Task Attributes

Tasks can be filtered, for example to support “try” pushes which only perform a subset of the task graph or to link dependent tasks. This filtering is the difference between a full task graph and a target task graph.

Filtering takes place on the basis of attributes. Each task has a dictionary of attributes and filters over those attributes can be expressed in Python. A task may not have a value for every attribute.

The attributes, and acceptable values, are defined here. In general, attribute names and values are the short, lower-case form, with underscores.


A task’s kind attribute gives the name of the kind that generated it, e.g., build or spidermonkey.


The projects where this task should be in the target task set. This is how requirements like “only run this on inbound” get implemented. These are either project names or the aliases

  • integration – integration repositories (autoland, inbound, etc)
  • trunk – integration repositories plus mozilla-central
  • release – release repositories including mozilla-central
  • all – everywhere (the default)

For try, this attribute applies only if -p all is specified. All jobs can be specified by name regardless of run_on_projects.

If run_on_projects is set to an empty list, then the task will not run anywhere, unless its build platform is specified explicitly in try syntax.


On a given project, the mercurial branch where this task should be in the target task set. This is how requirements like “only run this RELBRANCH” get implemented. These are either the regular expression of a branch (e.g.: “GECKOVIEW_d+_RELBRANCH”) or the following alias:

  • all – everywhere (the default)

Like run_on_projects, the same behavior applies if it is set to an empty list.


This is used to indicate that we want multiple copies of the task created. This feature is used to track down intermittent job failures.

If this value is set to N, the task-creation machinery will create a total of N copies of the task. Only the first copy will be included in the taskgraph output artifacts, although all tasks will be contained in the same taskGroup.

While most attributes are considered read-only, target task methods may alter this attribute of tasks they include in the target set.


The build platform defines the platform for which the binary was built. It is set for both build and test jobs, although test jobs may have a different test_platform.


The type of build being performed. This is a subdivision of build_platform, used for different kinds of builds that target the same platform. Values are

  • debug
  • opt


The test platform defines the platform on which tests are run. It is only defined for test jobs and may differ from build_platform when the same binary is tested on several platforms (for example, on several versions of Windows). This applies for both talos and unit tests.

Unlike build_platform, the test platform is represented in a slash-separated format, e.g., linux64/opt.


This is the unit test suite being run in a unit test task. For example, mochitest or cppunittest.


If a unittest suite has subdivisions, those are represented as flavors. Not all suites have flavors, in which case this attribute should be set to match the suite. Examples: mochitest-devtools-chrome-chunked or a11y.


This is the name used to refer to a unit test via try syntax. It may not match either of unittest_suite or unittest_flavor.


This is the name used to refer to a talos job via try syntax.


This is the name used to refer to a raptor job via try syntax.


This is the name used to refer to a “job” via try syntax (-j). Note that for some kinds, -j also matches against build_platform.


This is the chunk number of a chunked test suite (talos or unittest). Note that this is a string!


For test suites which distinguish whether or not they run with the serviceworker e10s redesign enabled.


For test suites which distinguish whether they run with or without e10s, this boolean value identifies this particular run.


For the docker_image kind, this attribute contains the docker image name.


Signals whether the task is part of a nightly graph. Useful when filtering out nightly tasks from full task set at target stage.


For the l10n and nightly-l10n kinds, this attribute contains the list of relevant locales for the platform.


Contains a dict of l10n changesets, mapped by locales (same as in all_locales).


For the l10n and nightly-l10n kinds, this attribute contains the chunk number of the job. Note that this is a string!


For the l10n and nightly-l10n kinds, this attribute contains an array of the individual locales this chunk is responsible for processing.


For jobs that operate on only one locale, we set the attribute locale to the specific locale involved. Currently this is only in l10n versions of the beetmover and balrog kinds.


Signals that the output of this task contains signed artifacts.


Signals to the build system that this build is expected to have a stub installer present, and informs followon tasks to expect it.


This is the type of repackage. Can be repackage or repackage_signing.


For fetch jobs, this is the path to the artifact for that fetch operation.


For toolchain jobs, this is the path to the artifact for that toolchain.


For toolchain jobs, this optionally gives an alias that can be used instead of the real toolchain job name in the toolchains list for build jobs.


Tasks with this attribute will be included in the target_task_graph regardless of any target task filtering that occurs. When a task is included in this manner (i.e it otherwise would have been filtered out), it will be considered for optimization even if the optimize_target_tasks parameter is False.

This is meant to be used for tasks which a developer would almost always want to run. Typically these tasks will be short running and have a high risk of causing a backout. For example lint or python-unittest tasks.


For release promotion jobs, this is the product we are shipping.


For release promotion jobs, this is the shipping phase (build, promote, push, ship). During the build phase, we build and sign shippable builds. During the promote phase, we generate l10n repacks and push to the candidates directory. During the push phase, we push to the releases directory. During the ship phase, we update bouncer, push to Google Play, version bump, mark as shipped in ship-it.

Using the “snowman model”, we depend on previous graphs if they’re defined. So if we ask for a push (the head of the snowman) and point at the body and base, we only build the head. If we don’t point at the body and base, we build the whole snowman (build, promote, push).


Most taskcluster artifacts are public, so we’ve hardcoded public/build in a lot of places. To support private artifacts, we’ve moved this to the artifact_prefix attribute. It will default to public/build but will be overrideable per-task.


In automation, full crashsymbol package generation is normally disabled. For build kinds where the full crashsymbols should be enabled, set this attribute to True. The full symbol packages will then be generated and uploaded on release branches and on try.


Indicates that a task is meant to be run via cron tasks, and should not be run on push.


Some tasks generate artifacts that are cached between pushes. This is the unique string used to identify the current version of the artifacts. See taskgraph.util.cached_task.


Some tasks generate artifacts that are cached between pushes. This is the type of cache that is used for the this task. See taskgraph.util.cached_task.