I tried it and it yields the same result: The assertion passes, the
exception is None and the error is still being logged.
def done(fut):
print("Done")
assert fut.exception() is None
The "Done" part is printed as before.
On Friday, March 28, 2014 12:22:00 AM UTC+1, Guido van Rossum wrote:
>
> Try calling fut.exception() inside the done() callback.
>
>
> On Thu, Mar 27, 2014 at 4:18 PM, Florian Rüchel
> <[email protected]<javascript:>
> > wrote:
>
>> Oh sorry... No it didn't solve my problem. The assertions all pass and
>> the error messages remain. I also added logging as you recommended, but it
>> only shows that the exception is None.
>>
>>
>> On Friday, March 28, 2014 12:16:26 AM UTC+1, Guido van Rossum wrote:
>>
>>> So does this solve your problem or not? You didn't say...
>>>
>>>
>>> On Thu, Mar 27, 2014 at 4:15 PM, Florian Rüchel <[email protected]>wrote:
>>>
>>>> I modified the code a little, so I make sure it is done and has no
>>>> exception:
>>>>
>>>> def done(fut):
>>>> print("Future is done")
>>>> for task in conn_tasks:
>>>> task.add_done_callback(done)
>>>> done, pending = yield from asyncio.wait(conn_tasks, timeout=5)
>>>> assert not pending
>>>> for task in done:
>>>> assert task.exception() is None
>>>> assert task.result() is None
>>>>
>>>> This executes cleanly, without throwing an exception and prints "Future
>>>> is done" for each connection.
>>>>
>>>> On Friday, March 28, 2014 12:07:41 AM UTC+1, Guido van Rossum wrote:
>>>>
>>>>> 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)
>>>>>
>>>>
>>>
>>>
>>> --
>>> --Guido van Rossum (python.org/~guido)
>>>
>>
>
>
> --
> --Guido van Rossum (python.org/~guido)
>
