Task Kinds

This section lists and documents the available task kinds.


Builds are tasks that produce an installer or other output that can be run by users or automated tests. This is more restrictive than most definitions of “build” in a Mozilla context: it does not include tasks that run build-like actions for static analysis or to produce instrumented artifacts.


Many builds must be signed. The build-signing task takes the unsigned build kind artifacts and passes them through signingscriptworker to a signing server and returns signed results.


This kind performs an artifact build: one based on precompiled binaries discovered via the TaskCluster index. This task verifies that such builds continue to work correctly.


Hazard builds are similar to “regular’ builds, but use a compiler extension to extract a bunch of data from the build and then analyze that data looking for hazardous behaviors.


The l10n kind takes the last published nightly build, and generates localized builds from it. You can read more about how to trigger these on the wiki.


The nightly l10n kind repacks a specific nightly build (from the same source code) in order to provide localized versions of the same source.


The nightly l10n signing kind takes artifacts from the nightly-l10n kind and passes them to signing servers to have their contents signed appropriately, based on an appropriate signing format. One signing job is created for each nightly-l10n job (usually chunked).


Source-tests are tasks that run directly from the Gecko source. This can include linting, unit tests, source-code analysis, or measurement work. While source-test tasks run from a source checkout, it is still possible for them to depend on a build artifact, though often they do not.


Upload-symbols tasks run after builds and upload the symbols files generated by build tasks to Socorro for later use in crash analysis.


Upload-generated-sources tasks run after builds and upload source files that were generated as part of the build process to an s3 bucket for later use in links from crash reports or when debugging shipped builds.


Valgrind tasks produce builds instrumented by valgrind.


Searchfox builds generate C++ index data for Searchfox.


Static analysis builds use the compiler to perform some detailed analysis of the source code while building. The useful output from these tasks are their build logs, and while they produce a binary, they do not upload it as an artifact.


Toolchain builds create the compiler toolchains used to build Firefox. These will eventually be dependencies of the builds themselves, but for the moment are run manually via try pushes and the results uploaded to tooltool.


Spidermonkey tasks check out the full gecko source tree, then compile only the spidermonkey portion. Each task runs specific tests after the build.


The desktop-test kind defines tests for builds. Its tests.yml defines the full suite of desktop tests and their particulars, leaving it to the transforms to determine how those particulars apply to the various platforms.

The process of generating tests goes like this, based on a set of YAML files named in kind.yml:

  • For each build task, determine the related test platforms based on the build platform. For example, a Windows 2010 build might be tested on Windows 7 and Windows 10. Each test platform specifies “test sets” indicating which tests to run. This is configured in the file named test-platforms.yml.
  • Each test set is expanded to a list of tests to run. This is configured in the file named by test-sets.yml. A platform may specify several test sets, in which case the union of those sets is used.
  • Each named test is looked up in the file named by tests.yml to find a test description. This test description indicates what the test does, how it is reported to treeherder, and how to perform the test, all in a platform-independent fashion.
  • Each test description is converted into one or more tasks. This is performed by a sequence of transforms defined in the transforms key in kind.yml. See Transforms: for more information on these transforms.
  • The resulting tasks become a part of the task graph.


This process generates all test jobs, regardless of tree or try syntax. It is up to a later stages of the task-graph generation (the target set and optimization) to select the tests that will actually be performed.


Tasks of the docker-image kind build the Docker images in which other Docker tasks run.

The tasks to generate each docker image have predictable labels: build-docker-image-<name>.

Docker images are built from subdirectories of taskcluster/docker, using docker build. There is currently no capability for one Docker image to depend on another in-tree docker image, without uploading the latter to a Docker repository

The task definition used to create the image-building tasks is given in image.yml in the kind directory, and is interpreted as a YAML Template.


Balrog tasks are responsible for submitting metadata to our update server (Balrog). They are typically downstream of a beetmover job that moves signed MARs somewhere (eg: beetmover and beetmover-l10n for releases, beetmover-repackage for nightlies).


Beetmover, takes specific artifacts, “Beets”, and pushes them to a location outside of Taskcluster’s task artifacts, (archive.mozilla.org as one place) and in the process determines the final location and a “pretty” name (versioned product name)


Beetmover L10n, takes specific artifacts, “Beets”, and pushes them to a location outside of Taskcluster’s task artifacts, (archive.mozilla.org as one place) and in the process determines the final location and a “pretty” name (versioned product name) This separate kind uses logic specific to localized artifacts, such as including the language in the final artifact names.


Beetmover-repackage is beetmover but for tasks that need an intermediate step between signing and packaging, such as OSX. For more details see the definitions of the Beetmover kind above and the repackage kind below.


Beetmover-cdns publishes promoted releases to CDNs. This is part of release promotion.


Beetmover-source publishes release source. This is part of release promotion.


Checksums-signing take as input the checksums file generated by beetmover tasks and sign it via the signing scriptworkers. Returns the same file signed and additional detached signature.


Beetmover, takes specific artifact checksums and pushes it to a location outside of Taskcluster’s task artifacts (archive.mozilla.org as one place) and in the process determines the final location and “pretty” names it (version product name)


Download strings to display on Google Play from https://l10n.mozilla-community.org/stores_l10n/. Artifact is then used by push-apk.


PushApk publishes Android packages onto Google Play Store. Jobs of this kind take all the signed multi-locales (aka “multi”) APKs for a given release and upload them all at once.


Toplevel tasks are responsible for submitting metadata to Balrog that is not specific to any particular platform+locale. For example: fileUrl templates, versions, and platform aliases.

Toplevel tasks are also responsible for updating test channel rules to point at the Release being generated.


Performs the same function as release-balrog-submit-toplevel, but against the beta channel during RC builds.


Schedules a Release for shipping in Balrog. If a release_eta was provided when starting the Release, it will be scheduled to go live at that day and time.


Performs the same function as release-balrog-scheduling, except for the beta channel as part of RC Releases.


Binary transparency creates a publicly verifiable log of binary shas for downstream release auditing. https://wiki.mozilla.org/Security/Binary_Transparency


Generate an installer using Ubuntu’s Snap format.


Pushes Snap repackage on Snap store.


Notify when a release has been pushed to CDNs.


Notify when a release has been shipped.


Notify when an RC release has been shipped to the beta channel.


Notify when a release has been promoted.


Submits bouncer updates for releases.


Marks releases as shipped in Ship-It.


Update Bouncer’s (download.mozilla.org) “latest” aliases.


Checks Bouncer (download.mozilla.org) uptake.


Generate the per-release checksums along with the summaries


Sign the pre-release checksums produced by the above task


Submit to S3 the artifacts produced by the release-checksums task and its signing counterpart.


Verifies the contents and package of release update MARs.


Verifies the contents and package of release update MARs for RC releases.


Sign a langpack XPI and publishes it onto addons.mozilla.org.


Publishes signed langpacks to archive.mozilla.org


Verifies the contents and package of release update MARs.


Verifies the contents and package of release update MARs.


Creates configs for release-update-verify tasks


Creates configs for release-secondary-update-verify tasks


Top level Balrog blob submission & patcher/update verify config updates.


Bumps to the next version.


Generates source for the release


Signs source for the release


Generates customized versions of releases for partners.


Chunks the partner repacks by locale.


Internal signing of partner repacks.


Repackaging of partner repacks.


External signing of partner repacks.


Moves the partner repacks to S3 buckets.


Generates customized versions of releases for eme-free repacks.


Internal signing of eme-free repacks


Repackaging of eme-free repacks.


External signing of eme-free repacks.


Moves the eme-free repacks to S3 buckets.


Repackage tasks take a signed output and package them up into something suitable for shipping to our users. For example, on OSX we return a tarball as the signed output and this task would package that up as an Apple Disk Image (.dmg)


Repackage-L10n is a `Repackage` task split up to be suitable for use after l10n repacks.


Repackage-signing take the repackaged installers (windows) and update packaging (with the signed internal bits) and signs them.


Repo-Update tasks are tasks that perform some action on the project repo itself, in order to update its state in some way.


Partials takes the complete.mar files produced in previous tasks and generates partial updates between previous nightly releases and the new one. Requires a release_history in the parameters. See mach release-history if doing this manually.


Partials-signing takes the partial updates produced in Partials and signs them.


Dummy tasks to consolidate balrog dependencies to avoid taskcluster limits on number of dependencies per task.


Dummy tasks to consolidate beetmover dependencies to avoid taskcluster limits on number of dependencies per task.


Dummy tasks to consolidate beetmover-checksums dependencies to avoid taskcluster limits on number of dependencies per task.


Dummy tasks to consolidate language pack beetmover dependencies to avoid taskcluster limits on number of dependencies per task.


Tasks used to build packages for use in docker images.


Tasks used to compare pairs of Firefox builds using https://diffoscope.org/. As of writing, this is mainly meant to be used in try builds, by editing taskcluster/ci/diffoscope/kind.yml for your needs.