feign-plus

A better feign client library to combine with SpringBoot.

---

Write Feign client with annotation, like this:

We can provider an interface.

@RequestMapping("/v1/demo")
@FeignPlusClient(name = "demo", url = "${feign.demo.url}", port = "${feign.demo.port}")
public interface DemoApi {
    @GetMapping("/id")
    String sayHello(@RequestParam(value = "id") Long id);

    @GetMapping("/id/{id}")
    String id(@PathVariable(value = "id") Long id);

    @PostMapping("/create")
    Order create(@RequestBody OrderCreateReq req);

    @GetMapping("/query")
    Order query(@SpringQueryMap OrderQueryDTO dto);
}

Now we can use it as we normally use SpringBoot.

@SpringBootApplication
@EnableFeignPlusClients(basePackages = "com.example.provider.api")
@RestController
public class DemoApplication {

	@Resource
	private DemoApi demoApi;

	@GetMapping(value = "/hello")
	public String hello() {
		demoApi.id(12L);
		demoApi.sayHello(34L);
		demoApi.create(new OrderCreateReq("100"));
		demoApi.query(new OrderQueryDTO("999", "zhangsan"));
		return "hello";
	}

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

}

Feature

• Request/Response/Exception log record.
• Custom interceptor.
• Micrometer support.
• Exception passing.

Interceptor

By default, the request log is logged using the debug level.

For custom interceptor you need to create a bean that extends the DefaultLogInterceptor.

Example usage:

@Component
@Slf4j
public class CustomFeignInterceptor extends DefaultLogInterceptor {
    @Override
    public void request(String target, String url, String body) {
        super.request(target, url, body);
        log.info("request");
    }

    @Override
    public void exception(String target, String url, FeignException feignException) {
        super.exception(target, url, feignException);
    }

    @Override
    public void response(String target, String url, Object response) {
        super.response(target, url, response);
        log.info("response");
    }
}

Exception passing

Custom exception like this:

@Data
public class DemoException extends RuntimeException {
    private String appName;
    private int code;
    private String debugStackTrace;
}    

Provier

When the provider throws an exception:

    @GetMapping("/query")
	public Order query(OrderQueryDTO dto) {
		log.info("dto = {}", dto);
		if (dto.getId().equals("1")) {
			throw new DemoException("provider test exception");
		}
		return new Order(dto.getId());
	}

consumer will get a return of HTTP_CODE = 500.

{
"appName": "provider-demo",
"code": 500,
"message": "provider test exception",
"debugStackTrace": "com.example.provider.api.exception.DemoException: provider test exception\n\tat com.exampl.provider.core.ProviderApplication.query(ProviderApplication.java:49)\n\tat"
}

Consumer

Configuring an exception decoder:

@Configuration
public class FeignExceptionConfig {
    @Bean
    public FeignErrorDecoder feignExceptionDecoder() {
        return (methodName, response, e) -> {
            HttpStatus status = JSONUtil.toBean(response, HttpStatus.class);
            return new DemoException(status.getAppName(), status.getCode(), status.getMessage(), status.getDebugStackTrace());
        };
    }
}

then the consumer can catch DemoException like local call:

    try {
        demoApi.query(new OrderQueryDTO(id, "zhangsan"));
    } catch (DemoException e) {
        log.error("feignCall:{}, sourceApp:[{}], sourceStackTrace:{}", e.getMessage(), e.getAppName(), e.getDebugStackTrace(), e);
    }

More configuration

feign:
  plus:
    connect-timeout: 11000
    max-idle-connections: 520
    read-timeout: 12000