Gossiper

gossiper is a lightweight Go package designed to simplify working with environment variables, RabbitMQ, and validation tools. It streamlines the process of managing configurations and consuming messages from RabbitMQ dynamically.

Installation

go get github.com/pieceowater-dev/lotof.lib.gossiper

Usage

Instead of placing the entire configuration inside main.go, it's better to separate the configuration into its own file and import it in main.go. This helps keep the code organized, especially as the application grows.

Step 1: Create a Config File

Create a file named config.go where you can define the configuration for the environment variables and RabbitMQ consumers.

package main

import "github.com/pieceowater-dev/lotof.lib.gossiper"

func GetConfig() gossiper.Config {
	return gossiper.Config{
		Env: gossiper.EnvConfig{
			Required: []string{"RABBITMQ_DSN"},
		},
		AMQPConsumer: gossiper.AMQPConsumerConfig{
			DSNEnv: "RABBITMQ_DSN",
			Queues: []gossiper.QueueConfig{
				{
					Name:       "template_queue",
					Durable:    true,
					AutoDelete: false,
					Exclusive:  false,
					NoWait:     false,
					Args:       nil,
				},
			},
			Consume: []gossiper.AMQPConsumeConfig{
				{
					Queue:     "template_queue",
					Consumer:  "example_consumer",
					AutoAck:   true,
					Exclusive: false,
					NoLocal:   false,
					NoWait:    false,
					Args:      nil,
				},
			},
		},
	}
}

Step 2: Import Config into main.go

Now, in your main.go, import the configuration and use it in the gossiper.Setup function.

package main

import (
	"encoding/json"
	"github.com/pieceowater-dev/lotof.lib.gossiper"
	"log"
)

func HandleMessage(msg gossiper.AMQMessage) any {
	log.Printf("Received message: %s", msg.Pattern)
	return "OK"
}

func main() {
	// Import the configuration from config.go
	conf := GetConfig()

	// Initialize and start the consumers
	gossiper.Setup(conf, nil, func(msg []byte) any {
		var customMessage gossiper.AMQMessage
		err := json.Unmarshal(msg, &customMessage)
		if err != nil {
			log.Println("Failed to unmarshal custom message:", err)
			return nil
		}
		return HandleMessage(customMessage)
	})

	log.Println("Application started")
}

Configuration

gossiper.Config

This struct is the core configuration and includes:

• EnvConfig: Manages environment variables.
• AMQPConsumerConfig: Configures RabbitMQ consumers.

EnvConfig

type EnvConfig struct {
    Required []string
}

• Required ([]string): Specifies a list of environment variables that are mandatory for the application to run. If any variable is missing, the application will return an error.

AMQPConsumerConfig

type AMQPConsumerConfig struct {
    DSNEnv  string
    Queues  []QueueConfig
    Consume []AMQPConsumeConfig
}

• DSNEnv (string): The environment variable name that stores the RabbitMQ DSN (Data Source Name). This value is retrieved from the environment.
• Queues ([]QueueConfig): A list of queues that should be declared in RabbitMQ. Each queue has its own configuration.
• Consume ([]AMQPConsumeConfig): Defines the consumers and how they should consume messages from RabbitMQ.

QueueConfig

type QueueConfig struct {
    Name       string
    Durable    bool
    AutoDelete bool
    Exclusive  bool
    NoWait     bool
    Args       amqp.Table
}

• Name (string): The name of the RabbitMQ queue.
• Durable (bool): If true, the queue will survive broker restarts.
• AutoDelete (bool): If true, the queue will be automatically deleted when the last consumer disconnects.
• Exclusive (bool): If true, the queue can only be used by the current connection and will be deleted when the connection is closed.
• NoWait (bool): If true, the server will not respond to the queue declaration. The client won’t wait for confirmation that the queue was created.
• Args (amqp.Table): Custom arguments to pass when creating the queue. Usually nil.

AMQPConsumeConfig

type AMQPConsumeConfig struct {
    Queue     string
    Consumer  string
    AutoAck   bool
    Exclusive bool
    NoLocal   bool
    NoWait    bool
    Args      amqp.Table
}

• Queue (string): The name of the queue to consume from.
• Consumer (string): The consumer tag to identify this consumer.
• AutoAck (bool): If true, messages will be automatically acknowledged after being delivered. Otherwise, manual acknowledgment is required.
• Exclusive (bool): If true, the queue can only be consumed by this consumer.
• NoLocal (bool): If true, messages published on this connection are not delivered to this consumer (rarely used).
• NoWait (bool): If true, the server will not send a response to the consumer setup request.
• Args (amqp.Table): Additional arguments for consumer setup.

Example .env file

RABBITMQ_DSN=amqp://guest:guest@localhost:5672/

Logging

gossiper logs every message received and any errors encountered during message unmarshalling.

Contributing

Contributions are welcome! Feel free to submit issues or pull requests to improve the package or its documentation.

---

With gossiper, managing RabbitMQ consumers and environment variables in Go projects becomes more straightforward. Enjoy using it!

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

PCWT Dev