Spring Cloud Microservices Architecture

This project demonstrates a microservices architecture using Spring Cloud components, including Eureka Server, API Gateway, User Service, and Spring Boot Admin for monitoring.

Project Structure

• Eureka Server: Service discovery for all microservices.
• API Gateway: Load balancer and request router for microservices.
• User Service: A simple service registered with Eureka Server.
• Spring Boot Admin: Monitoring and managing Spring Boot applications.

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Prerequisites

Before running the project, ensure you have the following installed:

• Java 11 or later
• Maven 3.6+
• Docker (optional, for containerized deployment)

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Setup Instructions

1. Clone the Repository

git clone https://github.com/your-repo/microservices-architecture.git
cd microservices-architecture

2. Build All Services

Build all services using Maven:

mvn clean install

3. Start the Eureka Server

Navigate to the eureka-server directory and run:

cd eureka-server
mvn spring-boot:run

Eureka Server will be available at http://localhost:8761.

4. Start the Spring Boot Admin Server

Navigate to the spring-admin directory and run:

cd spring-admin
mvn spring-boot:run

Spring Boot Admin will be available at http://localhost:9090.

5. Start the API Gateway

Navigate to the api-gateway directory and run:

cd api-gateway
mvn spring-boot:run

API Gateway will be available at http://localhost:8080.

6. Start the User Service

Navigate to the user-service directory and run:

cd user-service
mvn spring-boot:run

User Service will be available at http://localhost:8081.

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Configuration

Eureka Server

application.yml for Eureka Server:

server:
  port: 8761

eureka:
  server:
    eviction-interval-timer-in-ms: 5000
  client:
    register-with-eureka: false
    fetch-registry: false

Spring Boot Admin

application.yml for Spring Boot Admin:

server:
  port: 9090

spring:
  application:
    name: spring-admin

  boot:
    admin:
      discovery:
        enabled: true

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
    register-with-eureka: true
    fetch-registry: true

API Gateway

application.yml for API Gateway:

server:
  port: 8080

spring:
  application:
    name: api-gateway

  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
          lower-case-service-id: true
      routes:
        - id: user-service
          uri: lb://user-service
          predicates:
            - Path=/users/**

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
    register-with-eureka: true
    fetch-registry: true

User Service

application.yml for User Service:

server:
  port: 8081

spring:
  application:
    name: user-service

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
    register-with-eureka: true
    fetch-registry: true

  instance:
    prefer-ip-address: true

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How to Access the Services

• Eureka Dashboard: http://localhost:8761
• Spring Boot Admin: http://localhost:9090
• API Gateway: http://localhost:8080
• User Service: http://localhost:8081

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Common Issues

1. Offline Instances in Spring Boot Admin

• Ensure all services are correctly registered in Eureka.
• Verify management.endpoints.web.exposure.include includes health and info.
• Restart services if stale instances are present in the registry.

2. Failed to Resolve Hostname

• Add prefer-ip-address: true in the application.yml of services.
• Replace any hardcoded hostnames with localhost.

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License

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