fix: actor waits for beamline state to become available

Author: d-perl

bec_lib/bec_lib/bl_state_manager.py

@@ -114,11 +114,18 @@ def __init__(self, client: BECClient) -> None:
         self._connector.register(
             MessageEndpoints.available_beamline_states(), cb=self._on_state_update, from_start=True
         )
+        self._ready = False
+
+    @property
+    def ready(self) -> bool:
+        """Returns true after beamline states have been loaded from Redis."""
+        return self._ready
 
     def _on_state_update(self, msg_dict: dict, **_kwargs) -> None:
         # type: ignore ; we know it's an AvailableBeamlineStatesMessage
         msg: messages.AvailableBeamlineStatesMessage = msg_dict["data"]
         self._update_states(msg.states)  # pylint: disable=protected-access
+        self._ready = True
 
     def _update_state(self, state: BeamlineStateConfig) -> None:
         if state.name in self._states:

bec_server/bec_server/actors/actor.py

@@ -128,8 +128,6 @@ def __init__(self, client: BECClient, name: str, exec_id: str):
         }
         super().__init__(client, name, exec_id)
         self.state_cache: dict[str, BlStateStatus] = {}
-        self._update_cache()
-        self.evaluate()
 
     def _update_cache(self):
         with self.state_table_lock:
@@ -164,6 +162,14 @@ def all_match_action(self, client: BECClient):
     def some_mismatch_action(self, client: BECClient):
         pass
 
+    def run(self):
+        while not self.client.beamline_states.ready:
+            logger.warning(f"{self.__class__.__name__} waiting for beamline states to become ready")
+            time.sleep(0.1)
+        self._update_cache()
+        self.evaluate()
+        return super().run()
+
     def default_monitor_endpoints(self) -> set[EndpointInfo]:
         return {MessageEndpoints.beamline_state(state) for state in self.state_table}