paho.mqtt.python unable to pass username and password

Question

I'm trying to create an mqtt connection using paho. After publishing, the rc returns a status of success, however the message has not been delivered.

Here is the code:

import os
import paho.mqtt.client as mqtt
    
def on_connect(client, userdata, flags, rc):
    print("connected with rc: "+str(rc))
    pass
    
def on_publish(client, data, result):
    print("data published")
    pass
    
client = mqtt.Client()
client.username_pw_set(username="test", password="test" )
client.on_connect = on_connect 
client.on_publish = on_publish
client.connect("some-host", 1883)


topic = "/something"
value = "cool"
ret = client.publish(topic, value)

if ret.rc == 0:
    return {
        "statusCode": 200,
        "body": "The payload was successfully published"
    }
else:
    return {
        "statusCode": 500,
        "body": "There was an error publishing this payload"
    }

Does anyone know what's happening here? I saw this post but my issue wasn't resolved by adding client.tls_set() .

Answer 1

Move the publish to the on_connect callback. The code is trying to publish before the connection is finished and add it's a QoS 0 message it's just getting thrown away