nacos注册中心之服务注册

nacos注册中心之服务注册

NacosServiceRegistry的register方法：

public void register(Registration registration) {
    if (StringUtils.isEmpty(registration.getServiceId())) {
        log.warn("No service to register for nacos client...");
    } else {
        String serviceId = registration.getServiceId();
        String group = this.nacosDiscoveryProperties.getGroup();
        Instance instance = this.getNacosInstanceFromRegistration(registration);

        try {
            this.namingService.registerInstance(serviceId, group, instance);
            log.info("nacos registry, {} {} {}:{} register finished", new Object[]{group, serviceId, instance.getIp(), instance.getPort()});
        } catch (Exception var6) {
            log.error("nacos registry, {} register failed...{},", new Object[]{serviceId, registration.toString(), var6});
            ReflectionUtils.rethrowRuntimeException(var6);
        }

    }
}

方法中调用Nacos Client 的registerInstance完成服务的注册

registerInstance方法：

@Override
public void registerInstance(String serviceName, String groupName, Instance instance) throws NacosException {

    if (instance.isEphemeral()) {
        BeatInfo beatInfo = new BeatInfo();
        beatInfo.setServiceName(NamingUtils.getGroupedName(serviceName, groupName));
        beatInfo.setIp(instance.getIp());
        beatInfo.setPort(instance.getPort());
        beatInfo.setCluster(instance.getClusterName());
        beatInfo.setWeight(instance.getWeight());
        beatInfo.setMetadata(instance.getMetadata());
        beatInfo.setScheduled(false);
        long instanceInterval = instance.getInstanceHeartBeatInterval();
        beatInfo.setPeriod(instanceInterval == 0 ? DEFAULT_HEART_BEAT_INTERVAL : instanceInterval);

        beatReactor.addBeatInfo(NamingUtils.getGroupedName(serviceName, groupName), beatInfo);
    }

    serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);
}

1. 通过beatReactor.addBeatInfo创建心跳信息实现健康监测，Naocs Server必须确保注册的服务实例是健康的，而心跳检测就是服务健康检测的手段
2. serverProxy.registerService实现服务的注册。

addBeatInfo方法：

public void addBeatInfo(String serviceName, BeatInfo beatInfo) {
    NAMING_LOGGER.info("[BEAT] adding beat: {} to beat map.", beatInfo);
    String key = buildKey(serviceName, beatInfo.getIp(), beatInfo.getPort());
    BeatInfo existBeat = null;
    //fix #1733
    if ((existBeat = dom2Beat.remove(key)) != null) {
        existBeat.setStopped(true);
    }
    dom2Beat.put(key, beatInfo);
    executorService.schedule(new BeatTask(beatInfo), beatInfo.getPeriod(), TimeUnit.MILLISECONDS);
    MetricsMonitor.getDom2BeatSizeMonitor().set(dom2Beat.size());
}

所谓心跳机制就是客户端通过schedule方法定时向服务端发送一个数据包，然后启动一个线程不断检测服务端的回应，如果在设定时间内没有收到服务端的回应，则认为服务器发生故障。Nacos服务端根据客户端的心跳包不断更新服务状态。

接下来就是serverProxy.registerService进行服务的注册，进入方法可以看到其实是一个HTTP协议的POST请求，也就是Nacos提供了Open API来实现服务的注册，SDK进行了封装。