Diagnostic info loss or app failure results when connection is closed by broker

[agoragames]

Diagnostic info loss or app failure results when connection is closed by broker

[awestendorf]

Good stuff. The "set to None" is there to help reference counting clean up channels under high load without relying on the garbage collector. I'll work on fixing this.

[awestendorf]

I think a good way to way to solve this would be to restructure the code in a try-finally block and document clearly that the listeners will be able to access the channel attributes at call time but they'll be out of scope after that.

The close listeners are brand new as I needed them to fix a variety of problems in the ChannelPool so please keep writing up bugs for anything associated with them.

  def _closed_cb(self, final_frame=None):
    if final_frame:
      self._connection.send_frame( final_frame )

    try:
      for listener in self._close_listeners:
        listener( self )
    finally:
      self._pending_events = deque()
      self._frame_buffer = deque()

      for protocol_class in self._class_map.values():
        protocol_class._cleanup()

      self._connection = None
      self.channel = None
      self.exchange = None
      self.queue = None
      self.basic = None
      self.tx = None
      self._class_map = None
      self._close_listeners = set()

[vitaly-krugl]

That looks very reasonable. I think that this also needs to be complimented with a small change in Channel class that allows the user to access the ch.closed attribute at any time without crashing. Perhaps something like this:

  @property
  def closed(self):
    return self.channel is None or self.channel.closed


# Usage example
if not ch.closed:
    ch.close()

[vitaly-krugl]

The user would also need to know that their last opportunity to extract close_info is in the close-listener callback. However, in my code, I also wished I could to do something like this from anywhere:

if ch.closed:
    self._logger.error("Channel closed unexpectedly; close_info: %r", ch.close_info)

[awestendorf]

Fixed this in master by moving all channel state into Channel and out of ChannelClass. Will go out with the next release later today.