Customizing Zuul Exception

Question

I have a scenario in Zuul where the service that the URL is routed too might be down . So the reponse body gets thrown with 500 HTTP Status and ZuulException in the JSON bod

Answer 1

Forwarding is often done by a filter, in this case the request does not even reach a controller. This would explain why your @ControllerAdvice does not work.

If you forward in the controller than the @ControllerAdvice should work. Check if spring creates an instance of the class annotated with @ControllerAdvice. For that place a breakpoint in the class and see whether it is hit.

Add a breakpoint also in the controller method where the forwarding should happen. May be you accidently invoke another controller method than you inspect ?

These steps should help you resolve the issue.

In your class annotated with @ControllerAdvice add an ExceptionHandler method annotated with @ExceptionHandler(Exception.class), that should catch every Exception.

EDIT : You can try to add your own filter that converts the error response returned by the Zuulfilter. There you can change the response as you like.

How the error response can be customized is explained here :

exception handling for filter in spring

Placing the filter correctly may be a little tricky. Not exactly sure about the correct position, but you should be aware of the order of your filters and the place where you handle the exception.

If you place it before the Zuulfilter, you have to code your error handling after calling doFilter().

If you place it after the Zuulfilter, you have to code your error handling before calling doFilter().

Add breakpoints in your filter before and after doFilter() may help to find the correct position.