Wait for Home Assistant Core to start

If sending the WebSocket message to Home Assistant Core to inform it
about the start of a backup fails, we should reject the backup process
entirely. This prevents taking a backup without Home Assistant Core
being aware of it.

As a side effect, this likely prevents situation where Core does not
learn about the backup progress since we also won't be able to send
WebSocket messages about Job progress updates.

.github/workflows/builder.yml

@@ -320,6 +320,15 @@ jobs:
             exit 1
           fi
 
+      - name: Wait for Home Assistant Core to start
+        run: |
+          echo "Waiting for Home Assistant Core to start"
+          timeout 10m ha supervisor logs -f -n 10000 -b 0 | grep -q "Detect a running Home Assistant instance"
+          if [ "$?" != "0" ]; then
+            echo "Home Assistant Core did not start within 10 minutes"
+            exit 1
+          fi
+
       - name: Create full backup
         id: backup
         run: |

supervisor/homeassistant/module.py

@@ -371,6 +371,12 @@ class HomeAssistant(FileConfiguration, CoreSysAttributes):
                 _LOGGER.error,
             ) from err
 
+        if not resp:
+            raise HomeAssistantBackupError(
+                "Preparing backup of Home Assistant Core failed. No response from HA Core.",
+                _LOGGER.error,
+            )
+
         if resp and not resp.get(ATTR_SUCCESS):
             raise HomeAssistantBackupError(
                 f"Preparing backup of Home Assistant Core failed due to: {resp.get(ATTR_ERROR, {}).get(ATTR_MESSAGE, '')}. Check HA Core logs.",

supervisor/homeassistant/websocket.py

@@ -225,6 +225,10 @@ class HomeAssistantWebSocket(CoreSysAttributes):
         # since it makes a new socket connection and we already have one.
         if not connected and not await self.sys_homeassistant.api.check_api_state():
             # No core access, don't try.
+            _LOGGER.debug(
+                "Home Assistant API is not accessible. Not sending WS message: %s",
+                message,
+            )
             return False
 
         if not self._client: