Perl software in
GNU Guix

Through Guix you can...

Get and use Perl

Get and use Perl modules

Get and use tools and applications written in Perl

Getting Perl

→ guix install perl

...

→ perl --version

This is perl 5, version 28, subversion 0 (v5.28.0) built for
x86_64-linux-thread-multi

...

Using Perl modules

→ guix install perl perl-uri

...

→ echo $PERL5LIB
/gnu/store/h3ryiwyhp8qcxyf74sxyv746171zpazr-profile/lib/perl5/site_perl

→ ls /gnu/store/h3r...azr-profile/lib/perl5/site_perl/5.28.0/
URI  URI.pm  x86_64-linux-thread-multi

Wiki compiler
Static site generator
I occasionally use it for blogging

cbaines pushed a change to branch master
in repository guix.

      from  921bb35   gnu: linux-libre@4.9: Fix hash.
       new  31d3a7c   gnu: Add discount.
       new  9d46919   gnu: Add perl-text-markdown-discount.
       new  19d81cf   gnu: Add perl-test-cpan-meta-json.
       new  d5b5020   gnu: Add perl-test-cpan-meta.
       new  b4387d8   gnu: Add perl-devel-cycle.
       new  3d74955   gnu: Add perl-test-memory-cycle.
       new  8800255   gnu: Add perl-test-notabs.
       new  7d1f9c9   gnu: Add perl-test-eol.
       new  4f0ee1b   gnu: Add perl-html-scrubber.
       new  86bd64b   gnu: Add perl-yaml-libyaml.
       new  f0539b6   gnu: Add perl-cgi-session.
       new  909dcf5   gnu: Add ikiwiki.

(define-public ikiwiki
  (package
    (name "ikiwiki")
    (version "3.20190228")
    (source
     (origin
       (method url-fetch)
       (uri (string-append "http://snapshot.debian.org/archive/debian/"
                           "20190301T035241Z/pool/main/i/ikiwiki/ikiwiki_"
                           version ".orig.tar.xz"))
       (sha256
        (base32
         "17pyblaqhkb61lxl63bzndiffism8k859p54k3k4sghclq6lsynh"))))
  ...

Packages in Guix are defined through a record type in Guile scheme. I've only done a little bit of Perl programming, but I think it has a concept of a record as well. So, `define-public ikiwiki` is defining a value called `ikiwiki`, which is a package. (next) Next there are some fields in the package record. The package has a name, and the version is also specified. (next) Then the `source` is defined. This says to fetch something from a URL. In this case, the Ikiwiki package is a little odd. Normally this would be a release tarball from the upstream authors, not the snapshot.debian.org site. Importantly, the expected hash of the file is also specified. This means there'll be no surprises, and that the behaviour will be consistent in to the future.

(define-public ikiwiki
  (package
    ...
    (build-system perl-build-system)
    (arguments
     `(#:phases
        (modify-phases %standard-phases
         (add-after 'unpack 'include-PERL5LIB-in-wrapper
           (lambda _
             (substitute* "IkiWiki/Wrapper.pm"
               (("^@wrapper\\_hooks")
                (string-append
                 "@wrapper_hooks\n"
                 "        addenv(\"PERL5LIB\", \""
                 (getenv "PERL5LIB")
                 "\");")))))
         (add-after 'patch-source-shebangs 'patch-Makefile
           (lambda _
             (substitute* "Makefile.PL"
               (("SYSCONFDIR\\?=") "SYSCONFDIR?=$(PREFIX)"))
             #t))
         (add-after 'install 'wrap-programs
           (lambda* (#:key outputs #:allow-other-keys)
             (let* ((out  (assoc-ref outputs "out"))
                    (bin  (string-append out "/bin/"))
                    (path (getenv "PERL5LIB")))
               (for-each (lambda (file)
                           (wrap-program file
                             `("PERL5LIB" ":" prefix (,path))))
                         (find-files bin))
             #t))))))
  ...

Moving on, each package has a build system. There are quite a few build systems, each representing common build steps that apply to multiple packages. In this case, Ikiwiki uses the perl-build-system. This will look for files like Build.PL and Makefile.PL, and use them if they exist. (next) The build system can be passed some arguments. Here, some of the phases of the build process are being tweaked. (next) After the `'unpack` phase, there's a small change being made to the source code. The value of the PERL5LIB environment variable is being included in a file. This is so Ikiwiki can find the modules it requires at runtime. (next) The Makefile is then patched to have the example configuration installed. Often this isn't necessary. Finally, one common step is wrapping the files within the bin directory with the value of the PERL5LIB environment variable. This is also to ensure that Ikiwiki can find the modules it requires at runtime.

(define-public ikiwiki
  (package
    ...
    (native-inputs
     `(("which" ,which)
       ("perl-html-tagset" ,perl-html-tagset)
       ("perl-timedate" ,perl-timedate)
       ("perl-xml-sax" ,perl-xml-sax)
       ("perl-xml-simple" ,perl-xml-simple)
       ("gettext" ,gettext-minimal)
       ("subversion" ,subversion)
       ("git" ,git)
       ("bazaar" ,bazaar)
       ("cvs" ,cvs)
       ("mercurial" ,mercurial)))
    (inputs
     `(("python" ,python-wrapper)
       ("perl-cgi-formbuilder" ,perl-cgi-formbuilder)
       ("perl-cgi-session" ,perl-cgi-session)
       ("perl-cgi-simple" ,perl-cgi-simple)
       ("perl-db-file" ,perl-db-file)
       ("perl-html-parser" ,perl-html-parser)
       ("perl-html-scrubber" ,perl-html-scrubber)
       ("perl-html-template" ,perl-html-template)
       ("perl-image-magick" ,perl-image-magick)
       ("perl-json" ,perl-json)
       ("perl-text-markdown-discount" ,perl-text-markdown-discount)
       ("perl-uri" ,perl-uri)
       ("perl-yaml-libyaml" ,perl-yaml-libyaml)))
  ...

Next come the inputs to the package. The terminology comes from the "functional" package management paradigm that Guix uses. If you consider a building a package a function, the dependencies are inputs to that function, and the output of the function is the built package in the store. There are multiple types of inputs, native-inputs are those that are just used at build time. Whereas inputs are used at runtime, and maybe also when the package is being built. The distinction is mostly important when cross compiling, something which the Perl build system doesn't currently support as far as I'm aware. Thinking back to the use of the PERL5LIB environment variable on the previous slide, these are the modules which will be mentioned in the value of that environment variable. When building a Guix package, the build process takes place in an isolated environment, with only the store items that the package and build system explicitly require, along with their dependnecies. Guix will ensure that any store item referenced by the generated outputs exists within the store. Which it's why it's important for the Ikiwiki package to reference the modules it requires explicitly. This is similar to what other package managers do with the notion of dependencies, except in Guix it's much more specific and unchanging.

(define-public ikiwiki
  (package
    ...
    (home-page "https://ikiwiki.info/")
    (synopsis "Wiki compiler, capable of generating HTML")
    (description
     "Ikiwiki is a wiki compiler, capable of generating a static set of web
pages, but also incorporating dynamic features like a web based editor and
commenting.")
    (license license:gpl2+)))

→ guix build ikiwiki

...

/gnu/store/hcrv2cqzbisdb35hg2xmbxp1r2z7ijzd-ikiwiki-3.20190228

/gnu/store/hcrv2cqzbisdb35hg2xmbxp1r2z7ijzd-ikiwiki-3.20190228
├── bin
│   ├── ikiwiki
│   ├── ikiwiki-calendar
│   ├── ikiwiki-comment
│   ├── ikiwiki-makerepo
│   ├── ikiwiki-transition
│   └── ikiwiki-update-wikilist
├── etc
│   └── ikiwiki
│       └── ...
├── lib
│   ├── ikiwiki
│   │   └── ...
│   ├── perl5
│   │   └── ...
│   └── w3m
│       └── cgi-bin
│           └── ikiwiki-w3m.cgi
├── sbin
│   └── ikiwiki-mass-rebuild
└── share
    ├── ikiwiki
    │   └── ...
    ├── locale
    │   └── ...
    └── man
        ├── man1
        │   └── ...
        └── man8
            └── ikiwiki-mass-rebuild.8.gz

Sensible database change management

cbaines pushed a change to branch master
in repository guix.

      from  1b7436a   gnu: wine-staging: Update to 4.6.
       new  41c685f   gnu: Add perl-http-tinyish.
       new  ef9902d   gnu: Add perl-config-gitlike.
       new  366b76c   gnu: Add perl-cpan-distnameinfo.
       new  54a5178   gnu: Add perl-tie-handle-offset.
       new  f73d4b1   gnu: Add perl-io-pager.
       new  e748fbe   gnu: Add perl-string-formatter.
       new  9273ebf   gnu: Add perl-template-tiny.
       new  ce6bea4   gnu: Add perl-uri-nested.
       new  618d52a   gnu: Add perl-uri-db.
       new  c1a4e78   gnu: Add perl-test-checkdeps.
       new  9c5551c   gnu: Add perl-test-dir.
       new  402cfeb   gnu: Add perl-test-file.
       new  709a9e9   gnu: Add perl-test-file-contents.
       new  3840c51   gnu: Add perl-test-version.
       new  55916fa   gnu: Add perl-mysql-config.
       new  7b23313   gnu: Add perl-string-shellquote.
       new  cabe8f1   gnu: Add sqitch.

→ guix import cpan HTTP::Tinyish

Starting download of /tmp/guix-file.f6bYLw
From http://www.cpan.org/authors/id/M/MI/MIYAGAWA/HTTP-Tinyish-0.15.tar.gz...
 …-0.15.tar.gz  16KiB                 722KiB/s 00:00 [##################] 100.0%
(package
  (name "perl-http-tinyish")
  (version "0.15")
  (source
    (origin
      (method url-fetch)
      (uri (string-append
             "mirror://cpan/authors/id/M/MI/MIYAGAWA/HTTP-Tinyish-"
             version
             ".tar.gz"))
      (sha256
        (base32
          "199sa722amvwhq0czjfb7psj3hbqmvni5vxkrm579r5943pg0rax"))))
  (build-system perl-build-system)
  (propagated-inputs
    `(("perl-file-which" ,perl-file-which)
      ("perl-ipc-run3" ,perl-ipc-run3)))
  (home-page
    "https://metacpan.org/release/HTTP-Tinyish")
  (synopsis
    "HTTP::Tiny compatible HTTP client wrappers")
  (description fill-in-yourself!)
  (license perl-license))

Recap: Through Guix you can...