Release tooling¶

Ferrocene is developed using a custom tool, publish-release, which is responsible for all of the release steps. The tool is written in Rust and developed in the ferrocene/publish-release repository, and it’s executed on GitHub Actions in the ferrocene/ferrocene repository.

When GitHub Actions invokes the release tool, the calculate-release-job-matrix.py script is used to determine which commit(s) to instruct the release process to release. The script does little when starting a manual release, but it’s fully responsible for determining which scheduled releases to run.

Publishing a manual release¶

Our release tooling also allows to manually start the release process. This can be useful to start releases that are not on a schedule, to restart a scheduled release that failed, or for testing (in the dev environment). Only starting the release is manual, all the actual steps are fully automated.

To manually start a release, go to the release workflow page and click the “Run workflow” button. You need to input the git reference you want to release (it can be a branch name, a short commit hash, or a full commit hash), and the environment to release in. Note that anyone can publish a release in the dev environment, while approval from a release manager is required for the prod environment.

It’s also possible to override some of the startup checks the release process performs, and to treat the git reference as verbatim instead of trying to resolve it. The latter option is useful if you need to release a commit which is not present in the ferrocene/ferrocene repository.

Once you click the green “Run workflow” button a new job will be queued.

If the release targets the prod environment an approval from a release manager will be required. The release manager will need to approve the release in the GitHub UI before the release can proceed. Once it’s done, the release process will start automatically.

If there is a service outage preventing you from manually starting a release follow the instructions in Releasing during outages.

Channel names¶

The release channel is determined automatically by the tooling, based on both the src/ci/channel file (managed by upstream) and the ferrocene/ci/channel file (managed by Ferrocene):

We rely on this approach of combining the two files to determine the channel (rather than storing the actual channel in ferrocene/ci/channel) to reduce the maintenance efforts.

This way, as long as we set ferrocene/ci/channel to “rolling” on the main branch, we don’t need to make any change ourselves to promote a branch from “nightly” to “pre-rolling” to “rolling”, as upstream does that for us when they change src/ci/channel.