eureka源码解析——服务续约

eureka源码解析——服务续约

文章目录

• • @[TOC](文章目录)
• 前言
• 一、续约源码解析
• • 1.1 InstanceResource#renewLease
  • 1.2 PeerAwareInstanceRegistryImpl#renew
  • • 1.2.1 AbstractInstanceRegistry#renew
    • 1.2.2 PeerAwareInstanceRegistryImpl#replicateToPeers

前言

服务续约使用过心跳来实现了，客户端会开启一个定时任务，定时向eureka server发送续约请求，然后服务端收到续约信息然后更新租约的最后发送时间，在eureka server中也会开启一个定时任务，定时扫描注册表的实例租约信息，然后看最后续约时间距离现在是不是超过了存活时间(90s)，如果超过了，就将这个实例从注册表中剔除

一、续约源码解析

1.1 InstanceResource#renewLease

客户端会发送续约请求，到服务端的处理接口就是renewLease接口,在这个接口中会调用注册表的renew方法来进行续约。

    public Response renewLease(@HeaderParam(PeerEurekaNode.HEADER_REPLICATION) String isReplication,@QueryParam("overriddenstatus") String overriddenStatus,@QueryParam("status") String status,@QueryParam("lastDirtyTimestamp") String lastDirtyTimestamp) {boolean isFromReplicaNode = "true".equals(isReplication);// 重新续约boolean isSuccess = Name(), id, isFromReplicaNode);// Not found in the registry, immediately ask for a registerif (!isSuccess) {logger.warn("Not Found (Renew): {} - {}", Name(), id);return Response.status(Status.NOT_FOUND).build();}// Check if we need to sync based on dirty time stamp, the client// instance might have changed some valueResponse response;if (lastDirtyTimestamp != null && serverConfig.shouldSyncWhenTimestampDiffers()) {response = this.validateDirtyTimestamp(Long.valueOf(lastDirtyTimestamp), isFromReplicaNode);// Store the overridden status since the validation found out the node that replicates winsif (Status() == Response.Status.StatusCode()&& (overriddenStatus != null)&& !(InstanceStatus.UNKNOWN.name().equals(overriddenStatus))&& isFromReplicaNode) {registry.AppName(), id, InstanceStatus.valueOf(overriddenStatus));}} else {response = Response.ok().build();}logger.debug("Found (Renew): {} - {}; reply status={}", Name(), id, Status());return response;}

1.2 PeerAwareInstanceRegistryImpl#renew

1. 调用父类的AbstractInstanceRegistry的renew方法，更新本地注册表实例租约信息
2. 调用replicateToPeers方法将服务续约请求同步给集群的其他节点

    public boolean renew(final String appName, final String id, final boolean isReplication) {if (w(appName, id, isReplication)) {replicateToPeers(Action.Heartbeat, appName, id, null, null, isReplication);return true;}return false;}

1.2.1 AbstractInstanceRegistry#renew

这里就是更新注册表的租约信息，其实就是更新lastUpdateTimestamp

   public boolean renew(String appName, String id, boolean isReplication) {RENEW.increment(isReplication);// 根据 appName 找到对应的实例租约列表Map<String, Lease<InstanceInfo>> gMap = (appName);Lease<InstanceInfo> leaseToRenew = null;if (gMap != null) {// 通过实例id (instanceId 获取对应实例的租约信息)leaseToRenew = (id);}if (leaseToRenew == null) {RENEW_NOT_FOUND.increment(isReplication);logger.warn("DS: Registry: lease doesn't exist, registering resource: {} - {}", appName, id);return false;} else {InstanceInfo instanceInfo = Holder();if (instanceInfo != null) {// ASGName());InstanceStatus overriddenInstanceStatus = OverriddenInstanceStatus(instanceInfo, leaseToRenew, isReplication);if (overriddenInstanceStatus == InstanceStatus.UNKNOWN) {logger.info("Instance status UNKNOWN possibly due to deleted override for instance {}"+ "; re-register required", Id());RENEW_NOT_FOUND.increment(isReplication);return false;}if (!Status().equals(overriddenInstanceStatus)) {logger.info("The instance status {} is different from overridden instance status {} for instance {}. "+ "Hence setting the status to overridden status", Status().name(),overriddenInstanceStatus.name(),Id());instanceInfo.setStatusWithoutDirty(overriddenInstanceStatus);}}// renew 计数，自我保护机制会用到renewsLastMin.increment();// 实例w();return true;}}//Lease#renewpublic void renew() {// 更新 lastUpdateTimestamplastUpdateTimestamp = System.currentTimeMillis() + duration;}

1.2.2 PeerAwareInstanceRegistryImpl#replicateToPeers

这里就是遍历集群所有的其他节点，然后将实例信息同步到其他节点。

    private void replicateToPeers(Action action, String appName, String id,InstanceInfo info /* optional */,InstanceStatus newStatus /* optional */, boolean isReplication) {Stopwatch tracer = Timer().start();try {if (isReplication) {numberOfReplicationsLastMin.increment();}// If it is a replication already, do not replicate again as this will create a poison replicationif (peerEurekaNodes == Collections.EMPTY_LIST || isReplication) {return;}for (final PeerEurekaNode node : PeerEurekaNodes()) {// If the url represents this host, do not replicate to yourself.if (peerEurekaNodes.ServiceUrl())) {continue;}//复制实例信息到其他节点replicateInstanceActionsToPeers(action, appName, id, info, newStatus, node);}} finally {tracer.stop();}}