Xiaomi Gateway discovery isn't handling network outages well

[papaiatis]

Home Assistant release (hass --version): 0.60.0

Python release (python3 --version): 3.4.2

Component/platform: xiaomi_aqara

Description of problem: In case of network is unreachable Xiaomi Gateway discovery throws an exception (OSError: [Errno 101] Network is unreachable) and stops discovering devices. This happens at me in case of a power outage and after power comes back HASS is booting up faster than my router is able to finish setting up the local network.

Expected: I expect this component to better handle any exception and keep continuing device discovery.

Traceback (if applicable):

Error during setup of component xiaomi_aqara
Traceback (most recent call last):
File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/setup.py", line 193, in _async_setup_component
component.setup, hass, processed_config)
File "/usr/lib/python3.4/asyncio/futures.py", line 388, in __iter__
yield self # This tells Task to wait for completion.
File "/usr/lib/python3.4/asyncio/tasks.py", line 286, in _wakeup
value = future.result()
File "/usr/lib/python3.4/asyncio/futures.py", line 277, in result
raise self._exception
File "/usr/lib/python3.4/concurrent/futures/thread.py", line 54, in run
result = self.fn(*self.args, **self.kwargs)
File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/components/xiaomi_aqara.py", line 115, in setup
xiaomi.discover_gateways()
File "/srv/homeassistant/lib/python3.4/site-packages/PyXiaomiGateway/__init__.py", line 70, in discover_gateways
(self.MULTICAST_ADDRESS, self.GATEWAY_DISCOVERY_PORT))

Additional info:
I managed to fix this issue in home-assistant/homeassistant/components/xiaomi_aqara.py around line 113 where the discovery happens in a for loop. What I did is to encapsulate the xiaomi.discover_gateways() call in a try..except block as follows:

    for k in range(discovery_retry):
        _LOGGER.info('Discovering Xiaomi Gateways (Try %s)', k + 1)
        try:
            xiaomi.discover_gateways()
            if len(xiaomi.gateways) >= len(gateways):
                break
        except Exception as e:
            _LOGGER.error('Unexpected error occured while discovering Xiaomi Gateways: ' + str(e))
            time.sleep(5)

I believe the sleep() call is necessary because this exception occurs immediately and the loop would finish instantly. Maybe the number of seconds to sleep could be extracted as a config option.
For my case I had to set discovery_retry: 50 so this component has enough time until the network is reachable again.
But IMHO the best would be to wait/sleep until the network is reachable again and not incrementing the retry counter. Without network HASS is useless anyways.

I'm happy to create a pull request with this fix if you accept it.

[syssi]

Please provide a pull request!

[balloobbot]

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Please make sure to update to the latest Home Assistant version and check if that solves the issue. Let us know if that works for you by adding a comment 👍

[balloobbot]

This issue will be auto-closed because there hasn't been any activity for a few months. Feel free to open a new one if you still experience this problem 👍