Nacos4# 服务端响应连接和注册源码分析（一）

瓜农老梁

发布于 2021-07-14 11:09:16

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发布于 2021-07-14 11:09:16

文章被收录于专栏：瓜农老梁瓜农老梁瓜农老梁

引言

上篇文章分析了Nacos服务端启动的逻辑，本文分析启动时加载了哪些Handler，以及处理连接请求和注册请求的逻辑。

一、内容提要

加载RequestHandler

容器启动时加载了13个RequestHandler由他们实际处理各种请求逻辑后面章节再细撸
当然也加载了InstanceRequest->InstanceRequestHandler

服务端响应客户端连接

处理客户端的连接请求由GrpcBiStreamRequestAcceptor#requestBiStream负责
构建和缓存了GrpcConnection对象和Client对象

服务端处理注册请求

处理注册请求的逻辑由InstanceRequestHandler执行
建立起了client与service、instance的关系
发布了三个事件ClientEvent.ClientChangedEvent、ClientOperationEvent.ClientRegisterServiceEvent、MetadataEvent.InstanceMetadataEvent

二、加载RequestHandler

com.alibaba.nacos.core.remote#RequestHandlerRegistry实现了ApplicationListener，在spring启动后回调onApplicationEvent。

@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
  // 注解@1
  Map<String, RequestHandler> beansOfType = event.getApplicationContext().getBeansOfType(RequestHandler.class);
  Collection<RequestHandler> values = beansOfType.values();
  for (RequestHandler requestHandler : values) {

    Class<?> clazz = requestHandler.getClass();
    boolean skip = false;
    while (!clazz.getSuperclass().equals(RequestHandler.class)) {
      if (clazz.getSuperclass().equals(Object.class)) {
        skip = true;
        break;
      }
      clazz = clazz.getSuperclass();
    }
    if (skip) { // 注解@2 
      continue;
    }

    try {
      // 注解@3
      Method method = clazz.getMethod("handle", Request.class, RequestMeta.class);
      if (method.isAnnotationPresent(TpsControl.class) && TpsControlConfig.isTpsControlEnabled()) {
        TpsControl tpsControl = method.getAnnotation(TpsControl.class);
        String pointName = tpsControl.pointName();
        TpsMonitorPoint tpsMonitorPoint = new TpsMonitorPoint(pointName);
        tpsMonitorManager.registerTpsControlPoint(tpsMonitorPoint);
      }
    } catch (Exception e) {
      //ignore.
    }

    // 注解@4
    Class tClass = (Class) ((ParameterizedType) clazz.getGenericSuperclass()).getActualTypeArguments()[0];
    registryHandlers.putIfAbsent(tClass.getSimpleName(), requestHandler);
  }
}

注解@1： 获取RequestHandler的众多实现类

注解@2： 跳过超类RequestHandler

注解@3： 获取需要带有「TpsControl」注解的方法，表示需要对流量Tps控制

注解@4： 将Handler装载到缓存例如：InstanceRequest->InstanceRequestHandler

小结： 在spring启动时转载了众多的RequestHandler，这些Handler是真正的逻辑所在。下面列表时加载的13个RequestHandler

Key	Value	备注
ConfigBatchListenRequest	ConfigChangeBatchListenRequestHandler
ConfigChangeClusterSyncRequest	ConfigChangeClusterSyncRequestHandler
ConfigPublishRequest	ConfigPublishRequestHandler
ConfigQueryRequest	ConfigQueryRequestHandler
ConfigRemoveRequest	ConfigRemoveRequestHandler
HealthCheckRequest	HealthCheckRequestHandler
ServerLoaderInfoRequest	ServerLoaderInfoRequestHandler
ServerReloadRequest	ServerReloaderRequestHandler
DistroDataRequest	DistroDataRequestHandler
InstanceRequest	InstanceRequestHandler
ServiceListRequest	ServiceListRequestHandler
ConfigPublishRequest	ConfigPublishRequestHandler
SubscribeServiceRequest	SubscribeServiceRequestHandler

三、服务端响应客户端连接

client连接server

在前面《Nacos2# 服务注册与发现客户端示例与源码解析（二）》中client会与server建立连接具体方法为connectToServer()。

在分下《Nacos3# 服务注册与发现服务端启动源码解析》时protobuf文件装载了两类grpc请求类型，其中一类为双向流调用方式BiRequestStream#biRequestStream。

客户端发起connectToServer()时正式双向流调用类型：

 public Connection connectToServer(ServerInfo serverInfo) {
   // ... 
    BiRequestStreamGrpc.BiRequestStreamStub biRequestStreamStub = BiRequestStreamGrpc
                        .newStub(newChannelStubTemp.getChannel());
    
 }
private StreamObserver<Payload> bindRequestStream(final BiRequestStreamGrpc.BiRequestStreamStub streamStub,
            final GrpcConnection grpcConn) {
        
        return streamStub.requestBiStream(new StreamObserver<Payload>() {
          
        }
}

那在nacos server端如何响应的呢？

Nacos server响应连接

在分析《Nacos3# 服务注册与发现服务端启动源码解析》服务端grpc启动构建暴露的服务定义信息时添加了requestBiStream

 private void addServices(MutableHandlerRegistry handlerRegistry, ServerInterceptor... serverInterceptor) {
   // ...
   // 服务接口处理类
   final ServerCallHandler<Payload, Payload> biStreamHandler = ServerCalls.asyncBidiStreamingCall(
     (responseObserver) -> grpcBiStreamRequestAcceptor.requestBiStream(responseObserver));
   // ...
    final ServerServiceDefinition serviceDefOfBiStream = ServerServiceDefinition
                .builder(REQUEST_BI_STREAM_SERVICE_NAME).addMethod(biStreamMethod, biStreamHandler).build();    
 }

接下来看其处理连接请求逻辑。坐标GrpcBiStreamRequestAcceptor#requestBiStream

@Override
public StreamObserver<Payload> requestBiStream(StreamObserver<Payload> responseObserver) {

  StreamObserver<Payload> streamObserver = new StreamObserver<Payload>() {
  // 连接标识 eg. connectionId=1623495108814_127.0.0.1_54314
    final String connectionId = CONTEXT_KEY_CONN_ID.get();
  // eg. localPort=9848
    final Integer localPort = CONTEXT_KEY_CONN_LOCAL_PORT.get();
  // eg. remotePort=54314
    final int remotePort = CONTEXT_KEY_CONN_REMOTE_PORT.get();
  // eg. remoteIp=127.0.0.1
    String remoteIp = CONTEXT_KEY_CONN_REMOTE_IP.get();
  // eg. clientIp=192.168.0.110
    String clientIp = "";

    @Override
    public void onNext(Payload payload) {
   // 解析客户端IP
      clientIp = payload.getMetadata().getClientIp();
      traceDetailIfNecessary(payload);

      Object parseObj = null;
      try {
        parseObj = GrpcUtils.parse(payload); // 将二进制转换为对象
      } catch (Throwable throwable) {
        
      }
    
      if (parseObj instanceof ConnectionSetupRequest) {
        ConnectionSetupRequest setUpRequest = (ConnectionSetupRequest) parseObj;
        Map<String, String> labels = setUpRequest.getLabels();
        String appName = "-";
        if (labels != null && labels.containsKey(Constants.APPNAME)) {
          appName = labels.get(Constants.APPNAME);
        }

       ConnectionMeta metaInfo = new ConnectionMeta(connectionId, payload.getMetadata().getClientIp(),
           remoteIp, remotePort, localPort,ConnectionType.GRPC.getType(),setUpRequest.getClientVersion(), appName, setUpRequest.getLabels());
        metaInfo.setTenant(setUpRequest.getTenant());
        // 注解@5
        Connection connection = new GrpcConnection(metaInfo, responseObserver, CONTEXT_KEY_CHANNEL.get());
        connection.setAbilities(setUpRequest.getAbilities());
        boolean rejectSdkOnStarting = metaInfo.isSdkSource() && !ApplicationUtils.isStarted();
    // 注解@6
        if (rejectSdkOnStarting || !connectionManager.register(connectionId, connection)) {
          try {
           
            connection.request(new ConnectResetRequest(), 3000L);
            connection.close();
          } catch (Exception e) {
            //Do nothing.
            if (connectionManager.traced(clientIp)) {
             
            }
          }
          return;
        }

      } else if (parseObj != null && parseObj instanceof Response) {
        Response response = (Response) parseObj;
        if (connectionManager.traced(clientIp)) {
         
        }
        RpcAckCallbackSynchronizer.ackNotify(connectionId, response);
        connectionManager.refreshActiveTime(connectionId);
      } else {
      
        return;
      }

    }

 
  return streamObserver;
}

注解@5 构建连接对象

注解@6 注册连接信息，一个是缓存连接信息到Map connections中；另一个是触发client连接通知

public synchronized boolean register(String connectionId, Connection connection) {

  if (connection.isConnected()) {
    
    connections.put(connectionId, connection);
    connectionForClientIp.get(connection.getMetaInfo().clientIp).getAndIncrement();

    clientConnectionEventListenerRegistry.notifyClientConnected(connection);
   
    return true;

  }
  return false;

}

client连接通知处理逻辑：坐标ConnectionBasedClientManager#clientConnected。主要构建Client对象并缓存，clientId=connectId

public void clientConnected(Connection connect) {
  if (!RemoteConstants.LABEL_MODULE_NAMING.equals(connect.getMetaInfo().getLabel(RemoteConstants.LABEL_MODULE))) {
    return;
  }
  String type = connect.getMetaInfo().getConnectType();
  ClientFactory clientFactory = ClientFactoryHolder.getInstance().findClientFactory(type);
  // 构建Client对象
  clientConnected(clientFactory.newClient(connect.getMetaInfo().getConnectionId()));
}

 public boolean clientConnected(Client client) {
     Loggers.SRV_LOG.info("Client connection {} connect", client.getClientId());
     if (!clients.containsKey(client.getClientId())) {
       // 缓存Client信息
       clients.putIfAbsent(client.getClientId(), (ConnectionBasedClient) client);
     }
     return true;
 }

小结： Nacos Server响应客户端连接主要干了两件事：@1 构建和缓存GrpcConnection对象，包含ConnectionMeta、channel和StreamObserver；@2 构建和缓存Client对象包含；clientId即connectionId。

ConnectionMeta属性

属性	含义
connectType	ConnectionType，例如：GRPC
clientIp	客户端IP，例如：clientIp=192.168.0.110
remoteIp	远程节点IP，例如：remoteIp=127.0.0.1
remotePort	远程节点端口，例如：remotePort=54314
localPort	本地节点端口，例如：localPort=9848
version	client 版本
connectionId	连接标识
createTime	连接创建时间
lastActiveTime	最新保活时间
appName	app名称默认为“-”
tenant	租户

ConnectionBasedClient属性

属性	含义
connectionId	连接标识
isNative	true表示client直接连接到该server；false表示该连接是被从其他server同步而来
lastRenewTime	当isNative为false时，上次从源server校验的时间戳
lastUpdatedTime	最新保鲜时间

四、服务端处理注册请求

在上面文章《服务注册与发现服务端启动源码解析》有提到由RequestAcceptor.request会处理

// 服务接口处理类
final ServerCallHandler<Payload, Payload> payloadHandler = ServerCalls
  .asyncUnaryCall((request, responseObserver) -> {
    grpcCommonRequestAcceptor.request(request, responseObserver);
  });

下面看下request处理逻辑，忽略一些校验

@Override
public void request(Payload grpcRequest, StreamObserver<Payload> responseObserver) {
  // 查看是否在监控列表
  traceIfNecessary(grpcRequest, true);
  String type = grpcRequest.getMetadata().getType();

  // server启动校验、server校验
  // ...
  // 注解@7
  RequestHandler requestHandler = requestHandlerRegistry.getByRequestType(type);
  // 没有Handler校验
  // ...
  
  String connectionId = CONTEXT_KEY_CONN_ID.get();
  boolean requestValid = connectionManager.checkValid(connectionId);
  // 校验connId是否有效无效返回
  // ...
  Object parseObj = null;
  try {
    parseObj = GrpcUtils.parse(grpcRequest); // 注解@8
  } catch (Exception e) {
    // ...
    return;
  }
  // 非null校验
  if (parseObj == null) {
    // ...
  }
  // 非request校验
  if (!(parseObj instanceof Request)) {
    // ...
    return;
  }
  Request request = (Request) parseObj;
  try {
    Connection connection = connectionManager.getConnection(CONTEXT_KEY_CONN_ID.get());
    RequestMeta requestMeta = new RequestMeta();
    // 注解@9
    requestMeta.setClientIp(connection.getMetaInfo().getClientIp());
    requestMeta.setConnectionId(CONTEXT_KEY_CONN_ID.get());
    requestMeta.setClientVersion(connection.getMetaInfo().getVersion());
    requestMeta.setLabels(connection.getMetaInfo().getLabels());
    // 注解@10
    connectionManager.refreshActiveTime(requestMeta.getConnectionId());
    // 注解@11
    Response response = requestHandler.handleRequest(request, requestMeta);
    Payload payloadResponse = GrpcUtils.convert(response);
    traceIfNecessary(payloadResponse, false);
    responseObserver.onNext(payloadResponse);
    responseObserver.onCompleted();
  } catch (Throwable e) {
    // ...
    return;
  }

}

注解@7 根据请求类型获取处理的RequestHandler，处理注册的为InstanceRequest->InstanceRequestHandler

注解@8 解析成Request对象

注解@9 装载clientIP、connId、version、其他map信息

注解@10 刷新连接保鲜时间

注解@11 执行RequestHandler逻辑，具体为registerInstance

@Override
@Secured(action = ActionTypes.WRITE, parser = NamingResourceParser.class)
public InstanceResponse handle(InstanceRequest request, RequestMeta meta) throws NacosException {
  // 构建注册service
  Service service = Service
    .newService(request.getNamespace(), request.getGroupName(), request.getServiceName(), true);
  switch (request.getType()) {
      // 处理注册请求
    case NamingRemoteConstants.REGISTER_INSTANCE:
      return registerInstance(service, request, meta);
      // 处理注销请求
    case NamingRemoteConstants.DE_REGISTER_INSTANCE:
      return deregisterInstance(service, request, meta);
    default:
      throw new NacosException(NacosException.INVALID_PARAM,
                               String.format("Unsupported request type %s", request.getType()));
  }
}

接着分析注册干了点啥？坐标：EphemeralClientOperationServiceImpl#registerInstance

@Override
public void registerInstance(Service service, Instance instance, String clientId) {
  // 注解@12
  Service singleton = ServiceManager.getInstance().getSingleton(service);
  // 注解@13
  Client client = clientManager.getClient(clientId);
  InstancePublishInfo instanceInfo = getPublishInfo(instance);
  // 注解@14
  client.addServiceInstance(singleton, instanceInfo);
  client.setLastUpdatedTime();
  // 注解@15
  NotifyCenter.publishEvent(new ClientOperationEvent.ClientRegisterServiceEvent(singleton, clientId));
  // 注解@16
  NotifyCenter
    .publishEvent(new MetadataEvent.InstanceMetadataEvent(singleton, instanceInfo.getMetadataId(), false));
}

注解@12 singletonRepository缓存Singleton（service），namespaceSingletonMaps建立namespace和Singleton关系

注解@13 从缓存中获取client信息，也就是上一小节建立连接被缓存的client

注解@14 建立client与service、instance关系并发布事件ClientEvent.ClientChangedEvent

public boolean addServiceInstance(Service service, InstancePublishInfo instancePublishInfo) {
  if (null == publishers.put(service, instancePublishInfo)) {
    MetricsMonitor.incrementInstanceCount();
  }
  NotifyCenter.publishEvent(new ClientEvent.ClientChangedEvent(this));
  Loggers.SRV_LOG.info("Client change for service {}, {}", service, getClientId());
  return true;
}

注解@15 发布ClientOperationEvent.ClientRegisterServiceEvent事件

注解@16 发布MetadataEvent.InstanceMetadataEvent事件

小结： 处理注册请求的逻辑由InstanceRequestHandler执行，建立起了client与service、instance的关系。并通过NotifyCenter发布了三个事件：@1 ClientEvent.ClientChangedEvent；@2 ClientOperationEvent.ClientRegisterServiceEvent事件；@3 MetadataEvent.InstanceMetadataEvent事件。

那谁订阅了这些事件呢？他们又做了啥？下回接着撸。

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原始发表：2021-06-14，如有侵权请联系 cloudcommunity@tencent.com 删除

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