How to customize Spring boot controller API response for ZuulException

Question

We are using Zuul, Eureka and spring boot application services for REST APIs.

Suppose my spring boot service is down and when I tried to access the API using Zuul API gateway, I am getting ZuulException and response is below :

{
    "timestamp": "2018-10-12T14:29:09.632+0000",
    "status": 500,
    "error": "Internal Server Error",
    "exception": "com.netflix.zuul.exception.ZuulException",
    "message": "GENERAL"
}

I want to customize the response format like below:

{
    "success": false,
    "message": "Service is down. Please try later"
}

I tried to implement https://stackoverflow.com/a/39841785/5506061 but its not working for me.

Please suggest how to customize the response for ZuulException.

score 0 · Answer 1 · answered Nov 13 '18 at 10:57

You can implement your own FallbackProvider and customize the response based on the cause if needed.

Something like :

@Component
public class CustomFallbackBasedOnCause implements FallbackProvider {

private static final String DEFAULT_MSG = "{\"success\": false,\"message\": \"Service is down. Please try later\"}";

@Override
public String getRoute() {
    return "*"; // * = all routes
}

@Override
public ClientHttpResponse fallbackResponse(final Throwable cause) {
    if (cause instanceof HystrixTimeoutException) {
        return response(HttpStatus.GATEWAY_TIMEOUT);
    } else {
        return fallbackResponse();
    }
}

@Override
public ClientHttpResponse fallbackResponse() {
    return response(HttpStatus.INTERNAL_SERVER_ERROR);
}

private ClientHttpResponse response(final HttpStatus status) {
    return new ClientHttpResponse() {
        @Override
        public HttpStatus getStatusCode() throws IOException {
            return status;
        }

        @Override
        public int getRawStatusCode() throws IOException {
            return status.value();
        }

        @Override
        public String getStatusText() throws IOException {
            return status.getReasonPhrase();
        }

        @Override
        public void close() {
        }

        @Override
        public InputStream getBody() throws IOException {
            return new ByteArrayInputStream(DEFAULT_MSG.getBytes());
        }

        @Override
        public HttpHeaders getHeaders() {
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_JSON);
            return headers;
        }
    };
}
}

As you can see in the getRoute() method, you can specify if this customFallback will be used for all routes (return "*") or for a specific route.

In case you work with Registry service (e.g Eureka). You don’t specify the route URL but the service id instead. return "SERVICEID"

How to customize Spring boot controller API response for ZuulException

1 Answers1