RuntimeError: Event loop is closed

[CausticD]

Hi,

Using a very simple test code on Python 3.9:

device_manager = TPLinkDeviceManager(username, password)
device_name = "Test"
device = device_manager.find_device(device_name)
if device:
  print(f'Found {device.model_type.name} device: {device.get_alias()}')
  device.toggle()

I get the following output:

Found HS100 device: Test
Exception ignored in: <function _ProactorBasePipeTransport.__del__ at 0x000001846A0AA310>
Traceback (most recent call last):
  File "C:\Python39\lib\asyncio\proactor_events.py", line 116, in __del__
    self.close()
  File "C:\Python39\lib\asyncio\proactor_events.py", line 108, in close
    self._loop.call_soon(self._call_connection_lost, None)
  File "C:\Python39\lib\asyncio\base_events.py", line 746, in call_soon
    self._check_closed()
  File "C:\Python39\lib\asyncio\base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed
Exception ignored in: <function _ProactorBasePipeTransport.__del__ at 0x000001846A0AA310>
Traceback (most recent call last):
  File "C:\Python39\lib\asyncio\proactor_events.py", line 116, in __del__
    self.close()
  File "C:\Python39\lib\asyncio\proactor_events.py", line 108, in close
    self._loop.call_soon(self._call_connection_lost, None)
  File "C:\Python39\lib\asyncio\base_events.py", line 746, in call_soon
    self._check_closed()
  File "C:\Python39\lib\asyncio\base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

The plug toggles fine, but the runtime error is always thrown.

[piekstra]

@CausticD thank you for bringing this to my attention and for the detailed content! I will be taking a look at this today and prioritizing it over feature development as it looks like a bug to me.

[piekstra]

@CausticD I had an HS100 on hand and unfortunately was not able to reproduce this. I was using a fresh install of Python 3.9.4 on Mac OS X. What version of Python 3.9 are you using and on what OS?

[piekstra]

Doing some digging, it looks like this is most likely a Windows-specific Python issue aio-libs/aiohttp#4324

I will see if it makes sense to add in a workaround to this library to silence the exception being thrown as it looks concerning but is actually harmless to the library's functionality.

[piekstra]

@CausticD when you have a moment, and assuming you were running on Windows, could you try running this Python script as a workaround to the issue? https://gist.github.com/piekstra/3b579d8843232d897eca657c1577f5a7

I am not sure if it simply has to be run once on a Windows machine and will then resolve the issue thereafter. Given it is a workaround and the libraries haven't fixed the issue yet in a public release, I would not want to add this to be a default part of this library.

If it successfully silences the exception for you, I will simply mention it in the README.md for this library.

[CausticD]

@piekstra Wow, that was fast! Many thanks. Yup, a brand new 3.9.4 install on Windows and yes that does fix it! However, it seems to be needed every time in my very limited testing.

[piekstra]

@CausticD that's actually good news that it requires it every time! That alleviates a concern I had about building it into the library and potentially causing some sort of permanent change to behaviors on someone's system. I will have a pull request / branch up shortly that I'd like you to test out when you get a chance.

[piekstra]

Alright @CausticD try this out: #32

In theory you should be able to run the same code snippet as in your original post and you won't see the exception.

[CausticD]

@piekstra Yup, that seems good to me. Reverted my change, added yours and still fine.

[piekstra]

@CausticD excellent! I will add it in officially then and cut a release with the fix.