A production-grade distributed task processing system built using Spring Boot, RabbitMQ, and MySQL.

This project showcases event-driven microservices architecture, focusing on asynchronous processing, fault tolerance, scalability, and reliable message delivery using industry-standard design patterns.

• Handles client task submissions
• Persists tasks in MySQL
• Implements Outbox Pattern for reliable event publishing

• Consumes messages from RabbitMQ
• Executes tasks asynchronously
• Handles retries, failures, and logging

• Decouples services via asynchronous messaging
• Supports:
  • Task Queue
  • Retry Queue (TTL-based delay)
  • Dead Letter Queue (DLQ)

Client → API → DB → Outbox → RabbitMQ → Worker → DB
                                      ↓
                                 Retry Queue
                                      ↓
                                    DLQ

• Asynchronous task processing using RabbitMQ
• Microservices-based architecture
• Reliable event publishing via Outbox Pattern

• Configurable retry mechanism
• Delayed retries using TTL queues
• Dead Letter Queue (DLQ) for failed processing
• Idempotent processing using DB-level safeguards

• Create and manage tasks
• Retrieve task by ID
• Pagination support
• Filter tasks by status

• Centralized exception handling
• Request validation
• Structured API error responses

POST /tasks

{
  "title": "Process Order",
  "description": "Order ID 123"
}

{
  "id": 1,
  "status": "PENDING"
}

PENDING → PROCESSING → COMPLETED
                 ↓
              FAILED → RETRY → DLQ

api-service/
  └── Handles task submission and persistence

worker-service/
  └── Processes tasks asynchronously

docs/
  └── Contains architecture diagrams

postman/
  └── API collections (optional)

• Used RabbitMQ for decoupled asynchronous communication
• Implemented Outbox Pattern to ensure consistency between DB and messaging
• Used DLQ for handling failed messages safely
• Applied idempotency to prevent duplicate processing
• Designed system for horizontal scalability

• Language: Java 21
• Backend: Spring Boot
• Database: MySQL
• Messaging: RabbitMQ
• ORM: Spring Data JPA
• Build Tool: Gradle

• Java 21+
• MySQL
• RabbitMQ

# Start API Service
cd api-service
./gradlew bootRun

# Start Worker Service
cd worker-service
./gradlew bootRun

• Distributed Systems Design
• Event-Driven Architecture
• Outbox Pattern
• Retry & Failure Handling
• Dead Letter Queue (DLQ)
• Idempotent Processing
• Pagination & Filtering
• Exception Handling

• Docker & Containerization
• API Gateway Integration
• JWT Authentication & Security
• Monitoring (Prometheus, Grafana)
• Database Migration (Flyway)

This project reflects real-world backend engineering practices:

• Handles high-scale asynchronous workloads
• Ensures data consistency & reliability
• Demonstrates microservices communication patterns
• Designed with production-grade architecture principles

Pushpak A. Fasate