[golang]golang signal.Notify 信号，如何优雅的退出

func Notify(c chan<- os.Signal, sig ...os.Signal) 

ch := make(chan os.Signal, 1)
    signal.Notify(ch, syscall.SIGHUP, syscall.SIGQUIT, syscall.SIGTERM, syscall.SIGSTOP, syscall.SIGUSR1)
    for {
        s := <-ch
        switch s {
        case syscall.SIGQUIT:
            log.Infof("SIGSTOP")
            return
        case syscall.SIGSTOP:
            log.Infof("SIGSTOP")
            return
        case syscall.SIGHUP:
            log.Infof("SIGHUP")
            return
        case syscall.SIGKILL:
            log.Infof("SIGKILL")
            return
        case syscall.SIGUSR1:
            log.Infof("SIGUSR1")
            return
        default:
            log.Infof("default")
            return
        }
    }

package main
 
import (
        "fmt"
        "os"
        "os/signal"
        "syscall"
        "time"
)
 
func main() {
        //创建监听退出chan
        c := make(chan os.Signal)
        //监听指定信号 ctrl+c kill
        signal.Notify(c, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, 
                         syscall.SIGQUIT, syscall.SIGUSR1, syscall.SIGUSR2)
        go func() {
                for s := range c {
                        switch s {
                        case syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT:
                                fmt.Println("Program Exit...", s)
                                GracefullExit()
                        case syscall.SIGUSR1:
                                fmt.Println("usr1 signal", s)
                        case syscall.SIGUSR2:
                                fmt.Println("usr2 signal", s)
                        default:
                                fmt.Println("other signal", s)
                        }
                }
        }()
 
        fmt.Println("Program Start...")
        sum := 0
        for {
                sum++
                fmt.Println("sum:", sum)
                time.Sleep(time.Second)
        }
}
 
func GracefullExit() {
        fmt.Println("Start Exit...")
        fmt.Println("Execute Clean...")
        fmt.Println("End Exit...")
        os.Exit(0)
}