Fix Nest async from sync (#15997)

homeassistant/components/nest/__init__.py

@@ -4,10 +4,10 @@ Support for Nest devices.
 For more details about this component, please refer to the documentation at
 https://home-assistant.io/components/nest/
 """
-from concurrent.futures import ThreadPoolExecutor
 import logging
 import socket
 from datetime import datetime, timedelta
+import threading
 
 import voluptuous as vol
 
@@ -16,8 +16,9 @@ from homeassistant.const import (
     CONF_STRUCTURE, CONF_FILENAME, CONF_BINARY_SENSORS, CONF_SENSORS,
     CONF_MONITORED_CONDITIONS,
     EVENT_HOMEASSISTANT_START, EVENT_HOMEASSISTANT_STOP)
+from homeassistant.core import callback
 from homeassistant.helpers import config_validation as cv
-from homeassistant.helpers.dispatcher import async_dispatcher_send, \
+from homeassistant.helpers.dispatcher import dispatcher_send, \
     async_dispatcher_connect
 from homeassistant.helpers.entity import Entity
 
@@ -71,24 +72,25 @@ CONFIG_SCHEMA = vol.Schema({
 }, extra=vol.ALLOW_EXTRA)
 
 
-async def async_nest_update_event_broker(hass, nest):
+def nest_update_event_broker(hass, nest):
     """
     Dispatch SIGNAL_NEST_UPDATE to devices when nest stream API received data.
 
-    nest.update_event.wait will block the thread in most of time,
-    so specific an executor to save default thread pool.
+    Runs in its own thread.
     """
     _LOGGER.debug("listening nest.update_event")
-    with ThreadPoolExecutor(max_workers=1) as executor:
-        while True:
-            await hass.loop.run_in_executor(executor, nest.update_event.wait)
-            if hass.is_running:
-                nest.update_event.clear()
-                _LOGGER.debug("dispatching nest data update")
-                async_dispatcher_send(hass, SIGNAL_NEST_UPDATE)
-            else:
-                _LOGGER.debug("stop listening nest.update_event")
-                return
+
+    while hass.is_running:
+        nest.update_event.wait()
+
+        if not hass.is_running:
+            break
+
+        nest.update_event.clear()
+        _LOGGER.debug("dispatching nest data update")
+        dispatcher_send(hass, SIGNAL_NEST_UPDATE)
+
+    _LOGGER.debug("stop listening nest.update_event")
 
 
 async def async_setup(hass, config):
@@ -167,16 +169,21 @@ async def async_setup_entry(hass, entry):
     hass.services.async_register(
         DOMAIN, 'set_mode', set_mode, schema=AWAY_SCHEMA)
 
+    @callback
     def start_up(event):
         """Start Nest update event listener."""
-        hass.async_add_job(async_nest_update_event_broker, hass, nest)
+        threading.Thread(
+            name='Nest update listener',
+            target=nest_update_event_broker,
+            args=(hass, nest)
+        ).start()
 
     hass.bus.async_listen_once(EVENT_HOMEASSISTANT_START, start_up)
 
+    @callback
     def shut_down(event):
         """Stop Nest update event listener."""
-        if nest:
-            nest.update_event.set()
+        nest.update_event.set()
 
     hass.bus.async_listen_once(EVENT_HOMEASSISTANT_STOP, shut_down)