Trying to make a simple MQTT broker connection (mqtt_as)

[nastiliano]

Hello everybody.

I'm using the @peterhinch libraries and his example to make a simple connection with my "Hive MQ" broker cluster (adding Hive MQ particularities) and it doesn't work:

 from mqtt_as import MQTTClient, config
 import asyncio

#Local configuration
config["ssid"] = "my_ssid"  # Optional on ESP8266
config["wifi_pw"] = "my_pass"
config["user"] = "my_user"
config["password"] = "my_pass"
config["client_id"] = "a_client_id"
broker = "xxx.s2.eu.hivemq.cloud"
config["server"] = broker
config["port"] = 0
config["ssl"] = True
config["ssl_params"] = {"server_hostname": broker , }


def callback(topic, msg, retained):
    print((topic, msg, retained))

async def conn_han(client):
    await client.subscribe('foo_topic', 1)

async def main(client):
    await client.connect()
    n = 0
    while True:
        await asyncio.sleep(5)
        print('publish', n)
        # If WiFi is down the following will pause for the duration.
        await client.publish('result', '{}'.format(n), qos = 1)
        n += 1

config['subs_cb'] = callback
config['connect_coro'] = conn_han

MQTTClient.DEBUG = True  # Optional: print diagnostic messages
client = MQTTClient(config)
try:
    asyncio.run(main(client))
finally:
    client.close()  # Prevent LmacRxBlk:1 errors

Somebody could help me?

Thanks. Merry christmas to everyone.

[2dof]

I usually connect to hivemq like in example below ("My example:") based on example/tutorial fromot-reading-sensor-data-raspberry-pi-pico and then run node-red to visualising data.
If you subscribe then ensure that client (broker) subscribe (send data back), I usually test first all "manually" form node-red.

also wy await in await client.publish('result', '{}'.format(n), qos = 1) in loop when you have await asyncio.sleep(5) in while loop ( ...sleep(5) should be at the end while loop)

see some other example ( not asnychio) with mosquito as broker on local machine (your laptop) (it help (at least in my case) to faster design and test code and then easy way to switch to hivemq micropython-mqtt-esp32-esp8266

My example:

def connectMQTT():
    client = MQTTClient(
    client_id=b"l<client_name>",
    server=<server_adres>    #b"da375fb.........92bf6d.eu.hivemq.cloud",
    port=8883,                   # port No defined in hivemq.cloud (ussualu 8883)
    user=<user name> ,     #                   
    password=<password do server(cluster)>,
    keepalive=120,
    ssl=True,
    ssl_params={'server_hostname':'da233fb2......2bf6c.s2.eu.hivemq.cloud'}
    )
    client.connect()
    return client


client = connectMQTT()

async def publish(topic, value):    # ensure than you have connection with client

  while True:
       print(topic)
       print(value)
       client.publish(topic, value)
       print("publish Done")
       await asyncio.sleep(1) 

# do any async work in main app ......

[nastiliano]

Hello,

Thanks, but for me is the same.
It doesn't work

Best regards.

[peterhinch]

The code looks OK to me. When you say it doesn't work, what happens? Please provide the traceback.

The advice from @2dof to test manually is good. I use mosquitto_pub and mosquitto_sub to prove I can access a broker before trying with mqtt_as.

[peterhinch]

It's failing on the DNS lookup:

self._addr = socket.getaddrinfo(self.server, self.port)[0][-1]

.server is the entry in config["server"] and .port is 1883 unless you're using SSL in which case 8883. These are the standard ports for MQTT. Either the config entry is wrong or there is something amiss with DNS lookup on your network.

[nastiliano]

Ok, changing this it worked (public broker):

# Local configuration
config['ssid'] = 'mySSID'  # Optional on ESP8266
config['wifi_pw'] = 'mypass'
config['server'] = 'broker.hivemq.com'  # HiveMQ

But in private broker:

# Local configuration
config['ssid'] = 'mySSID'  # Optional on ESP8266
config['wifi_pw'] = 'mypass'
config['server'] = 'xxxxxxxxxxxxxxxxxxxxx.s2.eu.hivemq.cloud'  # Change to suit e.g. 'iot.eclipse.org'
config['ssl'] = True
config['user'] = 'user'
config['password'] = 'pass'

Or even this:

# Local configuration
config['ssid'] = 'mySSID'  # Optional on ESP8266
config['wifi_pw'] = 'mypass'
config['server'] = 'xxxxxxxxxxxxxxxxxxxxx.s2.eu.hivemq.cloud'  # Change to suit e.g. 'iot.eclipse.org'
config['ssl'] = True
config['ssl_params'] = {"server_hostname": 'xxxxxxxxxxxxxxxxxxxxx.s2.eu.hivemq.cloud'}
config['user'] = 'user'
config['password'] = 'pass'

Fails, the error is always the same:

Traceback (most recent call last):
File "<stdin>", line 37, in <module>
File "asyncio/core.py", line 1, in run
File "asyncio/core.py", line 1, in run_until_complete
File "asyncio/core.py", line 1, in run_until_complete
File "<stdin>", line 22, in main
File "mqtt_as.py", line 645, in connect
File "mqtt_as.py", line 280, in _connect
OSError: [Errno 113] ECONNABORTED

I think another parameter is missing...
Any ideas?

Thanks

[nastiliano]

Definitively,

Only works with public brokers...

I tried with "EMQX" too and the error is exactly the same.

Could you help me, please?

Thanks

[zcattacz]

If the server is kicking your device off, you need to read your broker service's documentation more carefully, it's not a client code issue. Make sure your client and broker setup is correct. Logon limit of identical credential is only one common limit of all possible limits.

[nastiliano]

Hello,

Finally after read a lot and a lot...

I installed "Mosquitto" in my own "VPS" and it works great, only using credentials without TLS certificates, because it's a nightmare.

Thank you very much and happy new year.