spring-cloud - 在运行时更改 FeignClient url

Question

拥有 Feign 客户端：

@FeignClient(name = "storeClient", url = "${feign.url}")
public interface StoreClient {
    //..
}

是否可以利用 Spring Cloud 的环境更改功能在运行时更改 Feign url？（更改feign.url属性并调用/refresh端点）

Answer 1

作为一种可能的解决方案 -RequestInterceptor可以引入以便RequestTemplate从RefreshScope.

要实施这种方法，您应该执行以下操作：

1. ConfigurationProperties Component中定义RefreshScope

   @Component
   @RefreshScope
   @ConfigurationProperties("storeclient")
   public class StoreClientProperties {
       private String url;
       ...
   }
   

2. 指定客户端的默认 URLapplication.yml

   storeclient
       url: https://someurl
   

3. 定义RequestInterceptor将切换 URL

   @Configuration
   public class StoreClientConfiguration {
   
       @Autowired
       private StoreClientProperties storeClientProperties;
   
       @Bean
       public RequestInterceptor urlInterceptor() {
           return template -> template.insert(0, storeClientProperties.getUrl());
       }
   
   }
   

4. 在 URL的定义中使用一些占位符FeignClient，因为它不会被使用

   @FeignClient(name = "storeClient", url = "NOT_USED")
   public interface StoreClient {
       //..
   }
   

现在storeclient.url可以刷新，定义的 URL 将用于RequestTemplate发送 http 请求。

Answer 2

有点扩展的答案RequestInterceptor：

1. application.yml

app:
  api-url: http://external.system/messages
  callback-url: http://localhost:8085/callback

2. @ConfigurationProperties

@Component
@RefreshScope
@ConfigurationProperties("app")
public class AppProperties {
    private String apiUrl;
    private String callbackUrl;
    ...
}

3. @FeignClient-s 配置

确保您的...ClientConfig类没有使用任何@Component/... 注释进行注释或被组件扫描发现。

public class ApiClientConfig {
    @Bean
    public RequestInterceptor requestInterceptor(AppProperties appProperties) {
        return requestTemplate -> requestTemplate.target(appProperties.getApiUrl());
    }
}

public class CallbackClientConfig {
    @Bean
    public RequestInterceptor requestInterceptor(AppProperties appProperties) {
        return requestTemplate -> requestTemplate.target(appProperties.getCallbackUrl());
    }
}

4. @FeignClient-s

@FeignClient(name = "apiClient", url = "NOT_USED", configuration = ApiClientConfig.class)
public interface ApiClient {
    ...
}

@FeignClient(name = "callbackClient", url = "NOT_USED", configuration = CallbackClientConfig.class)
public interface CallbackClient {
    ...
}