GO 语言超时实现

package main
import (
	"fmt"
	"log"
	"runtime"
	"sync"
	"aaaaa/script/WeatherCDN/tqt"
	"time"
)
var pushFileName = make(chan string)
var wg = sync.WaitGroup{}
var versionList = []string{"1.0", "1.1", "2.0", "2.1", "2.2", "2.3"}
func main() {
	runtime.GOMAXPROCS(runtime.NumCPU())
	T := time.Now()
	for cityCode, cityName := range tqt.InitCityConf().CityMap {
		wg.Add(1)
		go backUpWeather(cityCode, cityName)
	}
	for i := 0; i < getFileTotal(); i++ {
		wg.Add(1)
		go push()
	}
	select {
	case <-time.After(20 * time.Second):
		log.Println("time out !---------!!!!!!!")
		log.Println(time.Since(T))
		return
	}
	wg.Wait()
	fmt.Println("done")
	log.Println(time.Since(T))
}
func backUpWeather(cityCode string, cityName string) {
	defer wg.Done()
	tqt.NewWeather(cityCode, cityName).PullData(pushFileName, versionList)
}
func push() {
	defer wg.Done()
	tqt.InitPusher().PushFile(<-pushFileName)
}
func getFileTotal() int {
	return tqt.InitCityConf().TotalCity() * len(versionList)
}