SpringCloud-LoadBalancer: How to get Header from Request?

[alice-index]

I'm using SpringCloud-LoadBalancer and want to code a loadBalancer which select instance by header "x-area".Here is the code:

public class CustomLoadBalancer extends RoundRobinLoadBalancer{
...
...
    @Override
    public Mono<Response<ServiceInstance>> choose(Request request){
        DefaultRequestContext requestContext = (DefaultRequestContext) request.getContext();
        RequestData clientRequest = (RequestData) requestContext.getClientRequest();
        HttpHeaders headers = clientRequest.getFirst("x-area");
        .....
    }
...
...
}

But the requestContext.getClientRequest() cannot cast to RequestData,and here is the debug info:

The LoadBalancerRequestFactory$lambda cannot cast to RequestData,But the arg$2 is what I need,how can I get It? or There is another way which can get header?

[OlgaMaciaszek]

Hello @FaustPipeDream , that might or might not work depending on the RequestContext implementation used in the scenario.
Please provide a minimal, complete, verifiable example that reproduces the issue and I'll be able to verify this for you.

[alice-index]

LoadBalancerTest Here is the project can reproduces this issue.
And I found I can get Header when using Feign,But cannot get Header when using RestTemplate.

[OlgaMaciaszek]

Hello, @FaustPipeDream - yes, in fact in this case a DefaultRequestContext is created in place of DataRequestContext, hence the cast issue. Will refactor it so that DataRequestContext is created whenever possible.