Create FileWatcher when ConfigManagingActor runs

The ConfigManagingActor was unable to process events
after being restarted because the FileWatcher cannot
be reused when the ConfigManagingActor is restarted,
so we need to create a new instance every time the
actor starts running.

Signed-off-by: Daniel Zullo <[email protected]>

Author: daniel-zullo-frequenz

RELEASE_NOTES.md

@@ -14,4 +14,4 @@
 
 ## Bug Fixes
 
-<!-- Here goes notable bug fixes that are worth a special mention or explanation -->
+- `ConfigManagingActor`: Fixed an issue where the actor was unable to process events after being restarted.

src/frequenz/sdk/config/_config_managing.py

@@ -52,13 +52,8 @@ def __init__(
             if isinstance(config_path, pathlib.Path)
             else pathlib.Path(config_path)
         )
-        # FileWatcher can't watch for non-existing files, so we need to watch for the
-        # parent directory instead just in case a configuration file doesn't exist yet
-        # or it is deleted and recreated again.
-        self._file_watcher: FileWatcher = FileWatcher(
-            paths=[self._config_path.parent], event_types=event_types
-        )
         self._output: Sender[abc.Mapping[str, Any]] = output
+        self._event_types: abc.Set[EventType] = event_types
 
     def _read_config(self) -> abc.Mapping[str, Any]:
         """Read the contents of the configuration file.
@@ -90,32 +85,42 @@ async def _run(self) -> None:
         """
         await self.send_config()
 
-        async for event in self._file_watcher:
-            # Since we are watching the whole parent directory, we need to make sure
-            # we only react to events related to the configuration file.
-            if not event.path.samefile(self._config_path):
-                continue
-
-            match event.type:
-                case EventType.CREATE:
-                    _logger.info(
-                        "%s: The configuration file %s was created, sending new config...",
-                        self,
-                        self._config_path,
-                    )
-                    await self.send_config()
-                case EventType.MODIFY:
-                    _logger.info(
-                        "%s: The configuration file %s was modified, sending update...",
-                        self,
-                        self._config_path,
-                    )
-                    await self.send_config()
-                case EventType.DELETE:
-                    _logger.info(
-                        "%s: The configuration file %s was deleted, ignoring...",
-                        self,
-                        self._config_path,
-                    )
-                case _:
-                    assert_never(event.type)
+        # FileWatcher can't watch for non-existing files, so we need to watch for the
+        # parent directory instead just in case a configuration file doesn't exist yet
+        # or it is deleted and recreated again.
+        file_watcher = FileWatcher(
+            paths=[self._config_path.parent], event_types=self._event_types
+        )
+
+        try:
+            async for event in file_watcher:
+                # Since we are watching the whole parent directory, we need to make sure
+                # we only react to events related to the configuration file.
+                if not event.path.samefile(self._config_path):
+                    continue
+
+                match event.type:
+                    case EventType.CREATE:
+                        _logger.info(
+                            "%s: The configuration file %s was created, sending new config...",
+                            self,
+                            self._config_path,
+                        )
+                        await self.send_config()
+                    case EventType.MODIFY:
+                        _logger.info(
+                            "%s: The configuration file %s was modified, sending update...",
+                            self,
+                            self._config_path,
+                        )
+                        await self.send_config()
+                    case EventType.DELETE:
+                        _logger.info(
+                            "%s: The configuration file %s was deleted, ignoring...",
+                            self,
+                            self._config_path,
+                        )
+                    case _:
+                        assert_never(event.type)
+        finally:
+            del file_watcher