自定义 Zuul 异常

Question

我在 Zuul 中有一个场景，URL 路由的服务也可能已关闭。因此，响应主体在 JSON 主体响应中抛出 500 HTTP 状态和 ZuulException。

{
  "timestamp": 1459973637928,
  "status": 500,
  "error": "Internal Server Error",
  "exception": "com.netflix.zuul.exception.ZuulException",
  "message": "Forwarding error"
}

我只想自定义或删除 JSON 响应，并可能更改 HTTP 状态代码。

我尝试使用@ControllerAdvice 创建一个异常处理程序，但该异常未被处理程序捕获。

更新：

所以我扩展了 Zuul Filter 我可以看到它在执行错误后进入运行方法然后我该如何更改响应。以下是我到目前为止得到的。我在某处读到有关 SendErrorFilter 的信息，但我该如何实现它以及它有什么作用？

public class CustomFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return "post";
    }

    @Override
    public int filterOrder() {

        return 1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() {
        final RequestContext ctx = RequestContext.getCurrentContext();
        final HttpServletResponse response = ctx.getResponse();
        if (HttpStatus.INTERNAL_SERVER_ERROR.value() == ctx.getResponse().getStatus()) {
            try {
                response.sendError(404, "Error Error"); //trying to change the response will need to throw a JSON body.
            } catch (final IOException e) {
                e.printStackTrace();
            } ;
        }

        return null;
    }

将此添加到具有 @EnableZuulProxy

的 class

@Bean
public CustomFilter customFilter() {
    return new CustomFilter();
}

Answer 1

转发通常由过滤器完成，在这种情况下，请求甚至不会到达控制器。这可以解释为什么你的 @ControllerAdvice 不起作用。

如果您在控制器中转发，@ControllerAdvice 应该可以工作。检查 spring 是否创建了带有 @ControllerAdvice 注释的 class 实例。为此，在 class 中放置一个断点并查看它是否被命中。

也在转发应该发生的控制器方法中添加一个断点。可能是您不小心调用了另一个控制器方法而不是检查？

这些步骤应该可以帮助您解决问题。

在用@ControllerAdvice 注释的class 中添加一个用@ExceptionHandler(Exception.class) 注释的ExceptionHandler 方法，它应该捕获每个异常。

编辑： 您可以尝试添加自己的过滤器来转换 Zuulfilter 返回的错误响应。在那里您可以根据需要更改响应。

这里解释了如何自定义错误响应：

exception handling for filter in spring

正确放置过滤器可能有点棘手。不确定正确的位置，但您应该了解过滤器的顺序和处理异常的位置。

如果将它放在 Zuulfilter 之前，则必须在调用 doFilter() 之后编写错误处理代码。

如果将它放在 Zuulfilter 之后，则必须在调用 doFilter() 之前编写错误处理代码。

在 doFilter() 之前和之后的过滤器中添加断点可能有助于找到正确的位置。

Answer 2

我们终于成功了 [由我的一位同事编码]:-

public class CustomErrorFilter extends ZuulFilter {

    private static final Logger LOG = LoggerFactory.getLogger(CustomErrorFilter.class);
    @Override
    public String filterType() {
        return "post";
    }

    @Override
    public int filterOrder() {
        return -1; // Needs to run before SendErrorFilter which has filterOrder == 0
    }

    @Override
    public boolean shouldFilter() {
        // only forward to errorPath if it hasn't been forwarded to already
        return RequestContext.getCurrentContext().containsKey("error.status_code");
    }

    @Override
    public Object run() {
        try {
            RequestContext ctx = RequestContext.getCurrentContext();
            Object e = ctx.get("error.exception");

            if (e != null && e instanceof ZuulException) {
                ZuulException zuulException = (ZuulException)e;
                LOG.error("Zuul failure detected: " + zuulException.getMessage(), zuulException);

                // Remove error code to prevent further error handling in follow up filters
                ctx.remove("error.status_code");

                // Populate context with new response values
                ctx.setResponseBody(“Overriding Zuul Exception Body”);
                ctx.getResponse().setContentType("application/json");
                ctx.setResponseStatusCode(500); //Can set any error code as excepted
            }
        }
        catch (Exception ex) {
            LOG.error("Exception filtering in custom error filter", ex);
            ReflectionUtils.rethrowRuntimeException(ex);
        }
        return null;
    }
}

Answer 3

我遇到了同样的问题，并且能够以更简单的方式解决它

只要把这个放到你的过滤器run()方法中

    if (<your condition>) {
        ZuulException zuulException = new ZuulException("User message", statusCode, "Error Details message");
        throw new ZuulRuntimeException(zuulException);
    }

和 SendErrorFilter 将向用户发送包含所需 statusCode 的消息。

Exception 模式中的这个 Exception 看起来不太好，但它在这里有效。

Answer 4

以下是使用@ControllerAdvice 执行此操作的步骤：

首先添加一个error类型的过滤器，让它在zuul本身的SendErrorFilter之前运行。
确保从 RequestContext 中删除与异常关联的键以防止 SendErrorFilter 执行。
使用 RequestDispatcher 将请求转发给 ErrorController -- 解释如下。
添加一个@RestController class 并使其扩展 AbstractErrorController，并再次重新抛出异常（在使用 (key, exception) 执行新错误过滤器的步骤中添加它），从控制器中的 RequestContext 获取它。

异常现在将在您的@ControllerAdvice 中捕获class。

Answer 5

Zuul RequestContext 不包含中提到的 error.exception。
更新 Zuul 错误过滤器：

@Component
public class ErrorFilter extends ZuulFilter {
    private static final Logger LOG = LoggerFactory.getLogger(ErrorFilter.class);

    private static final String FILTER_TYPE = "error";
    private static final String THROWABLE_KEY = "throwable";
    private static final int FILTER_ORDER = -1;

    @Override
    public String filterType() {
        return FILTER_TYPE;
    }

    @Override
    public int filterOrder() {
        return FILTER_ORDER;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() {
        final RequestContext context = RequestContext.getCurrentContext();
        final Object throwable = context.get(THROWABLE_KEY);

        if (throwable instanceof ZuulException) {
            final ZuulException zuulException = (ZuulException) throwable;
            LOG.error("Zuul failure detected: " + zuulException.getMessage());

            // remove error code to prevent further error handling in follow up filters
            context.remove(THROWABLE_KEY);

            // populate context with new response values
            context.setResponseBody("Overriding Zuul Exception Body");
            context.getResponse().setContentType("application/json");
            // can set any error code as excepted
            context.setResponseStatusCode(503);
        }
        return null;
    }
}

Answer 6

    The simplest solution is to follow first 4 steps.


     1. Create your own CustomErrorController extends
        AbstractErrorController which will not allow the
        BasicErrorController to be called.
     2. Customize according to your need refer below method from
        BasicErrorController.

    <pre><code> 
        @RequestMapping
        public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
            Map<String, Object> body = getErrorAttributes(request,
                    isIncludeStackTrace(request, MediaType.ALL));
            HttpStatus status = getStatus(request);
            return new ResponseEntity<>(body, status);
        }
    </pre></code> 

     4. You can control whether you want exception / stack trace to be printed or not can do as mentioned below:
    <pre><code>
    server.error.includeException=false
    server.error.includeStacktrace=ON_TRACE_PARAM
    </pre></code>
 ====================================================

    5. If you want all together different error response re-throw your custom exception from your CustomErrorController and implement the Advice class as mentioned below:

    <pre><code>

@Controller
@Slf4j
public class CustomErrorController extends BasicErrorController {

    public CustomErrorController(ErrorAttributes errorAttributes, ServerProperties serverProperties,
            List<ErrorViewResolver> errorViewResolvers) {

        super(errorAttributes, serverProperties.getError(), errorViewResolvers);
        log.info("Created");
    }

    @Override
    public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
        Map<String, Object> body = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.ALL));
        HttpStatus status = getStatus(request);
        throw new CustomErrorException(String.valueOf(status.value()), status.getReasonPhrase(), body);
    }
}


    @ControllerAdvice
    public class GenericExceptionHandler {
    // Exception handler annotation invokes a method when a specific exception
        // occurs. Here we have invoked Exception.class since we
        // don't have a specific exception scenario.
        @ExceptionHandler(CustomException.class)
        @ResponseBody
        public ErrorListWsDTO customExceptionHandle(
                final HttpServletRequest request,
                final HttpServletResponse response,
                final CustomException exception) {
                LOG.info("Exception Handler invoked");
                ErrorListWsDTO errorData = null;
                errorData = prepareResponse(response, exception);
                response.setStatus(Integer.parseInt(exception.getCode()));
                return errorData;
        }

        /**
         * Prepare error response for BAD Request
         *
         * @param response
         * @param exception
         * @return
         */
        private ErrorListWsDTO prepareResponse(final HttpServletResponse response,
                final AbstractException exception) {
                final ErrorListWsDTO errorListData = new ErrorListWsDTO();
                final List<ErrorWsDTO> errorList = new ArrayList<>();
                response.setStatus(HttpStatus.BAD_REQUEST.value());
                final ErrorWsDTO errorData = prepareErrorData("500",
                        "FAILURE", exception.getCause().getMessage());
                errorList.add(errorData);
                errorListData.setErrors(errorList);
                return errorListData;
        }

        /**
         * This method is used to prepare error data
         *
         * @param code
         *            error code
         * @param status
         *            status can be success or failure
         * @param exceptionMsg
         *            message description
         * @return ErrorDTO
         */
        private ErrorWsDTO prepareErrorData(final String code, final String status,
                final String exceptionMsg) {

                final ErrorWsDTO errorDTO = new ErrorWsDTO();
                errorDTO.setReason(code);
                errorDTO.setType(status);
                errorDTO.setMessage(exceptionMsg);
                return errorDTO;
        }

    }
    </pre></code>

Answer 7

这对我有用。 RestExceptionResponse 是在@ControllerAdvice 中使用的 class，因此在内部 ZuulExceptions 的情况下我们有相同的异常响应。

@Component
@Log4j
public class CustomZuulErrorFilter extends ZuulFilter {

    private static final String SEND_ERROR_FILTER_RAN = "sendErrorFilter.ran";

    @Override
    public String filterType() {
        return ERROR_TYPE;
    }

    @Override
    public int filterOrder() {
        return SEND_ERROR_FILTER_ORDER - 1; // Needs to run before SendErrorFilter which has filterOrder == 0
    }

    @Override
    public boolean shouldFilter() {
        RequestContext ctx = RequestContext.getCurrentContext();
        Throwable ex = ctx.getThrowable();
        return ex instanceof ZuulException && !ctx.getBoolean(SEND_ERROR_FILTER_RAN, false);
    }

    @Override
    public Object run() {
        try {
            RequestContext ctx = RequestContext.getCurrentContext();
            ZuulException ex = (ZuulException) ctx.getThrowable();

            // log this as error
            log.error(StackTracer.toString(ex));

            String requestUri = ctx.containsKey(REQUEST_URI_KEY) ? ctx.get(REQUEST_URI_KEY).toString() : "/";
            RestExceptionResponse exceptionResponse = new RestExceptionResponse(HttpStatus.INTERNAL_SERVER_ERROR, ex, requestUri);

            // Populate context with new response values
            ctx.setResponseStatusCode(500);
            this.writeResponseBody(ctx.getResponse(), exceptionResponse);

            ctx.set(SEND_ERROR_FILTER_RAN, true);
        }
        catch (Exception ex) {
            log.error(StackTracer.toString(ex));
            ReflectionUtils.rethrowRuntimeException(ex);
        }
        return null;
    }


    private void writeResponseBody(HttpServletResponse response, Object body) throws IOException {
        response.setContentType("application/json");
        try (PrintWriter writer = response.getWriter()) {
            writer.println(new JSonSerializer().toJson(body));
        }
    }
}

输出如下所示：

{
    "timestamp": "2020-08-10 16:18:16.820",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/service",
    "exception": {
        "message": "Filter threw Exception",
        "exceptionClass": "com.netflix.zuul.exception.ZuulException",
        "superClasses": [
            "com.netflix.zuul.exception.ZuulException",
            "java.lang.Exception",
            "java.lang.Throwable",
            "java.lang.Object"
        ],
        "stackTrace": null,
        "cause": {
            "message": "com.netflix.zuul.exception.ZuulException: Forwarding error",
            "exceptionClass": "org.springframework.cloud.netflix.zuul.util.ZuulRuntimeException",
            "superClasses": [
                "org.springframework.cloud.netflix.zuul.util.ZuulRuntimeException",
                "java.lang.RuntimeException",
                "java.lang.Exception",
                "java.lang.Throwable",
                "java.lang.Object"
            ],
            "stackTrace": null,
            "cause": {
                "message": "Forwarding error",
                "exceptionClass": "com.netflix.zuul.exception.ZuulException",
                "superClasses": [
                    "com.netflix.zuul.exception.ZuulException",
                    "java.lang.Exception",
                    "java.lang.Throwable",
                    "java.lang.Object"
                ],
                "stackTrace": null,
                "cause": {
                    "message": "Load balancer does not have available server for client: template-scalable-service",
                    "exceptionClass": "com.netflix.client.ClientException",
                    "superClasses": [
                        "com.netflix.client.ClientException",
                        "java.lang.Exception",
                        "java.lang.Throwable",
                        "java.lang.Object"
                    ],
                    "stackTrace": null,
                    "cause": null
                }
            }
        }
    }
}

自定义 Zuul 异常

Customizing Zuul Exception

java

spring-boot

microservices

spring-cloud

netflix-zuul