6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
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13 @set OPENPGP-SIGNING-KEY-ID 3CE464558A84FDC69DB40CFB090B11993D9AEBB5
16 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès@*
17 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
18 Copyright @copyright{} 2013 Nikita Karetnikov@*
19 Copyright @copyright{} 2014, 2015, 2016 Alex Kost@*
20 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
21 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
22 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
23 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
24 Copyright @copyright{} 2015, 2016 Ricardo Wurmus@*
25 Copyright @copyright{} 2016 Ben Woodcroft@*
26 Copyright @copyright{} 2016 Chris Marusich@*
27 Copyright @copyright{} 2016, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert@*
38 Copyright @copyright{} 2017 humanitiesNerd@*
39 Copyright @copyright{} 2017 Christopher Allan Webber@*
40 Copyright @copyright{} 2017 Marius Bakke
42 Permission is granted to copy, distribute and/or modify this document
43 under the terms of the GNU Free Documentation License, Version 1.3 or
44 any later version published by the Free Software Foundation; with no
45 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
46 copy of the license is included in the section entitled ``GNU Free
47 Documentation License''.
50 @dircategory System administration
52 * Guix: (guix). Manage installed software and system configuration.
53 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
54 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
55 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
56 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
59 @dircategory Software development
61 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
62 * guix build: (guix)Invoking guix build. Building packages.
63 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
67 @title GNU Guix Reference Manual
68 @subtitle Using the GNU Guix Functional Package Manager
69 @author The GNU Guix Developers
72 @vskip 0pt plus 1filll
73 Edition @value{EDITION} @*
81 @c *********************************************************************
85 This document describes GNU Guix version @value{VERSION}, a functional
86 package management tool written for the GNU system.
89 * Introduction:: What is Guix about?
90 * Installation:: Installing Guix.
91 * Package Management:: Package installation, upgrade, etc.
92 * Programming Interface:: Using Guix in Scheme.
93 * Utilities:: Package management commands.
94 * GNU Distribution:: Software for your friendly GNU system.
95 * Contributing:: Your help needed!
97 * Acknowledgments:: Thanks!
98 * GNU Free Documentation License:: The license of this manual.
99 * Concept Index:: Concepts.
100 * Programming Index:: Data types, functions, and variables.
103 --- The Detailed Node Listing ---
107 * Binary Installation:: Getting Guix running in no time!
108 * Requirements:: Software needed to build and run Guix.
109 * Running the Test Suite:: Testing Guix.
110 * Setting Up the Daemon:: Preparing the build daemon's environment.
111 * Invoking guix-daemon:: Running the build daemon.
112 * Application Setup:: Application-specific setup.
114 Setting Up the Daemon
116 * Build Environment Setup:: Preparing the isolated build environment.
117 * Daemon Offload Setup:: Offloading builds to remote machines.
121 * Features:: How Guix will make your life brighter.
122 * Invoking guix package:: Package installation, removal, etc.
123 * Substitutes:: Downloading pre-built binaries.
124 * Packages with Multiple Outputs:: Single source package, multiple outputs.
125 * Invoking guix gc:: Running the garbage collector.
126 * Invoking guix pull:: Fetching the latest Guix and distribution.
127 * Invoking guix pack:: Creating software bundles.
128 * Invoking guix archive:: Exporting and importing store files.
130 Programming Interface
132 * Defining Packages:: Defining new packages.
133 * Build Systems:: Specifying how packages are built.
134 * The Store:: Manipulating the package store.
135 * Derivations:: Low-level interface to package derivations.
136 * The Store Monad:: Purely functional interface to the store.
137 * G-Expressions:: Manipulating build expressions.
141 * package Reference:: The package data type.
142 * origin Reference:: The origin data type.
146 * Invoking guix build:: Building packages from the command line.
147 * Invoking guix edit:: Editing package definitions.
148 * Invoking guix download:: Downloading a file and printing its hash.
149 * Invoking guix hash:: Computing the cryptographic hash of a file.
150 * Invoking guix import:: Importing package definitions.
151 * Invoking guix refresh:: Updating package definitions.
152 * Invoking guix lint:: Finding errors in package definitions.
153 * Invoking guix size:: Profiling disk usage.
154 * Invoking guix graph:: Visualizing the graph of packages.
155 * Invoking guix environment:: Setting up development environments.
156 * Invoking guix publish:: Sharing substitutes.
157 * Invoking guix challenge:: Challenging substitute servers.
158 * Invoking guix copy:: Copying to and from a remote store.
159 * Invoking guix container:: Process isolation.
161 Invoking @command{guix build}
163 * Common Build Options:: Build options for most commands.
164 * Package Transformation Options:: Creating variants of packages.
165 * Additional Build Options:: Options specific to 'guix build'.
169 * System Installation:: Installing the whole operating system.
170 * System Configuration:: Configuring the operating system.
171 * Documentation:: Browsing software user manuals.
172 * Installing Debugging Files:: Feeding the debugger.
173 * Security Updates:: Deploying security fixes quickly.
174 * Package Modules:: Packages from the programmer's viewpoint.
175 * Packaging Guidelines:: Growing the distribution.
176 * Bootstrapping:: GNU/Linux built from scratch.
177 * Porting:: Targeting another platform or kernel.
181 * Limitations:: What you can expect.
182 * Hardware Considerations:: Supported hardware.
183 * USB Stick Installation:: Preparing the installation medium.
184 * Preparing for Installation:: Networking, partitioning, etc.
185 * Proceeding with the Installation:: The real thing.
186 * Installing GuixSD in a VM:: GuixSD playground.
187 * Building the Installation Image:: How this comes to be.
191 * Using the Configuration System:: Customizing your GNU system.
192 * operating-system Reference:: Detail of operating-system declarations.
193 * File Systems:: Configuring file system mounts.
194 * Mapped Devices:: Block device extra processing.
195 * User Accounts:: Specifying user accounts.
196 * Locales:: Language and cultural convention settings.
197 * Services:: Specifying system services.
198 * Setuid Programs:: Programs running with root privileges.
199 * X.509 Certificates:: Authenticating HTTPS servers.
200 * Name Service Switch:: Configuring libc's name service switch.
201 * Initial RAM Disk:: Linux-Libre bootstrapping.
202 * GRUB Configuration:: Configuring the boot loader.
203 * Invoking guix system:: Instantiating a system configuration.
204 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
205 * Defining Services:: Adding new service definitions.
209 * Base Services:: Essential system services.
210 * Scheduled Job Execution:: The mcron service.
211 * Log Rotation:: The rottlog service.
212 * Networking Services:: Network setup, SSH daemon, etc.
213 * X Window:: Graphical display.
214 * Printing Services:: Local and remote printer support.
215 * Desktop Services:: D-Bus and desktop services.
216 * Database Services:: SQL databases.
217 * Mail Services:: IMAP, POP3, SMTP, and all that.
218 * Messaging Services:: Messaging services.
219 * Kerberos Services:: Kerberos services.
220 * Web Services:: Web servers.
221 * VPN Services:: VPN daemons.
222 * Network File System:: NFS related services.
223 * Continuous Integration:: The Cuirass service.
224 * Power management Services:: The TLP tool.
225 * Miscellaneous Services:: Other services.
229 * Service Composition:: The model for composing services.
230 * Service Types and Services:: Types and services.
231 * Service Reference:: API reference.
232 * Shepherd Services:: A particular type of service.
236 * Software Freedom:: What may go into the distribution.
237 * Package Naming:: What's in a name?
238 * Version Numbers:: When the name is not enough.
239 * Synopses and Descriptions:: Helping users find the right package.
240 * Python Modules:: A touch of British comedy.
241 * Perl Modules:: Little pearls.
242 * Java Packages:: Coffee break.
243 * Fonts:: Fond of fonts.
247 * Building from Git:: The latest and greatest.
248 * Running Guix Before It Is Installed:: Hacker tricks.
249 * The Perfect Setup:: The right tools.
250 * Coding Style:: Hygiene of the contributor.
251 * Submitting Patches:: Share your work.
255 * Programming Paradigm:: How to compose your elements.
256 * Modules:: Where to store your code?
257 * Data Types and Pattern Matching:: Implementing data structures.
258 * Formatting Code:: Writing conventions.
263 @c *********************************************************************
265 @chapter Introduction
268 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
269 using the international phonetic alphabet (IPA).} is a package
270 management tool for the GNU system. Guix makes it easy for unprivileged
271 users to install, upgrade, or remove packages, to roll back to a
272 previous package set, to build packages from source, and generally
273 assists with the creation and maintenance of software environments.
275 @cindex user interfaces
276 Guix provides a command-line package management interface
277 (@pxref{Invoking guix package}), a set of command-line utilities
278 (@pxref{Utilities}), as well as Scheme programming interfaces
279 (@pxref{Programming Interface}).
281 Its @dfn{build daemon} is responsible for building packages on behalf of
282 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
283 binaries from authorized sources (@pxref{Substitutes}).
285 @cindex extensibility of the distribution
286 @cindex customization, of packages
287 Guix includes package definitions for many GNU and non-GNU packages, all
288 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
289 user's computing freedom}. It is @emph{extensible}: users can write
290 their own package definitions (@pxref{Defining Packages}) and make them
291 available as independent package modules (@pxref{Package Modules}). It
292 is also @emph{customizable}: users can @emph{derive} specialized package
293 definitions from existing ones, including from the command line
294 (@pxref{Package Transformation Options}).
296 @cindex Guix System Distribution
298 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
299 where it complements the available tools without interference
300 (@pxref{Installation}), or you can use it as part of the standalone
301 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
302 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
303 system configuration and Guix takes care of instantiating the
304 configuration in a transactional, reproducible, and stateless fashion
305 (@pxref{System Configuration}).
307 @cindex functional package management
308 Under the hood, Guix implements the @dfn{functional package management}
309 discipline pioneered by Nix (@pxref{Acknowledgments}).
310 In Guix, the package build and installation process is seen
311 as a @emph{function}, in the mathematical sense. That function takes inputs,
312 such as build scripts, a compiler, and libraries, and
313 returns an installed package. As a pure function, its result depends
314 solely on its inputs---for instance, it cannot refer to software or
315 scripts that were not explicitly passed as inputs. A build function
316 always produces the same result when passed a given set of inputs. It
317 cannot alter the environment of the running system in
318 any way; for instance, it cannot create, modify, or delete files outside
319 of its build and installation directories. This is achieved by running
320 build processes in isolated environments (or @dfn{containers}), where only their
321 explicit inputs are visible.
324 The result of package build functions is @dfn{cached} in the file
325 system, in a special directory called @dfn{the store} (@pxref{The
326 Store}). Each package is installed in a directory of its own in the
327 store---by default under @file{/gnu/store}. The directory name contains
328 a hash of all the inputs used to build that package; thus, changing an
329 input yields a different directory name.
331 This approach is the foundation for the salient features of Guix: support
332 for transactional package upgrade and rollback, per-user installation, and
333 garbage collection of packages (@pxref{Features}).
336 @c *********************************************************************
338 @chapter Installation
340 @cindex installing Guix
341 GNU Guix is available for download from its website at
342 @url{http://www.gnu.org/software/guix/}. This section describes the
343 software requirements of Guix, as well as how to install it and get
346 Note that this section is concerned with the installation of the package
347 manager, which can be done on top of a running GNU/Linux system. If,
348 instead, you want to install the complete GNU operating system,
349 @pxref{System Installation}.
351 @cindex foreign distro
352 When installed on a running GNU/Linux system---thereafter called a
353 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
354 without interference. Its data lives exclusively in two directories,
355 usually @file{/gnu/store} and @file{/var/guix}; other files on your
356 system, such as @file{/etc}, are left untouched.
358 Once installed, Guix can be updated by running @command{guix pull}
359 (@pxref{Invoking guix pull}).
362 * Binary Installation:: Getting Guix running in no time!
363 * Requirements:: Software needed to build and run Guix.
364 * Running the Test Suite:: Testing Guix.
365 * Setting Up the Daemon:: Preparing the build daemon's environment.
366 * Invoking guix-daemon:: Running the build daemon.
367 * Application Setup:: Application-specific setup.
370 @node Binary Installation
371 @section Binary Installation
373 @cindex installing Guix from binaries
374 This section describes how to install Guix on an arbitrary system from a
375 self-contained tarball providing binaries for Guix and for all its
376 dependencies. This is often quicker than installing from source, which
377 is described in the next sections. The only requirement is to have
380 Installing goes along these lines:
384 @cindex downloading Guix binary
385 Download the binary tarball from
386 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
387 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
388 already running the kernel Linux, and so on.
390 @c The following is somewhat duplicated in ``System Installation''.
391 Make sure to download the associated @file{.sig} file and to verify the
392 authenticity of the tarball against it, along these lines:
395 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
396 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
399 If that command fails because you do not have the required public key,
400 then run this command to import it:
403 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
407 and rerun the @code{gpg --verify} command.
408 @c end authentication part
415 # tar --warning=no-timestamp -xf \
416 guix-binary-@value{VERSION}.@var{system}.tar.xz
417 # mv var/guix /var/ && mv gnu /
420 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
421 The latter contains a ready-to-use profile for @code{root} (see next
424 Do @emph{not} unpack the tarball on a working Guix system since that
425 would overwrite its own essential files.
427 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
428 not emit warnings about ``implausibly old time stamps'' (such
429 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
431 They stem from the fact that all the
432 files in the archive have their modification time set to zero (which
433 means January 1st, 1970.) This is done on purpose to make sure the
434 archive content is independent of its creation time, thus making it
438 Make @code{root}'s profile available under @file{~/.guix-profile}:
441 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
445 Source @file{etc/profile} to augment @code{PATH} and other relevant
446 environment variables:
449 # GUIX_PROFILE=$HOME/.guix-profile \
450 source $GUIX_PROFILE/etc/profile
454 Create the group and user accounts for build users as explained below
455 (@pxref{Build Environment Setup}).
458 Run the daemon, and set it to automatically start on boot.
460 If your host distro uses the systemd init system, this can be achieved
463 @c Versions of systemd that supported symlinked service files are not
464 @c yet widely deployed, so we should suggest that users copy the service
467 @c See this thread for more information:
468 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
471 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
473 # systemctl start guix-daemon && systemctl enable guix-daemon
476 If your host distro uses the Upstart init system:
479 # initctl reload-configuration
480 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
484 Otherwise, you can still start the daemon manually with:
487 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
491 Make the @command{guix} command available to other users on the machine,
495 # mkdir -p /usr/local/bin
497 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
500 It is also a good idea to make the Info version of this manual available
504 # mkdir -p /usr/local/share/info
505 # cd /usr/local/share/info
506 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
510 That way, assuming @file{/usr/local/share/info} is in the search path,
511 running @command{info guix} will open this manual (@pxref{Other Info
512 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
516 @cindex substitutes, authorization thereof
517 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
518 (@pxref{Substitutes}), authorize them:
521 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
525 Each user may need to perform a few additional steps to make their Guix
526 environment ready for use, @pxref{Application Setup}.
529 Voilà, the installation is complete!
531 You can confirm that Guix is working by installing a sample package into
535 # guix package -i hello
538 The @code{guix} package must remain available in @code{root}'s profile,
539 or it would become subject to garbage collection---in which case you
540 would find yourself badly handicapped by the lack of the @command{guix}
541 command. In other words, do not remove @code{guix} by running
542 @code{guix package -r guix}.
544 The binary installation tarball can be (re)produced and verified simply
545 by running the following command in the Guix source tree:
548 make guix-binary.@var{system}.tar.xz
552 ... which, in turn, runs:
555 guix pack -s @var{system} --localstatedir guix
558 @xref{Invoking guix pack}, for more info on this handy tool.
561 @section Requirements
563 This section lists requirements when building Guix from source. The
564 build procedure for Guix is the same as for other GNU software, and is
565 not covered here. Please see the files @file{README} and @file{INSTALL}
566 in the Guix source tree for additional details.
568 GNU Guix depends on the following packages:
571 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
572 later, including 2.2.x;
573 @item @url{http://gnupg.org/, GNU libgcrypt};
575 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
576 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
577 Guile,, gnutls-guile, GnuTLS-Guile});
578 @item @url{http://www.gnu.org/software/make/, GNU Make}.
581 The following dependencies are optional:
586 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
587 allow you to use the @command{guix import pypi} command (@pxref{Invoking
588 guix import}). It is of
589 interest primarily for developers and not for casual users.
592 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
593 Support for build offloading (@pxref{Daemon Offload Setup}) and
594 @command{guix copy} (@pxref{Invoking guix copy}) depends on
595 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
596 version 0.10.2 or later.
599 When @url{http://zlib.net, zlib} is available, @command{guix publish}
600 can compress build byproducts (@pxref{Invoking guix publish}).
603 Unless @code{--disable-daemon} was passed to @command{configure}, the
604 following packages are also needed:
607 @item @url{http://sqlite.org, SQLite 3};
608 @item @url{http://www.bzip.org, libbz2};
609 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
613 @cindex state directory
614 When configuring Guix on a system that already has a Guix installation,
615 be sure to specify the same state directory as the existing installation
616 using the @code{--localstatedir} option of the @command{configure}
617 script (@pxref{Directory Variables, @code{localstatedir},, standards,
618 GNU Coding Standards}). The @command{configure} script protects against
619 unintended misconfiguration of @var{localstatedir} so you do not
620 inadvertently corrupt your store (@pxref{The Store}).
622 @cindex Nix, compatibility
623 When a working installation of @url{http://nixos.org/nix/, the Nix package
624 manager} is available, you
625 can instead configure Guix with @code{--disable-daemon}. In that case,
626 Nix replaces the three dependencies above.
628 Guix is compatible with Nix, so it is possible to share the same store
629 between both. To do so, you must pass @command{configure} not only the
630 same @code{--with-store-dir} value, but also the same
631 @code{--localstatedir} value. The latter is essential because it
632 specifies where the database that stores metadata about the store is
633 located, among other things. The default values for Nix are
634 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
635 Note that @code{--disable-daemon} is not required if
636 your goal is to share the store with Nix.
638 @node Running the Test Suite
639 @section Running the Test Suite
642 After a successful @command{configure} and @code{make} run, it is a good
643 idea to run the test suite. It can help catch issues with the setup or
644 environment, or bugs in Guix itself---and really, reporting test
645 failures is a good way to help improve the software. To run the test
652 Test cases can run in parallel: you can use the @code{-j} option of
653 GNU@tie{}make to speed things up. The first run may take a few minutes
654 on a recent machine; subsequent runs will be faster because the store
655 that is created for test purposes will already have various things in
658 It is also possible to run a subset of the tests by defining the
659 @code{TESTS} makefile variable as in this example:
662 make check TESTS="tests/store.scm tests/cpio.scm"
665 By default, tests results are displayed at a file level. In order to
666 see the details of every individual test cases, it is possible to define
667 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
670 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
673 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
674 @file{test-suite.log} file. Please specify the Guix version being used
675 as well as version numbers of the dependencies (@pxref{Requirements}) in
678 Guix also comes with a whole-system test suite that tests complete
679 GuixSD operating system instances. It can only run on systems where
680 Guix is already installed, using:
687 or, again, by defining @code{TESTS} to select a subset of tests to run:
690 make check-system TESTS="basic mcron"
693 These system tests are defined in the @code{(gnu tests @dots{})}
694 modules. They work by running the operating systems under test with
695 lightweight instrumentation in a virtual machine (VM). They can be
696 computationally intensive or rather cheap, depending on whether
697 substitutes are available for their dependencies (@pxref{Substitutes}).
698 Some of them require a lot of storage space to hold VM images.
700 Again in case of test failures, please send @email{bug-guix@@gnu.org}
703 @node Setting Up the Daemon
704 @section Setting Up the Daemon
707 Operations such as building a package or running the garbage collector
708 are all performed by a specialized process, the @dfn{build daemon}, on
709 behalf of clients. Only the daemon may access the store and its
710 associated database. Thus, any operation that manipulates the store
711 goes through the daemon. For instance, command-line tools such as
712 @command{guix package} and @command{guix build} communicate with the
713 daemon (@i{via} remote procedure calls) to instruct it what to do.
715 The following sections explain how to prepare the build daemon's
716 environment. See also @ref{Substitutes}, for information on how to allow
717 the daemon to download pre-built binaries.
720 * Build Environment Setup:: Preparing the isolated build environment.
721 * Daemon Offload Setup:: Offloading builds to remote machines.
724 @node Build Environment Setup
725 @subsection Build Environment Setup
727 @cindex build environment
728 In a standard multi-user setup, Guix and its daemon---the
729 @command{guix-daemon} program---are installed by the system
730 administrator; @file{/gnu/store} is owned by @code{root} and
731 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
732 Guix tools to build packages or otherwise access the store, and the
733 daemon will do it on their behalf, ensuring that the store is kept in a
734 consistent state, and allowing built packages to be shared among users.
737 When @command{guix-daemon} runs as @code{root}, you may not want package
738 build processes themselves to run as @code{root} too, for obvious
739 security reasons. To avoid that, a special pool of @dfn{build users}
740 should be created for use by build processes started by the daemon.
741 These build users need not have a shell and a home directory: they will
742 just be used when the daemon drops @code{root} privileges in build
743 processes. Having several such users allows the daemon to launch
744 distinct build processes under separate UIDs, which guarantees that they
745 do not interfere with each other---an essential feature since builds are
746 regarded as pure functions (@pxref{Introduction}).
748 On a GNU/Linux system, a build user pool may be created like this (using
749 Bash syntax and the @code{shadow} commands):
751 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
752 @c for why `-G' is needed.
754 # groupadd --system guixbuild
755 # for i in `seq -w 1 10`;
757 useradd -g guixbuild -G guixbuild \
758 -d /var/empty -s `which nologin` \
759 -c "Guix build user $i" --system \
765 The number of build users determines how many build jobs may run in
766 parallel, as specified by the @option{--max-jobs} option
767 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
768 @command{guix system vm} and related commands, you may need to add the
769 build users to the @code{kvm} group so they can access @file{/dev/kvm},
770 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
771 (@pxref{Invoking guix system}).
773 The @code{guix-daemon} program may then be run as @code{root} with the
774 following command@footnote{If your machine uses the systemd init system,
775 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
776 file in @file{/etc/systemd/system} will ensure that
777 @command{guix-daemon} is automatically started. Similarly, if your
778 machine uses the Upstart init system, drop the
779 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
780 file in @file{/etc/init}.}:
783 # guix-daemon --build-users-group=guixbuild
788 This way, the daemon starts build processes in a chroot, under one of
789 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
790 environment contains nothing but:
792 @c Keep this list in sync with libstore/build.cc! -----------------------
795 a minimal @code{/dev} directory, created mostly independently from the
796 host @code{/dev}@footnote{``Mostly'', because while the set of files
797 that appear in the chroot's @code{/dev} is fixed, most of these files
798 can only be created if the host has them.};
801 the @code{/proc} directory; it only shows the processes of the container
802 since a separate PID name space is used;
805 @file{/etc/passwd} with an entry for the current user and an entry for
809 @file{/etc/group} with an entry for the user's group;
812 @file{/etc/hosts} with an entry that maps @code{localhost} to
816 a writable @file{/tmp} directory.
819 You can influence the directory where the daemon stores build trees
820 @i{via} the @code{TMPDIR} environment variable. However, the build tree
821 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
822 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
823 This way, the value of @code{TMPDIR} does not leak inside build
824 environments, which avoids discrepancies in cases where build processes
825 capture the name of their build tree.
828 The daemon also honors the @code{http_proxy} environment variable for
829 HTTP downloads it performs, be it for fixed-output derivations
830 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
832 If you are installing Guix as an unprivileged user, it is still possible
833 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
834 However, build processes will not be isolated from one another, and not
835 from the rest of the system. Thus, build processes may interfere with
836 each other, and may access programs, libraries, and other files
837 available on the system---making it much harder to view them as
838 @emph{pure} functions.
841 @node Daemon Offload Setup
842 @subsection Using the Offload Facility
846 When desired, the build daemon can @dfn{offload} derivation builds to
847 other machines running Guix, using the @code{offload} @dfn{build
848 hook}@footnote{This feature is available only when
849 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
851 feature is enabled, a list of user-specified build machines is read from
852 @file{/etc/guix/machines.scm}; every time a build is requested, for
853 instance via @code{guix build}, the daemon attempts to offload it to one
854 of the machines that satisfy the constraints of the derivation, in
855 particular its system type---e.g., @file{x86_64-linux}. Missing
856 prerequisites for the build are copied over SSH to the target machine,
857 which then proceeds with the build; upon success the output(s) of the
858 build are copied back to the initial machine.
860 The @file{/etc/guix/machines.scm} file typically looks like this:
864 (name "eightysix.example.org")
865 (system "x86_64-linux")
866 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
868 (speed 2.)) ;incredibly fast!
871 (name "meeps.example.org")
872 (system "mips64el-linux")
873 (host-key "ssh-rsa AAAAB3Nza@dots{}")
876 (string-append (getenv "HOME")
877 "/.ssh/identity-for-guix"))))
881 In the example above we specify a list of two build machines, one for
882 the @code{x86_64} architecture and one for the @code{mips64el}
885 In fact, this file is---not surprisingly!---a Scheme file that is
886 evaluated when the @code{offload} hook is started. Its return value
887 must be a list of @code{build-machine} objects. While this example
888 shows a fixed list of build machines, one could imagine, say, using
889 DNS-SD to return a list of potential build machines discovered in the
890 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
891 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
894 @deftp {Data Type} build-machine
895 This data type represents build machines to which the daemon may offload
896 builds. The important fields are:
901 The host name of the remote machine.
904 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
907 The user account to use when connecting to the remote machine over SSH.
908 Note that the SSH key pair must @emph{not} be passphrase-protected, to
909 allow non-interactive logins.
912 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
913 This is used to authenticate the machine when we connect to it. It is a
914 long string that looks like this:
917 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
920 If the machine is running the OpenSSH daemon, @command{sshd}, the host
921 key can be found in a file such as
922 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
924 If the machine is running the SSH daemon of GNU@tie{}lsh,
925 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
926 similar file. It can be converted to the OpenSSH format using
927 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
930 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
931 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
936 A number of optional fields may be specified:
940 @item @code{port} (default: @code{22})
941 Port number of SSH server on the machine.
943 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
944 The SSH private key file to use when connecting to the machine, in
947 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
948 @itemx @code{compression-level} (default: @code{3})
949 The SSH-level compression methods and compression level requested.
951 Note that offloading relies on SSH compression to reduce bandwidth usage
952 when transferring files to and from build machines.
954 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
955 File name of the Unix-domain socket @command{guix-daemon} is listening
958 @item @code{parallel-builds} (default: @code{1})
959 The number of builds that may run in parallel on the machine.
961 @item @code{speed} (default: @code{1.0})
962 A ``relative speed factor''. The offload scheduler will tend to prefer
963 machines with a higher speed factor.
965 @item @code{features} (default: @code{'()})
966 A list of strings denoting specific features supported by the machine.
967 An example is @code{"kvm"} for machines that have the KVM Linux modules
968 and corresponding hardware support. Derivations can request features by
969 name, and they will be scheduled on matching build machines.
974 The @code{guile} command must be in the search path on the build
975 machines. In addition, the Guix modules must be in
976 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
977 this is the case by running:
980 ssh build-machine guile -c "'(use-modules (guix config))'"
983 There is one last thing to do once @file{machines.scm} is in place. As
984 explained above, when offloading, files are transferred back and forth
985 between the machine stores. For this to work, you first need to
986 generate a key pair on each machine to allow the daemon to export signed
987 archives of files from the store (@pxref{Invoking guix archive}):
990 # guix archive --generate-key
994 Each build machine must authorize the key of the master machine so that
995 it accepts store items it receives from the master:
998 # guix archive --authorize < master-public-key.txt
1002 Likewise, the master machine must authorize the key of each build machine.
1004 All the fuss with keys is here to express pairwise mutual trust
1005 relations between the master and the build machines. Concretely, when
1006 the master receives files from a build machine (and @i{vice versa}), its
1007 build daemon can make sure they are genuine, have not been tampered
1008 with, and that they are signed by an authorized key.
1010 @cindex offload test
1011 To test whether your setup is operational, run this command on the
1018 This will attempt to connect to each of the build machines specified in
1019 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1020 available on each machine, attempt to export to the machine and import
1021 from it, and report any error in the process.
1023 If you want to test a different machine file, just specify it on the
1027 # guix offload test machines-qualif.scm
1030 Last, you can test the subset of the machines whose name matches a
1031 regular expression like this:
1034 # guix offload test machines.scm '\.gnu\.org$'
1037 @node Invoking guix-daemon
1038 @section Invoking @command{guix-daemon}
1040 The @command{guix-daemon} program implements all the functionality to
1041 access the store. This includes launching build processes, running the
1042 garbage collector, querying the availability of a build result, etc. It
1043 is normally run as @code{root} like this:
1046 # guix-daemon --build-users-group=guixbuild
1050 For details on how to set it up, @pxref{Setting Up the Daemon}.
1053 @cindex container, build environment
1054 @cindex build environment
1055 @cindex reproducible builds
1056 By default, @command{guix-daemon} launches build processes under
1057 different UIDs, taken from the build group specified with
1058 @code{--build-users-group}. In addition, each build process is run in a
1059 chroot environment that only contains the subset of the store that the
1060 build process depends on, as specified by its derivation
1061 (@pxref{Programming Interface, derivation}), plus a set of specific
1062 system directories. By default, the latter contains @file{/dev} and
1063 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1064 @dfn{container}: in addition to having its own file system tree, it has
1065 a separate mount name space, its own PID name space, network name space,
1066 etc. This helps achieve reproducible builds (@pxref{Features}).
1068 When the daemon performs a build on behalf of the user, it creates a
1069 build directory under @file{/tmp} or under the directory specified by
1070 its @code{TMPDIR} environment variable; this directory is shared with
1071 the container for the duration of the build. Be aware that using a
1072 directory other than @file{/tmp} can affect build results---for example,
1073 with a longer directory name, a build process that uses Unix-domain
1074 sockets might hit the name length limitation for @code{sun_path}, which
1075 it would otherwise not hit.
1077 The build directory is automatically deleted upon completion, unless the
1078 build failed and the client specified @option{--keep-failed}
1079 (@pxref{Invoking guix build, @option{--keep-failed}}).
1081 The following command-line options are supported:
1084 @item --build-users-group=@var{group}
1085 Take users from @var{group} to run build processes (@pxref{Setting Up
1086 the Daemon, build users}).
1088 @item --no-substitutes
1090 Do not use substitutes for build products. That is, always build things
1091 locally instead of allowing downloads of pre-built binaries
1092 (@pxref{Substitutes}).
1094 By default substitutes are used, unless the client---such as the
1095 @command{guix package} command---is explicitly invoked with
1096 @code{--no-substitutes}.
1098 When the daemon runs with @code{--no-substitutes}, clients can still
1099 explicitly enable substitution @i{via} the @code{set-build-options}
1100 remote procedure call (@pxref{The Store}).
1102 @item --substitute-urls=@var{urls}
1103 @anchor{daemon-substitute-urls}
1104 Consider @var{urls} the default whitespace-separated list of substitute
1105 source URLs. When this option is omitted,
1106 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1107 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1109 This means that substitutes may be downloaded from @var{urls}, as long
1110 as they are signed by a trusted signature (@pxref{Substitutes}).
1113 @item --no-build-hook
1114 Do not use the @dfn{build hook}.
1116 The build hook is a helper program that the daemon can start and to
1117 which it submits build requests. This mechanism is used to offload
1118 builds to other machines (@pxref{Daemon Offload Setup}).
1120 @item --cache-failures
1121 Cache build failures. By default, only successful builds are cached.
1123 When this option is used, @command{guix gc --list-failures} can be used
1124 to query the set of store items marked as failed; @command{guix gc
1125 --clear-failures} removes store items from the set of cached failures.
1126 @xref{Invoking guix gc}.
1128 @item --cores=@var{n}
1130 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1133 The default value is @code{0}, but it may be overridden by clients, such
1134 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1137 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1138 in the build process, which can then use it to exploit internal
1139 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1141 @item --max-jobs=@var{n}
1143 Allow at most @var{n} build jobs in parallel. The default value is
1144 @code{1}. Setting it to @code{0} means that no builds will be performed
1145 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1146 Setup}), or simply fail.
1148 @item --rounds=@var{N}
1149 Build each derivation @var{n} times in a row, and raise an error if
1150 consecutive build results are not bit-for-bit identical. Note that this
1151 setting can be overridden by clients such as @command{guix build}
1152 (@pxref{Invoking guix build}).
1154 When used in conjunction with @option{--keep-failed}, the differing
1155 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1156 This makes it easy to look for differences between the two results.
1159 Produce debugging output.
1161 This is useful to debug daemon start-up issues, but then it may be
1162 overridden by clients, for example the @code{--verbosity} option of
1163 @command{guix build} (@pxref{Invoking guix build}).
1165 @item --chroot-directory=@var{dir}
1166 Add @var{dir} to the build chroot.
1168 Doing this may change the result of build processes---for instance if
1169 they use optional dependencies found in @var{dir} when it is available,
1170 and not otherwise. For that reason, it is not recommended to do so.
1171 Instead, make sure that each derivation declares all the inputs that it
1174 @item --disable-chroot
1175 Disable chroot builds.
1177 Using this option is not recommended since, again, it would allow build
1178 processes to gain access to undeclared dependencies. It is necessary,
1179 though, when @command{guix-daemon} is running under an unprivileged user
1182 @item --disable-log-compression
1183 Disable compression of the build logs.
1185 Unless @code{--lose-logs} is used, all the build logs are kept in the
1186 @var{localstatedir}. To save space, the daemon automatically compresses
1187 them with bzip2 by default. This option disables that.
1189 @item --disable-deduplication
1190 @cindex deduplication
1191 Disable automatic file ``deduplication'' in the store.
1193 By default, files added to the store are automatically ``deduplicated'':
1194 if a newly added file is identical to another one found in the store,
1195 the daemon makes the new file a hard link to the other file. This can
1196 noticeably reduce disk usage, at the expense of slightly increased
1197 input/output load at the end of a build process. This option disables
1200 @item --gc-keep-outputs[=yes|no]
1201 Tell whether the garbage collector (GC) must keep outputs of live
1204 When set to ``yes'', the GC will keep the outputs of any live derivation
1205 available in the store---the @code{.drv} files. The default is ``no'',
1206 meaning that derivation outputs are kept only if they are GC roots.
1208 @item --gc-keep-derivations[=yes|no]
1209 Tell whether the garbage collector (GC) must keep derivations
1210 corresponding to live outputs.
1212 When set to ``yes'', as is the case by default, the GC keeps
1213 derivations---i.e., @code{.drv} files---as long as at least one of their
1214 outputs is live. This allows users to keep track of the origins of
1215 items in their store. Setting it to ``no'' saves a bit of disk space.
1217 Note that when both @code{--gc-keep-derivations} and
1218 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1219 prerequisites (the sources, compiler, libraries, and other build-time
1220 tools) of live objects in the store, regardless of whether these
1221 prerequisites are live. This is convenient for developers since it
1222 saves rebuilds or downloads.
1224 @item --impersonate-linux-2.6
1225 On Linux-based systems, impersonate Linux 2.6. This means that the
1226 kernel's @code{uname} system call will report 2.6 as the release number.
1228 This might be helpful to build programs that (usually wrongfully) depend
1229 on the kernel version number.
1232 Do not keep build logs. By default they are kept under
1233 @code{@var{localstatedir}/guix/log}.
1235 @item --system=@var{system}
1236 Assume @var{system} as the current system type. By default it is the
1237 architecture/kernel pair found at configure time, such as
1238 @code{x86_64-linux}.
1240 @item --listen=@var{socket}
1241 Listen for connections on @var{socket}, the file name of a Unix-domain
1242 socket. The default socket is
1243 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1244 useful in exceptional circumstances, such as if you need to run several
1245 daemons on the same machine.
1249 @node Application Setup
1250 @section Application Setup
1252 @cindex foreign distro
1253 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1254 so-called @dfn{foreign distro}---a few additional steps are needed to
1255 get everything in place. Here are some of them.
1259 @anchor{locales-and-locpath}
1260 @cindex locales, when not on GuixSD
1262 @vindex GUIX_LOCPATH
1263 Packages installed @i{via} Guix will not use the locale data of the
1264 host system. Instead, you must first install one of the locale packages
1265 available with Guix and then define the @code{GUIX_LOCPATH} environment
1269 $ guix package -i glibc-locales
1270 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1273 Note that the @code{glibc-locales} package contains data for all the
1274 locales supported by the GNU@tie{}libc and weighs in at around
1275 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1276 limited to a few UTF-8 locales.
1278 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1279 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1280 Manual}). There are two important differences though:
1284 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1285 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1286 to make sure the programs of the foreign distro will not end up loading
1287 incompatible locale data.
1290 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1291 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1292 should your Guix profile contain a mixture of programs linked against
1293 different libc version, each libc version will only try to load locale
1294 data in the right format.
1297 This is important because the locale data format used by different libc
1298 versions may be incompatible.
1300 @subsection Name Service Switch
1302 @cindex name service switch, glibc
1303 @cindex NSS (name service switch), glibc
1304 @cindex nscd (name service caching daemon)
1305 @cindex name service caching daemon (nscd)
1306 When using Guix on a foreign distro, we @emph{strongly recommend} that
1307 the system run the GNU C library's @dfn{name service cache daemon},
1308 @command{nscd}, which should be listening on the
1309 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1310 installed with Guix may fail to look up host names or user accounts, or
1311 may even crash. The next paragraphs explain why.
1313 @cindex @file{nsswitch.conf}
1314 The GNU C library implements a @dfn{name service switch} (NSS), which is
1315 an extensible mechanism for ``name lookups'' in general: host name
1316 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1317 The GNU C Library Reference Manual}).
1319 @cindex Network information service (NIS)
1320 @cindex NIS (Network information service)
1321 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1322 lookup implementations: for example, the @code{nss-mdns} plugin allow
1323 resolution of @code{.local} host names, the @code{nis} plugin allows
1324 user account lookup using the Network information service (NIS), and so
1325 on. These extra ``lookup services'' are configured system-wide in
1326 @file{/etc/nsswitch.conf}, and all the programs running on the system
1327 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1330 When they perform a name lookup---for instance by calling the
1331 @code{getaddrinfo} function in C---applications first try to connect to
1332 the nscd; on success, nscd performs name lookups on their behalf. If
1333 the nscd is not running, then they perform the name lookup by
1334 themselves, by loading the name lookup services into their own address
1335 space and running it. These name lookup services---the
1336 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1337 the host system's C library, rather than from the C library the
1338 application is linked against (the C library coming from Guix).
1340 And this is where the problem is: if your application is linked against
1341 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1342 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1343 likely crash or have its name lookups fail unexpectedly.
1345 Running @command{nscd} on the system, among other advantages, eliminates
1346 this binary incompatibility problem because those @code{libnss_*.so}
1347 files are loaded in the @command{nscd} process, not in applications
1350 @subsection X11 Fonts
1353 The majority of graphical applications use Fontconfig to locate and
1354 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1355 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1356 by default. Thus, to allow graphical applications installed with Guix
1357 to display fonts, you have to install fonts with Guix as well.
1358 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1359 @code{font-gnu-freefont-ttf}.
1361 To display text written in Chinese languages, Japanese, or Korean in
1362 graphical applications, consider installing
1363 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1364 has multiple outputs, one per language family (@pxref{Packages with
1365 Multiple Outputs}). For instance, the following command installs fonts
1366 for Chinese languages:
1369 guix package -i font-adobe-source-han-sans:cn
1372 @cindex @code{xterm}
1373 Older programs such as @command{xterm} do not use Fontconfig and instead
1374 rely on server-side font rendering. Such programs require to specify a
1375 full name of a font using XLFD (X Logical Font Description), like this:
1378 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1381 To be able to use such full names for the TrueType fonts installed in
1382 your Guix profile, you need to extend the font path of the X server:
1385 xset +fp ~/.guix-profile/share/fonts/truetype
1388 @cindex @code{xlsfonts}
1389 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1390 to make sure your TrueType fonts are listed there.
1392 @subsection X.509 Certificates
1394 @cindex @code{nss-certs}
1395 The @code{nss-certs} package provides X.509 certificates, which allow
1396 programs to authenticate Web servers accessed over HTTPS.
1398 When using Guix on a foreign distro, you can install this package and
1399 define the relevant environment variables so that packages know where to
1400 look for certificates. @xref{X.509 Certificates}, for detailed
1403 @subsection Emacs Packages
1405 @cindex @code{emacs}
1406 When you install Emacs packages with Guix, the elisp files may be placed
1407 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1409 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1410 directory exists because potentially there may exist thousands of Emacs
1411 packages and storing all their files in a single directory may be not
1412 reliable (because of name conflicts). So we think using a separate
1413 directory for each package is a good idea. It is very similar to how
1414 the Emacs package system organizes the file structure (@pxref{Package
1415 Files,,, emacs, The GNU Emacs Manual}).
1417 By default, Emacs (installed with Guix) ``knows'' where these packages
1418 are placed, so you do not need to perform any configuration. If, for
1419 some reason, you want to avoid auto-loading Emacs packages installed
1420 with Guix, you can do so by running Emacs with @code{--no-site-file}
1421 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1425 @c *********************************************************************
1426 @node Package Management
1427 @chapter Package Management
1430 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1431 remove software packages, without having to know about their build
1432 procedures or dependencies. Guix also goes beyond this obvious set of
1435 This chapter describes the main features of Guix, as well as the
1436 package management tools it provides. Along with the command-line
1437 interface described below (@pxref{Invoking guix package, @code{guix
1438 package}}), you may also use Emacs Interface (@pxref{Top,,,
1439 emacs-guix, The Emacs-Guix Reference Manual}), after installing
1440 @code{emacs-guix} package (run @kbd{M-x guix-help} command to start
1444 guix package -i emacs-guix
1448 * Features:: How Guix will make your life brighter.
1449 * Invoking guix package:: Package installation, removal, etc.
1450 * Substitutes:: Downloading pre-built binaries.
1451 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1452 * Invoking guix gc:: Running the garbage collector.
1453 * Invoking guix pull:: Fetching the latest Guix and distribution.
1454 * Invoking guix pack:: Creating software bundles.
1455 * Invoking guix archive:: Exporting and importing store files.
1461 When using Guix, each package ends up in the @dfn{package store}, in its
1462 own directory---something that resembles
1463 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1465 Instead of referring to these directories, users have their own
1466 @dfn{profile}, which points to the packages that they actually want to
1467 use. These profiles are stored within each user's home directory, at
1468 @code{$HOME/.guix-profile}.
1470 For example, @code{alice} installs GCC 4.7.2. As a result,
1471 @file{/home/alice/.guix-profile/bin/gcc} points to
1472 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1473 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1474 simply continues to point to
1475 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1476 coexist on the same system without any interference.
1478 The @command{guix package} command is the central tool to manage
1479 packages (@pxref{Invoking guix package}). It operates on the per-user
1480 profiles, and can be used @emph{with normal user privileges}.
1482 @cindex transactions
1483 The command provides the obvious install, remove, and upgrade
1484 operations. Each invocation is actually a @emph{transaction}: either
1485 the specified operation succeeds, or nothing happens. Thus, if the
1486 @command{guix package} process is terminated during the transaction,
1487 or if a power outage occurs during the transaction, then the user's
1488 profile remains in its previous state, and remains usable.
1490 In addition, any package transaction may be @emph{rolled back}. So, if,
1491 for example, an upgrade installs a new version of a package that turns
1492 out to have a serious bug, users may roll back to the previous instance
1493 of their profile, which was known to work well. Similarly, the global
1494 system configuration on GuixSD is subject to
1495 transactional upgrades and roll-back
1496 (@pxref{Using the Configuration System}).
1498 All packages in the package store may be @emph{garbage-collected}.
1499 Guix can determine which packages are still referenced by user
1500 profiles, and remove those that are provably no longer referenced
1501 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1502 generations of their profile so that the packages they refer to can be
1505 @cindex reproducibility
1506 @cindex reproducible builds
1507 Finally, Guix takes a @dfn{purely functional} approach to package
1508 management, as described in the introduction (@pxref{Introduction}).
1509 Each @file{/gnu/store} package directory name contains a hash of all the
1510 inputs that were used to build that package---compiler, libraries, build
1511 scripts, etc. This direct correspondence allows users to make sure a
1512 given package installation matches the current state of their
1513 distribution. It also helps maximize @dfn{build reproducibility}:
1514 thanks to the isolated build environments that are used, a given build
1515 is likely to yield bit-identical files when performed on different
1516 machines (@pxref{Invoking guix-daemon, container}).
1519 This foundation allows Guix to support @dfn{transparent binary/source
1520 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1521 available from an external source---a @dfn{substitute}, Guix just
1522 downloads it and unpacks it;
1523 otherwise, it builds the package from source, locally
1524 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1525 reproducible, users do not have to trust servers that provide
1526 substitutes: they can force a local build and @emph{challenge} providers
1527 (@pxref{Invoking guix challenge}).
1529 Control over the build environment is a feature that is also useful for
1530 developers. The @command{guix environment} command allows developers of
1531 a package to quickly set up the right development environment for their
1532 package, without having to manually install the dependencies of the
1533 package into their profile (@pxref{Invoking guix environment}).
1535 @node Invoking guix package
1536 @section Invoking @command{guix package}
1538 @cindex installing packages
1539 @cindex removing packages
1540 @cindex package installation
1541 @cindex package removal
1542 The @command{guix package} command is the tool that allows users to
1543 install, upgrade, and remove packages, as well as rolling back to
1544 previous configurations. It operates only on the user's own profile,
1545 and works with normal user privileges (@pxref{Features}). Its syntax
1549 guix package @var{options}
1551 @cindex transactions
1552 Primarily, @var{options} specifies the operations to be performed during
1553 the transaction. Upon completion, a new profile is created, but
1554 previous @dfn{generations} of the profile remain available, should the user
1557 For example, to remove @code{lua} and install @code{guile} and
1558 @code{guile-cairo} in a single transaction:
1561 guix package -r lua -i guile guile-cairo
1564 @command{guix package} also supports a @dfn{declarative approach}
1565 whereby the user specifies the exact set of packages to be available and
1566 passes it @i{via} the @option{--manifest} option
1567 (@pxref{profile-manifest, @option{--manifest}}).
1570 For each user, a symlink to the user's default profile is automatically
1571 created in @file{$HOME/.guix-profile}. This symlink always points to the
1572 current generation of the user's default profile. Thus, users can add
1573 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1574 variable, and so on.
1575 @cindex search paths
1576 If you are not using the Guix System Distribution, consider adding the
1577 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1578 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1579 shells get all the right environment variable definitions:
1582 GUIX_PROFILE="$HOME/.guix-profile" \
1583 source "$HOME/.guix-profile/etc/profile"
1586 In a multi-user setup, user profiles are stored in a place registered as
1587 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1588 to (@pxref{Invoking guix gc}). That directory is normally
1589 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1590 @var{localstatedir} is the value passed to @code{configure} as
1591 @code{--localstatedir}, and @var{user} is the user name. The
1592 @file{per-user} directory is created when @command{guix-daemon} is
1593 started, and the @var{user} sub-directory is created by @command{guix
1596 The @var{options} can be among the following:
1600 @item --install=@var{package} @dots{}
1601 @itemx -i @var{package} @dots{}
1602 Install the specified @var{package}s.
1604 Each @var{package} may specify either a simple package name, such as
1605 @code{guile}, or a package name followed by an at-sign and version number,
1606 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1607 case, the newest version prefixed by @code{1.8} is selected.)
1609 If no version number is specified, the
1610 newest available version will be selected. In addition, @var{package}
1611 may contain a colon, followed by the name of one of the outputs of the
1612 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1613 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1614 name (and optionally version) are searched for among the GNU
1615 distribution modules (@pxref{Package Modules}).
1617 @cindex propagated inputs
1618 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1619 that automatically get installed along with the required package
1620 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1621 @code{package} objects}, for information about propagated inputs in
1622 package definitions).
1624 @anchor{package-cmd-propagated-inputs}
1625 An example is the GNU MPC library: its C header files refer to those of
1626 the GNU MPFR library, which in turn refer to those of the GMP library.
1627 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1628 in the profile; removing MPC also removes MPFR and GMP---unless they had
1629 also been explicitly installed by the user.
1631 Besides, packages sometimes rely on the definition of environment
1632 variables for their search paths (see explanation of
1633 @code{--search-paths} below). Any missing or possibly incorrect
1634 environment variable definitions are reported here.
1636 @item --install-from-expression=@var{exp}
1638 Install the package @var{exp} evaluates to.
1640 @var{exp} must be a Scheme expression that evaluates to a
1641 @code{<package>} object. This option is notably useful to disambiguate
1642 between same-named variants of a package, with expressions such as
1643 @code{(@@ (gnu packages base) guile-final)}.
1645 Note that this option installs the first output of the specified
1646 package, which may be insufficient when needing a specific output of a
1647 multiple-output package.
1649 @item --install-from-file=@var{file}
1650 @itemx -f @var{file}
1651 Install the package that the code within @var{file} evaluates to.
1653 As an example, @var{file} might contain a definition like this
1654 (@pxref{Defining Packages}):
1657 @verbatiminclude package-hello.scm
1660 Developers may find it useful to include such a @file{guix.scm} file
1661 in the root of their project source tree that can be used to test
1662 development snapshots and create reproducible development environments
1663 (@pxref{Invoking guix environment}).
1665 @item --remove=@var{package} @dots{}
1666 @itemx -r @var{package} @dots{}
1667 Remove the specified @var{package}s.
1669 As for @code{--install}, each @var{package} may specify a version number
1670 and/or output name in addition to the package name. For instance,
1671 @code{-r glibc:debug} would remove the @code{debug} output of
1674 @item --upgrade[=@var{regexp} @dots{}]
1675 @itemx -u [@var{regexp} @dots{}]
1676 @cindex upgrading packages
1677 Upgrade all the installed packages. If one or more @var{regexp}s are
1678 specified, upgrade only installed packages whose name matches a
1679 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1681 Note that this upgrades package to the latest version of packages found
1682 in the distribution currently installed. To update your distribution,
1683 you should regularly run @command{guix pull} (@pxref{Invoking guix
1686 @item --do-not-upgrade[=@var{regexp} @dots{}]
1687 When used together with the @code{--upgrade} option, do @emph{not}
1688 upgrade any packages whose name matches a @var{regexp}. For example, to
1689 upgrade all packages in the current profile except those containing the
1690 substring ``emacs'':
1693 $ guix package --upgrade . --do-not-upgrade emacs
1696 @item @anchor{profile-manifest}--manifest=@var{file}
1697 @itemx -m @var{file}
1698 @cindex profile declaration
1699 @cindex profile manifest
1700 Create a new generation of the profile from the manifest object
1701 returned by the Scheme code in @var{file}.
1703 This allows you to @emph{declare} the profile's contents rather than
1704 constructing it through a sequence of @code{--install} and similar
1705 commands. The advantage is that @var{file} can be put under version
1706 control, copied to different machines to reproduce the same profile, and
1709 @c FIXME: Add reference to (guix profile) documentation when available.
1710 @var{file} must return a @dfn{manifest} object, which is roughly a list
1713 @findex packages->manifest
1715 (use-package-modules guile emacs)
1720 ;; Use a specific package output.
1721 (list guile-2.0 "debug")))
1724 @findex specification->package+output
1725 In this example we have to know which modules define the @code{emacs}
1726 and @code{guile-2.0} variables to provide the right
1727 @code{use-package-modules} line, which can be cumbersome. We can
1728 instead provide regular package specifications and let
1729 @code{specification->package-output} look up the corresponding package
1734 (map (compose list specification->package+output)
1735 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1739 @cindex rolling back
1740 @cindex undoing transactions
1741 @cindex transactions, undoing
1742 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1743 the last transaction.
1745 When combined with options such as @code{--install}, roll back occurs
1746 before any other actions.
1748 When rolling back from the first generation that actually contains
1749 installed packages, the profile is made to point to the @dfn{zeroth
1750 generation}, which contains no files apart from its own metadata.
1752 After having rolled back, installing, removing, or upgrading packages
1753 overwrites previous future generations. Thus, the history of the
1754 generations in a profile is always linear.
1756 @item --switch-generation=@var{pattern}
1757 @itemx -S @var{pattern}
1759 Switch to a particular generation defined by @var{pattern}.
1761 @var{pattern} may be either a generation number or a number prefixed
1762 with ``+'' or ``-''. The latter means: move forward/backward by a
1763 specified number of generations. For example, if you want to return to
1764 the latest generation after @code{--roll-back}, use
1765 @code{--switch-generation=+1}.
1767 The difference between @code{--roll-back} and
1768 @code{--switch-generation=-1} is that @code{--switch-generation} will
1769 not make a zeroth generation, so if a specified generation does not
1770 exist, the current generation will not be changed.
1772 @item --search-paths[=@var{kind}]
1773 @cindex search paths
1774 Report environment variable definitions, in Bash syntax, that may be
1775 needed in order to use the set of installed packages. These environment
1776 variables are used to specify @dfn{search paths} for files used by some
1777 of the installed packages.
1779 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1780 environment variables to be defined so it can look for headers and
1781 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1782 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1783 library are installed in the profile, then @code{--search-paths} will
1784 suggest setting these variables to @code{@var{profile}/include} and
1785 @code{@var{profile}/lib}, respectively.
1787 The typical use case is to define these environment variables in the
1791 $ eval `guix package --search-paths`
1794 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1795 meaning that the returned environment variable definitions will either
1796 be exact settings, or prefixes or suffixes of the current value of these
1797 variables. When omitted, @var{kind} defaults to @code{exact}.
1799 This option can also be used to compute the @emph{combined} search paths
1800 of several profiles. Consider this example:
1803 $ guix package -p foo -i guile
1804 $ guix package -p bar -i guile-json
1805 $ guix package -p foo -p bar --search-paths
1808 The last command above reports about the @code{GUILE_LOAD_PATH}
1809 variable, even though, taken individually, neither @file{foo} nor
1810 @file{bar} would lead to that recommendation.
1813 @item --profile=@var{profile}
1814 @itemx -p @var{profile}
1815 Use @var{profile} instead of the user's default profile.
1818 Produce verbose output. In particular, emit the build log of the
1819 environment on the standard error port.
1822 Use the bootstrap Guile to build the profile. This option is only
1823 useful to distribution developers.
1827 In addition to these actions, @command{guix package} supports the
1828 following options to query the current state of a profile, or the
1829 availability of packages:
1833 @item --search=@var{regexp}
1834 @itemx -s @var{regexp}
1835 @cindex searching for packages
1836 List the available packages whose name, synopsis, or description matches
1837 @var{regexp}. Print all the metadata of matching packages in
1838 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1839 GNU recutils manual}).
1841 This allows specific fields to be extracted using the @command{recsel}
1842 command, for instance:
1845 $ guix package -s malloc | recsel -p name,version
1853 Similarly, to show the name of all the packages available under the
1854 terms of the GNU@tie{}LGPL version 3:
1857 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1864 It is also possible to refine search results using several @code{-s}
1865 flags. For example, the following command returns a list of board
1869 $ guix package -s '\<board\>' -s game | recsel -p name
1874 If we were to omit @code{-s game}, we would also get software packages
1875 that deal with printed circuit boards; removing the angle brackets
1876 around @code{board} would further add packages that have to do with
1879 And now for a more elaborate example. The following command searches
1880 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1881 libraries, and prints the name and synopsis of the matching packages:
1884 $ guix package -s crypto -s library | \
1885 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1889 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1890 information on @dfn{selection expressions} for @code{recsel -e}.
1892 @item --show=@var{package}
1893 Show details about @var{package}, taken from the list of available packages, in
1894 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1898 $ guix package --show=python | recsel -p name,version
1906 You may also specify the full name of a package to only get details about a
1907 specific version of it:
1909 $ guix package --show=python@@3.4 | recsel -p name,version
1916 @item --list-installed[=@var{regexp}]
1917 @itemx -I [@var{regexp}]
1918 List the currently installed packages in the specified profile, with the
1919 most recently installed packages shown last. When @var{regexp} is
1920 specified, list only installed packages whose name matches @var{regexp}.
1922 For each installed package, print the following items, separated by
1923 tabs: the package name, its version string, the part of the package that
1924 is installed (for instance, @code{out} for the default output,
1925 @code{include} for its headers, etc.), and the path of this package in
1928 @item --list-available[=@var{regexp}]
1929 @itemx -A [@var{regexp}]
1930 List packages currently available in the distribution for this system
1931 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1932 installed packages whose name matches @var{regexp}.
1934 For each package, print the following items separated by tabs: its name,
1935 its version string, the parts of the package (@pxref{Packages with
1936 Multiple Outputs}), and the source location of its definition.
1938 @item --list-generations[=@var{pattern}]
1939 @itemx -l [@var{pattern}]
1941 Return a list of generations along with their creation dates; for each
1942 generation, show the installed packages, with the most recently
1943 installed packages shown last. Note that the zeroth generation is never
1946 For each installed package, print the following items, separated by
1947 tabs: the name of a package, its version string, the part of the package
1948 that is installed (@pxref{Packages with Multiple Outputs}), and the
1949 location of this package in the store.
1951 When @var{pattern} is used, the command returns only matching
1952 generations. Valid patterns include:
1955 @item @emph{Integers and comma-separated integers}. Both patterns denote
1956 generation numbers. For instance, @code{--list-generations=1} returns
1959 And @code{--list-generations=1,8,2} outputs three generations in the
1960 specified order. Neither spaces nor trailing commas are allowed.
1962 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1963 specified generations and everything in between. Note that the start of
1964 a range must be smaller than its end.
1966 It is also possible to omit the endpoint. For example,
1967 @code{--list-generations=2..}, returns all generations starting from the
1970 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1971 or months by passing an integer along with the first letter of the
1972 duration. For example, @code{--list-generations=20d} lists generations
1973 that are up to 20 days old.
1976 @item --delete-generations[=@var{pattern}]
1977 @itemx -d [@var{pattern}]
1978 When @var{pattern} is omitted, delete all generations except the current
1981 This command accepts the same patterns as @option{--list-generations}.
1982 When @var{pattern} is specified, delete the matching generations. When
1983 @var{pattern} specifies a duration, generations @emph{older} than the
1984 specified duration match. For instance, @code{--delete-generations=1m}
1985 deletes generations that are more than one month old.
1987 If the current generation matches, it is @emph{not} deleted. Also, the
1988 zeroth generation is never deleted.
1990 Note that deleting generations prevents rolling back to them.
1991 Consequently, this command must be used with care.
1995 Finally, since @command{guix package} may actually start build
1996 processes, it supports all the common build options (@pxref{Common Build
1997 Options}). It also supports package transformation options, such as
1998 @option{--with-source} (@pxref{Package Transformation Options}).
1999 However, note that package transformations are lost when upgrading; to
2000 preserve transformations across upgrades, you should define your own
2001 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
2002 (@pxref{Defining Packages}).
2006 @section Substitutes
2009 @cindex pre-built binaries
2010 Guix supports transparent source/binary deployment, which means that it
2011 can either build things locally, or download pre-built items from a
2012 server. We call these pre-built items @dfn{substitutes}---they are
2013 substitutes for local build results. In many cases, downloading a
2014 substitute is much faster than building things locally.
2016 Substitutes can be anything resulting from a derivation build
2017 (@pxref{Derivations}). Of course, in the common case, they are
2018 pre-built package binaries, but source tarballs, for instance, which
2019 also result from derivation builds, can be available as substitutes.
2021 The @code{hydra.gnu.org} server is a front-end to a build farm that
2022 builds packages from the GNU distribution continuously for some
2023 architectures, and makes them available as substitutes. This is the
2024 default source of substitutes; it can be overridden by passing the
2025 @option{--substitute-urls} option either to @command{guix-daemon}
2026 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2027 or to client tools such as @command{guix package}
2028 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2031 Substitute URLs can be either HTTP or HTTPS.
2032 HTTPS is recommended because communications are encrypted; conversely,
2033 using HTTP makes all communications visible to an eavesdropper, who
2034 could use the information gathered to determine, for instance, whether
2035 your system has unpatched security vulnerabilities.
2038 @cindex digital signatures
2039 @cindex substitutes, authorization thereof
2040 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2042 must add its public key to the access control list (ACL) of archive
2043 imports, using the @command{guix archive} command (@pxref{Invoking guix
2044 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2045 be compromised and to serve genuine substitutes.
2047 This public key is installed along with Guix, in
2048 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2049 the installation prefix of Guix. If you installed Guix from source,
2050 make sure you checked the GPG signature of
2051 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2052 Then, you can run something like this:
2055 # guix archive --authorize < hydra.gnu.org.pub
2058 Once this is in place, the output of a command like @code{guix build}
2059 should change from something like:
2062 $ guix build emacs --dry-run
2063 The following derivations would be built:
2064 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2065 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2066 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2067 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2075 $ guix build emacs --dry-run
2076 The following files would be downloaded:
2077 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2078 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2079 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2080 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2085 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2086 will be downloaded, when possible, for future builds.
2088 Guix ignores substitutes that are not signed, or that are not signed by
2089 one of the keys listed in the ACL. It also detects and raises an error
2090 when attempting to use a substitute that has been tampered with.
2093 Substitutes are downloaded over HTTP or HTTPS.
2094 The @code{http_proxy} environment
2095 variable can be set in the environment of @command{guix-daemon} and is
2096 honored for downloads of substitutes. Note that the value of
2097 @code{http_proxy} in the environment where @command{guix build},
2098 @command{guix package}, and other client commands are run has
2099 @emph{absolutely no effect}.
2101 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2102 (in other words, the server is not authenticated), contrary to what
2103 HTTPS clients such as Web browsers usually do. This is because Guix
2104 authenticates substitute information itself, as explained above, which
2105 is what we care about (whereas X.509 certificates are about
2106 authenticating bindings between domain names and public keys.)
2108 The substitute mechanism can be disabled globally by running
2109 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2110 guix-daemon}). It can also be disabled temporarily by passing the
2111 @code{--no-substitutes} option to @command{guix package}, @command{guix
2112 build}, and other command-line tools.
2115 @unnumberedsubsec On Trusting Binaries
2117 Today, each individual's control over their own computing is at the
2118 mercy of institutions, corporations, and groups with enough power and
2119 determination to subvert the computing infrastructure and exploit its
2120 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2121 convenient, we encourage users to also build on their own, or even run
2122 their own build farm, such that @code{hydra.gnu.org} is less of an
2123 interesting target. One way to help is by publishing the software you
2124 build using @command{guix publish} so that others have one more choice
2125 of server to download substitutes from (@pxref{Invoking guix publish}).
2127 Guix has the foundations to maximize build reproducibility
2128 (@pxref{Features}). In most cases, independent builds of a given
2129 package or derivation should yield bit-identical results. Thus, through
2130 a diverse set of independent package builds, we can strengthen the
2131 integrity of our systems. The @command{guix challenge} command aims to
2132 help users assess substitute servers, and to assist developers in
2133 finding out about non-deterministic package builds (@pxref{Invoking guix
2134 challenge}). Similarly, the @option{--check} option of @command{guix
2135 build} allows users to check whether previously-installed substitutes
2136 are genuine by rebuilding them locally (@pxref{build-check,
2137 @command{guix build --check}}).
2139 In the future, we want Guix to have support to publish and retrieve
2140 binaries to/from other users, in a peer-to-peer fashion. If you would
2141 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2144 @node Packages with Multiple Outputs
2145 @section Packages with Multiple Outputs
2147 @cindex multiple-output packages
2148 @cindex package outputs
2151 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2152 source package leads to exactly one directory in the store. When running
2153 @command{guix package -i glibc}, one installs the default output of the
2154 GNU libc package; the default output is called @code{out}, but its name
2155 can be omitted as shown in this command. In this particular case, the
2156 default output of @code{glibc} contains all the C header files, shared
2157 libraries, static libraries, Info documentation, and other supporting
2160 Sometimes it is more appropriate to separate the various types of files
2161 produced from a single source package into separate outputs. For
2162 instance, the GLib C library (used by GTK+ and related packages)
2163 installs more than 20 MiB of reference documentation as HTML pages.
2164 To save space for users who do not need it, the documentation goes to a
2165 separate output, called @code{doc}. To install the main GLib output,
2166 which contains everything but the documentation, one would run:
2169 guix package -i glib
2172 @cindex documentation
2173 The command to install its documentation is:
2176 guix package -i glib:doc
2179 Some packages install programs with different ``dependency footprints''.
2180 For instance, the WordNet package installs both command-line tools and
2181 graphical user interfaces (GUIs). The former depend solely on the C
2182 library, whereas the latter depend on Tcl/Tk and the underlying X
2183 libraries. In this case, we leave the command-line tools in the default
2184 output, whereas the GUIs are in a separate output. This allows users
2185 who do not need the GUIs to save space. The @command{guix size} command
2186 can help find out about such situations (@pxref{Invoking guix size}).
2187 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2189 There are several such multiple-output packages in the GNU distribution.
2190 Other conventional output names include @code{lib} for libraries and
2191 possibly header files, @code{bin} for stand-alone programs, and
2192 @code{debug} for debugging information (@pxref{Installing Debugging
2193 Files}). The outputs of a packages are listed in the third column of
2194 the output of @command{guix package --list-available} (@pxref{Invoking
2198 @node Invoking guix gc
2199 @section Invoking @command{guix gc}
2201 @cindex garbage collector
2203 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2204 The @command{guix gc} command allows users to explicitly run the garbage
2205 collector to reclaim space from the @file{/gnu/store} directory. It is
2206 the @emph{only} way to remove files from @file{/gnu/store}---removing
2207 files or directories manually may break it beyond repair!
2209 The garbage collector has a set of known @dfn{roots}: any file under
2210 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2211 cannot be deleted; any other file is considered @dfn{dead} and may be
2212 deleted. The set of garbage collector roots includes default user
2213 profiles, and may be augmented with @command{guix build --root}, for
2214 example (@pxref{Invoking guix build}).
2216 Prior to running @code{guix gc --collect-garbage} to make space, it is
2217 often useful to remove old generations from user profiles; that way, old
2218 package builds referenced by those generations can be reclaimed. This
2219 is achieved by running @code{guix package --delete-generations}
2220 (@pxref{Invoking guix package}).
2222 The @command{guix gc} command has three modes of operation: it can be
2223 used to garbage-collect any dead files (the default), to delete specific
2224 files (the @code{--delete} option), to print garbage-collector
2225 information, or for more advanced queries. The garbage collection
2226 options are as follows:
2229 @item --collect-garbage[=@var{min}]
2230 @itemx -C [@var{min}]
2231 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2232 sub-directories. This is the default operation when no option is
2235 When @var{min} is given, stop once @var{min} bytes have been collected.
2236 @var{min} may be a number of bytes, or it may include a unit as a
2237 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2238 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2240 When @var{min} is omitted, collect all the garbage.
2242 @item --free-space=@var{free}
2243 @itemx -F @var{free}
2244 Collect garbage until @var{free} space is available under
2245 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2246 as @code{500MiB}, as described above.
2248 When @var{free} or more is already available in @file{/gnu/store}, do
2249 nothing and exit immediately.
2253 Attempt to delete all the store files and directories specified as
2254 arguments. This fails if some of the files are not in the store, or if
2255 they are still live.
2257 @item --list-failures
2258 List store items corresponding to cached build failures.
2260 This prints nothing unless the daemon was started with
2261 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2262 @option{--cache-failures}}).
2264 @item --clear-failures
2265 Remove the specified store items from the failed-build cache.
2267 Again, this option only makes sense when the daemon is started with
2268 @option{--cache-failures}. Otherwise, it does nothing.
2271 Show the list of dead files and directories still present in the
2272 store---i.e., files and directories no longer reachable from any root.
2275 Show the list of live store files and directories.
2279 In addition, the references among existing store files can be queried:
2285 @cindex package dependencies
2286 List the references (respectively, the referrers) of store files given
2292 List the requisites of the store files passed as arguments. Requisites
2293 include the store files themselves, their references, and the references
2294 of these, recursively. In other words, the returned list is the
2295 @dfn{transitive closure} of the store files.
2297 @xref{Invoking guix size}, for a tool to profile the size of the closure
2298 of an element. @xref{Invoking guix graph}, for a tool to visualize
2299 the graph of references.
2303 Lastly, the following options allow you to check the integrity of the
2304 store and to control disk usage.
2308 @item --verify[=@var{options}]
2309 @cindex integrity, of the store
2310 @cindex integrity checking
2311 Verify the integrity of the store.
2313 By default, make sure that all the store items marked as valid in the
2314 database of the daemon actually exist in @file{/gnu/store}.
2316 When provided, @var{options} must be a comma-separated list containing one
2317 or more of @code{contents} and @code{repair}.
2319 When passing @option{--verify=contents}, the daemon computes the
2320 content hash of each store item and compares it against its hash in the
2321 database. Hash mismatches are reported as data corruptions. Because it
2322 traverses @emph{all the files in the store}, this command can take a
2323 long time, especially on systems with a slow disk drive.
2325 @cindex repairing the store
2326 @cindex corruption, recovering from
2327 Using @option{--verify=repair} or @option{--verify=contents,repair}
2328 causes the daemon to try to repair corrupt store items by fetching
2329 substitutes for them (@pxref{Substitutes}). Because repairing is not
2330 atomic, and thus potentially dangerous, it is available only to the
2331 system administrator. A lightweight alternative, when you know exactly
2332 which items in the store are corrupt, is @command{guix build --repair}
2333 (@pxref{Invoking guix build}).
2336 @cindex deduplication
2337 Optimize the store by hard-linking identical files---this is
2338 @dfn{deduplication}.
2340 The daemon performs deduplication after each successful build or archive
2341 import, unless it was started with @code{--disable-deduplication}
2342 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2343 this option is primarily useful when the daemon was running with
2344 @code{--disable-deduplication}.
2348 @node Invoking guix pull
2349 @section Invoking @command{guix pull}
2351 @cindex upgrading Guix
2352 @cindex updating Guix
2353 @cindex @command{guix pull}
2355 Packages are installed or upgraded to the latest version available in
2356 the distribution currently available on your local machine. To update
2357 that distribution, along with the Guix tools, you must run @command{guix
2358 pull}: the command downloads the latest Guix source code and package
2359 descriptions, and deploys it.
2361 On completion, @command{guix package} will use packages and package
2362 versions from this just-retrieved copy of Guix. Not only that, but all
2363 the Guix commands and Scheme modules will also be taken from that latest
2364 version. New @command{guix} sub-commands added by the update also
2367 Any user can update their Guix copy using @command{guix pull}, and the
2368 effect is limited to the user who run @command{guix pull}. For
2369 instance, when user @code{root} runs @command{guix pull}, this has no
2370 effect on the version of Guix that user @code{alice} sees, and vice
2371 versa@footnote{Under the hood, @command{guix pull} updates the
2372 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2373 and the @command{guix} command loads code from there. Currently, the
2374 only way to roll back an invocation of @command{guix pull} is to
2375 manually update this symlink to point to the previous Guix.}.
2377 The @command{guix pull} command is usually invoked with no arguments,
2378 but it supports the following options:
2382 Produce verbose output, writing build logs to the standard error output.
2384 @item --url=@var{url}
2385 Download the source tarball of Guix from @var{url}.
2387 By default, the tarball is taken from its canonical address at
2388 @code{gnu.org}, for the stable branch of Guix.
2390 With some Git servers, this can be used to deploy any version of Guix.
2391 For example, to download and deploy version 0.12.0 of Guix from the
2395 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2398 It can also be used to deploy arbitrary Git revisions:
2401 guix pull --url=https://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2405 Use the bootstrap Guile to build the latest Guix. This option is only
2406 useful to Guix developers.
2409 In addition, @command{guix pull} supports all the common build options
2410 (@pxref{Common Build Options}).
2412 @node Invoking guix pack
2413 @section Invoking @command{guix pack}
2415 Occasionally you want to pass software to people who are not (yet!)
2416 lucky enough to be using Guix. You'd tell them to run @command{guix
2417 package -i @var{something}}, but that's not possible in this case. This
2418 is where @command{guix pack} comes in.
2422 @cindex application bundle
2423 @cindex software bundle
2424 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2425 @dfn{software bundle}: it creates a tarball or some other archive
2426 containing the binaries of the software you're interested in, and all
2427 its dependencies. The resulting archive can be used on any machine that
2428 does not have Guix, and people can run the exact same binaries as those
2429 you have with Guix. The pack itself is created in a bit-reproducible
2430 fashion, so anyone can verify that it really contains the build results
2431 that you pretend to be shipping.
2433 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2434 their dependencies, you can run:
2437 $ guix pack guile emacs geiser
2439 /gnu/store/@dots{}-pack.tar.gz
2442 The result here is a tarball containing a @file{/gnu/store} directory
2443 with all the relevant packages. The resulting tarball contains a
2444 @dfn{profile} with the three packages of interest; the profile is the
2445 same as would be created by @command{guix package -i}. It is this
2446 mechanism that is used to create Guix's own standalone binary tarball
2447 (@pxref{Binary Installation}).
2449 Users of this pack would have to run
2450 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2451 find inconvenient. To work around it, you can create, say, a
2452 @file{/opt/gnu/bin} symlink to the profile:
2455 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2459 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2461 Alternatively, you can produce a pack in the Docker image format using
2462 the following command:
2465 guix pack -f docker guile emacs geiser
2469 The result is a tarball that can be passed to the @command{docker load}
2471 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2472 documentation} for more information.
2474 Several command-line options allow you to customize your pack:
2477 @item --format=@var{format}
2478 @itemx -f @var{format}
2479 Produce a pack in the given @var{format}.
2481 The available formats are:
2485 This is the default format. It produces a tarball containing all the
2486 specifies binaries and symlinks.
2489 This produces a tarball that follows the
2490 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2491 Docker Image Specification}.
2494 @item --expression=@var{expr}
2495 @itemx -e @var{expr}
2496 Consider the package @var{expr} evaluates to.
2498 This has the same purpose as the same-named option in @command{guix
2499 build} (@pxref{Additional Build Options, @code{--expression} in
2500 @command{guix build}}).
2502 @item --system=@var{system}
2503 @itemx -s @var{system}
2504 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2505 the system type of the build host.
2507 @item --target=@var{triplet}
2508 @cindex cross-compilation
2509 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2510 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2511 configuration triplets,, autoconf, Autoconf}).
2513 @item --compression=@var{tool}
2514 @itemx -C @var{tool}
2515 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2516 @code{bzip2}, @code{xz}, or @code{lzip}.
2518 @item --symlink=@var{spec}
2519 @itemx -S @var{spec}
2520 Add the symlinks specified by @var{spec} to the pack. This option can
2521 appear several times.
2523 @var{spec} has the form @code{@var{source}=@var{target}}, where
2524 @var{source} is the symlink that will be created and @var{target} is the
2527 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2528 symlink pointing to the @file{bin} sub-directory of the profile.
2530 @item --localstatedir
2531 Include the ``local state directory'', @file{/var/guix}, in the
2534 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2535 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2536 the pack means that the store is ``complete'' and manageable by Guix;
2537 not providing it pack means that the store is ``dead'': items cannot be
2538 added to it or removed from it after extraction of the pack.
2540 One use case for this is the Guix self-contained binary tarball
2541 (@pxref{Binary Installation}).
2544 In addition, @command{guix pack} supports all the common build options
2545 (@pxref{Common Build Options}) and all the package transformation
2546 options (@pxref{Package Transformation Options}).
2549 @node Invoking guix archive
2550 @section Invoking @command{guix archive}
2552 @cindex @command{guix archive}
2554 The @command{guix archive} command allows users to @dfn{export} files
2555 from the store into a single archive, and to later @dfn{import} them.
2556 In particular, it allows store files to be transferred from one machine
2557 to the store on another machine.
2559 @cindex exporting store items
2560 To export store files as an archive to standard output, run:
2563 guix archive --export @var{options} @var{specifications}...
2566 @var{specifications} may be either store file names or package
2567 specifications, as for @command{guix package} (@pxref{Invoking guix
2568 package}). For instance, the following command creates an archive
2569 containing the @code{gui} output of the @code{git} package and the main
2570 output of @code{emacs}:
2573 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2576 If the specified packages are not built yet, @command{guix archive}
2577 automatically builds them. The build process may be controlled with the
2578 common build options (@pxref{Common Build Options}).
2580 To transfer the @code{emacs} package to a machine connected over SSH,
2584 guix archive --export -r emacs | ssh the-machine guix archive --import
2588 Similarly, a complete user profile may be transferred from one machine
2589 to another like this:
2592 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2593 ssh the-machine guix-archive --import
2597 However, note that, in both examples, all of @code{emacs} and the
2598 profile as well as all of their dependencies are transferred (due to
2599 @code{-r}), regardless of what is already available in the store on the
2600 target machine. The @code{--missing} option can help figure out which
2601 items are missing from the target store. The @command{guix copy}
2602 command simplifies and optimizes this whole process, so this is probably
2603 what you should use in this case (@pxref{Invoking guix copy}).
2605 @cindex nar, archive format
2606 @cindex normalized archive (nar)
2607 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2608 comparable in spirit to `tar', but with differences
2609 that make it more appropriate for our purposes. First, rather than
2610 recording all Unix metadata for each file, the nar format only mentions
2611 the file type (regular, directory, or symbolic link); Unix permissions
2612 and owner/group are dismissed. Second, the order in which directory
2613 entries are stored always follows the order of file names according to
2614 the C locale collation order. This makes archive production fully
2617 When exporting, the daemon digitally signs the contents of the archive,
2618 and that digital signature is appended. When importing, the daemon
2619 verifies the signature and rejects the import in case of an invalid
2620 signature or if the signing key is not authorized.
2621 @c FIXME: Add xref to daemon doc about signatures.
2623 The main options are:
2627 Export the specified store files or packages (see below.) Write the
2628 resulting archive to the standard output.
2630 Dependencies are @emph{not} included in the output, unless
2631 @code{--recursive} is passed.
2635 When combined with @code{--export}, this instructs @command{guix
2636 archive} to include dependencies of the given items in the archive.
2637 Thus, the resulting archive is self-contained: it contains the closure
2638 of the exported store items.
2641 Read an archive from the standard input, and import the files listed
2642 therein into the store. Abort if the archive has an invalid digital
2643 signature, or if it is signed by a public key not among the authorized
2644 keys (see @code{--authorize} below.)
2647 Read a list of store file names from the standard input, one per line,
2648 and write on the standard output the subset of these files missing from
2651 @item --generate-key[=@var{parameters}]
2652 @cindex signing, archives
2653 Generate a new key pair for the daemon. This is a prerequisite before
2654 archives can be exported with @code{--export}. Note that this operation
2655 usually takes time, because it needs to gather enough entropy to
2656 generate the key pair.
2658 The generated key pair is typically stored under @file{/etc/guix}, in
2659 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2660 key, which must be kept secret.) When @var{parameters} is omitted,
2661 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2662 versions before 1.6.0, it is a 4096-bit RSA key.
2663 Alternatively, @var{parameters} can specify
2664 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2665 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2666 Libgcrypt Reference Manual}).
2669 @cindex authorizing, archives
2670 Authorize imports signed by the public key passed on standard input.
2671 The public key must be in ``s-expression advanced format''---i.e., the
2672 same format as the @file{signing-key.pub} file.
2674 The list of authorized keys is kept in the human-editable file
2675 @file{/etc/guix/acl}. The file contains
2676 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2677 s-expressions''} and is structured as an access-control list in the
2678 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2681 @item --extract=@var{directory}
2682 @itemx -x @var{directory}
2683 Read a single-item archive as served by substitute servers
2684 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2685 low-level operation needed in only very narrow use cases; see below.
2687 For example, the following command extracts the substitute for Emacs
2688 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2692 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2693 | bunzip2 | guix archive -x /tmp/emacs
2696 Single-item archives are different from multiple-item archives produced
2697 by @command{guix archive --export}; they contain a single store item,
2698 and they do @emph{not} embed a signature. Thus this operation does
2699 @emph{no} signature verification and its output should be considered
2702 The primary purpose of this operation is to facilitate inspection of
2703 archive contents coming from possibly untrusted substitute servers.
2707 @c *********************************************************************
2708 @node Programming Interface
2709 @chapter Programming Interface
2711 GNU Guix provides several Scheme programming interfaces (APIs) to
2712 define, build, and query packages. The first interface allows users to
2713 write high-level package definitions. These definitions refer to
2714 familiar packaging concepts, such as the name and version of a package,
2715 its build system, and its dependencies. These definitions can then be
2716 turned into concrete build actions.
2718 Build actions are performed by the Guix daemon, on behalf of users. In a
2719 standard setup, the daemon has write access to the store---the
2720 @file{/gnu/store} directory---whereas users do not. The recommended
2721 setup also has the daemon perform builds in chroots, under a specific
2722 build users, to minimize interference with the rest of the system.
2725 Lower-level APIs are available to interact with the daemon and the
2726 store. To instruct the daemon to perform a build action, users actually
2727 provide it with a @dfn{derivation}. A derivation is a low-level
2728 representation of the build actions to be taken, and the environment in
2729 which they should occur---derivations are to package definitions what
2730 assembly is to C programs. The term ``derivation'' comes from the fact
2731 that build results @emph{derive} from them.
2733 This chapter describes all these APIs in turn, starting from high-level
2734 package definitions.
2737 * Defining Packages:: Defining new packages.
2738 * Build Systems:: Specifying how packages are built.
2739 * The Store:: Manipulating the package store.
2740 * Derivations:: Low-level interface to package derivations.
2741 * The Store Monad:: Purely functional interface to the store.
2742 * G-Expressions:: Manipulating build expressions.
2745 @node Defining Packages
2746 @section Defining Packages
2748 The high-level interface to package definitions is implemented in the
2749 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2750 example, the package definition, or @dfn{recipe}, for the GNU Hello
2751 package looks like this:
2754 (define-module (gnu packages hello)
2755 #:use-module (guix packages)
2756 #:use-module (guix download)
2757 #:use-module (guix build-system gnu)
2758 #:use-module (guix licenses)
2759 #:use-module (gnu packages gawk))
2761 (define-public hello
2767 (uri (string-append "mirror://gnu/hello/hello-" version
2771 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2772 (build-system gnu-build-system)
2773 (arguments '(#:configure-flags '("--enable-silent-rules")))
2774 (inputs `(("gawk" ,gawk)))
2775 (synopsis "Hello, GNU world: An example GNU package")
2776 (description "Guess what GNU Hello prints!")
2777 (home-page "http://www.gnu.org/software/hello/")
2782 Without being a Scheme expert, the reader may have guessed the meaning
2783 of the various fields here. This expression binds the variable
2784 @code{hello} to a @code{<package>} object, which is essentially a record
2785 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2786 This package object can be inspected using procedures found in the
2787 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2788 returns---surprise!---@code{"hello"}.
2790 With luck, you may be able to import part or all of the definition of
2791 the package you are interested in from another repository, using the
2792 @code{guix import} command (@pxref{Invoking guix import}).
2794 In the example above, @var{hello} is defined in a module of its own,
2795 @code{(gnu packages hello)}. Technically, this is not strictly
2796 necessary, but it is convenient to do so: all the packages defined in
2797 modules under @code{(gnu packages @dots{})} are automatically known to
2798 the command-line tools (@pxref{Package Modules}).
2800 There are a few points worth noting in the above package definition:
2804 The @code{source} field of the package is an @code{<origin>} object
2805 (@pxref{origin Reference}, for the complete reference).
2806 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2807 meaning that the source is a file to be downloaded over FTP or HTTP.
2809 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2810 the GNU mirrors defined in @code{(guix download)}.
2812 The @code{sha256} field specifies the expected SHA256 hash of the file
2813 being downloaded. It is mandatory, and allows Guix to check the
2814 integrity of the file. The @code{(base32 @dots{})} form introduces the
2815 base32 representation of the hash. You can obtain this information with
2816 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2817 hash} (@pxref{Invoking guix hash}).
2820 When needed, the @code{origin} form can also have a @code{patches} field
2821 listing patches to be applied, and a @code{snippet} field giving a
2822 Scheme expression to modify the source code.
2825 @cindex GNU Build System
2826 The @code{build-system} field specifies the procedure to build the
2827 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2828 represents the familiar GNU Build System, where packages may be
2829 configured, built, and installed with the usual @code{./configure &&
2830 make && make check && make install} command sequence.
2833 The @code{arguments} field specifies options for the build system
2834 (@pxref{Build Systems}). Here it is interpreted by
2835 @var{gnu-build-system} as a request run @file{configure} with the
2836 @code{--enable-silent-rules} flag.
2842 What about these quote (@code{'}) characters? They are Scheme syntax to
2843 introduce a literal list; @code{'} is synonymous with @code{quote}.
2844 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2845 for details. Here the value of the @code{arguments} field is a list of
2846 arguments passed to the build system down the road, as with @code{apply}
2847 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2850 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2851 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2852 @code{#:configure-flags} is a keyword used to pass a keyword argument
2853 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2857 The @code{inputs} field specifies inputs to the build process---i.e.,
2858 build-time or run-time dependencies of the package. Here, we define an
2859 input called @code{"gawk"} whose value is that of the @var{gawk}
2860 variable; @var{gawk} is itself bound to a @code{<package>} object.
2862 @cindex backquote (quasiquote)
2865 @cindex comma (unquote)
2869 @findex unquote-splicing
2870 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2871 us to introduce a literal list in the @code{inputs} field, while
2872 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2873 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2876 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2877 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2878 of ensuring that they are present (@pxref{Build Systems}).
2880 However, any other dependencies need to be specified in the
2881 @code{inputs} field. Any dependency not specified here will simply be
2882 unavailable to the build process, possibly leading to a build failure.
2885 @xref{package Reference}, for a full description of possible fields.
2887 Once a package definition is in place, the
2888 package may actually be built using the @code{guix build} command-line
2889 tool (@pxref{Invoking guix build}), troubleshooting any build failures
2890 you encounter (@pxref{Debugging Build Failures}). You can easily jump back to the
2891 package definition using the @command{guix edit} command
2892 (@pxref{Invoking guix edit}).
2893 @xref{Packaging Guidelines}, for
2894 more information on how to test package definitions, and
2895 @ref{Invoking guix lint}, for information on how to check a definition
2896 for style conformance.
2897 @vindex GUIX_PACKAGE_PATH
2898 Lastly, @pxref{Package Modules}, for information
2899 on how to extend the distribution by adding your own package definitions
2900 to @code{GUIX_PACKAGE_PATH}.
2902 Finally, updating the package definition to a new upstream version
2903 can be partly automated by the @command{guix refresh} command
2904 (@pxref{Invoking guix refresh}).
2906 Behind the scenes, a derivation corresponding to the @code{<package>}
2907 object is first computed by the @code{package-derivation} procedure.
2908 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2909 The build actions it prescribes may then be realized by using the
2910 @code{build-derivations} procedure (@pxref{The Store}).
2912 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2913 Return the @code{<derivation>} object of @var{package} for @var{system}
2914 (@pxref{Derivations}).
2916 @var{package} must be a valid @code{<package>} object, and @var{system}
2917 must be a string denoting the target system type---e.g.,
2918 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2919 must be a connection to the daemon, which operates on the store
2920 (@pxref{The Store}).
2924 @cindex cross-compilation
2925 Similarly, it is possible to compute a derivation that cross-builds a
2926 package for some other system:
2928 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2929 @var{package} @var{target} [@var{system}]
2930 Return the @code{<derivation>} object of @var{package} cross-built from
2931 @var{system} to @var{target}.
2933 @var{target} must be a valid GNU triplet denoting the target hardware
2934 and operating system, such as @code{"mips64el-linux-gnu"}
2935 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2936 Configure and Build System}).
2939 @cindex package transformations
2940 @cindex input rewriting
2941 @cindex dependency tree rewriting
2942 Packages can be manipulated in arbitrary ways. An example of a useful
2943 transformation is @dfn{input rewriting}, whereby the dependency tree of
2944 a package is rewritten by replacing specific inputs by others:
2946 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2947 [@var{rewrite-name}]
2948 Return a procedure that, when passed a package, replaces its direct and
2949 indirect dependencies (but not its implicit inputs) according to
2950 @var{replacements}. @var{replacements} is a list of package pairs; the
2951 first element of each pair is the package to replace, and the second one
2954 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2955 the name of a package and returns its new name after rewrite.
2959 Consider this example:
2962 (define libressl-instead-of-openssl
2963 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2965 (package-input-rewriting `((,openssl . ,libressl))))
2967 (define git-with-libressl
2968 (libressl-instead-of-openssl git))
2972 Here we first define a rewriting procedure that replaces @var{openssl}
2973 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2974 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2975 This is exactly what the @option{--with-input} command-line option does
2976 (@pxref{Package Transformation Options, @option{--with-input}}).
2978 A more generic procedure to rewrite a package dependency graph is
2979 @code{package-mapping}: it supports arbitrary changes to nodes in the
2982 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
2983 Return a procedure that, given a package, applies @var{proc} to all the packages
2984 depended on and returns the resulting package. The procedure stops recursion
2985 when @var{cut?} returns true for a given package.
2989 * package Reference :: The package data type.
2990 * origin Reference:: The origin data type.
2994 @node package Reference
2995 @subsection @code{package} Reference
2997 This section summarizes all the options available in @code{package}
2998 declarations (@pxref{Defining Packages}).
3000 @deftp {Data Type} package
3001 This is the data type representing a package recipe.
3005 The name of the package, as a string.
3007 @item @code{version}
3008 The version of the package, as a string.
3011 An object telling how the source code for the package should be
3012 acquired. Most of the time, this is an @code{origin} object, which
3013 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3014 can also be any other ``file-like'' object such as a @code{local-file},
3015 which denotes a file from the local file system (@pxref{G-Expressions,
3016 @code{local-file}}).
3018 @item @code{build-system}
3019 The build system that should be used to build the package (@pxref{Build
3022 @item @code{arguments} (default: @code{'()})
3023 The arguments that should be passed to the build system. This is a
3024 list, typically containing sequential keyword-value pairs.
3026 @item @code{inputs} (default: @code{'()})
3027 @itemx @code{native-inputs} (default: @code{'()})
3028 @itemx @code{propagated-inputs} (default: @code{'()})
3029 @cindex inputs, of packages
3030 These fields list dependencies of the package. Each one is a list of
3031 tuples, where each tuple has a label for the input (a string) as its
3032 first element, a package, origin, or derivation as its second element,
3033 and optionally the name of the output thereof that should be used, which
3034 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3035 more on package outputs). For example, the list below specifies three
3039 `(("libffi" ,libffi)
3040 ("libunistring" ,libunistring)
3041 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3044 @cindex cross compilation, package dependencies
3045 The distinction between @code{native-inputs} and @code{inputs} is
3046 necessary when considering cross-compilation. When cross-compiling,
3047 dependencies listed in @code{inputs} are built for the @emph{target}
3048 architecture; conversely, dependencies listed in @code{native-inputs}
3049 are built for the architecture of the @emph{build} machine.
3051 @code{native-inputs} is typically used to list tools needed at
3052 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3053 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3054 this area (@pxref{Invoking guix lint}).
3056 @anchor{package-propagated-inputs}
3057 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3058 specified packages will be automatically installed alongside the package
3059 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3060 package}}, for information on how @command{guix package} deals with
3063 For example this is necessary when a C/C++ library needs headers of
3064 another library to compile, or when a pkg-config file refers to another
3065 one @i{via} its @code{Requires} field.
3067 Another example where @code{propagated-inputs} is useful is for languages
3068 that lack a facility to record the run-time search path akin to the
3069 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3070 more. To ensure that libraries written in those languages can find
3071 library code they depend on at run time, run-time dependencies must be
3072 listed in @code{propagated-inputs} rather than @code{inputs}.
3074 @item @code{self-native-input?} (default: @code{#f})
3075 This is a Boolean field telling whether the package should use itself as
3076 a native input when cross-compiling.
3078 @item @code{outputs} (default: @code{'("out")})
3079 The list of output names of the package. @xref{Packages with Multiple
3080 Outputs}, for typical uses of additional outputs.
3082 @item @code{native-search-paths} (default: @code{'()})
3083 @itemx @code{search-paths} (default: @code{'()})
3084 A list of @code{search-path-specification} objects describing
3085 search-path environment variables honored by the package.
3087 @item @code{replacement} (default: @code{#f})
3088 This must be either @code{#f} or a package object that will be used as a
3089 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3092 @item @code{synopsis}
3093 A one-line description of the package.
3095 @item @code{description}
3096 A more elaborate description of the package.
3098 @item @code{license}
3099 @cindex license, of packages
3100 The license of the package; a value from @code{(guix licenses)},
3101 or a list of such values.
3103 @item @code{home-page}
3104 The URL to the home-page of the package, as a string.
3106 @item @code{supported-systems} (default: @var{%supported-systems})
3107 The list of systems supported by the package, as strings of the form
3108 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3110 @item @code{maintainers} (default: @code{'()})
3111 The list of maintainers of the package, as @code{maintainer} objects.
3113 @item @code{location} (default: source location of the @code{package} form)
3114 The source location of the package. It is useful to override this when
3115 inheriting from another package, in which case this field is not
3116 automatically corrected.
3121 @node origin Reference
3122 @subsection @code{origin} Reference
3124 This section summarizes all the options available in @code{origin}
3125 declarations (@pxref{Defining Packages}).
3127 @deftp {Data Type} origin
3128 This is the data type representing a source code origin.
3132 An object containing the URI of the source. The object type depends on
3133 the @code{method} (see below). For example, when using the
3134 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3135 values are: a URL represented as a string, or a list thereof.
3138 A procedure that handles the URI.
3143 @item @var{url-fetch} from @code{(guix download)}
3144 download a file from the HTTP, HTTPS, or FTP URL specified in the
3148 @item @var{git-fetch} from @code{(guix git-download)}
3149 clone the Git version control repository, and check out the revision
3150 specified in the @code{uri} field as a @code{git-reference} object; a
3151 @code{git-reference} looks like this:
3155 (url "git://git.debian.org/git/pkg-shadow/shadow")
3156 (commit "v4.1.5.1"))
3161 A bytevector containing the SHA-256 hash of the source. Typically the
3162 @code{base32} form is used here to generate the bytevector from a
3165 You can obtain this information using @code{guix download}
3166 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3169 @item @code{file-name} (default: @code{#f})
3170 The file name under which the source code should be saved. When this is
3171 @code{#f}, a sensible default value will be used in most cases. In case
3172 the source is fetched from a URL, the file name from the URL will be
3173 used. For version control checkouts, it is recommended to provide the
3174 file name explicitly because the default is not very descriptive.
3176 @item @code{patches} (default: @code{'()})
3177 A list of file names containing patches to be applied to the source.
3179 This list of patches must be unconditional. In particular, it cannot
3180 depend on the value of @code{%current-system} or
3181 @code{%current-target-system}.
3183 @item @code{snippet} (default: @code{#f})
3184 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3185 in the source directory. This is a convenient way to modify the source,
3186 sometimes more convenient than a patch.
3188 @item @code{patch-flags} (default: @code{'("-p1")})
3189 A list of command-line flags that should be passed to the @code{patch}
3192 @item @code{patch-inputs} (default: @code{#f})
3193 Input packages or derivations to the patching process. When this is
3194 @code{#f}, the usual set of inputs necessary for patching are provided,
3195 such as GNU@tie{}Patch.
3197 @item @code{modules} (default: @code{'()})
3198 A list of Guile modules that should be loaded during the patching
3199 process and while running the code in the @code{snippet} field.
3201 @item @code{patch-guile} (default: @code{#f})
3202 The Guile package that should be used in the patching process. When
3203 this is @code{#f}, a sensible default is used.
3209 @section Build Systems
3211 @cindex build system
3212 Each package definition specifies a @dfn{build system} and arguments for
3213 that build system (@pxref{Defining Packages}). This @code{build-system}
3214 field represents the build procedure of the package, as well as implicit
3215 dependencies of that build procedure.
3217 Build systems are @code{<build-system>} objects. The interface to
3218 create and manipulate them is provided by the @code{(guix build-system)}
3219 module, and actual build systems are exported by specific modules.
3221 @cindex bag (low-level package representation)
3222 Under the hood, build systems first compile package objects to
3223 @dfn{bags}. A @dfn{bag} is like a package, but with less
3224 ornamentation---in other words, a bag is a lower-level representation of
3225 a package, which includes all the inputs of that package, including some
3226 that were implicitly added by the build system. This intermediate
3227 representation is then compiled to a derivation (@pxref{Derivations}).
3229 Build systems accept an optional list of @dfn{arguments}. In package
3230 definitions, these are passed @i{via} the @code{arguments} field
3231 (@pxref{Defining Packages}). They are typically keyword arguments
3232 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3233 Guile Reference Manual}). The value of these arguments is usually
3234 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3235 by the daemon (@pxref{Derivations}).
3237 The main build system is @var{gnu-build-system}, which implements the
3238 standard build procedure for GNU and many other packages. It
3239 is provided by the @code{(guix build-system gnu)} module.
3241 @defvr {Scheme Variable} gnu-build-system
3242 @var{gnu-build-system} represents the GNU Build System, and variants
3243 thereof (@pxref{Configuration, configuration and makefile conventions,,
3244 standards, GNU Coding Standards}).
3246 @cindex build phases
3247 In a nutshell, packages using it are configured, built, and installed with
3248 the usual @code{./configure && make && make check && make install}
3249 command sequence. In practice, a few additional steps are often needed.
3250 All these steps are split up in separate @dfn{phases},
3251 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3252 modules for more details about the build phases.}:
3256 Unpack the source tarball, and change the current directory to the
3257 extracted source tree. If the source is actually a directory, copy it
3258 to the build tree, and enter that directory.
3260 @item patch-source-shebangs
3261 Patch shebangs encountered in source files so they refer to the right
3262 store file names. For instance, this changes @code{#!/bin/sh} to
3263 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3266 Run the @file{configure} script with a number of default options, such
3267 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3268 by the @code{#:configure-flags} argument.
3271 Run @code{make} with the list of flags specified with
3272 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3273 (the default), build with @code{make -j}.
3276 Run @code{make check}, or some other target specified with
3277 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3278 @code{#:parallel-tests?} argument is true (the default), run @code{make
3282 Run @code{make install} with the flags listed in @code{#:make-flags}.
3284 @item patch-shebangs
3285 Patch shebangs on the installed executable files.
3288 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3289 is false), copying them to the @code{debug} output when available
3290 (@pxref{Installing Debugging Files}).
3293 @vindex %standard-phases
3294 The build-side module @code{(guix build gnu-build-system)} defines
3295 @var{%standard-phases} as the default list of build phases.
3296 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3297 procedure implements the actual phase.
3299 The list of phases used for a particular package can be changed with the
3300 @code{#:phases} parameter. For instance, passing:
3303 #:phases (modify-phases %standard-phases (delete 'configure))
3306 means that all the phases described above will be used, except the
3307 @code{configure} phase.
3309 In addition, this build system ensures that the ``standard'' environment
3310 for GNU packages is available. This includes tools such as GCC, libc,
3311 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3312 build-system gnu)} module for a complete list). We call these the
3313 @dfn{implicit inputs} of a package, because package definitions do not
3314 have to mention them.
3317 Other @code{<build-system>} objects are defined to support other
3318 conventions and tools used by free software packages. They inherit most
3319 of @var{gnu-build-system}, and differ mainly in the set of inputs
3320 implicitly added to the build process, and in the list of phases
3321 executed. Some of these build systems are listed below.
3323 @defvr {Scheme Variable} ant-build-system
3324 This variable is exported by @code{(guix build-system ant)}. It
3325 implements the build procedure for Java packages that can be built with
3326 @url{http://ant.apache.org/, Ant build tool}.
3328 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3329 provided by the @code{icedtea} package to the set of inputs. Different
3330 packages can be specified with the @code{#:ant} and @code{#:jdk}
3331 parameters, respectively.
3333 When the original package does not provide a suitable Ant build file,
3334 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3335 build file @file{build.xml} with tasks to build the specified jar
3336 archive. In this case the parameter @code{#:source-dir} can be used to
3337 specify the source sub-directory, defaulting to ``src''.
3339 The parameter @code{#:build-target} can be used to specify the Ant task
3340 that should be run during the @code{build} phase. By default the
3341 ``jar'' task will be run.
3345 @defvr {Scheme Variable} asdf-build-system/source
3346 @defvrx {Scheme Variable} asdf-build-system/sbcl
3347 @defvrx {Scheme Variable} asdf-build-system/ecl
3349 These variables, exported by @code{(guix build-system asdf)}, implement
3350 build procedures for Common Lisp packages using
3351 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3352 definition facility for Common Lisp programs and libraries.
3354 The @code{asdf-build-system/source} system installs the packages in
3355 source form, and can be loaded using any common lisp implementation, via
3356 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3357 systems in the format which a particular implementation understands.
3358 These build systems can also be used to produce executable programs, or
3359 lisp images which contain a set of packages pre-loaded.
3361 The build system uses naming conventions. For binary packages, the
3362 package name should be prefixed with the lisp implementation, such as
3363 @code{sbcl-} for @code{asdf-build-system/sbcl}.
3365 Additionally, the corresponding source package should be labeled using
3366 the same convention as python packages (see @ref{Python Modules}), using
3367 the @code{cl-} prefix.
3369 For binary packages, each system should be defined as a Guix package.
3370 If one package @code{origin} contains several systems, package variants
3371 can be created in order to build all the systems. Source packages,
3372 which use @code{asdf-build-system/source}, may contain several systems.
3374 In order to create executable programs and images, the build-side
3375 procedures @code{build-program} and @code{build-image} can be used.
3376 They should be called in a build phase after the @code{create-symlinks}
3377 phase, so that the system which was just built can be used within the
3378 resulting image. @code{build-program} requires a list of Common Lisp
3379 expressions to be passed as the @code{#:entry-program} argument.
3381 If the system is not defined within its own @code{.asd} file of the same
3382 name, then the @code{#:asd-file} parameter should be used to specify
3383 which file the system is defined in. Furthermore, if the package
3384 defines a system for its tests in a separate file, it will be loaded
3385 before the tests are run if it is specified by the
3386 @code{#:test-asd-file} parameter. If it is not set, the files
3387 @code{<system>-tests.asd}, @code{<system>-test.asd}, @code{tests.asd},
3388 and @code{test.asd} will be tried if they exist.
3390 If for some reason the package must be named in a different way than the
3391 naming conventions suggest, the @code{#:asd-system-name} parameter can
3392 be used to specify the name of the system.
3396 @defvr {Scheme Variable} cargo-build-system
3397 @cindex Rust programming language
3398 @cindex Cargo (Rust build system)
3399 This variable is exported by @code{(guix build-system cargo)}. It
3400 supports builds of packages using Cargo, the build tool of the
3401 @uref{https://www.rust-lang.org, Rust programming language}.
3403 In its @code{configure} phase, this build system replaces dependencies
3404 specified in the @file{Carto.toml} file with inputs to the Guix package.
3405 The @code{install} phase installs the binaries, and it also installs the
3406 source code and @file{Cargo.toml} file.
3409 @defvr {Scheme Variable} cmake-build-system
3410 This variable is exported by @code{(guix build-system cmake)}. It
3411 implements the build procedure for packages using the
3412 @url{http://www.cmake.org, CMake build tool}.
3414 It automatically adds the @code{cmake} package to the set of inputs.
3415 Which package is used can be specified with the @code{#:cmake}
3418 The @code{#:configure-flags} parameter is taken as a list of flags
3419 passed to the @command{cmake} command. The @code{#:build-type}
3420 parameter specifies in abstract terms the flags passed to the compiler;
3421 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3422 debugging information''), which roughly means that code is compiled with
3423 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3426 @defvr {Scheme Variable} glib-or-gtk-build-system
3427 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3428 is intended for use with packages making use of GLib or GTK+.
3430 This build system adds the following two phases to the ones defined by
3431 @var{gnu-build-system}:
3434 @item glib-or-gtk-wrap
3435 The phase @code{glib-or-gtk-wrap} ensures that programs in
3436 @file{bin/} are able to find GLib ``schemas'' and
3437 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3438 modules}. This is achieved by wrapping the programs in launch scripts
3439 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3440 environment variables.
3442 It is possible to exclude specific package outputs from that wrapping
3443 process by listing their names in the
3444 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3445 when an output is known not to contain any GLib or GTK+ binaries, and
3446 where wrapping would gratuitously add a dependency of that output on
3449 @item glib-or-gtk-compile-schemas
3450 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3451 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3452 GSettings schemas} of GLib are compiled. Compilation is performed by the
3453 @command{glib-compile-schemas} program. It is provided by the package
3454 @code{glib:bin} which is automatically imported by the build system.
3455 The @code{glib} package providing @command{glib-compile-schemas} can be
3456 specified with the @code{#:glib} parameter.
3459 Both phases are executed after the @code{install} phase.
3462 @defvr {Scheme Variable} ocaml-build-system
3463 This variable is exported by @code{(guix build-system ocaml)}. It implements
3464 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3465 of choosing the correct set of commands to run for each package. OCaml
3466 packages can expect many different commands to be run. This build system will
3469 When the package has a @file{setup.ml} file present at the top-level, it will
3470 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3471 @code{ocaml setup.ml -install}. The build system will assume that this file
3472 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3473 care of setting the prefix and enabling tests if they are not disabled. You
3474 can pass configure and build flags with the @code{#:configure-flags} and
3475 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3476 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3477 bypass this system in the build and install phases.
3479 When the package has a @file{configure} file, it is assumed that it is a
3480 hand-made configure script that requires a different argument format than
3481 in the @code{gnu-build-system}. You can add more flags with the
3482 @code{#:configure-flags} key.
3484 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3485 @code{#t}), it will be used and more flags can be passed to the build and
3486 install phases with the @code{#:make-flags} key.
3488 Finally, some packages do not have these files and use a somewhat standard
3489 location for its build system. In that case, the build system will run
3490 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3491 providing the path to the required findlib module. Additional flags can
3492 be passed via the @code{#:build-flags} key. Install is taken care of by
3493 @command{opam-installer}. In this case, the @code{opam} package must
3494 be added to the @code{native-inputs} field of the package definition.
3496 Note that most OCaml packages assume they will be installed in the same
3497 directory as OCaml, which is not what we want in guix. In particular, they
3498 will install @file{.so} files in their module's directory, which is usually
3499 fine because it is in the OCaml compiler directory. In guix though, these
3500 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3501 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3502 @file{.so} libraries should be installed.
3505 @defvr {Scheme Variable} python-build-system
3506 This variable is exported by @code{(guix build-system python)}. It
3507 implements the more or less standard build procedure used by Python
3508 packages, which consists in running @code{python setup.py build} and
3509 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3511 For packages that install stand-alone Python programs under @code{bin/},
3512 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3513 environment variable points to all the Python libraries they depend on.
3515 Which Python package is used to perform the build can be specified with
3516 the @code{#:python} parameter. This is a useful way to force a package
3517 to be built for a specific version of the Python interpreter, which
3518 might be necessary if the package is only compatible with a single
3519 interpreter version.
3521 By default guix calls @code{setup.py} under control of
3522 @code{setuptools}, much like @command{pip} does. Some packages are not
3523 compatible with setuptools (and pip), thus you can disable this by
3524 setting the @code{#:use-setuptools} parameter to @code{#f}.
3527 @defvr {Scheme Variable} perl-build-system
3528 This variable is exported by @code{(guix build-system perl)}. It
3529 implements the standard build procedure for Perl packages, which either
3530 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3531 followed by @code{Build} and @code{Build install}; or in running
3532 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3533 @code{make} and @code{make install}, depending on which of
3534 @code{Build.PL} or @code{Makefile.PL} is present in the package
3535 distribution. Preference is given to the former if both @code{Build.PL}
3536 and @code{Makefile.PL} exist in the package distribution. This
3537 preference can be reversed by specifying @code{#t} for the
3538 @code{#:make-maker?} parameter.
3540 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3541 passes flags specified by the @code{#:make-maker-flags} or
3542 @code{#:module-build-flags} parameter, respectively.
3544 Which Perl package is used can be specified with @code{#:perl}.
3547 @defvr {Scheme Variable} r-build-system
3548 This variable is exported by @code{(guix build-system r)}. It
3549 implements the build procedure used by @uref{http://r-project.org, R}
3550 packages, which essentially is little more than running @code{R CMD
3551 INSTALL --library=/gnu/store/@dots{}} in an environment where
3552 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3553 are run after installation using the R function
3554 @code{tools::testInstalledPackage}.
3557 @defvr {Scheme Variable} ruby-build-system
3558 This variable is exported by @code{(guix build-system ruby)}. It
3559 implements the RubyGems build procedure used by Ruby packages, which
3560 involves running @code{gem build} followed by @code{gem install}.
3562 The @code{source} field of a package that uses this build system
3563 typically references a gem archive, since this is the format that Ruby
3564 developers use when releasing their software. The build system unpacks
3565 the gem archive, potentially patches the source, runs the test suite,
3566 repackages the gem, and installs it. Additionally, directories and
3567 tarballs may be referenced to allow building unreleased gems from Git or
3568 a traditional source release tarball.
3570 Which Ruby package is used can be specified with the @code{#:ruby}
3571 parameter. A list of additional flags to be passed to the @command{gem}
3572 command can be specified with the @code{#:gem-flags} parameter.
3575 @defvr {Scheme Variable} waf-build-system
3576 This variable is exported by @code{(guix build-system waf)}. It
3577 implements a build procedure around the @code{waf} script. The common
3578 phases---@code{configure}, @code{build}, and @code{install}---are
3579 implemented by passing their names as arguments to the @code{waf}
3582 The @code{waf} script is executed by the Python interpreter. Which
3583 Python package is used to run the script can be specified with the
3584 @code{#:python} parameter.
3587 @defvr {Scheme Variable} haskell-build-system
3588 This variable is exported by @code{(guix build-system haskell)}. It
3589 implements the Cabal build procedure used by Haskell packages, which
3590 involves running @code{runhaskell Setup.hs configure
3591 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3592 Instead of installing the package by running @code{runhaskell Setup.hs
3593 install}, to avoid trying to register libraries in the read-only
3594 compiler store directory, the build system uses @code{runhaskell
3595 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3596 addition, the build system generates the package documentation by
3597 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3598 is passed. Optional Haddock parameters can be passed with the help of
3599 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3600 not found, the build system looks for @code{Setup.lhs} instead.
3602 Which Haskell compiler is used can be specified with the @code{#:haskell}
3603 parameter which defaults to @code{ghc}.
3606 @defvr {Scheme Variable} dub-build-system
3607 This variable is exported by @code{(guix build-system dub)}. It
3608 implements the Dub build procedure used by D packages, which
3609 involves running @code{dub build} and @code{dub run}.
3610 Installation is done by copying the files manually.
3612 Which D compiler is used can be specified with the @code{#:ldc}
3613 parameter which defaults to @code{ldc}.
3616 @defvr {Scheme Variable} emacs-build-system
3617 This variable is exported by @code{(guix build-system emacs)}. It
3618 implements an installation procedure similar to the packaging system
3619 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3621 It first creates the @code{@var{package}-autoloads.el} file, then it
3622 byte compiles all Emacs Lisp files. Differently from the Emacs
3623 packaging system, the Info documentation files are moved to the standard
3624 documentation directory and the @file{dir} file is deleted. Each
3625 package is installed in its own directory under
3626 @file{share/emacs/site-lisp/guix.d}.
3629 Lastly, for packages that do not need anything as sophisticated, a
3630 ``trivial'' build system is provided. It is trivial in the sense that
3631 it provides basically no support: it does not pull any implicit inputs,
3632 and does not have a notion of build phases.
3634 @defvr {Scheme Variable} trivial-build-system
3635 This variable is exported by @code{(guix build-system trivial)}.
3637 This build system requires a @code{#:builder} argument. This argument
3638 must be a Scheme expression that builds the package output(s)---as
3639 with @code{build-expression->derivation} (@pxref{Derivations,
3640 @code{build-expression->derivation}}).
3650 Conceptually, the @dfn{store} is the place where derivations that have
3651 been built successfully are stored---by default, @file{/gnu/store}.
3652 Sub-directories in the store are referred to as @dfn{store items} or
3653 sometimes @dfn{store paths}. The store has an associated database that
3654 contains information such as the store paths referred to by each store
3655 path, and the list of @emph{valid} store items---results of successful
3656 builds. This database resides in @file{@var{localstatedir}/guix/db},
3657 where @var{localstatedir} is the state directory specified @i{via}
3658 @option{--localstatedir} at configure time, usually @file{/var}.
3660 The store is @emph{always} accessed by the daemon on behalf of its clients
3661 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3662 connect to the daemon over a Unix-domain socket, send requests to it,
3663 and read the result---these are remote procedure calls, or RPCs.
3666 Users must @emph{never} modify files under @file{/gnu/store} directly.
3667 This would lead to inconsistencies and break the immutability
3668 assumptions of Guix's functional model (@pxref{Introduction}).
3670 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3671 how to check the integrity of the store and attempt recovery from
3672 accidental modifications.
3675 The @code{(guix store)} module provides procedures to connect to the
3676 daemon, and to perform RPCs. These are described below. By default,
3677 @code{open-connection}, and thus all the @command{guix} commands,
3678 connect to the local daemon or to the URI specified by the
3679 @code{GUIX_DAEMON_SOCKET} environment variable.
3681 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3682 When set, the value of this variable should be a file name or a URI
3683 designating the daemon endpoint. When it is a file name, it denotes a
3684 Unix-domain socket to connect to. In addition to file names, the
3685 supported URI schemes are:
3690 These are for Unix-domain sockets.
3691 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3692 @file{/var/guix/daemon-socket/socket}.
3695 These URIs denote connections over TCP/IP, without encryption nor
3696 authentication of the remote host. The URI must always specify both the
3697 host name and port number:
3700 guix://master.guix.example.org:1234
3703 This setup is suitable on local networks, such as clusters, where only
3704 trusted nodes may connect to the build daemon at
3705 @code{master.guix.example.org}.
3708 @cindex SSH access to build daemons
3709 These URIs allow you to connect to a remote daemon over
3710 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3711 A typical URL might look like this:
3714 ssh://charlie@@guix.example.org:22
3717 As for @command{guix copy}, the usual OpenSSH client configuration files
3718 are honored (@pxref{Invoking guix copy}).
3721 Additional URI schemes may be supported in the future.
3723 @c XXX: Remove this note when the protocol incurs fewer round trips
3724 @c and when (guix derivations) no longer relies on file system access.
3726 The ability to connect to remote build daemons is considered
3727 experimental as of @value{VERSION}. Please get in touch with us to
3728 share any problems or suggestions you may have (@pxref{Contributing}).
3732 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3733 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3734 @var{reserve-space?} is true, instruct it to reserve a little bit of
3735 extra space on the file system so that the garbage collector can still
3736 operate should the disk become full. Return a server object.
3738 @var{file} defaults to @var{%default-socket-path}, which is the normal
3739 location given the options that were passed to @command{configure}.
3742 @deffn {Scheme Procedure} close-connection @var{server}
3743 Close the connection to @var{server}.
3746 @defvr {Scheme Variable} current-build-output-port
3747 This variable is bound to a SRFI-39 parameter, which refers to the port
3748 where build and error logs sent by the daemon should be written.
3751 Procedures that make RPCs all take a server object as their first
3754 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3755 @cindex invalid store items
3756 Return @code{#t} when @var{path} designates a valid store item and
3757 @code{#f} otherwise (an invalid item may exist on disk but still be
3758 invalid, for instance because it is the result of an aborted or failed
3761 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3762 prefixed by the store directory (@file{/gnu/store}).
3765 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3766 Add @var{text} under file @var{name} in the store, and return its store
3767 path. @var{references} is the list of store paths referred to by the
3768 resulting store path.
3771 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3772 Build @var{derivations} (a list of @code{<derivation>} objects or
3773 derivation paths), and return when the worker is done building them.
3774 Return @code{#t} on success.
3777 Note that the @code{(guix monads)} module provides a monad as well as
3778 monadic versions of the above procedures, with the goal of making it
3779 more convenient to work with code that accesses the store (@pxref{The
3783 @i{This section is currently incomplete.}
3786 @section Derivations
3789 Low-level build actions and the environment in which they are performed
3790 are represented by @dfn{derivations}. A derivation contains the
3791 following pieces of information:
3795 The outputs of the derivation---derivations produce at least one file or
3796 directory in the store, but may produce more.
3799 The inputs of the derivations, which may be other derivations or plain
3800 files in the store (patches, build scripts, etc.)
3803 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3806 The file name of a build script in the store, along with the arguments
3810 A list of environment variables to be defined.
3814 @cindex derivation path
3815 Derivations allow clients of the daemon to communicate build actions to
3816 the store. They exist in two forms: as an in-memory representation,
3817 both on the client- and daemon-side, and as files in the store whose
3818 name end in @code{.drv}---these files are referred to as @dfn{derivation
3819 paths}. Derivations paths can be passed to the @code{build-derivations}
3820 procedure to perform the build actions they prescribe (@pxref{The
3823 The @code{(guix derivations)} module provides a representation of
3824 derivations as Scheme objects, along with procedures to create and
3825 otherwise manipulate derivations. The lowest-level primitive to create
3826 a derivation is the @code{derivation} procedure:
3828 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3829 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3830 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3831 [#:system (%current-system)] [#:references-graphs #f] @
3832 [#:allowed-references #f] [#:disallowed-references #f] @
3833 [#:leaked-env-vars #f] [#:local-build? #f] @
3834 [#:substitutable? #t]
3835 Build a derivation with the given arguments, and return the resulting
3836 @code{<derivation>} object.
3838 When @var{hash} and @var{hash-algo} are given, a
3839 @dfn{fixed-output derivation} is created---i.e., one whose result is
3840 known in advance, such as a file download. If, in addition,
3841 @var{recursive?} is true, then that fixed output may be an executable
3842 file or a directory and @var{hash} must be the hash of an archive
3843 containing this output.
3845 When @var{references-graphs} is true, it must be a list of file
3846 name/store path pairs. In that case, the reference graph of each store
3847 path is exported in the build environment in the corresponding file, in
3848 a simple text format.
3850 When @var{allowed-references} is true, it must be a list of store items
3851 or outputs that the derivation's output may refer to. Likewise,
3852 @var{disallowed-references}, if true, must be a list of things the
3853 outputs may @emph{not} refer to.
3855 When @var{leaked-env-vars} is true, it must be a list of strings
3856 denoting environment variables that are allowed to ``leak'' from the
3857 daemon's environment to the build environment. This is only applicable
3858 to fixed-output derivations---i.e., when @var{hash} is true. The main
3859 use is to allow variables such as @code{http_proxy} to be passed to
3860 derivations that download files.
3862 When @var{local-build?} is true, declare that the derivation is not a
3863 good candidate for offloading and should rather be built locally
3864 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3865 where the costs of data transfers would outweigh the benefits.
3867 When @var{substitutable?} is false, declare that substitutes of the
3868 derivation's output should not be used (@pxref{Substitutes}). This is
3869 useful, for instance, when building packages that capture details of the
3870 host CPU instruction set.
3874 Here's an example with a shell script as its builder, assuming
3875 @var{store} is an open connection to the daemon, and @var{bash} points
3876 to a Bash executable in the store:
3879 (use-modules (guix utils)
3883 (let ((builder ; add the Bash script to the store
3884 (add-text-to-store store "my-builder.sh"
3885 "echo hello world > $out\n" '())))
3886 (derivation store "foo"
3887 bash `("-e" ,builder)
3888 #:inputs `((,bash) (,builder))
3889 #:env-vars '(("HOME" . "/homeless"))))
3890 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3893 As can be guessed, this primitive is cumbersome to use directly. A
3894 better approach is to write build scripts in Scheme, of course! The
3895 best course of action for that is to write the build code as a
3896 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3897 information, @pxref{G-Expressions}.
3899 Once upon a time, @code{gexp->derivation} did not exist and constructing
3900 derivations with build code written in Scheme was achieved with
3901 @code{build-expression->derivation}, documented below. This procedure
3902 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3904 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3905 @var{name} @var{exp} @
3906 [#:system (%current-system)] [#:inputs '()] @
3907 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3908 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3909 [#:references-graphs #f] [#:allowed-references #f] @
3910 [#:disallowed-references #f] @
3911 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3912 Return a derivation that executes Scheme expression @var{exp} as a
3913 builder for derivation @var{name}. @var{inputs} must be a list of
3914 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3915 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3916 modules from the current search path to be copied in the store,
3917 compiled, and made available in the load path during the execution of
3918 @var{exp}---e.g., @code{((guix build utils) (guix build
3919 gnu-build-system))}.
3921 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3922 to a list of output/path pairs, and where @code{%build-inputs} is bound
3923 to a list of string/output-path pairs made from @var{inputs}.
3924 Optionally, @var{env-vars} is a list of string pairs specifying the name
3925 and value of environment variables visible to the builder. The builder
3926 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3927 @var{exp} returns @code{#f}, the build is considered to have failed.
3929 @var{exp} is built using @var{guile-for-build} (a derivation). When
3930 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3931 @code{%guile-for-build} fluid is used instead.
3933 See the @code{derivation} procedure for the meaning of
3934 @var{references-graphs}, @var{allowed-references},
3935 @var{disallowed-references}, @var{local-build?}, and
3936 @var{substitutable?}.
3940 Here's an example of a single-output derivation that creates a directory
3941 containing one file:
3944 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3945 (mkdir out) ; create /gnu/store/@dots{}-goo
3946 (call-with-output-file (string-append out "/test")
3948 (display '(hello guix) p))))))
3949 (build-expression->derivation store "goo" builder))
3951 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3955 @node The Store Monad
3956 @section The Store Monad
3960 The procedures that operate on the store described in the previous
3961 sections all take an open connection to the build daemon as their first
3962 argument. Although the underlying model is functional, they either have
3963 side effects or depend on the current state of the store.
3965 The former is inconvenient: the connection to the build daemon has to be
3966 carried around in all those functions, making it impossible to compose
3967 functions that do not take that parameter with functions that do. The
3968 latter can be problematic: since store operations have side effects
3969 and/or depend on external state, they have to be properly sequenced.
3971 @cindex monadic values
3972 @cindex monadic functions
3973 This is where the @code{(guix monads)} module comes in. This module
3974 provides a framework for working with @dfn{monads}, and a particularly
3975 useful monad for our uses, the @dfn{store monad}. Monads are a
3976 construct that allows two things: associating ``context'' with values
3977 (in our case, the context is the store), and building sequences of
3978 computations (here computations include accesses to the store). Values
3979 in a monad---values that carry this additional context---are called
3980 @dfn{monadic values}; procedures that return such values are called
3981 @dfn{monadic procedures}.
3983 Consider this ``normal'' procedure:
3986 (define (sh-symlink store)
3987 ;; Return a derivation that symlinks the 'bash' executable.
3988 (let* ((drv (package-derivation store bash))
3989 (out (derivation->output-path drv))
3990 (sh (string-append out "/bin/bash")))
3991 (build-expression->derivation store "sh"
3992 `(symlink ,sh %output))))
3995 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3996 as a monadic function:
3999 (define (sh-symlink)
4000 ;; Same, but return a monadic value.
4001 (mlet %store-monad ((drv (package->derivation bash)))
4002 (gexp->derivation "sh"
4003 #~(symlink (string-append #$drv "/bin/bash")
4007 There are several things to note in the second version: the @code{store}
4008 parameter is now implicit and is ``threaded'' in the calls to the
4009 @code{package->derivation} and @code{gexp->derivation} monadic
4010 procedures, and the monadic value returned by @code{package->derivation}
4011 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4013 As it turns out, the call to @code{package->derivation} can even be
4014 omitted since it will take place implicitly, as we will see later
4015 (@pxref{G-Expressions}):
4018 (define (sh-symlink)
4019 (gexp->derivation "sh"
4020 #~(symlink (string-append #$bash "/bin/bash")
4025 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4026 @c for the funny quote.
4027 Calling the monadic @code{sh-symlink} has no effect. As someone once
4028 said, ``you exit a monad like you exit a building on fire: by running''.
4029 So, to exit the monad and get the desired effect, one must use
4030 @code{run-with-store}:
4033 (run-with-store (open-connection) (sh-symlink))
4034 @result{} /gnu/store/...-sh-symlink
4037 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4038 new ``meta-commands'' to make it easier to deal with monadic procedures:
4039 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4040 to ``run'' a single monadic value through the store:
4043 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4044 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4047 The latter enters a recursive REPL, where all the return values are
4048 automatically run through the store:
4051 scheme@@(guile-user)> ,enter-store-monad
4052 store-monad@@(guile-user) [1]> (package->derivation hello)
4053 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4054 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4055 $3 = "/gnu/store/@dots{}-foo"
4056 store-monad@@(guile-user) [1]> ,q
4057 scheme@@(guile-user)>
4061 Note that non-monadic values cannot be returned in the
4062 @code{store-monad} REPL.
4064 The main syntactic forms to deal with monads in general are provided by
4065 the @code{(guix monads)} module and are described below.
4067 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4068 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4072 @deffn {Scheme Syntax} return @var{val}
4073 Return a monadic value that encapsulates @var{val}.
4076 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4077 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4078 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4079 referred to as ``bind'', but that name denotes an unrelated procedure in
4080 Guile. Thus we use this somewhat cryptic symbol inherited from the
4081 Haskell language.}. There can be one @var{mproc} or several of them, as
4086 (with-monad %state-monad
4088 (lambda (x) (return (+ 1 x)))
4089 (lambda (x) (return (* 2 x)))))
4093 @result{} some-state
4097 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4099 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4101 Bind the variables @var{var} to the monadic values @var{mval} in
4102 @var{body}, which is a sequence of expressions. As with the bind
4103 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4104 value ``contained'' in @var{mval} and making @var{var} refer to that
4105 raw, non-monadic value within the scope of the @var{body}. The form
4106 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4107 @var{val}, as per @code{let}. The binding operations occur in sequence
4108 from left to right. The last expression of @var{body} must be a monadic
4109 expression, and its result will become the result of the @code{mlet} or
4110 @code{mlet*} when run in the @var{monad}.
4112 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4113 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4116 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4117 Bind @var{mexp} and the following monadic expressions in sequence,
4118 returning the result of the last expression. Every expression in the
4119 sequence must be a monadic expression.
4121 This is akin to @code{mlet}, except that the return values of the
4122 monadic expressions are ignored. In that sense, it is analogous to
4123 @code{begin}, but applied to monadic expressions.
4126 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4127 When @var{condition} is true, evaluate the sequence of monadic
4128 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4129 @var{condition} is false, return @code{*unspecified*} in the current
4130 monad. Every expression in the sequence must be a monadic expression.
4133 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4134 When @var{condition} is false, evaluate the sequence of monadic
4135 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4136 @var{condition} is true, return @code{*unspecified*} in the current
4137 monad. Every expression in the sequence must be a monadic expression.
4141 The @code{(guix monads)} module provides the @dfn{state monad}, which
4142 allows an additional value---the state---to be @emph{threaded} through
4143 monadic procedure calls.
4145 @defvr {Scheme Variable} %state-monad
4146 The state monad. Procedures in the state monad can access and change
4147 the state that is threaded.
4149 Consider the example below. The @code{square} procedure returns a value
4150 in the state monad. It returns the square of its argument, but also
4151 increments the current state value:
4155 (mlet %state-monad ((count (current-state)))
4156 (mbegin %state-monad
4157 (set-current-state (+ 1 count))
4160 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4165 When ``run'' through @var{%state-monad}, we obtain that additional state
4166 value, which is the number of @code{square} calls.
4169 @deffn {Monadic Procedure} current-state
4170 Return the current state as a monadic value.
4173 @deffn {Monadic Procedure} set-current-state @var{value}
4174 Set the current state to @var{value} and return the previous state as a
4178 @deffn {Monadic Procedure} state-push @var{value}
4179 Push @var{value} to the current state, which is assumed to be a list,
4180 and return the previous state as a monadic value.
4183 @deffn {Monadic Procedure} state-pop
4184 Pop a value from the current state and return it as a monadic value.
4185 The state is assumed to be a list.
4188 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4189 Run monadic value @var{mval} starting with @var{state} as the initial
4190 state. Return two values: the resulting value, and the resulting state.
4193 The main interface to the store monad, provided by the @code{(guix
4194 store)} module, is as follows.
4196 @defvr {Scheme Variable} %store-monad
4197 The store monad---an alias for @var{%state-monad}.
4199 Values in the store monad encapsulate accesses to the store. When its
4200 effect is needed, a value of the store monad must be ``evaluated'' by
4201 passing it to the @code{run-with-store} procedure (see below.)
4204 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4205 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4206 open store connection.
4209 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4210 Return as a monadic value the absolute file name in the store of the file
4211 containing @var{text}, a string. @var{references} is a list of store items that the
4212 resulting text file refers to; it defaults to the empty list.
4215 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4216 [#:recursive? #t] [#:select? (const #t)]
4217 Return the name of @var{file} once interned in the store. Use
4218 @var{name} as its store name, or the basename of @var{file} if
4219 @var{name} is omitted.
4221 When @var{recursive?} is true, the contents of @var{file} are added
4222 recursively; if @var{file} designates a flat file and @var{recursive?}
4223 is true, its contents are added, and its permission bits are kept.
4225 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4226 @var{stat})} for each directory entry, where @var{file} is the entry's
4227 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4228 entries for which @var{select?} does not return true.
4230 The example below adds a file to the store, under two different names:
4233 (run-with-store (open-connection)
4234 (mlet %store-monad ((a (interned-file "README"))
4235 (b (interned-file "README" "LEGU-MIN")))
4236 (return (list a b))))
4238 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4243 The @code{(guix packages)} module exports the following package-related
4246 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4247 [#:system (%current-system)] [#:target #f] @
4250 value in the absolute file name of @var{file} within the @var{output}
4251 directory of @var{package}. When @var{file} is omitted, return the name
4252 of the @var{output} directory of @var{package}. When @var{target} is
4253 true, use it as a cross-compilation target triplet.
4256 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4257 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4258 @var{target} [@var{system}]
4259 Monadic version of @code{package-derivation} and
4260 @code{package-cross-derivation} (@pxref{Defining Packages}).
4265 @section G-Expressions
4267 @cindex G-expression
4268 @cindex build code quoting
4269 So we have ``derivations'', which represent a sequence of build actions
4270 to be performed to produce an item in the store (@pxref{Derivations}).
4271 These build actions are performed when asking the daemon to actually
4272 build the derivations; they are run by the daemon in a container
4273 (@pxref{Invoking guix-daemon}).
4275 @cindex strata of code
4276 It should come as no surprise that we like to write these build actions
4277 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4278 code@footnote{The term @dfn{stratum} in this context was coined by
4279 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4280 Kiselyov, who has written insightful
4281 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4282 on this topic}, refers to this kind of code generation as
4283 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4284 to the daemon, etc.---and the ``build code''---code that actually
4285 performs build actions, such as making directories, invoking
4286 @command{make}, etc.
4288 To describe a derivation and its build actions, one typically needs to
4289 embed build code inside host code. It boils down to manipulating build
4290 code as data, and the homoiconicity of Scheme---code has a direct
4291 representation as data---comes in handy for that. But we need more than
4292 the normal @code{quasiquote} mechanism in Scheme to construct build
4295 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4296 S-expressions adapted to build expressions. G-expressions, or
4297 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4298 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4299 @code{#$}, and @code{#$@@}), which are comparable to
4300 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4301 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4302 GNU Guile Reference Manual}). However, there are major differences:
4306 Gexps are meant to be written to a file and run or manipulated by other
4310 When a high-level object such as a package or derivation is unquoted
4311 inside a gexp, the result is as if its output file name had been
4315 Gexps carry information about the packages or derivations they refer to,
4316 and these dependencies are automatically added as inputs to the build
4317 processes that use them.
4320 @cindex lowering, of high-level objects in gexps
4321 This mechanism is not limited to package and derivation
4322 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4323 derivations or files in the store can be defined,
4324 such that these objects can also be inserted
4325 into gexps. For example, a useful type of high-level objects that can be
4326 inserted in a gexp is ``file-like objects'', which make it easy to
4327 add files to the store and to refer to them in
4328 derivations and such (see @code{local-file} and @code{plain-file}
4331 To illustrate the idea, here is an example of a gexp:
4338 (symlink (string-append #$coreutils "/bin/ls")
4342 This gexp can be passed to @code{gexp->derivation}; we obtain a
4343 derivation that builds a directory containing exactly one symlink to
4344 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4347 (gexp->derivation "the-thing" build-exp)
4350 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4351 substituted to the reference to the @var{coreutils} package in the
4352 actual build code, and @var{coreutils} is automatically made an input to
4353 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4354 output)}) is replaced by a string containing the directory name of the
4355 output of the derivation.
4357 @cindex cross compilation
4358 In a cross-compilation context, it is useful to distinguish between
4359 references to the @emph{native} build of a package---that can run on the
4360 host---versus references to cross builds of a package. To that end, the
4361 @code{#+} plays the same role as @code{#$}, but is a reference to a
4362 native package build:
4365 (gexp->derivation "vi"
4368 (system* (string-append #+coreutils "/bin/ln")
4370 (string-append #$emacs "/bin/emacs")
4371 (string-append #$output "/bin/vi")))
4372 #:target "mips64el-linux-gnu")
4376 In the example above, the native build of @var{coreutils} is used, so
4377 that @command{ln} can actually run on the host; but then the
4378 cross-compiled build of @var{emacs} is referenced.
4380 @cindex imported modules, for gexps
4381 @findex with-imported-modules
4382 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4383 able to use certain Guile modules from the ``host environment'' in the
4384 gexp, so those modules should be imported in the ``build environment''.
4385 The @code{with-imported-modules} form allows you to express that:
4388 (let ((build (with-imported-modules '((guix build utils))
4390 (use-modules (guix build utils))
4391 (mkdir-p (string-append #$output "/bin"))))))
4392 (gexp->derivation "empty-dir"
4395 (display "success!\n")
4400 In this example, the @code{(guix build utils)} module is automatically
4401 pulled into the isolated build environment of our gexp, such that
4402 @code{(use-modules (guix build utils))} works as expected.
4404 @cindex module closure
4405 @findex source-module-closure
4406 Usually you want the @emph{closure} of the module to be imported---i.e.,
4407 the module itself and all the modules it depends on---rather than just
4408 the module; failing to do that, attempts to use the module will fail
4409 because of missing dependent modules. The @code{source-module-closure}
4410 procedure computes the closure of a module by looking at its source file
4411 headers, which comes in handy in this case:
4414 (use-modules (guix modules)) ;for 'source-module-closure'
4416 (with-imported-modules (source-module-closure
4417 '((guix build utils)
4419 (gexp->derivation "something-with-vms"
4421 (use-modules (guix build utils)
4426 The syntactic form to construct gexps is summarized below.
4428 @deffn {Scheme Syntax} #~@var{exp}
4429 @deffnx {Scheme Syntax} (gexp @var{exp})
4430 Return a G-expression containing @var{exp}. @var{exp} may contain one
4431 or more of the following forms:
4435 @itemx (ungexp @var{obj})
4436 Introduce a reference to @var{obj}. @var{obj} may have one of the
4437 supported types, for example a package or a
4438 derivation, in which case the @code{ungexp} form is replaced by its
4439 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4441 If @var{obj} is a list, it is traversed and references to supported
4442 objects are substituted similarly.
4444 If @var{obj} is another gexp, its contents are inserted and its
4445 dependencies are added to those of the containing gexp.
4447 If @var{obj} is another kind of object, it is inserted as is.
4449 @item #$@var{obj}:@var{output}
4450 @itemx (ungexp @var{obj} @var{output})
4451 This is like the form above, but referring explicitly to the
4452 @var{output} of @var{obj}---this is useful when @var{obj} produces
4453 multiple outputs (@pxref{Packages with Multiple Outputs}).
4456 @itemx #+@var{obj}:output
4457 @itemx (ungexp-native @var{obj})
4458 @itemx (ungexp-native @var{obj} @var{output})
4459 Same as @code{ungexp}, but produces a reference to the @emph{native}
4460 build of @var{obj} when used in a cross compilation context.
4462 @item #$output[:@var{output}]
4463 @itemx (ungexp output [@var{output}])
4464 Insert a reference to derivation output @var{output}, or to the main
4465 output when @var{output} is omitted.
4467 This only makes sense for gexps passed to @code{gexp->derivation}.
4470 @itemx (ungexp-splicing @var{lst})
4471 Like the above, but splices the contents of @var{lst} inside the
4475 @itemx (ungexp-native-splicing @var{lst})
4476 Like the above, but refers to native builds of the objects listed in
4481 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4482 of the @code{gexp?} type (see below.)
4485 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4486 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4487 in their execution environment.
4489 Each item in @var{modules} can be the name of a module, such as
4490 @code{(guix build utils)}, or it can be a module name, followed by an
4491 arrow, followed by a file-like object:
4494 `((guix build utils)
4496 ((guix config) => ,(scheme-file "config.scm"
4497 #~(define-module @dots{}))))
4501 In the example above, the first two modules are taken from the search
4502 path, and the last one is created from the given file-like object.
4504 This form has @emph{lexical} scope: it has an effect on the gexps
4505 directly defined in @var{body}@dots{}, but not on those defined, say, in
4506 procedures called from @var{body}@dots{}.
4509 @deffn {Scheme Procedure} gexp? @var{obj}
4510 Return @code{#t} if @var{obj} is a G-expression.
4513 G-expressions are meant to be written to disk, either as code building
4514 some derivation, or as plain files in the store. The monadic procedures
4515 below allow you to do that (@pxref{The Store Monad}, for more
4516 information about monads.)
4518 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4519 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4520 [#:hash #f] [#:hash-algo #f] @
4521 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4522 [#:module-path @var{%load-path}] @
4523 [#:references-graphs #f] [#:allowed-references #f] @
4524 [#:disallowed-references #f] @
4525 [#:leaked-env-vars #f] @
4526 [#:script-name (string-append @var{name} "-builder")] @
4527 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4528 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4529 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4530 stored in a file called @var{script-name}. When @var{target} is true,
4531 it is used as the cross-compilation target triplet for packages referred
4534 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4536 make @var{modules} available in the evaluation context of @var{exp};
4537 @var{modules} is a list of names of Guile modules searched in
4538 @var{module-path} to be copied in the store, compiled, and made available in
4539 the load path during the execution of @var{exp}---e.g., @code{((guix
4540 build utils) (guix build gnu-build-system))}.
4542 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4545 When @var{references-graphs} is true, it must be a list of tuples of one of the
4549 (@var{file-name} @var{package})
4550 (@var{file-name} @var{package} @var{output})
4551 (@var{file-name} @var{derivation})
4552 (@var{file-name} @var{derivation} @var{output})
4553 (@var{file-name} @var{store-item})
4556 The right-hand-side of each element of @var{references-graphs} is automatically made
4557 an input of the build process of @var{exp}. In the build environment, each
4558 @var{file-name} contains the reference graph of the corresponding item, in a simple
4561 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4562 In the latter case, the list denotes store items that the result is allowed to
4563 refer to. Any reference to another store item will lead to a build error.
4564 Similarly for @var{disallowed-references}, which can list items that must not be
4565 referenced by the outputs.
4567 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4570 @cindex file-like objects
4571 The @code{local-file}, @code{plain-file}, @code{computed-file},
4572 @code{program-file}, and @code{scheme-file} procedures below return
4573 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4574 these objects lead to a file in the store. Consider this G-expression:
4577 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4578 #$(local-file "/tmp/my-nscd.conf"))
4581 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4582 to the store. Once expanded, for instance @i{via}
4583 @code{gexp->derivation}, the G-expression refers to that copy under
4584 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4585 does not have any effect on what the G-expression does.
4586 @code{plain-file} can be used similarly; it differs in that the file
4587 content is directly passed as a string.
4589 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4590 [#:recursive? #f] [#:select? (const #t)]
4591 Return an object representing local file @var{file} to add to the store; this
4592 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4593 up relative to the source file where this form appears. @var{file} will be added to
4594 the store under @var{name}--by default the base name of @var{file}.
4596 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4597 designates a flat file and @var{recursive?} is true, its contents are added, and its
4598 permission bits are kept.
4600 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4601 @var{stat})} for each directory entry, where @var{file} is the entry's
4602 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4603 entries for which @var{select?} does not return true.
4605 This is the declarative counterpart of the @code{interned-file} monadic
4606 procedure (@pxref{The Store Monad, @code{interned-file}}).
4609 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4610 Return an object representing a text file called @var{name} with the given
4611 @var{content} (a string) to be added to the store.
4613 This is the declarative counterpart of @code{text-file}.
4616 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4617 [#:options '(#:local-build? #t)]
4618 Return an object representing the store item @var{name}, a file or
4619 directory computed by @var{gexp}. @var{options}
4620 is a list of additional arguments to pass to @code{gexp->derivation}.
4622 This is the declarative counterpart of @code{gexp->derivation}.
4625 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4626 Return an executable script @var{name} that runs @var{exp} using
4627 @var{guile}, with @var{exp}'s imported modules in its search path.
4629 The example below builds a script that simply invokes the @command{ls}
4633 (use-modules (guix gexp) (gnu packages base))
4635 (gexp->script "list-files"
4636 #~(execl #$(file-append coreutils "/bin/ls")
4640 When ``running'' it through the store (@pxref{The Store Monad,
4641 @code{run-with-store}}), we obtain a derivation that produces an
4642 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4645 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4647 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4651 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4653 Return an object representing the executable store item @var{name} that
4654 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4657 This is the declarative counterpart of @code{gexp->script}.
4660 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4661 [#:set-load-path? #t]
4662 Return a derivation that builds a file @var{name} containing @var{exp}.
4663 When @var{set-load-path?} is true, emit code in the resulting file to
4664 set @code{%load-path} and @code{%load-compiled-path} to honor
4665 @var{exp}'s imported modules.
4667 The resulting file holds references to all the dependencies of @var{exp}
4668 or a subset thereof.
4671 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4672 Return an object representing the Scheme file @var{name} that contains
4675 This is the declarative counterpart of @code{gexp->file}.
4678 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4679 Return as a monadic value a derivation that builds a text file
4680 containing all of @var{text}. @var{text} may list, in addition to
4681 strings, objects of any type that can be used in a gexp: packages,
4682 derivations, local file objects, etc. The resulting store file holds
4683 references to all these.
4685 This variant should be preferred over @code{text-file} anytime the file
4686 to create will reference items from the store. This is typically the
4687 case when building a configuration file that embeds store file names,
4691 (define (profile.sh)
4692 ;; Return the name of a shell script in the store that
4693 ;; initializes the 'PATH' environment variable.
4694 (text-file* "profile.sh"
4695 "export PATH=" coreutils "/bin:"
4696 grep "/bin:" sed "/bin\n"))
4699 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4700 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4701 preventing them from being garbage-collected during its lifetime.
4704 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4705 Return an object representing store file @var{name} containing
4706 @var{text}. @var{text} is a sequence of strings and file-like objects,
4710 (mixed-text-file "profile"
4711 "export PATH=" coreutils "/bin:" grep "/bin")
4714 This is the declarative counterpart of @code{text-file*}.
4717 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4718 Return a file-like object that expands to the concatenation of @var{obj}
4719 and @var{suffix}, where @var{obj} is a lowerable object and each
4720 @var{suffix} is a string.
4722 As an example, consider this gexp:
4725 (gexp->script "run-uname"
4726 #~(system* #$(file-append coreutils
4730 The same effect could be achieved with:
4733 (gexp->script "run-uname"
4734 #~(system* (string-append #$coreutils
4738 There is one difference though: in the @code{file-append} case, the
4739 resulting script contains the absolute file name as a string, whereas in
4740 the second case, the resulting script contains a @code{(string-append
4741 @dots{})} expression to construct the file name @emph{at run time}.
4745 Of course, in addition to gexps embedded in ``host'' code, there are
4746 also modules containing build tools. To make it clear that they are
4747 meant to be used in the build stratum, these modules are kept in the
4748 @code{(guix build @dots{})} name space.
4750 @cindex lowering, of high-level objects in gexps
4751 Internally, high-level objects are @dfn{lowered}, using their compiler,
4752 to either derivations or store items. For instance, lowering a package
4753 yields a derivation, and lowering a @code{plain-file} yields a store
4754 item. This is achieved using the @code{lower-object} monadic procedure.
4756 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4758 Return as a value in @var{%store-monad} the derivation or store item
4759 corresponding to @var{obj} for @var{system}, cross-compiling for
4760 @var{target} if @var{target} is true. @var{obj} must be an object that
4761 has an associated gexp compiler, such as a @code{<package>}.
4765 @c *********************************************************************
4769 This section describes Guix command-line utilities. Some of them are
4770 primarily targeted at developers and users who write new package
4771 definitions, while others are more generally useful. They complement
4772 the Scheme programming interface of Guix in a convenient way.
4775 * Invoking guix build:: Building packages from the command line.
4776 * Invoking guix edit:: Editing package definitions.
4777 * Invoking guix download:: Downloading a file and printing its hash.
4778 * Invoking guix hash:: Computing the cryptographic hash of a file.
4779 * Invoking guix import:: Importing package definitions.
4780 * Invoking guix refresh:: Updating package definitions.
4781 * Invoking guix lint:: Finding errors in package definitions.
4782 * Invoking guix size:: Profiling disk usage.
4783 * Invoking guix graph:: Visualizing the graph of packages.
4784 * Invoking guix environment:: Setting up development environments.
4785 * Invoking guix publish:: Sharing substitutes.
4786 * Invoking guix challenge:: Challenging substitute servers.
4787 * Invoking guix copy:: Copying to and from a remote store.
4788 * Invoking guix container:: Process isolation.
4791 @node Invoking guix build
4792 @section Invoking @command{guix build}
4794 @cindex package building
4795 @cindex @command{guix build}
4796 The @command{guix build} command builds packages or derivations and
4797 their dependencies, and prints the resulting store paths. Note that it
4798 does not modify the user's profile---this is the job of the
4799 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4800 it is mainly useful for distribution developers.
4802 The general syntax is:
4805 guix build @var{options} @var{package-or-derivation}@dots{}
4808 As an example, the following command builds the latest versions of Emacs
4809 and of Guile, displays their build logs, and finally displays the
4810 resulting directories:
4813 guix build emacs guile
4816 Similarly, the following command builds all the available packages:
4819 guix build --quiet --keep-going \
4820 `guix package -A | cut -f1,2 --output-delimiter=@@`
4823 @var{package-or-derivation} may be either the name of a package found in
4824 the software distribution such as @code{coreutils} or
4825 @code{coreutils@@8.20}, or a derivation such as
4826 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4827 package with the corresponding name (and optionally version) is searched
4828 for among the GNU distribution modules (@pxref{Package Modules}).
4830 Alternatively, the @code{--expression} option may be used to specify a
4831 Scheme expression that evaluates to a package; this is useful when
4832 disambiguating among several same-named packages or package variants is
4835 There may be zero or more @var{options}. The available options are
4836 described in the subsections below.
4839 * Common Build Options:: Build options for most commands.
4840 * Package Transformation Options:: Creating variants of packages.
4841 * Additional Build Options:: Options specific to 'guix build'.
4842 * Debugging Build Failures:: Real life packaging experience
4845 @node Common Build Options
4846 @subsection Common Build Options
4848 A number of options that control the build process are common to
4849 @command{guix build} and other commands that can spawn builds, such as
4850 @command{guix package} or @command{guix archive}. These are the
4855 @item --load-path=@var{directory}
4856 @itemx -L @var{directory}
4857 Add @var{directory} to the front of the package module search path
4858 (@pxref{Package Modules}).
4860 This allows users to define their own packages and make them visible to
4861 the command-line tools.
4865 Keep the build tree of failed builds. Thus, if a build fails, its build
4866 tree is kept under @file{/tmp}, in a directory whose name is shown at
4867 the end of the build log. This is useful when debugging build issues.
4868 @xref{Debugging Build Failures}, for tips and tricks on how to debug
4873 Keep going when some of the derivations fail to build; return only once
4874 all the builds have either completed or failed.
4876 The default behavior is to stop as soon as one of the specified
4877 derivations has failed.
4881 Do not build the derivations.
4884 When substituting a pre-built binary fails, fall back to building
4887 @item --substitute-urls=@var{urls}
4888 @anchor{client-substitute-urls}
4889 Consider @var{urls} the whitespace-separated list of substitute source
4890 URLs, overriding the default list of URLs of @command{guix-daemon}
4891 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4893 This means that substitutes may be downloaded from @var{urls}, provided
4894 they are signed by a key authorized by the system administrator
4895 (@pxref{Substitutes}).
4897 When @var{urls} is the empty string, substitutes are effectively
4900 @item --no-substitutes
4901 Do not use substitutes for build products. That is, always build things
4902 locally instead of allowing downloads of pre-built binaries
4903 (@pxref{Substitutes}).
4906 Do not ``graft'' packages. In practice, this means that package updates
4907 available as grafts are not applied. @xref{Security Updates}, for more
4908 information on grafts.
4910 @item --rounds=@var{n}
4911 Build each derivation @var{n} times in a row, and raise an error if
4912 consecutive build results are not bit-for-bit identical.
4914 This is a useful way to detect non-deterministic builds processes.
4915 Non-deterministic build processes are a problem because they make it
4916 practically impossible for users to @emph{verify} whether third-party
4917 binaries are genuine. @xref{Invoking guix challenge}, for more.
4919 Note that, currently, the differing build results are not kept around,
4920 so you will have to manually investigate in case of an error---e.g., by
4921 stashing one of the build results with @code{guix archive --export}
4922 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4925 @item --no-build-hook
4926 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4927 (@pxref{Daemon Offload Setup}). That is, always build things locally
4928 instead of offloading builds to remote machines.
4930 @item --max-silent-time=@var{seconds}
4931 When the build or substitution process remains silent for more than
4932 @var{seconds}, terminate it and report a build failure.
4934 @item --timeout=@var{seconds}
4935 Likewise, when the build or substitution process lasts for more than
4936 @var{seconds}, terminate it and report a build failure.
4938 By default there is no timeout. This behavior can be restored with
4941 @item --verbosity=@var{level}
4942 Use the given verbosity level. @var{level} must be an integer between 0
4943 and 5; higher means more verbose output. Setting a level of 4 or more
4944 may be helpful when debugging setup issues with the build daemon.
4946 @item --cores=@var{n}
4948 Allow the use of up to @var{n} CPU cores for the build. The special
4949 value @code{0} means to use as many CPU cores as available.
4951 @item --max-jobs=@var{n}
4953 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4954 guix-daemon, @code{--max-jobs}}, for details about this option and the
4955 equivalent @command{guix-daemon} option.
4959 Behind the scenes, @command{guix build} is essentially an interface to
4960 the @code{package-derivation} procedure of the @code{(guix packages)}
4961 module, and to the @code{build-derivations} procedure of the @code{(guix
4962 derivations)} module.
4964 In addition to options explicitly passed on the command line,
4965 @command{guix build} and other @command{guix} commands that support
4966 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4968 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4969 Users can define this variable to a list of command line options that
4970 will automatically be used by @command{guix build} and other
4971 @command{guix} commands that can perform builds, as in the example
4975 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4978 These options are parsed independently, and the result is appended to
4979 the parsed command-line options.
4983 @node Package Transformation Options
4984 @subsection Package Transformation Options
4986 @cindex package variants
4987 Another set of command-line options supported by @command{guix build}
4988 and also @command{guix package} are @dfn{package transformation
4989 options}. These are options that make it possible to define @dfn{package
4990 variants}---for instance, packages built from different source code.
4991 This is a convenient way to create customized packages on the fly
4992 without having to type in the definitions of package variants
4993 (@pxref{Defining Packages}).
4997 @item --with-source=@var{source}
4998 Use @var{source} as the source of the corresponding package.
4999 @var{source} must be a file name or a URL, as for @command{guix
5000 download} (@pxref{Invoking guix download}).
5002 The ``corresponding package'' is taken to be the one specified on the
5003 command line the name of which matches the base of @var{source}---e.g.,
5004 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
5005 package is @code{guile}. Likewise, the version string is inferred from
5006 @var{source}; in the previous example, it is @code{2.0.10}.
5008 This option allows users to try out versions of packages other than the
5009 one provided by the distribution. The example below downloads
5010 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5011 the @code{ed} package:
5014 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5017 As a developer, @code{--with-source} makes it easy to test release
5021 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5024 @dots{} or to build from a checkout in a pristine environment:
5027 $ git clone git://git.sv.gnu.org/guix.git
5028 $ guix build guix --with-source=./guix
5031 @item --with-input=@var{package}=@var{replacement}
5032 Replace dependency on @var{package} by a dependency on
5033 @var{replacement}. @var{package} must be a package name, and
5034 @var{replacement} must be a package specification such as @code{guile}
5035 or @code{guile@@1.8}.
5037 For instance, the following command builds Guix, but replaces its
5038 dependency on the current stable version of Guile with a dependency on
5039 the legacy version of Guile, @code{guile@@2.0}:
5042 guix build --with-input=guile=guile@@2.0 guix
5045 This is a recursive, deep replacement. So in this example, both
5046 @code{guix} and its dependency @code{guile-json} (which also depends on
5047 @code{guile}) get rebuilt against @code{guile@@2.0}.
5049 This is implemented using the @code{package-input-rewriting} Scheme
5050 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5052 @item --with-graft=@var{package}=@var{replacement}
5053 This is similar to @code{--with-input} but with an important difference:
5054 instead of rebuilding the whole dependency chain, @var{replacement} is
5055 built and then @dfn{grafted} onto the binaries that were initially
5056 referring to @var{package}. @xref{Security Updates}, for more
5057 information on grafts.
5059 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5060 and all its dependencies, replacing references to the version of GnuTLS
5061 they currently refer to:
5064 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5067 This has the advantage of being much faster than rebuilding everything.
5068 But there is a caveat: it works if and only if @var{package} and
5069 @var{replacement} are strictly compatible---for example, if they provide
5070 a library, the application binary interface (ABI) of those libraries
5071 must be compatible. If @var{replacement} is somehow incompatible with
5072 @var{package}, then the resulting package may be unusable. Use with
5077 @node Additional Build Options
5078 @subsection Additional Build Options
5080 The command-line options presented below are specific to @command{guix
5087 Build quietly, without displaying the build log. Upon completion, the
5088 build log is kept in @file{/var} (or similar) and can always be
5089 retrieved using the @option{--log-file} option.
5091 @item --file=@var{file}
5092 @itemx -f @var{file}
5094 Build the package or derivation that the code within @var{file}
5097 As an example, @var{file} might contain a package definition like this
5098 (@pxref{Defining Packages}):
5101 @verbatiminclude package-hello.scm
5104 @item --expression=@var{expr}
5105 @itemx -e @var{expr}
5106 Build the package or derivation @var{expr} evaluates to.
5108 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5109 guile-1.8)}, which unambiguously designates this specific variant of
5110 version 1.8 of Guile.
5112 Alternatively, @var{expr} may be a G-expression, in which case it is used
5113 as a build program passed to @code{gexp->derivation}
5114 (@pxref{G-Expressions}).
5116 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5117 (@pxref{The Store Monad}). The procedure must return a derivation as a
5118 monadic value, which is then passed through @code{run-with-store}.
5122 Build the source derivations of the packages, rather than the packages
5125 For instance, @code{guix build -S gcc} returns something like
5126 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5129 The returned source tarball is the result of applying any patches and
5130 code snippets specified in the package @code{origin} (@pxref{Defining
5134 Fetch and return the source of @var{package-or-derivation} and all their
5135 dependencies, recursively. This is a handy way to obtain a local copy
5136 of all the source code needed to build @var{packages}, allowing you to
5137 eventually build them even without network access. It is an extension
5138 of the @code{--source} option and can accept one of the following
5139 optional argument values:
5143 This value causes the @code{--sources} option to behave in the same way
5144 as the @code{--source} option.
5147 Build the source derivations of all packages, including any source that
5148 might be listed as @code{inputs}. This is the default value.
5151 $ guix build --sources tzdata
5152 The following derivations will be built:
5153 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5154 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5158 Build the source derivations of all packages, as well of all transitive
5159 inputs to the packages. This can be used e.g. to
5160 prefetch package source for later offline building.
5163 $ guix build --sources=transitive tzdata
5164 The following derivations will be built:
5165 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5166 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5167 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5168 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5169 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5170 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5176 @item --system=@var{system}
5177 @itemx -s @var{system}
5178 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5179 the system type of the build host.
5181 An example use of this is on Linux-based systems, which can emulate
5182 different personalities. For instance, passing
5183 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5184 to build packages in a complete 32-bit environment.
5186 @item --target=@var{triplet}
5187 @cindex cross-compilation
5188 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5189 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5190 configuration triplets,, autoconf, Autoconf}).
5192 @anchor{build-check}
5194 @cindex determinism, checking
5195 @cindex reproducibility, checking
5196 Rebuild @var{package-or-derivation}, which are already available in the
5197 store, and raise an error if the build results are not bit-for-bit
5200 This mechanism allows you to check whether previously installed
5201 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5202 of a package is deterministic. @xref{Invoking guix challenge}, for more
5203 background information and tools.
5205 When used in conjunction with @option{--keep-failed}, the differing
5206 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5207 This makes it easy to look for differences between the two results.
5210 @cindex repairing store items
5211 @cindex corruption, recovering from
5212 Attempt to repair the specified store items, if they are corrupt, by
5213 re-downloading or rebuilding them.
5215 This operation is not atomic and thus restricted to @code{root}.
5219 Return the derivation paths, not the output paths, of the given
5222 @item --root=@var{file}
5223 @itemx -r @var{file}
5224 Make @var{file} a symlink to the result, and register it as a garbage
5228 Return the build log file names or URLs for the given
5229 @var{package-or-derivation}, or raise an error if build logs are
5232 This works regardless of how packages or derivations are specified. For
5233 instance, the following invocations are equivalent:
5236 guix build --log-file `guix build -d guile`
5237 guix build --log-file `guix build guile`
5238 guix build --log-file guile
5239 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5242 If a log is unavailable locally, and unless @code{--no-substitutes} is
5243 passed, the command looks for a corresponding log on one of the
5244 substitute servers (as specified with @code{--substitute-urls}.)
5246 So for instance, imagine you want to see the build log of GDB on MIPS,
5247 but you are actually on an @code{x86_64} machine:
5250 $ guix build --log-file gdb -s mips64el-linux
5251 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5254 You can freely access a huge library of build logs!
5257 @node Debugging Build Failures
5258 @subsection Debugging Build Failures
5260 @cindex build failures, debugging
5261 When defining a new package (@pxref{Defining Packages}), you will
5262 probably find yourself spending some time debugging and tweaking the
5263 build until it succeeds. To do that, you need to operate the build
5264 commands yourself in an environment as close as possible to the one the
5267 To that end, the first thing to do is to use the @option{--keep-failed}
5268 or @option{-K} option of @command{guix build}, which will keep the
5269 failed build tree in @file{/tmp} or whatever directory you specified as
5270 @code{TMPDIR} (@pxref{Invoking guix build, @code{--keep-failed}}).
5272 From there on, you can @command{cd} to the failed build tree and source
5273 the @file{environment-variables} file, which contains all the
5274 environment variable definitions that were in place when the build
5275 failed. So let's say you're debugging a build failure in package
5276 @code{foo}; a typical session would look like this:
5280 @dots{} @i{build fails}
5281 $ cd /tmp/guix-build-foo.drv-0
5282 $ source ./environment-variables
5286 Now, you can invoke commands as if you were the daemon (almost) and
5287 troubleshoot your build process.
5289 Sometimes it happens that, for example, a package's tests pass when you
5290 run them manually but they fail when the daemon runs them. This can
5291 happen because the daemon runs builds in containers where, unlike in our
5292 environment above, network access is missing, @file{/bin/sh} does not
5293 exist, etc. (@pxref{Build Environment Setup}).
5295 In such cases, you may need to run inspect the build process from within
5296 a container similar to the one the build daemon creates:
5301 $ cd /tmp/guix-build-foo.drv-0
5302 $ guix environment -C foo --ad-hoc strace gdb
5303 [env]# source ./environment-variables
5307 Here, @command{guix environment -C} creates a container and spawns a new
5308 shell in it (@pxref{Invoking guix environment}). The @command{--ad-hoc
5309 strace gdb} part adds the @command{strace} and @command{gdb} commands to
5310 the container, which would may find handy while debugging.
5312 To get closer to a container like that used by the build daemon, we can
5313 remove @file{/bin/sh}:
5319 (Don't worry, this is harmless: this is all happening in the throw-away
5320 container created by @command{guix environment}.)
5322 The @command{strace} command is probably not in the search path, but we
5326 [env]# $GUIX_ENVIRONMENT/bin/strace -f -o log make check
5329 In this way, not only you will have reproduced the environment variables
5330 the daemon uses, you will also be running the build process in a container
5331 similar to the one the daemon uses.
5334 @node Invoking guix edit
5335 @section Invoking @command{guix edit}
5337 @cindex @command{guix edit}
5338 @cindex package definition, editing
5339 So many packages, so many source files! The @command{guix edit} command
5340 facilitates the life of users and packagers by pointing their editor at
5341 the source file containing the definition of the specified packages.
5345 guix edit gcc@@4.9 vim
5349 launches the program specified in the @code{VISUAL} or in the
5350 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5353 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5354 have created your own packages on @code{GUIX_PACKAGE_PATH}
5355 (@pxref{Defining Packages}), you will be able to edit the package
5356 recipes. Otherwise, you will be able to examine the read-only recipes
5357 for packages currently in the store.
5360 @node Invoking guix download
5361 @section Invoking @command{guix download}
5363 @cindex @command{guix download}
5364 @cindex downloading package sources
5365 When writing a package definition, developers typically need to download
5366 a source tarball, compute its SHA256 hash, and write that
5367 hash in the package definition (@pxref{Defining Packages}). The
5368 @command{guix download} tool helps with this task: it downloads a file
5369 from the given URI, adds it to the store, and prints both its file name
5370 in the store and its SHA256 hash.
5372 The fact that the downloaded file is added to the store saves bandwidth:
5373 when the developer eventually tries to build the newly defined package
5374 with @command{guix build}, the source tarball will not have to be
5375 downloaded again because it is already in the store. It is also a
5376 convenient way to temporarily stash files, which may be deleted
5377 eventually (@pxref{Invoking guix gc}).
5379 The @command{guix download} command supports the same URIs as used in
5380 package definitions. In particular, it supports @code{mirror://} URIs.
5381 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5382 Guile bindings for GnuTLS are available in the user's environment; when
5383 they are not available, an error is raised. @xref{Guile Preparations,
5384 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5385 GnuTLS-Guile}, for more information.
5387 @command{guix download} verifies HTTPS server certificates by loading
5388 the certificates of X.509 authorities from the directory pointed to by
5389 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5390 Certificates}), unless @option{--no-check-certificate} is used.
5392 The following options are available:
5395 @item --format=@var{fmt}
5397 Write the hash in the format specified by @var{fmt}. For more
5398 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5400 @item --no-check-certificate
5401 Do not validate the X.509 certificates of HTTPS servers.
5403 When using this option, you have @emph{absolutely no guarantee} that you
5404 are communicating with the authentic server responsible for the given
5405 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5407 @item --output=@var{file}
5408 @itemx -o @var{file}
5409 Save the downloaded file to @var{file} instead of adding it to the
5413 @node Invoking guix hash
5414 @section Invoking @command{guix hash}
5416 @cindex @command{guix hash}
5417 The @command{guix hash} command computes the SHA256 hash of a file.
5418 It is primarily a convenience tool for anyone contributing to the
5419 distribution: it computes the cryptographic hash of a file, which can be
5420 used in the definition of a package (@pxref{Defining Packages}).
5422 The general syntax is:
5425 guix hash @var{option} @var{file}
5428 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5429 hash of data read from standard input. @command{guix hash} has the
5434 @item --format=@var{fmt}
5436 Write the hash in the format specified by @var{fmt}.
5438 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5439 (@code{hex} and @code{hexadecimal} can be used as well).
5441 If the @option{--format} option is not specified, @command{guix hash}
5442 will output the hash in @code{nix-base32}. This representation is used
5443 in the definitions of packages.
5447 Compute the hash on @var{file} recursively.
5449 In this case, the hash is computed on an archive containing @var{file},
5450 including its children if it is a directory. Some of the metadata of
5451 @var{file} is part of the archive; for instance, when @var{file} is a
5452 regular file, the hash is different depending on whether @var{file} is
5453 executable or not. Metadata such as time stamps has no impact on the
5454 hash (@pxref{Invoking guix archive}).
5455 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5460 When combined with @option{--recursive}, exclude version control system
5461 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5464 As an example, here is how you would compute the hash of a Git checkout,
5465 which is useful when using the @code{git-fetch} method (@pxref{origin
5469 $ git clone http://example.org/foo.git
5475 @node Invoking guix import
5476 @section Invoking @command{guix import}
5478 @cindex importing packages
5479 @cindex package import
5480 @cindex package conversion
5481 @cindex Invoking @command{guix import}
5482 The @command{guix import} command is useful for people who would like to
5483 add a package to the distribution with as little work as
5484 possible---a legitimate demand. The command knows of a few
5485 repositories from which it can ``import'' package metadata. The result
5486 is a package definition, or a template thereof, in the format we know
5487 (@pxref{Defining Packages}).
5489 The general syntax is:
5492 guix import @var{importer} @var{options}@dots{}
5495 @var{importer} specifies the source from which to import package
5496 metadata, and @var{options} specifies a package identifier and other
5497 options specific to @var{importer}. Currently, the available
5502 Import metadata for the given GNU package. This provides a template
5503 for the latest version of that GNU package, including the hash of its
5504 source tarball, and its canonical synopsis and description.
5506 Additional information such as the package dependencies and its
5507 license needs to be figured out manually.
5509 For example, the following command returns a package definition for
5513 guix import gnu hello
5516 Specific command-line options are:
5519 @item --key-download=@var{policy}
5520 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5521 keys when verifying the package signature. @xref{Invoking guix
5522 refresh, @code{--key-download}}.
5527 Import metadata from the @uref{https://pypi.python.org/, Python Package
5528 Index}@footnote{This functionality requires Guile-JSON to be installed.
5529 @xref{Requirements}.}. Information is taken from the JSON-formatted
5530 description available at @code{pypi.python.org} and usually includes all
5531 the relevant information, including package dependencies. For maximum
5532 efficiency, it is recommended to install the @command{unzip} utility, so
5533 that the importer can unzip Python wheels and gather data from them.
5535 The command below imports metadata for the @code{itsdangerous} Python
5539 guix import pypi itsdangerous
5544 Import metadata from @uref{https://rubygems.org/,
5545 RubyGems}@footnote{This functionality requires Guile-JSON to be
5546 installed. @xref{Requirements}.}. Information is taken from the
5547 JSON-formatted description available at @code{rubygems.org} and includes
5548 most relevant information, including runtime dependencies. There are
5549 some caveats, however. The metadata doesn't distinguish between
5550 synopses and descriptions, so the same string is used for both fields.
5551 Additionally, the details of non-Ruby dependencies required to build
5552 native extensions is unavailable and left as an exercise to the
5555 The command below imports metadata for the @code{rails} Ruby package:
5558 guix import gem rails
5563 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5564 functionality requires Guile-JSON to be installed.
5565 @xref{Requirements}.}.
5566 Information is taken from the JSON-formatted metadata provided through
5567 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5568 relevant information, such as module dependencies. License information
5569 should be checked closely. If Perl is available in the store, then the
5570 @code{corelist} utility will be used to filter core modules out of the
5571 list of dependencies.
5573 The command command below imports metadata for the @code{Acme::Boolean}
5577 guix import cpan Acme::Boolean
5582 @cindex Bioconductor
5583 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5584 central repository for the @uref{http://r-project.org, GNU@tie{}R
5585 statistical and graphical environment}.
5587 Information is extracted from the @code{DESCRIPTION} file of the package.
5589 The command command below imports metadata for the @code{Cairo}
5593 guix import cran Cairo
5596 When @code{--recursive} is added, the importer will traverse the
5597 dependency graph of the given upstream package recursively and generate
5598 package expressions for all those packages that are not yet in Guix.
5600 When @code{--archive=bioconductor} is added, metadata is imported from
5601 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5602 packages for for the analysis and comprehension of high-throughput
5603 genomic data in bioinformatics.
5605 Information is extracted from the @code{DESCRIPTION} file of a package
5606 published on the web interface of the Bioconductor SVN repository.
5608 The command below imports metadata for the @code{GenomicRanges}
5612 guix import cran --archive=bioconductor GenomicRanges
5616 Import metadata from a local copy of the source of the
5617 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5618 relies on the @command{nix-instantiate} command of
5619 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5620 typically written in a mixture of Nix-language and Bash code. This
5621 command only imports the high-level package structure that is written in
5622 the Nix language. It normally includes all the basic fields of a
5625 When importing a GNU package, the synopsis and descriptions are replaced
5626 by their canonical upstream variant.
5628 Usually, you will first need to do:
5631 export NIX_REMOTE=daemon
5635 so that @command{nix-instantiate} does not try to open the Nix database.
5637 As an example, the command below imports the package definition of
5638 LibreOffice (more precisely, it imports the definition of the package
5639 bound to the @code{libreoffice} top-level attribute):
5642 guix import nix ~/path/to/nixpkgs libreoffice
5647 Import metadata from the Haskell community's central package archive
5648 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5649 Cabal files and includes all the relevant information, including package
5652 Specific command-line options are:
5657 Read a Cabal file from standard input.
5658 @item --no-test-dependencies
5660 Do not include dependencies required only by the test suites.
5661 @item --cabal-environment=@var{alist}
5662 @itemx -e @var{alist}
5663 @var{alist} is a Scheme alist defining the environment in which the
5664 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5665 @code{arch}, @code{impl} and a string representing the name of a flag.
5666 The value associated with a flag has to be either the symbol
5667 @code{true} or @code{false}. The value associated with other keys
5668 has to conform to the Cabal file format definition. The default value
5669 associated with the keys @code{os}, @code{arch} and @code{impl} is
5670 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5673 The command below imports metadata for the latest version of the
5674 @code{HTTP} Haskell package without including test dependencies and
5675 specifying the value of the flag @samp{network-uri} as @code{false}:
5678 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5681 A specific package version may optionally be specified by following the
5682 package name by an at-sign and a version number as in the following example:
5685 guix import hackage mtl@@2.1.3.1
5690 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5691 It takes a package name, looks up the package version included in a
5692 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5693 release and uses the @code{hackage} importer to retrieve its metadata.
5694 Note that it is up to you to select an LTS release compatible with the
5695 GHC compiler used by Guix.
5697 Specific command-line options are:
5700 @item --no-test-dependencies
5702 Do not include dependencies required only by the test suites.
5703 @item --lts-version=@var{version}
5704 @itemx -r @var{version}
5705 @var{version} is the desired LTS release version. If omitted the latest
5709 The command below imports metadata for the @code{HTTP} Haskell package
5710 included in the LTS Stackage release version 7.18:
5713 guix import stackage --lts-version=7.18 HTTP
5718 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5719 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5721 Specific command-line options are:
5724 @item --archive=@var{repo}
5725 @itemx -a @var{repo}
5726 @var{repo} identifies the archive repository from which to retrieve the
5727 information. Currently the supported repositories and their identifiers
5731 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5732 identifier. This is the default.
5734 Packages from @code{elpa.gnu.org} are signed with one of the keys
5735 contained in the GnuPG keyring at
5736 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5737 @code{emacs} package (@pxref{Package Installation, ELPA package
5738 signatures,, emacs, The GNU Emacs Manual}).
5741 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5742 @code{melpa-stable} identifier.
5745 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5752 Import metadata from the crates.io Rust package repository
5753 @uref{https://crates.io, crates.io}.
5756 The structure of the @command{guix import} code is modular. It would be
5757 useful to have more importers for other package formats, and your help
5758 is welcome here (@pxref{Contributing}).
5760 @node Invoking guix refresh
5761 @section Invoking @command{guix refresh}
5763 @cindex @command {guix refresh}
5764 The primary audience of the @command{guix refresh} command is developers
5765 of the GNU software distribution. By default, it reports any packages
5766 provided by the distribution that are outdated compared to the latest
5767 upstream version, like this:
5771 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5772 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5775 Alternately, one can specify packages to consider, in which case a
5776 warning is emitted for packages that lack an updater:
5779 $ guix refresh coreutils guile guile-ssh
5780 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5781 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5784 @command{guix refresh} browses the upstream repository of each package and determines
5785 the highest version number of the releases therein. The command
5786 knows how to update specific types of packages: GNU packages, ELPA
5787 packages, etc.---see the documentation for @option{--type} below. There
5788 are many packages, though, for which it lacks a method to determine
5789 whether a new upstream release is available. However, the mechanism is
5790 extensible, so feel free to get in touch with us to add a new method!
5792 When passed @code{--update}, it modifies distribution source files to
5793 update the version numbers and source tarball hashes of those package
5794 recipes (@pxref{Defining Packages}). This is achieved by downloading
5795 each package's latest source tarball and its associated OpenPGP
5796 signature, authenticating the downloaded tarball against its signature
5797 using @command{gpg}, and finally computing its hash. When the public
5798 key used to sign the tarball is missing from the user's keyring, an
5799 attempt is made to automatically retrieve it from a public key server;
5800 when this is successful, the key is added to the user's keyring; otherwise,
5801 @command{guix refresh} reports an error.
5803 The following options are supported:
5807 @item --expression=@var{expr}
5808 @itemx -e @var{expr}
5809 Consider the package @var{expr} evaluates to.
5811 This is useful to precisely refer to a package, as in this example:
5814 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5817 This command lists the dependents of the ``final'' libc (essentially all
5822 Update distribution source files (package recipes) in place. This is
5823 usually run from a checkout of the Guix source tree (@pxref{Running
5824 Guix Before It Is Installed}):
5827 $ ./pre-inst-env guix refresh -s non-core -u
5830 @xref{Defining Packages}, for more information on package definitions.
5832 @item --select=[@var{subset}]
5833 @itemx -s @var{subset}
5834 Select all the packages in @var{subset}, one of @code{core} or
5837 The @code{core} subset refers to all the packages at the core of the
5838 distribution---i.e., packages that are used to build ``everything
5839 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5840 changing one of these packages in the distribution entails a rebuild of
5841 all the others. Thus, such updates are an inconvenience to users in
5842 terms of build time or bandwidth used to achieve the upgrade.
5844 The @code{non-core} subset refers to the remaining packages. It is
5845 typically useful in cases where an update of the core packages would be
5848 @item --type=@var{updater}
5849 @itemx -t @var{updater}
5850 Select only packages handled by @var{updater} (may be a comma-separated
5851 list of updaters). Currently, @var{updater} may be one of:
5855 the updater for GNU packages;
5857 the updater for GNOME packages;
5859 the updater for KDE packages;
5861 the updater for X.org packages;
5863 the updater for packages hosted on kernel.org;
5865 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5867 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5869 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5871 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5873 the updater for @uref{https://pypi.python.org, PyPI} packages.
5875 the updater for @uref{https://rubygems.org, RubyGems} packages.
5877 the updater for @uref{https://github.com, GitHub} packages.
5879 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5881 the updater for @uref{https://www.stackage.org, Stackage} packages.
5883 the updater for @uref{https://crates.io, Crates} packages.
5886 For instance, the following command only checks for updates of Emacs
5887 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5890 $ guix refresh --type=elpa,cran
5891 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5892 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5897 In addition, @command{guix refresh} can be passed one or more package
5898 names, as in this example:
5901 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5905 The command above specifically updates the @code{emacs} and
5906 @code{idutils} packages. The @code{--select} option would have no
5907 effect in this case.
5909 When considering whether to upgrade a package, it is sometimes
5910 convenient to know which packages would be affected by the upgrade and
5911 should be checked for compatibility. For this the following option may
5912 be used when passing @command{guix refresh} one or more package names:
5916 @item --list-updaters
5918 List available updaters and exit (see @option{--type} above.)
5920 For each updater, display the fraction of packages it covers; at the
5921 end, display the fraction of packages covered by all these updaters.
5923 @item --list-dependent
5925 List top-level dependent packages that would need to be rebuilt as a
5926 result of upgrading one or more packages.
5928 @xref{Invoking guix graph, the @code{reverse-package} type of
5929 @command{guix graph}}, for information on how to visualize the list of
5930 dependents of a package.
5934 Be aware that the @code{--list-dependent} option only
5935 @emph{approximates} the rebuilds that would be required as a result of
5936 an upgrade. More rebuilds might be required under some circumstances.
5939 $ guix refresh --list-dependent flex
5940 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5941 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
5944 The command above lists a set of packages that could be built to check
5945 for compatibility with an upgraded @code{flex} package.
5947 The following options can be used to customize GnuPG operation:
5951 @item --gpg=@var{command}
5952 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5953 for in @code{$PATH}.
5955 @item --key-download=@var{policy}
5956 Handle missing OpenPGP keys according to @var{policy}, which may be one
5961 Always download missing OpenPGP keys from the key server, and add them
5962 to the user's GnuPG keyring.
5965 Never try to download missing OpenPGP keys. Instead just bail out.
5968 When a package signed with an unknown OpenPGP key is encountered, ask
5969 the user whether to download it or not. This is the default behavior.
5972 @item --key-server=@var{host}
5973 Use @var{host} as the OpenPGP key server when importing a public key.
5977 The @code{github} updater uses the
5978 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5979 releases. When used repeatedly e.g. when refreshing all packages,
5980 GitHub will eventually refuse to answer any further API requests. By
5981 default 60 API requests per hour are allowed, and a full refresh on all
5982 GitHub packages in Guix requires more than this. Authentication with
5983 GitHub through the use of an API token alleviates these limits. To use
5984 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5985 token procured from @uref{https://github.com/settings/tokens} or
5989 @node Invoking guix lint
5990 @section Invoking @command{guix lint}
5992 @cindex @command{guix lint}
5993 @cindex package, checking for errors
5994 The @command{guix lint} command is meant to help package developers avoid
5995 common errors and use a consistent style. It runs a number of checks on
5996 a given set of packages in order to find common mistakes in their
5997 definitions. Available @dfn{checkers} include (see
5998 @code{--list-checkers} for a complete list):
6003 Validate certain typographical and stylistic rules about package
6004 descriptions and synopses.
6006 @item inputs-should-be-native
6007 Identify inputs that should most likely be native inputs.
6012 @itemx source-file-name
6013 Probe @code{home-page} and @code{source} URLs and report those that are
6014 invalid. Suggest a @code{mirror://} URL when applicable. Check that
6015 the source file name is meaningful, e.g. is not
6016 just a version number or ``git-checkout'', without a declared
6017 @code{file-name} (@pxref{origin Reference}).
6020 @cindex security vulnerabilities
6021 @cindex CVE, Common Vulnerabilities and Exposures
6022 Report known vulnerabilities found in the Common Vulnerabilities and
6023 Exposures (CVE) databases of the current and past year
6024 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
6027 To view information about a particular vulnerability, visit pages such as:
6031 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
6033 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
6037 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
6038 @code{CVE-2015-7554}.
6040 Package developers can specify in package recipes the
6041 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
6042 name and version of the package when they differ from the name that Guix
6043 uses, as in this example:
6049 ;; CPE calls this package "grub2".
6050 (properties '((cpe-name . "grub2"))))
6054 Warn about obvious source code formatting issues: trailing white space,
6055 use of tabulations, etc.
6058 The general syntax is:
6061 guix lint @var{options} @var{package}@dots{}
6064 If no package is given on the command line, then all packages are checked.
6065 The @var{options} may be zero or more of the following:
6068 @item --list-checkers
6070 List and describe all the available checkers that will be run on packages
6075 Only enable the checkers specified in a comma-separated list using the
6076 names returned by @code{--list-checkers}.
6080 @node Invoking guix size
6081 @section Invoking @command{guix size}
6084 @cindex package size
6086 @cindex @command{guix size}
6087 The @command{guix size} command helps package developers profile the
6088 disk usage of packages. It is easy to overlook the impact of an
6089 additional dependency added to a package, or the impact of using a
6090 single output for a package that could easily be split (@pxref{Packages
6091 with Multiple Outputs}). Such are the typical issues that
6092 @command{guix size} can highlight.
6094 The command can be passed a package specification such as @code{gcc@@4.8}
6095 or @code{guile:debug}, or a file name in the store. Consider this
6099 $ guix size coreutils
6100 store item total self
6101 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6102 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6103 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6104 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6105 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6106 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6110 The store items listed here constitute the @dfn{transitive closure} of
6111 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6112 would be returned by:
6115 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6118 Here the output shows three columns next to store items. The first column,
6119 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6120 the store item---that is, its own size plus the size of all its
6121 dependencies. The next column, labeled ``self'', shows the size of the
6122 item itself. The last column shows the ratio of the size of the item
6123 itself to the space occupied by all the items listed here.
6125 In this example, we see that the closure of Coreutils weighs in at
6126 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6127 large fraction of the closure is not a problem @i{per se} because it is
6128 always available on the system anyway.)
6130 When the package passed to @command{guix size} is available in the
6131 store, @command{guix size} queries the daemon to determine its
6132 dependencies, and measures its size in the store, similar to @command{du
6133 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6136 When the given package is @emph{not} in the store, @command{guix size}
6137 reports information based on the available substitutes
6138 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6139 store items that are not even on disk, only available remotely.
6141 You can also specify several package names:
6144 $ guix size coreutils grep sed bash
6145 store item total self
6146 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6147 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6148 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6149 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6155 In this example we see that the combination of the four packages takes
6156 102.3@tie{}MiB in total, which is much less than the sum of each closure
6157 since they have a lot of dependencies in common.
6159 The available options are:
6163 @item --substitute-urls=@var{urls}
6164 Use substitute information from @var{urls}.
6165 @xref{client-substitute-urls, the same option for @code{guix build}}.
6167 @item --map-file=@var{file}
6168 Write a graphical map of disk usage in PNG format to @var{file}.
6170 For the example above, the map looks like this:
6172 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6173 produced by @command{guix size}}
6175 This option requires that
6176 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6177 installed and visible in Guile's module search path. When that is not
6178 the case, @command{guix size} fails as it tries to load it.
6180 @item --system=@var{system}
6181 @itemx -s @var{system}
6182 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6186 @node Invoking guix graph
6187 @section Invoking @command{guix graph}
6190 @cindex @command{guix graph}
6191 @cindex package dependencies
6192 Packages and their dependencies form a @dfn{graph}, specifically a
6193 directed acyclic graph (DAG). It can quickly become difficult to have a
6194 mental model of the package DAG, so the @command{guix graph} command
6195 provides a visual representation of the DAG. By default,
6196 @command{guix graph} emits a DAG representation in the input format of
6197 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6198 directly to the @command{dot} command of Graphviz. It can also emit an
6199 HTML page with embedded JavaScript code to display a ``chord diagram''
6200 in a Web browser, using the @uref{https://d3js.org/, d3.js} library, or
6201 emit Cypher queries to construct a graph in a graph database supporting
6202 the @uref{http://www.opencypher.org/, openCypher} query language.
6203 The general syntax is:
6206 guix graph @var{options} @var{package}@dots{}
6209 For example, the following command generates a PDF file representing the
6210 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6214 guix graph coreutils | dot -Tpdf > dag.pdf
6217 The output looks like this:
6219 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6221 Nice little graph, no?
6223 But there is more than one graph! The one above is concise: it is the
6224 graph of package objects, omitting implicit inputs such as GCC, libc,
6225 grep, etc. It is often useful to have such a concise graph, but
6226 sometimes one may want to see more details. @command{guix graph} supports
6227 several types of graphs, allowing you to choose the level of detail:
6231 This is the default type used in the example above. It shows the DAG of
6232 package objects, excluding implicit dependencies. It is concise, but
6233 filters out many details.
6235 @item reverse-package
6236 This shows the @emph{reverse} DAG of packages. For example:
6239 guix graph --type=reverse-package ocaml
6242 ... yields the graph of packages that depend on OCaml.
6244 Note that for core packages this can yield huge graphs. If all you want
6245 is to know the number of packages that depend on a given package, use
6246 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6247 @option{--list-dependent}}).
6250 This is the package DAG, @emph{including} implicit inputs.
6252 For instance, the following command:
6255 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6258 ... yields this bigger graph:
6260 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6262 At the bottom of the graph, we see all the implicit inputs of
6263 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6265 Now, note that the dependencies of these implicit inputs---that is, the
6266 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6267 here, for conciseness.
6270 Similar to @code{bag-emerged}, but this time including all the bootstrap
6273 @item bag-with-origins
6274 Similar to @code{bag}, but also showing origins and their dependencies.
6277 This is the most detailed representation: It shows the DAG of
6278 derivations (@pxref{Derivations}) and plain store items. Compared to
6279 the above representation, many additional nodes are visible, including
6280 build scripts, patches, Guile modules, etc.
6282 For this type of graph, it is also possible to pass a @file{.drv} file
6283 name instead of a package name, as in:
6286 guix graph -t derivation `guix system build -d my-config.scm`
6290 All the types above correspond to @emph{build-time dependencies}. The
6291 following graph type represents the @emph{run-time dependencies}:
6295 This is the graph of @dfn{references} of a package output, as returned
6296 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6298 If the given package output is not available in the store, @command{guix
6299 graph} attempts to obtain dependency information from substitutes.
6301 Here you can also pass a store file name instead of a package name. For
6302 example, the command below produces the reference graph of your profile
6303 (which can be big!):
6306 guix graph -t references `readlink -f ~/.guix-profile`
6310 This is the graph of the @dfn{referrers} of a store item, as returned by
6311 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6313 This relies exclusively on local information from your store. For
6314 instance, let us suppose that the current Inkscape is available in 10
6315 profiles on your machine; @command{guix graph -t referrers inkscape}
6316 will show a graph rooted at Inkscape and with those 10 profiles linked
6319 It can help determine what is preventing a store item from being garbage
6324 The available options are the following:
6327 @item --type=@var{type}
6328 @itemx -t @var{type}
6329 Produce a graph output of @var{type}, where @var{type} must be one of
6330 the values listed above.
6333 List the supported graph types.
6335 @item --backend=@var{backend}
6336 @itemx -b @var{backend}
6337 Produce a graph using the selected @var{backend}.
6339 @item --list-backends
6340 List the supported graph backends.
6342 Currently, the available backends are Graphviz and d3.js.
6344 @item --expression=@var{expr}
6345 @itemx -e @var{expr}
6346 Consider the package @var{expr} evaluates to.
6348 This is useful to precisely refer to a package, as in this example:
6351 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6356 @node Invoking guix environment
6357 @section Invoking @command{guix environment}
6359 @cindex reproducible build environments
6360 @cindex development environments
6361 @cindex @command{guix environment}
6362 @cindex environment, package build environment
6363 The purpose of @command{guix environment} is to assist hackers in
6364 creating reproducible development environments without polluting their
6365 package profile. The @command{guix environment} tool takes one or more
6366 packages, builds all of their inputs, and creates a shell
6367 environment to use them.
6369 The general syntax is:
6372 guix environment @var{options} @var{package}@dots{}
6375 The following example spawns a new shell set up for the development of
6379 guix environment guile
6382 If the needed dependencies are not built yet, @command{guix environment}
6383 automatically builds them. The environment of the new shell is an augmented
6384 version of the environment that @command{guix environment} was run in.
6385 It contains the necessary search paths for building the given package
6386 added to the existing environment variables. To create a ``pure''
6387 environment, in which the original environment variables have been unset,
6388 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6389 environment variables such as @code{PATH} in their @file{~/.bashrc}
6390 file. As a consequence, when @code{guix environment} launches it, Bash
6391 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6392 environment variables. It is an error to define such environment
6393 variables in @file{.bashrc}; instead, they should be defined in
6394 @file{.bash_profile}, which is sourced only by log-in shells.
6395 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6396 details on Bash start-up files.}.
6398 @vindex GUIX_ENVIRONMENT
6399 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6400 variable in the shell it spawns; its value is the file name of the
6401 profile of this environment. This allows users to, say, define a
6402 specific prompt for development environments in their @file{.bashrc}
6403 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6406 if [ -n "$GUIX_ENVIRONMENT" ]
6408 export PS1="\u@@\h \w [dev]\$ "
6413 ... or to browse the profile:
6416 $ ls "$GUIX_ENVIRONMENT/bin"
6419 Additionally, more than one package may be specified, in which case the
6420 union of the inputs for the given packages are used. For example, the
6421 command below spawns a shell where all of the dependencies of both Guile
6422 and Emacs are available:
6425 guix environment guile emacs
6428 Sometimes an interactive shell session is not desired. An arbitrary
6429 command may be invoked by placing the @code{--} token to separate the
6430 command from the rest of the arguments:
6433 guix environment guile -- make -j4
6436 In other situations, it is more convenient to specify the list of
6437 packages needed in the environment. For example, the following command
6438 runs @command{python} from an environment containing Python@tie{}2.7 and
6442 guix environment --ad-hoc python2-numpy python-2.7 -- python
6445 Furthermore, one might want the dependencies of a package and also some
6446 additional packages that are not build-time or runtime dependencies, but
6447 are useful when developing nonetheless. Because of this, the
6448 @code{--ad-hoc} flag is positional. Packages appearing before
6449 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6450 added to the environment. Packages appearing after are interpreted as
6451 packages that will be added to the environment directly. For example,
6452 the following command creates a Guix development environment that
6453 additionally includes Git and strace:
6456 guix environment guix --ad-hoc git strace
6459 Sometimes it is desirable to isolate the environment as much as
6460 possible, for maximal purity and reproducibility. In particular, when
6461 using Guix on a host distro that is not GuixSD, it is desirable to
6462 prevent access to @file{/usr/bin} and other system-wide resources from
6463 the development environment. For example, the following command spawns
6464 a Guile REPL in a ``container'' where only the store and the current
6465 working directory are mounted:
6468 guix environment --ad-hoc --container guile -- guile
6472 The @code{--container} option requires Linux-libre 3.19 or newer.
6475 The available options are summarized below.
6478 @item --root=@var{file}
6479 @itemx -r @var{file}
6480 @cindex persistent environment
6481 @cindex garbage collector root, for environments
6482 Make @var{file} a symlink to the profile for this environment, and
6483 register it as a garbage collector root.
6485 This is useful if you want to protect your environment from garbage
6486 collection, to make it ``persistent''.
6488 When this option is omitted, the environment is protected from garbage
6489 collection only for the duration of the @command{guix environment}
6490 session. This means that next time you recreate the same environment,
6491 you could have to rebuild or re-download packages.
6493 @item --expression=@var{expr}
6494 @itemx -e @var{expr}
6495 Create an environment for the package or list of packages that
6496 @var{expr} evaluates to.
6498 For example, running:
6501 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6504 starts a shell with the environment for this specific variant of the
6510 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6513 starts a shell with all the GuixSD base packages available.
6515 The above commands only use the default output of the given packages.
6516 To select other outputs, two element tuples can be specified:
6519 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6522 @item --load=@var{file}
6523 @itemx -l @var{file}
6524 Create an environment for the package or list of packages that the code
6525 within @var{file} evaluates to.
6527 As an example, @var{file} might contain a definition like this
6528 (@pxref{Defining Packages}):
6531 @verbatiminclude environment-gdb.scm
6535 Include all specified packages in the resulting environment, as if an
6536 @i{ad hoc} package were defined with them as inputs. This option is
6537 useful for quickly creating an environment without having to write a
6538 package expression to contain the desired inputs.
6540 For instance, the command:
6543 guix environment --ad-hoc guile guile-sdl -- guile
6546 runs @command{guile} in an environment where Guile and Guile-SDL are
6549 Note that this example implicitly asks for the default output of
6550 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6551 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6552 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6554 This option may be composed with the default behavior of @command{guix
6555 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6556 as packages whose dependencies will be added to the environment, the
6557 default behavior. Packages appearing after are interpreted as packages
6558 that will be added to the environment directly.
6561 Unset existing environment variables when building the new environment.
6562 This has the effect of creating an environment in which search paths
6563 only contain package inputs.
6565 @item --search-paths
6566 Display the environment variable definitions that make up the
6569 @item --system=@var{system}
6570 @itemx -s @var{system}
6571 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6576 Run @var{command} within an isolated container. The current working
6577 directory outside the container is mapped inside the container.
6578 Additionally, a dummy home directory is created that matches the current
6579 user's home directory, and @file{/etc/passwd} is configured accordingly.
6580 The spawned process runs as the current user outside the container, but
6581 has root privileges in the context of the container.
6585 For containers, share the network namespace with the host system.
6586 Containers created without this flag only have access to the loopback
6589 @item --expose=@var{source}[=@var{target}]
6590 For containers, expose the file system @var{source} from the host system
6591 as the read-only file system @var{target} within the container. If
6592 @var{target} is not specified, @var{source} is used as the target mount
6593 point in the container.
6595 The example below spawns a Guile REPL in a container in which the user's
6596 home directory is accessible read-only via the @file{/exchange}
6600 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6603 @item --share=@var{source}[=@var{target}]
6604 For containers, share the file system @var{source} from the host system
6605 as the writable file system @var{target} within the container. If
6606 @var{target} is not specified, @var{source} is used as the target mount
6607 point in the container.
6609 The example below spawns a Guile REPL in a container in which the user's
6610 home directory is accessible for both reading and writing via the
6611 @file{/exchange} directory:
6614 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6618 @command{guix environment}
6619 also supports all of the common build options that @command{guix
6620 build} supports (@pxref{Common Build Options}).
6623 @node Invoking guix publish
6624 @section Invoking @command{guix publish}
6626 @cindex @command{guix publish}
6627 The purpose of @command{guix publish} is to enable users to easily share
6628 their store with others, who can then use it as a substitute server
6629 (@pxref{Substitutes}).
6631 When @command{guix publish} runs, it spawns an HTTP server which allows
6632 anyone with network access to obtain substitutes from it. This means
6633 that any machine running Guix can also act as if it were a build farm,
6634 since the HTTP interface is compatible with Hydra, the software behind
6635 the @code{hydra.gnu.org} build farm.
6637 For security, each substitute is signed, allowing recipients to check
6638 their authenticity and integrity (@pxref{Substitutes}). Because
6639 @command{guix publish} uses the signing key of the system, which is only
6640 readable by the system administrator, it must be started as root; the
6641 @code{--user} option makes it drop root privileges early on.
6643 The signing key pair must be generated before @command{guix publish} is
6644 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6647 The general syntax is:
6650 guix publish @var{options}@dots{}
6653 Running @command{guix publish} without any additional arguments will
6654 spawn an HTTP server on port 8080:
6660 Once a publishing server has been authorized (@pxref{Invoking guix
6661 archive}), the daemon may download substitutes from it:
6664 guix-daemon --substitute-urls=http://example.org:8080
6667 By default, @command{guix publish} compresses archives on the fly as it
6668 serves them. This ``on-the-fly'' mode is convenient in that it requires
6669 no setup and is immediately available. However, when serving lots of
6670 clients, we recommend using the @option{--cache} option, which enables
6671 caching of the archives before they are sent to clients---see below for
6674 As a bonus, @command{guix publish} also serves as a content-addressed
6675 mirror for source files referenced in @code{origin} records
6676 (@pxref{origin Reference}). For instance, assuming @command{guix
6677 publish} is running on @code{example.org}, the following URL returns the
6678 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6679 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6682 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6685 Obviously, these URLs only work for files that are in the store; in
6686 other cases, they return 404 (``Not Found'').
6688 The following options are available:
6691 @item --port=@var{port}
6692 @itemx -p @var{port}
6693 Listen for HTTP requests on @var{port}.
6695 @item --listen=@var{host}
6696 Listen on the network interface for @var{host}. The default is to
6697 accept connections from any interface.
6699 @item --user=@var{user}
6700 @itemx -u @var{user}
6701 Change privileges to @var{user} as soon as possible---i.e., once the
6702 server socket is open and the signing key has been read.
6704 @item --compression[=@var{level}]
6705 @itemx -C [@var{level}]
6706 Compress data using the given @var{level}. When @var{level} is zero,
6707 disable compression. The range 1 to 9 corresponds to different gzip
6708 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6711 Unless @option{--cache} is used, compression occurs on the fly and
6712 the compressed streams are not
6713 cached. Thus, to reduce load on the machine that runs @command{guix
6714 publish}, it may be a good idea to choose a low compression level, to
6715 run @command{guix publish} behind a caching proxy, or to use
6716 @option{--cache}. Using @option{--cache} has the advantage that it
6717 allows @command{guix publish} to add @code{Content-Length} HTTP header
6720 @item --cache=@var{directory}
6721 @itemx -c @var{directory}
6722 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6723 and only serve archives that are in cache.
6725 When this option is omitted, archives and meta-data are created
6726 on-the-fly. This can reduce the available bandwidth, especially when
6727 compression is enabled, since this may become CPU-bound. Another
6728 drawback of the default mode is that the length of archives is not known
6729 in advance, so @command{guix publish} does not add a
6730 @code{Content-Length} HTTP header to its responses, which in turn
6731 prevents clients from knowing the amount of data being downloaded.
6733 Conversely, when @option{--cache} is used, the first request for a store
6734 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6735 background process to @dfn{bake} the archive---computing its
6736 @code{.narinfo} and compressing the archive, if needed. Once the
6737 archive is cached in @var{directory}, subsequent requests succeed and
6738 are served directly from the cache, which guarantees that clients get
6739 the best possible bandwidth.
6741 The ``baking'' process is performed by worker threads. By default, one
6742 thread per CPU core is created, but this can be customized. See
6743 @option{--workers} below.
6745 When @option{--ttl} is used, cached entries are automatically deleted
6746 when they have expired.
6748 @item --workers=@var{N}
6749 When @option{--cache} is used, request the allocation of @var{N} worker
6750 threads to ``bake'' archives.
6752 @item --ttl=@var{ttl}
6753 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6754 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6755 days, @code{1m} means 1 month, and so on.
6757 This allows the user's Guix to keep substitute information in cache for
6758 @var{ttl}. However, note that @code{guix publish} does not itself
6759 guarantee that the store items it provides will indeed remain available
6760 for as long as @var{ttl}.
6762 Additionally, when @option{--cache} is used, cached entries that have
6763 not been accessed for @var{ttl} may be deleted.
6765 @item --nar-path=@var{path}
6766 Use @var{path} as the prefix for the URLs of ``nar'' files
6767 (@pxref{Invoking guix archive, normalized archives}).
6769 By default, nars are served at a URL such as
6770 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6771 change the @code{/nar} part to @var{path}.
6773 @item --public-key=@var{file}
6774 @itemx --private-key=@var{file}
6775 Use the specific @var{file}s as the public/private key pair used to sign
6776 the store items being published.
6778 The files must correspond to the same key pair (the private key is used
6779 for signing and the public key is merely advertised in the signature
6780 metadata). They must contain keys in the canonical s-expression format
6781 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6782 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6783 @file{/etc/guix/signing-key.sec} are used.
6785 @item --repl[=@var{port}]
6786 @itemx -r [@var{port}]
6787 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6788 Reference Manual}) on @var{port} (37146 by default). This is used
6789 primarily for debugging a running @command{guix publish} server.
6792 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6793 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6794 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6795 @code{guix-publish-service-type}}).
6797 If you are instead running Guix on a ``foreign distro'', follow these
6802 If your host distro uses the systemd init system:
6805 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6806 /etc/systemd/system/
6807 # systemctl start guix-publish && systemctl enable guix-publish
6811 If your host distro uses the Upstart init system:
6814 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6815 # start guix-publish
6819 Otherwise, proceed similarly with your distro's init system.
6822 @node Invoking guix challenge
6823 @section Invoking @command{guix challenge}
6825 @cindex reproducible builds
6826 @cindex verifiable builds
6827 @cindex @command{guix challenge}
6829 Do the binaries provided by this server really correspond to the source
6830 code it claims to build? Is a package build process deterministic?
6831 These are the questions the @command{guix challenge} command attempts to
6834 The former is obviously an important question: Before using a substitute
6835 server (@pxref{Substitutes}), one had better @emph{verify} that it
6836 provides the right binaries, and thus @emph{challenge} it. The latter
6837 is what enables the former: If package builds are deterministic, then
6838 independent builds of the package should yield the exact same result,
6839 bit for bit; if a server provides a binary different from the one
6840 obtained locally, it may be either corrupt or malicious.
6842 We know that the hash that shows up in @file{/gnu/store} file names is
6843 the hash of all the inputs of the process that built the file or
6844 directory---compilers, libraries, build scripts,
6845 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6846 one store file name should map to exactly one build output.
6847 @command{guix challenge} checks whether there is, indeed, a single
6848 mapping by comparing the build outputs of several independent builds of
6849 any given store item.
6851 The command output looks like this:
6854 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6855 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6856 updating list of substitutes from 'https://guix.example.org'... 100.0%
6857 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6858 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6859 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6860 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6861 /gnu/store/@dots{}-git-2.5.0 contents differ:
6862 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6863 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6864 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6865 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6866 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6867 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6868 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6872 In this example, @command{guix challenge} first scans the store to
6873 determine the set of locally-built derivations---as opposed to store
6874 items that were downloaded from a substitute server---and then queries
6875 all the substitute servers. It then reports those store items for which
6876 the servers obtained a result different from the local build.
6878 @cindex non-determinism, in package builds
6879 As an example, @code{guix.example.org} always gets a different answer.
6880 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6881 case of Git. This might indicate that the build process of Git is
6882 non-deterministic, meaning that its output varies as a function of
6883 various things that Guix does not fully control, in spite of building
6884 packages in isolated environments (@pxref{Features}). Most common
6885 sources of non-determinism include the addition of timestamps in build
6886 results, the inclusion of random numbers, and directory listings sorted
6887 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6890 To find out what is wrong with this Git binary, we can do something along
6891 these lines (@pxref{Invoking guix archive}):
6894 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6895 | guix archive -x /tmp/git
6896 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6899 This command shows the difference between the files resulting from the
6900 local build, and the files resulting from the build on
6901 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6902 diffutils, Comparing and Merging Files}). The @command{diff} command
6903 works great for text files. When binary files differ, a better option
6904 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6905 visualize differences for all kinds of files.
6907 Once you have done that work, you can tell whether the differences are due
6908 to a non-deterministic build process or to a malicious server. We try
6909 hard to remove sources of non-determinism in packages to make it easier
6910 to verify substitutes, but of course, this is a process that
6911 involves not just Guix, but a large part of the free software community.
6912 In the meantime, @command{guix challenge} is one tool to help address
6915 If you are writing packages for Guix, you are encouraged to check
6916 whether @code{hydra.gnu.org} and other substitute servers obtain the
6917 same build result as you did with:
6920 $ guix challenge @var{package}
6924 where @var{package} is a package specification such as
6925 @code{guile@@2.0} or @code{glibc:debug}.
6927 The general syntax is:
6930 guix challenge @var{options} [@var{packages}@dots{}]
6933 When a difference is found between the hash of a locally-built item and
6934 that of a server-provided substitute, or among substitutes provided by
6935 different servers, the command displays it as in the example above and
6936 its exit code is 2 (other non-zero exit codes denote other kinds of
6939 The one option that matters is:
6943 @item --substitute-urls=@var{urls}
6944 Consider @var{urls} the whitespace-separated list of substitute source
6949 Show details about matches (identical contents) in addition to
6950 information about mismatches.
6954 @node Invoking guix copy
6955 @section Invoking @command{guix copy}
6957 @cindex copy, of store items, over SSH
6958 @cindex SSH, copy of store items
6959 @cindex sharing store items across machines
6960 @cindex transferring store items across machines
6961 The @command{guix copy} command copies items from the store of one
6962 machine to that of another machine over a secure shell (SSH)
6963 connection@footnote{This command is available only when Guile-SSH was
6964 found. @xref{Requirements}, for details.}. For example, the following
6965 command copies the @code{coreutils} package, the user's profile, and all
6966 their dependencies over to @var{host}, logged in as @var{user}:
6969 guix copy --to=@var{user}@@@var{host} \
6970 coreutils `readlink -f ~/.guix-profile`
6973 If some of the items to be copied are already present on @var{host},
6974 they are not actually sent.
6976 The command below retrieves @code{libreoffice} and @code{gimp} from
6977 @var{host}, assuming they are available there:
6980 guix copy --from=@var{host} libreoffice gimp
6983 The SSH connection is established using the Guile-SSH client, which is
6984 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6985 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6987 The key used to sign items that are sent must be accepted by the remote
6988 machine. Likewise, the key used by the remote machine to sign items you
6989 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6990 own daemon. @xref{Invoking guix archive}, for more information about
6991 store item authentication.
6993 The general syntax is:
6996 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6999 You must always specify one of the following options:
7002 @item --to=@var{spec}
7003 @itemx --from=@var{spec}
7004 Specify the host to send to or receive from. @var{spec} must be an SSH
7005 spec such as @code{example.org}, @code{charlie@@example.org}, or
7006 @code{charlie@@example.org:2222}.
7009 The @var{items} can be either package names, such as @code{gimp}, or
7010 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
7012 When specifying the name of a package to send, it is first built if
7013 needed, unless @option{--dry-run} was specified. Common build options
7014 are supported (@pxref{Common Build Options}).
7017 @node Invoking guix container
7018 @section Invoking @command{guix container}
7020 @cindex @command{guix container}
7022 As of version @value{VERSION}, this tool is experimental. The interface
7023 is subject to radical change in the future.
7026 The purpose of @command{guix container} is to manipulate processes
7027 running within an isolated environment, commonly known as a
7028 ``container'', typically created by the @command{guix environment}
7029 (@pxref{Invoking guix environment}) and @command{guix system container}
7030 (@pxref{Invoking guix system}) commands.
7032 The general syntax is:
7035 guix container @var{action} @var{options}@dots{}
7038 @var{action} specifies the operation to perform with a container, and
7039 @var{options} specifies the context-specific arguments for the action.
7041 The following actions are available:
7045 Execute a command within the context of a running container.
7050 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
7053 @var{pid} specifies the process ID of the running container.
7054 @var{program} specifies an executable file name within the root file
7055 system of the container. @var{arguments} are the additional options that
7056 will be passed to @var{program}.
7058 The following command launches an interactive login shell inside a
7059 GuixSD container, started by @command{guix system container}, and whose
7063 guix container exec 9001 /run/current-system/profile/bin/bash --login
7066 Note that the @var{pid} cannot be the parent process of a container. It
7067 must be PID 1 of the container or one of its child processes.
7071 @c *********************************************************************
7072 @node GNU Distribution
7073 @chapter GNU Distribution
7075 @cindex Guix System Distribution
7077 Guix comes with a distribution of the GNU system consisting entirely of
7078 free software@footnote{The term ``free'' here refers to the
7079 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
7080 users of that software}.}. The
7081 distribution can be installed on its own (@pxref{System Installation}),
7082 but it is also possible to install Guix as a package manager on top of
7083 an installed GNU/Linux system (@pxref{Installation}). To distinguish
7084 between the two, we refer to the standalone distribution as the Guix
7085 System Distribution, or GuixSD.
7087 The distribution provides core GNU packages such as GNU libc, GCC, and
7088 Binutils, as well as many GNU and non-GNU applications. The complete
7089 list of available packages can be browsed
7090 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7091 running @command{guix package} (@pxref{Invoking guix package}):
7094 guix package --list-available
7097 Our goal is to provide a practical 100% free software distribution of
7098 Linux-based and other variants of GNU, with a focus on the promotion and
7099 tight integration of GNU components, and an emphasis on programs and
7100 tools that help users exert that freedom.
7102 Packages are currently available on the following platforms:
7107 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7110 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7113 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7114 using the EABI hard-float application binary interface (ABI),
7115 and Linux-Libre kernel.
7118 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7119 currently in an experimental stage, with limited support.
7120 @xref{Contributing}, for how to help!
7122 @item mips64el-linux
7123 little-endian 64-bit MIPS processors, specifically the Loongson series,
7124 n32 ABI, and Linux-Libre kernel.
7128 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7131 For information on porting to other architectures or kernels,
7135 * System Installation:: Installing the whole operating system.
7136 * System Configuration:: Configuring the operating system.
7137 * Documentation:: Browsing software user manuals.
7138 * Installing Debugging Files:: Feeding the debugger.
7139 * Security Updates:: Deploying security fixes quickly.
7140 * Package Modules:: Packages from the programmer's viewpoint.
7141 * Packaging Guidelines:: Growing the distribution.
7142 * Bootstrapping:: GNU/Linux built from scratch.
7143 * Porting:: Targeting another platform or kernel.
7146 Building this distribution is a cooperative effort, and you are invited
7147 to join! @xref{Contributing}, for information about how you can help.
7149 @node System Installation
7150 @section System Installation
7152 @cindex installing GuixSD
7153 @cindex Guix System Distribution
7154 This section explains how to install the Guix System Distribution (GuixSD)
7155 on a machine. The Guix package manager can
7156 also be installed on top of a running GNU/Linux system,
7157 @pxref{Installation}.
7161 @c This paragraph is for people reading this from tty2 of the
7162 @c installation image.
7163 You are reading this documentation with an Info reader. For details on
7164 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7165 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7166 Info}. Hit @kbd{l} afterwards to come back here.
7168 Alternately, run @command{info info} in another tty to keep the manual
7174 * Limitations:: What you can expect.
7175 * Hardware Considerations:: Supported hardware.
7176 * USB Stick Installation:: Preparing the installation medium.
7177 * Preparing for Installation:: Networking, partitioning, etc.
7178 * Proceeding with the Installation:: The real thing.
7179 * Installing GuixSD in a VM:: GuixSD playground.
7180 * Building the Installation Image:: How this comes to be.
7184 @subsection Limitations
7186 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7187 not production-ready. It may contain bugs and lack important
7188 features. Thus, if you are looking for a stable production system that
7189 respects your freedom as a computer user, a good solution at this point
7190 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7191 the more established GNU/Linux distributions}. We hope you can soon switch
7192 to the GuixSD without fear, of course. In the meantime, you can
7193 also keep using your distribution and try out the package manager on top
7194 of it (@pxref{Installation}).
7196 Before you proceed with the installation, be aware of the following
7197 noteworthy limitations applicable to version @value{VERSION}:
7201 The installation process does not include a graphical user interface and
7202 requires familiarity with GNU/Linux (see the following subsections to
7203 get a feel of what that means.)
7206 Support for the Logical Volume Manager (LVM) is missing.
7209 More and more system services are provided (@pxref{Services}), but some
7213 More than 5,300 packages are available, but you may
7214 occasionally find that a useful package is missing.
7217 GNOME, Xfce, LXDE, and Enlightenment are available (@pxref{Desktop Services}),
7218 as well as a number of X11 window managers. However, some graphical
7219 applications may be missing, as well as KDE.
7222 You have been warned! But more than a disclaimer, this is an invitation
7223 to report issues (and success stories!), and to join us in improving it.
7224 @xref{Contributing}, for more info.
7227 @node Hardware Considerations
7228 @subsection Hardware Considerations
7230 @cindex hardware support on GuixSD
7231 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7232 builds around the kernel Linux-libre, which means that only hardware for
7233 which free software drivers and firmware exist is supported. Nowadays,
7234 a wide range of off-the-shelf hardware is supported on
7235 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7236 Ethernet controllers. Unfortunately, there are still areas where
7237 hardware vendors deny users control over their own computing, and such
7238 hardware is not supported on GuixSD.
7240 @cindex WiFi, hardware support
7241 One of the main areas where free drivers or firmware are lacking is WiFi
7242 devices. WiFi devices known to work include those using Atheros chips
7243 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7244 driver, and those using Broadcom/AirForce chips (BCM43xx with
7245 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7246 Linux-libre driver. Free firmware exists for both and is available
7247 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7248 (@pxref{operating-system Reference, @code{firmware}}).
7250 @cindex RYF, Respects Your Freedom
7251 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7252 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7253 certification program for hardware products that respect your freedom
7254 and your privacy and ensure that you have control over your device. We
7255 encourage you to check the list of RYF-certified devices.
7257 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7258 web site. It contains a catalog of hardware devices with information
7259 about their support in GNU/Linux.
7262 @node USB Stick Installation
7263 @subsection USB Stick Installation
7265 An installation image for USB sticks can be downloaded from
7266 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7267 where @var{system} is one of:
7271 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7274 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7277 @c start duplication of authentication part from ``Binary Installation''
7278 Make sure to download the associated @file{.sig} file and to verify the
7279 authenticity of the image against it, along these lines:
7282 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7283 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7286 If that command fails because you do not have the required public key,
7287 then run this command to import it:
7290 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7294 and rerun the @code{gpg --verify} command.
7297 This image contains a single partition with the tools necessary for an
7298 installation. It is meant to be copied @emph{as is} to a large-enough
7301 To copy the image to a USB stick, follow these steps:
7305 Decompress the image using the @command{xz} command:
7308 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7312 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7313 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7314 copy the image with:
7317 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7321 Access to @file{/dev/sdX} usually requires root privileges.
7324 Once this is done, you should be able to reboot the system and boot from
7325 the USB stick. The latter usually requires you to get in the BIOS' or
7326 UEFI boot menu, where you can choose to boot from the USB stick.
7328 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7329 GuixSD in a virtual machine (VM).
7331 @node Preparing for Installation
7332 @subsection Preparing for Installation
7334 Once you have successfully booted the image on the USB stick, you should
7335 end up with a root prompt. Several console TTYs are configured and can
7336 be used to run commands as root. TTY2 shows this documentation,
7337 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7338 Stand-alone GNU Info}). The installation system runs the GPM mouse
7339 daemon, which allows you to select text with the left mouse button and
7340 to paste it with the middle button.
7343 Installation requires access to the Internet so that any missing
7344 dependencies of your system configuration can be downloaded. See the
7345 ``Networking'' section below.
7348 The installation system includes many common tools needed for this task.
7349 But it is also a full-blown GuixSD system, which means that you can
7350 install additional packages, should you need it, using @command{guix
7351 package} (@pxref{Invoking guix package}).
7353 @subsubsection Keyboard Layout
7355 @cindex keyboard layout
7356 The installation image uses the US qwerty keyboard layout. If you want
7357 to change it, you can use the @command{loadkeys} command. For example,
7358 the following command selects the Dvorak keyboard layout:
7364 See the files under @file{/run/current-system/profile/share/keymaps} for
7365 a list of available keyboard layouts. Run @command{man loadkeys} for
7368 @subsubsection Networking
7370 Run the following command see what your network interfaces are called:
7377 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7383 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7384 Wired interfaces have a name starting with @samp{e}; for example, the
7385 interface corresponding to the first on-board Ethernet controller is
7386 called @samp{eno1}. Wireless interfaces have a name starting with
7387 @samp{w}, like @samp{w1p2s0}.
7390 @item Wired connection
7391 To configure a wired network run the following command, substituting
7392 @var{interface} with the name of the wired interface you want to use.
7395 ifconfig @var{interface} up
7398 @item Wireless connection
7401 To configure wireless networking, you can create a configuration file
7402 for the @command{wpa_supplicant} configuration tool (its location is not
7403 important) using one of the available text editors such as
7407 zile wpa_supplicant.conf
7410 As an example, the following stanza can go to this file and will work
7411 for many wireless networks, provided you give the actual SSID and
7412 passphrase for the network you are connecting to:
7416 ssid="@var{my-ssid}"
7418 psk="the network's secret passphrase"
7422 Start the wireless service and run it in the background with the
7423 following command (substitute @var{interface} with the name of the
7424 network interface you want to use):
7427 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7430 Run @command{man wpa_supplicant} for more information.
7434 At this point, you need to acquire an IP address. On a network where IP
7435 addresses are automatically assigned @i{via} DHCP, you can run:
7438 dhclient -v @var{interface}
7441 Try to ping a server to see if networking is up and running:
7447 Setting up network access is almost always a requirement because the
7448 image does not contain all the software and tools that may be needed.
7450 @cindex installing over SSH
7451 If you want to, you can continue the installation remotely by starting
7455 herd start ssh-daemon
7458 Make sure to either set a password with @command{passwd}, or configure
7459 OpenSSH public key authentication before logging in.
7461 @subsubsection Disk Partitioning
7463 Unless this has already been done, the next step is to partition, and
7464 then format the target partition(s).
7466 The installation image includes several partitioning tools, including
7467 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7468 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7469 the partition layout you want:
7475 If your disk uses the GUID Partition Table (GPT) format and you plan to
7476 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7477 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7480 @cindex EFI, installation
7481 @cindex UEFI, installation
7482 @cindex ESP, EFI system partition
7483 If you instead wish to use EFI-based GRUB, a FAT32 @dfn{EFI System Partition}
7484 (ESP) is required. This partition should be mounted at @file{/boot/efi} and
7485 must have the @code{esp} flag set. E.g., for @command{parted}:
7488 parted /dev/sda set 1 esp on
7491 Once you are done partitioning the target hard disk drive, you have to
7492 create a file system on the relevant partition(s)@footnote{Currently
7493 GuixSD only supports ext4 and btrfs file systems. In particular, code
7494 that reads partition UUIDs and labels only works for these file system
7497 Preferably, assign partitions a label so that you can easily and
7498 reliably refer to them in @code{file-system} declarations (@pxref{File
7499 Systems}). This is typically done using the @code{-L} option of
7500 @command{mkfs.ext4} and related commands. So, assuming the target root
7501 partition lives at @file{/dev/sda1}, a file system with the label
7502 @code{my-root} can be created with:
7505 mkfs.ext4 -L my-root /dev/sda1
7508 @cindex encrypted disk
7509 If you are instead planning to encrypt the root partition, you can use
7510 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7511 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7512 @code{man cryptsetup}} for more information.) Assuming you want to
7513 store the root partition on @file{/dev/sda1}, the command sequence would
7514 be along these lines:
7517 cryptsetup luksFormat /dev/sda1
7518 cryptsetup open --type luks /dev/sda1 my-partition
7519 mkfs.ext4 -L my-root /dev/mapper/my-partition
7522 Once that is done, mount the target root partition under @file{/mnt}
7523 with a command like (again, assuming @code{my-root} is the label of the
7527 mount LABEL=my-root /mnt
7530 Also mount any other partitions you would like to use on the target
7531 system relative to this path. If you have @file{/boot} on a separate
7532 partition for example, mount it at @file{/mnt/boot} now so it is found
7533 by @code{guix system init} afterwards.
7535 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7536 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7537 sure to initialize them with @command{mkswap}. Assuming you have one
7538 swap partition on @file{/dev/sda2}, you would run:
7545 Alternatively, you may use a swap file. For example, assuming that in
7546 the new system you want to use the file @file{/swapfile} as a swap file,
7547 you would run@footnote{This example will work for many types of file
7548 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7549 btrfs), the required steps may be different. For details, see the
7550 manual pages for @command{mkswap} and @command{swapon}.}:
7553 # This is 10 GiB of swap space. Adjust "count" to change the size.
7554 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7555 # For security, make the file readable and writable only by root.
7556 chmod 600 /mnt/swapfile
7557 mkswap /mnt/swapfile
7558 swapon /mnt/swapfile
7561 Note that if you have encrypted the root partition and created a swap
7562 file in its file system as described above, then the encryption also
7563 protects the swap file, just like any other file in that file system.
7565 @node Proceeding with the Installation
7566 @subsection Proceeding with the Installation
7568 With the target partitions ready and the target root mounted on
7569 @file{/mnt}, we're ready to go. First, run:
7572 herd start cow-store /mnt
7575 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7576 during the installation phase are written to the target disk on @file{/mnt}
7577 rather than kept in memory. This is necessary because the first phase of
7578 the @command{guix system init} command (see below) entails downloads or
7579 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7581 Next, you have to edit a file and
7582 provide the declaration of the operating system to be installed. To
7583 that end, the installation system comes with three text editors: GNU nano
7584 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7585 nvi (a clone of the original BSD @command{vi} editor).
7586 We strongly recommend storing that file on the target root file system, say,
7587 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7588 configuration file once you have rebooted into the newly-installed system.
7590 @xref{Using the Configuration System}, for an overview of the
7591 configuration file. The example configurations discussed in that
7592 section are available under @file{/etc/configuration} in the
7593 installation image. Thus, to get started with a system configuration
7594 providing a graphical display server (a ``desktop'' system), you can run
7595 something along these lines:
7599 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7600 # zile /mnt/etc/config.scm
7603 You should pay attention to what your configuration file contains, and
7608 Make sure the @code{grub-configuration} form refers to the device you
7609 want to install GRUB on. You also need to specify the @code{grub-efi}
7610 package if you wish to use native UEFI boot.
7613 Be sure that your partition labels match the value of their respective
7614 @code{device} fields in your @code{file-system} configuration, assuming
7615 your @code{file-system} configuration sets the value of @code{title} to
7619 If there are encrypted or RAID partitions, make sure to add a
7620 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7623 Once you are done preparing the configuration file, the new system must
7624 be initialized (remember that the target root file system is mounted
7628 guix system init /mnt/etc/config.scm /mnt
7632 This copies all the necessary files and installs GRUB on
7633 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7634 more information, @pxref{Invoking guix system}. This command may trigger
7635 downloads or builds of missing packages, which can take some time.
7637 Once that command has completed---and hopefully succeeded!---you can run
7638 @command{reboot} and boot into the new system. The @code{root} password
7639 in the new system is initially empty; other users' passwords need to be
7640 initialized by running the @command{passwd} command as @code{root},
7641 unless your configuration specifies otherwise
7642 (@pxref{user-account-password, user account passwords}).
7644 @cindex upgrading GuixSD
7645 From then on, you can update GuixSD whenever you want by running
7646 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7647 then running @command{guix system reconfigure} to build a new system
7648 generation with the latest packages and services (@pxref{Invoking guix
7649 system}). We recommend doing that regularly so that your system
7650 includes the latest security updates (@pxref{Security Updates}).
7652 Join us on @code{#guix} on the Freenode IRC network or on
7653 @file{guix-devel@@gnu.org} to share your experience---good or not so
7656 @node Installing GuixSD in a VM
7657 @subsection Installing GuixSD in a Virtual Machine
7659 @cindex virtual machine, GuixSD installation
7660 @cindex virtual private server (VPS)
7661 @cindex VPS (virtual private server)
7662 If you'd like to install GuixSD in a virtual machine (VM) or on a
7663 virtual private server (VPS) rather than on your beloved machine, this
7666 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7667 disk image, follow these steps:
7671 First, retrieve and decompress the GuixSD installation image as
7672 described previously (@pxref{USB Stick Installation}).
7675 Create a disk image that will hold the installed system. To make a
7676 qcow2-formatted disk image, use the @command{qemu-img} command:
7679 qemu-img create -f qcow2 guixsd.img 5G
7682 This will create a 5GB file.
7685 Boot the USB installation image in an VM:
7688 qemu-system-x86_64 -m 1024 -smp 1 \
7689 -net user -net nic,model=virtio -boot menu=on \
7690 -drive file=guixsd.img \
7691 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7694 In the VM console, quickly press the @kbd{F12} key to enter the boot
7695 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7699 You're now root in the VM, proceed with the installation process.
7700 @xref{Preparing for Installation}, and follow the instructions.
7703 Once installation is complete, you can boot the system that's on your
7704 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7707 @node Building the Installation Image
7708 @subsection Building the Installation Image
7710 @cindex installation image
7711 The installation image described above was built using the @command{guix
7712 system} command, specifically:
7714 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7716 guix system disk-image --image-size=1G gnu/system/install.scm
7719 Have a look at @file{gnu/system/install.scm} in the source tree,
7720 and see also @ref{Invoking guix system} for more information
7721 about the installation image.
7723 @node System Configuration
7724 @section System Configuration
7726 @cindex system configuration
7727 The Guix System Distribution supports a consistent whole-system configuration
7728 mechanism. By that we mean that all aspects of the global system
7729 configuration---such as the available system services, timezone and
7730 locale settings, user accounts---are declared in a single place. Such
7731 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7733 One of the advantages of putting all the system configuration under the
7734 control of Guix is that it supports transactional system upgrades, and
7735 makes it possible to roll back to a previous system instantiation,
7736 should something go wrong with the new one (@pxref{Features}). Another
7737 advantage is that it makes it easy to replicate the exact same configuration
7738 across different machines, or at different points in time, without
7739 having to resort to additional administration tools layered on top of
7740 the own tools of the system.
7741 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7743 This section describes this mechanism. First we focus on the system
7744 administrator's viewpoint---explaining how the system is configured and
7745 instantiated. Then we show how this mechanism can be extended, for
7746 instance to support new system services.
7749 * Using the Configuration System:: Customizing your GNU system.
7750 * operating-system Reference:: Detail of operating-system declarations.
7751 * File Systems:: Configuring file system mounts.
7752 * Mapped Devices:: Block device extra processing.
7753 * User Accounts:: Specifying user accounts.
7754 * Locales:: Language and cultural convention settings.
7755 * Services:: Specifying system services.
7756 * Setuid Programs:: Programs running with root privileges.
7757 * X.509 Certificates:: Authenticating HTTPS servers.
7758 * Name Service Switch:: Configuring libc's name service switch.
7759 * Initial RAM Disk:: Linux-Libre bootstrapping.
7760 * GRUB Configuration:: Configuring the boot loader.
7761 * Invoking guix system:: Instantiating a system configuration.
7762 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7763 * Defining Services:: Adding new service definitions.
7766 @node Using the Configuration System
7767 @subsection Using the Configuration System
7769 The operating system is configured by providing an
7770 @code{operating-system} declaration in a file that can then be passed to
7771 the @command{guix system} command (@pxref{Invoking guix system}). A
7772 simple setup, with the default system services, the default Linux-Libre
7773 kernel, initial RAM disk, and boot loader looks like this:
7775 @findex operating-system
7777 @include os-config-bare-bones.texi
7780 This example should be self-describing. Some of the fields defined
7781 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7782 Others, such as @code{packages} and @code{services}, can be omitted, in
7783 which case they get a default value.
7785 Below we discuss the effect of some of the most important fields
7786 (@pxref{operating-system Reference}, for details about all the available
7787 fields), and how to @dfn{instantiate} the operating system using
7788 @command{guix system}.
7790 @unnumberedsubsubsec Globally-Visible Packages
7792 @vindex %base-packages
7793 The @code{packages} field lists packages that will be globally visible
7794 on the system, for all user accounts---i.e., in every user's @code{PATH}
7795 environment variable---in addition to the per-user profiles
7796 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7797 provides all the tools one would expect for basic user and administrator
7798 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7799 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7800 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7801 packages admin)} module (@pxref{Package Modules}). The
7802 @code{(list package output)} syntax can be used to add a specific output
7806 (use-modules (gnu packages))
7807 (use-modules (gnu packages dns))
7811 (packages (cons (list bind "utils")
7815 @findex specification->package
7816 Referring to packages by variable name, like @var{tcpdump} above, has
7817 the advantage of being unambiguous; it also allows typos and such to be
7818 diagnosed right away as ``unbound variables''. The downside is that one
7819 needs to know which module defines which package, and to augment the
7820 @code{use-package-modules} line accordingly. To avoid that, one can use
7821 the @code{specification->package} procedure of the @code{(gnu packages)}
7822 module, which returns the best package for a given name or name and
7826 (use-modules (gnu packages))
7830 (packages (append (map specification->package
7831 '("tcpdump" "htop" "gnupg@@2.0"))
7835 @unnumberedsubsubsec System Services
7838 @vindex %base-services
7839 The @code{services} field lists @dfn{system services} to be made
7840 available when the system starts (@pxref{Services}).
7841 The @code{operating-system} declaration above specifies that, in
7842 addition to the basic services, we want the @command{lshd} secure shell
7843 daemon listening on port 2222 (@pxref{Networking Services,
7844 @code{lsh-service}}). Under the hood,
7845 @code{lsh-service} arranges so that @code{lshd} is started with the
7846 right command-line options, possibly with supporting configuration files
7847 generated as needed (@pxref{Defining Services}).
7849 @cindex customization, of services
7850 @findex modify-services
7851 Occasionally, instead of using the base services as is, you will want to
7852 customize them. To do this, use @code{modify-services} (@pxref{Service
7853 Reference, @code{modify-services}}) to modify the list.
7855 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7856 (the console log-in) in the @var{%base-services} list (@pxref{Base
7857 Services, @code{%base-services}}). To do that, you can write the
7858 following in your operating system declaration:
7861 (define %my-services
7862 ;; My very own list of services.
7863 (modify-services %base-services
7864 (guix-service-type config =>
7867 (use-substitutes? #f)
7868 (extra-options '("--gc-keep-derivations"))))
7869 (mingetty-service-type config =>
7870 (mingetty-configuration
7871 (inherit config)))))
7875 (services %my-services))
7878 This changes the configuration---i.e., the service parameters---of the
7879 @code{guix-service-type} instance, and that of all the
7880 @code{mingetty-service-type} instances in the @var{%base-services} list.
7881 Observe how this is accomplished: first, we arrange for the original
7882 configuration to be bound to the identifier @code{config} in the
7883 @var{body}, and then we write the @var{body} so that it evaluates to the
7884 desired configuration. In particular, notice how we use @code{inherit}
7885 to create a new configuration which has the same values as the old
7886 configuration, but with a few modifications.
7888 @cindex encrypted disk
7889 The configuration for a typical ``desktop'' usage, with an encrypted
7890 root partition, the X11 display
7891 server, GNOME and Xfce (users can choose which of these desktop
7892 environments to use at the log-in screen by pressing @kbd{F1}), network
7893 management, power management, and more, would look like this:
7896 @include os-config-desktop.texi
7899 A graphical UEFI system with a choice of lightweight window managers
7900 instead of full-blown desktop environments would look like this:
7903 @include os-config-lightweight-desktop.texi
7906 @xref{Desktop Services}, for the exact list of services provided by
7907 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7908 information about the @code{nss-certs} package that is used here.
7910 Again, @var{%desktop-services} is just a list of service objects. If
7911 you want to remove services from there, you can do so using the
7912 procedures for list filtering (@pxref{SRFI-1 Filtering and
7913 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7914 following expression returns a list that contains all the services in
7915 @var{%desktop-services} minus the Avahi service:
7918 (remove (lambda (service)
7919 (eq? (service-kind service) avahi-service-type))
7923 @unnumberedsubsubsec Instantiating the System
7925 Assuming the @code{operating-system} declaration
7926 is stored in the @file{my-system-config.scm}
7927 file, the @command{guix system reconfigure my-system-config.scm} command
7928 instantiates that configuration, and makes it the default GRUB boot
7929 entry (@pxref{Invoking guix system}).
7931 The normal way to change the system configuration is by updating this
7932 file and re-running @command{guix system reconfigure}. One should never
7933 have to touch files in @file{/etc} or to run commands that modify the
7934 system state such as @command{useradd} or @command{grub-install}. In
7935 fact, you must avoid that since that would not only void your warranty
7936 but also prevent you from rolling back to previous versions of your
7937 system, should you ever need to.
7939 @cindex roll-back, of the operating system
7940 Speaking of roll-back, each time you run @command{guix system
7941 reconfigure}, a new @dfn{generation} of the system is created---without
7942 modifying or deleting previous generations. Old system generations get
7943 an entry in the GRUB boot menu, allowing you to boot them in case
7944 something went wrong with the latest generation. Reassuring, no? The
7945 @command{guix system list-generations} command lists the system
7946 generations available on disk. It is also possible to roll back the
7947 system via the commands @command{guix system roll-back} and
7948 @command{guix system switch-generation}.
7950 Although the command @command{guix system reconfigure} will not modify
7951 previous generations, must take care when the current generation is not
7952 the latest (e.g., after invoking @command{guix system roll-back}), since
7953 the operation might overwrite a later generation (@pxref{Invoking guix
7956 @unnumberedsubsubsec The Programming Interface
7958 At the Scheme level, the bulk of an @code{operating-system} declaration
7959 is instantiated with the following monadic procedure (@pxref{The Store
7962 @deffn {Monadic Procedure} operating-system-derivation os
7963 Return a derivation that builds @var{os}, an @code{operating-system}
7964 object (@pxref{Derivations}).
7966 The output of the derivation is a single directory that refers to all
7967 the packages, configuration files, and other supporting files needed to
7968 instantiate @var{os}.
7971 This procedure is provided by the @code{(gnu system)} module. Along
7972 with @code{(gnu services)} (@pxref{Services}), this module contains the
7973 guts of GuixSD. Make sure to visit it!
7976 @node operating-system Reference
7977 @subsection @code{operating-system} Reference
7979 This section summarizes all the options available in
7980 @code{operating-system} declarations (@pxref{Using the Configuration
7983 @deftp {Data Type} operating-system
7984 This is the data type representing an operating system configuration.
7985 By that, we mean all the global system configuration, not per-user
7986 configuration (@pxref{Using the Configuration System}).
7989 @item @code{kernel} (default: @var{linux-libre})
7990 The package object of the operating system kernel to use@footnote{Currently
7991 only the Linux-libre kernel is supported. In the future, it will be
7992 possible to use the GNU@tie{}Hurd.}.
7994 @item @code{kernel-arguments} (default: @code{'()})
7995 List of strings or gexps representing additional arguments to pass on
7996 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7998 @item @code{bootloader}
7999 The system bootloader configuration object. @xref{GRUB Configuration}.
8001 @item @code{initrd} (default: @code{base-initrd})
8003 @cindex initial RAM disk
8004 A two-argument monadic procedure that returns an initial RAM disk for
8005 the Linux kernel. @xref{Initial RAM Disk}.
8007 @item @code{firmware} (default: @var{%base-firmware})
8009 List of firmware packages loadable by the operating system kernel.
8011 The default includes firmware needed for Atheros- and Broadcom-based
8012 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
8013 respectively). @xref{Hardware Considerations}, for more info on
8016 @item @code{host-name}
8019 @item @code{hosts-file}
8021 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
8022 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
8023 Reference Manual}). The default is a file with entries for
8024 @code{localhost} and @var{host-name}.
8026 @item @code{mapped-devices} (default: @code{'()})
8027 A list of mapped devices. @xref{Mapped Devices}.
8029 @item @code{file-systems}
8030 A list of file systems. @xref{File Systems}.
8032 @item @code{swap-devices} (default: @code{'()})
8033 @cindex swap devices
8034 A list of strings identifying devices or files to be used for ``swap
8035 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
8036 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
8037 It is possible to specify a swap file in a file system on a mapped
8038 device, provided that the necessary device mapping and file system are
8039 also specified. @xref{Mapped Devices} and @ref{File Systems}.
8041 @item @code{users} (default: @code{%base-user-accounts})
8042 @itemx @code{groups} (default: @var{%base-groups})
8043 List of user accounts and groups. @xref{User Accounts}.
8045 @item @code{skeletons} (default: @code{(default-skeletons)})
8046 A list target file name/file-like object tuples (@pxref{G-Expressions,
8047 file-like objects}). These are the skeleton files that will be added to
8048 the home directory of newly-created user accounts.
8050 For instance, a valid value may look like this:
8053 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
8054 (".guile" ,(plain-file "guile"
8055 "(use-modules (ice-9 readline))
8056 (activate-readline)")))
8059 @item @code{issue} (default: @var{%default-issue})
8060 A string denoting the contents of the @file{/etc/issue} file, which is
8061 displayed when users log in on a text console.
8063 @item @code{packages} (default: @var{%base-packages})
8064 The set of packages installed in the global profile, which is accessible
8065 at @file{/run/current-system/profile}.
8067 The default set includes core utilities and it is good practice to
8068 install non-core utilities in user profiles (@pxref{Invoking guix
8071 @item @code{timezone}
8072 A timezone identifying string---e.g., @code{"Europe/Paris"}.
8074 You can run the @command{tzselect} command to find out which timezone
8075 string corresponds to your region. Choosing an invalid timezone name
8076 causes @command{guix system} to fail.
8078 @item @code{locale} (default: @code{"en_US.utf8"})
8079 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
8080 Library Reference Manual}). @xref{Locales}, for more information.
8082 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
8083 The list of locale definitions to be compiled and that may be used at
8084 run time. @xref{Locales}.
8086 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
8087 The list of GNU@tie{}libc packages whose locale data and tools are used
8088 to build the locale definitions. @xref{Locales}, for compatibility
8089 considerations that justify this option.
8091 @item @code{name-service-switch} (default: @var{%default-nss})
8092 Configuration of the libc name service switch (NSS)---a
8093 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
8096 @item @code{services} (default: @var{%base-services})
8097 A list of service objects denoting system services. @xref{Services}.
8099 @item @code{pam-services} (default: @code{(base-pam-services)})
8101 @cindex pluggable authentication modules
8102 Linux @dfn{pluggable authentication module} (PAM) services.
8103 @c FIXME: Add xref to PAM services section.
8105 @item @code{setuid-programs} (default: @var{%setuid-programs})
8106 List of string-valued G-expressions denoting setuid programs.
8107 @xref{Setuid Programs}.
8109 @item @code{sudoers-file} (default: @var{%sudoers-specification})
8110 @cindex sudoers file
8111 The contents of the @file{/etc/sudoers} file as a file-like object
8112 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
8114 This file specifies which users can use the @command{sudo} command, what
8115 they are allowed to do, and what privileges they may gain. The default
8116 is that only @code{root} and members of the @code{wheel} group may use
8123 @subsection File Systems
8125 The list of file systems to be mounted is specified in the
8126 @code{file-systems} field of the operating system declaration
8127 (@pxref{Using the Configuration System}). Each file system is declared
8128 using the @code{file-system} form, like this:
8132 (mount-point "/home")
8133 (device "/dev/sda3")
8137 As usual, some of the fields are mandatory---those shown in the example
8138 above---while others can be omitted. These are described below.
8140 @deftp {Data Type} file-system
8141 Objects of this type represent file systems to be mounted. They
8142 contain the following members:
8146 This is a string specifying the type of the file system---e.g.,
8149 @item @code{mount-point}
8150 This designates the place where the file system is to be mounted.
8153 This names the ``source'' of the file system. By default it is the name
8154 of a node under @file{/dev}, but its meaning depends on the @code{title}
8155 field described below.
8157 @item @code{title} (default: @code{'device})
8158 This is a symbol that specifies how the @code{device} field is to be
8161 When it is the symbol @code{device}, then the @code{device} field is
8162 interpreted as a file name; when it is @code{label}, then @code{device}
8163 is interpreted as a partition label name; when it is @code{uuid},
8164 @code{device} is interpreted as a partition unique identifier (UUID).
8166 UUIDs may be converted from their string representation (as shown by the
8167 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8168 @code{uuid} form expects 16-byte UUIDs as defined in
8169 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8170 form of UUID used by the ext2 family of file systems and others, but it
8171 is different from ``UUIDs'' found in FAT file systems, for instance.},
8176 (mount-point "/home")
8179 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8182 The @code{label} and @code{uuid} options offer a way to refer to disk
8183 partitions without having to hard-code their actual device
8184 name@footnote{Note that, while it is tempting to use
8185 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8186 result, this is not recommended: These special device nodes are created
8187 by the udev daemon and may be unavailable at the time the device is
8190 However, when the source of a file system is a mapped device (@pxref{Mapped
8191 Devices}), its @code{device} field @emph{must} refer to the mapped
8192 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8193 @code{title} must be set to @code{'device}. This is required so that
8194 the system knows that mounting the file system depends on having the
8195 corresponding device mapping established.
8197 @item @code{flags} (default: @code{'()})
8198 This is a list of symbols denoting mount flags. Recognized flags
8199 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8200 access to special files), @code{no-suid} (ignore setuid and setgid
8201 bits), and @code{no-exec} (disallow program execution.)
8203 @item @code{options} (default: @code{#f})
8204 This is either @code{#f}, or a string denoting mount options.
8206 @item @code{mount?} (default: @code{#t})
8207 This value indicates whether to automatically mount the file system when
8208 the system is brought up. When set to @code{#f}, the file system gets
8209 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8210 is not automatically mounted.
8212 @item @code{needed-for-boot?} (default: @code{#f})
8213 This Boolean value indicates whether the file system is needed when
8214 booting. If that is true, then the file system is mounted when the
8215 initial RAM disk (initrd) is loaded. This is always the case, for
8216 instance, for the root file system.
8218 @item @code{check?} (default: @code{#t})
8219 This Boolean indicates whether the file system needs to be checked for
8220 errors before being mounted.
8222 @item @code{create-mount-point?} (default: @code{#f})
8223 When true, the mount point is created if it does not exist yet.
8225 @item @code{dependencies} (default: @code{'()})
8226 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8227 representing file systems that must be mounted or mapped devices that
8228 must be opened before (and unmounted or closed after) this one.
8230 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8231 a dependency of @file{/sys/fs/cgroup/cpu} and
8232 @file{/sys/fs/cgroup/memory}.
8234 Another example is a file system that depends on a mapped device, for
8235 example for an encrypted partition (@pxref{Mapped Devices}).
8239 The @code{(gnu system file-systems)} exports the following useful
8242 @defvr {Scheme Variable} %base-file-systems
8243 These are essential file systems that are required on normal systems,
8244 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8245 below.) Operating system declarations should always contain at least
8249 @defvr {Scheme Variable} %pseudo-terminal-file-system
8250 This is the file system to be mounted as @file{/dev/pts}. It supports
8251 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8252 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8253 Manual}). Pseudo-terminals are used by terminal emulators such as
8257 @defvr {Scheme Variable} %shared-memory-file-system
8258 This file system is mounted as @file{/dev/shm} and is used to support
8259 memory sharing across processes (@pxref{Memory-mapped I/O,
8260 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8263 @defvr {Scheme Variable} %immutable-store
8264 This file system performs a read-only ``bind mount'' of
8265 @file{/gnu/store}, making it read-only for all the users including
8266 @code{root}. This prevents against accidental modification by software
8267 running as @code{root} or by system administrators.
8269 The daemon itself is still able to write to the store: it remounts it
8270 read-write in its own ``name space.''
8273 @defvr {Scheme Variable} %binary-format-file-system
8274 The @code{binfmt_misc} file system, which allows handling of arbitrary
8275 executable file types to be delegated to user space. This requires the
8276 @code{binfmt.ko} kernel module to be loaded.
8279 @defvr {Scheme Variable} %fuse-control-file-system
8280 The @code{fusectl} file system, which allows unprivileged users to mount
8281 and unmount user-space FUSE file systems. This requires the
8282 @code{fuse.ko} kernel module to be loaded.
8285 @node Mapped Devices
8286 @subsection Mapped Devices
8288 @cindex device mapping
8289 @cindex mapped devices
8290 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8291 such as a hard disk partition, can be @dfn{mapped} into another device,
8292 usually in @code{/dev/mapper/},
8293 with additional processing over the data that flows through
8294 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8295 concept of a ``mapped device'' and that of a file system: both boil down
8296 to @emph{translating} input/output operations made on a file to
8297 operations on its backing store. Thus, the Hurd implements mapped
8298 devices, like file systems, using the generic @dfn{translator} mechanism
8299 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8300 typical example is encryption device mapping: all writes to the mapped
8301 device are encrypted, and all reads are deciphered, transparently.
8302 Guix extends this notion by considering any device or set of devices that
8303 are @dfn{transformed} in some way to create a new device; for instance,
8304 RAID devices are obtained by @dfn{assembling} several other devices, such
8305 as hard disks or partitions, into a new one that behaves as one partition.
8306 Other examples, not yet implemented, are LVM logical volumes.
8308 Mapped devices are declared using the @code{mapped-device} form,
8309 defined as follows; for examples, see below.
8311 @deftp {Data Type} mapped-device
8312 Objects of this type represent device mappings that will be made when
8313 the system boots up.
8317 This is either a string specifying the name of the block device to be mapped,
8318 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8319 need to be assembled for creating a new one.
8322 This string specifies the name of the resulting mapped device. For
8323 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8324 specifying @code{"my-partition"} leads to the creation of
8325 the @code{"/dev/mapper/my-partition"} device.
8326 For RAID devices of type @code{raid-device-mapping}, the full device name
8327 such as @code{"/dev/md0"} needs to be given.
8330 This must be a @code{mapped-device-kind} object, which specifies how
8331 @var{source} is mapped to @var{target}.
8335 @defvr {Scheme Variable} luks-device-mapping
8336 This defines LUKS block device encryption using the @command{cryptsetup}
8337 command from the package with the same name. It relies on the
8338 @code{dm-crypt} Linux kernel module.
8341 @defvr {Scheme Variable} raid-device-mapping
8342 This defines a RAID device, which is assembled using the @code{mdadm}
8343 command from the package with the same name. It requires a Linux kernel
8344 module for the appropriate RAID level to be loaded, such as @code{raid456}
8345 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8348 @cindex disk encryption
8350 The following example specifies a mapping from @file{/dev/sda3} to
8351 @file{/dev/mapper/home} using LUKS---the
8352 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8353 standard mechanism for disk encryption.
8354 The @file{/dev/mapper/home}
8355 device can then be used as the @code{device} of a @code{file-system}
8356 declaration (@pxref{File Systems}).
8360 (source "/dev/sda3")
8362 (type luks-device-mapping))
8365 Alternatively, to become independent of device numbering, one may obtain
8366 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8370 cryptsetup luksUUID /dev/sda3
8373 and use it as follows:
8377 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8379 (type luks-device-mapping))
8382 @cindex swap encryption
8383 It is also desirable to encrypt swap space, since swap space may contain
8384 sensitive data. One way to accomplish that is to use a swap file in a
8385 file system on a device mapped via LUKS encryption. In this way, the
8386 swap file is encrypted because the entire device is encrypted.
8387 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8389 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8390 may be declared as follows:
8394 (source (list "/dev/sda1" "/dev/sdb1"))
8396 (type raid-device-mapping))
8399 The @file{/dev/md0} device can then be used as the @code{device} of a
8400 @code{file-system} declaration (@pxref{File Systems}).
8401 Note that the RAID level need not be given; it is chosen during the
8402 initial creation and formatting of the RAID device and is determined
8403 automatically later.
8407 @subsection User Accounts
8411 @cindex user accounts
8412 User accounts and groups are entirely managed through the
8413 @code{operating-system} declaration. They are specified with the
8414 @code{user-account} and @code{user-group} forms:
8420 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8422 "video" ;video devices such as webcams
8423 "cdrom")) ;the good ol' CD-ROM
8424 (comment "Bob's sister")
8425 (home-directory "/home/alice"))
8428 When booting or upon completion of @command{guix system reconfigure},
8429 the system ensures that only the user accounts and groups specified in
8430 the @code{operating-system} declaration exist, and with the specified
8431 properties. Thus, account or group creations or modifications made by
8432 directly invoking commands such as @command{useradd} are lost upon
8433 reconfiguration or reboot. This ensures that the system remains exactly
8436 @deftp {Data Type} user-account
8437 Objects of this type represent user accounts. The following members may
8442 The name of the user account.
8446 This is the name (a string) or identifier (a number) of the user group
8447 this account belongs to.
8449 @item @code{supplementary-groups} (default: @code{'()})
8450 Optionally, this can be defined as a list of group names that this
8453 @item @code{uid} (default: @code{#f})
8454 This is the user ID for this account (a number), or @code{#f}. In the
8455 latter case, a number is automatically chosen by the system when the
8458 @item @code{comment} (default: @code{""})
8459 A comment about the account, such as the account owner's full name.
8461 @item @code{home-directory}
8462 This is the name of the home directory for the account.
8464 @item @code{create-home-directory?} (default: @code{#t})
8465 Indicates whether the home directory of this account should be created
8466 if it does not exist yet.
8468 @item @code{shell} (default: Bash)
8469 This is a G-expression denoting the file name of a program to be used as
8470 the shell (@pxref{G-Expressions}).
8472 @item @code{system?} (default: @code{#f})
8473 This Boolean value indicates whether the account is a ``system''
8474 account. System accounts are sometimes treated specially; for instance,
8475 graphical login managers do not list them.
8477 @anchor{user-account-password}
8478 @item @code{password} (default: @code{#f})
8479 You would normally leave this field to @code{#f}, initialize user
8480 passwords as @code{root} with the @command{passwd} command, and then let
8481 users change it with @command{passwd}. Passwords set with
8482 @command{passwd} are of course preserved across reboot and
8485 If you @emph{do} want to have a preset password for an account, then
8486 this field must contain the encrypted password, as a string.
8487 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8488 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8489 Manual}, for information on Guile's @code{crypt} procedure.
8495 User group declarations are even simpler:
8498 (user-group (name "students"))
8501 @deftp {Data Type} user-group
8502 This type is for, well, user groups. There are just a few fields:
8506 The name of the group.
8508 @item @code{id} (default: @code{#f})
8509 The group identifier (a number). If @code{#f}, a new number is
8510 automatically allocated when the group is created.
8512 @item @code{system?} (default: @code{#f})
8513 This Boolean value indicates whether the group is a ``system'' group.
8514 System groups have low numerical IDs.
8516 @item @code{password} (default: @code{#f})
8517 What, user groups can have a password? Well, apparently yes. Unless
8518 @code{#f}, this field specifies the password of the group.
8523 For convenience, a variable lists all the basic user groups one may
8526 @defvr {Scheme Variable} %base-groups
8527 This is the list of basic user groups that users and/or packages expect
8528 to be present on the system. This includes groups such as ``root'',
8529 ``wheel'', and ``users'', as well as groups used to control access to
8530 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8533 @defvr {Scheme Variable} %base-user-accounts
8534 This is the list of basic system accounts that programs may expect to
8535 find on a GNU/Linux system, such as the ``nobody'' account.
8537 Note that the ``root'' account is not included here. It is a
8538 special-case and is automatically added whether or not it is specified.
8545 A @dfn{locale} defines cultural conventions for a particular language
8546 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8547 Reference Manual}). Each locale has a name that typically has the form
8548 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8549 @code{fr_LU.utf8} designates the locale for the French language, with
8550 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8552 @cindex locale definition
8553 Usually, you will want to specify the default locale for the machine
8554 using the @code{locale} field of the @code{operating-system} declaration
8555 (@pxref{operating-system Reference, @code{locale}}).
8557 The selected locale is automatically added to the @dfn{locale
8558 definitions} known to the system if needed, with its codeset inferred
8559 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8560 @code{UTF-8} codeset. Additional locale definitions can be specified in
8561 the @code{locale-definitions} slot of @code{operating-system}---this is
8562 useful, for instance, if the codeset could not be inferred from the
8563 locale name. The default set of locale definitions includes some widely
8564 used locales, but not all the available locales, in order to save space.
8566 For instance, to add the North Frisian locale for Germany, the value of
8570 (cons (locale-definition
8571 (name "fy_DE.utf8") (source "fy_DE"))
8572 %default-locale-definitions)
8575 Likewise, to save space, one might want @code{locale-definitions} to
8576 list only the locales that are actually used, as in:
8579 (list (locale-definition
8580 (name "ja_JP.eucjp") (source "ja_JP")
8581 (charset "EUC-JP")))
8585 The compiled locale definitions are available at
8586 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8587 version, which is the default location where the GNU@tie{}libc provided
8588 by Guix looks for locale data. This can be overridden using the
8589 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8590 @code{LOCPATH} and locale packages}).
8592 The @code{locale-definition} form is provided by the @code{(gnu system
8593 locale)} module. Details are given below.
8595 @deftp {Data Type} locale-definition
8596 This is the data type of a locale definition.
8601 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8602 Reference Manual}, for more information on locale names.
8605 The name of the source for that locale. This is typically the
8606 @code{@var{language}_@var{territory}} part of the locale name.
8608 @item @code{charset} (default: @code{"UTF-8"})
8609 The ``character set'' or ``code set'' for that locale,
8610 @uref{http://www.iana.org/assignments/character-sets, as defined by
8616 @defvr {Scheme Variable} %default-locale-definitions
8617 A list of commonly used UTF-8 locales, used as the default
8618 value of the @code{locale-definitions} field of @code{operating-system}
8622 @cindex normalized codeset in locale names
8623 These locale definitions use the @dfn{normalized codeset} for the part
8624 that follows the dot in the name (@pxref{Using gettextized software,
8625 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8626 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8630 @subsubsection Locale Data Compatibility Considerations
8632 @cindex incompatibility, of locale data
8633 @code{operating-system} declarations provide a @code{locale-libcs} field
8634 to specify the GNU@tie{}libc packages that are used to compile locale
8635 declarations (@pxref{operating-system Reference}). ``Why would I
8636 care?'', you may ask. Well, it turns out that the binary format of
8637 locale data is occasionally incompatible from one libc version to
8640 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8641 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8642 For instance, a program linked against libc version 2.21 is unable to
8643 read locale data produced with libc 2.22; worse, that program
8644 @emph{aborts} instead of simply ignoring the incompatible locale
8645 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8646 the incompatible locale data, which is already an improvement.}.
8647 Similarly, a program linked against libc 2.22 can read most, but not
8648 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8649 data is incompatible); thus calls to @code{setlocale} may fail, but
8650 programs will not abort.
8652 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8653 choose whether and when to upgrade software in their profiles, and might
8654 be using a libc version different from the one the system administrator
8655 used to build the system-wide locale data.
8657 Fortunately, unprivileged users can also install their own locale data
8658 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8659 @code{GUIX_LOCPATH} and locale packages}).
8661 Still, it is best if the system-wide locale data at
8662 @file{/run/current-system/locale} is built for all the libc versions
8663 actually in use on the system, so that all the programs can access
8664 it---this is especially crucial on a multi-user system. To do that, the
8665 administrator can specify several libc packages in the
8666 @code{locale-libcs} field of @code{operating-system}:
8669 (use-package-modules base)
8673 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8676 This example would lead to a system containing locale definitions for
8677 both libc 2.21 and the current version of libc in
8678 @file{/run/current-system/locale}.
8682 @subsection Services
8684 @cindex system services
8685 An important part of preparing an @code{operating-system} declaration is
8686 listing @dfn{system services} and their configuration (@pxref{Using the
8687 Configuration System}). System services are typically daemons launched
8688 when the system boots, or other actions needed at that time---e.g.,
8689 configuring network access.
8691 GuixSD has a broad definition of ``service'' (@pxref{Service
8692 Composition}), but many services are managed by the GNU@tie{}Shepherd
8693 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8694 command allows you to list the available services, show their status,
8695 start and stop them, or do other specific operations (@pxref{Jump
8696 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8702 The above command, run as @code{root}, lists the currently defined
8703 services. The @command{herd doc} command shows a synopsis of the given
8708 Run libc's name service cache daemon (nscd).
8711 The @command{start}, @command{stop}, and @command{restart} sub-commands
8712 have the effect you would expect. For instance, the commands below stop
8713 the nscd service and restart the Xorg display server:
8717 Service nscd has been stopped.
8718 # herd restart xorg-server
8719 Service xorg-server has been stopped.
8720 Service xorg-server has been started.
8723 The following sections document the available services, starting with
8724 the core services, that may be used in an @code{operating-system}
8728 * Base Services:: Essential system services.
8729 * Scheduled Job Execution:: The mcron service.
8730 * Log Rotation:: The rottlog service.
8731 * Networking Services:: Network setup, SSH daemon, etc.
8732 * X Window:: Graphical display.
8733 * Printing Services:: Local and remote printer support.
8734 * Desktop Services:: D-Bus and desktop services.
8735 * Database Services:: SQL databases.
8736 * Mail Services:: IMAP, POP3, SMTP, and all that.
8737 * Messaging Services:: Messaging services.
8738 * Kerberos Services:: Kerberos services.
8739 * Web Services:: Web servers.
8740 * VPN Services:: VPN daemons.
8741 * Network File System:: NFS related services.
8742 * Continuous Integration:: The Cuirass service.
8743 * Power management Services:: The TLP tool.
8744 * Miscellaneous Services:: Other services.
8748 @subsubsection Base Services
8750 The @code{(gnu services base)} module provides definitions for the basic
8751 services that one expects from the system. The services exported by
8752 this module are listed below.
8754 @defvr {Scheme Variable} %base-services
8755 This variable contains a list of basic services (@pxref{Service Types
8756 and Services}, for more information on service objects) one would
8757 expect from the system: a login service (mingetty) on each tty, syslogd,
8758 the libc name service cache daemon (nscd), the udev device manager, and
8761 This is the default value of the @code{services} field of
8762 @code{operating-system} declarations. Usually, when customizing a
8763 system, you will want to append services to @var{%base-services}, like
8767 (cons* (avahi-service) (lsh-service) %base-services)
8771 @defvr {Scheme Variable} special-files-service-type
8772 This is the service that sets up ``special files'' such as
8773 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8775 The value associated with @code{special-files-service-type} services
8776 must be a list of tuples where the first element is the ``special file''
8777 and the second element is its target. By default it is:
8779 @cindex @file{/bin/sh}
8780 @cindex @file{sh}, in @file{/bin}
8782 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8785 @cindex @file{/usr/bin/env}
8786 @cindex @file{env}, in @file{/usr/bin}
8787 If you want to add, say, @code{/usr/bin/env} to your system, you can
8791 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8792 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8795 Since this is part of @code{%base-services}, you can use
8796 @code{modify-services} to customize the set of special files
8797 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8798 to add a special file is @i{via} the @code{extra-special-file} procedure
8802 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8803 Use @var{target} as the ``special file'' @var{file}.
8805 For example, adding the following lines to the @code{services} field of
8806 your operating system declaration leads to a @file{/usr/bin/env}
8810 (extra-special-file "/usr/bin/env"
8811 (file-append coreutils "/bin/env"))
8815 @deffn {Scheme Procedure} host-name-service @var{name}
8816 Return a service that sets the host name to @var{name}.
8819 @deffn {Scheme Procedure} login-service @var{config}
8820 Return a service to run login according to @var{config}, a
8821 @code{<login-configuration>} object, which specifies the message of the day,
8825 @deftp {Data Type} login-configuration
8826 This is the data type representing the configuration of login.
8831 @cindex message of the day
8832 A file-like object containing the ``message of the day''.
8834 @item @code{allow-empty-passwords?} (default: @code{#t})
8835 Allow empty passwords by default so that first-time users can log in when
8836 the 'root' account has just been created.
8841 @deffn {Scheme Procedure} mingetty-service @var{config}
8842 Return a service to run mingetty according to @var{config}, a
8843 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8847 @deftp {Data Type} mingetty-configuration
8848 This is the data type representing the configuration of Mingetty, which
8849 provides the default implementation of virtual console log-in.
8854 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8856 @item @code{auto-login} (default: @code{#f})
8857 When true, this field must be a string denoting the user name under
8858 which the system automatically logs in. When it is @code{#f}, a
8859 user name and password must be entered to log in.
8861 @item @code{login-program} (default: @code{#f})
8862 This must be either @code{#f}, in which case the default log-in program
8863 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8864 the name of the log-in program.
8866 @item @code{login-pause?} (default: @code{#f})
8867 When set to @code{#t} in conjunction with @var{auto-login}, the user
8868 will have to press a key before the log-in shell is launched.
8870 @item @code{mingetty} (default: @var{mingetty})
8871 The Mingetty package to use.
8876 @deffn {Scheme Procedure} agetty-service @var{config}
8877 Return a service to run agetty according to @var{config}, an
8878 @code{<agetty-configuration>} object, which specifies the tty to run,
8882 @deftp {Data Type} agetty-configuration
8883 This is the data type representing the configuration of agetty, which
8884 implements virtual and serial console log-in. See the @code{agetty(8)}
8885 man page for more information.
8890 The name of the console this agetty runs on, as a string---e.g.,
8891 @code{"ttyS0"}. This argument is mandatory.
8893 @item @code{baud-rate} (default: @code{#f})
8894 A string containing a comma-separated list of one or more baud rates, in
8897 @item @code{term} (default: @code{#f})
8898 A string containing the value used for the @code{TERM} environment
8901 @item @code{eight-bits?} (default: @code{#f})
8902 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8905 @item @code{auto-login} (default: @code{#f})
8906 When passed a login name, as a string, the specified user will be logged
8907 in automatically without prompting for their login name or password.
8909 @item @code{no-reset?} (default: @code{#f})
8910 When @code{#t}, don't reset terminal cflags (control modes).
8912 @item @code{host} (default: @code{#f})
8913 This accepts a string containing the "login_host", which will be written
8914 into the @file{/var/run/utmpx} file.
8916 @item @code{remote?} (default: @code{#f})
8917 When set to @code{#t} in conjunction with @var{host}, this will add an
8918 @code{-r} fakehost option to the command line of the login program
8919 specified in @var{login-program}.
8921 @item @code{flow-control?} (default: @code{#f})
8922 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8924 @item @code{no-issue?} (default: @code{#f})
8925 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8926 not be displayed before presenting the login prompt.
8928 @item @code{init-string} (default: @code{#f})
8929 This accepts a string that will be sent to the tty or modem before
8930 sending anything else. It can be used to initialize a modem.
8932 @item @code{no-clear?} (default: @code{#f})
8933 When set to @code{#t}, agetty will not clear the screen before showing
8936 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8937 This must be either a gexp denoting the name of a log-in program, or
8938 unset, in which case the default value is the @command{login} from the
8941 @item @code{local-line} (default: @code{#f})
8942 Control the CLOCAL line flag. This accepts one of three symbols as
8943 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8944 the default value chosen by agetty is @code{'auto}.
8946 @item @code{extract-baud?} (default: @code{#f})
8947 When set to @code{#t}, instruct agetty to try to extract the baud rate
8948 from the status messages produced by certain types of modems.
8950 @item @code{skip-login?} (default: @code{#f})
8951 When set to @code{#t}, do not prompt the user for a login name. This
8952 can be used with @var{login-program} field to use non-standard login
8955 @item @code{no-newline?} (default: @code{#f})
8956 When set to @code{#t}, do not print a newline before printing the
8957 @file{/etc/issue} file.
8959 @c Is this dangerous only when used with login-program, or always?
8960 @item @code{login-options} (default: @code{#f})
8961 This option accepts a string containing options that are passed to the
8962 login program. When used with the @var{login-program}, be aware that a
8963 malicious user could try to enter a login name containing embedded
8964 options that could be parsed by the login program.
8966 @item @code{login-pause} (default: @code{#f})
8967 When set to @code{#t}, wait for any key before showing the login prompt.
8968 This can be used in conjunction with @var{auto-login} to save memory by
8969 lazily spawning shells.
8971 @item @code{chroot} (default: @code{#f})
8972 Change root to the specified directory. This option accepts a directory
8975 @item @code{hangup?} (default: @code{#f})
8976 Use the Linux system call @code{vhangup} to do a virtual hangup of the
8979 @item @code{keep-baud?} (default: @code{#f})
8980 When set to @code{#t}, try to keep the existing baud rate. The baud
8981 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
8984 @item @code{timeout} (default: @code{#f})
8985 When set to an integer value, terminate if no user name could be read
8986 within @var{timeout} seconds.
8988 @item @code{detect-case?} (default: @code{#f})
8989 When set to @code{#t}, turn on support for detecting an uppercase-only
8990 terminal. This setting will detect a login name containing only
8991 uppercase letters as indicating an uppercase-only terminal and turn on
8992 some upper-to-lower case conversions. Note that this will not support
8995 @item @code{wait-cr?} (default: @code{#f})
8996 When set to @code{#t}, wait for the user or modem to send a
8997 carriage-return or linefeed character before displaying
8998 @file{/etc/issue} or login prompt. This is typically used with the
8999 @var{init-string} option.
9001 @item @code{no-hints?} (default: @code{#f})
9002 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
9005 @item @code{no-hostname?} (default: @code{#f})
9006 By default, the hostname is printed. When this option is set to
9007 @code{#t}, no hostname will be shown at all.
9009 @item @code{long-hostname?} (default: @code{#f})
9010 By default, the hostname is only printed until the first dot. When this
9011 option is set to @code{#t}, the fully qualified hostname by
9012 @code{gethostname} or @code{getaddrinfo} is shown.
9014 @item @code{erase-characters} (default: @code{#f})
9015 This option accepts a string of additional characters that should be
9016 interpreted as backspace when the user types their login name.
9018 @item @code{kill-characters} (default: @code{#f})
9019 This option accepts a string that should be interpreted to mean "ignore
9020 all previous characters" (also called a "kill" character) when the types
9023 @item @code{chdir} (default: @code{#f})
9024 This option accepts, as a string, a directory path that will be changed
9027 @item @code{delay} (default: @code{#f})
9028 This options accepts, as an integer, the number of seconds to sleep
9029 before opening the tty and displaying the login prompt.
9031 @item @code{nice} (default: @code{#f})
9032 This option accepts, as an integer, the nice value with which to run the
9033 @command{login} program.
9035 @item @code{extra-options} (default: @code{'()})
9036 This option provides an "escape hatch" for the user to provide arbitrary
9037 command-line arguments to @command{agetty} as a list of strings.
9042 @deffn {Scheme Procedure} kmscon-service-type @var{config}
9043 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
9044 according to @var{config}, a @code{<kmscon-configuration>} object, which
9045 specifies the tty to run, among other things.
9048 @deftp {Data Type} kmscon-configuration
9049 This is the data type representing the configuration of Kmscon, which
9050 implements virtual console log-in.
9054 @item @code{virtual-terminal}
9055 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
9057 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
9058 A gexp denoting the name of the log-in program. The default log-in program is
9059 @command{login} from the Shadow tool suite.
9061 @item @code{login-arguments} (default: @code{'("-p")})
9062 A list of arguments to pass to @command{login}.
9064 @item @code{hardware-acceleration?} (default: #f)
9065 Whether to use hardware acceleration.
9067 @item @code{kmscon} (default: @var{kmscon})
9068 The Kmscon package to use.
9073 @cindex name service cache daemon
9075 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
9076 [#:name-services '()]
9077 Return a service that runs the libc name service cache daemon (nscd) with the
9078 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
9079 Service Switch}, for an example.
9082 @defvr {Scheme Variable} %nscd-default-configuration
9083 This is the default @code{<nscd-configuration>} value (see below) used
9084 by @code{nscd-service}. It uses the caches defined by
9085 @var{%nscd-default-caches}; see below.
9088 @deftp {Data Type} nscd-configuration
9089 This is the data type representing the name service cache daemon (nscd)
9094 @item @code{name-services} (default: @code{'()})
9095 List of packages denoting @dfn{name services} that must be visible to
9096 the nscd---e.g., @code{(list @var{nss-mdns})}.
9098 @item @code{glibc} (default: @var{glibc})
9099 Package object denoting the GNU C Library providing the @command{nscd}
9102 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
9103 Name of the nscd log file. This is where debugging output goes when
9104 @code{debug-level} is strictly positive.
9106 @item @code{debug-level} (default: @code{0})
9107 Integer denoting the debugging levels. Higher numbers mean that more
9108 debugging output is logged.
9110 @item @code{caches} (default: @var{%nscd-default-caches})
9111 List of @code{<nscd-cache>} objects denoting things to be cached; see
9117 @deftp {Data Type} nscd-cache
9118 Data type representing a cache database of nscd and its parameters.
9122 @item @code{database}
9123 This is a symbol representing the name of the database to be cached.
9124 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
9125 @code{services}, which designate the corresponding NSS database
9126 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
9128 @item @code{positive-time-to-live}
9129 @itemx @code{negative-time-to-live} (default: @code{20})
9130 A number representing the number of seconds during which a positive or
9131 negative lookup result remains in cache.
9133 @item @code{check-files?} (default: @code{#t})
9134 Whether to check for updates of the files corresponding to
9137 For instance, when @var{database} is @code{hosts}, setting this flag
9138 instructs nscd to check for updates in @file{/etc/hosts} and to take
9141 @item @code{persistent?} (default: @code{#t})
9142 Whether the cache should be stored persistently on disk.
9144 @item @code{shared?} (default: @code{#t})
9145 Whether the cache should be shared among users.
9147 @item @code{max-database-size} (default: 32@tie{}MiB)
9148 Maximum size in bytes of the database cache.
9150 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9151 @c settings, so leave them out.
9156 @defvr {Scheme Variable} %nscd-default-caches
9157 List of @code{<nscd-cache>} objects used by default by
9158 @code{nscd-configuration} (see above).
9160 It enables persistent and aggressive caching of service and host name
9161 lookups. The latter provides better host name lookup performance,
9162 resilience in the face of unreliable name servers, and also better
9163 privacy---often the result of host name lookups is in local cache, so
9164 external name servers do not even need to be queried.
9167 @anchor{syslog-configuration-type}
9170 @deftp {Data Type} syslog-configuration
9171 This data type represents the configuration of the syslog daemon.
9174 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9175 The syslog daemon to use.
9177 @item @code{config-file} (default: @code{%default-syslog.conf})
9178 The syslog configuration file to use.
9183 @anchor{syslog-service}
9185 @deffn {Scheme Procedure} syslog-service @var{config}
9186 Return a service that runs a syslog daemon according to @var{config}.
9188 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9189 information on the configuration file syntax.
9192 @anchor{guix-configuration-type}
9193 @deftp {Data Type} guix-configuration
9194 This data type represents the configuration of the Guix build daemon.
9195 @xref{Invoking guix-daemon}, for more information.
9198 @item @code{guix} (default: @var{guix})
9199 The Guix package to use.
9201 @item @code{build-group} (default: @code{"guixbuild"})
9202 Name of the group for build user accounts.
9204 @item @code{build-accounts} (default: @code{10})
9205 Number of build user accounts to create.
9207 @item @code{authorize-key?} (default: @code{#t})
9208 @cindex substitutes, authorization thereof
9209 Whether to authorize the substitute keys listed in
9210 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9211 (@pxref{Substitutes}).
9213 @vindex %default-authorized-guix-keys
9214 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9215 The list of authorized key files for archive imports, as a list of
9216 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9217 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9219 @item @code{use-substitutes?} (default: @code{#t})
9220 Whether to use substitutes.
9222 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9223 The list of URLs where to look for substitutes by default.
9225 @item @code{extra-options} (default: @code{'()})
9226 List of extra command-line options for @command{guix-daemon}.
9228 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9229 File where @command{guix-daemon}'s standard output and standard error
9232 @item @code{lsof} (default: @var{lsof})
9233 The lsof package to use.
9235 @item @code{http-proxy} (default: @code{#f})
9236 The HTTP proxy used for downloading fixed-output derivations and
9239 @item @code{tmpdir} (default: @code{#f})
9240 A directory path where the @command{guix-daemon} will perform builds.
9245 @deffn {Scheme Procedure} guix-service @var{config}
9246 Return a service that runs the Guix build daemon according to
9250 @deffn {Scheme Procedure} udev-service [#:udev udev]
9251 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9254 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9255 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9259 @defvr {Scheme Variable} %random-seed-file
9260 This is the name of the file where some random bytes are saved by
9261 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9262 It defaults to @file{/var/lib/random-seed}.
9267 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9268 @cindex keyboard layout
9269 Return a service to load console keymaps from @var{files} using
9270 @command{loadkeys} command. Most likely, you want to load some default
9271 keymap, which can be done like this:
9274 (console-keymap-service "dvorak")
9277 Or, for example, for a Swedish keyboard, you may need to combine
9278 the following keymaps:
9280 (console-keymap-service "se-lat6" "se-fi-lat6")
9283 Also you can specify a full file name (or file names) of your keymap(s).
9284 See @code{man loadkeys} for details.
9290 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9292 Run @var{gpm}, the general-purpose mouse daemon, with the given
9293 command-line @var{options}. GPM allows users to use the mouse in the console,
9294 notably to select, copy, and paste text. The default value of @var{options}
9295 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9297 This service is not part of @var{%base-services}.
9300 @anchor{guix-publish-service-type}
9301 @deffn {Scheme Variable} guix-publish-service-type
9302 This is the service type for @command{guix publish} (@pxref{Invoking
9303 guix publish}). Its value must be a @code{guix-configuration}
9304 object, as described below.
9306 This assumes that @file{/etc/guix} already contains a signing key pair as
9307 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9308 archive}). If that is not the case, the service will fail to start.
9311 @deftp {Data Type} guix-publish-configuration
9312 Data type representing the configuration of the @code{guix publish}
9316 @item @code{guix} (default: @code{guix})
9317 The Guix package to use.
9319 @item @code{port} (default: @code{80})
9320 The TCP port to listen for connections.
9322 @item @code{host} (default: @code{"localhost"})
9323 The host (and thus, network interface) to listen to. Use
9324 @code{"0.0.0.0"} to listen on all the network interfaces.
9326 @item @code{compression-level} (default: @code{3})
9327 The gzip compression level at which substitutes are compressed. Use
9328 @code{0} to disable compression altogether, and @code{9} to get the best
9329 compression ratio at the expense of increased CPU usage.
9331 @item @code{nar-path} (default: @code{"nar"})
9332 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9333 publish, @code{--nar-path}}, for details.
9335 @item @code{cache} (default: @code{#f})
9336 When it is @code{#f}, disable caching and instead generate archives on
9337 demand. Otherwise, this should be the name of a directory---e.g.,
9338 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9339 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9340 @option{--cache}}, for more information on the tradeoffs involved.
9342 @item @code{workers} (default: @code{#f})
9343 When it is an integer, this is the number of worker threads used for
9344 caching; when @code{#f}, the number of processors is used.
9345 @xref{Invoking guix publish, @option{--workers}}, for more information.
9347 @item @code{ttl} (default: @code{#f})
9348 When it is an integer, this denotes the @dfn{time-to-live} of the
9349 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9354 @anchor{rngd-service}
9355 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9356 [#:device "/dev/hwrng"]
9357 Return a service that runs the @command{rngd} program from @var{rng-tools}
9358 to add @var{device} to the kernel's entropy pool. The service will fail if
9359 @var{device} does not exist.
9362 @anchor{pam-limits-service}
9363 @cindex session limits
9366 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9368 Return a service that installs a configuration file for the
9369 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9370 @code{pam_limits} module}. The procedure optionally takes a list of
9371 @code{pam-limits-entry} values, which can be used to specify
9372 @code{ulimit} limits and nice priority limits to user sessions.
9374 The following limits definition sets two hard and soft limits for all
9375 login sessions of users in the @code{realtime} group:
9380 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9381 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9384 The first entry increases the maximum realtime priority for
9385 non-privileged processes; the second entry lifts any restriction of the
9386 maximum address space that can be locked in memory. These settings are
9387 commonly used for real-time audio systems.
9390 @node Scheduled Job Execution
9391 @subsubsection Scheduled Job Execution
9395 @cindex scheduling jobs
9396 The @code{(gnu services mcron)} module provides an interface to
9397 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9398 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9399 Unix @command{cron} daemon; the main difference is that it is
9400 implemented in Guile Scheme, which provides a lot of flexibility when
9401 specifying the scheduling of jobs and their actions.
9403 The example below defines an operating system that runs the
9404 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9405 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9406 well as the @command{mkid} command on behalf of an unprivileged user
9407 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9408 gexps to introduce job definitions that are passed to mcron
9409 (@pxref{G-Expressions}).
9412 (use-modules (guix) (gnu) (gnu services mcron))
9413 (use-package-modules base idutils)
9415 (define updatedb-job
9416 ;; Run 'updatedb' at 3AM every day. Here we write the
9417 ;; job's action as a Scheme procedure.
9418 #~(job '(next-hour '(3))
9420 (execl (string-append #$findutils "/bin/updatedb")
9422 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9424 (define garbage-collector-job
9425 ;; Collect garbage 5 minutes after midnight every day.
9426 ;; The job's action is a shell command.
9427 #~(job "5 0 * * *" ;Vixie cron syntax
9431 ;; Update the index database as user "charlie" at 12:15PM
9432 ;; and 19:15PM. This runs from the user's home directory.
9433 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9434 (string-append #$idutils "/bin/mkid src")
9439 (services (cons (mcron-service (list garbage-collector-job
9445 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9446 for more information on mcron job specifications. Below is the
9447 reference of the mcron service.
9449 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9450 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9451 list of gexps denoting mcron job specifications.
9453 This is a shorthand for:
9455 (service mcron-service-type
9456 (mcron-configuration (mcron mcron) (jobs jobs)))
9460 @defvr {Scheme Variable} mcron-service-type
9461 This is the type of the @code{mcron} service, whose value is an
9462 @code{mcron-configuration} object.
9464 This service type can be the target of a service extension that provides
9465 it additional job specifications (@pxref{Service Composition}). In
9466 other words, it is possible to define services that provide additional
9470 @deftp {Data Type} mcron-configuration
9471 Data type representing the configuration of mcron.
9474 @item @code{mcron} (default: @var{mcron2})
9475 The mcron package to use.
9478 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9479 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9480 specifications,, mcron, GNU@tie{}mcron}).
9486 @subsubsection Log Rotation
9489 @cindex log rotation
9491 Log files such as those found in @file{/var/log} tend to grow endlessly,
9492 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9493 their contents in separate files, possibly compressed. The @code{(gnu
9494 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9495 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9497 The example below defines an operating system that provides log rotation
9498 with the default settings.
9501 (use-modules (guix) (gnu))
9502 (use-service-modules admin mcron)
9503 (use-package-modules base idutils)
9507 (services (cons* (mcron-service)
9508 (service rottlog-service-type)
9512 @defvr {Scheme Variable} rottlog-service-type
9513 This is the type of the Rottlog service, whose value is a
9514 @code{rottlog-configuration} object.
9516 This service type can define mcron jobs (@pxref{Scheduled Job
9517 Execution}) to run the rottlog service.
9520 @deftp {Data Type} rottlog-configuration
9521 Data type representing the configuration of rottlog.
9524 @item @code{rottlog} (default: @code{rottlog})
9525 The Rottlog package to use.
9527 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9528 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9529 rottlog, GNU Rot[t]log Manual}).
9531 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9532 A list of Rottlog period-name/period-config tuples.
9534 For example, taking an example from the Rottlog manual (@pxref{Period
9535 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9539 ("daily" ,(plain-file "daily"
9541 /var/log/apache/* @{
9542 storedir apache-archives
9550 This is a list of gexps where each gexp corresponds to an mcron job
9551 specification (@pxref{Scheduled Job Execution}).
9555 @defvr {Scheme Variable} %default-rotations
9556 Specifies weekly rotation of @var{%rotated-files} and
9557 @code{"/var/log/shepherd.log"}.
9560 @defvr {Scheme Variable} %rotated-files
9561 The list of syslog-controlled files to be rotated. By default it is:
9562 @code{'("/var/log/messages" "/var/log/secure")}.
9565 @node Networking Services
9566 @subsubsection Networking Services
9568 The @code{(gnu services networking)} module provides services to configure
9569 the network interface.
9571 @cindex DHCP, networking service
9572 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9573 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9574 Protocol (DHCP) client, on all the non-loopback network interfaces.
9577 @defvr {Scheme Variable} static-networking-service-type
9578 This is the type for statically-configured network interfaces.
9579 @c TODO Document <static-networking> data structures.
9582 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9583 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9584 Return a service that starts @var{interface} with address @var{ip}. If
9585 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9586 it must be a string specifying the default network gateway.
9588 This procedure can be called several times, one for each network
9589 interface of interest. Behind the scenes what it does is extend
9590 @code{static-networking-service-type} with additional network interfaces
9597 @cindex network management
9598 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9599 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9600 management daemon that aims to simplify wired and wireless networking.
9602 This service adds the @var{wicd} package to the global profile, providing
9603 several commands to interact with the daemon and configure networking:
9604 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9605 and @command{wicd-curses} user interfaces.
9608 @cindex NetworkManager
9610 @defvr {Scheme Variable} network-manager-service-type
9611 This is the service type for the
9612 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9613 service. The value for this service type is a
9614 @code{network-manager-configuration} record.
9617 @deftp {Data Type} network-manager-configuration
9618 Data type representing the configuration of NetworkManager.
9621 @item @code{network-manager} (default: @code{network-manager})
9622 The NetworkManager package to use.
9624 @item @code{dns} (default: @code{"default"})
9625 Processing mode for DNS, which affects how NetworkManager uses the
9626 @code{resolv.conf} configuration file.
9630 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9631 provided by currently active connections.
9634 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9635 using a "split DNS" configuration if you are connected to a VPN, and
9636 then update @code{resolv.conf} to point to the local nameserver.
9639 NetworkManager will not modify @code{resolv.conf}.
9646 @deffn {Scheme Variable} connman-service-type
9647 This is the service type to run @url{https://01.org/connman,Connman},
9648 a network connection manager.
9650 Its value must be an
9651 @code{connman-configuration} record as in this example:
9654 (service connman-service-type
9655 (connman-configuration
9659 See below for details about @code{connman-configuration}.
9662 @deftp {Data Type} connman-configuration
9663 Data Type representing the configuration of connman.
9666 @item @code{connman} (default: @var{connman})
9667 The connman package to use.
9669 @item @code{disable-vpn?} (default: @code{#f})
9670 When true, enable connman's vpn plugin.
9674 @cindex WPA Supplicant
9675 @defvr {Scheme Variable} wpa-supplicant-service-type
9676 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9677 supplicant}, an authentication daemon required to authenticate against
9678 encrypted WiFi or ethernet networks. It is configured to listen for
9681 The value of this service is the @code{wpa-supplicant} package to use.
9682 Thus, it can be instantiated like this:
9685 (use-modules (gnu services networking))
9687 (service wpa-supplicant-service-type)
9692 @cindex real time clock
9693 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9694 [#:servers @var{%ntp-servers}] @
9695 [#:allow-large-adjustment? #f]
9696 Return a service that runs the daemon from @var{ntp}, the
9697 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9698 keep the system clock synchronized with that of @var{servers}.
9699 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9700 make an initial adjustment of more than 1,000 seconds.
9703 @defvr {Scheme Variable} %ntp-servers
9704 List of host names used as the default NTP servers.
9708 @deffn {Scheme variable} inetd-service-type
9709 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9710 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9711 connections on internet sockets, and lazily starts the specified server
9712 program when a connection is made on one of these sockets.
9714 The value of this service is an @code{inetd-configuration} object. The
9715 following example configures the @command{inetd} daemon to provide the
9716 built-in @command{echo} service, as well as an smtp service which
9717 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9718 gateway @code{hostname}:
9723 (inetd-configuration
9727 (socket-type 'stream)
9734 (socket-type 'stream)
9738 (program (file-append openssh "/bin/ssh"))
9740 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9741 "-W" "smtp-server:25" "user@@hostname")))))
9744 See below for more details about @code{inetd-configuration}.
9747 @deftp {Data Type} inetd-configuration
9748 Data type representing the configuration of @command{inetd}.
9751 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9752 The @command{inetd} executable to use.
9754 @item @code{entries} (default: @code{'()})
9755 A list of @command{inetd} service entries. Each entry should be created
9756 by the @code{inetd-entry} constructor.
9760 @deftp {Data Type} inetd-entry
9761 Data type representing an entry in the @command{inetd} configuration.
9762 Each entry corresponds to a socket where @command{inetd} will listen for
9766 @item @code{node} (default: @code{#f})
9767 Optional string, a comma-separated list of local addresses
9768 @command{inetd} should use when listening for this service.
9769 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9770 description of all options.
9772 A string, the name must correspond to an entry in @code{/etc/services}.
9773 @item @code{socket-type}
9774 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9776 @item @code{protocol}
9777 A string, must correspond to an entry in @code{/etc/protocols}.
9778 @item @code{wait?} (default: @code{#t})
9779 Whether @command{inetd} should wait for the server to exit before
9780 listening to new service requests.
9782 A string containing the user (and, optionally, group) name of the user
9783 as whom the server should run. The group name can be specified in a
9784 suffix, separated by a colon or period, i.e. @code{"user"},
9785 @code{"user:group"} or @code{"user.group"}.
9786 @item @code{program} (default: @code{"internal"})
9787 The server program which will serve the requests, or @code{"internal"}
9788 if @command{inetd} should use a built-in service.
9789 @item @code{arguments} (default: @code{'()})
9790 A list strings or file-like objects, which are the server program's
9791 arguments, starting with the zeroth argument, i.e. the name of the
9792 program itself. For @command{inetd}'s internal services, this entry
9793 must be @code{'()} or @code{'("internal")}.
9796 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9797 detailed discussion of each configuration field.
9801 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9802 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9805 The daemon runs as the @code{tor} unprivileged user. It is passed
9806 @var{config-file}, a file-like object, with an additional @code{User tor} line
9807 and lines for hidden services added via @code{tor-hidden-service}. Run
9808 @command{man tor} for information about the configuration file.
9811 @cindex hidden service
9812 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9813 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9814 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9817 '((22 "127.0.0.1:22")
9818 (80 "127.0.0.1:8080"))
9821 In this example, port 22 of the hidden service is mapped to local port 22, and
9822 port 80 is mapped to local port 8080.
9824 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9825 the @file{hostname} file contains the @code{.onion} host name for the hidden
9828 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9829 project's documentation} for more information.
9832 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9833 [#:interface "127.0.0.1"] [#:port 6667] @
9834 [#:extra-settings ""]
9835 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9836 acts as a gateway between IRC and chat networks.
9838 The daemon will listen to the interface corresponding to the IP address
9839 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9840 local clients can connect, whereas @code{0.0.0.0} means that connections can
9841 come from any networking interface.
9843 In addition, @var{extra-settings} specifies a string to append to the
9847 Furthermore, @code{(gnu services ssh)} provides the following services.
9851 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9852 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9853 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9854 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9855 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9856 [#:public-key-authentication? #t] [#:initialize? #t]
9857 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9858 @var{host-key} must designate a file containing the host key, and readable
9861 When @var{daemonic?} is true, @command{lshd} will detach from the
9862 controlling terminal and log its output to syslogd, unless one sets
9863 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9864 depend on existence of syslogd service. When @var{pid-file?} is true,
9865 @command{lshd} writes its PID to the file called @var{pid-file}.
9867 When @var{initialize?} is true, automatically create the seed and host key
9868 upon service activation if they do not exist yet. This may take long and
9869 require interaction.
9871 When @var{initialize?} is false, it is up to the user to initialize the
9872 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9873 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9874 basics,,, lsh, LSH Manual}).
9876 When @var{interfaces} is empty, lshd listens for connections on all the
9877 network interfaces; otherwise, @var{interfaces} must be a list of host names
9880 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9881 passwords, and @var{root-login?} specifies whether to accept log-ins as
9884 The other options should be self-descriptive.
9889 @deffn {Scheme Variable} openssh-service-type
9890 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9891 shell daemon, @command{sshd}. Its value must be an
9892 @code{openssh-configuration} record as in this example:
9895 (service openssh-service-type
9896 (openssh-configuration
9897 (x11-forwarding? #t)
9898 (permit-root-login 'without-password)))
9901 See below for details about @code{openssh-configuration}.
9904 @deftp {Data Type} openssh-configuration
9905 This is the configuration record for OpenSSH's @command{sshd}.
9908 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9909 Name of the file where @command{sshd} writes its PID.
9911 @item @code{port-number} (default: @code{22})
9912 TCP port on which @command{sshd} listens for incoming connections.
9914 @item @code{permit-root-login} (default: @code{#f})
9915 This field determines whether and when to allow logins as root. If
9916 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9917 If it's the symbol @code{'without-password}, then root logins are
9918 permitted but not with password-based authentication.
9920 @item @code{allow-empty-passwords?} (default: @code{#f})
9921 When true, users with empty passwords may log in. When false, they may
9924 @item @code{password-authentication?} (default: @code{#t})
9925 When true, users may log in with their password. When false, they have
9926 other authentication methods.
9928 @item @code{public-key-authentication?} (default: @code{#t})
9929 When true, users may log in using public key authentication. When
9930 false, users have to use other authentication method.
9932 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9933 This is used only by protocol version 2.
9935 @item @code{x11-forwarding?} (default: @code{#f})
9936 When true, forwarding of X11 graphical client connections is
9937 enabled---in other words, @command{ssh} options @option{-X} and
9938 @option{-Y} will work.
9940 @item @code{challenge-response-authentication?} (default: @code{#f})
9941 Specifies whether challenge response authentication is allowed (e.g. via
9944 @item @code{use-pam?} (default: @code{#t})
9945 Enables the Pluggable Authentication Module interface. If set to
9946 @code{#t}, this will enable PAM authentication using
9947 @code{challenge-response-authentication?} and
9948 @code{password-authentication?}, in addition to PAM account and session
9949 module processing for all authentication types.
9951 Because PAM challenge response authentication usually serves an
9952 equivalent role to password authentication, you should disable either
9953 @code{challenge-response-authentication?} or
9954 @code{password-authentication?}.
9956 @item @code{print-last-log?} (default: @code{#t})
9957 Specifies whether @command{sshd} should print the date and time of the
9958 last user login when a user logs in interactively.
9960 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
9961 Configures external subsystems (e.g. file transfer daemon).
9963 This is a list of two-element lists, each of which containing the
9964 subsystem name and a command (with optional arguments) to execute upon
9967 The command @command{internal-sftp} implements an in-process SFTP
9968 server. Alternately, one can specify the @command{sftp-server} command:
9970 (service openssh-service-type
9971 (openssh-configuration
9973 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
9978 @deffn {Scheme Procedure} dropbear-service [@var{config}]
9979 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
9980 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
9983 For example, to specify a Dropbear service listening on port 1234, add
9984 this call to the operating system's @code{services} field:
9987 (dropbear-service (dropbear-configuration
9988 (port-number 1234)))
9992 @deftp {Data Type} dropbear-configuration
9993 This data type represents the configuration of a Dropbear SSH daemon.
9996 @item @code{dropbear} (default: @var{dropbear})
9997 The Dropbear package to use.
9999 @item @code{port-number} (default: 22)
10000 The TCP port where the daemon waits for incoming connections.
10002 @item @code{syslog-output?} (default: @code{#t})
10003 Whether to enable syslog output.
10005 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
10006 File name of the daemon's PID file.
10008 @item @code{root-login?} (default: @code{#f})
10009 Whether to allow @code{root} logins.
10011 @item @code{allow-empty-passwords?} (default: @code{#f})
10012 Whether to allow empty passwords.
10014 @item @code{password-authentication?} (default: @code{#t})
10015 Whether to enable password-based authentication.
10019 @defvr {Scheme Variable} %facebook-host-aliases
10020 This variable contains a string for use in @file{/etc/hosts}
10021 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
10022 line contains a entry that maps a known server name of the Facebook
10023 on-line service---e.g., @code{www.facebook.com}---to the local
10024 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
10026 This variable is typically used in the @code{hosts-file} field of an
10027 @code{operating-system} declaration (@pxref{operating-system Reference,
10028 @file{/etc/hosts}}):
10031 (use-modules (gnu) (guix))
10034 (host-name "mymachine")
10037 ;; Create a /etc/hosts file with aliases for "localhost"
10038 ;; and "mymachine", as well as for Facebook servers.
10039 (plain-file "hosts"
10040 (string-append (local-host-aliases host-name)
10041 %facebook-host-aliases))))
10044 This mechanism can prevent programs running locally, such as Web
10045 browsers, from accessing Facebook.
10048 The @code{(gnu services avahi)} provides the following definition.
10050 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
10051 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
10052 [#:ipv6? #t] [#:wide-area? #f] @
10053 [#:domains-to-browse '()] [#:debug? #f]
10054 Return a service that runs @command{avahi-daemon}, a system-wide
10055 mDNS/DNS-SD responder that allows for service discovery and
10056 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
10057 extends the name service cache daemon (nscd) so that it can resolve
10058 @code{.local} host names using
10059 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
10060 add the @var{avahi} package to the system profile so that commands such as
10061 @command{avahi-browse} are directly usable.
10063 If @var{host-name} is different from @code{#f}, use that as the host name to
10064 publish for this machine; otherwise, use the machine's actual host name.
10066 When @var{publish?} is true, publishing of host names and services is allowed;
10067 in particular, avahi-daemon will publish the machine's host name and IP
10068 address via mDNS on the local network.
10070 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
10072 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
10076 @deffn {Scheme Variable} openvswitch-service-type
10077 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
10078 service, whose value should be an @code{openvswitch-configuration}
10082 @deftp {Data Type} openvswitch-configuration
10083 Data type representing the configuration of Open vSwitch, a multilayer
10084 virtual switch which is designed to enable massive network automation
10085 through programmatic extension.
10088 @item @code{package} (default: @var{openvswitch})
10089 Package object of the Open vSwitch.
10095 @subsubsection X Window
10098 @cindex X Window System
10099 Support for the X Window graphical display system---specifically
10100 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
10101 there is no @code{xorg-service} procedure. Instead, the X server is
10102 started by the @dfn{login manager}, currently SLiM.
10104 @deftp {Data Type} sddm-configuration
10105 This is the data type representing the sddm service configuration.
10108 @item @code{display-server} (default: "x11")
10109 Select display server to use for the greeter. Valid values are "x11"
10112 @item @code{numlock} (default: "on")
10113 Valid values are "on", "off" or "none".
10115 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
10116 Command to run when halting.
10118 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
10119 Command to run when rebooting.
10121 @item @code{theme} (default "maldives")
10122 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
10124 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
10125 Directory to look for themes.
10127 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
10128 Directory to look for faces.
10130 @item @code{default-path} (default "/run/current-system/profile/bin")
10131 Default PATH to use.
10133 @item @code{minimum-uid} (default 1000)
10134 Minimum UID to display in SDDM.
10136 @item @code{maximum-uid} (default 2000)
10137 Maximum UID to display in SDDM
10139 @item @code{remember-last-user?} (default #t)
10140 Remember last user.
10142 @item @code{remember-last-session?} (default #t)
10143 Remember last session.
10145 @item @code{hide-users} (default "")
10146 Usernames to hide from SDDM greeter.
10148 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10149 Users with shells listed will be hidden from the SDDM greeter.
10151 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10152 Script to run before starting a wayland session.
10154 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10155 Directory to look for desktop files starting wayland sessions.
10157 @item @code{xorg-server-path} (default @code{xorg-start-command})
10158 Path to xorg-server.
10160 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10163 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10166 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10167 Script to run after starting xorg-server.
10169 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10170 Script to run before stopping xorg-server.
10172 @item @code{xsession-command} (default: @code{xinitr })
10173 Script to run before starting a X session.
10175 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10176 Directory to look for desktop files starting X sessions.
10178 @item @code{minimum-vt} (default: 7)
10181 @item @code{xserver-arguments} (default "-nolisten tcp")
10182 Arguments to pass to xorg-server.
10184 @item @code{auto-login-user} (default "")
10185 User to use for auto-login.
10187 @item @code{auto-login-session} (default "")
10188 Desktop file to use for auto-login.
10190 @item @code{relogin?} (default #f)
10191 Relogin after logout.
10196 @cindex login manager
10197 @deffn {Scheme Procedure} sddm-service config
10198 Return a service that spawns the SDDM graphical login manager for config of
10199 type @code{<sddm-configuration>}.
10202 (sddm-service (sddm-configuration
10203 (auto-login-user "Alice")
10204 (auto-login-session "xfce.desktop")))
10208 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10209 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10210 [#:theme @var{%default-slim-theme}] @
10211 [#:theme-name @var{%default-slim-theme-name}]
10212 Return a service that spawns the SLiM graphical login manager, which in
10213 turn starts the X display server with @var{startx}, a command as returned by
10214 @code{xorg-start-command}.
10218 SLiM automatically looks for session types described by the @file{.desktop}
10219 files in @file{/run/current-system/profile/share/xsessions} and allows users
10220 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10221 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10222 adding them to the system-wide set of packages automatically makes them
10223 available at the log-in screen.
10225 In addition, @file{~/.xsession} files are honored. When available,
10226 @file{~/.xsession} must be an executable that starts a window manager
10227 and/or other X clients.
10229 When @var{allow-empty-passwords?} is true, allow logins with an empty
10230 password. When @var{auto-login?} is true, log in automatically as
10231 @var{default-user}.
10233 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10234 @var{theme} must be a gexp denoting the name of a directory containing the
10235 theme to use. In that case, @var{theme-name} specifies the name of the
10239 @defvr {Scheme Variable} %default-theme
10240 @defvrx {Scheme Variable} %default-theme-name
10241 The G-Expression denoting the default SLiM theme and its name.
10244 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10245 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10246 Return a derivation that builds a @var{guile} script to start the X server
10247 from @var{xorg-server}. @var{configuration-file} is the server configuration
10248 file or a derivation that builds it; when omitted, the result of
10249 @code{xorg-configuration-file} is used.
10251 Usually the X server is started by a login manager.
10254 @deffn {Scheme Procedure} xorg-configuration-file @
10255 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10256 Return a configuration file for the Xorg server containing search paths for
10257 all the common drivers.
10259 @var{drivers} must be either the empty list, in which case Xorg chooses a
10260 graphics driver automatically, or a list of driver names that will be tried in
10261 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10263 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10264 appropriate screen resolution; otherwise, it must be a list of
10265 resolutions---e.g., @code{((1024 768) (640 480))}.
10267 Last, @var{extra-config} is a list of strings or objects appended to the
10268 @code{text-file*} argument list. It is used to pass extra text to be added
10269 verbatim to the configuration file.
10272 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10273 Add @var{package}, a package for a screen-locker or screen-saver whose
10274 command is @var{program}, to the set of setuid programs and add a PAM entry
10275 for it. For example:
10278 (screen-locker-service xlockmore "xlock")
10281 makes the good ol' XlockMore usable.
10285 @node Printing Services
10286 @subsubsection Printing Services
10288 @cindex printer support with CUPS
10289 The @code{(gnu services cups)} module provides a Guix service definition
10290 for the CUPS printing service. To add printer support to a GuixSD
10291 system, add a @code{cups-service} to the operating system definition:
10293 @deffn {Scheme Variable} cups-service-type
10294 The service type for the CUPS print server. Its value should be a valid
10295 CUPS configuration (see below). To use the default settings, simply
10298 (service cups-service-type)
10302 The CUPS configuration controls the basic things about your CUPS
10303 installation: what interfaces it listens on, what to do if a print job
10304 fails, how much logging to do, and so on. To actually add a printer,
10305 you have to visit the @url{http://localhost:631} URL, or use a tool such
10306 as GNOME's printer configuration services. By default, configuring a
10307 CUPS service will generate a self-signed certificate if needed, for
10308 secure connections to the print server.
10310 Suppose you want to enable the Web interface of CUPS and also add
10311 support for HP printers @i{via} the @code{hplip} package. You can do
10312 that directly, like this (you need to use the @code{(gnu packages cups)}
10316 (service cups-service-type
10317 (cups-configuration
10318 (web-interface? #t)
10320 (list cups-filters hplip))))
10323 The available configuration parameters follow. Each parameter
10324 definition is preceded by its type; for example, @samp{string-list foo}
10325 indicates that the @code{foo} parameter should be specified as a list of
10326 strings. There is also a way to specify the configuration as a string,
10327 if you have an old @code{cupsd.conf} file that you want to port over
10328 from some other system; see the end for more details.
10330 @c The following documentation was initially generated by
10331 @c (generate-documentation) in (gnu services cups). Manually maintained
10332 @c documentation is better, so we shouldn't hesitate to edit below as
10333 @c needed. However if the change you want to make to this documentation
10334 @c can be done in an automated way, it's probably easier to change
10335 @c (generate-documentation) than to make it below and have to deal with
10336 @c the churn as CUPS updates.
10339 Available @code{cups-configuration} fields are:
10341 @deftypevr {@code{cups-configuration} parameter} package cups
10345 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10346 Drivers and other extensions to the CUPS package.
10349 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10350 Configuration of where to write logs, what directories to use for print
10351 spools, and related privileged configuration parameters.
10353 Available @code{files-configuration} fields are:
10355 @deftypevr {@code{files-configuration} parameter} log-location access-log
10356 Defines the access log filename. Specifying a blank filename disables
10357 access log generation. The value @code{stderr} causes log entries to be
10358 sent to the standard error file when the scheduler is running in the
10359 foreground, or to the system log daemon when run in the background. The
10360 value @code{syslog} causes log entries to be sent to the system log
10361 daemon. The server name may be included in filenames using the string
10362 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10364 Defaults to @samp{"/var/log/cups/access_log"}.
10367 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10368 Where CUPS should cache data.
10370 Defaults to @samp{"/var/cache/cups"}.
10373 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10374 Specifies the permissions for all configuration files that the scheduler
10377 Note that the permissions for the printers.conf file are currently
10378 masked to only allow access from the scheduler user (typically root).
10379 This is done because printer device URIs sometimes contain sensitive
10380 authentication information that should not be generally known on the
10381 system. There is no way to disable this security feature.
10383 Defaults to @samp{"0640"}.
10386 @deftypevr {@code{files-configuration} parameter} log-location error-log
10387 Defines the error log filename. Specifying a blank filename disables
10388 access log generation. The value @code{stderr} causes log entries to be
10389 sent to the standard error file when the scheduler is running in the
10390 foreground, or to the system log daemon when run in the background. The
10391 value @code{syslog} causes log entries to be sent to the system log
10392 daemon. The server name may be included in filenames using the string
10393 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10395 Defaults to @samp{"/var/log/cups/error_log"}.
10398 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10399 Specifies which errors are fatal, causing the scheduler to exit. The
10404 No errors are fatal.
10407 All of the errors below are fatal.
10410 Browsing initialization errors are fatal, for example failed connections
10411 to the DNS-SD daemon.
10414 Configuration file syntax errors are fatal.
10417 Listen or Port errors are fatal, except for IPv6 failures on the
10418 loopback or @code{any} addresses.
10421 Log file creation or write errors are fatal.
10424 Bad startup file permissions are fatal, for example shared TLS
10425 certificate and key files with world-read permissions.
10428 Defaults to @samp{"all -browse"}.
10431 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10432 Specifies whether the file pseudo-device can be used for new printer
10433 queues. The URI @uref{file:///dev/null} is always allowed.
10435 Defaults to @samp{#f}.
10438 @deftypevr {@code{files-configuration} parameter} string group
10439 Specifies the group name or ID that will be used when executing external
10442 Defaults to @samp{"lp"}.
10445 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10446 Specifies the permissions for all log files that the scheduler writes.
10448 Defaults to @samp{"0644"}.
10451 @deftypevr {@code{files-configuration} parameter} log-location page-log
10452 Defines the page log filename. Specifying a blank filename disables
10453 access log generation. The value @code{stderr} causes log entries to be
10454 sent to the standard error file when the scheduler is running in the
10455 foreground, or to the system log daemon when run in the background. The
10456 value @code{syslog} causes log entries to be sent to the system log
10457 daemon. The server name may be included in filenames using the string
10458 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10460 Defaults to @samp{"/var/log/cups/page_log"}.
10463 @deftypevr {@code{files-configuration} parameter} string remote-root
10464 Specifies the username that is associated with unauthenticated accesses
10465 by clients claiming to be the root user. The default is @code{remroot}.
10467 Defaults to @samp{"remroot"}.
10470 @deftypevr {@code{files-configuration} parameter} file-name request-root
10471 Specifies the directory that contains print jobs and other HTTP request
10474 Defaults to @samp{"/var/spool/cups"}.
10477 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10478 Specifies the level of security sandboxing that is applied to print
10479 filters, backends, and other child processes of the scheduler; either
10480 @code{relaxed} or @code{strict}. This directive is currently only
10481 used/supported on macOS.
10483 Defaults to @samp{strict}.
10486 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10487 Specifies the location of TLS certificates and private keys. CUPS will
10488 look for public and private keys in this directory: a @code{.crt} files
10489 for PEM-encoded certificates and corresponding @code{.key} files for
10490 PEM-encoded private keys.
10492 Defaults to @samp{"/etc/cups/ssl"}.
10495 @deftypevr {@code{files-configuration} parameter} file-name server-root
10496 Specifies the directory containing the server configuration files.
10498 Defaults to @samp{"/etc/cups"}.
10501 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10502 Specifies whether the scheduler calls fsync(2) after writing
10503 configuration or state files.
10505 Defaults to @samp{#f}.
10508 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10509 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10512 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10513 Specifies the directory where temporary files are stored.
10515 Defaults to @samp{"/var/spool/cups/tmp"}.
10518 @deftypevr {@code{files-configuration} parameter} string user
10519 Specifies the user name or ID that is used when running external
10522 Defaults to @samp{"lp"}.
10526 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10527 Specifies the logging level for the AccessLog file. The @code{config}
10528 level logs when printers and classes are added, deleted, or modified and
10529 when configuration files are accessed or updated. The @code{actions}
10530 level logs when print jobs are submitted, held, released, modified, or
10531 canceled, and any of the conditions for @code{config}. The @code{all}
10532 level logs all requests.
10534 Defaults to @samp{actions}.
10537 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10538 Specifies whether to purge job history data automatically when it is no
10539 longer required for quotas.
10541 Defaults to @samp{#f}.
10544 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10545 Specifies which protocols to use for local printer sharing.
10547 Defaults to @samp{dnssd}.
10550 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10551 Specifies whether the CUPS web interface is advertised.
10553 Defaults to @samp{#f}.
10556 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10557 Specifies whether shared printers are advertised.
10559 Defaults to @samp{#f}.
10562 @deftypevr {@code{cups-configuration} parameter} string classification
10563 Specifies the security classification of the server. Any valid banner
10564 name can be used, including "classified", "confidential", "secret",
10565 "topsecret", and "unclassified", or the banner can be omitted to disable
10566 secure printing functions.
10568 Defaults to @samp{""}.
10571 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10572 Specifies whether users may override the classification (cover page) of
10573 individual print jobs using the @code{job-sheets} option.
10575 Defaults to @samp{#f}.
10578 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10579 Specifies the default type of authentication to use.
10581 Defaults to @samp{Basic}.
10584 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10585 Specifies whether encryption will be used for authenticated requests.
10587 Defaults to @samp{Required}.
10590 @deftypevr {@code{cups-configuration} parameter} string default-language
10591 Specifies the default language to use for text and web content.
10593 Defaults to @samp{"en"}.
10596 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10597 Specifies the default paper size for new print queues. @samp{"Auto"}
10598 uses a locale-specific default, while @samp{"None"} specifies there is
10599 no default paper size. Specific size names are typically
10600 @samp{"Letter"} or @samp{"A4"}.
10602 Defaults to @samp{"Auto"}.
10605 @deftypevr {@code{cups-configuration} parameter} string default-policy
10606 Specifies the default access policy to use.
10608 Defaults to @samp{"default"}.
10611 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10612 Specifies whether local printers are shared by default.
10614 Defaults to @samp{#t}.
10617 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10618 Specifies the delay for updating of configuration and state files, in
10619 seconds. A value of 0 causes the update to happen as soon as possible,
10620 typically within a few milliseconds.
10622 Defaults to @samp{30}.
10625 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10626 Specifies what to do when an error occurs. Possible values are
10627 @code{abort-job}, which will discard the failed print job;
10628 @code{retry-job}, which will retry the job at a later time;
10629 @code{retry-this-job}, which retries the failed job immediately; and
10630 @code{stop-printer}, which stops the printer.
10632 Defaults to @samp{stop-printer}.
10635 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10636 Specifies the maximum cost of filters that are run concurrently, which
10637 can be used to minimize disk, memory, and CPU resource problems. A
10638 limit of 0 disables filter limiting. An average print to a
10639 non-PostScript printer needs a filter limit of about 200. A PostScript
10640 printer needs about half that (100). Setting the limit below these
10641 thresholds will effectively limit the scheduler to printing a single job
10644 Defaults to @samp{0}.
10647 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10648 Specifies the scheduling priority of filters that are run to print a
10649 job. The nice value ranges from 0, the highest priority, to 19, the
10652 Defaults to @samp{0}.
10655 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10656 Specifies whether to do reverse lookups on connecting clients. The
10657 @code{double} setting causes @code{cupsd} to verify that the hostname
10658 resolved from the address matches one of the addresses returned for that
10659 hostname. Double lookups also prevent clients with unregistered
10660 addresses from connecting to your server. Only set this option to
10661 @code{#t} or @code{double} if absolutely required.
10663 Defaults to @samp{#f}.
10666 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10667 Specifies the number of seconds to wait before killing the filters and
10668 backend associated with a canceled or held job.
10670 Defaults to @samp{30}.
10673 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10674 Specifies the interval between retries of jobs in seconds. This is
10675 typically used for fax queues but can also be used with normal print
10676 queues whose error policy is @code{retry-job} or
10677 @code{retry-current-job}.
10679 Defaults to @samp{30}.
10682 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10683 Specifies the number of retries that are done for jobs. This is
10684 typically used for fax queues but can also be used with normal print
10685 queues whose error policy is @code{retry-job} or
10686 @code{retry-current-job}.
10688 Defaults to @samp{5}.
10691 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10692 Specifies whether to support HTTP keep-alive connections.
10694 Defaults to @samp{#t}.
10697 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10698 Specifies how long an idle client connection remains open, in seconds.
10700 Defaults to @samp{30}.
10703 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10704 Specifies the maximum size of print files, IPP requests, and HTML form
10705 data. A limit of 0 disables the limit check.
10707 Defaults to @samp{0}.
10710 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10711 Listens on the specified interfaces for connections. Valid values are
10712 of the form @var{address}:@var{port}, where @var{address} is either an
10713 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10714 indicate all addresses. Values can also be file names of local UNIX
10715 domain sockets. The Listen directive is similar to the Port directive
10716 but allows you to restrict access to specific interfaces or networks.
10719 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10720 Specifies the number of pending connections that will be allowed. This
10721 normally only affects very busy servers that have reached the MaxClients
10722 limit, but can also be triggered by large numbers of simultaneous
10723 connections. When the limit is reached, the operating system will
10724 refuse additional connections until the scheduler can accept the pending
10727 Defaults to @samp{128}.
10730 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10731 Specifies a set of additional access controls.
10733 Available @code{location-access-controls} fields are:
10735 @deftypevr {@code{location-access-controls} parameter} file-name path
10736 Specifies the URI path to which the access control applies.
10739 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10740 Access controls for all access to this path, in the same format as the
10741 @code{access-controls} of @code{operation-access-control}.
10743 Defaults to @samp{()}.
10746 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10747 Access controls for method-specific access to this path.
10749 Defaults to @samp{()}.
10751 Available @code{method-access-controls} fields are:
10753 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10754 If @code{#t}, apply access controls to all methods except the listed
10755 methods. Otherwise apply to only the listed methods.
10757 Defaults to @samp{#f}.
10760 @deftypevr {@code{method-access-controls} parameter} method-list methods
10761 Methods to which this access control applies.
10763 Defaults to @samp{()}.
10766 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10767 Access control directives, as a list of strings. Each string should be
10768 one directive, such as "Order allow,deny".
10770 Defaults to @samp{()}.
10775 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10776 Specifies the number of debugging messages that are retained for logging
10777 if an error occurs in a print job. Debug messages are logged regardless
10778 of the LogLevel setting.
10780 Defaults to @samp{100}.
10783 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10784 Specifies the level of logging for the ErrorLog file. The value
10785 @code{none} stops all logging while @code{debug2} logs everything.
10787 Defaults to @samp{info}.
10790 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10791 Specifies the format of the date and time in the log files. The value
10792 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10794 Defaults to @samp{standard}.
10797 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10798 Specifies the maximum number of simultaneous clients that are allowed by
10801 Defaults to @samp{100}.
10804 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10805 Specifies the maximum number of simultaneous clients that are allowed
10806 from a single address.
10808 Defaults to @samp{100}.
10811 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10812 Specifies the maximum number of copies that a user can print of each
10815 Defaults to @samp{9999}.
10818 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10819 Specifies the maximum time a job may remain in the @code{indefinite}
10820 hold state before it is canceled. A value of 0 disables cancellation of
10823 Defaults to @samp{0}.
10826 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10827 Specifies the maximum number of simultaneous jobs that are allowed. Set
10828 to 0 to allow an unlimited number of jobs.
10830 Defaults to @samp{500}.
10833 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10834 Specifies the maximum number of simultaneous jobs that are allowed per
10835 printer. A value of 0 allows up to MaxJobs jobs per printer.
10837 Defaults to @samp{0}.
10840 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10841 Specifies the maximum number of simultaneous jobs that are allowed per
10842 user. A value of 0 allows up to MaxJobs jobs per user.
10844 Defaults to @samp{0}.
10847 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10848 Specifies the maximum time a job may take to print before it is
10849 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10851 Defaults to @samp{10800}.
10854 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10855 Specifies the maximum size of the log files before they are rotated, in
10856 bytes. The value 0 disables log rotation.
10858 Defaults to @samp{1048576}.
10861 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10862 Specifies the maximum amount of time to allow between files in a
10863 multiple file print job, in seconds.
10865 Defaults to @samp{300}.
10868 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10869 Specifies the format of PageLog lines. Sequences beginning with percent
10870 (@samp{%}) characters are replaced with the corresponding information,
10871 while all other characters are copied literally. The following percent
10872 sequences are recognized:
10876 insert a single percent character
10879 insert the value of the specified IPP attribute
10882 insert the number of copies for the current page
10885 insert the current page number
10888 insert the current date and time in common log format
10894 insert the printer name
10897 insert the username
10900 A value of the empty string disables page logging. The string @code{%p
10901 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10902 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10905 Defaults to @samp{""}.
10908 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10909 Passes the specified environment variable(s) to child processes; a list
10912 Defaults to @samp{()}.
10915 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10916 Specifies named access control policies.
10918 Available @code{policy-configuration} fields are:
10920 @deftypevr {@code{policy-configuration} parameter} string name
10921 Name of the policy.
10924 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10925 Specifies an access list for a job's private values. @code{@@ACL} maps
10926 to the printer's requesting-user-name-allowed or
10927 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10928 owner. @code{@@SYSTEM} maps to the groups listed for the
10929 @code{system-group} field of the @code{files-config} configuration,
10930 which is reified into the @code{cups-files.conf(5)} file. Other
10931 possible elements of the access list include specific user names, and
10932 @code{@@@var{group}} to indicate members of a specific group. The
10933 access list may also be simply @code{all} or @code{default}.
10935 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10938 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10939 Specifies the list of job values to make private, or @code{all},
10940 @code{default}, or @code{none}.
10942 Defaults to @samp{"job-name job-originating-host-name
10943 job-originating-user-name phone"}.
10946 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10947 Specifies an access list for a subscription's private values.
10948 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10949 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10950 owner. @code{@@SYSTEM} maps to the groups listed for the
10951 @code{system-group} field of the @code{files-config} configuration,
10952 which is reified into the @code{cups-files.conf(5)} file. Other
10953 possible elements of the access list include specific user names, and
10954 @code{@@@var{group}} to indicate members of a specific group. The
10955 access list may also be simply @code{all} or @code{default}.
10957 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10960 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
10961 Specifies the list of job values to make private, or @code{all},
10962 @code{default}, or @code{none}.
10964 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
10965 notify-subscriber-user-name notify-user-data"}.
10968 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
10969 Access control by IPP operation.
10971 Defaults to @samp{()}.
10975 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
10976 Specifies whether job files (documents) are preserved after a job is
10977 printed. If a numeric value is specified, job files are preserved for
10978 the indicated number of seconds after printing. Otherwise a boolean
10979 value applies indefinitely.
10981 Defaults to @samp{86400}.
10984 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
10985 Specifies whether the job history is preserved after a job is printed.
10986 If a numeric value is specified, the job history is preserved for the
10987 indicated number of seconds after printing. If @code{#t}, the job
10988 history is preserved until the MaxJobs limit is reached.
10990 Defaults to @samp{#t}.
10993 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
10994 Specifies the amount of time to wait for job completion before
10995 restarting the scheduler.
10997 Defaults to @samp{30}.
11000 @deftypevr {@code{cups-configuration} parameter} string rip-cache
11001 Specifies the maximum amount of memory to use when converting documents
11002 into bitmaps for a printer.
11004 Defaults to @samp{"128m"}.
11007 @deftypevr {@code{cups-configuration} parameter} string server-admin
11008 Specifies the email address of the server administrator.
11010 Defaults to @samp{"root@@localhost.localdomain"}.
11013 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
11014 The ServerAlias directive is used for HTTP Host header validation when
11015 clients connect to the scheduler from external interfaces. Using the
11016 special name @code{*} can expose your system to known browser-based DNS
11017 rebinding attacks, even when accessing sites through a firewall. If the
11018 auto-discovery of alternate names does not work, we recommend listing
11019 each alternate name with a ServerAlias directive instead of using
11022 Defaults to @samp{*}.
11025 @deftypevr {@code{cups-configuration} parameter} string server-name
11026 Specifies the fully-qualified host name of the server.
11028 Defaults to @samp{"localhost"}.
11031 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
11032 Specifies what information is included in the Server header of HTTP
11033 responses. @code{None} disables the Server header. @code{ProductOnly}
11034 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
11035 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
11036 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
11037 the output of the @code{uname} command. @code{Full} reports @code{CUPS
11038 2.0.0 (@var{uname}) IPP/2.0}.
11040 Defaults to @samp{Minimal}.
11043 @deftypevr {@code{cups-configuration} parameter} string set-env
11044 Set the specified environment variable to be passed to child processes.
11046 Defaults to @samp{"variable value"}.
11049 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
11050 Listens on the specified interfaces for encrypted connections. Valid
11051 values are of the form @var{address}:@var{port}, where @var{address} is
11052 either an IPv6 address enclosed in brackets, an IPv4 address, or
11053 @code{*} to indicate all addresses.
11055 Defaults to @samp{()}.
11058 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
11059 Sets encryption options. By default, CUPS only supports encryption
11060 using TLS v1.0 or higher using known secure cipher suites. The
11061 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
11062 required for some older clients that do not implement newer ones. The
11063 @code{AllowSSL3} option enables SSL v3.0, which is required for some
11064 older clients that do not support TLS v1.0.
11066 Defaults to @samp{()}.
11069 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
11070 Specifies whether the scheduler requires clients to strictly adhere to
11071 the IPP specifications.
11073 Defaults to @samp{#f}.
11076 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
11077 Specifies the HTTP request timeout, in seconds.
11079 Defaults to @samp{300}.
11083 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
11084 Specifies whether the web interface is enabled.
11086 Defaults to @samp{#f}.
11089 At this point you're probably thinking ``oh dear, Guix manual, I like
11090 you but you can stop already with the configuration options''. Indeed.
11091 However, one more point: it could be that you have an existing
11092 @code{cupsd.conf} that you want to use. In that case, you can pass an
11093 @code{opaque-cups-configuration} as the configuration of a
11094 @code{cups-service-type}.
11096 Available @code{opaque-cups-configuration} fields are:
11098 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
11102 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
11103 The contents of the @code{cupsd.conf}, as a string.
11106 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
11107 The contents of the @code{cups-files.conf} file, as a string.
11110 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
11111 strings of the same name, you could instantiate a CUPS service like
11115 (service cups-service-type
11116 (opaque-cups-configuration
11117 (cupsd.conf cupsd.conf)
11118 (cups-files.conf cups-files.conf)))
11122 @node Desktop Services
11123 @subsubsection Desktop Services
11125 The @code{(gnu services desktop)} module provides services that are
11126 usually useful in the context of a ``desktop'' setup---that is, on a
11127 machine running a graphical display server, possibly with graphical user
11128 interfaces, etc. It also defines services that provide specific desktop
11129 environments like GNOME and XFCE.
11131 To simplify things, the module defines a variable containing the set of
11132 services that users typically expect on a machine with a graphical
11133 environment and networking:
11135 @defvr {Scheme Variable} %desktop-services
11136 This is a list of services that builds upon @var{%base-services} and
11137 adds or adjusts services for a typical ``desktop'' setup.
11139 In particular, it adds a graphical login manager (@pxref{X Window,
11140 @code{slim-service}}), screen lockers,
11141 a network management tool (@pxref{Networking
11142 Services, @code{wicd-service}}), energy and color management services,
11143 the @code{elogind} login and seat manager, the Polkit privilege service,
11144 the GeoClue location service, an NTP client (@pxref{Networking
11145 Services}), the Avahi daemon, and has the name service switch service
11146 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11150 The @var{%desktop-services} variable can be used as the @code{services}
11151 field of an @code{operating-system} declaration (@pxref{operating-system
11152 Reference, @code{services}}).
11154 Additionally, the @code{gnome-desktop-service} and
11155 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11156 system. To ``add GNOME'' means that system-level services like the
11157 backlight adjustment helpers and the power management utilities are
11158 added to the system, extending @code{polkit} and @code{dbus}
11159 appropriately, allowing GNOME to operate with elevated privileges on a
11160 limited number of special-purpose system interfaces. Additionally,
11161 adding a service made by @code{gnome-desktop-service} adds the GNOME
11162 metapackage to the system profile. Likewise, adding the XFCE service
11163 not only adds the @code{xfce} metapackage to the system profile, but it
11164 also gives the Thunar file manager the ability to open a ``root-mode''
11165 file management window, if the user authenticates using the
11166 administrator's password via the standard polkit graphical interface.
11168 @deffn {Scheme Procedure} gnome-desktop-service
11169 Return a service that adds the @code{gnome} package to the system
11170 profile, and extends polkit with the actions from
11171 @code{gnome-settings-daemon}.
11174 @deffn {Scheme Procedure} xfce-desktop-service
11175 Return a service that adds the @code{xfce} package to the system profile,
11176 and extends polkit with the ability for @code{thunar} to manipulate the
11177 file system as root from within a user session, after the user has
11178 authenticated with the administrator's password.
11181 Because the GNOME and XFCE desktop services pull in so many packages,
11182 the default @code{%desktop-services} variable doesn't include either of
11183 them by default. To add GNOME or XFCE, just @code{cons} them onto
11184 @code{%desktop-services} in the @code{services} field of your
11185 @code{operating-system}:
11188 (use-modules (gnu))
11189 (use-service-modules desktop)
11192 ;; cons* adds items to the list given as its last argument.
11193 (services (cons* (gnome-desktop-service)
11194 (xfce-desktop-service)
11195 %desktop-services))
11199 These desktop environments will then be available as options in the
11200 graphical login window.
11202 The actual service definitions included in @code{%desktop-services} and
11203 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11204 are described below.
11206 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11207 Return a service that runs the ``system bus'', using @var{dbus}, with
11208 support for @var{services}.
11210 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11211 facility. Its system bus is used to allow system services to communicate
11212 and to be notified of system-wide events.
11214 @var{services} must be a list of packages that provide an
11215 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11216 and policy files. For example, to allow avahi-daemon to use the system bus,
11217 @var{services} must be equal to @code{(list avahi)}.
11220 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11221 Return a service that runs the @code{elogind} login and
11222 seat management daemon. @uref{https://github.com/andywingo/elogind,
11223 Elogind} exposes a D-Bus interface that can be used to know which users
11224 are logged in, know what kind of sessions they have open, suspend the
11225 system, inhibit system suspend, reboot the system, and other tasks.
11227 Elogind handles most system-level power events for a computer, for
11228 example suspending the system when a lid is closed, or shutting it down
11229 when the power button is pressed.
11231 The @var{config} keyword argument specifies the configuration for
11232 elogind, and should be the result of an @code{(elogind-configuration
11233 (@var{parameter} @var{value})...)} invocation. Available parameters and
11234 their default values are:
11237 @item kill-user-processes?
11239 @item kill-only-users
11241 @item kill-exclude-users
11243 @item inhibit-delay-max-seconds
11245 @item handle-power-key
11247 @item handle-suspend-key
11249 @item handle-hibernate-key
11251 @item handle-lid-switch
11253 @item handle-lid-switch-docked
11255 @item power-key-ignore-inhibited?
11257 @item suspend-key-ignore-inhibited?
11259 @item hibernate-key-ignore-inhibited?
11261 @item lid-switch-ignore-inhibited?
11263 @item holdoff-timeout-seconds
11267 @item idle-action-seconds
11269 @item runtime-directory-size-percent
11271 @item runtime-directory-size
11275 @item suspend-state
11276 @code{("mem" "standby" "freeze")}
11279 @item hibernate-state
11281 @item hibernate-mode
11282 @code{("platform" "shutdown")}
11283 @item hybrid-sleep-state
11285 @item hybrid-sleep-mode
11286 @code{("suspend" "platform" "shutdown")}
11290 @deffn {Scheme Procedure} polkit-service @
11291 [#:polkit @var{polkit}]
11292 Return a service that runs the
11293 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11294 management service}, which allows system administrators to grant access to
11295 privileged operations in a structured way. By querying the Polkit service, a
11296 privileged system component can know when it should grant additional
11297 capabilities to ordinary users. For example, an ordinary user can be granted
11298 the capability to suspend the system if the user is logged in locally.
11301 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11302 [#:watts-up-pro? #f] @
11303 [#:poll-batteries? #t] @
11304 [#:ignore-lid? #f] @
11305 [#:use-percentage-for-policy? #f] @
11306 [#:percentage-low 10] @
11307 [#:percentage-critical 3] @
11308 [#:percentage-action 2] @
11309 [#:time-low 1200] @
11310 [#:time-critical 300] @
11311 [#:time-action 120] @
11312 [#:critical-power-action 'hybrid-sleep]
11313 Return a service that runs @uref{http://upower.freedesktop.org/,
11314 @command{upowerd}}, a system-wide monitor for power consumption and battery
11315 levels, with the given configuration settings. It implements the
11316 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11320 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11321 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11322 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11323 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11324 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11327 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11328 Return a service that runs @command{colord}, a system service with a D-Bus
11329 interface to manage the color profiles of input and output devices such as
11330 screens and scanners. It is notably used by the GNOME Color Manager graphical
11331 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11332 site} for more information.
11335 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11336 Return a configuration allowing an application to access GeoClue
11337 location data. @var{name} is the Desktop ID of the application, without
11338 the @code{.desktop} part. If @var{allowed?} is true, the application
11339 will have access to location information by default. The boolean
11340 @var{system?} value indicates whether an application is a system component
11341 or not. Finally @var{users} is a list of UIDs of all users for which
11342 this application is allowed location info access. An empty users list
11343 means that all users are allowed.
11346 @defvr {Scheme Variable} %standard-geoclue-applications
11347 The standard list of well-known GeoClue application configurations,
11348 granting authority to the GNOME date-and-time utility to ask for the
11349 current location in order to set the time zone, and allowing the
11350 IceCat and Epiphany web browsers to request location information.
11351 IceCat and Epiphany both query the user before allowing a web page to
11352 know the user's location.
11355 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11356 [#:whitelist '()] @
11357 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11358 [#:submit-data? #f]
11359 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11360 [#:submission-nick "geoclue"] @
11361 [#:applications %standard-geoclue-applications]
11362 Return a service that runs the GeoClue location service. This service
11363 provides a D-Bus interface to allow applications to request access to a
11364 user's physical location, and optionally to add information to online
11365 location databases. See
11366 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11367 web site} for more information.
11370 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11371 Return a service that runs the @command{bluetoothd} daemon, which manages
11372 all the Bluetooth devices and provides a number of D-Bus interfaces.
11374 Users need to be in the @code{lp} group to access the D-Bus service.
11377 @node Database Services
11378 @subsubsection Database Services
11382 The @code{(gnu services databases)} module provides the following services.
11384 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11385 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11386 [#:port 5432] [#:locale ``en_US.utf8'']
11387 Return a service that runs @var{postgresql}, the PostgreSQL database
11390 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11391 creates a database cluster with @var{locale} as the default
11392 locale, stored in @var{data-directory}. It then listens on @var{port}.
11395 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11396 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11399 The optional @var{config} argument specifies the configuration for
11400 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11403 @deftp {Data Type} mysql-configuration
11404 Data type representing the configuration of @var{mysql-service}.
11407 @item @code{mysql} (default: @var{mariadb})
11408 Package object of the MySQL database server, can be either @var{mariadb}
11411 For MySQL, a temporary root password will be displayed at activation time.
11412 For MariaDB, the root password is empty.
11414 @item @code{port} (default: @code{3306})
11415 TCP port on which the database server listens for incoming connections.
11419 @defvr {Scheme Variable} redis-service-type
11420 This is the service type for the @uref{https://redis.io/, Redis}
11421 key/value store, whose value is a @code{redis-configuration} object.
11424 @deftp {Data Type} redis-configuration
11425 Data type representing the configuration of redis.
11428 @item @code{redis} (default: @code{redis})
11429 The Redis package to use.
11431 @item @code{bind} (default: @code{"127.0.0.1"})
11432 Network interface on which to listen.
11434 @item @code{port} (default: @code{6379})
11435 Port on which to accept connections on, a value of 0 will disable
11436 listening on a TCP socket.
11438 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11439 Directory in which to store the database and related files.
11443 @node Mail Services
11444 @subsubsection Mail Services
11448 The @code{(gnu services mail)} module provides Guix service definitions
11449 for email services: IMAP, POP3, and LMTP servers, as well as mail
11450 transport agents (MTAs). Lots of acronyms! These services are detailed
11451 in the subsections below.
11453 @subsubheading Dovecot Service
11455 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11456 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11459 By default, Dovecot does not need much configuration; the default
11460 configuration object created by @code{(dovecot-configuration)} will
11461 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11462 certificate will be generated for TLS-protected connections, though
11463 Dovecot will also listen on cleartext ports by default. There are a
11464 number of options, though, which mail administrators might need to change,
11465 and as is the case with other services, Guix allows the system
11466 administrator to specify these parameters via a uniform Scheme interface.
11468 For example, to specify that mail is located at @code{maildir~/.mail},
11469 one would instantiate the Dovecot service like this:
11472 (dovecot-service #:config
11473 (dovecot-configuration
11474 (mail-location "maildir:~/.mail")))
11477 The available configuration parameters follow. Each parameter
11478 definition is preceded by its type; for example, @samp{string-list foo}
11479 indicates that the @code{foo} parameter should be specified as a list of
11480 strings. There is also a way to specify the configuration as a string,
11481 if you have an old @code{dovecot.conf} file that you want to port over
11482 from some other system; see the end for more details.
11484 @c The following documentation was initially generated by
11485 @c (generate-documentation) in (gnu services mail). Manually maintained
11486 @c documentation is better, so we shouldn't hesitate to edit below as
11487 @c needed. However if the change you want to make to this documentation
11488 @c can be done in an automated way, it's probably easier to change
11489 @c (generate-documentation) than to make it below and have to deal with
11490 @c the churn as dovecot updates.
11492 Available @code{dovecot-configuration} fields are:
11494 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11495 The dovecot package.
11498 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11499 A list of IPs or hosts where to listen for connections. @samp{*}
11500 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11501 interfaces. If you want to specify non-default ports or anything more
11502 complex, customize the address and port fields of the
11503 @samp{inet-listener} of the specific services you are interested in.
11506 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11507 List of protocols we want to serve. Available protocols include
11508 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11510 Available @code{protocol-configuration} fields are:
11512 @deftypevr {@code{protocol-configuration} parameter} string name
11513 The name of the protocol.
11516 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11517 UNIX socket path to the master authentication server to find users.
11518 This is used by imap (for shared users) and lda.
11519 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11522 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11523 Space separated list of plugins to load.
11526 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11527 Maximum number of IMAP connections allowed for a user from each IP
11528 address. NOTE: The username is compared case-sensitively.
11529 Defaults to @samp{10}.
11534 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11535 List of services to enable. Available services include @samp{imap},
11536 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11539 Available @code{service-configuration} fields are:
11541 @deftypevr {@code{service-configuration} parameter} string kind
11542 The service kind. Valid values include @code{director},
11543 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11544 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11545 @code{tcpwrap}, @code{quota-warning}, or anything else.
11548 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11549 Listeners for the service. A listener is either a
11550 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11551 an @code{inet-listener-configuration}.
11552 Defaults to @samp{()}.
11554 Available @code{unix-listener-configuration} fields are:
11556 @deftypevr {@code{unix-listener-configuration} parameter} string path
11557 Path to the file, relative to @code{base-dir} field. This is also used as
11561 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11562 The access mode for the socket.
11563 Defaults to @samp{"0600"}.
11566 @deftypevr {@code{unix-listener-configuration} parameter} string user
11567 The user to own the socket.
11568 Defaults to @samp{""}.
11571 @deftypevr {@code{unix-listener-configuration} parameter} string group
11572 The group to own the socket.
11573 Defaults to @samp{""}.
11577 Available @code{fifo-listener-configuration} fields are:
11579 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11580 Path to the file, relative to @code{base-dir} field. This is also used as
11584 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11585 The access mode for the socket.
11586 Defaults to @samp{"0600"}.
11589 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11590 The user to own the socket.
11591 Defaults to @samp{""}.
11594 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11595 The group to own the socket.
11596 Defaults to @samp{""}.
11600 Available @code{inet-listener-configuration} fields are:
11602 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11603 The protocol to listen for.
11606 @deftypevr {@code{inet-listener-configuration} parameter} string address
11607 The address on which to listen, or empty for all addresses.
11608 Defaults to @samp{""}.
11611 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11612 The port on which to listen.
11615 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11616 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11618 Defaults to @samp{#t}.
11623 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11624 Number of connections to handle before starting a new process.
11625 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11626 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11627 Defaults to @samp{1}.
11630 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11631 Number of processes to always keep waiting for more connections.
11632 Defaults to @samp{0}.
11635 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11636 If you set @samp{service-count 0}, you probably need to grow
11638 Defaults to @samp{256000000}.
11643 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11644 Dict configuration, as created by the @code{dict-configuration}
11647 Available @code{dict-configuration} fields are:
11649 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11650 A list of key-value pairs that this dict should hold.
11651 Defaults to @samp{()}.
11656 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11657 A list of passdb configurations, each one created by the
11658 @code{passdb-configuration} constructor.
11660 Available @code{passdb-configuration} fields are:
11662 @deftypevr {@code{passdb-configuration} parameter} string driver
11663 The driver that the passdb should use. Valid values include
11664 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11666 Defaults to @samp{"pam"}.
11669 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11670 Space separated list of arguments to the passdb driver.
11671 Defaults to @samp{""}.
11676 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11677 List of userdb configurations, each one created by the
11678 @code{userdb-configuration} constructor.
11680 Available @code{userdb-configuration} fields are:
11682 @deftypevr {@code{userdb-configuration} parameter} string driver
11683 The driver that the userdb should use. Valid values include
11684 @samp{passwd} and @samp{static}.
11685 Defaults to @samp{"passwd"}.
11688 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11689 Space separated list of arguments to the userdb driver.
11690 Defaults to @samp{""}.
11693 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11694 Override fields from passwd.
11695 Defaults to @samp{()}.
11700 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11701 Plug-in configuration, created by the @code{plugin-configuration}
11705 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11706 List of namespaces. Each item in the list is created by the
11707 @code{namespace-configuration} constructor.
11709 Available @code{namespace-configuration} fields are:
11711 @deftypevr {@code{namespace-configuration} parameter} string name
11712 Name for this namespace.
11715 @deftypevr {@code{namespace-configuration} parameter} string type
11716 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11717 Defaults to @samp{"private"}.
11720 @deftypevr {@code{namespace-configuration} parameter} string separator
11721 Hierarchy separator to use. You should use the same separator for
11722 all namespaces or some clients get confused. @samp{/} is usually a good
11723 one. The default however depends on the underlying mail storage
11725 Defaults to @samp{""}.
11728 @deftypevr {@code{namespace-configuration} parameter} string prefix
11729 Prefix required to access this namespace. This needs to be
11730 different for all namespaces. For example @samp{Public/}.
11731 Defaults to @samp{""}.
11734 @deftypevr {@code{namespace-configuration} parameter} string location
11735 Physical location of the mailbox. This is in the same format as
11736 mail_location, which is also the default for it.
11737 Defaults to @samp{""}.
11740 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11741 There can be only one INBOX, and this setting defines which
11743 Defaults to @samp{#f}.
11746 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11747 If namespace is hidden, it's not advertised to clients via NAMESPACE
11748 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11749 useful when converting from another server with different namespaces
11750 which you want to deprecate but still keep working. For example you can
11751 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11753 Defaults to @samp{#f}.
11756 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11757 Show the mailboxes under this namespace with the LIST command. This
11758 makes the namespace visible for clients that do not support the NAMESPACE
11759 extension. The special @code{children} value lists child mailboxes, but
11760 hides the namespace prefix.
11761 Defaults to @samp{#t}.
11764 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11765 Namespace handles its own subscriptions. If set to @code{#f}, the
11766 parent namespace handles them. The empty prefix should always have this
11768 Defaults to @samp{#t}.
11771 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11772 List of predefined mailboxes in this namespace.
11773 Defaults to @samp{()}.
11775 Available @code{mailbox-configuration} fields are:
11777 @deftypevr {@code{mailbox-configuration} parameter} string name
11778 Name for this mailbox.
11781 @deftypevr {@code{mailbox-configuration} parameter} string auto
11782 @samp{create} will automatically create this mailbox.
11783 @samp{subscribe} will both create and subscribe to the mailbox.
11784 Defaults to @samp{"no"}.
11787 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11788 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11789 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11790 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11791 Defaults to @samp{()}.
11798 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11799 Base directory where to store runtime data.
11800 Defaults to @samp{"/var/run/dovecot/"}.
11803 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11804 Greeting message for clients.
11805 Defaults to @samp{"Dovecot ready."}.
11808 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11809 List of trusted network ranges. Connections from these IPs are
11810 allowed to override their IP addresses and ports (for logging and for
11811 authentication checks). @samp{disable-plaintext-auth} is also ignored
11812 for these networks. Typically you would specify your IMAP proxy servers
11814 Defaults to @samp{()}.
11817 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11818 List of login access check sockets (e.g. tcpwrap).
11819 Defaults to @samp{()}.
11822 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11823 Show more verbose process titles (in ps). Currently shows user name
11824 and IP address. Useful for seeing who is actually using the IMAP
11825 processes (e.g. shared mailboxes or if the same uid is used for multiple
11827 Defaults to @samp{#f}.
11830 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11831 Should all processes be killed when Dovecot master process shuts down.
11832 Setting this to @code{#f} means that Dovecot can be upgraded without
11833 forcing existing client connections to close (although that could also
11834 be a problem if the upgrade is e.g. due to a security fix).
11835 Defaults to @samp{#t}.
11838 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11839 If non-zero, run mail commands via this many connections to doveadm
11840 server, instead of running them directly in the same process.
11841 Defaults to @samp{0}.
11844 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11845 UNIX socket or host:port used for connecting to doveadm server.
11846 Defaults to @samp{"doveadm-server"}.
11849 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11850 List of environment variables that are preserved on Dovecot startup
11851 and passed down to all of its child processes. You can also give
11852 key=value pairs to always set specific settings.
11855 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11856 Disable LOGIN command and all other plaintext authentications unless
11857 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11858 matches the local IP (i.e. you're connecting from the same computer),
11859 the connection is considered secure and plaintext authentication is
11860 allowed. See also ssl=required setting.
11861 Defaults to @samp{#t}.
11864 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11865 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11866 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11867 for caching to be used.
11868 Defaults to @samp{0}.
11871 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11872 Time to live for cached data. After TTL expires the cached record
11873 is no longer used, *except* if the main database lookup returns internal
11874 failure. We also try to handle password changes automatically: If
11875 user's previous authentication was successful, but this one wasn't, the
11876 cache isn't used. For now this works only with plaintext
11878 Defaults to @samp{"1 hour"}.
11881 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11882 TTL for negative hits (user not found, password mismatch).
11883 0 disables caching them completely.
11884 Defaults to @samp{"1 hour"}.
11887 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11888 List of realms for SASL authentication mechanisms that need them.
11889 You can leave it empty if you don't want to support multiple realms.
11890 Many clients simply use the first one listed here, so keep the default
11892 Defaults to @samp{()}.
11895 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11896 Default realm/domain to use if none was specified. This is used for
11897 both SASL realms and appending @@domain to username in plaintext
11899 Defaults to @samp{""}.
11902 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11903 List of allowed characters in username. If the user-given username
11904 contains a character not listed in here, the login automatically fails.
11905 This is just an extra check to make sure user can't exploit any
11906 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11907 you want to allow all characters, set this value to empty.
11908 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11911 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11912 Username character translations before it's looked up from
11913 databases. The value contains series of from -> to characters. For
11914 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11915 translated to @samp{@@}.
11916 Defaults to @samp{""}.
11919 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11920 Username formatting before it's looked up from databases. You can
11921 use the standard variables here, e.g. %Lu would lowercase the username,
11922 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11923 change the @samp{@@} into @samp{-AT-}. This translation is done after
11924 @samp{auth-username-translation} changes.
11925 Defaults to @samp{"%Lu"}.
11928 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11929 If you want to allow master users to log in by specifying the master
11930 username within the normal username string (i.e. not using SASL
11931 mechanism's support for it), you can specify the separator character
11932 here. The format is then <username><separator><master username>.
11933 UW-IMAP uses @samp{*} as the separator, so that could be a good
11935 Defaults to @samp{""}.
11938 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11939 Username to use for users logging in with ANONYMOUS SASL
11941 Defaults to @samp{"anonymous"}.
11944 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11945 Maximum number of dovecot-auth worker processes. They're used to
11946 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11947 They're automatically created and destroyed as needed.
11948 Defaults to @samp{30}.
11951 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11952 Host name to use in GSSAPI principal names. The default is to use
11953 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
11954 allow all keytab entries.
11955 Defaults to @samp{""}.
11958 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
11959 Kerberos keytab to use for the GSSAPI mechanism. Will use the
11960 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
11961 need to change the auth service to run as root to be able to read this
11963 Defaults to @samp{""}.
11966 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
11967 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
11968 and @samp{ntlm-auth} helper.
11969 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
11970 Defaults to @samp{#f}.
11973 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
11974 Path for Samba's @samp{ntlm-auth} helper binary.
11975 Defaults to @samp{"/usr/bin/ntlm_auth"}.
11978 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
11979 Time to delay before replying to failed authentications.
11980 Defaults to @samp{"2 secs"}.
11983 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
11984 Require a valid SSL client certificate or the authentication
11986 Defaults to @samp{#f}.
11989 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
11990 Take the username from client's SSL certificate, using
11991 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
11993 Defaults to @samp{#f}.
11996 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
11997 List of wanted authentication mechanisms. Supported mechanisms are:
11998 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
11999 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
12000 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
12001 @samp{disable-plaintext-auth} setting.
12004 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
12005 List of IPs or hostnames to all director servers, including ourself.
12006 Ports can be specified as ip:port. The default port is the same as what
12007 director service's @samp{inet-listener} is using.
12008 Defaults to @samp{()}.
12011 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
12012 List of IPs or hostnames to all backend mail servers. Ranges are
12013 allowed too, like 10.0.0.10-10.0.0.30.
12014 Defaults to @samp{()}.
12017 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
12018 How long to redirect users to a specific server after it no longer
12019 has any connections.
12020 Defaults to @samp{"15 min"}.
12023 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
12024 TCP/IP port that accepts doveadm connections (instead of director
12025 connections) If you enable this, you'll also need to add
12026 @samp{inet-listener} for the port.
12027 Defaults to @samp{0}.
12030 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
12031 How the username is translated before being hashed. Useful values
12032 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
12033 are shared within domain.
12034 Defaults to @samp{"%Lu"}.
12037 @deftypevr {@code{dovecot-configuration} parameter} string log-path
12038 Log file to use for error messages. @samp{syslog} logs to syslog,
12039 @samp{/dev/stderr} logs to stderr.
12040 Defaults to @samp{"syslog"}.
12043 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
12044 Log file to use for informational messages. Defaults to
12046 Defaults to @samp{""}.
12049 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
12050 Log file to use for debug messages. Defaults to
12051 @samp{info-log-path}.
12052 Defaults to @samp{""}.
12055 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
12056 Syslog facility to use if you're logging to syslog. Usually if you
12057 don't want to use @samp{mail}, you'll use local0..local7. Also other
12058 standard facilities are supported.
12059 Defaults to @samp{"mail"}.
12062 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
12063 Log unsuccessful authentication attempts and the reasons why they
12065 Defaults to @samp{#f}.
12068 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
12069 In case of password mismatches, log the attempted password. Valid
12070 values are no, plain and sha1. sha1 can be useful for detecting brute
12071 force password attempts vs. user simply trying the same password over
12072 and over again. You can also truncate the value to n chars by appending
12073 ":n" (e.g. sha1:6).
12074 Defaults to @samp{#f}.
12077 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
12078 Even more verbose logging for debugging purposes. Shows for example
12080 Defaults to @samp{#f}.
12083 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
12084 In case of password mismatches, log the passwords and used scheme so
12085 the problem can be debugged. Enabling this also enables
12087 Defaults to @samp{#f}.
12090 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
12091 Enable mail process debugging. This can help you figure out why
12092 Dovecot isn't finding your mails.
12093 Defaults to @samp{#f}.
12096 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
12097 Show protocol level SSL errors.
12098 Defaults to @samp{#f}.
12101 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
12102 Prefix for each line written to log file. % codes are in
12103 strftime(3) format.
12104 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
12107 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
12108 List of elements we want to log. The elements which have a
12109 non-empty variable value are joined together to form a comma-separated
12113 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
12114 Login log format. %s contains @samp{login-log-format-elements}
12115 string, %$ contains the data we want to log.
12116 Defaults to @samp{"%$: %s"}.
12119 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
12120 Log prefix for mail processes. See doc/wiki/Variables.txt for list
12121 of possible variables you can use.
12122 Defaults to @samp{"\"%s(%u): \""}.
12125 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
12126 Format to use for logging mail deliveries. You can use variables:
12129 Delivery status message (e.g. @samp{saved to INBOX})
12141 Defaults to @samp{"msgid=%m: %$"}.
12144 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12145 Location for users' mailboxes. The default is empty, which means
12146 that Dovecot tries to find the mailboxes automatically. This won't work
12147 if the user doesn't yet have any mail, so you should explicitly tell
12148 Dovecot the full location.
12150 If you're using mbox, giving a path to the INBOX
12151 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12152 where the other mailboxes are kept. This is called the "root mail
12153 directory", and it must be the first path given in the
12154 @samp{mail-location} setting.
12156 There are a few special variables you can use, eg.:
12162 user part in user@@domain, same as %u if there's no domain
12164 domain part in user@@domain, empty if there's no domain
12169 See doc/wiki/Variables.txt for full list. Some examples:
12171 @item maildir:~/Maildir
12172 @item mbox:~/mail:INBOX=/var/mail/%u
12173 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12175 Defaults to @samp{""}.
12178 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12179 System user and group used to access mails. If you use multiple,
12180 userdb can override these by returning uid or gid fields. You can use
12181 either numbers or names. <doc/wiki/UserIds.txt>.
12182 Defaults to @samp{""}.
12185 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12187 Defaults to @samp{""}.
12190 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12191 Group to enable temporarily for privileged operations. Currently
12192 this is used only with INBOX when either its initial creation or
12193 dotlocking fails. Typically this is set to "mail" to give access to
12195 Defaults to @samp{""}.
12198 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12199 Grant access to these supplementary groups for mail processes.
12200 Typically these are used to set up access to shared mailboxes. Note
12201 that it may be dangerous to set these if users can create
12202 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12203 could allow a user to delete others' mailboxes, or ln -s
12204 /secret/shared/box ~/mail/mybox would allow reading it).
12205 Defaults to @samp{""}.
12208 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12209 Allow full file system access to clients. There's no access checks
12210 other than what the operating system does for the active UID/GID. It
12211 works with both maildir and mboxes, allowing you to prefix mailboxes
12212 names with e.g. /path/ or ~user/.
12213 Defaults to @samp{#f}.
12216 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12217 Don't use mmap() at all. This is required if you store indexes to
12218 shared file systems (NFS or clustered file system).
12219 Defaults to @samp{#f}.
12222 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12223 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12224 supports @samp{O_EXCL} since version 3, so this should be safe to use
12225 nowadays by default.
12226 Defaults to @samp{#t}.
12229 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12230 When to use fsync() or fdatasync() calls:
12233 Whenever necessary to avoid losing important data
12235 Useful with e.g. NFS when write()s are delayed
12237 Never use it (best performance, but crashes can lose data).
12239 Defaults to @samp{"optimized"}.
12242 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12243 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12244 NFS caches whenever needed. If you're using only a single mail server
12246 Defaults to @samp{#f}.
12249 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12250 Mail index files also exist in NFS. Setting this to yes requires
12251 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12252 Defaults to @samp{#f}.
12255 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12256 Locking method for index files. Alternatives are fcntl, flock and
12257 dotlock. Dotlocking uses some tricks which may create more disk I/O
12258 than other locking methods. NFS users: flock doesn't work, remember to
12259 change @samp{mmap-disable}.
12260 Defaults to @samp{"fcntl"}.
12263 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12264 Directory in which LDA/LMTP temporarily stores incoming mails >128
12266 Defaults to @samp{"/tmp"}.
12269 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12270 Valid UID range for users. This is mostly to make sure that users can't
12271 log in as daemons or other system users. Note that denying root logins is
12272 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12274 Defaults to @samp{500}.
12277 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12279 Defaults to @samp{0}.
12282 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12283 Valid GID range for users. Users having non-valid GID as primary group ID
12284 aren't allowed to log in. If user belongs to supplementary groups with
12285 non-valid GIDs, those groups are not set.
12286 Defaults to @samp{1}.
12289 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12291 Defaults to @samp{0}.
12294 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12295 Maximum allowed length for mail keyword name. It's only forced when
12296 trying to create new keywords.
12297 Defaults to @samp{50}.
12300 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12301 List of directories under which chrooting is allowed for mail
12302 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12303 too). This setting doesn't affect @samp{login-chroot}
12304 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12305 "/./" in home dirs are ignored. WARNING: Never add directories here
12306 which local users can modify, that may lead to root exploit. Usually
12307 this should be done only if you don't allow shell access for users.
12308 <doc/wiki/Chrooting.txt>.
12309 Defaults to @samp{()}.
12312 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12313 Default chroot directory for mail processes. This can be overridden
12314 for specific users in user database by giving /./ in user's home
12315 directory (e.g. /home/./user chroots into /home). Note that usually
12316 there is no real need to do chrooting, Dovecot doesn't allow users to
12317 access files outside their mail directory anyway. If your home
12318 directories are prefixed with the chroot directory, append "/." to
12319 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12320 Defaults to @samp{""}.
12323 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12324 UNIX socket path to master authentication server to find users.
12325 This is used by imap (for shared users) and lda.
12326 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12329 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12330 Directory where to look up mail plugins.
12331 Defaults to @samp{"/usr/lib/dovecot"}.
12334 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12335 List of plugins to load for all services. Plugins specific to IMAP,
12336 LDA, etc. are added to this list in their own .conf files.
12337 Defaults to @samp{()}.
12340 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12341 The minimum number of mails in a mailbox before updates are done to
12342 cache file. This allows optimizing Dovecot's behavior to do less disk
12343 writes at the cost of more disk reads.
12344 Defaults to @samp{0}.
12347 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12348 When IDLE command is running, mailbox is checked once in a while to
12349 see if there are any new mails or other changes. This setting defines
12350 the minimum time to wait between those checks. Dovecot can also use
12351 dnotify, inotify and kqueue to find out immediately when changes
12353 Defaults to @samp{"30 secs"}.
12356 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12357 Save mails with CR+LF instead of plain LF. This makes sending those
12358 mails take less CPU, especially with sendfile() syscall with Linux and
12359 FreeBSD. But it also creates a bit more disk I/O which may just make it
12360 slower. Also note that if other software reads the mboxes/maildirs,
12361 they may handle the extra CRs wrong and cause problems.
12362 Defaults to @samp{#f}.
12365 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12366 By default LIST command returns all entries in maildir beginning
12367 with a dot. Enabling this option makes Dovecot return only entries
12368 which are directories. This is done by stat()ing each entry, so it
12369 causes more disk I/O.
12370 (For systems setting struct @samp{dirent->d_type} this check is free
12371 and it's done always regardless of this setting).
12372 Defaults to @samp{#f}.
12375 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12376 When copying a message, do it with hard links whenever possible.
12377 This makes the performance much better, and it's unlikely to have any
12379 Defaults to @samp{#t}.
12382 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12383 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12384 directory only when its mtime changes unexpectedly or when we can't find
12385 the mail otherwise.
12386 Defaults to @samp{#f}.
12389 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12390 Which locking methods to use for locking mbox. There are four
12395 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12396 solution. If you want to use /var/mail/ like directory, the users will
12397 need write access to that directory.
12399 Same as dotlock, but if it fails because of permissions or because there
12400 isn't enough disk space, just skip it.
12402 Use this if possible. Works with NFS too if lockd is used.
12404 May not exist in all systems. Doesn't work with NFS.
12406 May not exist in all systems. Doesn't work with NFS.
12409 You can use multiple locking methods; if you do the order they're declared
12410 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12411 locking methods as well. Some operating systems don't allow using some of
12412 them simultaneously.
12415 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12419 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12420 Maximum time to wait for lock (all of them) before aborting.
12421 Defaults to @samp{"5 mins"}.
12424 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12425 If dotlock exists but the mailbox isn't modified in any way,
12426 override the lock file after this much time.
12427 Defaults to @samp{"2 mins"}.
12430 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12431 When mbox changes unexpectedly we have to fully read it to find out
12432 what changed. If the mbox is large this can take a long time. Since
12433 the change is usually just a newly appended mail, it'd be faster to
12434 simply read the new mails. If this setting is enabled, Dovecot does
12435 this but still safely fallbacks to re-reading the whole mbox file
12436 whenever something in mbox isn't how it's expected to be. The only real
12437 downside to this setting is that if some other MUA changes message
12438 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12439 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12440 Defaults to @samp{#t}.
12443 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12444 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12445 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12446 @samp{mbox-dirty-syncs} is ignored.
12447 Defaults to @samp{#f}.
12450 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12451 Delay writing mbox headers until doing a full write sync (EXPUNGE
12452 and CHECK commands and when closing the mailbox). This is especially
12453 useful for POP3 where clients often delete all mails. The downside is
12454 that our changes aren't immediately visible to other MUAs.
12455 Defaults to @samp{#t}.
12458 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12459 If mbox size is smaller than this (e.g. 100k), don't write index
12460 files. If an index file already exists it's still read, just not
12462 Defaults to @samp{0}.
12465 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12466 Maximum dbox file size until it's rotated.
12467 Defaults to @samp{2000000}.
12470 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12471 Maximum dbox file age until it's rotated. Typically in days. Day
12472 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12474 Defaults to @samp{"1d"}.
12477 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12478 When creating new mdbox files, immediately preallocate their size to
12479 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12480 with some file systems (ext4, xfs).
12481 Defaults to @samp{#f}.
12484 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12485 sdbox and mdbox support saving mail attachments to external files,
12486 which also allows single instance storage for them. Other backends
12487 don't support this for now.
12489 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12491 Directory root where to store mail attachments. Disabled, if empty.
12492 Defaults to @samp{""}.
12495 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12496 Attachments smaller than this aren't saved externally. It's also
12497 possible to write a plugin to disable saving specific attachments
12499 Defaults to @samp{128000}.
12502 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12503 File system backend to use for saving attachments:
12506 No SiS done by Dovecot (but this might help FS's own deduplication)
12508 SiS with immediate byte-by-byte comparison during saving
12509 @item sis-queue posix
12510 SiS with delayed comparison and deduplication.
12512 Defaults to @samp{"sis posix"}.
12515 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12516 Hash format to use in attachment filenames. You can add any text and
12517 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12518 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12519 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12520 Defaults to @samp{"%@{sha1@}"}.
12523 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12525 Defaults to @samp{100}.
12528 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12530 Defaults to @samp{1000}.
12533 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12534 Default VSZ (virtual memory size) limit for service processes.
12535 This is mainly intended to catch and kill processes that leak memory
12536 before they eat up everything.
12537 Defaults to @samp{256000000}.
12540 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12541 Login user is internally used by login processes. This is the most
12542 untrusted user in Dovecot system. It shouldn't have access to anything
12544 Defaults to @samp{"dovenull"}.
12547 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12548 Internal user is used by unprivileged processes. It should be
12549 separate from login user, so that login processes can't disturb other
12551 Defaults to @samp{"dovecot"}.
12554 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12555 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12556 Defaults to @samp{"required"}.
12559 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12560 PEM encoded X.509 SSL/TLS certificate (public key).
12561 Defaults to @samp{"</etc/dovecot/default.pem"}.
12564 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12565 PEM encoded SSL/TLS private key. The key is opened before
12566 dropping root privileges, so keep the key file unreadable by anyone but
12568 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12571 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12572 If key file is password protected, give the password here.
12573 Alternatively give it when starting dovecot with -p parameter. Since
12574 this file is often world-readable, you may want to place this setting
12575 instead to a different.
12576 Defaults to @samp{""}.
12579 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12580 PEM encoded trusted certificate authority. Set this only if you
12581 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12582 contain the CA certificate(s) followed by the matching
12583 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12584 Defaults to @samp{""}.
12587 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12588 Require that CRL check succeeds for client certificates.
12589 Defaults to @samp{#t}.
12592 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12593 Request client to send a certificate. If you also want to require
12594 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12595 Defaults to @samp{#f}.
12598 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12599 Which field from certificate to use for username. commonName and
12600 x500UniqueIdentifier are the usual choices. You'll also need to set
12601 @samp{auth-ssl-username-from-cert? #t}.
12602 Defaults to @samp{"commonName"}.
12605 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12606 How often to regenerate the SSL parameters file. Generation is
12607 quite CPU intensive operation. The value is in hours, 0 disables
12608 regeneration entirely.
12609 Defaults to @samp{168}.
12612 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12613 SSL protocols to use.
12614 Defaults to @samp{"!SSLv2"}.
12617 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12618 SSL ciphers to use.
12619 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12622 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12623 SSL crypto device to use, for valid values run "openssl engine".
12624 Defaults to @samp{""}.
12627 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12628 Address to use when sending rejection mails.
12629 %d expands to recipient domain.
12630 Defaults to @samp{"postmaster@@%d"}.
12633 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12634 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12635 and in LMTP replies. Default is the system's real hostname@@domain.
12636 Defaults to @samp{""}.
12639 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12640 If user is over quota, return with temporary failure instead of
12642 Defaults to @samp{#f}.
12645 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12646 Binary to use for sending mails.
12647 Defaults to @samp{"/usr/sbin/sendmail"}.
12650 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12651 If non-empty, send mails via this SMTP host[:port] instead of
12653 Defaults to @samp{""}.
12656 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12657 Subject: header to use for rejection mails. You can use the same
12658 variables as for @samp{rejection-reason} below.
12659 Defaults to @samp{"Rejected: %s"}.
12662 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12663 Human readable error message for rejection mails. You can use
12676 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12679 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12680 Delimiter character between local-part and detail in email
12682 Defaults to @samp{"+"}.
12685 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12686 Header where the original recipient address (SMTP's RCPT TO:
12687 address) is taken from if not available elsewhere. With dovecot-lda -a
12688 parameter overrides this. A commonly used header for this is
12690 Defaults to @samp{""}.
12693 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12694 Should saving a mail to a nonexistent mailbox automatically create
12696 Defaults to @samp{#f}.
12699 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12700 Should automatically created mailboxes be also automatically
12702 Defaults to @samp{#f}.
12705 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12706 Maximum IMAP command line length. Some clients generate very long
12707 command lines with huge mailboxes, so you may need to raise this if you
12708 get "Too long argument" or "IMAP command line too large" errors
12710 Defaults to @samp{64000}.
12713 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12714 IMAP logout format string:
12717 total number of bytes read from client
12719 total number of bytes sent to client.
12721 Defaults to @samp{"in=%i out=%o"}.
12724 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12725 Override the IMAP CAPABILITY response. If the value begins with '+',
12726 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12727 Defaults to @samp{""}.
12730 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12731 How long to wait between "OK Still here" notifications when client
12733 Defaults to @samp{"2 mins"}.
12736 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12737 ID field names and values to send to clients. Using * as the value
12738 makes Dovecot use the default value. The following fields have default
12739 values currently: name, version, os, os-version, support-url,
12741 Defaults to @samp{""}.
12744 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12745 ID fields sent by client to log. * means everything.
12746 Defaults to @samp{""}.
12749 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12750 Workarounds for various client bugs:
12753 @item delay-newmail
12754 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12755 CHECK commands. Some clients ignore them otherwise, for example OSX
12756 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12757 may show user "Message no longer in server" errors. Note that OE6
12758 still breaks even with this workaround if synchronization is set to
12761 @item tb-extra-mailbox-sep
12762 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12763 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12764 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12766 @item tb-lsub-flags
12767 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12768 This makes Thunderbird realize they aren't selectable and show them
12769 greyed out, instead of only later giving "not selectable" popup error.
12771 Defaults to @samp{()}.
12774 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12775 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12776 Defaults to @samp{""}.
12780 Whew! Lots of configuration options. The nice thing about it though is
12781 that GuixSD has a complete interface to Dovecot's configuration
12782 language. This allows not only a nice way to declare configurations,
12783 but also offers reflective capabilities as well: users can write code to
12784 inspect and transform configurations from within Scheme.
12786 However, it could be that you just want to get a @code{dovecot.conf} up
12787 and running. In that case, you can pass an
12788 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12789 @code{dovecot-service}. As its name indicates, an opaque configuration
12790 does not have easy reflective capabilities.
12792 Available @code{opaque-dovecot-configuration} fields are:
12794 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12795 The dovecot package.
12798 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12799 The contents of the @code{dovecot.conf}, as a string.
12802 For example, if your @code{dovecot.conf} is just the empty string, you
12803 could instantiate a dovecot service like this:
12806 (dovecot-service #:config
12807 (opaque-dovecot-configuration
12811 @subsubheading OpenSMTPD Service
12813 @deffn {Scheme Variable} opensmtpd-service-type
12814 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12815 service, whose value should be an @code{opensmtpd-configuration} object
12816 as in this example:
12819 (service opensmtpd-service-type
12820 (opensmtpd-configuration
12821 (config-file (local-file "./my-smtpd.conf"))))
12825 @deftp {Data Type} opensmtpd-configuration
12826 Data type representing the configuration of opensmtpd.
12829 @item @code{package} (default: @var{opensmtpd})
12830 Package object of the OpenSMTPD SMTP server.
12832 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12833 File-like object of the OpenSMTPD configuration file to use. By default
12834 it listens on the loopback network interface, and allows for mail from
12835 users and daemons on the local machine, as well as permitting email to
12836 remote servers. Run @command{man smtpd.conf} for more information.
12841 @subsubheading Exim Service
12843 @cindex mail transfer agent (MTA)
12844 @cindex MTA (mail transfer agent)
12847 @deffn {Scheme Variable} exim-service-type
12848 This is the type of the @uref{https://exim.org, Exim} mail transfer
12849 agent (MTA), whose value should be an @code{exim-configuration} object
12850 as in this example:
12853 (service exim-service-type
12854 (exim-configuration
12855 (config-file (local-file "./my-exim.conf"))))
12859 In order to use an @code{exim-service-type} service you must also have a
12860 @code{mail-aliases-service-type} service present in your
12861 @code{operating-system} (even if it has no aliases).
12863 @deftp {Data Type} exim-configuration
12864 Data type representing the configuration of exim.
12867 @item @code{package} (default: @var{exim})
12868 Package object of the Exim server.
12870 @item @code{config-file} (default: @code{#f})
12871 File-like object of the Exim configuration file to use. If its value is
12872 @code{#f} then use the default configuration file from the package
12873 provided in @code{package}. The resulting configuration file is loaded
12874 after setting the @code{exim_user} and @code{exim_group} configuration
12880 @subsubheading Mail Aliases Service
12882 @cindex email aliases
12883 @cindex aliases, for email addresses
12885 @deffn {Scheme Variable} mail-aliases-service-type
12886 This is the type of the service which provides @code{/etc/aliases},
12887 specifying how to deliver mail to users on this system.
12890 (service mail-aliases-service-type
12891 '(("postmaster" "bob")
12892 ("bob" "bob@@example.com" "bob@@example2.com")))
12896 The configuration for a @code{mail-aliases-service-type} service is an
12897 association list denoting how to deliver mail that comes to this
12898 system. Each entry is of the form @code{(alias addresses ...)}, with
12899 @code{alias} specifying the local alias and @code{addresses} specifying
12900 where to deliver this user's mail.
12902 The aliases aren't required to exist as users on the local system. In
12903 the above example, there doesn't need to be a @code{postmaster} entry in
12904 the @code{operating-system}'s @code{user-accounts} in order to deliver
12905 the @code{postmaster} mail to @code{bob} (which subsequently would
12906 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
12908 @node Messaging Services
12909 @subsubsection Messaging Services
12914 The @code{(gnu services messaging)} module provides Guix service
12915 definitions for messaging services: currently only Prosody is supported.
12917 @subsubheading Prosody Service
12919 @deffn {Scheme Variable} prosody-service-type
12920 This is the type for the @uref{http://prosody.im, Prosody XMPP
12921 communication server}. Its value must be a @code{prosody-configuration}
12922 record as in this example:
12925 (service prosody-service-type
12926 (prosody-configuration
12927 (modules-enabled (cons "groups" %default-modules-enabled))
12930 (int-component-configuration
12931 (hostname "conference.example.net")
12933 (mod-muc (mod-muc-configuration)))))
12936 (virtualhost-configuration
12937 (domain "example.net"))))))
12940 See below for details about @code{prosody-configuration}.
12944 By default, Prosody does not need much configuration. Only one
12945 @code{virtualhosts} field is needed: it specifies the domain you wish
12948 Prosodyctl will help you generate X.509 certificates and keys:
12951 prosodyctl cert request example.net
12954 The available configuration parameters follow. Each parameter
12955 definition is preceded by its type; for example, @samp{string-list foo}
12956 indicates that the @code{foo} parameter should be specified as a list of
12957 strings. Types starting with @code{maybe-} denote parameters that won't
12958 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
12960 There is also a way to specify the configuration as a string, if you
12961 have an old @code{prosody.cfg.lua} file that you want to port over from
12962 some other system; see the end for more details.
12964 @c The following documentation was initially generated by
12965 @c (generate-documentation) in (gnu services messaging). Manually maintained
12966 @c documentation is better, so we shouldn't hesitate to edit below as
12967 @c needed. However if the change you want to make to this documentation
12968 @c can be done in an automated way, it's probably easier to change
12969 @c (generate-documentation) than to make it below and have to deal with
12970 @c the churn as Prosody updates.
12972 Available @code{prosody-configuration} fields are:
12974 @deftypevr {@code{prosody-configuration} parameter} package prosody
12975 The Prosody package.
12978 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
12979 Location of the Prosody data storage directory. See
12980 @url{http://prosody.im/doc/configure}.
12981 Defaults to @samp{"/var/lib/prosody"}.
12984 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
12985 Additional plugin directories. They are searched in all the specified
12986 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
12987 Defaults to @samp{()}.
12990 @deftypevr {@code{prosody-configuration} parameter} string-list admins
12991 This is a list of accounts that are admins for the server. Note that you
12992 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
12993 @url{http://prosody.im/doc/creating_accounts}.
12994 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
12995 Defaults to @samp{()}.
12998 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
12999 Enable use of libevent for better performance under high load. See
13000 @url{http://prosody.im/doc/libevent}.
13001 Defaults to @samp{#f}.
13004 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
13005 This is the list of modules Prosody will load on startup. It looks for
13006 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
13007 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
13008 Defaults to @samp{%default-modules-enabled}.
13011 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
13012 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
13013 should you want to disable them then add them to this list.
13014 Defaults to @samp{()}.
13017 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
13018 Path to a text file where the shared groups are defined. If this path is
13019 empty then @samp{mod_groups} does nothing. See
13020 @url{http://prosody.im/doc/modules/mod_groups}.
13021 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
13024 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
13025 Disable account creation by default, for security. See
13026 @url{http://prosody.im/doc/creating_accounts}.
13027 Defaults to @samp{#f}.
13030 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
13031 These are the SSL/TLS-related settings. Most of them are disabled so to
13032 use Prosody's defaults. If you do not completely understand these options, do
13033 not add them to your config, it is easy to lower the security of your server
13034 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
13036 Available @code{ssl-configuration} fields are:
13038 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
13039 This determines what handshake to use.
13042 @deftypevr {@code{ssl-configuration} parameter} file-name key
13043 Path to your private key file, relative to @code{/etc/prosody}.
13044 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
13047 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
13048 Path to your certificate file, relative to @code{/etc/prosody}.
13049 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
13052 @deftypevr {@code{ssl-configuration} parameter} file-name capath
13053 Path to directory containing root certificates that you wish Prosody to
13054 trust when verifying the certificates of remote servers.
13055 Defaults to @samp{"/etc/ssl/certs"}.
13058 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
13059 Path to a file containing root certificates that you wish Prosody to trust.
13060 Similar to @code{capath} but with all certificates concatenated together.
13063 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
13064 A list of verification options (these mostly map to OpenSSL's
13065 @code{set_verify()} flags).
13068 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
13069 A list of general options relating to SSL/TLS. These map to OpenSSL's
13070 @code{set_options()}. For a full list of options available in LuaSec, see the
13074 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
13075 How long a chain of certificate authorities to check when looking for a
13076 trusted root certificate.
13079 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
13080 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
13081 clients, and in what order.
13084 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
13085 A path to a file containing parameters for Diffie-Hellman key exchange. You
13086 can create such a file with:
13087 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
13090 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
13091 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
13092 @samp{"secp384r1"}.
13095 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
13096 A list of "extra" verification options.
13099 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
13100 Password for encrypted private keys.
13105 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
13106 Whether to force all client-to-server connections to be encrypted or not.
13107 See @url{http://prosody.im/doc/modules/mod_tls}.
13108 Defaults to @samp{#f}.
13111 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
13112 Whether to force all server-to-server connections to be encrypted or not.
13113 See @url{http://prosody.im/doc/modules/mod_tls}.
13114 Defaults to @samp{#f}.
13117 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
13118 Whether to require encryption and certificate authentication. This
13119 provides ideal security, but requires servers you communicate with to support
13120 encryption AND present valid, trusted certificates. See
13121 @url{http://prosody.im/doc/s2s#security}.
13122 Defaults to @samp{#f}.
13125 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
13126 Many servers don't support encryption or have invalid or self-signed
13127 certificates. You can list domains here that will not be required to
13128 authenticate using certificates. They will be authenticated using DNS. See
13129 @url{http://prosody.im/doc/s2s#security}.
13130 Defaults to @samp{()}.
13133 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13134 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13135 valid certificates for some domains by specifying a list here. See
13136 @url{http://prosody.im/doc/s2s#security}.
13137 Defaults to @samp{()}.
13140 @deftypevr {@code{prosody-configuration} parameter} string authentication
13141 Select the authentication backend to use. The default provider stores
13142 passwords in plaintext and uses Prosody's configured data storage to store the
13143 authentication data. If you do not trust your server please see
13144 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13145 about using the hashed backend. See also
13146 @url{http://prosody.im/doc/authentication}
13147 Defaults to @samp{"internal_plain"}.
13150 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13151 Set logging options. Advanced logging configuration is not yet supported
13152 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13153 Defaults to @samp{"*syslog"}.
13156 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13157 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13158 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13161 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13162 A host in Prosody is a domain on which user accounts can be created. For
13163 example if you want your users to have addresses like
13164 @samp{"john.smith@@example.com"} then you need to add a host
13165 @samp{"example.com"}. All options in this list will apply only to this host.
13167 Note: the name "virtual" host is used in configuration to avoid confusion with
13168 the actual physical host that Prosody is installed on. A single Prosody
13169 instance can serve many domains, each one defined as a VirtualHost entry in
13170 Prosody's configuration. Conversely a server that hosts a single domain would
13171 have just one VirtualHost entry.
13173 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13175 Available @code{virtualhost-configuration} fields are:
13177 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:
13178 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13179 Domain you wish Prosody to serve.
13184 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13185 Components are extra services on a server which are available to clients,
13186 usually on a subdomain of the main server (such as
13187 @samp{"mycomponent.example.com"}). Example components might be chatroom
13188 servers, user directories, or gateways to other protocols.
13190 Internal components are implemented with Prosody-specific plugins. To add an
13191 internal component, you simply fill the hostname field, and the plugin you wish
13192 to use for the component.
13194 See @url{http://prosody.im/doc/components}.
13195 Defaults to @samp{()}.
13197 Available @code{int-component-configuration} fields are:
13199 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:
13200 @deftypevr {@code{int-component-configuration} parameter} string hostname
13201 Hostname of the component.
13204 @deftypevr {@code{int-component-configuration} parameter} string plugin
13205 Plugin you wish to use for the component.
13208 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13209 Multi-user chat (MUC) is Prosody's module for allowing you to create
13210 hosted chatrooms/conferences for XMPP users.
13212 General information on setting up and using multi-user chatrooms can be found
13213 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13214 which you should read if you are new to XMPP chatrooms.
13216 See also @url{http://prosody.im/doc/modules/mod_muc}.
13218 Available @code{mod-muc-configuration} fields are:
13220 @deftypevr {@code{mod-muc-configuration} parameter} string name
13221 The name to return in service discovery responses.
13222 Defaults to @samp{"Prosody Chatrooms"}.
13225 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13226 If @samp{#t}, this will only allow admins to create new chatrooms.
13227 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13228 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13229 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13230 restricts to service administrators only.
13231 Defaults to @samp{#f}.
13234 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13235 Maximum number of history messages that will be sent to the member that has
13236 just joined the room.
13237 Defaults to @samp{20}.
13244 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13245 External components use XEP-0114, which most standalone components
13246 support. To add an external component, you simply fill the hostname field. See
13247 @url{http://prosody.im/doc/components}.
13248 Defaults to @samp{()}.
13250 Available @code{ext-component-configuration} fields are:
13252 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:
13253 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13254 Password which the component will use to log in.
13257 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13258 Hostname of the component.
13263 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13264 Port(s) Prosody listens on for component connections.
13267 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13268 Interface Prosody listens on for component connections.
13269 Defaults to @samp{"127.0.0.1"}.
13272 It could be that you just want to get a @code{prosody.cfg.lua}
13273 up and running. In that case, you can pass an
13274 @code{opaque-prosody-configuration} record as the value of
13275 @code{prosody-service-type}. As its name indicates, an opaque configuration
13276 does not have easy reflective capabilities.
13277 Available @code{opaque-prosody-configuration} fields are:
13279 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13280 The prosody package.
13283 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13284 The contents of the @code{prosody.cfg.lua} to use.
13287 For example, if your @code{prosody.cfg.lua} is just the empty
13288 string, you could instantiate a prosody service like this:
13291 (service prosody-service-type
13292 (opaque-prosody-configuration
13293 (prosody.cfg.lua "")))
13296 @node Kerberos Services
13297 @subsubsection Kerberos Services
13300 The @code{(gnu services kerberos)} module provides services relating to
13301 the authentication protocol @dfn{Kerberos}.
13303 @subsubheading Krb5 Service
13305 Programs using a Kerberos client library normally
13306 expect a configuration file in @file{/etc/krb5.conf}.
13307 This service generates such a file from a definition provided in the
13308 operating system declaration.
13309 It does not cause any daemon to be started.
13311 No ``keytab'' files are provided by this service---you must explicitly create them.
13312 This service is known to work with the MIT client library, @code{mit-krb5}.
13313 Other implementations have not been tested.
13315 @defvr {Scheme Variable} krb5-service-type
13316 A service type for Kerberos 5 clients.
13320 Here is an example of its use:
13322 (service krb5-service-type
13323 (krb5-configuration
13324 (default-realm "EXAMPLE.COM")
13325 (allow-weak-crypto? #t)
13328 (name "EXAMPLE.COM")
13329 (admin-server "groucho.example.com")
13330 (kdc "karl.example.com"))
13333 (admin-server "kerb-admin.argrx.edu")
13334 (kdc "keys.argrx.edu"))))))
13338 This example provides a Kerberos@tie{}5 client configuration which:
13340 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13341 of which have distinct administration servers and key distribution centers;
13342 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13343 specified by clients;
13344 @item Accepts services which only support encryption types known to be weak.
13347 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13348 Only the most commonly used ones are described here.
13349 For a full list, and more detailed explanation of each, see the MIT
13350 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13354 @deftp {Data Type} krb5-realm
13355 @cindex realm, kerberos
13358 This field is a string identifying the name of the realm.
13359 A common convention is to use the fully qualified DNS name of your organization,
13360 converted to upper case.
13362 @item @code{admin-server}
13363 This field is a string identifying the host where the administration server is
13367 This field is a string identifying the key distribution center
13372 @deftp {Data Type} krb5-configuration
13375 @item @code{allow-weak-crypto?} (default: @code{#f})
13376 If this flag is @code{#t} then services which only offer encryption algorithms
13377 known to be weak will be accepted.
13379 @item @code{default-realm} (default: @code{#f})
13380 This field should be a string identifying the default Kerberos
13381 realm for the client.
13382 You should set this field to the name of your Kerberos realm.
13383 If this value is @code{#f}
13384 then a realm must be specified with every Kerberos principal when invoking programs
13385 such as @command{kinit}.
13387 @item @code{realms}
13388 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13390 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13396 @subsubheading PAM krb5 Service
13399 The @code{pam-krb5} service allows for login authentication and password
13400 management via Kerberos.
13401 You will need this service if you want PAM enabled applications to authenticate
13402 users using Kerberos.
13404 @defvr {Scheme Variable} pam-krb5-service-type
13405 A service type for the Kerberos 5 PAM module.
13408 @deftp {Data Type} pam-krb5-configuration
13409 Data type representing the configuration of the Kerberos 5 PAM module
13410 This type has the following parameters:
13412 @item @code{pam-krb5} (default: @code{pam-krb5})
13413 The pam-krb5 package to use.
13415 @item @code{minimum-uid} (default: @code{1000})
13416 The smallest user ID for which Kerberos authentications should be attempted.
13417 Local accounts with lower values will silently fail to authenticate.
13423 @subsubsection Web Services
13428 The @code{(gnu services web)} module provides the following service:
13430 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13431 [#:log-directory ``/var/log/nginx''] @
13432 [#:run-directory ``/var/run/nginx''] @
13433 [#:server-list '()] @
13434 [#:upstream-list '()] @
13435 [#:config-file @code{#f}]
13437 Return a service that runs @var{nginx}, the nginx web server.
13439 The nginx daemon loads its runtime configuration from @var{config-file}.
13440 Log files are written to @var{log-directory} and temporary runtime data
13441 files are written to @var{run-directory}. For proper operation, these
13442 arguments should match what is in @var{config-file} to ensure that the
13443 directories are created when the service is activated.
13445 As an alternative to using a @var{config-file}, @var{server-list} can be
13446 used to specify the list of @dfn{server blocks} required on the host and
13447 @var{upstream-list} can be used to specify a list of @dfn{upstream
13448 blocks} to configure. For this to work, use the default value for
13451 At startup, @command{nginx} has not yet read its configuration file, so it
13452 uses a default file to log error messages. If it fails to load its
13453 configuration file, that is where error messages are logged. After the
13454 configuration file is loaded, the default error log file changes as per
13455 configuration. In our case, startup error messages can be found in
13456 @file{/var/run/nginx/logs/error.log}, and after configuration in
13457 @file{/var/log/nginx/error.log}. The second location can be changed with the
13458 @var{log-directory} configuration option.
13462 @deffn {Scheme Variable} nginx-service-type
13463 This is type for the nginx web server.
13465 This service can be extended to add server blocks in addition to the
13466 default one, as in this example:
13469 (simple-service 'my-extra-server nginx-service-type
13470 (list (nginx-server-configuration
13472 (root "/srv/http/extra-website"))))
13476 @deftp {Data Type} nginx-server-configuration
13477 Data type representing the configuration of an nginx server block.
13478 This type has the following parameters:
13481 @item @code{http-port} (default: @code{80})
13482 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13483 nginx should not listen for HTTP (non secure) connection for this
13484 @dfn{server block}.
13486 @item @code{https-port} (default: @code{443})
13487 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13488 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13490 Note that nginx can listen for HTTP and HTTPS connections in the same
13491 @dfn{server block}.
13493 @item @code{server-name} (default: @code{(list 'default)})
13494 A list of server names this server represents. @code{'default} represents the
13495 default server for connections matching no other server.
13497 @item @code{root} (default: @code{"/srv/http"})
13498 Root of the website nginx will serve.
13500 @item @code{locations} (default: @code{'()})
13501 A list of @dfn{nginx-location-configuration} or
13502 @dfn{nginx-named-location-configuration} records to use within this
13505 @item @code{index} (default: @code{(list "index.html")})
13506 Index files to look for when clients ask for a directory. If it cannot be found,
13507 Nginx will send the list of files in the directory.
13509 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13510 Where to find the certificate for secure connections. Set it to @code{#f} if
13511 you don't have a certificate or you don't want to use HTTPS.
13513 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13514 Where to find the private key for secure connections. Set it to @code{#f} if
13515 you don't have a key or you don't want to use HTTPS.
13517 @item @code{server-tokens?} (default: @code{#f})
13518 Whether the server should add its configuration to response.
13524 @subsubsection VPN Services
13525 @cindex VPN (virtual private network)
13526 @cindex virtual private network (VPN)
13528 The @code{(gnu services vpn)} module provides services related to
13529 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
13530 your machine to connect to a VPN, and a @emph{servire} service for your machine
13531 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
13533 @deffn {Scheme Procedure} openvpn-client-service @
13534 [#:config (openvpn-client-configuration)]
13536 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
13539 @deffn {Scheme Procedure} openvpn-server-service @
13540 [#:config (openvpn-server-configuration)]
13542 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
13544 Both can be run simultaneously.
13547 @c %automatically generated documentation
13549 Available @code{openvpn-client-configuration} fields are:
13551 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
13552 The OpenVPN package.
13556 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
13557 The OpenVPN pid file.
13559 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13563 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
13564 The protocol (UDP or TCP) used to open a channel between clients and
13567 Defaults to @samp{udp}.
13571 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
13572 The device type used to represent the VPN connection.
13574 Defaults to @samp{tun}.
13578 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
13579 The certificate authority to check connections against.
13581 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13585 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
13586 The certificate of the machine the daemon is running on. It should be
13587 signed by the authority given in @code{ca}.
13589 Defaults to @samp{"/etc/openvpn/client.crt"}.
13593 @deftypevr {@code{openvpn-client-configuration} parameter} string key
13594 The key of the machine the daemon is running on. It must be the key whose
13595 certificate is @code{cert}.
13597 Defaults to @samp{"/etc/openvpn/client.key"}.
13601 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
13602 Whether to use the lzo compression algorithm.
13604 Defaults to @samp{#t}.
13608 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
13609 Don't re-read key files across SIGUSR1 or --ping-restart.
13611 Defaults to @samp{#t}.
13615 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
13616 Don't close and reopen TUN/TAP device or run up/down scripts across
13617 SIGUSR1 or --ping-restart restarts.
13619 Defaults to @samp{#t}.
13623 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
13626 Defaults to @samp{3}.
13630 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
13631 Add an additional layer of HMAC authentication on top of the TLS control
13632 channel to protect against DoS attacks.
13634 Defaults to @samp{#f}.
13638 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
13639 Whether to check the server certificate has server usage extension.
13641 Defaults to @samp{#t}.
13645 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
13646 Bind to a specific local port number.
13648 Defaults to @samp{#f}.
13652 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
13653 Retry resolving server address.
13655 Defaults to @samp{#t}.
13659 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
13660 A list of remote servers to connect to.
13662 Defaults to @samp{()}.
13664 Available @code{openvpn-remote-configuration} fields are:
13666 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
13669 Defaults to @samp{"my-server"}.
13673 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
13674 Port number the server listens to.
13676 Defaults to @samp{1194}.
13681 @c %end of automatic openvpn-client documentation
13683 @c %automatically generated documentation
13685 Available @code{openvpn-server-configuration} fields are:
13687 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
13688 The OpenVPN package.
13692 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
13693 The OpenVPN pid file.
13695 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13699 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
13700 The protocol (UDP or TCP) used to open a channel between clients and
13703 Defaults to @samp{udp}.
13707 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
13708 The device type used to represent the VPN connection.
13710 Defaults to @samp{tun}.
13714 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
13715 The certificate authority to check connections against.
13717 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13721 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
13722 The certificate of the machine the daemon is running on. It should be
13723 signed by the authority given in @code{ca}.
13725 Defaults to @samp{"/etc/openvpn/client.crt"}.
13729 @deftypevr {@code{openvpn-server-configuration} parameter} string key
13730 The key of the machine the daemon is running on. It must be the key whose
13731 certificate is @code{cert}.
13733 Defaults to @samp{"/etc/openvpn/client.key"}.
13737 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
13738 Whether to use the lzo compression algorithm.
13740 Defaults to @samp{#t}.
13744 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
13745 Don't re-read key files across SIGUSR1 or --ping-restart.
13747 Defaults to @samp{#t}.
13751 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
13752 Don't close and reopen TUN/TAP device or run up/down scripts across
13753 SIGUSR1 or --ping-restart restarts.
13755 Defaults to @samp{#t}.
13759 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
13762 Defaults to @samp{3}.
13766 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
13767 Add an additional layer of HMAC authentication on top of the TLS control
13768 channel to protect against DoS attacks.
13770 Defaults to @samp{#f}.
13774 @deftypevr {@code{openvpn-server-configuration} parameter} number port
13775 Specifies the port number on which the server listens.
13777 Defaults to @samp{1194}.
13781 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
13782 An ip and mask specifying the subnet inside the virtual network.
13784 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
13788 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
13789 A CIDR notation specifying the IPv6 subnet inside the virtual network.
13791 Defaults to @samp{#f}.
13795 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
13796 The Diffie-Hellman parameters file.
13798 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
13802 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
13803 The file that records client IPs.
13805 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
13809 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
13810 When true, the server will act as a gateway for its clients.
13812 Defaults to @samp{#f}.
13816 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
13817 When true, clients are allowed to talk to each other inside the VPN.
13819 Defaults to @samp{#f}.
13823 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
13824 Causes ping-like messages to be sent back and forth over the link so
13825 that each side knows when the other side has gone down. @code{keepalive}
13826 requires a pair. The first element is the period of the ping sending,
13827 and the second element is the timeout before considering the other side
13832 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
13833 The maximum number of clients.
13835 Defaults to @samp{100}.
13839 @deftypevr {@code{openvpn-server-configuration} parameter} string status
13840 The status file. This file shows a small report on current connection.
13841 It is truncated and rewritten every minute.
13843 Defaults to @samp{"/var/run/openvpn/status"}.
13847 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
13848 The list of configuration for some clients.
13850 Defaults to @samp{()}.
13852 Available @code{openvpn-ccd-configuration} fields are:
13854 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
13857 Defaults to @samp{"client"}.
13861 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
13864 Defaults to @samp{#f}.
13868 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
13871 Defaults to @samp{#f}.
13878 @c %end of automatic openvpn-server documentation
13881 @deftp {Data Type} nginx-upstream-configuration
13882 Data type representing the configuration of an nginx @code{upstream}
13883 block. This type has the following parameters:
13887 Name for this group of servers.
13889 @item @code{servers}
13890 Specify the addresses of the servers in the group. The address can be
13891 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13892 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13893 prefix @samp{unix:}. For addresses using an IP address or domain name,
13894 the default port is 80, and a different port can be specified
13900 @deftp {Data Type} nginx-location-configuration
13901 Data type representing the configuration of an nginx @code{location}
13902 block. This type has the following parameters:
13906 URI which this location block matches.
13908 @anchor{nginx-location-configuration body}
13910 Body of the location block, specified as a string. This can contain many
13911 configuration directives. For example, to pass requests to a upstream
13912 server group defined using an @code{nginx-upstream-configuration} block,
13913 the following directive would be specified in the body @samp{proxy_pass
13914 http://upstream-name;}.
13919 @deftp {Data Type} nginx-named-location-configuration
13920 Data type representing the configuration of an nginx named location
13921 block. Named location blocks are used for request redirection, and not
13922 used for regular request processing. This type has the following
13927 Name to identify this location block.
13930 @xref{nginx-location-configuration body}, as the body for named location
13931 blocks can be used in a similar way to the
13932 @code{nginx-location-configuration body}. One restriction is that the
13933 body of a named location block cannot contain location blocks.
13938 @node Network File System
13939 @subsubsection Network File System
13942 The @code{(gnu services nfs)} module provides the following services,
13943 which are most commonly used in relation to mounting or exporting
13944 directory trees as @dfn{network file systems} (NFS).
13946 @subsubheading RPC Bind Service
13949 The RPC Bind service provides a facility to map program numbers into
13950 universal addresses.
13951 Many NFS related services use this facility. Hence it is automatically
13952 started when a dependent service starts.
13954 @defvr {Scheme Variable} rpcbind-service-type
13955 A service type for the RPC portmapper daemon.
13959 @deftp {Data Type} rpcbind-configuration
13960 Data type representing the configuration of the RPC Bind Service.
13961 This type has the following parameters:
13963 @item @code{rpcbind} (default: @code{rpcbind})
13964 The rpcbind package to use.
13966 @item @code{warm-start?} (default: @code{#t})
13967 If this parameter is @code{#t}, then the daemon will read a
13968 state file on startup thus reloading state information saved by a previous
13974 @subsubheading Pipefs Pseudo File System
13978 The pipefs file system is used to transfer NFS related data
13979 between the kernel and user space programs.
13981 @defvr {Scheme Variable} pipefs-service-type
13982 A service type for the pipefs pseudo file system.
13985 @deftp {Data Type} pipefs-configuration
13986 Data type representing the configuration of the pipefs pseudo file system service.
13987 This type has the following parameters:
13989 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13990 The directory to which the file system is to be attached.
13995 @subsubheading GSS Daemon Service
13998 @cindex global security system
14000 The @dfn{global security system} (GSS) daemon provides strong security for RPC
14002 Before exchanging RPC requests an RPC client must establish a security
14003 context. Typically this is done using the Kerberos command @command{kinit}
14004 or automatically at login time using PAM services (@pxref{Kerberos Services}).
14006 @defvr {Scheme Variable} gss-service-type
14007 A service type for the Global Security System (GSS) daemon.
14010 @deftp {Data Type} gss-configuration
14011 Data type representing the configuration of the GSS daemon service.
14012 This type has the following parameters:
14014 @item @code{nfs-utils} (default: @code{nfs-utils})
14015 The package in which the @command{rpc.gssd} command is to be found.
14017 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14018 The directory where the pipefs file system is mounted.
14024 @subsubheading IDMAP Daemon Service
14026 @cindex name mapper
14028 The idmap daemon service provides mapping between user IDs and user names.
14029 Typically it is required in order to access file systems mounted via NFSv4.
14031 @defvr {Scheme Variable} idmap-service-type
14032 A service type for the Identity Mapper (IDMAP) daemon.
14035 @deftp {Data Type} idmap-configuration
14036 Data type representing the configuration of the IDMAP daemon service.
14037 This type has the following parameters:
14039 @item @code{nfs-utils} (default: @code{nfs-utils})
14040 The package in which the @command{rpc.idmapd} command is to be found.
14042 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
14043 The directory where the pipefs file system is mounted.
14045 @item @code{domain} (default: @code{#f})
14046 The local NFSv4 domain name.
14047 This must be a string or @code{#f}.
14048 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
14053 @node Continuous Integration
14054 @subsubsection Continuous Integration
14056 @cindex continuous integration
14057 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
14058 integration tool for Guix. It can be used both for development and for
14059 providing substitutes to others (@pxref{Substitutes}).
14061 The @code{(gnu services cuirass)} module provides the following service.
14063 @defvr {Scheme Procedure} cuirass-service-type
14064 The type of the Cuirass service. Its value must be a
14065 @code{cuirass-configuration} object, as described below.
14068 To add build jobs, you have to set the @code{specifications} field of
14069 the configuration. Here is an example of a service defining a build job
14070 based on a specification that can be found in Cuirass source tree. This
14071 service polls the Guix repository and builds a subset of the Guix
14072 packages, as prescribed in the @file{gnu-system.scm} example spec:
14075 (let ((spec #~((#:name . "guix")
14076 (#:url . "git://git.savannah.gnu.org/guix.git")
14077 (#:load-path . ".")
14079 ;; Here we must provide an absolute file name.
14080 ;; We take jobs from one of the examples provided
14082 (#:file . #$(file-append
14084 "/tests/gnu-system.scm"))
14086 (#:proc . hydra-jobs)
14087 (#:arguments (subset . "hello"))
14088 (#:branch . "master"))))
14089 (service cuirass-service-type
14090 (cuirass-configuration
14091 (specifications #~(list #$spec)))))
14094 While information related to build jobs is located directly in the
14095 specifications, global settings for the @command{cuirass} process are
14096 accessible in other @code{cuirass-configuration} fields.
14098 @deftp {Data Type} cuirass-configuration
14099 Data type representing the configuration of Cuirass.
14102 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
14103 Location of the log file.
14105 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
14106 Location of the repository cache.
14108 @item @code{user} (default: @code{"cuirass"})
14109 Owner of the @code{cuirass} process.
14111 @item @code{group} (default: @code{"cuirass"})
14112 Owner's group of the @code{cuirass} process.
14114 @item @code{interval} (default: @code{60})
14115 Number of seconds between the poll of the repositories followed by the
14118 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
14119 Location of sqlite database which contains the build results and previously
14120 added specifications.
14122 @item @code{port} (default: @code{8080})
14123 Port number used by the HTTP server.
14125 @item @code{specifications} (default: @code{#~'()})
14126 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
14127 where a specification is an association list
14128 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
14129 keys are keywords (@code{#:keyword-example}) as shown in the example
14132 @item @code{use-substitutes?} (default: @code{#f})
14133 This allows using substitutes to avoid building every dependencies of a job
14136 @item @code{one-shot?} (default: @code{#f})
14137 Only evaluate specifications and build derivations once.
14139 @item @code{load-path} (default: @code{'()})
14140 This allows users to define their own packages and make them visible to
14141 cuirass as in @command{guix build} command.
14143 @item @code{cuirass} (default: @code{cuirass})
14144 The Cuirass package to use.
14148 @node Power management Services
14149 @subsubsection Power management Services
14151 @cindex power management with TLP
14152 The @code{(gnu services pm)} module provides a Guix service definition
14153 for the Linux power management tool TLP.
14155 TLP enables various powersaving modes in userspace and kernel.
14156 Contrary to @code{upower-service}, it is not a passive,
14157 monitoring tool, as it will apply custom settings each time a new power
14158 source is detected. More information can be found at
14159 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14161 @deffn {Scheme Variable} tlp-service-type
14162 The service type for the TLP tool. Its value should be a valid
14163 TLP configuration (see below). To use the default settings, simply
14166 (service tlp-service-type)
14170 By default TLP does not need much configuration but most TLP parameters
14171 can be tweaked using @code{tlp-configuration}.
14173 Each parameter definition is preceded by its type; for example,
14174 @samp{boolean foo} indicates that the @code{foo} parameter
14175 should be specified as a boolean. Types starting with
14176 @code{maybe-} denote parameters that won't show up in TLP config file
14177 when their value is @code{'disabled}.
14179 @c The following documentation was initially generated by
14180 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14181 @c documentation is better, so we shouldn't hesitate to edit below as
14182 @c needed. However if the change you want to make to this documentation
14183 @c can be done in an automated way, it's probably easier to change
14184 @c (generate-documentation) than to make it below and have to deal with
14185 @c the churn as TLP updates.
14187 Available @code{tlp-configuration} fields are:
14189 @deftypevr {@code{tlp-configuration} parameter} package tlp
14194 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14195 Set to true if you wish to enable TLP.
14197 Defaults to @samp{#t}.
14201 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14202 Default mode when no power supply can be detected. Alternatives are AC
14205 Defaults to @samp{"AC"}.
14209 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14210 Number of seconds Linux kernel has to wait after the disk goes idle,
14211 before syncing on AC.
14213 Defaults to @samp{0}.
14217 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14218 Same as @code{disk-idle-ac} but on BAT mode.
14220 Defaults to @samp{2}.
14224 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14225 Dirty pages flushing periodicity, expressed in seconds.
14227 Defaults to @samp{15}.
14231 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14232 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14234 Defaults to @samp{60}.
14238 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14239 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14240 alternatives are powersave and performance. With acpi-cpufreq driver,
14241 alternatives are ondemand, powersave, performance and conservative.
14243 Defaults to @samp{disabled}.
14247 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14248 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14250 Defaults to @samp{disabled}.
14254 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14255 Set the min available frequency for the scaling governor on AC.
14257 Defaults to @samp{disabled}.
14261 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14262 Set the max available frequency for the scaling governor on AC.
14264 Defaults to @samp{disabled}.
14268 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14269 Set the min available frequency for the scaling governor on BAT.
14271 Defaults to @samp{disabled}.
14275 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14276 Set the max available frequency for the scaling governor on BAT.
14278 Defaults to @samp{disabled}.
14282 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14283 Limit the min P-state to control the power dissipation of the CPU, in AC
14284 mode. Values are stated as a percentage of the available performance.
14286 Defaults to @samp{disabled}.
14290 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14291 Limit the max P-state to control the power dissipation of the CPU, in AC
14292 mode. Values are stated as a percentage of the available performance.
14294 Defaults to @samp{disabled}.
14298 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14299 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14301 Defaults to @samp{disabled}.
14305 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14306 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14308 Defaults to @samp{disabled}.
14312 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14313 Enable CPU turbo boost feature on AC mode.
14315 Defaults to @samp{disabled}.
14319 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14320 Same as @code{cpu-boost-on-ac?} on BAT mode.
14322 Defaults to @samp{disabled}.
14326 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14327 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14328 used under light load conditions.
14330 Defaults to @samp{#f}.
14334 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14335 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14337 Defaults to @samp{#t}.
14341 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14342 Enable Linux kernel NMI watchdog.
14344 Defaults to @samp{#f}.
14348 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14349 For Linux kernels with PHC patch applied, change CPU voltages. An
14350 example value would be @samp{"F:V F:V F:V F:V"}.
14352 Defaults to @samp{disabled}.
14356 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14357 Set CPU performance versus energy saving policy on AC. Alternatives are
14358 performance, normal, powersave.
14360 Defaults to @samp{"performance"}.
14364 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14365 Same as @code{energy-perf-policy-ac} but on BAT mode.
14367 Defaults to @samp{"powersave"}.
14371 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14376 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14377 Hard disk advanced power management level.
14381 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14382 Same as @code{disk-apm-bat} but on BAT mode.
14386 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14387 Hard disk spin down timeout. One value has to be specified for each
14388 declared hard disk.
14390 Defaults to @samp{disabled}.
14394 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14395 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14397 Defaults to @samp{disabled}.
14401 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14402 Select IO scheduler for disk devices. One value has to be specified for
14403 each declared hard disk. Example alternatives are cfq, deadline and
14406 Defaults to @samp{disabled}.
14410 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14411 SATA aggressive link power management (ALPM) level. Alternatives are
14412 min_power, medium_power, max_performance.
14414 Defaults to @samp{"max_performance"}.
14418 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14419 Same as @code{sata-linkpwr-ac} but on BAT mode.
14421 Defaults to @samp{"min_power"}.
14425 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14426 Exclude specified SATA host devices for link power management.
14428 Defaults to @samp{disabled}.
14432 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14433 Enable Runtime Power Management for AHCI controller and disks on AC
14436 Defaults to @samp{disabled}.
14440 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14441 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14443 Defaults to @samp{disabled}.
14447 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14448 Seconds of inactivity before disk is suspended.
14450 Defaults to @samp{15}.
14454 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14455 PCI Express Active State Power Management level. Alternatives are
14456 default, performance, powersave.
14458 Defaults to @samp{"performance"}.
14462 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14463 Same as @code{pcie-aspm-ac} but on BAT mode.
14465 Defaults to @samp{"powersave"}.
14469 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14470 Radeon graphics clock speed level. Alternatives are low, mid, high,
14473 Defaults to @samp{"high"}.
14477 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14478 Same as @code{radeon-power-ac} but on BAT mode.
14480 Defaults to @samp{"low"}.
14484 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14485 Radeon dynamic power management method (DPM). Alternatives are battery,
14488 Defaults to @samp{"performance"}.
14492 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14493 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14495 Defaults to @samp{"battery"}.
14499 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14500 Radeon DPM performance level. Alternatives are auto, low, high.
14502 Defaults to @samp{"auto"}.
14506 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14507 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14509 Defaults to @samp{"auto"}.
14513 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14514 Wifi power saving mode.
14516 Defaults to @samp{#f}.
14520 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14521 Same as @code{wifi-power-ac?} but on BAT mode.
14523 Defaults to @samp{#t}.
14527 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14528 Disable wake on LAN.
14530 Defaults to @samp{#t}.
14534 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14535 Timeout duration in seconds before activating audio power saving on
14536 Intel HDA and AC97 devices. A value of 0 disables power saving.
14538 Defaults to @samp{0}.
14542 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14543 Same as @code{sound-powersave-ac} but on BAT mode.
14545 Defaults to @samp{1}.
14549 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
14550 Disable controller in powersaving mode on Intel HDA devices.
14552 Defaults to @samp{#t}.
14556 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
14557 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
14558 powered on again by releasing (and reinserting) the eject lever or by
14559 pressing the disc eject button on newer models.
14561 Defaults to @samp{#f}.
14565 @deftypevr {@code{tlp-configuration} parameter} string bay-device
14566 Name of the optical drive device to power off.
14568 Defaults to @samp{"sr0"}.
14572 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
14573 Runtime Power Management for PCI(e) bus devices. Alternatives are on
14576 Defaults to @samp{"on"}.
14580 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
14581 Same as @code{runtime-pm-ac} but on BAT mode.
14583 Defaults to @samp{"auto"}.
14587 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
14588 Runtime Power Management for all PCI(e) bus devices, except blacklisted
14591 Defaults to @samp{#t}.
14595 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
14596 Exclude specified PCI(e) device addresses from Runtime Power Management.
14598 Defaults to @samp{disabled}.
14602 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
14603 Exclude PCI(e) devices assigned to the specified drivers from Runtime
14608 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
14609 Enable USB autosuspend feature.
14611 Defaults to @samp{#t}.
14615 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
14616 Exclude specified devices from USB autosuspend.
14618 Defaults to @samp{disabled}.
14622 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
14623 Exclude WWAN devices from USB autosuspend.
14625 Defaults to @samp{#t}.
14629 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
14630 Include specified devices into USB autosuspend, even if they are already
14631 excluded by the driver or via @code{usb-blacklist-wwan?}.
14633 Defaults to @samp{disabled}.
14637 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
14638 Enable USB autosuspend before shutdown.
14640 Defaults to @samp{disabled}.
14644 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
14645 Restore radio device state (bluetooth, wifi, wwan) from previous
14646 shutdown on system startup.
14648 Defaults to @samp{#f}.
14653 The @code{(gnu services pm)} module provides an interface to
14654 thermald, a CPU frequency scaling service which helps prevent overheating.
14656 @defvr {Scheme Variable} thermald-service-type
14657 This is the service type for
14658 @uref{https://01.org/linux-thermal-daemon/, thermald}, the Linux
14659 Thermal Daemon, which is responsible for controlling the thermal state
14660 of processors and preventing overheating.
14663 @deftp {Data Type} thermald-configuration
14664 Data type representing the configuration of @code{thermald-service-type}.
14667 @item @code{ignore-cpuid-check?} (default: @code{#f})
14668 Ignore cpuid check for supported CPU models.
14670 @item @code{thermald} (default: @var{thermald})
14671 Package object of thermald.
14677 @node Miscellaneous Services
14678 @subsubsection Miscellaneous Services
14682 @subsubheading Lirc Service
14684 The @code{(gnu services lirc)} module provides the following service.
14686 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
14687 [#:device #f] [#:driver #f] [#:config-file #f] @
14688 [#:extra-options '()]
14689 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
14690 decodes infrared signals from remote controls.
14692 Optionally, @var{device}, @var{driver} and @var{config-file}
14693 (configuration file name) may be specified. See @command{lircd} manual
14696 Finally, @var{extra-options} is a list of additional command-line options
14697 passed to @command{lircd}.
14701 @subsubheading Spice Service
14703 The @code{(gnu services spice)} module provides the following service.
14705 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
14706 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
14707 that enables sharing the clipboard with a vm and setting the guest display
14708 resolution when the graphical console window resizes.
14711 @subsubsection Dictionary Services
14713 The @code{(gnu services dict)} module provides the following service:
14715 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
14716 Return a service that runs the @command{dicod} daemon, an implementation
14717 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
14719 The optional @var{config} argument specifies the configuration for
14720 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
14721 default it serves the GNU Collaborative International Dictonary of English.
14723 You can add @command{open localhost} to your @file{~/.dico} file to make
14724 @code{localhost} the default server for @command{dico} client
14725 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
14728 @deftp {Data Type} dicod-configuration
14729 Data type representing the configuration of dicod.
14732 @item @code{dico} (default: @var{dico})
14733 Package object of the GNU Dico dictionary server.
14735 @item @code{interfaces} (default: @var{'("localhost")})
14736 This is the list of IP addresses and ports and possibly socket file
14737 names to listen to (@pxref{Server Settings, @code{listen} directive,,
14738 dico, GNU Dico Manual}).
14740 @item @code{handlers} (default: @var{'()})
14741 List of @code{<dicod-handler>} objects denoting handlers (module instances).
14743 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
14744 List of @code{<dicod-database>} objects denoting dictionaries to be served.
14748 @deftp {Data Type} dicod-handler
14749 Data type representing a dictionary handler (module instance).
14753 Name of the handler (module instance).
14755 @item @code{module} (default: @var{#f})
14756 Name of the dicod module of the handler (instance). If it is @code{#f},
14757 the module has the same name as the handler.
14758 (@pxref{Modules,,, dico, GNU Dico Manual}).
14760 @item @code{options}
14761 List of strings or gexps representing the arguments for the module handler
14765 @deftp {Data Type} dicod-database
14766 Data type representing a dictionary database.
14770 Name of the database, will be used in DICT commands.
14772 @item @code{handler}
14773 Name of the dicod handler (module instance) used by this database
14774 (@pxref{Handlers,,, dico, GNU Dico Manual}).
14776 @item @code{complex?} (default: @var{#f})
14777 Whether the database configuration complex. The complex configuration
14778 will need a corresponding @code{<dicod-handler>} object, otherwise not.
14780 @item @code{options}
14781 List of strings or gexps representing the arguments for the database
14782 (@pxref{Databases,,, dico, GNU Dico Manual}).
14786 @defvr {Scheme Variable} %dicod-database:gcide
14787 A @code{<dicod-database>} object serving the GNU Collaborative International
14788 Dictionary of English using the @code{gcide} package.
14791 The following is an example @code{dicod-service} configuration.
14794 (dicod-service #:config
14795 (dicod-configuration
14796 (handlers (list (dicod-handler
14800 (list #~(string-append "dbdir=" #$wordnet))))))
14801 (databases (list (dicod-database
14804 (handler "wordnet")
14805 (options '("database=wn")))
14806 %dicod-database:gcide))))
14809 @subsubsection Version Control
14811 The @code{(gnu services version-control)} module provides the following services:
14813 @subsubheading Git daemon service
14815 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
14817 Return a service that runs @command{git daemon}, a simple TCP server to
14818 expose repositories over the Git protocol for anonymous access.
14820 The optional @var{config} argument should be a
14821 @code{<git-daemon-configuration>} object, by default it allows read-only
14822 access to exported@footnote{By creating the magic file
14823 "git-daemon-export-ok" in the repository directory.} repositories under
14828 @deftp {Data Type} git-daemon-configuration
14829 Data type representing the configuration for @code{git-daemon-service}.
14832 @item @code{package} (default: @var{git})
14833 Package object of the Git distributed version control system.
14835 @item @code{export-all?} (default: @var{#f})
14836 Whether to allow access for all Git repositories, even if they do not
14837 have the @file{git-daemon-export-ok} file.
14839 @item @code{base-path} (default: @file{/srv/git})
14840 Whether to remap all the path requests as relative to the given path.
14841 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
14842 then if you later try to pull @code{git://example.com/hello.git}, git
14843 daemon will interpret the path as @code{/srv/git/hello.git}.
14845 @item @code{user-path} (default: @var{#f})
14846 Whether to allow @code{~user} notation to be used in requests. When
14847 specified with empty string, requests to @code{git://host/~alice/foo} is
14848 taken as a request to access @code{foo} repository in the home directory
14849 of user @code{alice}. If @var{(user-path "path")} is specified, the
14850 same request is taken as a request to access @code{path/foo} repository
14851 in the home directory of user @code{alice}.
14853 @item @code{listen} (default: @var{'()})
14854 Whether to listen on specific IP addresses or hostnames, defaults to
14857 @item @code{port} (default: @var{#f})
14858 Whether to listen on an alternative port, which defaults to 9418.
14860 @item @code{whitelist} (default: @var{'()})
14861 If not empty, only allow access to this list of directories.
14863 @item @code{extra-options} (default: @var{'()})
14864 Extra options will be passed to @code{git daemon}, please run
14865 @command{man git-daemon} for more information.
14870 @node Setuid Programs
14871 @subsection Setuid Programs
14873 @cindex setuid programs
14874 Some programs need to run with ``root'' privileges, even when they are
14875 launched by unprivileged users. A notorious example is the
14876 @command{passwd} program, which users can run to change their
14877 password, and which needs to access the @file{/etc/passwd} and
14878 @file{/etc/shadow} files---something normally restricted to root, for
14879 obvious security reasons. To address that, these executables are
14880 @dfn{setuid-root}, meaning that they always run with root privileges
14881 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
14882 for more info about the setuid mechanism.)
14884 The store itself @emph{cannot} contain setuid programs: that would be a
14885 security issue since any user on the system can write derivations that
14886 populate the store (@pxref{The Store}). Thus, a different mechanism is
14887 used: instead of changing the setuid bit directly on files that are in
14888 the store, we let the system administrator @emph{declare} which programs
14889 should be setuid root.
14891 The @code{setuid-programs} field of an @code{operating-system}
14892 declaration contains a list of G-expressions denoting the names of
14893 programs to be setuid-root (@pxref{Using the Configuration System}).
14894 For instance, the @command{passwd} program, which is part of the Shadow
14895 package, can be designated by this G-expression (@pxref{G-Expressions}):
14898 #~(string-append #$shadow "/bin/passwd")
14901 A default set of setuid programs is defined by the
14902 @code{%setuid-programs} variable of the @code{(gnu system)} module.
14904 @defvr {Scheme Variable} %setuid-programs
14905 A list of G-expressions denoting common programs that are setuid-root.
14907 The list includes commands such as @command{passwd}, @command{ping},
14908 @command{su}, and @command{sudo}.
14911 Under the hood, the actual setuid programs are created in the
14912 @file{/run/setuid-programs} directory at system activation time. The
14913 files in this directory refer to the ``real'' binaries, which are in the
14916 @node X.509 Certificates
14917 @subsection X.509 Certificates
14919 @cindex HTTPS, certificates
14920 @cindex X.509 certificates
14922 Web servers available over HTTPS (that is, HTTP over the transport-layer
14923 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
14924 that the client can then use to @emph{authenticate} the server. To do
14925 that, clients verify that the server's certificate is signed by a
14926 so-called @dfn{certificate authority} (CA). But to verify the CA's
14927 signature, clients must have first acquired the CA's certificate.
14929 Web browsers such as GNU@tie{}IceCat include their own set of CA
14930 certificates, such that they are able to verify CA signatures
14933 However, most other programs that can talk HTTPS---@command{wget},
14934 @command{git}, @command{w3m}, etc.---need to be told where CA
14935 certificates can be found.
14937 @cindex @code{nss-certs}
14938 In GuixSD, this is done by adding a package that provides certificates
14939 to the @code{packages} field of the @code{operating-system} declaration
14940 (@pxref{operating-system Reference}). GuixSD includes one such package,
14941 @code{nss-certs}, which is a set of CA certificates provided as part of
14942 Mozilla's Network Security Services.
14944 Note that it is @emph{not} part of @var{%base-packages}, so you need to
14945 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
14946 most applications and libraries look for certificates by default, points
14947 to the certificates installed globally.
14949 Unprivileged users, including users of Guix on a foreign distro,
14950 can also install their own certificate package in
14951 their profile. A number of environment variables need to be defined so
14952 that applications and libraries know where to find them. Namely, the
14953 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
14954 variables. Some applications add their own environment variables; for
14955 instance, the Git version control system honors the certificate bundle
14956 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
14957 would typically run something like:
14960 $ guix package -i nss-certs
14961 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
14962 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14963 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
14966 As another example, R requires the @code{CURL_CA_BUNDLE} environment
14967 variable to point to a certificate bundle, so you would have to run
14968 something like this:
14971 $ guix package -i nss-certs
14972 $ export CURL_CA_BUNDLE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14975 For other applications you may want to look up the required environment
14976 variable in the relevant documentation.
14979 @node Name Service Switch
14980 @subsection Name Service Switch
14982 @cindex name service switch
14984 The @code{(gnu system nss)} module provides bindings to the
14985 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
14986 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
14987 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
14988 extended with new ``name'' lookup methods for system databases, which
14989 includes host names, service names, user accounts, and more (@pxref{Name
14990 Service Switch, System Databases and Name Service Switch,, libc, The GNU
14991 C Library Reference Manual}).
14993 The NSS configuration specifies, for each system database, which lookup
14994 method is to be used, and how the various methods are chained
14995 together---for instance, under which circumstances NSS should try the
14996 next method in the list. The NSS configuration is given in the
14997 @code{name-service-switch} field of @code{operating-system} declarations
14998 (@pxref{operating-system Reference, @code{name-service-switch}}).
15001 @cindex .local, host name lookup
15002 As an example, the declaration below configures the NSS to use the
15003 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
15004 back-end}, which supports host name lookups over multicast DNS (mDNS)
15005 for host names ending in @code{.local}:
15008 (name-service-switch
15009 (hosts (list %files ;first, check /etc/hosts
15011 ;; If the above did not succeed, try
15012 ;; with 'mdns_minimal'.
15014 (name "mdns_minimal")
15016 ;; 'mdns_minimal' is authoritative for
15017 ;; '.local'. When it returns "not found",
15018 ;; no need to try the next methods.
15019 (reaction (lookup-specification
15020 (not-found => return))))
15022 ;; Then fall back to DNS.
15026 ;; Finally, try with the "full" 'mdns'.
15031 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
15032 contains this configuration, so you will not have to type it if all you
15033 want is to have @code{.local} host lookup working.
15035 Note that, in this case, in addition to setting the
15036 @code{name-service-switch} of the @code{operating-system} declaration,
15037 you also need to use @code{avahi-service} (@pxref{Networking Services,
15038 @code{avahi-service}}), or @var{%desktop-services}, which includes it
15039 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
15040 to the name service cache daemon (@pxref{Base Services,
15041 @code{nscd-service}}).
15043 For convenience, the following variables provide typical NSS
15046 @defvr {Scheme Variable} %default-nss
15047 This is the default name service switch configuration, a
15048 @code{name-service-switch} object.
15051 @defvr {Scheme Variable} %mdns-host-lookup-nss
15052 This is the name service switch configuration with support for host name
15053 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
15056 The reference for name service switch configuration is given below. It
15057 is a direct mapping of the configuration file format of the C library , so
15058 please refer to the C library manual for more information (@pxref{NSS
15059 Configuration File,,, libc, The GNU C Library Reference Manual}).
15060 Compared to the configuration file format of libc NSS, it has the advantage
15061 not only of adding this warm parenthetic feel that we like, but also
15062 static checks: you will know about syntax errors and typos as soon as you
15063 run @command{guix system}.
15065 @deftp {Data Type} name-service-switch
15067 This is the data type representation the configuration of libc's name
15068 service switch (NSS). Each field below represents one of the supported
15085 The system databases handled by the NSS. Each of these fields must be a
15086 list of @code{<name-service>} objects (see below).
15090 @deftp {Data Type} name-service
15092 This is the data type representing an actual name service and the
15093 associated lookup action.
15097 A string denoting the name service (@pxref{Services in the NSS
15098 configuration,,, libc, The GNU C Library Reference Manual}).
15100 Note that name services listed here must be visible to nscd. This is
15101 achieved by passing the @code{#:name-services} argument to
15102 @code{nscd-service} the list of packages providing the needed name
15103 services (@pxref{Base Services, @code{nscd-service}}).
15106 An action specified using the @code{lookup-specification} macro
15107 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
15108 Reference Manual}). For example:
15111 (lookup-specification (unavailable => continue)
15112 (success => return))
15117 @node Initial RAM Disk
15118 @subsection Initial RAM Disk
15121 @cindex initial RAM disk
15122 For bootstrapping purposes, the Linux-Libre kernel is passed an
15123 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
15124 root file system as well as an initialization script. The latter is
15125 responsible for mounting the real root file system, and for loading any
15126 kernel modules that may be needed to achieve that.
15128 The @code{initrd} field of an @code{operating-system} declaration allows
15129 you to specify which initrd you would like to use. The @code{(gnu
15130 system linux-initrd)} module provides three ways to build an initrd: the
15131 high-level @code{base-initrd} procedure and the low-level
15132 @code{raw-initrd} and @code{expression->initrd} procedures.
15134 The @code{base-initrd} procedure is intended to cover most common uses.
15135 For example, if you want to add a bunch of kernel modules to be loaded
15136 at boot time, you can define the @code{initrd} field of the operating
15137 system declaration like this:
15140 (initrd (lambda (file-systems . rest)
15141 ;; Create a standard initrd that has modules "foo.ko"
15142 ;; and "bar.ko", as well as their dependencies, in
15143 ;; addition to the modules available by default.
15144 (apply base-initrd file-systems
15145 #:extra-modules '("foo" "bar")
15149 The @code{base-initrd} procedure also handles common use cases that
15150 involves using the system as a QEMU guest, or as a ``live'' system with
15151 volatile root file system.
15153 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
15154 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
15155 such as trying to guess which kernel modules and packages should be included
15156 to the initrd. An example use of @code{raw-initrd} is when a user has
15157 a custom Linux kernel configuration and default kernel modules included by
15158 @code{base-initrd} are not available.
15160 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
15161 honors several options passed on the Linux kernel command line
15162 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
15163 @code{-append} option of QEMU), notably:
15166 @item --load=@var{boot}
15167 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
15168 program, once it has mounted the root file system.
15170 GuixSD uses this option to yield control to a boot program that runs the
15171 service activation programs and then spawns the GNU@tie{}Shepherd, the
15172 initialization system.
15174 @item --root=@var{root}
15175 Mount @var{root} as the root file system. @var{root} can be a
15176 device name like @code{/dev/sda1}, a partition label, or a partition
15179 @item --system=@var{system}
15180 Have @file{/run/booted-system} and @file{/run/current-system} point to
15183 @item modprobe.blacklist=@var{modules}@dots{}
15184 @cindex module, black-listing
15185 @cindex black list, of kernel modules
15186 Instruct the initial RAM disk as well as the @command{modprobe} command
15187 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15188 must be a comma-separated list of module names---e.g.,
15189 @code{usbkbd,9pnet}.
15192 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15193 tries to load kernel modules and to mount the root file system. Our
15194 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15195 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15196 Manual}, for more information on Guile's REPL.
15200 Now that you know all the features that initial RAM disks produced by
15201 @code{base-initrd} and @code{raw-initrd} provide,
15202 here is how to use it and customize it further.
15205 @cindex initial RAM disk
15206 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15207 [#:linux-modules '()] [#:mapped-devices '()] @
15208 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15209 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15210 a list of file systems to be mounted by the initrd, possibly in addition to
15211 the root file system specified on the kernel command line via @code{--root}.
15212 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15213 @var{mapped-devices} is a list of device mappings to realize before
15214 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15215 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15216 include @code{e2fsck/static} or other packages needed by the initrd to check
15219 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15220 parameters. When @var{virtio?} is true, load additional modules so that the
15221 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15223 When @var{volatile-root?} is true, the root file system is writable but any changes
15227 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15228 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15229 [#:virtio? #t] [#:extra-modules '()]
15230 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15231 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15232 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15233 also behaves as in @code{raw-initrd}.
15235 When @var{virtio?} is true, load additional modules so that the
15236 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15238 The initrd is automatically populated with all the kernel modules necessary
15239 for @var{file-systems} and for the given options. However, additional kernel
15240 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15241 loaded at boot time in the order in which they appear.
15244 Needless to say, the initrds we produce and use embed a
15245 statically-linked Guile, and the initialization program is a Guile
15246 program. That gives a lot of flexibility. The
15247 @code{expression->initrd} procedure builds such an initrd, given the
15248 program to run in that initrd.
15250 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15251 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15252 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15253 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15254 upon booting. All the derivations referenced by @var{exp} are
15255 automatically copied to the initrd.
15258 @node GRUB Configuration
15259 @subsection GRUB Configuration
15262 @cindex boot loader
15264 The operating system uses GNU@tie{}GRUB as its boot loader
15265 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
15266 configured using a @code{grub-configuration} declaration. This data type
15267 is exported by the @code{(gnu system grub)} module and described below.
15269 @deftp {Data Type} grub-configuration
15270 The type of a GRUB configuration declaration.
15274 @item @code{device}
15275 This is a string denoting the boot device. It must be a device name
15276 understood by the @command{grub-install} command, such as
15277 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
15280 @item @code{menu-entries} (default: @code{()})
15281 A possibly empty list of @code{menu-entry} objects (see below), denoting
15282 entries to appear in the GRUB boot menu, in addition to the current
15283 system entry and the entry pointing to previous system generations.
15285 @item @code{default-entry} (default: @code{0})
15286 The index of the default boot menu entry. Index 0 is for the entry of the
15289 @item @code{timeout} (default: @code{5})
15290 The number of seconds to wait for keyboard input before booting. Set to
15291 0 to boot immediately, and to -1 to wait indefinitely.
15293 @item @code{theme} (default: @var{%default-theme})
15294 The @code{grub-theme} object describing the theme to use.
15296 @item @code{grub} (default: @code{grub})
15297 @cindex EFI, bootloader
15298 @cindex UEFI, bootloader
15299 @cindex BIOS, bootloader
15300 The GRUB package to use. Currently either @code{grub}, for ``legacy''
15301 x86 BIOS systems, or @code{grub-efi}, for modern systems using the
15302 @dfn{Unified Extensible Firmware Interface} (UEFI).
15304 @item @code{terminal-outputs} (default: @code{'gfxterm})
15305 The output terminals used for the GRUB boot menu, as a list of symbols.
15306 These values are accepted: @code{console}, @code{serial},
15307 @code{serial_@{0-3@}}, @code{gfxterm}, @code{vga_text}, @code{mda_text},
15308 @code{morse}, and @code{pkmodem}. This field corresponds to the GRUB
15309 variable GRUB_TERMINAL_OUTPUT (@pxref{Simple configuration,,, grub,GNU
15312 @item @code{terminal-inputs} (default: @code{'()})
15313 The input terminals used for the GRUB boot menu, as a list of symbols.
15314 The default is the native platform terminal as determined by GRUB at
15315 run-time. These values are accepted: @code{console}, @code{serial},
15316 @code{serial_@{0-3@}}, @code{at_keyboard}, and @code{usb_keyboard}.
15317 This field corresponds to the GRUB variable GRUB_TERMINAL_INPUT
15318 (@pxref{Simple configuration,,, grub,GNU GRUB manual}).
15320 @item @code{serial-unit} (default: @code{#f})
15321 The serial unit used by GRUB, as an integer from 0 to 3. The default
15322 value is chosen by GRUB at run-time; currently GRUB chooses 0, which
15323 corresponds to COM1 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15325 @item @code{serial-speed} (default: @code{#f})
15326 The speed of the serial interface, as an integer. The default value is
15327 chosen by GRUB at run-time; currently GRUB chooses 9600@tie{}bps
15328 (@pxref{Serial terminal,,, grub,GNU GRUB manual}).
15335 Should you want to list additional boot menu entries @i{via} the
15336 @code{menu-entries} field above, you will need to create them with the
15337 @code{menu-entry} form. For example, imagine you want to be able to
15338 boot another distro (hard to imagine!), you can define a menu entry
15343 (label "The Other Distro")
15344 (linux "/boot/old/vmlinux-2.6.32")
15345 (linux-arguments '("root=/dev/sda2"))
15346 (initrd "/boot/old/initrd"))
15351 @deftp {Data Type} menu-entry
15352 The type of an entry in the GRUB boot menu.
15357 The label to show in the menu---e.g., @code{"GNU"}.
15360 The Linux kernel image to boot, for example:
15363 (file-append linux-libre "/bzImage")
15366 It is also possible to specify a device explicitly in the file path
15367 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
15368 GNU GRUB manual}), for example:
15371 "(hd0,msdos1)/boot/vmlinuz"
15374 If the device is specified explicitly as above, then the @code{device}
15375 field is ignored entirely.
15377 @item @code{linux-arguments} (default: @code{()})
15378 The list of extra Linux kernel command-line arguments---e.g.,
15379 @code{("console=ttyS0")}.
15381 @item @code{initrd}
15382 A G-Expression or string denoting the file name of the initial RAM disk
15383 to use (@pxref{G-Expressions}).
15385 @item @code{device} (default: @code{#f})
15386 The device where the kernel and initrd are to be found---i.e., the GRUB
15387 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15389 This may be a file system label (a string), a file system UUID (a
15390 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
15391 search the device containing the file specified by the @code{linux}
15392 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
15393 an OS device name such as @file{/dev/sda1}.
15395 @item @code{device-mount-point} (default: @code{"/"})
15396 The mount point of the above device on the system. You probably do not
15397 need to change the default value. GuixSD uses it to strip the prefix of
15398 store file names for systems where @file{/gnu} or @file{/gnu/store} is
15399 on a separate partition.
15404 @c FIXME: Write documentation once it's stable.
15405 Themes are created using the @code{grub-theme} form, which is not
15408 @defvr {Scheme Variable} %default-theme
15409 This is the default GRUB theme used by the operating system, with a
15410 fancy background image displaying the GNU and Guix logos.
15414 @node Invoking guix system
15415 @subsection Invoking @code{guix system}
15417 Once you have written an operating system declaration as seen in the
15418 previous section, it can be @dfn{instantiated} using the @command{guix
15419 system} command. The synopsis is:
15422 guix system @var{options}@dots{} @var{action} @var{file}
15425 @var{file} must be the name of a file containing an
15426 @code{operating-system} declaration. @var{action} specifies how the
15427 operating system is instantiated. Currently the following values are
15432 Build the operating system described in @var{file}, activate it, and
15433 switch to it@footnote{This action (and the related actions
15434 @code{switch-generation} and @code{roll-back}) are usable only on
15435 systems already running GuixSD.}.
15437 This effects all the configuration specified in @var{file}: user
15438 accounts, system services, global package list, setuid programs, etc.
15439 The command starts system services specified in @var{file} that are not
15440 currently running; if a service is currently running, it does not
15441 attempt to upgrade it since this would not be possible without stopping it
15444 This command creates a new generation whose number is one greater than
15445 the current generation (as reported by @command{guix system
15446 list-generations}). If that generation already exists, it will be
15447 overwritten. This behavior mirrors that of @command{guix package}
15448 (@pxref{Invoking guix package}).
15450 It also adds a GRUB menu entry for the new OS configuration, and moves
15451 entries for older configurations to a submenu---unless
15452 @option{--no-bootloader} is passed.
15455 @c The paragraph below refers to the problem discussed at
15456 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15457 It is highly recommended to run @command{guix pull} once before you run
15458 @command{guix system reconfigure} for the first time (@pxref{Invoking
15459 guix pull}). Failing to do that you would see an older version of Guix
15460 once @command{reconfigure} has completed.
15463 @item switch-generation
15464 @cindex generations
15465 Switch to an existing system generation. This action atomically
15466 switches the system profile to the specified system generation. It also
15467 rearranges the system's existing GRUB menu entries. It makes the menu
15468 entry for the specified system generation the default, and it moves the
15469 entries for the other generations to a submenu. The next time the
15470 system boots, it will use the specified system generation.
15472 The target generation can be specified explicitly by its generation
15473 number. For example, the following invocation would switch to system
15477 guix system switch-generation 7
15480 The target generation can also be specified relative to the current
15481 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15482 ``3 generations ahead of the current generation,'' and @code{-1} means
15483 ``1 generation prior to the current generation.'' When specifying a
15484 negative value such as @code{-1}, you must precede it with @code{--} to
15485 prevent it from being parsed as an option. For example:
15488 guix system switch-generation -- -1
15491 Currently, the effect of invoking this action is @emph{only} to switch
15492 the system profile to an existing generation and rearrange the GRUB menu
15493 entries. To actually start using the target system generation, you must
15494 reboot after running this action. In the future, it will be updated to
15495 do the same things as @command{reconfigure}, like activating and
15496 deactivating services.
15498 This action will fail if the specified generation does not exist.
15501 @cindex rolling back
15502 Switch to the preceding system generation. The next time the system
15503 boots, it will use the preceding system generation. This is the inverse
15504 of @command{reconfigure}, and it is exactly the same as invoking
15505 @command{switch-generation} with an argument of @code{-1}.
15507 Currently, as with @command{switch-generation}, you must reboot after
15508 running this action to actually start using the preceding system
15512 Build the derivation of the operating system, which includes all the
15513 configuration files and programs needed to boot and run the system.
15514 This action does not actually install anything.
15517 Populate the given directory with all the files necessary to run the
15518 operating system specified in @var{file}. This is useful for first-time
15519 installations of GuixSD. For instance:
15522 guix system init my-os-config.scm /mnt
15525 copies to @file{/mnt} all the store items required by the configuration
15526 specified in @file{my-os-config.scm}. This includes configuration
15527 files, packages, and so on. It also creates other essential files
15528 needed for the system to operate correctly---e.g., the @file{/etc},
15529 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
15531 This command also installs GRUB on the device specified in
15532 @file{my-os-config}, unless the @option{--no-bootloader} option was passed.
15535 @cindex virtual machine
15537 @anchor{guix system vm}
15538 Build a virtual machine that contains the operating system declared in
15539 @var{file}, and return a script to run that virtual machine (VM).
15540 Arguments given to the script are passed to QEMU.
15542 The VM shares its store with the host system.
15544 Additional file systems can be shared between the host and the VM using
15545 the @code{--share} and @code{--expose} command-line options: the former
15546 specifies a directory to be shared with write access, while the latter
15547 provides read-only access to the shared directory.
15549 The example below creates a VM in which the user's home directory is
15550 accessible read-only, and where the @file{/exchange} directory is a
15551 read-write mapping of @file{$HOME/tmp} on the host:
15554 guix system vm my-config.scm \
15555 --expose=$HOME --share=$HOME/tmp=/exchange
15558 On GNU/Linux, the default is to boot directly to the kernel; this has
15559 the advantage of requiring only a very tiny root disk image since the
15560 store of the host can then be mounted.
15562 The @code{--full-boot} option forces a complete boot sequence, starting
15563 with the bootloader. This requires more disk space since a root image
15564 containing at least the kernel, initrd, and bootloader data files must
15565 be created. The @code{--image-size} option can be used to specify the
15570 Return a virtual machine or disk image of the operating system declared
15571 in @var{file} that stands alone. Use the @option{--image-size} option
15572 to specify the size of the image.
15574 When using @code{vm-image}, the returned image is in qcow2 format, which
15575 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
15576 for more information on how to run the image in a virtual machine.
15578 When using @code{disk-image}, a raw disk image is produced; it can be
15579 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
15580 the device corresponding to a USB stick, one can copy the image to it
15581 using the following command:
15584 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
15588 Return a script to run the operating system declared in @var{file}
15589 within a container. Containers are a set of lightweight isolation
15590 mechanisms provided by the kernel Linux-libre. Containers are
15591 substantially less resource-demanding than full virtual machines since
15592 the kernel, shared objects, and other resources can be shared with the
15593 host system; this also means they provide thinner isolation.
15595 Currently, the script must be run as root in order to support more than
15596 a single user and group. The container shares its store with the host
15599 As with the @code{vm} action (@pxref{guix system vm}), additional file
15600 systems to be shared between the host and container can be specified
15601 using the @option{--share} and @option{--expose} options:
15604 guix system container my-config.scm \
15605 --expose=$HOME --share=$HOME/tmp=/exchange
15609 This option requires Linux-libre 3.19 or newer.
15614 @var{options} can contain any of the common build options (@pxref{Common
15615 Build Options}). In addition, @var{options} can contain one of the
15619 @item --system=@var{system}
15620 @itemx -s @var{system}
15621 Attempt to build for @var{system} instead of the host system type.
15622 This works as per @command{guix build} (@pxref{Invoking guix build}).
15626 Return the derivation file name of the given operating system without
15629 @item --image-size=@var{size}
15630 For the @code{vm-image} and @code{disk-image} actions, create an image
15631 of the given @var{size}. @var{size} may be a number of bytes, or it may
15632 include a unit as a suffix (@pxref{Block size, size specifications,,
15633 coreutils, GNU Coreutils}).
15635 @item --root=@var{file}
15636 @itemx -r @var{file}
15637 Make @var{file} a symlink to the result, and register it as a garbage
15640 @item --on-error=@var{strategy}
15641 Apply @var{strategy} when an error occurs when reading @var{file}.
15642 @var{strategy} may be one of the following:
15645 @item nothing-special
15646 Report the error concisely and exit. This is the default strategy.
15649 Likewise, but also display a backtrace.
15652 Report the error and enter Guile's debugger. From there, you can run
15653 commands such as @code{,bt} to get a backtrace, @code{,locals} to
15654 display local variable values, and more generally inspect the state of the
15655 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
15656 a list of available debugging commands.
15661 All the actions above, except @code{build} and @code{init},
15662 can use KVM support in the Linux-libre kernel. Specifically, if the
15663 machine has hardware virtualization support, the corresponding
15664 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
15665 must exist and be readable and writable by the user and by the
15666 build users of the daemon (@pxref{Build Environment Setup}).
15669 Once you have built, configured, re-configured, and re-re-configured
15670 your GuixSD installation, you may find it useful to list the operating
15671 system generations available on disk---and that you can choose from the
15676 @item list-generations
15677 List a summary of each generation of the operating system available on
15678 disk, in a human-readable way. This is similar to the
15679 @option{--list-generations} option of @command{guix package}
15680 (@pxref{Invoking guix package}).
15682 Optionally, one can specify a pattern, with the same syntax that is used
15683 in @command{guix package --list-generations}, to restrict the list of
15684 generations displayed. For instance, the following command displays
15685 generations that are up to 10 days old:
15688 $ guix system list-generations 10d
15693 The @command{guix system} command has even more to offer! The following
15694 sub-commands allow you to visualize how your system services relate to
15697 @anchor{system-extension-graph}
15700 @item extension-graph
15701 Emit in Dot/Graphviz format to standard output the @dfn{service
15702 extension graph} of the operating system defined in @var{file}
15703 (@pxref{Service Composition}, for more information on service
15709 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
15712 produces a PDF file showing the extension relations among services.
15714 @anchor{system-shepherd-graph}
15715 @item shepherd-graph
15716 Emit in Dot/Graphviz format to standard output the @dfn{dependency
15717 graph} of shepherd services of the operating system defined in
15718 @var{file}. @xref{Shepherd Services}, for more information and for an
15723 @node Running GuixSD in a VM
15724 @subsection Running GuixSD in a Virtual Machine
15726 @cindex virtual machine
15727 To run GuixSD in a virtual machine (VM), one can either use the
15728 pre-built GuixSD VM image distributed at
15729 @indicateurl{ftp://alpha.gnu.org/guix/guixsd-vm-image-@value{VERSION}.@var{system}.tar.xz}
15730 , or build their own virtual machine image using @command{guix system
15731 vm-image} (@pxref{Invoking guix system}). The returned image is in
15732 qcow2 format, which the @uref{http://qemu.org/, QEMU emulator} can
15736 If you built your own image, you must copy it out of the store
15737 (@pxref{The Store}) and give yourself permission to write to the copy
15738 before you can use it. When invoking QEMU, you must choose a system
15739 emulator that is suitable for your hardware platform. Here is a minimal
15740 QEMU invocation that will boot the result of @command{guix system
15741 vm-image} on x86_64 hardware:
15744 $ qemu-system-x86_64 \
15745 -net user -net nic,model=virtio \
15746 -enable-kvm -m 256 /tmp/qemu-image
15749 Here is what each of these options means:
15752 @item qemu-system-x86_64
15753 This specifies the hardware platform to emulate. This should match the
15757 Enable the unprivileged user-mode network stack. The guest OS can
15758 access the host but not vice versa. This is the simplest way to get the
15761 @item -net nic,model=virtio
15762 You must create a network interface of a given model. If you do not
15763 create a NIC, the boot will fail. Assuming your hardware platform is
15764 x86_64, you can get a list of available NIC models by running
15765 @command{qemu-system-x86_64 -net nic,model=help}.
15768 If your system has hardware virtualization extensions, enabling the
15769 virtual machine support (KVM) of the Linux kernel will make things run
15773 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
15774 which may be insufficient for some operations.
15776 @item /tmp/qemu-image
15777 The file name of the qcow2 image.
15780 The default @command{run-vm.sh} script that is returned by an invocation of
15781 @command{guix system vm} does not add a @command{-net user} flag by default.
15782 To get network access from within the vm add the @code{(dhcp-client-service)}
15783 to your system definition and start the VM using
15784 @command{`guix system vm config.scm` -net user}. An important caveat of using
15785 @command{-net user} for networking is that @command{ping} will not work, because
15786 it uses the ICMP protocol. You'll have to use a different command to check for
15787 network connectivity, for example @command{guix download}.
15789 @subsubsection Connecting Through SSH
15793 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
15794 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
15795 boot unsupervised. It requires you to type some characters to initialize the
15796 randomness generator. In addition you need to forward the SSH port, 22 by
15797 default, to the host. You can do this with
15800 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
15803 To connect to the VM you can run
15806 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
15809 The @command{-p} tells @command{ssh} the port you want to connect to.
15810 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
15811 every time you modify your @command{config.scm} file and the
15812 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
15813 connection to an unknown host every time you connect.
15815 @subsubsection Using @command{virt-viewer} with Spice
15817 As an alternative to the default @command{qemu} graphical client you can
15818 use the @command{remote-viewer} from the @command{virt-viewer} package. To
15819 connect pass the @command{-spice port=5930,disable-ticketing} flag to
15820 @command{qemu}. See previous section for further information on how to do this.
15822 Spice also allows you to do some nice stuff like share your clipboard with your
15823 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
15826 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
15827 -chardev spicevmc,name=vdagent,id=vdagent
15828 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
15829 name=com.redhat.spice.0
15832 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
15834 @node Defining Services
15835 @subsection Defining Services
15837 The previous sections show the available services and how one can combine
15838 them in an @code{operating-system} declaration. But how do we define
15839 them in the first place? And what is a service anyway?
15842 * Service Composition:: The model for composing services.
15843 * Service Types and Services:: Types and services.
15844 * Service Reference:: API reference.
15845 * Shepherd Services:: A particular type of service.
15848 @node Service Composition
15849 @subsubsection Service Composition
15853 Here we define a @dfn{service} as, broadly, something that extends the
15854 functionality of the operating system. Often a service is a process---a
15855 @dfn{daemon}---started when the system boots: a secure shell server, a
15856 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
15857 whose execution can be triggered by another daemon---e.g., an FTP server
15858 started by @command{inetd} or a D-Bus service activated by
15859 @command{dbus-daemon}. Occasionally, a service does not map to a
15860 daemon. For instance, the ``account'' service collects user accounts
15861 and makes sure they exist when the system runs; the ``udev'' service
15862 collects device management rules and makes them available to the eudev
15863 daemon; the @file{/etc} service populates the @file{/etc} directory
15866 @cindex service extensions
15867 GuixSD services are connected by @dfn{extensions}. For instance, the
15868 secure shell service @emph{extends} the Shepherd---the GuixSD
15869 initialization system, running as PID@tie{}1---by giving it the command
15870 lines to start and stop the secure shell daemon (@pxref{Networking
15871 Services, @code{lsh-service}}); the UPower service extends the D-Bus
15872 service by passing it its @file{.service} specification, and extends the
15873 udev service by passing it device management rules (@pxref{Desktop
15874 Services, @code{upower-service}}); the Guix daemon service extends the
15875 Shepherd by passing it the command lines to start and stop the daemon,
15876 and extends the account service by passing it a list of required build
15877 user accounts (@pxref{Base Services}).
15879 All in all, services and their ``extends'' relations form a directed
15880 acyclic graph (DAG). If we represent services as boxes and extensions
15881 as arrows, a typical system might provide something like this:
15883 @image{images/service-graph,,5in,Typical service extension graph.}
15885 @cindex system service
15886 At the bottom, we see the @dfn{system service}, which produces the
15887 directory containing everything to run and boot the system, as returned
15888 by the @command{guix system build} command. @xref{Service Reference},
15889 to learn about the other service types shown here.
15890 @xref{system-extension-graph, the @command{guix system extension-graph}
15891 command}, for information on how to generate this representation for a
15892 particular operating system definition.
15894 @cindex service types
15895 Technically, developers can define @dfn{service types} to express these
15896 relations. There can be any number of services of a given type on the
15897 system---for instance, a system running two instances of the GNU secure
15898 shell server (lsh) has two instances of @var{lsh-service-type}, with
15899 different parameters.
15901 The following section describes the programming interface for service
15902 types and services.
15904 @node Service Types and Services
15905 @subsubsection Service Types and Services
15907 A @dfn{service type} is a node in the DAG described above. Let us start
15908 with a simple example, the service type for the Guix build daemon
15909 (@pxref{Invoking guix-daemon}):
15912 (define guix-service-type
15916 (list (service-extension shepherd-root-service-type guix-shepherd-service)
15917 (service-extension account-service-type guix-accounts)
15918 (service-extension activation-service-type guix-activation)))
15919 (default-value (guix-configuration))))
15923 It defines three things:
15927 A name, whose sole purpose is to make inspection and debugging easier.
15930 A list of @dfn{service extensions}, where each extension designates the
15931 target service type and a procedure that, given the parameters of the
15932 service, returns a list of objects to extend the service of that type.
15934 Every service type has at least one service extension. The only
15935 exception is the @dfn{boot service type}, which is the ultimate service.
15938 Optionally, a default value for instances of this type.
15941 In this example, @var{guix-service-type} extends three services:
15944 @item shepherd-root-service-type
15945 The @var{guix-shepherd-service} procedure defines how the Shepherd
15946 service is extended. Namely, it returns a @code{<shepherd-service>}
15947 object that defines how @command{guix-daemon} is started and stopped
15948 (@pxref{Shepherd Services}).
15950 @item account-service-type
15951 This extension for this service is computed by @var{guix-accounts},
15952 which returns a list of @code{user-group} and @code{user-account}
15953 objects representing the build user accounts (@pxref{Invoking
15956 @item activation-service-type
15957 Here @var{guix-activation} is a procedure that returns a gexp, which is
15958 a code snippet to run at ``activation time''---e.g., when the service is
15962 A service of this type is instantiated like this:
15965 (service guix-service-type
15966 (guix-configuration
15968 (use-substitutes? #f)))
15971 The second argument to the @code{service} form is a value representing
15972 the parameters of this specific service instance.
15973 @xref{guix-configuration-type, @code{guix-configuration}}, for
15974 information about the @code{guix-configuration} data type. When the
15975 value is omitted, the default value specified by
15976 @code{guix-service-type} is used:
15979 (service guix-service-type)
15982 @var{guix-service-type} is quite simple because it extends other
15983 services but is not extensible itself.
15985 @c @subsubsubsection Extensible Service Types
15987 The service type for an @emph{extensible} service looks like this:
15990 (define udev-service-type
15991 (service-type (name 'udev)
15993 (list (service-extension shepherd-root-service-type
15994 udev-shepherd-service)))
15996 (compose concatenate) ;concatenate the list of rules
15997 (extend (lambda (config rules)
15999 (($ <udev-configuration> udev initial-rules)
16000 (udev-configuration
16001 (udev udev) ;the udev package to use
16002 (rules (append initial-rules rules)))))))))
16005 This is the service type for the
16006 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
16007 management daemon}. Compared to the previous example, in addition to an
16008 extension of @var{shepherd-root-service-type}, we see two new fields:
16012 This is the procedure to @dfn{compose} the list of extensions to
16013 services of this type.
16015 Services can extend the udev service by passing it lists of rules; we
16016 compose those extensions simply by concatenating them.
16019 This procedure defines how the value of the service is @dfn{extended} with
16020 the composition of the extensions.
16022 Udev extensions are composed into a list of rules, but the udev service
16023 value is itself a @code{<udev-configuration>} record. So here, we
16024 extend that record by appending the list of rules it contains to the
16025 list of contributed rules.
16028 There can be only one instance of an extensible service type such as
16029 @var{udev-service-type}. If there were more, the
16030 @code{service-extension} specifications would be ambiguous.
16032 Still here? The next section provides a reference of the programming
16033 interface for services.
16035 @node Service Reference
16036 @subsubsection Service Reference
16038 We have seen an overview of service types (@pxref{Service Types and
16039 Services}). This section provides a reference on how to manipulate
16040 services and service types. This interface is provided by the
16041 @code{(gnu services)} module.
16043 @deffn {Scheme Procedure} service @var{type} [@var{value}]
16044 Return a new service of @var{type}, a @code{<service-type>} object (see
16045 below.) @var{value} can be any object; it represents the parameters of
16046 this particular service instance.
16048 When @var{value} is omitted, the default value specified by @var{type}
16049 is used; if @var{type} does not specify a default value, an error is
16052 For instance, this:
16055 (service openssh-service-type)
16059 is equivalent to this:
16062 (service openssh-service-type
16063 (openssh-configuration))
16066 In both cases the result is an instance of @code{openssh-service-type}
16067 with the default configuration.
16070 @deffn {Scheme Procedure} service? @var{obj}
16071 Return true if @var{obj} is a service.
16074 @deffn {Scheme Procedure} service-kind @var{service}
16075 Return the type of @var{service}---i.e., a @code{<service-type>} object.
16078 @deffn {Scheme Procedure} service-value @var{service}
16079 Return the value associated with @var{service}. It represents its
16083 Here is an example of how a service is created and manipulated:
16087 (service nginx-service-type
16088 (nginx-configuration
16090 (log-directory log-directory)
16091 (run-directory run-directory)
16092 (file config-file))))
16097 (eq? (service-kind s) nginx-service-type)
16101 The @code{modify-services} form provides a handy way to change the
16102 parameters of some of the services of a list such as
16103 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
16104 evaluates to a list of services. Of course, you could always use
16105 standard list combinators such as @code{map} and @code{fold} to do that
16106 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
16107 @code{modify-services} simply provides a more concise form for this
16110 @deffn {Scheme Syntax} modify-services @var{services} @
16111 (@var{type} @var{variable} => @var{body}) @dots{}
16113 Modify the services listed in @var{services} according to the given
16114 clauses. Each clause has the form:
16117 (@var{type} @var{variable} => @var{body})
16120 where @var{type} is a service type---e.g.,
16121 @code{guix-service-type}---and @var{variable} is an identifier that is
16122 bound within the @var{body} to the service parameters---e.g., a
16123 @code{guix-configuration} instance---of the original service of that
16126 The @var{body} should evaluate to the new service parameters, which will
16127 be used to configure the new service. This new service will replace the
16128 original in the resulting list. Because a service's service parameters
16129 are created using @code{define-record-type*}, you can write a succinct
16130 @var{body} that evaluates to the new service parameters by using the
16131 @code{inherit} feature that @code{define-record-type*} provides.
16133 @xref{Using the Configuration System}, for example usage.
16137 Next comes the programming interface for service types. This is
16138 something you want to know when writing new service definitions, but not
16139 necessarily when simply looking for ways to customize your
16140 @code{operating-system} declaration.
16142 @deftp {Data Type} service-type
16143 @cindex service type
16144 This is the representation of a @dfn{service type} (@pxref{Service Types
16149 This is a symbol, used only to simplify inspection and debugging.
16151 @item @code{extensions}
16152 A non-empty list of @code{<service-extension>} objects (see below).
16154 @item @code{compose} (default: @code{#f})
16155 If this is @code{#f}, then the service type denotes services that cannot
16156 be extended---i.e., services that do not receive ``values'' from other
16159 Otherwise, it must be a one-argument procedure. The procedure is called
16160 by @code{fold-services} and is passed a list of values collected from
16161 extensions. It must return a value that is a valid parameter value for
16162 the service instance.
16164 @item @code{extend} (default: @code{#f})
16165 If this is @code{#f}, services of this type cannot be extended.
16167 Otherwise, it must be a two-argument procedure: @code{fold-services}
16168 calls it, passing it the initial value of the service as the first argument
16169 and the result of applying @code{compose} to the extension values as the
16173 @xref{Service Types and Services}, for examples.
16176 @deffn {Scheme Procedure} service-extension @var{target-type} @
16178 Return a new extension for services of type @var{target-type}.
16179 @var{compute} must be a one-argument procedure: @code{fold-services}
16180 calls it, passing it the value associated with the service that provides
16181 the extension; it must return a valid value for the target service.
16184 @deffn {Scheme Procedure} service-extension? @var{obj}
16185 Return true if @var{obj} is a service extension.
16188 Occasionally, you might want to simply extend an existing service. This
16189 involves creating a new service type and specifying the extension of
16190 interest, which can be verbose; the @code{simple-service} procedure
16191 provides a shorthand for this.
16193 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
16194 Return a service that extends @var{target} with @var{value}. This works
16195 by creating a singleton service type @var{name}, of which the returned
16196 service is an instance.
16198 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
16202 (simple-service 'my-mcron-job mcron-service-type
16203 #~(job '(next-hour (3)) "guix gc -F 2G"))
16207 At the core of the service abstraction lies the @code{fold-services}
16208 procedure, which is responsible for ``compiling'' a list of services
16209 down to a single directory that contains everything needed to boot and
16210 run the system---the directory shown by the @command{guix system build}
16211 command (@pxref{Invoking guix system}). In essence, it propagates
16212 service extensions down the service graph, updating each node parameters
16213 on the way, until it reaches the root node.
16215 @deffn {Scheme Procedure} fold-services @var{services} @
16216 [#:target-type @var{system-service-type}]
16217 Fold @var{services} by propagating their extensions down to the root of
16218 type @var{target-type}; return the root service adjusted accordingly.
16221 Lastly, the @code{(gnu services)} module also defines several essential
16222 service types, some of which are listed below.
16224 @defvr {Scheme Variable} system-service-type
16225 This is the root of the service graph. It produces the system directory
16226 as returned by the @command{guix system build} command.
16229 @defvr {Scheme Variable} boot-service-type
16230 The type of the ``boot service'', which produces the @dfn{boot script}.
16231 The boot script is what the initial RAM disk runs when booting.
16234 @defvr {Scheme Variable} etc-service-type
16235 The type of the @file{/etc} service. This service can be extended by
16236 passing it name/file tuples such as:
16239 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16242 In this example, the effect would be to add an @file{/etc/issue} file
16243 pointing to the given file.
16246 @defvr {Scheme Variable} setuid-program-service-type
16247 Type for the ``setuid-program service''. This service collects lists of
16248 executable file names, passed as gexps, and adds them to the set of
16249 setuid-root programs on the system (@pxref{Setuid Programs}).
16252 @defvr {Scheme Variable} profile-service-type
16253 Type of the service that populates the @dfn{system profile}---i.e., the
16254 programs under @file{/run/current-system/profile}. Other services can
16255 extend it by passing it lists of packages to add to the system profile.
16259 @node Shepherd Services
16260 @subsubsection Shepherd Services
16262 @cindex shepherd services
16264 @cindex init system
16265 The @code{(gnu services shepherd)} module provides a way to define
16266 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16267 initialization system---the first process that is started when the
16268 system boots, also known as PID@tie{}1
16269 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16271 Services in the Shepherd can depend on each other. For instance, the
16272 SSH daemon may need to be started after the syslog daemon has been
16273 started, which in turn can only happen once all the file systems have
16274 been mounted. The simple operating system defined earlier (@pxref{Using
16275 the Configuration System}) results in a service graph like this:
16277 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16279 You can actually generate such a graph for any operating system
16280 definition using the @command{guix system shepherd-graph} command
16281 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16283 The @var{%shepherd-root-service} is a service object representing
16284 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16285 by passing it lists of @code{<shepherd-service>} objects.
16287 @deftp {Data Type} shepherd-service
16288 The data type representing a service managed by the Shepherd.
16291 @item @code{provision}
16292 This is a list of symbols denoting what the service provides.
16294 These are the names that may be passed to @command{herd start},
16295 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16296 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16297 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16299 @item @code{requirements} (default: @code{'()})
16300 List of symbols denoting the Shepherd services this one depends on.
16302 @item @code{respawn?} (default: @code{#t})
16303 Whether to restart the service when it stops, for instance when the
16304 underlying process dies.
16307 @itemx @code{stop} (default: @code{#~(const #f)})
16308 The @code{start} and @code{stop} fields refer to the Shepherd's
16309 facilities to start and stop processes (@pxref{Service De- and
16310 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16311 G-expressions that get expanded in the Shepherd configuration file
16312 (@pxref{G-Expressions}).
16314 @item @code{documentation}
16315 A documentation string, as shown when running:
16318 herd doc @var{service-name}
16321 where @var{service-name} is one of the symbols in @var{provision}
16322 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16324 @item @code{modules} (default: @var{%default-modules})
16325 This is the list of modules that must be in scope when @code{start} and
16326 @code{stop} are evaluated.
16331 @defvr {Scheme Variable} shepherd-root-service-type
16332 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16334 This is the service type that extensions target when they want to create
16335 shepherd services (@pxref{Service Types and Services}, for an example).
16336 Each extension must pass a list of @code{<shepherd-service>}.
16339 @defvr {Scheme Variable} %shepherd-root-service
16340 This service represents PID@tie{}1.
16344 @node Documentation
16345 @section Documentation
16347 @cindex documentation, searching for
16348 @cindex searching for documentation
16349 @cindex Info, documentation format
16351 @cindex manual pages
16352 In most cases packages installed with Guix come with documentation.
16353 There are two main documentation formats: ``Info'', a browseable
16354 hypertext format used for GNU software, and ``manual pages'' (or ``man
16355 pages''), the linear documentation format traditionally found on Unix.
16356 Info manuals are accessed with the @command{info} command or with Emacs,
16357 and man pages are accessed using @command{man}.
16359 You can look for documentation of software installed on your system by
16360 keyword. For example, the following command searches for information
16361 about ``TLS'' in Info manuals:
16365 "(emacs)Network Security" -- STARTTLS
16366 "(emacs)Network Security" -- TLS
16367 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16368 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16373 The command below searches for the same keyword in man pages:
16377 SSL (7) - OpenSSL SSL/TLS library
16378 certtool (1) - GnuTLS certificate tool
16382 These searches are purely local to your computer so you have the
16383 guarantee that documentation you find corresponds to what you have
16384 actually installed, you can access it off-line, and your privacy is
16387 Once you have these results, you can view the relevant documentation by
16391 $ info "(gnutls)Core TLS API"
16401 Info manuals contain sections and indices as well as hyperlinks like
16402 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16403 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16404 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16405 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16406 Introduction}, for an introduction to Info navigation.
16408 @node Installing Debugging Files
16409 @section Installing Debugging Files
16411 @cindex debugging files
16412 Program binaries, as produced by the GCC compilers for instance, are
16413 typically written in the ELF format, with a section containing
16414 @dfn{debugging information}. Debugging information is what allows the
16415 debugger, GDB, to map binary code to source code; it is required to
16416 debug a compiled program in good conditions.
16418 The problem with debugging information is that is takes up a fair amount
16419 of disk space. For example, debugging information for the GNU C Library
16420 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16421 debugging info of all the installed programs is usually not an option.
16422 Yet, space savings should not come at the cost of an impediment to
16423 debugging---especially in the GNU system, which should make it easier
16424 for users to exert their computing freedom (@pxref{GNU Distribution}).
16426 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16427 mechanism that allows users to get the best of both worlds: debugging
16428 information can be stripped from the binaries and stored in separate
16429 files. GDB is then able to load debugging information from those files,
16430 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16433 The GNU distribution takes advantage of this by storing debugging
16434 information in the @code{lib/debug} sub-directory of a separate package
16435 output unimaginatively called @code{debug} (@pxref{Packages with
16436 Multiple Outputs}). Users can choose to install the @code{debug} output
16437 of a package when they need it. For instance, the following command
16438 installs the debugging information for the GNU C Library and for GNU
16442 guix package -i glibc:debug guile:debug
16445 GDB must then be told to look for debug files in the user's profile, by
16446 setting the @code{debug-file-directory} variable (consider setting it
16447 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16451 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16454 From there on, GDB will pick up debugging information from the
16455 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16457 In addition, you will most likely want GDB to be able to show the source
16458 code being debugged. To do that, you will have to unpack the source
16459 code of the package of interest (obtained with @code{guix build
16460 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16461 directory using the @code{directory} command (@pxref{Source Path,
16462 @code{directory},, gdb, Debugging with GDB}).
16464 @c XXX: keep me up-to-date
16465 The @code{debug} output mechanism in Guix is implemented by the
16466 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16467 opt-in---debugging information is available only for the packages
16468 with definitions explicitly declaring a @code{debug} output. This may be
16469 changed to opt-out in the future if our build farm servers can handle
16470 the load. To check whether a package has a @code{debug} output, use
16471 @command{guix package --list-available} (@pxref{Invoking guix package}).
16474 @node Security Updates
16475 @section Security Updates
16477 @cindex security updates
16478 @cindex security vulnerabilities
16479 Occasionally, important security vulnerabilities are discovered in software
16480 packages and must be patched. Guix developers try hard to keep track of
16481 known vulnerabilities and to apply fixes as soon as possible in the
16482 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16483 containing only security updates.) The @command{guix lint} tool helps
16484 developers find out about vulnerable versions of software packages in the
16489 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16490 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
16491 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16495 @xref{Invoking guix lint}, for more information.
16498 As of version @value{VERSION}, the feature described below is considered
16502 Guix follows a functional
16503 package management discipline (@pxref{Introduction}), which implies
16504 that, when a package is changed, @emph{every package that depends on it}
16505 must be rebuilt. This can significantly slow down the deployment of
16506 fixes in core packages such as libc or Bash, since basically the whole
16507 distribution would need to be rebuilt. Using pre-built binaries helps
16508 (@pxref{Substitutes}), but deployment may still take more time than
16512 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16513 for fast deployment of critical updates without the costs associated
16514 with a whole-distribution rebuild. The idea is to rebuild only the
16515 package that needs to be patched, and then to ``graft'' it onto packages
16516 explicitly installed by the user and that were previously referring to
16517 the original package. The cost of grafting is typically very low, and
16518 order of magnitudes lower than a full rebuild of the dependency chain.
16520 @cindex replacements of packages, for grafts
16521 For instance, suppose a security update needs to be applied to Bash.
16522 Guix developers will provide a package definition for the ``fixed''
16523 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16524 Packages}). Then, the original package definition is augmented with a
16525 @code{replacement} field pointing to the package containing the bug fix:
16532 (replacement bash-fixed)))
16535 From there on, any package depending directly or indirectly on Bash---as
16536 reported by @command{guix gc --requisites} (@pxref{Invoking guix
16537 gc})---that is installed is automatically ``rewritten'' to refer to
16538 @var{bash-fixed} instead of @var{bash}. This grafting process takes
16539 time proportional to the size of the package, usually less than a
16540 minute for an ``average'' package on a recent machine. Grafting is
16541 recursive: when an indirect dependency requires grafting, then grafting
16542 ``propagates'' up to the package that the user is installing.
16544 Currently, the length of the name and version of the graft and that of
16545 the package it replaces (@var{bash-fixed} and @var{bash} in the example
16546 above) must be equal. This restriction mostly comes from the fact that
16547 grafting works by patching files, including binary files, directly.
16548 Other restrictions may apply: for instance, when adding a graft to a
16549 package providing a shared library, the original shared library and its
16550 replacement must have the same @code{SONAME} and be binary-compatible.
16552 The @option{--no-grafts} command-line option allows you to forcefully
16553 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
16557 guix build bash --no-grafts
16561 returns the store file name of the original Bash, whereas:
16568 returns the store file name of the ``fixed'', replacement Bash. This
16569 allows you to distinguish between the two variants of Bash.
16571 To verify which Bash your whole profile refers to, you can run
16572 (@pxref{Invoking guix gc}):
16575 guix gc -R `readlink -f ~/.guix-profile` | grep bash
16579 @dots{} and compare the store file names that you get with those above.
16580 Likewise for a complete GuixSD system generation:
16583 guix gc -R `guix system build my-config.scm` | grep bash
16586 Lastly, to check which Bash running processes are using, you can use the
16587 @command{lsof} command:
16590 lsof | grep /gnu/store/.*bash
16594 @node Package Modules
16595 @section Package Modules
16597 From a programming viewpoint, the package definitions of the
16598 GNU distribution are provided by Guile modules in the @code{(gnu packages
16599 @dots{})} name space@footnote{Note that packages under the @code{(gnu
16600 packages @dots{})} module name space are not necessarily ``GNU
16601 packages''. This module naming scheme follows the usual Guile module
16602 naming convention: @code{gnu} means that these modules are distributed
16603 as part of the GNU system, and @code{packages} identifies modules that
16604 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
16605 Reference Manual}). For instance, the @code{(gnu packages emacs)}
16606 module exports a variable named @code{emacs}, which is bound to a
16607 @code{<package>} object (@pxref{Defining Packages}).
16609 The @code{(gnu packages @dots{})} module name space is
16610 automatically scanned for packages by the command-line tools. For
16611 instance, when running @code{guix package -i emacs}, all the @code{(gnu
16612 packages @dots{})} modules are scanned until one that exports a package
16613 object whose name is @code{emacs} is found. This package search
16614 facility is implemented in the @code{(gnu packages)} module.
16616 @cindex customization, of packages
16617 @cindex package module search path
16618 Users can store package definitions in modules with different
16619 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
16620 name and module name must match. For instance, the @code{(my-packages
16621 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
16622 relative to the load path specified with @option{--load-path} or
16623 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
16624 guile, GNU Guile Reference Manual}, for details.}. These package definitions
16625 will not be visible by default. Users can invoke commands such as
16626 @command{guix package} and @command{guix build} with the
16627 @code{-e} option so that they know where to find the package. Better
16628 yet, they can use the
16629 @code{-L} option of these commands to make those modules visible
16630 (@pxref{Invoking guix build, @code{--load-path}}), or define the
16631 @code{GUIX_PACKAGE_PATH} environment variable. This environment
16632 variable makes it easy to extend or customize the distribution and is
16633 honored by all the user interfaces.
16635 @defvr {Environment Variable} GUIX_PACKAGE_PATH
16636 This is a colon-separated list of directories to search for additional
16637 package modules. Directories listed in this variable take precedence
16638 over the own modules of the distribution.
16641 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
16642 each package is built based solely on other packages in the
16643 distribution. The root of this dependency graph is a small set of
16644 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
16645 bootstrap)} module. For more information on bootstrapping,
16646 @pxref{Bootstrapping}.
16648 @node Packaging Guidelines
16649 @section Packaging Guidelines
16651 @cindex packages, creating
16652 The GNU distribution is nascent and may well lack some of your favorite
16653 packages. This section describes how you can help make the distribution
16654 grow. @xref{Contributing}, for additional information on how you can
16657 Free software packages are usually distributed in the form of
16658 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
16659 all the source files. Adding a package to the distribution means
16660 essentially two things: adding a @dfn{recipe} that describes how to
16661 build the package, including a list of other packages required to build
16662 it, and adding @dfn{package metadata} along with that recipe, such as a
16663 description and licensing information.
16665 In Guix all this information is embodied in @dfn{package definitions}.
16666 Package definitions provide a high-level view of the package. They are
16667 written using the syntax of the Scheme programming language; in fact,
16668 for each package we define a variable bound to the package definition,
16669 and export that variable from a module (@pxref{Package Modules}).
16670 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
16671 creating packages. For more information on package definitions,
16672 @pxref{Defining Packages}.
16674 Once a package definition is in place, stored in a file in the Guix
16675 source tree, it can be tested using the @command{guix build} command
16676 (@pxref{Invoking guix build}). For example, assuming the new package is
16677 called @code{gnew}, you may run this command from the Guix build tree
16678 (@pxref{Running Guix Before It Is Installed}):
16681 ./pre-inst-env guix build gnew --keep-failed
16684 Using @code{--keep-failed} makes it easier to debug build failures since
16685 it provides access to the failed build tree. Another useful
16686 command-line option when debugging is @code{--log-file}, to access the
16689 If the package is unknown to the @command{guix} command, it may be that
16690 the source file contains a syntax error, or lacks a @code{define-public}
16691 clause to export the package variable. To figure it out, you may load
16692 the module from Guile to get more information about the actual error:
16695 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
16698 Once your package builds correctly, please send us a patch
16699 (@pxref{Contributing}). Well, if you need help, we will be happy to
16700 help you too. Once the patch is committed in the Guix repository, the
16701 new package automatically gets built on the supported platforms by
16702 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
16705 @cindex substituter
16706 Users can obtain the new package definition simply by running
16707 @command{guix pull} (@pxref{Invoking guix pull}). When
16708 @code{hydra.gnu.org} is done building the package, installing the
16709 package automatically downloads binaries from there
16710 (@pxref{Substitutes}). The only place where human intervention is
16711 needed is to review and apply the patch.
16715 * Software Freedom:: What may go into the distribution.
16716 * Package Naming:: What's in a name?
16717 * Version Numbers:: When the name is not enough.
16718 * Synopses and Descriptions:: Helping users find the right package.
16719 * Python Modules:: A touch of British comedy.
16720 * Perl Modules:: Little pearls.
16721 * Java Packages:: Coffee break.
16722 * Fonts:: Fond of fonts.
16725 @node Software Freedom
16726 @subsection Software Freedom
16728 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
16729 @cindex free software
16730 The GNU operating system has been developed so that users can have
16731 freedom in their computing. GNU is @dfn{free software}, meaning that
16732 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
16733 essential freedoms}: to run the program, to study and change the program
16734 in source code form, to redistribute exact copies, and to distribute
16735 modified versions. Packages found in the GNU distribution provide only
16736 software that conveys these four freedoms.
16738 In addition, the GNU distribution follow the
16739 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
16740 software distribution guidelines}. Among other things, these guidelines
16741 reject non-free firmware, recommendations of non-free software, and
16742 discuss ways to deal with trademarks and patents.
16744 Some otherwise free upstream package sources contain a small and optional
16745 subset that violates the above guidelines, for instance because this subset
16746 is itself non-free code. When that happens, the offending items are removed
16747 with appropriate patches or code snippets in the @code{origin} form of the
16748 package (@pxref{Defining Packages}). This way, @code{guix
16749 build --source} returns the ``freed'' source rather than the unmodified
16753 @node Package Naming
16754 @subsection Package Naming
16756 @cindex package name
16757 A package has actually two names associated with it:
16758 First, there is the name of the @emph{Scheme variable}, the one following
16759 @code{define-public}. By this name, the package can be made known in the
16760 Scheme code, for instance as input to another package. Second, there is
16761 the string in the @code{name} field of a package definition. This name
16762 is used by package management commands such as
16763 @command{guix package} and @command{guix build}.
16765 Both are usually the same and correspond to the lowercase conversion of
16766 the project name chosen upstream, with underscores replaced with
16767 hyphens. For instance, GNUnet is available as @code{gnunet}, and
16768 SDL_net as @code{sdl-net}.
16770 We do not add @code{lib} prefixes for library packages, unless these are
16771 already part of the official project name. But @pxref{Python
16772 Modules} and @ref{Perl Modules} for special rules concerning modules for
16773 the Python and Perl languages.
16775 Font package names are handled differently, @pxref{Fonts}.
16778 @node Version Numbers
16779 @subsection Version Numbers
16781 @cindex package version
16782 We usually package only the latest version of a given free software
16783 project. But sometimes, for instance for incompatible library versions,
16784 two (or more) versions of the same package are needed. These require
16785 different Scheme variable names. We use the name as defined
16786 in @ref{Package Naming}
16787 for the most recent version; previous versions use the same name, suffixed
16788 by @code{-} and the smallest prefix of the version number that may
16789 distinguish the two versions.
16791 The name inside the package definition is the same for all versions of a
16792 package and does not contain any version number.
16794 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
16797 (define-public gtk+
16802 (define-public gtk+-2
16805 (version "2.24.20")
16808 If we also wanted GTK+ 3.8.2, this would be packaged as
16810 (define-public gtk+-3.8
16817 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
16818 @c for a discussion of what follows.
16819 @cindex version number, for VCS snapshots
16820 Occasionally, we package snapshots of upstream's version control system
16821 (VCS) instead of formal releases. This should remain exceptional,
16822 because it is up to upstream developers to clarify what the stable
16823 release is. Yet, it is sometimes necessary. So, what should we put in
16824 the @code{version} field?
16826 Clearly, we need to make the commit identifier of the VCS snapshot
16827 visible in the version string, but we also need to make sure that the
16828 version string is monotonically increasing so that @command{guix package
16829 --upgrade} can determine which version is newer. Since commit
16830 identifiers, notably with Git, are not monotonically increasing, we add
16831 a revision number that we increase each time we upgrade to a newer
16832 snapshot. The resulting version string looks like this:
16837 | | `-- upstream commit ID
16839 | `--- Guix package revision
16841 latest upstream version
16844 It is a good idea to strip commit identifiers in the @code{version}
16845 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
16846 aesthetics have a role to play here) as well as problems related to OS
16847 limits such as the maximum shebang length (127 bytes for the Linux
16848 kernel.) It is best to use the full commit identifiers in
16849 @code{origin}s, though, to avoid ambiguities. A typical package
16850 definition may look like this:
16854 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
16855 (revision "1")) ;Guix package revision
16857 (version (string-append "0.9-" revision "."
16858 (string-take commit 7)))
16861 (uri (git-reference
16862 (url "git://example.org/my-package.git")
16864 (sha256 (base32 "1mbikn@dots{}"))
16865 (file-name (string-append "my-package-" version
16871 @node Synopses and Descriptions
16872 @subsection Synopses and Descriptions
16874 @cindex package description
16875 @cindex package synopsis
16876 As we have seen before, each package in GNU@tie{}Guix includes a
16877 synopsis and a description (@pxref{Defining Packages}). Synopses and
16878 descriptions are important: They are what @command{guix package
16879 --search} searches, and a crucial piece of information to help users
16880 determine whether a given package suits their needs. Consequently,
16881 packagers should pay attention to what goes into them.
16883 Synopses must start with a capital letter and must not end with a
16884 period. They must not start with ``a'' or ``the'', which usually does
16885 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
16886 tool that frobs files''. The synopsis should say what the package
16887 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
16888 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
16889 matching a pattern''.
16891 Keep in mind that the synopsis must be meaningful for a very wide
16892 audience. For example, ``Manipulate alignments in the SAM format''
16893 might make sense for a seasoned bioinformatics researcher, but might be
16894 fairly unhelpful or even misleading to a non-specialized audience. It
16895 is a good idea to come up with a synopsis that gives an idea of the
16896 application domain of the package. In this example, this might give
16897 something like ``Manipulate nucleotide sequence alignments'', which
16898 hopefully gives the user a better idea of whether this is what they are
16901 Descriptions should take between five and ten lines. Use full
16902 sentences, and avoid using acronyms without first introducing them.
16903 Please avoid marketing phrases such as ``world-leading'',
16904 ``industrial-strength'', and ``next-generation'', and avoid superlatives
16905 like ``the most advanced''---they are not helpful to users looking for a
16906 package and may even sound suspicious. Instead, try to be factual,
16907 mentioning use cases and features.
16909 @cindex Texinfo markup, in package descriptions
16910 Descriptions can include Texinfo markup, which is useful to introduce
16911 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
16912 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
16913 should be careful when using some characters for example @samp{@@} and
16914 curly braces which are the basic special characters in Texinfo
16915 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
16916 such as @command{guix package --show} take care of rendering it
16919 Synopses and descriptions are translated by volunteers
16920 @uref{http://translationproject.org/domain/guix-packages.html, at the
16921 Translation Project} so that as many users as possible can read them in
16922 their native language. User interfaces search them and display them in
16923 the language specified by the current locale.
16925 Translation is a lot of work so, as a packager, please pay even more
16926 attention to your synopses and descriptions as every change may entail
16927 additional work for translators. In order to help them, it is possible
16928 to make recommendations or instructions visible to them by inserting
16929 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
16933 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
16934 (description "ARandR is designed to provide a simple visual front end
16935 for the X11 resize-and-rotate (RandR) extension. @dots{}")
16939 @node Python Modules
16940 @subsection Python Modules
16943 We currently package Python 2 and Python 3, under the Scheme variable names
16944 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
16945 To avoid confusion and naming clashes with other programming languages, it
16946 seems desirable that the name of a package for a Python module contains
16947 the word @code{python}.
16949 Some modules are compatible with only one version of Python, others with both.
16950 If the package Foo compiles only with Python 3, we name it
16951 @code{python-foo}; if it compiles only with Python 2, we name it
16952 @code{python2-foo}. If it is compatible with both versions, we create two
16953 packages with the corresponding names.
16955 If a project already contains the word @code{python}, we drop this;
16956 for instance, the module python-dateutil is packaged under the names
16957 @code{python-dateutil} and @code{python2-dateutil}. If the project name
16958 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
16961 @subsubsection Specifying Dependencies
16962 @cindex inputs, for Python packages
16964 Dependency information for Python packages is usually available in the
16965 package source tree, with varying degrees of accuracy: in the
16966 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
16968 Your mission, when writing a recipe for a Python package, is to map
16969 these dependencies to the appropriate type of ``input'' (@pxref{package
16970 Reference, inputs}). Although the @code{pypi} importer normally does a
16971 good job (@pxref{Invoking guix import}), you may want to check the
16972 following check list to determine which dependency goes where.
16977 We currently package Python 2 with @code{setuptools} and @code{pip}
16978 installed like Python 3.4 has per default. Thus you don't need to
16979 specify either of these as an input. @command{guix lint} will warn you
16983 Python dependencies required at run time go into
16984 @code{propagated-inputs}. They are typically defined with the
16985 @code{install_requires} keyword in @file{setup.py}, or in the
16986 @file{requirements.txt} file.
16989 Python packages required only at build time---e.g., those listed with
16990 the @code{setup_requires} keyword in @file{setup.py}---or only for
16991 testing---e.g., those in @code{tests_require}---go into
16992 @code{native-inputs}. The rationale is that (1) they do not need to be
16993 propagated because they are not needed at run time, and (2) in a
16994 cross-compilation context, it's the ``native'' input that we'd want.
16996 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
16997 frameworks. Of course if any of these packages is also required at
16998 run-time, it needs to go to @code{propagated-inputs}.
17001 Anything that does not fall in the previous categories goes to
17002 @code{inputs}, for example programs or C libraries required for building
17003 Python packages containing C extensions.
17006 If a Python package has optional dependencies (@code{extras_require}),
17007 it is up to you to decide whether to add them or not, based on their
17008 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
17015 @subsection Perl Modules
17018 Perl programs standing for themselves are named as any other package,
17019 using the lowercase upstream name.
17020 For Perl packages containing a single class, we use the lowercase class name,
17021 replace all occurrences of @code{::} by dashes and prepend the prefix
17023 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
17024 Modules containing several classes keep their lowercase upstream name and
17025 are also prepended by @code{perl-}. Such modules tend to have the word
17026 @code{perl} somewhere in their name, which gets dropped in favor of the
17027 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
17030 @node Java Packages
17031 @subsection Java Packages
17034 Java programs standing for themselves are named as any other package,
17035 using the lowercase upstream name.
17037 To avoid confusion and naming clashes with other programming languages,
17038 it is desirable that the name of a package for a Java package is
17039 prefixed with @code{java-}. If a project already contains the word
17040 @code{java}, we drop this; for instance, the package @code{ngsjava} is
17041 packaged under the name @code{java-ngs}.
17043 For Java packages containing a single class or a small class hierarchy,
17044 we use the lowercase class name, replace all occurrences of @code{.} by
17045 dashes and prepend the prefix @code{java-}. So the class
17046 @code{apache.commons.cli} becomes package
17047 @code{java-apache-commons-cli}.
17054 For fonts that are in general not installed by a user for typesetting
17055 purposes, or that are distributed as part of a larger software package,
17056 we rely on the general packaging rules for software; for instance, this
17057 applies to the fonts delivered as part of the X.Org system or fonts that
17058 are part of TeX Live.
17060 To make it easier for a user to search for fonts, names for other packages
17061 containing only fonts are constructed as follows, independently of the
17062 upstream package name.
17064 The name of a package containing only one font family starts with
17065 @code{font-}; it is followed by the foundry name and a dash @code{-}
17066 if the foundry is known, and the font family name, in which spaces are
17067 replaced by dashes (and as usual, all upper case letters are transformed
17069 For example, the Gentium font family by SIL is packaged under the name
17070 @code{font-sil-gentium}.
17072 For a package containing several font families, the name of the collection
17073 is used in the place of the font family name.
17074 For instance, the Liberation fonts consist of three families,
17075 Liberation Sans, Liberation Serif and Liberation Mono.
17076 These could be packaged separately under the names
17077 @code{font-liberation-sans} and so on; but as they are distributed together
17078 under a common name, we prefer to package them together as
17079 @code{font-liberation}.
17081 In the case where several formats of the same font family or font collection
17082 are packaged separately, a short form of the format, prepended by a dash,
17083 is added to the package name. We use @code{-ttf} for TrueType fonts,
17084 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
17089 @node Bootstrapping
17090 @section Bootstrapping
17092 @c Adapted from the ELS 2013 paper.
17094 @cindex bootstrapping
17096 Bootstrapping in our context refers to how the distribution gets built
17097 ``from nothing''. Remember that the build environment of a derivation
17098 contains nothing but its declared inputs (@pxref{Introduction}). So
17099 there's an obvious chicken-and-egg problem: how does the first package
17100 get built? How does the first compiler get compiled? Note that this is
17101 a question of interest only to the curious hacker, not to the regular
17102 user, so you can shamelessly skip this section if you consider yourself
17103 a ``regular user''.
17105 @cindex bootstrap binaries
17106 The GNU system is primarily made of C code, with libc at its core. The
17107 GNU build system itself assumes the availability of a Bourne shell and
17108 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
17109 `grep'. Furthermore, build programs---programs that run
17110 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
17111 (@pxref{Derivations}). Consequently, to be able to build anything at
17112 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
17113 Binutils, libc, and the other packages mentioned above---the
17114 @dfn{bootstrap binaries}.
17116 These bootstrap binaries are ``taken for granted'', though we can also
17117 re-create them if needed (more on that later).
17119 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
17121 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
17122 @c large image, it's hard to scroll. Oh well.
17123 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
17125 The figure above shows the very beginning of the dependency graph of the
17126 distribution, corresponding to the package definitions of the @code{(gnu
17127 packages bootstrap)} module. A similar figure can be generated with
17128 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
17131 guix graph -t derivation \
17132 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
17136 At this level of detail, things are
17137 slightly complex. First, Guile itself consists of an ELF executable,
17138 along with many source and compiled Scheme files that are dynamically
17139 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
17140 tarball shown in this graph. This tarball is part of Guix's ``source''
17141 distribution, and gets inserted into the store with @code{add-to-store}
17142 (@pxref{The Store}).
17144 But how do we write a derivation that unpacks this tarball and adds it
17145 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
17146 derivation---the first one that gets built---uses @code{bash} as its
17147 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
17148 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
17149 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
17150 the Guix source distribution, whose sole purpose is to allow the Guile
17151 tarball to be unpacked.
17153 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
17154 Guile that can be used to run subsequent build programs. Its first task
17155 is to download tarballs containing the other pre-built binaries---this
17156 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
17157 @code{ftp-client.scm} are used for this purpose. The
17158 @code{module-import.drv} derivations import those modules in a directory
17159 in the store, using the original layout. The
17160 @code{module-import-compiled.drv} derivations compile those modules, and
17161 write them in an output directory with the right layout. This
17162 corresponds to the @code{#:modules} argument of
17163 @code{build-expression->derivation} (@pxref{Derivations}).
17165 Finally, the various tarballs are unpacked by the
17166 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
17167 etc., at which point we have a working C tool chain.
17170 @unnumberedsubsec Building the Build Tools
17172 Bootstrapping is complete when we have a full tool chain that does not
17173 depend on the pre-built bootstrap tools discussed above. This
17174 no-dependency requirement is verified by checking whether the files of
17175 the final tool chain contain references to the @file{/gnu/store}
17176 directories of the bootstrap inputs. The process that leads to this
17177 ``final'' tool chain is described by the package definitions found in
17178 the @code{(gnu packages commencement)} module.
17180 The @command{guix graph} command allows us to ``zoom out'' compared to
17181 the graph above, by looking at the level of package objects instead of
17182 individual derivations---remember that a package may translate to
17183 several derivations, typically one derivation to download its source,
17184 one to build the Guile modules it needs, and one to actually build the
17185 package from source. The command:
17188 guix graph -t bag \
17189 -e '(@@@@ (gnu packages commencement)
17190 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
17194 produces the dependency graph leading to the ``final'' C
17195 library@footnote{You may notice the @code{glibc-intermediate} label,
17196 suggesting that it is not @emph{quite} final, but as a good
17197 approximation, we will consider it final.}, depicted below.
17199 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
17201 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
17202 The first tool that gets built with the bootstrap binaries is
17203 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
17204 for all the following packages. From there Findutils and Diffutils get
17207 Then come the first-stage Binutils and GCC, built as pseudo cross
17208 tools---i.e., with @code{--target} equal to @code{--host}. They are
17209 used to build libc. Thanks to this cross-build trick, this libc is
17210 guaranteed not to hold any reference to the initial tool chain.
17212 From there the final Binutils and GCC (not shown above) are built.
17214 from the final Binutils, and links programs against the just-built libc.
17215 This tool chain is used to build the other packages used by Guix and by
17216 the GNU Build System: Guile, Bash, Coreutils, etc.
17218 And voilà! At this point we have the complete set of build tools that
17219 the GNU Build System expects. These are in the @code{%final-inputs}
17220 variable of the @code{(gnu packages commencement)} module, and are
17221 implicitly used by any package that uses @code{gnu-build-system}
17222 (@pxref{Build Systems, @code{gnu-build-system}}).
17225 @unnumberedsubsec Building the Bootstrap Binaries
17227 @cindex bootstrap binaries
17228 Because the final tool chain does not depend on the bootstrap binaries,
17229 those rarely need to be updated. Nevertheless, it is useful to have an
17230 automated way to produce them, should an update occur, and this is what
17231 the @code{(gnu packages make-bootstrap)} module provides.
17233 The following command builds the tarballs containing the bootstrap
17234 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17235 of Coreutils and other basic command-line tools):
17238 guix build bootstrap-tarballs
17241 The generated tarballs are those that should be referred to in the
17242 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17245 Still here? Then perhaps by now you've started to wonder: when do we
17246 reach a fixed point? That is an interesting question! The answer is
17247 unknown, but if you would like to investigate further (and have
17248 significant computational and storage resources to do so), then let us
17252 @section Porting to a New Platform
17254 As discussed above, the GNU distribution is self-contained, and
17255 self-containment is achieved by relying on pre-built ``bootstrap
17256 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17257 operating system kernel, CPU architecture, and application binary
17258 interface (ABI). Thus, to port the distribution to a platform that is
17259 not yet supported, one must build those bootstrap binaries, and update
17260 the @code{(gnu packages bootstrap)} module to use them on that platform.
17262 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17263 When everything goes well, and assuming the GNU tool chain supports the
17264 target platform, this can be as simple as running a command like this
17268 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17271 For this to work, the @code{glibc-dynamic-linker} procedure in
17272 @code{(gnu packages bootstrap)} must be augmented to return the right
17273 file name for libc's dynamic linker on that platform; likewise,
17274 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17275 taught about the new platform.
17277 Once these are built, the @code{(gnu packages bootstrap)} module needs
17278 to be updated to refer to these binaries on the target platform. That
17279 is, the hashes and URLs of the bootstrap tarballs for the new platform
17280 must be added alongside those of the currently supported platforms. The
17281 bootstrap Guile tarball is treated specially: it is expected to be
17282 available locally, and @file{gnu/local.mk} has rules do download it for
17283 the supported architectures; a rule for the new platform must be added
17286 In practice, there may be some complications. First, it may be that the
17287 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17288 above) is not recognized by all the GNU tools. Typically, glibc
17289 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17290 configure flag (see @code{gcc.scm} for examples of how to handle this).
17291 Second, some of the required packages could fail to build for that
17292 platform. Lastly, the generated binaries could be broken for some
17295 @c *********************************************************************
17296 @include contributing.texi
17298 @c *********************************************************************
17299 @node Acknowledgments
17300 @chapter Acknowledgments
17302 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17303 which was designed and
17304 implemented by Eelco Dolstra, with contributions from other people (see
17305 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17306 management, and promoted unprecedented features, such as transactional
17307 package upgrades and rollbacks, per-user profiles, and referentially
17308 transparent build processes. Without this work, Guix would not exist.
17310 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17311 an inspiration for Guix.
17313 GNU@tie{}Guix itself is a collective work with contributions from a
17314 number of people. See the @file{AUTHORS} file in Guix for more
17315 information on these fine people. The @file{THANKS} file lists people
17316 who have helped by reporting bugs, taking care of the infrastructure,
17317 providing artwork and themes, making suggestions, and more---thank you!
17320 @c *********************************************************************
17321 @node GNU Free Documentation License
17322 @appendix GNU Free Documentation License
17323 @cindex license, GNU Free Documentation License
17324 @include fdl-1.3.texi
17326 @c *********************************************************************
17327 @node Concept Index
17328 @unnumbered Concept Index
17331 @node Programming Index
17332 @unnumbered Programming Index
17333 @syncodeindex tp fn
17334 @syncodeindex vr fn
17339 @c Local Variables:
17340 @c ispell-local-dictionary: "american";