Master Spring Cloud OpenFeign: Configuring URLs, Timeouts, Logging & Hystrix

Environment: Spring Boot 2.3.8.RELEASE + Spring Cloud Hoxton.SR8

Add the required Maven dependencies:

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
</dependencies>
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Configure the target service directly via URL

@FeignClient(value = "mv", url = "${feign.url}")
public interface PersonWeb {
    @GetMapping("/person/{id}")
    String get(@PathVariable Integer id);
}

feign:
  url: http://localhost:8001

Target service implementation:

@RestController
public class PersonController {
    @GetMapping("/person/{id}")
    Object get(@PathVariable Integer id) {
        return "Person";
    }
}

Note: The target service returns an Object (actually a String), so the Feign interface must declare String as the return type.

Modify default configuration attributes of

@FeignClient

@FeignClient(value = "mv", url = "${feign.url}", configuration = FeignConfig.class)
public interface PersonWeb { ... }

public class FeignConfig {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
}

The above JavaConfig sets the default logger level; the same can be done via properties.

Logging level configuration (application.yml):

logging:
  level:
    com.pack.controller.PersonWeb: debug

Set request timeout

feign:
  url: http://localhost:8001
  httpclient:
    enabled: true
  client:
    config:
      mv:
        connectTimeout: 2000
        readTimeout: 2000

The mv key corresponds to the value (or name) defined in @FeignClient.

Adjust the target service to delay response by 5 seconds:

@GetMapping("/person/{id}")
public Object get(@PathVariable Integer id) {
    try {
        TimeUnit.SECONDS.sleep(5);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    return "Person";
}

The console shows timeout errors, confirming that the readTimeout setting is effective.

Log level configuration

feign:
  logger-level: basic

This setting overrides the logger level defined in FeignConfig.

Circuit‑breaker support

Supported circuit‑breaker implementations include Netfix Hystrix, Resilience4J, Sentinel, and Spring Retry. This example uses Hystrix.

feign:
  hystrix:
    enabled: true

@Component
public class PersonFallback implements PersonWeb {
    @Override
    public String get(Integer id) {
        return "我是返回的默认值";
    }
}

@FeignClient(value = "mv", url = "${feign.url}", configuration = FeignConfig.class, fallback = PersonFallback.class)
public interface PersonWeb { ... }

Hystrix’s default timeout is 1 second, while the target service sleeps for 5 seconds.

Modify Hystrix timeout via configuration:

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

hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 3000
      timeout:
        enabled: true

Obtain exception details with a FallbackFactory:

@Component
public class PersonFallbackFactory implements FallbackFactory<PersonWeb> {
    @Override
    public PersonWeb create(Throwable cause) {
        cause.printStackTrace();
        return new PersonWeb() {
            @Override
            public String get(Integer id) {
                return "fallback";
            }
        };
    }
}

@FeignClient(value = "mv", url = "${feign.url}", configuration = FeignConfig.class, fallbackFactory = PersonFallbackFactory.class)
public interface PersonWeb { ... }

Feign inheritance support

public interface BaseController {
    @GetMapping("/person/{id}")
    String get(@PathVariable Integer id);
}

@RestController
@RequestMapping("/demo")
public class DemoController implements BaseController {
    @Resource
    private PersonWeb personWeb;

    @GetMapping("/person/{id}")
    public String get(@PathVariable Integer id) {
        return personWeb.get(id);
    }
}

@FeignClient(value = "mv", url = "${feign.url}", configuration = FeignConfig.class, fallbackFactory = PersonFallbackFactory.class)
public interface PersonWeb extends BaseController { }

Using inheritance in this way is generally not recommended.

Final application entry point:

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

Done!!