6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
12 @c Identifier of the OpenPGP key used to sign tarballs and such.
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
40 Permission is granted to copy, distribute and/or modify this document
41 under the terms of the GNU Free Documentation License, Version 1.3 or
42 any later version published by the Free Software Foundation; with no
43 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
44 copy of the license is included in the section entitled ``GNU Free
45 Documentation License''.
48 @dircategory System administration
50 * Guix: (guix). Manage installed software and system configuration.
51 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
52 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
53 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
54 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
57 @dircategory Software development
59 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
60 * guix build: (guix)Invoking guix build. Building packages.
61 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
65 @title GNU Guix Reference Manual
66 @subtitle Using the GNU Guix Functional Package Manager
67 @author The GNU Guix Developers
70 @vskip 0pt plus 1filll
71 Edition @value{EDITION} @*
79 @c *********************************************************************
83 This document describes GNU Guix version @value{VERSION}, a functional
84 package management tool written for the GNU system.
87 * Introduction:: What is Guix about?
88 * Installation:: Installing Guix.
89 * Package Management:: Package installation, upgrade, etc.
90 * Programming Interface:: Using Guix in Scheme.
91 * Utilities:: Package management commands.
92 * GNU Distribution:: Software for your friendly GNU system.
93 * Contributing:: Your help needed!
95 * Acknowledgments:: Thanks!
96 * GNU Free Documentation License:: The license of this manual.
97 * Concept Index:: Concepts.
98 * Programming Index:: Data types, functions, and variables.
101 --- The Detailed Node Listing ---
105 * Binary Installation:: Getting Guix running in no time!
106 * Requirements:: Software needed to build and run Guix.
107 * Running the Test Suite:: Testing Guix.
108 * Setting Up the Daemon:: Preparing the build daemon's environment.
109 * Invoking guix-daemon:: Running the build daemon.
110 * Application Setup:: Application-specific setup.
112 Setting Up the Daemon
114 * Build Environment Setup:: Preparing the isolated build environment.
115 * Daemon Offload Setup:: Offloading builds to remote machines.
119 * Features:: How Guix will make your life brighter.
120 * Invoking guix package:: Package installation, removal, etc.
121 * Substitutes:: Downloading pre-built binaries.
122 * Packages with Multiple Outputs:: Single source package, multiple outputs.
123 * Invoking guix gc:: Running the garbage collector.
124 * Invoking guix pull:: Fetching the latest Guix and distribution.
125 * Invoking guix pack:: Creating software bundles.
126 * Invoking guix archive:: Exporting and importing store files.
128 Programming Interface
130 * Defining Packages:: Defining new packages.
131 * Build Systems:: Specifying how packages are built.
132 * The Store:: Manipulating the package store.
133 * Derivations:: Low-level interface to package derivations.
134 * The Store Monad:: Purely functional interface to the store.
135 * G-Expressions:: Manipulating build expressions.
139 * package Reference:: The package data type.
140 * origin Reference:: The origin data type.
144 * Invoking guix build:: Building packages from the command line.
145 * Invoking guix edit:: Editing package definitions.
146 * Invoking guix download:: Downloading a file and printing its hash.
147 * Invoking guix hash:: Computing the cryptographic hash of a file.
148 * Invoking guix import:: Importing package definitions.
149 * Invoking guix refresh:: Updating package definitions.
150 * Invoking guix lint:: Finding errors in package definitions.
151 * Invoking guix size:: Profiling disk usage.
152 * Invoking guix graph:: Visualizing the graph of packages.
153 * Invoking guix environment:: Setting up development environments.
154 * Invoking guix publish:: Sharing substitutes.
155 * Invoking guix challenge:: Challenging substitute servers.
156 * Invoking guix copy:: Copying to and from a remote store.
157 * Invoking guix container:: Process isolation.
159 Invoking @command{guix build}
161 * Common Build Options:: Build options for most commands.
162 * Package Transformation Options:: Creating variants of packages.
163 * Additional Build Options:: Options specific to 'guix build'.
167 * System Installation:: Installing the whole operating system.
168 * System Configuration:: Configuring the operating system.
169 * Documentation:: Browsing software user manuals.
170 * Installing Debugging Files:: Feeding the debugger.
171 * Security Updates:: Deploying security fixes quickly.
172 * Package Modules:: Packages from the programmer's viewpoint.
173 * Packaging Guidelines:: Growing the distribution.
174 * Bootstrapping:: GNU/Linux built from scratch.
175 * Porting:: Targeting another platform or kernel.
179 * Limitations:: What you can expect.
180 * Hardware Considerations:: Supported hardware.
181 * USB Stick Installation:: Preparing the installation medium.
182 * Preparing for Installation:: Networking, partitioning, etc.
183 * Proceeding with the Installation:: The real thing.
184 * Installing GuixSD in a VM:: GuixSD playground.
185 * Building the Installation Image:: How this comes to be.
189 * Using the Configuration System:: Customizing your GNU system.
190 * operating-system Reference:: Detail of operating-system declarations.
191 * File Systems:: Configuring file system mounts.
192 * Mapped Devices:: Block device extra processing.
193 * User Accounts:: Specifying user accounts.
194 * Locales:: Language and cultural convention settings.
195 * Services:: Specifying system services.
196 * Setuid Programs:: Programs running with root privileges.
197 * X.509 Certificates:: Authenticating HTTPS servers.
198 * Name Service Switch:: Configuring libc's name service switch.
199 * Initial RAM Disk:: Linux-Libre bootstrapping.
200 * GRUB Configuration:: Configuring the boot loader.
201 * Invoking guix system:: Instantiating a system configuration.
202 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
203 * Defining Services:: Adding new service definitions.
207 * Base Services:: Essential system services.
208 * Scheduled Job Execution:: The mcron service.
209 * Log Rotation:: The rottlog service.
210 * Networking Services:: Network setup, SSH daemon, etc.
211 * X Window:: Graphical display.
212 * Printing Services:: Local and remote printer support.
213 * Desktop Services:: D-Bus and desktop services.
214 * Database Services:: SQL databases.
215 * Mail Services:: IMAP, POP3, SMTP, and all that.
216 * Messaging Services:: Messaging services.
217 * Kerberos Services:: Kerberos services.
218 * Web Services:: Web servers.
219 * VPN Services:: VPN daemons.
220 * Network File System:: NFS related services.
221 * Continuous Integration:: The Cuirass service.
222 * Power management Services:: The TLP tool.
223 * Miscellaneous Services:: Other services.
227 * Service Composition:: The model for composing services.
228 * Service Types and Services:: Types and services.
229 * Service Reference:: API reference.
230 * Shepherd Services:: A particular type of service.
234 * Software Freedom:: What may go into the distribution.
235 * Package Naming:: What's in a name?
236 * Version Numbers:: When the name is not enough.
237 * Synopses and Descriptions:: Helping users find the right package.
238 * Python Modules:: A touch of British comedy.
239 * Perl Modules:: Little pearls.
240 * Java Packages:: Coffee break.
241 * Fonts:: Fond of fonts.
245 * Building from Git:: The latest and greatest.
246 * Running Guix Before It Is Installed:: Hacker tricks.
247 * The Perfect Setup:: The right tools.
248 * Coding Style:: Hygiene of the contributor.
249 * Submitting Patches:: Share your work.
253 * Programming Paradigm:: How to compose your elements.
254 * Modules:: Where to store your code?
255 * Data Types and Pattern Matching:: Implementing data structures.
256 * Formatting Code:: Writing conventions.
261 @c *********************************************************************
263 @chapter Introduction
266 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
267 using the international phonetic alphabet (IPA).} is a package
268 management tool for the GNU system. Guix makes it easy for unprivileged
269 users to install, upgrade, or remove packages, to roll back to a
270 previous package set, to build packages from source, and generally
271 assists with the creation and maintenance of software environments.
273 @cindex user interfaces
274 Guix provides a command-line package management interface
275 (@pxref{Invoking guix package}), a set of command-line utilities
276 (@pxref{Utilities}), as well as Scheme programming interfaces
277 (@pxref{Programming Interface}).
279 Its @dfn{build daemon} is responsible for building packages on behalf of
280 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
281 binaries from authorized sources (@pxref{Substitutes}).
283 @cindex extensibility of the distribution
284 @cindex customization, of packages
285 Guix includes package definitions for many GNU and non-GNU packages, all
286 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
287 user's computing freedom}. It is @emph{extensible}: users can write
288 their own package definitions (@pxref{Defining Packages}) and make them
289 available as independent package modules (@pxref{Package Modules}). It
290 is also @emph{customizable}: users can @emph{derive} specialized package
291 definitions from existing ones, including from the command line
292 (@pxref{Package Transformation Options}).
294 @cindex Guix System Distribution
296 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
297 where it complements the available tools without interference
298 (@pxref{Installation}), or you can use it as part of the standalone
299 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
300 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
301 system configuration and Guix takes care of instantiating the
302 configuration in a transactional, reproducible, and stateless fashion
303 (@pxref{System Configuration}).
305 @cindex functional package management
306 Under the hood, Guix implements the @dfn{functional package management}
307 discipline pioneered by Nix (@pxref{Acknowledgments}).
308 In Guix, the package build and installation process is seen
309 as a @emph{function}, in the mathematical sense. That function takes inputs,
310 such as build scripts, a compiler, and libraries, and
311 returns an installed package. As a pure function, its result depends
312 solely on its inputs---for instance, it cannot refer to software or
313 scripts that were not explicitly passed as inputs. A build function
314 always produces the same result when passed a given set of inputs. It
315 cannot alter the environment of the running system in
316 any way; for instance, it cannot create, modify, or delete files outside
317 of its build and installation directories. This is achieved by running
318 build processes in isolated environments (or @dfn{containers}), where only their
319 explicit inputs are visible.
322 The result of package build functions is @dfn{cached} in the file
323 system, in a special directory called @dfn{the store} (@pxref{The
324 Store}). Each package is installed in a directory of its own in the
325 store---by default under @file{/gnu/store}. The directory name contains
326 a hash of all the inputs used to build that package; thus, changing an
327 input yields a different directory name.
329 This approach is the foundation for the salient features of Guix: support
330 for transactional package upgrade and rollback, per-user installation, and
331 garbage collection of packages (@pxref{Features}).
334 @c *********************************************************************
336 @chapter Installation
338 @cindex installing Guix
339 GNU Guix is available for download from its website at
340 @url{http://www.gnu.org/software/guix/}. This section describes the
341 software requirements of Guix, as well as how to install it and get
344 Note that this section is concerned with the installation of the package
345 manager, which can be done on top of a running GNU/Linux system. If,
346 instead, you want to install the complete GNU operating system,
347 @pxref{System Installation}.
349 @cindex foreign distro
350 When installed on a running GNU/Linux system---thereafter called a
351 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
352 without interference. Its data lives exclusively in two directories,
353 usually @file{/gnu/store} and @file{/var/guix}; other files on your
354 system, such as @file{/etc}, are left untouched.
356 Once installed, Guix can be updated by running @command{guix pull}
357 (@pxref{Invoking guix pull}).
360 * Binary Installation:: Getting Guix running in no time!
361 * Requirements:: Software needed to build and run Guix.
362 * Running the Test Suite:: Testing Guix.
363 * Setting Up the Daemon:: Preparing the build daemon's environment.
364 * Invoking guix-daemon:: Running the build daemon.
365 * Application Setup:: Application-specific setup.
368 @node Binary Installation
369 @section Binary Installation
371 @cindex installing Guix from binaries
372 This section describes how to install Guix on an arbitrary system from a
373 self-contained tarball providing binaries for Guix and for all its
374 dependencies. This is often quicker than installing from source, which
375 is described in the next sections. The only requirement is to have
378 Installing goes along these lines:
382 @cindex downloading Guix binary
383 Download the binary tarball from
384 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
385 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
386 already running the kernel Linux, and so on.
388 @c The following is somewhat duplicated in ``System Installation''.
389 Make sure to download the associated @file{.sig} file and to verify the
390 authenticity of the tarball against it, along these lines:
393 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
394 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
397 If that command fails because you do not have the required public key,
398 then run this command to import it:
401 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
405 and rerun the @code{gpg --verify} command.
406 @c end authentication part
413 # tar --warning=no-timestamp -xf \
414 guix-binary-@value{VERSION}.@var{system}.tar.xz
415 # mv var/guix /var/ && mv gnu /
418 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
419 The latter contains a ready-to-use profile for @code{root} (see next
422 Do @emph{not} unpack the tarball on a working Guix system since that
423 would overwrite its own essential files.
425 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
426 not emit warnings about ``implausibly old time stamps'' (such
427 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
429 They stem from the fact that all the
430 files in the archive have their modification time set to zero (which
431 means January 1st, 1970.) This is done on purpose to make sure the
432 archive content is independent of its creation time, thus making it
436 Make @code{root}'s profile available under @file{~/.guix-profile}:
439 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
443 Source @file{etc/profile} to augment @code{PATH} and other relevant
444 environment variables:
447 # GUIX_PROFILE=$HOME/.guix-profile \
448 source $GUIX_PROFILE/etc/profile
452 Create the group and user accounts for build users as explained below
453 (@pxref{Build Environment Setup}).
456 Run the daemon, and set it to automatically start on boot.
458 If your host distro uses the systemd init system, this can be achieved
461 @c Versions of systemd that supported symlinked service files are not
462 @c yet widely deployed, so we should suggest that users copy the service
465 @c See this thread for more information:
466 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
469 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
471 # systemctl start guix-daemon && systemctl enable guix-daemon
474 If your host distro uses the Upstart init system:
477 # initctl reload-configuration
478 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
482 Otherwise, you can still start the daemon manually with:
485 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
489 Make the @command{guix} command available to other users on the machine,
493 # mkdir -p /usr/local/bin
495 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
498 It is also a good idea to make the Info version of this manual available
502 # mkdir -p /usr/local/share/info
503 # cd /usr/local/share/info
504 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
508 That way, assuming @file{/usr/local/share/info} is in the search path,
509 running @command{info guix} will open this manual (@pxref{Other Info
510 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
514 @cindex substitutes, authorization thereof
515 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
516 (@pxref{Substitutes}), authorize them:
519 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
523 Each user may need to perform a few additional steps to make their Guix
524 environment ready for use, @pxref{Application Setup}.
527 Voilà, the installation is complete!
529 You can confirm that Guix is working by installing a sample package into
533 # guix package -i hello
536 The @code{guix} package must remain available in @code{root}'s profile,
537 or it would become subject to garbage collection---in which case you
538 would find yourself badly handicapped by the lack of the @command{guix}
539 command. In other words, do not remove @code{guix} by running
540 @code{guix package -r guix}.
542 The binary installation tarball can be (re)produced and verified simply
543 by running the following command in the Guix source tree:
546 make guix-binary.@var{system}.tar.xz
550 ... which, in turn, runs:
553 guix pack -s @var{system} --localstatedir guix
556 @xref{Invoking guix pack}, for more info on this handy tool.
559 @section Requirements
561 This section lists requirements when building Guix from source. The
562 build procedure for Guix is the same as for other GNU software, and is
563 not covered here. Please see the files @file{README} and @file{INSTALL}
564 in the Guix source tree for additional details.
566 GNU Guix depends on the following packages:
569 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
570 later, including 2.2.x;
571 @item @url{http://gnupg.org/, GNU libgcrypt};
573 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
574 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
575 Guile,, gnutls-guile, GnuTLS-Guile});
576 @item @url{http://www.gnu.org/software/make/, GNU Make}.
579 The following dependencies are optional:
584 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
585 allow you to use the @command{guix import pypi} command (@pxref{Invoking
586 guix import}). It is of
587 interest primarily for developers and not for casual users.
590 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
591 Support for build offloading (@pxref{Daemon Offload Setup}) and
592 @command{guix copy} (@pxref{Invoking guix copy}) depends on
593 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
594 version 0.10.2 or later.
597 When @url{http://zlib.net, zlib} is available, @command{guix publish}
598 can compress build byproducts (@pxref{Invoking guix publish}).
601 Unless @code{--disable-daemon} was passed to @command{configure}, the
602 following packages are also needed:
605 @item @url{http://sqlite.org, SQLite 3};
606 @item @url{http://www.bzip.org, libbz2};
607 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
611 @cindex state directory
612 When configuring Guix on a system that already has a Guix installation,
613 be sure to specify the same state directory as the existing installation
614 using the @code{--localstatedir} option of the @command{configure}
615 script (@pxref{Directory Variables, @code{localstatedir},, standards,
616 GNU Coding Standards}). The @command{configure} script protects against
617 unintended misconfiguration of @var{localstatedir} so you do not
618 inadvertently corrupt your store (@pxref{The Store}).
620 @cindex Nix, compatibility
621 When a working installation of @url{http://nixos.org/nix/, the Nix package
622 manager} is available, you
623 can instead configure Guix with @code{--disable-daemon}. In that case,
624 Nix replaces the three dependencies above.
626 Guix is compatible with Nix, so it is possible to share the same store
627 between both. To do so, you must pass @command{configure} not only the
628 same @code{--with-store-dir} value, but also the same
629 @code{--localstatedir} value. The latter is essential because it
630 specifies where the database that stores metadata about the store is
631 located, among other things. The default values for Nix are
632 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
633 Note that @code{--disable-daemon} is not required if
634 your goal is to share the store with Nix.
636 @node Running the Test Suite
637 @section Running the Test Suite
640 After a successful @command{configure} and @code{make} run, it is a good
641 idea to run the test suite. It can help catch issues with the setup or
642 environment, or bugs in Guix itself---and really, reporting test
643 failures is a good way to help improve the software. To run the test
650 Test cases can run in parallel: you can use the @code{-j} option of
651 GNU@tie{}make to speed things up. The first run may take a few minutes
652 on a recent machine; subsequent runs will be faster because the store
653 that is created for test purposes will already have various things in
656 It is also possible to run a subset of the tests by defining the
657 @code{TESTS} makefile variable as in this example:
660 make check TESTS="tests/store.scm tests/cpio.scm"
663 By default, tests results are displayed at a file level. In order to
664 see the details of every individual test cases, it is possible to define
665 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
668 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
671 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
672 @file{test-suite.log} file. Please specify the Guix version being used
673 as well as version numbers of the dependencies (@pxref{Requirements}) in
676 Guix also comes with a whole-system test suite that tests complete
677 GuixSD operating system instances. It can only run on systems where
678 Guix is already installed, using:
685 or, again, by defining @code{TESTS} to select a subset of tests to run:
688 make check-system TESTS="basic mcron"
691 These system tests are defined in the @code{(gnu tests @dots{})}
692 modules. They work by running the operating systems under test with
693 lightweight instrumentation in a virtual machine (VM). They can be
694 computationally intensive or rather cheap, depending on whether
695 substitutes are available for their dependencies (@pxref{Substitutes}).
696 Some of them require a lot of storage space to hold VM images.
698 Again in case of test failures, please send @email{bug-guix@@gnu.org}
701 @node Setting Up the Daemon
702 @section Setting Up the Daemon
705 Operations such as building a package or running the garbage collector
706 are all performed by a specialized process, the @dfn{build daemon}, on
707 behalf of clients. Only the daemon may access the store and its
708 associated database. Thus, any operation that manipulates the store
709 goes through the daemon. For instance, command-line tools such as
710 @command{guix package} and @command{guix build} communicate with the
711 daemon (@i{via} remote procedure calls) to instruct it what to do.
713 The following sections explain how to prepare the build daemon's
714 environment. See also @ref{Substitutes}, for information on how to allow
715 the daemon to download pre-built binaries.
718 * Build Environment Setup:: Preparing the isolated build environment.
719 * Daemon Offload Setup:: Offloading builds to remote machines.
722 @node Build Environment Setup
723 @subsection Build Environment Setup
725 @cindex build environment
726 In a standard multi-user setup, Guix and its daemon---the
727 @command{guix-daemon} program---are installed by the system
728 administrator; @file{/gnu/store} is owned by @code{root} and
729 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
730 Guix tools to build packages or otherwise access the store, and the
731 daemon will do it on their behalf, ensuring that the store is kept in a
732 consistent state, and allowing built packages to be shared among users.
735 When @command{guix-daemon} runs as @code{root}, you may not want package
736 build processes themselves to run as @code{root} too, for obvious
737 security reasons. To avoid that, a special pool of @dfn{build users}
738 should be created for use by build processes started by the daemon.
739 These build users need not have a shell and a home directory: they will
740 just be used when the daemon drops @code{root} privileges in build
741 processes. Having several such users allows the daemon to launch
742 distinct build processes under separate UIDs, which guarantees that they
743 do not interfere with each other---an essential feature since builds are
744 regarded as pure functions (@pxref{Introduction}).
746 On a GNU/Linux system, a build user pool may be created like this (using
747 Bash syntax and the @code{shadow} commands):
749 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
750 @c for why `-G' is needed.
752 # groupadd --system guixbuild
753 # for i in `seq -w 1 10`;
755 useradd -g guixbuild -G guixbuild \
756 -d /var/empty -s `which nologin` \
757 -c "Guix build user $i" --system \
763 The number of build users determines how many build jobs may run in
764 parallel, as specified by the @option{--max-jobs} option
765 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
766 @command{guix system vm} and related commands, you may need to add the
767 build users to the @code{kvm} group so they can access @file{/dev/kvm},
768 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
769 (@pxref{Invoking guix system}).
771 The @code{guix-daemon} program may then be run as @code{root} with the
772 following command@footnote{If your machine uses the systemd init system,
773 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
774 file in @file{/etc/systemd/system} will ensure that
775 @command{guix-daemon} is automatically started. Similarly, if your
776 machine uses the Upstart init system, drop the
777 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
778 file in @file{/etc/init}.}:
781 # guix-daemon --build-users-group=guixbuild
786 This way, the daemon starts build processes in a chroot, under one of
787 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
788 environment contains nothing but:
790 @c Keep this list in sync with libstore/build.cc! -----------------------
793 a minimal @code{/dev} directory, created mostly independently from the
794 host @code{/dev}@footnote{``Mostly'', because while the set of files
795 that appear in the chroot's @code{/dev} is fixed, most of these files
796 can only be created if the host has them.};
799 the @code{/proc} directory; it only shows the processes of the container
800 since a separate PID name space is used;
803 @file{/etc/passwd} with an entry for the current user and an entry for
807 @file{/etc/group} with an entry for the user's group;
810 @file{/etc/hosts} with an entry that maps @code{localhost} to
814 a writable @file{/tmp} directory.
817 You can influence the directory where the daemon stores build trees
818 @i{via} the @code{TMPDIR} environment variable. However, the build tree
819 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
820 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
821 This way, the value of @code{TMPDIR} does not leak inside build
822 environments, which avoids discrepancies in cases where build processes
823 capture the name of their build tree.
826 The daemon also honors the @code{http_proxy} environment variable for
827 HTTP downloads it performs, be it for fixed-output derivations
828 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
830 If you are installing Guix as an unprivileged user, it is still possible
831 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
832 However, build processes will not be isolated from one another, and not
833 from the rest of the system. Thus, build processes may interfere with
834 each other, and may access programs, libraries, and other files
835 available on the system---making it much harder to view them as
836 @emph{pure} functions.
839 @node Daemon Offload Setup
840 @subsection Using the Offload Facility
844 When desired, the build daemon can @dfn{offload} derivation builds to
845 other machines running Guix, using the @code{offload} @dfn{build
846 hook}@footnote{This feature is available only when
847 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
849 feature is enabled, a list of user-specified build machines is read from
850 @file{/etc/guix/machines.scm}; every time a build is requested, for
851 instance via @code{guix build}, the daemon attempts to offload it to one
852 of the machines that satisfy the constraints of the derivation, in
853 particular its system type---e.g., @file{x86_64-linux}. Missing
854 prerequisites for the build are copied over SSH to the target machine,
855 which then proceeds with the build; upon success the output(s) of the
856 build are copied back to the initial machine.
858 The @file{/etc/guix/machines.scm} file typically looks like this:
862 (name "eightysix.example.org")
863 (system "x86_64-linux")
864 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
866 (speed 2.)) ;incredibly fast!
869 (name "meeps.example.org")
870 (system "mips64el-linux")
871 (host-key "ssh-rsa AAAAB3Nza@dots{}")
874 (string-append (getenv "HOME")
875 "/.ssh/identity-for-guix"))))
879 In the example above we specify a list of two build machines, one for
880 the @code{x86_64} architecture and one for the @code{mips64el}
883 In fact, this file is---not surprisingly!---a Scheme file that is
884 evaluated when the @code{offload} hook is started. Its return value
885 must be a list of @code{build-machine} objects. While this example
886 shows a fixed list of build machines, one could imagine, say, using
887 DNS-SD to return a list of potential build machines discovered in the
888 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
889 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
892 @deftp {Data Type} build-machine
893 This data type represents build machines to which the daemon may offload
894 builds. The important fields are:
899 The host name of the remote machine.
902 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
905 The user account to use when connecting to the remote machine over SSH.
906 Note that the SSH key pair must @emph{not} be passphrase-protected, to
907 allow non-interactive logins.
910 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
911 This is used to authenticate the machine when we connect to it. It is a
912 long string that looks like this:
915 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
918 If the machine is running the OpenSSH daemon, @command{sshd}, the host
919 key can be found in a file such as
920 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
922 If the machine is running the SSH daemon of GNU@tie{}lsh,
923 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
924 similar file. It can be converted to the OpenSSH format using
925 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
928 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
929 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
934 A number of optional fields may be specified:
938 @item @code{port} (default: @code{22})
939 Port number of SSH server on the machine.
941 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
942 The SSH private key file to use when connecting to the machine, in
945 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
946 @itemx @code{compression-level} (default: @code{3})
947 The SSH-level compression methods and compression level requested.
949 Note that offloading relies on SSH compression to reduce bandwidth usage
950 when transferring files to and from build machines.
952 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
953 File name of the Unix-domain socket @command{guix-daemon} is listening
956 @item @code{parallel-builds} (default: @code{1})
957 The number of builds that may run in parallel on the machine.
959 @item @code{speed} (default: @code{1.0})
960 A ``relative speed factor''. The offload scheduler will tend to prefer
961 machines with a higher speed factor.
963 @item @code{features} (default: @code{'()})
964 A list of strings denoting specific features supported by the machine.
965 An example is @code{"kvm"} for machines that have the KVM Linux modules
966 and corresponding hardware support. Derivations can request features by
967 name, and they will be scheduled on matching build machines.
972 The @code{guile} command must be in the search path on the build
973 machines. In addition, the Guix modules must be in
974 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
975 this is the case by running:
978 ssh build-machine guile -c "'(use-modules (guix config))'"
981 There is one last thing to do once @file{machines.scm} is in place. As
982 explained above, when offloading, files are transferred back and forth
983 between the machine stores. For this to work, you first need to
984 generate a key pair on each machine to allow the daemon to export signed
985 archives of files from the store (@pxref{Invoking guix archive}):
988 # guix archive --generate-key
992 Each build machine must authorize the key of the master machine so that
993 it accepts store items it receives from the master:
996 # guix archive --authorize < master-public-key.txt
1000 Likewise, the master machine must authorize the key of each build machine.
1002 All the fuss with keys is here to express pairwise mutual trust
1003 relations between the master and the build machines. Concretely, when
1004 the master receives files from a build machine (and @i{vice versa}), its
1005 build daemon can make sure they are genuine, have not been tampered
1006 with, and that they are signed by an authorized key.
1008 @cindex offload test
1009 To test whether your setup is operational, run this command on the
1016 This will attempt to connect to each of the build machines specified in
1017 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1018 available on each machine, attempt to export to the machine and import
1019 from it, and report any error in the process.
1021 If you want to test a different machine file, just specify it on the
1025 # guix offload test machines-qualif.scm
1028 Last, you can test the subset of the machines whose name matches a
1029 regular expression like this:
1032 # guix offload test machines.scm '\.gnu\.org$'
1035 @node Invoking guix-daemon
1036 @section Invoking @command{guix-daemon}
1038 The @command{guix-daemon} program implements all the functionality to
1039 access the store. This includes launching build processes, running the
1040 garbage collector, querying the availability of a build result, etc. It
1041 is normally run as @code{root} like this:
1044 # guix-daemon --build-users-group=guixbuild
1048 For details on how to set it up, @pxref{Setting Up the Daemon}.
1051 @cindex container, build environment
1052 @cindex build environment
1053 @cindex reproducible builds
1054 By default, @command{guix-daemon} launches build processes under
1055 different UIDs, taken from the build group specified with
1056 @code{--build-users-group}. In addition, each build process is run in a
1057 chroot environment that only contains the subset of the store that the
1058 build process depends on, as specified by its derivation
1059 (@pxref{Programming Interface, derivation}), plus a set of specific
1060 system directories. By default, the latter contains @file{/dev} and
1061 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1062 @dfn{container}: in addition to having its own file system tree, it has
1063 a separate mount name space, its own PID name space, network name space,
1064 etc. This helps achieve reproducible builds (@pxref{Features}).
1066 When the daemon performs a build on behalf of the user, it creates a
1067 build directory under @file{/tmp} or under the directory specified by
1068 its @code{TMPDIR} environment variable; this directory is shared with
1069 the container for the duration of the build. Be aware that using a
1070 directory other than @file{/tmp} can affect build results---for example,
1071 with a longer directory name, a build process that uses Unix-domain
1072 sockets might hit the name length limitation for @code{sun_path}, which
1073 it would otherwise not hit.
1075 The build directory is automatically deleted upon completion, unless the
1076 build failed and the client specified @option{--keep-failed}
1077 (@pxref{Invoking guix build, @option{--keep-failed}}).
1079 The following command-line options are supported:
1082 @item --build-users-group=@var{group}
1083 Take users from @var{group} to run build processes (@pxref{Setting Up
1084 the Daemon, build users}).
1086 @item --no-substitutes
1088 Do not use substitutes for build products. That is, always build things
1089 locally instead of allowing downloads of pre-built binaries
1090 (@pxref{Substitutes}).
1092 By default substitutes are used, unless the client---such as the
1093 @command{guix package} command---is explicitly invoked with
1094 @code{--no-substitutes}.
1096 When the daemon runs with @code{--no-substitutes}, clients can still
1097 explicitly enable substitution @i{via} the @code{set-build-options}
1098 remote procedure call (@pxref{The Store}).
1100 @item --substitute-urls=@var{urls}
1101 @anchor{daemon-substitute-urls}
1102 Consider @var{urls} the default whitespace-separated list of substitute
1103 source URLs. When this option is omitted,
1104 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1105 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1107 This means that substitutes may be downloaded from @var{urls}, as long
1108 as they are signed by a trusted signature (@pxref{Substitutes}).
1111 @item --no-build-hook
1112 Do not use the @dfn{build hook}.
1114 The build hook is a helper program that the daemon can start and to
1115 which it submits build requests. This mechanism is used to offload
1116 builds to other machines (@pxref{Daemon Offload Setup}).
1118 @item --cache-failures
1119 Cache build failures. By default, only successful builds are cached.
1121 When this option is used, @command{guix gc --list-failures} can be used
1122 to query the set of store items marked as failed; @command{guix gc
1123 --clear-failures} removes store items from the set of cached failures.
1124 @xref{Invoking guix gc}.
1126 @item --cores=@var{n}
1128 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1131 The default value is @code{0}, but it may be overridden by clients, such
1132 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1135 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1136 in the build process, which can then use it to exploit internal
1137 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1139 @item --max-jobs=@var{n}
1141 Allow at most @var{n} build jobs in parallel. The default value is
1142 @code{1}. Setting it to @code{0} means that no builds will be performed
1143 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1144 Setup}), or simply fail.
1146 @item --rounds=@var{N}
1147 Build each derivation @var{n} times in a row, and raise an error if
1148 consecutive build results are not bit-for-bit identical. Note that this
1149 setting can be overridden by clients such as @command{guix build}
1150 (@pxref{Invoking guix build}).
1152 When used in conjunction with @option{--keep-failed}, the differing
1153 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1154 This makes it easy to look for differences between the two results.
1157 Produce debugging output.
1159 This is useful to debug daemon start-up issues, but then it may be
1160 overridden by clients, for example the @code{--verbosity} option of
1161 @command{guix build} (@pxref{Invoking guix build}).
1163 @item --chroot-directory=@var{dir}
1164 Add @var{dir} to the build chroot.
1166 Doing this may change the result of build processes---for instance if
1167 they use optional dependencies found in @var{dir} when it is available,
1168 and not otherwise. For that reason, it is not recommended to do so.
1169 Instead, make sure that each derivation declares all the inputs that it
1172 @item --disable-chroot
1173 Disable chroot builds.
1175 Using this option is not recommended since, again, it would allow build
1176 processes to gain access to undeclared dependencies. It is necessary,
1177 though, when @command{guix-daemon} is running under an unprivileged user
1180 @item --disable-log-compression
1181 Disable compression of the build logs.
1183 Unless @code{--lose-logs} is used, all the build logs are kept in the
1184 @var{localstatedir}. To save space, the daemon automatically compresses
1185 them with bzip2 by default. This option disables that.
1187 @item --disable-deduplication
1188 @cindex deduplication
1189 Disable automatic file ``deduplication'' in the store.
1191 By default, files added to the store are automatically ``deduplicated'':
1192 if a newly added file is identical to another one found in the store,
1193 the daemon makes the new file a hard link to the other file. This can
1194 noticeably reduce disk usage, at the expense of slightly increased
1195 input/output load at the end of a build process. This option disables
1198 @item --gc-keep-outputs[=yes|no]
1199 Tell whether the garbage collector (GC) must keep outputs of live
1202 When set to ``yes'', the GC will keep the outputs of any live derivation
1203 available in the store---the @code{.drv} files. The default is ``no'',
1204 meaning that derivation outputs are kept only if they are GC roots.
1206 @item --gc-keep-derivations[=yes|no]
1207 Tell whether the garbage collector (GC) must keep derivations
1208 corresponding to live outputs.
1210 When set to ``yes'', as is the case by default, the GC keeps
1211 derivations---i.e., @code{.drv} files---as long as at least one of their
1212 outputs is live. This allows users to keep track of the origins of
1213 items in their store. Setting it to ``no'' saves a bit of disk space.
1215 Note that when both @code{--gc-keep-derivations} and
1216 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1217 prerequisites (the sources, compiler, libraries, and other build-time
1218 tools) of live objects in the store, regardless of whether these
1219 prerequisites are live. This is convenient for developers since it
1220 saves rebuilds or downloads.
1222 @item --impersonate-linux-2.6
1223 On Linux-based systems, impersonate Linux 2.6. This means that the
1224 kernel's @code{uname} system call will report 2.6 as the release number.
1226 This might be helpful to build programs that (usually wrongfully) depend
1227 on the kernel version number.
1230 Do not keep build logs. By default they are kept under
1231 @code{@var{localstatedir}/guix/log}.
1233 @item --system=@var{system}
1234 Assume @var{system} as the current system type. By default it is the
1235 architecture/kernel pair found at configure time, such as
1236 @code{x86_64-linux}.
1238 @item --listen=@var{socket}
1239 Listen for connections on @var{socket}, the file name of a Unix-domain
1240 socket. The default socket is
1241 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1242 useful in exceptional circumstances, such as if you need to run several
1243 daemons on the same machine.
1247 @node Application Setup
1248 @section Application Setup
1250 @cindex foreign distro
1251 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1252 so-called @dfn{foreign distro}---a few additional steps are needed to
1253 get everything in place. Here are some of them.
1257 @anchor{locales-and-locpath}
1258 @cindex locales, when not on GuixSD
1260 @vindex GUIX_LOCPATH
1261 Packages installed @i{via} Guix will not use the locale data of the
1262 host system. Instead, you must first install one of the locale packages
1263 available with Guix and then define the @code{GUIX_LOCPATH} environment
1267 $ guix package -i glibc-locales
1268 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1271 Note that the @code{glibc-locales} package contains data for all the
1272 locales supported by the GNU@tie{}libc and weighs in at around
1273 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1274 limited to a few UTF-8 locales.
1276 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1277 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1278 Manual}). There are two important differences though:
1282 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1283 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1284 to make sure the programs of the foreign distro will not end up loading
1285 incompatible locale data.
1288 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1289 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1290 should your Guix profile contain a mixture of programs linked against
1291 different libc version, each libc version will only try to load locale
1292 data in the right format.
1295 This is important because the locale data format used by different libc
1296 versions may be incompatible.
1298 @subsection Name Service Switch
1300 @cindex name service switch, glibc
1301 @cindex NSS (name service switch), glibc
1302 @cindex nscd (name service caching daemon)
1303 @cindex name service caching daemon (nscd)
1304 When using Guix on a foreign distro, we @emph{strongly recommend} that
1305 the system run the GNU C library's @dfn{name service cache daemon},
1306 @command{nscd}, which should be listening on the
1307 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1308 installed with Guix may fail to look up host names or user accounts, or
1309 may even crash. The next paragraphs explain why.
1311 @cindex @file{nsswitch.conf}
1312 The GNU C library implements a @dfn{name service switch} (NSS), which is
1313 an extensible mechanism for ``name lookups'' in general: host name
1314 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1315 The GNU C Library Reference Manual}).
1317 @cindex Network information service (NIS)
1318 @cindex NIS (Network information service)
1319 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1320 lookup implementations: for example, the @code{nss-mdns} plugin allow
1321 resolution of @code{.local} host names, the @code{nis} plugin allows
1322 user account lookup using the Network information service (NIS), and so
1323 on. These extra ``lookup services'' are configured system-wide in
1324 @file{/etc/nsswitch.conf}, and all the programs running on the system
1325 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1328 When they perform a name lookup---for instance by calling the
1329 @code{getaddrinfo} function in C---applications first try to connect to
1330 the nscd; on success, nscd performs name lookups on their behalf. If
1331 the nscd is not running, then they perform the name lookup by
1332 themselves, by loading the name lookup services into their own address
1333 space and running it. These name lookup services---the
1334 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1335 the host system's C library, rather than from the C library the
1336 application is linked against (the C library coming from Guix).
1338 And this is where the problem is: if your application is linked against
1339 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1340 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1341 likely crash or have its name lookups fail unexpectedly.
1343 Running @command{nscd} on the system, among other advantages, eliminates
1344 this binary incompatibility problem because those @code{libnss_*.so}
1345 files are loaded in the @command{nscd} process, not in applications
1348 @subsection X11 Fonts
1351 The majority of graphical applications use Fontconfig to locate and
1352 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1353 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1354 by default. Thus, to allow graphical applications installed with Guix
1355 to display fonts, you have to install fonts with Guix as well.
1356 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1357 @code{font-gnu-freefont-ttf}.
1359 To display text written in Chinese languages, Japanese, or Korean in
1360 graphical applications, consider installing
1361 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1362 has multiple outputs, one per language family (@pxref{Packages with
1363 Multiple Outputs}). For instance, the following command installs fonts
1364 for Chinese languages:
1367 guix package -i font-adobe-source-han-sans:cn
1370 @cindex @code{xterm}
1371 Older programs such as @command{xterm} do not use Fontconfig and instead
1372 rely on server-side font rendering. Such programs require to specify a
1373 full name of a font using XLFD (X Logical Font Description), like this:
1376 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1379 To be able to use such full names for the TrueType fonts installed in
1380 your Guix profile, you need to extend the font path of the X server:
1383 xset +fp ~/.guix-profile/share/fonts/truetype
1386 @cindex @code{xlsfonts}
1387 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1388 to make sure your TrueType fonts are listed there.
1390 @subsection X.509 Certificates
1392 @cindex @code{nss-certs}
1393 The @code{nss-certs} package provides X.509 certificates, which allow
1394 programs to authenticate Web servers accessed over HTTPS.
1396 When using Guix on a foreign distro, you can install this package and
1397 define the relevant environment variables so that packages know where to
1398 look for certificates. @xref{X.509 Certificates}, for detailed
1401 @subsection Emacs Packages
1403 @cindex @code{emacs}
1404 When you install Emacs packages with Guix, the elisp files may be placed
1405 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1407 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1408 directory exists because potentially there may exist thousands of Emacs
1409 packages and storing all their files in a single directory may be not
1410 reliable (because of name conflicts). So we think using a separate
1411 directory for each package is a good idea. It is very similar to how
1412 the Emacs package system organizes the file structure (@pxref{Package
1413 Files,,, emacs, The GNU Emacs Manual}).
1415 By default, Emacs (installed with Guix) ``knows'' where these packages
1416 are placed, so you do not need to perform any configuration. If, for
1417 some reason, you want to avoid auto-loading Emacs packages installed
1418 with Guix, you can do so by running Emacs with @code{--no-site-file}
1419 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1423 @c *********************************************************************
1424 @node Package Management
1425 @chapter Package Management
1428 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1429 remove software packages, without having to know about their build
1430 procedures or dependencies. Guix also goes beyond this obvious set of
1433 This chapter describes the main features of Guix, as well as the package
1434 management tools it provides. Along with the command-line interface
1435 described below (@pxref{Invoking guix package, @code{guix package}}),
1436 you may also use Emacs Interface, after installing @code{emacs-guix}
1437 package (run @kbd{M-x guix-help} command to start with it):
1440 guix package -i emacs-guix
1444 * Features:: How Guix will make your life brighter.
1445 * Invoking guix package:: Package installation, removal, etc.
1446 * Substitutes:: Downloading pre-built binaries.
1447 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1448 * Invoking guix gc:: Running the garbage collector.
1449 * Invoking guix pull:: Fetching the latest Guix and distribution.
1450 * Invoking guix pack:: Creating software bundles.
1451 * Invoking guix archive:: Exporting and importing store files.
1457 When using Guix, each package ends up in the @dfn{package store}, in its
1458 own directory---something that resembles
1459 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1461 Instead of referring to these directories, users have their own
1462 @dfn{profile}, which points to the packages that they actually want to
1463 use. These profiles are stored within each user's home directory, at
1464 @code{$HOME/.guix-profile}.
1466 For example, @code{alice} installs GCC 4.7.2. As a result,
1467 @file{/home/alice/.guix-profile/bin/gcc} points to
1468 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1469 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1470 simply continues to point to
1471 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1472 coexist on the same system without any interference.
1474 The @command{guix package} command is the central tool to manage
1475 packages (@pxref{Invoking guix package}). It operates on the per-user
1476 profiles, and can be used @emph{with normal user privileges}.
1478 @cindex transactions
1479 The command provides the obvious install, remove, and upgrade
1480 operations. Each invocation is actually a @emph{transaction}: either
1481 the specified operation succeeds, or nothing happens. Thus, if the
1482 @command{guix package} process is terminated during the transaction,
1483 or if a power outage occurs during the transaction, then the user's
1484 profile remains in its previous state, and remains usable.
1486 In addition, any package transaction may be @emph{rolled back}. So, if,
1487 for example, an upgrade installs a new version of a package that turns
1488 out to have a serious bug, users may roll back to the previous instance
1489 of their profile, which was known to work well. Similarly, the global
1490 system configuration on GuixSD is subject to
1491 transactional upgrades and roll-back
1492 (@pxref{Using the Configuration System}).
1494 All packages in the package store may be @emph{garbage-collected}.
1495 Guix can determine which packages are still referenced by user
1496 profiles, and remove those that are provably no longer referenced
1497 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1498 generations of their profile so that the packages they refer to can be
1501 @cindex reproducibility
1502 @cindex reproducible builds
1503 Finally, Guix takes a @dfn{purely functional} approach to package
1504 management, as described in the introduction (@pxref{Introduction}).
1505 Each @file{/gnu/store} package directory name contains a hash of all the
1506 inputs that were used to build that package---compiler, libraries, build
1507 scripts, etc. This direct correspondence allows users to make sure a
1508 given package installation matches the current state of their
1509 distribution. It also helps maximize @dfn{build reproducibility}:
1510 thanks to the isolated build environments that are used, a given build
1511 is likely to yield bit-identical files when performed on different
1512 machines (@pxref{Invoking guix-daemon, container}).
1515 This foundation allows Guix to support @dfn{transparent binary/source
1516 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1517 available from an external source---a @dfn{substitute}, Guix just
1518 downloads it and unpacks it;
1519 otherwise, it builds the package from source, locally
1520 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1521 reproducible, users do not have to trust servers that provide
1522 substitutes: they can force a local build and @emph{challenge} providers
1523 (@pxref{Invoking guix challenge}).
1525 Control over the build environment is a feature that is also useful for
1526 developers. The @command{guix environment} command allows developers of
1527 a package to quickly set up the right development environment for their
1528 package, without having to manually install the dependencies of the
1529 package into their profile (@pxref{Invoking guix environment}).
1531 @node Invoking guix package
1532 @section Invoking @command{guix package}
1534 @cindex installing packages
1535 @cindex removing packages
1536 @cindex package installation
1537 @cindex package removal
1538 The @command{guix package} command is the tool that allows users to
1539 install, upgrade, and remove packages, as well as rolling back to
1540 previous configurations. It operates only on the user's own profile,
1541 and works with normal user privileges (@pxref{Features}). Its syntax
1545 guix package @var{options}
1547 @cindex transactions
1548 Primarily, @var{options} specifies the operations to be performed during
1549 the transaction. Upon completion, a new profile is created, but
1550 previous @dfn{generations} of the profile remain available, should the user
1553 For example, to remove @code{lua} and install @code{guile} and
1554 @code{guile-cairo} in a single transaction:
1557 guix package -r lua -i guile guile-cairo
1560 @command{guix package} also supports a @dfn{declarative approach}
1561 whereby the user specifies the exact set of packages to be available and
1562 passes it @i{via} the @option{--manifest} option
1563 (@pxref{profile-manifest, @option{--manifest}}).
1566 For each user, a symlink to the user's default profile is automatically
1567 created in @file{$HOME/.guix-profile}. This symlink always points to the
1568 current generation of the user's default profile. Thus, users can add
1569 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1570 variable, and so on.
1571 @cindex search paths
1572 If you are not using the Guix System Distribution, consider adding the
1573 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1574 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1575 shells get all the right environment variable definitions:
1578 GUIX_PROFILE="$HOME/.guix-profile" \
1579 source "$HOME/.guix-profile/etc/profile"
1582 In a multi-user setup, user profiles are stored in a place registered as
1583 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1584 to (@pxref{Invoking guix gc}). That directory is normally
1585 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1586 @var{localstatedir} is the value passed to @code{configure} as
1587 @code{--localstatedir}, and @var{user} is the user name. The
1588 @file{per-user} directory is created when @command{guix-daemon} is
1589 started, and the @var{user} sub-directory is created by @command{guix
1592 The @var{options} can be among the following:
1596 @item --install=@var{package} @dots{}
1597 @itemx -i @var{package} @dots{}
1598 Install the specified @var{package}s.
1600 Each @var{package} may specify either a simple package name, such as
1601 @code{guile}, or a package name followed by an at-sign and version number,
1602 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1603 case, the newest version prefixed by @code{1.8} is selected.)
1605 If no version number is specified, the
1606 newest available version will be selected. In addition, @var{package}
1607 may contain a colon, followed by the name of one of the outputs of the
1608 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1609 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1610 name (and optionally version) are searched for among the GNU
1611 distribution modules (@pxref{Package Modules}).
1613 @cindex propagated inputs
1614 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1615 that automatically get installed along with the required package
1616 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1617 @code{package} objects}, for information about propagated inputs in
1618 package definitions).
1620 @anchor{package-cmd-propagated-inputs}
1621 An example is the GNU MPC library: its C header files refer to those of
1622 the GNU MPFR library, which in turn refer to those of the GMP library.
1623 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1624 in the profile; removing MPC also removes MPFR and GMP---unless they had
1625 also been explicitly installed by the user.
1627 Besides, packages sometimes rely on the definition of environment
1628 variables for their search paths (see explanation of
1629 @code{--search-paths} below). Any missing or possibly incorrect
1630 environment variable definitions are reported here.
1632 @item --install-from-expression=@var{exp}
1634 Install the package @var{exp} evaluates to.
1636 @var{exp} must be a Scheme expression that evaluates to a
1637 @code{<package>} object. This option is notably useful to disambiguate
1638 between same-named variants of a package, with expressions such as
1639 @code{(@@ (gnu packages base) guile-final)}.
1641 Note that this option installs the first output of the specified
1642 package, which may be insufficient when needing a specific output of a
1643 multiple-output package.
1645 @item --install-from-file=@var{file}
1646 @itemx -f @var{file}
1647 Install the package that the code within @var{file} evaluates to.
1649 As an example, @var{file} might contain a definition like this
1650 (@pxref{Defining Packages}):
1653 @verbatiminclude package-hello.scm
1656 Developers may find it useful to include such a @file{guix.scm} file
1657 in the root of their project source tree that can be used to test
1658 development snapshots and create reproducible development environments
1659 (@pxref{Invoking guix environment}).
1661 @item --remove=@var{package} @dots{}
1662 @itemx -r @var{package} @dots{}
1663 Remove the specified @var{package}s.
1665 As for @code{--install}, each @var{package} may specify a version number
1666 and/or output name in addition to the package name. For instance,
1667 @code{-r glibc:debug} would remove the @code{debug} output of
1670 @item --upgrade[=@var{regexp} @dots{}]
1671 @itemx -u [@var{regexp} @dots{}]
1672 @cindex upgrading packages
1673 Upgrade all the installed packages. If one or more @var{regexp}s are
1674 specified, upgrade only installed packages whose name matches a
1675 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1677 Note that this upgrades package to the latest version of packages found
1678 in the distribution currently installed. To update your distribution,
1679 you should regularly run @command{guix pull} (@pxref{Invoking guix
1682 @item --do-not-upgrade[=@var{regexp} @dots{}]
1683 When used together with the @code{--upgrade} option, do @emph{not}
1684 upgrade any packages whose name matches a @var{regexp}. For example, to
1685 upgrade all packages in the current profile except those containing the
1686 substring ``emacs'':
1689 $ guix package --upgrade . --do-not-upgrade emacs
1692 @item @anchor{profile-manifest}--manifest=@var{file}
1693 @itemx -m @var{file}
1694 @cindex profile declaration
1695 @cindex profile manifest
1696 Create a new generation of the profile from the manifest object
1697 returned by the Scheme code in @var{file}.
1699 This allows you to @emph{declare} the profile's contents rather than
1700 constructing it through a sequence of @code{--install} and similar
1701 commands. The advantage is that @var{file} can be put under version
1702 control, copied to different machines to reproduce the same profile, and
1705 @c FIXME: Add reference to (guix profile) documentation when available.
1706 @var{file} must return a @dfn{manifest} object, which is roughly a list
1709 @findex packages->manifest
1711 (use-package-modules guile emacs)
1716 ;; Use a specific package output.
1717 (list guile-2.0 "debug")))
1720 @findex specification->package+output
1721 In this example we have to know which modules define the @code{emacs}
1722 and @code{guile-2.0} variables to provide the right
1723 @code{use-package-modules} line, which can be cumbersome. We can
1724 instead provide regular package specifications and let
1725 @code{specification->package-output} look up the corresponding package
1730 (map (compose list specification->package+output)
1731 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1735 @cindex rolling back
1736 @cindex undoing transactions
1737 @cindex transactions, undoing
1738 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1739 the last transaction.
1741 When combined with options such as @code{--install}, roll back occurs
1742 before any other actions.
1744 When rolling back from the first generation that actually contains
1745 installed packages, the profile is made to point to the @dfn{zeroth
1746 generation}, which contains no files apart from its own metadata.
1748 After having rolled back, installing, removing, or upgrading packages
1749 overwrites previous future generations. Thus, the history of the
1750 generations in a profile is always linear.
1752 @item --switch-generation=@var{pattern}
1753 @itemx -S @var{pattern}
1755 Switch to a particular generation defined by @var{pattern}.
1757 @var{pattern} may be either a generation number or a number prefixed
1758 with ``+'' or ``-''. The latter means: move forward/backward by a
1759 specified number of generations. For example, if you want to return to
1760 the latest generation after @code{--roll-back}, use
1761 @code{--switch-generation=+1}.
1763 The difference between @code{--roll-back} and
1764 @code{--switch-generation=-1} is that @code{--switch-generation} will
1765 not make a zeroth generation, so if a specified generation does not
1766 exist, the current generation will not be changed.
1768 @item --search-paths[=@var{kind}]
1769 @cindex search paths
1770 Report environment variable definitions, in Bash syntax, that may be
1771 needed in order to use the set of installed packages. These environment
1772 variables are used to specify @dfn{search paths} for files used by some
1773 of the installed packages.
1775 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1776 environment variables to be defined so it can look for headers and
1777 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1778 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1779 library are installed in the profile, then @code{--search-paths} will
1780 suggest setting these variables to @code{@var{profile}/include} and
1781 @code{@var{profile}/lib}, respectively.
1783 The typical use case is to define these environment variables in the
1787 $ eval `guix package --search-paths`
1790 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1791 meaning that the returned environment variable definitions will either
1792 be exact settings, or prefixes or suffixes of the current value of these
1793 variables. When omitted, @var{kind} defaults to @code{exact}.
1795 This option can also be used to compute the @emph{combined} search paths
1796 of several profiles. Consider this example:
1799 $ guix package -p foo -i guile
1800 $ guix package -p bar -i guile-json
1801 $ guix package -p foo -p bar --search-paths
1804 The last command above reports about the @code{GUILE_LOAD_PATH}
1805 variable, even though, taken individually, neither @file{foo} nor
1806 @file{bar} would lead to that recommendation.
1809 @item --profile=@var{profile}
1810 @itemx -p @var{profile}
1811 Use @var{profile} instead of the user's default profile.
1814 Produce verbose output. In particular, emit the build log of the
1815 environment on the standard error port.
1818 Use the bootstrap Guile to build the profile. This option is only
1819 useful to distribution developers.
1823 In addition to these actions, @command{guix package} supports the
1824 following options to query the current state of a profile, or the
1825 availability of packages:
1829 @item --search=@var{regexp}
1830 @itemx -s @var{regexp}
1831 @cindex searching for packages
1832 List the available packages whose name, synopsis, or description matches
1833 @var{regexp}. Print all the metadata of matching packages in
1834 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1835 GNU recutils manual}).
1837 This allows specific fields to be extracted using the @command{recsel}
1838 command, for instance:
1841 $ guix package -s malloc | recsel -p name,version
1849 Similarly, to show the name of all the packages available under the
1850 terms of the GNU@tie{}LGPL version 3:
1853 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1860 It is also possible to refine search results using several @code{-s}
1861 flags. For example, the following command returns a list of board
1865 $ guix package -s '\<board\>' -s game | recsel -p name
1870 If we were to omit @code{-s game}, we would also get software packages
1871 that deal with printed circuit boards; removing the angle brackets
1872 around @code{board} would further add packages that have to do with
1875 And now for a more elaborate example. The following command searches
1876 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1877 libraries, and prints the name and synopsis of the matching packages:
1880 $ guix package -s crypto -s library | \
1881 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1885 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1886 information on @dfn{selection expressions} for @code{recsel -e}.
1888 @item --show=@var{package}
1889 Show details about @var{package}, taken from the list of available packages, in
1890 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1894 $ guix package --show=python | recsel -p name,version
1902 You may also specify the full name of a package to only get details about a
1903 specific version of it:
1905 $ guix package --show=python@@3.4 | recsel -p name,version
1912 @item --list-installed[=@var{regexp}]
1913 @itemx -I [@var{regexp}]
1914 List the currently installed packages in the specified profile, with the
1915 most recently installed packages shown last. When @var{regexp} is
1916 specified, list only installed packages whose name matches @var{regexp}.
1918 For each installed package, print the following items, separated by
1919 tabs: the package name, its version string, the part of the package that
1920 is installed (for instance, @code{out} for the default output,
1921 @code{include} for its headers, etc.), and the path of this package in
1924 @item --list-available[=@var{regexp}]
1925 @itemx -A [@var{regexp}]
1926 List packages currently available in the distribution for this system
1927 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1928 installed packages whose name matches @var{regexp}.
1930 For each package, print the following items separated by tabs: its name,
1931 its version string, the parts of the package (@pxref{Packages with
1932 Multiple Outputs}), and the source location of its definition.
1934 @item --list-generations[=@var{pattern}]
1935 @itemx -l [@var{pattern}]
1937 Return a list of generations along with their creation dates; for each
1938 generation, show the installed packages, with the most recently
1939 installed packages shown last. Note that the zeroth generation is never
1942 For each installed package, print the following items, separated by
1943 tabs: the name of a package, its version string, the part of the package
1944 that is installed (@pxref{Packages with Multiple Outputs}), and the
1945 location of this package in the store.
1947 When @var{pattern} is used, the command returns only matching
1948 generations. Valid patterns include:
1951 @item @emph{Integers and comma-separated integers}. Both patterns denote
1952 generation numbers. For instance, @code{--list-generations=1} returns
1955 And @code{--list-generations=1,8,2} outputs three generations in the
1956 specified order. Neither spaces nor trailing commas are allowed.
1958 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1959 specified generations and everything in between. Note that the start of
1960 a range must be smaller than its end.
1962 It is also possible to omit the endpoint. For example,
1963 @code{--list-generations=2..}, returns all generations starting from the
1966 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1967 or months by passing an integer along with the first letter of the
1968 duration. For example, @code{--list-generations=20d} lists generations
1969 that are up to 20 days old.
1972 @item --delete-generations[=@var{pattern}]
1973 @itemx -d [@var{pattern}]
1974 When @var{pattern} is omitted, delete all generations except the current
1977 This command accepts the same patterns as @option{--list-generations}.
1978 When @var{pattern} is specified, delete the matching generations. When
1979 @var{pattern} specifies a duration, generations @emph{older} than the
1980 specified duration match. For instance, @code{--delete-generations=1m}
1981 deletes generations that are more than one month old.
1983 If the current generation matches, it is @emph{not} deleted. Also, the
1984 zeroth generation is never deleted.
1986 Note that deleting generations prevents rolling back to them.
1987 Consequently, this command must be used with care.
1991 Finally, since @command{guix package} may actually start build
1992 processes, it supports all the common build options (@pxref{Common Build
1993 Options}). It also supports package transformation options, such as
1994 @option{--with-source} (@pxref{Package Transformation Options}).
1995 However, note that package transformations are lost when upgrading; to
1996 preserve transformations across upgrades, you should define your own
1997 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1998 (@pxref{Defining Packages}).
2002 @section Substitutes
2005 @cindex pre-built binaries
2006 Guix supports transparent source/binary deployment, which means that it
2007 can either build things locally, or download pre-built items from a
2008 server. We call these pre-built items @dfn{substitutes}---they are
2009 substitutes for local build results. In many cases, downloading a
2010 substitute is much faster than building things locally.
2012 Substitutes can be anything resulting from a derivation build
2013 (@pxref{Derivations}). Of course, in the common case, they are
2014 pre-built package binaries, but source tarballs, for instance, which
2015 also result from derivation builds, can be available as substitutes.
2017 The @code{hydra.gnu.org} server is a front-end to a build farm that
2018 builds packages from the GNU distribution continuously for some
2019 architectures, and makes them available as substitutes. This is the
2020 default source of substitutes; it can be overridden by passing the
2021 @option{--substitute-urls} option either to @command{guix-daemon}
2022 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2023 or to client tools such as @command{guix package}
2024 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2027 Substitute URLs can be either HTTP or HTTPS.
2028 HTTPS is recommended because communications are encrypted; conversely,
2029 using HTTP makes all communications visible to an eavesdropper, who
2030 could use the information gathered to determine, for instance, whether
2031 your system has unpatched security vulnerabilities.
2034 @cindex digital signatures
2035 @cindex substitutes, authorization thereof
2036 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2038 must add its public key to the access control list (ACL) of archive
2039 imports, using the @command{guix archive} command (@pxref{Invoking guix
2040 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2041 be compromised and to serve genuine substitutes.
2043 This public key is installed along with Guix, in
2044 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2045 the installation prefix of Guix. If you installed Guix from source,
2046 make sure you checked the GPG signature of
2047 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2048 Then, you can run something like this:
2051 # guix archive --authorize < hydra.gnu.org.pub
2054 Once this is in place, the output of a command like @code{guix build}
2055 should change from something like:
2058 $ guix build emacs --dry-run
2059 The following derivations would be built:
2060 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2061 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2062 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2063 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2071 $ guix build emacs --dry-run
2072 The following files would be downloaded:
2073 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2074 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2075 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2076 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2081 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2082 will be downloaded, when possible, for future builds.
2084 Guix ignores substitutes that are not signed, or that are not signed by
2085 one of the keys listed in the ACL. It also detects and raises an error
2086 when attempting to use a substitute that has been tampered with.
2089 Substitutes are downloaded over HTTP or HTTPS.
2090 The @code{http_proxy} environment
2091 variable can be set in the environment of @command{guix-daemon} and is
2092 honored for downloads of substitutes. Note that the value of
2093 @code{http_proxy} in the environment where @command{guix build},
2094 @command{guix package}, and other client commands are run has
2095 @emph{absolutely no effect}.
2097 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2098 (in other words, the server is not authenticated), contrary to what
2099 HTTPS clients such as Web browsers usually do. This is because Guix
2100 authenticates substitute information itself, as explained above, which
2101 is what we care about (whereas X.509 certificates are about
2102 authenticating bindings between domain names and public keys.)
2104 The substitute mechanism can be disabled globally by running
2105 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2106 guix-daemon}). It can also be disabled temporarily by passing the
2107 @code{--no-substitutes} option to @command{guix package}, @command{guix
2108 build}, and other command-line tools.
2111 @unnumberedsubsec On Trusting Binaries
2113 Today, each individual's control over their own computing is at the
2114 mercy of institutions, corporations, and groups with enough power and
2115 determination to subvert the computing infrastructure and exploit its
2116 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2117 convenient, we encourage users to also build on their own, or even run
2118 their own build farm, such that @code{hydra.gnu.org} is less of an
2119 interesting target. One way to help is by publishing the software you
2120 build using @command{guix publish} so that others have one more choice
2121 of server to download substitutes from (@pxref{Invoking guix publish}).
2123 Guix has the foundations to maximize build reproducibility
2124 (@pxref{Features}). In most cases, independent builds of a given
2125 package or derivation should yield bit-identical results. Thus, through
2126 a diverse set of independent package builds, we can strengthen the
2127 integrity of our systems. The @command{guix challenge} command aims to
2128 help users assess substitute servers, and to assist developers in
2129 finding out about non-deterministic package builds (@pxref{Invoking guix
2130 challenge}). Similarly, the @option{--check} option of @command{guix
2131 build} allows users to check whether previously-installed substitutes
2132 are genuine by rebuilding them locally (@pxref{build-check,
2133 @command{guix build --check}}).
2135 In the future, we want Guix to have support to publish and retrieve
2136 binaries to/from other users, in a peer-to-peer fashion. If you would
2137 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2140 @node Packages with Multiple Outputs
2141 @section Packages with Multiple Outputs
2143 @cindex multiple-output packages
2144 @cindex package outputs
2147 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2148 source package leads to exactly one directory in the store. When running
2149 @command{guix package -i glibc}, one installs the default output of the
2150 GNU libc package; the default output is called @code{out}, but its name
2151 can be omitted as shown in this command. In this particular case, the
2152 default output of @code{glibc} contains all the C header files, shared
2153 libraries, static libraries, Info documentation, and other supporting
2156 Sometimes it is more appropriate to separate the various types of files
2157 produced from a single source package into separate outputs. For
2158 instance, the GLib C library (used by GTK+ and related packages)
2159 installs more than 20 MiB of reference documentation as HTML pages.
2160 To save space for users who do not need it, the documentation goes to a
2161 separate output, called @code{doc}. To install the main GLib output,
2162 which contains everything but the documentation, one would run:
2165 guix package -i glib
2168 @cindex documentation
2169 The command to install its documentation is:
2172 guix package -i glib:doc
2175 Some packages install programs with different ``dependency footprints''.
2176 For instance, the WordNet package installs both command-line tools and
2177 graphical user interfaces (GUIs). The former depend solely on the C
2178 library, whereas the latter depend on Tcl/Tk and the underlying X
2179 libraries. In this case, we leave the command-line tools in the default
2180 output, whereas the GUIs are in a separate output. This allows users
2181 who do not need the GUIs to save space. The @command{guix size} command
2182 can help find out about such situations (@pxref{Invoking guix size}).
2183 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2185 There are several such multiple-output packages in the GNU distribution.
2186 Other conventional output names include @code{lib} for libraries and
2187 possibly header files, @code{bin} for stand-alone programs, and
2188 @code{debug} for debugging information (@pxref{Installing Debugging
2189 Files}). The outputs of a packages are listed in the third column of
2190 the output of @command{guix package --list-available} (@pxref{Invoking
2194 @node Invoking guix gc
2195 @section Invoking @command{guix gc}
2197 @cindex garbage collector
2199 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2200 The @command{guix gc} command allows users to explicitly run the garbage
2201 collector to reclaim space from the @file{/gnu/store} directory. It is
2202 the @emph{only} way to remove files from @file{/gnu/store}---removing
2203 files or directories manually may break it beyond repair!
2205 The garbage collector has a set of known @dfn{roots}: any file under
2206 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2207 cannot be deleted; any other file is considered @dfn{dead} and may be
2208 deleted. The set of garbage collector roots includes default user
2209 profiles, and may be augmented with @command{guix build --root}, for
2210 example (@pxref{Invoking guix build}).
2212 Prior to running @code{guix gc --collect-garbage} to make space, it is
2213 often useful to remove old generations from user profiles; that way, old
2214 package builds referenced by those generations can be reclaimed. This
2215 is achieved by running @code{guix package --delete-generations}
2216 (@pxref{Invoking guix package}).
2218 The @command{guix gc} command has three modes of operation: it can be
2219 used to garbage-collect any dead files (the default), to delete specific
2220 files (the @code{--delete} option), to print garbage-collector
2221 information, or for more advanced queries. The garbage collection
2222 options are as follows:
2225 @item --collect-garbage[=@var{min}]
2226 @itemx -C [@var{min}]
2227 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2228 sub-directories. This is the default operation when no option is
2231 When @var{min} is given, stop once @var{min} bytes have been collected.
2232 @var{min} may be a number of bytes, or it may include a unit as a
2233 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2234 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2236 When @var{min} is omitted, collect all the garbage.
2238 @item --free-space=@var{free}
2239 @itemx -F @var{free}
2240 Collect garbage until @var{free} space is available under
2241 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2242 as @code{500MiB}, as described above.
2244 When @var{free} or more is already available in @file{/gnu/store}, do
2245 nothing and exit immediately.
2249 Attempt to delete all the store files and directories specified as
2250 arguments. This fails if some of the files are not in the store, or if
2251 they are still live.
2253 @item --list-failures
2254 List store items corresponding to cached build failures.
2256 This prints nothing unless the daemon was started with
2257 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2258 @option{--cache-failures}}).
2260 @item --clear-failures
2261 Remove the specified store items from the failed-build cache.
2263 Again, this option only makes sense when the daemon is started with
2264 @option{--cache-failures}. Otherwise, it does nothing.
2267 Show the list of dead files and directories still present in the
2268 store---i.e., files and directories no longer reachable from any root.
2271 Show the list of live store files and directories.
2275 In addition, the references among existing store files can be queried:
2281 @cindex package dependencies
2282 List the references (respectively, the referrers) of store files given
2288 List the requisites of the store files passed as arguments. Requisites
2289 include the store files themselves, their references, and the references
2290 of these, recursively. In other words, the returned list is the
2291 @dfn{transitive closure} of the store files.
2293 @xref{Invoking guix size}, for a tool to profile the size of the closure
2294 of an element. @xref{Invoking guix graph}, for a tool to visualize
2295 the graph of references.
2299 Lastly, the following options allow you to check the integrity of the
2300 store and to control disk usage.
2304 @item --verify[=@var{options}]
2305 @cindex integrity, of the store
2306 @cindex integrity checking
2307 Verify the integrity of the store.
2309 By default, make sure that all the store items marked as valid in the
2310 database of the daemon actually exist in @file{/gnu/store}.
2312 When provided, @var{options} must be a comma-separated list containing one
2313 or more of @code{contents} and @code{repair}.
2315 When passing @option{--verify=contents}, the daemon computes the
2316 content hash of each store item and compares it against its hash in the
2317 database. Hash mismatches are reported as data corruptions. Because it
2318 traverses @emph{all the files in the store}, this command can take a
2319 long time, especially on systems with a slow disk drive.
2321 @cindex repairing the store
2322 @cindex corruption, recovering from
2323 Using @option{--verify=repair} or @option{--verify=contents,repair}
2324 causes the daemon to try to repair corrupt store items by fetching
2325 substitutes for them (@pxref{Substitutes}). Because repairing is not
2326 atomic, and thus potentially dangerous, it is available only to the
2327 system administrator. A lightweight alternative, when you know exactly
2328 which items in the store are corrupt, is @command{guix build --repair}
2329 (@pxref{Invoking guix build}).
2332 @cindex deduplication
2333 Optimize the store by hard-linking identical files---this is
2334 @dfn{deduplication}.
2336 The daemon performs deduplication after each successful build or archive
2337 import, unless it was started with @code{--disable-deduplication}
2338 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2339 this option is primarily useful when the daemon was running with
2340 @code{--disable-deduplication}.
2344 @node Invoking guix pull
2345 @section Invoking @command{guix pull}
2347 @cindex upgrading Guix
2348 @cindex updating Guix
2349 @cindex @command{guix pull}
2351 Packages are installed or upgraded to the latest version available in
2352 the distribution currently available on your local machine. To update
2353 that distribution, along with the Guix tools, you must run @command{guix
2354 pull}: the command downloads the latest Guix source code and package
2355 descriptions, and deploys it.
2357 On completion, @command{guix package} will use packages and package
2358 versions from this just-retrieved copy of Guix. Not only that, but all
2359 the Guix commands and Scheme modules will also be taken from that latest
2360 version. New @command{guix} sub-commands added by the update also
2363 Any user can update their Guix copy using @command{guix pull}, and the
2364 effect is limited to the user who run @command{guix pull}. For
2365 instance, when user @code{root} runs @command{guix pull}, this has no
2366 effect on the version of Guix that user @code{alice} sees, and vice
2367 versa@footnote{Under the hood, @command{guix pull} updates the
2368 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2369 and the @command{guix} command loads code from there. Currently, the
2370 only way to roll back an invocation of @command{guix pull} is to
2371 manually update this symlink to point to the previous Guix.}.
2373 The @command{guix pull} command is usually invoked with no arguments,
2374 but it supports the following options:
2378 Produce verbose output, writing build logs to the standard error output.
2380 @item --url=@var{url}
2381 Download the source tarball of Guix from @var{url}.
2383 By default, the tarball is taken from its canonical address at
2384 @code{gnu.org}, for the stable branch of Guix.
2386 With some Git servers, this can be used to deploy any version of Guix.
2387 For example, to download and deploy version 0.12.0 of Guix from the
2391 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2394 It can also be used to deploy arbitrary Git revisions:
2397 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2401 Use the bootstrap Guile to build the latest Guix. This option is only
2402 useful to Guix developers.
2406 @node Invoking guix pack
2407 @section Invoking @command{guix pack}
2409 Occasionally you want to pass software to people who are not (yet!)
2410 lucky enough to be using Guix. You'd tell them to run @command{guix
2411 package -i @var{something}}, but that's not possible in this case. This
2412 is where @command{guix pack} comes in.
2416 @cindex application bundle
2417 @cindex software bundle
2418 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2419 @dfn{software bundle}: it creates a tarball or some other archive
2420 containing the binaries of the software you're interested in, and all
2421 its dependencies. The resulting archive can be used on any machine that
2422 does not have Guix, and people can run the exact same binaries as those
2423 you have with Guix. The pack itself is created in a bit-reproducible
2424 fashion, so anyone can verify that it really contains the build results
2425 that you pretend to be shipping.
2427 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2428 their dependencies, you can run:
2431 $ guix pack guile emacs geiser
2433 /gnu/store/@dots{}-pack.tar.gz
2436 The result here is a tarball containing a @file{/gnu/store} directory
2437 with all the relevant packages. The resulting tarball contains a
2438 @dfn{profile} with the three packages of interest; the profile is the
2439 same as would be created by @command{guix package -i}. It is this
2440 mechanism that is used to create Guix's own standalone binary tarball
2441 (@pxref{Binary Installation}).
2443 Users of this pack would have to run
2444 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2445 find inconvenient. To work around it, you can create, say, a
2446 @file{/opt/gnu/bin} symlink to the profile:
2449 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2453 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2455 Alternatively, you can produce a pack in the Docker image format using
2456 the following command:
2459 guix pack -f docker guile emacs geiser
2463 The result is a tarball that can be passed to the @command{docker load}
2465 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2466 documentation} for more information.
2468 Several command-line options allow you to customize your pack:
2471 @item --format=@var{format}
2472 @itemx -f @var{format}
2473 Produce a pack in the given @var{format}.
2475 The available formats are:
2479 This is the default format. It produces a tarball containing all the
2480 specifies binaries and symlinks.
2483 This produces a tarball that follows the
2484 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2485 Docker Image Specification}.
2488 @item --expression=@var{expr}
2489 @itemx -e @var{expr}
2490 Consider the package @var{expr} evaluates to.
2492 This has the same purpose as the same-named option in @command{guix
2493 build} (@pxref{Additional Build Options, @code{--expression} in
2494 @command{guix build}}).
2496 @item --system=@var{system}
2497 @itemx -s @var{system}
2498 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2499 the system type of the build host.
2501 @item --target=@var{triplet}
2502 @cindex cross-compilation
2503 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2504 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2505 configuration triplets,, autoconf, Autoconf}).
2507 @item --compression=@var{tool}
2508 @itemx -C @var{tool}
2509 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2510 @code{bzip2}, @code{xz}, or @code{lzip}.
2512 @item --symlink=@var{spec}
2513 @itemx -S @var{spec}
2514 Add the symlinks specified by @var{spec} to the pack. This option can
2515 appear several times.
2517 @var{spec} has the form @code{@var{source}=@var{target}}, where
2518 @var{source} is the symlink that will be created and @var{target} is the
2521 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2522 symlink pointing to the @file{bin} sub-directory of the profile.
2524 @item --localstatedir
2525 Include the ``local state directory'', @file{/var/guix}, in the
2528 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2529 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2530 the pack means that the store is ``complete'' and manageable by Guix;
2531 not providing it pack means that the store is ``dead'': items cannot be
2532 added to it or removed from it after extraction of the pack.
2534 One use case for this is the Guix self-contained binary tarball
2535 (@pxref{Binary Installation}).
2538 In addition, @command{guix pack} supports all the common build options
2539 (@pxref{Common Build Options}) and all the package transformation
2540 options (@pxref{Package Transformation Options}).
2543 @node Invoking guix archive
2544 @section Invoking @command{guix archive}
2546 @cindex @command{guix archive}
2548 The @command{guix archive} command allows users to @dfn{export} files
2549 from the store into a single archive, and to later @dfn{import} them.
2550 In particular, it allows store files to be transferred from one machine
2551 to the store on another machine.
2553 @cindex exporting store items
2554 To export store files as an archive to standard output, run:
2557 guix archive --export @var{options} @var{specifications}...
2560 @var{specifications} may be either store file names or package
2561 specifications, as for @command{guix package} (@pxref{Invoking guix
2562 package}). For instance, the following command creates an archive
2563 containing the @code{gui} output of the @code{git} package and the main
2564 output of @code{emacs}:
2567 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2570 If the specified packages are not built yet, @command{guix archive}
2571 automatically builds them. The build process may be controlled with the
2572 common build options (@pxref{Common Build Options}).
2574 To transfer the @code{emacs} package to a machine connected over SSH,
2578 guix archive --export -r emacs | ssh the-machine guix archive --import
2582 Similarly, a complete user profile may be transferred from one machine
2583 to another like this:
2586 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2587 ssh the-machine guix-archive --import
2591 However, note that, in both examples, all of @code{emacs} and the
2592 profile as well as all of their dependencies are transferred (due to
2593 @code{-r}), regardless of what is already available in the store on the
2594 target machine. The @code{--missing} option can help figure out which
2595 items are missing from the target store. The @command{guix copy}
2596 command simplifies and optimizes this whole process, so this is probably
2597 what you should use in this case (@pxref{Invoking guix copy}).
2599 @cindex nar, archive format
2600 @cindex normalized archive (nar)
2601 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2602 comparable in spirit to `tar', but with differences
2603 that make it more appropriate for our purposes. First, rather than
2604 recording all Unix metadata for each file, the nar format only mentions
2605 the file type (regular, directory, or symbolic link); Unix permissions
2606 and owner/group are dismissed. Second, the order in which directory
2607 entries are stored always follows the order of file names according to
2608 the C locale collation order. This makes archive production fully
2611 When exporting, the daemon digitally signs the contents of the archive,
2612 and that digital signature is appended. When importing, the daemon
2613 verifies the signature and rejects the import in case of an invalid
2614 signature or if the signing key is not authorized.
2615 @c FIXME: Add xref to daemon doc about signatures.
2617 The main options are:
2621 Export the specified store files or packages (see below.) Write the
2622 resulting archive to the standard output.
2624 Dependencies are @emph{not} included in the output, unless
2625 @code{--recursive} is passed.
2629 When combined with @code{--export}, this instructs @command{guix
2630 archive} to include dependencies of the given items in the archive.
2631 Thus, the resulting archive is self-contained: it contains the closure
2632 of the exported store items.
2635 Read an archive from the standard input, and import the files listed
2636 therein into the store. Abort if the archive has an invalid digital
2637 signature, or if it is signed by a public key not among the authorized
2638 keys (see @code{--authorize} below.)
2641 Read a list of store file names from the standard input, one per line,
2642 and write on the standard output the subset of these files missing from
2645 @item --generate-key[=@var{parameters}]
2646 @cindex signing, archives
2647 Generate a new key pair for the daemon. This is a prerequisite before
2648 archives can be exported with @code{--export}. Note that this operation
2649 usually takes time, because it needs to gather enough entropy to
2650 generate the key pair.
2652 The generated key pair is typically stored under @file{/etc/guix}, in
2653 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2654 key, which must be kept secret.) When @var{parameters} is omitted,
2655 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2656 versions before 1.6.0, it is a 4096-bit RSA key.
2657 Alternatively, @var{parameters} can specify
2658 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2659 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2660 Libgcrypt Reference Manual}).
2663 @cindex authorizing, archives
2664 Authorize imports signed by the public key passed on standard input.
2665 The public key must be in ``s-expression advanced format''---i.e., the
2666 same format as the @file{signing-key.pub} file.
2668 The list of authorized keys is kept in the human-editable file
2669 @file{/etc/guix/acl}. The file contains
2670 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2671 s-expressions''} and is structured as an access-control list in the
2672 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2675 @item --extract=@var{directory}
2676 @itemx -x @var{directory}
2677 Read a single-item archive as served by substitute servers
2678 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2679 low-level operation needed in only very narrow use cases; see below.
2681 For example, the following command extracts the substitute for Emacs
2682 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2686 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2687 | bunzip2 | guix archive -x /tmp/emacs
2690 Single-item archives are different from multiple-item archives produced
2691 by @command{guix archive --export}; they contain a single store item,
2692 and they do @emph{not} embed a signature. Thus this operation does
2693 @emph{no} signature verification and its output should be considered
2696 The primary purpose of this operation is to facilitate inspection of
2697 archive contents coming from possibly untrusted substitute servers.
2701 @c *********************************************************************
2702 @node Programming Interface
2703 @chapter Programming Interface
2705 GNU Guix provides several Scheme programming interfaces (APIs) to
2706 define, build, and query packages. The first interface allows users to
2707 write high-level package definitions. These definitions refer to
2708 familiar packaging concepts, such as the name and version of a package,
2709 its build system, and its dependencies. These definitions can then be
2710 turned into concrete build actions.
2712 Build actions are performed by the Guix daemon, on behalf of users. In a
2713 standard setup, the daemon has write access to the store---the
2714 @file{/gnu/store} directory---whereas users do not. The recommended
2715 setup also has the daemon perform builds in chroots, under a specific
2716 build users, to minimize interference with the rest of the system.
2719 Lower-level APIs are available to interact with the daemon and the
2720 store. To instruct the daemon to perform a build action, users actually
2721 provide it with a @dfn{derivation}. A derivation is a low-level
2722 representation of the build actions to be taken, and the environment in
2723 which they should occur---derivations are to package definitions what
2724 assembly is to C programs. The term ``derivation'' comes from the fact
2725 that build results @emph{derive} from them.
2727 This chapter describes all these APIs in turn, starting from high-level
2728 package definitions.
2731 * Defining Packages:: Defining new packages.
2732 * Build Systems:: Specifying how packages are built.
2733 * The Store:: Manipulating the package store.
2734 * Derivations:: Low-level interface to package derivations.
2735 * The Store Monad:: Purely functional interface to the store.
2736 * G-Expressions:: Manipulating build expressions.
2739 @node Defining Packages
2740 @section Defining Packages
2742 The high-level interface to package definitions is implemented in the
2743 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2744 example, the package definition, or @dfn{recipe}, for the GNU Hello
2745 package looks like this:
2748 (define-module (gnu packages hello)
2749 #:use-module (guix packages)
2750 #:use-module (guix download)
2751 #:use-module (guix build-system gnu)
2752 #:use-module (guix licenses)
2753 #:use-module (gnu packages gawk))
2755 (define-public hello
2761 (uri (string-append "mirror://gnu/hello/hello-" version
2765 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2766 (build-system gnu-build-system)
2767 (arguments '(#:configure-flags '("--enable-silent-rules")))
2768 (inputs `(("gawk" ,gawk)))
2769 (synopsis "Hello, GNU world: An example GNU package")
2770 (description "Guess what GNU Hello prints!")
2771 (home-page "http://www.gnu.org/software/hello/")
2776 Without being a Scheme expert, the reader may have guessed the meaning
2777 of the various fields here. This expression binds the variable
2778 @code{hello} to a @code{<package>} object, which is essentially a record
2779 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2780 This package object can be inspected using procedures found in the
2781 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2782 returns---surprise!---@code{"hello"}.
2784 With luck, you may be able to import part or all of the definition of
2785 the package you are interested in from another repository, using the
2786 @code{guix import} command (@pxref{Invoking guix import}).
2788 In the example above, @var{hello} is defined in a module of its own,
2789 @code{(gnu packages hello)}. Technically, this is not strictly
2790 necessary, but it is convenient to do so: all the packages defined in
2791 modules under @code{(gnu packages @dots{})} are automatically known to
2792 the command-line tools (@pxref{Package Modules}).
2794 There are a few points worth noting in the above package definition:
2798 The @code{source} field of the package is an @code{<origin>} object
2799 (@pxref{origin Reference}, for the complete reference).
2800 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2801 meaning that the source is a file to be downloaded over FTP or HTTP.
2803 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2804 the GNU mirrors defined in @code{(guix download)}.
2806 The @code{sha256} field specifies the expected SHA256 hash of the file
2807 being downloaded. It is mandatory, and allows Guix to check the
2808 integrity of the file. The @code{(base32 @dots{})} form introduces the
2809 base32 representation of the hash. You can obtain this information with
2810 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2811 hash} (@pxref{Invoking guix hash}).
2814 When needed, the @code{origin} form can also have a @code{patches} field
2815 listing patches to be applied, and a @code{snippet} field giving a
2816 Scheme expression to modify the source code.
2819 @cindex GNU Build System
2820 The @code{build-system} field specifies the procedure to build the
2821 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2822 represents the familiar GNU Build System, where packages may be
2823 configured, built, and installed with the usual @code{./configure &&
2824 make && make check && make install} command sequence.
2827 The @code{arguments} field specifies options for the build system
2828 (@pxref{Build Systems}). Here it is interpreted by
2829 @var{gnu-build-system} as a request run @file{configure} with the
2830 @code{--enable-silent-rules} flag.
2836 What about these quote (@code{'}) characters? They are Scheme syntax to
2837 introduce a literal list; @code{'} is synonymous with @code{quote}.
2838 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2839 for details. Here the value of the @code{arguments} field is a list of
2840 arguments passed to the build system down the road, as with @code{apply}
2841 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2844 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2845 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2846 @code{#:configure-flags} is a keyword used to pass a keyword argument
2847 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2851 The @code{inputs} field specifies inputs to the build process---i.e.,
2852 build-time or run-time dependencies of the package. Here, we define an
2853 input called @code{"gawk"} whose value is that of the @var{gawk}
2854 variable; @var{gawk} is itself bound to a @code{<package>} object.
2856 @cindex backquote (quasiquote)
2859 @cindex comma (unquote)
2863 @findex unquote-splicing
2864 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2865 us to introduce a literal list in the @code{inputs} field, while
2866 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2867 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2870 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2871 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2872 of ensuring that they are present (@pxref{Build Systems}).
2874 However, any other dependencies need to be specified in the
2875 @code{inputs} field. Any dependency not specified here will simply be
2876 unavailable to the build process, possibly leading to a build failure.
2879 @xref{package Reference}, for a full description of possible fields.
2881 Once a package definition is in place, the
2882 package may actually be built using the @code{guix build} command-line
2883 tool (@pxref{Invoking guix build}), troubleshooting any build failures
2884 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
2885 package definition using the @command{guix edit} command
2886 (@pxref{Invoking guix edit}).
2887 @xref{Packaging Guidelines}, for
2888 more information on how to test package definitions, and
2889 @ref{Invoking guix lint}, for information on how to check a definition
2890 for style conformance.
2892 Finally, updating the package definition to a new upstream version
2893 can be partly automated by the @command{guix refresh} command
2894 (@pxref{Invoking guix refresh}).
2896 Behind the scenes, a derivation corresponding to the @code{<package>}
2897 object is first computed by the @code{package-derivation} procedure.
2898 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2899 The build actions it prescribes may then be realized by using the
2900 @code{build-derivations} procedure (@pxref{The Store}).
2902 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2903 Return the @code{<derivation>} object of @var{package} for @var{system}
2904 (@pxref{Derivations}).
2906 @var{package} must be a valid @code{<package>} object, and @var{system}
2907 must be a string denoting the target system type---e.g.,
2908 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2909 must be a connection to the daemon, which operates on the store
2910 (@pxref{The Store}).
2914 @cindex cross-compilation
2915 Similarly, it is possible to compute a derivation that cross-builds a
2916 package for some other system:
2918 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2919 @var{package} @var{target} [@var{system}]
2920 Return the @code{<derivation>} object of @var{package} cross-built from
2921 @var{system} to @var{target}.
2923 @var{target} must be a valid GNU triplet denoting the target hardware
2924 and operating system, such as @code{"mips64el-linux-gnu"}
2925 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2926 Configure and Build System}).
2929 @cindex package transformations
2930 @cindex input rewriting
2931 @cindex dependency tree rewriting
2932 Packages can be manipulated in arbitrary ways. An example of a useful
2933 transformation is @dfn{input rewriting}, whereby the dependency tree of
2934 a package is rewritten by replacing specific inputs by others:
2936 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2937 [@var{rewrite-name}]
2938 Return a procedure that, when passed a package, replaces its direct and
2939 indirect dependencies (but not its implicit inputs) according to
2940 @var{replacements}. @var{replacements} is a list of package pairs; the
2941 first element of each pair is the package to replace, and the second one
2944 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2945 the name of a package and returns its new name after rewrite.
2949 Consider this example:
2952 (define libressl-instead-of-openssl
2953 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2955 (package-input-rewriting `((,openssl . ,libressl))))
2957 (define git-with-libressl
2958 (libressl-instead-of-openssl git))
2962 Here we first define a rewriting procedure that replaces @var{openssl}
2963 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2964 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2965 This is exactly what the @option{--with-input} command-line option does
2966 (@pxref{Package Transformation Options, @option{--with-input}}).
2968 A more generic procedure to rewrite a package dependency graph is
2969 @code{package-mapping}: it supports arbitrary changes to nodes in the
2972 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
2973 Return a procedure that, given a package, applies @var{proc} to all the packages
2974 depended on and returns the resulting package. The procedure stops recursion
2975 when @var{cut?} returns true for a given package.
2979 * package Reference :: The package data type.
2980 * origin Reference:: The origin data type.
2984 @node package Reference
2985 @subsection @code{package} Reference
2987 This section summarizes all the options available in @code{package}
2988 declarations (@pxref{Defining Packages}).
2990 @deftp {Data Type} package
2991 This is the data type representing a package recipe.
2995 The name of the package, as a string.
2997 @item @code{version}
2998 The version of the package, as a string.
3001 An object telling how the source code for the package should be
3002 acquired. Most of the time, this is an @code{origin} object, which
3003 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3004 can also be any other ``file-like'' object such as a @code{local-file},
3005 which denotes a file from the local file system (@pxref{G-Expressions,
3006 @code{local-file}}).
3008 @item @code{build-system}
3009 The build system that should be used to build the package (@pxref{Build
3012 @item @code{arguments} (default: @code{'()})
3013 The arguments that should be passed to the build system. This is a
3014 list, typically containing sequential keyword-value pairs.
3016 @item @code{inputs} (default: @code{'()})
3017 @itemx @code{native-inputs} (default: @code{'()})
3018 @itemx @code{propagated-inputs} (default: @code{'()})
3019 @cindex inputs, of packages
3020 These fields list dependencies of the package. Each one is a list of
3021 tuples, where each tuple has a label for the input (a string) as its
3022 first element, a package, origin, or derivation as its second element,
3023 and optionally the name of the output thereof that should be used, which
3024 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3025 more on package outputs). For example, the list below specifies three
3029 `(("libffi" ,libffi)
3030 ("libunistring" ,libunistring)
3031 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3034 @cindex cross compilation, package dependencies
3035 The distinction between @code{native-inputs} and @code{inputs} is
3036 necessary when considering cross-compilation. When cross-compiling,
3037 dependencies listed in @code{inputs} are built for the @emph{target}
3038 architecture; conversely, dependencies listed in @code{native-inputs}
3039 are built for the architecture of the @emph{build} machine.
3041 @code{native-inputs} is typically used to list tools needed at
3042 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3043 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3044 this area (@pxref{Invoking guix lint}).
3046 @anchor{package-propagated-inputs}
3047 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3048 specified packages will be automatically installed alongside the package
3049 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3050 package}}, for information on how @command{guix package} deals with
3053 For example this is necessary when a C/C++ library needs headers of
3054 another library to compile, or when a pkg-config file refers to another
3055 one @i{via} its @code{Requires} field.
3057 Another example where @code{propagated-inputs} is useful is for languages
3058 that lack a facility to record the run-time search path akin to the
3059 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3060 more. To ensure that libraries written in those languages can find
3061 library code they depend on at run time, run-time dependencies must be
3062 listed in @code{propagated-inputs} rather than @code{inputs}.
3064 @item @code{self-native-input?} (default: @code{#f})
3065 This is a Boolean field telling whether the package should use itself as
3066 a native input when cross-compiling.
3068 @item @code{outputs} (default: @code{'("out")})
3069 The list of output names of the package. @xref{Packages with Multiple
3070 Outputs}, for typical uses of additional outputs.
3072 @item @code{native-search-paths} (default: @code{'()})
3073 @itemx @code{search-paths} (default: @code{'()})
3074 A list of @code{search-path-specification} objects describing
3075 search-path environment variables honored by the package.
3077 @item @code{replacement} (default: @code{#f})
3078 This must be either @code{#f} or a package object that will be used as a
3079 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3082 @item @code{synopsis}
3083 A one-line description of the package.
3085 @item @code{description}
3086 A more elaborate description of the package.
3088 @item @code{license}
3089 @cindex license, of packages
3090 The license of the package; a value from @code{(guix licenses)},
3091 or a list of such values.
3093 @item @code{home-page}
3094 The URL to the home-page of the package, as a string.
3096 @item @code{supported-systems} (default: @var{%supported-systems})
3097 The list of systems supported by the package, as strings of the form
3098 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3100 @item @code{maintainers} (default: @code{'()})
3101 The list of maintainers of the package, as @code{maintainer} objects.
3103 @item @code{location} (default: source location of the @code{package} form)
3104 The source location of the package. It is useful to override this when
3105 inheriting from another package, in which case this field is not
3106 automatically corrected.
3111 @node origin Reference
3112 @subsection @code{origin} Reference
3114 This section summarizes all the options available in @code{origin}
3115 declarations (@pxref{Defining Packages}).
3117 @deftp {Data Type} origin
3118 This is the data type representing a source code origin.
3122 An object containing the URI of the source. The object type depends on
3123 the @code{method} (see below). For example, when using the
3124 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3125 values are: a URL represented as a string, or a list thereof.
3128 A procedure that handles the URI.
3133 @item @var{url-fetch} from @code{(guix download)}
3134 download a file from the HTTP, HTTPS, or FTP URL specified in the
3138 @item @var{git-fetch} from @code{(guix git-download)}
3139 clone the Git version control repository, and check out the revision
3140 specified in the @code{uri} field as a @code{git-reference} object; a
3141 @code{git-reference} looks like this:
3145 (url "git://git.debian.org/git/pkg-shadow/shadow")
3146 (commit "v4.1.5.1"))
3151 A bytevector containing the SHA-256 hash of the source. Typically the
3152 @code{base32} form is used here to generate the bytevector from a
3155 You can obtain this information using @code{guix download}
3156 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3159 @item @code{file-name} (default: @code{#f})
3160 The file name under which the source code should be saved. When this is
3161 @code{#f}, a sensible default value will be used in most cases. In case
3162 the source is fetched from a URL, the file name from the URL will be
3163 used. For version control checkouts, it is recommended to provide the
3164 file name explicitly because the default is not very descriptive.
3166 @item @code{patches} (default: @code{'()})
3167 A list of file names containing patches to be applied to the source.
3169 This list of patches must be unconditional. In particular, it cannot
3170 depend on the value of @code{%current-system} or
3171 @code{%current-target-system}.
3173 @item @code{snippet} (default: @code{#f})
3174 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3175 in the source directory. This is a convenient way to modify the source,
3176 sometimes more convenient than a patch.
3178 @item @code{patch-flags} (default: @code{'("-p1")})
3179 A list of command-line flags that should be passed to the @code{patch}
3182 @item @code{patch-inputs} (default: @code{#f})
3183 Input packages or derivations to the patching process. When this is
3184 @code{#f}, the usual set of inputs necessary for patching are provided,
3185 such as GNU@tie{}Patch.
3187 @item @code{modules} (default: @code{'()})
3188 A list of Guile modules that should be loaded during the patching
3189 process and while running the code in the @code{snippet} field.
3191 @item @code{patch-guile} (default: @code{#f})
3192 The Guile package that should be used in the patching process. When
3193 this is @code{#f}, a sensible default is used.
3199 @section Build Systems
3201 @cindex build system
3202 Each package definition specifies a @dfn{build system} and arguments for
3203 that build system (@pxref{Defining Packages}). This @code{build-system}
3204 field represents the build procedure of the package, as well as implicit
3205 dependencies of that build procedure.
3207 Build systems are @code{<build-system>} objects. The interface to
3208 create and manipulate them is provided by the @code{(guix build-system)}
3209 module, and actual build systems are exported by specific modules.
3211 @cindex bag (low-level package representation)
3212 Under the hood, build systems first compile package objects to
3213 @dfn{bags}. A @dfn{bag} is like a package, but with less
3214 ornamentation---in other words, a bag is a lower-level representation of
3215 a package, which includes all the inputs of that package, including some
3216 that were implicitly added by the build system. This intermediate
3217 representation is then compiled to a derivation (@pxref{Derivations}).
3219 Build systems accept an optional list of @dfn{arguments}. In package
3220 definitions, these are passed @i{via} the @code{arguments} field
3221 (@pxref{Defining Packages}). They are typically keyword arguments
3222 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3223 Guile Reference Manual}). The value of these arguments is usually
3224 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3225 by the daemon (@pxref{Derivations}).
3227 The main build system is @var{gnu-build-system}, which implements the
3228 standard build procedure for GNU and many other packages. It
3229 is provided by the @code{(guix build-system gnu)} module.
3231 @defvr {Scheme Variable} gnu-build-system
3232 @var{gnu-build-system} represents the GNU Build System, and variants
3233 thereof (@pxref{Configuration, configuration and makefile conventions,,
3234 standards, GNU Coding Standards}).
3236 @cindex build phases
3237 In a nutshell, packages using it are configured, built, and installed with
3238 the usual @code{./configure && make && make check && make install}
3239 command sequence. In practice, a few additional steps are often needed.
3240 All these steps are split up in separate @dfn{phases},
3241 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3242 modules for more details about the build phases.}:
3246 Unpack the source tarball, and change the current directory to the
3247 extracted source tree. If the source is actually a directory, copy it
3248 to the build tree, and enter that directory.
3250 @item patch-source-shebangs
3251 Patch shebangs encountered in source files so they refer to the right
3252 store file names. For instance, this changes @code{#!/bin/sh} to
3253 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3256 Run the @file{configure} script with a number of default options, such
3257 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3258 by the @code{#:configure-flags} argument.
3261 Run @code{make} with the list of flags specified with
3262 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3263 (the default), build with @code{make -j}.
3266 Run @code{make check}, or some other target specified with
3267 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3268 @code{#:parallel-tests?} argument is true (the default), run @code{make
3272 Run @code{make install} with the flags listed in @code{#:make-flags}.
3274 @item patch-shebangs
3275 Patch shebangs on the installed executable files.
3278 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3279 is false), copying them to the @code{debug} output when available
3280 (@pxref{Installing Debugging Files}).
3283 @vindex %standard-phases
3284 The build-side module @code{(guix build gnu-build-system)} defines
3285 @var{%standard-phases} as the default list of build phases.
3286 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3287 procedure implements the actual phase.
3289 The list of phases used for a particular package can be changed with the
3290 @code{#:phases} parameter. For instance, passing:
3293 #:phases (modify-phases %standard-phases (delete 'configure))
3296 means that all the phases described above will be used, except the
3297 @code{configure} phase.
3299 In addition, this build system ensures that the ``standard'' environment
3300 for GNU packages is available. This includes tools such as GCC, libc,
3301 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3302 build-system gnu)} module for a complete list). We call these the
3303 @dfn{implicit inputs} of a package, because package definitions do not
3304 have to mention them.
3307 Other @code{<build-system>} objects are defined to support other
3308 conventions and tools used by free software packages. They inherit most
3309 of @var{gnu-build-system}, and differ mainly in the set of inputs
3310 implicitly added to the build process, and in the list of phases
3311 executed. Some of these build systems are listed below.
3313 @defvr {Scheme Variable} ant-build-system
3314 This variable is exported by @code{(guix build-system ant)}. It
3315 implements the build procedure for Java packages that can be built with
3316 @url{http://ant.apache.org/, Ant build tool}.
3318 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3319 provided by the @code{icedtea} package to the set of inputs. Different
3320 packages can be specified with the @code{#:ant} and @code{#:jdk}
3321 parameters, respectively.
3323 When the original package does not provide a suitable Ant build file,
3324 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3325 build file @file{build.xml} with tasks to build the specified jar
3328 The parameter @code{#:build-target} can be used to specify the Ant task
3329 that should be run during the @code{build} phase. By default the
3330 ``jar'' task will be run.
3334 @defvr {Scheme Variable} asdf-build-system/source
3335 @defvrx {Scheme Variable} asdf-build-system/sbcl
3336 @defvrx {Scheme Variable} asdf-build-system/ecl
3338 These variables, exported by @code{(guix build-system asdf)}, implement
3339 build procedures for Common Lisp packages using
3340 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3341 definition facility for Common Lisp programs and libraries.
3343 The @code{asdf-build-system/source} system installs the packages in
3344 source form, and can be loaded using any common lisp implementation, via
3345 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3346 systems in the format which a particular implementation understands.
3347 These build systems can also be used to produce executable programs, or
3348 lisp images which contain a set of packages pre-loaded.
3350 The build system uses naming conventions. For binary packages, the
3351 package itself as well as its run-time dependencies should begin their
3352 name with the lisp implementation, such as @code{sbcl-} for
3353 @code{asdf-build-system/sbcl}. Beginning the input name with this
3354 prefix will allow the build system to encode its location into the
3355 resulting library, so that the input can be found at run-time.
3357 If dependencies are used only for tests, it is convenient to use a
3358 different prefix in order to avoid having a run-time dependency on such
3359 systems. For example,
3362 (define-public sbcl-bordeaux-threads
3365 (native-inputs `(("tests:cl-fiveam" ,sbcl-fiveam)))
3369 Additionally, the corresponding source package should be labeled using
3370 the same convention as python packages (see @ref{Python Modules}), using
3371 the @code{cl-} prefix.
3373 For binary packages, each system should be defined as a Guix package.
3374 If one package @code{origin} contains several systems, package variants
3375 can be created in order to build all the systems. Source packages,
3376 which use @code{asdf-build-system/source}, may contain several systems.
3378 In order to create executable programs and images, the build-side
3379 procedures @code{build-program} and @code{build-image} can be used.
3380 They should be called in a build phase after the @code{create-symlinks}
3381 phase, so that the system which was just built can be used within the
3382 resulting image. @code{build-program} requires a list of Common Lisp
3383 expressions to be passed as the @code{#:entry-program} argument.
3385 If the system is not defined within its own @code{.asd} file of the same
3386 name, then the @code{#:asd-file} parameter should be used to specify
3387 which file the system is defined in.
3391 @defvr {Scheme Variable} cargo-build-system
3392 @cindex Rust programming language
3393 @cindex Cargo (Rust build system)
3394 This variable is exported by @code{(guix build-system cargo)}. It
3395 supports builds of packages using Cargo, the build tool of the
3396 @uref{https://www.rust-lang.org, Rust programming language}.
3398 In its @code{configure} phase, this build system replaces dependencies
3399 specified in the @file{Carto.toml} file with inputs to the Guix package.
3400 The @code{install} phase installs the binaries, and it also installs the
3401 source code and @file{Cargo.toml} file.
3404 @defvr {Scheme Variable} cmake-build-system
3405 This variable is exported by @code{(guix build-system cmake)}. It
3406 implements the build procedure for packages using the
3407 @url{http://www.cmake.org, CMake build tool}.
3409 It automatically adds the @code{cmake} package to the set of inputs.
3410 Which package is used can be specified with the @code{#:cmake}
3413 The @code{#:configure-flags} parameter is taken as a list of flags
3414 passed to the @command{cmake} command. The @code{#:build-type}
3415 parameter specifies in abstract terms the flags passed to the compiler;
3416 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3417 debugging information''), which roughly means that code is compiled with
3418 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3421 @defvr {Scheme Variable} glib-or-gtk-build-system
3422 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3423 is intended for use with packages making use of GLib or GTK+.
3425 This build system adds the following two phases to the ones defined by
3426 @var{gnu-build-system}:
3429 @item glib-or-gtk-wrap
3430 The phase @code{glib-or-gtk-wrap} ensures that programs in
3431 @file{bin/} are able to find GLib ``schemas'' and
3432 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3433 modules}. This is achieved by wrapping the programs in launch scripts
3434 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3435 environment variables.
3437 It is possible to exclude specific package outputs from that wrapping
3438 process by listing their names in the
3439 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3440 when an output is known not to contain any GLib or GTK+ binaries, and
3441 where wrapping would gratuitously add a dependency of that output on
3444 @item glib-or-gtk-compile-schemas
3445 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3446 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3447 GSettings schemas} of GLib are compiled. Compilation is performed by the
3448 @command{glib-compile-schemas} program. It is provided by the package
3449 @code{glib:bin} which is automatically imported by the build system.
3450 The @code{glib} package providing @command{glib-compile-schemas} can be
3451 specified with the @code{#:glib} parameter.
3454 Both phases are executed after the @code{install} phase.
3457 @defvr {Scheme Variable} ocaml-build-system
3458 This variable is exported by @code{(guix build-system ocaml)}. It implements
3459 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3460 of choosing the correct set of commands to run for each package. OCaml
3461 packages can expect many different commands to be run. This build system will
3464 When the package has a @file{setup.ml} file present at the top-level, it will
3465 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3466 @code{ocaml setup.ml -install}. The build system will assume that this file
3467 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3468 care of setting the prefix and enabling tests if they are not disabled. You
3469 can pass configure and build flags with the @code{#:configure-flags} and
3470 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3471 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3472 bypass this system in the build and install phases.
3474 When the package has a @file{configure} file, it is assumed that it is a
3475 hand-made configure script that requires a different argument format than
3476 in the @code{gnu-build-system}. You can add more flags with the
3477 @code{#:configure-flags} key.
3479 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3480 @code{#t}), it will be used and more flags can be passed to the build and
3481 install phases with the @code{#:make-flags} key.
3483 Finally, some packages do not have these files and use a somewhat standard
3484 location for its build system. In that case, the build system will run
3485 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3486 providing the path to the required findlib module. Additional flags can
3487 be passed via the @code{#:build-flags} key. Install is taken care of by
3488 @command{opam-installer}. In this case, the @code{opam} package must
3489 be added to the @code{native-inputs} field of the package definition.
3491 Note that most OCaml packages assume they will be installed in the same
3492 directory as OCaml, which is not what we want in guix. In particular, they
3493 will install @file{.so} files in their module's directory, which is usually
3494 fine because it is in the OCaml compiler directory. In guix though, these
3495 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3496 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3497 @file{.so} libraries should be installed.
3500 @defvr {Scheme Variable} python-build-system
3501 This variable is exported by @code{(guix build-system python)}. It
3502 implements the more or less standard build procedure used by Python
3503 packages, which consists in running @code{python setup.py build} and
3504 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3506 For packages that install stand-alone Python programs under @code{bin/},
3507 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3508 environment variable points to all the Python libraries they depend on.
3510 Which Python package is used to perform the build can be specified with
3511 the @code{#:python} parameter. This is a useful way to force a package
3512 to be built for a specific version of the Python interpreter, which
3513 might be necessary if the package is only compatible with a single
3514 interpreter version.
3516 By default guix calls @code{setup.py} under control of
3517 @code{setuptools}, much like @command{pip} does. Some packages are not
3518 compatible with setuptools (and pip), thus you can disable this by
3519 setting the @code{#:use-setuptools} parameter to @code{#f}.
3522 @defvr {Scheme Variable} perl-build-system
3523 This variable is exported by @code{(guix build-system perl)}. It
3524 implements the standard build procedure for Perl packages, which either
3525 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3526 followed by @code{Build} and @code{Build install}; or in running
3527 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3528 @code{make} and @code{make install}, depending on which of
3529 @code{Build.PL} or @code{Makefile.PL} is present in the package
3530 distribution. Preference is given to the former if both @code{Build.PL}
3531 and @code{Makefile.PL} exist in the package distribution. This
3532 preference can be reversed by specifying @code{#t} for the
3533 @code{#:make-maker?} parameter.
3535 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3536 passes flags specified by the @code{#:make-maker-flags} or
3537 @code{#:module-build-flags} parameter, respectively.
3539 Which Perl package is used can be specified with @code{#:perl}.
3542 @defvr {Scheme Variable} r-build-system
3543 This variable is exported by @code{(guix build-system r)}. It
3544 implements the build procedure used by @uref{http://r-project.org, R}
3545 packages, which essentially is little more than running @code{R CMD
3546 INSTALL --library=/gnu/store/@dots{}} in an environment where
3547 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3548 are run after installation using the R function
3549 @code{tools::testInstalledPackage}.
3552 @defvr {Scheme Variable} ruby-build-system
3553 This variable is exported by @code{(guix build-system ruby)}. It
3554 implements the RubyGems build procedure used by Ruby packages, which
3555 involves running @code{gem build} followed by @code{gem install}.
3557 The @code{source} field of a package that uses this build system
3558 typically references a gem archive, since this is the format that Ruby
3559 developers use when releasing their software. The build system unpacks
3560 the gem archive, potentially patches the source, runs the test suite,
3561 repackages the gem, and installs it. Additionally, directories and
3562 tarballs may be referenced to allow building unreleased gems from Git or
3563 a traditional source release tarball.
3565 Which Ruby package is used can be specified with the @code{#:ruby}
3566 parameter. A list of additional flags to be passed to the @command{gem}
3567 command can be specified with the @code{#:gem-flags} parameter.
3570 @defvr {Scheme Variable} waf-build-system
3571 This variable is exported by @code{(guix build-system waf)}. It
3572 implements a build procedure around the @code{waf} script. The common
3573 phases---@code{configure}, @code{build}, and @code{install}---are
3574 implemented by passing their names as arguments to the @code{waf}
3577 The @code{waf} script is executed by the Python interpreter. Which
3578 Python package is used to run the script can be specified with the
3579 @code{#:python} parameter.
3582 @defvr {Scheme Variable} haskell-build-system
3583 This variable is exported by @code{(guix build-system haskell)}. It
3584 implements the Cabal build procedure used by Haskell packages, which
3585 involves running @code{runhaskell Setup.hs configure
3586 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3587 Instead of installing the package by running @code{runhaskell Setup.hs
3588 install}, to avoid trying to register libraries in the read-only
3589 compiler store directory, the build system uses @code{runhaskell
3590 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3591 addition, the build system generates the package documentation by
3592 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3593 is passed. Optional Haddock parameters can be passed with the help of
3594 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3595 not found, the build system looks for @code{Setup.lhs} instead.
3597 Which Haskell compiler is used can be specified with the @code{#:haskell}
3598 parameter which defaults to @code{ghc}.
3601 @defvr {Scheme Variable} dub-build-system
3602 This variable is exported by @code{(guix build-system dub)}. It
3603 implements the Dub build procedure used by D packages, which
3604 involves running @code{dub build} and @code{dub run}.
3605 Installation is done by copying the files manually.
3607 Which D compiler is used can be specified with the @code{#:ldc}
3608 parameter which defaults to @code{ldc}.
3611 @defvr {Scheme Variable} emacs-build-system
3612 This variable is exported by @code{(guix build-system emacs)}. It
3613 implements an installation procedure similar to the packaging system
3614 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3616 It first creates the @code{@var{package}-autoloads.el} file, then it
3617 byte compiles all Emacs Lisp files. Differently from the Emacs
3618 packaging system, the Info documentation files are moved to the standard
3619 documentation directory and the @file{dir} file is deleted. Each
3620 package is installed in its own directory under
3621 @file{share/emacs/site-lisp/guix.d}.
3624 Lastly, for packages that do not need anything as sophisticated, a
3625 ``trivial'' build system is provided. It is trivial in the sense that
3626 it provides basically no support: it does not pull any implicit inputs,
3627 and does not have a notion of build phases.
3629 @defvr {Scheme Variable} trivial-build-system
3630 This variable is exported by @code{(guix build-system trivial)}.
3632 This build system requires a @code{#:builder} argument. This argument
3633 must be a Scheme expression that builds the package output(s)---as
3634 with @code{build-expression->derivation} (@pxref{Derivations,
3635 @code{build-expression->derivation}}).
3645 Conceptually, the @dfn{store} is the place where derivations that have
3646 been built successfully are stored---by default, @file{/gnu/store}.
3647 Sub-directories in the store are referred to as @dfn{store items} or
3648 sometimes @dfn{store paths}. The store has an associated database that
3649 contains information such as the store paths referred to by each store
3650 path, and the list of @emph{valid} store items---results of successful
3651 builds. This database resides in @file{@var{localstatedir}/guix/db},
3652 where @var{localstatedir} is the state directory specified @i{via}
3653 @option{--localstatedir} at configure time, usually @file{/var}.
3655 The store is @emph{always} accessed by the daemon on behalf of its clients
3656 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3657 connect to the daemon over a Unix-domain socket, send requests to it,
3658 and read the result---these are remote procedure calls, or RPCs.
3661 Users must @emph{never} modify files under @file{/gnu/store} directly.
3662 This would lead to inconsistencies and break the immutability
3663 assumptions of Guix's functional model (@pxref{Introduction}).
3665 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3666 how to check the integrity of the store and attempt recovery from
3667 accidental modifications.
3670 The @code{(guix store)} module provides procedures to connect to the
3671 daemon, and to perform RPCs. These are described below. By default,
3672 @code{open-connection}, and thus all the @command{guix} commands,
3673 connect to the local daemon or to the URI specified by the
3674 @code{GUIX_DAEMON_SOCKET} environment variable.
3676 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3677 When set, the value of this variable should be a file name or a URI
3678 designating the daemon endpoint. When it is a file name, it denotes a
3679 Unix-domain socket to connect to. In addition to file names, the
3680 supported URI schemes are:
3685 These are for Unix-domain sockets.
3686 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3687 @file{/var/guix/daemon-socket/socket}.
3690 These URIs denote connections over TCP/IP, without encryption nor
3691 authentication of the remote host. The URI must always specify both the
3692 host name and port number:
3695 guix://master.guix.example.org:1234
3698 This setup is suitable on local networks, such as clusters, where only
3699 trusted nodes may connect to the build daemon at
3700 @code{master.guix.example.org}.
3703 @cindex SSH access to build daemons
3704 These URIs allow you to connect to a remote daemon over
3705 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3706 A typical URL might look like this:
3709 ssh://charlie@@guix.example.org:22
3712 As for @command{guix copy}, the usual OpenSSH client configuration files
3713 are honored (@pxref{Invoking guix copy}).
3716 Additional URI schemes may be supported in the future.
3718 @c XXX: Remove this note when the protocol incurs fewer round trips
3719 @c and when (guix derivations) no longer relies on file system access.
3721 The ability to connect to remote build daemons is considered
3722 experimental as of @value{VERSION}. Please get in touch with us to
3723 share any problems or suggestions you may have (@pxref{Contributing}).
3727 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3728 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3729 @var{reserve-space?} is true, instruct it to reserve a little bit of
3730 extra space on the file system so that the garbage collector can still
3731 operate should the disk become full. Return a server object.
3733 @var{file} defaults to @var{%default-socket-path}, which is the normal
3734 location given the options that were passed to @command{configure}.
3737 @deffn {Scheme Procedure} close-connection @var{server}
3738 Close the connection to @var{server}.
3741 @defvr {Scheme Variable} current-build-output-port
3742 This variable is bound to a SRFI-39 parameter, which refers to the port
3743 where build and error logs sent by the daemon should be written.
3746 Procedures that make RPCs all take a server object as their first
3749 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3750 @cindex invalid store items
3751 Return @code{#t} when @var{path} designates a valid store item and
3752 @code{#f} otherwise (an invalid item may exist on disk but still be
3753 invalid, for instance because it is the result of an aborted or failed
3756 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3757 prefixed by the store directory (@file{/gnu/store}).
3760 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3761 Add @var{text} under file @var{name} in the store, and return its store
3762 path. @var{references} is the list of store paths referred to by the
3763 resulting store path.
3766 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3767 Build @var{derivations} (a list of @code{<derivation>} objects or
3768 derivation paths), and return when the worker is done building them.
3769 Return @code{#t} on success.
3772 Note that the @code{(guix monads)} module provides a monad as well as
3773 monadic versions of the above procedures, with the goal of making it
3774 more convenient to work with code that accesses the store (@pxref{The
3778 @i{This section is currently incomplete.}
3781 @section Derivations
3784 Low-level build actions and the environment in which they are performed
3785 are represented by @dfn{derivations}. A derivation contains the
3786 following pieces of information:
3790 The outputs of the derivation---derivations produce at least one file or
3791 directory in the store, but may produce more.
3794 The inputs of the derivations, which may be other derivations or plain
3795 files in the store (patches, build scripts, etc.)
3798 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3801 The file name of a build script in the store, along with the arguments
3805 A list of environment variables to be defined.
3809 @cindex derivation path
3810 Derivations allow clients of the daemon to communicate build actions to
3811 the store. They exist in two forms: as an in-memory representation,
3812 both on the client- and daemon-side, and as files in the store whose
3813 name end in @code{.drv}---these files are referred to as @dfn{derivation
3814 paths}. Derivations paths can be passed to the @code{build-derivations}
3815 procedure to perform the build actions they prescribe (@pxref{The
3818 The @code{(guix derivations)} module provides a representation of
3819 derivations as Scheme objects, along with procedures to create and
3820 otherwise manipulate derivations. The lowest-level primitive to create
3821 a derivation is the @code{derivation} procedure:
3823 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3824 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3825 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3826 [#:system (%current-system)] [#:references-graphs #f] @
3827 [#:allowed-references #f] [#:disallowed-references #f] @
3828 [#:leaked-env-vars #f] [#:local-build? #f] @
3829 [#:substitutable? #t]
3830 Build a derivation with the given arguments, and return the resulting
3831 @code{<derivation>} object.
3833 When @var{hash} and @var{hash-algo} are given, a
3834 @dfn{fixed-output derivation} is created---i.e., one whose result is
3835 known in advance, such as a file download. If, in addition,
3836 @var{recursive?} is true, then that fixed output may be an executable
3837 file or a directory and @var{hash} must be the hash of an archive
3838 containing this output.
3840 When @var{references-graphs} is true, it must be a list of file
3841 name/store path pairs. In that case, the reference graph of each store
3842 path is exported in the build environment in the corresponding file, in
3843 a simple text format.
3845 When @var{allowed-references} is true, it must be a list of store items
3846 or outputs that the derivation's output may refer to. Likewise,
3847 @var{disallowed-references}, if true, must be a list of things the
3848 outputs may @emph{not} refer to.
3850 When @var{leaked-env-vars} is true, it must be a list of strings
3851 denoting environment variables that are allowed to ``leak'' from the
3852 daemon's environment to the build environment. This is only applicable
3853 to fixed-output derivations---i.e., when @var{hash} is true. The main
3854 use is to allow variables such as @code{http_proxy} to be passed to
3855 derivations that download files.
3857 When @var{local-build?} is true, declare that the derivation is not a
3858 good candidate for offloading and should rather be built locally
3859 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3860 where the costs of data transfers would outweigh the benefits.
3862 When @var{substitutable?} is false, declare that substitutes of the
3863 derivation's output should not be used (@pxref{Substitutes}). This is
3864 useful, for instance, when building packages that capture details of the
3865 host CPU instruction set.
3869 Here's an example with a shell script as its builder, assuming
3870 @var{store} is an open connection to the daemon, and @var{bash} points
3871 to a Bash executable in the store:
3874 (use-modules (guix utils)
3878 (let ((builder ; add the Bash script to the store
3879 (add-text-to-store store "my-builder.sh"
3880 "echo hello world > $out\n" '())))
3881 (derivation store "foo"
3882 bash `("-e" ,builder)
3883 #:inputs `((,bash) (,builder))
3884 #:env-vars '(("HOME" . "/homeless"))))
3885 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3888 As can be guessed, this primitive is cumbersome to use directly. A
3889 better approach is to write build scripts in Scheme, of course! The
3890 best course of action for that is to write the build code as a
3891 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3892 information, @pxref{G-Expressions}.
3894 Once upon a time, @code{gexp->derivation} did not exist and constructing
3895 derivations with build code written in Scheme was achieved with
3896 @code{build-expression->derivation}, documented below. This procedure
3897 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3899 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3900 @var{name} @var{exp} @
3901 [#:system (%current-system)] [#:inputs '()] @
3902 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3903 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3904 [#:references-graphs #f] [#:allowed-references #f] @
3905 [#:disallowed-references #f] @
3906 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3907 Return a derivation that executes Scheme expression @var{exp} as a
3908 builder for derivation @var{name}. @var{inputs} must be a list of
3909 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3910 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3911 modules from the current search path to be copied in the store,
3912 compiled, and made available in the load path during the execution of
3913 @var{exp}---e.g., @code{((guix build utils) (guix build
3914 gnu-build-system))}.
3916 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3917 to a list of output/path pairs, and where @code{%build-inputs} is bound
3918 to a list of string/output-path pairs made from @var{inputs}.
3919 Optionally, @var{env-vars} is a list of string pairs specifying the name
3920 and value of environment variables visible to the builder. The builder
3921 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3922 @var{exp} returns @code{#f}, the build is considered to have failed.
3924 @var{exp} is built using @var{guile-for-build} (a derivation). When
3925 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3926 @code{%guile-for-build} fluid is used instead.
3928 See the @code{derivation} procedure for the meaning of
3929 @var{references-graphs}, @var{allowed-references},
3930 @var{disallowed-references}, @var{local-build?}, and
3931 @var{substitutable?}.
3935 Here's an example of a single-output derivation that creates a directory
3936 containing one file:
3939 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3940 (mkdir out) ; create /gnu/store/@dots{}-goo
3941 (call-with-output-file (string-append out "/test")
3943 (display '(hello guix) p))))))
3944 (build-expression->derivation store "goo" builder))
3946 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3950 @node The Store Monad
3951 @section The Store Monad
3955 The procedures that operate on the store described in the previous
3956 sections all take an open connection to the build daemon as their first
3957 argument. Although the underlying model is functional, they either have
3958 side effects or depend on the current state of the store.
3960 The former is inconvenient: the connection to the build daemon has to be
3961 carried around in all those functions, making it impossible to compose
3962 functions that do not take that parameter with functions that do. The
3963 latter can be problematic: since store operations have side effects
3964 and/or depend on external state, they have to be properly sequenced.
3966 @cindex monadic values
3967 @cindex monadic functions
3968 This is where the @code{(guix monads)} module comes in. This module
3969 provides a framework for working with @dfn{monads}, and a particularly
3970 useful monad for our uses, the @dfn{store monad}. Monads are a
3971 construct that allows two things: associating ``context'' with values
3972 (in our case, the context is the store), and building sequences of
3973 computations (here computations include accesses to the store). Values
3974 in a monad---values that carry this additional context---are called
3975 @dfn{monadic values}; procedures that return such values are called
3976 @dfn{monadic procedures}.
3978 Consider this ``normal'' procedure:
3981 (define (sh-symlink store)
3982 ;; Return a derivation that symlinks the 'bash' executable.
3983 (let* ((drv (package-derivation store bash))
3984 (out (derivation->output-path drv))
3985 (sh (string-append out "/bin/bash")))
3986 (build-expression->derivation store "sh"
3987 `(symlink ,sh %output))))
3990 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3991 as a monadic function:
3994 (define (sh-symlink)
3995 ;; Same, but return a monadic value.
3996 (mlet %store-monad ((drv (package->derivation bash)))
3997 (gexp->derivation "sh"
3998 #~(symlink (string-append #$drv "/bin/bash")
4002 There are several things to note in the second version: the @code{store}
4003 parameter is now implicit and is ``threaded'' in the calls to the
4004 @code{package->derivation} and @code{gexp->derivation} monadic
4005 procedures, and the monadic value returned by @code{package->derivation}
4006 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4008 As it turns out, the call to @code{package->derivation} can even be
4009 omitted since it will take place implicitly, as we will see later
4010 (@pxref{G-Expressions}):
4013 (define (sh-symlink)
4014 (gexp->derivation "sh"
4015 #~(symlink (string-append #$bash "/bin/bash")
4020 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4021 @c for the funny quote.
4022 Calling the monadic @code{sh-symlink} has no effect. As someone once
4023 said, ``you exit a monad like you exit a building on fire: by running''.
4024 So, to exit the monad and get the desired effect, one must use
4025 @code{run-with-store}:
4028 (run-with-store (open-connection) (sh-symlink))
4029 @result{} /gnu/store/...-sh-symlink
4032 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4033 new ``meta-commands'' to make it easier to deal with monadic procedures:
4034 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4035 to ``run'' a single monadic value through the store:
4038 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4039 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4042 The latter enters a recursive REPL, where all the return values are
4043 automatically run through the store:
4046 scheme@@(guile-user)> ,enter-store-monad
4047 store-monad@@(guile-user) [1]> (package->derivation hello)
4048 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4049 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4050 $3 = "/gnu/store/@dots{}-foo"
4051 store-monad@@(guile-user) [1]> ,q
4052 scheme@@(guile-user)>
4056 Note that non-monadic values cannot be returned in the
4057 @code{store-monad} REPL.
4059 The main syntactic forms to deal with monads in general are provided by
4060 the @code{(guix monads)} module and are described below.
4062 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4063 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4067 @deffn {Scheme Syntax} return @var{val}
4068 Return a monadic value that encapsulates @var{val}.
4071 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4072 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4073 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4074 referred to as ``bind'', but that name denotes an unrelated procedure in
4075 Guile. Thus we use this somewhat cryptic symbol inherited from the
4076 Haskell language.}. There can be one @var{mproc} or several of them, as
4081 (with-monad %state-monad
4083 (lambda (x) (return (+ 1 x)))
4084 (lambda (x) (return (* 2 x)))))
4088 @result{} some-state
4092 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4094 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4096 Bind the variables @var{var} to the monadic values @var{mval} in
4097 @var{body}, which is a sequence of expressions. As with the bind
4098 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4099 value ``contained'' in @var{mval} and making @var{var} refer to that
4100 raw, non-monadic value within the scope of the @var{body}. The form
4101 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4102 @var{val}, as per @code{let}. The binding operations occur in sequence
4103 from left to right. The last expression of @var{body} must be a monadic
4104 expression, and its result will become the result of the @code{mlet} or
4105 @code{mlet*} when run in the @var{monad}.
4107 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4108 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4111 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4112 Bind @var{mexp} and the following monadic expressions in sequence,
4113 returning the result of the last expression. Every expression in the
4114 sequence must be a monadic expression.
4116 This is akin to @code{mlet}, except that the return values of the
4117 monadic expressions are ignored. In that sense, it is analogous to
4118 @code{begin}, but applied to monadic expressions.
4121 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4122 When @var{condition} is true, evaluate the sequence of monadic
4123 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4124 @var{condition} is false, return @code{*unspecified*} in the current
4125 monad. Every expression in the sequence must be a monadic expression.
4128 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4129 When @var{condition} is false, evaluate the sequence of monadic
4130 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4131 @var{condition} is true, return @code{*unspecified*} in the current
4132 monad. Every expression in the sequence must be a monadic expression.
4136 The @code{(guix monads)} module provides the @dfn{state monad}, which
4137 allows an additional value---the state---to be @emph{threaded} through
4138 monadic procedure calls.
4140 @defvr {Scheme Variable} %state-monad
4141 The state monad. Procedures in the state monad can access and change
4142 the state that is threaded.
4144 Consider the example below. The @code{square} procedure returns a value
4145 in the state monad. It returns the square of its argument, but also
4146 increments the current state value:
4150 (mlet %state-monad ((count (current-state)))
4151 (mbegin %state-monad
4152 (set-current-state (+ 1 count))
4155 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4160 When ``run'' through @var{%state-monad}, we obtain that additional state
4161 value, which is the number of @code{square} calls.
4164 @deffn {Monadic Procedure} current-state
4165 Return the current state as a monadic value.
4168 @deffn {Monadic Procedure} set-current-state @var{value}
4169 Set the current state to @var{value} and return the previous state as a
4173 @deffn {Monadic Procedure} state-push @var{value}
4174 Push @var{value} to the current state, which is assumed to be a list,
4175 and return the previous state as a monadic value.
4178 @deffn {Monadic Procedure} state-pop
4179 Pop a value from the current state and return it as a monadic value.
4180 The state is assumed to be a list.
4183 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4184 Run monadic value @var{mval} starting with @var{state} as the initial
4185 state. Return two values: the resulting value, and the resulting state.
4188 The main interface to the store monad, provided by the @code{(guix
4189 store)} module, is as follows.
4191 @defvr {Scheme Variable} %store-monad
4192 The store monad---an alias for @var{%state-monad}.
4194 Values in the store monad encapsulate accesses to the store. When its
4195 effect is needed, a value of the store monad must be ``evaluated'' by
4196 passing it to the @code{run-with-store} procedure (see below.)
4199 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4200 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4201 open store connection.
4204 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4205 Return as a monadic value the absolute file name in the store of the file
4206 containing @var{text}, a string. @var{references} is a list of store items that the
4207 resulting text file refers to; it defaults to the empty list.
4210 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4211 [#:recursive? #t] [#:select? (const #t)]
4212 Return the name of @var{file} once interned in the store. Use
4213 @var{name} as its store name, or the basename of @var{file} if
4214 @var{name} is omitted.
4216 When @var{recursive?} is true, the contents of @var{file} are added
4217 recursively; if @var{file} designates a flat file and @var{recursive?}
4218 is true, its contents are added, and its permission bits are kept.
4220 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4221 @var{stat})} for each directory entry, where @var{file} is the entry's
4222 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4223 entries for which @var{select?} does not return true.
4225 The example below adds a file to the store, under two different names:
4228 (run-with-store (open-connection)
4229 (mlet %store-monad ((a (interned-file "README"))
4230 (b (interned-file "README" "LEGU-MIN")))
4231 (return (list a b))))
4233 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4238 The @code{(guix packages)} module exports the following package-related
4241 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4242 [#:system (%current-system)] [#:target #f] @
4245 value in the absolute file name of @var{file} within the @var{output}
4246 directory of @var{package}. When @var{file} is omitted, return the name
4247 of the @var{output} directory of @var{package}. When @var{target} is
4248 true, use it as a cross-compilation target triplet.
4251 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4252 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4253 @var{target} [@var{system}]
4254 Monadic version of @code{package-derivation} and
4255 @code{package-cross-derivation} (@pxref{Defining Packages}).
4260 @section G-Expressions
4262 @cindex G-expression
4263 @cindex build code quoting
4264 So we have ``derivations'', which represent a sequence of build actions
4265 to be performed to produce an item in the store (@pxref{Derivations}).
4266 These build actions are performed when asking the daemon to actually
4267 build the derivations; they are run by the daemon in a container
4268 (@pxref{Invoking guix-daemon}).
4270 @cindex strata of code
4271 It should come as no surprise that we like to write these build actions
4272 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4273 code@footnote{The term @dfn{stratum} in this context was coined by
4274 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4275 Kiselyov, who has written insightful
4276 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4277 on this topic}, refers to this kind of code generation as
4278 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4279 to the daemon, etc.---and the ``build code''---code that actually
4280 performs build actions, such as making directories, invoking
4281 @command{make}, etc.
4283 To describe a derivation and its build actions, one typically needs to
4284 embed build code inside host code. It boils down to manipulating build
4285 code as data, and the homoiconicity of Scheme---code has a direct
4286 representation as data---comes in handy for that. But we need more than
4287 the normal @code{quasiquote} mechanism in Scheme to construct build
4290 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4291 S-expressions adapted to build expressions. G-expressions, or
4292 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4293 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4294 @code{#$}, and @code{#$@@}), which are comparable to
4295 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4296 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4297 GNU Guile Reference Manual}). However, there are major differences:
4301 Gexps are meant to be written to a file and run or manipulated by other
4305 When a high-level object such as a package or derivation is unquoted
4306 inside a gexp, the result is as if its output file name had been
4310 Gexps carry information about the packages or derivations they refer to,
4311 and these dependencies are automatically added as inputs to the build
4312 processes that use them.
4315 @cindex lowering, of high-level objects in gexps
4316 This mechanism is not limited to package and derivation
4317 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4318 derivations or files in the store can be defined,
4319 such that these objects can also be inserted
4320 into gexps. For example, a useful type of high-level objects that can be
4321 inserted in a gexp is ``file-like objects'', which make it easy to
4322 add files to the store and to refer to them in
4323 derivations and such (see @code{local-file} and @code{plain-file}
4326 To illustrate the idea, here is an example of a gexp:
4333 (symlink (string-append #$coreutils "/bin/ls")
4337 This gexp can be passed to @code{gexp->derivation}; we obtain a
4338 derivation that builds a directory containing exactly one symlink to
4339 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4342 (gexp->derivation "the-thing" build-exp)
4345 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4346 substituted to the reference to the @var{coreutils} package in the
4347 actual build code, and @var{coreutils} is automatically made an input to
4348 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4349 output)}) is replaced by a string containing the directory name of the
4350 output of the derivation.
4352 @cindex cross compilation
4353 In a cross-compilation context, it is useful to distinguish between
4354 references to the @emph{native} build of a package---that can run on the
4355 host---versus references to cross builds of a package. To that end, the
4356 @code{#+} plays the same role as @code{#$}, but is a reference to a
4357 native package build:
4360 (gexp->derivation "vi"
4363 (system* (string-append #+coreutils "/bin/ln")
4365 (string-append #$emacs "/bin/emacs")
4366 (string-append #$output "/bin/vi")))
4367 #:target "mips64el-linux-gnu")
4371 In the example above, the native build of @var{coreutils} is used, so
4372 that @command{ln} can actually run on the host; but then the
4373 cross-compiled build of @var{emacs} is referenced.
4375 @cindex imported modules, for gexps
4376 @findex with-imported-modules
4377 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4378 able to use certain Guile modules from the ``host environment'' in the
4379 gexp, so those modules should be imported in the ``build environment''.
4380 The @code{with-imported-modules} form allows you to express that:
4383 (let ((build (with-imported-modules '((guix build utils))
4385 (use-modules (guix build utils))
4386 (mkdir-p (string-append #$output "/bin"))))))
4387 (gexp->derivation "empty-dir"
4390 (display "success!\n")
4395 In this example, the @code{(guix build utils)} module is automatically
4396 pulled into the isolated build environment of our gexp, such that
4397 @code{(use-modules (guix build utils))} works as expected.
4399 @cindex module closure
4400 @findex source-module-closure
4401 Usually you want the @emph{closure} of the module to be imported---i.e.,
4402 the module itself and all the modules it depends on---rather than just
4403 the module; failing to do that, attempts to use the module will fail
4404 because of missing dependent modules. The @code{source-module-closure}
4405 procedure computes the closure of a module by looking at its source file
4406 headers, which comes in handy in this case:
4409 (use-modules (guix modules)) ;for 'source-module-closure'
4411 (with-imported-modules (source-module-closure
4412 '((guix build utils)
4414 (gexp->derivation "something-with-vms"
4416 (use-modules (guix build utils)
4421 The syntactic form to construct gexps is summarized below.
4423 @deffn {Scheme Syntax} #~@var{exp}
4424 @deffnx {Scheme Syntax} (gexp @var{exp})
4425 Return a G-expression containing @var{exp}. @var{exp} may contain one
4426 or more of the following forms:
4430 @itemx (ungexp @var{obj})
4431 Introduce a reference to @var{obj}. @var{obj} may have one of the
4432 supported types, for example a package or a
4433 derivation, in which case the @code{ungexp} form is replaced by its
4434 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4436 If @var{obj} is a list, it is traversed and references to supported
4437 objects are substituted similarly.
4439 If @var{obj} is another gexp, its contents are inserted and its
4440 dependencies are added to those of the containing gexp.
4442 If @var{obj} is another kind of object, it is inserted as is.
4444 @item #$@var{obj}:@var{output}
4445 @itemx (ungexp @var{obj} @var{output})
4446 This is like the form above, but referring explicitly to the
4447 @var{output} of @var{obj}---this is useful when @var{obj} produces
4448 multiple outputs (@pxref{Packages with Multiple Outputs}).
4451 @itemx #+@var{obj}:output
4452 @itemx (ungexp-native @var{obj})
4453 @itemx (ungexp-native @var{obj} @var{output})
4454 Same as @code{ungexp}, but produces a reference to the @emph{native}
4455 build of @var{obj} when used in a cross compilation context.
4457 @item #$output[:@var{output}]
4458 @itemx (ungexp output [@var{output}])
4459 Insert a reference to derivation output @var{output}, or to the main
4460 output when @var{output} is omitted.
4462 This only makes sense for gexps passed to @code{gexp->derivation}.
4465 @itemx (ungexp-splicing @var{lst})
4466 Like the above, but splices the contents of @var{lst} inside the
4470 @itemx (ungexp-native-splicing @var{lst})
4471 Like the above, but refers to native builds of the objects listed in
4476 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4477 of the @code{gexp?} type (see below.)
4480 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4481 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4482 in their execution environment.
4484 Each item in @var{modules} can be the name of a module, such as
4485 @code{(guix build utils)}, or it can be a module name, followed by an
4486 arrow, followed by a file-like object:
4489 `((guix build utils)
4491 ((guix config) => ,(scheme-file "config.scm"
4492 #~(define-module @dots{}))))
4496 In the example above, the first two modules are taken from the search
4497 path, and the last one is created from the given file-like object.
4499 This form has @emph{lexical} scope: it has an effect on the gexps
4500 directly defined in @var{body}@dots{}, but not on those defined, say, in
4501 procedures called from @var{body}@dots{}.
4504 @deffn {Scheme Procedure} gexp? @var{obj}
4505 Return @code{#t} if @var{obj} is a G-expression.
4508 G-expressions are meant to be written to disk, either as code building
4509 some derivation, or as plain files in the store. The monadic procedures
4510 below allow you to do that (@pxref{The Store Monad}, for more
4511 information about monads.)
4513 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4514 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4515 [#:hash #f] [#:hash-algo #f] @
4516 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4517 [#:module-path @var{%load-path}] @
4518 [#:references-graphs #f] [#:allowed-references #f] @
4519 [#:disallowed-references #f] @
4520 [#:leaked-env-vars #f] @
4521 [#:script-name (string-append @var{name} "-builder")] @
4522 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4523 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4524 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4525 stored in a file called @var{script-name}. When @var{target} is true,
4526 it is used as the cross-compilation target triplet for packages referred
4529 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4531 make @var{modules} available in the evaluation context of @var{exp};
4532 @var{modules} is a list of names of Guile modules searched in
4533 @var{module-path} to be copied in the store, compiled, and made available in
4534 the load path during the execution of @var{exp}---e.g., @code{((guix
4535 build utils) (guix build gnu-build-system))}.
4537 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4540 When @var{references-graphs} is true, it must be a list of tuples of one of the
4544 (@var{file-name} @var{package})
4545 (@var{file-name} @var{package} @var{output})
4546 (@var{file-name} @var{derivation})
4547 (@var{file-name} @var{derivation} @var{output})
4548 (@var{file-name} @var{store-item})
4551 The right-hand-side of each element of @var{references-graphs} is automatically made
4552 an input of the build process of @var{exp}. In the build environment, each
4553 @var{file-name} contains the reference graph of the corresponding item, in a simple
4556 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4557 In the latter case, the list denotes store items that the result is allowed to
4558 refer to. Any reference to another store item will lead to a build error.
4559 Similarly for @var{disallowed-references}, which can list items that must not be
4560 referenced by the outputs.
4562 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4565 @cindex file-like objects
4566 The @code{local-file}, @code{plain-file}, @code{computed-file},
4567 @code{program-file}, and @code{scheme-file} procedures below return
4568 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4569 these objects lead to a file in the store. Consider this G-expression:
4572 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4573 #$(local-file "/tmp/my-nscd.conf"))
4576 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4577 to the store. Once expanded, for instance @i{via}
4578 @code{gexp->derivation}, the G-expression refers to that copy under
4579 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4580 does not have any effect on what the G-expression does.
4581 @code{plain-file} can be used similarly; it differs in that the file
4582 content is directly passed as a string.
4584 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4585 [#:recursive? #f] [#:select? (const #t)]
4586 Return an object representing local file @var{file} to add to the store; this
4587 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4588 up relative to the source file where this form appears. @var{file} will be added to
4589 the store under @var{name}--by default the base name of @var{file}.
4591 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4592 designates a flat file and @var{recursive?} is true, its contents are added, and its
4593 permission bits are kept.
4595 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4596 @var{stat})} for each directory entry, where @var{file} is the entry's
4597 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4598 entries for which @var{select?} does not return true.
4600 This is the declarative counterpart of the @code{interned-file} monadic
4601 procedure (@pxref{The Store Monad, @code{interned-file}}).
4604 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4605 Return an object representing a text file called @var{name} with the given
4606 @var{content} (a string) to be added to the store.
4608 This is the declarative counterpart of @code{text-file}.
4611 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4612 [#:options '(#:local-build? #t)]
4613 Return an object representing the store item @var{name}, a file or
4614 directory computed by @var{gexp}. @var{options}
4615 is a list of additional arguments to pass to @code{gexp->derivation}.
4617 This is the declarative counterpart of @code{gexp->derivation}.
4620 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4621 Return an executable script @var{name} that runs @var{exp} using
4622 @var{guile}, with @var{exp}'s imported modules in its search path.
4624 The example below builds a script that simply invokes the @command{ls}
4628 (use-modules (guix gexp) (gnu packages base))
4630 (gexp->script "list-files"
4631 #~(execl #$(file-append coreutils "/bin/ls")
4635 When ``running'' it through the store (@pxref{The Store Monad,
4636 @code{run-with-store}}), we obtain a derivation that produces an
4637 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4640 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4642 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4646 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4648 Return an object representing the executable store item @var{name} that
4649 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4652 This is the declarative counterpart of @code{gexp->script}.
4655 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4656 [#:set-load-path? #t]
4657 Return a derivation that builds a file @var{name} containing @var{exp}.
4658 When @var{set-load-path?} is true, emit code in the resulting file to
4659 set @code{%load-path} and @code{%load-compiled-path} to honor
4660 @var{exp}'s imported modules.
4662 The resulting file holds references to all the dependencies of @var{exp}
4663 or a subset thereof.
4666 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4667 Return an object representing the Scheme file @var{name} that contains
4670 This is the declarative counterpart of @code{gexp->file}.
4673 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4674 Return as a monadic value a derivation that builds a text file
4675 containing all of @var{text}. @var{text} may list, in addition to
4676 strings, objects of any type that can be used in a gexp: packages,
4677 derivations, local file objects, etc. The resulting store file holds
4678 references to all these.
4680 This variant should be preferred over @code{text-file} anytime the file
4681 to create will reference items from the store. This is typically the
4682 case when building a configuration file that embeds store file names,
4686 (define (profile.sh)
4687 ;; Return the name of a shell script in the store that
4688 ;; initializes the 'PATH' environment variable.
4689 (text-file* "profile.sh"
4690 "export PATH=" coreutils "/bin:"
4691 grep "/bin:" sed "/bin\n"))
4694 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4695 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4696 preventing them from being garbage-collected during its lifetime.
4699 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4700 Return an object representing store file @var{name} containing
4701 @var{text}. @var{text} is a sequence of strings and file-like objects,
4705 (mixed-text-file "profile"
4706 "export PATH=" coreutils "/bin:" grep "/bin")
4709 This is the declarative counterpart of @code{text-file*}.
4712 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4713 Return a file-like object that expands to the concatenation of @var{obj}
4714 and @var{suffix}, where @var{obj} is a lowerable object and each
4715 @var{suffix} is a string.
4717 As an example, consider this gexp:
4720 (gexp->script "run-uname"
4721 #~(system* #$(file-append coreutils
4725 The same effect could be achieved with:
4728 (gexp->script "run-uname"
4729 #~(system* (string-append #$coreutils
4733 There is one difference though: in the @code{file-append} case, the
4734 resulting script contains the absolute file name as a string, whereas in
4735 the second case, the resulting script contains a @code{(string-append
4736 @dots{})} expression to construct the file name @emph{at run time}.
4740 Of course, in addition to gexps embedded in ``host'' code, there are
4741 also modules containing build tools. To make it clear that they are
4742 meant to be used in the build stratum, these modules are kept in the
4743 @code{(guix build @dots{})} name space.
4745 @cindex lowering, of high-level objects in gexps
4746 Internally, high-level objects are @dfn{lowered}, using their compiler,
4747 to either derivations or store items. For instance, lowering a package
4748 yields a derivation, and lowering a @code{plain-file} yields a store
4749 item. This is achieved using the @code{lower-object} monadic procedure.
4751 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4753 Return as a value in @var{%store-monad} the derivation or store item
4754 corresponding to @var{obj} for @var{system}, cross-compiling for
4755 @var{target} if @var{target} is true. @var{obj} must be an object that
4756 has an associated gexp compiler, such as a @code{<package>}.
4760 @c *********************************************************************
4764 This section describes Guix command-line utilities. Some of them are
4765 primarily targeted at developers and users who write new package
4766 definitions, while others are more generally useful. They complement
4767 the Scheme programming interface of Guix in a convenient way.
4770 * Invoking guix build:: Building packages from the command line.
4771 * Invoking guix edit:: Editing package definitions.
4772 * Invoking guix download:: Downloading a file and printing its hash.
4773 * Invoking guix hash:: Computing the cryptographic hash of a file.
4774 * Invoking guix import:: Importing package definitions.
4775 * Invoking guix refresh:: Updating package definitions.
4776 * Invoking guix lint:: Finding errors in package definitions.
4777 * Invoking guix size:: Profiling disk usage.
4778 * Invoking guix graph:: Visualizing the graph of packages.
4779 * Invoking guix environment:: Setting up development environments.
4780 * Invoking guix publish:: Sharing substitutes.
4781 * Invoking guix challenge:: Challenging substitute servers.
4782 * Invoking guix copy:: Copying to and from a remote store.
4783 * Invoking guix container:: Process isolation.
4786 @node Invoking guix build
4787 @section Invoking @command{guix build}
4789 @cindex package building
4790 @cindex @command{guix build}
4791 The @command{guix build} command builds packages or derivations and
4792 their dependencies, and prints the resulting store paths. Note that it
4793 does not modify the user's profile---this is the job of the
4794 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4795 it is mainly useful for distribution developers.
4797 The general syntax is:
4800 guix build @var{options} @var{package-or-derivation}@dots{}
4803 As an example, the following command builds the latest versions of Emacs
4804 and of Guile, displays their build logs, and finally displays the
4805 resulting directories:
4808 guix build emacs guile
4811 Similarly, the following command builds all the available packages:
4814 guix build --quiet --keep-going \
4815 `guix package -A | cut -f1,2 --output-delimiter=@@`
4818 @var{package-or-derivation} may be either the name of a package found in
4819 the software distribution such as @code{coreutils} or
4820 @code{coreutils@@8.20}, or a derivation such as
4821 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4822 package with the corresponding name (and optionally version) is searched
4823 for among the GNU distribution modules (@pxref{Package Modules}).
4825 Alternatively, the @code{--expression} option may be used to specify a
4826 Scheme expression that evaluates to a package; this is useful when
4827 disambiguating among several same-named packages or package variants is
4830 There may be zero or more @var{options}. The available options are
4831 described in the subsections below.
4834 * Common Build Options:: Build options for most commands.
4835 * Package Transformation Options:: Creating variants of packages.
4836 * Additional Build Options:: Options specific to 'guix build'.
4837 * Debugging Build Failures:: Real life packaging experience
4840 @node Common Build Options
4841 @subsection Common Build Options
4843 A number of options that control the build process are common to
4844 @command{guix build} and other commands that can spawn builds, such as
4845 @command{guix package} or @command{guix archive}. These are the
4850 @item --load-path=@var{directory}
4851 @itemx -L @var{directory}
4852 Add @var{directory} to the front of the package module search path
4853 (@pxref{Package Modules}).
4855 This allows users to define their own packages and make them visible to
4856 the command-line tools.
4860 Keep the build tree of failed builds. Thus, if a build fails, its build
4861 tree is kept under @file{/tmp}, in a directory whose name is shown at
4862 the end of the build log. This is useful when debugging build issues.
4863 @xref{Debugging Build Failures}, for tips and tricks on how to debug
4868 Keep going when some of the derivations fail to build; return only once
4869 all the builds have either completed or failed.
4871 The default behavior is to stop as soon as one of the specified
4872 derivations has failed.
4876 Do not build the derivations.
4879 When substituting a pre-built binary fails, fall back to building
4882 @item --substitute-urls=@var{urls}
4883 @anchor{client-substitute-urls}
4884 Consider @var{urls} the whitespace-separated list of substitute source
4885 URLs, overriding the default list of URLs of @command{guix-daemon}
4886 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4888 This means that substitutes may be downloaded from @var{urls}, provided
4889 they are signed by a key authorized by the system administrator
4890 (@pxref{Substitutes}).
4892 When @var{urls} is the empty string, substitutes are effectively
4895 @item --no-substitutes
4896 Do not use substitutes for build products. That is, always build things
4897 locally instead of allowing downloads of pre-built binaries
4898 (@pxref{Substitutes}).
4901 Do not ``graft'' packages. In practice, this means that package updates
4902 available as grafts are not applied. @xref{Security Updates}, for more
4903 information on grafts.
4905 @item --rounds=@var{n}
4906 Build each derivation @var{n} times in a row, and raise an error if
4907 consecutive build results are not bit-for-bit identical.
4909 This is a useful way to detect non-deterministic builds processes.
4910 Non-deterministic build processes are a problem because they make it
4911 practically impossible for users to @emph{verify} whether third-party
4912 binaries are genuine. @xref{Invoking guix challenge}, for more.
4914 Note that, currently, the differing build results are not kept around,
4915 so you will have to manually investigate in case of an error---e.g., by
4916 stashing one of the build results with @code{guix archive --export}
4917 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4920 @item --no-build-hook
4921 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4922 (@pxref{Daemon Offload Setup}). That is, always build things locally
4923 instead of offloading builds to remote machines.
4925 @item --max-silent-time=@var{seconds}
4926 When the build or substitution process remains silent for more than
4927 @var{seconds}, terminate it and report a build failure.
4929 @item --timeout=@var{seconds}
4930 Likewise, when the build or substitution process lasts for more than
4931 @var{seconds}, terminate it and report a build failure.
4933 By default there is no timeout. This behavior can be restored with
4936 @item --verbosity=@var{level}
4937 Use the given verbosity level. @var{level} must be an integer between 0
4938 and 5; higher means more verbose output. Setting a level of 4 or more
4939 may be helpful when debugging setup issues with the build daemon.
4941 @item --cores=@var{n}
4943 Allow the use of up to @var{n} CPU cores for the build. The special
4944 value @code{0} means to use as many CPU cores as available.
4946 @item --max-jobs=@var{n}
4948 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4949 guix-daemon, @code{--max-jobs}}, for details about this option and the
4950 equivalent @command{guix-daemon} option.
4954 Behind the scenes, @command{guix build} is essentially an interface to
4955 the @code{package-derivation} procedure of the @code{(guix packages)}
4956 module, and to the @code{build-derivations} procedure of the @code{(guix
4957 derivations)} module.
4959 In addition to options explicitly passed on the command line,
4960 @command{guix build} and other @command{guix} commands that support
4961 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4963 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4964 Users can define this variable to a list of command line options that
4965 will automatically be used by @command{guix build} and other
4966 @command{guix} commands that can perform builds, as in the example
4970 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4973 These options are parsed independently, and the result is appended to
4974 the parsed command-line options.
4978 @node Package Transformation Options
4979 @subsection Package Transformation Options
4981 @cindex package variants
4982 Another set of command-line options supported by @command{guix build}
4983 and also @command{guix package} are @dfn{package transformation
4984 options}. These are options that make it possible to define @dfn{package
4985 variants}---for instance, packages built from different source code.
4986 This is a convenient way to create customized packages on the fly
4987 without having to type in the definitions of package variants
4988 (@pxref{Defining Packages}).
4992 @item --with-source=@var{source}
4993 Use @var{source} as the source of the corresponding package.
4994 @var{source} must be a file name or a URL, as for @command{guix
4995 download} (@pxref{Invoking guix download}).
4997 The ``corresponding package'' is taken to be the one specified on the
4998 command line the name of which matches the base of @var{source}---e.g.,
4999 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5000 package is @code{guile}. Likewise, the version string is inferred from
5001 @var{source}; in the previous example, it is @code{2.0.10}.
5003 This option allows users to try out versions of packages other than the
5004 one provided by the distribution. The example below downloads
5005 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5006 the @code{ed} package:
5009 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5012 As a developer, @code{--with-source} makes it easy to test release
5016 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5019 @dots{} or to build from a checkout in a pristine environment:
5022 $ git clone git://git.sv.gnu.org/guix.git
5023 $ guix build guix --with-source=./guix
5026 @item --with-input=@var{package}=@var{replacement}
5027 Replace dependency on @var{package} by a dependency on
5028 @var{replacement}. @var{package} must be a package name, and
5029 @var{replacement} must be a package specification such as @code{guile}
5030 or @code{guile@@1.8}.
5032 For instance, the following command builds Guix, but replaces its
5033 dependency on the current stable version of Guile with a dependency on
5034 the legacy version of Guile, @code{guile@@2.0}:
5037 guix build --with-input=guile=guile@@2.0 guix
5040 This is a recursive, deep replacement. So in this example, both
5041 @code{guix} and its dependency @code{guile-json} (which also depends on
5042 @code{guile}) get rebuilt against @code{guile@@2.0}.
5044 This is implemented using the @code{package-input-rewriting} Scheme
5045 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5047 @item --with-graft=@var{package}=@var{replacement}
5048 This is similar to @code{--with-input} but with an important difference:
5049 instead of rebuilding the whole dependency chain, @var{replacement} is
5050 built and then @dfn{grafted} onto the binaries that were initially
5051 referring to @var{package}. @xref{Security Updates}, for more
5052 information on grafts.
5054 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5055 and all its dependencies, replacing references to the version of GnuTLS
5056 they currently refer to:
5059 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5062 This has the advantage of being much faster than rebuilding everything.
5063 But there is a caveat: it works if and only if @var{package} and
5064 @var{replacement} are strictly compatible---for example, if they provide
5065 a library, the application binary interface (ABI) of those libraries
5066 must be compatible. If @var{replacement} is somehow incompatible with
5067 @var{package}, then the resulting package may be unusable. Use with
5072 @node Additional Build Options
5073 @subsection Additional Build Options
5075 The command-line options presented below are specific to @command{guix
5082 Build quietly, without displaying the build log. Upon completion, the
5083 build log is kept in @file{/var} (or similar) and can always be
5084 retrieved using the @option{--log-file} option.
5086 @item --file=@var{file}
5087 @itemx -f @var{file}
5089 Build the package or derivation that the code within @var{file}
5092 As an example, @var{file} might contain a package definition like this
5093 (@pxref{Defining Packages}):
5096 @verbatiminclude package-hello.scm
5099 @item --expression=@var{expr}
5100 @itemx -e @var{expr}
5101 Build the package or derivation @var{expr} evaluates to.
5103 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5104 guile-1.8)}, which unambiguously designates this specific variant of
5105 version 1.8 of Guile.
5107 Alternatively, @var{expr} may be a G-expression, in which case it is used
5108 as a build program passed to @code{gexp->derivation}
5109 (@pxref{G-Expressions}).
5111 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5112 (@pxref{The Store Monad}). The procedure must return a derivation as a
5113 monadic value, which is then passed through @code{run-with-store}.
5117 Build the source derivations of the packages, rather than the packages
5120 For instance, @code{guix build -S gcc} returns something like
5121 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5124 The returned source tarball is the result of applying any patches and
5125 code snippets specified in the package @code{origin} (@pxref{Defining
5129 Fetch and return the source of @var{package-or-derivation} and all their
5130 dependencies, recursively. This is a handy way to obtain a local copy
5131 of all the source code needed to build @var{packages}, allowing you to
5132 eventually build them even without network access. It is an extension
5133 of the @code{--source} option and can accept one of the following
5134 optional argument values:
5138 This value causes the @code{--sources} option to behave in the same way
5139 as the @code{--source} option.
5142 Build the source derivations of all packages, including any source that
5143 might be listed as @code{inputs}. This is the default value.
5146 $ guix build --sources tzdata
5147 The following derivations will be built:
5148 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5149 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5153 Build the source derivations of all packages, as well of all transitive
5154 inputs to the packages. This can be used e.g. to
5155 prefetch package source for later offline building.
5158 $ guix build --sources=transitive tzdata
5159 The following derivations will be built:
5160 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5161 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5162 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5163 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5164 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5165 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5171 @item --system=@var{system}
5172 @itemx -s @var{system}
5173 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5174 the system type of the build host.
5176 An example use of this is on Linux-based systems, which can emulate
5177 different personalities. For instance, passing
5178 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5179 to build packages in a complete 32-bit environment.
5181 @item --target=@var{triplet}
5182 @cindex cross-compilation
5183 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5184 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5185 configuration triplets,, autoconf, Autoconf}).
5187 @anchor{build-check}
5189 @cindex determinism, checking
5190 @cindex reproducibility, checking
5191 Rebuild @var{package-or-derivation}, which are already available in the
5192 store, and raise an error if the build results are not bit-for-bit
5195 This mechanism allows you to check whether previously installed
5196 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5197 of a package is deterministic. @xref{Invoking guix challenge}, for more
5198 background information and tools.
5200 When used in conjunction with @option{--keep-failed}, the differing
5201 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5202 This makes it easy to look for differences between the two results.
5205 @cindex repairing store items
5206 @cindex corruption, recovering from
5207 Attempt to repair the specified store items, if they are corrupt, by
5208 re-downloading or rebuilding them.
5210 This operation is not atomic and thus restricted to @code{root}.
5214 Return the derivation paths, not the output paths, of the given
5217 @item --root=@var{file}
5218 @itemx -r @var{file}
5219 Make @var{file} a symlink to the result, and register it as a garbage
5223 Return the build log file names or URLs for the given
5224 @var{package-or-derivation}, or raise an error if build logs are
5227 This works regardless of how packages or derivations are specified. For
5228 instance, the following invocations are equivalent:
5231 guix build --log-file `guix build -d guile`
5232 guix build --log-file `guix build guile`
5233 guix build --log-file guile
5234 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5237 If a log is unavailable locally, and unless @code{--no-substitutes} is
5238 passed, the command looks for a corresponding log on one of the
5239 substitute servers (as specified with @code{--substitute-urls}.)
5241 So for instance, imagine you want to see the build log of GDB on MIPS,
5242 but you are actually on an @code{x86_64} machine:
5245 $ guix build --log-file gdb -s mips64el-linux
5246 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5249 You can freely access a huge library of build logs!
5252 @node Debugging Build Failures
5253 @subsection Debugging Build Failures
5255 @cindex build failures, debugging
5256 When defining a new package (@pxref{Defining Packages}), you will
5257 probably find yourself spending some time debugging and tweaking the
5258 build until it succeeds. To do that, you need to operate the build
5259 commands yourself in an environment as close as possible to the one the
5262 To that end, the first thing to do is to use the @option{--keep-failed}
5263 or @option{-K} option of @command{guix build}, which will keep the
5264 failed build tree in @file{/tmp} or whatever directory you specified as
5265 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5267 From there on, you can @command{cd} to the failed build tree and source
5268 the @file{environment-variables} file, which contains all the
5269 environment variable definitions that were in place when the build
5270 failed. So let's say you're debugging a build failure in package
5271 @code{foo}; a typical session would look like this:
5275 @dots{} @i{build fails}
5276 $ cd /tmp/guix-build-foo.drv-0
5277 $ source ./environment-variables
5281 Now, you can invoke commands as if you were the daemon (almost) and
5282 troubleshoot your build process.
5284 Sometimes it happens that, for example, a package's tests pass when you
5285 run them manually but they fail when the daemon runs them. This can
5286 happen because the daemon runs builds in containers where, unlike in our
5287 environment above, network access is missing, @file{/bin/sh} does not
5288 exist, etc. (@pxref{Build Environment Setup}).
5290 In such cases, you may need to run inspect the build process from within
5291 a container similar to the one the build daemon creates:
5296 $ cd /tmp/guix-build-foo.drv-0
5297 $ guix environment -C foo --ad-hoc strace gdb
5298 [env]# source ./environment-variables
5302 Here, @command{guix environment -C} creates a container and spawns a new
5303 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5304 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5305 the container, which would may find handy while debugging.
5307 To get closer to a container like that used by the build daemon, we can
5308 remove @file{/bin/sh}:
5314 (Don't worry, this is harmless: this is all happening in the throw-away
5315 container created by @command{guix environment}.)
5317 The @command{strace} command is probably not in the search path, but we
5321 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5324 In this way, not only you will have reproduced the environment variables
5325 the daemon uses, you will also be running the build process in a container
5326 similar to the one the daemon uses.
5329 @node Invoking guix edit
5330 @section Invoking @command{guix edit}
5332 @cindex @command{guix edit}
5333 @cindex package definition, editing
5334 So many packages, so many source files! The @command{guix edit} command
5335 facilitates the life of users and packagers by pointing their editor at
5336 the source file containing the definition of the specified packages.
5340 guix edit gcc@@4.9 vim
5344 launches the program specified in the @code{VISUAL} or in the
5345 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5348 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5349 have created your own packages on @code{GUIX_PACKAGE_PATH}
5350 (@pxref{Defining Packages}), you will be able to edit the package
5351 recipes. Otherwise, you will be able to examine the read-only recipes
5352 for packages currently in the store.
5355 @node Invoking guix download
5356 @section Invoking @command{guix download}
5358 @cindex @command{guix download}
5359 @cindex downloading package sources
5360 When writing a package definition, developers typically need to download
5361 a source tarball, compute its SHA256 hash, and write that
5362 hash in the package definition (@pxref{Defining Packages}). The
5363 @command{guix download} tool helps with this task: it downloads a file
5364 from the given URI, adds it to the store, and prints both its file name
5365 in the store and its SHA256 hash.
5367 The fact that the downloaded file is added to the store saves bandwidth:
5368 when the developer eventually tries to build the newly defined package
5369 with @command{guix build}, the source tarball will not have to be
5370 downloaded again because it is already in the store. It is also a
5371 convenient way to temporarily stash files, which may be deleted
5372 eventually (@pxref{Invoking guix gc}).
5374 The @command{guix download} command supports the same URIs as used in
5375 package definitions. In particular, it supports @code{mirror://} URIs.
5376 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5377 Guile bindings for GnuTLS are available in the user's environment; when
5378 they are not available, an error is raised. @xref{Guile Preparations,
5379 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5380 GnuTLS-Guile}, for more information.
5382 @command{guix download} verifies HTTPS server certificates by loading
5383 the certificates of X.509 authorities from the directory pointed to by
5384 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5385 Certificates}), unless @option{--no-check-certificate} is used.
5387 The following options are available:
5390 @item --format=@var{fmt}
5392 Write the hash in the format specified by @var{fmt}. For more
5393 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5395 @item --no-check-certificate
5396 Do not validate the X.509 certificates of HTTPS servers.
5398 When using this option, you have @emph{absolutely no guarantee} that you
5399 are communicating with the authentic server responsible for the given
5400 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5402 @item --output=@var{file}
5403 @itemx -o @var{file}
5404 Save the downloaded file to @var{file} instead of adding it to the
5408 @node Invoking guix hash
5409 @section Invoking @command{guix hash}
5411 @cindex @command{guix hash}
5412 The @command{guix hash} command computes the SHA256 hash of a file.
5413 It is primarily a convenience tool for anyone contributing to the
5414 distribution: it computes the cryptographic hash of a file, which can be
5415 used in the definition of a package (@pxref{Defining Packages}).
5417 The general syntax is:
5420 guix hash @var{option} @var{file}
5423 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5424 hash of data read from standard input. @command{guix hash} has the
5429 @item --format=@var{fmt}
5431 Write the hash in the format specified by @var{fmt}.
5433 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5434 (@code{hex} and @code{hexadecimal} can be used as well).
5436 If the @option{--format} option is not specified, @command{guix hash}
5437 will output the hash in @code{nix-base32}. This representation is used
5438 in the definitions of packages.
5442 Compute the hash on @var{file} recursively.
5444 In this case, the hash is computed on an archive containing @var{file},
5445 including its children if it is a directory. Some of the metadata of
5446 @var{file} is part of the archive; for instance, when @var{file} is a
5447 regular file, the hash is different depending on whether @var{file} is
5448 executable or not. Metadata such as time stamps has no impact on the
5449 hash (@pxref{Invoking guix archive}).
5450 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5455 When combined with @option{--recursive}, exclude version control system
5456 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5459 As an example, here is how you would compute the hash of a Git checkout,
5460 which is useful when using the @code{git-fetch} method (@pxref{origin
5464 $ git clone http://example.org/foo.git
5470 @node Invoking guix import
5471 @section Invoking @command{guix import}
5473 @cindex importing packages
5474 @cindex package import
5475 @cindex package conversion
5476 @cindex Invoking @command{guix import}
5477 The @command{guix import} command is useful for people who would like to
5478 add a package to the distribution with as little work as
5479 possible---a legitimate demand. The command knows of a few
5480 repositories from which it can ``import'' package metadata. The result
5481 is a package definition, or a template thereof, in the format we know
5482 (@pxref{Defining Packages}).
5484 The general syntax is:
5487 guix import @var{importer} @var{options}@dots{}
5490 @var{importer} specifies the source from which to import package
5491 metadata, and @var{options} specifies a package identifier and other
5492 options specific to @var{importer}. Currently, the available
5497 Import metadata for the given GNU package. This provides a template
5498 for the latest version of that GNU package, including the hash of its
5499 source tarball, and its canonical synopsis and description.
5501 Additional information such as the package dependencies and its
5502 license needs to be figured out manually.
5504 For example, the following command returns a package definition for
5508 guix import gnu hello
5511 Specific command-line options are:
5514 @item --key-download=@var{policy}
5515 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5516 keys when verifying the package signature. @xref{Invoking guix
5517 refresh, @code{--key-download}}.
5522 Import metadata from the @uref{https://pypi.python.org/, Python Package
5523 Index}@footnote{This functionality requires Guile-JSON to be installed.
5524 @xref{Requirements}.}. Information is taken from the JSON-formatted
5525 description available at @code{pypi.python.org} and usually includes all
5526 the relevant information, including package dependencies. For maximum
5527 efficiency, it is recommended to install the @command{unzip} utility, so
5528 that the importer can unzip Python wheels and gather data from them.
5530 The command below imports metadata for the @code{itsdangerous} Python
5534 guix import pypi itsdangerous
5539 Import metadata from @uref{https://rubygems.org/,
5540 RubyGems}@footnote{This functionality requires Guile-JSON to be
5541 installed. @xref{Requirements}.}. Information is taken from the
5542 JSON-formatted description available at @code{rubygems.org} and includes
5543 most relevant information, including runtime dependencies. There are
5544 some caveats, however. The metadata doesn't distinguish between
5545 synopses and descriptions, so the same string is used for both fields.
5546 Additionally, the details of non-Ruby dependencies required to build
5547 native extensions is unavailable and left as an exercise to the
5550 The command below imports metadata for the @code{rails} Ruby package:
5553 guix import gem rails
5558 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5559 functionality requires Guile-JSON to be installed.
5560 @xref{Requirements}.}.
5561 Information is taken from the JSON-formatted metadata provided through
5562 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5563 relevant information, such as module dependencies. License information
5564 should be checked closely. If Perl is available in the store, then the
5565 @code{corelist} utility will be used to filter core modules out of the
5566 list of dependencies.
5568 The command command below imports metadata for the @code{Acme::Boolean}
5572 guix import cpan Acme::Boolean
5577 @cindex Bioconductor
5578 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5579 central repository for the @uref{http://r-project.org, GNU@tie{}R
5580 statistical and graphical environment}.
5582 Information is extracted from the @code{DESCRIPTION} file of the package.
5584 The command command below imports metadata for the @code{Cairo}
5588 guix import cran Cairo
5591 When @code{--recursive} is added, the importer will traverse the
5592 dependency graph of the given upstream package recursively and generate
5593 package expressions for all those packages that are not yet in Guix.
5595 When @code{--archive=bioconductor} is added, metadata is imported from
5596 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5597 packages for for the analysis and comprehension of high-throughput
5598 genomic data in bioinformatics.
5600 Information is extracted from the @code{DESCRIPTION} file of a package
5601 published on the web interface of the Bioconductor SVN repository.
5603 The command below imports metadata for the @code{GenomicRanges}
5607 guix import cran --archive=bioconductor GenomicRanges
5611 Import metadata from a local copy of the source of the
5612 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5613 relies on the @command{nix-instantiate} command of
5614 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5615 typically written in a mixture of Nix-language and Bash code. This
5616 command only imports the high-level package structure that is written in
5617 the Nix language. It normally includes all the basic fields of a
5620 When importing a GNU package, the synopsis and descriptions are replaced
5621 by their canonical upstream variant.
5623 Usually, you will first need to do:
5626 export NIX_REMOTE=daemon
5630 so that @command{nix-instantiate} does not try to open the Nix database.
5632 As an example, the command below imports the package definition of
5633 LibreOffice (more precisely, it imports the definition of the package
5634 bound to the @code{libreoffice} top-level attribute):
5637 guix import nix ~/path/to/nixpkgs libreoffice
5642 Import metadata from the Haskell community's central package archive
5643 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5644 Cabal files and includes all the relevant information, including package
5647 Specific command-line options are:
5652 Read a Cabal file from standard input.
5653 @item --no-test-dependencies
5655 Do not include dependencies required only by the test suites.
5656 @item --cabal-environment=@var{alist}
5657 @itemx -e @var{alist}
5658 @var{alist} is a Scheme alist defining the environment in which the
5659 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5660 @code{arch}, @code{impl} and a string representing the name of a flag.
5661 The value associated with a flag has to be either the symbol
5662 @code{true} or @code{false}. The value associated with other keys
5663 has to conform to the Cabal file format definition. The default value
5664 associated with the keys @code{os}, @code{arch} and @code{impl} is
5665 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5668 The command below imports metadata for the latest version of the
5669 @code{HTTP} Haskell package without including test dependencies and
5670 specifying the value of the flag @samp{network-uri} as @code{false}:
5673 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5676 A specific package version may optionally be specified by following the
5677 package name by an at-sign and a version number as in the following example:
5680 guix import hackage mtl@@2.1.3.1
5685 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5686 It takes a package name, looks up the package version included in a
5687 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5688 release and uses the @code{hackage} importer to retrieve its metadata.
5689 Note that it is up to you to select an LTS release compatible with the
5690 GHC compiler used by Guix.
5692 Specific command-line options are:
5695 @item --no-test-dependencies
5697 Do not include dependencies required only by the test suites.
5698 @item --lts-version=@var{version}
5699 @itemx -r @var{version}
5700 @var{version} is the desired LTS release version. If omitted the latest
5704 The command below imports metadata for the @code{HTTP} Haskell package
5705 included in the LTS Stackage release version 7.18:
5708 guix import stackage --lts-version=7.18 HTTP
5713 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5714 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5716 Specific command-line options are:
5719 @item --archive=@var{repo}
5720 @itemx -a @var{repo}
5721 @var{repo} identifies the archive repository from which to retrieve the
5722 information. Currently the supported repositories and their identifiers
5726 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5727 identifier. This is the default.
5729 Packages from @code{elpa.gnu.org} are signed with one of the keys
5730 contained in the GnuPG keyring at
5731 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5732 @code{emacs} package (@pxref{Package Installation, ELPA package
5733 signatures,, emacs, The GNU Emacs Manual}).
5736 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5737 @code{melpa-stable} identifier.
5740 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5747 Import metadata from the crates.io Rust package repository
5748 @uref{https://crates.io, crates.io}.
5751 The structure of the @command{guix import} code is modular. It would be
5752 useful to have more importers for other package formats, and your help
5753 is welcome here (@pxref{Contributing}).
5755 @node Invoking guix refresh
5756 @section Invoking @command{guix refresh}
5758 @cindex @command {guix refresh}
5759 The primary audience of the @command{guix refresh} command is developers
5760 of the GNU software distribution. By default, it reports any packages
5761 provided by the distribution that are outdated compared to the latest
5762 upstream version, like this:
5766 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5767 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5770 Alternately, one can specify packages to consider, in which case a
5771 warning is emitted for packages that lack an updater:
5774 $ guix refresh coreutils guile guile-ssh
5775 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5776 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5779 @command{guix refresh} browses the upstream repository of each package and determines
5780 the highest version number of the releases therein. The command
5781 knows how to update specific types of packages: GNU packages, ELPA
5782 packages, etc.---see the documentation for @option{--type} below. There
5783 are many packages, though, for which it lacks a method to determine
5784 whether a new upstream release is available. However, the mechanism is
5785 extensible, so feel free to get in touch with us to add a new method!
5787 When passed @code{--update}, it modifies distribution source files to
5788 update the version numbers and source tarball hashes of those package
5789 recipes (@pxref{Defining Packages}). This is achieved by downloading
5790 each package's latest source tarball and its associated OpenPGP
5791 signature, authenticating the downloaded tarball against its signature
5792 using @command{gpg}, and finally computing its hash. When the public
5793 key used to sign the tarball is missing from the user's keyring, an
5794 attempt is made to automatically retrieve it from a public key server;
5795 when this is successful, the key is added to the user's keyring; otherwise,
5796 @command{guix refresh} reports an error.
5798 The following options are supported:
5802 @item --expression=@var{expr}
5803 @itemx -e @var{expr}
5804 Consider the package @var{expr} evaluates to.
5806 This is useful to precisely refer to a package, as in this example:
5809 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5812 This command lists the dependents of the ``final'' libc (essentially all
5817 Update distribution source files (package recipes) in place. This is
5818 usually run from a checkout of the Guix source tree (@pxref{Running
5819 Guix Before It Is Installed}):
5822 $ ./pre-inst-env guix refresh -s non-core -u
5825 @xref{Defining Packages}, for more information on package definitions.
5827 @item --select=[@var{subset}]
5828 @itemx -s @var{subset}
5829 Select all the packages in @var{subset}, one of @code{core} or
5832 The @code{core} subset refers to all the packages at the core of the
5833 distribution---i.e., packages that are used to build ``everything
5834 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5835 changing one of these packages in the distribution entails a rebuild of
5836 all the others. Thus, such updates are an inconvenience to users in
5837 terms of build time or bandwidth used to achieve the upgrade.
5839 The @code{non-core} subset refers to the remaining packages. It is
5840 typically useful in cases where an update of the core packages would be
5843 @item --type=@var{updater}
5844 @itemx -t @var{updater}
5845 Select only packages handled by @var{updater} (may be a comma-separated
5846 list of updaters). Currently, @var{updater} may be one of:
5850 the updater for GNU packages;
5852 the updater for GNOME packages;
5854 the updater for KDE packages;
5856 the updater for X.org packages;
5858 the updater for packages hosted on kernel.org;
5860 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5862 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5864 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5866 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5868 the updater for @uref{https://pypi.python.org, PyPI} packages.
5870 the updater for @uref{https://rubygems.org, RubyGems} packages.
5872 the updater for @uref{https://github.com, GitHub} packages.
5874 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5876 the updater for @uref{https://www.stackage.org, Stackage} packages.
5878 the updater for @uref{https://crates.io, Crates} packages.
5881 For instance, the following command only checks for updates of Emacs
5882 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5885 $ guix refresh --type=elpa,cran
5886 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5887 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5892 In addition, @command{guix refresh} can be passed one or more package
5893 names, as in this example:
5896 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5900 The command above specifically updates the @code{emacs} and
5901 @code{idutils} packages. The @code{--select} option would have no
5902 effect in this case.
5904 When considering whether to upgrade a package, it is sometimes
5905 convenient to know which packages would be affected by the upgrade and
5906 should be checked for compatibility. For this the following option may
5907 be used when passing @command{guix refresh} one or more package names:
5911 @item --list-updaters
5913 List available updaters and exit (see @option{--type} above.)
5915 For each updater, display the fraction of packages it covers; at the
5916 end, display the fraction of packages covered by all these updaters.
5918 @item --list-dependent
5920 List top-level dependent packages that would need to be rebuilt as a
5921 result of upgrading one or more packages.
5923 @xref{Invoking guix graph, the @code{reverse-package} type of
5924 @command{guix graph}}, for information on how to visualize the list of
5925 dependents of a package.
5929 Be aware that the @code{--list-dependent} option only
5930 @emph{approximates} the rebuilds that would be required as a result of
5931 an upgrade. More rebuilds might be required under some circumstances.
5934 $ guix refresh --list-dependent flex
5935 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5936 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
5939 The command above lists a set of packages that could be built to check
5940 for compatibility with an upgraded @code{flex} package.
5942 The following options can be used to customize GnuPG operation:
5946 @item --gpg=@var{command}
5947 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5948 for in @code{$PATH}.
5950 @item --key-download=@var{policy}
5951 Handle missing OpenPGP keys according to @var{policy}, which may be one
5956 Always download missing OpenPGP keys from the key server, and add them
5957 to the user's GnuPG keyring.
5960 Never try to download missing OpenPGP keys. Instead just bail out.
5963 When a package signed with an unknown OpenPGP key is encountered, ask
5964 the user whether to download it or not. This is the default behavior.
5967 @item --key-server=@var{host}
5968 Use @var{host} as the OpenPGP key server when importing a public key.
5972 The @code{github} updater uses the
5973 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5974 releases. When used repeatedly e.g. when refreshing all packages,
5975 GitHub will eventually refuse to answer any further API requests. By
5976 default 60 API requests per hour are allowed, and a full refresh on all
5977 GitHub packages in Guix requires more than this. Authentication with
5978 GitHub through the use of an API token alleviates these limits. To use
5979 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5980 token procured from @uref{https://github.com/settings/tokens} or
5984 @node Invoking guix lint
5985 @section Invoking @command{guix lint}
5987 @cindex @command{guix lint}
5988 @cindex package, checking for errors
5989 The @command{guix lint} command is meant to help package developers avoid
5990 common errors and use a consistent style. It runs a number of checks on
5991 a given set of packages in order to find common mistakes in their
5992 definitions. Available @dfn{checkers} include (see
5993 @code{--list-checkers} for a complete list):
5998 Validate certain typographical and stylistic rules about package
5999 descriptions and synopses.
6001 @item inputs-should-be-native
6002 Identify inputs that should most likely be native inputs.
6007 @itemx source-file-name
6008 Probe @code{home-page} and @code{source} URLs and report those that are
6009 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6010 the source file name is meaningful, e.g. is not
6011 just a version number or ``git-checkout'', without a declared
6012 @code{file-name} (@pxref{origin Reference}).
6015 @cindex security vulnerabilities
6016 @cindex CVE, Common Vulnerabilities and Exposures
6017 Report known vulnerabilities found in the Common Vulnerabilities and
6018 Exposures (CVE) databases of the current and past year
6019 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6022 To view information about a particular vulnerability, visit pages such as:
6026 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6028 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6032 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6033 @code{CVE-2015-7554}.
6035 Package developers can specify in package recipes the
6036 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6037 name and version of the package when they differ from the name that Guix
6038 uses, as in this example:
6044 ;; CPE calls this package "grub2".
6045 (properties '((cpe-name . "grub2"))))
6049 Warn about obvious source code formatting issues: trailing white space,
6050 use of tabulations, etc.
6053 The general syntax is:
6056 guix lint @var{options} @var{package}@dots{}
6059 If no package is given on the command line, then all packages are checked.
6060 The @var{options} may be zero or more of the following:
6063 @item --list-checkers
6065 List and describe all the available checkers that will be run on packages
6070 Only enable the checkers specified in a comma-separated list using the
6071 names returned by @code{--list-checkers}.
6075 @node Invoking guix size
6076 @section Invoking @command{guix size}
6079 @cindex package size
6081 @cindex @command{guix size}
6082 The @command{guix size} command helps package developers profile the
6083 disk usage of packages. It is easy to overlook the impact of an
6084 additional dependency added to a package, or the impact of using a
6085 single output for a package that could easily be split (@pxref{Packages
6086 with Multiple Outputs}). Such are the typical issues that
6087 @command{guix size} can highlight.
6089 The command can be passed a package specification such as @code{gcc@@4.8}
6090 or @code{guile:debug}, or a file name in the store. Consider this
6094 $ guix size coreutils
6095 store item total self
6096 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6097 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6098 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6099 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6100 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6101 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6105 The store items listed here constitute the @dfn{transitive closure} of
6106 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6107 would be returned by:
6110 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6113 Here the output shows three columns next to store items. The first column,
6114 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6115 the store item---that is, its own size plus the size of all its
6116 dependencies. The next column, labeled ``self'', shows the size of the
6117 item itself. The last column shows the ratio of the size of the item
6118 itself to the space occupied by all the items listed here.
6120 In this example, we see that the closure of Coreutils weighs in at
6121 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6122 large fraction of the closure is not a problem @i{per se} because it is
6123 always available on the system anyway.)
6125 When the package passed to @command{guix size} is available in the
6126 store, @command{guix size} queries the daemon to determine its
6127 dependencies, and measures its size in the store, similar to @command{du
6128 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6131 When the given package is @emph{not} in the store, @command{guix size}
6132 reports information based on the available substitutes
6133 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6134 store items that are not even on disk, only available remotely.
6136 You can also specify several package names:
6139 $ guix size coreutils grep sed bash
6140 store item total self
6141 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6142 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6143 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6144 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6150 In this example we see that the combination of the four packages takes
6151 102.3@tie{}MiB in total, which is much less than the sum of each closure
6152 since they have a lot of dependencies in common.
6154 The available options are:
6158 @item --substitute-urls=@var{urls}
6159 Use substitute information from @var{urls}.
6160 @xref{client-substitute-urls, the same option for @code{guix build}}.
6162 @item --map-file=@var{file}
6163 Write a graphical map of disk usage in PNG format to @var{file}.
6165 For the example above, the map looks like this:
6167 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6168 produced by @command{guix size}}
6170 This option requires that
6171 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6172 installed and visible in Guile's module search path. When that is not
6173 the case, @command{guix size} fails as it tries to load it.
6175 @item --system=@var{system}
6176 @itemx -s @var{system}
6177 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6181 @node Invoking guix graph
6182 @section Invoking @command{guix graph}
6185 @cindex @command{guix graph}
6186 @cindex package dependencies
6187 Packages and their dependencies form a @dfn{graph}, specifically a
6188 directed acyclic graph (DAG). It can quickly become difficult to have a
6189 mental model of the package DAG, so the @command{guix graph} command
6190 provides a visual representation of the DAG. By default,
6191 @command{guix graph} emits a DAG representation in the input format of
6192 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6193 directly to the @command{dot} command of Graphviz. It can also emit an
6194 HTML page with embedded JavaScript code to display a ``chord diagram''
6195 in a Web browser, using the @uref{https://d3js.org/, d3.js} library.
6196 The general syntax is:
6199 guix graph @var{options} @var{package}@dots{}
6202 For example, the following command generates a PDF file representing the
6203 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6207 guix graph coreutils | dot -Tpdf > dag.pdf
6210 The output looks like this:
6212 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6214 Nice little graph, no?
6216 But there is more than one graph! The one above is concise: it is the
6217 graph of package objects, omitting implicit inputs such as GCC, libc,
6218 grep, etc. It is often useful to have such a concise graph, but
6219 sometimes one may want to see more details. @command{guix graph} supports
6220 several types of graphs, allowing you to choose the level of detail:
6224 This is the default type used in the example above. It shows the DAG of
6225 package objects, excluding implicit dependencies. It is concise, but
6226 filters out many details.
6228 @item reverse-package
6229 This shows the @emph{reverse} DAG of packages. For example:
6232 guix graph --type=reverse-package ocaml
6235 ... yields the graph of packages that depend on OCaml.
6237 Note that for core packages this can yield huge graphs. If all you want
6238 is to know the number of packages that depend on a given package, use
6239 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6240 @option{--list-dependent}}).
6243 This is the package DAG, @emph{including} implicit inputs.
6245 For instance, the following command:
6248 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6251 ... yields this bigger graph:
6253 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6255 At the bottom of the graph, we see all the implicit inputs of
6256 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6258 Now, note that the dependencies of these implicit inputs---that is, the
6259 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6260 here, for conciseness.
6263 Similar to @code{bag-emerged}, but this time including all the bootstrap
6266 @item bag-with-origins
6267 Similar to @code{bag}, but also showing origins and their dependencies.
6270 This is the most detailed representation: It shows the DAG of
6271 derivations (@pxref{Derivations}) and plain store items. Compared to
6272 the above representation, many additional nodes are visible, including
6273 build scripts, patches, Guile modules, etc.
6275 For this type of graph, it is also possible to pass a @file{.drv} file
6276 name instead of a package name, as in:
6279 guix graph -t derivation `guix system build -d my-config.scm`
6283 All the types above correspond to @emph{build-time dependencies}. The
6284 following graph type represents the @emph{run-time dependencies}:
6288 This is the graph of @dfn{references} of a package output, as returned
6289 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6291 If the given package output is not available in the store, @command{guix
6292 graph} attempts to obtain dependency information from substitutes.
6294 Here you can also pass a store file name instead of a package name. For
6295 example, the command below produces the reference graph of your profile
6296 (which can be big!):
6299 guix graph -t references `readlink -f ~/.guix-profile`
6303 This is the graph of the @dfn{referrers} of a store item, as returned by
6304 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6306 This relies exclusively on local information from your store. For
6307 instance, let us suppose that the current Inkscape is available in 10
6308 profiles on your machine; @command{guix graph -t referrers inkscape}
6309 will show a graph rooted at Inkscape and with those 10 profiles linked
6312 It can help determine what is preventing a store item from being garbage
6317 The available options are the following:
6320 @item --type=@var{type}
6321 @itemx -t @var{type}
6322 Produce a graph output of @var{type}, where @var{type} must be one of
6323 the values listed above.
6326 List the supported graph types.
6328 @item --backend=@var{backend}
6329 @itemx -b @var{backend}
6330 Produce a graph using the selected @var{backend}.
6332 @item --list-backends
6333 List the supported graph backends.
6335 Currently, the available backends are Graphviz and d3.js.
6337 @item --expression=@var{expr}
6338 @itemx -e @var{expr}
6339 Consider the package @var{expr} evaluates to.
6341 This is useful to precisely refer to a package, as in this example:
6344 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6349 @node Invoking guix environment
6350 @section Invoking @command{guix environment}
6352 @cindex reproducible build environments
6353 @cindex development environments
6354 @cindex @command{guix environment}
6355 @cindex environment, package build environment
6356 The purpose of @command{guix environment} is to assist hackers in
6357 creating reproducible development environments without polluting their
6358 package profile. The @command{guix environment} tool takes one or more
6359 packages, builds all of their inputs, and creates a shell
6360 environment to use them.
6362 The general syntax is:
6365 guix environment @var{options} @var{package}@dots{}
6368 The following example spawns a new shell set up for the development of
6372 guix environment guile
6375 If the needed dependencies are not built yet, @command{guix environment}
6376 automatically builds them. The environment of the new shell is an augmented
6377 version of the environment that @command{guix environment} was run in.
6378 It contains the necessary search paths for building the given package
6379 added to the existing environment variables. To create a ``pure''
6380 environment, in which the original environment variables have been unset,
6381 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6382 environment variables such as @code{PATH} in their @file{~/.bashrc}
6383 file. As a consequence, when @code{guix environment} launches it, Bash
6384 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6385 environment variables. It is an error to define such environment
6386 variables in @file{.bashrc}; instead, they should be defined in
6387 @file{.bash_profile}, which is sourced only by log-in shells.
6388 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6389 details on Bash start-up files.}.
6391 @vindex GUIX_ENVIRONMENT
6392 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6393 variable in the shell it spawns; its value is the file name of the
6394 profile of this environment. This allows users to, say, define a
6395 specific prompt for development environments in their @file{.bashrc}
6396 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6399 if [ -n "$GUIX_ENVIRONMENT" ]
6401 export PS1="\u@@\h \w [dev]\$ "
6406 ... or to browse the profile:
6409 $ ls "$GUIX_ENVIRONMENT/bin"
6412 Additionally, more than one package may be specified, in which case the
6413 union of the inputs for the given packages are used. For example, the
6414 command below spawns a shell where all of the dependencies of both Guile
6415 and Emacs are available:
6418 guix environment guile emacs
6421 Sometimes an interactive shell session is not desired. An arbitrary
6422 command may be invoked by placing the @code{--} token to separate the
6423 command from the rest of the arguments:
6426 guix environment guile -- make -j4
6429 In other situations, it is more convenient to specify the list of
6430 packages needed in the environment. For example, the following command
6431 runs @command{python} from an environment containing Python@tie{}2.7 and
6435 guix environment --ad-hoc python2-numpy python-2.7 -- python
6438 Furthermore, one might want the dependencies of a package and also some
6439 additional packages that are not build-time or runtime dependencies, but
6440 are useful when developing nonetheless. Because of this, the
6441 @code{--ad-hoc} flag is positional. Packages appearing before
6442 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6443 added to the environment. Packages appearing after are interpreted as
6444 packages that will be added to the environment directly. For example,
6445 the following command creates a Guix development environment that
6446 additionally includes Git and strace:
6449 guix environment guix --ad-hoc git strace
6452 Sometimes it is desirable to isolate the environment as much as
6453 possible, for maximal purity and reproducibility. In particular, when
6454 using Guix on a host distro that is not GuixSD, it is desirable to
6455 prevent access to @file{/usr/bin} and other system-wide resources from
6456 the development environment. For example, the following command spawns
6457 a Guile REPL in a ``container'' where only the store and the current
6458 working directory are mounted:
6461 guix environment --ad-hoc --container guile -- guile
6465 The @code{--container} option requires Linux-libre 3.19 or newer.
6468 The available options are summarized below.
6471 @item --root=@var{file}
6472 @itemx -r @var{file}
6473 @cindex persistent environment
6474 @cindex garbage collector root, for environments
6475 Make @var{file} a symlink to the profile for this environment, and
6476 register it as a garbage collector root.
6478 This is useful if you want to protect your environment from garbage
6479 collection, to make it ``persistent''.
6481 When this option is omitted, the environment is protected from garbage
6482 collection only for the duration of the @command{guix environment}
6483 session. This means that next time you recreate the same environment,
6484 you could have to rebuild or re-download packages.
6486 @item --expression=@var{expr}
6487 @itemx -e @var{expr}
6488 Create an environment for the package or list of packages that
6489 @var{expr} evaluates to.
6491 For example, running:
6494 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6497 starts a shell with the environment for this specific variant of the
6503 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6506 starts a shell with all the GuixSD base packages available.
6508 The above commands only use the default output of the given packages.
6509 To select other outputs, two element tuples can be specified:
6512 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6515 @item --load=@var{file}
6516 @itemx -l @var{file}
6517 Create an environment for the package or list of packages that the code
6518 within @var{file} evaluates to.
6520 As an example, @var{file} might contain a definition like this
6521 (@pxref{Defining Packages}):
6524 @verbatiminclude environment-gdb.scm
6528 Include all specified packages in the resulting environment, as if an
6529 @i{ad hoc} package were defined with them as inputs. This option is
6530 useful for quickly creating an environment without having to write a
6531 package expression to contain the desired inputs.
6533 For instance, the command:
6536 guix environment --ad-hoc guile guile-sdl -- guile
6539 runs @command{guile} in an environment where Guile and Guile-SDL are
6542 Note that this example implicitly asks for the default output of
6543 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6544 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6545 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6547 This option may be composed with the default behavior of @command{guix
6548 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6549 as packages whose dependencies will be added to the environment, the
6550 default behavior. Packages appearing after are interpreted as packages
6551 that will be added to the environment directly.
6554 Unset existing environment variables when building the new environment.
6555 This has the effect of creating an environment in which search paths
6556 only contain package inputs.
6558 @item --search-paths
6559 Display the environment variable definitions that make up the
6562 @item --system=@var{system}
6563 @itemx -s @var{system}
6564 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6569 Run @var{command} within an isolated container. The current working
6570 directory outside the container is mapped inside the container.
6571 Additionally, a dummy home directory is created that matches the current
6572 user's home directory, and @file{/etc/passwd} is configured accordingly.
6573 The spawned process runs as the current user outside the container, but
6574 has root privileges in the context of the container.
6578 For containers, share the network namespace with the host system.
6579 Containers created without this flag only have access to the loopback
6582 @item --expose=@var{source}[=@var{target}]
6583 For containers, expose the file system @var{source} from the host system
6584 as the read-only file system @var{target} within the container. If
6585 @var{target} is not specified, @var{source} is used as the target mount
6586 point in the container.
6588 The example below spawns a Guile REPL in a container in which the user's
6589 home directory is accessible read-only via the @file{/exchange}
6593 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6596 @item --share=@var{source}[=@var{target}]
6597 For containers, share the file system @var{source} from the host system
6598 as the writable file system @var{target} within the container. If
6599 @var{target} is not specified, @var{source} is used as the target mount
6600 point in the container.
6602 The example below spawns a Guile REPL in a container in which the user's
6603 home directory is accessible for both reading and writing via the
6604 @file{/exchange} directory:
6607 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6611 @command{guix environment}
6612 also supports all of the common build options that @command{guix
6613 build} supports (@pxref{Common Build Options}).
6616 @node Invoking guix publish
6617 @section Invoking @command{guix publish}
6619 @cindex @command{guix publish}
6620 The purpose of @command{guix publish} is to enable users to easily share
6621 their store with others, who can then use it as a substitute server
6622 (@pxref{Substitutes}).
6624 When @command{guix publish} runs, it spawns an HTTP server which allows
6625 anyone with network access to obtain substitutes from it. This means
6626 that any machine running Guix can also act as if it were a build farm,
6627 since the HTTP interface is compatible with Hydra, the software behind
6628 the @code{hydra.gnu.org} build farm.
6630 For security, each substitute is signed, allowing recipients to check
6631 their authenticity and integrity (@pxref{Substitutes}). Because
6632 @command{guix publish} uses the signing key of the system, which is only
6633 readable by the system administrator, it must be started as root; the
6634 @code{--user} option makes it drop root privileges early on.
6636 The signing key pair must be generated before @command{guix publish} is
6637 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6640 The general syntax is:
6643 guix publish @var{options}@dots{}
6646 Running @command{guix publish} without any additional arguments will
6647 spawn an HTTP server on port 8080:
6653 Once a publishing server has been authorized (@pxref{Invoking guix
6654 archive}), the daemon may download substitutes from it:
6657 guix-daemon --substitute-urls=http://example.org:8080
6660 By default, @command{guix publish} compresses archives on the fly as it
6661 serves them. This ``on-the-fly'' mode is convenient in that it requires
6662 no setup and is immediately available. However, when serving lots of
6663 clients, we recommend using the @option{--cache} option, which enables
6664 caching of the archives before they are sent to clients---see below for
6667 As a bonus, @command{guix publish} also serves as a content-addressed
6668 mirror for source files referenced in @code{origin} records
6669 (@pxref{origin Reference}). For instance, assuming @command{guix
6670 publish} is running on @code{example.org}, the following URL returns the
6671 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6672 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6675 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6678 Obviously, these URLs only work for files that are in the store; in
6679 other cases, they return 404 (``Not Found'').
6681 The following options are available:
6684 @item --port=@var{port}
6685 @itemx -p @var{port}
6686 Listen for HTTP requests on @var{port}.
6688 @item --listen=@var{host}
6689 Listen on the network interface for @var{host}. The default is to
6690 accept connections from any interface.
6692 @item --user=@var{user}
6693 @itemx -u @var{user}
6694 Change privileges to @var{user} as soon as possible---i.e., once the
6695 server socket is open and the signing key has been read.
6697 @item --compression[=@var{level}]
6698 @itemx -C [@var{level}]
6699 Compress data using the given @var{level}. When @var{level} is zero,
6700 disable compression. The range 1 to 9 corresponds to different gzip
6701 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6704 Unless @option{--cache} is used, compression occurs on the fly and
6705 the compressed streams are not
6706 cached. Thus, to reduce load on the machine that runs @command{guix
6707 publish}, it may be a good idea to choose a low compression level, to
6708 run @command{guix publish} behind a caching proxy, or to use
6709 @option{--cache}. Using @option{--cache} has the advantage that it
6710 allows @command{guix publish} to add @code{Content-Length} HTTP header
6713 @item --cache=@var{directory}
6714 @itemx -c @var{directory}
6715 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6716 and only serve archives that are in cache.
6718 When this option is omitted, archives and meta-data are created
6719 on-the-fly. This can reduce the available bandwidth, especially when
6720 compression is enabled, since this may become CPU-bound. Another
6721 drawback of the default mode is that the length of archives is not known
6722 in advance, so @command{guix publish} does not add a
6723 @code{Content-Length} HTTP header to its responses, which in turn
6724 prevents clients from knowing the amount of data being downloaded.
6726 Conversely, when @option{--cache} is used, the first request for a store
6727 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6728 background process to @dfn{bake} the archive---computing its
6729 @code{.narinfo} and compressing the archive, if needed. Once the
6730 archive is cached in @var{directory}, subsequent requests succeed and
6731 are served directly from the cache, which guarantees that clients get
6732 the best possible bandwidth.
6734 The ``baking'' process is performed by worker threads. By default, one
6735 thread per CPU core is created, but this can be customized. See
6736 @option{--workers} below.
6738 When @option{--ttl} is used, cached entries are automatically deleted
6739 when they have expired.
6741 @item --workers=@var{N}
6742 When @option{--cache} is used, request the allocation of @var{N} worker
6743 threads to ``bake'' archives.
6745 @item --ttl=@var{ttl}
6746 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6747 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6748 days, @code{1m} means 1 month, and so on.
6750 This allows the user's Guix to keep substitute information in cache for
6751 @var{ttl}. However, note that @code{guix publish} does not itself
6752 guarantee that the store items it provides will indeed remain available
6753 for as long as @var{ttl}.
6755 Additionally, when @option{--cache} is used, cached entries that have
6756 not been accessed for @var{ttl} may be deleted.
6758 @item --nar-path=@var{path}
6759 Use @var{path} as the prefix for the URLs of ``nar'' files
6760 (@pxref{Invoking guix archive, normalized archives}).
6762 By default, nars are served at a URL such as
6763 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6764 change the @code{/nar} part to @var{path}.
6766 @item --public-key=@var{file}
6767 @itemx --private-key=@var{file}
6768 Use the specific @var{file}s as the public/private key pair used to sign
6769 the store items being published.
6771 The files must correspond to the same key pair (the private key is used
6772 for signing and the public key is merely advertised in the signature
6773 metadata). They must contain keys in the canonical s-expression format
6774 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6775 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6776 @file{/etc/guix/signing-key.sec} are used.
6778 @item --repl[=@var{port}]
6779 @itemx -r [@var{port}]
6780 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6781 Reference Manual}) on @var{port} (37146 by default). This is used
6782 primarily for debugging a running @command{guix publish} server.
6785 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6786 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6787 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6788 @code{guix-publish-service-type}}).
6790 If you are instead running Guix on a ``foreign distro'', follow these
6795 If your host distro uses the systemd init system:
6798 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6799 /etc/systemd/system/
6800 # systemctl start guix-publish && systemctl enable guix-publish
6804 If your host distro uses the Upstart init system:
6807 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6808 # start guix-publish
6812 Otherwise, proceed similarly with your distro's init system.
6815 @node Invoking guix challenge
6816 @section Invoking @command{guix challenge}
6818 @cindex reproducible builds
6819 @cindex verifiable builds
6820 @cindex @command{guix challenge}
6822 Do the binaries provided by this server really correspond to the source
6823 code it claims to build? Is a package build process deterministic?
6824 These are the questions the @command{guix challenge} command attempts to
6827 The former is obviously an important question: Before using a substitute
6828 server (@pxref{Substitutes}), one had better @emph{verify} that it
6829 provides the right binaries, and thus @emph{challenge} it. The latter
6830 is what enables the former: If package builds are deterministic, then
6831 independent builds of the package should yield the exact same result,
6832 bit for bit; if a server provides a binary different from the one
6833 obtained locally, it may be either corrupt or malicious.
6835 We know that the hash that shows up in @file{/gnu/store} file names is
6836 the hash of all the inputs of the process that built the file or
6837 directory---compilers, libraries, build scripts,
6838 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6839 one store file name should map to exactly one build output.
6840 @command{guix challenge} checks whether there is, indeed, a single
6841 mapping by comparing the build outputs of several independent builds of
6842 any given store item.
6844 The command output looks like this:
6847 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6848 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6849 updating list of substitutes from 'https://guix.example.org'... 100.0%
6850 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6851 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6852 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6853 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6854 /gnu/store/@dots{}-git-2.5.0 contents differ:
6855 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6856 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6857 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6858 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6859 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6860 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6861 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6865 In this example, @command{guix challenge} first scans the store to
6866 determine the set of locally-built derivations---as opposed to store
6867 items that were downloaded from a substitute server---and then queries
6868 all the substitute servers. It then reports those store items for which
6869 the servers obtained a result different from the local build.
6871 @cindex non-determinism, in package builds
6872 As an example, @code{guix.example.org} always gets a different answer.
6873 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6874 case of Git. This might indicate that the build process of Git is
6875 non-deterministic, meaning that its output varies as a function of
6876 various things that Guix does not fully control, in spite of building
6877 packages in isolated environments (@pxref{Features}). Most common
6878 sources of non-determinism include the addition of timestamps in build
6879 results, the inclusion of random numbers, and directory listings sorted
6880 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6883 To find out what is wrong with this Git binary, we can do something along
6884 these lines (@pxref{Invoking guix archive}):
6887 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6888 | guix archive -x /tmp/git
6889 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6892 This command shows the difference between the files resulting from the
6893 local build, and the files resulting from the build on
6894 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6895 diffutils, Comparing and Merging Files}). The @command{diff} command
6896 works great for text files. When binary files differ, a better option
6897 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6898 visualize differences for all kinds of files.
6900 Once you have done that work, you can tell whether the differences are due
6901 to a non-deterministic build process or to a malicious server. We try
6902 hard to remove sources of non-determinism in packages to make it easier
6903 to verify substitutes, but of course, this is a process that
6904 involves not just Guix, but a large part of the free software community.
6905 In the meantime, @command{guix challenge} is one tool to help address
6908 If you are writing packages for Guix, you are encouraged to check
6909 whether @code{hydra.gnu.org} and other substitute servers obtain the
6910 same build result as you did with:
6913 $ guix challenge @var{package}
6917 where @var{package} is a package specification such as
6918 @code{guile@@2.0} or @code{glibc:debug}.
6920 The general syntax is:
6923 guix challenge @var{options} [@var{packages}@dots{}]
6926 When a difference is found between the hash of a locally-built item and
6927 that of a server-provided substitute, or among substitutes provided by
6928 different servers, the command displays it as in the example above and
6929 its exit code is 2 (other non-zero exit codes denote other kinds of
6932 The one option that matters is:
6936 @item --substitute-urls=@var{urls}
6937 Consider @var{urls} the whitespace-separated list of substitute source
6942 Show details about matches (identical contents) in addition to
6943 information about mismatches.
6947 @node Invoking guix copy
6948 @section Invoking @command{guix copy}
6950 @cindex copy, of store items, over SSH
6951 @cindex SSH, copy of store items
6952 @cindex sharing store items across machines
6953 @cindex transferring store items across machines
6954 The @command{guix copy} command copies items from the store of one
6955 machine to that of another machine over a secure shell (SSH)
6956 connection@footnote{This command is available only when Guile-SSH was
6957 found. @xref{Requirements}, for details.}. For example, the following
6958 command copies the @code{coreutils} package, the user's profile, and all
6959 their dependencies over to @var{host}, logged in as @var{user}:
6962 guix copy --to=@var{user}@@@var{host} \
6963 coreutils `readlink -f ~/.guix-profile`
6966 If some of the items to be copied are already present on @var{host},
6967 they are not actually sent.
6969 The command below retrieves @code{libreoffice} and @code{gimp} from
6970 @var{host}, assuming they are available there:
6973 guix copy --from=@var{host} libreoffice gimp
6976 The SSH connection is established using the Guile-SSH client, which is
6977 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6978 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6980 The key used to sign items that are sent must be accepted by the remote
6981 machine. Likewise, the key used by the remote machine to sign items you
6982 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6983 own daemon. @xref{Invoking guix archive}, for more information about
6984 store item authentication.
6986 The general syntax is:
6989 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6992 You must always specify one of the following options:
6995 @item --to=@var{spec}
6996 @itemx --from=@var{spec}
6997 Specify the host to send to or receive from. @var{spec} must be an SSH
6998 spec such as @code{example.org}, @code{charlie@@example.org}, or
6999 @code{charlie@@example.org:2222}.
7002 The @var{items} can be either package names, such as @code{gimp}, or
7003 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7005 When specifying the name of a package to send, it is first built if
7006 needed, unless @option{--dry-run} was specified. Common build options
7007 are supported (@pxref{Common Build Options}).
7010 @node Invoking guix container
7011 @section Invoking @command{guix container}
7013 @cindex @command{guix container}
7015 As of version @value{VERSION}, this tool is experimental. The interface
7016 is subject to radical change in the future.
7019 The purpose of @command{guix container} is to manipulate processes
7020 running within an isolated environment, commonly known as a
7021 ``container'', typically created by the @command{guix environment}
7022 (@pxref{Invoking guix environment}) and @command{guix system container}
7023 (@pxref{Invoking guix system}) commands.
7025 The general syntax is:
7028 guix container @var{action} @var{options}@dots{}
7031 @var{action} specifies the operation to perform with a container, and
7032 @var{options} specifies the context-specific arguments for the action.
7034 The following actions are available:
7038 Execute a command within the context of a running container.
7043 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7046 @var{pid} specifies the process ID of the running container.
7047 @var{program} specifies an executable file name within the root file
7048 system of the container. @var{arguments} are the additional options that
7049 will be passed to @var{program}.
7051 The following command launches an interactive login shell inside a
7052 GuixSD container, started by @command{guix system container}, and whose
7056 guix container exec 9001 /run/current-system/profile/bin/bash --login
7059 Note that the @var{pid} cannot be the parent process of a container. It
7060 must be PID 1 of the container or one of its child processes.
7064 @c *********************************************************************
7065 @node GNU Distribution
7066 @chapter GNU Distribution
7068 @cindex Guix System Distribution
7070 Guix comes with a distribution of the GNU system consisting entirely of
7071 free software@footnote{The term ``free'' here refers to the
7072 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7073 users of that software}.}. The
7074 distribution can be installed on its own (@pxref{System Installation}),
7075 but it is also possible to install Guix as a package manager on top of
7076 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7077 between the two, we refer to the standalone distribution as the Guix
7078 System Distribution, or GuixSD.
7080 The distribution provides core GNU packages such as GNU libc, GCC, and
7081 Binutils, as well as many GNU and non-GNU applications. The complete
7082 list of available packages can be browsed
7083 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7084 running @command{guix package} (@pxref{Invoking guix package}):
7087 guix package --list-available
7090 Our goal is to provide a practical 100% free software distribution of
7091 Linux-based and other variants of GNU, with a focus on the promotion and
7092 tight integration of GNU components, and an emphasis on programs and
7093 tools that help users exert that freedom.
7095 Packages are currently available on the following platforms:
7100 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7103 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7106 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7107 using the EABI hard-float application binary interface (ABI),
7108 and Linux-Libre kernel.
7111 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7112 currently in an experimental stage, with limited support.
7113 @xref{Contributing}, for how to help!
7115 @item mips64el-linux
7116 little-endian 64-bit MIPS processors, specifically the Loongson series,
7117 n32 ABI, and Linux-Libre kernel.
7121 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7124 For information on porting to other architectures or kernels,
7128 * System Installation:: Installing the whole operating system.
7129 * System Configuration:: Configuring the operating system.
7130 * Documentation:: Browsing software user manuals.
7131 * Installing Debugging Files:: Feeding the debugger.
7132 * Security Updates:: Deploying security fixes quickly.
7133 * Package Modules:: Packages from the programmer's viewpoint.
7134 * Packaging Guidelines:: Growing the distribution.
7135 * Bootstrapping:: GNU/Linux built from scratch.
7136 * Porting:: Targeting another platform or kernel.
7139 Building this distribution is a cooperative effort, and you are invited
7140 to join! @xref{Contributing}, for information about how you can help.
7142 @node System Installation
7143 @section System Installation
7145 @cindex installing GuixSD
7146 @cindex Guix System Distribution
7147 This section explains how to install the Guix System Distribution (GuixSD)
7148 on a machine. The Guix package manager can
7149 also be installed on top of a running GNU/Linux system,
7150 @pxref{Installation}.
7154 @c This paragraph is for people reading this from tty2 of the
7155 @c installation image.
7156 You are reading this documentation with an Info reader. For details on
7157 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7158 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7159 Info}. Hit @kbd{l} afterwards to come back here.
7161 Alternately, run @command{info info} in another tty to keep the manual
7167 * Limitations:: What you can expect.
7168 * Hardware Considerations:: Supported hardware.
7169 * USB Stick Installation:: Preparing the installation medium.
7170 * Preparing for Installation:: Networking, partitioning, etc.
7171 * Proceeding with the Installation:: The real thing.
7172 * Installing GuixSD in a VM:: GuixSD playground.
7173 * Building the Installation Image:: How this comes to be.
7177 @subsection Limitations
7179 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7180 not production-ready. It may contain bugs and lack important
7181 features. Thus, if you are looking for a stable production system that
7182 respects your freedom as a computer user, a good solution at this point
7183 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7184 the more established GNU/Linux distributions}. We hope you can soon switch
7185 to the GuixSD without fear, of course. In the meantime, you can
7186 also keep using your distribution and try out the package manager on top
7187 of it (@pxref{Installation}).
7189 Before you proceed with the installation, be aware of the following
7190 noteworthy limitations applicable to version @value{VERSION}:
7194 The installation process does not include a graphical user interface and
7195 requires familiarity with GNU/Linux (see the following subsections to
7196 get a feel of what that means.)
7199 Support for the Logical Volume Manager (LVM) is missing.
7202 Few system services are currently supported out-of-the-box
7206 More than 5,000 packages are available, but you may
7207 occasionally find that a useful package is missing.
7210 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
7211 as well as a number of X11 window managers. However, some graphical
7212 applications may be missing, as well as KDE.
7215 You have been warned! But more than a disclaimer, this is an invitation
7216 to report issues (and success stories!), and to join us in improving it.
7217 @xref{Contributing}, for more info.
7220 @node Hardware Considerations
7221 @subsection Hardware Considerations
7223 @cindex hardware support on GuixSD
7224 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7225 builds around the kernel Linux-libre, which means that only hardware for
7226 which free software drivers and firmware exist is supported. Nowadays,
7227 a wide range of off-the-shelf hardware is supported on
7228 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7229 Ethernet controllers. Unfortunately, there are still areas where
7230 hardware vendors deny users control over their own computing, and such
7231 hardware is not supported on GuixSD.
7233 @cindex WiFi, hardware support
7234 One of the main areas where free drivers or firmware are lacking is WiFi
7235 devices. WiFi devices known to work include those using Atheros chips
7236 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7237 driver, and those using Broadcom/AirForce chips (BCM43xx with
7238 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7239 Linux-libre driver. Free firmware exists for both and is available
7240 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7241 (@pxref{operating-system Reference, @code{firmware}}).
7243 @cindex RYF, Respects Your Freedom
7244 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7245 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7246 certification program for hardware products that respect your freedom
7247 and your privacy and ensure that you have control over your device. We
7248 encourage you to check the list of RYF-certified devices.
7250 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7251 web site. It contains a catalog of hardware devices with information
7252 about their support in GNU/Linux.
7255 @node USB Stick Installation
7256 @subsection USB Stick Installation
7258 An installation image for USB sticks can be downloaded from
7259 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7260 where @var{system} is one of:
7264 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7267 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7270 @c start duplication of authentication part from ``Binary Installation''
7271 Make sure to download the associated @file{.sig} file and to verify the
7272 authenticity of the image against it, along these lines:
7275 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7276 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7279 If that command fails because you do not have the required public key,
7280 then run this command to import it:
7283 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7287 and rerun the @code{gpg --verify} command.
7290 This image contains a single partition with the tools necessary for an
7291 installation. It is meant to be copied @emph{as is} to a large-enough
7294 To copy the image to a USB stick, follow these steps:
7298 Decompress the image using the @command{xz} command:
7301 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7305 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7306 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7307 copy the image with:
7310 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7313 Access to @file{/dev/sdX} usually requires root privileges.
7316 Once this is done, you should be able to reboot the system and boot from
7317 the USB stick. The latter usually requires you to get in the BIOS' boot
7318 menu, where you can choose to boot from the USB stick.
7320 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7321 GuixSD in a virtual machine (VM).
7323 @node Preparing for Installation
7324 @subsection Preparing for Installation
7326 Once you have successfully booted the image on the USB stick, you should
7327 end up with a root prompt. Several console TTYs are configured and can
7328 be used to run commands as root. TTY2 shows this documentation,
7329 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7330 Stand-alone GNU Info}). The installation system runs the GPM mouse
7331 daemon, which allows you to select text with the left mouse button and
7332 to paste it with the middle button.
7335 Installation requires access to the Internet so that any missing
7336 dependencies of your system configuration can be downloaded. See the
7337 ``Networking'' section below.
7340 The installation system includes many common tools needed for this task.
7341 But it is also a full-blown GuixSD system, which means that you can
7342 install additional packages, should you need it, using @command{guix
7343 package} (@pxref{Invoking guix package}).
7345 @subsubsection Keyboard Layout
7347 @cindex keyboard layout
7348 The installation image uses the US qwerty keyboard layout. If you want
7349 to change it, you can use the @command{loadkeys} command. For example,
7350 the following command selects the Dvorak keyboard layout:
7356 See the files under @file{/run/current-system/profile/share/keymaps} for
7357 a list of available keyboard layouts. Run @command{man loadkeys} for
7360 @subsubsection Networking
7362 Run the following command see what your network interfaces are called:
7369 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7375 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7376 Wired interfaces have a name starting with @samp{e}; for example, the
7377 interface corresponding to the first on-board Ethernet controller is
7378 called @samp{eno1}. Wireless interfaces have a name starting with
7379 @samp{w}, like @samp{w1p2s0}.
7382 @item Wired connection
7383 To configure a wired network run the following command, substituting
7384 @var{interface} with the name of the wired interface you want to use.
7387 ifconfig @var{interface} up
7390 @item Wireless connection
7393 To configure wireless networking, you can create a configuration file
7394 for the @command{wpa_supplicant} configuration tool (its location is not
7395 important) using one of the available text editors such as
7399 zile wpa_supplicant.conf
7402 As an example, the following stanza can go to this file and will work
7403 for many wireless networks, provided you give the actual SSID and
7404 passphrase for the network you are connecting to:
7408 ssid="@var{my-ssid}"
7410 psk="the network's secret passphrase"
7414 Start the wireless service and run it in the background with the
7415 following command (substitute @var{interface} with the name of the
7416 network interface you want to use):
7419 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7422 Run @command{man wpa_supplicant} for more information.
7426 At this point, you need to acquire an IP address. On a network where IP
7427 addresses are automatically assigned @i{via} DHCP, you can run:
7430 dhclient -v @var{interface}
7433 Try to ping a server to see if networking is up and running:
7439 Setting up network access is almost always a requirement because the
7440 image does not contain all the software and tools that may be needed.
7442 @subsubsection Disk Partitioning
7444 Unless this has already been done, the next step is to partition, and
7445 then format the target partition(s).
7447 The installation image includes several partitioning tools, including
7448 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7449 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7450 the partition layout you want:
7456 If your disk uses the GUID Partition Table (GPT) format and you plan to
7457 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7458 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7461 Once you are done partitioning the target hard disk drive, you have to
7462 create a file system on the relevant partition(s)@footnote{Currently
7463 GuixSD only supports ext4 and btrfs file systems. In particular, code
7464 that reads partition UUIDs and labels only works for these file system
7467 Preferably, assign partitions a label so that you can easily and
7468 reliably refer to them in @code{file-system} declarations (@pxref{File
7469 Systems}). This is typically done using the @code{-L} option of
7470 @command{mkfs.ext4} and related commands. So, assuming the target root
7471 partition lives at @file{/dev/sda1}, a file system with the label
7472 @code{my-root} can be created with:
7475 mkfs.ext4 -L my-root /dev/sda1
7478 @cindex encrypted disk
7479 If you are instead planning to encrypt the root partition, you can use
7480 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7481 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7482 @code{man cryptsetup}} for more information.) Assuming you want to
7483 store the root partition on @file{/dev/sda1}, the command sequence would
7484 be along these lines:
7487 cryptsetup luksFormat /dev/sda1
7488 cryptsetup open --type luks /dev/sda1 my-partition
7489 mkfs.ext4 -L my-root /dev/mapper/my-partition
7492 Once that is done, mount the target root partition under @file{/mnt}
7493 with a command like (again, assuming @code{my-root} is the label of the
7497 mount LABEL=my-root /mnt
7500 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7501 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7502 sure to initialize them with @command{mkswap}. Assuming you have one
7503 swap partition on @file{/dev/sda2}, you would run:
7510 Alternatively, you may use a swap file. For example, assuming that in
7511 the new system you want to use the file @file{/swapfile} as a swap file,
7512 you would run@footnote{This example will work for many types of file
7513 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7514 btrfs), the required steps may be different. For details, see the
7515 manual pages for @command{mkswap} and @command{swapon}.}:
7518 # This is 10 GiB of swap space. Adjust "count" to change the size.
7519 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7520 # For security, make the file readable and writable only by root.
7521 chmod 600 /mnt/swapfile
7522 mkswap /mnt/swapfile
7523 swapon /mnt/swapfile
7526 Note that if you have encrypted the root partition and created a swap
7527 file in its file system as described above, then the encryption also
7528 protects the swap file, just like any other file in that file system.
7530 @node Proceeding with the Installation
7531 @subsection Proceeding with the Installation
7533 With the target partitions ready and the target root mounted on
7534 @file{/mnt}, we're ready to go. First, run:
7537 herd start cow-store /mnt
7540 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7541 during the installation phase are written to the target disk on @file{/mnt}
7542 rather than kept in memory. This is necessary because the first phase of
7543 the @command{guix system init} command (see below) entails downloads or
7544 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7546 Next, you have to edit a file and
7547 provide the declaration of the operating system to be installed. To
7548 that end, the installation system comes with three text editors: GNU nano
7549 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7550 nvi (a clone of the original BSD @command{vi} editor).
7551 We strongly recommend storing that file on the target root file system, say,
7552 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7553 configuration file once you have rebooted into the newly-installed system.
7555 @xref{Using the Configuration System}, for an overview of the
7556 configuration file. The example configurations discussed in that
7557 section are available under @file{/etc/configuration} in the
7558 installation image. Thus, to get started with a system configuration
7559 providing a graphical display server (a ``desktop'' system), you can run
7560 something along these lines:
7564 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7565 # zile /mnt/etc/config.scm
7568 You should pay attention to what your configuration file contains, and
7573 Make sure the @code{grub-configuration} form refers to the device you
7574 want to install GRUB on.
7577 Be sure that your partition labels match the value of their respective
7578 @code{device} fields in your @code{file-system} configuration, assuming
7579 your @code{file-system} configuration sets the value of @code{title} to
7583 If there are encrypted or RAID partitions, make sure to add a
7584 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7587 Once you are done preparing the configuration file, the new system must
7588 be initialized (remember that the target root file system is mounted
7592 guix system init /mnt/etc/config.scm /mnt
7596 This copies all the necessary files and installs GRUB on
7597 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7598 more information, @pxref{Invoking guix system}. This command may trigger
7599 downloads or builds of missing packages, which can take some time.
7601 Once that command has completed---and hopefully succeeded!---you can run
7602 @command{reboot} and boot into the new system. The @code{root} password
7603 in the new system is initially empty; other users' passwords need to be
7604 initialized by running the @command{passwd} command as @code{root},
7605 unless your configuration specifies otherwise
7606 (@pxref{user-account-password, user account passwords}).
7608 @cindex upgrading GuixSD
7609 From then on, you can update GuixSD whenever you want by running
7610 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7611 then running @command{guix system reconfigure} to build a new system
7612 generation with the latest packages and services (@pxref{Invoking guix
7613 system}). We recommend doing that regularly so that your system
7614 includes the latest security updates (@pxref{Security Updates}).
7616 Join us on @code{#guix} on the Freenode IRC network or on
7617 @file{guix-devel@@gnu.org} to share your experience---good or not so
7620 @node Installing GuixSD in a VM
7621 @subsection Installing GuixSD in a Virtual Machine
7623 @cindex virtual machine, GuixSD installation
7624 If you'd like to install GuixSD in a virtual machine (VM) rather than on
7625 your beloved machine, this section is for you.
7627 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7628 disk image, follow these steps:
7632 First, retrieve and decompress the GuixSD installation image as
7633 described previously (@pxref{USB Stick Installation}).
7636 Create a disk image that will hold the installed system. To make a
7637 qcow2-formatted disk image, use the @command{qemu-img} command:
7640 qemu-img create -f qcow2 guixsd.img 5G
7643 This will create a 5GB file.
7646 Boot the USB installation image in an VM:
7649 qemu-system-x86_64 -m 1024 -smp 1 \
7650 -net user -net nic,model=virtio -boot menu=on \
7651 -drive file=guixsd.img \
7652 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7655 In the VM console, quickly press the @kbd{F12} key to enter the boot
7656 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7660 You're now root in the VM, proceed with the installation process.
7661 @xref{Preparing for Installation}, and follow the instructions.
7664 Once installation is complete, you can boot the system that's on your
7665 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7668 @node Building the Installation Image
7669 @subsection Building the Installation Image
7671 @cindex installation image
7672 The installation image described above was built using the @command{guix
7673 system} command, specifically:
7675 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7677 guix system disk-image --image-size=1G gnu/system/install.scm
7680 Have a look at @file{gnu/system/install.scm} in the source tree,
7681 and see also @ref{Invoking guix system} for more information
7682 about the installation image.
7684 @node System Configuration
7685 @section System Configuration
7687 @cindex system configuration
7688 The Guix System Distribution supports a consistent whole-system configuration
7689 mechanism. By that we mean that all aspects of the global system
7690 configuration---such as the available system services, timezone and
7691 locale settings, user accounts---are declared in a single place. Such
7692 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7694 One of the advantages of putting all the system configuration under the
7695 control of Guix is that it supports transactional system upgrades, and
7696 makes it possible to roll back to a previous system instantiation,
7697 should something go wrong with the new one (@pxref{Features}). Another
7698 advantage is that it makes it easy to replicate the exact same configuration
7699 across different machines, or at different points in time, without
7700 having to resort to additional administration tools layered on top of
7701 the own tools of the system.
7702 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7704 This section describes this mechanism. First we focus on the system
7705 administrator's viewpoint---explaining how the system is configured and
7706 instantiated. Then we show how this mechanism can be extended, for
7707 instance to support new system services.
7710 * Using the Configuration System:: Customizing your GNU system.
7711 * operating-system Reference:: Detail of operating-system declarations.
7712 * File Systems:: Configuring file system mounts.
7713 * Mapped Devices:: Block device extra processing.
7714 * User Accounts:: Specifying user accounts.
7715 * Locales:: Language and cultural convention settings.
7716 * Services:: Specifying system services.
7717 * Setuid Programs:: Programs running with root privileges.
7718 * X.509 Certificates:: Authenticating HTTPS servers.
7719 * Name Service Switch:: Configuring libc's name service switch.
7720 * Initial RAM Disk:: Linux-Libre bootstrapping.
7721 * GRUB Configuration:: Configuring the boot loader.
7722 * Invoking guix system:: Instantiating a system configuration.
7723 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7724 * Defining Services:: Adding new service definitions.
7727 @node Using the Configuration System
7728 @subsection Using the Configuration System
7730 The operating system is configured by providing an
7731 @code{operating-system} declaration in a file that can then be passed to
7732 the @command{guix system} command (@pxref{Invoking guix system}). A
7733 simple setup, with the default system services, the default Linux-Libre
7734 kernel, initial RAM disk, and boot loader looks like this:
7736 @findex operating-system
7738 @include os-config-bare-bones.texi
7741 This example should be self-describing. Some of the fields defined
7742 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7743 Others, such as @code{packages} and @code{services}, can be omitted, in
7744 which case they get a default value.
7746 Below we discuss the effect of some of the most important fields
7747 (@pxref{operating-system Reference}, for details about all the available
7748 fields), and how to @dfn{instantiate} the operating system using
7749 @command{guix system}.
7751 @unnumberedsubsubsec Globally-Visible Packages
7753 @vindex %base-packages
7754 The @code{packages} field lists packages that will be globally visible
7755 on the system, for all user accounts---i.e., in every user's @code{PATH}
7756 environment variable---in addition to the per-user profiles
7757 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7758 provides all the tools one would expect for basic user and administrator
7759 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7760 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7761 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7762 packages admin)} module (@pxref{Package Modules}).
7764 @findex specification->package
7765 Referring to packages by variable name, like @var{tcpdump} above, has
7766 the advantage of being unambiguous; it also allows typos and such to be
7767 diagnosed right away as ``unbound variables''. The downside is that one
7768 needs to know which module defines which package, and to augment the
7769 @code{use-package-modules} line accordingly. To avoid that, one can use
7770 the @code{specification->package} procedure of the @code{(gnu packages)}
7771 module, which returns the best package for a given name or name and
7775 (use-modules (gnu packages))
7779 (packages (append (map specification->package
7780 '("tcpdump" "htop" "gnupg@@2.0"))
7784 @unnumberedsubsubsec System Services
7787 @vindex %base-services
7788 The @code{services} field lists @dfn{system services} to be made
7789 available when the system starts (@pxref{Services}).
7790 The @code{operating-system} declaration above specifies that, in
7791 addition to the basic services, we want the @command{lshd} secure shell
7792 daemon listening on port 2222 (@pxref{Networking Services,
7793 @code{lsh-service}}). Under the hood,
7794 @code{lsh-service} arranges so that @code{lshd} is started with the
7795 right command-line options, possibly with supporting configuration files
7796 generated as needed (@pxref{Defining Services}).
7798 @cindex customization, of services
7799 @findex modify-services
7800 Occasionally, instead of using the base services as is, you will want to
7801 customize them. To do this, use @code{modify-services} (@pxref{Service
7802 Reference, @code{modify-services}}) to modify the list.
7804 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7805 (the console log-in) in the @var{%base-services} list (@pxref{Base
7806 Services, @code{%base-services}}). To do that, you can write the
7807 following in your operating system declaration:
7810 (define %my-services
7811 ;; My very own list of services.
7812 (modify-services %base-services
7813 (guix-service-type config =>
7816 (use-substitutes? #f)
7817 (extra-options '("--gc-keep-derivations"))))
7818 (mingetty-service-type config =>
7819 (mingetty-configuration
7820 (inherit config)))))
7824 (services %my-services))
7827 This changes the configuration---i.e., the service parameters---of the
7828 @code{guix-service-type} instance, and that of all the
7829 @code{mingetty-service-type} instances in the @var{%base-services} list.
7830 Observe how this is accomplished: first, we arrange for the original
7831 configuration to be bound to the identifier @code{config} in the
7832 @var{body}, and then we write the @var{body} so that it evaluates to the
7833 desired configuration. In particular, notice how we use @code{inherit}
7834 to create a new configuration which has the same values as the old
7835 configuration, but with a few modifications.
7837 @cindex encrypted disk
7838 The configuration for a typical ``desktop'' usage, with an encrypted
7839 root partition, the X11 display
7840 server, GNOME and Xfce (users can choose which of these desktop
7841 environments to use at the log-in screen by pressing @kbd{F1}), network
7842 management, power management, and more, would look like this:
7845 @include os-config-desktop.texi
7848 A graphical environment with a choice of lightweight window managers
7849 instead of full-blown desktop environments would look like this:
7852 @include os-config-lightweight-desktop.texi
7855 @xref{Desktop Services}, for the exact list of services provided by
7856 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7857 information about the @code{nss-certs} package that is used here.
7859 Again, @var{%desktop-services} is just a list of service objects. If
7860 you want to remove services from there, you can do so using the
7861 procedures for list filtering (@pxref{SRFI-1 Filtering and
7862 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7863 following expression returns a list that contains all the services in
7864 @var{%desktop-services} minus the Avahi service:
7867 (remove (lambda (service)
7868 (eq? (service-kind service) avahi-service-type))
7872 @unnumberedsubsubsec Instantiating the System
7874 Assuming the @code{operating-system} declaration
7875 is stored in the @file{my-system-config.scm}
7876 file, the @command{guix system reconfigure my-system-config.scm} command
7877 instantiates that configuration, and makes it the default GRUB boot
7878 entry (@pxref{Invoking guix system}).
7880 The normal way to change the system configuration is by updating this
7881 file and re-running @command{guix system reconfigure}. One should never
7882 have to touch files in @file{/etc} or to run commands that modify the
7883 system state such as @command{useradd} or @command{grub-install}. In
7884 fact, you must avoid that since that would not only void your warranty
7885 but also prevent you from rolling back to previous versions of your
7886 system, should you ever need to.
7888 @cindex roll-back, of the operating system
7889 Speaking of roll-back, each time you run @command{guix system
7890 reconfigure}, a new @dfn{generation} of the system is created---without
7891 modifying or deleting previous generations. Old system generations get
7892 an entry in the GRUB boot menu, allowing you to boot them in case
7893 something went wrong with the latest generation. Reassuring, no? The
7894 @command{guix system list-generations} command lists the system
7895 generations available on disk. It is also possible to roll back the
7896 system via the commands @command{guix system roll-back} and
7897 @command{guix system switch-generation}.
7899 Although the command @command{guix system reconfigure} will not modify
7900 previous generations, must take care when the current generation is not
7901 the latest (e.g., after invoking @command{guix system roll-back}), since
7902 the operation might overwrite a later generation (@pxref{Invoking guix
7905 @unnumberedsubsubsec The Programming Interface
7907 At the Scheme level, the bulk of an @code{operating-system} declaration
7908 is instantiated with the following monadic procedure (@pxref{The Store
7911 @deffn {Monadic Procedure} operating-system-derivation os
7912 Return a derivation that builds @var{os}, an @code{operating-system}
7913 object (@pxref{Derivations}).
7915 The output of the derivation is a single directory that refers to all
7916 the packages, configuration files, and other supporting files needed to
7917 instantiate @var{os}.
7920 This procedure is provided by the @code{(gnu system)} module. Along
7921 with @code{(gnu services)} (@pxref{Services}), this module contains the
7922 guts of GuixSD. Make sure to visit it!
7925 @node operating-system Reference
7926 @subsection @code{operating-system} Reference
7928 This section summarizes all the options available in
7929 @code{operating-system} declarations (@pxref{Using the Configuration
7932 @deftp {Data Type} operating-system
7933 This is the data type representing an operating system configuration.
7934 By that, we mean all the global system configuration, not per-user
7935 configuration (@pxref{Using the Configuration System}).
7938 @item @code{kernel} (default: @var{linux-libre})
7939 The package object of the operating system kernel to use@footnote{Currently
7940 only the Linux-libre kernel is supported. In the future, it will be
7941 possible to use the GNU@tie{}Hurd.}.
7943 @item @code{kernel-arguments} (default: @code{'()})
7944 List of strings or gexps representing additional arguments to pass on
7945 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7947 @item @code{bootloader}
7948 The system bootloader configuration object. @xref{GRUB Configuration}.
7950 @item @code{initrd} (default: @code{base-initrd})
7952 @cindex initial RAM disk
7953 A two-argument monadic procedure that returns an initial RAM disk for
7954 the Linux kernel. @xref{Initial RAM Disk}.
7956 @item @code{firmware} (default: @var{%base-firmware})
7958 List of firmware packages loadable by the operating system kernel.
7960 The default includes firmware needed for Atheros- and Broadcom-based
7961 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
7962 respectively). @xref{Hardware Considerations}, for more info on
7965 @item @code{host-name}
7968 @item @code{hosts-file}
7970 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
7971 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
7972 Reference Manual}). The default is a file with entries for
7973 @code{localhost} and @var{host-name}.
7975 @item @code{mapped-devices} (default: @code{'()})
7976 A list of mapped devices. @xref{Mapped Devices}.
7978 @item @code{file-systems}
7979 A list of file systems. @xref{File Systems}.
7981 @item @code{swap-devices} (default: @code{'()})
7982 @cindex swap devices
7983 A list of strings identifying devices or files to be used for ``swap
7984 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
7985 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
7986 It is possible to specify a swap file in a file system on a mapped
7987 device, provided that the necessary device mapping and file system are
7988 also specified. @xref{Mapped Devices} and @ref{File Systems}.
7990 @item @code{users} (default: @code{%base-user-accounts})
7991 @itemx @code{groups} (default: @var{%base-groups})
7992 List of user accounts and groups. @xref{User Accounts}.
7994 @item @code{skeletons} (default: @code{(default-skeletons)})
7995 A list target file name/file-like object tuples (@pxref{G-Expressions,
7996 file-like objects}). These are the skeleton files that will be added to
7997 the home directory of newly-created user accounts.
7999 For instance, a valid value may look like this:
8002 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8003 (".guile" ,(plain-file "guile"
8004 "(use-modules (ice-9 readline))
8005 (activate-readline)")))
8008 @item @code{issue} (default: @var{%default-issue})
8009 A string denoting the contents of the @file{/etc/issue} file, which is
8010 displayed when users log in on a text console.
8012 @item @code{packages} (default: @var{%base-packages})
8013 The set of packages installed in the global profile, which is accessible
8014 at @file{/run/current-system/profile}.
8016 The default set includes core utilities and it is good practice to
8017 install non-core utilities in user profiles (@pxref{Invoking guix
8020 @item @code{timezone}
8021 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8023 You can run the @command{tzselect} command to find out which timezone
8024 string corresponds to your region. Choosing an invalid timezone name
8025 causes @command{guix system} to fail.
8027 @item @code{locale} (default: @code{"en_US.utf8"})
8028 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8029 Library Reference Manual}). @xref{Locales}, for more information.
8031 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8032 The list of locale definitions to be compiled and that may be used at
8033 run time. @xref{Locales}.
8035 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8036 The list of GNU@tie{}libc packages whose locale data and tools are used
8037 to build the locale definitions. @xref{Locales}, for compatibility
8038 considerations that justify this option.
8040 @item @code{name-service-switch} (default: @var{%default-nss})
8041 Configuration of the libc name service switch (NSS)---a
8042 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8045 @item @code{services} (default: @var{%base-services})
8046 A list of service objects denoting system services. @xref{Services}.
8048 @item @code{pam-services} (default: @code{(base-pam-services)})
8050 @cindex pluggable authentication modules
8051 Linux @dfn{pluggable authentication module} (PAM) services.
8052 @c FIXME: Add xref to PAM services section.
8054 @item @code{setuid-programs} (default: @var{%setuid-programs})
8055 List of string-valued G-expressions denoting setuid programs.
8056 @xref{Setuid Programs}.
8058 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8059 @cindex sudoers file
8060 The contents of the @file{/etc/sudoers} file as a file-like object
8061 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8063 This file specifies which users can use the @command{sudo} command, what
8064 they are allowed to do, and what privileges they may gain. The default
8065 is that only @code{root} and members of the @code{wheel} group may use
8072 @subsection File Systems
8074 The list of file systems to be mounted is specified in the
8075 @code{file-systems} field of the operating system declaration
8076 (@pxref{Using the Configuration System}). Each file system is declared
8077 using the @code{file-system} form, like this:
8081 (mount-point "/home")
8082 (device "/dev/sda3")
8086 As usual, some of the fields are mandatory---those shown in the example
8087 above---while others can be omitted. These are described below.
8089 @deftp {Data Type} file-system
8090 Objects of this type represent file systems to be mounted. They
8091 contain the following members:
8095 This is a string specifying the type of the file system---e.g.,
8098 @item @code{mount-point}
8099 This designates the place where the file system is to be mounted.
8102 This names the ``source'' of the file system. By default it is the name
8103 of a node under @file{/dev}, but its meaning depends on the @code{title}
8104 field described below.
8106 @item @code{title} (default: @code{'device})
8107 This is a symbol that specifies how the @code{device} field is to be
8110 When it is the symbol @code{device}, then the @code{device} field is
8111 interpreted as a file name; when it is @code{label}, then @code{device}
8112 is interpreted as a partition label name; when it is @code{uuid},
8113 @code{device} is interpreted as a partition unique identifier (UUID).
8115 UUIDs may be converted from their string representation (as shown by the
8116 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8117 @code{uuid} form expects 16-byte UUIDs as defined in
8118 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8119 form of UUID used by the ext2 family of file systems and others, but it
8120 is different from ``UUIDs'' found in FAT file systems, for instance.},
8125 (mount-point "/home")
8128 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8131 The @code{label} and @code{uuid} options offer a way to refer to disk
8132 partitions without having to hard-code their actual device
8133 name@footnote{Note that, while it is tempting to use
8134 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8135 result, this is not recommended: These special device nodes are created
8136 by the udev daemon and may be unavailable at the time the device is
8139 However, when the source of a file system is a mapped device (@pxref{Mapped
8140 Devices}), its @code{device} field @emph{must} refer to the mapped
8141 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8142 @code{title} must be set to @code{'device}. This is required so that
8143 the system knows that mounting the file system depends on having the
8144 corresponding device mapping established.
8146 @item @code{flags} (default: @code{'()})
8147 This is a list of symbols denoting mount flags. Recognized flags
8148 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8149 access to special files), @code{no-suid} (ignore setuid and setgid
8150 bits), and @code{no-exec} (disallow program execution.)
8152 @item @code{options} (default: @code{#f})
8153 This is either @code{#f}, or a string denoting mount options.
8155 @item @code{mount?} (default: @code{#t})
8156 This value indicates whether to automatically mount the file system when
8157 the system is brought up. When set to @code{#f}, the file system gets
8158 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8159 is not automatically mounted.
8161 @item @code{needed-for-boot?} (default: @code{#f})
8162 This Boolean value indicates whether the file system is needed when
8163 booting. If that is true, then the file system is mounted when the
8164 initial RAM disk (initrd) is loaded. This is always the case, for
8165 instance, for the root file system.
8167 @item @code{check?} (default: @code{#t})
8168 This Boolean indicates whether the file system needs to be checked for
8169 errors before being mounted.
8171 @item @code{create-mount-point?} (default: @code{#f})
8172 When true, the mount point is created if it does not exist yet.
8174 @item @code{dependencies} (default: @code{'()})
8175 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8176 representing file systems that must be mounted or mapped devices that
8177 must be opened before (and unmounted or closed after) this one.
8179 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8180 a dependency of @file{/sys/fs/cgroup/cpu} and
8181 @file{/sys/fs/cgroup/memory}.
8183 Another example is a file system that depends on a mapped device, for
8184 example for an encrypted partition (@pxref{Mapped Devices}).
8188 The @code{(gnu system file-systems)} exports the following useful
8191 @defvr {Scheme Variable} %base-file-systems
8192 These are essential file systems that are required on normal systems,
8193 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8194 below.) Operating system declarations should always contain at least
8198 @defvr {Scheme Variable} %pseudo-terminal-file-system
8199 This is the file system to be mounted as @file{/dev/pts}. It supports
8200 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8201 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8202 Manual}). Pseudo-terminals are used by terminal emulators such as
8206 @defvr {Scheme Variable} %shared-memory-file-system
8207 This file system is mounted as @file{/dev/shm} and is used to support
8208 memory sharing across processes (@pxref{Memory-mapped I/O,
8209 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8212 @defvr {Scheme Variable} %immutable-store
8213 This file system performs a read-only ``bind mount'' of
8214 @file{/gnu/store}, making it read-only for all the users including
8215 @code{root}. This prevents against accidental modification by software
8216 running as @code{root} or by system administrators.
8218 The daemon itself is still able to write to the store: it remounts it
8219 read-write in its own ``name space.''
8222 @defvr {Scheme Variable} %binary-format-file-system
8223 The @code{binfmt_misc} file system, which allows handling of arbitrary
8224 executable file types to be delegated to user space. This requires the
8225 @code{binfmt.ko} kernel module to be loaded.
8228 @defvr {Scheme Variable} %fuse-control-file-system
8229 The @code{fusectl} file system, which allows unprivileged users to mount
8230 and unmount user-space FUSE file systems. This requires the
8231 @code{fuse.ko} kernel module to be loaded.
8234 @node Mapped Devices
8235 @subsection Mapped Devices
8237 @cindex device mapping
8238 @cindex mapped devices
8239 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8240 such as a hard disk partition, can be @dfn{mapped} into another device,
8241 usually in @code{/dev/mapper/},
8242 with additional processing over the data that flows through
8243 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8244 concept of a ``mapped device'' and that of a file system: both boil down
8245 to @emph{translating} input/output operations made on a file to
8246 operations on its backing store. Thus, the Hurd implements mapped
8247 devices, like file systems, using the generic @dfn{translator} mechanism
8248 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8249 typical example is encryption device mapping: all writes to the mapped
8250 device are encrypted, and all reads are deciphered, transparently.
8251 Guix extends this notion by considering any device or set of devices that
8252 are @dfn{transformed} in some way to create a new device; for instance,
8253 RAID devices are obtained by @dfn{assembling} several other devices, such
8254 as hard disks or partitions, into a new one that behaves as one partition.
8255 Other examples, not yet implemented, are LVM logical volumes.
8257 Mapped devices are declared using the @code{mapped-device} form,
8258 defined as follows; for examples, see below.
8260 @deftp {Data Type} mapped-device
8261 Objects of this type represent device mappings that will be made when
8262 the system boots up.
8266 This is either a string specifying the name of the block device to be mapped,
8267 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8268 need to be assembled for creating a new one.
8271 This string specifies the name of the resulting mapped device. For
8272 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8273 specifying @code{"my-partition"} leads to the creation of
8274 the @code{"/dev/mapper/my-partition"} device.
8275 For RAID devices of type @code{raid-device-mapping}, the full device name
8276 such as @code{"/dev/md0"} needs to be given.
8279 This must be a @code{mapped-device-kind} object, which specifies how
8280 @var{source} is mapped to @var{target}.
8284 @defvr {Scheme Variable} luks-device-mapping
8285 This defines LUKS block device encryption using the @command{cryptsetup}
8286 command from the package with the same name. It relies on the
8287 @code{dm-crypt} Linux kernel module.
8290 @defvr {Scheme Variable} raid-device-mapping
8291 This defines a RAID device, which is assembled using the @code{mdadm}
8292 command from the package with the same name. It requires a Linux kernel
8293 module for the appropriate RAID level to be loaded, such as @code{raid456}
8294 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8297 @cindex disk encryption
8299 The following example specifies a mapping from @file{/dev/sda3} to
8300 @file{/dev/mapper/home} using LUKS---the
8301 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8302 standard mechanism for disk encryption.
8303 The @file{/dev/mapper/home}
8304 device can then be used as the @code{device} of a @code{file-system}
8305 declaration (@pxref{File Systems}).
8309 (source "/dev/sda3")
8311 (type luks-device-mapping))
8314 Alternatively, to become independent of device numbering, one may obtain
8315 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8319 cryptsetup luksUUID /dev/sda3
8322 and use it as follows:
8326 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8328 (type luks-device-mapping))
8331 @cindex swap encryption
8332 It is also desirable to encrypt swap space, since swap space may contain
8333 sensitive data. One way to accomplish that is to use a swap file in a
8334 file system on a device mapped via LUKS encryption. In this way, the
8335 swap file is encrypted because the entire device is encrypted.
8336 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8338 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8339 may be declared as follows:
8343 (source (list "/dev/sda1" "/dev/sdb1"))
8345 (type raid-device-mapping))
8348 The @file{/dev/md0} device can then be used as the @code{device} of a
8349 @code{file-system} declaration (@pxref{File Systems}).
8350 Note that the RAID level need not be given; it is chosen during the
8351 initial creation and formatting of the RAID device and is determined
8352 automatically later.
8356 @subsection User Accounts
8360 @cindex user accounts
8361 User accounts and groups are entirely managed through the
8362 @code{operating-system} declaration. They are specified with the
8363 @code{user-account} and @code{user-group} forms:
8369 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8371 "video" ;video devices such as webcams
8372 "cdrom")) ;the good ol' CD-ROM
8373 (comment "Bob's sister")
8374 (home-directory "/home/alice"))
8377 When booting or upon completion of @command{guix system reconfigure},
8378 the system ensures that only the user accounts and groups specified in
8379 the @code{operating-system} declaration exist, and with the specified
8380 properties. Thus, account or group creations or modifications made by
8381 directly invoking commands such as @command{useradd} are lost upon
8382 reconfiguration or reboot. This ensures that the system remains exactly
8385 @deftp {Data Type} user-account
8386 Objects of this type represent user accounts. The following members may
8391 The name of the user account.
8395 This is the name (a string) or identifier (a number) of the user group
8396 this account belongs to.
8398 @item @code{supplementary-groups} (default: @code{'()})
8399 Optionally, this can be defined as a list of group names that this
8402 @item @code{uid} (default: @code{#f})
8403 This is the user ID for this account (a number), or @code{#f}. In the
8404 latter case, a number is automatically chosen by the system when the
8407 @item @code{comment} (default: @code{""})
8408 A comment about the account, such as the account owner's full name.
8410 @item @code{home-directory}
8411 This is the name of the home directory for the account.
8413 @item @code{create-home-directory?} (default: @code{#t})
8414 Indicates whether the home directory of this account should be created
8415 if it does not exist yet.
8417 @item @code{shell} (default: Bash)
8418 This is a G-expression denoting the file name of a program to be used as
8419 the shell (@pxref{G-Expressions}).
8421 @item @code{system?} (default: @code{#f})
8422 This Boolean value indicates whether the account is a ``system''
8423 account. System accounts are sometimes treated specially; for instance,
8424 graphical login managers do not list them.
8426 @anchor{user-account-password}
8427 @item @code{password} (default: @code{#f})
8428 You would normally leave this field to @code{#f}, initialize user
8429 passwords as @code{root} with the @command{passwd} command, and then let
8430 users change it with @command{passwd}. Passwords set with
8431 @command{passwd} are of course preserved across reboot and
8434 If you @emph{do} want to have a preset password for an account, then
8435 this field must contain the encrypted password, as a string.
8436 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8437 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8438 Manual}, for information on Guile's @code{crypt} procedure.
8444 User group declarations are even simpler:
8447 (user-group (name "students"))
8450 @deftp {Data Type} user-group
8451 This type is for, well, user groups. There are just a few fields:
8455 The name of the group.
8457 @item @code{id} (default: @code{#f})
8458 The group identifier (a number). If @code{#f}, a new number is
8459 automatically allocated when the group is created.
8461 @item @code{system?} (default: @code{#f})
8462 This Boolean value indicates whether the group is a ``system'' group.
8463 System groups have low numerical IDs.
8465 @item @code{password} (default: @code{#f})
8466 What, user groups can have a password? Well, apparently yes. Unless
8467 @code{#f}, this field specifies the password of the group.
8472 For convenience, a variable lists all the basic user groups one may
8475 @defvr {Scheme Variable} %base-groups
8476 This is the list of basic user groups that users and/or packages expect
8477 to be present on the system. This includes groups such as ``root'',
8478 ``wheel'', and ``users'', as well as groups used to control access to
8479 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8482 @defvr {Scheme Variable} %base-user-accounts
8483 This is the list of basic system accounts that programs may expect to
8484 find on a GNU/Linux system, such as the ``nobody'' account.
8486 Note that the ``root'' account is not included here. It is a
8487 special-case and is automatically added whether or not it is specified.
8494 A @dfn{locale} defines cultural conventions for a particular language
8495 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8496 Reference Manual}). Each locale has a name that typically has the form
8497 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8498 @code{fr_LU.utf8} designates the locale for the French language, with
8499 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8501 @cindex locale definition
8502 Usually, you will want to specify the default locale for the machine
8503 using the @code{locale} field of the @code{operating-system} declaration
8504 (@pxref{operating-system Reference, @code{locale}}).
8506 The selected locale is automatically added to the @dfn{locale
8507 definitions} known to the system if needed, with its codeset inferred
8508 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8509 @code{UTF-8} codeset. Additional locale definitions can be specified in
8510 the @code{locale-definitions} slot of @code{operating-system}---this is
8511 useful, for instance, if the codeset could not be inferred from the
8512 locale name. The default set of locale definitions includes some widely
8513 used locales, but not all the available locales, in order to save space.
8515 For instance, to add the North Frisian locale for Germany, the value of
8519 (cons (locale-definition
8520 (name "fy_DE.utf8") (source "fy_DE"))
8521 %default-locale-definitions)
8524 Likewise, to save space, one might want @code{locale-definitions} to
8525 list only the locales that are actually used, as in:
8528 (list (locale-definition
8529 (name "ja_JP.eucjp") (source "ja_JP")
8530 (charset "EUC-JP")))
8534 The compiled locale definitions are available at
8535 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8536 version, which is the default location where the GNU@tie{}libc provided
8537 by Guix looks for locale data. This can be overridden using the
8538 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8539 @code{LOCPATH} and locale packages}).
8541 The @code{locale-definition} form is provided by the @code{(gnu system
8542 locale)} module. Details are given below.
8544 @deftp {Data Type} locale-definition
8545 This is the data type of a locale definition.
8550 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8551 Reference Manual}, for more information on locale names.
8554 The name of the source for that locale. This is typically the
8555 @code{@var{language}_@var{territory}} part of the locale name.
8557 @item @code{charset} (default: @code{"UTF-8"})
8558 The ``character set'' or ``code set'' for that locale,
8559 @uref{http://www.iana.org/assignments/character-sets, as defined by
8565 @defvr {Scheme Variable} %default-locale-definitions
8566 A list of commonly used UTF-8 locales, used as the default
8567 value of the @code{locale-definitions} field of @code{operating-system}
8571 @cindex normalized codeset in locale names
8572 These locale definitions use the @dfn{normalized codeset} for the part
8573 that follows the dot in the name (@pxref{Using gettextized software,
8574 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8575 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8579 @subsubsection Locale Data Compatibility Considerations
8581 @cindex incompatibility, of locale data
8582 @code{operating-system} declarations provide a @code{locale-libcs} field
8583 to specify the GNU@tie{}libc packages that are used to compile locale
8584 declarations (@pxref{operating-system Reference}). ``Why would I
8585 care?'', you may ask. Well, it turns out that the binary format of
8586 locale data is occasionally incompatible from one libc version to
8589 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8590 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8591 For instance, a program linked against libc version 2.21 is unable to
8592 read locale data produced with libc 2.22; worse, that program
8593 @emph{aborts} instead of simply ignoring the incompatible locale
8594 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8595 the incompatible locale data, which is already an improvement.}.
8596 Similarly, a program linked against libc 2.22 can read most, but not
8597 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8598 data is incompatible); thus calls to @code{setlocale} may fail, but
8599 programs will not abort.
8601 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8602 choose whether and when to upgrade software in their profiles, and might
8603 be using a libc version different from the one the system administrator
8604 used to build the system-wide locale data.
8606 Fortunately, unprivileged users can also install their own locale data
8607 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8608 @code{GUIX_LOCPATH} and locale packages}).
8610 Still, it is best if the system-wide locale data at
8611 @file{/run/current-system/locale} is built for all the libc versions
8612 actually in use on the system, so that all the programs can access
8613 it---this is especially crucial on a multi-user system. To do that, the
8614 administrator can specify several libc packages in the
8615 @code{locale-libcs} field of @code{operating-system}:
8618 (use-package-modules base)
8622 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8625 This example would lead to a system containing locale definitions for
8626 both libc 2.21 and the current version of libc in
8627 @file{/run/current-system/locale}.
8631 @subsection Services
8633 @cindex system services
8634 An important part of preparing an @code{operating-system} declaration is
8635 listing @dfn{system services} and their configuration (@pxref{Using the
8636 Configuration System}). System services are typically daemons launched
8637 when the system boots, or other actions needed at that time---e.g.,
8638 configuring network access.
8640 GuixSD has a broad definition of ``service'' (@pxref{Service
8641 Composition}), but many services are managed by the GNU@tie{}Shepherd
8642 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8643 command allows you to list the available services, show their status,
8644 start and stop them, or do other specific operations (@pxref{Jump
8645 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8651 The above command, run as @code{root}, lists the currently defined
8652 services. The @command{herd doc} command shows a synopsis of the given
8657 Run libc's name service cache daemon (nscd).
8660 The @command{start}, @command{stop}, and @command{restart} sub-commands
8661 have the effect you would expect. For instance, the commands below stop
8662 the nscd service and restart the Xorg display server:
8666 Service nscd has been stopped.
8667 # herd restart xorg-server
8668 Service xorg-server has been stopped.
8669 Service xorg-server has been started.
8672 The following sections document the available services, starting with
8673 the core services, that may be used in an @code{operating-system}
8677 * Base Services:: Essential system services.
8678 * Scheduled Job Execution:: The mcron service.
8679 * Log Rotation:: The rottlog service.
8680 * Networking Services:: Network setup, SSH daemon, etc.
8681 * X Window:: Graphical display.
8682 * Printing Services:: Local and remote printer support.
8683 * Desktop Services:: D-Bus and desktop services.
8684 * Database Services:: SQL databases.
8685 * Mail Services:: IMAP, POP3, SMTP, and all that.
8686 * Messaging Services:: Messaging services.
8687 * Kerberos Services:: Kerberos services.
8688 * Web Services:: Web servers.
8689 * VPN Services:: VPN daemons.
8690 * Network File System:: NFS related services.
8691 * Continuous Integration:: The Cuirass service.
8692 * Power management Services:: The TLP tool.
8693 * Miscellaneous Services:: Other services.
8697 @subsubsection Base Services
8699 The @code{(gnu services base)} module provides definitions for the basic
8700 services that one expects from the system. The services exported by
8701 this module are listed below.
8703 @defvr {Scheme Variable} %base-services
8704 This variable contains a list of basic services (@pxref{Service Types
8705 and Services}, for more information on service objects) one would
8706 expect from the system: a login service (mingetty) on each tty, syslogd,
8707 the libc name service cache daemon (nscd), the udev device manager, and
8710 This is the default value of the @code{services} field of
8711 @code{operating-system} declarations. Usually, when customizing a
8712 system, you will want to append services to @var{%base-services}, like
8716 (cons* (avahi-service) (lsh-service) %base-services)
8720 @defvr {Scheme Variable} special-files-service-type
8721 This is the service that sets up ``special files'' such as
8722 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8724 The value associated with @code{special-files-service-type} services
8725 must be a list of tuples where the first element is the ``special file''
8726 and the second element is its target. By default it is:
8728 @cindex @file{/bin/sh}
8729 @cindex @file{sh}, in @file{/bin}
8731 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8734 @cindex @file{/usr/bin/env}
8735 @cindex @file{env}, in @file{/usr/bin}
8736 If you want to add, say, @code{/usr/bin/env} to your system, you can
8740 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8741 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8744 Since this is part of @code{%base-services}, you can use
8745 @code{modify-services} to customize the set of special files
8746 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8747 to add a special file is @i{via} the @code{extra-special-file} procedure
8751 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8752 Use @var{target} as the ``special file'' @var{file}.
8754 For example, adding the following lines to the @code{services} field of
8755 your operating system declaration leads to a @file{/usr/bin/env}
8759 (extra-special-file "/usr/bin/env"
8760 (file-append coreutils "/bin/env"))
8764 @deffn {Scheme Procedure} host-name-service @var{name}
8765 Return a service that sets the host name to @var{name}.
8768 @deffn {Scheme Procedure} login-service @var{config}
8769 Return a service to run login according to @var{config}, a
8770 @code{<login-configuration>} object, which specifies the message of the day,
8774 @deftp {Data Type} login-configuration
8775 This is the data type representing the configuration of login.
8780 @cindex message of the day
8781 A file-like object containing the ``message of the day''.
8783 @item @code{allow-empty-passwords?} (default: @code{#t})
8784 Allow empty passwords by default so that first-time users can log in when
8785 the 'root' account has just been created.
8790 @deffn {Scheme Procedure} mingetty-service @var{config}
8791 Return a service to run mingetty according to @var{config}, a
8792 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8796 @deftp {Data Type} mingetty-configuration
8797 This is the data type representing the configuration of Mingetty, which
8798 provides the default implementation of virtual console log-in.
8803 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8805 @item @code{auto-login} (default: @code{#f})
8806 When true, this field must be a string denoting the user name under
8807 which the system automatically logs in. When it is @code{#f}, a
8808 user name and password must be entered to log in.
8810 @item @code{login-program} (default: @code{#f})
8811 This must be either @code{#f}, in which case the default log-in program
8812 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8813 the name of the log-in program.
8815 @item @code{login-pause?} (default: @code{#f})
8816 When set to @code{#t} in conjunction with @var{auto-login}, the user
8817 will have to press a key before the log-in shell is launched.
8819 @item @code{mingetty} (default: @var{mingetty})
8820 The Mingetty package to use.
8825 @deffn {Scheme Procedure} agetty-service @var{config}
8826 Return a service to run agetty according to @var{config}, an
8827 @code{<agetty-configuration>} object, which specifies the tty to run,
8831 @deftp {Data Type} agetty-configuration
8832 This is the data type representing the configuration of agetty, which
8833 implements virtual and serial console log-in. See the @code{agetty(8)}
8834 man page for more information.
8839 The name of the console this agetty runs on, as a string---e.g.,
8840 @code{"ttyS0"}. This argument is mandatory.
8842 @item @code{baud-rate} (default: @code{#f})
8843 A string containing a comma-separated list of one or more baud rates, in
8846 @item @code{term} (default: @code{#f})
8847 A string containing the value used for the @code{TERM} environment
8850 @item @code{eight-bits?} (default: @code{#f})
8851 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8854 @item @code{auto-login} (default: @code{#f})
8855 When passed a login name, as a string, the specified user will be logged
8856 in automatically without prompting for their login name or password.
8858 @item @code{no-reset?} (default: @code{#f})
8859 When @code{#t}, don't reset terminal cflags (control modes).
8861 @item @code{host} (default: @code{#f})
8862 This accepts a string containing the "login_host", which will be written
8863 into the @file{/var/run/utmpx} file.
8865 @item @code{remote?} (default: @code{#f})
8866 When set to @code{#t} in conjunction with @var{host}, this will add an
8867 @code{-r} fakehost option to the command line of the login program
8868 specified in @var{login-program}.
8870 @item @code{flow-control?} (default: @code{#f})
8871 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8873 @item @code{no-issue?} (default: @code{#f})
8874 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8875 not be displayed before presenting the login prompt.
8877 @item @code{init-string} (default: @code{#f})
8878 This accepts a string that will be sent to the tty or modem before
8879 sending anything else. It can be used to initialize a modem.
8881 @item @code{no-clear?} (default: @code{#f})
8882 When set to @code{#t}, agetty will not clear the screen before showing
8885 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8886 This must be either a gexp denoting the name of a log-in program, or
8887 unset, in which case the default value is the @command{login} from the
8890 @item @code{local-line} (default: @code{#f})
8891 Control the CLOCAL line flag. This accepts one of three symbols as
8892 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8893 the default value chosen by agetty is @code{'auto}.
8895 @item @code{extract-baud?} (default: @code{#f})
8896 When set to @code{#t}, instruct agetty to try to extract the baud rate
8897 from the status messages produced by certain types of modems.
8899 @item @code{skip-login?} (default: @code{#f})
8900 When set to @code{#t}, do not prompt the user for a login name. This
8901 can be used with @var{login-program} field to use non-standard login
8904 @item @code{no-newline?} (default: @code{#f})
8905 When set to @code{#t}, do not print a newline before printing the
8906 @file{/etc/issue} file.
8908 @c Is this dangerous only when used with login-program, or always?
8909 @item @code{login-options} (default: @code{#f})
8910 This option accepts a string containing options that are passed to the
8911 login program. When used with the @var{login-program}, be aware that a
8912 malicious user could try to enter a login name containing embedded
8913 options that could be parsed by the login program.
8915 @item @code{login-pause} (default: @code{#f})
8916 When set to @code{#t}, wait for any key before showing the login prompt.
8917 This can be used in conjunction with @var{auto-login} to save memory by
8918 lazily spawning shells.
8920 @item @code{chroot} (default: @code{#f})
8921 Change root to the specified directory. This option accepts a directory
8924 @item @code{hangup?} (default: @code{#f})
8925 Use the Linux system call @code{vhangup} to do a virtual hangup of the
8928 @item @code{keep-baud?} (default: @code{#f})
8929 When set to @code{#t}, try to keep the existing baud rate. The baud
8930 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
8933 @item @code{timeout} (default: @code{#f})
8934 When set to an integer value, terminate if no user name could be read
8935 within @var{timeout} seconds.
8937 @item @code{detect-case?} (default: @code{#f})
8938 When set to @code{#t}, turn on support for detecting an uppercase-only
8939 terminal. This setting will detect a login name containing only
8940 uppercase letters as indicating an uppercase-only terminal and turn on
8941 some upper-to-lower case conversions. Note that this will not support
8944 @item @code{wait-cr?} (default: @code{#f})
8945 When set to @code{#t}, wait for the user or modem to send a
8946 carriage-return or linefeed character before displaying
8947 @file{/etc/issue} or login prompt. This is typically used with the
8948 @var{init-string} option.
8950 @item @code{no-hints?} (default: @code{#f})
8951 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
8954 @item @code{no-hostname?} (default: @code{#f})
8955 By default, the hostname is printed. When this option is set to
8956 @code{#t}, no hostname will be shown at all.
8958 @item @code{long-hostname?} (default: @code{#f})
8959 By default, the hostname is only printed until the first dot. When this
8960 option is set to @code{#t}, the fully qualified hostname by
8961 @code{gethostname} or @code{getaddrinfo} is shown.
8963 @item @code{erase-characters} (default: @code{#f})
8964 This option accepts a string of additional characters that should be
8965 interpreted as backspace when the user types their login name.
8967 @item @code{kill-characters} (default: @code{#f})
8968 This option accepts a string that should be interpreted to mean "ignore
8969 all previous characters" (also called a "kill" character) when the types
8972 @item @code{chdir} (default: @code{#f})
8973 This option accepts, as a string, a directory path that will be changed
8976 @item @code{delay} (default: @code{#f})
8977 This options accepts, as an integer, the number of seconds to sleep
8978 before opening the tty and displaying the login prompt.
8980 @item @code{nice} (default: @code{#f})
8981 This option accepts, as an integer, the nice value with which to run the
8982 @command{login} program.
8984 @item @code{extra-options} (default: @code{'()})
8985 This option provides an "escape hatch" for the user to provide arbitrary
8986 command-line arguments to @command{agetty} as a list of strings.
8991 @deffn {Scheme Procedure} kmscon-service-type @var{config}
8992 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
8993 according to @var{config}, a @code{<kmscon-configuration>} object, which
8994 specifies the tty to run, among other things.
8997 @deftp {Data Type} kmscon-configuration
8998 This is the data type representing the configuration of Kmscon, which
8999 implements virtual console log-in.
9003 @item @code{virtual-terminal}
9004 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9006 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9007 A gexp denoting the name of the log-in program. The default log-in program is
9008 @command{login} from the Shadow tool suite.
9010 @item @code{login-arguments} (default: @code{'("-p")})
9011 A list of arguments to pass to @command{login}.
9013 @item @code{hardware-acceleration?} (default: #f)
9014 Whether to use hardware acceleration.
9016 @item @code{kmscon} (default: @var{kmscon})
9017 The Kmscon package to use.
9022 @cindex name service cache daemon
9024 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9025 [#:name-services '()]
9026 Return a service that runs the libc name service cache daemon (nscd) with the
9027 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9028 Service Switch}, for an example.
9031 @defvr {Scheme Variable} %nscd-default-configuration
9032 This is the default @code{<nscd-configuration>} value (see below) used
9033 by @code{nscd-service}. It uses the caches defined by
9034 @var{%nscd-default-caches}; see below.
9037 @deftp {Data Type} nscd-configuration
9038 This is the data type representing the name service cache daemon (nscd)
9043 @item @code{name-services} (default: @code{'()})
9044 List of packages denoting @dfn{name services} that must be visible to
9045 the nscd---e.g., @code{(list @var{nss-mdns})}.
9047 @item @code{glibc} (default: @var{glibc})
9048 Package object denoting the GNU C Library providing the @command{nscd}
9051 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9052 Name of the nscd log file. This is where debugging output goes when
9053 @code{debug-level} is strictly positive.
9055 @item @code{debug-level} (default: @code{0})
9056 Integer denoting the debugging levels. Higher numbers mean that more
9057 debugging output is logged.
9059 @item @code{caches} (default: @var{%nscd-default-caches})
9060 List of @code{<nscd-cache>} objects denoting things to be cached; see
9066 @deftp {Data Type} nscd-cache
9067 Data type representing a cache database of nscd and its parameters.
9071 @item @code{database}
9072 This is a symbol representing the name of the database to be cached.
9073 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9074 @code{services}, which designate the corresponding NSS database
9075 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9077 @item @code{positive-time-to-live}
9078 @itemx @code{negative-time-to-live} (default: @code{20})
9079 A number representing the number of seconds during which a positive or
9080 negative lookup result remains in cache.
9082 @item @code{check-files?} (default: @code{#t})
9083 Whether to check for updates of the files corresponding to
9086 For instance, when @var{database} is @code{hosts}, setting this flag
9087 instructs nscd to check for updates in @file{/etc/hosts} and to take
9090 @item @code{persistent?} (default: @code{#t})
9091 Whether the cache should be stored persistently on disk.
9093 @item @code{shared?} (default: @code{#t})
9094 Whether the cache should be shared among users.
9096 @item @code{max-database-size} (default: 32@tie{}MiB)
9097 Maximum size in bytes of the database cache.
9099 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9100 @c settings, so leave them out.
9105 @defvr {Scheme Variable} %nscd-default-caches
9106 List of @code{<nscd-cache>} objects used by default by
9107 @code{nscd-configuration} (see above).
9109 It enables persistent and aggressive caching of service and host name
9110 lookups. The latter provides better host name lookup performance,
9111 resilience in the face of unreliable name servers, and also better
9112 privacy---often the result of host name lookups is in local cache, so
9113 external name servers do not even need to be queried.
9116 @anchor{syslog-configuration-type}
9119 @deftp {Data Type} syslog-configuration
9120 This data type represents the configuration of the syslog daemon.
9123 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9124 The syslog daemon to use.
9126 @item @code{config-file} (default: @code{%default-syslog.conf})
9127 The syslog configuration file to use.
9132 @anchor{syslog-service}
9134 @deffn {Scheme Procedure} syslog-service @var{config}
9135 Return a service that runs a syslog daemon according to @var{config}.
9137 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9138 information on the configuration file syntax.
9141 @anchor{guix-configuration-type}
9142 @deftp {Data Type} guix-configuration
9143 This data type represents the configuration of the Guix build daemon.
9144 @xref{Invoking guix-daemon}, for more information.
9147 @item @code{guix} (default: @var{guix})
9148 The Guix package to use.
9150 @item @code{build-group} (default: @code{"guixbuild"})
9151 Name of the group for build user accounts.
9153 @item @code{build-accounts} (default: @code{10})
9154 Number of build user accounts to create.
9156 @item @code{authorize-key?} (default: @code{#t})
9157 @cindex substitutes, authorization thereof
9158 Whether to authorize the substitute keys listed in
9159 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9160 (@pxref{Substitutes}).
9162 @vindex %default-authorized-guix-keys
9163 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9164 The list of authorized key files for archive imports, as a list of
9165 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9166 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9168 @item @code{use-substitutes?} (default: @code{#t})
9169 Whether to use substitutes.
9171 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9172 The list of URLs where to look for substitutes by default.
9174 @item @code{extra-options} (default: @code{'()})
9175 List of extra command-line options for @command{guix-daemon}.
9177 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9178 File where @command{guix-daemon}'s standard output and standard error
9181 @item @code{lsof} (default: @var{lsof})
9182 The lsof package to use.
9184 @item @code{http-proxy} (default: @code{#f})
9185 The HTTP proxy used for downloading fixed-output derivations and
9188 @item @code{tmpdir} (default: @code{#f})
9189 A directory path where the @command{guix-daemon} will perform builds.
9194 @deffn {Scheme Procedure} guix-service @var{config}
9195 Return a service that runs the Guix build daemon according to
9199 @deffn {Scheme Procedure} udev-service [#:udev udev]
9200 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9203 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9204 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9208 @defvr {Scheme Variable} %random-seed-file
9209 This is the name of the file where some random bytes are saved by
9210 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9211 It defaults to @file{/var/lib/random-seed}.
9216 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9217 @cindex keyboard layout
9218 Return a service to load console keymaps from @var{files} using
9219 @command{loadkeys} command. Most likely, you want to load some default
9220 keymap, which can be done like this:
9223 (console-keymap-service "dvorak")
9226 Or, for example, for a Swedish keyboard, you may need to combine
9227 the following keymaps:
9229 (console-keymap-service "se-lat6" "se-fi-lat6")
9232 Also you can specify a full file name (or file names) of your keymap(s).
9233 See @code{man loadkeys} for details.
9239 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9241 Run @var{gpm}, the general-purpose mouse daemon, with the given
9242 command-line @var{options}. GPM allows users to use the mouse in the console,
9243 notably to select, copy, and paste text. The default value of @var{options}
9244 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9246 This service is not part of @var{%base-services}.
9249 @anchor{guix-publish-service-type}
9250 @deffn {Scheme Variable} guix-publish-service-type
9251 This is the service type for @command{guix publish} (@pxref{Invoking
9252 guix publish}). Its value must be a @code{guix-configuration}
9253 object, as described below.
9255 This assumes that @file{/etc/guix} already contains a signing key pair as
9256 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9257 archive}). If that is not the case, the service will fail to start.
9260 @deftp {Data Type} guix-publish-configuration
9261 Data type representing the configuration of the @code{guix publish}
9265 @item @code{guix} (default: @code{guix})
9266 The Guix package to use.
9268 @item @code{port} (default: @code{80})
9269 The TCP port to listen for connections.
9271 @item @code{host} (default: @code{"localhost"})
9272 The host (and thus, network interface) to listen to. Use
9273 @code{"0.0.0.0"} to listen on all the network interfaces.
9275 @item @code{compression-level} (default: @code{3})
9276 The gzip compression level at which substitutes are compressed. Use
9277 @code{0} to disable compression altogether, and @code{9} to get the best
9278 compression ratio at the expense of increased CPU usage.
9280 @item @code{nar-path} (default: @code{"nar"})
9281 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9282 publish, @code{--nar-path}}, for details.
9284 @item @code{cache} (default: @code{#f})
9285 When it is @code{#f}, disable caching and instead generate archives on
9286 demand. Otherwise, this should be the name of a directory---e.g.,
9287 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9288 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9289 @option{--cache}}, for more information on the tradeoffs involved.
9291 @item @code{workers} (default: @code{#f})
9292 When it is an integer, this is the number of worker threads used for
9293 caching; when @code{#f}, the number of processors is used.
9294 @xref{Invoking guix publish, @option{--workers}}, for more information.
9296 @item @code{ttl} (default: @code{#f})
9297 When it is an integer, this denotes the @dfn{time-to-live} of the
9298 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9303 @anchor{rngd-service}
9304 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9305 [#:device "/dev/hwrng"]
9306 Return a service that runs the @command{rngd} program from @var{rng-tools}
9307 to add @var{device} to the kernel's entropy pool. The service will fail if
9308 @var{device} does not exist.
9311 @anchor{pam-limits-service}
9312 @cindex session limits
9315 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9317 Return a service that installs a configuration file for the
9318 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9319 @code{pam_limits} module}. The procedure optionally takes a list of
9320 @code{pam-limits-entry} values, which can be used to specify
9321 @code{ulimit} limits and nice priority limits to user sessions.
9323 The following limits definition sets two hard and soft limits for all
9324 login sessions of users in the @code{realtime} group:
9329 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9330 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9333 The first entry increases the maximum realtime priority for
9334 non-privileged processes; the second entry lifts any restriction of the
9335 maximum address space that can be locked in memory. These settings are
9336 commonly used for real-time audio systems.
9339 @node Scheduled Job Execution
9340 @subsubsection Scheduled Job Execution
9344 @cindex scheduling jobs
9345 The @code{(gnu services mcron)} module provides an interface to
9346 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9347 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9348 Unix @command{cron} daemon; the main difference is that it is
9349 implemented in Guile Scheme, which provides a lot of flexibility when
9350 specifying the scheduling of jobs and their actions.
9352 The example below defines an operating system that runs the
9353 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9354 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9355 well as the @command{mkid} command on behalf of an unprivileged user
9356 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9357 gexps to introduce job definitions that are passed to mcron
9358 (@pxref{G-Expressions}).
9361 (use-modules (guix) (gnu) (gnu services mcron))
9362 (use-package-modules base idutils)
9364 (define updatedb-job
9365 ;; Run 'updatedb' at 3AM every day. Here we write the
9366 ;; job's action as a Scheme procedure.
9367 #~(job '(next-hour '(3))
9369 (execl (string-append #$findutils "/bin/updatedb")
9371 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9373 (define garbage-collector-job
9374 ;; Collect garbage 5 minutes after midnight every day.
9375 ;; The job's action is a shell command.
9376 #~(job "5 0 * * *" ;Vixie cron syntax
9380 ;; Update the index database as user "charlie" at 12:15PM
9381 ;; and 19:15PM. This runs from the user's home directory.
9382 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9383 (string-append #$idutils "/bin/mkid src")
9388 (services (cons (mcron-service (list garbage-collector-job
9394 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9395 for more information on mcron job specifications. Below is the
9396 reference of the mcron service.
9398 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9399 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9400 list of gexps denoting mcron job specifications.
9402 This is a shorthand for:
9404 (service mcron-service-type
9405 (mcron-configuration (mcron mcron) (jobs jobs)))
9409 @defvr {Scheme Variable} mcron-service-type
9410 This is the type of the @code{mcron} service, whose value is an
9411 @code{mcron-configuration} object.
9413 This service type can be the target of a service extension that provides
9414 it additional job specifications (@pxref{Service Composition}). In
9415 other words, it is possible to define services that provide additional
9419 @deftp {Data Type} mcron-configuration
9420 Data type representing the configuration of mcron.
9423 @item @code{mcron} (default: @var{mcron2})
9424 The mcron package to use.
9427 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9428 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9429 specifications,, mcron, GNU@tie{}mcron}).
9435 @subsubsection Log Rotation
9438 @cindex log rotation
9440 Log files such as those found in @file{/var/log} tend to grow endlessly,
9441 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9442 their contents in separate files, possibly compressed. The @code{(gnu
9443 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9444 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9446 The example below defines an operating system that provides log rotation
9447 with the default settings.
9450 (use-modules (guix) (gnu))
9451 (use-service-modules admin mcron)
9452 (use-package-modules base idutils)
9456 (services (cons* (mcron-service)
9457 (service rottlog-service-type)
9461 @defvr {Scheme Variable} rottlog-service-type
9462 This is the type of the Rottlog service, whose value is a
9463 @code{rottlog-configuration} object.
9465 This service type can define mcron jobs (@pxref{Scheduled Job
9466 Execution}) to run the rottlog service.
9469 @deftp {Data Type} rottlog-configuration
9470 Data type representing the configuration of rottlog.
9473 @item @code{rottlog} (default: @code{rottlog})
9474 The Rottlog package to use.
9476 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9477 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9478 rottlog, GNU Rot[t]log Manual}).
9480 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9481 A list of Rottlog period-name/period-config tuples.
9483 For example, taking an example from the Rottlog manual (@pxref{Period
9484 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9488 ("daily" ,(plain-file "daily"
9490 /var/log/apache/* @{
9491 storedir apache-archives
9499 This is a list of gexps where each gexp corresponds to an mcron job
9500 specification (@pxref{Scheduled Job Execution}).
9504 @defvr {Scheme Variable} %default-rotations
9505 Specifies weekly rotation of @var{%rotated-files} and
9506 @code{"/var/log/shepherd.log"}.
9509 @defvr {Scheme Variable} %rotated-files
9510 The list of syslog-controlled files to be rotated. By default it is:
9511 @code{'("/var/log/messages" "/var/log/secure")}.
9514 @node Networking Services
9515 @subsubsection Networking Services
9517 The @code{(gnu services networking)} module provides services to configure
9518 the network interface.
9520 @cindex DHCP, networking service
9521 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9522 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9523 Protocol (DHCP) client, on all the non-loopback network interfaces.
9526 @defvr {Scheme Variable} static-networking-service-type
9527 This is the type for statically-configured network interfaces.
9528 @c TODO Document <static-networking> data structures.
9531 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9532 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9533 Return a service that starts @var{interface} with address @var{ip}. If
9534 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9535 it must be a string specifying the default network gateway.
9537 This procedure can be called several times, one for each network
9538 interface of interest. Behind the scenes what it does is extend
9539 @code{static-networking-service-type} with additional network interfaces
9546 @cindex network management
9547 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9548 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9549 management daemon that aims to simplify wired and wireless networking.
9551 This service adds the @var{wicd} package to the global profile, providing
9552 several commands to interact with the daemon and configure networking:
9553 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9554 and @command{wicd-curses} user interfaces.
9557 @cindex NetworkManager
9559 @defvr {Scheme Variable} network-manager-service-type
9560 This is the service type for the
9561 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9562 service. The value for this service type is a
9563 @code{network-manager-configuration} record.
9566 @deftp {Data Type} network-manager-configuration
9567 Data type representing the configuration of NetworkManager.
9570 @item @code{network-manager} (default: @code{network-manager})
9571 The NetworkManager package to use.
9573 @item @code{dns} (default: @code{"default"})
9574 Processing mode for DNS, which affects how NetworkManager uses the
9575 @code{resolv.conf} configuration file.
9579 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9580 provided by currently active connections.
9583 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9584 using a "split DNS" configuration if you are connected to a VPN, and
9585 then update @code{resolv.conf} to point to the local nameserver.
9588 NetworkManager will not modify @code{resolv.conf}.
9595 @deffn {Scheme Variable} connman-service-type
9596 This is the service type to run @url{https://01.org/connman,Connman},
9597 a network connection manager.
9599 Its value must be an
9600 @code{connman-configuration} record as in this example:
9603 (service connman-service-type
9604 (connman-configuration
9608 See below for details about @code{connman-configuration}.
9611 @deftp {Data Type} connman-configuration
9612 Data Type representing the configuration of connman.
9615 @item @code{connman} (default: @var{connman})
9616 The connman package to use.
9618 @item @code{disable-vpn?} (default: @code{#f})
9619 When true, enable connman's vpn plugin.
9623 @cindex WPA Supplicant
9624 @defvr {Scheme Variable} wpa-supplicant-service-type
9625 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9626 supplicant}, an authentication daemon required to authenticate against
9627 encrypted WiFi or ethernet networks. It is configured to listen for
9630 The value of this service is the @code{wpa-supplicant} package to use.
9631 Thus, it can be instantiated like this:
9634 (use-modules (gnu services networking))
9636 (service wpa-supplicant-service-type)
9641 @cindex real time clock
9642 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9643 [#:servers @var{%ntp-servers}] @
9644 [#:allow-large-adjustment? #f]
9645 Return a service that runs the daemon from @var{ntp}, the
9646 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9647 keep the system clock synchronized with that of @var{servers}.
9648 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9649 make an initial adjustment of more than 1,000 seconds.
9652 @defvr {Scheme Variable} %ntp-servers
9653 List of host names used as the default NTP servers.
9657 @deffn {Scheme variable} inetd-service-type
9658 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9659 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9660 connections on internet sockets, and lazily starts the specified server
9661 program when a connection is made on one of these sockets.
9663 The value of this service is an @code{inetd-configuration} object. The
9664 following example configures the @command{inetd} daemon to provide the
9665 built-in @command{echo} service, as well as an smtp service which
9666 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9667 gateway @code{hostname}:
9672 (inetd-configuration
9676 (socket-type 'stream)
9683 (socket-type 'stream)
9687 (program (file-append openssh "/bin/ssh"))
9689 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9690 "-W" "smtp-server:25" "user@@hostname")))))
9693 See below for more details about @code{inetd-configuration}.
9696 @deftp {Data Type} inetd-configuration
9697 Data type representing the configuration of @command{inetd}.
9700 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9701 The @command{inetd} executable to use.
9703 @item @code{entries} (default: @code{'()})
9704 A list of @command{inetd} service entries. Each entry should be created
9705 by the @code{inetd-entry} constructor.
9709 @deftp {Data Type} inetd-entry
9710 Data type representing an entry in the @command{inetd} configuration.
9711 Each entry corresponds to a socket where @command{inetd} will listen for
9715 @item @code{node} (default: @code{#f})
9716 Optional string, a comma-separated list of local addresses
9717 @command{inetd} should use when listening for this service.
9718 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9719 description of all options.
9721 A string, the name must correspond to an entry in @code{/etc/services}.
9722 @item @code{socket-type}
9723 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9725 @item @code{protocol}
9726 A string, must correspond to an entry in @code{/etc/protocols}.
9727 @item @code{wait?} (default: @code{#t})
9728 Whether @command{inetd} should wait for the server to exit before
9729 listening to new service requests.
9731 A string containing the user (and, optionally, group) name of the user
9732 as whom the server should run. The group name can be specified in a
9733 suffix, separated by a colon or period, i.e. @code{"user"},
9734 @code{"user:group"} or @code{"user.group"}.
9735 @item @code{program} (default: @code{"internal"})
9736 The server program which will serve the requests, or @code{"internal"}
9737 if @command{inetd} should use a built-in service.
9738 @item @code{arguments} (default: @code{'()})
9739 A list strings or file-like objects, which are the server program's
9740 arguments, starting with the zeroth argument, i.e. the name of the
9741 program itself. For @command{inetd}'s internal services, this entry
9742 must be @code{'()} or @code{'("internal")}.
9745 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9746 detailed discussion of each configuration field.
9750 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9751 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9754 The daemon runs as the @code{tor} unprivileged user. It is passed
9755 @var{config-file}, a file-like object, with an additional @code{User tor} line
9756 and lines for hidden services added via @code{tor-hidden-service}. Run
9757 @command{man tor} for information about the configuration file.
9760 @cindex hidden service
9761 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9762 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9763 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9766 '((22 "127.0.0.1:22")
9767 (80 "127.0.0.1:8080"))
9770 In this example, port 22 of the hidden service is mapped to local port 22, and
9771 port 80 is mapped to local port 8080.
9773 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9774 the @file{hostname} file contains the @code{.onion} host name for the hidden
9777 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9778 project's documentation} for more information.
9781 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9782 [#:interface "127.0.0.1"] [#:port 6667] @
9783 [#:extra-settings ""]
9784 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9785 acts as a gateway between IRC and chat networks.
9787 The daemon will listen to the interface corresponding to the IP address
9788 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9789 local clients can connect, whereas @code{0.0.0.0} means that connections can
9790 come from any networking interface.
9792 In addition, @var{extra-settings} specifies a string to append to the
9796 Furthermore, @code{(gnu services ssh)} provides the following services.
9800 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9801 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9802 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9803 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9804 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9805 [#:public-key-authentication? #t] [#:initialize? #t]
9806 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9807 @var{host-key} must designate a file containing the host key, and readable
9810 When @var{daemonic?} is true, @command{lshd} will detach from the
9811 controlling terminal and log its output to syslogd, unless one sets
9812 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9813 depend on existence of syslogd service. When @var{pid-file?} is true,
9814 @command{lshd} writes its PID to the file called @var{pid-file}.
9816 When @var{initialize?} is true, automatically create the seed and host key
9817 upon service activation if they do not exist yet. This may take long and
9818 require interaction.
9820 When @var{initialize?} is false, it is up to the user to initialize the
9821 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9822 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9823 basics,,, lsh, LSH Manual}).
9825 When @var{interfaces} is empty, lshd listens for connections on all the
9826 network interfaces; otherwise, @var{interfaces} must be a list of host names
9829 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9830 passwords, and @var{root-login?} specifies whether to accept log-ins as
9833 The other options should be self-descriptive.
9838 @deffn {Scheme Variable} openssh-service-type
9839 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9840 shell daemon, @command{sshd}. Its value must be an
9841 @code{openssh-configuration} record as in this example:
9844 (service openssh-service-type
9845 (openssh-configuration
9846 (x11-forwarding? #t)
9847 (permit-root-login 'without-password)))
9850 See below for details about @code{openssh-configuration}.
9853 @deftp {Data Type} openssh-configuration
9854 This is the configuration record for OpenSSH's @command{sshd}.
9857 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9858 Name of the file where @command{sshd} writes its PID.
9860 @item @code{port-number} (default: @code{22})
9861 TCP port on which @command{sshd} listens for incoming connections.
9863 @item @code{permit-root-login} (default: @code{#f})
9864 This field determines whether and when to allow logins as root. If
9865 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9866 If it's the symbol @code{'without-password}, then root logins are
9867 permitted but not with password-based authentication.
9869 @item @code{allow-empty-passwords?} (default: @code{#f})
9870 When true, users with empty passwords may log in. When false, they may
9873 @item @code{password-authentication?} (default: @code{#t})
9874 When true, users may log in with their password. When false, they have
9875 other authentication methods.
9877 @item @code{public-key-authentication?} (default: @code{#t})
9878 When true, users may log in using public key authentication. When
9879 false, users have to use other authentication method.
9881 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9882 This is used only by protocol version 2.
9884 @item @code{x11-forwarding?} (default: @code{#f})
9885 When true, forwarding of X11 graphical client connections is
9886 enabled---in other words, @command{ssh} options @option{-X} and
9887 @option{-Y} will work.
9889 @item @code{challenge-response-authentication?} (default: @code{#f})
9890 Specifies whether challenge response authentication is allowed (e.g. via
9893 @item @code{use-pam?} (default: @code{#t})
9894 Enables the Pluggable Authentication Module interface. If set to
9895 @code{#t}, this will enable PAM authentication using
9896 @code{challenge-response-authentication?} and
9897 @code{password-authentication?}, in addition to PAM account and session
9898 module processing for all authentication types.
9900 Because PAM challenge response authentication usually serves an
9901 equivalent role to password authentication, you should disable either
9902 @code{challenge-response-authentication?} or
9903 @code{password-authentication?}.
9905 @item @code{print-last-log?} (default: @code{#t})
9906 Specifies whether @command{sshd} should print the date and time of the
9907 last user login when a user logs in interactively.
9909 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
9910 Configures external subsystems (e.g. file transfer daemon).
9912 This is a list of two-element lists, each of which containing the
9913 subsystem name and a command (with optional arguments) to execute upon
9916 The command @command{internal-sftp} implements an in-process SFTP
9917 server. Alternately, one can specify the @command{sftp-server} command:
9919 (service openssh-service-type
9920 (openssh-configuration
9922 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
9927 @deffn {Scheme Procedure} dropbear-service [@var{config}]
9928 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
9929 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
9932 For example, to specify a Dropbear service listening on port 1234, add
9933 this call to the operating system's @code{services} field:
9936 (dropbear-service (dropbear-configuration
9937 (port-number 1234)))
9941 @deftp {Data Type} dropbear-configuration
9942 This data type represents the configuration of a Dropbear SSH daemon.
9945 @item @code{dropbear} (default: @var{dropbear})
9946 The Dropbear package to use.
9948 @item @code{port-number} (default: 22)
9949 The TCP port where the daemon waits for incoming connections.
9951 @item @code{syslog-output?} (default: @code{#t})
9952 Whether to enable syslog output.
9954 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
9955 File name of the daemon's PID file.
9957 @item @code{root-login?} (default: @code{#f})
9958 Whether to allow @code{root} logins.
9960 @item @code{allow-empty-passwords?} (default: @code{#f})
9961 Whether to allow empty passwords.
9963 @item @code{password-authentication?} (default: @code{#t})
9964 Whether to enable password-based authentication.
9968 @defvr {Scheme Variable} %facebook-host-aliases
9969 This variable contains a string for use in @file{/etc/hosts}
9970 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
9971 line contains a entry that maps a known server name of the Facebook
9972 on-line service---e.g., @code{www.facebook.com}---to the local
9973 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
9975 This variable is typically used in the @code{hosts-file} field of an
9976 @code{operating-system} declaration (@pxref{operating-system Reference,
9977 @file{/etc/hosts}}):
9980 (use-modules (gnu) (guix))
9983 (host-name "mymachine")
9986 ;; Create a /etc/hosts file with aliases for "localhost"
9987 ;; and "mymachine", as well as for Facebook servers.
9989 (string-append (local-host-aliases host-name)
9990 %facebook-host-aliases))))
9993 This mechanism can prevent programs running locally, such as Web
9994 browsers, from accessing Facebook.
9997 The @code{(gnu services avahi)} provides the following definition.
9999 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10000 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10001 [#:ipv6? #t] [#:wide-area? #f] @
10002 [#:domains-to-browse '()] [#:debug? #f]
10003 Return a service that runs @command{avahi-daemon}, a system-wide
10004 mDNS/DNS-SD responder that allows for service discovery and
10005 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10006 extends the name service cache daemon (nscd) so that it can resolve
10007 @code{.local} host names using
10008 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10009 add the @var{avahi} package to the system profile so that commands such as
10010 @command{avahi-browse} are directly usable.
10012 If @var{host-name} is different from @code{#f}, use that as the host name to
10013 publish for this machine; otherwise, use the machine's actual host name.
10015 When @var{publish?} is true, publishing of host names and services is allowed;
10016 in particular, avahi-daemon will publish the machine's host name and IP
10017 address via mDNS on the local network.
10019 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10021 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10025 @deffn {Scheme Variable} openvswitch-service-type
10026 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10027 service, whose value should be an @code{openvswitch-configuration}
10031 @deftp {Data Type} openvswitch-configuration
10032 Data type representing the configuration of Open vSwitch, a multilayer
10033 virtual switch which is designed to enable massive network automation
10034 through programmatic extension.
10037 @item @code{package} (default: @var{openvswitch})
10038 Package object of the Open vSwitch.
10044 @subsubsection X Window
10047 @cindex X Window System
10048 Support for the X Window graphical display system---specifically
10049 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10050 there is no @code{xorg-service} procedure. Instead, the X server is
10051 started by the @dfn{login manager}, currently SLiM.
10053 @deftp {Data Type} sddm-configuration
10054 This is the data type representing the sddm service configuration.
10057 @item @code{display-server} (default: "x11")
10058 Select display server to use for the greeter. Valid values are "x11"
10061 @item @code{numlock} (default: "on")
10062 Valid values are "on", "off" or "none".
10064 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10065 Command to run when halting.
10067 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10068 Command to run when rebooting.
10070 @item @code{theme} (default "maldives")
10071 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10073 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10074 Directory to look for themes.
10076 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10077 Directory to look for faces.
10079 @item @code{default-path} (default "/run/current-system/profile/bin")
10080 Default PATH to use.
10082 @item @code{minimum-uid} (default 1000)
10083 Minimum UID to display in SDDM.
10085 @item @code{maximum-uid} (default 2000)
10086 Maximum UID to display in SDDM
10088 @item @code{remember-last-user?} (default #t)
10089 Remember last user.
10091 @item @code{remember-last-session?} (default #t)
10092 Remember last session.
10094 @item @code{hide-users} (default "")
10095 Usernames to hide from SDDM greeter.
10097 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10098 Users with shells listed will be hidden from the SDDM greeter.
10100 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10101 Script to run before starting a wayland session.
10103 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10104 Directory to look for desktop files starting wayland sessions.
10106 @item @code{xorg-server-path} (default @code{xorg-start-command})
10107 Path to xorg-server.
10109 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10112 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10115 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10116 Script to run after starting xorg-server.
10118 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10119 Script to run before stopping xorg-server.
10121 @item @code{xsession-command} (default: @code{xinitr })
10122 Script to run before starting a X session.
10124 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10125 Directory to look for desktop files starting X sessions.
10127 @item @code{minimum-vt} (default: 7)
10130 @item @code{xserver-arguments} (default "-nolisten tcp")
10131 Arguments to pass to xorg-server.
10133 @item @code{auto-login-user} (default "")
10134 User to use for auto-login.
10136 @item @code{auto-login-session} (default "")
10137 Desktop file to use for auto-login.
10139 @item @code{relogin?} (default #f)
10140 Relogin after logout.
10145 @cindex login manager
10146 @deffn {Scheme Procedure} sddm-service config
10147 Return a service that spawns the SDDM graphical login manager for config of
10148 type @code{<sddm-configuration>}.
10151 (sddm-service (sddm-configuration
10152 (auto-login-user "Alice")
10153 (auto-login-session "xfce.desktop")))
10157 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10158 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10159 [#:theme @var{%default-slim-theme}] @
10160 [#:theme-name @var{%default-slim-theme-name}]
10161 Return a service that spawns the SLiM graphical login manager, which in
10162 turn starts the X display server with @var{startx}, a command as returned by
10163 @code{xorg-start-command}.
10167 SLiM automatically looks for session types described by the @file{.desktop}
10168 files in @file{/run/current-system/profile/share/xsessions} and allows users
10169 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10170 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10171 adding them to the system-wide set of packages automatically makes them
10172 available at the log-in screen.
10174 In addition, @file{~/.xsession} files are honored. When available,
10175 @file{~/.xsession} must be an executable that starts a window manager
10176 and/or other X clients.
10178 When @var{allow-empty-passwords?} is true, allow logins with an empty
10179 password. When @var{auto-login?} is true, log in automatically as
10180 @var{default-user}.
10182 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10183 @var{theme} must be a gexp denoting the name of a directory containing the
10184 theme to use. In that case, @var{theme-name} specifies the name of the
10188 @defvr {Scheme Variable} %default-theme
10189 @defvrx {Scheme Variable} %default-theme-name
10190 The G-Expression denoting the default SLiM theme and its name.
10193 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10194 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10195 Return a derivation that builds a @var{guile} script to start the X server
10196 from @var{xorg-server}. @var{configuration-file} is the server configuration
10197 file or a derivation that builds it; when omitted, the result of
10198 @code{xorg-configuration-file} is used.
10200 Usually the X server is started by a login manager.
10203 @deffn {Scheme Procedure} xorg-configuration-file @
10204 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10205 Return a configuration file for the Xorg server containing search paths for
10206 all the common drivers.
10208 @var{drivers} must be either the empty list, in which case Xorg chooses a
10209 graphics driver automatically, or a list of driver names that will be tried in
10210 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10212 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10213 appropriate screen resolution; otherwise, it must be a list of
10214 resolutions---e.g., @code{((1024 768) (640 480))}.
10216 Last, @var{extra-config} is a list of strings or objects appended to the
10217 @code{text-file*} argument list. It is used to pass extra text to be added
10218 verbatim to the configuration file.
10221 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10222 Add @var{package}, a package for a screen-locker or screen-saver whose
10223 command is @var{program}, to the set of setuid programs and add a PAM entry
10224 for it. For example:
10227 (screen-locker-service xlockmore "xlock")
10230 makes the good ol' XlockMore usable.
10234 @node Printing Services
10235 @subsubsection Printing Services
10237 @cindex printer support with CUPS
10238 The @code{(gnu services cups)} module provides a Guix service definition
10239 for the CUPS printing service. To add printer support to a GuixSD
10240 system, add a @code{cups-service} to the operating system definition:
10242 @deffn {Scheme Variable} cups-service-type
10243 The service type for the CUPS print server. Its value should be a valid
10244 CUPS configuration (see below). To use the default settings, simply
10247 (service cups-service-type)
10251 The CUPS configuration controls the basic things about your CUPS
10252 installation: what interfaces it listens on, what to do if a print job
10253 fails, how much logging to do, and so on. To actually add a printer,
10254 you have to visit the @url{http://localhost:631} URL, or use a tool such
10255 as GNOME's printer configuration services. By default, configuring a
10256 CUPS service will generate a self-signed certificate if needed, for
10257 secure connections to the print server.
10259 Suppose you want to enable the Web interface of CUPS and also add
10260 support for HP printers @i{via} the @code{hplip} package. You can do
10261 that directly, like this (you need to use the @code{(gnu packages cups)}
10265 (service cups-service-type
10266 (cups-configuration
10267 (web-interface? #t)
10269 (list cups-filters hplip))))
10272 The available configuration parameters follow. Each parameter
10273 definition is preceded by its type; for example, @samp{string-list foo}
10274 indicates that the @code{foo} parameter should be specified as a list of
10275 strings. There is also a way to specify the configuration as a string,
10276 if you have an old @code{cupsd.conf} file that you want to port over
10277 from some other system; see the end for more details.
10279 @c The following documentation was initially generated by
10280 @c (generate-documentation) in (gnu services cups). Manually maintained
10281 @c documentation is better, so we shouldn't hesitate to edit below as
10282 @c needed. However if the change you want to make to this documentation
10283 @c can be done in an automated way, it's probably easier to change
10284 @c (generate-documentation) than to make it below and have to deal with
10285 @c the churn as CUPS updates.
10288 Available @code{cups-configuration} fields are:
10290 @deftypevr {@code{cups-configuration} parameter} package cups
10294 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10295 Drivers and other extensions to the CUPS package.
10298 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10299 Configuration of where to write logs, what directories to use for print
10300 spools, and related privileged configuration parameters.
10302 Available @code{files-configuration} fields are:
10304 @deftypevr {@code{files-configuration} parameter} log-location access-log
10305 Defines the access log filename. Specifying a blank filename disables
10306 access log generation. The value @code{stderr} causes log entries to be
10307 sent to the standard error file when the scheduler is running in the
10308 foreground, or to the system log daemon when run in the background. The
10309 value @code{syslog} causes log entries to be sent to the system log
10310 daemon. The server name may be included in filenames using the string
10311 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10313 Defaults to @samp{"/var/log/cups/access_log"}.
10316 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10317 Where CUPS should cache data.
10319 Defaults to @samp{"/var/cache/cups"}.
10322 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10323 Specifies the permissions for all configuration files that the scheduler
10326 Note that the permissions for the printers.conf file are currently
10327 masked to only allow access from the scheduler user (typically root).
10328 This is done because printer device URIs sometimes contain sensitive
10329 authentication information that should not be generally known on the
10330 system. There is no way to disable this security feature.
10332 Defaults to @samp{"0640"}.
10335 @deftypevr {@code{files-configuration} parameter} log-location error-log
10336 Defines the error log filename. Specifying a blank filename disables
10337 access log generation. The value @code{stderr} causes log entries to be
10338 sent to the standard error file when the scheduler is running in the
10339 foreground, or to the system log daemon when run in the background. The
10340 value @code{syslog} causes log entries to be sent to the system log
10341 daemon. The server name may be included in filenames using the string
10342 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10344 Defaults to @samp{"/var/log/cups/error_log"}.
10347 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10348 Specifies which errors are fatal, causing the scheduler to exit. The
10353 No errors are fatal.
10356 All of the errors below are fatal.
10359 Browsing initialization errors are fatal, for example failed connections
10360 to the DNS-SD daemon.
10363 Configuration file syntax errors are fatal.
10366 Listen or Port errors are fatal, except for IPv6 failures on the
10367 loopback or @code{any} addresses.
10370 Log file creation or write errors are fatal.
10373 Bad startup file permissions are fatal, for example shared TLS
10374 certificate and key files with world-read permissions.
10377 Defaults to @samp{"all -browse"}.
10380 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10381 Specifies whether the file pseudo-device can be used for new printer
10382 queues. The URI @uref{file:///dev/null} is always allowed.
10384 Defaults to @samp{#f}.
10387 @deftypevr {@code{files-configuration} parameter} string group
10388 Specifies the group name or ID that will be used when executing external
10391 Defaults to @samp{"lp"}.
10394 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10395 Specifies the permissions for all log files that the scheduler writes.
10397 Defaults to @samp{"0644"}.
10400 @deftypevr {@code{files-configuration} parameter} log-location page-log
10401 Defines the page log filename. Specifying a blank filename disables
10402 access log generation. The value @code{stderr} causes log entries to be
10403 sent to the standard error file when the scheduler is running in the
10404 foreground, or to the system log daemon when run in the background. The
10405 value @code{syslog} causes log entries to be sent to the system log
10406 daemon. The server name may be included in filenames using the string
10407 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10409 Defaults to @samp{"/var/log/cups/page_log"}.
10412 @deftypevr {@code{files-configuration} parameter} string remote-root
10413 Specifies the username that is associated with unauthenticated accesses
10414 by clients claiming to be the root user. The default is @code{remroot}.
10416 Defaults to @samp{"remroot"}.
10419 @deftypevr {@code{files-configuration} parameter} file-name request-root
10420 Specifies the directory that contains print jobs and other HTTP request
10423 Defaults to @samp{"/var/spool/cups"}.
10426 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10427 Specifies the level of security sandboxing that is applied to print
10428 filters, backends, and other child processes of the scheduler; either
10429 @code{relaxed} or @code{strict}. This directive is currently only
10430 used/supported on macOS.
10432 Defaults to @samp{strict}.
10435 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10436 Specifies the location of TLS certificates and private keys. CUPS will
10437 look for public and private keys in this directory: a @code{.crt} files
10438 for PEM-encoded certificates and corresponding @code{.key} files for
10439 PEM-encoded private keys.
10441 Defaults to @samp{"/etc/cups/ssl"}.
10444 @deftypevr {@code{files-configuration} parameter} file-name server-root
10445 Specifies the directory containing the server configuration files.
10447 Defaults to @samp{"/etc/cups"}.
10450 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10451 Specifies whether the scheduler calls fsync(2) after writing
10452 configuration or state files.
10454 Defaults to @samp{#f}.
10457 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10458 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10461 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10462 Specifies the directory where temporary files are stored.
10464 Defaults to @samp{"/var/spool/cups/tmp"}.
10467 @deftypevr {@code{files-configuration} parameter} string user
10468 Specifies the user name or ID that is used when running external
10471 Defaults to @samp{"lp"}.
10475 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10476 Specifies the logging level for the AccessLog file. The @code{config}
10477 level logs when printers and classes are added, deleted, or modified and
10478 when configuration files are accessed or updated. The @code{actions}
10479 level logs when print jobs are submitted, held, released, modified, or
10480 canceled, and any of the conditions for @code{config}. The @code{all}
10481 level logs all requests.
10483 Defaults to @samp{actions}.
10486 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10487 Specifies whether to purge job history data automatically when it is no
10488 longer required for quotas.
10490 Defaults to @samp{#f}.
10493 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10494 Specifies which protocols to use for local printer sharing.
10496 Defaults to @samp{dnssd}.
10499 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10500 Specifies whether the CUPS web interface is advertised.
10502 Defaults to @samp{#f}.
10505 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10506 Specifies whether shared printers are advertised.
10508 Defaults to @samp{#f}.
10511 @deftypevr {@code{cups-configuration} parameter} string classification
10512 Specifies the security classification of the server. Any valid banner
10513 name can be used, including "classified", "confidential", "secret",
10514 "topsecret", and "unclassified", or the banner can be omitted to disable
10515 secure printing functions.
10517 Defaults to @samp{""}.
10520 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10521 Specifies whether users may override the classification (cover page) of
10522 individual print jobs using the @code{job-sheets} option.
10524 Defaults to @samp{#f}.
10527 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10528 Specifies the default type of authentication to use.
10530 Defaults to @samp{Basic}.
10533 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10534 Specifies whether encryption will be used for authenticated requests.
10536 Defaults to @samp{Required}.
10539 @deftypevr {@code{cups-configuration} parameter} string default-language
10540 Specifies the default language to use for text and web content.
10542 Defaults to @samp{"en"}.
10545 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10546 Specifies the default paper size for new print queues. @samp{"Auto"}
10547 uses a locale-specific default, while @samp{"None"} specifies there is
10548 no default paper size. Specific size names are typically
10549 @samp{"Letter"} or @samp{"A4"}.
10551 Defaults to @samp{"Auto"}.
10554 @deftypevr {@code{cups-configuration} parameter} string default-policy
10555 Specifies the default access policy to use.
10557 Defaults to @samp{"default"}.
10560 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10561 Specifies whether local printers are shared by default.
10563 Defaults to @samp{#t}.
10566 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10567 Specifies the delay for updating of configuration and state files, in
10568 seconds. A value of 0 causes the update to happen as soon as possible,
10569 typically within a few milliseconds.
10571 Defaults to @samp{30}.
10574 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10575 Specifies what to do when an error occurs. Possible values are
10576 @code{abort-job}, which will discard the failed print job;
10577 @code{retry-job}, which will retry the job at a later time;
10578 @code{retry-this-job}, which retries the failed job immediately; and
10579 @code{stop-printer}, which stops the printer.
10581 Defaults to @samp{stop-printer}.
10584 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10585 Specifies the maximum cost of filters that are run concurrently, which
10586 can be used to minimize disk, memory, and CPU resource problems. A
10587 limit of 0 disables filter limiting. An average print to a
10588 non-PostScript printer needs a filter limit of about 200. A PostScript
10589 printer needs about half that (100). Setting the limit below these
10590 thresholds will effectively limit the scheduler to printing a single job
10593 Defaults to @samp{0}.
10596 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10597 Specifies the scheduling priority of filters that are run to print a
10598 job. The nice value ranges from 0, the highest priority, to 19, the
10601 Defaults to @samp{0}.
10604 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10605 Specifies whether to do reverse lookups on connecting clients. The
10606 @code{double} setting causes @code{cupsd} to verify that the hostname
10607 resolved from the address matches one of the addresses returned for that
10608 hostname. Double lookups also prevent clients with unregistered
10609 addresses from connecting to your server. Only set this option to
10610 @code{#t} or @code{double} if absolutely required.
10612 Defaults to @samp{#f}.
10615 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10616 Specifies the number of seconds to wait before killing the filters and
10617 backend associated with a canceled or held job.
10619 Defaults to @samp{30}.
10622 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10623 Specifies the interval between retries of jobs in seconds. This is
10624 typically used for fax queues but can also be used with normal print
10625 queues whose error policy is @code{retry-job} or
10626 @code{retry-current-job}.
10628 Defaults to @samp{30}.
10631 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10632 Specifies the number of retries that are done for jobs. This is
10633 typically used for fax queues but can also be used with normal print
10634 queues whose error policy is @code{retry-job} or
10635 @code{retry-current-job}.
10637 Defaults to @samp{5}.
10640 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10641 Specifies whether to support HTTP keep-alive connections.
10643 Defaults to @samp{#t}.
10646 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10647 Specifies how long an idle client connection remains open, in seconds.
10649 Defaults to @samp{30}.
10652 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10653 Specifies the maximum size of print files, IPP requests, and HTML form
10654 data. A limit of 0 disables the limit check.
10656 Defaults to @samp{0}.
10659 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10660 Listens on the specified interfaces for connections. Valid values are
10661 of the form @var{address}:@var{port}, where @var{address} is either an
10662 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10663 indicate all addresses. Values can also be file names of local UNIX
10664 domain sockets. The Listen directive is similar to the Port directive
10665 but allows you to restrict access to specific interfaces or networks.
10668 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10669 Specifies the number of pending connections that will be allowed. This
10670 normally only affects very busy servers that have reached the MaxClients
10671 limit, but can also be triggered by large numbers of simultaneous
10672 connections. When the limit is reached, the operating system will
10673 refuse additional connections until the scheduler can accept the pending
10676 Defaults to @samp{128}.
10679 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10680 Specifies a set of additional access controls.
10682 Available @code{location-access-controls} fields are:
10684 @deftypevr {@code{location-access-controls} parameter} file-name path
10685 Specifies the URI path to which the access control applies.
10688 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10689 Access controls for all access to this path, in the same format as the
10690 @code{access-controls} of @code{operation-access-control}.
10692 Defaults to @samp{()}.
10695 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10696 Access controls for method-specific access to this path.
10698 Defaults to @samp{()}.
10700 Available @code{method-access-controls} fields are:
10702 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10703 If @code{#t}, apply access controls to all methods except the listed
10704 methods. Otherwise apply to only the listed methods.
10706 Defaults to @samp{#f}.
10709 @deftypevr {@code{method-access-controls} parameter} method-list methods
10710 Methods to which this access control applies.
10712 Defaults to @samp{()}.
10715 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10716 Access control directives, as a list of strings. Each string should be
10717 one directive, such as "Order allow,deny".
10719 Defaults to @samp{()}.
10724 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10725 Specifies the number of debugging messages that are retained for logging
10726 if an error occurs in a print job. Debug messages are logged regardless
10727 of the LogLevel setting.
10729 Defaults to @samp{100}.
10732 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10733 Specifies the level of logging for the ErrorLog file. The value
10734 @code{none} stops all logging while @code{debug2} logs everything.
10736 Defaults to @samp{info}.
10739 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10740 Specifies the format of the date and time in the log files. The value
10741 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10743 Defaults to @samp{standard}.
10746 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10747 Specifies the maximum number of simultaneous clients that are allowed by
10750 Defaults to @samp{100}.
10753 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10754 Specifies the maximum number of simultaneous clients that are allowed
10755 from a single address.
10757 Defaults to @samp{100}.
10760 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10761 Specifies the maximum number of copies that a user can print of each
10764 Defaults to @samp{9999}.
10767 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10768 Specifies the maximum time a job may remain in the @code{indefinite}
10769 hold state before it is canceled. A value of 0 disables cancellation of
10772 Defaults to @samp{0}.
10775 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10776 Specifies the maximum number of simultaneous jobs that are allowed. Set
10777 to 0 to allow an unlimited number of jobs.
10779 Defaults to @samp{500}.
10782 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10783 Specifies the maximum number of simultaneous jobs that are allowed per
10784 printer. A value of 0 allows up to MaxJobs jobs per printer.
10786 Defaults to @samp{0}.
10789 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10790 Specifies the maximum number of simultaneous jobs that are allowed per
10791 user. A value of 0 allows up to MaxJobs jobs per user.
10793 Defaults to @samp{0}.
10796 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10797 Specifies the maximum time a job may take to print before it is
10798 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10800 Defaults to @samp{10800}.
10803 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10804 Specifies the maximum size of the log files before they are rotated, in
10805 bytes. The value 0 disables log rotation.
10807 Defaults to @samp{1048576}.
10810 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10811 Specifies the maximum amount of time to allow between files in a
10812 multiple file print job, in seconds.
10814 Defaults to @samp{300}.
10817 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10818 Specifies the format of PageLog lines. Sequences beginning with percent
10819 (@samp{%}) characters are replaced with the corresponding information,
10820 while all other characters are copied literally. The following percent
10821 sequences are recognized:
10825 insert a single percent character
10828 insert the value of the specified IPP attribute
10831 insert the number of copies for the current page
10834 insert the current page number
10837 insert the current date and time in common log format
10843 insert the printer name
10846 insert the username
10849 A value of the empty string disables page logging. The string @code{%p
10850 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10851 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10854 Defaults to @samp{""}.
10857 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10858 Passes the specified environment variable(s) to child processes; a list
10861 Defaults to @samp{()}.
10864 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10865 Specifies named access control policies.
10867 Available @code{policy-configuration} fields are:
10869 @deftypevr {@code{policy-configuration} parameter} string name
10870 Name of the policy.
10873 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10874 Specifies an access list for a job's private values. @code{@@ACL} maps
10875 to the printer's requesting-user-name-allowed or
10876 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10877 owner. @code{@@SYSTEM} maps to the groups listed for the
10878 @code{system-group} field of the @code{files-config} configuration,
10879 which is reified into the @code{cups-files.conf(5)} file. Other
10880 possible elements of the access list include specific user names, and
10881 @code{@@@var{group}} to indicate members of a specific group. The
10882 access list may also be simply @code{all} or @code{default}.
10884 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10887 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10888 Specifies the list of job values to make private, or @code{all},
10889 @code{default}, or @code{none}.
10891 Defaults to @samp{"job-name job-originating-host-name
10892 job-originating-user-name phone"}.
10895 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10896 Specifies an access list for a subscription's private values.
10897 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10898 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10899 owner. @code{@@SYSTEM} maps to the groups listed for the
10900 @code{system-group} field of the @code{files-config} configuration,
10901 which is reified into the @code{cups-files.conf(5)} file. Other
10902 possible elements of the access list include specific user names, and
10903 @code{@@@var{group}} to indicate members of a specific group. The
10904 access list may also be simply @code{all} or @code{default}.
10906 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10909 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
10910 Specifies the list of job values to make private, or @code{all},
10911 @code{default}, or @code{none}.
10913 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
10914 notify-subscriber-user-name notify-user-data"}.
10917 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
10918 Access control by IPP operation.
10920 Defaults to @samp{()}.
10924 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
10925 Specifies whether job files (documents) are preserved after a job is
10926 printed. If a numeric value is specified, job files are preserved for
10927 the indicated number of seconds after printing. Otherwise a boolean
10928 value applies indefinitely.
10930 Defaults to @samp{86400}.
10933 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
10934 Specifies whether the job history is preserved after a job is printed.
10935 If a numeric value is specified, the job history is preserved for the
10936 indicated number of seconds after printing. If @code{#t}, the job
10937 history is preserved until the MaxJobs limit is reached.
10939 Defaults to @samp{#t}.
10942 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
10943 Specifies the amount of time to wait for job completion before
10944 restarting the scheduler.
10946 Defaults to @samp{30}.
10949 @deftypevr {@code{cups-configuration} parameter} string rip-cache
10950 Specifies the maximum amount of memory to use when converting documents
10951 into bitmaps for a printer.
10953 Defaults to @samp{"128m"}.
10956 @deftypevr {@code{cups-configuration} parameter} string server-admin
10957 Specifies the email address of the server administrator.
10959 Defaults to @samp{"root@@localhost.localdomain"}.
10962 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
10963 The ServerAlias directive is used for HTTP Host header validation when
10964 clients connect to the scheduler from external interfaces. Using the
10965 special name @code{*} can expose your system to known browser-based DNS
10966 rebinding attacks, even when accessing sites through a firewall. If the
10967 auto-discovery of alternate names does not work, we recommend listing
10968 each alternate name with a ServerAlias directive instead of using
10971 Defaults to @samp{*}.
10974 @deftypevr {@code{cups-configuration} parameter} string server-name
10975 Specifies the fully-qualified host name of the server.
10977 Defaults to @samp{"localhost"}.
10980 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
10981 Specifies what information is included in the Server header of HTTP
10982 responses. @code{None} disables the Server header. @code{ProductOnly}
10983 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
10984 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
10985 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
10986 the output of the @code{uname} command. @code{Full} reports @code{CUPS
10987 2.0.0 (@var{uname}) IPP/2.0}.
10989 Defaults to @samp{Minimal}.
10992 @deftypevr {@code{cups-configuration} parameter} string set-env
10993 Set the specified environment variable to be passed to child processes.
10995 Defaults to @samp{"variable value"}.
10998 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
10999 Listens on the specified interfaces for encrypted connections. Valid
11000 values are of the form @var{address}:@var{port}, where @var{address} is
11001 either an IPv6 address enclosed in brackets, an IPv4 address, or
11002 @code{*} to indicate all addresses.
11004 Defaults to @samp{()}.
11007 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11008 Sets encryption options. By default, CUPS only supports encryption
11009 using TLS v1.0 or higher using known secure cipher suites. The
11010 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11011 required for some older clients that do not implement newer ones. The
11012 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11013 older clients that do not support TLS v1.0.
11015 Defaults to @samp{()}.
11018 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11019 Specifies whether the scheduler requires clients to strictly adhere to
11020 the IPP specifications.
11022 Defaults to @samp{#f}.
11025 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11026 Specifies the HTTP request timeout, in seconds.
11028 Defaults to @samp{300}.
11032 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11033 Specifies whether the web interface is enabled.
11035 Defaults to @samp{#f}.
11038 At this point you're probably thinking ``oh dear, Guix manual, I like
11039 you but you can stop already with the configuration options''. Indeed.
11040 However, one more point: it could be that you have an existing
11041 @code{cupsd.conf} that you want to use. In that case, you can pass an
11042 @code{opaque-cups-configuration} as the configuration of a
11043 @code{cups-service-type}.
11045 Available @code{opaque-cups-configuration} fields are:
11047 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11051 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11052 The contents of the @code{cupsd.conf}, as a string.
11055 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11056 The contents of the @code{cups-files.conf} file, as a string.
11059 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11060 strings of the same name, you could instantiate a CUPS service like
11064 (service cups-service-type
11065 (opaque-cups-configuration
11066 (cupsd.conf cupsd.conf)
11067 (cups-files.conf cups-files.conf)))
11071 @node Desktop Services
11072 @subsubsection Desktop Services
11074 The @code{(gnu services desktop)} module provides services that are
11075 usually useful in the context of a ``desktop'' setup---that is, on a
11076 machine running a graphical display server, possibly with graphical user
11077 interfaces, etc. It also defines services that provide specific desktop
11078 environments like GNOME and XFCE.
11080 To simplify things, the module defines a variable containing the set of
11081 services that users typically expect on a machine with a graphical
11082 environment and networking:
11084 @defvr {Scheme Variable} %desktop-services
11085 This is a list of services that builds upon @var{%base-services} and
11086 adds or adjusts services for a typical ``desktop'' setup.
11088 In particular, it adds a graphical login manager (@pxref{X Window,
11089 @code{slim-service}}), screen lockers,
11090 a network management tool (@pxref{Networking
11091 Services, @code{wicd-service}}), energy and color management services,
11092 the @code{elogind} login and seat manager, the Polkit privilege service,
11093 the GeoClue location service, an NTP client (@pxref{Networking
11094 Services}), the Avahi daemon, and has the name service switch service
11095 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11099 The @var{%desktop-services} variable can be used as the @code{services}
11100 field of an @code{operating-system} declaration (@pxref{operating-system
11101 Reference, @code{services}}).
11103 Additionally, the @code{gnome-desktop-service} and
11104 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11105 system. To ``add GNOME'' means that system-level services like the
11106 backlight adjustment helpers and the power management utilities are
11107 added to the system, extending @code{polkit} and @code{dbus}
11108 appropriately, allowing GNOME to operate with elevated privileges on a
11109 limited number of special-purpose system interfaces. Additionally,
11110 adding a service made by @code{gnome-desktop-service} adds the GNOME
11111 metapackage to the system profile. Likewise, adding the XFCE service
11112 not only adds the @code{xfce} metapackage to the system profile, but it
11113 also gives the Thunar file manager the ability to open a ``root-mode''
11114 file management window, if the user authenticates using the
11115 administrator's password via the standard polkit graphical interface.
11117 @deffn {Scheme Procedure} gnome-desktop-service
11118 Return a service that adds the @code{gnome} package to the system
11119 profile, and extends polkit with the actions from
11120 @code{gnome-settings-daemon}.
11123 @deffn {Scheme Procedure} xfce-desktop-service
11124 Return a service that adds the @code{xfce} package to the system profile,
11125 and extends polkit with the ability for @code{thunar} to manipulate the
11126 file system as root from within a user session, after the user has
11127 authenticated with the administrator's password.
11130 Because the GNOME and XFCE desktop services pull in so many packages,
11131 the default @code{%desktop-services} variable doesn't include either of
11132 them by default. To add GNOME or XFCE, just @code{cons} them onto
11133 @code{%desktop-services} in the @code{services} field of your
11134 @code{operating-system}:
11137 (use-modules (gnu))
11138 (use-service-modules desktop)
11141 ;; cons* adds items to the list given as its last argument.
11142 (services (cons* (gnome-desktop-service)
11143 (xfce-desktop-service)
11144 %desktop-services))
11148 These desktop environments will then be available as options in the
11149 graphical login window.
11151 The actual service definitions included in @code{%desktop-services} and
11152 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11153 are described below.
11155 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11156 Return a service that runs the ``system bus'', using @var{dbus}, with
11157 support for @var{services}.
11159 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11160 facility. Its system bus is used to allow system services to communicate
11161 and to be notified of system-wide events.
11163 @var{services} must be a list of packages that provide an
11164 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11165 and policy files. For example, to allow avahi-daemon to use the system bus,
11166 @var{services} must be equal to @code{(list avahi)}.
11169 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11170 Return a service that runs the @code{elogind} login and
11171 seat management daemon. @uref{https://github.com/andywingo/elogind,
11172 Elogind} exposes a D-Bus interface that can be used to know which users
11173 are logged in, know what kind of sessions they have open, suspend the
11174 system, inhibit system suspend, reboot the system, and other tasks.
11176 Elogind handles most system-level power events for a computer, for
11177 example suspending the system when a lid is closed, or shutting it down
11178 when the power button is pressed.
11180 The @var{config} keyword argument specifies the configuration for
11181 elogind, and should be the result of an @code{(elogind-configuration
11182 (@var{parameter} @var{value})...)} invocation. Available parameters and
11183 their default values are:
11186 @item kill-user-processes?
11188 @item kill-only-users
11190 @item kill-exclude-users
11192 @item inhibit-delay-max-seconds
11194 @item handle-power-key
11196 @item handle-suspend-key
11198 @item handle-hibernate-key
11200 @item handle-lid-switch
11202 @item handle-lid-switch-docked
11204 @item power-key-ignore-inhibited?
11206 @item suspend-key-ignore-inhibited?
11208 @item hibernate-key-ignore-inhibited?
11210 @item lid-switch-ignore-inhibited?
11212 @item holdoff-timeout-seconds
11216 @item idle-action-seconds
11218 @item runtime-directory-size-percent
11220 @item runtime-directory-size
11224 @item suspend-state
11225 @code{("mem" "standby" "freeze")}
11228 @item hibernate-state
11230 @item hibernate-mode
11231 @code{("platform" "shutdown")}
11232 @item hybrid-sleep-state
11234 @item hybrid-sleep-mode
11235 @code{("suspend" "platform" "shutdown")}
11239 @deffn {Scheme Procedure} polkit-service @
11240 [#:polkit @var{polkit}]
11241 Return a service that runs the
11242 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11243 management service}, which allows system administrators to grant access to
11244 privileged operations in a structured way. By querying the Polkit service, a
11245 privileged system component can know when it should grant additional
11246 capabilities to ordinary users. For example, an ordinary user can be granted
11247 the capability to suspend the system if the user is logged in locally.
11250 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11251 [#:watts-up-pro? #f] @
11252 [#:poll-batteries? #t] @
11253 [#:ignore-lid? #f] @
11254 [#:use-percentage-for-policy? #f] @
11255 [#:percentage-low 10] @
11256 [#:percentage-critical 3] @
11257 [#:percentage-action 2] @
11258 [#:time-low 1200] @
11259 [#:time-critical 300] @
11260 [#:time-action 120] @
11261 [#:critical-power-action 'hybrid-sleep]
11262 Return a service that runs @uref{http://upower.freedesktop.org/,
11263 @command{upowerd}}, a system-wide monitor for power consumption and battery
11264 levels, with the given configuration settings. It implements the
11265 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11269 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11270 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11271 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11272 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11273 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11276 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11277 Return a service that runs @command{colord}, a system service with a D-Bus
11278 interface to manage the color profiles of input and output devices such as
11279 screens and scanners. It is notably used by the GNOME Color Manager graphical
11280 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11281 site} for more information.
11284 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11285 Return a configuration allowing an application to access GeoClue
11286 location data. @var{name} is the Desktop ID of the application, without
11287 the @code{.desktop} part. If @var{allowed?} is true, the application
11288 will have access to location information by default. The boolean
11289 @var{system?} value indicates whether an application is a system component
11290 or not. Finally @var{users} is a list of UIDs of all users for which
11291 this application is allowed location info access. An empty users list
11292 means that all users are allowed.
11295 @defvr {Scheme Variable} %standard-geoclue-applications
11296 The standard list of well-known GeoClue application configurations,
11297 granting authority to the GNOME date-and-time utility to ask for the
11298 current location in order to set the time zone, and allowing the
11299 IceCat and Epiphany web browsers to request location information.
11300 IceCat and Epiphany both query the user before allowing a web page to
11301 know the user's location.
11304 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11305 [#:whitelist '()] @
11306 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11307 [#:submit-data? #f]
11308 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11309 [#:submission-nick "geoclue"] @
11310 [#:applications %standard-geoclue-applications]
11311 Return a service that runs the GeoClue location service. This service
11312 provides a D-Bus interface to allow applications to request access to a
11313 user's physical location, and optionally to add information to online
11314 location databases. See
11315 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11316 web site} for more information.
11319 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11320 Return a service that runs the @command{bluetoothd} daemon, which manages
11321 all the Bluetooth devices and provides a number of D-Bus interfaces.
11323 Users need to be in the @code{lp} group to access the D-Bus service.
11326 @node Database Services
11327 @subsubsection Database Services
11331 The @code{(gnu services databases)} module provides the following services.
11333 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11334 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11335 [#:port 5432] [#:locale ``en_US.utf8'']
11336 Return a service that runs @var{postgresql}, the PostgreSQL database
11339 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11340 creates a database cluster with @var{locale} as the default
11341 locale, stored in @var{data-directory}. It then listens on @var{port}.
11344 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11345 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11348 The optional @var{config} argument specifies the configuration for
11349 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11352 @deftp {Data Type} mysql-configuration
11353 Data type representing the configuration of @var{mysql-service}.
11356 @item @code{mysql} (default: @var{mariadb})
11357 Package object of the MySQL database server, can be either @var{mariadb}
11360 For MySQL, a temporary root password will be displayed at activation time.
11361 For MariaDB, the root password is empty.
11363 @item @code{port} (default: @code{3306})
11364 TCP port on which the database server listens for incoming connections.
11368 @defvr {Scheme Variable} redis-service-type
11369 This is the service type for the @uref{https://redis.io/, Redis}
11370 key/value store, whose value is a @code{redis-configuration} object.
11373 @deftp {Data Type} redis-configuration
11374 Data type representing the configuration of redis.
11377 @item @code{redis} (default: @code{redis})
11378 The Redis package to use.
11380 @item @code{bind} (default: @code{"127.0.0.1"})
11381 Network interface on which to listen.
11383 @item @code{port} (default: @code{6379})
11384 Port on which to accept connections on, a value of 0 will disable
11385 listening on a TCP socket.
11387 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11388 Directory in which to store the database and related files.
11392 @node Mail Services
11393 @subsubsection Mail Services
11397 The @code{(gnu services mail)} module provides Guix service definitions
11398 for email services: IMAP, POP3, and LMTP servers, as well as mail
11399 transport agents (MTAs). Lots of acronyms! These services are detailed
11400 in the subsections below.
11402 @subsubheading Dovecot Service
11404 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11405 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11408 By default, Dovecot does not need much configuration; the default
11409 configuration object created by @code{(dovecot-configuration)} will
11410 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11411 certificate will be generated for TLS-protected connections, though
11412 Dovecot will also listen on cleartext ports by default. There are a
11413 number of options, though, which mail administrators might need to change,
11414 and as is the case with other services, Guix allows the system
11415 administrator to specify these parameters via a uniform Scheme interface.
11417 For example, to specify that mail is located at @code{maildir~/.mail},
11418 one would instantiate the Dovecot service like this:
11421 (dovecot-service #:config
11422 (dovecot-configuration
11423 (mail-location "maildir:~/.mail")))
11426 The available configuration parameters follow. Each parameter
11427 definition is preceded by its type; for example, @samp{string-list foo}
11428 indicates that the @code{foo} parameter should be specified as a list of
11429 strings. There is also a way to specify the configuration as a string,
11430 if you have an old @code{dovecot.conf} file that you want to port over
11431 from some other system; see the end for more details.
11433 @c The following documentation was initially generated by
11434 @c (generate-documentation) in (gnu services mail). Manually maintained
11435 @c documentation is better, so we shouldn't hesitate to edit below as
11436 @c needed. However if the change you want to make to this documentation
11437 @c can be done in an automated way, it's probably easier to change
11438 @c (generate-documentation) than to make it below and have to deal with
11439 @c the churn as dovecot updates.
11441 Available @code{dovecot-configuration} fields are:
11443 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11444 The dovecot package.
11447 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11448 A list of IPs or hosts where to listen for connections. @samp{*}
11449 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11450 interfaces. If you want to specify non-default ports or anything more
11451 complex, customize the address and port fields of the
11452 @samp{inet-listener} of the specific services you are interested in.
11455 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11456 List of protocols we want to serve. Available protocols include
11457 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11459 Available @code{protocol-configuration} fields are:
11461 @deftypevr {@code{protocol-configuration} parameter} string name
11462 The name of the protocol.
11465 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11466 UNIX socket path to the master authentication server to find users.
11467 This is used by imap (for shared users) and lda.
11468 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11471 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11472 Space separated list of plugins to load.
11475 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11476 Maximum number of IMAP connections allowed for a user from each IP
11477 address. NOTE: The username is compared case-sensitively.
11478 Defaults to @samp{10}.
11483 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11484 List of services to enable. Available services include @samp{imap},
11485 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11488 Available @code{service-configuration} fields are:
11490 @deftypevr {@code{service-configuration} parameter} string kind
11491 The service kind. Valid values include @code{director},
11492 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11493 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11494 @code{tcpwrap}, @code{quota-warning}, or anything else.
11497 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11498 Listeners for the service. A listener is either a
11499 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11500 an @code{inet-listener-configuration}.
11501 Defaults to @samp{()}.
11503 Available @code{unix-listener-configuration} fields are:
11505 @deftypevr {@code{unix-listener-configuration} parameter} string path
11506 Path to the file, relative to @code{base-dir} field. This is also used as
11510 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11511 The access mode for the socket.
11512 Defaults to @samp{"0600"}.
11515 @deftypevr {@code{unix-listener-configuration} parameter} string user
11516 The user to own the socket.
11517 Defaults to @samp{""}.
11520 @deftypevr {@code{unix-listener-configuration} parameter} string group
11521 The group to own the socket.
11522 Defaults to @samp{""}.
11526 Available @code{fifo-listener-configuration} fields are:
11528 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11529 Path to the file, relative to @code{base-dir} field. This is also used as
11533 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11534 The access mode for the socket.
11535 Defaults to @samp{"0600"}.
11538 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11539 The user to own the socket.
11540 Defaults to @samp{""}.
11543 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11544 The group to own the socket.
11545 Defaults to @samp{""}.
11549 Available @code{inet-listener-configuration} fields are:
11551 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11552 The protocol to listen for.
11555 @deftypevr {@code{inet-listener-configuration} parameter} string address
11556 The address on which to listen, or empty for all addresses.
11557 Defaults to @samp{""}.
11560 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11561 The port on which to listen.
11564 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11565 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11567 Defaults to @samp{#t}.
11572 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11573 Number of connections to handle before starting a new process.
11574 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11575 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11576 Defaults to @samp{1}.
11579 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11580 Number of processes to always keep waiting for more connections.
11581 Defaults to @samp{0}.
11584 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11585 If you set @samp{service-count 0}, you probably need to grow
11587 Defaults to @samp{256000000}.
11592 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11593 Dict configuration, as created by the @code{dict-configuration}
11596 Available @code{dict-configuration} fields are:
11598 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11599 A list of key-value pairs that this dict should hold.
11600 Defaults to @samp{()}.
11605 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11606 A list of passdb configurations, each one created by the
11607 @code{passdb-configuration} constructor.
11609 Available @code{passdb-configuration} fields are:
11611 @deftypevr {@code{passdb-configuration} parameter} string driver
11612 The driver that the passdb should use. Valid values include
11613 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11615 Defaults to @samp{"pam"}.
11618 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11619 Space separated list of arguments to the passdb driver.
11620 Defaults to @samp{""}.
11625 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11626 List of userdb configurations, each one created by the
11627 @code{userdb-configuration} constructor.
11629 Available @code{userdb-configuration} fields are:
11631 @deftypevr {@code{userdb-configuration} parameter} string driver
11632 The driver that the userdb should use. Valid values include
11633 @samp{passwd} and @samp{static}.
11634 Defaults to @samp{"passwd"}.
11637 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11638 Space separated list of arguments to the userdb driver.
11639 Defaults to @samp{""}.
11642 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11643 Override fields from passwd.
11644 Defaults to @samp{()}.
11649 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11650 Plug-in configuration, created by the @code{plugin-configuration}
11654 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11655 List of namespaces. Each item in the list is created by the
11656 @code{namespace-configuration} constructor.
11658 Available @code{namespace-configuration} fields are:
11660 @deftypevr {@code{namespace-configuration} parameter} string name
11661 Name for this namespace.
11664 @deftypevr {@code{namespace-configuration} parameter} string type
11665 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11666 Defaults to @samp{"private"}.
11669 @deftypevr {@code{namespace-configuration} parameter} string separator
11670 Hierarchy separator to use. You should use the same separator for
11671 all namespaces or some clients get confused. @samp{/} is usually a good
11672 one. The default however depends on the underlying mail storage
11674 Defaults to @samp{""}.
11677 @deftypevr {@code{namespace-configuration} parameter} string prefix
11678 Prefix required to access this namespace. This needs to be
11679 different for all namespaces. For example @samp{Public/}.
11680 Defaults to @samp{""}.
11683 @deftypevr {@code{namespace-configuration} parameter} string location
11684 Physical location of the mailbox. This is in the same format as
11685 mail_location, which is also the default for it.
11686 Defaults to @samp{""}.
11689 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11690 There can be only one INBOX, and this setting defines which
11692 Defaults to @samp{#f}.
11695 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11696 If namespace is hidden, it's not advertised to clients via NAMESPACE
11697 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11698 useful when converting from another server with different namespaces
11699 which you want to deprecate but still keep working. For example you can
11700 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11702 Defaults to @samp{#f}.
11705 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11706 Show the mailboxes under this namespace with the LIST command. This
11707 makes the namespace visible for clients that do not support the NAMESPACE
11708 extension. The special @code{children} value lists child mailboxes, but
11709 hides the namespace prefix.
11710 Defaults to @samp{#t}.
11713 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11714 Namespace handles its own subscriptions. If set to @code{#f}, the
11715 parent namespace handles them. The empty prefix should always have this
11717 Defaults to @samp{#t}.
11720 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11721 List of predefined mailboxes in this namespace.
11722 Defaults to @samp{()}.
11724 Available @code{mailbox-configuration} fields are:
11726 @deftypevr {@code{mailbox-configuration} parameter} string name
11727 Name for this mailbox.
11730 @deftypevr {@code{mailbox-configuration} parameter} string auto
11731 @samp{create} will automatically create this mailbox.
11732 @samp{subscribe} will both create and subscribe to the mailbox.
11733 Defaults to @samp{"no"}.
11736 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11737 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11738 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11739 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11740 Defaults to @samp{()}.
11747 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11748 Base directory where to store runtime data.
11749 Defaults to @samp{"/var/run/dovecot/"}.
11752 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11753 Greeting message for clients.
11754 Defaults to @samp{"Dovecot ready."}.
11757 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11758 List of trusted network ranges. Connections from these IPs are
11759 allowed to override their IP addresses and ports (for logging and for
11760 authentication checks). @samp{disable-plaintext-auth} is also ignored
11761 for these networks. Typically you would specify your IMAP proxy servers
11763 Defaults to @samp{()}.
11766 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11767 List of login access check sockets (e.g. tcpwrap).
11768 Defaults to @samp{()}.
11771 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11772 Show more verbose process titles (in ps). Currently shows user name
11773 and IP address. Useful for seeing who is actually using the IMAP
11774 processes (e.g. shared mailboxes or if the same uid is used for multiple
11776 Defaults to @samp{#f}.
11779 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11780 Should all processes be killed when Dovecot master process shuts down.
11781 Setting this to @code{#f} means that Dovecot can be upgraded without
11782 forcing existing client connections to close (although that could also
11783 be a problem if the upgrade is e.g. due to a security fix).
11784 Defaults to @samp{#t}.
11787 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11788 If non-zero, run mail commands via this many connections to doveadm
11789 server, instead of running them directly in the same process.
11790 Defaults to @samp{0}.
11793 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11794 UNIX socket or host:port used for connecting to doveadm server.
11795 Defaults to @samp{"doveadm-server"}.
11798 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11799 List of environment variables that are preserved on Dovecot startup
11800 and passed down to all of its child processes. You can also give
11801 key=value pairs to always set specific settings.
11804 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11805 Disable LOGIN command and all other plaintext authentications unless
11806 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11807 matches the local IP (i.e. you're connecting from the same computer),
11808 the connection is considered secure and plaintext authentication is
11809 allowed. See also ssl=required setting.
11810 Defaults to @samp{#t}.
11813 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11814 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11815 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11816 for caching to be used.
11817 Defaults to @samp{0}.
11820 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11821 Time to live for cached data. After TTL expires the cached record
11822 is no longer used, *except* if the main database lookup returns internal
11823 failure. We also try to handle password changes automatically: If
11824 user's previous authentication was successful, but this one wasn't, the
11825 cache isn't used. For now this works only with plaintext
11827 Defaults to @samp{"1 hour"}.
11830 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11831 TTL for negative hits (user not found, password mismatch).
11832 0 disables caching them completely.
11833 Defaults to @samp{"1 hour"}.
11836 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11837 List of realms for SASL authentication mechanisms that need them.
11838 You can leave it empty if you don't want to support multiple realms.
11839 Many clients simply use the first one listed here, so keep the default
11841 Defaults to @samp{()}.
11844 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11845 Default realm/domain to use if none was specified. This is used for
11846 both SASL realms and appending @@domain to username in plaintext
11848 Defaults to @samp{""}.
11851 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11852 List of allowed characters in username. If the user-given username
11853 contains a character not listed in here, the login automatically fails.
11854 This is just an extra check to make sure user can't exploit any
11855 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11856 you want to allow all characters, set this value to empty.
11857 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11860 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11861 Username character translations before it's looked up from
11862 databases. The value contains series of from -> to characters. For
11863 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11864 translated to @samp{@@}.
11865 Defaults to @samp{""}.
11868 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11869 Username formatting before it's looked up from databases. You can
11870 use the standard variables here, e.g. %Lu would lowercase the username,
11871 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11872 change the @samp{@@} into @samp{-AT-}. This translation is done after
11873 @samp{auth-username-translation} changes.
11874 Defaults to @samp{"%Lu"}.
11877 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11878 If you want to allow master users to log in by specifying the master
11879 username within the normal username string (i.e. not using SASL
11880 mechanism's support for it), you can specify the separator character
11881 here. The format is then <username><separator><master username>.
11882 UW-IMAP uses @samp{*} as the separator, so that could be a good
11884 Defaults to @samp{""}.
11887 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11888 Username to use for users logging in with ANONYMOUS SASL
11890 Defaults to @samp{"anonymous"}.
11893 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11894 Maximum number of dovecot-auth worker processes. They're used to
11895 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11896 They're automatically created and destroyed as needed.
11897 Defaults to @samp{30}.
11900 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11901 Host name to use in GSSAPI principal names. The default is to use
11902 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
11903 allow all keytab entries.
11904 Defaults to @samp{""}.
11907 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
11908 Kerberos keytab to use for the GSSAPI mechanism. Will use the
11909 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
11910 need to change the auth service to run as root to be able to read this
11912 Defaults to @samp{""}.
11915 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
11916 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
11917 and @samp{ntlm-auth} helper.
11918 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
11919 Defaults to @samp{#f}.
11922 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
11923 Path for Samba's @samp{ntlm-auth} helper binary.
11924 Defaults to @samp{"/usr/bin/ntlm_auth"}.
11927 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
11928 Time to delay before replying to failed authentications.
11929 Defaults to @samp{"2 secs"}.
11932 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
11933 Require a valid SSL client certificate or the authentication
11935 Defaults to @samp{#f}.
11938 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
11939 Take the username from client's SSL certificate, using
11940 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
11942 Defaults to @samp{#f}.
11945 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
11946 List of wanted authentication mechanisms. Supported mechanisms are:
11947 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
11948 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
11949 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
11950 @samp{disable-plaintext-auth} setting.
11953 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
11954 List of IPs or hostnames to all director servers, including ourself.
11955 Ports can be specified as ip:port. The default port is the same as what
11956 director service's @samp{inet-listener} is using.
11957 Defaults to @samp{()}.
11960 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
11961 List of IPs or hostnames to all backend mail servers. Ranges are
11962 allowed too, like 10.0.0.10-10.0.0.30.
11963 Defaults to @samp{()}.
11966 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
11967 How long to redirect users to a specific server after it no longer
11968 has any connections.
11969 Defaults to @samp{"15 min"}.
11972 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
11973 TCP/IP port that accepts doveadm connections (instead of director
11974 connections) If you enable this, you'll also need to add
11975 @samp{inet-listener} for the port.
11976 Defaults to @samp{0}.
11979 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
11980 How the username is translated before being hashed. Useful values
11981 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
11982 are shared within domain.
11983 Defaults to @samp{"%Lu"}.
11986 @deftypevr {@code{dovecot-configuration} parameter} string log-path
11987 Log file to use for error messages. @samp{syslog} logs to syslog,
11988 @samp{/dev/stderr} logs to stderr.
11989 Defaults to @samp{"syslog"}.
11992 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
11993 Log file to use for informational messages. Defaults to
11995 Defaults to @samp{""}.
11998 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
11999 Log file to use for debug messages. Defaults to
12000 @samp{info-log-path}.
12001 Defaults to @samp{""}.
12004 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12005 Syslog facility to use if you're logging to syslog. Usually if you
12006 don't want to use @samp{mail}, you'll use local0..local7. Also other
12007 standard facilities are supported.
12008 Defaults to @samp{"mail"}.
12011 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12012 Log unsuccessful authentication attempts and the reasons why they
12014 Defaults to @samp{#f}.
12017 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12018 In case of password mismatches, log the attempted password. Valid
12019 values are no, plain and sha1. sha1 can be useful for detecting brute
12020 force password attempts vs. user simply trying the same password over
12021 and over again. You can also truncate the value to n chars by appending
12022 ":n" (e.g. sha1:6).
12023 Defaults to @samp{#f}.
12026 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12027 Even more verbose logging for debugging purposes. Shows for example
12029 Defaults to @samp{#f}.
12032 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12033 In case of password mismatches, log the passwords and used scheme so
12034 the problem can be debugged. Enabling this also enables
12036 Defaults to @samp{#f}.
12039 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12040 Enable mail process debugging. This can help you figure out why
12041 Dovecot isn't finding your mails.
12042 Defaults to @samp{#f}.
12045 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12046 Show protocol level SSL errors.
12047 Defaults to @samp{#f}.
12050 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12051 Prefix for each line written to log file. % codes are in
12052 strftime(3) format.
12053 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12056 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12057 List of elements we want to log. The elements which have a
12058 non-empty variable value are joined together to form a comma-separated
12062 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12063 Login log format. %s contains @samp{login-log-format-elements}
12064 string, %$ contains the data we want to log.
12065 Defaults to @samp{"%$: %s"}.
12068 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12069 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12070 of possible variables you can use.
12071 Defaults to @samp{"\"%s(%u): \""}.
12074 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12075 Format to use for logging mail deliveries. You can use variables:
12078 Delivery status message (e.g. @samp{saved to INBOX})
12090 Defaults to @samp{"msgid=%m: %$"}.
12093 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12094 Location for users' mailboxes. The default is empty, which means
12095 that Dovecot tries to find the mailboxes automatically. This won't work
12096 if the user doesn't yet have any mail, so you should explicitly tell
12097 Dovecot the full location.
12099 If you're using mbox, giving a path to the INBOX
12100 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12101 where the other mailboxes are kept. This is called the "root mail
12102 directory", and it must be the first path given in the
12103 @samp{mail-location} setting.
12105 There are a few special variables you can use, eg.:
12111 user part in user@@domain, same as %u if there's no domain
12113 domain part in user@@domain, empty if there's no domain
12118 See doc/wiki/Variables.txt for full list. Some examples:
12120 @item maildir:~/Maildir
12121 @item mbox:~/mail:INBOX=/var/mail/%u
12122 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12124 Defaults to @samp{""}.
12127 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12128 System user and group used to access mails. If you use multiple,
12129 userdb can override these by returning uid or gid fields. You can use
12130 either numbers or names. <doc/wiki/UserIds.txt>.
12131 Defaults to @samp{""}.
12134 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12136 Defaults to @samp{""}.
12139 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12140 Group to enable temporarily for privileged operations. Currently
12141 this is used only with INBOX when either its initial creation or
12142 dotlocking fails. Typically this is set to "mail" to give access to
12144 Defaults to @samp{""}.
12147 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12148 Grant access to these supplementary groups for mail processes.
12149 Typically these are used to set up access to shared mailboxes. Note
12150 that it may be dangerous to set these if users can create
12151 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12152 could allow a user to delete others' mailboxes, or ln -s
12153 /secret/shared/box ~/mail/mybox would allow reading it).
12154 Defaults to @samp{""}.
12157 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12158 Allow full file system access to clients. There's no access checks
12159 other than what the operating system does for the active UID/GID. It
12160 works with both maildir and mboxes, allowing you to prefix mailboxes
12161 names with e.g. /path/ or ~user/.
12162 Defaults to @samp{#f}.
12165 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12166 Don't use mmap() at all. This is required if you store indexes to
12167 shared file systems (NFS or clustered file system).
12168 Defaults to @samp{#f}.
12171 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12172 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12173 supports @samp{O_EXCL} since version 3, so this should be safe to use
12174 nowadays by default.
12175 Defaults to @samp{#t}.
12178 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12179 When to use fsync() or fdatasync() calls:
12182 Whenever necessary to avoid losing important data
12184 Useful with e.g. NFS when write()s are delayed
12186 Never use it (best performance, but crashes can lose data).
12188 Defaults to @samp{"optimized"}.
12191 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12192 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12193 NFS caches whenever needed. If you're using only a single mail server
12195 Defaults to @samp{#f}.
12198 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12199 Mail index files also exist in NFS. Setting this to yes requires
12200 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12201 Defaults to @samp{#f}.
12204 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12205 Locking method for index files. Alternatives are fcntl, flock and
12206 dotlock. Dotlocking uses some tricks which may create more disk I/O
12207 than other locking methods. NFS users: flock doesn't work, remember to
12208 change @samp{mmap-disable}.
12209 Defaults to @samp{"fcntl"}.
12212 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12213 Directory in which LDA/LMTP temporarily stores incoming mails >128
12215 Defaults to @samp{"/tmp"}.
12218 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12219 Valid UID range for users. This is mostly to make sure that users can't
12220 log in as daemons or other system users. Note that denying root logins is
12221 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12223 Defaults to @samp{500}.
12226 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12228 Defaults to @samp{0}.
12231 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12232 Valid GID range for users. Users having non-valid GID as primary group ID
12233 aren't allowed to log in. If user belongs to supplementary groups with
12234 non-valid GIDs, those groups are not set.
12235 Defaults to @samp{1}.
12238 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12240 Defaults to @samp{0}.
12243 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12244 Maximum allowed length for mail keyword name. It's only forced when
12245 trying to create new keywords.
12246 Defaults to @samp{50}.
12249 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12250 List of directories under which chrooting is allowed for mail
12251 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12252 too). This setting doesn't affect @samp{login-chroot}
12253 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12254 "/./" in home dirs are ignored. WARNING: Never add directories here
12255 which local users can modify, that may lead to root exploit. Usually
12256 this should be done only if you don't allow shell access for users.
12257 <doc/wiki/Chrooting.txt>.
12258 Defaults to @samp{()}.
12261 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12262 Default chroot directory for mail processes. This can be overridden
12263 for specific users in user database by giving /./ in user's home
12264 directory (e.g. /home/./user chroots into /home). Note that usually
12265 there is no real need to do chrooting, Dovecot doesn't allow users to
12266 access files outside their mail directory anyway. If your home
12267 directories are prefixed with the chroot directory, append "/." to
12268 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12269 Defaults to @samp{""}.
12272 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12273 UNIX socket path to master authentication server to find users.
12274 This is used by imap (for shared users) and lda.
12275 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12278 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12279 Directory where to look up mail plugins.
12280 Defaults to @samp{"/usr/lib/dovecot"}.
12283 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12284 List of plugins to load for all services. Plugins specific to IMAP,
12285 LDA, etc. are added to this list in their own .conf files.
12286 Defaults to @samp{()}.
12289 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12290 The minimum number of mails in a mailbox before updates are done to
12291 cache file. This allows optimizing Dovecot's behavior to do less disk
12292 writes at the cost of more disk reads.
12293 Defaults to @samp{0}.
12296 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12297 When IDLE command is running, mailbox is checked once in a while to
12298 see if there are any new mails or other changes. This setting defines
12299 the minimum time to wait between those checks. Dovecot can also use
12300 dnotify, inotify and kqueue to find out immediately when changes
12302 Defaults to @samp{"30 secs"}.
12305 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12306 Save mails with CR+LF instead of plain LF. This makes sending those
12307 mails take less CPU, especially with sendfile() syscall with Linux and
12308 FreeBSD. But it also creates a bit more disk I/O which may just make it
12309 slower. Also note that if other software reads the mboxes/maildirs,
12310 they may handle the extra CRs wrong and cause problems.
12311 Defaults to @samp{#f}.
12314 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12315 By default LIST command returns all entries in maildir beginning
12316 with a dot. Enabling this option makes Dovecot return only entries
12317 which are directories. This is done by stat()ing each entry, so it
12318 causes more disk I/O.
12319 (For systems setting struct @samp{dirent->d_type} this check is free
12320 and it's done always regardless of this setting).
12321 Defaults to @samp{#f}.
12324 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12325 When copying a message, do it with hard links whenever possible.
12326 This makes the performance much better, and it's unlikely to have any
12328 Defaults to @samp{#t}.
12331 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12332 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12333 directory only when its mtime changes unexpectedly or when we can't find
12334 the mail otherwise.
12335 Defaults to @samp{#f}.
12338 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12339 Which locking methods to use for locking mbox. There are four
12344 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12345 solution. If you want to use /var/mail/ like directory, the users will
12346 need write access to that directory.
12348 Same as dotlock, but if it fails because of permissions or because there
12349 isn't enough disk space, just skip it.
12351 Use this if possible. Works with NFS too if lockd is used.
12353 May not exist in all systems. Doesn't work with NFS.
12355 May not exist in all systems. Doesn't work with NFS.
12358 You can use multiple locking methods; if you do the order they're declared
12359 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12360 locking methods as well. Some operating systems don't allow using some of
12361 them simultaneously.
12364 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12368 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12369 Maximum time to wait for lock (all of them) before aborting.
12370 Defaults to @samp{"5 mins"}.
12373 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12374 If dotlock exists but the mailbox isn't modified in any way,
12375 override the lock file after this much time.
12376 Defaults to @samp{"2 mins"}.
12379 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12380 When mbox changes unexpectedly we have to fully read it to find out
12381 what changed. If the mbox is large this can take a long time. Since
12382 the change is usually just a newly appended mail, it'd be faster to
12383 simply read the new mails. If this setting is enabled, Dovecot does
12384 this but still safely fallbacks to re-reading the whole mbox file
12385 whenever something in mbox isn't how it's expected to be. The only real
12386 downside to this setting is that if some other MUA changes message
12387 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12388 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12389 Defaults to @samp{#t}.
12392 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12393 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12394 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12395 @samp{mbox-dirty-syncs} is ignored.
12396 Defaults to @samp{#f}.
12399 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12400 Delay writing mbox headers until doing a full write sync (EXPUNGE
12401 and CHECK commands and when closing the mailbox). This is especially
12402 useful for POP3 where clients often delete all mails. The downside is
12403 that our changes aren't immediately visible to other MUAs.
12404 Defaults to @samp{#t}.
12407 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12408 If mbox size is smaller than this (e.g. 100k), don't write index
12409 files. If an index file already exists it's still read, just not
12411 Defaults to @samp{0}.
12414 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12415 Maximum dbox file size until it's rotated.
12416 Defaults to @samp{2000000}.
12419 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12420 Maximum dbox file age until it's rotated. Typically in days. Day
12421 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12423 Defaults to @samp{"1d"}.
12426 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12427 When creating new mdbox files, immediately preallocate their size to
12428 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12429 with some file systems (ext4, xfs).
12430 Defaults to @samp{#f}.
12433 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12434 sdbox and mdbox support saving mail attachments to external files,
12435 which also allows single instance storage for them. Other backends
12436 don't support this for now.
12438 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12440 Directory root where to store mail attachments. Disabled, if empty.
12441 Defaults to @samp{""}.
12444 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12445 Attachments smaller than this aren't saved externally. It's also
12446 possible to write a plugin to disable saving specific attachments
12448 Defaults to @samp{128000}.
12451 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12452 File system backend to use for saving attachments:
12455 No SiS done by Dovecot (but this might help FS's own deduplication)
12457 SiS with immediate byte-by-byte comparison during saving
12458 @item sis-queue posix
12459 SiS with delayed comparison and deduplication.
12461 Defaults to @samp{"sis posix"}.
12464 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12465 Hash format to use in attachment filenames. You can add any text and
12466 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12467 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12468 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12469 Defaults to @samp{"%@{sha1@}"}.
12472 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12474 Defaults to @samp{100}.
12477 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12479 Defaults to @samp{1000}.
12482 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12483 Default VSZ (virtual memory size) limit for service processes.
12484 This is mainly intended to catch and kill processes that leak memory
12485 before they eat up everything.
12486 Defaults to @samp{256000000}.
12489 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12490 Login user is internally used by login processes. This is the most
12491 untrusted user in Dovecot system. It shouldn't have access to anything
12493 Defaults to @samp{"dovenull"}.
12496 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12497 Internal user is used by unprivileged processes. It should be
12498 separate from login user, so that login processes can't disturb other
12500 Defaults to @samp{"dovecot"}.
12503 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12504 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12505 Defaults to @samp{"required"}.
12508 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12509 PEM encoded X.509 SSL/TLS certificate (public key).
12510 Defaults to @samp{"</etc/dovecot/default.pem"}.
12513 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12514 PEM encoded SSL/TLS private key. The key is opened before
12515 dropping root privileges, so keep the key file unreadable by anyone but
12517 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12520 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12521 If key file is password protected, give the password here.
12522 Alternatively give it when starting dovecot with -p parameter. Since
12523 this file is often world-readable, you may want to place this setting
12524 instead to a different.
12525 Defaults to @samp{""}.
12528 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12529 PEM encoded trusted certificate authority. Set this only if you
12530 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12531 contain the CA certificate(s) followed by the matching
12532 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12533 Defaults to @samp{""}.
12536 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12537 Require that CRL check succeeds for client certificates.
12538 Defaults to @samp{#t}.
12541 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12542 Request client to send a certificate. If you also want to require
12543 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12544 Defaults to @samp{#f}.
12547 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12548 Which field from certificate to use for username. commonName and
12549 x500UniqueIdentifier are the usual choices. You'll also need to set
12550 @samp{auth-ssl-username-from-cert? #t}.
12551 Defaults to @samp{"commonName"}.
12554 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12555 How often to regenerate the SSL parameters file. Generation is
12556 quite CPU intensive operation. The value is in hours, 0 disables
12557 regeneration entirely.
12558 Defaults to @samp{168}.
12561 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12562 SSL protocols to use.
12563 Defaults to @samp{"!SSLv2"}.
12566 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12567 SSL ciphers to use.
12568 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12571 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12572 SSL crypto device to use, for valid values run "openssl engine".
12573 Defaults to @samp{""}.
12576 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12577 Address to use when sending rejection mails.
12578 %d expands to recipient domain.
12579 Defaults to @samp{"postmaster@@%d"}.
12582 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12583 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12584 and in LMTP replies. Default is the system's real hostname@@domain.
12585 Defaults to @samp{""}.
12588 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12589 If user is over quota, return with temporary failure instead of
12591 Defaults to @samp{#f}.
12594 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12595 Binary to use for sending mails.
12596 Defaults to @samp{"/usr/sbin/sendmail"}.
12599 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12600 If non-empty, send mails via this SMTP host[:port] instead of
12602 Defaults to @samp{""}.
12605 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12606 Subject: header to use for rejection mails. You can use the same
12607 variables as for @samp{rejection-reason} below.
12608 Defaults to @samp{"Rejected: %s"}.
12611 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12612 Human readable error message for rejection mails. You can use
12625 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12628 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12629 Delimiter character between local-part and detail in email
12631 Defaults to @samp{"+"}.
12634 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12635 Header where the original recipient address (SMTP's RCPT TO:
12636 address) is taken from if not available elsewhere. With dovecot-lda -a
12637 parameter overrides this. A commonly used header for this is
12639 Defaults to @samp{""}.
12642 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12643 Should saving a mail to a nonexistent mailbox automatically create
12645 Defaults to @samp{#f}.
12648 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12649 Should automatically created mailboxes be also automatically
12651 Defaults to @samp{#f}.
12654 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12655 Maximum IMAP command line length. Some clients generate very long
12656 command lines with huge mailboxes, so you may need to raise this if you
12657 get "Too long argument" or "IMAP command line too large" errors
12659 Defaults to @samp{64000}.
12662 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12663 IMAP logout format string:
12666 total number of bytes read from client
12668 total number of bytes sent to client.
12670 Defaults to @samp{"in=%i out=%o"}.
12673 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12674 Override the IMAP CAPABILITY response. If the value begins with '+',
12675 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12676 Defaults to @samp{""}.
12679 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12680 How long to wait between "OK Still here" notifications when client
12682 Defaults to @samp{"2 mins"}.
12685 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12686 ID field names and values to send to clients. Using * as the value
12687 makes Dovecot use the default value. The following fields have default
12688 values currently: name, version, os, os-version, support-url,
12690 Defaults to @samp{""}.
12693 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12694 ID fields sent by client to log. * means everything.
12695 Defaults to @samp{""}.
12698 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12699 Workarounds for various client bugs:
12702 @item delay-newmail
12703 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12704 CHECK commands. Some clients ignore them otherwise, for example OSX
12705 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12706 may show user "Message no longer in server" errors. Note that OE6
12707 still breaks even with this workaround if synchronization is set to
12710 @item tb-extra-mailbox-sep
12711 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12712 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12713 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12715 @item tb-lsub-flags
12716 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12717 This makes Thunderbird realize they aren't selectable and show them
12718 greyed out, instead of only later giving "not selectable" popup error.
12720 Defaults to @samp{()}.
12723 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12724 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12725 Defaults to @samp{""}.
12729 Whew! Lots of configuration options. The nice thing about it though is
12730 that GuixSD has a complete interface to Dovecot's configuration
12731 language. This allows not only a nice way to declare configurations,
12732 but also offers reflective capabilities as well: users can write code to
12733 inspect and transform configurations from within Scheme.
12735 However, it could be that you just want to get a @code{dovecot.conf} up
12736 and running. In that case, you can pass an
12737 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12738 @code{dovecot-service}. As its name indicates, an opaque configuration
12739 does not have easy reflective capabilities.
12741 Available @code{opaque-dovecot-configuration} fields are:
12743 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12744 The dovecot package.
12747 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12748 The contents of the @code{dovecot.conf}, as a string.
12751 For example, if your @code{dovecot.conf} is just the empty string, you
12752 could instantiate a dovecot service like this:
12755 (dovecot-service #:config
12756 (opaque-dovecot-configuration
12760 @subsubheading OpenSMTPD Service
12762 @deffn {Scheme Variable} opensmtpd-service-type
12763 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12764 service, whose value should be an @code{opensmtpd-configuration} object
12765 as in this example:
12768 (service opensmtpd-service-type
12769 (opensmtpd-configuration
12770 (config-file (local-file "./my-smtpd.conf"))))
12774 @deftp {Data Type} opensmtpd-configuration
12775 Data type representing the configuration of opensmtpd.
12778 @item @code{package} (default: @var{opensmtpd})
12779 Package object of the OpenSMTPD SMTP server.
12781 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12782 File-like object of the OpenSMTPD configuration file to use. By default
12783 it listens on the loopback network interface, and allows for mail from
12784 users and daemons on the local machine, as well as permitting email to
12785 remote servers. Run @command{man smtpd.conf} for more information.
12790 @subsubheading Exim Service
12792 @cindex mail transfer agent (MTA)
12793 @cindex MTA (mail transfer agent)
12796 @deffn {Scheme Variable} exim-service-type
12797 This is the type of the @uref{https://exim.org, Exim} mail transfer
12798 agent (MTA), whose value should be an @code{exim-configuration} object
12799 as in this example:
12802 (service exim-service-type
12803 (exim-configuration
12804 (config-file (local-file "./my-exim.conf"))))
12808 In order to use an @code{exim-service-type} service you must also have a
12809 @code{mail-aliases-service-type} service present in your
12810 @code{operating-system} (even if it has no aliases).
12812 @deftp {Data Type} exim-configuration
12813 Data type representing the configuration of exim.
12816 @item @code{package} (default: @var{exim})
12817 Package object of the Exim server.
12819 @item @code{config-file} (default: @code{#f})
12820 File-like object of the Exim configuration file to use. If its value is
12821 @code{#f} then use the default configuration file from the package
12822 provided in @code{package}. The resulting configuration file is loaded
12823 after setting the @code{exim_user} and @code{exim_group} configuration
12829 @subsubheading Mail Aliases Service
12831 @cindex email aliases
12832 @cindex aliases, for email addresses
12834 @deffn {Scheme Variable} mail-aliases-service-type
12835 This is the type of the service which provides @code{/etc/aliases},
12836 specifying how to deliver mail to users on this system.
12839 (service mail-aliases-service-type
12840 '(("postmaster" "bob")
12841 ("bob" "bob@@example.com" "bob@@example2.com")))
12845 The configuration for a @code{mail-aliases-service-type} service is an
12846 association list denoting how to deliver mail that comes to this
12847 system. Each entry is of the form @code{(alias addresses ...)}, with
12848 @code{alias} specifying the local alias and @code{addresses} specifying
12849 where to deliver this user's mail.
12851 The aliases aren't required to exist as users on the local system. In
12852 the above example, there doesn't need to be a @code{postmaster} entry in
12853 the @code{operating-system}'s @code{user-accounts} in order to deliver
12854 the @code{postmaster} mail to @code{bob} (which subsequently would
12855 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
12857 @node Messaging Services
12858 @subsubsection Messaging Services
12863 The @code{(gnu services messaging)} module provides Guix service
12864 definitions for messaging services: currently only Prosody is supported.
12866 @subsubheading Prosody Service
12868 @deffn {Scheme Variable} prosody-service-type
12869 This is the type for the @uref{http://prosody.im, Prosody XMPP
12870 communication server}. Its value must be a @code{prosody-configuration}
12871 record as in this example:
12874 (service prosody-service-type
12875 (prosody-configuration
12876 (modules-enabled (cons "groups" %default-modules-enabled))
12879 (int-component-configuration
12880 (hostname "conference.example.net")
12882 (mod-muc (mod-muc-configuration)))))
12885 (virtualhost-configuration
12886 (domain "example.net"))))))
12889 See below for details about @code{prosody-configuration}.
12893 By default, Prosody does not need much configuration. Only one
12894 @code{virtualhosts} field is needed: it specifies the domain you wish
12897 Prosodyctl will help you generate X.509 certificates and keys:
12900 prosodyctl cert request example.net
12903 The available configuration parameters follow. Each parameter
12904 definition is preceded by its type; for example, @samp{string-list foo}
12905 indicates that the @code{foo} parameter should be specified as a list of
12906 strings. Types starting with @code{maybe-} denote parameters that won't
12907 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
12909 There is also a way to specify the configuration as a string, if you
12910 have an old @code{prosody.cfg.lua} file that you want to port over from
12911 some other system; see the end for more details.
12913 @c The following documentation was initially generated by
12914 @c (generate-documentation) in (gnu services messaging). Manually maintained
12915 @c documentation is better, so we shouldn't hesitate to edit below as
12916 @c needed. However if the change you want to make to this documentation
12917 @c can be done in an automated way, it's probably easier to change
12918 @c (generate-documentation) than to make it below and have to deal with
12919 @c the churn as Prosody updates.
12921 Available @code{prosody-configuration} fields are:
12923 @deftypevr {@code{prosody-configuration} parameter} package prosody
12924 The Prosody package.
12927 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
12928 Location of the Prosody data storage directory. See
12929 @url{http://prosody.im/doc/configure}.
12930 Defaults to @samp{"/var/lib/prosody"}.
12933 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
12934 Additional plugin directories. They are searched in all the specified
12935 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
12936 Defaults to @samp{()}.
12939 @deftypevr {@code{prosody-configuration} parameter} string-list admins
12940 This is a list of accounts that are admins for the server. Note that you
12941 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
12942 @url{http://prosody.im/doc/creating_accounts}.
12943 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
12944 Defaults to @samp{()}.
12947 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
12948 Enable use of libevent for better performance under high load. See
12949 @url{http://prosody.im/doc/libevent}.
12950 Defaults to @samp{#f}.
12953 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
12954 This is the list of modules Prosody will load on startup. It looks for
12955 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
12956 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
12957 Defaults to @samp{%default-modules-enabled}.
12960 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
12961 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
12962 should you want to disable them then add them to this list.
12963 Defaults to @samp{()}.
12966 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
12967 Path to a text file where the shared groups are defined. If this path is
12968 empty then @samp{mod_groups} does nothing. See
12969 @url{http://prosody.im/doc/modules/mod_groups}.
12970 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
12973 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
12974 Disable account creation by default, for security. See
12975 @url{http://prosody.im/doc/creating_accounts}.
12976 Defaults to @samp{#f}.
12979 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
12980 These are the SSL/TLS-related settings. Most of them are disabled so to
12981 use Prosody's defaults. If you do not completely understand these options, do
12982 not add them to your config, it is easy to lower the security of your server
12983 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
12985 Available @code{ssl-configuration} fields are:
12987 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
12988 This determines what handshake to use.
12991 @deftypevr {@code{ssl-configuration} parameter} file-name key
12992 Path to your private key file, relative to @code{/etc/prosody}.
12993 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
12996 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
12997 Path to your certificate file, relative to @code{/etc/prosody}.
12998 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13001 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13002 Path to directory containing root certificates that you wish Prosody to
13003 trust when verifying the certificates of remote servers.
13004 Defaults to @samp{"/etc/ssl/certs"}.
13007 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13008 Path to a file containing root certificates that you wish Prosody to trust.
13009 Similar to @code{capath} but with all certificates concatenated together.
13012 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13013 A list of verification options (these mostly map to OpenSSL's
13014 @code{set_verify()} flags).
13017 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13018 A list of general options relating to SSL/TLS. These map to OpenSSL's
13019 @code{set_options()}. For a full list of options available in LuaSec, see the
13023 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13024 How long a chain of certificate authorities to check when looking for a
13025 trusted root certificate.
13028 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13029 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13030 clients, and in what order.
13033 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13034 A path to a file containing parameters for Diffie-Hellman key exchange. You
13035 can create such a file with:
13036 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13039 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13040 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13041 @samp{"secp384r1"}.
13044 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13045 A list of "extra" verification options.
13048 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13049 Password for encrypted private keys.
13054 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13055 Whether to force all client-to-server connections to be encrypted or not.
13056 See @url{http://prosody.im/doc/modules/mod_tls}.
13057 Defaults to @samp{#f}.
13060 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13061 Whether to force all server-to-server connections to be encrypted or not.
13062 See @url{http://prosody.im/doc/modules/mod_tls}.
13063 Defaults to @samp{#f}.
13066 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13067 Whether to require encryption and certificate authentication. This
13068 provides ideal security, but requires servers you communicate with to support
13069 encryption AND present valid, trusted certificates. See
13070 @url{http://prosody.im/doc/s2s#security}.
13071 Defaults to @samp{#f}.
13074 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13075 Many servers don't support encryption or have invalid or self-signed
13076 certificates. You can list domains here that will not be required to
13077 authenticate using certificates. They will be authenticated using DNS. See
13078 @url{http://prosody.im/doc/s2s#security}.
13079 Defaults to @samp{()}.
13082 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13083 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13084 valid certificates for some domains by specifying a list here. See
13085 @url{http://prosody.im/doc/s2s#security}.
13086 Defaults to @samp{()}.
13089 @deftypevr {@code{prosody-configuration} parameter} string authentication
13090 Select the authentication backend to use. The default provider stores
13091 passwords in plaintext and uses Prosody's configured data storage to store the
13092 authentication data. If you do not trust your server please see
13093 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13094 about using the hashed backend. See also
13095 @url{http://prosody.im/doc/authentication}
13096 Defaults to @samp{"internal_plain"}.
13099 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13100 Set logging options. Advanced logging configuration is not yet supported
13101 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13102 Defaults to @samp{"*syslog"}.
13105 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13106 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13107 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13110 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13111 A host in Prosody is a domain on which user accounts can be created. For
13112 example if you want your users to have addresses like
13113 @samp{"john.smith@@example.com"} then you need to add a host
13114 @samp{"example.com"}. All options in this list will apply only to this host.
13116 Note: the name "virtual" host is used in configuration to avoid confusion with
13117 the actual physical host that Prosody is installed on. A single Prosody
13118 instance can serve many domains, each one defined as a VirtualHost entry in
13119 Prosody's configuration. Conversely a server that hosts a single domain would
13120 have just one VirtualHost entry.
13122 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13124 Available @code{virtualhost-configuration} fields are:
13126 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:
13127 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13128 Domain you wish Prosody to serve.
13133 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13134 Components are extra services on a server which are available to clients,
13135 usually on a subdomain of the main server (such as
13136 @samp{"mycomponent.example.com"}). Example components might be chatroom
13137 servers, user directories, or gateways to other protocols.
13139 Internal components are implemented with Prosody-specific plugins. To add an
13140 internal component, you simply fill the hostname field, and the plugin you wish
13141 to use for the component.
13143 See @url{http://prosody.im/doc/components}.
13144 Defaults to @samp{()}.
13146 Available @code{int-component-configuration} fields are:
13148 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:
13149 @deftypevr {@code{int-component-configuration} parameter} string hostname
13150 Hostname of the component.
13153 @deftypevr {@code{int-component-configuration} parameter} string plugin
13154 Plugin you wish to use for the component.
13157 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13158 Multi-user chat (MUC) is Prosody's module for allowing you to create
13159 hosted chatrooms/conferences for XMPP users.
13161 General information on setting up and using multi-user chatrooms can be found
13162 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13163 which you should read if you are new to XMPP chatrooms.
13165 See also @url{http://prosody.im/doc/modules/mod_muc}.
13167 Available @code{mod-muc-configuration} fields are:
13169 @deftypevr {@code{mod-muc-configuration} parameter} string name
13170 The name to return in service discovery responses.
13171 Defaults to @samp{"Prosody Chatrooms"}.
13174 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13175 If @samp{#t}, this will only allow admins to create new chatrooms.
13176 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13177 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13178 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13179 restricts to service administrators only.
13180 Defaults to @samp{#f}.
13183 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13184 Maximum number of history messages that will be sent to the member that has
13185 just joined the room.
13186 Defaults to @samp{20}.
13193 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13194 External components use XEP-0114, which most standalone components
13195 support. To add an external component, you simply fill the hostname field. See
13196 @url{http://prosody.im/doc/components}.
13197 Defaults to @samp{()}.
13199 Available @code{ext-component-configuration} fields are:
13201 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:
13202 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13203 Password which the component will use to log in.
13206 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13207 Hostname of the component.
13212 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13213 Port(s) Prosody listens on for component connections.
13216 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13217 Interface Prosody listens on for component connections.
13218 Defaults to @samp{"127.0.0.1"}.
13221 It could be that you just want to get a @code{prosody.cfg.lua}
13222 up and running. In that case, you can pass an
13223 @code{opaque-prosody-configuration} record as the value of
13224 @code{prosody-service-type}. As its name indicates, an opaque configuration
13225 does not have easy reflective capabilities.
13226 Available @code{opaque-prosody-configuration} fields are:
13228 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13229 The prosody package.
13232 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13233 The contents of the @code{prosody.cfg.lua} to use.
13236 For example, if your @code{prosody.cfg.lua} is just the empty
13237 string, you could instantiate a prosody service like this:
13240 (service prosody-service-type
13241 (opaque-prosody-configuration
13242 (prosody.cfg.lua "")))
13245 @node Kerberos Services
13246 @subsubsection Kerberos Services
13249 The @code{(gnu services kerberos)} module provides services relating to
13250 the authentication protocol @dfn{Kerberos}.
13252 @subsubheading Krb5 Service
13254 Programs using a Kerberos client library normally
13255 expect a configuration file in @file{/etc/krb5.conf}.
13256 This service generates such a file from a definition provided in the
13257 operating system declaration.
13258 It does not cause any daemon to be started.
13260 No ``keytab'' files are provided by this service---you must explicitly create them.
13261 This service is known to work with the MIT client library, @code{mit-krb5}.
13262 Other implementations have not been tested.
13264 @defvr {Scheme Variable} krb5-service-type
13265 A service type for Kerberos 5 clients.
13269 Here is an example of its use:
13271 (service krb5-service-type
13272 (krb5-configuration
13273 (default-realm "EXAMPLE.COM")
13274 (allow-weak-crypto? #t)
13277 (name "EXAMPLE.COM")
13278 (admin-server "groucho.example.com")
13279 (kdc "karl.example.com"))
13282 (admin-server "kerb-admin.argrx.edu")
13283 (kdc "keys.argrx.edu"))))))
13287 This example provides a Kerberos@tie{}5 client configuration which:
13289 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13290 of which have distinct administration servers and key distribution centers;
13291 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13292 specified by clients;
13293 @item Accepts services which only support encryption types known to be weak.
13296 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13297 Only the most commonly used ones are described here.
13298 For a full list, and more detailed explanation of each, see the MIT
13299 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13303 @deftp {Data Type} krb5-realm
13304 @cindex realm, kerberos
13307 This field is a string identifying the name of the realm.
13308 A common convention is to use the fully qualified DNS name of your organization,
13309 converted to upper case.
13311 @item @code{admin-server}
13312 This field is a string identifying the host where the administration server is
13316 This field is a string identifying the key distribution center
13321 @deftp {Data Type} krb5-configuration
13324 @item @code{allow-weak-crypto?} (default: @code{#f})
13325 If this flag is @code{#t} then services which only offer encryption algorithms
13326 known to be weak will be accepted.
13328 @item @code{default-realm} (default: @code{#f})
13329 This field should be a string identifying the default Kerberos
13330 realm for the client.
13331 You should set this field to the name of your Kerberos realm.
13332 If this value is @code{#f}
13333 then a realm must be specified with every Kerberos principal when invoking programs
13334 such as @command{kinit}.
13336 @item @code{realms}
13337 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13339 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13345 @subsubheading PAM krb5 Service
13348 The @code{pam-krb5} service allows for login authentication and password
13349 management via Kerberos.
13350 You will need this service if you want PAM enabled applications to authenticate
13351 users using Kerberos.
13353 @defvr {Scheme Variable} pam-krb5-service-type
13354 A service type for the Kerberos 5 PAM module.
13357 @deftp {Data Type} pam-krb5-configuration
13358 Data type representing the configuration of the Kerberos 5 PAM module
13359 This type has the following parameters:
13361 @item @code{pam-krb5} (default: @code{pam-krb5})
13362 The pam-krb5 package to use.
13364 @item @code{minimum-uid} (default: @code{1000})
13365 The smallest user ID for which Kerberos authentications should be attempted.
13366 Local accounts with lower values will silently fail to authenticate.
13372 @subsubsection Web Services
13377 The @code{(gnu services web)} module provides the following service:
13379 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13380 [#:log-directory ``/var/log/nginx''] @
13381 [#:run-directory ``/var/run/nginx''] @
13382 [#:server-list '()] @
13383 [#:upstream-list '()] @
13384 [#:config-file @code{#f}]
13386 Return a service that runs @var{nginx}, the nginx web server.
13388 The nginx daemon loads its runtime configuration from @var{config-file}.
13389 Log files are written to @var{log-directory} and temporary runtime data
13390 files are written to @var{run-directory}. For proper operation, these
13391 arguments should match what is in @var{config-file} to ensure that the
13392 directories are created when the service is activated.
13394 As an alternative to using a @var{config-file}, @var{server-list} can be
13395 used to specify the list of @dfn{server blocks} required on the host and
13396 @var{upstream-list} can be used to specify a list of @dfn{upstream
13397 blocks} to configure. For this to work, use the default value for
13400 At startup, @command{nginx} has not yet read its configuration file, so it
13401 uses a default file to log error messages. If it fails to load its
13402 configuration file, that is where error messages are logged. After the
13403 configuration file is loaded, the default error log file changes as per
13404 configuration. In our case, startup error messages can be found in
13405 @file{/var/run/nginx/logs/error.log}, and after configuration in
13406 @file{/var/log/nginx/error.log}. The second location can be changed with the
13407 @var{log-directory} configuration option.
13411 @deffn {Scheme Variable} nginx-service-type
13412 This is type for the nginx web server.
13414 This service can be extended to add server blocks in addition to the
13415 default one, as in this example:
13418 (simple-service 'my-extra-server nginx-service-type
13419 (list (nginx-server-configuration
13421 (root "/srv/http/extra-website"))))
13425 @deftp {Data Type} nginx-server-configuration
13426 Data type representing the configuration of an nginx server block.
13427 This type has the following parameters:
13430 @item @code{http-port} (default: @code{80})
13431 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13432 nginx should not listen for HTTP (non secure) connection for this
13433 @dfn{server block}.
13435 @item @code{https-port} (default: @code{443})
13436 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13437 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13439 Note that nginx can listen for HTTP and HTTPS connections in the same
13440 @dfn{server block}.
13442 @item @code{server-name} (default: @code{(list 'default)})
13443 A list of server names this server represents. @code{'default} represents the
13444 default server for connections matching no other server.
13446 @item @code{root} (default: @code{"/srv/http"})
13447 Root of the website nginx will serve.
13449 @item @code{locations} (default: @code{'()})
13450 A list of @dfn{nginx-location-configuration} or
13451 @dfn{nginx-named-location-configuration} records to use within this
13454 @item @code{index} (default: @code{(list "index.html")})
13455 Index files to look for when clients ask for a directory. If it cannot be found,
13456 Nginx will send the list of files in the directory.
13458 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13459 Where to find the certificate for secure connections. Set it to @code{#f} if
13460 you don't have a certificate or you don't want to use HTTPS.
13462 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13463 Where to find the private key for secure connections. Set it to @code{#f} if
13464 you don't have a key or you don't want to use HTTPS.
13466 @item @code{server-tokens?} (default: @code{#f})
13467 Whether the server should add its configuration to response.
13473 @subsubsection VPN Services
13474 @cindex VPN (virtual private network)
13475 @cindex virtual private network (VPN)
13477 The @code{(gnu services vpn)} module provides services related to
13478 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
13479 your machine to connect to a VPN, and a @emph{servire} service for your machine
13480 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
13482 @deffn {Scheme Procedure} openvpn-client-service @
13483 [#:config (openvpn-client-configuration)]
13485 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
13488 @deffn {Scheme Procedure} openvpn-server-service @
13489 [#:config (openvpn-server-configuration)]
13491 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
13493 Both can be run simultaneously.
13496 @c %automatically generated documentation
13498 Available @code{openvpn-client-configuration} fields are:
13500 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
13501 The OpenVPN package.
13505 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
13506 The OpenVPN pid file.
13508 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13512 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
13513 The protocol (UDP or TCP) used to open a channel between clients and
13516 Defaults to @samp{udp}.
13520 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
13521 The device type used to represent the VPN connection.
13523 Defaults to @samp{tun}.
13527 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
13528 The certificate authority to check connections against.
13530 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13534 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
13535 The certificate of the machine the daemon is running on. It should be
13536 signed by the authority given in @code{ca}.
13538 Defaults to @samp{"/etc/openvpn/client.crt"}.
13542 @deftypevr {@code{openvpn-client-configuration} parameter} string key
13543 The key of the machine the daemon is running on. It must be the key whose
13544 certificate is @code{cert}.
13546 Defaults to @samp{"/etc/openvpn/client.key"}.
13550 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
13551 Whether to use the lzo compression algorithm.
13553 Defaults to @samp{#t}.
13557 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
13558 Don't re-read key files across SIGUSR1 or --ping-restart.
13560 Defaults to @samp{#t}.
13564 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
13565 Don't close and reopen TUN/TAP device or run up/down scripts across
13566 SIGUSR1 or --ping-restart restarts.
13568 Defaults to @samp{#t}.
13572 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
13575 Defaults to @samp{3}.
13579 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
13580 Add an additional layer of HMAC authentication on top of the TLS control
13581 channel to protect against DoS attacks.
13583 Defaults to @samp{#f}.
13587 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
13588 Whether to check the server certificate has server usage extension.
13590 Defaults to @samp{#t}.
13594 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
13595 Bind to a specific local port number.
13597 Defaults to @samp{#f}.
13601 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
13602 Retry resolving server address.
13604 Defaults to @samp{#t}.
13608 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
13609 A list of remote servers to connect to.
13611 Defaults to @samp{()}.
13613 Available @code{openvpn-remote-configuration} fields are:
13615 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
13618 Defaults to @samp{"my-server"}.
13622 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
13623 Port number the server listens to.
13625 Defaults to @samp{1194}.
13630 @c %end of automatic openvpn-client documentation
13632 @c %automatically generated documentation
13634 Available @code{openvpn-server-configuration} fields are:
13636 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
13637 The OpenVPN package.
13641 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
13642 The OpenVPN pid file.
13644 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13648 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
13649 The protocol (UDP or TCP) used to open a channel between clients and
13652 Defaults to @samp{udp}.
13656 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
13657 The device type used to represent the VPN connection.
13659 Defaults to @samp{tun}.
13663 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
13664 The certificate authority to check connections against.
13666 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13670 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
13671 The certificate of the machine the daemon is running on. It should be
13672 signed by the authority given in @code{ca}.
13674 Defaults to @samp{"/etc/openvpn/client.crt"}.
13678 @deftypevr {@code{openvpn-server-configuration} parameter} string key
13679 The key of the machine the daemon is running on. It must be the key whose
13680 certificate is @code{cert}.
13682 Defaults to @samp{"/etc/openvpn/client.key"}.
13686 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
13687 Whether to use the lzo compression algorithm.
13689 Defaults to @samp{#t}.
13693 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
13694 Don't re-read key files across SIGUSR1 or --ping-restart.
13696 Defaults to @samp{#t}.
13700 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
13701 Don't close and reopen TUN/TAP device or run up/down scripts across
13702 SIGUSR1 or --ping-restart restarts.
13704 Defaults to @samp{#t}.
13708 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
13711 Defaults to @samp{3}.
13715 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
13716 Add an additional layer of HMAC authentication on top of the TLS control
13717 channel to protect against DoS attacks.
13719 Defaults to @samp{#f}.
13723 @deftypevr {@code{openvpn-server-configuration} parameter} number port
13724 Specifies the port number on which the server listens.
13726 Defaults to @samp{1194}.
13730 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
13731 An ip and mask specifying the subnet inside the virtual network.
13733 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
13737 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
13738 A CIDR notation specifying the IPv6 subnet inside the virtual network.
13740 Defaults to @samp{#f}.
13744 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
13745 The Diffie-Hellman parameters file.
13747 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
13751 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
13752 The file that records client IPs.
13754 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
13758 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
13759 When true, the server will act as a gateway for its clients.
13761 Defaults to @samp{#f}.
13765 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
13766 When true, clients are allowed to talk to each other inside the VPN.
13768 Defaults to @samp{#f}.
13772 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
13773 Causes ping-like messages to be sent back and forth over the link so
13774 that each side knows when the other side has gone down. @code{keepalive}
13775 requires a pair. The first element is the period of the ping sending,
13776 and the second element is the timeout before considering the other side
13781 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
13782 The maximum number of clients.
13784 Defaults to @samp{100}.
13788 @deftypevr {@code{openvpn-server-configuration} parameter} string status
13789 The status file. This file shows a small report on current connection.
13790 It is truncated and rewritten every minute.
13792 Defaults to @samp{"/var/run/openvpn/status"}.
13796 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
13797 The list of configuration for some clients.
13799 Defaults to @samp{()}.
13801 Available @code{openvpn-ccd-configuration} fields are:
13803 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
13806 Defaults to @samp{"client"}.
13810 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
13813 Defaults to @samp{#f}.
13817 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
13820 Defaults to @samp{#f}.
13827 @c %end of automatic openvpn-server documentation
13830 @deftp {Data Type} nginx-upstream-configuration
13831 Data type representing the configuration of an nginx @code{upstream}
13832 block. This type has the following parameters:
13836 Name for this group of servers.
13838 @item @code{servers}
13839 Specify the addresses of the servers in the group. The address can be
13840 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13841 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13842 prefix @samp{unix:}. For addresses using an IP address or domain name,
13843 the default port is 80, and a different port can be specified
13849 @deftp {Data Type} nginx-location-configuration
13850 Data type representing the configuration of an nginx @code{location}
13851 block. This type has the following parameters:
13855 URI which this location block matches.
13857 @anchor{nginx-location-configuration body}
13859 Body of the location block, specified as a string. This can contain many
13860 configuration directives. For example, to pass requests to a upstream
13861 server group defined using an @code{nginx-upstream-configuration} block,
13862 the following directive would be specified in the body @samp{proxy_pass
13863 http://upstream-name;}.
13868 @deftp {Data Type} nginx-named-location-configuration
13869 Data type representing the configuration of an nginx named location
13870 block. Named location blocks are used for request redirection, and not
13871 used for regular request processing. This type has the following
13876 Name to identify this location block.
13879 @xref{nginx-location-configuration body}, as the body for named location
13880 blocks can be used in a similar way to the
13881 @code{nginx-location-configuration body}. One restriction is that the
13882 body of a named location block cannot contain location blocks.
13887 @node Network File System
13888 @subsubsection Network File System
13891 The @code{(gnu services nfs)} module provides the following services,
13892 which are most commonly used in relation to mounting or exporting
13893 directory trees as @dfn{network file systems} (NFS).
13895 @subsubheading RPC Bind Service
13898 The RPC Bind service provides a facility to map program numbers into
13899 universal addresses.
13900 Many NFS related services use this facility. Hence it is automatically
13901 started when a dependent service starts.
13903 @defvr {Scheme Variable} rpcbind-service-type
13904 A service type for the RPC portmapper daemon.
13908 @deftp {Data Type} rpcbind-configuration
13909 Data type representing the configuration of the RPC Bind Service.
13910 This type has the following parameters:
13912 @item @code{rpcbind} (default: @code{rpcbind})
13913 The rpcbind package to use.
13915 @item @code{warm-start?} (default: @code{#t})
13916 If this parameter is @code{#t}, then the daemon will read a
13917 state file on startup thus reloading state information saved by a previous
13923 @subsubheading Pipefs Pseudo File System
13927 The pipefs file system is used to transfer NFS related data
13928 between the kernel and user space programs.
13930 @defvr {Scheme Variable} pipefs-service-type
13931 A service type for the pipefs pseudo file system.
13934 @deftp {Data Type} pipefs-configuration
13935 Data type representing the configuration of the pipefs pseudo file system service.
13936 This type has the following parameters:
13938 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13939 The directory to which the file system is to be attached.
13944 @subsubheading GSS Daemon Service
13947 @cindex global security system
13949 The @dfn{global security system} (GSS) daemon provides strong security for RPC
13951 Before exchanging RPC requests an RPC client must establish a security
13952 context. Typically this is done using the Kerberos command @command{kinit}
13953 or automatically at login time using PAM services (@pxref{Kerberos Services}).
13955 @defvr {Scheme Variable} gss-service-type
13956 A service type for the Global Security System (GSS) daemon.
13959 @deftp {Data Type} gss-configuration
13960 Data type representing the configuration of the GSS daemon service.
13961 This type has the following parameters:
13963 @item @code{nfs-utils} (default: @code{nfs-utils})
13964 The package in which the @command{rpc.gssd} command is to be found.
13966 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13967 The directory where the pipefs file system is mounted.
13973 @subsubheading IDMAP Daemon Service
13975 @cindex name mapper
13977 The idmap daemon service provides mapping between user IDs and user names.
13978 Typically it is required in order to access file systems mounted via NFSv4.
13980 @defvr {Scheme Variable} idmap-service-type
13981 A service type for the Identity Mapper (IDMAP) daemon.
13984 @deftp {Data Type} idmap-configuration
13985 Data type representing the configuration of the IDMAP daemon service.
13986 This type has the following parameters:
13988 @item @code{nfs-utils} (default: @code{nfs-utils})
13989 The package in which the @command{rpc.idmapd} command is to be found.
13991 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13992 The directory where the pipefs file system is mounted.
13994 @item @code{domain} (default: @code{#f})
13995 The local NFSv4 domain name.
13996 This must be a string or @code{#f}.
13997 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14002 @node Continuous Integration
14003 @subsubsection Continuous Integration
14005 @cindex continuous integration
14006 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14007 integration tool for Guix. It can be used both for development and for
14008 providing substitutes to others (@pxref{Substitutes}).
14010 The @code{(gnu services cuirass)} module provides the following service.
14012 @defvr {Scheme Procedure} cuirass-service-type
14013 The type of the Cuirass service. Its value must be a
14014 @code{cuirass-configuration} object, as described below.
14017 To add build jobs, you have to set the @code{specifications} field of
14018 the configuration. Here is an example of a service defining a build job
14019 based on a specification that can be found in Cuirass source tree. This
14020 service polls the Guix repository and builds a subset of the Guix
14021 packages, as prescribed in the @file{gnu-system.scm} example spec:
14024 (let ((spec #~((#:name . "guix")
14025 (#:url . "git://git.savannah.gnu.org/guix.git")
14026 (#:load-path . ".")
14028 ;; Here we must provide an absolute file name.
14029 ;; We take jobs from one of the examples provided
14031 (#:file . #$(file-append
14033 "/tests/gnu-system.scm"))
14035 (#:proc . hydra-jobs)
14036 (#:arguments (subset . "hello"))
14037 (#:branch . "master"))))
14038 (service cuirass-service-type
14039 (cuirass-configuration
14040 (specifications #~(list #$spec)))))
14043 While information related to build jobs is located directly in the
14044 specifications, global settings for the @command{cuirass} process are
14045 accessible in other @code{cuirass-configuration} fields.
14047 @deftp {Data Type} cuirass-configuration
14048 Data type representing the configuration of Cuirass.
14051 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14052 Location of the log file.
14054 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14055 Location of the repository cache.
14057 @item @code{user} (default: @code{"cuirass"})
14058 Owner of the @code{cuirass} process.
14060 @item @code{group} (default: @code{"cuirass"})
14061 Owner's group of the @code{cuirass} process.
14063 @item @code{interval} (default: @code{60})
14064 Number of seconds between the poll of the repositories followed by the
14067 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14068 Location of sqlite database which contains the build results and previously
14069 added specifications.
14071 @item @code{port} (default: @code{8080})
14072 Port number used by the HTTP server.
14074 @item @code{specifications} (default: @code{#~'()})
14075 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14076 where a specification is an association list
14077 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14078 keys are keywords (@code{#:keyword-example}) as shown in the example
14081 @item @code{use-substitutes?} (default: @code{#f})
14082 This allows using substitutes to avoid building every dependencies of a job
14085 @item @code{one-shot?} (default: @code{#f})
14086 Only evaluate specifications and build derivations once.
14088 @item @code{load-path} (default: @code{'()})
14089 This allows users to define their own packages and make them visible to
14090 cuirass as in @command{guix build} command.
14092 @item @code{cuirass} (default: @code{cuirass})
14093 The Cuirass package to use.
14097 @node Power management Services
14098 @subsubsection Power management Services
14100 @cindex power management with TLP
14101 The @code{(gnu services pm)} module provides a Guix service definition
14102 for the Linux power management tool TLP.
14104 TLP enables various powersaving modes in userspace and kernel.
14105 Contrary to @code{upower-service}, it is not a passive,
14106 monitoring tool, as it will apply custom settings each time a new power
14107 source is detected. More information can be found at
14108 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14110 @deffn {Scheme Variable} tlp-service-type
14111 The service type for the TLP tool. Its value should be a valid
14112 TLP configuration (see below). To use the default settings, simply
14115 (service tlp-service-type)
14119 By default TLP does not need much configuration but most TLP parameters
14120 can be tweaked using @code{tlp-configuration}.
14122 Each parameter definition is preceded by its type; for example,
14123 @samp{boolean foo} indicates that the @code{foo} parameter
14124 should be specified as a boolean. Types starting with
14125 @code{maybe-} denote parameters that won't show up in TLP config file
14126 when their value is @code{'disabled}.
14128 @c The following documentation was initially generated by
14129 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14130 @c documentation is better, so we shouldn't hesitate to edit below as
14131 @c needed. However if the change you want to make to this documentation
14132 @c can be done in an automated way, it's probably easier to change
14133 @c (generate-documentation) than to make it below and have to deal with
14134 @c the churn as TLP updates.
14136 Available @code{tlp-configuration} fields are:
14138 @deftypevr {@code{tlp-configuration} parameter} package tlp
14143 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14144 Set to true if you wish to enable TLP.
14146 Defaults to @samp{#t}.
14150 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14151 Default mode when no power supply can be detected. Alternatives are AC
14154 Defaults to @samp{"AC"}.
14158 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14159 Number of seconds Linux kernel has to wait after the disk goes idle,
14160 before syncing on AC.
14162 Defaults to @samp{0}.
14166 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14167 Same as @code{disk-idle-ac} but on BAT mode.
14169 Defaults to @samp{2}.
14173 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14174 Dirty pages flushing periodicity, expressed in seconds.
14176 Defaults to @samp{15}.
14180 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14181 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14183 Defaults to @samp{60}.
14187 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14188 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14189 alternatives are powersave and performance. With acpi-cpufreq driver,
14190 alternatives are ondemand, powersave, performance and conservative.
14192 Defaults to @samp{disabled}.
14196 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14197 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14199 Defaults to @samp{disabled}.
14203 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14204 Set the min available frequency for the scaling governor on AC.
14206 Defaults to @samp{disabled}.
14210 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14211 Set the max available frequency for the scaling governor on AC.
14213 Defaults to @samp{disabled}.
14217 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14218 Set the min available frequency for the scaling governor on BAT.
14220 Defaults to @samp{disabled}.
14224 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14225 Set the max available frequency for the scaling governor on BAT.
14227 Defaults to @samp{disabled}.
14231 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14232 Limit the min P-state to control the power dissipation of the CPU, in AC
14233 mode. Values are stated as a percentage of the available performance.
14235 Defaults to @samp{disabled}.
14239 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14240 Limit the max P-state to control the power dissipation of the CPU, in AC
14241 mode. Values are stated as a percentage of the available performance.
14243 Defaults to @samp{disabled}.
14247 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14248 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14250 Defaults to @samp{disabled}.
14254 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14255 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14257 Defaults to @samp{disabled}.
14261 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14262 Enable CPU turbo boost feature on AC mode.
14264 Defaults to @samp{disabled}.
14268 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14269 Same as @code{cpu-boost-on-ac?} on BAT mode.
14271 Defaults to @samp{disabled}.
14275 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14276 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14277 used under light load conditions.
14279 Defaults to @samp{#f}.
14283 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14284 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14286 Defaults to @samp{#t}.
14290 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14291 Enable Linux kernel NMI watchdog.
14293 Defaults to @samp{#f}.
14297 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14298 For Linux kernels with PHC patch applied, change CPU voltages. An
14299 example value would be @samp{"F:V F:V F:V F:V"}.
14301 Defaults to @samp{disabled}.
14305 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14306 Set CPU performance versus energy saving policy on AC. Alternatives are
14307 performance, normal, powersave.
14309 Defaults to @samp{"performance"}.
14313 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14314 Same as @code{energy-perf-policy-ac} but on BAT mode.
14316 Defaults to @samp{"powersave"}.
14320 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14325 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14326 Hard disk advanced power management level.
14330 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14331 Same as @code{disk-apm-bat} but on BAT mode.
14335 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14336 Hard disk spin down timeout. One value has to be specified for each
14337 declared hard disk.
14339 Defaults to @samp{disabled}.
14343 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14344 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14346 Defaults to @samp{disabled}.
14350 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14351 Select IO scheduler for disk devices. One value has to be specified for
14352 each declared hard disk. Example alternatives are cfq, deadline and
14355 Defaults to @samp{disabled}.
14359 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14360 SATA aggressive link power management (ALPM) level. Alternatives are
14361 min_power, medium_power, max_performance.
14363 Defaults to @samp{"max_performance"}.
14367 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14368 Same as @code{sata-linkpwr-ac} but on BAT mode.
14370 Defaults to @samp{"min_power"}.
14374 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14375 Exclude specified SATA host devices for link power management.
14377 Defaults to @samp{disabled}.
14381 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14382 Enable Runtime Power Management for AHCI controller and disks on AC
14385 Defaults to @samp{disabled}.
14389 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14390 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14392 Defaults to @samp{disabled}.
14396 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14397 Seconds of inactivity before disk is suspended.
14399 Defaults to @samp{15}.
14403 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14404 PCI Express Active State Power Management level. Alternatives are
14405 default, performance, powersave.
14407 Defaults to @samp{"performance"}.
14411 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14412 Same as @code{pcie-aspm-ac} but on BAT mode.
14414 Defaults to @samp{"powersave"}.
14418 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14419 Radeon graphics clock speed level. Alternatives are low, mid, high,
14422 Defaults to @samp{"high"}.
14426 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14427 Same as @code{radeon-power-ac} but on BAT mode.
14429 Defaults to @samp{"low"}.
14433 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14434 Radeon dynamic power management method (DPM). Alternatives are battery,
14437 Defaults to @samp{"performance"}.
14441 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14442 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14444 Defaults to @samp{"battery"}.
14448 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14449 Radeon DPM performance level. Alternatives are auto, low, high.
14451 Defaults to @samp{"auto"}.
14455 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14456 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14458 Defaults to @samp{"auto"}.
14462 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14463 Wifi power saving mode.
14465 Defaults to @samp{#f}.
14469 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14470 Same as @code{wifi-power-ac?} but on BAT mode.
14472 Defaults to @samp{#t}.
14476 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14477 Disable wake on LAN.
14479 Defaults to @samp{#t}.
14483 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14484 Timeout duration in seconds before activating audio power saving on
14485 Intel HDA and AC97 devices. A value of 0 disables power saving.
14487 Defaults to @samp{0}.
14491 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14492 Same as @code{sound-powersave-ac} but on BAT mode.
14494 Defaults to @samp{1}.
14498 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
14499 Disable controller in powersaving mode on Intel HDA devices.
14501 Defaults to @samp{#t}.
14505 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
14506 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
14507 powered on again by releasing (and reinserting) the eject lever or by
14508 pressing the disc eject button on newer models.
14510 Defaults to @samp{#f}.
14514 @deftypevr {@code{tlp-configuration} parameter} string bay-device
14515 Name of the optical drive device to power off.
14517 Defaults to @samp{"sr0"}.
14521 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
14522 Runtime Power Management for PCI(e) bus devices. Alternatives are on
14525 Defaults to @samp{"on"}.
14529 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
14530 Same as @code{runtime-pm-ac} but on BAT mode.
14532 Defaults to @samp{"auto"}.
14536 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
14537 Runtime Power Management for all PCI(e) bus devices, except blacklisted
14540 Defaults to @samp{#t}.
14544 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
14545 Exclude specified PCI(e) device addresses from Runtime Power Management.
14547 Defaults to @samp{disabled}.
14551 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
14552 Exclude PCI(e) devices assigned to the specified drivers from Runtime
14557 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
14558 Enable USB autosuspend feature.
14560 Defaults to @samp{#t}.
14564 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
14565 Exclude specified devices from USB autosuspend.
14567 Defaults to @samp{disabled}.
14571 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
14572 Exclude WWAN devices from USB autosuspend.
14574 Defaults to @samp{#t}.
14578 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
14579 Include specified devices into USB autosuspend, even if they are already
14580 excluded by the driver or via @code{usb-blacklist-wwan?}.
14582 Defaults to @samp{disabled}.
14586 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
14587 Enable USB autosuspend before shutdown.
14589 Defaults to @samp{disabled}.
14593 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
14594 Restore radio device state (bluetooth, wifi, wwan) from previous
14595 shutdown on system startup.
14597 Defaults to @samp{#f}.
14601 @node Miscellaneous Services
14602 @subsubsection Miscellaneous Services
14606 @subsubheading Lirc Service
14608 The @code{(gnu services lirc)} module provides the following service.
14610 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
14611 [#:device #f] [#:driver #f] [#:config-file #f] @
14612 [#:extra-options '()]
14613 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
14614 decodes infrared signals from remote controls.
14616 Optionally, @var{device}, @var{driver} and @var{config-file}
14617 (configuration file name) may be specified. See @command{lircd} manual
14620 Finally, @var{extra-options} is a list of additional command-line options
14621 passed to @command{lircd}.
14625 @subsubheading Spice Service
14627 The @code{(gnu services spice)} module provides the following service.
14629 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
14630 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
14631 that enables sharing the clipboard with a vm and setting the guest display
14632 resolution when the graphical console window resizes.
14635 @subsubsection Dictionary Services
14637 The @code{(gnu services dict)} module provides the following service:
14639 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
14640 Return a service that runs the @command{dicod} daemon, an implementation
14641 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
14643 The optional @var{config} argument specifies the configuration for
14644 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
14645 default it serves the GNU Collaborative International Dictonary of English.
14647 You can add @command{open localhost} to your @file{~/.dico} file to make
14648 @code{localhost} the default server for @command{dico} client
14649 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
14652 @deftp {Data Type} dicod-configuration
14653 Data type representing the configuration of dicod.
14656 @item @code{dico} (default: @var{dico})
14657 Package object of the GNU Dico dictionary server.
14659 @item @code{interfaces} (default: @var{'("localhost")})
14660 This is the list of IP addresses and ports and possibly socket file
14661 names to listen to (@pxref{Server Settings, @code{listen} directive,,
14662 dico, GNU Dico Manual}).
14664 @item @code{handlers} (default: @var{'()})
14665 List of @code{<dicod-handler>} objects denoting handlers (module instances).
14667 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
14668 List of @code{<dicod-database>} objects denoting dictionaries to be served.
14672 @deftp {Data Type} dicod-handler
14673 Data type representing a dictionary handler (module instance).
14677 Name of the handler (module instance).
14679 @item @code{module} (default: @var{#f})
14680 Name of the dicod module of the handler (instance). If it is @code{#f},
14681 the module has the same name as the handler.
14682 (@pxref{Modules,,, dico, GNU Dico Manual}).
14684 @item @code{options}
14685 List of strings or gexps representing the arguments for the module handler
14689 @deftp {Data Type} dicod-database
14690 Data type representing a dictionary database.
14694 Name of the database, will be used in DICT commands.
14696 @item @code{handler}
14697 Name of the dicod handler (module instance) used by this database
14698 (@pxref{Handlers,,, dico, GNU Dico Manual}).
14700 @item @code{complex?} (default: @var{#f})
14701 Whether the database configuration complex. The complex configuration
14702 will need a corresponding @code{<dicod-handler>} object, otherwise not.
14704 @item @code{options}
14705 List of strings or gexps representing the arguments for the database
14706 (@pxref{Databases,,, dico, GNU Dico Manual}).
14710 @defvr {Scheme Variable} %dicod-database:gcide
14711 A @code{<dicod-database>} object serving the GNU Collaborative International
14712 Dictionary of English using the @code{gcide} package.
14715 The following is an example @code{dicod-service} configuration.
14718 (dicod-service #:config
14719 (dicod-configuration
14720 (handlers (list (dicod-handler
14724 (list #~(string-append "dbdir=" #$wordnet))))))
14725 (databases (list (dicod-database
14728 (handler "wordnet")
14729 (options '("database=wn")))
14730 %dicod-database:gcide))))
14733 @subsubsection Version Control
14735 The @code{(gnu services version-control)} module provides the following services:
14737 @subsubheading Git daemon service
14739 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
14741 Return a service that runs @command{git daemon}, a simple TCP server to
14742 expose repositories over the Git protocol for anonymous access.
14744 The optional @var{config} argument should be a
14745 @code{<git-daemon-configuration>} object, by default it allows read-only
14746 access to exported@footnote{By creating the magic file
14747 "git-daemon-export-ok" in the repository directory.} repositories under
14752 @deftp {Data Type} git-daemon-configuration
14753 Data type representing the configuration for @code{git-daemon-service}.
14756 @item @code{package} (default: @var{git})
14757 Package object of the Git distributed version control system.
14759 @item @code{export-all?} (default: @var{#f})
14760 Whether to allow access for all Git repositories, even if they do not
14761 have the @file{git-daemon-export-ok} file.
14763 @item @code{base-path} (default: @file{/srv/git})
14764 Whether to remap all the path requests as relative to the given path.
14765 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
14766 then if you later try to pull @code{git://example.com/hello.git}, git
14767 daemon will interpret the path as @code{/srv/git/hello.git}.
14769 @item @code{user-path} (default: @var{#f})
14770 Whether to allow @code{~user} notation to be used in requests. When
14771 specified with empty string, requests to @code{git://host/~alice/foo} is
14772 taken as a request to access @code{foo} repository in the home directory
14773 of user @code{alice}. If @var{(user-path "path")} is specified, the
14774 same request is taken as a request to access @code{path/foo} repository
14775 in the home directory of user @code{alice}.
14777 @item @code{listen} (default: @var{'()})
14778 Whether to listen on specific IP addresses or hostnames, defaults to
14781 @item @code{port} (default: @var{#f})
14782 Whether to listen on an alternative port, which defaults to 9418.
14784 @item @code{whitelist} (default: @var{'()})
14785 If not empty, only allow access to this list of directories.
14787 @item @code{extra-options} (default: @var{'()})
14788 Extra options will be passed to @code{git daemon}, please run
14789 @command{man git-daemon} for more information.
14794 @node Setuid Programs
14795 @subsection Setuid Programs
14797 @cindex setuid programs
14798 Some programs need to run with ``root'' privileges, even when they are
14799 launched by unprivileged users. A notorious example is the
14800 @command{passwd} program, which users can run to change their
14801 password, and which needs to access the @file{/etc/passwd} and
14802 @file{/etc/shadow} files---something normally restricted to root, for
14803 obvious security reasons. To address that, these executables are
14804 @dfn{setuid-root}, meaning that they always run with root privileges
14805 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
14806 for more info about the setuid mechanism.)
14808 The store itself @emph{cannot} contain setuid programs: that would be a
14809 security issue since any user on the system can write derivations that
14810 populate the store (@pxref{The Store}). Thus, a different mechanism is
14811 used: instead of changing the setuid bit directly on files that are in
14812 the store, we let the system administrator @emph{declare} which programs
14813 should be setuid root.
14815 The @code{setuid-programs} field of an @code{operating-system}
14816 declaration contains a list of G-expressions denoting the names of
14817 programs to be setuid-root (@pxref{Using the Configuration System}).
14818 For instance, the @command{passwd} program, which is part of the Shadow
14819 package, can be designated by this G-expression (@pxref{G-Expressions}):
14822 #~(string-append #$shadow "/bin/passwd")
14825 A default set of setuid programs is defined by the
14826 @code{%setuid-programs} variable of the @code{(gnu system)} module.
14828 @defvr {Scheme Variable} %setuid-programs
14829 A list of G-expressions denoting common programs that are setuid-root.
14831 The list includes commands such as @command{passwd}, @command{ping},
14832 @command{su}, and @command{sudo}.
14835 Under the hood, the actual setuid programs are created in the
14836 @file{/run/setuid-programs} directory at system activation time. The
14837 files in this directory refer to the ``real'' binaries, which are in the
14840 @node X.509 Certificates
14841 @subsection X.509 Certificates
14843 @cindex HTTPS, certificates
14844 @cindex X.509 certificates
14846 Web servers available over HTTPS (that is, HTTP over the transport-layer
14847 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
14848 that the client can then use to @emph{authenticate} the server. To do
14849 that, clients verify that the server's certificate is signed by a
14850 so-called @dfn{certificate authority} (CA). But to verify the CA's
14851 signature, clients must have first acquired the CA's certificate.
14853 Web browsers such as GNU@tie{}IceCat include their own set of CA
14854 certificates, such that they are able to verify CA signatures
14857 However, most other programs that can talk HTTPS---@command{wget},
14858 @command{git}, @command{w3m}, etc.---need to be told where CA
14859 certificates can be found.
14861 @cindex @code{nss-certs}
14862 In GuixSD, this is done by adding a package that provides certificates
14863 to the @code{packages} field of the @code{operating-system} declaration
14864 (@pxref{operating-system Reference}). GuixSD includes one such package,
14865 @code{nss-certs}, which is a set of CA certificates provided as part of
14866 Mozilla's Network Security Services.
14868 Note that it is @emph{not} part of @var{%base-packages}, so you need to
14869 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
14870 most applications and libraries look for certificates by default, points
14871 to the certificates installed globally.
14873 Unprivileged users, including users of Guix on a foreign distro,
14874 can also install their own certificate package in
14875 their profile. A number of environment variables need to be defined so
14876 that applications and libraries know where to find them. Namely, the
14877 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
14878 variables. Some applications add their own environment variables; for
14879 instance, the Git version control system honors the certificate bundle
14880 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
14881 would typically run something like:
14884 $ guix package -i nss-certs
14885 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
14886 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14887 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
14890 @node Name Service Switch
14891 @subsection Name Service Switch
14893 @cindex name service switch
14895 The @code{(gnu system nss)} module provides bindings to the
14896 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
14897 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
14898 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
14899 extended with new ``name'' lookup methods for system databases, which
14900 includes host names, service names, user accounts, and more (@pxref{Name
14901 Service Switch, System Databases and Name Service Switch,, libc, The GNU
14902 C Library Reference Manual}).
14904 The NSS configuration specifies, for each system database, which lookup
14905 method is to be used, and how the various methods are chained
14906 together---for instance, under which circumstances NSS should try the
14907 next method in the list. The NSS configuration is given in the
14908 @code{name-service-switch} field of @code{operating-system} declarations
14909 (@pxref{operating-system Reference, @code{name-service-switch}}).
14912 @cindex .local, host name lookup
14913 As an example, the declaration below configures the NSS to use the
14914 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
14915 back-end}, which supports host name lookups over multicast DNS (mDNS)
14916 for host names ending in @code{.local}:
14919 (name-service-switch
14920 (hosts (list %files ;first, check /etc/hosts
14922 ;; If the above did not succeed, try
14923 ;; with 'mdns_minimal'.
14925 (name "mdns_minimal")
14927 ;; 'mdns_minimal' is authoritative for
14928 ;; '.local'. When it returns "not found",
14929 ;; no need to try the next methods.
14930 (reaction (lookup-specification
14931 (not-found => return))))
14933 ;; Then fall back to DNS.
14937 ;; Finally, try with the "full" 'mdns'.
14942 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
14943 contains this configuration, so you will not have to type it if all you
14944 want is to have @code{.local} host lookup working.
14946 Note that, in this case, in addition to setting the
14947 @code{name-service-switch} of the @code{operating-system} declaration,
14948 you also need to use @code{avahi-service} (@pxref{Networking Services,
14949 @code{avahi-service}}), or @var{%desktop-services}, which includes it
14950 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
14951 to the name service cache daemon (@pxref{Base Services,
14952 @code{nscd-service}}).
14954 For convenience, the following variables provide typical NSS
14957 @defvr {Scheme Variable} %default-nss
14958 This is the default name service switch configuration, a
14959 @code{name-service-switch} object.
14962 @defvr {Scheme Variable} %mdns-host-lookup-nss
14963 This is the name service switch configuration with support for host name
14964 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
14967 The reference for name service switch configuration is given below. It
14968 is a direct mapping of the configuration file format of the C library , so
14969 please refer to the C library manual for more information (@pxref{NSS
14970 Configuration File,,, libc, The GNU C Library Reference Manual}).
14971 Compared to the configuration file format of libc NSS, it has the advantage
14972 not only of adding this warm parenthetic feel that we like, but also
14973 static checks: you will know about syntax errors and typos as soon as you
14974 run @command{guix system}.
14976 @deftp {Data Type} name-service-switch
14978 This is the data type representation the configuration of libc's name
14979 service switch (NSS). Each field below represents one of the supported
14996 The system databases handled by the NSS. Each of these fields must be a
14997 list of @code{<name-service>} objects (see below).
15001 @deftp {Data Type} name-service
15003 This is the data type representing an actual name service and the
15004 associated lookup action.
15008 A string denoting the name service (@pxref{Services in the NSS
15009 configuration,,, libc, The GNU C Library Reference Manual}).
15011 Note that name services listed here must be visible to nscd. This is
15012 achieved by passing the @code{#:name-services} argument to
15013 @code{nscd-service} the list of packages providing the needed name
15014 services (@pxref{Base Services, @code{nscd-service}}).
15017 An action specified using the @code{lookup-specification} macro
15018 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15019 Reference Manual}). For example:
15022 (lookup-specification (unavailable => continue)
15023 (success => return))
15028 @node Initial RAM Disk
15029 @subsection Initial RAM Disk
15032 @cindex initial RAM disk
15033 For bootstrapping purposes, the Linux-Libre kernel is passed an
15034 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15035 root file system as well as an initialization script. The latter is
15036 responsible for mounting the real root file system, and for loading any
15037 kernel modules that may be needed to achieve that.
15039 The @code{initrd} field of an @code{operating-system} declaration allows
15040 you to specify which initrd you would like to use. The @code{(gnu
15041 system linux-initrd)} module provides three ways to build an initrd: the
15042 high-level @code{base-initrd} procedure and the low-level
15043 @code{raw-initrd} and @code{expression->initrd} procedures.
15045 The @code{base-initrd} procedure is intended to cover most common uses.
15046 For example, if you want to add a bunch of kernel modules to be loaded
15047 at boot time, you can define the @code{initrd} field of the operating
15048 system declaration like this:
15051 (initrd (lambda (file-systems . rest)
15052 ;; Create a standard initrd that has modules "foo.ko"
15053 ;; and "bar.ko", as well as their dependencies, in
15054 ;; addition to the modules available by default.
15055 (apply base-initrd file-systems
15056 #:extra-modules '("foo" "bar")
15060 The @code{base-initrd} procedure also handles common use cases that
15061 involves using the system as a QEMU guest, or as a ``live'' system with
15062 volatile root file system.
15064 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15065 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15066 such as trying to guess which kernel modules and packages should be included
15067 to the initrd. An example use of @code{raw-initrd} is when a user has
15068 a custom Linux kernel configuration and default kernel modules included by
15069 @code{base-initrd} are not available.
15071 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15072 honors several options passed on the Linux kernel command line
15073 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15074 @code{-append} option of QEMU), notably:
15077 @item --load=@var{boot}
15078 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15079 program, once it has mounted the root file system.
15081 GuixSD uses this option to yield control to a boot program that runs the
15082 service activation programs and then spawns the GNU@tie{}Shepherd, the
15083 initialization system.
15085 @item --root=@var{root}
15086 Mount @var{root} as the root file system. @var{root} can be a
15087 device name like @code{/dev/sda1}, a partition label, or a partition
15090 @item --system=@var{system}
15091 Have @file{/run/booted-system} and @file{/run/current-system} point to
15094 @item modprobe.blacklist=@var{modules}@dots{}
15095 @cindex module, black-listing
15096 @cindex black list, of kernel modules
15097 Instruct the initial RAM disk as well as the @command{modprobe} command
15098 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15099 must be a comma-separated list of module names---e.g.,
15100 @code{usbkbd,9pnet}.
15103 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15104 tries to load kernel modules and to mount the root file system. Our
15105 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15106 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15107 Manual}, for more information on Guile's REPL.
15111 Now that you know all the features that initial RAM disks produced by
15112 @code{base-initrd} and @code{raw-initrd} provide,
15113 here is how to use it and customize it further.
15116 @cindex initial RAM disk
15117 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15118 [#:linux-modules '()] [#:mapped-devices '()] @
15119 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15120 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15121 a list of file systems to be mounted by the initrd, possibly in addition to
15122 the root file system specified on the kernel command line via @code{--root}.
15123 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15124 @var{mapped-devices} is a list of device mappings to realize before
15125 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15126 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15127 include @code{e2fsck/static} or other packages needed by the initrd to check
15130 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15131 parameters. When @var{virtio?} is true, load additional modules so that the
15132 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15134 When @var{volatile-root?} is true, the root file system is writable but any changes
15138 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15139 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15140 [#:virtio? #t] [#:extra-modules '()]
15141 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15142 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15143 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15144 also behaves as in @code{raw-initrd}.
15146 When @var{virtio?} is true, load additional modules so that the
15147 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15149 The initrd is automatically populated with all the kernel modules necessary
15150 for @var{file-systems} and for the given options. However, additional kernel
15151 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15152 loaded at boot time in the order in which they appear.
15155 Needless to say, the initrds we produce and use embed a
15156 statically-linked Guile, and the initialization program is a Guile
15157 program. That gives a lot of flexibility. The
15158 @code{expression->initrd} procedure builds such an initrd, given the
15159 program to run in that initrd.
15161 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15162 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15163 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15164 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15165 upon booting. All the derivations referenced by @var{exp} are
15166 automatically copied to the initrd.
15169 @node GRUB Configuration
15170 @subsection GRUB Configuration
15173 @cindex boot loader
15175 The operating system uses GNU@tie{}GRUB as its boot loader
15176 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
15177 configured using a @code{grub-configuration} declaration. This data type
15178 is exported by the @code{(gnu system grub)} module and described below.
15180 @deftp {Data Type} grub-configuration
15181 The type of a GRUB configuration declaration.
15185 @item @code{device}
15186 This is a string denoting the boot device. It must be a device name
15187 understood by the @command{grub-install} command, such as
15188 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
15191 @item @code{menu-entries} (default: @code{()})
15192 A possibly empty list of @code{menu-entry} objects (see below), denoting
15193 entries to appear in the GRUB boot menu, in addition to the current
15194 system entry and the entry pointing to previous system generations.
15196 @item @code{default-entry} (default: @code{0})
15197 The index of the default boot menu entry. Index 0 is for the entry of the
15200 @item @code{timeout} (default: @code{5})
15201 The number of seconds to wait for keyboard input before booting. Set to
15202 0 to boot immediately, and to -1 to wait indefinitely.
15204 @item @code{theme} (default: @var{%default-theme})
15205 The @code{grub-theme} object describing the theme to use.
15207 @item @code{grub} (default: @code{grub})
15208 The GRUB package to use.
15215 Should you want to list additional boot menu entries @i{via} the
15216 @code{menu-entries} field above, you will need to create them with the
15217 @code{menu-entry} form. For example, imagine you want to be able to
15218 boot another distro (hard to imagine!), you can define a menu entry
15223 (label "The Other Distro")
15224 (linux "/boot/old/vmlinux-2.6.32")
15225 (linux-arguments '("root=/dev/sda2"))
15226 (initrd "/boot/old/initrd"))
15231 @deftp {Data Type} menu-entry
15232 The type of an entry in the GRUB boot menu.
15237 The label to show in the menu---e.g., @code{"GNU"}.
15240 The Linux kernel image to boot, for example:
15243 (file-append linux-libre "/bzImage")
15246 It is also possible to specify a device explicitly in the file path
15247 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
15248 GNU GRUB manual}), for example:
15251 "(hd0,msdos1)/boot/vmlinuz"
15254 If the device is specified explicitly as above, then the @code{device}
15255 field is ignored entirely.
15257 @item @code{linux-arguments} (default: @code{()})
15258 The list of extra Linux kernel command-line arguments---e.g.,
15259 @code{("console=ttyS0")}.
15261 @item @code{initrd}
15262 A G-Expression or string denoting the file name of the initial RAM disk
15263 to use (@pxref{G-Expressions}).
15265 @item @code{device} (default: @code{#f})
15266 The device where the kernel and initrd are to be found---i.e., the GRUB
15267 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15269 This may be a file system label (a string), a file system UUID (a
15270 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
15271 search the device containing the file specified by the @code{linux}
15272 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
15273 an OS device name such as @file{/dev/sda1}.
15275 @item @code{device-mount-point} (default: @code{"/"})
15276 The mount point of the above device on the system. You probably do not
15277 need to change the default value. GuixSD uses it to strip the prefix of
15278 store file names for systems where @file{/gnu} or @file{/gnu/store} is
15279 on a separate partition.
15284 @c FIXME: Write documentation once it's stable.
15285 Themes are created using the @code{grub-theme} form, which is not
15288 @defvr {Scheme Variable} %default-theme
15289 This is the default GRUB theme used by the operating system, with a
15290 fancy background image displaying the GNU and Guix logos.
15294 @node Invoking guix system
15295 @subsection Invoking @code{guix system}
15297 Once you have written an operating system declaration as seen in the
15298 previous section, it can be @dfn{instantiated} using the @command{guix
15299 system} command. The synopsis is:
15302 guix system @var{options}@dots{} @var{action} @var{file}
15305 @var{file} must be the name of a file containing an
15306 @code{operating-system} declaration. @var{action} specifies how the
15307 operating system is instantiated. Currently the following values are
15312 Build the operating system described in @var{file}, activate it, and
15313 switch to it@footnote{This action (and the related actions
15314 @code{switch-generation} and @code{roll-back}) are usable only on
15315 systems already running GuixSD.}.
15317 This effects all the configuration specified in @var{file}: user
15318 accounts, system services, global package list, setuid programs, etc.
15319 The command starts system services specified in @var{file} that are not
15320 currently running; if a service is currently running, it does not
15321 attempt to upgrade it since this would not be possible without stopping it
15324 This command creates a new generation whose number is one greater than
15325 the current generation (as reported by @command{guix system
15326 list-generations}). If that generation already exists, it will be
15327 overwritten. This behavior mirrors that of @command{guix package}
15328 (@pxref{Invoking guix package}).
15330 It also adds a GRUB menu entry for the new OS configuration, and moves
15331 entries for older configurations to a submenu---unless
15332 @option{--no-bootloader} is passed.
15335 @c The paragraph below refers to the problem discussed at
15336 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15337 It is highly recommended to run @command{guix pull} once before you run
15338 @command{guix system reconfigure} for the first time (@pxref{Invoking
15339 guix pull}). Failing to do that you would see an older version of Guix
15340 once @command{reconfigure} has completed.
15343 @item switch-generation
15344 @cindex generations
15345 Switch to an existing system generation. This action atomically
15346 switches the system profile to the specified system generation. It also
15347 rearranges the system's existing GRUB menu entries. It makes the menu
15348 entry for the specified system generation the default, and it moves the
15349 entries for the other generations to a submenu. The next time the
15350 system boots, it will use the specified system generation.
15352 The target generation can be specified explicitly by its generation
15353 number. For example, the following invocation would switch to system
15357 guix system switch-generation 7
15360 The target generation can also be specified relative to the current
15361 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15362 ``3 generations ahead of the current generation,'' and @code{-1} means
15363 ``1 generation prior to the current generation.'' When specifying a
15364 negative value such as @code{-1}, you must precede it with @code{--} to
15365 prevent it from being parsed as an option. For example:
15368 guix system switch-generation -- -1
15371 Currently, the effect of invoking this action is @emph{only} to switch
15372 the system profile to an existing generation and rearrange the GRUB menu
15373 entries. To actually start using the target system generation, you must
15374 reboot after running this action. In the future, it will be updated to
15375 do the same things as @command{reconfigure}, like activating and
15376 deactivating services.
15378 This action will fail if the specified generation does not exist.
15381 @cindex rolling back
15382 Switch to the preceding system generation. The next time the system
15383 boots, it will use the preceding system generation. This is the inverse
15384 of @command{reconfigure}, and it is exactly the same as invoking
15385 @command{switch-generation} with an argument of @code{-1}.
15387 Currently, as with @command{switch-generation}, you must reboot after
15388 running this action to actually start using the preceding system
15392 Build the derivation of the operating system, which includes all the
15393 configuration files and programs needed to boot and run the system.
15394 This action does not actually install anything.
15397 Populate the given directory with all the files necessary to run the
15398 operating system specified in @var{file}. This is useful for first-time
15399 installations of GuixSD. For instance:
15402 guix system init my-os-config.scm /mnt
15405 copies to @file{/mnt} all the store items required by the configuration
15406 specified in @file{my-os-config.scm}. This includes configuration
15407 files, packages, and so on. It also creates other essential files
15408 needed for the system to operate correctly---e.g., the @file{/etc},
15409 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
15411 This command also installs GRUB on the device specified in
15412 @file{my-os-config}, unless the @option{--no-bootloader} option was passed.
15415 @cindex virtual machine
15417 @anchor{guix system vm}
15418 Build a virtual machine that contains the operating system declared in
15419 @var{file}, and return a script to run that virtual machine (VM).
15420 Arguments given to the script are passed to QEMU.
15422 The VM shares its store with the host system.
15424 Additional file systems can be shared between the host and the VM using
15425 the @code{--share} and @code{--expose} command-line options: the former
15426 specifies a directory to be shared with write access, while the latter
15427 provides read-only access to the shared directory.
15429 The example below creates a VM in which the user's home directory is
15430 accessible read-only, and where the @file{/exchange} directory is a
15431 read-write mapping of @file{$HOME/tmp} on the host:
15434 guix system vm my-config.scm \
15435 --expose=$HOME --share=$HOME/tmp=/exchange
15438 On GNU/Linux, the default is to boot directly to the kernel; this has
15439 the advantage of requiring only a very tiny root disk image since the
15440 store of the host can then be mounted.
15442 The @code{--full-boot} option forces a complete boot sequence, starting
15443 with the bootloader. This requires more disk space since a root image
15444 containing at least the kernel, initrd, and bootloader data files must
15445 be created. The @code{--image-size} option can be used to specify the
15450 Return a virtual machine or disk image of the operating system declared
15451 in @var{file} that stands alone. Use the @option{--image-size} option
15452 to specify the size of the image.
15454 When using @code{vm-image}, the returned image is in qcow2 format, which
15455 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
15456 for more information on how to run the image in a virtual machine.
15458 When using @code{disk-image}, a raw disk image is produced; it can be
15459 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
15460 the device corresponding to a USB stick, one can copy the image to it
15461 using the following command:
15464 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
15468 Return a script to run the operating system declared in @var{file}
15469 within a container. Containers are a set of lightweight isolation
15470 mechanisms provided by the kernel Linux-libre. Containers are
15471 substantially less resource-demanding than full virtual machines since
15472 the kernel, shared objects, and other resources can be shared with the
15473 host system; this also means they provide thinner isolation.
15475 Currently, the script must be run as root in order to support more than
15476 a single user and group. The container shares its store with the host
15479 As with the @code{vm} action (@pxref{guix system vm}), additional file
15480 systems to be shared between the host and container can be specified
15481 using the @option{--share} and @option{--expose} options:
15484 guix system container my-config.scm \
15485 --expose=$HOME --share=$HOME/tmp=/exchange
15489 This option requires Linux-libre 3.19 or newer.
15494 @var{options} can contain any of the common build options (@pxref{Common
15495 Build Options}). In addition, @var{options} can contain one of the
15499 @item --system=@var{system}
15500 @itemx -s @var{system}
15501 Attempt to build for @var{system} instead of the host system type.
15502 This works as per @command{guix build} (@pxref{Invoking guix build}).
15506 Return the derivation file name of the given operating system without
15509 @item --image-size=@var{size}
15510 For the @code{vm-image} and @code{disk-image} actions, create an image
15511 of the given @var{size}. @var{size} may be a number of bytes, or it may
15512 include a unit as a suffix (@pxref{Block size, size specifications,,
15513 coreutils, GNU Coreutils}).
15515 @item --root=@var{file}
15516 @itemx -r @var{file}
15517 Make @var{file} a symlink to the result, and register it as a garbage
15520 @item --on-error=@var{strategy}
15521 Apply @var{strategy} when an error occurs when reading @var{file}.
15522 @var{strategy} may be one of the following:
15525 @item nothing-special
15526 Report the error concisely and exit. This is the default strategy.
15529 Likewise, but also display a backtrace.
15532 Report the error and enter Guile's debugger. From there, you can run
15533 commands such as @code{,bt} to get a backtrace, @code{,locals} to
15534 display local variable values, and more generally inspect the state of the
15535 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
15536 a list of available debugging commands.
15541 All the actions above, except @code{build} and @code{init},
15542 can use KVM support in the Linux-libre kernel. Specifically, if the
15543 machine has hardware virtualization support, the corresponding
15544 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
15545 must exist and be readable and writable by the user and by the
15546 build users of the daemon (@pxref{Build Environment Setup}).
15549 Once you have built, configured, re-configured, and re-re-configured
15550 your GuixSD installation, you may find it useful to list the operating
15551 system generations available on disk---and that you can choose from the
15556 @item list-generations
15557 List a summary of each generation of the operating system available on
15558 disk, in a human-readable way. This is similar to the
15559 @option{--list-generations} option of @command{guix package}
15560 (@pxref{Invoking guix package}).
15562 Optionally, one can specify a pattern, with the same syntax that is used
15563 in @command{guix package --list-generations}, to restrict the list of
15564 generations displayed. For instance, the following command displays
15565 generations that are up to 10 days old:
15568 $ guix system list-generations 10d
15573 The @command{guix system} command has even more to offer! The following
15574 sub-commands allow you to visualize how your system services relate to
15577 @anchor{system-extension-graph}
15580 @item extension-graph
15581 Emit in Dot/Graphviz format to standard output the @dfn{service
15582 extension graph} of the operating system defined in @var{file}
15583 (@pxref{Service Composition}, for more information on service
15589 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
15592 produces a PDF file showing the extension relations among services.
15594 @anchor{system-shepherd-graph}
15595 @item shepherd-graph
15596 Emit in Dot/Graphviz format to standard output the @dfn{dependency
15597 graph} of shepherd services of the operating system defined in
15598 @var{file}. @xref{Shepherd Services}, for more information and for an
15603 @node Running GuixSD in a VM
15604 @subsection Running GuixSD in a Virtual Machine
15606 @cindex virtual machine
15607 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
15608 virtual machine image using @command{guix system vm-image}
15609 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
15610 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
15613 To run the image in QEMU, copy it out of the store (@pxref{The Store})
15614 and give yourself permission to write to the copy. When invoking QEMU,
15615 you must choose a system emulator that is suitable for your hardware
15616 platform. Here is a minimal QEMU invocation that will boot the result
15617 of @command{guix system vm-image} on x86_64 hardware:
15620 $ qemu-system-x86_64 \
15621 -net user -net nic,model=virtio \
15622 -enable-kvm -m 256 /tmp/qemu-image
15625 Here is what each of these options means:
15628 @item qemu-system-x86_64
15629 This specifies the hardware platform to emulate. This should match the
15633 Enable the unprivileged user-mode network stack. The guest OS can
15634 access the host but not vice versa. This is the simplest way to get the
15637 @item -net nic,model=virtio
15638 You must create a network interface of a given model. If you do not
15639 create a NIC, the boot will fail. Assuming your hardware platform is
15640 x86_64, you can get a list of available NIC models by running
15641 @command{qemu-system-x86_64 -net nic,model=help}.
15644 If your system has hardware virtualization extensions, enabling the
15645 virtual machine support (KVM) of the Linux kernel will make things run
15649 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
15650 which may be insufficient for some operations.
15652 @item /tmp/qemu-image
15653 The file name of the qcow2 image.
15656 The default @command{run-vm.sh} script that is returned by an invocation of
15657 @command{guix system vm} does not add a @command{-net user} flag by default.
15658 To get network access from within the vm add the @code{(dhcp-client-service)}
15659 to your system definition and start the VM using
15660 @command{`guix system vm config.scm` -net user}. An important caveat of using
15661 @command{-net user} for networking is that @command{ping} will not work, because
15662 it uses the ICMP protocol. You'll have to use a different command to check for
15663 network connectivity, like for example @command{curl}.
15665 @subsubsection Connecting Through SSH
15669 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
15670 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
15671 boot unsupervised. It requires you to type some characters to initialize the
15672 randomness generator. In addition you need to forward the SSH port, 22 by
15673 default, to the host. You can do this with
15676 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
15679 To connect to the VM you can run
15682 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
15685 The @command{-p} tells @command{ssh} the port you want to connect to.
15686 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
15687 every time you modify your @command{config.scm} file and the
15688 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
15689 connection to an unknown host every time you connect.
15691 @subsubsection Using @command{virt-viewer} with Spice
15693 As an alternative to the default @command{qemu} graphical client you can
15694 use the @command{remote-viewer} from the @command{virt-viewer} package. To
15695 connect pass the @command{-spice port=5930,disable-ticketing} flag to
15696 @command{qemu}. See previous section for further information on how to do this.
15698 Spice also allows you to do some nice stuff like share your clipboard with your
15699 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
15702 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
15703 -chardev spicevmc,name=vdagent,id=vdagent
15704 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
15705 name=com.redhat.spice.0
15708 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
15710 @node Defining Services
15711 @subsection Defining Services
15713 The previous sections show the available services and how one can combine
15714 them in an @code{operating-system} declaration. But how do we define
15715 them in the first place? And what is a service anyway?
15718 * Service Composition:: The model for composing services.
15719 * Service Types and Services:: Types and services.
15720 * Service Reference:: API reference.
15721 * Shepherd Services:: A particular type of service.
15724 @node Service Composition
15725 @subsubsection Service Composition
15729 Here we define a @dfn{service} as, broadly, something that extends the
15730 functionality of the operating system. Often a service is a process---a
15731 @dfn{daemon}---started when the system boots: a secure shell server, a
15732 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
15733 whose execution can be triggered by another daemon---e.g., an FTP server
15734 started by @command{inetd} or a D-Bus service activated by
15735 @command{dbus-daemon}. Occasionally, a service does not map to a
15736 daemon. For instance, the ``account'' service collects user accounts
15737 and makes sure they exist when the system runs; the ``udev'' service
15738 collects device management rules and makes them available to the eudev
15739 daemon; the @file{/etc} service populates the @file{/etc} directory
15742 @cindex service extensions
15743 GuixSD services are connected by @dfn{extensions}. For instance, the
15744 secure shell service @emph{extends} the Shepherd---the GuixSD
15745 initialization system, running as PID@tie{}1---by giving it the command
15746 lines to start and stop the secure shell daemon (@pxref{Networking
15747 Services, @code{lsh-service}}); the UPower service extends the D-Bus
15748 service by passing it its @file{.service} specification, and extends the
15749 udev service by passing it device management rules (@pxref{Desktop
15750 Services, @code{upower-service}}); the Guix daemon service extends the
15751 Shepherd by passing it the command lines to start and stop the daemon,
15752 and extends the account service by passing it a list of required build
15753 user accounts (@pxref{Base Services}).
15755 All in all, services and their ``extends'' relations form a directed
15756 acyclic graph (DAG). If we represent services as boxes and extensions
15757 as arrows, a typical system might provide something like this:
15759 @image{images/service-graph,,5in,Typical service extension graph.}
15761 @cindex system service
15762 At the bottom, we see the @dfn{system service}, which produces the
15763 directory containing everything to run and boot the system, as returned
15764 by the @command{guix system build} command. @xref{Service Reference},
15765 to learn about the other service types shown here.
15766 @xref{system-extension-graph, the @command{guix system extension-graph}
15767 command}, for information on how to generate this representation for a
15768 particular operating system definition.
15770 @cindex service types
15771 Technically, developers can define @dfn{service types} to express these
15772 relations. There can be any number of services of a given type on the
15773 system---for instance, a system running two instances of the GNU secure
15774 shell server (lsh) has two instances of @var{lsh-service-type}, with
15775 different parameters.
15777 The following section describes the programming interface for service
15778 types and services.
15780 @node Service Types and Services
15781 @subsubsection Service Types and Services
15783 A @dfn{service type} is a node in the DAG described above. Let us start
15784 with a simple example, the service type for the Guix build daemon
15785 (@pxref{Invoking guix-daemon}):
15788 (define guix-service-type
15792 (list (service-extension shepherd-root-service-type guix-shepherd-service)
15793 (service-extension account-service-type guix-accounts)
15794 (service-extension activation-service-type guix-activation)))
15795 (default-value (guix-configuration))))
15799 It defines three things:
15803 A name, whose sole purpose is to make inspection and debugging easier.
15806 A list of @dfn{service extensions}, where each extension designates the
15807 target service type and a procedure that, given the parameters of the
15808 service, returns a list of objects to extend the service of that type.
15810 Every service type has at least one service extension. The only
15811 exception is the @dfn{boot service type}, which is the ultimate service.
15814 Optionally, a default value for instances of this type.
15817 In this example, @var{guix-service-type} extends three services:
15820 @item shepherd-root-service-type
15821 The @var{guix-shepherd-service} procedure defines how the Shepherd
15822 service is extended. Namely, it returns a @code{<shepherd-service>}
15823 object that defines how @command{guix-daemon} is started and stopped
15824 (@pxref{Shepherd Services}).
15826 @item account-service-type
15827 This extension for this service is computed by @var{guix-accounts},
15828 which returns a list of @code{user-group} and @code{user-account}
15829 objects representing the build user accounts (@pxref{Invoking
15832 @item activation-service-type
15833 Here @var{guix-activation} is a procedure that returns a gexp, which is
15834 a code snippet to run at ``activation time''---e.g., when the service is
15838 A service of this type is instantiated like this:
15841 (service guix-service-type
15842 (guix-configuration
15844 (use-substitutes? #f)))
15847 The second argument to the @code{service} form is a value representing
15848 the parameters of this specific service instance.
15849 @xref{guix-configuration-type, @code{guix-configuration}}, for
15850 information about the @code{guix-configuration} data type. When the
15851 value is omitted, the default value specified by
15852 @code{guix-service-type} is used:
15855 (service guix-service-type)
15858 @var{guix-service-type} is quite simple because it extends other
15859 services but is not extensible itself.
15861 @c @subsubsubsection Extensible Service Types
15863 The service type for an @emph{extensible} service looks like this:
15866 (define udev-service-type
15867 (service-type (name 'udev)
15869 (list (service-extension shepherd-root-service-type
15870 udev-shepherd-service)))
15872 (compose concatenate) ;concatenate the list of rules
15873 (extend (lambda (config rules)
15875 (($ <udev-configuration> udev initial-rules)
15876 (udev-configuration
15877 (udev udev) ;the udev package to use
15878 (rules (append initial-rules rules)))))))))
15881 This is the service type for the
15882 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
15883 management daemon}. Compared to the previous example, in addition to an
15884 extension of @var{shepherd-root-service-type}, we see two new fields:
15888 This is the procedure to @dfn{compose} the list of extensions to
15889 services of this type.
15891 Services can extend the udev service by passing it lists of rules; we
15892 compose those extensions simply by concatenating them.
15895 This procedure defines how the value of the service is @dfn{extended} with
15896 the composition of the extensions.
15898 Udev extensions are composed into a list of rules, but the udev service
15899 value is itself a @code{<udev-configuration>} record. So here, we
15900 extend that record by appending the list of rules it contains to the
15901 list of contributed rules.
15904 There can be only one instance of an extensible service type such as
15905 @var{udev-service-type}. If there were more, the
15906 @code{service-extension} specifications would be ambiguous.
15908 Still here? The next section provides a reference of the programming
15909 interface for services.
15911 @node Service Reference
15912 @subsubsection Service Reference
15914 We have seen an overview of service types (@pxref{Service Types and
15915 Services}). This section provides a reference on how to manipulate
15916 services and service types. This interface is provided by the
15917 @code{(gnu services)} module.
15919 @deffn {Scheme Procedure} service @var{type} [@var{value}]
15920 Return a new service of @var{type}, a @code{<service-type>} object (see
15921 below.) @var{value} can be any object; it represents the parameters of
15922 this particular service instance.
15924 When @var{value} is omitted, the default value specified by @var{type}
15925 is used; if @var{type} does not specify a default value, an error is
15928 For instance, this:
15931 (service openssh-service-type)
15935 is equivalent to this:
15938 (service openssh-service-type
15939 (openssh-configuration))
15942 In both cases the result is an instance of @code{openssh-service-type}
15943 with the default configuration.
15946 @deffn {Scheme Procedure} service? @var{obj}
15947 Return true if @var{obj} is a service.
15950 @deffn {Scheme Procedure} service-kind @var{service}
15951 Return the type of @var{service}---i.e., a @code{<service-type>} object.
15954 @deffn {Scheme Procedure} service-value @var{service}
15955 Return the value associated with @var{service}. It represents its
15959 Here is an example of how a service is created and manipulated:
15963 (service nginx-service-type
15964 (nginx-configuration
15966 (log-directory log-directory)
15967 (run-directory run-directory)
15968 (file config-file))))
15973 (eq? (service-kind s) nginx-service-type)
15977 The @code{modify-services} form provides a handy way to change the
15978 parameters of some of the services of a list such as
15979 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
15980 evaluates to a list of services. Of course, you could always use
15981 standard list combinators such as @code{map} and @code{fold} to do that
15982 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
15983 @code{modify-services} simply provides a more concise form for this
15986 @deffn {Scheme Syntax} modify-services @var{services} @
15987 (@var{type} @var{variable} => @var{body}) @dots{}
15989 Modify the services listed in @var{services} according to the given
15990 clauses. Each clause has the form:
15993 (@var{type} @var{variable} => @var{body})
15996 where @var{type} is a service type---e.g.,
15997 @code{guix-service-type}---and @var{variable} is an identifier that is
15998 bound within the @var{body} to the service parameters---e.g., a
15999 @code{guix-configuration} instance---of the original service of that
16002 The @var{body} should evaluate to the new service parameters, which will
16003 be used to configure the new service. This new service will replace the
16004 original in the resulting list. Because a service's service parameters
16005 are created using @code{define-record-type*}, you can write a succinct
16006 @var{body} that evaluates to the new service parameters by using the
16007 @code{inherit} feature that @code{define-record-type*} provides.
16009 @xref{Using the Configuration System}, for example usage.
16013 Next comes the programming interface for service types. This is
16014 something you want to know when writing new service definitions, but not
16015 necessarily when simply looking for ways to customize your
16016 @code{operating-system} declaration.
16018 @deftp {Data Type} service-type
16019 @cindex service type
16020 This is the representation of a @dfn{service type} (@pxref{Service Types
16025 This is a symbol, used only to simplify inspection and debugging.
16027 @item @code{extensions}
16028 A non-empty list of @code{<service-extension>} objects (see below).
16030 @item @code{compose} (default: @code{#f})
16031 If this is @code{#f}, then the service type denotes services that cannot
16032 be extended---i.e., services that do not receive ``values'' from other
16035 Otherwise, it must be a one-argument procedure. The procedure is called
16036 by @code{fold-services} and is passed a list of values collected from
16037 extensions. It must return a value that is a valid parameter value for
16038 the service instance.
16040 @item @code{extend} (default: @code{#f})
16041 If this is @code{#f}, services of this type cannot be extended.
16043 Otherwise, it must be a two-argument procedure: @code{fold-services}
16044 calls it, passing it the initial value of the service as the first argument
16045 and the result of applying @code{compose} to the extension values as the
16049 @xref{Service Types and Services}, for examples.
16052 @deffn {Scheme Procedure} service-extension @var{target-type} @
16054 Return a new extension for services of type @var{target-type}.
16055 @var{compute} must be a one-argument procedure: @code{fold-services}
16056 calls it, passing it the value associated with the service that provides
16057 the extension; it must return a valid value for the target service.
16060 @deffn {Scheme Procedure} service-extension? @var{obj}
16061 Return true if @var{obj} is a service extension.
16064 Occasionally, you might want to simply extend an existing service. This
16065 involves creating a new service type and specifying the extension of
16066 interest, which can be verbose; the @code{simple-service} procedure
16067 provides a shorthand for this.
16069 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16070 Return a service that extends @var{target} with @var{value}. This works
16071 by creating a singleton service type @var{name}, of which the returned
16072 service is an instance.
16074 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16078 (simple-service 'my-mcron-job mcron-service-type
16079 #~(job '(next-hour (3)) "guix gc -F 2G"))
16083 At the core of the service abstraction lies the @code{fold-services}
16084 procedure, which is responsible for ``compiling'' a list of services
16085 down to a single directory that contains everything needed to boot and
16086 run the system---the directory shown by the @command{guix system build}
16087 command (@pxref{Invoking guix system}). In essence, it propagates
16088 service extensions down the service graph, updating each node parameters
16089 on the way, until it reaches the root node.
16091 @deffn {Scheme Procedure} fold-services @var{services} @
16092 [#:target-type @var{system-service-type}]
16093 Fold @var{services} by propagating their extensions down to the root of
16094 type @var{target-type}; return the root service adjusted accordingly.
16097 Lastly, the @code{(gnu services)} module also defines several essential
16098 service types, some of which are listed below.
16100 @defvr {Scheme Variable} system-service-type
16101 This is the root of the service graph. It produces the system directory
16102 as returned by the @command{guix system build} command.
16105 @defvr {Scheme Variable} boot-service-type
16106 The type of the ``boot service'', which produces the @dfn{boot script}.
16107 The boot script is what the initial RAM disk runs when booting.
16110 @defvr {Scheme Variable} etc-service-type
16111 The type of the @file{/etc} service. This service can be extended by
16112 passing it name/file tuples such as:
16115 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16118 In this example, the effect would be to add an @file{/etc/issue} file
16119 pointing to the given file.
16122 @defvr {Scheme Variable} setuid-program-service-type
16123 Type for the ``setuid-program service''. This service collects lists of
16124 executable file names, passed as gexps, and adds them to the set of
16125 setuid-root programs on the system (@pxref{Setuid Programs}).
16128 @defvr {Scheme Variable} profile-service-type
16129 Type of the service that populates the @dfn{system profile}---i.e., the
16130 programs under @file{/run/current-system/profile}. Other services can
16131 extend it by passing it lists of packages to add to the system profile.
16135 @node Shepherd Services
16136 @subsubsection Shepherd Services
16138 @cindex shepherd services
16140 @cindex init system
16141 The @code{(gnu services shepherd)} module provides a way to define
16142 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16143 initialization system---the first process that is started when the
16144 system boots, also known as PID@tie{}1
16145 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16147 Services in the Shepherd can depend on each other. For instance, the
16148 SSH daemon may need to be started after the syslog daemon has been
16149 started, which in turn can only happen once all the file systems have
16150 been mounted. The simple operating system defined earlier (@pxref{Using
16151 the Configuration System}) results in a service graph like this:
16153 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16155 You can actually generate such a graph for any operating system
16156 definition using the @command{guix system shepherd-graph} command
16157 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16159 The @var{%shepherd-root-service} is a service object representing
16160 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16161 by passing it lists of @code{<shepherd-service>} objects.
16163 @deftp {Data Type} shepherd-service
16164 The data type representing a service managed by the Shepherd.
16167 @item @code{provision}
16168 This is a list of symbols denoting what the service provides.
16170 These are the names that may be passed to @command{herd start},
16171 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16172 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16173 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16175 @item @code{requirements} (default: @code{'()})
16176 List of symbols denoting the Shepherd services this one depends on.
16178 @item @code{respawn?} (default: @code{#t})
16179 Whether to restart the service when it stops, for instance when the
16180 underlying process dies.
16183 @itemx @code{stop} (default: @code{#~(const #f)})
16184 The @code{start} and @code{stop} fields refer to the Shepherd's
16185 facilities to start and stop processes (@pxref{Service De- and
16186 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16187 G-expressions that get expanded in the Shepherd configuration file
16188 (@pxref{G-Expressions}).
16190 @item @code{documentation}
16191 A documentation string, as shown when running:
16194 herd doc @var{service-name}
16197 where @var{service-name} is one of the symbols in @var{provision}
16198 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16200 @item @code{modules} (default: @var{%default-modules})
16201 This is the list of modules that must be in scope when @code{start} and
16202 @code{stop} are evaluated.
16207 @defvr {Scheme Variable} shepherd-root-service-type
16208 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16210 This is the service type that extensions target when they want to create
16211 shepherd services (@pxref{Service Types and Services}, for an example).
16212 Each extension must pass a list of @code{<shepherd-service>}.
16215 @defvr {Scheme Variable} %shepherd-root-service
16216 This service represents PID@tie{}1.
16220 @node Documentation
16221 @section Documentation
16223 @cindex documentation, searching for
16224 @cindex searching for documentation
16225 @cindex Info, documentation format
16227 @cindex manual pages
16228 In most cases packages installed with Guix come with documentation.
16229 There are two main documentation formats: ``Info'', a browseable
16230 hypertext format used for GNU software, and ``manual pages'' (or ``man
16231 pages''), the linear documentation format traditionally found on Unix.
16232 Info manuals are accessed with the @command{info} command or with Emacs,
16233 and man pages are accessed using @command{man}.
16235 You can look for documentation of software installed on your system by
16236 keyword. For example, the following command searches for information
16237 about ``TLS'' in Info manuals:
16241 "(emacs)Network Security" -- STARTTLS
16242 "(emacs)Network Security" -- TLS
16243 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16244 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16249 The command below searches for the same keyword in man pages:
16253 SSL (7) - OpenSSL SSL/TLS library
16254 certtool (1) - GnuTLS certificate tool
16258 These searches are purely local to your computer so you have the
16259 guarantee that documentation you find corresponds to what you have
16260 actually installed, you can access it off-line, and your privacy is
16263 Once you have these results, you can view the relevant documentation by
16267 $ info "(gnutls)Core TLS API"
16277 Info manuals contain sections and indices as well as hyperlinks like
16278 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16279 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16280 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16281 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16282 Introduction}, for an introduction to Info navigation.
16284 @node Installing Debugging Files
16285 @section Installing Debugging Files
16287 @cindex debugging files
16288 Program binaries, as produced by the GCC compilers for instance, are
16289 typically written in the ELF format, with a section containing
16290 @dfn{debugging information}. Debugging information is what allows the
16291 debugger, GDB, to map binary code to source code; it is required to
16292 debug a compiled program in good conditions.
16294 The problem with debugging information is that is takes up a fair amount
16295 of disk space. For example, debugging information for the GNU C Library
16296 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16297 debugging info of all the installed programs is usually not an option.
16298 Yet, space savings should not come at the cost of an impediment to
16299 debugging---especially in the GNU system, which should make it easier
16300 for users to exert their computing freedom (@pxref{GNU Distribution}).
16302 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16303 mechanism that allows users to get the best of both worlds: debugging
16304 information can be stripped from the binaries and stored in separate
16305 files. GDB is then able to load debugging information from those files,
16306 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16309 The GNU distribution takes advantage of this by storing debugging
16310 information in the @code{lib/debug} sub-directory of a separate package
16311 output unimaginatively called @code{debug} (@pxref{Packages with
16312 Multiple Outputs}). Users can choose to install the @code{debug} output
16313 of a package when they need it. For instance, the following command
16314 installs the debugging information for the GNU C Library and for GNU
16318 guix package -i glibc:debug guile:debug
16321 GDB must then be told to look for debug files in the user's profile, by
16322 setting the @code{debug-file-directory} variable (consider setting it
16323 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16327 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16330 From there on, GDB will pick up debugging information from the
16331 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16333 In addition, you will most likely want GDB to be able to show the source
16334 code being debugged. To do that, you will have to unpack the source
16335 code of the package of interest (obtained with @code{guix build
16336 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16337 directory using the @code{directory} command (@pxref{Source Path,
16338 @code{directory},, gdb, Debugging with GDB}).
16340 @c XXX: keep me up-to-date
16341 The @code{debug} output mechanism in Guix is implemented by the
16342 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16343 opt-in---debugging information is available only for the packages
16344 with definitions explicitly declaring a @code{debug} output. This may be
16345 changed to opt-out in the future if our build farm servers can handle
16346 the load. To check whether a package has a @code{debug} output, use
16347 @command{guix package --list-available} (@pxref{Invoking guix package}).
16350 @node Security Updates
16351 @section Security Updates
16353 @cindex security updates
16354 @cindex security vulnerabilities
16355 Occasionally, important security vulnerabilities are discovered in software
16356 packages and must be patched. Guix developers try hard to keep track of
16357 known vulnerabilities and to apply fixes as soon as possible in the
16358 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16359 containing only security updates.) The @command{guix lint} tool helps
16360 developers find out about vulnerable versions of software packages in the
16365 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16366 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
16367 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16371 @xref{Invoking guix lint}, for more information.
16374 As of version @value{VERSION}, the feature described below is considered
16378 Guix follows a functional
16379 package management discipline (@pxref{Introduction}), which implies
16380 that, when a package is changed, @emph{every package that depends on it}
16381 must be rebuilt. This can significantly slow down the deployment of
16382 fixes in core packages such as libc or Bash, since basically the whole
16383 distribution would need to be rebuilt. Using pre-built binaries helps
16384 (@pxref{Substitutes}), but deployment may still take more time than
16388 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16389 for fast deployment of critical updates without the costs associated
16390 with a whole-distribution rebuild. The idea is to rebuild only the
16391 package that needs to be patched, and then to ``graft'' it onto packages
16392 explicitly installed by the user and that were previously referring to
16393 the original package. The cost of grafting is typically very low, and
16394 order of magnitudes lower than a full rebuild of the dependency chain.
16396 @cindex replacements of packages, for grafts
16397 For instance, suppose a security update needs to be applied to Bash.
16398 Guix developers will provide a package definition for the ``fixed''
16399 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16400 Packages}). Then, the original package definition is augmented with a
16401 @code{replacement} field pointing to the package containing the bug fix:
16408 (replacement bash-fixed)))
16411 From there on, any package depending directly or indirectly on Bash---as
16412 reported by @command{guix gc --requisites} (@pxref{Invoking guix
16413 gc})---that is installed is automatically ``rewritten'' to refer to
16414 @var{bash-fixed} instead of @var{bash}. This grafting process takes
16415 time proportional to the size of the package, usually less than a
16416 minute for an ``average'' package on a recent machine. Grafting is
16417 recursive: when an indirect dependency requires grafting, then grafting
16418 ``propagates'' up to the package that the user is installing.
16420 Currently, the length of the name and version of the graft and that of
16421 the package it replaces (@var{bash-fixed} and @var{bash} in the example
16422 above) must be equal. This restriction mostly comes from the fact that
16423 grafting works by patching files, including binary files, directly.
16424 Other restrictions may apply: for instance, when adding a graft to a
16425 package providing a shared library, the original shared library and its
16426 replacement must have the same @code{SONAME} and be binary-compatible.
16428 The @option{--no-grafts} command-line option allows you to forcefully
16429 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
16433 guix build bash --no-grafts
16437 returns the store file name of the original Bash, whereas:
16444 returns the store file name of the ``fixed'', replacement Bash. This
16445 allows you to distinguish between the two variants of Bash.
16447 To verify which Bash your whole profile refers to, you can run
16448 (@pxref{Invoking guix gc}):
16451 guix gc -R `readlink -f ~/.guix-profile` | grep bash
16455 @dots{} and compare the store file names that you get with those above.
16456 Likewise for a complete GuixSD system generation:
16459 guix gc -R `guix system build my-config.scm` | grep bash
16462 Lastly, to check which Bash running processes are using, you can use the
16463 @command{lsof} command:
16466 lsof | grep /gnu/store/.*bash
16470 @node Package Modules
16471 @section Package Modules
16473 From a programming viewpoint, the package definitions of the
16474 GNU distribution are provided by Guile modules in the @code{(gnu packages
16475 @dots{})} name space@footnote{Note that packages under the @code{(gnu
16476 packages @dots{})} module name space are not necessarily ``GNU
16477 packages''. This module naming scheme follows the usual Guile module
16478 naming convention: @code{gnu} means that these modules are distributed
16479 as part of the GNU system, and @code{packages} identifies modules that
16480 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
16481 Reference Manual}). For instance, the @code{(gnu packages emacs)}
16482 module exports a variable named @code{emacs}, which is bound to a
16483 @code{<package>} object (@pxref{Defining Packages}).
16485 The @code{(gnu packages @dots{})} module name space is
16486 automatically scanned for packages by the command-line tools. For
16487 instance, when running @code{guix package -i emacs}, all the @code{(gnu
16488 packages @dots{})} modules are scanned until one that exports a package
16489 object whose name is @code{emacs} is found. This package search
16490 facility is implemented in the @code{(gnu packages)} module.
16492 @cindex customization, of packages
16493 @cindex package module search path
16494 Users can store package definitions in modules with different
16495 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
16496 name and module name must match. For instance, the @code{(my-packages
16497 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
16498 relative to the load path specified with @option{--load-path} or
16499 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
16500 guile, GNU Guile Reference Manual}, for details.}. These package definitions
16501 will not be visible by default. Users can invoke commands such as
16502 @command{guix package} and @command{guix build} with the
16503 @code{-e} option so that they know where to find the package. Better
16504 yet, they can use the
16505 @code{-L} option of these commands to make those modules visible
16506 (@pxref{Invoking guix build, @code{--load-path}}), or define the
16507 @code{GUIX_PACKAGE_PATH} environment variable. This environment
16508 variable makes it easy to extend or customize the distribution and is
16509 honored by all the user interfaces.
16511 @defvr {Environment Variable} GUIX_PACKAGE_PATH
16512 This is a colon-separated list of directories to search for additional
16513 package modules. Directories listed in this variable take precedence
16514 over the own modules of the distribution.
16517 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
16518 each package is built based solely on other packages in the
16519 distribution. The root of this dependency graph is a small set of
16520 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
16521 bootstrap)} module. For more information on bootstrapping,
16522 @pxref{Bootstrapping}.
16524 @node Packaging Guidelines
16525 @section Packaging Guidelines
16527 @cindex packages, creating
16528 The GNU distribution is nascent and may well lack some of your favorite
16529 packages. This section describes how you can help make the distribution
16530 grow. @xref{Contributing}, for additional information on how you can
16533 Free software packages are usually distributed in the form of
16534 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
16535 all the source files. Adding a package to the distribution means
16536 essentially two things: adding a @dfn{recipe} that describes how to
16537 build the package, including a list of other packages required to build
16538 it, and adding @dfn{package metadata} along with that recipe, such as a
16539 description and licensing information.
16541 In Guix all this information is embodied in @dfn{package definitions}.
16542 Package definitions provide a high-level view of the package. They are
16543 written using the syntax of the Scheme programming language; in fact,
16544 for each package we define a variable bound to the package definition,
16545 and export that variable from a module (@pxref{Package Modules}).
16546 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
16547 creating packages. For more information on package definitions,
16548 @pxref{Defining Packages}.
16550 Once a package definition is in place, stored in a file in the Guix
16551 source tree, it can be tested using the @command{guix build} command
16552 (@pxref{Invoking guix build}). For example, assuming the new package is
16553 called @code{gnew}, you may run this command from the Guix build tree
16554 (@pxref{Running Guix Before It Is Installed}):
16557 ./pre-inst-env guix build gnew --keep-failed
16560 Using @code{--keep-failed} makes it easier to debug build failures since
16561 it provides access to the failed build tree. Another useful
16562 command-line option when debugging is @code{--log-file}, to access the
16565 If the package is unknown to the @command{guix} command, it may be that
16566 the source file contains a syntax error, or lacks a @code{define-public}
16567 clause to export the package variable. To figure it out, you may load
16568 the module from Guile to get more information about the actual error:
16571 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
16574 Once your package builds correctly, please send us a patch
16575 (@pxref{Contributing}). Well, if you need help, we will be happy to
16576 help you too. Once the patch is committed in the Guix repository, the
16577 new package automatically gets built on the supported platforms by
16578 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
16581 @cindex substituter
16582 Users can obtain the new package definition simply by running
16583 @command{guix pull} (@pxref{Invoking guix pull}). When
16584 @code{hydra.gnu.org} is done building the package, installing the
16585 package automatically downloads binaries from there
16586 (@pxref{Substitutes}). The only place where human intervention is
16587 needed is to review and apply the patch.
16591 * Software Freedom:: What may go into the distribution.
16592 * Package Naming:: What's in a name?
16593 * Version Numbers:: When the name is not enough.
16594 * Synopses and Descriptions:: Helping users find the right package.
16595 * Python Modules:: A touch of British comedy.
16596 * Perl Modules:: Little pearls.
16597 * Java Packages:: Coffee break.
16598 * Fonts:: Fond of fonts.
16601 @node Software Freedom
16602 @subsection Software Freedom
16604 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
16605 @cindex free software
16606 The GNU operating system has been developed so that users can have
16607 freedom in their computing. GNU is @dfn{free software}, meaning that
16608 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
16609 essential freedoms}: to run the program, to study and change the program
16610 in source code form, to redistribute exact copies, and to distribute
16611 modified versions. Packages found in the GNU distribution provide only
16612 software that conveys these four freedoms.
16614 In addition, the GNU distribution follow the
16615 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
16616 software distribution guidelines}. Among other things, these guidelines
16617 reject non-free firmware, recommendations of non-free software, and
16618 discuss ways to deal with trademarks and patents.
16620 Some otherwise free upstream package sources contain a small and optional
16621 subset that violates the above guidelines, for instance because this subset
16622 is itself non-free code. When that happens, the offending items are removed
16623 with appropriate patches or code snippets in the @code{origin} form of the
16624 package (@pxref{Defining Packages}). This way, @code{guix
16625 build --source} returns the ``freed'' source rather than the unmodified
16629 @node Package Naming
16630 @subsection Package Naming
16632 @cindex package name
16633 A package has actually two names associated with it:
16634 First, there is the name of the @emph{Scheme variable}, the one following
16635 @code{define-public}. By this name, the package can be made known in the
16636 Scheme code, for instance as input to another package. Second, there is
16637 the string in the @code{name} field of a package definition. This name
16638 is used by package management commands such as
16639 @command{guix package} and @command{guix build}.
16641 Both are usually the same and correspond to the lowercase conversion of
16642 the project name chosen upstream, with underscores replaced with
16643 hyphens. For instance, GNUnet is available as @code{gnunet}, and
16644 SDL_net as @code{sdl-net}.
16646 We do not add @code{lib} prefixes for library packages, unless these are
16647 already part of the official project name. But @pxref{Python
16648 Modules} and @ref{Perl Modules} for special rules concerning modules for
16649 the Python and Perl languages.
16651 Font package names are handled differently, @pxref{Fonts}.
16654 @node Version Numbers
16655 @subsection Version Numbers
16657 @cindex package version
16658 We usually package only the latest version of a given free software
16659 project. But sometimes, for instance for incompatible library versions,
16660 two (or more) versions of the same package are needed. These require
16661 different Scheme variable names. We use the name as defined
16662 in @ref{Package Naming}
16663 for the most recent version; previous versions use the same name, suffixed
16664 by @code{-} and the smallest prefix of the version number that may
16665 distinguish the two versions.
16667 The name inside the package definition is the same for all versions of a
16668 package and does not contain any version number.
16670 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
16673 (define-public gtk+
16678 (define-public gtk+-2
16681 (version "2.24.20")
16684 If we also wanted GTK+ 3.8.2, this would be packaged as
16686 (define-public gtk+-3.8
16693 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
16694 @c for a discussion of what follows.
16695 @cindex version number, for VCS snapshots
16696 Occasionally, we package snapshots of upstream's version control system
16697 (VCS) instead of formal releases. This should remain exceptional,
16698 because it is up to upstream developers to clarify what the stable
16699 release is. Yet, it is sometimes necessary. So, what should we put in
16700 the @code{version} field?
16702 Clearly, we need to make the commit identifier of the VCS snapshot
16703 visible in the version string, but we also need to make sure that the
16704 version string is monotonically increasing so that @command{guix package
16705 --upgrade} can determine which version is newer. Since commit
16706 identifiers, notably with Git, are not monotonically increasing, we add
16707 a revision number that we increase each time we upgrade to a newer
16708 snapshot. The resulting version string looks like this:
16713 | | `-- upstream commit ID
16715 | `--- Guix package revision
16717 latest upstream version
16720 It is a good idea to strip commit identifiers in the @code{version}
16721 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
16722 aesthetics have a role to play here) as well as problems related to OS
16723 limits such as the maximum shebang length (127 bytes for the Linux
16724 kernel.) It is best to use the full commit identifiers in
16725 @code{origin}s, though, to avoid ambiguities. A typical package
16726 definition may look like this:
16730 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
16731 (revision "1")) ;Guix package revision
16733 (version (string-append "0.9-" revision "."
16734 (string-take commit 7)))
16737 (uri (git-reference
16738 (url "git://example.org/my-package.git")
16740 (sha256 (base32 "1mbikn@dots{}"))
16741 (file-name (string-append "my-package-" version
16747 @node Synopses and Descriptions
16748 @subsection Synopses and Descriptions
16750 @cindex package description
16751 @cindex package synopsis
16752 As we have seen before, each package in GNU@tie{}Guix includes a
16753 synopsis and a description (@pxref{Defining Packages}). Synopses and
16754 descriptions are important: They are what @command{guix package
16755 --search} searches, and a crucial piece of information to help users
16756 determine whether a given package suits their needs. Consequently,
16757 packagers should pay attention to what goes into them.
16759 Synopses must start with a capital letter and must not end with a
16760 period. They must not start with ``a'' or ``the'', which usually does
16761 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
16762 tool that frobs files''. The synopsis should say what the package
16763 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
16764 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
16765 matching a pattern''.
16767 Keep in mind that the synopsis must be meaningful for a very wide
16768 audience. For example, ``Manipulate alignments in the SAM format''
16769 might make sense for a seasoned bioinformatics researcher, but might be
16770 fairly unhelpful or even misleading to a non-specialized audience. It
16771 is a good idea to come up with a synopsis that gives an idea of the
16772 application domain of the package. In this example, this might give
16773 something like ``Manipulate nucleotide sequence alignments'', which
16774 hopefully gives the user a better idea of whether this is what they are
16777 Descriptions should take between five and ten lines. Use full
16778 sentences, and avoid using acronyms without first introducing them.
16779 Please avoid marketing phrases such as ``world-leading'',
16780 ``industrial-strength'', and ``next-generation'', and avoid superlatives
16781 like ``the most advanced''---they are not helpful to users looking for a
16782 package and may even sound suspicious. Instead, try to be factual,
16783 mentioning use cases and features.
16785 @cindex Texinfo markup, in package descriptions
16786 Descriptions can include Texinfo markup, which is useful to introduce
16787 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
16788 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
16789 should be careful when using some characters for example @samp{@@} and
16790 curly braces which are the basic special characters in Texinfo
16791 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
16792 such as @command{guix package --show} take care of rendering it
16795 Synopses and descriptions are translated by volunteers
16796 @uref{http://translationproject.org/domain/guix-packages.html, at the
16797 Translation Project} so that as many users as possible can read them in
16798 their native language. User interfaces search them and display them in
16799 the language specified by the current locale.
16801 Translation is a lot of work so, as a packager, please pay even more
16802 attention to your synopses and descriptions as every change may entail
16803 additional work for translators. In order to help them, it is possible
16804 to make recommendations or instructions visible to them by inserting
16805 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
16809 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
16810 (description "ARandR is designed to provide a simple visual front end
16811 for the X11 resize-and-rotate (RandR) extension. @dots{}")
16815 @node Python Modules
16816 @subsection Python Modules
16819 We currently package Python 2 and Python 3, under the Scheme variable names
16820 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
16821 To avoid confusion and naming clashes with other programming languages, it
16822 seems desirable that the name of a package for a Python module contains
16823 the word @code{python}.
16825 Some modules are compatible with only one version of Python, others with both.
16826 If the package Foo compiles only with Python 3, we name it
16827 @code{python-foo}; if it compiles only with Python 2, we name it
16828 @code{python2-foo}. If it is compatible with both versions, we create two
16829 packages with the corresponding names.
16831 If a project already contains the word @code{python}, we drop this;
16832 for instance, the module python-dateutil is packaged under the names
16833 @code{python-dateutil} and @code{python2-dateutil}. If the project name
16834 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
16837 @subsubsection Specifying Dependencies
16838 @cindex inputs, for Python packages
16840 Dependency information for Python packages is usually available in the
16841 package source tree, with varying degrees of accuracy: in the
16842 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
16844 Your mission, when writing a recipe for a Python package, is to map
16845 these dependencies to the appropriate type of ``input'' (@pxref{package
16846 Reference, inputs}). Although the @code{pypi} importer normally does a
16847 good job (@pxref{Invoking guix import}), you may want to check the
16848 following check list to determine which dependency goes where.
16853 We currently package Python 2 with @code{setuptools} and @code{pip}
16854 installed like Python 3.4 has per default. Thus you don't need to
16855 specify either of these as an input. @command{guix lint} will warn you
16859 Python dependencies required at run time go into
16860 @code{propagated-inputs}. They are typically defined with the
16861 @code{install_requires} keyword in @file{setup.py}, or in the
16862 @file{requirements.txt} file.
16865 Python packages required only at build time---e.g., those listed with
16866 the @code{setup_requires} keyword in @file{setup.py}---or only for
16867 testing---e.g., those in @code{tests_require}---go into
16868 @code{native-inputs}. The rationale is that (1) they do not need to be
16869 propagated because they are not needed at run time, and (2) in a
16870 cross-compilation context, it's the ``native'' input that we'd want.
16872 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
16873 frameworks. Of course if any of these packages is also required at
16874 run-time, it needs to go to @code{propagated-inputs}.
16877 Anything that does not fall in the previous categories goes to
16878 @code{inputs}, for example programs or C libraries required for building
16879 Python packages containing C extensions.
16882 If a Python package has optional dependencies (@code{extras_require}),
16883 it is up to you to decide whether to add them or not, based on their
16884 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
16891 @subsection Perl Modules
16894 Perl programs standing for themselves are named as any other package,
16895 using the lowercase upstream name.
16896 For Perl packages containing a single class, we use the lowercase class name,
16897 replace all occurrences of @code{::} by dashes and prepend the prefix
16899 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
16900 Modules containing several classes keep their lowercase upstream name and
16901 are also prepended by @code{perl-}. Such modules tend to have the word
16902 @code{perl} somewhere in their name, which gets dropped in favor of the
16903 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
16906 @node Java Packages
16907 @subsection Java Packages
16910 Java programs standing for themselves are named as any other package,
16911 using the lowercase upstream name.
16913 To avoid confusion and naming clashes with other programming languages,
16914 it is desirable that the name of a package for a Java package is
16915 prefixed with @code{java-}. If a project already contains the word
16916 @code{java}, we drop this; for instance, the package @code{ngsjava} is
16917 packaged under the name @code{java-ngs}.
16919 For Java packages containing a single class or a small class hierarchy,
16920 we use the lowercase class name, replace all occurrences of @code{.} by
16921 dashes and prepend the prefix @code{java-}. So the class
16922 @code{apache.commons.cli} becomes package
16923 @code{java-apache-commons-cli}.
16930 For fonts that are in general not installed by a user for typesetting
16931 purposes, or that are distributed as part of a larger software package,
16932 we rely on the general packaging rules for software; for instance, this
16933 applies to the fonts delivered as part of the X.Org system or fonts that
16934 are part of TeX Live.
16936 To make it easier for a user to search for fonts, names for other packages
16937 containing only fonts are constructed as follows, independently of the
16938 upstream package name.
16940 The name of a package containing only one font family starts with
16941 @code{font-}; it is followed by the foundry name and a dash @code{-}
16942 if the foundry is known, and the font family name, in which spaces are
16943 replaced by dashes (and as usual, all upper case letters are transformed
16945 For example, the Gentium font family by SIL is packaged under the name
16946 @code{font-sil-gentium}.
16948 For a package containing several font families, the name of the collection
16949 is used in the place of the font family name.
16950 For instance, the Liberation fonts consist of three families,
16951 Liberation Sans, Liberation Serif and Liberation Mono.
16952 These could be packaged separately under the names
16953 @code{font-liberation-sans} and so on; but as they are distributed together
16954 under a common name, we prefer to package them together as
16955 @code{font-liberation}.
16957 In the case where several formats of the same font family or font collection
16958 are packaged separately, a short form of the format, prepended by a dash,
16959 is added to the package name. We use @code{-ttf} for TrueType fonts,
16960 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
16965 @node Bootstrapping
16966 @section Bootstrapping
16968 @c Adapted from the ELS 2013 paper.
16970 @cindex bootstrapping
16972 Bootstrapping in our context refers to how the distribution gets built
16973 ``from nothing''. Remember that the build environment of a derivation
16974 contains nothing but its declared inputs (@pxref{Introduction}). So
16975 there's an obvious chicken-and-egg problem: how does the first package
16976 get built? How does the first compiler get compiled? Note that this is
16977 a question of interest only to the curious hacker, not to the regular
16978 user, so you can shamelessly skip this section if you consider yourself
16979 a ``regular user''.
16981 @cindex bootstrap binaries
16982 The GNU system is primarily made of C code, with libc at its core. The
16983 GNU build system itself assumes the availability of a Bourne shell and
16984 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
16985 `grep'. Furthermore, build programs---programs that run
16986 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
16987 (@pxref{Derivations}). Consequently, to be able to build anything at
16988 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
16989 Binutils, libc, and the other packages mentioned above---the
16990 @dfn{bootstrap binaries}.
16992 These bootstrap binaries are ``taken for granted'', though we can also
16993 re-create them if needed (more on that later).
16995 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
16997 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
16998 @c large image, it's hard to scroll. Oh well.
16999 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17001 The figure above shows the very beginning of the dependency graph of the
17002 distribution, corresponding to the package definitions of the @code{(gnu
17003 packages bootstrap)} module. A similar figure can be generated with
17004 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17007 guix graph -t derivation \
17008 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17012 At this level of detail, things are
17013 slightly complex. First, Guile itself consists of an ELF executable,
17014 along with many source and compiled Scheme files that are dynamically
17015 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17016 tarball shown in this graph. This tarball is part of Guix's ``source''
17017 distribution, and gets inserted into the store with @code{add-to-store}
17018 (@pxref{The Store}).
17020 But how do we write a derivation that unpacks this tarball and adds it
17021 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17022 derivation---the first one that gets built---uses @code{bash} as its
17023 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17024 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17025 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17026 the Guix source distribution, whose sole purpose is to allow the Guile
17027 tarball to be unpacked.
17029 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17030 Guile that can be used to run subsequent build programs. Its first task
17031 is to download tarballs containing the other pre-built binaries---this
17032 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17033 @code{ftp-client.scm} are used for this purpose. The
17034 @code{module-import.drv} derivations import those modules in a directory
17035 in the store, using the original layout. The
17036 @code{module-import-compiled.drv} derivations compile those modules, and
17037 write them in an output directory with the right layout. This
17038 corresponds to the @code{#:modules} argument of
17039 @code{build-expression->derivation} (@pxref{Derivations}).
17041 Finally, the various tarballs are unpacked by the
17042 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17043 etc., at which point we have a working C tool chain.
17046 @unnumberedsubsec Building the Build Tools
17048 Bootstrapping is complete when we have a full tool chain that does not
17049 depend on the pre-built bootstrap tools discussed above. This
17050 no-dependency requirement is verified by checking whether the files of
17051 the final tool chain contain references to the @file{/gnu/store}
17052 directories of the bootstrap inputs. The process that leads to this
17053 ``final'' tool chain is described by the package definitions found in
17054 the @code{(gnu packages commencement)} module.
17056 The @command{guix graph} command allows us to ``zoom out'' compared to
17057 the graph above, by looking at the level of package objects instead of
17058 individual derivations---remember that a package may translate to
17059 several derivations, typically one derivation to download its source,
17060 one to build the Guile modules it needs, and one to actually build the
17061 package from source. The command:
17064 guix graph -t bag \
17065 -e '(@@@@ (gnu packages commencement)
17066 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17070 produces the dependency graph leading to the ``final'' C
17071 library@footnote{You may notice the @code{glibc-intermediate} label,
17072 suggesting that it is not @emph{quite} final, but as a good
17073 approximation, we will consider it final.}, depicted below.
17075 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17077 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17078 The first tool that gets built with the bootstrap binaries is
17079 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17080 for all the following packages. From there Findutils and Diffutils get
17083 Then come the first-stage Binutils and GCC, built as pseudo cross
17084 tools---i.e., with @code{--target} equal to @code{--host}. They are
17085 used to build libc. Thanks to this cross-build trick, this libc is
17086 guaranteed not to hold any reference to the initial tool chain.
17088 From there the final Binutils and GCC (not shown above) are built.
17090 from the final Binutils, and links programs against the just-built libc.
17091 This tool chain is used to build the other packages used by Guix and by
17092 the GNU Build System: Guile, Bash, Coreutils, etc.
17094 And voilà! At this point we have the complete set of build tools that
17095 the GNU Build System expects. These are in the @code{%final-inputs}
17096 variable of the @code{(gnu packages commencement)} module, and are
17097 implicitly used by any package that uses @code{gnu-build-system}
17098 (@pxref{Build Systems, @code{gnu-build-system}}).
17101 @unnumberedsubsec Building the Bootstrap Binaries
17103 @cindex bootstrap binaries
17104 Because the final tool chain does not depend on the bootstrap binaries,
17105 those rarely need to be updated. Nevertheless, it is useful to have an
17106 automated way to produce them, should an update occur, and this is what
17107 the @code{(gnu packages make-bootstrap)} module provides.
17109 The following command builds the tarballs containing the bootstrap
17110 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17111 of Coreutils and other basic command-line tools):
17114 guix build bootstrap-tarballs
17117 The generated tarballs are those that should be referred to in the
17118 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17121 Still here? Then perhaps by now you've started to wonder: when do we
17122 reach a fixed point? That is an interesting question! The answer is
17123 unknown, but if you would like to investigate further (and have
17124 significant computational and storage resources to do so), then let us
17128 @section Porting to a New Platform
17130 As discussed above, the GNU distribution is self-contained, and
17131 self-containment is achieved by relying on pre-built ``bootstrap
17132 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17133 operating system kernel, CPU architecture, and application binary
17134 interface (ABI). Thus, to port the distribution to a platform that is
17135 not yet supported, one must build those bootstrap binaries, and update
17136 the @code{(gnu packages bootstrap)} module to use them on that platform.
17138 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17139 When everything goes well, and assuming the GNU tool chain supports the
17140 target platform, this can be as simple as running a command like this
17144 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17147 For this to work, the @code{glibc-dynamic-linker} procedure in
17148 @code{(gnu packages bootstrap)} must be augmented to return the right
17149 file name for libc's dynamic linker on that platform; likewise,
17150 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17151 taught about the new platform.
17153 Once these are built, the @code{(gnu packages bootstrap)} module needs
17154 to be updated to refer to these binaries on the target platform. That
17155 is, the hashes and URLs of the bootstrap tarballs for the new platform
17156 must be added alongside those of the currently supported platforms. The
17157 bootstrap Guile tarball is treated specially: it is expected to be
17158 available locally, and @file{gnu/local.mk} has rules do download it for
17159 the supported architectures; a rule for the new platform must be added
17162 In practice, there may be some complications. First, it may be that the
17163 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17164 above) is not recognized by all the GNU tools. Typically, glibc
17165 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17166 configure flag (see @code{gcc.scm} for examples of how to handle this).
17167 Second, some of the required packages could fail to build for that
17168 platform. Lastly, the generated binaries could be broken for some
17171 @c *********************************************************************
17172 @include contributing.texi
17174 @c *********************************************************************
17175 @node Acknowledgments
17176 @chapter Acknowledgments
17178 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17179 which was designed and
17180 implemented by Eelco Dolstra, with contributions from other people (see
17181 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17182 management, and promoted unprecedented features, such as transactional
17183 package upgrades and rollbacks, per-user profiles, and referentially
17184 transparent build processes. Without this work, Guix would not exist.
17186 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17187 an inspiration for Guix.
17189 GNU@tie{}Guix itself is a collective work with contributions from a
17190 number of people. See the @file{AUTHORS} file in Guix for more
17191 information on these fine people. The @file{THANKS} file lists people
17192 who have helped by reporting bugs, taking care of the infrastructure,
17193 providing artwork and themes, making suggestions, and more---thank you!
17196 @c *********************************************************************
17197 @node GNU Free Documentation License
17198 @appendix GNU Free Documentation License
17199 @cindex license, GNU Free Documentation License
17200 @include fdl-1.3.texi
17202 @c *********************************************************************
17203 @node Concept Index
17204 @unnumbered Concept Index
17207 @node Programming Index
17208 @unnumbered Programming Index
17209 @syncodeindex tp fn
17210 @syncodeindex vr fn
17215 @c Local Variables:
17216 @c ispell-local-dictionary: "american";