package main
import (
"context"
"errors"
"log"
"net/http"
"sync"
"time"
)
type Tracker struct {
wg sync.WaitGroup
}
type App struct {
track Tracker
}
func (a *App) Handle(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusCreated)
a.track.Event("this event")
}
// 同步处理延时较大，使用异步处理。
func (t *Tracker) Event(data string) {
t.wg.Add(1)
go func() {
defer t.wg.Done()
time.Sleep(time.Millisecond)
log.Println(data)
}()
}
func (t *Tracker) Shutdown(ctx context.Context) error {
ch := make(chan struct{})
go func() {
t.wg.Wait()
close(ch)
}()
select {
case <- ch:
return nil
case <- ctx.Done():
return errors.New("timeout")
}
}
func main() {
var a App
ctx, cancel := context.WithTimeout(context.Background(), time.Second * 5)
defer cancel()
err := a.track.Shutdown(ctx)
if err != nil {
log.Println(err)
}
}
