allow to set user data in the init method

[vladak]

This change allows to set the opaque user data in the init method. Works like this:

"""
MQTT utility functions
"""
import ssl

import adafruit_logging as logging
import adafruit_minimqtt.adafruit_minimqtt as MQTT

# pylint: disable=unused-argument, redefined-outer-name, invalid-name
def connect(mqtt_client, userdata, flags, rc):
    """
    This function will be called when the mqtt_client is connected
    successfully to the broker.
    """
    logger = userdata

    logger.info("Connected to MQTT Broker!")
    logger.debug(f"Flags: {flags}\n RC: {rc}")


# pylint: disable=unused-argument, invalid-name
def disconnect(mqtt_client, userdata, rc):
    """
    This method is called when the mqtt_client disconnects from the broker.
    """
    logger = userdata

    logger.info("Disconnected from MQTT Broker!")


def publish(mqtt_client, userdata, topic, pid):
    """
    This method is called when the mqtt_client publishes data to a feed.
    """
    logger = userdata

    logger.info(f"Published to {topic} with PID {pid}")


def mqtt_client_setup(pool, broker, port):
    """
    Set up a MiniMQTT Client
    """

    logger = logging.getLogger("mqtt")
    logger.setLevel(logging.DEBUG)

    mqtt_client = MQTT.MQTT(
        broker=broker,
        port=port,
        socket_pool=pool,
        ssl_context=ssl.create_default_context(),
        user_data=logger,
    )

    mqtt_client.on_connect = connect
    mqtt_client.on_disconnect = disconnect
    mqtt_client.on_publish = publish

    return mqtt_client


def main():
    import socket
    mqtt_client = mqtt_client_setup(broker="localhost", port=1883, pool=socket)
    mqtt_client.connect()
    mqtt_client.publish("foo/bar", "msg")


if __name__ == "__main__":
    main()

Tested with CPython against custom MQTT broker implementation, produces the following output:

601394.401: INFO - Connected to MQTT Broker!
601394.401: DEBUG - Flags: 0
 RC: 0
601394.401: INFO - Published to foo/bar with PID 0

[FoamyGuy]

Makes sense, and looks good to me.

It's interesting this was partially implemented already, but seemingly no way to actually set the data, and none of the examples made use of it.

I tested it successfully on a Feather ESP32-S2 TFT with a modified simpletest that sets an object as userdata and accesses it from each of the callback functions.