A hub to let each services to find each other

1. Create another Spring Project: service-registry

2. Dependencies: spring-cloud-starter-netflix-eureka-server

3. Main class enable eureka service

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

4. Setup application.yml

   server:
     port: 8761
   
   eureka:
     client:
       register-with-eureka: false
       fetch-registry: false
   

5. Register EACH services with Eureka, for each services:

   1. Add dependency : spring-cloud-starter-netflix-eureka-client
   2. Add eureka in application.yml

   spring:
     application:
       name: user-service
     
     # to let the service know Config Server 
     cloud:
       config:
         uri: <http://localhost:8888>
   
   eureka:
     client:
       service-url:
         defaultZone: <http://localhost:8761/eureka>
   

6. Now when the service start, will registers itself with Eureka. (can check in eureka port)

7. Create service config in service that want to call other services

   @Bean
   @LoadBalanced
   public WebClient.Builder webClientBuilder() {
       return WebClient.builder();
   }
   

8. When other service need another service, call the service name

   • http://user-service/users/123
   • Spring Cloud will ask Eureka, then gets available instances, and auto load-balances

   @Service
   public class OrderService {
   
       private final WebClient webClient;
   
       public Mono<UserDto> getUser(String userId) {
           return webClient
                   .get()
                   **.uri("<http://user-service/users/{id}>", userId)**
                   .retrieve()
                   .bodyToMono(UserDto.class);
       }
   }