Sprocket MQTT Plugin

A message queuing plugin for the Sprocket framework that provides seamless integration between local Sprocket events and MQTT message brokers.

Overview

The MQTT plugin enables bidirectional communication between Sprocket devices and MQTT message brokers, allowing for distributed IoT applications and cloud integration.

Features

• Bidirectional Communication: Upstream (local → MQTT) and downstream (MQTT → local) message routing
• Automatic Topic Mapping: Seamless integration between local Sprocket topics and MQTT topics
• Configurable Broker Settings: Support for authentication and custom topic roots
• Task-Based Operation: Integrated with Sprocket's task scheduler for reliable operation
• Connection Management: Automatic reconnection with configurable retry limits
• JSON Configuration: Easy setup through JSON configuration files

Configuration

struct MqttConfig {
    const char *clientName;    // Unique client identifier
    const char *brokerHost;    // MQTT broker hostname/IP
    int brokerPort;            // MQTT broker port (usually 1883)
    const char *topicRoot;     // Topic prefix for routing
    const char *user;          // MQTT username (optional)
    const char *pass;          // MQTT password (optional)
};

Message Flow

Upstream (Local → MQTT)

• Local Sprocket events are automatically published to MQTT broker
• Topics are prefixed with the configured topicRoot
• Enables cloud monitoring and logging of device events

Downstream (MQTT → Local)

• MQTT messages are received and routed to local Sprocket topics
• Topic prefixes are stripped for local processing
• Allows remote control and configuration of devices

Usage Example

#include <MqttPlugin.h>
#include <MqttConfig.h>

// Configure MQTT connection
MqttConfig mqttConfig = {
    .clientName = "myDevice",
    .brokerHost = "mqtt.example.com",
    .brokerPort = 1883,
    .topicRoot = "home/device1",
    .user = "username",
    .pass = "password"
};

// Create plugin with bidirectional binding
MqttPlugin mqttPlugin(mqttConfig, true, true);

// Activate plugin
mqttPlugin.activate(scheduler);

Configuration File

The plugin can also be configured via JSON files:

{
    "mqttClientName": "myDevice",
    "mqttBrokerHost": "mqtt.example.com",
    "mqttBrokerPort": 1883,
    "mqttRootTopic": "home/device1",
    "mqttUser": "username",
    "mqttPass": "password"
}

Installation

1. Include the MQTT plugin in your Sprocket project
2. Configure MQTT broker settings
3. Initialize the plugin with your configuration
4. Activate the plugin through the Sprocket scheduler

Dependencies

• Sprocket-Core framework
• Arduino framework
• PubSubClient library
• WiFiClient (ESP8266/ESP32)
• TaskScheduler library

Platform Support

• ESP8266
• ESP32

Examples

See the examples/ directory for complete usage examples:

• basic/ - Basic MQTT setup and communication
• chat/ - Multi-device chat application

Architecture

The plugin creates a bridge between:

• Local Event Channel: Sprocket's internal pub/sub system
• MQTT Broker: External message queue for distributed communication

License

See LICENSE file for details.