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关于nacos:Nacos-服务端处理注册请求

jiezi

Nacos – 客户端注册曾经讲过了，那这里讲一下服务端是怎么解决申请的。
解决客户的申请在 InstanceController 里，咱们看看 register 办法。

InstanceController#register

这里次要是封装 Instance，并调用 serviceManager 的 registerInstance 办法进行服务注册。

public String register(HttpServletRequest request) throws Exception {
    // 获取 namespaceId
    final String namespaceId = WebUtils
            .optional(request, CommonParams.NAMESPACE_ID, Constants.DEFAULT_NAMESPACE_ID);
    // 获取 serviceName
    final String serviceName = WebUtils.required(request, CommonParams.SERVICE_NAME);
    // 验证 serviceName 的合法性
    NamingUtils.checkServiceNameFormat(serviceName);
    // 封装并验证 Instance 的合法性
    final Instance instance = parseInstance(request);
    // 服务注册
    serviceManager.registerInstance(namespaceId, serviceName, instance);
    return "ok";
}

ServiceManager#registerInstance

判断是否曾经注册过，如果没有注册，则创立一个 Service 并注册，而后再增加实例。

public void registerInstance(String namespaceId, String serviceName, Instance instance) throws NacosException {
    // 是否曾经注册过，如果没有注册，则创立一个 Service 并注册
    createEmptyService(namespaceId, serviceName, instance.isEphemeral());
    // 从注册的服务中取 Service
    Service service = getService(namespaceId, serviceName);
    
    if (service == null) {
        throw new NacosException(NacosException.INVALID_PARAM,
                "service not found, namespace:" + namespaceId + ", service:" + serviceName);
    }
    // 增加实例
    addInstance(namespaceId, serviceName, instance.isEphemeral(), instance);
}

ServiceManager#createEmptyService

间接调用 createServiceIfAbsent 办法。

public void createEmptyService(String namespaceId, String serviceName, boolean local) throws NacosException {createServiceIfAbsent(namespaceId, serviceName, local, null);
}

ServiceManager#createServiceIfAbsent

public void createServiceIfAbsent(String namespaceId, String serviceName, boolean local, Cluster cluster)
        throws NacosException {
    // 获取 Service
    Service service = getService(namespaceId, serviceName);
    if (service == null) {
        // 没有获取到则创立
        Loggers.SRV_LOG.info("creating empty service {}:{}", namespaceId, serviceName);
        service = new Service();
        service.setName(serviceName);
        service.setNamespaceId(namespaceId);
        service.setGroupName(NamingUtils.getGroupName(serviceName));
        // now validate the service. if failed, exception will be thrown
        service.setLastModifiedMillis(System.currentTimeMillis());
        // checksum 用于校验的
        service.recalculateChecksum();
        if (cluster != null) {
            // 退出到集群
            cluster.setService(service);
            service.getClusterMap().put(cluster.getName(), cluster);
        }
        // 验证服务和集群名称的合法性
        service.validate();
        // 放入缓存并查看心跳
        putServiceAndInit(service);
        if (!local) {
            // 一致性协定保留
            addOrReplaceService(service);
        }
    }
}

ServiceManager#putServiceAndInit

Service 存入 serviceMap 缓存，并每 5 秒健康检查 

private void putServiceAndInit(Service service) throws NacosException {
    // 存入 serviceMap 缓存
    putService(service);
    // 每 5 秒健康检查，包含 service 和 cluster
    service.init();
    // 增加监听，包含长期和永恒
    consistencyService
            .listen(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), true), service);
    consistencyService
            .listen(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), false), service);
    Loggers.SRV_LOG.info("[NEW-SERVICE] {}", service.toJson());
}

ServiceManager#getService

从 serviceMap 缓存中取值。

public Service getService(String namespaceId, String serviceName) {if (serviceMap.get(namespaceId) == null) {return null;}
    return chooseServiceMap(namespaceId).get(serviceName);
}

public Map<String, Service> chooseServiceMap(String namespaceId) {return serviceMap.get(namespaceId);
}

ServiceManager#addInstance

保留实例 

public void addInstance(String namespaceId, String serviceName, boolean ephemeral, Instance... ips)
        throws NacosException {
    // 获取实例 key
    String key = KeyBuilder.buildInstanceListKey(namespaceId, serviceName, ephemeral);
    // 从缓存 serviceMap 获取 Service
    Service service = getService(namespaceId, serviceName);
    
    synchronized (service) {
        // 获取 service 的所有实例
        List<Instance> instanceList = addIpAddresses(service, ephemeral, ips);
        
        Instances instances = new Instances();
        instances.setInstanceList(instanceList);
        // 一致性保留，理论调用 DistroConsistencyServiceImpl#put
        consistencyService.put(key, instances);
    }
}

ServiceManager#addIpAddresses

间接调用 updateIpAddresses 办法 

private List<Instance> addIpAddresses(Service service, boolean ephemeral, Instance... ips) throws NacosException {return updateIpAddresses(service, UtilsAndCommons.UPDATE_INSTANCE_ACTION_ADD, ephemeral, ips);
}

ServiceManager#updateIpAddresses

获取 service 的所有实例，这里会更新老数据 

public List<Instance> updateIpAddresses(Service service, String action, boolean ephemeral, Instance... ips)
        throws NacosException {
    // 获取旧数据
    Datum datum = consistencyService
            .get(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), ephemeral));
    // 获取集群中所有的实例
    List<Instance> currentIPs = service.allIPs(ephemeral);
    Map<String, Instance> currentInstances = new HashMap<>(currentIPs.size());
    Set<String> currentInstanceIds = Sets.newHashSet();
    // 遍历所有实例，key 为 ip+ 端口
    for (Instance instance : currentIPs) {currentInstances.put(instance.toIpAddr(), instance);
        currentInstanceIds.add(instance.getInstanceId());
    }
    // 定义新数据
    Map<String, Instance> instanceMap;
    if (datum != null && null != datum.value) {
        // 如果有老数据，通过 currentInstances 来更新衰弱状态和心跳工夫
        instanceMap = setValid(((Instances) datum.value).getInstanceList(), currentInstances);
    } else {
        // 没有就创立一个
        instanceMap = new HashMap<>(ips.length);
    }
    
    for (Instance instance : ips) {
        // 不存在，就创立一个 Cluster 集群，并开启健康检查
        if (!service.getClusterMap().containsKey(instance.getClusterName())) {
            // 从新创立一个
            Cluster cluster = new Cluster(instance.getClusterName(), service);
            // 开启健康检查
            cluster.init();
            service.getClusterMap().put(instance.getClusterName(), cluster);
            Loggers.SRV_LOG
                    .warn("cluster: {} not found, ip: {}, will create new cluster with default configuration.",
                            instance.getClusterName(), instance.toJson());
        }
        // 删除操作的话，就删除实例
        if (UtilsAndCommons.UPDATE_INSTANCE_ACTION_REMOVE.equals(action)) {instanceMap.remove(instance.getDatumKey());
        } else {
            // 新增实例，设置惟一 id
            instance.setInstanceId(instance.generateInstanceId(currentInstanceIds));
            instanceMap.put(instance.getDatumKey(), instance);
        }
        
    }
    
    if (instanceMap.size() <= 0 && UtilsAndCommons.UPDATE_INSTANCE_ACTION_ADD.equals(action)) {
        throw new IllegalArgumentException("ip list can not be empty, service:" + service.getName() + ", ip list:" + JacksonUtils
                        .toJson(instanceMap.values()));
    }
    // 返回所有实例
    return new ArrayList<>(instanceMap.values());
}

DistroConsistencyServiceImpl#put

如果是长期，则退出缓存，并放入阻塞队列。

public void put(String key, Record value) throws NacosException {onPut(key, value);
    // 一致性服务
    distroProtocol.sync(new DistroKey(key, KeyBuilder.INSTANCE_LIST_KEY_PREFIX), DataOperation.CHANGE,
            globalConfig.getTaskDispatchPeriod() / 2);
}


public void onPut(String key, Record value) {
    // 长期退出 dataStore 缓存
    if (KeyBuilder.matchEphemeralInstanceListKey(key)) {Datum<Instances> datum = new Datum<>();
        datum.value = (Instances) value;
        datum.key = key;
        datum.timestamp.incrementAndGet();
        dataStore.put(key, datum);
    }
    
    if (!listeners.containsKey(key)) {return;}
    // 在 notifier 的阻塞队列退出 ArrayBlockingQueue
    notifier.addTask(key, DataOperation.CHANGE);
}

DistroConsistencyServiceImp.Notifierl#run

调用 handle 办法 

@Override
public void run() {Loggers.DISTRO.info("distro notifier started");
    
    for (; ;) {
        try {Pair<String, DataOperation> pair = tasks.take();
            handle(pair);
        } catch (Throwable e) {Loggers.DISTRO.error("[NACOS-DISTRO] Error while handling notifying task", e);
        }
    }
}

DistroConsistencyServiceImp.Notifierl#handle

对事件进行告诉 

private void handle(Pair<String, DataOperation> pair) {
    try {String datumKey = pair.getValue0();
        DataOperation action = pair.getValue1();
        
        services.remove(datumKey);
        
        int count = 0;
        // 没有监听，返回
        if (!listeners.containsKey(datumKey)) {return;}
        
        for (RecordListener listener : listeners.get(datumKey)) {
            
            count++;
            
            try {if (action == DataOperation.CHANGE) {
                    // 解决变更事件
                    listener.onChange(datumKey, dataStore.get(datumKey).value);
                    continue;
                }
                
                if (action == DataOperation.DELETE) {
                    // 解决删除事件
                    listener.onDelete(datumKey);
                    continue;
                }
            } catch (Throwable e) {Loggers.DISTRO.error("[NACOS-DISTRO] error while notifying listener of key: {}", datumKey, e);
            }
        }
        
        if (Loggers.DISTRO.isDebugEnabled()) {
            Loggers.DISTRO
                    .debug("[NACOS-DISTRO] datum change notified, key: {}, listener count: {}, action: {}",
                            datumKey, count, action.name());
        }
    } catch (Throwable e) {Loggers.DISTRO.error("[NACOS-DISTRO] Error while handling notifying task", e);
    }
}

总结

  1. 服务、集群如果不存在，则创立，并注册监听事件。
  2. 开启服务、集群的健康检查。
  3. 如果有旧服务数据，则更新衰弱状态和心跳工夫。
  4. 节点的数据一致性。
  5. 调用监听。

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