Use push updates in Apple TV

[postlund]

Description:

This basically removes the need to poll for device state changes.

Checklist:

If the code communicates with devices, web services, or third-party tools:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.

[mention-bot]

@postlund, thanks for your PR! By analyzing the history of the files in this pull request, we identified @balloob, @fabaff and @rmkraus to be potential reviewers.

[balloob]

Please remove home-assistant-polymer from your changed files.

[postlund]

Ouch, missed that one. Removed now.

[balloob]

I see a mix of async and sync methods being used. Please make sure you annotate methods correctly and don't mix them.

[balloob]

Please add annotation @callback or @asyncio.coroutine (or, if this is not an async method, do not use hass.async_add_job but instead use hass.add_job.

[postlund]

Should be a @callback, yes. It is called as a callback from an async method (think "future"), so everything it performs must be synced with event loop.

[balloob]

Instead of starting this here, consider adding this to async_added_to_hass

@asyncio.coroutine
def async_added_to_hass(self):
    """Called when entity is about to be added to HASS."""
    self._atv.push_updater.start()

[postlund]

Sure!

[balloob]

Are you sure that you should not use asyncio.TimeoutError ?

[postlund]

After some thinking I believe I can remove this altogether. It was some experimenting I worked with first but I don't think it's needed.

[balloob]

Why do an update if you're not changing any of the internal state ?

[postlund]

What, I must have missed something here. It's supposed to reset self._playing. I'll add that, good spotting!

[balloob]

Is this supposed to be run inside a thread?

[postlund]

I do not think so. Doing "stop" is basically cancel on a future and that is not thread-safe, so it must be run in the event loop. So it should be OK?

[pvizeli]

Need to be add as @callback

[balloob]

Are these methods async friendly ? (_set_power_off is marked as an async callback)

[postlund]

Yes, they are from what I have gathered (with same reasoning as earlier regarding canceling a future - start effectively adds a future to the event loop).

[balloob]

hass will be available as self.hass, no need to pass in reference yourself. If push_updater expects hass to be there, only make connection inside async_added_to_hass and you should be good 👍

[postlund]

Ok, cool. Is this a new thing I have missed? I don't recognize async_added_to_hass 😄

[balloob]

Yeah it's new, came in last release :)

[balloob]

Niiice 🐬

[postlund]

Hmm, just pulled from dev and restarted. I get the following error in the log file now:

17-03-02 09:29:38 ERROR (MainThread) [homeassistant.components.media_player] Error while setting up platform apple_tv
Traceback (most recent call last):
  File "/home/pi/home-assistant/homeassistant/helpers/entity_component.py", line 142, in _async_setup_platform
    entity_platform.async_schedule_add_entities, discovery_info
  File "/home/pi/home-assistant/homeassistant/components/media_player/apple_tv.py", line 82, in async_setup_platform
    yield from async_add_entities([entity])
TypeError: 'NoneType' object is not iterable

I have not seen this before and how can that even happen?