Bug 1648591: Remove taskgraph based cron implementation; r=aki

Differential Revision: https://phabricator.services.mozilla.com/D81270

.cron.yml

@@ -1,7 +1,6 @@
 # Definitions for jobs that run periodically.  For details on the format, see
-# `taskcluster/taskgraph/cron/schema.py`.  For documentation, see
-# `taskcluster/docs/cron.rst`.
-
+# `https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision/src/build_decision/cron/schema.yml`.
+# For documentation, see `taskcluster/docs/cron.rst`.
 ---
 
 jobs:

.taskcluster.yml

@@ -1,6 +1,5 @@
 # This file is rendered via JSON-e by
-# - mozilla-taskcluster - See
-#   https://docs.taskcluster.net/reference/integrations/mozilla-taskcluster/docs/taskcluster-yml
+# - hg-push - https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision/src/build_decision/hg_push.py
 #   {
 #     tasks_for: 'hg-push',
 #     push: {owner, comment, pushlog_id, pushdate},
@@ -10,7 +9,7 @@
 #     ownTaskId: // taskId of the task that will be created
 #   }
 #
-# - cron tasks - See taskcluster/taskgraph/cron/decision.py
+# - cron tasks - https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision/src/build_decision/cron/decision.py
 #   {
 #     tasks_for: 'cron',
 #     push: {revision, pushlog_id, pushdate, owner}

taskcluster/docs/cron.rst

@@ -11,21 +11,22 @@ In the root of the Gecko directory, you will find `.cron.yml`.  This defines
 the periodic tasks ("cron jobs") run for Gecko.  Each specifies a name, what to
 do, and some parameters to determine when the cron job should occur.
 
-See ``taskcluster/taskgraph/cron/schema.py`` for details on the format and
-meaning of this file.
+See `the scema <https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision/src/build_decision/cron/schema.yml>`_
+for details on the format and meaning of this file.
 
 How It Works
 ------------
 
 The `TaskCluster Hooks Service <https://firefox-ci-tc.services.mozilla.com/hooks>`_
 has a hook configured for each repository supporting periodic task graphs.  The
 hook runs every 15 minutes, and the resulting task is referred to as a "cron task".
-That cron task runs `./mach taskgraph cron` in a checkout of the Gecko source
-tree.
+That cron task runs the `build-decision
+<https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision>`_ image in a
+checkout of the Gecko source tree.
 
-The mach subcommand reads ``.cron.yml``, then consults the current time
-(actually the time the cron task was created, rounded down to the nearest 15
-minutes) and creates tasks for any cron jobs scheduled at that time.
+The task reads ``.cron.yml``, then consults the current time (actually the time
+the cron task was created, rounded down to the nearest 15 minutes) and creates
+tasks for any cron jobs scheduled at that time.
 
 Each cron job in ``.cron.yml`` specifies a ``job.type``, corresponding to a
 function responsible for creating TaskCluster tasks when the job runs.

taskcluster/mach_commands.py

@@ -208,43 +208,13 @@ def taskgraph_decision(self, **options):
             sys.exit(1)
 
     @SubCommand('taskgraph', 'cron',
-                description="Run the cron task")
-    @CommandArgument('--base-repository',
-                     required=False,
-                     help='(ignored)')
-    @CommandArgument('--head-repository',
-                     required=True,
-                     help='URL for "head" repository to fetch')
-    @CommandArgument('--head-ref',
-                     required=False,
-                     help='(ignored)')
-    @CommandArgument('--project',
-                     required=True,
-                     help='Project to use for creating tasks. Example: --project=mozilla-central')
-    @CommandArgument('--level',
-                     required=True,
-                     help='SCM level of this repository')
-    @CommandArgument('--force-run',
-                     required=False,
-                     help='If given, force this cronjob to run regardless of time, '
-                     'and run no others')
-    @CommandArgument('--no-create',
-                     required=False,
-                     action='store_true',
-                     help='Do not actually create tasks')
-    @CommandArgument('--root', '-r',
-                     required=False,
-                     help="root of the repository to get cron task definitions from")
+                description="Provide a pointer to the new `.cron.yml` handler.")
     def taskgraph_cron(self, **options):
-        """Run the cron task; this task creates zero or more decision tasks.  It is run
-        from the hooks service on a regular basis."""
-        import taskgraph.cron
-        try:
-            self.setup_logging()
-            return taskgraph.cron.taskgraph_cron(options)
-        except Exception:
-            traceback.print_exc()
-            sys.exit(1)
+        print(
+            'Handling of ".cron.yml" files has move to '
+            "https://hg.mozilla.org/ci/ci-admin/file/tip/build-decision."
+        )
+        sys.exit(1)
 
     @SubCommand('taskgraph', 'action-callback',
                 description='Run action callback used by action tasks')