class EventBusPublisher(object):
def __init__(self, kafka_proxy, config):
self.kafka_proxy = kafka_proxy
self.config = config
self.topic_mappings = config.get('topic_mappings', {})
self.event_bus = EventBusClient()
self.subscriptions = None
def start(self):
log.debug('starting')
self.subscriptions = list()
self._setup_subscriptions(self.topic_mappings)
log.info('started')
return self
def stop(self):
try:
log.debug('stopping-event-bus')
if self.subscriptions:
for subscription in self.subscriptions:
self.event_bus.unsubscribe(subscription)
log.info('stopped-event-bus')
except Exception, e:
log.exception('failed-stopping-event-bus', e=e)
return
def test_unsubscribe(self):
ebc = EventBusClient(EventBus())
sub = ebc.subscribe('news', lambda msg, topic: None)
ebc.unsubscribe(sub)
self.assertEqual(ebc.list_subscribers(), [])
self.assertEqual(ebc.list_subscribers('news'), [])
class EventBusPublisher(object):
def __init__(self, kafka_proxy, config):
self.kafka_proxy = kafka_proxy
self.config = config
self.topic_mappings = config.get('topic_mappings', {})
self.event_bus = EventBusClient()
self.subscriptions = None
def start(self):
log.debug('starting')
self.subscriptions = list()
self._setup_subscriptions(self.topic_mappings)
log.info('started')
return self
def stop(self):
try:
log.debug('stopping-event-bus')
if self.subscriptions:
for subscription in self.subscriptions:
self.event_bus.unsubscribe(subscription)
log.info('stopped-event-bus')
except Exception as e:
log.exception('failed-stopping-event-bus', e=e)
return
def _setup_subscriptions(self, mappings):
for event_bus_topic, mapping in six.iteritems(mappings):
kafka_topic = mapping.get('kafka_topic', None)
if kafka_topic is None:
log.error('no-kafka-topic-in-config',
event_bus_topic=event_bus_topic,
mapping=mapping)
continue
self.subscriptions.append(
self.event_bus.subscribe(
event_bus_topic,
# to avoid Python late-binding to the last registered
# kafka_topic, we force instant binding with the default arg
lambda _, m, k=kafka_topic: self.forward(k, m)))
log.info('event-to-kafka',
kafka_topic=kafka_topic,
event_bus_topic=event_bus_topic)
def forward(self, kafka_topic, msg):
try:
# convert to JSON string if msg is a protobuf msg
if isinstance(msg, Message):
msg = dumps(MessageToDict(msg, True, True))
log.debug('forward-event-bus-publisher')
self.kafka_proxy.send_message(kafka_topic, msg)
except Exception as e:
log.exception('failed-forward-event-bus-publisher', e=e)
def test_wildcard_topic(self):
ebc = EventBusClient(EventBus())
subs = []
wildcard_sub = Mock()
subs.append(ebc.subscribe(re.compile(r'.*'), wildcard_sub))
prefix_sub = Mock()
subs.append(ebc.subscribe(re.compile(r'ham.*'), prefix_sub))
contains_sub = Mock()
subs.append(ebc.subscribe(re.compile(r'.*burg.*'), contains_sub))
ebc.publish('news', 1)
ebc.publish('hamsters', 2)
ebc.publish('hamburgers', 3)
ebc.publish('nonsense', 4)
c = call
self.assertEqual(wildcard_sub.call_count, 4)
wildcard_sub.assert_has_calls([
c('news', 1),
c('hamsters', 2),
c('hamburgers', 3),
c('nonsense', 4)])
self.assertEqual(prefix_sub.call_count, 2)
prefix_sub.assert_has_calls([
c('hamsters', 2),
c('hamburgers', 3)])
self.assertEqual(contains_sub.call_count, 1)
contains_sub.assert_has_calls([c('hamburgers', 3)])
for sub in subs:
ebc.unsubscribe(sub)
self.assertEqual(ebc.list_subscribers(), [])