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Connect with Python

Below is an example using the paho.mqtt.python package with the TOKEN authentication mode configured on a Broker.

The example below creates a simple subscriber, sends a message to the configured topic, and waits until the message is received before exiting.

Make sure to set environmental variables for the following before running the example:

  • BROKER_FQDN - e.g. without the port or mqtts:// scheme
  • BROKER_TOKEN (a valid auth token)
  • BROKER_TOPIC - e.g. test/topic or hello/world

The example below uses Python 3.8, but should run on Python 3.6 and above.

# Ensure you have paho-mqtt installed
$ pip3 install paho-mqtt

Create a file called with the following content, and use python3 to run the example:

# Install the library via: pip install paho-mqtt
import os
import paho.mqtt.client as mqtt
import sys
# Making sure all environment variables are set
def check_env(env):
if env is None:
sys.exit("BROKER_FQDN, BROKER_TOKEN and BROKER_TOPIC must be set.")
return env
# The callback for when the client receives a CONNACK response from the server.
def on_connect(ctx, userdata, flags, rc, properties):
print("connected to {}".format(ctx._host))
client.publish(topic, "Hello from Python and Pub/Sub!")
# The callback for when a PUBLISH message is received from the server.
def on_message(ctx, userdata, msg):
print("{}: {}".format(msg.topic, msg.payload))
# Good-Bye
# Specify MQTT broker FQDN: <broker name>.<namespace>
fqdn = check_env(os.environ.get("BROKER_FQDN"))
# Any username and your token from the /brokers/YOUR_BROKER/credentials endpoint
# The token should be the base64-encoded JWT issued by the Pub/Sub API
username = "anything"
password = check_env(os.environ.get("BROKER_TOKEN")).strip("\"")
# Specify a topic name to subscribe to and publish on
topic = check_env(os.environ.get("BROKER_TOPIC"))
# Create the MQTT client
client = mqtt.Client(client_id="", protocol=mqtt.MQTTv5)
# Set username & password
client.username_pw_set(username, password)
# Enable TLS
# Connect to your broker and register callback functions
client.connect(fqdn, 8883)
client.on_connect = on_connect
client.on_message = on_message
# Wait until we have received our message