add some error handling to mqtt relay

frigate/http.py

@@ -39,25 +39,39 @@ class MqttBackend():
         self.clients.append(client)
 
     def publish(self, message):
-        json_message = json.loads(message)
-        self.mqtt_client.publish(f"{self.topic_prefix}/{json_message['topic']}", json_message['payload'], retain=json_message['retain'])
+        try:
+            json_message = json.loads(message)
+            json_message = {
+                'topic': f"{self.topic_prefix}/{json_message['topic']}",
+                'payload': json_message.get['payload'],
+                'retain': json_message.get('retain', False)
+            }
+        except:
+            logger.warning("Unable to parse websocket message as valid json.")
+            return
+
+        logger.debug(f"Publishing mqtt message from websockets at {json_message['topic']}.")
+        self.mqtt_client.publish(json_message['topic'], json_message['payload'], retain=json_message['retain'])
 
     def run(self):
         def send(client, userdata, message):
             """Sends mqtt messages to clients."""
             try:
+                logger.debug(f"Received mqtt message on {message.topic}.")
                 ws_message = json.dumps({
                     'topic': message.topic.replace(f"{self.topic_prefix}/",""),
                     'payload': message.payload.decode()
                 })
             except:
                 # if the payload can't be decoded don't relay to clients
+                logger.debug(f"MQTT payload for {message.topic} wasn't text. Skipping...")
                 return
 
             for client in self.clients:
                 try:
                     client.send(ws_message)
                 except:
+                    logger.debug("Removing websocket client due to a closed connection.")
                     self.clients.remove(client)
         
         self.mqtt_client.message_callback_add(f"{self.topic_prefix}/#", send)