Packaging:Ruby

Ruby Packaging Guidelines

Each Ruby package must indicate the Ruby ABI version it depends on with a line like

Requires: ruby(abi) = 1.8

Ruby packages must require ruby at build time with a BuildRequires: ruby, and may indicate the minimal ruby version they need for building.

Naming Guidelines

These naming guidelines only apply to ruby packages whose main purpose is providing a Ruby library; packages that mainly provide user-level tools that happen to be written in Ruby do not need to follow these naming guidelines, and should follow the general NamingGuidelines instead.

The name of a ruby extension/library package must be of the form ruby-UPSTREAM. If the upstream name UPSTREAM contains ruby, that should be dropped from the name. For example, the SQLite database driver for ruby is called sqlite3-ruby. The corresponding Fedora package should be called ruby-sqlite3, and not ruby-sqlite3-ruby.

A ruby extension/library package must indicate what it provides with a Provides: ruby(LIBRARY) = VERSION declaration in the spec file. The string LIBRARY should be the same as what is used in the require statement in a Ruby script that uses the library. The VERSION should be the upstream version of the library, as long as upstream follows a sane versioning scheme. For example, a Ruby script using the SQLite database driver will include it with require 'sqlite3'. The specfile for the corresponding Fedora package must contain a line Provides: ruby(sqlite3) = 1.1.0, assuming the package contains version 1.1.0 of the library.

Build Architecture and File Placement

The following only affects the files that the package installs into %{_libdir}/ruby, i.e., Ruby library files. All other files in a Ruby package must adhere to the general Fedora Extras packaging conventions.

Pure Ruby packages

Pure Ruby packages must be built as noarch packages.

The Ruby library files in a pure Ruby package must be placed into Config::CONFIG["sitelibdir"] . The specfile must get that path using

%{!?ruby_sitelib: %define ruby_sitelib %(ruby -rrbconfig -e 'puts Config::CONFIG["sitelibdir"] ')}

For Fedora Core 3 and earlier releases, it is not possible to build noarch packages; for those releases, all Ruby packages must be architecture-specific, even if they only contain Ruby files. (See bug 184199 for details)

Ruby packages with binary content/shared libraries

For packages with binary content, e.g., database drivers or any other Ruby bindings to C libraries, the package must be architecture specific.

The binary files in a Ruby package with binary content must be placed into Config::CONFIG["sitearchdir"] . The Ruby files in such a package should be placed into that directory, too. The specfile must get that path using

%{!?ruby_sitearch: %define ruby_sitearch %(ruby -rrbconfig -e 'puts Config::CONFIG["sitearchdir"] ')}

Ruby Gems

Ruby Gems are Ruby's own packaging format. Gems contain a lot of the same metadata that RPM's need, making fairly smooth interoperation between RPM and Gems possible. This guideline ensures that Gems are packaged as RPM's in a way that ensures (1) that such RPM's fit cleanly with the rest of the distribution and (2) make it possible for the end user to satisfy dependencies of a Gem by installing the appropriate RPM-packaged Gem.

Both RPM's and Gems use similar terminology --- there's specfiles, package names, dependencies etc. for both. To keep confusion to a minimum, whenever the term from the Gem world is meant, it is explicitly called the 'Gem specification'. An unqualified 'package' in the following always means an RPM.

• Packages that contain Ruby Gems must be called rubygem-%{gemname} where gemname is the name from the Gem's specification.
• The Source of the package must be the full URL to the released Gem archive; the version of the package must be the Gem's version
• The package must have a Requires and a BuildRequires on rubygems
• The package must provide rubygem(%{gemname}) where gemname is the name from the Gem's specification. For every dependency on a Gem named gemdep, the package must contain a Requires on rubygem(%{gemdep}) with the same version constraints as the Gem
• The %prep and %build sections of the specfile should be empty.
• The Gem must be installed into %{gemdir} defined as

%define gemdir %(ruby -rubygems -e 'puts Gem::dir' 2>/dev/null)

The install should be performed with the command

gem install --local --install-dir %{buildroot}%{gemdir} --force %{SOURCE0}

• The package must own the following files and directories:

%{gemdir}/gems/%{gemname}-%{version}/
%{gemdir}/cache/%{gemname}-%{version}.gem
%{gemdir}/specifications/%{gemname}-%{version}.gemspec

• Architecture-specific content must not be installed into %{gemdir}
• If the Gem only contains pure Ruby code, it must be marked as BuildArch: noarch. If the Gem contains binary content (e.g., for a database driver), it must be marked as architecture specific, and all architecture specific content must be moved from the %{gemdir} to the [#ruby_sitearch %{ruby_sitearch} directory] during %install

Packaging for Gem and non-Gem use

If the same Ruby library is to be packaged for use as a Gem and as a straight Ruby library without Gem support, it must be packaged as a Gem first. To make it available to code that does not use Ruby Gems, a subpackage called ruby-%{gemname} must be created in the rubygem-%{gemname} package such that

• The subpackage must require rubygem(%gemname) = %version
• The subpackage must provide ruby(LIBRARY) = %version where LIBRARY is the same as in the [#ruby_naming general Ruby guideline] above.
• All the toplevel library files of the Gem must be symlinked into ruby_sitelib.
• The subpackage must own these symbolic links.

As an example, for activesupport, the rubygem-activesupport package would have a subpackge ruby-activesupport:

%package -n ruby-activesupport
...
Requires: rubygem(activesupport) = %version
Provides: ruby(active_support) = %version  # The underscore is intentional, not a typo
...
%files -n ruby-activesupport
%{ruby_sitelib}/active_support
%{ruby_sitelib}/active_support.rb

Tips for Packagers

Gems carry a lot of metadata; Gem2Spec is a tool to generate an initial specfile and/or source RPM from a Gem. The generated specfile still needs some hand-editing, but conforms to 90% with this guideline.