title: Spring Cloud: How to define default fallback for Hystrix in Zuul gateway?
body: <p>I am using Spring Cloud Brixton.M3 and Spring Boot 1.3.0.RELEASE. I am sort of new in this (especially in Spring Cloud). I have created Registry Server (i.e. Eureka instance), Config server and Gateway.<br>
  As per my requirement I am intercepting each request hitting the gateway in one of my Filter to extract required information from Header and based upon that I am throwing exception or forwarding / verifying that request using <code>Feign Client</code>. Some time hystrix throw <code>HystrixRuntimeException</code> when it couldn't reach out to respective services or because of any other issues.   </p>
  
  <p>So What I want is:  </p>
  
  <ol>
  <li>Provide default fallback method for every forwarding request, so that I can read and process it accordingly.   </li>
  <li>Global Exception handling other than <code>@ControllerAdvice</code> since I am not providing any custom <code>@HystrixCommand</code> and Controller to call services (AOP based solution ?).   </li>
  <li>Is it possible to intercept every failed request and retry them for certain number of times ? Internally it might be happening but can I override this functionality and handle each failed request either because of <code>TimedOutException</code> or because of HttpConnectionPool exception ?   </li>
  </ol>
  
  <p><strong>Update</strong><br>
  Is it a good practice to provide own routing in Zuul gateway ? using <code>@RestController</code> and <code>@HystrixCommand</code> together ? (I think its a bad idea, because over the period of time we will end up with lots of controllers and hence actual use of intelligent routing wouldn't work as expected)</p>