Nodejs：错误的回调订单

时间：2018-05-10 18:39:57

标签： node.js mongodb typescript websocket

我有3个使用网络套接字交换消息的nodejs服务。

第一个服务通过Web套接字将事件发送到第二个服务。第二个服务负责详细说明事件并将它们保存在mongodb数据库上，一旦事件已保存在数据库上，第二个服务就将详细事件发送到第三个服务（gui），始终使用Web套接字。

这是从第一个接收事件的第二个服务的代码：

this.socketClient.on('NEW_EVENT', (event: MyEvent) => {
 winston.info(`[newEvent] New Event received: %s`, event.type);
 console.log('0__', event.payload);

 // Search for the right class that can handle the specific event
 for (const handler of this.handlers) {
   if (handler.isApplicable(event.type)) {
       // Handler found
       handler.handle(event).then((handledEvent) => {
          console.log('1__', handledEvent);  
          // Send the handled event to the gui
          this.webSockerService.publishNewEvent(event.type, handledEvent);
       });
       return;
  }
 }
});

这是Handler的代码，负责处理一个特定事件（在这种情况下，它只是调用正确的服务来处理事件）：

public async handle(event: Event): Promise<Component> {
  winston.info('[ComponentHandler:handle]');
  return this.componentService
               .componentStatusChanged(event.header.sender, event.header.senderType, event.payload);
}

这是我的componentService类的代码（在这个特定的情况下，它只使用负责将数据库中的事件保存的正确的存储库）

public async componentStatusChanged(componentId: string, componentType: ComponentType, componentStatus: ComponentStatus): Promise<any> {
  return this.componentRepository
                   .componentStatusChanged(componentId, componentType, componentStatus);
}

这是我的componentRepository的代码：

public async componentStatusChanged(componentId: string, componentType: ComponentType, componentStatus: ComponentStatus): Promise<Component> {
  winston.info('[ComponentRepository::componentStatusChanged] Component %s newStatus %s', componentId, componentStatus);

  try {
    await this.fetch({ name: componentId });
    return this.update(componentId, { status: componentStatus });
  } catch (ex) {
    // Component not exists
    const newComponent: Component = {
                name: componentId,
                type: componentType,
                status: componentStatus,
                updatedAt: new Date().getTime()
     };
     return this.newComponent(newComponent);
  }
}

public async update(componentId: string, newValues: any): Promise<Component> {
  winston.info('[ComponentRepository::update] Updating component %s. New Values: %j', componentId, newValues);
  await this.component.get().update({ name: componentId }, newValues);
  return this.fetch({ name: componentId });
}

public async newComponent(component: Component): Promise<Component> {
  winston.info('[ComponentRepository::newComponent] Creating Component %j', component);
  return this.component.get().create(component);
}

public async fetch(filter: any): Promise<Component> {
  winston.info('[ComponentRepository::fetch] component %j', filter);
  return this.component.get().findOne(filter);
}

问题是第二个服务以正确的顺序接收事件，但它会在一些日志之后将它们转发给错误的gui：

第二个组件收到的事件有效负载：STARTED - ＆gt;分析 - ＆gt;聆听 - ＆gt;分析 - ＆gt;聆听 - ＆gt;分析 - ＆gt;聆听......

正如您在日志中看到的那样，console.log('0__...)打印的事件的顺序与console.log('1___....)

打印的事件的顺序不同 
info: [newEvent] New Event received: STATUS
0___ STARTED
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus STARTED
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"STARTED"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ ANALYZING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [newEvent] New Event received: STATUS
0___ LISTENING
info: [ComponentHandler:handle]
info: [ComponentRepository::componentStatusChanged] Component auth.srv newStatus LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"ANALYZING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::update] Updating component auth.srv. New Values: {"status":"LISTENING"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'ANALYZING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS ANALYZING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'ANALYZING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'ANALYZING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS ANALYZING
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
info: [ComponentRepository::fetch] component {"name":"auth.srv"}
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING
1____ { _id: 5af470ae8278f6320b3a00f3,
  name: 'auth.srv',
  type: 'AUTH_SERVICE',
  status: 'LISTENING',
  updatedAt: 1525969070608,
  __v: 0 }
info: [WebSocketService::publishNewEvent] type: STATUS LISTENING'

修改

当我使用WebSockets时，似乎有某种竞争条件。我试图单独测试我的组件，没有问题。只要我使用websockets并快速重复发布事件，就会在回调堆栈上发生一些事情。 如何按正确的顺序处理事件？问题似乎是当我尝试在mongodb上进行I / O操作时。 谢谢

1 个答案:

答案 0 :(得分：0)

我解决了创建单独处理的事件队列的问题。

如果您有更好的解决方案，请在此处发布。

constructor() {
 setInterval(async () => {
   if (this.newEvents.length > 0) {
     await this.handleNewEvents();
   }
 }, 50);
}

this.socketClient.on('NEW_EVENT', (event: MyEvent) => {
   this.newEvents.push(event);
});


private async handleNewEvents(): Promise<any> {
  const event = this.newEvents.shift();
  await this.handleEvent(event);
  if (this.newEvents.length > 0) {
     await this.handleNewEvents();
  }
}

private async handleEvent(event: Event): Promise<any> {
   return new Promise((resolve, reject) => {
       for (const handler of this.handlers) {
           if (handler.isApplicable(event.type)) {
                handler.handle(event).then((handledEvent) => {
                  this.webSockerService.publishNewEvent(event.type, handledEvent);
                      resolve();
                  });
                  return;
               }
            }
        winston.error('Handler not found for %s ', event.type);
           reject();
        });
    }
}
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