Added option to provide an existing mqtt client.

README.md

@@ -36,6 +36,7 @@ Using MQTT discoverable devices lets us add new sensors and devices to HA withou
   - [Text](#text)
     - [Usage](#usage-8)
 - [FAQ](#faq)
+  - [Using an existing MQTT client](#using-an-existing-mqtt-client)
   - [I'm having problems on 32 bit ARM](#im-having-problems-on-32-bit-arm)
 - [Contributing](#contributing)
 - [Users of ha-mqtt-discoverable](#users-of-ha-mqtt-discoverable)
@@ -491,6 +492,26 @@ my_text.set_text("Some awesome text")
 
 ## FAQ
 
+### Using an existing MQTT client
+
+If you want to use an existing MQTT client for the connection, you can pass it to the `Settings` object:
+
+```py
+from ha_mqtt_discoverable import Settings
+from paho.mqtt.client import Client
+
+# Creating the MQTT client
+client = Client()
+# Doing other stuff with the client, like connecting to the broker
+# ...
+
+# Providing the client to the Settings object
+# In this case, no other MQTT settings are needed
+mqtt_settings = Settings.MQTT(client=client)
+
+# Continue with the rest of the code as usual
+```
+
 ### I'm having problems on 32 bit ARM
 
 Pydantic 2 has issues on 32 bit ARM. More details are on [ha-mqtt-discoverable/pull/191](https://github.com/unixorn/ha-mqtt-discoverable/pull/191). TL;DR: If you're on an ARM32 machine you're going to have to pin to the 0.13.1 version.

ha_mqtt_discoverable/__init__.py

@@ -16,7 +16,7 @@
 import logging
 import ssl
 from importlib import metadata
-from typing import Any, Callable, Generic, Optional, TypeVar
+from typing import Any, Callable, Generic, Optional, TypeVar, Union
 
 import paho.mqtt.client as mqtt
 from paho.mqtt.client import MQTTMessageInfo
@@ -546,7 +546,11 @@ class Settings(BaseModel, Generic[EntityType]):
     class MQTT(BaseModel):
         """Connection settings for the MQTT broker"""
 
-        host: str
+        class Config:
+            # To use mqtt.Client
+            arbitrary_types_allowed = True
+
+        host: Optional[str] = "homeassistant"
         port: Optional[int] = 1883
         username: Optional[str] = None
         password: Optional[str] = None
@@ -561,6 +565,9 @@ class MQTT(BaseModel):
         state_prefix: str = "hmd"
         """The root of the topic tree ha-mqtt-discovery publishes its state messages"""
 
+        client: Optional[mqtt.Client] = None
+        """Optional MQTT client to use for the connection. If provided, most other settings are ignored."""
+
     mqtt: MQTT
     """Connection to MQTT broker"""
     entity: EntityType
@@ -640,7 +647,7 @@ def __init__(self, settings: Settings[EntityType], on_connect: Optional[Callable
         self._setup_client(on_connect)
         # If there is a callback function defined, the user must manually connect
         # to the MQTT client
-        if not on_connect:
+        if not (on_connect or self._settings.mqtt.client is not None):
             self._connect_client()
 
     def __str__(self) -> str:
@@ -658,9 +665,16 @@ def __str__(self) -> str:
 
     def _setup_client(self, on_connect: Optional[Callable] = None) -> None:
         """Create an MQTT client and setup some basic properties on it"""
+
+        # If the user has passed in an MQTT client, use it
+        if self._settings.mqtt.client:
+            self.mqtt_client = self._settings.mqtt.client
+            return
+
         mqtt_settings = self._settings.mqtt
         logger.debug(f"Creating mqtt client ({mqtt_settings.client_name}) for " f"{mqtt_settings.host}:{mqtt_settings.port}")
-        self.mqtt_client = mqtt.Client(mqtt_settings.client_name)
+        # Use named parameter to add compatibility with paho-mqtt >2.0.0
+        self.mqtt_client = mqtt.Client(client_id=mqtt_settings.client_name)
         if mqtt_settings.tls_key:
             logger.info(f"Connecting to {mqtt_settings.host}:{mqtt_settings.port} with SSL and client certificate authentication")
             logger.debug(f"ca_certs={mqtt_settings.tls_ca_cert}")
@@ -703,7 +717,7 @@ def _setup_client(self, on_connect: Optional[Callable] = None) -> None:
     def _connect_client(self) -> None:
         """Connect the client to the MQTT broker, start its onw internal loop in
         a separate thread"""
-        result = self.mqtt_client.connect(self._settings.mqtt.host, self._settings.mqtt.port)
+        result = self.mqtt_client.connect(self._settings.mqtt.host, self._settings.mqtt.port or 1883)
         # Check if we have established a connection
         if result != mqtt.MQTT_ERR_SUCCESS:
             raise RuntimeError("Error while connecting to MQTT broker")
@@ -712,7 +726,9 @@ def _connect_client(self) -> None:
         # messages in a separate thread
         self.mqtt_client.loop_start()
 
-    def _state_helper(self, state: Optional[str], topic: Optional[str] = None, retain=True) -> MQTTMessageInfo:
+    def _state_helper(
+        self, state: Optional[Union[str, float, int]], topic: Optional[str] = None, retain=True
+    ) -> Optional[MQTTMessageInfo]:
         """
         Write a state to the given MQTT topic, returning the result of client.publish()
         """