dev-notes

RabitMQ

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Hello World Program

Here we are using pika python client. You can pick anyone as per your application.

Find the list of clients here

Prerequisites

1. RabbitMQ is installed and is running on localhost. You can simply do this by running docker image :

   docker run -it --rm --name rabbitmq -p 5672:5672 -p 15672:15672 rabbitmq:3.12-management
   

2. Pika Client

   pip install pika --upgrade
   

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The Program:

Producer Program - sender.py

import pika

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

# INFO: this connects to a broker on the local machine(localhost)

# Creating hello queue

channel.queue_declare(queue="hello")

# INFO: message needs to go through the exchange
# exhange specify exactly to which queue the message should go
# Thus, The queue name needs to be specified in the routing_key parameter:

channel.basic_publish(
    exchange='',
    routing_key='hello',
    body='Hello World')

print("[x] Sent 'Hello World!")


# Before exiting the program we need to make sure the network buffers were flushed and our message was actually delivered to RabbitMQ. We can do it by gently closing the connection.

connection.close()

Consumer Program - receiver.py

import pika, sys, os


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

    channel.queue_declare(queue='hello')

    # Receiving a message works by subscribing a callback function
    #to a queue  Whenever we receive a message, this callback function is called by the Pika library.

    def callback(ch, method, properties, body):
        print(f" [x] Received {body}")


    channel.basic_consume(queue='hello', on_message_callback=callback, auto_ack=True)
    #finally, we enter a never-ending loop that waits for data and runs callbacks whenever necessary,
    # and catch KeyboardInterrupt during program shutdown.

    print("[*] Waiting for message. To exit  press Ctrl+C")
    channel.start_consuming()

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        print('Interrupted')
        try:
            sys.exit(0)
        except SystemExit:
            os._exit(0)

Running

Run Consumer

python receiver.py

Run Producer

python sender.py

Output

By, Consumer

# => [*] Waiting for messages. To exit press CTRL+C
# => [x] Received 'Hello World!'

Reference

Unravel the secrets of RabbitMQ with our reference to the original RabbitMQ tutorial here.

Conclusion

With this guide, you’ve taken the first step into a world of endless possibilities. Stay tuned for more advanced programs