Microservices Architecture with API Gateway, Eureka, Auth, User, Product Services, and Common Module

This project implements a microservices architecture using Spring Boot and Spring Cloud. It consists of the following components:

• API Gateway: Routes and filters incoming requests.
• Auth Service: Handles user authentication and issues JWT tokens.
• User Service: Manages user data.
• Product Service: Manages products and catalogs.
• Eureka Server: Service discovery and registration.
• Common Module: A shared library containing reusable classes (DTOs, utilities, exceptions, constants).

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🗺️ Architecture Overview

📦 Common Module

• Purpose: Provides shared components and reduces code duplication.
• Used by: Auth, User, and Product services.
• Contents:
  • DTOs (Data Transfer Objects)
  • Custom Exceptions
  • Response Models (e.g., ApiResponse)
  • Enums & Constants
  • Utility Classes (e.g., JWT utility)

Usage

Each service includes the common module as a dependency:

<dependency> 
  <groupId>com.commonModule</groupId>
	<artifactId>commonModule</artifactId>
	<version>0.0.1-SNAPSHOT</version>
</dependency>

🛡️ Microservice Authentication System

This project implements a secure microservice-based architecture using JWT for authentication, Spring Cloud Gateway for routing, and Eureka for service discovery.

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🔐 Authentication Flow

1. Login
   Clients send a POST /api/auth/login request with user credentials.

2. Token Issuance
   The Auth Service validates the credentials and issues a JWT token.

3. Authorization
   Clients include the token in the Authorization: Bearer <token> header for secure endpoints.

4. Gateway Validation
   The API Gateway verifies the JWT token before forwarding the request to internal services.

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🌐 API Gateway

• Base URL Prefix: /api/**
• Responsibilities:
  • Route external requests to internal services
  • Validate JWT tokens for secure endpoints

🔁 Routes

Route Prefix	Service
/api/auth/**	Auth Service
/api/users/**	User Service
/api/products/**	Product Service

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🧾 Auth Service

• Endpoints:

  • POST /auth/login – Authenticate user and return JWT token
  • POST /auth/register – Register a new user

• Uses:

  • Common DTOs and exception handling from commonmodule

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👤 User Service

• Endpoints:

  • GET /users/{id} – Retrieve user by ID
  • PUT /users/{id} – Update user details

• Uses:

  • DTOs, ApiResponse, and shared exceptions from commonmodule

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📦 Product Service

• Endpoints:

  • GET /products – List all products
  • POST /products – Add a new product

• Uses:

  • Shared models and exception handling from commonmodule

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🔍 Eureka Server

• URL: http://localhost:8761/

Configuration

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/