MQTT Connector

Overview

The MQTT connector enables publish/subscribe messaging for IoT devices using MQTT v3 protocol.

Connector Types:

• MqttV3Reader - Subscribe to MQTT topics
• MqttV3Writer - Publish to MQTT topics

MQTT Reader

Subscribe to MQTT topics and receive messages:

{
  "type": "MqttV3Reader",
  "config": {
    "endpoint": "localhost:1883",
    "topic": "sensors/temperature",
    "qos": 0,
    "clientId": "meddle-reader"
  }
}

With Authentication

{
  "type": "MqttV3Reader",
  "config": {
    "endpoint": "mqtt.example.com:1883",
    "topic": "factory/sensors/#",
    "qos": 1,
    "clientId": "meddle-reader",
    "username": "mqtt_user",
    "password": "mqtt_password"
  }
}

MQTT Writer

Publish messages to MQTT topics:

{
  "type": "MqttV3Writer",
  "config": {
    "endpoint": "localhost:1883",
    "topic": "data/output",
    "qos": 0,
    "clientId": "meddle-writer"
  }
}

Configuration Parameters

• endpoint: MQTT broker address (host:port)
• topic: Topic to subscribe/publish (supports wildcards for reader: +, #)
• qos: Quality of Service (0, 1, or 2)
• clientId: Unique client identifier
• username: (Optional) MQTT username
• password: (Optional) MQTT password

QoS Levels

• 0: At most once (fire and forget)
• 1: At least once (acknowledged delivery)
• 2: Exactly once (assured delivery)

Topic Wildcards (Reader Only)

• +: Single level wildcard (sensors/+/temperature)
• #: Multi-level wildcard (sensors/#)

Related Connectors

• HTTP - REST API alternative
• Filter - Filter MQTT messages