookup-specification
14988 (not-found => return))))
14990 ;; Then fall back to DNS.
14994 ;; Finally, try with the "full" 'mdns'.
14999 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15000 contains this configuration, so you will not have to type it if all you
15001 want is to have @code{.local} host lookup working.
15003 Note that, in this case, in addition to setting the
15004 @code{name-service-switch} of the @code{operating-system} declaration,
15005 you also need to use @code{avahi-service} (@pxref{Networking Services,
15006 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15007 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15008 to the name service cache daemon (@pxref{Base Services,
15009 @code{nscd-service}}).
15011 For convenience, the following variables provide typical NSS
15014 @defvr {Scheme Variable} %default-nss
15015 This is the default name service switch configuration, a
15016 @code{name-service-switch} object.
15019 @defvr {Scheme Variable} %mdns-host-lookup-nss
15020 This is the name service switch configuration with support for host name
15021 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
15024 The reference for name service switch configuration is given below. It
15025 is a direct mapping of the configuration file format of the C library , so
15026 please refer to the C library manual for more information (@pxref{NSS
15027 Configuration File,,, libc, The GNU C Library Reference Manual}).
15028 Compared to the configuration file format of libc NSS, it has the advantage
15029 not only of adding this warm parenthetic feel that we like, but also
15030 static checks: you will know about syntax errors and typos as soon as you
15031 run @command{guix system}.
15033 @deftp {Data Type} name-service-switch
15035 This is the data type representation the configuration of libc's name
15036 service switch (NSS). Each field below represents one of the supported
15053 The system databases handled by the NSS. Each of these fields must be a
15054 list of @code{<name-service>} objects (see below).
15058 @deftp {Data Type} name-service
15060 This is the data type representing an actual name service and the
15061 associated lookup action.
15065 A string denoting the name service (@pxref{Services in the NSS
15066 configuration,,, libc, The GNU C Library Reference Manual}).
15068 Note that name services listed here must be visible to nscd. This is
15069 achieved by passing the @code{#:name-services} argument to
15070 @code{nscd-service} the list of packages providing the needed name
15071 services (@pxref{Base Services, @code{nscd-service}}).
15074 An action specified using the @code{lookup-specification} macro
15075 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15076 Reference Manual}). For example:
15079 (lookup-specification (unavailable => continue)
15080 (success => return))
15085 @node Initial RAM Disk
15086 @subsection Initial RAM Disk
15089 @cindex initial RAM disk
15090 For bootstrapping purposes, the Linux-Libre kernel is passed an
15091 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15092 root file system as well as an initialization script. The latter is
15093 responsible for mounting the real root file system, and for loading any
15094 kernel modules that may be needed to achieve that.
15096 The @code{initrd} field of an @code{operating-system} declaration allows
15097 you to specify which initrd you would like to use. The @code{(gnu
15098 system linux-initrd)} module provides three ways to build an initrd: the
15099 high-level @code{base-initrd} procedure and the low-level
15100 @code{raw-initrd} and @code{expression->initrd} procedures.
15102 The @code{base-initrd} procedure is intended to cover most common uses.
15103 For example, if you want to add a bunch of kernel modules to be loaded
15104 at boot time, you can define the @code{initrd} field of the operating
15105 system declaration like this:
15108 (initrd (lambda (file-systems . rest)
15109 ;; Create a standard initrd that has modules "foo.ko"
15110 ;; and "bar.ko", as well as their dependencies, in
15111 ;; addition to the modules available by default.
15112 (apply base-initrd file-systems
15113 #:extra-modules '("foo" "bar")
15117 The @code{base-initrd} procedure also handles common use cases that
15118 involves using the system as a QEMU guest, or as a ``live'' system with
15119 volatile root file system.
15121 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15122 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15123 such as trying to guess which kernel modules and packages should be included
15124 to the initrd. An example use of @code{raw-initrd} is when a user has
15125 a custom Linux kernel configuration and default kernel modules included by
15126 @code{base-initrd} are not available.
15128 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15129 honors several options passed on the Linux kernel command line
15130 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15131 @code{-append} option of QEMU), notably:
15134 @item --load=@var{boot}
15135 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15136 program, once it has mounted the root file system.
15138 GuixSD uses this option to yield control to a boot program that runs the
15139 service activation programs and then spawns the GNU@tie{}Shepherd, the
15140 initialization system.
15142 @item --root=@var{root}
15143 Mount @var{root} as the root file system. @var{root} can be a
15144 device name like @code{/dev/sda1}, a partition label, or a partition
15147 @item --system=@var{system}
15148 Have @file{/run/booted-system} and @file{/run/current-system} point to
15151 @item modprobe.blacklist=@var{modules}@dots{}
15152 @cindex module, black-listing
15153 @cindex black list, of kernel modules
15154 Instruct the initial RAM disk as well as the @command{modprobe} command
15155 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15156 must be a comma-separated list of module names---e.g.,
15157 @code{usbkbd,9pnet}.
15160 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15161 tries to load kernel modules and to mount the root file system. Our
15162 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15163 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15164 Manual}, for more information on Guile's REPL.
15168 Now that you know all the features that initial RAM disks produced by
15169 @code{base-initrd} and @code{raw-initrd} provide,
15170 here is how to use it and customize it further.
15173 @cindex initial RAM disk
15174 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15175 [#:linux-modules '()] [#:mapped-devices '()] @
15176 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15177 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15178 a list of file systems to be mounted by the initrd, possibly in addition to
15179 the root file system specified on the kernel command line via @code{--root}.
15180 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15181 @var{mapped-devices} is a list of device mappings to realize before
15182 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15183 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15184 include @code{e2fsck/static} or other packages needed by the initrd to check
15187 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15188 parameters. When @var{virtio?} is true, load additional modules so that the
15189 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15191 When @var{volatile-root?} is true, the root file system is writable but any changes
15195 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15196 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15197 [#:virtio? #t] [#:extra-modules '()]
15198 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15199 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15200 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15201 also behaves as in @code{raw-initrd}.
15203 When @var{virtio?} is true, load additional modules so that the
15204 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15206 The initrd is automatically populated with all the kernel modules necessary
15207 for @var{file-systems} and for the given options. However, additional kernel
15208 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15209 loaded at boot time in the order in which they appear.
15212 Needless to say, the initrds we produce and use embed a
15213 statically-linked Guile, and the initialization program is a Guile
15214 program. That gives a lot of flexibility. The
15215 @code{expression->initrd} procedure builds such an initrd, given the
15216 program to run in that initrd.
15218 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15219 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15220 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15221 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15222 upon booting. All the derivations referenced by @var{exp} are
15223 automatically copied to the initrd.
15226 @node GRUB Configuration
15227 @subsection GRUB Configuration
15230 @cindex boot loader
15232 The operating system uses GNU@tie{}GRUB as its boot loader
15233 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
15234 configured using a @code{grub-configuration} declaration. This data type
15235 is exported by the @code{(gnu system grub)} module and described below.
15237 @deftp {Data Type} grub-configuration
15238 The type of a GRUB configuration declaration.
15242 @item @code{device}
15243 This is a string denoting the boot device. It must be a device name
15244 understood by the @command{grub-install} command, such as
15245 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
15248 @item @code{menu-entries} (default: @code{()})
15249 A possibly empty list of @code{menu-entry} objects (see below), denoting
15250 entries to appear in the GRUB boot menu, in addition to the current
15251 system entry and the entry pointing to previous system generations.
15253 @item @code{default-entry} (default: @code{0})
15254 The index of the default boot menu entry. Index 0 is for the entry of the
15257 @item @code{timeout} (default: @code{5})
15258 The number of seconds to wait for keyboard input before booting. Set to
15259 0 to boot immediately, and to -1 to wait indefinitely.
15261 @item @code{theme} (default: @var{%default-theme})
15262 The @code{grub-theme} object describing the theme to use.
15264 @item @code{grub} (default: @code{grub})
15265 The GRUB package to use.
15267 @item @code{terminal-outputs} (default: @code{'gfxterm})
15268 The output terminals used for the GRUB boot menu, as a list of symbols.
15269 These values are accepted: @code{console}, @code{serial},
15270 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text}, @code{mda_text},
15271 @code{morse}, and @code{pkmodem}. This field corresponds to the GRUB
15272 variable GRUB_TERMINAL_OUTPUT (@pxref{Simple configuration,,, grub,GNU
15275 @item @code{terminal-inputs} (default: @code{'()})
15276 The input terminals used for the GRUB boot menu, as a list of symbols.
15277 The default is the native platform terminal as determined by GRUB at
15278 run-time. These values are accepted: @code{console}, @code{serial},
15279 @code{serial_@{0-3@}}, @code{at_keyboard}, and @code{usb_keyboard}.
15280 This field corresponds to the GRUB variable GRUB_TERMINAL_INPUT
15281 (@pxref{Simple configuration,,, grub,GNU GRUB manual}).
15283 @item @code{serial-unit} (default: @code{#f})
15284 The serial unit used by GRUB, as an integer from 0 to 3. The default
15285 value is chosen by GRUB at run-time; currently GRUB chooses 0, which
15286 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15288 @item @code{serial-speed} (default: @code{#f})
15289 The speed of the serial interface, as an integer. The default value is
15290 chosen by GRUB at run-time; currently GRUB chooses 9600@tie{}bps
15291 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15298 Should you want to list additional boot menu entries @i{via} the
15299 @code{menu-entries} field above, you will need to create them with the
15300 @code{menu-entry} form. For example, imagine you want to be able to
15301 boot another distro (hard to imagine!), you can define a menu entry
15306 (label "The Other Distro")
15307 (linux "/boot/old/vmlinux-2.6.32")
15308 (linux-arguments '("root=/dev/sda2"))
15309 (initrd "/boot/old/initrd"))
15314 @deftp {Data Type} menu-entry
15315 The type of an entry in the GRUB boot menu.
15320 The label to show in the menu---e.g., @code{"GNU"}.
15323 The Linux kernel image to boot, for example:
15326 (file-append linux-libre "/bzImage")
15329 It is also possible to specify a device explicitly in the file path
15330 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
15331 GNU GRUB manual}), for example:
15334 "(hd0,msdos1)/boot/vmlinuz"
15337 If the device is specified explicitly as above, then the @code{device}
15338 field is ignored entirely.
15340 @item @code{linux-arguments} (default: @code{()})
15341 The list of extra Linux kernel command-line arguments---e.g.,
15342 @code{("console=ttyS0")}.
15344 @item @code{initrd}
15345 A G-Expression or string denoting the file name of the initial RAM disk
15346 to use (@pxref{G-Expressions}).
15348 @item @code{device} (default: @code{#f})
15349 The device where the kernel and initrd are to be found---i.e., the GRUB
15350 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15352 This may be a file system label (a string), a file system UUID (a
15353 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
15354 search the device containing the file specified by the @code{linux}
15355 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
15356 an OS device name such as @file{/dev/sda1}.
15358 @item @code{device-mount-point} (default: @code{"/"})
15359 The mount point of the above device on the system. You probably do not
15360 need to change the default value. GuixSD uses it to strip the prefix of
15361 store file names for systems where @file{/gnu} or @file{/gnu/store} is
15362 on a separate partition.
15367 @c FIXME: Write documentation once it's stable.
15368 Themes are created using the @code{grub-theme} form, which is not
15371 @defvr {Scheme Variable} %default-theme
15372 This is the default GRUB theme used by the operating system, with a
15373 fancy background image displaying the GNU and Guix logos.
15377 @node Invoking guix system
15378 @subsection Invoking @code{guix system}
15380 Once you have written an operating system declaration as seen in the
15381 previous section, it can be @dfn{instantiated} using the @command{guix
15382 system} command. The synopsis is:
15385 guix system @var{options}@dots{} @var{action} @var{file}
15388 @var{file} must be the name of a file containing an
15389 @code{operating-system} declaration. @var{action} specifies how the
15390 operating system is instantiated. Currently the following values are
15395 Build the operating system described in @var{file}, activate it, and
15396 switch to it@footnote{This action (and the related actions
15397 @code{switch-generation} and @code{roll-back}) are usable only on
15398 systems already running GuixSD.}.
15400 This effects all the configuration specified in @var{file}: user
15401 accounts, system services, global package list, setuid programs, etc.
15402 The command starts system services specified in @var{file} that are not
15403 currently running; if a service is currently running, it does not
15404 attempt to upgrade it since this would not be possible without stopping it
15407 This command creates a new generation whose number is one greater than
15408 the current generation (as reported by @command{guix system
15409 list-generations}). If that generation already exists, it will be
15410 overwritten. This behavior mirrors that of @command{guix package}
15411 (@pxref{Invoking guix package}).
15413 It also adds a GRUB menu entry for the new OS configuration, and moves
15414 entries for older configurations to a submenu---unless
15415 @option{--no-bootloader} is passed.
15418 @c The paragraph below refers to the problem discussed at
15419 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15420 It is highly recommended to run @command{guix pull} once before you run
15421 @command{guix system reconfigure} for the first time (@pxref{Invoking
15422 guix pull}). Failing to do that you would see an older version of Guix
15423 once @command{reconfigure} has completed.
15426 @item switch-generation
15427 @cindex generations
15428 Switch to an existing system generation. This action atomically
15429 switches the system profile to the specified system generation. It also
15430 rearranges the system's existing GRUB menu entries. It makes the menu
15431 entry for the specified system generation the default, and it moves the
15432 entries for the other generations to a submenu. The next time the
15433 system boots, it will use the specified system generation.
15435 The target generation can be specified explicitly by its generation
15436 number. For example, the following invocation would switch to system
15440 guix system switch-generation 7
15443 The target generation can also be specified relative to the current
15444 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15445 ``3 generations ahead of the current generation,'' and @code{-1} means
15446 ``1 generation prior to the current generation.'' When specifying a
15447 negative value such as @code{-1}, you must precede it with @code{--} to
15448 prevent it from being parsed as an option. For example:
15451 guix system switch-generation -- -1
15454 Currently, the effect of invoking this action is @emph{only} to switch
15455 the system profile to an existing generation and rearrange the GRUB menu
15456 entries. To actually start using the target system generation, you must
15457 reboot after running this action. In the future, it will be updated to
15458 do the same things as @command{reconfigure}, like activating and
15459 deactivating services.
15461 This action will fail if the specified generation does not exist.
15464 @cindex rolling back
15465 Switch to the preceding system generation. The next time the system
15466 boots, it will use the preceding system generation. This is the inverse
15467 of @command{reconfigure}, and it is exactly the same as invoking
15468 @command{switch-generation} with an argument of @code{-1}.
15470 Currently, as with @command{switch-generation}, you must reboot after
15471 running this action to actually start using the preceding system
15475 Build the derivation of the operating system, which includes all the
15476 configuration files and programs needed to boot and run the system.
15477 This action does not actually install anything.
15480 Populate the given directory with all the files necessary to run the
15481 operating system specified in @var{file}. This is useful for first-time
15482 installations of GuixSD. For instance:
15485 guix system init my-os-config.scm /mnt
15488 copies to @file{/mnt} all the store items required by the configuration
15489 specified in @file{my-os-config.scm}. This includes configuration
15490 files, packages, and so on. It also creates other essential files
15491 needed for the system to operate correctly---e.g., the @file{/etc},
15492 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
15494 This command also installs GRUB on the device specified in
15495 @file{my-os-config}, unless the @option{--no-bootloader} option was passed.
15498 @cindex virtual machine
15500 @anchor{guix system vm}
15501 Build a virtual machine that contains the operating system declared in
15502 @var{file}, and return a script to run that virtual machine (VM).
15503 Arguments given to the script are passed to QEMU.
15505 The VM shares its store with the host system.
15507 Additional file systems can be shared between the host and the VM using
15508 the @code{--share} and @code{--expose} command-line options: the former
15509 specifies a directory to be shared with write access, while the latter
15510 provides read-only access to the shared directory.
15512 The example below creates a VM in which the user's home directory is
15513 accessible read-only, and where the @file{/exchange} directory is a
15514 read-write mapping of @file{$HOME/tmp} on the host:
15517 guix system vm my-config.scm \
15518 --expose=$HOME --share=$HOME/tmp=/exchange
15521 On GNU/Linux, the default is to boot directly to the kernel; this has
15522 the advantage of requiring only a very tiny root disk image since the
15523 store of the host can then be mounted.
15525 The @code{--full-boot} option forces a complete boot sequence, starting
15526 with the bootloader. This requires more disk space since a root image
15527 containing at least the kernel, initrd, and bootloader data files must
15528 be created. The @code{--image-size} option can be used to specify the
15533 Return a virtual machine or disk image of the operating system declared
15534 in @var{file} that stands alone. Use the @option{--image-size} option
15535 to specify the size of the image.
15537 When using @code{vm-image}, the returned image is in qcow2 format, which
15538 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
15539 for more information on how to run the image in a virtual machine.
15541 When using @code{disk-image}, a raw disk image is produced; it can be
15542 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
15543 the device corresponding to a USB stick, one can copy the image to it
15544 using the following command:
15547 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
15551 Return a script to run the operating system declared in @var{file}
15552 within a container. Containers are a set of lightweight isolation
15553 mechanisms provided by the kernel Linux-libre. Containers are
15554 substantially less resource-demanding than full virtual machines since
15555 the kernel, shared objects, and other resources can be shared with the
15556 host system; this also means they provide thinner isolation.
15558 Currently, the script must be run as root in order to support more than
15559 a single user and group. The container shares its store with the host
15562 As with the @code{vm} action (@pxref{guix system vm}), additional file
15563 systems to be shared between the host and container can be specified
15564 using the @option{--share} and @option{--expose} options:
15567 guix system container my-config.scm \
15568 --expose=$HOME --share=$HOME/tmp=/exchange
15572 This option requires Linux-libre 3.19 or newer.
15577 @var{options} can contain any of the common build options (@pxref{Common
15578 Build Options}). In addition, @var{options} can contain one of the
15582 @item --system=@var{system}
15583 @itemx -s @var{system}
15584 Attempt to build for @var{system} instead of the host system type.
15585 This works as per @command{guix build} (@pxref{Invoking guix build}).
15589 Return the derivation file name of the given operating system without
15592 @item --image-size=@var{size}
15593 For the @code{vm-image} and @code{disk-image} actions, create an image
15594 of the given @var{size}. @var{size} may be a number of bytes, or it may
15595 include a unit as a suffix (@pxref{Block size, size specifications,,
15596 coreutils, GNU Coreutils}).
15598 @item --root=@var{file}
15599 @itemx -r @var{file}
15600 Make @var{file} a symlink to the result, and register it as a garbage
15603 @item --on-error=@var{strategy}
15604 Apply @var{strategy} when an error occurs when reading @var{file}.
15605 @var{strategy} may be one of the following:
15608 @item nothing-special
15609 Report the error concisely and exit. This is the default strategy.
15612 Likewise, but also display a backtrace.
15615 Report the error and enter Guile's debugger. From there, you can run
15616 commands such as @code{,bt} to get a backtrace, @code{,locals} to
15617 display local variable values, and more generally inspect the state of the
15618 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
15619 a list of available debugging commands.
15624 All the actions above, except @code{build} and @code{init},
15625 can use KVM support in the Linux-libre kernel. Specifically, if the
15626 machine has hardware virtualization support, the corresponding
15627 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
15628 must exist and be readable and writable by the user and by the
15629 build users of the daemon (@pxref{Build Environment Setup}).
15632 Once you have built, configured, re-configured, and re-re-configured
15633 your GuixSD installation, you may find it useful to list the operating
15634 system generations available on disk---and that you can choose from the
15639 @item list-generations
15640 List a summary of each generation of the operating system available on
15641 disk, in a human-readable way. This is similar to the
15642 @option{--list-generations} option of @command{guix package}
15643 (@pxref{Invoking guix package}).
15645 Optionally, one can specify a pattern, with the same syntax that is used
15646 in @command{guix package --list-generations}, to restrict the list of
15647 generations displayed. For instance, the following command displays
15648 generations that are up to 10 days old:
15651 $ guix system list-generations 10d
15656 The @command{guix system} command has even more to offer! The following
15657 sub-commands allow you to visualize how your system services relate to
15660 @anchor{system-extension-graph}
15663 @item extension-graph
15664 Emit in Dot/Graphviz format to standard output the @dfn{service
15665 extension graph} of the operating system defined in @var{file}
15666 (@pxref{Service Composition}, for more information on service
15672 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
15675 produces a PDF file showing the extension relations among services.
15677 @anchor{system-shepherd-graph}
15678 @item shepherd-graph
15679 Emit in Dot/Graphviz format to standard output the @dfn{dependency
15680 graph} of shepherd services of the operating system defined in
15681 @var{file}. @xref{Shepherd Services}, for more information and for an
15686 @node Running GuixSD in a VM
15687 @subsection Running GuixSD in a Virtual Machine
15689 @cindex virtual machine
15690 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
15691 virtual machine image using @command{guix system vm-image}
15692 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
15693 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
15696 To run the image in QEMU, copy it out of the store (@pxref{The Store})
15697 and give yourself permission to write to the copy. When invoking QEMU,
15698 you must choose a system emulator that is suitable for your hardware
15699 platform. Here is a minimal QEMU invocation that will boot the result
15700 of @command{guix system vm-image} on x86_64 hardware:
15703 $ qemu-system-x86_64 \
15704 -net user -net nic,model=virtio \
15705 -enable-kvm -m 256 /tmp/qemu-image
15708 Here is what each of these options means:
15711 @item qemu-system-x86_64
15712 This specifies the hardware platform to emulate. This should match the
15716 Enable the unprivileged user-mode network stack. The guest OS can
15717 access the host but not vice versa. This is the simplest way to get the
15720 @item -net nic,model=virtio
15721 You must create a network interface of a given model. If you do not
15722 create a NIC, the boot will fail. Assuming your hardware platform is
15723 x86_64, you can get a list of available NIC models by running
15724 @command{qemu-system-x86_64 -net nic,model=help}.
15727 If your system has hardware virtualization extensions, enabling the
15728 virtual machine support (KVM) of the Linux kernel will make things run
15732 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
15733 which may be insufficient for some operations.
15735 @item /tmp/qemu-image
15736 The file name of the qcow2 image.
15739 The default @command{run-vm.sh} script that is returned by an invocation of
15740 @command{guix system vm} does not add a @command{-net user} flag by default.
15741 To get network access from within the vm add the @code{(dhcp-client-service)}
15742 to your system definition and start the VM using
15743 @command{`guix system vm config.scm` -net user}. An important caveat of using
15744 @command{-net user} for networking is that @command{ping} will not work, because
15745 it uses the ICMP protocol. You'll have to use a different command to check for
15746 network connectivity, for example @command{guix download}.
15748 @subsubsection Connecting Through SSH
15752 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
15753 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
15754 boot unsupervised. It requires you to type some characters to initialize the
15755 randomness generator. In addition you need to forward the SSH port, 22 by
15756 default, to the host. You can do this with
15759 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
15762 To connect to the VM you can run
15765 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
15768 The @command{-p} tells @command{ssh} the port you want to connect to.
15769 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
15770 every time you modify your @command{config.scm} file and the
15771 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
15772 connection to an unknown host every time you connect.
15774 @subsubsection Using @command{virt-viewer} with Spice
15776 As an alternative to the default @command{qemu} graphical client you can
15777 use the @command{remote-viewer} from the @command{virt-viewer} package. To
15778 connect pass the @command{-spice port=5930,disable-ticketing} flag to
15779 @command{qemu}. See previous section for further information on how to do this.
15781 Spice also allows you to do some nice stuff like share your clipboard with your
15782 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
15785 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
15786 -chardev spicevmc,name=vdagent,id=vdagent
15787 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
15788 name=com.redhat.spice.0
15791 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
15793 @node Defining Services
15794 @subsection Defining Services
15796 The previous sections show the available services and how one can combine
15797 them in an @code{operating-system} declaration. But how do we define
15798 them in the first place? And what is a service anyway?
15801 * Service Composition:: The model for composing services.
15802 * Service Types and Services:: Types and services.
15803 * Service Reference:: API reference.
15804 * Shepherd Services:: A particular type of service.
15807 @node Service Composition
15808 @subsubsection Service Composition
15812 Here we define a @dfn{service} as, broadly, something that extends the
15813 functionality of the operating system. Often a service is a process---a
15814 @dfn{daemon}---started when the system boots: a secure shell server, a
15815 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
15816 whose execution can be triggered by another daemon---e.g., an FTP server
15817 started by @command{inetd} or a D-Bus service activated by
15818 @command{dbus-daemon}. Occasionally, a service does not map to a
15819 daemon. For instance, the ``account'' service collects user accounts
15820 and makes sure they exist when the system runs; the ``udev'' service
15821 collects device management rules and makes them available to the eudev
15822 daemon; the @file{/etc} service populates the @file{/etc} directory
15825 @cindex service extensions
15826 GuixSD services are connected by @dfn{extensions}. For instance, the
15827 secure shell service @emph{extends} the Shepherd---the GuixSD
15828 initialization system, running as PID@tie{}1---by giving it the command
15829 lines to start and stop the secure shell daemon (@pxref{Networking
15830 Services, @code{lsh-service}}); the UPower service extends the D-Bus
15831 service by passing it its @file{.service} specification, and extends the
15832 udev service by passing it device management rules (@pxref{Desktop
15833 Services, @code{upower-service}}); the Guix daemon service extends the
15834 Shepherd by passing it the command lines to start and stop the daemon,
15835 and extends the account service by passing it a list of required build
15836 user accounts (@pxref{Base Services}).
15838 All in all, services and their ``extends'' relations form a directed
15839 acyclic graph (DAG). If we represent services as boxes and extensions
15840 as arrows, a typical system might provide something like this:
15842 @image{images/service-graph,,5in,Typical service extension graph.}
15844 @cindex system service
15845 At the bottom, we see the @dfn{system service}, which produces the
15846 directory containing everything to run and boot the system, as returned
15847 by the @command{guix system build} command. @xref{Service Reference},
15848 to learn about the other service types shown here.
15849 @xref{system-extension-graph, the @command{guix system extension-graph}
15850 command}, for information on how to generate this representation for a
15851 particular operating system definition.
15853 @cindex service types
15854 Technically, developers can define @dfn{service types} to express these
15855 relations. There can be any number of services of a given type on the
15856 system---for instance, a system running two instances of the GNU secure
15857 shell server (lsh) has two instances of @var{lsh-service-type}, with
15858 different parameters.
15860 The following section describes the programming interface for service
15861 types and services.
15863 @node Service Types and Services
15864 @subsubsection Service Types and Services
15866 A @dfn{service type} is a node in the DAG described above. Let us start
15867 with a simple example, the service type for the Guix build daemon
15868 (@pxref{Invoking guix-daemon}):
15871 (define guix-service-type
15875 (list (service-extension shepherd-root-service-type guix-shepherd-service)
15876 (service-extension account-service-type guix-accounts)
15877 (service-extension activation-service-type guix-activation)))
15878 (default-value (guix-configuration))))
15882 It defines three things:
15886 A name, whose sole purpose is to make inspection and debugging easier.
15889 A list of @dfn{service extensions}, where each extension designates the
15890 target service type and a procedure that, given the parameters of the
15891 service, returns a list of objects to extend the service of that type.
15893 Every service type has at least one service extension. The only
15894 exception is the @dfn{boot service type}, which is the ultimate service.
15897 Optionally, a default value for instances of this type.
15900 In this example, @var{guix-service-type} extends three services:
15903 @item shepherd-root-service-type
15904 The @var{guix-shepherd-service} procedure defines how the Shepherd
15905 service is extended. Namely, it returns a @code{<shepherd-service>}
15906 object that defines how @command{guix-daemon} is started and stopped
15907 (@pxref{Shepherd Services}).
15909 @item account-service-type
15910 This extension for this service is computed by @var{guix-accounts},
15911 which returns a list of @code{user-group} and @code{user-account}
15912 objects representing the build user accounts (@pxref{Invoking
15915 @item activation-service-type
15916 Here @var{guix-activation} is a procedure that returns a gexp, which is
15917 a code snippet to run at ``activation time''---e.g., when the service is
15921 A service of this type is instantiated like this:
15924 (service guix-service-type
15925 (guix-configuration
15927 (use-substitutes? #f)))
15930 The second argument to the @code{service} form is a value representing
15931 the parameters of this specific service instance.
15932 @xref{guix-configuration-type, @code{guix-configuration}}, for
15933 information about the @code{guix-configuration} data type. When the
15934 value is omitted, the default value specified by
15935 @code{guix-service-type} is used:
15938 (service guix-service-type)
15941 @var{guix-service-type} is quite simple because it extends other
15942 services but is not extensible itself.
15944 @c @subsubsubsection Extensible Service Types
15946 The service type for an @emph{extensible} service looks like this:
15949 (define udev-service-type
15950 (service-type (name 'udev)
15952 (list (service-extension shepherd-root-service-type
15953 udev-shepherd-service)))
15955 (compose concatenate) ;concatenate the list of rules
15956 (extend (lambda (config rules)
15958 (($ <udev-configuration> udev initial-rules)
15959 (udev-configuration
15960 (udev udev) ;the udev package to use
15961 (rules (append initial-rules rules)))))))))
15964 This is the service type for the
15965 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
15966 management daemon}. Compared to the previous example, in addition to an
15967 extension of @var{shepherd-root-service-type}, we see two new fields:
15971 This is the procedure to @dfn{compose} the list of extensions to
15972 services of this type.
15974 Services can extend the udev service by passing it lists of rules; we
15975 compose those extensions simply by concatenating them.
15978 This procedure defines how the value of the service is @dfn{extended} with
15979 the composition of the extensions.
15981 Udev extensions are composed into a list of rules, but the udev service
15982 value is itself a @code{<udev-configuration>} record. So here, we
15983 extend that record by appending the list of rules it contains to the
15984 list of contributed rules.
15987 There can be only one instance of an extensible service type such as
15988 @var{udev-service-type}. If there were more, the
15989 @code{service-extension} specifications would be ambiguous.
15991 Still here? The next section provides a reference of the programming
15992 interface for services.
15994 @node Service Reference
15995 @subsubsection Service Reference
15997 We have seen an overview of service types (@pxref{Service Types and
15998 Services}). This section provides a reference on how to manipulate
15999 services and service types. This interface is provided by the
16000 @code{(gnu services)} module.
16002 @deffn {Scheme Procedure} service @var{type} [@var{value}]
16003 Return a new service of @var{type}, a @code{<service-type>} object (see
16004 below.) @var{value} can be any object; it represents the parameters of
16005 this particular service instance.
16007 When @var{value} is omitted, the default value specified by @var{type}
16008 is used; if @var{type} does not specify a default value, an error is
16011 For instance, this:
16014 (service openssh-service-type)
16018 is equivalent to this:
16021 (service openssh-service-type
16022 (openssh-configuration))
16025 In both cases the result is an instance of @code{openssh-service-type}
16026 with the default configuration.
16029 @deffn {Scheme Procedure} service? @var{obj}
16030 Return true if @var{obj} is a service.
16033 @deffn {Scheme Procedure} service-kind @var{service}
16034 Return the type of @var{service}---i.e., a @code{<service-type>} object.
16037 @deffn {Scheme Procedure} service-value @var{service}
16038 Return the value associated with @var{service}. It represents its
16042 Here is an example of how a service is created and manipulated:
16046 (service nginx-service-type
16047 (nginx-configuration
16049 (log-directory log-directory)
16050 (run-directory run-directory)
16051 (file config-file))))
16056 (eq? (service-kind s) nginx-service-type)
16060 The @code{modify-services} form provides a handy way to change the
16061 parameters of some of the services of a list such as
16062 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
16063 evaluates to a list of services. Of course, you could always use
16064 standard list combinators such as @code{map} and @code{fold} to do that
16065 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
16066 @code{modify-services} simply provides a more concise form for this
16069 @deffn {Scheme Syntax} modify-services @var{services} @
16070 (@var{type} @var{variable} => @var{body}) @dots{}
16072 Modify the services listed in @var{services} according to the given
16073 clauses. Each clause has the form:
16076 (@var{type} @var{variable} => @var{body})
16079 where @var{type} is a service type---e.g.,
16080 @code{guix-service-type}---and @var{variable} is an identifier that is
16081 bound within the @var{body} to the service parameters---e.g., a
16082 @code{guix-configuration} instance---of the original service of that
16085 The @var{body} should evaluate to the new service parameters, which will
16086 be used to configure the new service. This new service will replace the
16087 original in the resulting list. Because a service's service parameters
16088 are created using @code{define-record-type*}, you can write a succinct
16089 @var{body} that evaluates to the new service parameters by using the
16090 @code{inherit} feature that @code{define-record-type*} provides.
16092 @xref{Using the Configuration System}, for example usage.
16096 Next comes the programming interface for service types. This is
16097 something you want to know when writing new service definitions, but not
16098 necessarily when simply looking for ways to customize your
16099 @code{operating-system} declaration.
16101 @deftp {Data Type} service-type
16102 @cindex service type
16103 This is the representation of a @dfn{service type} (@pxref{Service Types
16108 This is a symbol, used only to simplify inspection and debugging.
16110 @item @code{extensions}
16111 A non-empty list of @code{<service-extension>} objects (see below).
16113 @item @code{compose} (default: @code{#f})
16114 If this is @code{#f}, then the service type denotes services that cannot
16115 be extended---i.e., services that do not receive ``values'' from other
16118 Otherwise, it must be a one-argument procedure. The procedure is called
16119 by @code{fold-services} and is passed a list of values collected from
16120 extensions. It must return a value that is a valid parameter value for
16121 the service instance.
16123 @item @code{extend} (default: @code{#f})
16124 If this is @code{#f}, services of this type cannot be extended.
16126 Otherwise, it must be a two-argument procedure: @code{fold-services}
16127 calls it, passing it the initial value of the service as the first argument
16128 and the result of applying @code{compose} to the extension values as the
16132 @xref{Service Types and Services}, for examples.
16135 @deffn {Scheme Procedure} service-extension @var{target-type} @
16137 Return a new extension for services of type @var{target-type}.
16138 @var{compute} must be a one-argument procedure: @code{fold-services}
16139 calls it, passing it the value associated with the service that provides
16140 the extension; it must return a valid value for the target service.
16143 @deffn {Scheme Procedure} service-extension? @var{obj}
16144 Return true if @var{obj} is a service extension.
16147 Occasionally, you might want to simply extend an existing service. This
16148 involves creating a new service type and specifying the extension of
16149 interest, which can be verbose; the @code{simple-service} procedure
16150 provides a shorthand for this.
16152 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16153 Return a service that extends @var{target} with @var{value}. This works
16154 by creating a singleton service type @var{name}, of which the returned
16155 service is an instance.
16157 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16161 (simple-service 'my-mcron-job mcron-service-type
16162 #~(job '(next-hour (3)) "guix gc -F 2G"))
16166 At the core of the service abstraction lies the @code{fold-services}
16167 procedure, which is responsible for ``compiling'' a list of services
16168 down to a single directory that contains everything needed to boot and
16169 run the system---the directory shown by the @command{guix system build}
16170 command (@pxref{Invoking guix system}). In essence, it propagates
16171 service extensions down the service graph, updating each node parameters
16172 on the way, until it reaches the root node.
16174 @deffn {Scheme Procedure} fold-services @var{services} @
16175 [#:target-type @var{system-service-type}]
16176 Fold @var{services} by propagating their extensions down to the root of
16177 type @var{target-type}; return the root service adjusted accordingly.
16180 Lastly, the @code{(gnu services)} module also defines several essential
16181 service types, some of which are listed below.
16183 @defvr {Scheme Variable} system-service-type
16184 This is the root of the service graph. It produces the system directory
16185 as returned by the @command{guix system build} command.
16188 @defvr {Scheme Variable} boot-service-type
16189 The type of the ``boot service'', which produces the @dfn{boot script}.
16190 The boot script is what the initial RAM disk runs when booting.
16193 @defvr {Scheme Variable} etc-service-type
16194 The type of the @file{/etc} service. This service can be extended by
16195 passing it name/file tuples such as:
16198 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16201 In this example, the effect would be to add an @file{/etc/issue} file
16202 pointing to the given file.
16205 @defvr {Scheme Variable} setuid-program-service-type
16206 Type for the ``setuid-program service''. This service collects lists of
16207 executable file names, passed as gexps, and adds them to the set of
16208 setuid-root programs on the system (@pxref{Setuid Programs}).
16211 @defvr {Scheme Variable} profile-service-type
16212 Type of the service that populates the @dfn{system profile}---i.e., the
16213 programs under @file{/run/current-system/profile}. Other services can
16214 extend it by passing it lists of packages to add to the system profile.
16218 @node Shepherd Services
16219 @subsubsection Shepherd Services
16221 @cindex shepherd services
16223 @cindex init system
16224 The @code{(gnu services shepherd)} module provides a way to define
16225 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16226 initialization system---the first process that is started when the
16227 system boots, also known as PID@tie{}1
16228 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16230 Services in the Shepherd can depend on each other. For instance, the
16231 SSH daemon may need to be started after the syslog daemon has been
16232 started, which in turn can only happen once all the file systems have
16233 been mounted. The simple operating system defined earlier (@pxref{Using
16234 the Configuration System}) results in a service graph like this:
16236 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16238 You can actually generate such a graph for any operating system
16239 definition using the @command{guix system shepherd-graph} command
16240 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16242 The @var{%shepherd-root-service} is a service object representing
16243 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16244 by passing it lists of @code{<shepherd-service>} objects.
16246 @deftp {Data Type} shepherd-service
16247 The data type representing a service managed by the Shepherd.
16250 @item @code{provision}
16251 This is a list of symbols denoting what the service provides.
16253 These are the names that may be passed to @command{herd start},
16254 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16255 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16256 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16258 @item @code{requirements} (default: @code{'()})
16259 List of symbols denoting the Shepherd services this one depends on.
16261 @item @code{respawn?} (default: @code{#t})
16262 Whether to restart the service when it stops, for instance when the
16263 underlying process dies.
16266 @itemx @code{stop} (default: @code{#~(const #f)})
16267 The @code{start} and @code{stop} fields refer to the Shepherd's
16268 facilities to start and stop processes (@pxref{Service De- and
16269 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16270 G-expressions that get expanded in the Shepherd configuration file
16271 (@pxref{G-Expressions}).
16273 @item @code{documentation}
16274 A documentation string, as shown when running:
16277 herd doc @var{service-name}
16280 where @var{service-name} is one of the symbols in @var{provision}
16281 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16283 @item @code{modules} (default: @var{%default-modules})
16284 This is the list of modules that must be in scope when @code{start} and
16285 @code{stop} are evaluated.
16290 @defvr {Scheme Variable} shepherd-root-service-type
16291 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16293 This is the service type that extensions target when they want to create
16294 shepherd services (@pxref{Service Types and Services}, for an example).
16295 Each extension must pass a list of @code{<shepherd-service>}.
16298 @defvr {Scheme Variable} %shepherd-root-service
16299 This service represents PID@tie{}1.
16303 @node Documentation
16304 @section Documentation
16306 @cindex documentation, searching for
16307 @cindex searching for documentation
16308 @cindex Info, documentation format
16310 @cindex manual pages
16311 In most cases packages installed with Guix come with documentation.
16312 There are two main documentation formats: ``Info'', a browseable
16313 hypertext format used for GNU software, and ``manual pages'' (or ``man
16314 pages''), the linear documentation format traditionally found on Unix.
16315 Info manuals are accessed with the @command{info} command or with Emacs,
16316 and man pages are accessed using @command{man}.
16318 You can look for documentation of software installed on your system by
16319 keyword. For example, the following command searches for information
16320 about ``TLS'' in Info manuals:
16324 "(emacs)Network Security" -- STARTTLS
16325 "(emacs)Network Security" -- TLS
16326 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16327 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16332 The command below searches for the same keyword in man pages:
16336 SSL (7) - OpenSSL SSL/TLS library
16337 certtool (1) - GnuTLS certificate tool
16341 These searches are purely local to your computer so you have the
16342 guarantee that documentation you find corresponds to what you have
16343 actually installed, you can access it off-line, and your privacy is
16346 Once you have these results, you can view the relevant documentation by
16350 $ info "(gnutls)Core TLS API"
16360 Info manuals contain sections and indices as well as hyperlinks like
16361 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16362 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16363 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16364 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16365 Introduction}, for an introduction to Info navigation.
16367 @node Installing Debugging Files
16368 @section Installing Debugging Files
16370 @cindex debugging files
16371 Program binaries, as produced by the GCC compilers for instance, are
16372 typically written in the ELF format, with a section containing
16373 @dfn{debugging information}. Debugging information is what allows the
16374 debugger, GDB, to map binary code to source code; it is required to
16375 debug a compiled program in good conditions.
16377 The problem with debugging information is that is takes up a fair amount
16378 of disk space. For example, debugging information for the GNU C Library
16379 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16380 debugging info of all the installed programs is usually not an option.
16381 Yet, space savings should not come at the cost of an impediment to
16382 debugging---especially in the GNU system, which should make it easier
16383 for users to exert their computing freedom (@pxref{GNU Distribution}).
16385 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16386 mechanism that allows users to get the best of both worlds: debugging
16387 information can be stripped from the binaries and stored in separate
16388 files. GDB is then able to load debugging information from those files,
16389 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16392 The GNU distribution takes advantage of this by storing debugging
16393 information in the @code{lib/debug} sub-directory of a separate package
16394 output unimaginatively called @code{debug} (@pxref{Packages with
16395 Multiple Outputs}). Users can choose to install the @code{debug} output
16396 of a package when they need it. For instance, the following command
16397 installs the debugging information for the GNU C Library and for GNU
16401 guix package -i glibc:debug guile:debug
16404 GDB must then be told to look for debug files in the user's profile, by
16405 setting the @code{debug-file-directory} variable (consider setting it
16406 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16410 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16413 From there on, GDB will pick up debugging information from the
16414 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16416 In addition, you will most likely want GDB to be able to show the source
16417 code being debugged. To do that, you will have to unpack the source
16418 code of the package of interest (obtained with @code{guix build
16419 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16420 directory using the @code{directory} command (@pxref{Source Path,
16421 @code{directory},, gdb, Debugging with GDB}).
16423 @c XXX: keep me up-to-date
16424 The @code{debug} output mechanism in Guix is implemented by the
16425 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16426 opt-in---debugging information is available only for the packages
16427 with definitions explicitly declaring a @code{debug} output. This may be
16428 changed to opt-out in the future if our build farm servers can handle
16429 the load. To check whether a package has a @code{debug} output, use
16430 @command{guix package --list-available} (@pxref{Invoking guix package}).
16433 @node Security Updates
16434 @section Security Updates
16436 @cindex security updates
16437 @cindex security vulnerabilities
16438 Occasionally, important security vulnerabilities are discovered in software
16439 packages and must be patched. Guix developers try hard to keep track of
16440 known vulnerabilities and to apply fixes as soon as possible in the
16441 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16442 containing only security updates.) The @command{guix lint} tool helps
16443 developers find out about vulnerable versions of software packages in the
16448 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16449 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
16450 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16454 @xref{Invoking guix lint}, for more information.
16457 As of version @value{VERSION}, the feature described below is considered
16461 Guix follows a functional
16462 package management discipline (@pxref{Introduction}), which implies
16463 that, when a package is changed, @emph{every package that depends on it}
16464 must be rebuilt. This can significantly slow down the deployment of
16465 fixes in core packages such as libc or Bash, since basically the whole
16466 distribution would need to be rebuilt. Using pre-built binaries helps
16467 (@pxref{Substitutes}), but deployment may still take more time than
16471 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16472 for fast deployment of critical updates without the costs associated
16473 with a whole-distribution rebuild. The idea is to rebuild only the
16474 package that needs to be patched, and then to ``graft'' it onto packages
16475 explicitly installed by the user and that were previously referring to
16476 the original package. The cost of grafting is typically very low, and
16477 order of magnitudes lower than a full rebuild of the dependency chain.
16479 @cindex replacements of packages, for grafts
16480 For instance, suppose a security update needs to be applied to Bash.
16481 Guix developers will provide a package definition for the ``fixed''
16482 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16483 Packages}). Then, the original package definition is augmented with a
16484 @code{replacement} field pointing to the package containing the bug fix:
16491 (replacement bash-fixed)))
16494 From there on, any package depending directly or indirectly on Bash---as
16495 reported by @command{guix gc --requisites} (@pxref{Invoking guix
16496 gc})---that is installed is automatically ``rewritten'' to refer to
16497 @var{bash-fixed} instead of @var{bash}. This grafting process takes
16498 time proportional to the size of the package, usually less than a
16499 minute for an ``average'' package on a recent machine. Grafting is
16500 recursive: when an indirect dependency requires grafting, then grafting
16501 ``propagates'' up to the package that the user is installing.
16503 Currently, the length of the name and version of the graft and that of
16504 the package it replaces (@var{bash-fixed} and @var{bash} in the example
16505 above) must be equal. This restriction mostly comes from the fact that
16506 grafting works by patching files, including binary files, directly.
16507 Other restrictions may apply: for instance, when adding a graft to a
16508 package providing a shared library, the original shared library and its
16509 replacement must have the same @code{SONAME} and be binary-compatible.
16511 The @option{--no-grafts} command-line option allows you to forcefully
16512 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
16516 guix build bash --no-grafts
16520 returns the store file name of the original Bash, whereas:
16527 returns the store file name of the ``fixed'', replacement Bash. This
16528 allows you to distinguish between the two variants of Bash.
16530 To verify which Bash your whole profile refers to, you can run
16531 (@pxref{Invoking guix gc}):
16534 guix gc -R `readlink -f ~/.guix-profile` | grep bash
16538 @dots{} and compare the store file names that you get with those above.
16539 Likewise for a complete GuixSD system generation:
16542 guix gc -R `guix system build my-config.scm` | grep bash
16545 Lastly, to check which Bash running processes are using, you can use the
16546 @command{lsof} command:
16549 lsof | grep /gnu/store/.*bash
16553 @node Package Modules
16554 @section Package Modules
16556 From a programming viewpoint, the package definitions of the
16557 GNU distribution are provided by Guile modules in the @code{(gnu packages
16558 @dots{})} name space@footnote{Note that packages under the @code{(gnu
16559 packages @dots{})} module name space are not necessarily ``GNU
16560 packages''. This module naming scheme follows the usual Guile module
16561 naming convention: @code{gnu} means that these modules are distributed
16562 as part of the GNU system, and @code{packages} identifies modules that
16563 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
16564 Reference Manual}). For instance, the @code{(gnu packages emacs)}
16565 module exports a variable named @code{emacs}, which is bound to a
16566 @code{<package>} object (@pxref{Defining Packages}).
16568 The @code{(gnu packages @dots{})} module name space is
16569 automatically scanned for packages by the command-line tools. For
16570 instance, when running @code{guix package -i emacs}, all the @code{(gnu
16571 packages @dots{})} modules are scanned until one that exports a package
16572 object whose name is @code{emacs} is found. This package search
16573 facility is implemented in the @code{(gnu packages)} module.
16575 @cindex customization, of packages
16576 @cindex package module search path
16577 Users can store package definitions in modules with different
16578 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
16579 name and module name must match. For instance, the @code{(my-packages
16580 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
16581 relative to the load path specified with @option{--load-path} or
16582 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
16583 guile, GNU Guile Reference Manual}, for details.}. These package definitions
16584 will not be visible by default. Users can invoke commands such as
16585 @command{guix package} and @command{guix build} with the
16586 @code{-e} option so that they know where to find the package. Better
16587 yet, they can use the
16588 @code{-L} option of these commands to make those modules visible
16589 (@pxref{Invoking guix build, @code{--load-path}}), or define the
16590 @code{GUIX_PACKAGE_PATH} environment variable. This environment
16591 variable makes it easy to extend or customize the distribution and is
16592 honored by all the user interfaces.
16594 @defvr {Environment Variable} GUIX_PACKAGE_PATH
16595 This is a colon-separated list of directories to search for additional
16596 package modules. Directories listed in this variable take precedence
16597 over the own modules of the distribution.
16600 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
16601 each package is built based solely on other packages in the
16602 distribution. The root of this dependency graph is a small set of
16603 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
16604 bootstrap)} module. For more information on bootstrapping,
16605 @pxref{Bootstrapping}.
16607 @node Packaging Guidelines
16608 @section Packaging Guidelines
16610 @cindex packages, creating
16611 The GNU distribution is nascent and may well lack some of your favorite
16612 packages. This section describes how you can help make the distribution
16613 grow. @xref{Contributing}, for additional information on how you can
16616 Free software packages are usually distributed in the form of
16617 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
16618 all the source files. Adding a package to the distribution means
16619 essentially two things: adding a @dfn{recipe} that describes how to
16620 build the package, including a list of other packages required to build
16621 it, and adding @dfn{package metadata} along with that recipe, such as a
16622 description and licensing information.
16624 In Guix all this information is embodied in @dfn{package definitions}.
16625 Package definitions provide a high-level view of the package. They are
16626 written using the syntax of the Scheme programming language; in fact,
16627 for each package we define a variable bound to the package definition,
16628 and export that variable from a module (@pxref{Package Modules}).
16629 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
16630 creating packages. For more information on package definitions,
16631 @pxref{Defining Packages}.
16633 Once a package definition is in place, stored in a file in the Guix
16634 source tree, it can be tested using the @command{guix build} command
16635 (@pxref{Invoking guix build}). For example, assuming the new package is
16636 called @code{gnew}, you may run this command from the Guix build tree
16637 (@pxref{Running Guix Before It Is Installed}):
16640 ./pre-inst-env guix build gnew --keep-failed
16643 Using @code{--keep-failed} makes it easier to debug build failures since
16644 it provides access to the failed build tree. Another useful
16645 command-line option when debugging is @code{--log-file}, to access the
16648 If the package is unknown to the @command{guix} command, it may be that
16649 the source file contains a syntax error, or lacks a @code{define-public}
16650 clause to export the package variable. To figure it out, you may load
16651 the module from Guile to get more information about the actual error:
16654 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
16657 Once your package builds correctly, please send us a patch
16658 (@pxref{Contributing}). Well, if you need help, we will be happy to
16659 help you too. Once the patch is committed in the Guix repository, the
16660 new package automatically gets built on the supported platforms by
16661 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
16664 @cindex substituter
16665 Users can obtain the new package definition simply by running
16666 @command{guix pull} (@pxref{Invoking guix pull}). When
16667 @code{hydra.gnu.org} is done building the package, installing the
16668 package automatically downloads binaries from there
16669 (@pxref{Substitutes}). The only place where human intervention is
16670 needed is to review and apply the patch.
16674 * Software Freedom:: What may go into the distribution.
16675 * Package Naming:: What's in a name?
16676 * Version Numbers:: When the name is not enough.
16677 * Synopses and Descriptions:: Helping users find the right package.
16678 * Python Modules:: A touch of British comedy.
16679 * Perl Modules:: Little pearls.
16680 * Java Packages:: Coffee break.
16681 * Fonts:: Fond of fonts.
16684 @node Software Freedom
16685 @subsection Software Freedom
16687 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
16688 @cindex free software
16689 The GNU operating system has been developed so that users can have
16690 freedom in their computing. GNU is @dfn{free software}, meaning that
16691 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
16692 essential freedoms}: to run the program, to study and change the program
16693 in source code form, to redistribute exact copies, and to distribute
16694 modified versions. Packages found in the GNU distribution provide only
16695 software that conveys these four freedoms.
16697 In addition, the GNU distribution follow the
16698 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
16699 software distribution guidelines}. Among other things, these guidelines
16700 reject non-free firmware, recommendations of non-free software, and
16701 discuss ways to deal with trademarks and patents.
16703 Some otherwise free upstream package sources contain a small and optional
16704 subset that violates the above guidelines, for instance because this subset
16705 is itself non-free code. When that happens, the offending items are removed
16706 with appropriate patches or code snippets in the @code{origin} form of the
16707 package (@pxref{Defining Packages}). This way, @code{guix
16708 build --source} returns the ``freed'' source rather than the unmodified
16712 @node Package Naming
16713 @subsection Package Naming
16715 @cindex package name
16716 A package has actually two names associated with it:
16717 First, there is the name of the @emph{Scheme variable}, the one following
16718 @code{define-public}. By this name, the package can be made known in the
16719 Scheme code, for instance as input to another package. Second, there is
16720 the string in the @code{name} field of a package definition. This name
16721 is used by package management commands such as
16722 @command{guix package} and @command{guix build}.
16724 Both are usually the same and correspond to the lowercase conversion of
16725 the project name chosen upstream, with underscores replaced with
16726 hyphens. For instance, GNUnet is available as @code{gnunet}, and
16727 SDL_net as @code{sdl-net}.
16729 We do not add @code{lib} prefixes for library packages, unless these are
16730 already part of the official project name. But @pxref{Python
16731 Modules} and @ref{Perl Modules} for special rules concerning modules for
16732 the Python and Perl languages.
16734 Font package names are handled differently, @pxref{Fonts}.
16737 @node Version Numbers
16738 @subsection Version Numbers
16740 @cindex package version
16741 We usually package only the latest version of a given free software
16742 project. But sometimes, for instance for incompatible library versions,
16743 two (or more) versions of the same package are needed. These require
16744 different Scheme variable names. We use the name as defined
16745 in @ref{Package Naming}
16746 for the most recent version; previous versions use the same name, suffixed
16747 by @code{-} and the smallest prefix of the version number that may
16748 distinguish the two versions.
16750 The name inside the package definition is the same for all versions of a
16751 package and does not contain any version number.
16753 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
16756 (define-public gtk+
16761 (define-public gtk+-2
16764 (version "2.24.20")
16767 If we also wanted GTK+ 3.8.2, this would be packaged as
16769 (define-public gtk+-3.8
16776 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
16777 @c for a discussion of what follows.
16778 @cindex version number, for VCS snapshots
16779 Occasionally, we package snapshots of upstream's version control system
16780 (VCS) instead of formal releases. This should remain exceptional,
16781 because it is up to upstream developers to clarify what the stable
16782 release is. Yet, it is sometimes necessary. So, what should we put in
16783 the @code{version} field?
16785 Clearly, we need to make the commit identifier of the VCS snapshot
16786 visible in the version string, but we also need to make sure that the
16787 version string is monotonically increasing so that @command{guix package
16788 --upgrade} can determine which version is newer. Since commit
16789 identifiers, notably with Git, are not monotonically increasing, we add
16790 a revision number that we increase each time we upgrade to a newer
16791 snapshot. The resulting version string looks like this:
16796 | | `-- upstream commit ID
16798 | `--- Guix package revision
16800 latest upstream version
16803 It is a good idea to strip commit identifiers in the @code{version}
16804 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
16805 aesthetics have a role to play here) as well as problems related to OS
16806 limits such as the maximum shebang length (127 bytes for the Linux
16807 kernel.) It is best to use the full commit identifiers in
16808 @code{origin}s, though, to avoid ambiguities. A typical package
16809 definition may look like this:
16813 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
16814 (revision "1")) ;Guix package revision
16816 (version (string-append "0.9-" revision "."
16817 (string-take commit 7)))
16820 (uri (git-reference
16821 (url "git://example.org/my-package.git")
16823 (sha256 (base32 "1mbikn@dots{}"))
16824 (file-name (string-append "my-package-" version
16830 @node Synopses and Descriptions
16831 @subsection Synopses and Descriptions
16833 @cindex package description
16834 @cindex package synopsis
16835 As we have seen before, each package in GNU@tie{}Guix includes a
16836 synopsis and a description (@pxref{Defining Packages}). Synopses and
16837 descriptions are important: They are what @command{guix package
16838 --search} searches, and a crucial piece of information to help users
16839 determine whether a given package suits their needs. Consequently,
16840 packagers should pay attention to what goes into them.
16842 Synopses must start with a capital letter and must not end with a
16843 period. They must not start with ``a'' or ``the'', which usually does
16844 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
16845 tool that frobs files''. The synopsis should say what the package
16846 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
16847 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
16848 matching a pattern''.
16850 Keep in mind that the synopsis must be meaningful for a very wide
16851 audience. For example, ``Manipulate alignments in the SAM format''
16852 might make sense for a seasoned bioinformatics researcher, but might be
16853 fairly unhelpful or even misleading to a non-specialized audience. It
16854 is a good idea to come up with a synopsis that gives an idea of the
16855 application domain of the package. In this example, this might give
16856 something like ``Manipulate nucleotide sequence alignments'', which
16857 hopefully gives the user a better idea of whether this is what they are
16860 Descriptions should take between five and ten lines. Use full
16861 sentences, and avoid using acronyms without first introducing them.
16862 Please avoid marketing phrases such as ``world-leading'',
16863 ``industrial-strength'', and ``next-generation'', and avoid superlatives
16864 like ``the most advanced''---they are not helpful to users looking for a
16865 package and may even sound suspicious. Instead, try to be factual,
16866 mentioning use cases and features.
16868 @cindex Texinfo markup, in package descriptions
16869 Descriptions can include Texinfo markup, which is useful to introduce
16870 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
16871 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
16872 should be careful when using some characters for example @samp{@@} and
16873 curly braces which are the basic special characters in Texinfo
16874 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
16875 such as @command{guix package --show} take care of rendering it
16878 Synopses and descriptions are translated by volunteers
16879 @uref{http://translationproject.org/domain/guix-packages.html, at the
16880 Translation Project} so that as many users as possible can read them in
16881 their native language. User interfaces search them and display them in
16882 the language specified by the current locale.
16884 Translation is a lot of work so, as a packager, please pay even more
16885 attention to your synopses and descriptions as every change may entail
16886 additional work for translators. In order to help them, it is possible
16887 to make recommendations or instructions visible to them by inserting
16888 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
16892 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
16893 (description "ARandR is designed to provide a simple visual front end
16894 for the X11 resize-and-rotate (RandR) extension. @dots{}")
16898 @node Python Modules
16899 @subsection Python Modules
16902 We currently package Python 2 and Python 3, under the Scheme variable names
16903 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
16904 To avoid confusion and naming clashes with other programming languages, it
16905 seems desirable that the name of a package for a Python module contains
16906 the word @code{python}.
16908 Some modules are compatible with only one version of Python, others with both.
16909 If the package Foo compiles only with Python 3, we name it
16910 @code{python-foo}; if it compiles only with Python 2, we name it
16911 @code{python2-foo}. If it is compatible with both versions, we create two
16912 packages with the corresponding names.
16914 If a project already contains the word @code{python}, we drop this;
16915 for instance, the module python-dateutil is packaged under the names
16916 @code{python-dateutil} and @code{python2-dateutil}. If the project name
16917 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
16920 @subsubsection Specifying Dependencies
16921 @cindex inputs, for Python packages
16923 Dependency information for Python packages is usually available in the
16924 package source tree, with varying degrees of accuracy: in the
16925 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
16927 Your mission, when writing a recipe for a Python package, is to map
16928 these dependencies to the appropriate type of ``input'' (@pxref{package
16929 Reference, inputs}). Although the @code{pypi} importer normally does a
16930 good job (@pxref{Invoking guix import}), you may want to check the
16931 following check list to determine which dependency goes where.
16936 We currently package Python 2 with @code{setuptools} and @code{pip}
16937 installed like Python 3.4 has per default. Thus you don't need to
16938 specify either of these as an input. @command{guix lint} will warn you
16942 Python dependencies required at run time go into
16943 @code{propagated-inputs}. They are typically defined with the
16944 @code{install_requires} keyword in @file{setup.py}, or in the
16945 @file{requirements.txt} file.
16948 Python packages required only at build time---e.g., those listed with
16949 the @code{setup_requires} keyword in @file{setup.py}---or only for
16950 testing---e.g., those in @code{tests_require}---go into
16951 @code{native-inputs}. The rationale is that (1) they do not need to be
16952 propagated because they are not needed at run time, and (2) in a
16953 cross-compilation context, it's the ``native'' input that we'd want.
16955 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
16956 frameworks. Of course if any of these packages is also required at
16957 run-time, it needs to go to @code{propagated-inputs}.
16960 Anything that does not fall in the previous categories goes to
16961 @code{inputs}, for example programs or C libraries required for building
16962 Python packages containing C extensions.
16965 If a Python package has optional dependencies (@code{extras_require}),
16966 it is up to you to decide whether to add them or not, based on their
16967 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
16974 @subsection Perl Modules
16977 Perl programs standing for themselves are named as any other package,
16978 using the lowercase upstream name.
16979 For Perl packages containing a single class, we use the lowercase class name,
16980 replace all occurrences of @code{::} by dashes and prepend the prefix
16982 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
16983 Modules containing several classes keep their lowercase upstream name and
16984 are also prepended by @code{perl-}. Such modules tend to have the word
16985 @code{perl} somewhere in their name, which gets dropped in favor of the
16986 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
16989 @node Java Packages
16990 @subsection Java Packages
16993 Java programs standing for themselves are named as any other package,
16994 using the lowercase upstream name.
16996 To avoid confusion and naming clashes with other programming languages,
16997 it is desirable that the name of a package for a Java package is
16998 prefixed with @code{java-}. If a project already contains the word
16999 @code{java}, we drop this; for instance, the package @code{ngsjava} is
17000 packaged under the name @code{java-ngs}.
17002 For Java packages containing a single class or a small class hierarchy,
17003 we use the lowercase class name, replace all occurrences of @code{.} by
17004 dashes and prepend the prefix @code{java-}. So the class
17005 @code{apache.commons.cli} becomes package
17006 @code{java-apache-commons-cli}.
17013 For fonts that are in general not installed by a user for typesetting
17014 purposes, or that are distributed as part of a larger software package,
17015 we rely on the general packaging rules for software; for instance, this
17016 applies to the fonts delivered as part of the X.Org system or fonts that
17017 are part of TeX Live.
17019 To make it easier for a user to search for fonts, names for other packages
17020 containing only fonts are constructed as follows, independently of the
17021 upstream package name.
17023 The name of a package containing only one font family starts with
17024 @code{font-}; it is followed by the foundry name and a dash @code{-}
17025 if the foundry is known, and the font family name, in which spaces are
17026 replaced by dashes (and as usual, all upper case letters are transformed
17028 For example, the Gentium font family by SIL is packaged under the name
17029 @code{font-sil-gentium}.
17031 For a package containing several font families, the name of the collection
17032 is used in the place of the font family name.
17033 For instance, the Liberation fonts consist of three families,
17034 Liberation Sans, Liberation Serif and Liberation Mono.
17035 These could be packaged separately under the names
17036 @code{font-liberation-sans} and so on; but as they are distributed together
17037 under a common name, we prefer to package them together as
17038 @code{font-liberation}.
17040 In the case where several formats of the same font family or font collection
17041 are packaged separately, a short form of the format, prepended by a dash,
17042 is added to the package name. We use @code{-ttf} for TrueType fonts,
17043 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
17048 @node Bootstrapping
17049 @section Bootstrapping
17051 @c Adapted from the ELS 2013 paper.
17053 @cindex bootstrapping
17055 Bootstrapping in our context refers to how the distribution gets built
17056 ``from nothing''. Remember that the build environment of a derivation
17057 contains nothing but its declared inputs (@pxref{Introduction}). So
17058 there's an obvious chicken-and-egg problem: how does the first package
17059 get built? How does the first compiler get compiled? Note that this is
17060 a question of interest only to the curious hacker, not to the regular
17061 user, so you can shamelessly skip this section if you consider yourself
17062 a ``regular user''.
17064 @cindex bootstrap binaries
17065 The GNU system is primarily made of C code, with libc at its core. The
17066 GNU build system itself assumes the availability of a Bourne shell and
17067 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
17068 `grep'. Furthermore, build programs---programs that run
17069 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
17070 (@pxref{Derivations}). Consequently, to be able to build anything at
17071 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
17072 Binutils, libc, and the other packages mentioned above---the
17073 @dfn{bootstrap binaries}.
17075 These bootstrap binaries are ``taken for granted'', though we can also
17076 re-create them if needed (more on that later).
17078 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
17080 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
17081 @c large image, it's hard to scroll. Oh well.
17082 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17084 The figure above shows the very beginning of the dependency graph of the
17085 distribution, corresponding to the package definitions of the @code{(gnu
17086 packages bootstrap)} module. A similar figure can be generated with
17087 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17090 guix graph -t derivation \
17091 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17095 At this level of detail, things are
17096 slightly complex. First, Guile itself consists of an ELF executable,
17097 along with many source and compiled Scheme files that are dynamically
17098 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17099 tarball shown in this graph. This tarball is part of Guix's ``source''
17100 distribution, and gets inserted into the store with @code{add-to-store}
17101 (@pxref{The Store}).
17103 But how do we write a derivation that unpacks this tarball and adds it
17104 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17105 derivation---the first one that gets built---uses @code{bash} as its
17106 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17107 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17108 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17109 the Guix source distribution, whose sole purpose is to allow the Guile
17110 tarball to be unpacked.
17112 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17113 Guile that can be used to run subsequent build programs. Its first task
17114 is to download tarballs containing the other pre-built binaries---this
17115 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17116 @code{ftp-client.scm} are used for this purpose. The
17117 @code{module-import.drv} derivations import those modules in a directory
17118 in the store, using the original layout. The
17119 @code{module-import-compiled.drv} derivations compile those modules, and
17120 write them in an output directory with the right layout. This
17121 corresponds to the @code{#:modules} argument of
17122 @code{build-expression->derivation} (@pxref{Derivations}).
17124 Finally, the various tarballs are unpacked by the
17125 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17126 etc., at which point we have a working C tool chain.
17129 @unnumberedsubsec Building the Build Tools
17131 Bootstrapping is complete when we have a full tool chain that does not
17132 depend on the pre-built bootstrap tools discussed above. This
17133 no-dependency requirement is verified by checking whether the files of
17134 the final tool chain contain references to the @file{/gnu/store}
17135 directories of the bootstrap inputs. The process that leads to this
17136 ``final'' tool chain is described by the package definitions found in
17137 the @code{(gnu packages commencement)} module.
17139 The @command{guix graph} command allows us to ``zoom out'' compared to
17140 the graph above, by looking at the level of package objects instead of
17141 individual derivations---remember that a package may translate to
17142 several derivations, typically one derivation to download its source,
17143 one to build the Guile modules it needs, and one to actually build the
17144 package from source. The command:
17147 guix graph -t bag \
17148 -e '(@@@@ (gnu packages commencement)
17149 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17153 produces the dependency graph leading to the ``final'' C
17154 library@footnote{You may notice the @code{glibc-intermediate} label,
17155 suggesting that it is not @emph{quite} final, but as a good
17156 approximation, we will consider it final.}, depicted below.
17158 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17160 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17161 The first tool that gets built with the bootstrap binaries is
17162 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17163 for all the following packages. From there Findutils and Diffutils get
17166 Then come the first-stage Binutils and GCC, built as pseudo cross
17167 tools---i.e., with @code{--target} equal to @code{--host}. They are
17168 used to build libc. Thanks to this cross-build trick, this libc is
17169 guaranteed not to hold any reference to the initial tool chain.
17171 From there the final Binutils and GCC (not shown above) are built.
17173 from the final Binutils, and links programs against the just-built libc.
17174 This tool chain is used to build the other packages used by Guix and by
17175 the GNU Build System: Guile, Bash, Coreutils, etc.
17177 And voilà! At this point we have the complete set of build tools that
17178 the GNU Build System expects. These are in the @code{%final-inputs}
17179 variable of the @code{(gnu packages commencement)} module, and are
17180 implicitly used by any package that uses @code{gnu-build-system}
17181 (@pxref{Build Systems, @code{gnu-build-system}}).
17184 @unnumberedsubsec Building the Bootstrap Binaries
17186 @cindex bootstrap binaries
17187 Because the final tool chain does not depend on the bootstrap binaries,
17188 those rarely need to be updated. Nevertheless, it is useful to have an
17189 automated way to produce them, should an update occur, and this is what
17190 the @code{(gnu packages make-bootstrap)} module provides.
17192 The following command builds the tarballs containing the bootstrap
17193 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17194 of Coreutils and other basic command-line tools):
17197 guix build bootstrap-tarballs
17200 The generated tarballs are those that should be referred to in the
17201 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17204 Still here? Then perhaps by now you've started to wonder: when do we
17205 reach a fixed point? That is an interesting question! The answer is
17206 unknown, but if you would like to investigate further (and have
17207 significant computational and storage resources to do so), then let us
17211 @section Porting to a New Platform
17213 As discussed above, the GNU distribution is self-contained, and
17214 self-containment is achieved by relying on pre-built ``bootstrap
17215 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17216 operating system kernel, CPU architecture, and application binary
17217 interface (ABI). Thus, to port the distribution to a platform that is
17218 not yet supported, one must build those bootstrap binaries, and update
17219 the @code{(gnu packages bootstrap)} module to use them on that platform.
17221 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17222 When everything goes well, and assuming the GNU tool chain supports the
17223 target platform, this can be as simple as running a command like this
17227 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17230 For this to work, the @code{glibc-dynamic-linker} procedure in
17231 @code{(gnu packages bootstrap)} must be augmented to return the right
17232 file name for libc's dynamic linker on that platform; likewise,
17233 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17234 taught about the new platform.
17236 Once these are built, the @code{(gnu packages bootstrap)} module needs
17237 to be updated to refer to these binaries on the target platform. That
17238 is, the hashes and URLs of the bootstrap tarballs for the new platform
17239 must be added alongside those of the currently supported platforms. The
17240 bootstrap Guile tarball is treated specially: it is expected to be
17241 available locally, and @file{gnu/local.mk} has rules do download it for
17242 the supported architectures; a rule for the new platform must be added
17245 In practice, there may be some complications. First, it may be that the
17246 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17247 above) is not recognized by all the GNU tools. Typically, glibc
17248 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17249 configure flag (see @code{gcc.scm} for examples of how to handle this).
17250 Second, some of the required packages could fail to build for that
17251 platform. Lastly, the generated binaries could be broken for some
17254 @c *********************************************************************
17255 @include contributing.texi
17257 @c *********************************************************************
17258 @node Acknowledgments
17259 @chapter Acknowledgments
17261 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17262 which was designed and
17263 implemented by Eelco Dolstra, with contributions from other people (see
17264 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17265 management, and promoted unprecedented features, such as transactional
17266 package upgrades and rollbacks, per-user profiles, and referentially
17267 transparent build processes. Without this work, Guix would not exist.
17269 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17270 an inspiration for Guix.
17272 GNU@tie{}Guix itself is a collective work with contributions from a
17273 number of people. See the @file{AUTHORS} file in Guix for more
17274 information on these fine people. The @file{THANKS} file lists people
17275 who have helped by reporting bugs, taking care of the infrastructure,
17276 providing artwork and themes, making suggestions, and more---thank you!
17279 @c *********************************************************************
17280 @node GNU Free Documentation License
17281 @appendix GNU Free Documentation License
17282 @cindex license, GNU Free Documentation License
17283 @include fdl-1.3.texi
17285 @c *********************************************************************
17286 @node Concept Index
17287 @unnumbered Concept Index
17290 @node Programming Index
17291 @unnumbered Programming Index
17292 @syncodeindex tp fn
17293 @syncodeindex vr fn
17298 @c Local Variables:
17299 @c ispell-local-dictionary: "american";