Netflix Feign-通过微服务传播状态和例外

问题描述

我正在使用 Netflix Feign 调用微服务A的一项操作，再调用微服务B的另一项其他操作，以使用Spring Boot验证代码.

I'm using Netflix Feign to call to one operation of a Microservice A to other other operation of a Microservice B which validates a code using Spring Boot.

如果验证不正确，微服务B的操作将引发异常.然后，我在微服务中处理并返回一个HttpStatus.UNPROCESSABLE_ENTITY(422)，如下所示:

The operation of Microservice B throws an exception in case of the validation has been bad. Then I handled in the Microservices and return a HttpStatus.UNPROCESSABLE_ENTITY (422) like next:

@ExceptionHandler({
       ValidateException.class
    })
    @ResponseStatus(HttpStatus.UNPROCESSABLE_ENTITY)
    @ResponseBody
    public Object validationException(final HttpServletRequest request, final validateException exception) {
        log.error(exception.getMessage(), exception);
        error.setErrorMessage(exception.getMessage());
        error.setErrorCode(exception.getCode().toString());
        return error;
    }

因此，当微服务A接下来在接口中调用B时:

So, when Microservice A calls to B in a interface as next:

@Headers("Content-Type: " + MediaType.APPLICATION_JSON_UTF8_VALUE)
@RequestLine("GET /other")
void otherOperation(@Param("other")  String other );

@Headers("Content-Type: " + MediaType.APPLICATION_JSON_UTF8_VALUE)
@RequestLine("GET /code/validate")
Boolean validate(@Param("prefix") String prefix);

static PromotionClient connect() {

    return Feign.builder()
        .encoder(new GsonEncoder())
        .decoder(new GsonDecoder())
        .target(PromotionClient.class, Urls.SERVICE_URL.toString());
}

并且验证失败它返回内部错误500和下一条消息:

and the validations fails It returns a internal error 500 with next message:

{
  "timestamp": "2016-08-05T09:17:49.939+0000",
  "status": 500,
  "error": "Internal Server Error",
  "exception": "feign.FeignException",
  "message": "status 422 reading Client#validate(String); content:\n{\r\n  \"errorCode\" : \"VALIDATION_EXISTS\",\r\n  \"errorMessage\" : \"Code already exists.\"\r\n}",
  "path": "/code/validate"
}

但是我需要返回与微服务操作B相同的结果.

But I need to return the same as the Microservice operation B.

使用Netflix Feign通过微服务传播状态和异常的最佳方法是什么?

Wich would be the best ways or techniques to propagate Status and Exceptions through microservices using Netflix Feign?

推荐答案

您可以使用伪装的ErrorDecoder

https://github.com/OpenFeign/feign/wiki/Custom-错误处理

这是一个例子

public class MyErrorDecoder implements ErrorDecoder {

    private final ErrorDecoder defaultErrorDecoder = new Default();

    @Override
    public Exception decode(String methodKey, Response response) {
        if (response.status() >= 400 && response.status() <= 499) {
            return new MyBadRequestException();
        }
        return defaultErrorDecoder.decode(methodKey, response);
    }

}

要让弹簧拾取ErrorDecoder，您必须将其放在ApplicationContext上:

For spring to pick up the ErrorDecoder you have to put it on the ApplicationContext:

@Bean
public MyErrorDecoder myErrorDecoder() {
  return new MyErrorDecoder();
}

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