mqtt_client.py: connect to mixer on demand

mixer.py

@@ -46,6 +46,12 @@ class Mixer:
         self.qu_midi_channel = self.get_system_state().midi_channel
         self.daw_midi_channel = self.qu_midi_channel + 1
 
+    def __del__(self):
+        # This final recv is used to keep the connection open a bit.
+        # If socket connection is closed to early, previous command may not be executed:
+        self.recv_sys_ex()
+
+
     ALLEN_HEATH_ID = [0x00, 0x00, 0x1A]
     QU_MIXER = [0x50, 0x11]
     MAJOR_MINOR = [0x01, 0x00]

mqtt_client.py

@@ -13,7 +13,7 @@ class MqttClient:
     MQTT_COMMAND_TOPIC = "livingroom/voc/allen_heath_qu16_mixer"
 
     def __init__(self, mixer_ip):
-        self.mixer = Mixer(mixer_ip)
+        self.mixer_ip = mixer_ip
         self.client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2)
 
     def mqtt_autodiscovery(self):
@@ -48,11 +48,13 @@ class MqttClient:
 
         j = json.loads(payload)
 
+        mixer = Mixer(self.mixer_ip)
+
         match j["command"]:
             case "scene_recall":
-                self.mixer.scene_recall(j["args"]["scene_id"])
+                mixer.scene_recall(j["args"]["scene_id"])
             case "shutdown":
-                self.mixer.shutdown()
+                mixer.shutdown()
 
     def run(self, hostname):
         self.client.on_connect = self.on_connect