Spring Cloud Gateway 采用 OpenFeign 远程调用失败的解决方案

一、框架版本

• Spring Boot、 Spring Cloud 、 Spring Cloud Alibaba

  框架名称	框架版本
  Spring Boot	2.2.5.RELEASE
  Spring Cloud	Hoxton.SR3
  Spring Cloud Alibaba	2.2.1.RELEASE

二、源码展示

• 远程鉴权 Controller 控制器代码片段

  @RestController
  @Slf4j
  @RequestMapping("/security")
  public class AuthenticationController {
         
  
      @Resource
      private AuthenticationService authenticationService;
  
      @PostMapping("/auth")
      public Boolean checkAuth(@RequestBody @Valid BaseRequest baseRequest) {
         
          log.info("<-------------------------->");
          return authenticationService.checkAuth(baseRequest);
      }
  }
  

• 网关引用 OpenFeign 依赖

  
  
      org.springframework.cloud
      spring-cloud-starter-openfeign
      2.2.2.RELEASE
  
  

• 网关 OpenFeign 调用客户端

  @Component
  @FeignClient(value = "rms-security-service")
  public interface InvokeSecurityServiceClient {
         
  
      @PostMapping("/security/auth")
      Boolean checkAuth(BaseRequest baseRequest);
  }
  

三、问题描述

  在网关层进行统一鉴权和认证的过程中，需要远程调用鉴权服务器的接口进行鉴权的操作。但是在采用 OpenFiegn 进行远程调用的过程中，出现了如下的报错堆栈，导致了远程调用失败

• 堆栈信息

  feign.codec.EncodeException: No qualifying bean of type 'org.springframework.boot.autoconfigure.http.HttpMessageConverters' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {
         @org.springframework.beans.factory.annotation.Autowired(required=true)}
  	at feign.ReflectiveFeign$BuildEncodedTemplateFromArgs.resolve(ReflectiveFeign.java:384)
  	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
  Error has been observed at the following site(s):
  	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.AuthorizationWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.authorization.ExceptionTranslationWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.authentication.logout.LogoutWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.savedrequest.ServerRequestCacheWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.context.SecurityContextServerWebExchangeWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.authentication.AuthenticationWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.context.ReactorContextWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ cn.com.jstec.open.cloud.gateway.config.SecurityConfig$$Lambda$772/0x0000016c006c3040 [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.header.HttpHeaderWriterWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.config.web.server.ServerHttpSecurity$ServerWebExchangeReactorContextWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.security.web.server.WebFilterChainProxy [DefaultWebFilterChain]
  	|_ checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
  	|_ checkpoint ⇢ HTTP GET "/open-platform/achievement/list?page=1" [ExceptionHandlingWebHandler]
  Stack trace:
  

• 关键信息

  No qualifying bean of type 'org.springframework.boot.autoconfigure.http.HttpMessageConverters
  

四、解决方案

• 堆栈分析

  HttpMessageConverters 没有被注入到容器中管理

• ISSUES 跟踪

  点击此处 查看 issues 信息

• 解决方案

  1. 源码：HttpMessageConverters.java 中没有发现异常，于是开始查看是否存在 AutoConfiguration 打开 HttpMessageConvertersAutoConfiguration.java

     @Configuration(proxyBeanMethods = false)
     @ConditionalOnClass(HttpMessageConverter.class)
     @Conditional(NotReactiveWebApplicationCondition.class)
     @AutoConfigureAfter({
               GsonAutoConfiguration.class, JacksonAutoConfiguration.class, JsonbAutoConfiguration.class })
     @Import({
               JacksonHttpMessageConvertersConfiguration.class, GsonHttpMessageConvertersConfiguration.class,
     		JsonbHttpMessageConvertersConfiguration.class })
     public class HttpMessageConvertersAutoConfiguration {
              
     }
     

  2. 源码：@Conditional(NotReactiveWebApplicationCondition.class) @Conditional 是 Spring4 新提供的注解，它的作用是按照一定的条件进行判断，满足条件给容器注册 bean 再查看类 NotReactiveWebApplicationCondition

     static class NotReactiveWebApplicationCondition extends NoneNestedConditions {
              
     
     		NotReactiveWebApplicationCondition() {
              
     			super(ConfigurationPhase.PARSE_CONFIGURATION);
     		}
     
     		@ConditionalOnWebApplication(type = Type.REACTIVE)
     		private static class ReactiveWebApplication {
              
     
     		}
     
     	}
     

  3. Spring Cloud Gateway 是基于 WebFlux 的，是 ReactiveWeb，所以 HttpMessageConverters 不会自动注入。于是自己在配置文件中，直接复制源码的 Bean，最终成功。

     # 新建配置类
     @Configuration
     public class WebFluxWithOpenFeignConfig {
              
         @Bean
         @ConditionalOnMissingBean
         public HttpMessageConverters messageConverters(ObjectProvider<HttpMessageConverter<?>> converters) {
              
             return new HttpMessageConverters(converters.orderedStream().collect(Collectors.toList()));
         }
     }