On Tue, Aug 17, 2021 at 3:07 PM Niteesh G. S. <niteesh...@gmail.com> wrote:
> > > On Tue, Aug 17, 2021 at 10:21 AM John Snow <js...@redhat.com> wrote: > >> >> >> On Fri, Jul 30, 2021 at 4:19 PM G S Niteesh Babu <niteesh...@gmail.com> >> wrote: >> >> [...] > >> >>> + >>> + >>> class App(QMPClient): >>> - def __init__(self, address: Union[str, Tuple[str, int]]) -> None: >>> + def __init__(self, address: Union[str, Tuple[str, int]], >>> num_retries: int, >>> + retry_delay: Optional[int]) -> None: >>> urwid.register_signal(type(self), UPDATE_MSG) >>> self.window = Window(self) >>> self.address = address >>> self.aloop: Optional[Any] = None # FIXME: Use more concrete >>> type. >>> + self.num_retries = num_retries >>> + self.retry_delay = retry_delay >>> + self.retry: bool = False >>> + self.disconnecting: bool = False >>> >> >> Why is this one needed again ? ... >> > > A race condition occurs in protocol.py line 597 > The reason behind this is there are two disconnect calls initiated. The > first one via kill_app > and the second one via manage_connection when the state is set to > disconnecting by the first call. > One of the calls set's the state to IDLE(protocol.py:584) after it has > finished disconnecting, meanwhile > the second call is somehow in the process of disconnecting and assert the > state to be in DISCONNECTING > in protocol.py:597, which it is not since it has been set to IDLE by the > first call. > > If I don't gaurd against the second call I get the following exception > > ------------------------------------------------------------------------------------------ > Traceback (most recent call last): > File "/home/niteesh/development/qemu/python/.venv/bin/aqmp-tui", line > 33, in <module> > sys.exit(load_entry_point('qemu', 'console_scripts', 'aqmp-tui')()) > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 695, in main > app.run(args.asyncio_debug) > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 444, in run > raise err > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 441, in run > main_loop.run() > File > "/home/niteesh/development/qemu/python/.venv/lib/python3.6/site-packages/urwid/main_loop.py", > line 287, in run > self._run() > File > "/home/niteesh/development/qemu/python/.venv/lib/python3.6/site-packages/urwid/main_loop.py", > line 385, in _run > self.event_loop.run() > File > "/home/niteesh/development/qemu/python/.venv/lib/python3.6/site-packages/urwid/main_loop.py", > line 1494, in run > reraise(*exc_info) > File > "/home/niteesh/development/qemu/python/.venv/lib/python3.6/site-packages/urwid/compat.py", > line 58, in reraise > raise value > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 391, in manage_connection > await self.disconnect() > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 312, in disconnect > raise err > File "/home/niteesh/development/qemu/python/qemu/aqmp/aqmp_tui.py", line > 300, in disconnect > await super().disconnect() > File "/home/niteesh/development/qemu/python/qemu/aqmp/protocol.py", line > 302, in disconnect > await self._wait_disconnect() > File "/home/niteesh/development/qemu/python/qemu/aqmp/protocol.py", line > 583, in _wait_disconnect > self._cleanup() > File "/home/niteesh/development/qemu/python/qemu/aqmp/qmp_client.py", > line 331, in _cleanup > super()._cleanup() > File "/home/niteesh/development/qemu/python/qemu/aqmp/protocol.py", line > 597, in _cleanup > assert self.runstate == Runstate.DISCONNECTING > AssertionError > > ------------------------------------------------------------------------------------------- > Hm, OK. I'm not sure if this is a bug on my part or not yet, I'll investigate. > def add_to_history(self, msg: str, level: Optional[str] = None) -> >>> None: >>> @@ -119,7 +132,7 @@ def _cb_inbound(self, msg: Message) -> Message: >>> LOGGER.info('Error server disconnected before reply') >>> urwid.emit_signal(self, UPDATE_MSG, >>> '{"error": "Server disconnected before >>> reply"}') >>> - self._set_status("Server disconnected") >>> + await self.disconnect() >>> except Exception as err: >>> LOGGER.error('Exception from _send_to_server: %s', str(err)) >>> raise err >>> @@ -136,15 +149,29 @@ def kill_app(self) -> None: >>> create_task(self._kill_app()) >> >> Is this required? I would have hoped that after calling disconnect that >> the state would have again changed to IDLE and you wouldn't need this >> clause here. >> > After you mentioned it I too felt it was redundant. But on removing it the > whole app freezes when trying to exit. > I logged the state after the call to disconnect, instead of being in the > IDLE state, it is still in DISCONNECTING state. > I suspect this results in the constant infinite looping which doesn't give > other coroutines a chance to run and blocks > the event loop thus resulting in the freezing of the app. But I am not > sure why the state isn't changing to IDLE. > Hmm ... That may well be a bug in AQMP then. I will investigate.