Examples

This guide should help you connect and consume messages from your computer vision filter.

Python Example

Python

In this guide we are using the Paho MQTT client in Python.

Prerequisites

• Paho MQTT library installed:

  pip install paho-mqtt

Sample Integration for Consuming Messages

1. Import the Paho MQTT library

import paho.mqtt.client as mqtt
import json

2. Set up MQTT client

# Replace 'your_device_id' and 'your_filter_id' with actual device and filter identifiers.
device_id = 'your_device_id'
filter_id = 'your_filter_id'

client = mqtt.Client(client_id=f"{device_id}_{filter_id}")

3. Define Connection Parameters

broker_address = '<BROKER_IP>'
broker_port = <BROKER_PORT>
client.connect(broker_address, port=broker_port)

4. Subscribe to Relevant Topics

# Subscribe to data output from the filter
client.subscribe(f"device/{device_id}/filter/{filter_id}/data")

# Subscribe to status updates from the filter
client.subscribe(f"device/{device_id}/filter/{filter_id}/status")

5. Implement Callbacks for Incoming Messages

def on_message(client, userdata, msg):
    topic = msg.topic
    payload = msg.payload.decode("utf-8")
    
    if "data" in topic:
        # Process incoming data from the filter
        print(f"Received data on topic {topic}: {payload}")
        # Add your custom logic for handling data messages
    elif "status" in topic:
        # Handle status updates from the filter
        print(f"Received status on topic {topic}: {payload}")
        # Add your custom logic for handling status messages

# Set callback for incoming messages
client.on_message = on_message

6. Loop to Handle Messages

client.loop_start()

7. Keep the Script Running

try:
    while True:
        pass
except KeyboardInterrupt:
    # Disconnect from the broker when done
    client.loop_stop()
    client.disconnect()

Additional Tips

• Adjust QoS levels based on message importance.

• Customize topics and payloads according to your application's needs.

• Explore advanced features like metrics publication based on your naming conventions.