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SpringCloud中NacosNamingService的作用详解

2023-11-15 08:54:23 作者：阿孟呀

这篇文章主要介绍了SpringCloud中NacosNamingService的作用详解,NacosNamingService类完成服务实例注册,撤销与获取服务实例操作,NacosNamingService初始化采用单例模式,使用反射生成,需要的朋友可以参考下

NacosNamingService初始化

NacosNamingService类完成服务实例注册，撤销与获取服务实例操作。

生成方式:NacosNamingService初始化采用单例模式，使用反射生成。

NacosServiceRegistry bean初始化时，在构造中，根据nacos的属性配置文件,通过反射，初始化了NacosNamingService。

NacosServiceRegistry

public NacosServiceRegistry(NacosDiscoveryProperties nacosDiscoveryProperties) {
		this.nacosDiscoveryProperties = nacosDiscoveryProperties;
		this.namingService = nacosDiscoveryProperties.namingServiceInstance();
	}

NacosDiscoveryProperties

public NamingService namingServiceInstance() {
 
		if (null != namingService) {
			return namingService;
		}
 
		try {
			namingService = NacosFactory.createNamingService(getNacosProperties());
		}
		catch (Exception e) {
			log.error("create naming service error!properties={},e=,", this, e);
			return null;
		}
		return namingService;
	}

NamingFactory

public static NamingService createNamingService(Properties properties) throws NacosException {
        try {
            Class<?> driverImplClass = Class.forName("com.alibaba.nacos.client.naming.NacosNamingService");
            Constructor constructor = driverImplClass.getConstructor(Properties.class);
            NamingService vendorImpl = (NamingService)constructor.newInstance(properties);
            return vendorImpl;
        } catch (Throwable e) {
            throw new NacosException(NacosException.CLIENT_INVALID_PARAM, e);
        }
    }

NacosNamingService初始化过程

NacosNamingService初始化时，主要是进行了以下操作:

初始化命名空间，默认为public
初始化服务端地址.xxx:8848
初始化naocs 服务端两个webcontext，"/nacos//v1/ns"和"/nacos//v1/ns//instance"
初始化服务实例信息缓存目录，默认为用户目录下"/nacos/naming/public"
初始化日志
初始化事件分发器
初始化NamingProxy，像服务端发起请求的代理
初始化心跳信息，使用ScheduledThreadPoolExecutor初始化守护线程池，nacos默认5秒像服务端发起一次心跳，
初始化主机信息，默认不使用本地缓存。

public NacosNamingService(Properties properties) {
        init(properties);
    }
 
    private void init(Properties properties) {
        namespace = InitUtils.initNamespaceForNaming(properties);
        initServerAddr(properties);
        InitUtils.initWebRootContext();
        initCacheDir();
        initLogName(properties);
 
        eventDispatcher = new EventDispatcher();
        serverProxy = new NamingProxy(namespace, endpoint, serverList);
        serverProxy.setProperties(properties);
        beatReactor = new BeatReactor(serverProxy, initClientBeatThreadCount(properties));
        hostReactor = new HostReactor(eventDispatcher, serverProxy, cacheDir, isLoadCacheAtStart(properties), initPollingThreadCount(properties));
    }

NacosNamingService心跳启动

客户端向服务端发起请求时，会先通过定时任务启动心跳，默认心跳为5秒一次

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);
               //启动心跳任务
            beatReactor.addBeatInfo(NamingUtils.getGroupedName(serviceName, groupName), beatInfo);
        }
 
        serverProxy.registerService(NamingUtils.getGroupedName(serviceName, groupName), groupName, instance);
    }

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);//开启定时心跳任务
        executorService.schedule(new BeatTask(beatInfo), beatInfo.getPeriod(), TimeUnit.MILLISECONDS);
        MetricsMonitor.getDom2BeatSizeMonitor().set(dom2Beat.size());
    }

获取服务实例

@Override
    public List<Instance> getAllInstances(String serviceName, String groupName, List<String> clusters, boolean subscribe) throws NacosException {
 
        ServiceInfo serviceInfo;
        if (subscribe) {
            serviceInfo = hostReactor.getServiceInfo(NamingUtils.getGroupedName(serviceName, groupName), StringUtils.join(clusters, ","));//本地map获取
        } else {
            serviceInfo = hostReactor.getServiceInfoDirectlyFromServer(NamingUtils.getGroupedName(serviceName, groupName), StringUtils.join(clusters, ","));//远程服务获取
        }
        List<Instance> list;
        if (serviceInfo == null || CollectionUtils.isEmpty(list = serviceInfo.getHosts())) {
            return new ArrayList<Instance>();
        }
        return list;
    }

服务实例注销

@Override
    public void deregisterInstance(String serviceName, String groupName, Instance instance) throws NacosException {
        if (instance.isEphemeral()) {
            beatReactor.removeBeatInfo(NamingUtils.getGroupedName(serviceName, groupName), instance.getIp(), instance.getPort());
        }
        serverProxy.deregisterService(NamingUtils.getGroupedName(serviceName, groupName), instance);
    }

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