【Eureka】【源码+图解】【六】Eureka的续约功能

目录

• 6. 下线
• • 6.1 shutdown()
  • 6.2 服务端cancel
  • 6.3 同步其他server节点

6. 下线

主动下线方式

服务端：/eureka/apps/{application.name}/{instance-id}，以本系列文章的helloworld为例，发送DELETE请求http://localhost:3333/eureka/apps/MY-EUREKA-CLIENT/localhost:my-eureka-client:2222便可将客户端实例下线

客户端：

1、创建Controller

@RestController
public class EurekaController {@GetMapping("/cancel")public void cancel() {DiscoveryManager.getInstance().shutdownComponent();}
}

2、浏览器直接拍http://localhost:2222/cancel即可将客户端实例下线

下线的整体流程图

主要分析绿色的三个步骤

6.1 shutdown()

public class DiscoveryClient implements EurekaClient {@PreDestroy@Overridepublic synchronized void shutdown() {if (isShutdown.compareAndSet(false, true)) {......// 注销监听器if (statusChangeListener != null && applicationInfoManager != null) {applicationInfoManager.unregisterStatusChangeListener(statusChangeListener.getId());}// 取消定时任务，包括注册、续约、更新注册信息等cancelScheduledTasks();// 注销if (applicationInfoManager != null&& clientConfig.shouldRegisterWithEureka()&& clientConfig.shouldUnregisterOnShutdown()) {applicationInfoManager.setInstanceStatus(InstanceStatus.DOWN);unregister(); // 向服务端发送下线请求}if (eurekaTransport != null) {// 关闭eurekaTransporteurekaTransport.shutdown();}......}}
}

6.2 服务端cancel

public abstract class AbstractInstanceRegistry implements InstanceRegistry {@Overridepublic boolean cancel(String appName, String id, boolean isReplication) {// 1、从内存实例注册表registry删除// 2、添加到recentCanceledQueue// 3、从overriddenInstanceStatusMap删除// 4、添加到recentlyChangedQueue// 5、从缓存responseCache中删除return internalCancel(appName, id, isReplication);}
}

6.3 同步其他server节点

public class PeerAwareInstanceRegistryImpl extends AbstractInstanceRegistry implements PeerAwareInstanceRegistry {@Overridepublic boolean cancel(final String appName, final String id,final boolean isReplication) {if (super.cancel(appName, id, isReplication)) {// 除了Action.Cancel与register不同，其他可参考register章节replicateToPeers(Action.Cancel, appName, id, null, null, isReplication);return true;}return false;}
}

未完待续