AIOHTTP ConnectionResetError On Camera Close after 3.3.0

[mezz64]

Home Assistant release with the issue:

Latest Dev Docker Build - 6/10/18

Last working Home Assistant release (if known):
Any build prior to bumping aiohttp to version 3.3.0.

Operating environment (Hass.io/Docker/Windows/etc.):

Docker

Component/platform:

Main mjpeg camera platform and proxy camera platform were tested.

Description of problem:
On closing a stream from the mjpeg camera platform the below error is generated in the log. Functionality is as intended however with no odd behavior. The proxy platform is a little more troublesome in that the same error gets generated constantly multiple times per second when it is active.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

Traceback (if applicable):

2018-06-10 22:04:53 ERROR (MainThread) [aiohttp.server] Unhandled exception
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/aiohttp/web_protocol.py", line 398, in start
    await resp.prepare(request)
  File "/usr/local/lib/python3.6/site-packages/aiohttp/web_response.py", line 300, in prepare
    return await self._start(request)
  File "/usr/local/lib/python3.6/site-packages/aiohttp/web_response.py", line 605, in _start
    return await super()._start(request)
  File "/usr/local/lib/python3.6/site-packages/aiohttp/web_response.py", line 367, in _start
    await writer.write_headers(status_line, headers)
  File "/usr/local/lib/python3.6/site-packages/aiohttp/http_writer.py", line 100, in write_headers
    self._write(buf)
  File "/usr/local/lib/python3.6/site-packages/aiohttp/http_writer.py", line 57, in _write
    raise ConnectionResetError('Cannot write to closing transport')
ConnectionResetError: Cannot write to closing transport

Additional information:

[awarecan]

aio-libs/aiohttp#2499 Add an exception using asyncio.CancelledError
aio-libs/aiohttp#2646 Change exception type to ConnectionResetError (released in aiohttp 3.3.0)

Current aiohttp_client swallowed asyncio.CancelledError, but not ConnectionResetError

https://github.com/home-assistant/home-assistant/blob/722c27f1e2f83e723070e1aff9c826fd78c98f6a/homeassistant/helpers/aiohttp_client.py#L125-L127

To resolve it in root, we should check if response is closing before write to it.

[awarecan]

OK, I can reproduce it by just use demo camera, now I can verify my fix.

Here is the reproduced error log on demo camera. Click to demo camera card to open more-info window watch the stream, then close the window. Got following logs:

2018-06-17 11:30:00 INFO (MainThread) [homeassistant.components.http.view] Serving /api/camera_proxy_stream/camera.demo_camera to 127.0.0.1 (auth: False)
2018-06-17 11:30:05 DEBUG (MainThread) [homeassistant.components.camera] Stream closed by frontend.
2018-06-17 11:30:05 ERROR (MainThread) [aiohttp.server] Unhandled exception
Traceback (most recent call last):
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/web_protocol.py", line 398, in start
    await resp.prepare(request)
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/web_response.py", line 300, in prepare
    return await self._start(request)
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/web_response.py", line 605, in _start
    return await super()._start(request)
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/web_response.py", line 367, in _start
    await writer.write_headers(status_line, headers)
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/http_writer.py", line 100, in write_headers
    self._write(buf)
  File "/home/jason/ha/home-assistant/venv/lib/python3.6/site-packages/aiohttp-3.3.0-py3.6-linux-x86_64.egg/aiohttp/http_writer.py", line 57, in _write
    raise ConnectionResetError('Cannot write to closing transport')
ConnectionResetError: Cannot write to closing transport

[mezz64]

Thanks for looking into this. I'll try to find some time to test this fix tonight.