seata踩坑：zipkin整合seata的时候导致远程调用服务连接不上

迷南。 2022-12-07 11:39 246阅读 0赞

问题：在项目整合了集成了seata来做分布式事务，后面整合sleuth来做服务追踪后发现消费者使用feign调不通提供者服务了，当时检查了提供者服务都是否启动了，提供者是否注册nacos成功了，也检查了feign调用的提供者的在nacos上注册的服务名，这些都没有问题，就是使用feign调不通服务，就像提供者服务没有启动一样，我引入的依赖是**spring-cloud-alibaba-seata和spring-cloud-starter-zipkin,**一直报错：

Caused by: com.netflix.client.ClientException: Load balancer does not have available server for client: 192.168.248.1
      at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:483) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
      at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
      at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
      at rx.Observable.unsafeSubscribe(Observable.java:10327) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.Observable.subscribe(Observable.java:10423) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.Observable.subscribe(Observable.java:10390) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:443) ~[rxjava-1.3.8.jar:1.3.8]
      at rx.observables.BlockingObservable.single(BlockingObservable.java:340) ~[rxjava-1.3.8.jar:1.3.8]
      at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:112) ~[ribbon-loadbalancer-2.3.0.jar:2.3.0]
      at org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:83) ~[spring-cloud-openfeign-core-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    ... 120 common frames omitted

后面在seata官网的issue发现使用sleuth和seata同时存在，会导致feign调用报错，seata官网issue链接：

[https://github.com/seata/seata/issues/2544][https_github.com_seata_seata_issues_2544]

官网建议：

Spring Cloud Sleuth默认通过TraceFeignClientAutoConfiguration提供feign的集成，可以设置spring.sleuth.feign.enabled为false来使其无效

但是这种修改方式把sleuth关闭了，导致在zipkin控制台看到的接口调用栈都是没有任何关联的，

如果你需要使用seata，但是又不想关闭sleuth，则本篇博客就来解决这个问题。

**分布式系统中seata如何传递xid：**

在seata的官方文档中**业务系统集成seata客户端**，有五个步骤。在最后一个步骤：

> 步骤五：实现xid跨服务传递  
>     手动 参考源码integration文件夹下的各种rpc实现 module  
>     自动 springCloud用户可以引入spring-cloud-alibaba-seata，内部已经实现xid传递

这个意思也就是：**需要把全局事务的xid，透传到构成全局事务的各个子服务中。**

>     自动透传xid，可以直接引用 spring-cloud-alibaba-seata  （由于这个包和sleuth冲突，所以我们主要看手动透传xid的方案。）
> 
>     手动透传xid，可以参考官方源码的实现： [https://github.com/seata/seata/tree/develop/integration][https_github.com_seata_seata_tree_develop_integration]

**解决思路：**

这里我就以http的实现思路来简单说一下：

>     如果构成全局事务的各个自服务是使用http协议的，比如使用的是SpringCloud。对于http协议透传xid的方式很简单：
> 
>     **在consumer端，只需要获取到xid然后把xid放到请求头中；**
> 
> **    在provider端解析http的请求头，然后使用RootContext.bind(xid)绑定xid即可。**

**解决问题：**

在consumer端：

1.修改启动类，加(exclude = \{SeataFeignClientAutoConfiguration.class\})

@SpringBootApplication(exclude = {SeataFeignClientAutoConfiguration.class})

2.可以在每个feign请求头中将全局事务的xid传过去，本人推荐使用全局请求的头中加上xid，如：

import feign.RequestInterceptor;
    import feign.RequestTemplate;
    import io.seata.core.context.RootContext;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    
    public class SeataFeignInterceptor implements RequestInterceptor {
    
        private static final Logger logger = LoggerFactory.getLogger(SeataFeignInterceptor.class);
    
        @Override
        public void apply(RequestTemplate request) {
            String xid = RootContext.getXID();
    
            if (xid != null && !xid.trim().isEmpty()) {
                logger.info("seata - feign add seata-xid http request header [{}]", xid);
                request.header(RootContext.KEY_XID, xid);
            }
        }
    }

注册该拦截器

import com.db.cloud.serviceconsume.common.handle.SeataFeignInterceptor;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class CommonConfig {
    
        @Bean
        public SeataFeignInterceptor seataFeignInterceptor() {
            return new SeataFeignInterceptor();
        }
    }

在provider端，是否实现了WebMvcConfigurer,如果是,请参考com.alibaba.cloud.seata.web.SeataHandlerInterceptorConfiguration\#addInterceptors的方法.把SeataHandlerInterceptor加入到你的拦截链路中.因为在consumer在每个请求头加入了全局事务的xid，所以需要在拦截器中使用该xid，而seata使用http请求时使用的是SeataHandlerInterceptor，此时需在拦截链路中加入该拦截器，如何使用xid可以看看SeataHandlerInterceptor的源码。

WebMvcConfigurer配置添加SeataHandlerInterceptor如下：

import com.alibaba.cloud.seata.web.SeataHandlerInterceptor;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    
    @Configuration
    public class WebMvcConfig implements WebMvcConfigurer {
    
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(new SeataHandlerInterceptor()).addPathPatterns(new String[]{"/**"});
        }
    
    }

参考链接：

[https://github.com/seata/seata/issues/2544][https_github.com_seata_seata_issues_2544]

[https://seata.io/zh-cn/docs/overview/faq.html][https_seata.io_zh-cn_docs_overview_faq.html]

[https://github.com/seata/seata/tree/develop/integration/http/src/main/java/io/seata/integration/http][https_github.com_seata_seata_tree_develop_integration_http_src_main_java_io_seata_integration_http]

[https_github.com_seata_seata_issues_2544]: https://github.com/seata/seata/issues/2544
[https_github.com_seata_seata_tree_develop_integration]: https://github.com/seata/seata/tree/develop/integration
[https_seata.io_zh-cn_docs_overview_faq.html]: https://seata.io/zh-cn/docs/overview/faq.html
[https_github.com_seata_seata_tree_develop_integration_http_src_main_java_io_seata_integration_http]: https://github.com/seata/seata/tree/develop/integration/http/src/main/java/io/seata/integration/http