[rabbitmq-discuss] Problem extending code from tutorial #6

[Marek Majkowski]

On Wed, Aug 24, 2011 at 09:32, Marek Majkowski <majek04 at gmail.com> wrote:
> Thanks for the report. It does look like a problem caused
> by a bug in Pika or my misunderstanding how start/stop_consuming
> work.

Yup. I did misuse "stop_consuming". Apparently, it calls
basic.cancel, which was completely not inteded:
https://github.com/pika/pika/blob/v0.9.5/pika/adapters/blocking_connection.py#L287

The fix is here:
https://github.com/rabbitmq/rabbitmq-tutorials/commit/c1b178d9deec664cdf12770c24319c7d12d67efd

Thanks again for the report!

Cheers,
  Marek

> On Wed, Aug 24, 2011 at 02:49, Doug Gorley <doug at gorley.ca> wrote:
>> I'm hoping someone can help he with my RabbitMQ problem; I've got some
>> code based on the tutorial #6 code, and it's not doing what I'm expecting.
>> I tried to create a shell where I can send strings to the server and
>> receive the MD5 digest, but I only ever seem to get the first reply.
>>
>> Here's the source:
>>
>> ##########################################################################
>> # server.py
>>
>> import pika
>> import hashlib
>>
>> connection = pika.BlockingConnection(
>>    pika.ConnectionParameters(host='localhost'))
>>
>> channel = connection.channel()
>> channel.queue_declare(queue='my_request')
>>
>> def on_request(ch, method, props, body):
>>
>>    response = hashlib.md5(body).hexdigest()
>>
>>    print("Received '%r', sending '%r'" % (body, response))
>>
>>    ch.basic_publish(exchange='',
>>                     routing_key=props.reply_to,
>>                     properties=pika.BasicProperties(correlation_id = \
>>                                                     props.correlation_id),
>>                     body=response)
>>
>>    ch.basic_ack(delivery_tag = method.delivery_tag)
>>
>> channel.basic_qos(prefetch_count=1)
>> channel.basic_consume(on_request, queue='my_request')
>>
>> print " [x] Awaiting requests"
>> channel.start_consuming()
>> ##########################################################################
>>
>> ##########################################################################
>> # client.py
>>
>> import pika
>> import uuid
>>
>> class RabbitClient(object):
>>
>>    def __init__(self):
>>        self.connection = pika.BlockingConnection(
>>            pika.ConnectionParameters(host='localhost'))
>>
>>        self.channel = self.connection.channel()
>>
>>        result = self.channel.queue_declare(exclusive=True)
>>        self.callback_queue = result.method.queue
>>
>>        self.channel.basic_consume(self.on_response, no_ack=True,
>>                                   queue=self.callback_queue)
>>
>>    def on_response(self, ch, method, props, body):
>>        print(" [.] Received correlation ID %r" % (props.correlation_id,))
>>        if self.corr_id == props.correlation_id:
>>            self.response = body
>>            self.channel.stop_consuming()
>>        else:
>>            print(" [~] Correlation IDs do not match")
>>
>>    def call(self, n):
>>        self.corr_id = str(uuid.uuid4())
>>        self.channel.basic_publish(exchange='',
>>                                   routing_key='my_request',
>>                                   properties=pika.BasicProperties(
>>                                         reply_to=self.callback_queue,
>>                                         correlation_id=self.corr_id,
>>                                         ),
>>                                   body=n)
>>        self.channel.start_consuming()
>>        return self.response
>>
>> auth = RabbitClient()
>>
>> while True:
>>    send = raw_input('> ')
>>    if send == 'quit': break
>>    print(" [x] sending '%s'" % (send))
>>    response = auth.call(send)
>>    print(" [^] sent with correlation ID %s" % (auth.corr_id,))
>>    print(" [.] Got %r" % (response,))
>> ##########################################################################
>>
>> Here's the output from the server:
>>
>> ##########################################################################
>>  [x] Awaiting requests
>> Received ''Hello World'', sending ''b10a8db164e0754105b7a99be72e3fe5''
>> Received ''Hello Rabbit'', sending ''5bec01f45b43f6202e84242fcb71b04f''
>> ##########################################################################
>>
>> And here's the output from the server:
>> ##########################################################################
>>> Hello World
>>  [x] sending 'Hello World'
>>  [.] Received correlation ID '1805f131-1fbc-40a3-86fb-2a113b5f9b9a'
>>  [^] sent with correlation ID 1805f131-1fbc-40a3-86fb-2a113b5f9b9a
>>  [.] Got 'b10a8db164e0754105b7a99be72e3fe5'
>>> Hello Rabbit
>>  [x] sending 'Hello Rabbit'
>>  [^] sent with correlation ID fdb089ff-44ea-4b81-885b-be7e0178d5a1
>>  [.] Got 'b10a8db164e0754105b7a99be72e3fe5'
>>> quit
>> ##########################################################################
>>
>> So, my question is, what am I doing wrong that I didn't get the '5bec'
>> response to the second message?
>>
>> Thanks for your help,
>> --
>> Doug Gorley | doug at gorley.ca
>>
>>
>>
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>>
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