rename

src/util/mqtt.py

@@ -0,0 +1,73 @@
+import queue
+from dataclasses import dataclass
+
+from fastapi_mqtt import FastMQTT, MQTTConfig
+
+
+@dataclass
+class MQTTSubscription:
+    topic: str
+    callback: callable
+    subscribed: bool
+
+
+@dataclass
+class MQTTPendingMessage:
+    topic: str
+    payload: dict
+    retain: bool
+
+
+class MQTT:
+    _instance = None
+
+    def __new__(cls, *args, **kwargs):  # noqa: ANN002, ANN003, ANN204
+        if not cls._instance:
+            cls._instance = super().__new__(cls, *args, **kwargs)
+        return cls._instance
+
+    def __init__(self) -> None:
+        self._mqtt_config = MQTTConfig(username="mqtt", password="mqtt", reconnect_retries=-1)  # noqa: S106
+        self._mqtt = FastMQTT(config=self._mqtt_config, client_id="home_automation_backend")
+        self._mqtt.mqtt_handlers.user_connect_handler = self.on_connect
+        self._mqtt.mqtt_handlers.user_message_handler = self.on_message
+        self._connected = False
+        self._subscribed_topic: dict[str, MQTTSubscription] = {}
+        self._queued_message: queue.Queue[MQTTPendingMessage] = queue.Queue()
+
+    async def start(self) -> None:
+        print("MQTT Starting...")
+        await self._mqtt.mqtt_startup()
+
+    async def stop(self) -> None:
+        print("MQTT Stopping...")
+        await self._mqtt.mqtt_shutdown()
+
+    def on_connect(self, client, flags, rc, properties) -> None:  # noqa: ANN001, ARG002
+        print("Connected")
+        self._connected = True
+        while not self._queued_message.empty():
+            msg = self._queued_message.get(block=False)
+            self.publish(msg.topic, msg.payload, retain=msg.retain)
+        for topic, subscription in self._subscribed_topic.items():
+            if subscription.subscribed is False:
+                self.subscribe(topic, subscription.callback)
+
+    async def on_message(self, client, topic: str, payload: bytes, qos: int, properties: any) -> any:  # noqa: ANN001, ARG002
+        print("On message")
+        if topic in self._subscribed_topic and self._subscribed_topic[topic].callback is not None:
+            await self._subscribed_topic[topic].callback(payload)
+
+    def subscribe(self, topic: str, callback: callable) -> None:
+        if self._connected:
+            print("Subscribe to topic: ", topic)
+            self._mqtt.client.subscribe(topic)
+            self._subscribed_topic[topic] = MQTTSubscription(topic, callback, subscribed=True)
+        else:
+            self._subscribed_topic[topic] = MQTTSubscription(topic, callback, subscribed=False)
+
+    def publish(self, topic: str, payload: dict, *, retain: bool) -> None:
+        if self._connected:
+            self._mqtt.publish(topic, payload=payload, retain=retain)
+        else:
+            self._queued_message.put(MQTTPendingMessage(topic, payload, retain=retain))