Rabbitmq Acking in multiple consumers

Question

I have a queue on which multiple consumers are working in round robin fashion.

Delivery_tag is used to ack messages once consumer is done with its processing. But multiple consumers are setting same delivery_tag, though the message on which they are working are different.

As a result of which when acking is done , I am getting precondition failed.

Could anyone advice what I am doing wrong?

This is the consumer code.I got it from this link:

http://blogs.digitar.com/jjww/2009/01/rabbits-and-warrens/

from amqplib import client_0_8 as amqp

conn = amqp.Connection(host="localhost:5672", userid="guest", password="guest", virtual_host="/", insist=False)
chan = conn.channel()

chan.queue_declare(queue="po_box", durable=True, exclusive=False, auto_delete=False)
chan.exchange_declare(exchange="sorting_room", type="direct", durable=True, auto_delete=False,)

chan.queue_bind(queue="po_box", exchange="sorting_room", routing_key="jason")

def recv_callback(msg):
    print 'Received: ' + msg.body + ' from channel #' + str(msg.channel.channel_id)

chan.basic_consume(queue='po_box', no_ack=True, callback=recv_callback, consumer_tag="testtag")
while True:
    chan.wait()
chan.basic_cancel("testtag")


chan.close()
conn.close()

Answer 1

This is the consumer code.I got it from this link.

http://blogs.digitar.com/jjww/2009/01/rabbits-and-warrens/

from amqplib import client_0_8 as amqp

conn = amqp.Connection(host="localhost:5672", userid="guest", password="guest", virtual_host="/", insist=False)
chan = conn.channel()

chan.queue_declare(queue="po_box", durable=True, exclusive=False, auto_delete=False)
chan.exchange_declare(exchange="sorting_room", type="direct", durable=True, auto_delete=False,)

chan.queue_bind(queue="po_box", exchange="sorting_room", routing_key="jason")

def recv_callback(msg):
    print 'Received: ' + msg.body + ' from channel #' + str(msg.channel.channel_id)

chan.basic_consume(queue='po_box', no_ack=True, callback=recv_callback, consumer_tag="testtag")
while True:
    chan.wait()
chan.basic_cancel("testtag")


chan.close()
conn.close()