weatherkit: use stale data for up to an hour if updates fail

homeassistant/components/weatherkit/coordinator.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import timedelta
+from datetime import datetime, timedelta
 
 from apple_weatherkit import DataSetType
 from apple_weatherkit.client import WeatherKitApiClient, WeatherKitApiClientError
@@ -20,12 +20,15 @@
     DataSetType.HOURLY_FORECAST,
 ]
 
+STALE_DATA_THRESHOLD = timedelta(hours=1)
+
 
 class WeatherKitDataUpdateCoordinator(DataUpdateCoordinator):
     """Class to manage fetching data from the API."""
 
     config_entry: ConfigEntry
     supported_data_sets: list[DataSetType] | None = None
+    last_updated_at: datetime | None = None
 
     def __init__(
         self,
@@ -62,10 +65,20 @@ async def _async_update_data(self):
             if not self.supported_data_sets:
                 await self.update_supported_data_sets()
 
-            return await self.client.get_weather_data(
+            updated_data = await self.client.get_weather_data(
                 self.config_entry.data[CONF_LATITUDE],
                 self.config_entry.data[CONF_LONGITUDE],
                 self.supported_data_sets,
             )
         except WeatherKitApiClientError as exception:
-            raise UpdateFailed(exception) from exception
+            if self.data is None or (
+                self.last_updated_at is not None
+                and datetime.now() - self.last_updated_at > STALE_DATA_THRESHOLD
+            ):
+                raise UpdateFailed(exception) from exception
+
+            LOGGER.debug("Using stale data because update failed: %s", exception)
+            return self.data
+        else:
+            self.last_updated_at = datetime.now()
+            return updated_data

tests/components/weatherkit/test_coordinator.py

@@ -1,9 +1,10 @@
 """Test WeatherKit data coordinator."""
 
-from datetime import timedelta
+from datetime import datetime, timedelta
 from unittest.mock import patch
 
 from apple_weatherkit.client import WeatherKitApiClientError
+from freezegun import freeze_time
 
 from homeassistant.const import STATE_UNAVAILABLE
 from homeassistant.core import HomeAssistant
@@ -18,6 +19,14 @@ async def test_failed_updates(hass: HomeAssistant) -> None:
     """Test that we properly handle failed updates."""
     await init_integration(hass)
 
+    state = hass.states.get("weather.home")
+    assert state
+    assert state.state != STATE_UNAVAILABLE
+
+    initial_state = state.state
+
+    # Expect stale data to be used before one hour
+
     with patch(
         "homeassistant.components.weatherkit.WeatherKitApiClient.get_weather_data",
         side_effect=WeatherKitApiClientError,
@@ -28,6 +37,25 @@ async def test_failed_updates(hass: HomeAssistant) -> None:
         )
         await hass.async_block_till_done()
 
+    state = hass.states.get("weather.home")
+    assert state
+    assert state.state == initial_state
+
+    # Expect state to be unavailable after one hour
+
+    with (
+        patch(
+            "homeassistant.components.weatherkit.WeatherKitApiClient.get_weather_data",
+            side_effect=WeatherKitApiClientError,
+        ),
+        freeze_time(datetime.now() + timedelta(hours=1)),
+    ):
+        async_fire_time_changed(
+            hass,
+            utcnow() + timedelta(hours=1),
+        )
+        await hass.async_block_till_done()
+
     state = hass.states.get("weather.home")
     assert state
     assert state.state == STATE_UNAVAILABLE