🐰 RabbitMQ Dead Letter Queue Demo Project

Welcome to the RabbitMQ Dead Letter Queue Demo Project! This project is a minimalist yet professional implementation of RabbitMQ with Dead Letter Queues (DLQ) in a Spring Boot application. It's designed to showcase best practices and provide a solid foundation for your messaging needs.

🚀 Getting Started

Follow this guide to set up, run, and test the project on your local machine.

📋 Table of Contents

• Prerequisites
• Installation
• Project Structure
• Running the Application
• Testing the API
  • Send a Message
  • Dead Letter Queue Behavior

📋 Prerequisites

Before you begin, ensure you have the following installed:

• Java JDK 11 or higher
• Maven 3.6 or higher
• RabbitMQ Server (with the Management Plugin enabled)
• Git (optional, for cloning the repository)

🛠️ Installation

1. Clone the repository (or download the source code):

   git clone https://github.com/Ces107/RabbitMQ-dead-letter-queue-test-/

2. Build the project using Maven:

   mvn clean install

📂 Project Structure

Here's an overview of the key files and directories in the project:

rabbitmq-dlq-demo/
├── src/
│   ├── main/
│   │   ├── java/com/cesar/demodelrabbit/
│   │   │   ├── App.java                  # Main application class
│   │   │   ├── DTO.java                  # Data Transfer Object
│   │   │   ├── Controller.java           # REST Controller
│   │   │   ├── Sender.java               # Message Sender Service
│   │   │   ├── listener/
│   │   │   │   └── Listener.java         # Message Listener
│   │   │   └── rabbit/
│   │   │       └── RabbitMQConfiguration.java  # RabbitMQ Configuration
│   │   └── resources/
│   │       └── application.properties    # Application properties
├── pom.xml                               # Maven configuration
└── README.md                             # This README file

▶️ Running the Application

1. Start RabbitMQ Server

Ensure that the RabbitMQ server is running on your local machine. By default, it runs on localhost:5672 for AMQP and localhost:15672 for the Management UI.

2. Run the Spring Boot Application

You can run the application using Maven or your IDE.

• Using Maven:

  mvn spring-boot:run

• Using Java:

  java -jar target/rabbitmq-dlq-demo-0.0.1-SNAPSHOT.jar

• Using Your IDE:

  Import the project into your IDE and run the App.java class.

🧪 Testing the API

The application exposes a RESTful API to send messages, which are then processed by RabbitMQ.

📍 Base URL

http://localhost:8080

1. Send a Message

Endpoint: /send

Method: POST

Content-Type: application/json

Request Body Example

{
  "title": "Test Message",  
  "content": "This is a test message",
  "id": "42"
}

If title = "error" it will produce a Exception in receiver:

{
  "title": "error",  
  "content": "This is a test error message",
  "id": "1337"
}

cURL Command

curl -X POST   http://localhost:8080/send   -H 'Content-Type: application/json'   -d '{
    "title": "Test Message",
    "content": "This is a test message",
    "id": "12345"
}'

Response

Mensaje enviado

2. Dead Letter Queue Behavior

The application is configured to simulate an error during message processing, causing the message to be sent to the Dead Letter Queue.

Simulating Message Failure

In the Listener.java class, an exception is thrown to simulate a processing error:

throw new Exception("Error processing the message");

Expected Behavior

• The message is sent to the main queue (app.queue).
• The listener receives the message and throws an exception.
• The message is rejected and routed to the Dead Letter Queue (app.queue.deadletter).
• The message can be inspected in RabbitMQ's Management UI under the Dead Letter Queue.