Pubsub Pattern

• Sending same message to different consumers.
• User creates new account for themselves in our website, and we have an auditing service, and a promotion service which will send an email to the newcomers.
• Producer just wants to publish the message once and then we wanna broadcast the message.
  • To do this we need to use fanout exchange type.
• RabbitMQ will not duplicate the message, so no need to worry about memory footprint.

[!TIP]

You do not need to declare those queues upfront. We can use what’s known as temporary queues which will be deleted automatically once the connection is closed:

queue = channel.queue_declare('', exclusive=True)

How to Start This Example

1. cd docs/rabbitmq.
2. uv venv .venv.
3. source .venv/bin/activate.
4. uv install --requirements ./requirements.txt.
5. Open 3 terminal sessions and cd to the same path
6. Execute the following commands now:
   1. python src/pubsub/auditing-service.py.
   2. python src/pubsub/promotion-service.py.
   3. python src/pubsub/producer.py.