Adding a new Software Definition to Omnibus GitLab

In order to add a new component to GitLab, you should follow these steps:

  1. Fetch and compile the software during build
  2. Add a dependency for the software definition to another component

Fetch and compile the software during build

Software Definitions, which can be found in /config/software, specify where omnibus should fetch the software, how to compile it and install it to the required folder. This part of the project is run when we build the Omnibus package for GitLab.

When adding a component that should be fetched from Git the clone address of the repositories of the local mirror and upstream should be added to /.custom_sources.yml.

The local mirror should be created in the omnibus-mirror project by a member of the Distribution team.

See other Software services in the directory for examples on how to include your software service.

Handling Licenses

Most software repositories include a license file. Add the license using a patch file if it is not explicitly included. Software installed using a package manager such as gem or pip should also use this method.

Create patches for licenses added manually and store them at a directory path with the naming convention config/patches/SOFTWARE_NAME/license/VERSION_NUMBER/add-license-file.patch.

Licenses can and do change over the lifetime of a project. This method intentionally causes builds to fail reminding contributors to verify manually installed licenses. If the license has not changed then git mv the VERSION_NUMBER directory containing the patch file to the new VERSION_NUMBER.

Add a dependency for the software definition to another component

Add a dependency statement to the definition of the GitLab project found in /config/projects/gitlab.rb, unless there is a more specific component it makes sense to be a dependency of (eg config/software/gitlab-rails.rb for a component only needed by gitlab-rails)

Omnibus will build dependency components first, and then other ones in the order of their presence in /config/projects/gitlab.rb. So, when a software component A is marked as a dependency of another software B, A will be built towards the beginning of the process. In cases where A is a component that changes frequently, cache gets invalidated often causing every subsequent component to be rebuilt, increasing overall build time. A workaround is to ensure A gets built immediately before B, avoiding cache invalidation.

  1. Add the software A to /config/projects/gitlab.rb immediately before software B

    Since A and B are now top-level dependencies of the project, omnibus will build them in the order of their presence in /config/projects/gitlab.rb.

  2. In the software definition of B, add a line similar to the following

    dependency '<name of software A>' unless project.dependencies.include?('<name of software A>')

    Above ensures that whenever the project is not built from /config/projects/gitlab.rb, A is marked as a dependency of B and is built before B. There will be no effect on builds from /config/projects/gitlab.rb however.

Validating changes to a single software dependency

It can be useful to only build one piece of software, rather than rebuild the whole package each time. For instance, when adding a new software definition. Using this method, you can quickly rebuild an omnibus package containing only the software and its dependencies. Once you’ve confirmed the software builds on its own, you can add it to the Omnibus GitLab build and confirm it there. To use this:

  1. Setup your development environment
  2. Copy the simple.rb file into your projects

    cp doc/development/examples/simple.rb config/projects/
  3. Change the dependency in config/projects/simple.rb to match the software you are testing
  4. Build the simple project by running

    bundle exec omnibus build simple