Hackforge Academy

Explanation

An API Gateway acts as the single entry point for all client requests. Instead of calling individual microservices directly, clients send requests to the gateway, which routes them to the appropriate service.

Code:

Client
   |
Spring Cloud Gateway
   |
-------------------------
Student Service
Course Service
Payment Service

Explanation

Spring Cloud Gateway provides routing, authentication, rate limiting, logging, and request filtering for microservices.

Code:

spring:
  cloud:
    gateway:
      routes:
        - id: student-service
          uri: lb://student-service
          predicates:
            - Path=/students/**

Explanation

Eureka Server is a Service Discovery server where all microservices register themselves. It maintains a registry of available services.

Code:

@EnableEurekaServer
@SpringBootApplication
public class EurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaServerApplication.class, args);
    }
}

Explanation

Each microservice registers with Eureka using its application name. Other services and the API Gateway can discover it dynamically without hardcoding server addresses.

Code:

spring.application.name=student-service

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

Explanation

The API Gateway uses load-balanced URLs (lb://service-name) to forward requests to available service instances. This enables load balancing and high availability in microservice architectures.

Code:

spring:
  cloud:
    gateway:
      routes:
        - id: course-service
          uri: lb://course-service
          predicates:
            - Path=/courses/**