RabbitMQ How to Broadcast to All Consumers

We are going to show you how to broadcast to all consumers using RabbitMQ. This can be achieved using a publish/subscribe model. We also cover this in our RabbitMQ Tutorial.

You are basically going to want to create a fanout exchange. With a fanout exchange the routing key will be ignored. Each consumer will create it’s own temporary queue.

Publisher example:

emit_log.py


import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='logs', exchange_type='fanout')

message = ' '.join(sys.argv[1:]) or "info: Hello World!"
channel.basic_publish(exchange='logs', routing_key='', body=message)
print(" [x] Sent %r" % message)
connection.close()

Subscriber example:

receive_logs.py


import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='logs', exchange_type='fanout')

result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue

channel.queue_bind(exchange='logs', queue=queue_name)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
    print(" [x] %r" % body)

channel.basic_consume(
    queue=queue_name, on_message_callback=callback, auto_ack=True)

channel.start_consuming()

You can basically copy and paste the code examples above. Just change them around to fit the project that you are working on.