mqtt_sub.py

import paho.mqtt.client as mqttClient
import time

def on_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to broker")
        global Connected                #Use global variable
        Connected = True                #Signal connection
    else:
        print("Connection failed")
def on_message(client, userdata, message):
    print "Topic: " + message.topic
    print "Message: " + message.payload + "\n"

Connected = False   #global variable for the state of the connection

broker_address= "IPADDRESSOFYOURBROKER"  #Broker address
port = 1883                         #Broker port
user = "yourUser"                    #Connection username
password = "yourPassword"            #Connection password

client = mqttClient.Client("SOMENAMEFORYOURCLIENT")               #create new instance
client.username_pw_set(user, password=password)    #set username and password
client.on_connect= on_connect                      #attach function to callback
client.on_message= on_message                      #attach function to callback
client.connect(broker_address, port=port)          #connect to broker
client.loop_start()        #start the loop

while Connected != True:    #Wait for connection
    time.sleep(0.1)

client.subscribe([("sometopic/#", 0), ("someothertopic/#", 0) ])

try:
    while True:
        time.sleep(1)

except KeyboardInterrupt:
    print "exiting"
    client.disconnect()
    client.loop_stop()