Move security notification work into its own method to allow for return values

Fixes #1302
Fixes #1304

test/test_secscan.py

@@ -506,7 +506,7 @@ class TestSecurityScanner(unittest.TestCase):
     # Test with an unknown notification.
     with HTTMock(get_notification, unknown_notification):
       worker = SecurityNotificationWorker(None)
-      self.assertFalse(worker.process_queue_item({
+      self.assertFalse(worker.perform_notification_work({
         'Name': 'unknownnotification'
       }))
 
@@ -517,7 +517,7 @@ class TestSecurityScanner(unittest.TestCase):
 
     with HTTMock(get_notification, delete_notification, unknown_notification):
       worker = SecurityNotificationWorker(None)
-      self.assertTrue(worker.process_queue_item(data))
+      self.assertTrue(worker.perform_notification_work(data))
 
     self.assertEquals(['GET-1', 'GET-2', 'DELETE'], pages_called)
 

workers/queueworker.py

@@ -44,7 +44,11 @@ class QueueWorker(Worker):
     self.add_operation(self.run_watchdog, self._watchdog_period_seconds)
 
   def process_queue_item(self, job_details):
-    """ Return True if complete, False if it should be retried. """
+    """ Processes the work for the given job. If the job fails and should be retried,
+        this method should raise a WorkerUnhealthyException. If the job should be marked
+        as permanently failed, it should raise a JobException. Otherwise, a successful return
+        of this method will remove the job from the queue as completed.
+    """
     raise NotImplementedError('Workers must implement run.')
 
   def watchdog(self):

workers/security_notification_worker.py

@@ -15,6 +15,14 @@ _LAYER_LIMIT = 100 # The number of layers to request on each page.
 
 class SecurityNotificationWorker(QueueWorker):
   def process_queue_item(self, data):
+    self.perform_notification_work(data)
+
+  def perform_notification_work(self, data):
+    """ Performs the work for handling a security notification as referenced by the given data
+        object. Returns True on successful handling, False on non-retryable failure and raises
+        a JobException on retryable failure.
+    """
+
     notification_name = data['Name']
     current_page = data.get('page', None)