API Gateway

A robust and scalable API Gateway service for the LMS Microservices ecosystem, providing centralized request routing, authentication, rate limiting, and service orchestration.

📋 Table of Contents

• Overview
• Features
• Tech Stack
• Prerequisites
• Installation
• Configuration
• Usage
• API Documentation
• Architecture
• Contributing
• License

🎯 Overview

The API Gateway serves as the single entry point for all client requests in the LMS microservices architecture. It handles cross-cutting concerns such as authentication, request routing, rate limiting, and load balancing, allowing individual microservices to focus on their core business logic.

✨ Features

• Request Routing: Intelligent routing of requests to appropriate microservices
• Authentication & Authorization: JWT-based authentication and role-based access control
• Rate Limiting: Configurable rate limiting to prevent service abuse
• Request/Response Transformation: Header manipulation and payload transformation
• Service Discovery: Dynamic service discovery and load balancing
• Monitoring & Logging: Comprehensive request/response logging and metrics collection
• Circuit Breaker: Automatic failure detection and circuit breaking
• API Versioning: Support for multiple API versions
• CORS Support: Configurable Cross-Origin Resource Sharing

🛠 Tech Stack

• Language: Java
• Framework: Spring Cloud Gateway / Spring Boot
• Service Discovery: Eureka / Consul (configurable)
• Authentication: JWT
• Monitoring: Spring Boot Actuator, Micrometer, Prometheus
• Containerization: Docker
• Orchestration: Kubernetes (optional)

📦 Prerequisites

• Java 11 or higher
• Maven 3.6+ or Gradle 6.0+
• Docker (for containerized deployment)
• Service Registry (Eureka/Consul)

🚀 Installation

Clone the Repository

git clone https://github.com/lms-microservices/api-gateway.git
cd api-gateway

Build the Project

Using Maven:

mvn clean install

Using Gradle:

gradle clean build

Build Docker Image

docker build -t lms-microservices/api-gateway:latest .

⚙️ Configuration

Environment Variables

Create a .env file or set the following environment variables:

# Server Configuration
SERVER_PORT=8080
SERVER_SERVLET_CONTEXT_PATH=/

# Service Registry
EUREKA_CLIENT_SERVICE_URL_DEFAULTZONE=http://localhost:8761/eureka
SERVICE_REGISTRY_TYPE=eureka  # or 'consul'

# Authentication
JWT_SECRET=your-secret-key-here
JWT_EXPIRATION=3600000

# Rate Limiting
RATE_LIMIT_ENABLED=true
RATE_LIMIT_REQUESTS=1000
RATE_LIMIT_WINDOW=60

# Logging
LOGGING_LEVEL_ROOT=INFO
LOGGING_LEVEL_COM_LMS_MICROSERVICES=DEBUG

Application Configuration

Edit application.yml or application.properties:

spring:
  application:
    name: api-gateway
  cloud:
    gateway:
      routes:
        - id: users-service
          uri: lb://users-service
          predicates:
            - Path=/api/v1/users/**
        - id: courses-service
          uri: lb://courses-service
          predicates:
            - Path=/api/v1/courses/**
      globalcors:
        corsConfigurations:
          '[/**]':
            allowedOrigins: "*"
            allowedMethods: GET, POST, PUT, DELETE, OPTIONS
            allowedHeaders: "*"

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

📖 Usage

Starting the Service

Local development:

mvn spring-boot:run

Using Docker:

docker run -p 8080:8080 --env-file .env lms-microservices/api-gateway:latest

Kubernetes deployment:

kubectl apply -f k8s/

Health Check

curl http://localhost:8080/actuator/health

Available Endpoints

• GET /actuator/health - Service health status
• GET /actuator/metrics - Application metrics
• GET /swagger-ui.html - API documentation (if Swagger enabled)

🏛️ Architecture

┌─────────────────┐
│   Clients       │
└────────┬────────┘
         │ HTTP/REST
         ▼
┌─────────────────────────┐
│   API Gateway           │
│ ┌─────────────────────┐ │
│ │ Authentication      │ │
│ │ Rate Limiting       │ │
│ │ Request Routing     │ │
│ │ Load Balancing      │ │
│ └─────────────────────┘ │
└────────┬────────────────┘
         │
    ┌────┴────┬──────────┬──────────┐
    ▼         ▼          ▼          ▼
┌────────┐ ┌──────┐  ┌────────┐ ┌──────┐
│ Users  │ │Course│  │Payments│ │Notify│
│Service │ │Service  │Service │ │Service
└────────┘ └──────┘  └────────┘ └──────┘

🤝 Contributing

We welcome contributions! Please follow these steps:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Development Guidelines

• Follow Google Java Style Guide
• Write unit tests for new features (minimum 80% coverage)
• Ensure all tests pass: mvn clean test
• Update documentation as needed

📝 License

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

📧 Support

For support and questions, please open an issue in the repository or contact the development team at support@lms-microservices.dev.

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Last Updated: April 29, 2026
Maintained By: LMS Microservices Team