EntityComponent to retry platforms that are not ready yet (#8209)

* Add PlatformNotReady Exception

* lint

* Remove cap, adjust algorithm

homeassistant/core.py

@@ -240,7 +240,7 @@ class HomeAssistant(object):
         target: target to call.
         args: parameters for method to call.
         """
-        if is_callback(target):
+        if not asyncio.iscoroutine(target) and is_callback(target):
             target(*args)
         else:
             self.async_add_job(target, *args)

homeassistant/exceptions.py

@@ -26,3 +26,9 @@ class TemplateError(HomeAssistantError):
         """Init the error."""
         super().__init__('{}: {}'.format(exception.__class__.__name__,
                                          exception))
+
+
+class PlatformNotReady(HomeAssistantError):
+    """Error to indicate that platform is not ready."""
+
+    pass

homeassistant/helpers/entity_component.py

@@ -8,19 +8,22 @@ from homeassistant.const import (
     ATTR_ENTITY_ID, CONF_SCAN_INTERVAL, CONF_ENTITY_NAMESPACE,
     DEVICE_DEFAULT_NAME)
 from homeassistant.core import callback, valid_entity_id
-from homeassistant.exceptions import HomeAssistantError
+from homeassistant.exceptions import HomeAssistantError, PlatformNotReady
 from homeassistant.loader import get_component
 from homeassistant.helpers import config_per_platform, discovery
 from homeassistant.helpers.entity import async_generate_entity_id
-from homeassistant.helpers.event import async_track_time_interval
+from homeassistant.helpers.event import (
+    async_track_time_interval, async_track_point_in_time)
 from homeassistant.helpers.service import extract_entity_ids
 from homeassistant.util import slugify
 from homeassistant.util.async import (
     run_callback_threadsafe, run_coroutine_threadsafe)
+import homeassistant.util.dt as dt_util
 
 DEFAULT_SCAN_INTERVAL = timedelta(seconds=15)
 SLOW_SETUP_WARNING = 10
 SLOW_SETUP_MAX_WAIT = 60
+PLATFORM_NOT_READY_RETRIES = 10
 
 
 class EntityComponent(object):
@@ -113,7 +116,7 @@ class EntityComponent(object):
 
     @asyncio.coroutine
     def _async_setup_platform(self, platform_type, platform_config,
-                              discovery_info=None):
+                              discovery_info=None, tries=0):
         """Set up a platform for this component.
 
         This method must be run in the event loop.
@@ -162,6 +165,16 @@ class EntityComponent(object):
             yield from entity_platform.async_block_entities_done()
             self.hass.config.components.add(
                 '{}.{}'.format(self.domain, platform_type))
+        except PlatformNotReady:
+            tries += 1
+            wait_time = min(tries, 6) * 30
+            self.logger.warning(
+                'Platform %s not ready yet. Retrying in %d seconds.',
+                platform_type, wait_time)
+            async_track_point_in_time(
+                self.hass, self._async_setup_platform(
+                    platform_type, platform_config, discovery_info, tries),
+                dt_util.utcnow() + timedelta(seconds=wait_time))
         except asyncio.TimeoutError:
             self.logger.error(
                 "Setup of platform %s is taking longer than %s seconds."

tests/helpers/test_entity_component.py

@@ -9,6 +9,7 @@ from datetime import timedelta
 
 import homeassistant.core as ha
 import homeassistant.loader as loader
+from homeassistant.exceptions import PlatformNotReady
 from homeassistant.components import group
 from homeassistant.helpers.entity import Entity, generate_entity_id
 from homeassistant.helpers.entity_component import (
@@ -21,7 +22,7 @@ import homeassistant.util.dt as dt_util
 
 from tests.common import (
     get_test_home_assistant, MockPlatform, MockModule, fire_time_changed,
-    mock_coro)
+    mock_coro, async_fire_time_changed)
 
 _LOGGER = logging.getLogger(__name__)
 DOMAIN = "test_domain"
@@ -533,3 +534,47 @@ def test_extract_from_service_available_device(hass):
     assert ['test_domain.test_3'] == \
         sorted(ent.entity_id for ent in
                component.async_extract_from_service(call_2))
+
+
+@asyncio.coroutine
+def test_platform_not_ready(hass):
+    """Test that we retry when platform not ready."""
+    platform1_setup = Mock(side_effect=[PlatformNotReady, PlatformNotReady,
+                                        None])
+    loader.set_component('test_domain.mod1', MockPlatform(platform1_setup))
+
+    component = EntityComponent(_LOGGER, DOMAIN, hass)
+
+    yield from component.async_setup({
+        DOMAIN: {
+            'platform': 'mod1'
+        }
+    })
+
+    assert len(platform1_setup.mock_calls) == 1
+    assert 'test_domain.mod1' not in hass.config.components
+
+    utcnow = dt_util.utcnow()
+
+    with patch('homeassistant.util.dt.utcnow', return_value=utcnow):
+        # Should not trigger attempt 2
+        async_fire_time_changed(hass, utcnow + timedelta(seconds=29))
+        yield from hass.async_block_till_done()
+        assert len(platform1_setup.mock_calls) == 1
+
+        # Should trigger attempt 2
+        async_fire_time_changed(hass, utcnow + timedelta(seconds=30))
+        yield from hass.async_block_till_done()
+        assert len(platform1_setup.mock_calls) == 2
+        assert 'test_domain.mod1' not in hass.config.components
+
+        # This should not trigger attempt 3
+        async_fire_time_changed(hass, utcnow + timedelta(seconds=59))
+        yield from hass.async_block_till_done()
+        assert len(platform1_setup.mock_calls) == 2
+
+        # Trigger attempt 3, which succeeds
+        async_fire_time_changed(hass, utcnow + timedelta(seconds=60))
+        yield from hass.async_block_till_done()
+        assert len(platform1_setup.mock_calls) == 3
+        assert 'test_domain.mod1' in hass.config.components