devbox
Guff_9hys
这个屌丝很懒，什么也没留下！
关注作者
热门标签
热门文章
当前位置:   article > 正文

eureka监听各服务状态，下线、重连等，并做相应的处理_eureka-server 熔断

作者：Guff_9hys | 2024-07-13 07:26:44

赞

踩

eureka-server 熔断

在一些场景下，我们需要监听eureka服务中心的一些状态，譬如某个微服务挂掉了，我们希望能监听到，并给管理员发送邮件通知。

Eureka的server端会发出5个事件通知，分别是：

EurekaInstanceCanceledEvent 服务下线事件
EurekaInstanceRegisteredEvent 服务注册事件
EurekaInstanceRenewedEvent 服务续约事件
EurekaRegistryAvailableEvent Eureka注册中心启动事件
EurekaServerStartedEvent Eureka Server启动事件

我们可以从源码中很方便地看到

eureka的server端源码一共也没几个类，Controller是给界面用的，还有一些配置类，我们简单来看几个。


  1. @Configuration
  2. @CommonsLog
  3. public class EurekaServerInitializerConfiguration
  4.         implements ServletContextAware, SmartLifecycle, Ordered {
  5.  
  6.     ...
  7.  
  8.     @Override
  9.     public void start() {
  10.         new Thread(new Runnable() {
  11.             @Override
  12.             public void run() {
  13.                 try {
  14.                     //TODO: is this class even needed now?
  15.                     // 初始化eureka server
  16.                     eurekaServerBootstrap.contextInitialized(EurekaServerInitializerConfiguration.this.servletContext);
  17.                     log.info("Started Eureka Server");
  18.  
  19.                     // 传递eureka注册事件，找来找去没看到有listen去处理这件事件
  20.                     // spring包中没有去处理，如果我们有需要可以自己处理
  21.                     // https://github.com/spring-cloud/spring-cloud-netflix/issues/1726
  22.                     publish(new EurekaRegistryAvailableEvent(getEurekaServerConfig()));
  23.                     // 设置在spring容器关闭的时候执行stop方法
  24.                     EurekaServerInitializerConfiguration.this.running = true;
  25.                     publish(new EurekaServerStartedEvent(getEurekaServerConfig()));
  26.                 }
  27.                 catch (Exception ex) {
  28.                     // Help!
  29.                     log.error("Could not initialize Eureka servlet context", ex);
  30.                 }
  31.             }
  32.         }).start();
  33.     }
  34.  
  35.  
  36.     @Bean
  37.     public EurekaServerBootstrap eurekaServerBootstrap(PeerAwareInstanceRegistry registry,
  38.             EurekaServerContext serverContext) {
  39.         return new EurekaServerBootstrap(this.applicationInfoManager,
  40.                 this.eurekaClientConfig, this.eurekaServerConfig, registry,
  41.                 serverContext);
  42.     }
  43.     ...
  44. }

  1. @CommonsLog
  2. public class EurekaServerBootstrap {
  3.  
  4.     ....
  5.  
  6.     public void contextInitialized(ServletContext context) {
  7.         try {
  8.             //初始化eureka环境
  9.             initEurekaEnvironment();
  10.             //初始化eureka上下文
  11.             initEurekaServerContext();
  12.  
  13.             context.setAttribute(EurekaServerContext.class.getName(), this.serverContext);
  14.         }
  15.         catch (Throwable e) {
  16.             log.error("Cannot bootstrap eureka server :", e);
  17.             throw new RuntimeException("Cannot bootstrap eureka server :", e);
  18.         }
  19.     }
  20.  
  21.     protected void initEurekaEnvironment() throws Exception {
  22.         log.info("Setting the eureka configuration..");
  23.  
  24.         //如果在云环境中运行，需要传递java命令行属性-Deureka.datacenter = cloud，以便Eureka客户端/服务器知道初始化AWS云特定的信息
  25.         String dataCenter = ConfigurationManager.getConfigInstance()
  26.                 .getString(EUREKA_DATACENTER);
  27.         if (dataCenter == null) {
  28.             log.info(
  29.                     "Eureka data center value eureka.datacenter is not set, defaulting to default");
  30.             ConfigurationManager.getConfigInstance()
  31.                     .setProperty(ARCHAIUS_DEPLOYMENT_DATACENTER, DEFAULT);
  32.         }
  33.         else {
  34.             ConfigurationManager.getConfigInstance()
  35.                     .setProperty(ARCHAIUS_DEPLOYMENT_DATACENTER, dataCenter);
  36.         }
  37.  
  38.         //eureka 运行环境，java命令行属性-Deureka.environment=eureka-client-{test，prod}
  39.         String environment = ConfigurationManager.getConfigInstance()
  40.                 .getString(EUREKA_ENVIRONMENT);
  41.         if (environment == null) {
  42.             ConfigurationManager.getConfigInstance()
  43.                     .setProperty(ARCHAIUS_DEPLOYMENT_ENVIRONMENT, TEST);
  44.             log.info(
  45.                     "Eureka environment value eureka.environment is not set, defaulting to test");
  46.         }
  47.         else {
  48.             ConfigurationManager.getConfigInstance()
  49.                     .setProperty(ARCHAIUS_DEPLOYMENT_ENVIRONMENT, environment);
  50.         }
  51.     }
  52.  
  53.     // eureka使用XStream来对json、xml格式的转换
  54.     protected void initEurekaServerContext() throws Exception {
  55.         // 向后兼容
  56.         //注册状态转换器
  57.         JsonXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
  58.                 XStream.PRIORITY_VERY_HIGH);
  59.         XmlXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
  60.                 XStream.PRIORITY_VERY_HIGH);
  61.  
  62.         //判断是否亚马逊的数据中心
  63.         if (isAws(this.applicationInfoManager.getInfo())) {
  64.             this.awsBinder = new AwsBinderDelegate(this.eurekaServerConfig,
  65.                     this.eurekaClientConfig, this.registry, this.applicationInfoManager);
  66.             //
  67.             this.awsBinder.start();
  68.         }
  69.  
  70.         //初始化eureka server上下文
  71.         EurekaServerContextHolder.initialize(this.serverContext);
  72.  
  73.         log.info("Initialized server context");
  74.  
  75.         // 从相邻的eureka节点复制注册表
  76.         int registryCount = this.registry.syncUp();
  77.         // 默认每30秒发送心跳，1分钟就是2次
  78.         // 修改eureka状态为up
  79.         this.registry.openForTraffic(this.applicationInfoManager, registryCount);
  80.  
  81.         // 注册所有监控
  82.         EurekaMonitors.registerAllStats();
  83.     }
  84.  
  85.     ...
  86. }

  1. public class InstanceRegistry extends PeerAwareInstanceRegistryImpl implements ApplicationContextAware {
  2.     private static final Log log = LogFactory.getLog(InstanceRegistry.class);
  3.     private ApplicationContext ctxt;
  4.     private int defaultOpenForTrafficCount;
  5.  
  6.     public InstanceRegistry(EurekaServerConfig serverConfig, EurekaClientConfig clientConfig, ServerCodecs serverCodecs, EurekaClient eurekaClient, int expectedNumberOfRenewsPerMin, int defaultOpenForTrafficCount) {
  7.         super(serverConfig, clientConfig, serverCodecs, eurekaClient);
  8.         this.expectedNumberOfRenewsPerMin = expectedNumberOfRenewsPerMin;
  9.         this.defaultOpenForTrafficCount = defaultOpenForTrafficCount;
  10.     }
  11.  
  12.     public void setApplicationContext(ApplicationContext context) throws BeansException {
  13.         this.ctxt = context;
  14.     }
  15.  
  16.     public void openForTraffic(ApplicationInfoManager applicationInfoManager, int count) {
  17.         super.openForTraffic(applicationInfoManager, count == 0 ? this.defaultOpenForTrafficCount : count);
  18.     }
  19.  
  20.     public void register(InstanceInfo info, int leaseDuration, boolean isReplication) {
  21.         this.handleRegistration(info, leaseDuration, isReplication);
  22.         super.register(info, leaseDuration, isReplication);
  23.     }
  24.  
  25.     public void register(InstanceInfo info, boolean isReplication) {
  26.         this.handleRegistration(info, this.resolveInstanceLeaseDuration(info), isReplication);
  27.         super.register(info, isReplication);
  28.     }
  29.  
  30.     public boolean cancel(String appName, String serverId, boolean isReplication) {
  31.         this.handleCancelation(appName, serverId, isReplication);
  32.         return super.cancel(appName, serverId, isReplication);
  33.     }
  34.  
  35.     public boolean renew(String appName, String serverId, boolean isReplication) {
  36.         this.log("renew " + appName + " serverId " + serverId + ", isReplication {}" + isReplication);
  37.         List<Application> applications = this.getSortedApplications();
  38.         Iterator var5 = applications.iterator();
  39.  
  40.         while(var5.hasNext()) {
  41.             Application input = (Application)var5.next();
  42.             if (input.getName().equals(appName)) {
  43.                 InstanceInfo instance = null;
  44.                 Iterator var8 = input.getInstances().iterator();
  45.  
  46.                 while(var8.hasNext()) {
  47.                     InstanceInfo info = (InstanceInfo)var8.next();
  48.                     if (info.getId().equals(serverId)) {
  49.                         instance = info;
  50.                         break;
  51.                     }
  52.                 }
  53. 		//这里发布重连事件
  54.                 this.publishEvent(new EurekaInstanceRenewedEvent(this, appName, serverId, instance, isReplication));
  55.                 break;
  56.             }
  57.         }
  58.  
  59.         return super.renew(appName, serverId, isReplication);
  60.     }
  61.  
  62.     protected boolean internalCancel(String appName, String id, boolean isReplication) {
  63.         this.handleCancelation(appName, id, isReplication);
  64.         return super.internalCancel(appName, id, isReplication);
  65.     }
  66.  
  67.     private void handleCancelation(String appName, String id, boolean isReplication) {
  68.         this.log("cancel " + appName + ", serverId " + id + ", isReplication " + isReplication);
  69.         this.publishEvent(new EurekaInstanceCanceledEvent(this, appName, id, isReplication));
  70.     }
  71.  
  72.     private void handleRegistration(InstanceInfo info, int leaseDuration, boolean isReplication) {
  73.         this.log("register " + info.getAppName() + ", vip " + info.getVIPAddress() + ", leaseDuration " + leaseDuration + ", isReplication " + isReplication);
  74.         this.publishEvent(new EurekaInstanceRegisteredEvent(this, info, leaseDuration, isReplication));
  75.     }
  76.  
  77.     private void log(String message) {
  78.         if (log.isDebugEnabled()) {
  79.             log.debug(message);
  80.         }
  81.  
  82.     }
  83.  
  84.     private void publishEvent(ApplicationEvent applicationEvent) {
  85.         this.ctxt.publishEvent(applicationEvent);
  86.     }
  87.  
  88.     private int resolveInstanceLeaseDuration(InstanceInfo info) {
  89.         int leaseDuration = 90;
  90.         if (info.getLeaseInfo() != null && info.getLeaseInfo().getDurationInSecs() > 0) {
  91.             leaseDuration = info.getLeaseInfo().getDurationInSecs();
  92.         }
  93.  
  94.         return leaseDuration;
  95.     }
  96. }
差不多能用上的就这几个类了，这5个server端事件在这几个类中都能找到。

知道了事件名，要监听就很简单了

  1. package com.tianyalei.server;
  2.  
  3. import com.netflix.appinfo.InstanceInfo;
  4. import org.springframework.cloud.netflix.eureka.server.event.EurekaInstanceCanceledEvent;
  5. import org.springframework.cloud.netflix.eureka.server.event.EurekaInstanceRegisteredEvent;
  6. import org.springframework.cloud.netflix.eureka.server.event.EurekaInstanceRenewedEvent;
  7. import org.springframework.cloud.netflix.eureka.server.event.EurekaRegistryAvailableEvent;
  8. import org.springframework.cloud.netflix.eureka.server.event.EurekaServerStartedEvent;
  9. import org.springframework.context.event.EventListener;
  10. import org.springframework.stereotype.Component;
  11.  
  12. /**
  13.  * Created by wuweifeng on 2017/10/10.
  14.  */
  15. @Component
  16. public class EurekaStateChangeListener {
  17.     
  18.     @EventListener
  19.     public void listen(EurekaInstanceCanceledEvent eurekaInstanceCanceledEvent) {
  20.         //服务断线事件
  21.         String appName = eurekaInstanceCanceledEvent.getAppName();
  22.         String serverId = eurekaInstanceCanceledEvent.getServerId();
  23.         System.out.println(appName);
  24.         System.out.println(serverId);
  25.     }
  26.  
  27.     @EventListener
  28.     public void listen(EurekaInstanceRegisteredEvent event) {
  29.         InstanceInfo instanceInfo = event.getInstanceInfo();
  30.         System.out.println(instanceInfo);
  31.     }
  32.  
  33.     @EventListener
  34.     public void listen(EurekaInstanceRenewedEvent event) {
  35.         event.getAppName();
  36.         event.getServerId();
  37.     }
  38.  
  39.     @EventListener
  40.     public void listen(EurekaRegistryAvailableEvent event) {
  41.  
  42.     }
  43.  
  44.     @EventListener
  45.     public void listen(EurekaServerStartedEvent event) {
  46.         //Server启动
  47.     }
  48. }
在server项目里加上这个监听类，然后在各个事件被触发时就能在这里监听并处理了。

譬如我启动一个client

在这里就能看到新注册的client的各项详细信息。
然后我再关掉client


可以看到挂掉的client的appName，serverId等信息。那么我们就可以在这里做一些处理，譬如邮件通知管理员，某某服务挂掉了。



声明：本文内容由网友自发贡献，不代表【wpsshop博客】立场，版权归原作者所有，本站不承担相应法律责任。如您发现有侵权的内容，请联系我们。转载请注明出处：https://www.wpsshop.cn/w/Guff_9hys/article/detail/818261
推荐阅读
相关标签

Copyright © 2003-2013 www.wpsshop.cn 版权所有，并保留所有权利。

  

闽ICP备14008679号