Use hbmqtt with prompt_toolkit

mqtt_monitor.py

import asyncio
import logging

from hbmqtt.client import MQTTClient, ClientException
from hbmqtt.mqtt.constants import QOS_0
from prompt_toolkit.application import Application
from prompt_toolkit.key_binding import KeyBindings
from prompt_toolkit.layout import Layout
from prompt_toolkit.widgets import Frame, TextArea
from natsort import natsorted


class Monitor:
    def __init__(self):
        self.data = {}
        self.client = MQTTClient()
        self.text_area = TextArea(multiline=True, read_only=True)
        layout = Layout(
            Frame(self.text_area)
        )

        kb = KeyBindings()

        @kb.add('c-c')
        def exit_(event):
            self.application.exit()

        self.application = Application(layout=layout, key_bindings=kb)

    async def run(self):
        await self.connect()
        loop_future = asyncio.ensure_future(self.message_loop())
        await self.application.run_async()
        loop_future.cancel()

    async def connect(self):
        await self.client.connect('mqtt://localhost/')
        await self.client.subscribe([
            ('$SYS/broker/load/#', QOS_0),
        ])

    async def disconnect(self):
        await self.client.unsubscribe(['$SYS/broker/load/#'])
        await self.client.disconnect()

    async def message_loop(self):
        while True:
            try:
                message = await self.client.deliver_message()
                self.data[message.topic] = message.data.decode()
                self.update_text()
            except ClientException as ce:
                logging.error('Client exception: %s' % ce)
            except asyncio.CancelledError:
                logging.debug('Loop exited')
                await self.disconnect()

    def update_text(self):
        self.text_area.text = '\n'.join([
            f'{topic} => {data}'
            for topic, data
            in natsorted(self.data.items())
        ])


if __name__ == '__main__':
    logging.basicConfig()
    monitor = Monitor()
    asyncio.get_event_loop().run_until_complete(monitor.run())

requirements.txt

prompt-toolkit~=3.0.2
hbmqtt~=0.9.5
natsort~=7.0.0