EurekaClient服务下线源码解析
EurekaClient服务下线整体流程图
1、客户端下线源码解析
1.1 shutdown()
/**
* 1、关闭 EurekaClient，也会发送一个注销的请求到 eureka server
* Shuts down Eureka Client. Also sends a deregistration request to the
* eureka server.
*/
@PreDestroy
@Override
public synchronized void shutdown() {
if (isShutdown.compareAndSet(false, true)) {
logger.info("Shutting down DiscoveryClient ...");
// 1、移除 applicaion 状态改变的监听器(这个监听器在 new DiscoveryClient 的时候添加的)
if (statusChangeListener != null && applicationInfoManager != null) {
applicationInfoManager.unregisterStatusChangeListener(statusChangeListener.getId());
}
// 2、取消定时任务
cancelScheduledTasks();
// 3、这里就是向 eureka server 发送的注销的请求
// If APPINFO was registered
if (applicationInfoManager != null && clientConfig.shouldRegisterWithEureka()) {
// 3.1 设置应用管理的状态为 DOWN
applicationInfoManager.setInstanceStatus(InstanceStatus.DOWN);
// 3.3 发送注销的网络请求
unregister();
}
// 4、关闭网络组件
if (eurekaTransport != null) {
eurekaTransport.shutdown();
}
// 5、监控服务关闭
heartbeatStalenessMonitor.shutdown();
registryStalenessMonitor.shutdown();
logger.info("Completed shut down of DiscoveryClient");
}
}
1.2 unregister(向eureka server 发送的注销请求)
/**
* unregister w/ the eureka service.
*/
void unregister() {
// It can be null if shouldRegisterWithEureka == false
if(eurekaTransport != null && eurekaTransport.registrationClient != null) {
try {
logger.info("Unregistering ...");
// 调用的是 cancel 方法
EurekaHttpResponse<Void> httpResponse = eurekaTransport.registrationClient.cancel(instanceInfo.getAppName(), instanceInfo.getId());
logger.info(PREFIX + appPathIdentifier + " - deregister status: " + httpResponse.getStatusCode());
} catch (Exception e) {
logger.error(PREFIX + appPathIdentifier + " - de-registration failed" + e.getMessage(), e);
}
}
}
2、EurekaServer接收下线请求源码解析
2.1 cancelLease(InstanceResource 的 cancelLease 方法)
@DELETE
public Response cancelLease(
@HeaderParam(PeerEurekaNode.HEADER_REPLICATION) String isReplication) {
boolean isSuccess = registry.cancel(app.getName(), id,
"true".equals(isReplication));
if (isSuccess) {
logger.debug("Found (Cancel): " + app.getName() + " - " + id);
return Response.ok().build();
} else {
logger.info("Not Found (Cancel): " + app.getName() + " - " + id);
return Response.status(Status.NOT_FOUND).build();
}
}
2.2 cancel(PeerAwareInstanceRegistryImpl 的 cancel 方法)
@Override
public boolean cancel(final String appName, final String id,
final boolean isReplication) {
// 1、调用 AbstractInstanceRegistry 的 cancel 方法
if (super.cancel(appName, id, isReplication)) {
// 1.1 复制操作到其他的 eureka server 节点
replicateToPeers(Action.Cancel, appName, id, null, null, isReplication);
// 1.2 上锁
synchronized (lock) {
// 1.3 更新实例的期望心跳数 -2，然后阈值为期望心跳数 * 0.85
if (this.expectedNumberOfRenewsPerMin > 0) {
// Since the client wants to cancel it, reduce the threshold (1 for 30 seconds, 2 for a minute)
this.expectedNumberOfRenewsPerMin = this.expectedNumberOfRenewsPerMin - 2;
this.numberOfRenewsPerMinThreshold =
(int) (this.expectedNumberOfRenewsPerMin * serverConfig.getRenewalPercentThreshold());
}
}
return true;
}
return false;
}
2.3 cancel(AbstractInstanceRegistry.cancel)
protected boolean internalCancel(String appName, String id, boolean isReplication) {
try {
read.lock();
// 1、取消的统计 +1
CANCEL.increment(isReplication);
// 2、注册表中获取 appName 为 key 的 map
Map<String, Lease<InstanceInfo>> gMap = registry.get(appName);
// 3、从 map 中移除 leaseInfo
Lease<InstanceInfo> leaseToCancel = null;
if (gMap != null) {
leaseToCancel = gMap.remove(id);
}
// 4、最近取消的 Queue 添加该实例
synchronized (recentCanceledQueue) {
recentCanceledQueue.add(new Pair<Long, String>(System.currentTimeMillis(), appName + "(" + id + ")"));
}
// 5、overriddenInstanceStatusMap中移除该 id 对应的InstanceStatus信息
InstanceStatus instanceStatus = overriddenInstanceStatusMap.remove(id);
if (instanceStatus != null) {
logger.debug("Removed instance id {} from the overridden map which has value {}", id, instanceStatus.name());
}
// 6、lease 为空，直接返回 false. CANCEL_NOT_FOUND + 1
if (leaseToCancel == null) {
CANCEL_NOT_FOUND.increment(isReplication);
logger.warn("DS: Registry: cancel failed because Lease is not registered for: {}/{}", appName, id);
return false;
} else {
// 7、 lease 取消
leaseToCancel.cancel();
// 8、更新 InstanceInfo 信息
/**
* 1、ActionType 为 DELETED
* 2、RecentlyChangedQueue 添加该实例
* 3、LastUpdatedTimestamp 更新
*/
InstanceInfo instanceInfo = leaseToCancel.getHolder();
String vip = null;
String svip = null;
if (instanceInfo != null) {
instanceInfo.setActionType(ActionType.DELETED);
recentlyChangedQueue.add(new RecentlyChangedItem(leaseToCancel));
instanceInfo.setLastUpdatedTimestamp();
vip = instanceInfo.getVIPAddress();
svip = instanceInfo.getSecureVipAddress();
}
// 9、失效缓存信息
invalidateCache(appName, vip, svip);
logger.info("Cancelled instance {}/{} (replication={})", appName, id, isReplication);
return true;
}
} finally {
read.unlock();
}
}
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