MQTT

import paho.mqtt.client as mqtt
import json

def on_connect(client, userdata, flags, rc):
    if   rc==0:
        st.text("Connect successful")
    elif rc==1:
        st.text("incorrect protocol version")
    elif rc==2:
        st.text("invalid client identifier")
    elif rc==3:
        st.text("server unavailable")
    elif rc==4:
        st.text("bad username or password")
    elif rc==5:
        st.text("not authorised")
    elif 6<rc<255:
        st.text("Currently unused")
    else:
        st.text("Connect failed")

def on_log(client, userdata, level, buf):
    st.text("Log: " + buf)

username = "user_name"
password = "xxx"
broker = "host_name"
port = 1883
topic = "my_topic"
client_id = "my_client_name"

client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION1, client_id, transport = "tcp")
client.on_connect = on_connect
client.on_log = on_log
client.username_pw_set(username, password)
client.tls_set()
client.connect(broker, port, keepalive = 10)
#client.subscribe(topic)

publish_result = client.publish(topic, "my message")
st.text(publish_result) # tuple, first number 0 = MQTT_ERR_SUCCESS means messages is successfully sent

client.loop(.1) # needed for on_connect callback to be invoked