author Joel Maher <jmaher@mozilla.com>
Wed, 11 Oct 2017 08:45:06 -0400
changeset 432365 42c1b2dc8bac015e691fb2e17c95f60f6cb144aa
parent 426147 080373b666c8f8d6f7b4ca67acce90c4469d4d22
child 434487 a6d12cead25a83c94ab48943a53bd6bcd421524f
permissions -rw-r--r--
Bug 1396803 - Disable test_tabbar_session_restore_button.py TestNoTabbarSessionRestoreButton.test_pref_off_button_does_not_show on osx for frequent failures. r=me, a=test-only

Mach commands

A number of mach subcommands are available aside from ``mach taskgraph
decision`` to make this complex system more accessible to those trying to
understand or modify it.  They allow you to run portions of the
graph-generation process and output the results.

``mach taskgraph tasks``
   Get the full task set

``mach taskgraph full``
   Get the full task graph

``mach taskgraph target``
   Get the target task set

``mach taskgraph target-graph``
   Get the target task graph

``mach taskgraph optimized``
   Get the optimized task graph

``mach taskgraph morphed``
   Get the morhped task graph

Each of these commands takes an optional ``--parameters`` option giving a file
with parameters to guide the graph generation.  The decision task helpfully
produces such a file on every run, and that is generally the easiest way to get
a parameter file.  The parameter keys and values are described in
:doc:`parameters`; using that information, you may modify an existing
``parameters.yml`` or create your own.  The ``--parameters`` option can also
take an argument of the form ``project=<project>`` which will fetch the
parameters from the latest push on that project; or ``task-id=<task-id>`` which
will fetch the parameters from the given decision task. It defaults to

See :doc:`how-tos` for further practical tips on debugging task-graph mechanics

Taskgraph JSON Format
By default, the above commands will only output a list of tasks. Use `-J` flag
to output full task definitions. For example:

.. code-block:: shell

    $ ./mach taskgraph optimized -J

Task graphs -- both the graph artifacts produced by the decision task and those
output by the ``--json`` option to the ``mach taskgraph`` commands -- are JSON
objects, keyed by label, or for optimized task graphs, by taskId.  For
convenience, the decision task also writes out ``label-to-taskid.json``
containing a mapping from label to taskId.  Each task in the graph is
represented as a JSON object.

Each task has the following properties:

   The name of this task's kind

   The task's taskId (only for optimized task graphs)

   The task's label

   The task's attributes

   The task's in-graph dependencies, represented as an object mapping
   dependency name to label (or to taskId for optimized task graphs)

   The optimizations to be applied to this task

   The task's TaskCluster task definition.

The results from each command are in the same format, but with some differences
in the content:

* The ``tasks`` and ``target`` subcommands both return graphs with no edges.
  That is, just collections of tasks without any dependencies indicated.

* The ``optimized`` subcommand returns tasks that have been assigned taskIds.
  The dependencies array, too, contains taskIds instead of labels, with
  dependencies on optimized tasks omitted.  However, the ``task.dependencies``
  array is populated with the full list of dependency taskIds.  All task
  references are resolved in the optimized graph.

The output of the ``mach taskgraph`` commands are suitable for processing with
the `jq <https://stedolan.github.io/jq/>`_ utility.  For example, to extract all
tasks' labels and their dependencies:

.. code-block:: shell

    jq 'to_entries | map({label: .value.label, dependencies: .value.dependencies})'

An alternate way of searching the output of ``mach taskgraph`` is
`gron <https://github.com/tomnomnom/gron>`_, which converts json into a format
that's easily searched with ``grep``

.. code-block:: shell

    gron taskgraph.json | grep -E 'test.*machine.platform = "linux64";'
    ./mach taskgraph --json | gron | grep ...