在运行时更改 FeignClient URL

Question

具有假装客户端：

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

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

Answer 1

作为一种可能的解决方案 - 可以引入RequestInterceptor以便从RefreshScope中定义的属性RequestTemplate中设置 URL。

要实现此方法，应执行以下操作：

1. 在RefreshScope中定义ConfigurationPropertiesComponent

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

2. 在application.yml中指定客户端的默认 URL

   storeclient
   url: https://someurl
   

3. 定义将切换 URL 的RequestInterceptor

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

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

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

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

Answer 2

一个扩展的答案，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类没有注释任何@Component/...注释或由组件扫描找到。

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 {
...
}