def subscribe(self, topic: str):
""" Actually sends the subscription request, by picking a broker at random """
logging.info("Trying to discover brokers in the swarm")
brokers = discover(get_current_host_ip(),
service_type=SERVICE_TYPE.TOPIC_BROKER)
# Choose a random broker
subscribe_to = random.choice(brokers)
poll_ctr = 0
while not poll(subscribe_to) and poll_ctr < 5:
subscribe_to = random.choice(Config.DOCKER_BROKER_ADDRESSES)
poll_ctr += 1
logging.info("Subscribing to Host: {0}".format(subscribe_to))
if not poll(subscribe_to):
logging.error("Broker {0} is down".format(subscribe_to))
return False
# The topic to subscribe to
subscribe_topic = topic if topic else self.topic
# Format the url by adding the schema, eg. 'http://' to it
url = add_schema_to_url("{0}/{1}/{2}".format(subscribe_to,
ENDPOINTS.SUBSCRIBE,
subscribe_topic))
logging.info("Calling URL {}".format(url))
response = requests.get(url)
response_json = response.json()
if response_json['brokers']:
self.brokers = response_json['brokers']
logging.info("Active brokers: {0}".format(self.brokers))
if response.status_code == 200:
self.subscriptions[subscribe_topic] = True
else:
self.subscriptions[subscribe_topic] = False
return self.subscriptions[subscribe_topic]
def get_next():
file_path = utils.poll(real_path('processed_votes'))
lines_processed = utils.lines(real_path('processed_votes'))
lines_processing = utils.lines(real_path('processing_votes'))
to_process = PROCESSING_BUFFER_SIZE - lines_processed - lines_processing
process(to_process)
return file_path
def notify(self, subscriber, topic, message):
""" Sends the message to a subscriber """
if not poll(subscriber):
logging.error("Subscriber {0} is down".format(subscriber))
return False
url = "{0}/{1}".format(subscriber, ENDPOINTS.NOTIFY)
cleaned_url = add_schema_to_url(url)
logging.info("Notifying URL: {}".format(cleaned_url))
post_data = {'topic': topic, 'data': message}
logging.info("Message being sent is: {}".format(message))
response = requests.post(cleaned_url, data=post_data)
return response.status_code == 200
def publish(self, message):
""" Publish message to the central broker """
publish_to = Config.BROKER_ADDRESS
# Check if broker is up
if not poll(publish_to):
logging.error("Broker {0} is down".format(publish_to))
return False
url = add_schema_to_url("{0}/{1}/{2}".format(publish_to,
ENDPOINTS.PUBLISH,
self.topic))
logging.info("Publishing to URL {0} : {1}".format(url, message))
resp = requests.post(url, data=message)
return resp
def subscribe(self, topic: str):
""" Subscribe to a topic at the central broker """
if not poll(SUBSCRIBE_TO):
logging.error("Broker {0} is down".format(SUBSCRIBE_TO))
return False
subscribe_topic = topic if topic else self.topic
url = add_schema_to_url("{0}/{1}/{2}".format(SUBSCRIBE_TO, ENDPOINTS.SUBSCRIBE, subscribe_topic))
logging.info("Calling URL {}".format(url))
response = requests.get(url)
if response.status_code == 200:
self.subscriptions[subscribe_topic] = True
else:
self.subscriptions[subscribe_topic] = False
return self.subscriptions[subscribe_topic]