Feign client with custom Configuration (custom RequestInterceptor) picking up another client Configuration (RequestInterceptor)

Hi,

This seems to be a bug, given that this is suppose to be supported as of #288.

I am currently using Spring Boot 2.0.0.RC2 with Spring Cloud Finchley.M7.

I have two Feign clients, each with a custom Feign Configuration class adding a custom RequestInterceptor. One RequestInterceptor adds a header for auth and another is an expensive one because it does all the OAuth2 Authorization Code flow.

@FeignClient(name = "gAuthifyApiClient", url = "{gAuthifyUrl}", configuration = GAuthifyApiClient.FeignClientConfiguration.class, decode404 = true)
public interface GAuthifyApiClient {
...
    @Configuration("gAuthifyFeignClientConfiguration")
    class FeignClientConfiguration {
        @Bean
        public BasicAuthRequestInterceptor basicAuthRequestInterceptor(@Value("${gauthify.api.key}") String apiKey) {
            return new BasicAuthRequestInterceptor("", apiKey);
        }
    }
...
}

@FeignClient(name = "profileIdApiClient", url = "{profileIdUrl}", configuration = ProfileIdApiClient.FeignClientConfiguration.class, decode404 = true)
public interface ProfileIdApiClient {
...
    @Configuration("profileIdFeignClientConfiguration")
    class FeignClientConfiguration {

        @Bean
        public BearerHeaderAuthRequestInterceptor bearerHeaderAuthRequestInterceptor() {
            return new BearerHeaderAuthRequestInterceptor();
        }
    }
...
    class BearerHeaderAuthRequestInterceptor implements RequestInterceptor {
       //Expensive OAuth2 flow logic
    }
...
}

The problem is that the client that uses the former (header auth) is picking up both interceptors. Hence, when using the first client, both interceptors are triggered.

I did some debugging and it seems it has to do with the hierarchical nature of the FactoryBean used to search for RequestInterceptors for the named factory bean.

More specifically…

FeignClientFactoryBean.configureUsingConfiguration(...) {
...
   Map<String, RequestInterceptor> requestInterceptors = **context.getInstances**(this.name, RequestInterceptor.class);
...
}

NamedContextFactory.**getInstances**(String name, Class<T> type) {
	AnnotationConfigApplicationContext context = getContext(name);
	if (BeanFactoryUtils.beanNamesForTypeIncludingAncestors(context, type).length > 0) {
		return **BeanFactoryUtils.beansOfTypeIncludingAncestors(context, type);**
	}
	return null;
}

**BeanFactoryUtils.beansOfTypeIncludingAncestors(ListableBeanFactory lbf, Class<T> type)**
			throws BeansException {
		Assert.notNull(lbf, "ListableBeanFactory must not be null");
		Map<String, T> result = new LinkedHashMap<>(4);
		result.putAll(lbf.getBeansOfType(type));
		**if (lbf instanceof HierarchicalBeanFactory)** {
			HierarchicalBeanFactory hbf = (HierarchicalBeanFactory) lbf;
			if (hbf.getParentBeanFactory() instanceof ListableBeanFactory) {
				Map<String, T> parentResult = beansOfTypeIncludingAncestors(
						(ListableBeanFactory) hbf.getParentBeanFactory(), type);
				parentResult.forEach((beanName, beanType) -> {
					if (!result.containsKey(beanName) && !hbf.containsLocalBean(beanName)) {
						result.put(beanName, beanType);
					}
				});
			}
		}
		return result;
	}

Any ideas? Is this already supported in the specified version?

Thanks in advance!