netflix-ribbon.md

Read more about Netflix Ribbon

Ribbon is a client load balancing with variety of load balancing strategies, can be used with service discovery and circuit breakers. Lists all the machines in the configuration, and Ribbon will automatically connect those machines based on certain rules (simple polling, random connections, etc.)

Ribbon can do 1) load balancing; 2) fault-tolerance; 3) support multi-protocol (HTT, TCP, UDP) in asynchronous and reactive models; 4) cache and batch

Build Ribbon service

• Build mvn and name it ribbon, core dependencies:

   <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-ribbon</artifactId>
  </dependency>     
  

• In the application class of application entry

  @SpringBootApplication
  @EnableDiscoveryClient
  public class RibbonApplication {
       
      @Bean
      @LoadBalanced
      RestTemplate restTemplate() {
          return new RestTemplate();
      }
   
      public static void main(String[] args) {
          SpringApplication.run(RibbonApplication.class, args);
      }
  }     
  

  @LoadBalanced: declare a loadBalanced template

• Create a remote call service

  @RestController
  public class DemoController {
   
      @Autowired
      RestTemplate restTemplate;
   
      @RequestMapping(value = "/ribbon", method = RequestMethod.GET)
      public String add() {
          return restTemplate.getForEntity("http://EUREKA-SERVICE/demo/show", String.class).getBody();
      }
  }
  

  EUREKA-SERVICE is the service registered in eureka module

  remote call /demo/show REST interface, can be replace with ／demo/index etc.

• Configuration

  spring.application.name=ribbon
  server.port=5000
  eureka.client.serviceUrl.defaultZone=http://${EUREKA_HOST}:${EUREKA_PORT}/eureka/
  eureka.instance.preferIpAddress=true     
  

  EUREKA_HOST: registry ip

  EUREKA_PORT: registry interface

• Address

  http://DOCKER_HOST:DOCKER_PORT/ribbon