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Erueka状态变更说明(十三)

时间:2019-08-05 22:13:12来源:IT技术作者:seo实验室小编阅读:81次「手机版」
　

eru

状态说明

STARTING ： 表示服务正在启动中

DOWN： 表示服务已经宕机，无法继续提供服务

UP ： 服务正常运行

OUT_OF_SERVICE : 不再提供服务，其他的Eureka Client将调用不到该服务，一般有人为的调用接口设置的，如：强制下线。

UNKNOWN： 未知状态

状态变更

容器启动

在容器刚刚启动，实例化instance信息的时候，默认状态为STARTING

@Bean
@conditionalOnMissingBean(value = APPlicationInfoManager.class, search = SearchStrategy.CURRENT)
@org.Springframework.cloud.context.config.annotation.RefreshScope
@Lazy
public ApplicationInfoManager eurekaApplicationInfoManager(EurekainstanceConfig config) {
   InstanceInfo instanceInfo = new InstanceInfoFactory().create(config);
   return new ApplicationInfoManager(config, instanceInfo);
}
@ConditionalOnMissingBean(value = ApplicationInfoManager.class, search = SearchStrategy.CURRENT)
@org.springframework.cloud.context.config.annotation.RefreshScope
@Lazy
public ApplicationInfoManager eurekaApplicationInfoManager(EurekaInstanceConfig config) {
   InstanceInfo instanceInfo = new InstanceInfoFactory().create(config);
   return new ApplicationInfoManager(config, instanceInfo);
}

初始化ApplicationInfoManager的时候，会设置一个最初的Instance信息，这个时候的instance信息的状态为STARTING

public InstanceInfo create(EurekaInstanceConfig config) {
   leaseInfo.builder leaseInfoBuilder = LeaseInfo.Builder.newBuilder()
         .setRenewalIntervalInSecs(config.getLeaseRenewalIntervalInSeconds())
         .setDurationInSecs(config.getLeaseExpirationDurationInSeconds());
​
  
   InstanceInfo.Builder builder = InstanceInfo.Builder.newBuilder();
​
  // ..... 省略N多代码
  // config.isInstanceEnabledOnit() 默认为false
  if (!config.isInstanceEnabledOnit()) {
      // 设置实例的状态为STARTING
      InstanceInfo.InstanceStatus initialStatus = InstanceInfo.InstanceStatus.STARTING;
      if (log.isInfoEnabled()) {
         log.info("Setting initial instance status as: " + initialStatus);
      }
      builder.setStatus(initialStatus);
   }
   // ..... 省略N多代码
   InstanceInfo instanceInfo = builder.build();
   instanceInfo.setLeaseInfo(leaseInfoBuilder.build());
   return instanceInfo;
} InstanceInfo create(EurekaInstanceConfig config) {
   LeaseInfo.Builder leaseInfoBuilder = LeaseInfo.Builder.newBuilder()
         .setRenewalIntervalInSecs(config.getLeaseRenewalIntervalInSeconds())
         .setDurationInSecs(config.getLeaseExpirationDurationInSeconds());
​
  
   InstanceInfo.Builder builder = InstanceInfo.Builder.newBuilder();
​
  // ..... 省略N多代码
  // config.isInstanceEnabledOnit() 默认为false
  if (!config.isInstanceEnabledOnit()) {
      // 设置实例的状态为STARTING
      InstanceInfo.InstanceStatus initialStatus = InstanceInfo.InstanceStatus.STARTING;
      if (log.isInfoEnabled()) {
         log.info("Setting initial instance status as: " + initialStatus);
      }
      builder.setStatus(initialStatus);
   }
   // ..... 省略N多代码
   InstanceInfo instanceInfo = builder.build();
   instanceInfo.setLeaseInfo(leaseInfoBuilder.build());
   return instanceInfo;
}

上面的代码是做了一些初始化的信息，设置Instance的状态为STARTING，接下来，在自动注册类初始化的时候，

会设置Instance的状态为UP，同时触发监听器，让Eureka Client发起注册。


@Bean
@ConditionalOnBean(AutoServiceRegistrationProperties.class)
@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled", matchIfMissing = true)
public EurekaAutoServiceRegistration eurekaAutoServiceRegistration(ApplicationContext context, EurekaServiceRegistry registry, EurekaRegistration registration) {
   return new EurekaAutoServiceRegistration(context, registry, registration);
}@Bean
@ConditionalOnBean(AutoServiceRegistrationProperties.class)
@ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled", matchIfMissing = true)
public EurekaAutoServiceRegistration eurekaAutoServiceRegistration(ApplicationContext context, EurekaServiceRegistry registry, EurekaRegistration registration) {
   return new EurekaAutoServiceRegistration(context, registry, registration);
}

流程图如下：

1528437997(1).jpg

关于容器启动时注册的具体细节，可以细看https://blog.csdn.net/u012394095/article/details/80693713中自动注册那一小结

健康检查器

在Eureka Client端，有一个40秒执行一次的定时任务，会定时的去扫描自身的信息，查看自身信息是否发生改变，

其中就有一个对状态的检测，这个时候，如果设置了健康检查器，那么会以健康检查的结果为准，判断当前实例的

状态


// DiscoverClient.java
void refreshInstanceInfo() {
    // 1. 判断数据中心的数据是否发生改变，
    applicationInfoManager.refreshDataCenterInfoIfrequired();
    // 2.判断配置是否发生改变
    applicationInfoManager.refreshLeaseInfoIfRequired();
 
    InstanceStatus status;
    try {
        // 通过健康检查器，获取应用的最新状态
        status = getHealthCheckhandler().getStatus(instanceInfo.getStatus());
    } catch (Exception e) {
        logger.warn("Exception from healthcheckHandler.getStatus, setting status to DOWN", e);
        status = InstanceStatus.DOWN;
    }
 
    if (null != status) {
        // 设置状态
        applicationInfoManager.setInstanceStatus(status);
    }
}// DiscoverClient.java
void refreshInstanceInfo() {
    // 1. 判断数据中心的数据是否发生改变，
    applicationInfoManager.refreshDataCenterInfoIfRequired();
    // 2.判断配置是否发生改变
    applicationInfoManager.refreshLeaseInfoIfRequired();
 
    InstanceStatus status;
    try {
        // 通过健康检查器，获取应用的最新状态
        status = getHealthCheckHandler().getStatus(instanceInfo.getStatus());
    } catch (Exception e) {
        logger.warn("Exception from healthcheckHandler.getStatus, setting status to DOWN", e);
        status = InstanceStatus.DOWN;
    }
 
    if (null != status) {
        // 设置状态
        applicationInfoManager.setInstanceStatus(status);
    }
}

健康检查器，获取状态。


@Override
    public InstanceInfo.InstanceStatus getStatus(InstanceInfo.InstanceStatus currentStatus) {
        // 判断instance的状态。
        if (null == callback || InstanceInfo.InstanceStatus.STARTING == currentStatus
                || InstanceInfo.InstanceStatus.OUT_OF_SERVICE == currentStatus) { // Do not go to healthcheck handler if the status is starting or OOS.
            return currentStatus;
        }
​
        return callback.isHealthy() ? InstanceInfo.InstanceStatus.UP : InstanceInfo.InstanceStatus.DOWN;
    }@Override
    public InstanceInfo.InstanceStatus getStatus(InstanceInfo.InstanceStatus currentStatus) {
        // 判断instance的状态。
        if (null == callback || InstanceInfo.InstanceStatus.STARTING == currentStatus
                || InstanceInfo.InstanceStatus.OUT_OF_SERVICE == currentStatus) { // Do not go to healthcheck handler if the status is starting or OOS.
            return currentStatus;
        }
​
        return callback.isHealthy() ? InstanceInfo.InstanceStatus.UP : InstanceInfo.InstanceStatus.DOWN;
    }

代码如上，如果callback对象不为空的话，那么会调用callback的isHealthy()方法判断实例的状态。

同时会将获取到的状态调用 applicationInfoManager.setInstanceStatus(status) ， 只有当传入的

状态和他本身的状态不一致时，才会更新， 如果更新了状态，那么同时也会想服务器注册最新的信息

具体可以看 ：https://blog.csdn.net/u012394095/article/details/80966441

强制下线

下篇讲解

容器销毁

在使用kill pid 这种方式去终止进程的时候，spring容器会销毁，在销毁的时候会触发一些shutDown这种方法。

EurekaAutoServiceRegistration是一个实现了SmartLifecycle的接口类，在spring容器销毁的时候，会调用其

stop方法。


@Override
public void stop() {
   this.serviceRegistry.deregister(this.registration);
   this.running.set(false);
}@Override
public void stop() {
   this.serviceRegistry.deregister(this.registration);
   this.running.set(false);
}

调用了deregister方法，


@Override
public void deregister(EurekaRegistration reg) {
   if (reg.getApplicationInfoManager().getInfo() != null) {
​
      if (log.isInfoEnabled()) {
         log.info("Unregistering application " + reg.getInstanceConfig().getAppname()
               + " with eureka with status DOWN");
      }
      // 设置实例的状态为DOWN
      reg.getApplicationInfoManager().setInstanceStatus(InstanceInfo.InstanceStatus.DOWN);
​
      //触发DiscoverClient的shutdown方法
      reg.getEurekaClient().shutdown();
   }
}@Override
public void deregister(EurekaRegistration reg) {
   if (reg.getApplicationInfoManager().getInfo() != null) {
​
      if (log.isInfoEnabled()) {
         log.info("Unregistering application " + reg.getInstanceConfig().getAppname()
               + " with eureka with status DOWN");
      }
      // 设置实例的状态为DOWN
      reg.getApplicationInfoManager().setInstanceStatus(InstanceInfo.InstanceStatus.DOWN);
​
      //触发DiscoverClient的shutdown方法
      reg.getEurekaClient().shutdown();
   }
}

reg.getApplicationInfoManager().setInstanceStatus(InstanceInfo.InstanceStatus.DOWN);

这行代码，设置了实例的状态为DOWN，这个时候会触发状态监听器，将实例的最新状态重新注册到Eureka上面去

，这个时候在Eureka上面的状态，该类的状态就是DOWN，通过日志可以很详细的看出来

Eureka Client


2018-06-08 15:14:46.944 [Thread-12] INFO o.s.c.n.e.serviceregistry.EurekaServiceRegistry - Unregistering application gs-job-admin with eureka with status DOWN
2018-06-08 15:14:46.944 [Thread-12] WARN com.netflix.discovery.DiscoveryClient - Saw local status change event StatusChangeEvent [timestamp=1528442086944, current=DOWN, previous=UP]
2018-06-08 15:14:46.945 [DiscoveryClient-InstanceInfoReplicator-0] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200: registering service...
2018-06-08 15:14:46.946 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Shutting down DiscoveryClient ...
2018-06-08 15:14:46.948 [DiscoveryClient-InstanceInfoReplicator-0] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200 - registration status: 204
2018-06-08 15:14:46.948 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Unregistering ...
2018-06-08 15:14:46.953 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200 - deregister status: 200
2018-06-08 15:14:46.955 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Completed shut down of DiscoveryClient2018-06-08 15:14:46.944 [Thread-12] INFO o.s.c.n.e.serviceregistry.EurekaServiceRegistry - Unregistering application gs-job-admin with eureka with status DOWN
2018-06-08 15:14:46.944 [Thread-12] WARN com.netflix.discovery.DiscoveryClient - Saw local status change event StatusChangeEvent [timestamp=1528442086944, current=DOWN, previous=UP]
2018-06-08 15:14:46.945 [DiscoveryClient-InstanceInfoReplicator-0] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200: registering service...
2018-06-08 15:14:46.946 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Shutting down DiscoveryClient ...
2018-06-08 15:14:46.948 [DiscoveryClient-InstanceInfoReplicator-0] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200 - registration status: 204
2018-06-08 15:14:46.948 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Unregistering ...
2018-06-08 15:14:46.953 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - DiscoveryClient_GS-JOB-ADMIN/10.28.144.127:8200 - deregister status: 200
2018-06-08 15:14:46.955 [Thread-12] INFO com.netflix.discovery.DiscoveryClient - Completed shut down of DiscoveryClient

Eureka Server


2018-06-08 15:14:47.455 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.e.p.b.e.r.listener.InstanceStateChangeListener.listen:108 - instance registered GS-JOB-ADMIN 10.28.144.127:8200 true DOWN, {management.port=18200}
2018-06-08 15:14:47.456 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.netflix.eureka.registry.AbstractInstanceRegistry.register:267 - Registered instance GS-JOB-ADMIN/10.28.144.127:8200 with status DOWN (replication=true)
2018-06-08 15:14:47.457 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.netflix.eureka.registry.AbstractInstanceRegistry.internalCancel:331 - Cancelled instance GS-JOB-ADMIN/10.28.144.127:8200 (replication=true)2018-06-08 15:14:47.455 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.e.p.b.e.r.listener.InstanceStateChangeListener.listen:108 - instance registered GS-JOB-ADMIN 10.28.144.127:8200 true DOWN, {management.port=18200}
2018-06-08 15:14:47.456 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.netflix.eureka.registry.AbstractInstanceRegistry.register:267 - Registered instance GS-JOB-ADMIN/10.28.144.127:8200 with status DOWN (replication=true)
2018-06-08 15:14:47.457 eureka-resitry-ms 10.29.184.48 [http-nio-8081-exec-3] INFO  c.netflix.eureka.registry.AbstractInstanceRegistry.internalCancel:331 - Cancelled instance GS-JOB-ADMIN/10.28.144.127:8200 (replication=true)

状态变更为DOWN 之后， Eureka Client会继续执行unregister()方法，执行下线操作。

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