AlreadyCalledError in twisted connection adapter

Hi!

I am having trouble with the following scenario:

from twisted.internet import defer, protocol, task
import pika
import pika.adapters.twisted_connection


@defer.inlineCallbacks
def test_the_issue(reactor):
    host = "192.168.8.8"
    port = 5672
    client_creator = protocol.ClientCreator(
        reactor,
        pika.adapters.twisted_connection.TwistedProtocolConnection,
        pika.ConnectionParameters(
            host=host,
            port=port,
            virtual_host="/",
            credentials=pika.PlainCredentials("guest", "guest"),
        ),
    )
    connection = yield client_creator.connectTCP(host, port)
    yield connection.ready
    channel = yield connection.channel()

    d = channel.queue_declare("foo")
    d.cancel()
    try:
        yield d
    except defer.CancelledError:
        pass

    yield channel.close()
    yield connection.close()


if __name__ == "__main__":
    task.react(test_the_issue)

It fails every time:

  File "C:\Python27\lib\site-packages\twisted\internet\selectreactor.py", line 149, in _doReadOrWrite
    why = getattr(selectable, method)()
  File "C:\Python27\lib\site-packages\twisted\internet\tcp.py", line 243, in doRead
    return self._dataReceived(data)
  File "C:\Python27\lib\site-packages\twisted\internet\tcp.py", line 249, in _dataReceived
    rval = self.protocol.dataReceived(data)
  File "C:\Python27\lib\site-packages\pika\adapters\twisted_connection.py", line 1209, in dataReceived
    self._impl.data_received(data)
  File "C:\Python27\lib\site-packages\pika\adapters\twisted_connection.py", line 1143, in data_received
    self._on_data_available(data)
  File "C:\Python27\lib\site-packages\pika\connection.py", line 1952, in _on_data_available
    self._process_frame(frame_value)
  File "C:\Python27\lib\site-packages\pika\connection.py", line 2105, in _process_frame
    if self._process_callbacks(frame_value):
  File "C:\Python27\lib\site-packages\pika\connection.py", line 2086, in _process_callbacks
    frame_value)  # Args
  File "C:\Python27\lib\site-packages\pika\callback.py", line 60, in wrapper
    return function(*tuple(args), **kwargs)
  File "C:\Python27\lib\site-packages\pika\callback.py", line 92, in wrapper
    return function(*args, **kwargs)
  File "C:\Python27\lib\site-packages\pika\callback.py", line 233, in process
    callback(*args, **keywords)
  File "C:\Python27\lib\site-packages\pika\channel.py", line 1121, in _on_closeok
    self._transition_to_closed()
  File "C:\Python27\lib\site-packages\pika\channel.py", line 1055, in _transition_to_closed
    self, self, self._closing_reason)
  File "C:\Python27\lib\site-packages\pika\callback.py", line 60, in wrapper
    return function(*tuple(args), **kwargs)
  File "C:\Python27\lib\site-packages\pika\callback.py", line 92, in wrapper
    return function(*args, **kwargs)
  File "C:\Python27\lib\site-packages\pika\callback.py", line 233, in process
    callback(*args, **keywords)
  File "C:\Python27\lib\site-packages\pika\adapters\twisted_connection.py", line 136, in _on_channel_closed
    d.errback(self._closed)
  File "C:\Python27\lib\site-packages\twisted\internet\defer.py", line 501, in errback
    self._startRunCallbacks(fail)
  File "C:\Python27\lib\site-packages\twisted\internet\defer.py", line 560, in _startRunCallbacks
    raise AlreadyCalledError(extra)

Full log with debug messages from pika

Using pika 1.1.0, twisted 19.10.0 and python 2.7.14.

[abompard]

OK, I see where this comes from, and indeed cancelling those deferreds is not supported at the moment. I can make Pika ignore the error, but maybe we can do better. @lukebakken is there a way in Pika to cancel a call that has been made? Say I’m calling queue_declare and the server is taking too long to respond, as a client can I cancel it? If we can’t tell the server to cancel the operation, maybe as a client we can remove the call from the RPC buffer and not wait for the replies? I’m not sure what’s best to do.

[lukebakken]

I will investigate this before the next major release, thank you!