Nacos服务注册客户端服务端原理分析

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <version>${latest.version}</version>
</dependency>

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.alibaba.cloud.nacos.NacosDiscoveryAutoConfiguration,\
  com.alibaba.cloud.nacos.ribbon.RibbonNacosAutoConfiguration,\
  com.alibaba.cloud.nacos.endpoint.NacosDiscoveryEndpointAutoConfiguration,\
  com.alibaba.cloud.nacos.discovery.NacosDiscoveryClientAutoConfiguration,\
  com.alibaba.cloud.nacos.discovery.configclient.NacosConfigServerAutoConfiguration
org.springframework.cloud.bootstrap.BootstrapConfiguration=\
  com.alibaba.cloud.nacos.discovery.configclient.NacosDiscoveryClientConfigServiceBootstrapConfiguration

public void onApplicationEvent(WebServerInitializedEvent event) {
  bind(event);
}

public void bind(WebServerInitializedEvent event) {
		ApplicationContext context = event.getApplicationContext();
		if (context instanceof ConfigurableWebServerApplicationContext) {
			if ("management".equals(((ConfigurableWebServerApplicationContext) context)
					.getServerNamespace())) {
				return;
			}
		}
		this.port.compareAndSet(0, event.getWebServer().getPort());
    // 调用 start 方法
		this.start();
	}

public void start() {
  if (!isEnabled()) {
    if (logger.isDebugEnabled()) {
      logger.debug("Discovery Lifecycle disabled. Not starting");
    }
    return;
  }
  if (!this.running.get()) {
    this.context.publishEvent(
        new InstancePreRegisteredEvent(this, getRegistration()));
    register();
    if (shouldRegisterManagement()) {
      registerManagement();
    }
    this.context.publishEvent(
        new InstanceRegisteredEvent<>(this, getConfiguration()));
    this.running.compareAndSet(false, true);
  }
}

public void register(Registration registration) {
  if (StringUtils.isEmpty(registration.getServiceId())) {
    log.warn("No service to register for nacos client...");
    return;
  }
  String serviceId = registration.getServiceId();
  String group = nacosDiscoveryProperties.getGroup();
  // 创建实例
  Instance instance = getNacosInstanceFromRegistration(registration);
  try {
    // 注册实例 
    namingService.registerInstance(serviceId, group, instance);
    log.info("nacos registry, {} {} {}:{} register finished", group, serviceId,
        instance.getIp(), instance.getPort());
  }
  catch (Exception e) {
    log.error("nacos registry, {} register failed...{},", serviceId,
        registration.toString(), e);
  }
}

@Override
public void registerInstance(String serviceName, String groupName, Instance instance) throws NacosException {
    if (instance.isEphemeral()) {
        // 封装心跳包
        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);
        // 发送心跳包
        beatReactor.addBeatInfo(NamingUtils.getGroupedName(serviceName, groupName), beatInfo);
    }
    // 发送实例 
    serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);
}

@PutMapping("/beat")
@Secured(action = ActionTypes.WRITE)
public ObjectNode beat(HttpServletRequest request) throws Exception {
    ObjectNode result = JacksonUtils.createEmptyJsonNode();
    result.put(SwitchEntry.CLIENT_BEAT_INTERVAL, switchDomain.getClientBeatInterval());
    String beat = WebUtils.optional(request, "beat", StringUtils.EMPTY);
    RsInfo clientBeat = null;
    // 判断是否有心跳，存在心跳就转成RsInfo
    if (StringUtils.isNotBlank(beat)) {
        clientBeat = JacksonUtils.toObj(beat, RsInfo.class);
    }
    String clusterName = WebUtils
            .optional(request, CommonParams.CLUSTER_NAME, UtilsAndCommons.DEFAULT_CLUSTER_NAME);
    String ip = WebUtils.optional(request, "ip", StringUtils.EMPTY);
    int port = Integer.parseInt(WebUtils.optional(request, "port", "0"));
    if (clientBeat != null) {
        if (StringUtils.isNotBlank(clientBeat.getCluster())) {
            clusterName = clientBeat.getCluster();
        } else {
            // fix #2533
            clientBeat.setCluster(clusterName);
        }
        ip = clientBeat.getIp();
        port = clientBeat.getPort();
    }
    String namespaceId = WebUtils.optional(request, CommonParams.NAMESPACE_ID, Constants.DEFAULT_NAMESPACE_ID);
    String serviceName = WebUtils.required(request, CommonParams.SERVICE_NAME);
    NamingUtils.checkServiceNameFormat(serviceName);
    Loggers.SRV_LOG.debug("[CLIENT-BEAT] full arguments: beat: {}, serviceName: {}, namespaceId: {}", clientBeat,
            serviceName, namespaceId);
    // 获取实例信息
    BeatInfoInstanceBuilder builder = BeatInfoInstanceBuilder.newBuilder();
    builder.setRequest(request);
    int resultCode = getInstanceOperator()
            .handleBeat(namespaceId, serviceName, ip, port, clusterName, clientBeat, builder);
    result.put(CommonParams.CODE, resultCode);
    // 下次发送心跳包间隔
    result.put(SwitchEntry.CLIENT_BEAT_INTERVAL,
            getInstanceOperator().getHeartBeatInterval(namespaceId, serviceName, ip, port, clusterName));
    result.put(SwitchEntry.LIGHT_BEAT_ENABLED, switchDomain.isLightBeatEnabled());
    return result;
}

private final Map<String, Map<String, Service>> serviceMap = new ConcurrentHashMap<>();

public void onPut(String key, Record value) {
    if (KeyBuilder.matchEphemeralInstanceListKey(key)) {
        Datum<Instances> datum = new Datum<>();
        datum.value = (Instances) value;
        datum.key = key;
        datum.timestamp.incrementAndGet();
         // 数据持久化到缓存中
        dataStore.put(key, datum);
    }
    if (!listeners.containsKey(key)) {
        return;
    }
    notifier.addTask(key, DataOperation.CHANGE);
}