Extract some boilerplate from the worker and create a base class. Port the diffs worker over to the base.

workers/worker.py

@@ -0,0 +1,53 @@
+import logging
+import json
+
+from threading import Event
+from apscheduler.scheduler import Scheduler
+
+
+logger = logging.getLogger(__name__)
+
+
+class Worker(object):
+  def __init__(self, queue, poll_period_seconds=30, reservation_seconds=300):
+    self._sched = Scheduler()
+    self._poll_period_seconds = poll_period_seconds
+    self._reservation_seconds = reservation_seconds
+    self._stop = Event()
+    self._queue = queue
+
+  def process_queue_item(self, job_details):
+    """ Return True if complete, False if it should be retried. """
+    raise NotImplementedError('Workers must implement run.')
+
+  def poll_queue(self):
+    logger.debug('Getting work item from queue.')
+
+    item = self._queue.get()
+    while item:
+      logger.debug('Queue gave us some work: %s' % item.body)
+
+      job_details = json.loads(item.body)
+
+      if self.process_queue_item(job_details):
+        self._queue.complete(item)
+      else:
+        logger.warning('An error occurred processing request: %s' % item.body)
+        self._queue.incomplete(item)
+
+      item = self._queue.get(processing_time=self._reservation_seconds)
+
+    logger.debug('No more work.')
+
+  def start(self):
+    logger.debug("Scheduling worker.")
+
+    self._sched.start()
+    self._sched.add_interval_job(self.poll_queue,
+                                 seconds=self._poll_period_seconds)
+
+    while not self._stop.wait(1):
+      pass
+
+  def join(self):
+    self._stop.set()