Spring Cloud 學習紀要九：Sleuth

Spring Cloud Sleuth：鏈路跟蹤

  Spring Cloud Sleuth是一種分佈式追蹤解決方案，它兼容Zipkin。微服務架構由於服務單元數量衆多、調用關係雜亂、業務複雜，如果出現了錯誤和異常很難去定位，所以微服務架構中，必須實現分佈式鏈路追蹤，去跟進一個請求到底有哪些服務參與，參與的順序又是怎樣的，讓每個請求步驟直觀可見，而 Sleuth + Zipkin 便可以幫助我們做到這樣的事情。

開發環境	版本
IDEA	2018.2.6
JDK	1.8
Spring Boot	2.0.6
Spring Cloud	Finchley.SR2
Docker	18.09.0
Zipkin	–

Zipkin 容器搭建

  Docker下執行一個命令就好，開啓服務後訪問http://localhost:9411/zipkin/可以看到如下界面。

依賴添加

  provider項目和consumer項目添加如下Maven依賴，特別注意：，因爲我這邊一直下載不到2.0.2的包，不知道是不是我的IDE的問題，將版本改爲2.1.0.M2。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zipkin</artifactId>
    <version>2.1.0.M2</version>
</dependency>

配置文件修改

  provider項目和consumer項目添加如下配置：

spring:
  zipkin:
    base-url: http://localhost:9411/
    sender:
      type: web
  sleuth:
    sampler:
      probability: 1
logging:
  level:
    org.springframework.cloud.openfeign: debug

鏈路跟蹤測試

  訪問consumer的接口http://localhost:8091/hello/consume?num=1，發現consumer項目控制檯會打印如下日誌，注意cde8ad1de4f90441。

2018-11-26 21:26:23.946  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] s.c.a.AnnotationConfigApplicationContext : Refreshing SpringClientFactory-provider: startup date [Mon Nov 26 21:26:23 CST 2018]; parent: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@777d0bc3
2018-11-26 21:26:24.009  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
2018-11-26 21:26:24.236  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: provider.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-11-26 21:26:24.254  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-provider
2018-11-26 21:26:24.279  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.netflix.loadbalancer.BaseLoadBalancer  : Client: provider instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=provider,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2018-11-26 21:26:24.284  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2018-11-26 21:26:24.313  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: provider.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-11-26 21:26:24.315  INFO [consumer,cde8ad1de4f90441,e3c14617dff44d76,true] 12488 --- [trix-provider-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client provider initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=provider,current list of Servers=[192.168.99.1:8081],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone;	Instance count:1;	Active connections count: 0;	Circuit breaker tripped count: 0;	Active connections per server: 0.0;]
},Server stats: [[Server:192.168.99.1:8081;	Zone:defaultZone;	Total Requests:0;	Successive connection failure:0;	Total blackout seconds:0;	Last connection made:Thu Jan 01 08:00:00 CST 1970;	First connection made: Thu Jan 01 08:00:00 CST 1970;	Active Connections:0;	total failure count in last (1000) msecs:0;	average resp time:0.0;	90 percentile resp time:0.0;	95 percentile resp time:0.0;	min resp time:0.0;	max resp time:0.0;	stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@7900120d

  訪問Zipkin頁面，查詢consumer項目的調用鏈：

  點擊某一行即可查看該調用的詳細信息，包括其traceIdcde8ad1de4f90441。

總結

  至此《Spring Cloud 學習紀要》系列博客就結束了，本系列博客介紹了包含服務治理組件Eureka、服務通信組件Feign、負載均衡組件Ribbon、配置中心組件Config、消息總線組件Bus、消息驅動組件Stream、統一網關組件Zuul、熔斷降級組件Hystrix、鏈路跟蹤組件Sleuth，此係列博客只適合入門小白，是一套極簡教程，更多知識待您親自探索。

組件	功能	同類框架
Spring Cloud Eureka	服務治理	ZooKeeper、Consul
Spring Cloud Feign	服務通信	Retrofit、OKHttp、HttpClient
Spring Cloud Ribbon	負載均衡	Nginx
Spring Cloud Config	配置中心	Consul
Spring Cloud Bus	消息總線
Spring Cloud Stream	消息驅動
Spring Cloud Zuul	統一網關	Janus、Spring Cloud Gateway
Spring Cloud Hystrix	熔斷降級
Spring Cloud Sleuth	鏈路跟蹤	Zipkin、Pinpoint