Ability to configure feign.RequestInterceptor specific to a given feign client

[xyloman]

There is a few use cases where we need to add different headers or authentication mechanisms on a per client basis. Currently the FeignClientFactoryBean appears to apply its configuration to all feign clients that it constructs. This was problematic in that some services that we want to use feign for require a different set of RequestInterceptors to one set of clients verse another. Is there a way to accomplish this today? We were able to work around this issue by using the feign builder directly, with the only thing we are customizing is the list RequestInterceptor from the other FeignClients.

[spencergibb]

Good idea. We have a similar mechanism for @RibbonClient we could reuse.

[john-eevee]

Maybe we could register the RequestInterceptors through a value in @RibbonClient ? So it's clear which client use which interceptor

[spencergibb]

@joaoevangelista we need to maintain separation between Feign and Ribbon. I'm imagining the same type of facility that @RibbonClient uses for @FeignClient. We could probably generalize it for use with other annotations.

[john-eevee]

@spencergibb Really sorry! I meant @FeignClient, I got confused a bit, but yea, a generalized way would be nice too

[marcosbarbero]

Hi everybody, how is this issue going?

[dwelch2344]

Just wanted to throw in my vote on this. We've got a mixture of some ribbon backed FeignClients and a few that are hard coded to 3rd party APIs, so this would be a major win.

[spencergibb]

Yeah, I see this as our biggest feature for feign. I'm working on getting ready for a conference week after next, so it might not get started until after OSCON.

[sbuettner]

Same as @dwelch2344. Would really like to see support for that. Maybe by leveraging springs @qualifier annotation.

[lpborges]

This is exactly what I need.
I need to setup a FeignClient that use Basic Authentication, and this feature can help to setup a Feign BasicAuthRequestInterceptor different for each client.
Maybe some options for authentication on the FeignClient annotation can help too.

I figured to setup Authentication using headers in the RequestMapping:

@FeignClient(url="${service.url}")
public interface ProductsClient {

    @RequestMapping(method = RequestMethod.GET, value = "/item/{idProduct}", consumes = "application/json",
            headers="Authorization: Basic ${service.auth}")
    public ProductDTO getProduct(@PathVariable("idProduct") long idProduct);
}

But the problem is that the headers parameter don't apply the Spring value properties ( ${service.auth} ), so you need to hard code the authentication value.

[john-eevee]

For now, you can create a bean of feign.RequestInterceptor returning a BasicAuthRequestInterceptor or implement your own, like I did for OAuth2 here. It will be applied to all requests using feign