import pika
from multiprocessing import Pool


def worker(message):
    print(message)


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

    pool = Pool(processes=2)

    def callback(ch, method, properties, body):
        message = body.decode()
        pool.apply_async(worker, (message,))

    channel.basic_consume(
        queue='hello',
        on_message_callback=callback,
    )

    channel.start_consuming()

    pool.close()
    pool.join()


if __name__ == '__main__':
    main()