Fanout Exchange

[ouziel-slama]

Hello,

I'am trying to set up a fanout exchange to deliver a message to multiple consumers. I didn't find any example for that. I tried to write something similar to the pika example here https://www.rabbitmq.com/tutorials/tutorial-three-python.html. The code doesn't raise any error, but only the first consumer receives message. Here the relevant code:

Publisher:

self.connection = amqpstorm.Connection(self.host, self.username, self.password)
self.channel = self.connection.channel()
self.channel.exchange.declare(exchange=self.exchange, exchange_type='fanout')
self.channel.queue.declare(self.queue, durable=True)
self.channel.queue.bind(self.queue, exchange=self.exchange)
self.channel.confirm_deliveries()
self.channel.basic.publish(body=body, routing_key=self.queue, mandatory=True, exchange=self.exchange)

Consumer:

self.connection = amqpstorm.Connection(self.host, self.username, self.password)
self.channel = self.connection.channel()
self.channel.exchange.declare(exchange=self.exchange, exchange_type='fanout')
self.channel.queue.declare(self.queue, durable=True)
self.channel.queue.bind(self.queue, exchange=self.exchange)
self.channel.confirm_deliveries()
self.channel.basic.consume(self.queue, no_ack=False)

Is the correct code to set up a fanout exchange ? I tried with no_ack=False and no_ack=True, and different variants of the code above, but I always get the same thing: no error, but only the first consumer receives the message.

Thank you in advance for your help.

[eandersson]

Hey,

If you have multiple consumers consuming from the same queue, only one of them will get the message. You will need to use different queues for each consumer, as an example in the pika example this is done using channel.queue_declare(exclusive=True), but you could simple use different names for the various consumers; e.g. queue1 and queue2.

In amqpstorm you would implement an exclusive queue like this.

result = self.channel.queue.declare(durable=True, exclusive=True)
self.queue = result['queue']

I hope this helps. =]

[ouziel-slama]

Hey,

Ah yeah, got it! Thank you very much for your answer, will try that now!

Best

[eandersson]

No worries. Let me know if you run in to any issues!

[ouziel-slama]

Works very well thank you!