Golang实现观察者模式异步通知方法

type Event struct {

  Data interface{}

}

type Observer interface {

  Update(event Event)

}

type Subject struct {

  observers []Observer

}

func (s *Subject) Register(o Observer) {

  s.observers = append(s.observers, o)

}

func (s *Subject) Notify(event Event) {

  for _, observer := range s.observers {

    go observer.Update(event) // 异步执行

  }

}

type EmailService struct{}

func (e *EmailService) Update(event Event) {

  // 模拟耗时操作

  time.Sleep(100 * time.Millisecond)

  fmt.Printf("邮件服务收到事件: %v\n", event.Data)

}

type LogService struct{}

func (l *LogService) Update(event Event) {

  fmt.Printf("日志服务记录事件: %v\n", event.Data)

}

func (s *Subject) NotifyWithLimit(event Event, maxGoroutines int) {

  sem := make(chan struct{}, maxGoroutines)

  for _, observer := range s.observers {

    sem

    go func(o Observer) {

      defer func() { <-sem }()

      o.Update(event)

    }(observer)

  }

  // 等待所有任务释放信号量（可选：用WaitGroup更精确）

  for i := 0; i < cap(sem); i++ {

    sem

  }

}

func main() {

  subject := &Subject{}

  subject.Register(&EmailService{})

  subject.Register(&LogService{})

  subject.Notify(Event{Data: "用户注册成功"})

  time.Sleep(time.Second) // 等待异步执行完成

}