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. YOUR-BROKER.YOUR-NAMESPACE.cloudflarepubsub.com 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 pubsub.py with the following content, and use python3 pubsub.py to run the example:

# Install the library via: pip install paho-mqtt

import osimport paho.mqtt.client as mqttimport 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))    ctx.subscribe(topic)    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    client.disconnect()

# Specify MQTT broker FQDN: <broker name>.<namespace>.cloudflarepubsub.comfqdn = 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 APIusername = "anything"password = check_env(os.environ.get("BROKER_TOKEN")).strip("\"")

# Specify a topic name to subscribe to and publish ontopic = check_env(os.environ.get("BROKER_TOPIC"))

# Create the MQTT clientclient = mqtt.Client(client_id="", protocol=mqtt.MQTTv5)

# Set username & passwordclient.username_pw_set(username, password)

# Enable TLSclient.tls_set()

# Connect to your broker and register callback functionsclient.connect(fqdn, 8883)client.on_connect = on_connectclient.on_message = on_message
# Wait until we have received our messageclient.loop_forever()