mqtt_client.py

'''
IoT: Internet of Things
server : iot.codelab.club

# tool:
    pip3 install hbmqtt # 0.9.5
    hbmqtt_pub --url mqtt://guest:test@iot.codelab.club -t "/scratch3_sub" -m "hello from hbmqtt_pub"
    hbmqtt_sub --url mqtt://guest:test@iot.codelab.club -t "/scratch3_pub"
'''
import logging
import asyncio

from hbmqtt.client import MQTTClient, ClientException
from hbmqtt.mqtt.constants import QOS_0

username = "guest"
password = "test"
mqtt_url = "mqtt://{}:{}@iot.codelab.club".format(username, password)

async def uptime_coro():
    C = MQTTClient() # clientid?
    await C.connect(mqtt_url)
    # Subscribe to '$SYS/broker/uptime' with QOS=1
    # Subscribe to '$SYS/broker/load/#' with QOS=2
    await C.subscribe([
            ('/scratch3_pub', QOS_0),
         ])
    try:
        while True:
            message = await C.deliver_message()
            topic = message.topic
            payload = message.data.decode()
            print("%s => %s" % (topic, payload))
        await C.unsubscribe(['/scratch3_sub'])
        await C.disconnect()
    except ClientException as ce:
        logging.error("Client exception: %s" % ce)

if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(uptime_coro())