Spring Cloud - Ribbon在Zuul上实现灰度和版本测试

本文依赖ribbon实现在Spring Cloud中的灰度测试。

POM引入

Zuul及下游服务中均引入包

<!-- 实现灰度测试关键包 -->
    <dependency>
        <groupId>io.jmnarloch</groupId>
        <artifactId>ribbon-discovery-filter-spring-cloud-starter</artifactId>
        <version>2.1.0</version>
    </dependency>

Zuul服务开发

private void fixGray(UserInfo userInfo) {
        // 配置转发渠道，例如用户id
        if (isGrayer(userInfo.getUserId())) {
            RibbonFilterContextHolder.clearCurrentContext();
            //灰度标识
            RibbonFilterContextHolder.getCurrentContext().add("prod", "2");
            RibbonFilterContextHolder.getCurrentContext().add("prod", "1.0");
        } else {
            RibbonFilterContextHolder.clearCurrentContext();
            RibbonFilterContextHolder.getCurrentContext().add("prod", "1");
            RibbonFilterContextHolder.getCurrentContext().add("prod", "1.1");
        }
}

下游服务开发

添加版本拦截器

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        super.addInterceptors(registry);
        registry.addInterceptor(new VersionInterceptor());
    }

}

实现拦截器

public class VersionInterceptor extends HandlerInterceptorAdapter {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //清除现有数据，防止干扰
        RibbonFilterContextHolder.clearCurrentContext();
        String prod = request.getHeader("prod");
        String version = request.getHeader("version");
        if (!StringUtils.isEmpty(prod)&&!StringUtils.isEmpty(version)) {
            RibbonFilterContextHolder.getCurrentContext().add("prod", prod);
            RibbonFilterContextHolder.getCurrentContext().add("version", version);
        }

        return true;
    }
}

下游服务配置

eureka:
  instance:
    preferIpAddress: true
    instance-id: ${spring.cloud.client.ip-address}:${server.port}
    metadataMap: #元信息
      prod: 2 #灰度标识，1生产服务,2为灰度服务
      version: 1.1 #服务版本标识
  client:
    registerWithEureka: true
    fetchRegistry: true

注意事项

• 通过以上配置，启动各服务，可以实现灰度测试和版本测试
• 在网关依据灰度和版本请求标识，Ribbon利用各服务的元信息进行匹配，以实现过滤和负载
• 服务中必须配置相应的请求标识，否则该请求无法负载，将会报错
• 关闭组件，ribbon.filter.metadata.enabled=false #默认true

源码及原理分析

• 元信息筛选

  public class MetadataAwarePredicate extends DiscoveryEnabledPredicate {
  
      /**
       * {@inheritDoc}
       */
      @Override
      protected boolean apply(DiscoveryEnabledServer server) {
              
          //当前请求上下文
          final RibbonFilterContext context = RibbonFilterContextHolder.getCurrentContext();
          //当前请求属性
          final Set<Map.Entry<String, String>> attributes = Collections.unmodifiableSet(context.getAttributes().entrySet());
          //当前服务元信息
          final Map<String, String> metadata = server.getInstanceInfo().getMetadata();
          //服务元信息是否完全包含请求属性
          return metadata.entrySet().containsAll(attributes);
      }
  }

• 注册实例

  @Configuration
  @ConditionalOnClass(DiscoveryEnabledNIWSServerList.class)
  @AutoConfigureBefore(RibbonClientConfiguration.class)
  @ConditionalOnProperty(value = "ribbon.filter.metadata.enabled", matchIfMissing = true)
  public class RibbonDiscoveryRuleAutoConfiguration {
      
      //在Spring application context注册DiscoveryEnabledRule
      @Bean
      @ConditionalOnMissingBean
      @Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
      public DiscoveryEnabledRule metadataAwareRule() {
          //使用自定义元信息过滤
          return new MetadataAwareRule();
      }
  }

• 配置请求信息

  RibbonFilterContextHolder.getCurrentContext().add("version", "1.1").add("variant", "A");

  在zuul中配置，以便调取下游

  在下游拦截器中配置，以便当前服务继续调用下游服务

  也可以在RestTemplate的ClientHttpRequestInterceptor中配置