Balrog is Mozilla's update server. It is responsible for delivering newer versions of Firefox to existing Firefox installations. If you are not already, it would be useful to be familiar with Balrog's core concepts before continuing with this doc. You can find that information on Balrog's official documentation.
The basic interactions that Release Promotion has with Balrog are as follows:
balrogtasks and the
Balrog requires many different pieces of information before it can ship updates. Most of this information revolves around update file (MAR) metadata (hash, filesize, target platform, target locale). This information is submitted by
We also submit some more general information about releases (version number, MAR url templates, release name, etc.) as part of the
All balrog submission is done by balrogscript workers, and happens in the
Balrog has "test" channels that we use to allow verification of new release updates prior to shipping. The
release-balrog-submit-toplevel task is responsible for updating these test channels whenever we prepare a new release. This happens in the
Once a release is live on a test channel
release-update-verify begins and performs same sanity checks. This happens in the
After a release has been pushed to cdns,
release-final-verify runs and performs some additional checks. This happens in the
When we're ready to ship a release we need to let Balrog know about it by scheduling a change to the appropriate Balrog rule. If
release_eta is set it will be used as the ship date and time. If not, the release will be scheduled for shipping 5 minutes in the future. In either case, signoff will need to be done in Balrog by multiple parties before the release is actually made live.
This step is done by the
release-balrog-scheduling task in the
You may have noticed
secondary variants of the
release-balrog-scheduling tasks. These fulfill the same function as their primary counterparts, but for the "beta" update channel. They are only used when we build Release Candidates.