微服务笔记之Eureka03(服务注册分析)

服务注册接口源码分析：

com.netflix.eureka.resources.ApplicationResource#addInstance

public Response addInstance(InstanceInfo info,

                                @HeaderParam(PeerEurekaNode.HEADER_REPLICATION) String isReplication) {

	//注册

        registry.register(info, "true".equals(isReplication));

        return Response.status(204).build();  // 204 to be backwards compatible

}

com.netflix.eureka.registry.PeerAwareInstanceRegistryImpl#register

public void register(final InstanceInfo info, final boolean isReplication) {

	// 心跳检测周期默认90s

        int leaseDuration = Lease.DEFAULT_DURATION_IN_SECS;

    	// 配置文件设置该时间，就用配置文件的设置时间

	if (info.getLeaseInfo() != null && info.getLeaseInfo().getDurationInSecs() > 0) {

            leaseDuration = info.getLeaseInfo().getDurationInSecs();

        }

	// 调用父方法

        super.register(info, leaseDuration, isReplication);

    	// 复制到集群其他节点

	replicateToPeers(Action.Register, info.getAppName(), info.getId(), info, null, isReplication);

}

com.netflix.eureka.registry.AbstractInstanceRegistry#register

public void register(InstanceInfo registrant, int leaseDuration, boolean isReplication) {

        try {

            read.lock();

	    // 从注册表中获取实例信息

            Map<String, Lease<InstanceInfo>> gMap = registry.get(registrant.getAppName());

            REGISTER.increment(isReplication);

	    // 第一次注册时，gMap是null

            if (gMap == null) {

		// 定义一个Map

                final ConcurrentHashMap<String, Lease<InstanceInfo>> gNewMap = new ConcurrentHashMap<String, Lease<InstanceInfo>>();

		// 进行put操作

                gMap = registry.putIfAbsent(registrant.getAppName(), gNewMap);

                if (gMap == null) {

                    gMap = gNewMap;

                }

            }

	    // 根据实例ID获取注册信息，第一次注册获取为空

            Lease<InstanceInfo> existingLease = gMap.get(registrant.getId());

            // 不为空，说明已注册但实例信息发生变化

            if (existingLease != null && (existingLease.getHolder() != null)) {

                Long existingLastDirtyTimestamp = existingLease.getHolder().getLastDirtyTimestamp();

                Long registrationLastDirtyTimestamp = registrant.getLastDirtyTimestamp();

                logger.debug("Existing lease found (existing={}, provided={}", existingLastDirtyTimestamp, registrationLastDirtyTimestamp);

                //

                if (existingLastDirtyTimestamp > registrationLastDirtyTimestamp) {

                    logger.warn("There is an existing lease and the existing lease's dirty timestamp {} is greater" +

                            " than the one that is being registered {}", existingLastDirtyTimestamp, registrationLastDirtyTimestamp);

                    logger.warn("Using the existing instanceInfo instead of the new instanceInfo as the registrant");

                    registrant = existingLease.getHolder();

                }

            } else {

                // 该租约不存在，因此它是一个新的注册

                synchronized (lock) {

                    if (this.expectedNumberOfClientsSendingRenews > 0) {

                        // 因为客户机想要注册它，所以要增加发送更新的客户机的数量

                        this.expectedNumberOfClientsSendingRenews = this.expectedNumberOfClientsSendingRenews + 1;

                        updateRenewsPerMinThreshold();

                    }

                }

                logger.debug("No previous lease information found; it is new registration");

            }

            Lease<InstanceInfo> lease = new Lease<InstanceInfo>(registrant, leaseDuration);

            if (existingLease != null) {

                lease.setServiceUpTimestamp(existingLease.getServiceUpTimestamp());

            }

	    // 将实例信息加入map中

            gMap.put(registrant.getId(), lease);

            synchronized (recentRegisteredQueue) {

                recentRegisteredQueue.add(new Pair<Long, String>(

                        System.currentTimeMillis(),

                        registrant.getAppName() + "(" + registrant.getId() + ")"));

            }

            // 更新状态信息

            if (!InstanceStatus.UNKNOWN.equals(registrant.getOverriddenStatus())) {

                logger.debug("Found overridden status {} for instance {}. Checking to see if needs to be add to the "

                                + "overrides", registrant.getOverriddenStatus(), registrant.getId());

                if (!overriddenInstanceStatusMap.containsKey(registrant.getId())) {

                    logger.info("Not found overridden id {} and hence adding it", registrant.getId());

                    overriddenInstanceStatusMap.put(registrant.getId(), registrant.getOverriddenStatus());

                }

            }

            InstanceStatus overriddenStatusFromMap = overriddenInstanceStatusMap.get(registrant.getId());

            if (overriddenStatusFromMap != null) {

                logger.info("Storing overridden status {} from map", overriddenStatusFromMap);

                registrant.setOverriddenStatus(overriddenStatusFromMap);

            }

            InstanceStatus overriddenInstanceStatus = getOverriddenInstanceStatus(registrant, existingLease, isReplication);

            registrant.setStatusWithoutDirty(overriddenInstanceStatus);

            if (InstanceStatus.UP.equals(registrant.getStatus())) {

                lease.serviceUp();

            }

            registrant.setActionType(ActionType.ADDED);

            recentlyChangedQueue.add(new RecentlyChangedItem(lease));

            registrant.setLastUpdatedTimestamp();

            invalidateCache(registrant.getAppName(), registrant.getVIPAddress(), registrant.getSecureVipAddress());

            logger.info("Registered instance {}/{} with status {} (replication={})",

                    registrant.getAppName(), registrant.getId(), registrant.getStatus(), isReplication);

        } finally {

            read.unlock();

        }

    }

com.netflix.eureka.registry.PeerAwareInstanceRegistryImpl#replicateToPeers

将注册信息同步到集群中其他节点

private void replicateToPeers(Action action, String appName, String id,

                                  InstanceInfo info /* optional */,

                                  InstanceStatus newStatus /* optional */, boolean isReplication) {

        Stopwatch tracer = action.getTimer().start();

        try {

            if (isReplication) {

                numberOfReplicationsLastMin.increment();

            }

            // 如果它已经是一个复制，不要再次复制

            if (peerEurekaNodes == Collections.EMPTY_LIST || isReplication) {

                return;

            }

            for (final PeerEurekaNode node : peerEurekaNodes.getPeerEurekaNodes()) {

                // 如果url表示此主机，则不要复制到自己.

                if (peerEurekaNodes.isThisMyUrl(node.getServiceUrl())) {

                    continue;

                }

		// 复制操作

                replicateInstanceActionsToPeers(action, appName, id, info, newStatus, node);

            }

        } finally {

            tracer.stop();

        }

    }

com.netflix.eureka.registry.PeerAwareInstanceRegistryImpl#replicateInstanceActionsToPeers

复制操作

private void replicateInstanceActionsToPeers(Action action, String appName,

                                                 String id, InstanceInfo info, InstanceStatus newStatus,

                                                 PeerEurekaNode node) {

        try {

            InstanceInfo infoFromRegistry = null;

            CurrentRequestVersion.set(Version.V2);

            switch (action) {

                case Cancel: // 下线

                    node.cancel(appName, id);

                    break;

                case Heartbeat://心跳

                    InstanceStatus overriddenStatus = overriddenInstanceStatusMap.get(id);

                    infoFromRegistry = getInstanceByAppAndId(appName, id, false);

                    node.heartbeat(appName, id, infoFromRegistry, overriddenStatus, false);

                    break;

                case Register://注册

                    node.register(info);

                    break;

                case StatusUpdate:// 状态更新

                    infoFromRegistry = getInstanceByAppAndId(appName, id, false);

                    node.statusUpdate(appName, id, newStatus, infoFromRegistry);

                    break;

                case DeleteStatusOverride:

                    infoFromRegistry = getInstanceByAppAndId(appName, id, false);

                    node.deleteStatusOverride(appName, id, infoFromRegistry);

                    break;

            }

        } catch (Throwable t) {

            logger.error("Cannot replicate information to {} for action {}", node.getServiceUrl(), action.name(), t);

        }

    }

巴特西

微服务笔记之Eureka03(服务注册分析)

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