title: Feign Client - Dynamic Authorization Header
body: <p>I have a service that gets http request with an authorization header.
  When processing the request, I want to use a Feign Client to query another service. The query to the other service should include the same authorization header.</p>
  
  <p>Currently I use a Filter to extract the authorization header from the incoming request, store the header in a ThreadLocal.
  When building the Feign Client I use a RequestInterceptor to read the authorization header from the ThreadLocal and put it into the request to the other service.</p>
  
  <p>This approach is not ideal, because when I start using things like RxJava or Hystrix, threads are changed while processing the request and I have to move the authorization header ThreadLocal from one thread to another.</p>
  
  <p>What are other options to solve this?
  One way that I am thinking about is to create a new FeignClient for each request, this way I would no longer need to store the authorization in a thread local. But is this a good idea?</p>