"Feign (ribbon + hystrix + hystrix monitoring) tool integration"

background

Look at the feignindividual article Feign declarative client interface

Many tools in spring cloud are used together. Feign integrates ribbon and hystrix and provides a declarative consumer client. We use these tools together

• ribbon-load balancing, retry

• hystrix-circuit breaker (degraded, blown)

用 feign 代替 hystrix+ribbon

---

feign + ribbon load balancing and retry

1-load balancing

No additional configuration is required, feign has enabled the ribbon 负载均衡and 重试mechanism, and the parameters can be called through configuration

ConnectTimeout=1000
ReadTimeout=1000
MaxAutoRetries=0
MaxAutoRetriesNextServer=1

2-Configure ribbon timeout and retry

• ribbon-global configuration
• item-service-configuration of a specific service instance

spring:
  application:
    name: feign
    
server:
  port: 3001
  
eureka:
  client:
    service-url:
      defaultZone: http://eureka1:2001/eureka, http://eureka2:2002/eureka
      
ribbon:
  ConnectTimeout: 1000
  ReadTimeout: 1000
  
item-service:
  ribbon:
    MaxAutoRetries: 1
    MaxAutoRetriesNextServer: 2
    ConnectTimeout: 1000
    ReadTimeout: 500

Start the service, access the test

http://localhost:3001/item-service/35

prompt:

重载 一般不怎么使用，看项目的需求，如果需要才用

负载均衡默认都是有的，看情况，如果项目需要才用上

---

---

feign + hystrix downgrade

1-feign enables hystrix

feign 默认没有启用 hystrix, add configuration, enable hystrix

1.1-application.yml add configuration

feign:
  hystrix:
    enabled: true

1.2 After enabling hystrix, access the service

http://localhost:3001/item-service/35

默认1秒会快速失败，没有降级方法时，会显示白板页

---

---

2-feign implements hystrix downgrade

Degrade class specified in the remote interface

aims:远程调用失败, 会执行降级类中的代码

2-1 Remote interface (interface)

ItemClient

@FeignClient(name="item-service",fallback = ItemClientFB.class)
public interface ItemClient {
    
    
...
...

OrderClient

...
@FeignClient(name="order-service",fallback = OrderClientFB.class)
public interface OrderClient{
    
    
...

UserClient

...
@FeignClient(name="user-service",fallback = UserClientFB.class)
public interface UserClient{
    
    
...

2-2 Downgrade class

The downgrade class needs to implement the remote interface

ItemClientFB

@Component
public class ItemClientFB implements ItemClient{
    
    
    @Override
    public JsonResult<List<Item>> getItems(String orderId) {
    
    
        return JsonResult.err().msg("调用商品失败");
    }

    @Override
    public JsonResult<?> decreaseNumber(List<Item> items) {
    
    
        return JsonResult.err().msg("调用商品失败");
    }
}

OrderClientFB

@Component
public class OrderClientFB implements OrderClient{
    
    
    @Override
    public JsonResult<Order> getOrder(String orderId) {
    
    
        return JsonResult.err().msg("调用订单失败");
    }

    @Override
    public JsonResult<?> saveOrder() {
    
    
        return JsonResult.err().msg("调用订单失败");
    }
}

UserClientFB

@Component
public class UserClientFB implements UserClient{
    
    
    @Override
    public JsonResult<User> getUser(Integer userId) {
    
    
        return JsonResult.err().msg("调用用户失败");
    }

    @Override
    public JsonResult<?> addScore(Integer userId, Integer score) {
    
    
        return JsonResult.err().msg("调用用户失败");
    }
}

---

---

2-3 Start service, access test

http://localhost:3001/item-service/35

Jump to the degraded object after the call fails （降级成功）

---

---

feign + hystrix monitoring

1-pom.xml add hystrix start-up dependency

feign 没有包含完整的 hystrix 依赖

1-1 xml dependency

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

1-2 visual dependencies

---

Main program added @EnableCircuitBreaker

@EnableCircuitBreaker
@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class Sp09FeignApplication {
    
    
    public static void main(String[] args) {
    
    
        SpringApplication.run(Sp09FeignApplication.class, args);
    }

}

---

2-Configure actuator to expose hystrix.stream monitoring endpoint

View pom.xml, confirmation has been added actuatordependent

2-1 actuator dependent

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

2-2 application.yml exposes hystrix.stream endpoint

management:
  endpoints:
    web:
      exposure:
        include: hystrix.stream

---

3-Start the service and view the monitoring endpoint

http://localhost:3001/actuator

---

4-hystrix dashboard (monitoring instrument)

If you don’t have a hystrix dashboard or have never learned it, then please enter the hystrix dashboard circuit breaker dashboard

Start the hystrix dashboard service, fill in the feign monitoring path, and start monitoring

• Access the instrument server: http://localhost:4001/hystrix

• Fill in the feign monitoring path: http://localhost:3001/actuator/hystrix.stream

• Access to microservices to generate monitoring data

Access business server: http://localhost:3001/item-service/35