Looks to me like you're never asking for the result of those Futures you're
passing to asyncio.wait(). It waits until the Futures are complete, but it
doesn't inspect whether they have errors. You need something like
for task in done:
if task.exception(): ...log it...
On Thu, Mar 27, 2014 at 3:19 PM, Florian Rüchel
<[email protected]>wrote:
> I can post the code, I just thought it might be too much. However, I'll
> just post the relevant section. Contrary to multithreaded programming here
> most of the times the local section is enough (I love asyncio :))
>
> Anyways here is the main function:
>
> try:
> self.event_loop.run_forever()
> except KeyboardInterrupt:
> exit_main_loop()
> finally:
> print("Running shutdown cleanup")
> collector.cancel()
>
> @asyncio.coroutine
> def shutdown():
> yield from self.connection_pool.close()
> self.event_loop.run_until_complete(shutdown())
> self.event_loop.close()
>
> And the close method:
>
> @asyncio.coroutine
> def close(self):
> try:
> if self.returned_connections:
> msg = ("Not all connections were returned: %s"
> % self.returned_connections)
> log.error(msg)
> raise ValueError(msg)
> finally:
> conn_tasks = [asyncio.Task(conn.disconnect())
> for conn in self.all_connections]
> done, pending = yield from asyncio.wait(conn_tasks, timeout=5)
> assert not pending
>
> Relevant is the finally part: I wrap each connection in a task and wait
> for them together. Removing the timeout did not help (I didn't expect it
> would, no exception is raised).
>
> Per existing connection (up to 10) a message is produced:
>
> 2014-03-27 23:11:58,143 ERROR[asyncio] Coroutine 'disconnect' defined at
> /path/to/library/connection.py:109 was never yielded from
>
> I have made sure that the amount of logging messages matches exactly the
> number of connections created (by counting the logging messages inside
> connection's __init__ function). In a very simple case there was only one
> connection, so only one error entry and only one log entry for a created
> connection.
>
> Hope this additional information helps uncover the issue. Thanks for the
> response.
>
> On Thursday, March 27, 2014 10:23:10 AM UTC+1, Florian Rüchel wrote:
>>
>> Hi everyone,
>>
>> I currently have a problem I cannot figure out. My code is running
>> perfectly fine, but when using "PYTHONASYNCIODEBUG=1" it reports that a
>> function was never yielded from per instance of that class I have. The
>> problem is I cannot create an example that replicates the issue and the
>> application is fairly large so maybe someone can give a hint on where I
>> might go looking. The function in question is a method of a connection
>> class. The class manages a TCP connection that has to send an init and a
>> disconnect request. It is the disconnect method that is reported as never
>> yielded from. I have log entries that prove that this function was actually
>> run and I have tried wrapping it in asyncio.Task and asyncio.async and I
>> also had a wrapping coroutine that *was *called and an explicit "yield
>> from connection.disconnect()" statement.
>>
>> In all three cases the proper log entries were written and the server got
>> the disconnect request, so I know it was properly executed. Now I am
>> wondering if I have a bug in my application that is hidden somewhere
>> between the layers that is repsonsible for this message. Or is it possible
>> to trigger this error message even though the function was properly called?
>>
>> I'd also like to note that this is *the only* method where this happens,
>> all other methods on all other classes are never reported as problematic.I
>> have checked the method against others but I cannot find any difference at
>> all: They are called with yield from or as tasks, they all use other
>> coroutines (the connect and disconnect method actually both use *yield
>> from self.talk(...)*) and they are all properly decorated.
>>
>> I'm sorry I cannot provide any code examples, but since I am unable to
>> replicate the issue in a small sample, I fear I need further guidance on
>> where to look for the issue.
>>
>> Many thanks in advance and Regards,
>> Florian
>>
>
--
--Guido van Rossum (python.org/~guido)
