5.2 Build Systems

Each package definition specifies a build system and arguments for that build system (see Defining Packages). This build-system field represents the build procedure of the package, as well implicit dependencies of that build procedure.

Build systems are <build-system> objects. The interface to create and manipulate them is provided by the (guix build-system) module, and actual build systems are exported by specific modules.

Under the hood, build systems first compile package objects to bags. A bag is like a package, but with less ornamentation—in other words, a bag is a lower-level representation of a package, which includes all the inputs of that package, including some that were implicitly added by the build system. This intermediate representation is then compiled to a derivation (see Derivations).

Build systems accept an optional list of arguments. In package definitions, these are passed via the arguments field (see Defining Packages). They are typically keyword arguments (see keyword arguments in Guile in GNU Guile Reference Manual). The value of these arguments is usually evaluated in the build stratum—i.e., by a Guile process launched by the daemon (see Derivations).

The main build system is gnu-build-system, which implements the standard build procedure for GNU packages and many other packages. It is provided by the (guix build-system gnu) module.

Scheme Variable: gnu-build-system

gnu-build-system represents the GNU Build System, and variants thereof (see configuration and makefile conventions in GNU Coding Standards).

In a nutshell, packages using it configured, built, and installed with the usual ./configure && make && make check && make install command sequence. In practice, a few additional steps are often needed. All these steps are split up in separate phases, notably⁶:

unpack

Unpack the source tarball, and change the current directory to the extracted source tree. If the source is actually a directory, copy it to the build tree, and enter that directory.

patch-source-shebangs

Patch shebangs encountered in source files so they refer to the right store file names. For instance, this changes #!/bin/sh to #!/gnu/store/…-bash-4.3/bin/sh.

configure

Run the configure script with a number of default options, such as --prefix=/gnu/store/…, as well as the options specified by the #:configure-flags argument.

build

Run make with the list of flags specified with #:make-flags. If the #:parallel-builds? argument is true (the default), build with make -j.

check

Run make check, or some other target specified with #:test-target, unless #:tests? #f is passed. If the #:parallel-tests? argument is true (the default), run make check -j.

install

Run make install with the flags listed in #:make-flags.

patch-shebangs

Patch shebangs on the installed executable files.

strip

Strip debugging symbols from ELF files (unless #:strip-binaries? is false), copying them to the debug output when available (see Installing Debugging Files).

The build-side module (guix build gnu-build-system) defines %standard-phases as the default list of build phases. %standard-phases is a list of symbol/procedure pairs, where the procedure implements the actual phase.

The list of phases used for a particular package can be changed with the #:phases parameter. For instance, passing:

#:phases (alist-delete 'configure %standard-phases)

means that all the phases described above will be used, except the configure phase.

In addition, this build system ensures that the “standard” environment for GNU packages is available. This includes tools such as GCC, libc, Coreutils, Bash, Make, Diffutils, grep, and sed (see the (guix build-system gnu) module for a complete list.) We call these the implicit inputs of a package, because package definitions don’t have to mention them.

Other <build-system> objects are defined to support other conventions and tools used by free software packages. They inherit most of gnu-build-system, and differ mainly in the set of inputs implicitly added to the build process, and in the list of phases executed. Some of these build systems are listed below.

Scheme Variable: cmake-build-system

This variable is exported by (guix build-system cmake). It implements the build procedure for packages using the CMake build tool.

It automatically adds the cmake package to the set of inputs. Which package is used can be specified with the #:cmake parameter.

The #:configure-flags parameter is taken as a list of flags passed to the cmake command. The #:build-type parameter specifies in abstract terms the flags passed to the compiler; it defaults to "RelWithDebInfo" (short for “release mode with debugging information”), which roughly means that code is compiled with -O2 -g, as is the case for Autoconf-based packages by default.

Scheme Variable: glib-or-gtk-build-system

This variable is exported by (guix build-system glib-or-gtk). It is intended for use with packages making use of GLib or GTK+.

This build system adds the following two phases to the ones defined by gnu-build-system:

glib-or-gtk-wrap

The phase glib-or-gtk-wrap ensures that programs found under bin/ are able to find GLib’s “schemas” and GTK+ modules. This is achieved by wrapping the programs in launch scripts that appropriately set the XDG_DATA_DIRS and GTK_PATH environment variables.

It is possible to exclude specific package outputs from that wrapping process by listing their names in the #:glib-or-gtk-wrap-excluded-outputs parameter. This is useful when an output is known not to contain any GLib or GTK+ binaries, and where wrapping would gratuitously add a dependency of that output on GLib and GTK+.

glib-or-gtk-compile-schemas

The phase glib-or-gtk-compile-schemas makes sure that all GLib’s GSettings schemas are compiled. Compilation is performed by the glib-compile-schemas program. It is provided by the package glib:bin which is automatically imported by the build system. The glib package providing glib-compile-schemas can be specified with the #:glib parameter.

Both phases are executed after the install phase.

Scheme Variable: python-build-system

This variable is exported by (guix build-system python). It implements the more or less standard build procedure used by Python packages, which consists in running python setup.py build and then python setup.py install --prefix=/gnu/store/….

For packages that install stand-alone Python programs under bin/, it takes care of wrapping these programs so their PYTHONPATH environment variable points to all the Python libraries they depend on.

Which Python package is used can be specified with the #:python parameter.

Scheme Variable: perl-build-system

This variable is exported by (guix build-system perl). It implements the standard build procedure for Perl packages, which either consists in running perl Build.PL --prefix=/gnu/store/…, followed by Build and Build install; or in running perl Makefile.PL PREFIX=/gnu/store/…, followed by make and make install; depending on which of Build.PL or Makefile.PL is present in the package distribution. Preference is given to the former if both Build.PL and Makefile.PL exist in the package distribution. This preference can be reversed by specifying #t for the #:make-maker? parameter.

The initial perl Makefile.PL or perl Build.PL invocation passes flags specified by the #:make-maker-flags or #:module-build-flags parameter, respectively.

Which Perl package is used can be specified with #:perl.

Scheme Variable: r-build-system

This variable is exported by (guix build-system r). It implements the build procedure used by R packages, which essentially is little more than running R CMD INSTALL --library=/gnu/store/… in an environment where R_LIBS_SITE contains the paths to all R package inputs. Tests are run after installation using the R function tools::testInstalledPackage.

Scheme Variable: ruby-build-system

This variable is exported by (guix build-system ruby). It implements the RubyGems build procedure used by Ruby packages, which involves running gem build followed by gem install.

The source field of a package that uses this build system typically references a gem archive, since this is the format that Ruby developers use when releasing their software. The build system unpacks the gem archive, potentially patches the source, runs the test suite, repackages the gem, and installs it. Additionally, directories and tarballs may be referenced to allow building unreleased gems from Git or a traditional source release tarball.

Which Ruby package is used can be specified with the #:ruby parameter. A list of additional flags to be passed to the gem command can be specified with the #:gem-flags parameter.

Scheme Variable: waf-build-system

This variable is exported by (guix build-system waf). It implements a build procedure around the waf script. The common phases—configure, build, and install—are implemented by passing their names as arguments to the waf script.

The waf script is executed by the Python interpreter. Which Python package is used to run the script can be specified with the #:python parameter.

Scheme Variable: haskell-build-system

This variable is exported by (guix build-system haskell). It implements the Cabal build procedure used by Haskell packages, which involves running runhaskell Setup.hs configure --prefix=/gnu/store/… and runhaskell Setup.hs build. Instead of installing the package by running runhaskell Setup.hs install, to avoid trying to register libraries in the read-only compiler store directory, the build system uses runhaskell Setup.hs copy, followed by runhaskell Setup.hs register. In addition, the build system generates the package documentation by running runhaskell Setup.hs haddock, unless #:haddock? #f is passed. Optional Haddock parameters can be passed with the help of the #:haddock-flags parameter. If the file Setup.hs is not found, the build system looks for Setup.lhs instead.

Which Haskell compiler is used can be specified with the #:haskell parameter which defaults to ghc.

Scheme Variable: emacs-build-system

This variable is exported by (guix build-system emacs). It implements an installation procedure similar to the one of Emacs’ own packaging system (see Packages in The GNU Emacs Manual).

It first creates the package-autoloads.el file, then it byte compiles all Emacs Lisp files. Differently from the Emacs packaging system, the Info documentation files are moved to the standard documentation directory and the dir file is deleted. Each package is installed in its own directory under share/emacs/site-lisp/guix.d.

Lastly, for packages that do not need anything as sophisticated, a “trivial” build system is provided. It is trivial in the sense that it provides basically no support: it does not pull any implicit inputs, and does not have a notion of build phases.

Scheme Variable: trivial-build-system

This variable is exported by (guix build-system trivial).

This build system requires a #:builder argument. This argument must be a Scheme expression that builds the package’s output(s)—as with build-expression->derivation (see build-expression->derivation).