Microservices Architecture (MSA-Upgraded) Project

A comprehensive microservices architecture implementation using Spring Boot, Spring Cloud, and related technologies.

Overview

This project demonstrates a complete microservices ecosystem with service discovery, configuration management, API gateway, distributed tracing, and security features.

Architecture Components

Microservices Architecture Flow Diagram

System Architecture Overview

Core Services

• Employee Service - Manages employee information and operations
• Employee Payroll Service - Handles payroll calculations and management
• Role Service - Manages user roles and permissions

Infrastructure Services

• Eureka Naming Server - Service discovery and registration
• Spring Cloud Config Server - Centralized configuration management
• Spring Cloud Gateway Server - API gateway for routing and load balancing
• Micrometer Tracing - Distributed tracing and monitoring

Technology Stack

• Java 17
• Spring Boot 3.2.5
• Spring Cloud 2023.0.1
• Gradle - Build tool and dependency management
• H2 Database - In-memory database for development
• Eureka - Service discovery
• Spring Cloud Gateway - API gateway
• Micrometer Tracing - Distributed tracing
• Spring Security - Authentication and authorization
• Resilience4j - Circuit breaker pattern
• SpringDoc OpenAPI - API documentation

Technology Stack Diagram

Project Structure

msa-upgraded/
├── build.gradle                      # Parent build configuration
├── settings.gradle                   # Gradle settings
├── README.md                         # This file
├── employee-payroll-service/         # Payroll management service
├── employee-service/                 # Employee management service
├── eureka-naming-server/             # Service discovery server
├── role-service/                     # Role management service
├── spring-cloud-config-server/       # Configuration server
├── micrometer-tracing/               # Distributed tracing server
└── spring-cloud-gateway-server/      # API gateway

Data Flow Diagram

Quick Start

Prerequisites

• Java 17 or higher
• Gradle 8.0 or higher (or use provided wrapper)

Building the Project

# Build all modules
./gradlew clean build

# Build specific module
./gradlew :employee-service:clean :employee-service:build

# Skip tests during build
./gradlew clean build -x test

Gradle Build System Architecture

Running Services

1. Start Infrastructure Services (in order):

   # Start Eureka Server
   cd eureka-naming-server
   ../gradlew bootRun
   
   # Start Config Server
   cd ../spring-cloud-config-server
   ../gradlew bootRun
   
   # Start Tracing (optional)
   cd ../micrometer-tracing
   ../gradlew bootRun

2. Start Business Services:

   # Start Employee Service
   cd ../employee-service
   ../gradlew bootRun
   
   # Start Payroll Service
   cd ../employee-payroll-service
   ../gradlew bootRun
   
   # Start Role Service
   cd ../role-service
   ../gradlew bootRun

3. Start Gateway:

   cd ../spring-cloud-gateway-server
   ../gradlew bootRun

Service Endpoints

Once all services are running, you can access:

• Eureka Dashboard: http://localhost:8761
• Spring Cloud Gateway: http://localhost:8765
• Micrometer Tracing Dashboard: http://localhost:9411
• Config Server: http://localhost:8888

Development

Configuration

All services use Spring Cloud Config for centralized configuration. Configuration files are located in the spring-cloud-config-server module.

Database

Services use H2 in-memory database by default. The database console is available at:

• Employee Service: http://localhost:8080/h2-console
• Payroll Service: http://localhost:8081/h2-console
• Role Service: http://localhost:8082/h2-console

Default credentials:

• URL: jdbc:h2:mem:testdb
• Username: sa
• Password: (empty)

Testing

# Run all tests
./gradlew test

# Run tests for specific module
./gradlew :employee-service:test

# Run integration tests
./gradlew check

Monitoring and Tracing

• Micrometer Tracing provides distributed tracing across microservices
• Spring Boot Actuator endpoints expose health and metrics information
• Eureka provides service discovery and health monitoring

API Documentation

Each service exposes RESTful APIs. You can explore the APIs using:

• Swagger UI (if configured)
• Postman collections
• Direct HTTP requests

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Run the test suite
6. Submit a pull request

License

This project is for educational and demonstration purposes.

Support

For questions or issues, please refer to the individual service documentation or create an issue in the repository.