Report counts of Tasks created by name.

Summary: This is a cheap way to track task creation for monitoring.

Test Plan: Ran unit.

Reviewers: jukka

Reviewed By: jukka

Subscribers: changesbot, wwu

Differential Revision: https://tails.corp.dropbox.com/D94291

changes/queue/task.py

@@ -7,7 +7,7 @@
 from threading import local, Lock
 from uuid import uuid4
 
-from changes.config import db, queue
+from changes.config import db, queue, statsreporter
 from changes.constants import Result, Status
 from changes.db.utils import get_or_create
 from changes.models import Task
@@ -302,6 +302,9 @@ def delay_if_needed(self, **kwargs):
                 countdown=CONTINUE_COUNTDOWN,
             )
 
+        if created:
+            self._report_created()
+
     def delay(self, **kwargs):
         """
         Enqueue this task.
@@ -335,6 +338,9 @@ def delay(self, **kwargs):
 
         db.session.commit()
 
+        if created:
+            self._report_created()
+
         queue.delay(
             self.task_name,
             kwargs=kwargs,
@@ -400,6 +406,10 @@ def verify_all_children(self):
 
         return status
 
+    def _report_created(self):
+        """Reports to monitoring that a new Task was created."""
+        statsreporter.stats().incr('new_task_created_' + self.task_name)
+
 
 # bind to a decorator-like naming scheme
 def tracked_task(func=None, **kwargs):