Subject: Re: [PATCH v3 01/14] build-system: Add mix-build-system.

From: Liliana Marie Prikler <[email-masked]>
Date: Thu, 16 Nov 2023 03:05:29 +0100

Am Mittwoch, dem 15.11.2023 um 23:51 +0100 schrieb Pierre-Henry
Fröhring:
> * guix/build-system/mix.scm,
> * guix/build/mix-build-system.scm: New modules.
> 
> Change-Id: I2cbf6c963a530e73420da0eb17ffaf92827451bf
> ---
>  guix/build-system/mix.scm       | 181 ++++++++++++++++++++++++++++
>  guix/build/mix-build-system.scm | 205
> ++++++++++++++++++++++++++++++++
>  2 files changed, 386 insertions(+)
>  create mode 100644 guix/build-system/mix.scm
>  create mode 100644 guix/build/mix-build-system.scm
> 
> diff --git a/guix/build-system/mix.scm b/guix/build-system/mix.scm
> new file mode 100644
> index 00000000..ae80679b
> --- /dev/null
> +++ b/guix/build-system/mix.scm
> @@ -0,0 +1,181 @@
> +;;; GNU Guix --- Functional package management for GNU
> +;;; Copyright © 2023 Pierre-Henry Fröhring
> <[email-masked]>
> +;;;
> +;;; This file is part of GNU Guix.
> +;;;
> +;;; GNU Guix is free software; you can redistribute it and/or modify
> it
> +;;; under the terms of the GNU General Public License as published
> by
> +;;; the Free Software Foundation; either version 3 of the License,
> or (at
> +;;; your option) any later version.
> +;;;
> +;;; GNU Guix is distributed in the hope that it will be useful, but
> +;;; WITHOUT ANY WARRANTY; without even the implied warranty of
> +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +;;; GNU General Public License for more details.
> +;;;
> +;;; You should have received a copy of the GNU General Public
> License
> +;;; along with GNU Guix.  If not, see
> <http://www.gnu.org/licenses/>.
> +
> +;; Commentary:
> +;;
> +;; Standard build procedure for Elixir packages using 'mix'.  This
> is
> +;; implemented as an extension of 'gnu-build-system'.
> +;;
> +;; Code:
> +
> +(define-module (guix build-system mix)
> +  #:use-module (guix build mix-build-system)
> +  #:use-module (guix build-system gnu)
> +  #:use-module (guix build-system)
> +  #:use-module (guix gexp)
> +  #:use-module (guix monads)
> +  #:use-module (guix packages)
> +  #:use-module (guix search-paths)
> +  #:use-module (guix store)
> +  #:use-module (guix utils)
> +  #:use-module (ice-9 match)
> +  #:use-module (srfi srfi-1)
> +  #:use-module (srfi srfi-26)
> +  #:export (mix-build-system hexpm-uri))
> +
> +;; Lazily resolve the bindings to avoid circular dependencies.
> +(define (default-glibc-utf8-locales)
> +  (let* ((base (resolve-interface '(gnu packages base))))
> +    (module-ref base 'glibc-utf8-locales)))
> +
> +(define (default-elixir-hex)
> +  (let ((elixir (resolve-interface '(gnu packages elixir))))
> +    (module-ref elixir 'elixir-hex)))
> +
> +(define (default-rebar3)
> +  (let ((erlang (resolve-interface '(gnu packages erlang))))
> +    (module-ref erlang 'rebar3)))
> +
> +(define (default-elixir)
> +  "Return the default Elixir package."
> +  (let ((elixir (resolve-interface '(gnu packages elixir))))
> +    (module-ref elixir 'elixir)))
> +
> +(define (hexpm-uri name version)
> +  "Return the URI where to fetch the sources of a Hex package NAME
> at VERSION.
> +NAME is the name of the package which should look like: elixir-pkg-
> name-X.Y.Z
> +See: https://github.com/hexpm/specifications/blob/main/endpoints.md"
> +  ((compose
> +    (cut string-append "https://repo.hex.pm/tarballs/" <> "-"
> version ".tar")
> +    (cut string-replace-substring <> "-" "_")
> +    strip-elixir-prefix)
> +   name))
> +
> +;; A number of environment variables specific to the Mix build
> system are
> +;; reflected here.  They are documented at
> +;;
> https://hexdocs.pm/mix/1.15.7/Mix.html#module-environment-variables. 
> Other
> +;; parameters located in mix.exs are defined at
> +;;
> https://hexdocs.pm/mix/1.15.7/Mix.Project.html#module-configuration
> +(define* (mix-build name
> +                    inputs
> +                    #:key
> +                    source
> +                    (tests? #t)
> +                    (mix-path #f) ;See MIX_PATH.
> +                    (mix-exs "mix.exs") ;See MIX_EXS.
> +                    (build-per-environment #t) ;See
> :build_per_environment.
> +                    (phases '%standard-phases)
> +                    (outputs '("out"))
> +                    (search-paths '())
> +                    (system (%current-system))
> +                    (guile #f)
> +                    (imported-modules `((guix build mix-build-
> system)
> +                                        ,@%gnu-build-system-
> modules))
> +                    (modules '((guix build mix-build-system)
> +                               (guix build utils))))
> +  "Build SOURCE using Elixir, and with INPUTS."
> +
> +  ;; Check the documentation of :build_per_environment here:
> +  ;;
> https://hexdocs.pm/mix/1.15.7/Mix.Project.html#module-configuration A
> nd
> +  ;; "Environments" here:
> +  ;; https://hexdocs.pm/mix/1.15.7/Mix.html#module-environments
> +  (define mix-environments
> +    (if build-per-environment
> +        `("prod" ,@(if tests? '("test") '()))
> +        '("shared")))
> +
> +  (define builder
> +    (with-imported-modules imported-modules
> +      #~(begin
> +
> +          (use-modules #$@(sexp->gexp modules))
> +
> +          #$(with-build-variables inputs outputs
> +              #~(mix-build #:name #$name
> +                           #:source #+source
> +                           #:system #$system
> +                           #:tests? #$tests?
> +                           #:mix-path #$mix-path
> +                           #:mix-exs #$mix-exs
> +                           #:mix-environments '#$mix-environments
> +                           #:build-per-environment #$build-per-
> environment
> +                           #:phases #$(if (pair? phases)
> +                                          (sexp->gexp phases)
> +                                          phases)
> +                           #:outputs %outputs
> +                           #:search-paths '#$(sexp->gexp
> +                                              (map
> +                                               search-path-
> specification->sexp
> +                                               search-paths))
> +                           #:inputs
> +                           %build-inputs)))))
> +
> +  (mlet %store-monad ((guile (package->derivation (or guile
> (default-guile))
> +                                                  system
> +                                                  #:graft? #f)))
> +    (gexp->derivation name
> +                      builder
> +                      #:system system
> +                      #:graft? #f       ;consistent with 'gnu-build'
> +                      #:target #f
> +                      #:guile-for-build guile)))
> +
> +(define* (lower name
> +                #:key
> +                (elixir (default-elixir))
> +                (elixir-hex (default-elixir-hex))
> +                (glibc-utf8-locales (default-glibc-utf8-locales))
> +                (inputs '())
> +                (native-inputs '())
> +                (propagated-inputs '())
> +                (rebar3 (default-rebar3))
> +                (tests? #t)
> +                outputs
> +                source
> +                system
> +                target
> +                #:allow-other-keys #:rest arguments)
> +  "Return a bag for NAME."
> +  (let ((private-keywords
> +         '(#:inputs #:native-inputs
> +           #:outputs #:system #:target
> +           #:elixir #:elixir-hex #:glibc-utf8-locales
> +           #:rebar3 #:erlang))
> +        (build-inputs
> +         `(,@(standard-packages)
> +           ("glibc-utf8-locales" ,glibc-utf8-locales)
> +           ("erlang" ,(lookup-package-input elixir "erlang"))
> +           ("rebar3" ,rebar3)
> +           ("elixir" ,elixir)
> +           ("elixir-hex" ,elixir-hex)
> +           ,@inputs
> +           ,@native-inputs)))
> +  (bag (name name)
> +       (system system)
> +       (build-inputs build-inputs)
> +       (host-inputs (if target inputs '()))
> +       (outputs outputs)
> +       (build mix-build)
> +       (arguments (strip-keyword-arguments private-keywords
> arguments)))))
> +
> +(define mix-build-system
> +  (build-system (name 'mix)
> +                (description "The standard Mix build system")
> +                (lower lower)))
> +
> +;;; mix.scm ends here
> diff --git a/guix/build/mix-build-system.scm b/guix/build/mix-build-
> system.scm
> new file mode 100644
> index 00000000..0a1fcb5c
> --- /dev/null
> +++ b/guix/build/mix-build-system.scm
> @@ -0,0 +1,205 @@
> +;;; GNU Guix --- Functional package management for GNU
> +;;; Copyright © 2023 Pierre-Henry Fröhring
> <[email-masked]>
> +;;;
> +;;; This file is part of GNU Guix.
> +;;;
> +;;; GNU Guix is free software; you can redistribute it and/or modify
> it
> +;;; under the terms of the GNU General Public License as published
> by
> +;;; the Free Software Foundation; either version 3 of the License,
> or (at
> +;;; your option) any later version.
> +;;;
> +;;; GNU Guix is distributed in the hope that it will be useful, but
> +;;; WITHOUT ANY WARRANTY; without even the implied warranty of
> +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +;;; GNU General Public License for more details.
> +;;;
> +;;; You should have received a copy of the GNU General Public
> License
> +;;; along with GNU Guix.  If not, see
> <http://www.gnu.org/licenses/>.
> +
> +;; Commentary:
> +;;
> +;; Code:
> +
> +(define-module (guix build mix-build-system)
> +  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
> +  #:use-module (guix build utils)
> +  #:use-module (ice-9 ftw)
> +  #:use-module (ice-9 match)
> +  #:use-module (ice-9 regex)
> +  #:use-module (ice-9 string-fun)
> +  #:use-module (srfi srfi-1)
> +  #:use-module (srfi srfi-26)
> +  #:export (mix-build
> +            strip-elixir-prefix
> +            %standard-phases))
> +
> +(define (elixir-version elixir)
> +  "Return an X.Y string where X and Y are respectively the major and
> minor version number of ELIXIR.
> +Example: /gnu/store/…-elixir-1.14.0 → 1.14"
> +  ((compose
> +    (cut string-join <> ".")
> +    (cut take <> 2)
> +    (cut string-split <> #\.)
> +    last)
> +   (string-split elixir #\-)))
I don't think we need to be overly cute here.  The let-binding version
from python-build-system is less surprising to the uninitiated reader.

See also strip-store-file-name and package-name->name+version.

> +(define (elixir-libdir elixir path)
> +  "Return the path where all libraries for a specified ELIXIR
> version are installed."
> +  (string-append path "/lib/elixir/" (elixir-version elixir)))
You probably want to swap path and elixir and perhaps also find a way
to implicitly parameterize the latter so as to make it optional. 
> +
> +(define (erlang-libdir path)
> +  "Return the path of the directory where libraries of an Erlang
> package are
> +installed in the store."
> +  (string-append path "/lib/erlang/lib"))
> +
> +(define (install-dir inputs outputs)
> +  "Return the path of the current output's Elixir library.
> +Example: /gnu/store/…/lib/elixir/1.14"
> +  (elixir-libdir (assoc-ref inputs "elixir")
> +                 (assoc-ref outputs "out")))
> +
> +(define (strip-prefix prefix name)
> +  "Return NAME without the prefix PREFIX."
> +  (if (string-prefix? prefix name)
> +      (string-drop name (string-length prefix))
> +      name))
You might want to consider 
  (define* (strip-prefix name #:optional (prefix "elixir-")
     …)

> +(define (mix-build-dir mix-env)
> +  "Return the directory where build artifacts are to be installed
> according to
> +en environment MIX-ENV in the current directory."
> +  (string-append "_build/" mix-env "/lib"))
> +
> +(define* (unpack #:key source mix-path #:allow-other-keys)
> +  "Unpack SOURCE in the working directory, and change directory
> within the
> +source.  When SOURCE is a directory, copy it in a sub-directory of
> the current
> +working directory."
> +  (let ((gnu-unpack (assoc-ref gnu:%standard-phases 'unpack)))
> +    (gnu-unpack #:source source)
> +    (when (file-exists? "contents.tar.gz")
> +      (invoke "tar" "xvf" "contents.tar.gz"))))
> +
> +(define (list-directories dir)
> +  "List absolute paths of directories directly under the directory
> DIR."
> +  (map (cut string-append dir "/" <>)
> +       (scandir dir (lambda (filename)
> +                      (and (not (member filename '("." "..")))
> +                           (directory-exists? (string-append dir "/"
> filename)))))))
> +
> +(define* (configure #:key inputs mix-path mix-exs #:allow-other-
> keys)
> +  "Set environment variables.
> +See:
> https://hexdocs.pm/mix/1.15.7/Mix.html#module-environment-variables"
> +  (setenv "LC_ALL" "en_US.UTF-8")
> +  (setenv "MIX_HOME" (getcwd))
> +  (setenv "MIX_ARCHIVES" "archives")
> +  (setenv "MIX_BUILD_ROOT" "_build")
> +  (setenv "MIX_DEPS_PATH" "deps")
> +  (setenv "MIX_PATH" (or mix-path ""))
> +  (setenv "MIX_REBAR3" (string-append (assoc-ref inputs "rebar3")
> "/bin/rebar3"))
> +  (setenv "MIX_EXS" mix-exs))
This does not appear to be a configure phase in the traditional sense
of the wording.  Instead, it should be a post 'set-paths' 'set-mix-env'
imho.

> +(define* (install-hex #:key name inputs outputs #:allow-other-keys)
> +  "Install Hex."
> +  (let ((hex-archive-path (string-append (getenv "MIX_ARCHIVES")
> "/hex")))
> +    (mkdir-p hex-archive-path)
> +    (symlink (car (list-directories (elixir-libdir (assoc-ref inputs
> "elixir")
> +                                                   (assoc-ref inputs
> "elixir-hex"))))
> +             (string-append hex-archive-path "/hex"))))
Why do we need this?  It looks like we'll be pasting the same (native?)
input all over the store, which imho would be bad.

> +(define* (install-dependencies #:key
> +                               name
> +                               inputs
> +                               outputs
> +                               tests?
> +                               build-per-environment
> +                               (native-inputs '())
> +                               mix-environments
> +                               #:allow-other-keys
> +                               #:rest rest)
> +  "Install dependencies."
> +  (define (install-lib lib dir)
> +    (let ((lib-name (last (string-split lib #\/))))
> +      (symlink lib (string-append dir "/" lib-name))))
> +
> +  (define (install-input mix-env input)
> +    (let ((dir (mix-build-dir mix-env)))
> +      (mkdir-p dir)
> +      (match input
> +        ((_ . path)
> +         ((compose
> +           (cut for-each (cut install-lib <> dir) <>)
> +           (cut append-map list-directories <>)
> +           (cut filter directory-exists? <>))
> +          (list (elixir-libdir (assoc-ref inputs "elixir") path)
> +                (erlang-libdir path)))))))
I think you're at the wrong layer of abstraction here.

  (match input 
    ((_ . prefix)
     (begin 
      (install-subdirectories (elixir-libdir path))
      (install-subdirectories (erlang-libdir path)))))

where (install-subdirectories PATH) is basically
  (when (directory-exists? PATH)
    (for-each (cute install-lib <> (mix-build-dir mix-env))
              (list-directories PATH)))

> +  (define (install-inputs mix-env)
> +    (for-each (cut install-input mix-env <>)
> +              (append inputs native-inputs)))
Installing native inputs: probably a bad idea (inhibits cross-
compilation).

> +  (for-each install-inputs mix-environments))
> +
> +(define* (build #:key mix-environments #:allow-other-keys)
> +  "Builds the Mix project."
> +  (for-each (lambda (mix-env)
> +              (setenv "MIX_ENV" mix-env)
> +              (invoke "mix" "compile" "--no-deps-check"))
> +            mix-environments))
> +
> +(define* (check #:key (tests? #t) #:allow-other-keys)
> +  "Test the Mix project."
> +  (if tests?
> +      (invoke "mix" "test" "--no-deps-check")
> +      (format #t "tests? = ~a~%" tests?)))
> +
> +(define* (remove-mix-dirs . _)
> +  "Remove all .mix/ directories.
> +We do not want to copy them to the installation directory."
> +  (for-each delete-file-recursively
> +            (find-files "." (file-name-predicate "\\.mix$")
> #:directories? #t)))
> +
> +(define (library-name pkg-name)
> +  "Return the library name deduced from PKG-NAME.
> +A package should be named: elixir-lib-name-X.Y.Z from which the
> library name
> +lib_name is deduced."
> +  ((compose
> +    (cut string-join <> "_")
> +    (cut drop-right <> 1)
> +    (cut string-split <> #\-))
> +   (strip-elixir-prefix pkg-name)))
Consider defining (package-name-version->elixir-name) analogous to
(package-name-version->erlang-name) in rebar-build-system.  Also allow
overriding it through a build system argument.  The thing you currently
have will blow up with git-version.

Cheers