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:

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

Configure the target service directly via URL

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

<code>feign:
  url: http://localhost:8001</code>

Target service implementation:

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

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

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

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

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

Logging level configuration (application.yml):

<code>logging:
  level:
    com.pack.controller.PersonWeb: debug</code>

Set request timeout

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

The

mv

key corresponds to the

value

(or

name

) defined in

@FeignClient

.

Adjust the target service to delay response by 5 seconds:

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

The console shows timeout errors, confirming that the

readTimeout

setting is effective.

Log level configuration

<code>feign:
  logger-level: basic</code>

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.

<code>feign:
  hystrix:
    enabled: true</code>

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

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

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

Modify Hystrix timeout via configuration:

<code>&lt;dependency&gt;
    &lt;groupId&gt;org.springframework.cloud&lt;/groupId&gt;
    &lt;artifactId&gt;spring-cloud-starter-netflix-hystrix&lt;/artifactId&gt;
&lt;/dependency&gt;</code>

<code>hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 3000
      timeout:
        enabled: true</code>

Obtain exception details with a

FallbackFactory

:

<code>@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 { ... }</code>

Feign inheritance support

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

<code>@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);
    }
}</code>

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

Using inheritance in this way is generally not recommended.

Final application entry point:

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

Done!!