Gokit MQTT

The mqtt package provides a robust and idiomatic implementation for working with MQTT brokers in Go. It includes features for publishing, subscribing, and managing MQTT connections, while adhering to Go best practices.

Features

• Client Management: Establish and manage connections to MQTT brokers.
• Publishing: Publish messages to topics with or without context deadlines.
• Subscription Management: Register and consume messages from topics.
• Error Handling: Comprehensive error handling for common MQTT operations.
• Tracing: Integrated with OpenTelemetry for distributed tracing.

Installation

To use the mqtt package, add it to your project:

go get github.com/ralvescosta/gokit/mqtt

Usage

Creating an MQTT Client

import (
	"github.com/ralvescosta/gokit/mqtt"
    configsBuilder "github.com/ralvescosta/gokit/configs_builder"
)

func main() {
	cfgs, err := configsBuilder.
		NewConfigsBuilder().
		MQTT().
		Build()
	if err != nil {
		cfgs.Logger.Fatal(err.Error())
	}

	client := mqtt.NewMQTTClient(cfgs)

	if err := client.Connect(); err != nil {
		panic(err)
	}

	defer client.Client().Disconnect(250)
}

Publishing Messages

With Context Deadline

import (
	"context"
	"github.com/ralvescosta/gokit/mqtt"
)

func publishWithContext(publisher mqtt.Publisher) {
	ctx := context.Background()
	err := publisher.PubCtx(ctx, "example/topic", mqtt.AtLeastOnce, "Hello, MQTT!")
	if err != nil {
		panic(err)
	}
}

Without Context Deadline

func publishWithoutContext(publisher mqtt.Publisher) {
	err := publisher.Pub("example/topic", mqtt.AtLeastOnce, "Hello, MQTT!")
	if err != nil {
		panic(err)
	}
}

Subscribing to Topics

import (
	"os"
	"github.com/ralvescosta/gokit/mqtt"
)

func subscribe(dispatcher mqtt.Dispatcher) {
	handler := func(ctx context.Context, topic string, qos mqtt.QoS, payload []byte) error {
		fmt.Printf("Received message on topic %s: %s\n", topic, string(payload))
		return nil
	}

	err := dispatcher.Register("example/topic", mqtt.AtLeastOnce, handler)
	if err != nil {
		panic(err)
	}

	stop := make(chan os.Signal, 1)
	dispatcher.ConsumeBlocking(stop)
}

Error Handling

The mqtt package provides predefined errors for common issues:

• ConnectionFailureError: Indicates a failure to connect to the MQTT broker.
• EmptyTopicError: Indicates that the topic for a subscription cannot be empty.
• NillHandlerError: Indicates that the handler for a subscription cannot be nil.
• NillPayloadError: Indicates that the payload for a publish operation cannot be nil.
• InvalidQoSError: Indicates that the provided QoS value is invalid.

Tracing

The mqtt package integrates with OpenTelemetry for distributed tracing. Each message handler creates a new span with the topic name as the span name.

License

This package is licensed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are welcome! Please read the contributing guidelines before submitting a pull request.

Support

For support, please open an issue in the repository or contact the maintainers.