http.go

package main

func main() {
	// ... setup ...

	l, err := net.Listen("tcp", *laddr)
	if err != nil {
		log.Fatal(err)
	}

	sig := make(chan os.Signal)
	signal.Notify(sig, os.Signal(syscall.SIGTERM))

	graceful := make(chan bool, 1)
	go func() {
		tick := time.Tick(time.Minute)

		for {
			select {
			case <-sig:
				measure.Count("SIGTERM")
				graceful <- true
				l.Close()
				return
			case <-tick:
				things.Flush()
			}
		}
	}()

	var wg sync.WaitGroup
	m := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		wg.Add(1)
		defer wg.Done()
		http.DefaultServeMux.ServeHTTP(w, r)
	})

	defer things.Flush()
	err := http.Serve(l, m)
	wg.Wait() // maybe time this out, in case a request is hanging?
	if err != nil {
		select {
		case <-graceful:
			// There is a race here still, I think. The server
			// could have errored between sending on graceful and
			// l.Close() - I'm not sure I care.
		default:
			log.Fatal(err)
		}
	}
}