[rabbitmq-discuss] Pika: Error when doing a stop_consuming() from a timeout callback

Fri Jul 29 00:04:06 BST 2011

On 29/7/11 24:54, Gavin M. Roy wrote:
>
> On Thursday, July 28, 2011 at 6:45 PM, Christian Haintz wrote:
>
>> Hi,
>>
>> I want to stop the consuming loop of a BlockingConnection after some
>> timeout. I used the following code. Producer is not running because I
>> want to simulate the timeout. Current pika version is used from github.
> I'd not consider the master branch on Pika stable, which is one of the
> reasons I've not tagged 0.9.6. I'd do a pip install of 0.9.5 and see if
> that solves your problem.
>
> Gavin
>

I tried it first with 0.9.5 but that leads to a different error which 
seams to be fixed in the master branch (used the same test code as in 
the previous e-mail):

--------8<--------- snip ----------8<-----------
python pika_test.py
Traceback (most recent call last):
   File "pika_test.py", line 21, in <module>
     channel.start_consuming()
   File 
"build/bdist.macosx-10.6-universal/egg/pika/adapters/blocking_connection.py", 
line 293, in start_consuming
   File 
"build/bdist.macosx-10.6-universal/egg/pika/adapters/blocking_connection.py", 
line 103, in process_data_events
   File 
"build/bdist.macosx-10.6-universal/egg/pika/adapters/blocking_connection.py", 
line 157, in process_timeouts
NameError: global name 'log' is not defined
--------8<------- snip end --------8<-----------

Best Regards,
Christian


>>
>> --------8<--------- snip ----------8<-----------
>> import pika
>> connection = pika.BlockingConnection(pika.ConnectionParameters(
>> host='localhost'))
>>
>> channel = connection.channel()
>>
>> result = channel.queue_declare(exclusive=True)
>> callback_queue = result.method.queue
>>
>> def on_response(self, ch, method, props, body):
>> #do some processing
>> channel.stop_consuming()
>>
>> # normaly i do some publish here but that's not relevant
>> # to reproduce the error
>>
>> channel.basic_consume(on_response, no_ack=True,
>> queue=callback_queue)
>>
>> def panic():
>> channel.stop_consuming()
>>
>> connection.add_timeout(1, panic)
>> channel.start_consuming()
>>
>> --------8<------- snip end --------8<-----------
>>
>> But I get the following error:
>>
>> --------8<--------- snip ----------8<-----------
>> $ python pika_test.py
>> /Users/christian/devel/pika/pika/callback.py:69: UserWarning:
>> CallbackManager.add: Duplicate callback found for "1:Basic.CancelOk"
>> (self.__class__.__name__, prefix, key))
>> Traceback (most recent call last):
>> File "pika_test.py", line 21, in <module>
>> channel.start_consuming()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 307, in start_consuming
>> self.transport.connection.process_data_events()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 104, in process_data_events
>> self.process_timeouts()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 164, in process_timeouts
>> self._timeouts[timeout_id]['handler']()
>> File "pika_test.py", line 18, in panic
>> channel.stop_consuming()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 318, in stop_consuming
>> self.basic_cancel(consumer_tag)
>> File "/Users/christian/devel/pika/pika/channel.py", line 333, in
>> basic_cancel
>> self._on_cancel_ok, [spec.Basic.CancelOk])
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 220, in rpc
>> self.send_method(method, None, wait)
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 249, in send_method
>> self.connection.process_data_events()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 104, in process_data_events
>> self.process_timeouts()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 164, in process_timeouts
>> self._timeouts[timeout_id]['handler']()
>> File "pika_test.py", line 18, in panic
>> channel.stop_consuming()
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 318, in stop_consuming
>> self.basic_cancel(consumer_tag)
>> File "/Users/christian/devel/pika/pika/channel.py", line 333, in
>> basic_cancel
>> self._on_cancel_ok, [spec.Basic.CancelOk])
>> File
>> "/Users/christian/devel/pika/pika/adapters/blocking_connection.py", line
>> 209, in rpc
>> self._on_rpc_complete)
>> TypeError: 'NoneType' object is not iterable
>>
>>
>> What I am doing wrong? Are the timeout callbacks not capable of stopping
>> the consumer?
>>
>>
>> Regards,
>> Christian
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