go 协程之WaitGroup超时控制

package main

import (
  "fmt"
  "sync"
  "time"
)

// 调用示例
func main() {
  var w = sync.WaitGroup{}
  var ch = make(chan bool)
  w.Add(2)
  go func() {
    time.Sleep(time.Second * 2)
    fmt.Println("我2秒")
    w.Done()
  }()
  go func() {
    time.Sleep(time.Second * 6)
    fmt.Println("我6秒")
    w.Done()
  }()
  go func() {
    w.Wait()
    ch <- false
  }()

  select {
  case <-time.After(time.Second * 7):
    fmt.Println("我超时了")
  case <-ch:
    fmt.Println("我结束了")
  }
}