finally a complete working go daemon

.gitignore

@@ -79,4 +79,5 @@ dkms.conf
 ### USER MODIFIED ###
 c-daemon/bin/
 go-daemon/bin/
-go-daemon/local-ref.sh
+go-daemon/local-ref.sh
+tmp.go

go-daemon/go.mod

@@ -6,5 +6,6 @@ require github.com/sevlyar/go-daemon v0.1.6
 
 require (
 	github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 // indirect
+	golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b // indirect
 	golang.org/x/sys v0.10.0 // indirect
 )

go-daemon/go.sum

@@ -2,5 +2,7 @@ github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0 h1:iQTw/8FWTuc7uia
 github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0/go.mod h1:1NbS8ALrpOvjt0rHPNLyCIeMtbizbir8U//inJ+zuB8=
 github.com/sevlyar/go-daemon v0.1.6 h1:EUh1MDjEM4BI109Jign0EaknA2izkOyi0LV3ro3QQGs=
 github.com/sevlyar/go-daemon v0.1.6/go.mod h1:6dJpPatBT9eUwM5VCw9Bt6CdX9Tk6UWvhW3MebLDRKE=
+golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b h1:r+vk0EmXNmekl0S0BascoeeoHk/L7wmaW2QF90K+kYI=
+golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
 golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

go-daemon/godaemon1.go

@@ -1,51 +1,95 @@
 package main
 
 import (
-	"godaemon1/service"
 	"log"
 	"os"
-	"os/signal"
+	"os/exec"
+	"syscall"
 	"time"
 
 	"github.com/sevlyar/go-daemon"
+	"golang.org/x/exp/slices"
 )
 
+const pidFile = "/etc/godaemon1/godaemon1.pid"
+const ExecutablePath = "/usr/bin/godaemon1"
+
 func main() {
-	cntxt := &daemon.Context{
-		PidFileName: "/etc/godaemon1/godaemon1.pid",
-		PidFilePerm: 0644,
-		LogFileName: "/etc/godaemon1/godaemon1.log",
-		LogFilePerm: 0640,
-		WorkDir:     "./",
-		Umask:       027,
-	}
-
-	d, err := cntxt.Reborn()
-	if err != nil {
-		log.Fatal("Unable to run: ", err)
-	}
-	if d != nil {
-		return
-	}
-	defer cntxt.Release()
-
-	// TODO make both in external package service these lines but also async
-	sigChannel := make(chan os.Signal, 1)
-	signal.Notify(sigChannel)
-
-	go func() {
-		for {
-			s := <-sigChannel
-			service.SigHandler(s)
+	if len(os.Args) == 2 && slices.Contains([]string{"start", "stop", "restart"}, os.Args[1]) {
+		switch os.Args[1] {
+		case "start":
+			cntxt := &daemon.Context{
+				PidFileName: pidFile,
+				PidFilePerm: 0644,
+				LogFileName: "/etc/godaemon1/godaemon1.log",
+				LogFilePerm: 0640,
+				WorkDir:     "./",
+				Umask:       027,
+				Args:        []string{ExecutablePath, "start"},
+			}
+			d, err := cntxt.Reborn()
+			if err != nil {
+				log.Fatal("Daemon ERROR:", err)
+			}
+			if d != nil {
+				log.Println("Daemon call stack: ", d)
+				return
+			}
+			defer cntxt.Release()
+			log.Print("- - - - - - - - - - - - - - -")
+			log.Print("daemon started")
+		case "stop":
+			i, _ := daemon.ReadPidFile(pidFile)
+			Stop(i, 15)
+			os.Exit(0)
+		case "restart":
+			i, _ := daemon.ReadPidFile(pidFile)
+			Restart(i, 15)
+			os.Exit(0)
 		}
-	}()
-
-	log.Print("- - - - - - - - - - - - - - -")
-	log.Print("daemon started")
+	}
 
 	for {
 		Info()
-		time.Sleep(10 * time.Second)
+		time.Sleep(2 * time.Second)
 	}
 
 }
+
+func Start(executable string) {
+	if executable == "" {
+		executable = ExecutablePath
+	}
+	cmd := exec.Command(ExecutablePath, "start")
+	if err := cmd.Run(); err != nil {
+		log.Println("Error: ", err)
+	}
+}
+
+func Restart(pid, signal int) {
+	log.Println("Restart Signal Caught")
+
+	// FILLME what you want to do before restarting daemon?
+
+	Stop(pid, signal)
+
+	// FILLME what you want to do after stopping daemon and before starting it again?
+
+	Start("")
+
+	// FILLME what you want to do after starting a new daemon
+}
+
+// Stop Ahenkd Daemon with a specific PID
+// do not forget to use also os.Exit() when using in ExecStop
+func Stop(pid, signal int) {
+	log.Println("Stop Signal Caught")
+
+	// FILLME what you want to do before stopping daemon?
+
+	if err := syscall.Kill(pid, syscall.Signal(signal)); err == nil {
+		log.Printf("Ahenk Daemon with pid number %v Successfully stopped", pid)
+	} else {
+		log.Fatal(err)
+	}
+}

go-daemon/godaemon1.service

@@ -6,7 +6,8 @@ After=multi-user.target
 Type=forking
 User=root
 Group=root
-ExecStart=/usr/bin/godaemon1
+ExecStart=/usr/bin/godaemon1 start
+ExecStop=/usr/bin/godaemon1 stop
 PIDFile=/etc/godaemon1/godaemon1.pid
 
 PrivateTmp=false

go-daemon/service/restart.go

@@ -1,21 +0,0 @@
-package service
-
-import (
-	"log"
-	"os"
-	"syscall"
-)
-
-func Restart() error {
-	log.Println("Restart Signal Caught")
-
-	// TODO what you want to do before restarting daemon?
-
-	self, err := os.Executable()
-	if err != nil {
-		return err
-	}
-	args := os.Args
-	env := os.Environ()
-	return syscall.Exec(self, args, env)
-}

go-daemon/service/sighandler.go

@@ -1,19 +0,0 @@
-package service
-
-import (
-	"log"
-	"os"
-	"syscall"
-)
-
-func SigHandler(signal os.Signal) {
-	if signal == syscall.SIGTERM {
-		log.Println("Got signal: SIGTERM")
-	} else if signal == syscall.SIGINT {
-		log.Println("Got signal: SIGINT")
-	} else if signal == syscall.SIGKILL {
-		log.Println("Got signal: SIGINT")
-	} else {
-		log.Printf("Got another signal: %v\n", signal)
-	}
-}