How to count the number of messages in a RabbitMQ queue using Python ?

[Anurag]

I would like to find out the total number of messages in a queue and compare it against a value using Python. How can I do this?

Thanks

[Gavin M. Roy]

With rabbitpy (https://rabbitpy.readthedocs.org):

import rabbitpy

with rabbitpy.Connection('amqp://guest:guest@localhost:15672') as conn:

    with conn.channel() as channel:

        queue = rabbitpy.Queue(channel, 'queue-name')

        print('The queue has {0} messages'.format(len(queue)))

With pika (https://pika.readthedocs.org):

import pika

connection = pika.BlockingConnection()

channel = connection.channel()

response = channel.queue_declare(‘queue-name’, passive=True)

print('The queue has {0} messages'.format(response.message_count))

With requests:

import requests

response = requests.get('http://guest:guest@localhost:15672/api/queues/%2f/queue-name')

data = response.json()

print('The queue has {0} messages'.format(data['messages']))

Regards,

Gavin  

On Wed, Oct 15, 2014 at 4:08 PM, Anurag <anuragpa...@gmail.com> wrote:

I would like to find out the total number of messages in a queue and compare it against a value using Python. How can I do this?

Thanks

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[Michael Klishin]

 On 16 October 2014 at 00:08:33, Anurag (anuragpa...@gmail.com) wrote:
> I would like to find out the total number of messages in a queue
> and compare it against a value using Python. How can I do this?

1. Execute queue.declare (possibly with passive = True) and see message count on
queue.declare-ok.
2. Use HTTP API.

The former is what I'd recommend.
--
MK

Staff Software Engineer, Pivotal/RabbitMQ

[Laing, Michael]

I use python pika and get that from a queue declare ok.

You can also get it from basic get and maybe other places - see http://www.rabbitmq.com/amqp-0-9-1-reference.html and search for message-count.

ml

On Wed, Oct 15, 2014 at 4:08 PM, Anurag <anuragpa...@gmail.com> wrote:

I would like to find out the total number of messages in a queue and compare it against a value using Python. How can I do this?

Thanks

--

[Pythonjunkie]

I am using the following code to print the number of current messages in a queue and the body of the message. 

But instead of getting the current number, I only get the inital number of messages in the queue (Let's say 10)

So rather than printing:

10

"msg1"

9

"msg2"

...

...

1

"msg10"

I get:

10

"msg1"

10

"msg2"

...

...

1

"msg10"

Here is my code.

def create_channel():

credentials = pika.PlainCredentials("guest", "guest")

conn_params = pika.ConnectionParameters("localhost",credentials = credentials)

conn_broker = pika.BlockingConnection(conn_params)

channel = conn_broker.channel()

channel.queue_declare(queue='q1',passive=True)

global count

count = channel.queue_declare(queue='q1',passive=True)

channel.queue_bind(exchange='q', queue='q1', routing_key='q1')

return channel

def consume_run_loop():

channel = create_channel()

def msg_consumer(channel, method, header, body):

a = count.method.message_count

print a

while a:

channel.basic_ack(delivery_tag=method.delivery_tag)

print body

now = time.time()

print "Job Completed in: %s seconds" % round(time.time(), 2)

time.sleep(5)

return

channel.basic_consume( msg_consumer, queue="q1")

consume_run_loop()

How do I print the update the number of messages in the queue?

Thanks

[Michael Klishin]

On 21 October 2014 at 22:20:43, Pythonjunkie (anuragpa...@gmail.com) wrote:
> a = count.method.message_count

I'm not a Python expert but the `count` value seems to be constant. You have to
use a queue.declare  for every delivery.

[Simon MacMullen]

On 21/10/2014 19:32, Michael Klishin wrote:
> You have to use a queue.declare for every delivery.

Although if you're going to do that, you might as well use basic.get
(which will also tell you the number of messages in the queue).

But in general the idea is that you shouldn't have to care how many
messages there are, as a consumer. You just process them as they come in.

Cheers, Simon

[Pythonjunkie]

When I use 'queue_declare' inside my msg_consumer() function, I get the following error:

"KeyError: 'Queue.DeclareOk' "

 

[Michael Klishin]

On 21 October 2014 at 23:06:17, Pythonjunkie (anuragpa...@gmail.com) wrote:
> When I use 'queue_declare' inside my msg_consumer() function,
> I get the following error:
> "KeyError: 'Queue.DeclareOk' "

There should be no reason why queue.declare can't be used inside a delivery handler.
Certainly the protocol allows it.

So check your code, you are trying to get a key that does not exist on a dictionary.

[Pythonjunkie]

But I only get that error when I use 'queue.declare' inside the function

[Michael Klishin]

 On 21 October 2014 at 23:26:46, Pythonjunkie (anuragpa...@gmail.com) wrote:
> But I only get that error when I use 'queue.declare' inside the
> function

This may be a non-intentional client library limitation. There is nothing in RabbitMQ
or the protocol that limits when queue.declare can be used.

As Simon suggested, you either should not care about how many messages there are
in the queue, or consider using basic.get instead, where the response indicates
if there was a message or not.