def inner(self, *args, **kwargs):
# abort if these message has already been processed and another event message
# has already been emitted to drive the state machine forward
primary = get_message_dispatched(self.correlation_id,
self.steps,
primary=True)
secondary = get_message_dispatched(self.correlation_id,
self.steps,
primary=False)
dispatched = primary or secondary
if dispatched:
self._queue_error(
ERRORS.DUPLICATE,
'Message has been processed already (%s).' % dispatched)
return
f(self, *args, **kwargs)
# once the message is emitted, we want to make sure the current event is never sent again.
# the approach here is to simply use a cache to set a key like "correlation_id-steps"
primary = set_message_dispatched(self.correlation_id,
self.steps,
self.retries,
primary=True)
secondary = set_message_dispatched(self.correlation_id,
self.steps,
self.retries,
primary=False)
dispatched = primary and secondary # 'and' is correct here. it just triggers an alarm.
if not dispatched:
self._queue_error(
ERRORS.CACHE, 'Unable set message dispatched for idempotency.')
def smoke(self):
correlation_id = uuid.uuid4().hex
# can dispatch
dispatched = aws.set_message_dispatched(correlation_id, 1, 1)
self.assertTrue(dispatched is True)
# is dispatched
dispatched = aws.get_message_dispatched(correlation_id, 1)
self.assertTrue(dispatched == correlation_id + '-1-1')
# can dispatch with timeout
dispatched = aws.set_message_dispatched(correlation_id, 1, 1, timeout=1)
self.assertTrue(dispatched is True)
time.sleep(2)
# is not dispatched after timeout
dispatched = aws.get_message_dispatched(correlation_id, 1)
self.assertTrue(dispatched is None)