[go signal] #go

signal.go

package main

import (
    "fmt"
    "time"
    "os"
    "os/signal"
    "syscall"
)

type signalHandler func(s os.Signal, arg interface{})

type signalSet struct {
    m map[os.Signal]signalHandler
}

func signalSetNew() (*signalSet) {
    ss := new(signalSet)
    ss.m = make(map[os.Signal]signalHandler)
    return ss
}


func (set *signalSet) register(s os.Signal, handler signalHandler) {
    if _, found :=set.m[s]; !found {
        set.m[s] = handler
    }
}

func (set *signalSet) handle(s os.Signal, arg interface{}) (err error) {
    if _, found := set.m[s]; found {
        set.m[s](s, arg)
        return nil
    } else {
        return fmt.Errorf("unregister signal: %v", s)
    }
}

func main() {
    go sysSignalHandleDemo()
    time.Sleep(time.Hour) // make the main goroutine wait!
}

func sysSignalHandleDemo() {
    ss := signalSetNew()
    handler := func(s os.Signal, arg interface{}) {
        fmt.Printf("handle signal: %v\n", s)
    }

    ss.register(syscall.SIGINT, handler)
    ss.register(syscall.SIGUSR1, handler)
    ss.register(syscall.SIGUSR2, handler)

    for {
        c := make(chan os.Signal)
        var sigs []os.Signal
        for sig := range ss.m {
            sigs = append(sigs, sig)
        }
        signal.Notify(c)
        sig := <-c

        err := ss.handle(sig, nil)
        if (err != nil) {
            fmt.Printf("unknown signal received: %v\n", sig)
            os.Exit(1)
        }
    }
}