[EXAMPLE] Using signals instead of callbacks

radio/app/controllers/armController.py

@@ -4,6 +4,7 @@
 from threading import current_thread
 from typing import TYPE_CHECKING
 
+from app.signals import DroneError
 from app.customTypes import Response
 from app.utils import commandAccepted, sendingCommandLock
 from pymavlink import mavutil
@@ -87,8 +88,11 @@ def arm(self, force: bool = False) -> Response:
 
         except Exception as e:
             self.drone.logger.error(e, exc_info=True)
-            if self.drone.droneErrorCb:
-                self.drone.droneErrorCb(str(e))
+            self.drone.error(str(e))
+
+            ## Or you can have just have:                 (TODO: remove)
+            DroneError.send(self, msg=str(e))
+
             return {
                 "success": False,
                 "message": "Could not arm, serial exception",

radio/app/drone.py

@@ -27,6 +27,7 @@
 from app.controllers.serialPortsController import SerialPortsController
 from app.controllers.servoController import ServoController
 from app.customTypes import Number, Response, VehicleType
+from app.signals import DroneError, DroneConnectStatus
 from app.utils import (
     commandAccepted,
     decodeFlightSwVersion,
@@ -82,7 +83,6 @@ def __init__(
         forwarding_address: Optional[str] = None,
         droneErrorCb: Optional[Callable] = None,
         droneDisconnectCb: Optional[Callable] = None,
-        droneConnectStatusCb: Optional[Callable] = None,
         linkDebugStatsCb: Optional[Callable] = None,
         fetchingParameterCb: Optional[Callable] = None,
         connectionCancelEvent: Optional[Event] = None,
@@ -95,7 +95,6 @@ def __init__(
             baud (int, optional): The baud rate for the connection. Defaults to 57600.
             droneErrorCb (Optional[Callable], optional): Callback function for drone errors. Defaults to None.
             droneDisconnectCb (Optional[Callable], optional): Callback function for drone disconnection. Defaults to None.
-            droneConnectStatusCb (Optional[Callable], optional): Callback function for drone connection providing an update as the drone connects. Defaults to None.
             linkDebugStatsCb (Optional[Callable], optional): Callback function for link debug stats. Defaults to None.
             fetchingParameterCb (Optional[Callable], optional): Callback function for when parameters are being fetched. Defaults to None.
             connectionCancelEvent (Optional[Event], optional): Event to signal if the connection process should be cancelled. Defaults to None.
@@ -105,7 +104,6 @@ def __init__(
         self.logger = logger
         self.droneErrorCb = droneErrorCb
         self.droneDisconnectCb = droneDisconnectCb
-        self.droneConnectStatusCb = droneConnectStatusCb
         self.linkDebugStatsCb = linkDebugStatsCb
         self.fetchingParameterCb = fetchingParameterCb
         self.connection_cancel_event: Event = connectionCancelEvent or Event()
@@ -371,9 +369,6 @@ def setupControllers(self) -> None:
     def _emitConnectionStatus(
         self, message: str, progress: float, sub_message: str = ""
     ) -> None:
-        if not self.droneConnectStatusCb:
-            return
-
         progress = round(min(max(float(progress), 0.0), 100.0), 2)
         progress = max(progress, self._last_connect_progress)
         payload = {
@@ -386,7 +381,7 @@ def _emitConnectionStatus(
             return
 
         try:
-            self.droneConnectStatusCb(payload)
+            DroneConnectStatus.send(self, msg=payload)
         except Exception:
             self.logger.exception("Connection status callback failed")
             return
@@ -739,8 +734,7 @@ def checkForMessages(self) -> None:
                 msg = self.master.recv_msg()
             except mavutil.mavlink.MAVError as e:
                 self.logger.error(e, exc_info=True)
-                if self.droneErrorCb:
-                    self.droneErrorCb(str(e))
+                self.error(str(e))
                 continue
             except AttributeError as e:
                 self.logger.error(e, exc_info=True)
@@ -755,8 +749,7 @@ def checkForMessages(self) -> None:
             except Exception as e:
                 # Log any other unexpected exception
                 self.logger.error(e, exc_info=True)
-                if self.droneErrorCb:
-                    self.droneErrorCb(str(e))
+                self.error(str(e))
                 continue
 
             if msg is None:
@@ -1264,6 +1257,9 @@ def stopForwarding(self) -> Response:
         else:
             return {"success": False, "message": "Not currently forwarding"}
 
+    def error(self, msg: str) -> None:
+        DroneError.send(self, msg=msg)
+
     def close(self) -> None:
         """Close the connection to the drone."""
         self.logger.info(f"Cleaning up resources for drone at {self}")

radio/app/endpoints/autopilot.py

@@ -20,7 +20,6 @@ def rebootAutopilot() -> None:
     baud = droneStatus.drone.baud
     droneErrorCb = droneStatus.drone.droneErrorCb
     droneDisconnectCb = droneStatus.drone.droneDisconnectCb
-    droneConnectStatusCb = droneStatus.drone.droneConnectStatusCb
     linkDebugStatsCb = droneStatus.drone.linkDebugStatsCb
     fetchingParameterCb = droneStatus.drone.fetchingParameterCb
     forwarding_address = droneStatus.drone.forwarding_address
@@ -54,7 +53,6 @@ def rebootAutopilot() -> None:
             forwarding_address=forwarding_address,
             droneErrorCb=droneErrorCb,
             droneDisconnectCb=droneDisconnectCb,
-            droneConnectStatusCb=droneConnectStatusCb,
             linkDebugStatsCb=linkDebugStatsCb,
             fetchingParameterCb=fetchingParameterCb,
         )

radio/app/endpoints/comPorts.py

@@ -10,7 +10,6 @@
 from app import logger, socketio
 from app.drone import Drone
 from app.utils import (
-    droneConnectStatusCb,
     droneErrorCb,
     fetchingParameterCb,
     getComPortNames,
@@ -157,7 +156,6 @@ def connectToDrone(data: ConnectionDataType) -> None:
             forwarding_address=forwarding_address,
             droneErrorCb=droneErrorCb,
             droneDisconnectCb=disconnectFromDrone,
-            droneConnectStatusCb=droneConnectStatusCb,
             linkDebugStatsCb=sendLinkDebugStats,
             fetchingParameterCb=fetchingParameterCb,
             connectionCancelEvent=cancel_event,

radio/app/signals.py

@@ -0,0 +1,47 @@
+from blinker import Signal
+from . import socketio
+
+from typing import TypedDict, NotRequired
+from app.customTypes import Number
+
+import logging
+
+logger = logging.getLogger("fgcs")
+
+# Define signals
+DroneError = Signal()
+DroneConnectStatus = Signal()
+
+
+@DroneError.connect
+def droneErrorHandler(sender, msg: str) -> None:
+    """
+    Send drone error to the socket
+
+    Args:
+        msg: The error message to send to the client
+    """
+    logger.debug(f"dronErrorHandler called by: {sender} with msg: {msg}")
+    socketio.emit("drone_error", {"message": msg})
+
+    ## Optionally you can add return values
+    ## That would be what the function would return to the caller
+    # return {success: true}
+
+
+class DroneConnectionStatusDataType(TypedDict):
+    message: str
+    progress: Number
+    sub_message: NotRequired[str]
+
+
+@DroneConnectStatus.connect
+def droneConnectStatusHandler(sender, msg: DroneConnectionStatusDataType) -> None:
+    """
+    Send drone connect status updates to the socket
+
+    Args:
+        msg: The connect message to send to the client
+    """
+    logger.debug(f"droneConnectStatusHandler called by: {sender} with msg: {msg}")
+    socketio.emit("drone_connect_status", msg)

radio/app/utils.py

@@ -4,9 +4,8 @@
 
 from pymavlink import mavutil
 from serial.tools import list_ports
-from typing_extensions import NotRequired, TypedDict
 
-from app.customTypes import Number, VehicleType
+from app.customTypes import VehicleType
 
 from . import socketio
 
@@ -148,22 +147,6 @@ def droneErrorCb(msg: Any) -> None:
     socketio.emit("drone_error", {"message": msg})
 
 
-class ConnectionDataType(TypedDict):
-    message: str
-    progress: Number
-    sub_message: NotRequired[str]
-
-
-def droneConnectStatusCb(msg: ConnectionDataType) -> None:
-    """
-    Send drone connect status updates to the socket
-
-    Args:
-        msg: The connect message to send to the client
-    """
-    socketio.emit("drone_connect_status", msg)
-
-
 def notConnectedError(action: Optional[str] = None) -> None:
     """
     Send error to the socket indicating that drone connection must be established to complete this action

radio/mypy.ini

@@ -13,3 +13,5 @@ ignore_missing_imports = True
 ignore_missing_imports = True
 [mypy-docker.*]
 ignore_missing_imports = True
+[mypy-blinker.*]
+ignore_missing_imports = True