trio_paho_mqtt

trio specific async MQTT client. The goal of this project is to have all the MQTT protocol stuff handled by paho-mqtt, while the async loopy stuff is handled by trio. This keeps our MQTT communication async, without having to shove paho-mqtt into a thread, and without having to reimplement the MQTT protocol.

All callbacks are also removed to be more trio-like. Messages are accessed through an async for loop.

This is meant to be a light-as-possible wrapper around paho-mqtt. That way if something goes wrong with MQTT message parsing, it's not my fault ;-)

Usage

First, see the example.py and paho-mqtt documentation. The goal is to expose all the same methods as the paho-mqtt Client. If any methods (besides callbacks) are missing or do something unexpected, this is a bug. Please open an issue.

AsyncClient is initialized with a sync mqtt.Client and a trio.Nursery but then otherwise should operate much like the sync Client. Methods are not coroutines, they are non-blocking functions, so you do not need to call await. The only exception is accessing messages through async for.

Example

import paho.mqtt.client as mqtt
import trio
from trio_paho_mqtt import AsyncClient


async def handle_messages(client):
    async for msg in client.messages():
        print(f"Received msg: {msg}")

async with trio.open_nursery() as nursery:
    sync_client = mqtt.Client()
    client = AsyncClient(sync_client, nursery)
    client.connect('mqtt.eclipse.org', 1883, 60)
    client.subscribe(topic)
    client.publish(topic, msg)

    nursery.start_soon(handle_messages, client)

Related projects

• gmqtt - Uses asyncio and callbacks. Isn't compatible with trio.
• hbmqtt - Uses asyncio. Reimplements the MQTT protocol.
• aiomqtt - Uses asyncio and wraps paho, but still uses the loop from paho-mqtt. I believe all operations are put into a worker thread.
• distmqtt - anyio-ified hbmqtt fork. Works with trio.