about time this thing was out there (even if we borrowed it ;)

.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
+# Editor-based HTTP Client requests
+/httpRequests/

.idea/interrupt.iml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="Go" enabled="true" />
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/interrupt.iml" filepath="$PROJECT_DIR$/.idea/interrupt.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

cmd/ctrlctest.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/p9c/pod/pkg/util/interrupt"
+)
+
+func main() {
+	interrupt.AddHandler(func() {
+		fmt.Println("IT'S THE END OF THE WORLD!")
+	})
+	<-interrupt.HandlersDone
+}

log.go

@@ -0,0 +1,42 @@
+package interrupt
+
+import (
+	"github.com/p9c/pod/pkg/logg"
+)
+
+var subsystem = logg.AddLoggerSubsystem()
+var F, E, W, I, D, T logg.LevelPrinter = logg.GetLogPrinterSet(subsystem)
+
+func init() {
+	// to filter out this package, uncomment the following
+	// var _ = logg.AddFilteredSubsystem(subsystem)
+	
+	// to highlight this package, uncomment the following
+	// var _ = logg.AddHighlightedSubsystem(subsystem)
+	
+	// these are here to test whether they are working
+	// F.Ln("F.Ln")
+	// E.Ln("E.Ln")
+	// W.Ln("W.Ln")
+	// I.Ln("I.Ln")
+	// D.Ln("D.Ln")
+	// F.Ln("T.Ln")
+	// F.F("%s", "F.F")
+	// E.F("%s", "E.F")
+	// W.F("%s", "W.F")
+	// I.F("%s", "I.F")
+	// D.F("%s", "D.F")
+	// T.F("%s", "T.F")
+	// F.C(func() string { return "F.C" })
+	// E.C(func() string { return "E.C" })
+	// W.C(func() string { return "W.C" })
+	// I.C(func() string { return "I.C" })
+	// D.C(func() string { return "D.C" })
+	// T.C(func() string { return "T.C" })
+	// F.C(func() string { return "F.C" })
+	// E.Chk(errors.New("E.Chk"))
+	// W.Chk(errors.New("W.Chk"))
+	// I.Chk(errors.New("I.Chk"))
+	// D.Chk(errors.New("D.Chk"))
+	// T.Chk(errors.New("T.Chk"))
+}

main.go

@@ -0,0 +1,187 @@
+package interrupt
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"os/signal"
+	"runtime"
+	"strings"
+	"syscall"
+	
+	uberatomic "go.uber.org/atomic"
+	
+	"github.com/p9c/pod/pkg/util/qu"
+	
+	"github.com/kardianos/osext"
+)
+
+type HandlerWithSource struct {
+	Source string
+	Fn     func()
+}
+
+var (
+	Restart bool // = true
+	requested uberatomic.Bool
+	// ch is used to receive SIGINT (Ctrl+C) signals.
+	ch chan os.Signal
+	// signals is the list of signals that cause the interrupt
+	signals = []os.Signal{os.Interrupt}
+	// ShutdownRequestChan is a channel that can receive shutdown requests
+	ShutdownRequestChan = qu.T()
+	// addHandlerChan is used to add an interrupt handler to the list of
+	// handlers to be invoked on SIGINT (Ctrl+C) signals.
+	addHandlerChan = make(chan HandlerWithSource)
+	// HandlersDone is closed after all interrupt handlers run the first time
+	// an interrupt is signaled.
+	HandlersDone = make(qu.C)
+)
+
+var interruptCallbacks []func()
+var interruptCallbackSources []string
+
+// Listener listens for interrupt signals, registers interrupt callbacks,
+// and responds to custom shutdown signals as required
+func Listener() {
+	invokeCallbacks := func() {
+		D.Ln(
+			"running interrupt callbacks",
+			len(interruptCallbacks),
+			strings.Repeat(" ", 48),
+			interruptCallbackSources,
+		)
+		// run handlers in LIFO order.
+		for i := range interruptCallbacks {
+			idx := len(interruptCallbacks) - 1 - i
+			D.Ln("running callback", idx, interruptCallbackSources[idx])
+			interruptCallbacks[idx]()
+		}
+		D.Ln("interrupt handlers finished")
+		HandlersDone.Q()
+		if Restart {
+			var file string
+			var e error
+			file, e = osext.Executable()
+			if e != nil {
+				E.Ln(e)
+				return
+			}
+			D.Ln("restarting")
+			if runtime.GOOS != "windows" {
+				e = syscall.Exec(file, os.Args, os.Environ())
+				if e != nil {
+					F.Ln(e)
+				}
+			} else {
+				D.Ln("doing windows restart")
+				
+				// procAttr := new(os.ProcAttr)
+				// procAttr.Files = []*os.File{os.Stdin, os.Stdout, os.Stderr}
+				// os.StartProcess(os.Args[0], os.Args[1:], procAttr)
+				
+				var s []string
+				// s = []string{"cmd.exe", "/C", "start"}
+				s = append(s, os.Args[0])
+				// s = append(s, "--delaystart")
+				s = append(s, os.Args[1:]...)
+				cmd := exec.Command(s[0], s[1:]...)
+				D.Ln("windows restart done")
+				if e = cmd.Start(); E.Chk(e) {
+				}
+				// // select{}
+				// os.Exit(0)
+			}
+		}
+		// time.Sleep(time.Second * 3)
+		// os.Exit(1)
+		// close(HandlersDone)
+	}
+out:
+	for {
+		select {
+		case sig := <-ch:
+			// if !requested {
+			// 	L.Printf("\r>>> received signal (%s)\n", sig)
+			D.Ln("received interrupt signal", sig)
+			requested.Store(true)
+			invokeCallbacks()
+			// pprof.Lookup("goroutine").WriteTo(os.Stderr, 2)
+			// }
+			break out
+		case <-ShutdownRequestChan.Wait():
+			// if !requested {
+			W.Ln("received shutdown request - shutting down...")
+			requested.Store(true)
+			invokeCallbacks()
+			break out
+			// }
+		case handler := <-addHandlerChan:
+			// if !requested {
+			// D.Ln("adding handler")
+			interruptCallbacks = append(interruptCallbacks, handler.Fn)
+			interruptCallbackSources = append(interruptCallbackSources, handler.Source)
+			// }
+		case <-HandlersDone.Wait():
+			break out
+		}
+	}
+}
+
+// AddHandler adds a handler to call when a SIGINT (Ctrl+C) is received.
+func AddHandler(handler func()) {
+	// Create the channel and start the main interrupt handler which invokes all other callbacks and exits if not
+	// already done.
+	_, loc, line, _ := runtime.Caller(1)
+	msg := fmt.Sprintf("%s:%d", loc, line)
+	D.Ln("handler added by:", msg)
+	if ch == nil {
+		ch = make(chan os.Signal)
+		signal.Notify(ch, signals...)
+		go Listener()
+	}
+	addHandlerChan <- HandlerWithSource{
+		msg, handler,
+	}
+}
+
+// Request programmatically requests a shutdown
+func Request() {
+	_, f, l, _ := runtime.Caller(1)
+	D.Ln("interrupt requested", f, l, requested.Load())
+	if requested.Load() {
+		D.Ln("requested again")
+		return
+	}
+	requested.Store(true)
+	ShutdownRequestChan.Q()
+	// qu.PrintChanState()
+	var ok bool
+	select {
+	case _, ok = <-ShutdownRequestChan:
+	default:
+	}
+	D.Ln("shutdownrequestchan", ok)
+	if ok {
+		close(ShutdownRequestChan)
+	}
+}
+
+// GoroutineDump returns a string with the current goroutine dump in order to show what's going on in case of timeout.
+func GoroutineDump() string {
+	buf := make([]byte, 1<<18)
+	n := runtime.Stack(buf, true)
+	return string(buf[:n])
+}
+
+// RequestRestart sets the reset flag and requests a restart
+func RequestRestart() {
+	Restart = true
+	D.Ln("requesting restart")
+	Request()
+}
+
+// Requested returns true if an interrupt has been requested
+func Requested() bool {
+	return requested.Load()
+}

sigterm.go

@@ -0,0 +1,13 @@
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package interrupt
+
+import (
+	"os"
+	"syscall"
+)
+
+func init() {
+
+	signals = []os.Signal{os.Interrupt, syscall.SIGTERM}
+}