rename main to node_main for IDE clarity

Dockerfile

@@ -49,4 +49,4 @@ RUN sed -i 's/\r$//' /usr/local/bin/docker-entrypoint.sh && \
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
 
 # 3. Use CMD to pass the uvicorn command as arguments to the ENTRYPOINT script
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8001", "--reload"]
+CMD ["uvicorn", "node_main:app", "--host", "0.0.0.0", "--port", "8001", "--reload"]

app/node_main.py

@@ -1,6 +1,7 @@
 import asyncio
 import json
 import os
+import signal
 from datetime import datetime
 from fastapi import FastAPI
 from routers.op25_controller import create_op25_router
@@ -12,14 +13,17 @@ import requests
 # Initialize logging
 LOGGER = create_logger(__name__)
 
+# FastAPI App
 app = FastAPI(title="Radio Edge Supervisor")
-
-# Add the router
 app.include_router(create_op25_router(), prefix="/op25")
 
+# Configuration
 NODE_ID = os.getenv("NODE_ID", "standalone-node")
 MQTT_BROKER = os.getenv("MQTT_BROKER", None)
 
+# Global flag to track MQTT connection state
+MQTT_CONNECTED = False
+
 def handle_c2_command(topic, payload):
     """
     Parses and routes commands received from the C2 server by calling the
@@ -106,79 +110,100 @@ def handle_c2_command(topic, payload):
     except Exception as e:
         LOGGER.error(f"Error processing C2 command: {e}")
 
-async def mqtt_phone_home():
+async def mqtt_lifecycle_manager():
     """
-    Maintains a persistent C2 connection using a single MQTT client.
-    Handles check-ins and command subscriptions via callbacks.
+    Manages the application-level logic: Check-in, Heartbeats, and Shutdown.
+    Decoupled from the Paho MQTT network loop.
     """
+    global MQTT_CONNECTED
+    
     if not MQTT_BROKER:
         LOGGER.info("No MQTT_BROKER defined. Running in standalone mode.")
         return
 
-    # Create a single client instance
     client = mqtt.Client(client_id=NODE_ID)
 
+    # --- Callbacks ---
     def on_connect(client, userdata, flags, rc):
+        global MQTT_CONNECTED
         if rc == 0:
-            LOGGER.info(f"Successfully connected to MQTT Broker: {MQTT_BROKER}")
-            
-            # 1. Subscribe to command topics for this specific node
-            command_topic = f"nodes/{NODE_ID}/commands"
-            client.subscribe(command_topic)
-            LOGGER.info(f"Subscribed to {command_topic}")
-
-            # 2. Perform Initial Check-In with OP25 status
-            try:
-                status_response = requests.get("http://localhost:8001/op25/status")
-                op25_status = status_response.json() if status_response.ok else {}
-            except requests.RequestException:
-                op25_status = {"is_running": False, "active_system": None}
-
-            checkin_data = {
-                "node_id": NODE_ID,
-                "status": "online",
-                "timestamp": datetime.now().isoformat(),
-                "version": "1.0.0",
-                "is_listening": op25_status.get("is_running", False),
-                "active_system": op25_status.get("active_system"),
-                "available_systems": scan_local_library()
-            }
-            client.publish(f"nodes/{NODE_ID}/checkin", json.dumps(checkin_data), retain=True)
+            LOGGER.info(f"Connected to MQTT Broker: {MQTT_BROKER}")
+            client.subscribe(f"nodes/{NODE_ID}/commands")
+            MQTT_CONNECTED = True
         else:
-            LOGGER.error(f"MQTT Connection failed with return code {rc}")
-
-    def on_message(client, userdata, msg):
-        # Handle messages arriving on subscribed topics
-        handle_c2_command(msg.topic, msg.payload.decode())
+            LOGGER.error(f"MQTT Connection failed: {rc}")
 
     def on_disconnect(client, userdata, rc):
+        global MQTT_CONNECTED
+        MQTT_CONNECTED = False
         if rc != 0:
-            LOGGER.warning("Unexpected MQTT disconnection. Paho will attempt to reconnect...")
+            LOGGER.warning("Unexpected MQTT disconnection.")
 
-    # Set up callbacks and LWT
+    def on_message(client, userdata, msg):
+        handle_c2_command(msg.topic, msg.payload.decode())
+
+    # --- Setup ---
     client.on_connect = on_connect
     client.on_message = on_message
     client.on_disconnect = on_disconnect
-    
-    lwt_payload = json.dumps({"node_id": NODE_ID, "status": "offline"})
+
+    # LWT: Fires ONLY on ungraceful crash/timeout
+    lwt_payload = json.dumps({"status": "offline", "reason": "unexpected_disconnect"})
     client.will_set(f"nodes/{NODE_ID}/status", lwt_payload, qos=1, retain=True)
 
     try:
-        # Connect and start the background loop thread
-        # loop_start() handles reconnections automatically without spaming new clients
         client.connect(MQTT_BROKER, 1883, 60)
-        client.loop_start()
+        client.loop_start() # Run network loop in background thread
         
-        # Keep the async task alive indefinitely
+        # --- Main Heartbeat Loop ---
         while True:
-            await asyncio.sleep(3600)
+            if MQTT_CONNECTED:
+                # 1. Gather Data (This was previously in on_connect)
+                try:
+                    status_response = requests.get("http://localhost:8001/op25/status", timeout=2)
+                    op25_status = status_response.json() if status_response.ok else {}
+                except Exception:
+                    op25_status = {"is_running": False}
+
+                payload = {
+                    "node_id": NODE_ID,
+                    "status": "online",
+                    "timestamp": datetime.now().isoformat(),
+                    "is_listening": op25_status.get("is_running", False),
+                    "active_system": op25_status.get("active_system"),
+                    # Only scan library if needed, otherwise it's heavy I/O
+                    "available_systems": scan_local_library() 
+                }
+
+                # 2. Publish Heartbeat (Acts as both check-in and keep-alive)
+                client.publish(f"nodes/{NODE_ID}/checkin", json.dumps(payload), retain=True)
+                LOGGER.debug("Sent Heartbeat/Check-in")
             
-    except Exception as e:
-        LOGGER.error(f"Fatal error in MQTT supervisor: {e}")
+            # Pulse every 30 seconds
+            await asyncio.sleep(30)
+
+    except asyncio.CancelledError:
+        LOGGER.info("Stopping MQTT Loop...")
     finally:
+        # Graceful Shutdown: Explicitly tell C2 we are leaving
+        if MQTT_CONNECTED:
+            shutdown_payload = json.dumps({"status": "offline", "reason": "clean_shutdown"})
+            client.publish(f"nodes/{NODE_ID}/status", shutdown_payload, qos=1, retain=True)
+        
         client.loop_stop()
+        client.disconnect()
 
 @app.on_event("startup")
 async def startup_event():
-    # Start the C2 connection in the background. 
-    asyncio.create_task(mqtt_phone_home())
+    # Store the task so we can cancel it if needed (optional)
+    app.state.mqtt_task = asyncio.create_task(mqtt_lifecycle_manager())
+
+@app.on_event("shutdown")
+async def shutdown_event():
+    # Cancel the loop to trigger the finally block
+    if hasattr(app.state, "mqtt_task"):
+        app.state.mqtt_task.cancel()
+        try:
+            await app.state.mqtt_task
+        except asyncio.CancelledError:
+            pass