Styjun

I tried Feign to configure Hystrix. Enter 127.0.0.1:8100/test in the browser address bar. No matter whether it is configured with fallback or fallbackFactory, the result of the prompt is: "com.netflix.client.ClientException: Load balancer does not have available server for client: microservice-provider-user", this Explain that fallback is not working.

Controller

@Import(FeignClientsConfiguration.class)
@RestController
public class TestController 

 private UserFeignClient userFeignClient;

 private UserFeignClient adminFeignClient;

 @Autowired
 public TestController(Decoder decoder, Encoder encoder, Client client, Contract contract) 
 this.userFeignClient = Feign.builder().client(client).encoder(encoder)
 .decoder(decoder).contract(contract)
 .requestInterceptor(new BasicAuthRequestInterceptor("user", "user"))
 .target(UserFeignClient.class, "http://microservice-provider-user/");

 this.adminFeignClient = Feign.builder().client(client).encoder(encoder)
 .decoder(decoder).contract(contract)
 .requestInterceptor(new BasicAuthRequestInterceptor("admin", "admin"))
 .target(UserFeignClient.class, "http://microservice-provider-user/");
 

 @GetMapping("/test")
 @ResponseBody
 public String test() 
 return userFeignClient.findById(123L);
 

 @GetMapping("/testAdmin")
 @ResponseBody
 public String test2() 
 return adminFeignClient.findById(123L);
 

Main method

@SpringBootApplication
@EnableFeignClients
@EnableHystrixDashboard
@EnableHystrix
@EnableCircuitBreaker
public class Demo2Application 

 public static void main(String[] args) 
 SpringApplication.run(Demo2Application.class, args);
 

fallback

@Component
public class FeignClientFallback implements UserFeignClient
 @Override
 public String findById(Long id) 
 return "hello FeignClientFallback";
 

gradle

plugins 
 id 'org.springframework.boot' version '2.1.3.RELEASE'
 id 'java'


apply plugin: 'io.spring.dependency-management'

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories 
 mavenCentral()


ext 
 set('springCloudServicesVersion', '2.1.2.RELEASE')
 set('springCloudVersion', 'Greenwich.SR1')


dependencies 
 implementation 'org.springframework.boot:spring-boot-starter-actuator'
 implementation 'org.springframework.boot:spring-boot-starter-web'
 implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
 implementation 'org.springframework.cloud:spring-cloud-starter-netflix-hystrix'
 implementation 'org.springframework.cloud:spring-cloud-starter-netflix-hystrix-dashboard'
 implementation 'org.springframework.cloud:spring-cloud-starter-netflix-turbine'
 implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
 testImplementation 'org.springframework.boot:spring-boot-starter-test'


dependencyManagement 
 imports 
 mavenBom "io.pivotal.spring.cloud:spring-cloud-services-dependencies:$springCloudServicesVersion"
 mavenBom "org.springframework.cloud:spring-cloud-dependencies:$springCloudVersion"
 

Feign client

@FeignClient(name = "microservice-provider-user", fallback = FeignClientFallback.class)
public interface UserFeignClient 

 @GetMapping("/test2/id")
 String findById(@PathVariable("id") Long id);

application.yml

spring:
 application:
 name: microservice-custom
eureka:
 client:
 serviceUrl:
 defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
 healthcheck:
 enabled: true
 instance:
 prefer-ip-address: true

server:
 port: 8100

feign:
 hystrix:
 enabled: true
 client:
 config:
 default:
 connectTimeout: 1000
 readTimeout: 1000
 loggerLevel: basic

hystrix:
 command:
 default:
 execution:
 isolation:
 strategy: SEMAPHORE

logging:
 level:
 com.lv.springCloudClient1.UserFeignClient: DEBUG

management:
 endpoints:
 web:
 exposure:
 include: '*'

In theory, if I turn off the "microservice-provider-user" server, I will get the content returned by the fallback method.

@Import(FeignClientsConfiguration.class)
@RestController
public class TestController 

 @Autowired
 private UserFeignClient userFeignClient;

 @Autowired
 private UserFeignClient adminFeignClient;

 @GetMapping("/test")
 @ResponseBody
 public String test() 
 return userFeignClient.findById(123L);
 

 @GetMapping("/testAdmin")
 @ResponseBody
 public String test2() 
 return adminFeignClient.findById(123L);
 

I changed the previous controller code to the current one.
the Hystrix fallback method is effective.