implemented event and req

pkg/utils/interrupt/README.md

@@ -0,0 +1,2 @@
+# interrupt
+Handle shutdowns cleanly and enable hot reload

pkg/utils/interrupt/main.go

@@ -0,0 +1,153 @@
+// Package interrupt is a library for providing handling for Ctrl-C/Interrupt
+// handling and triggering callbacks for such things as closing files, flushing
+// buffers, and other elements of graceful shutdowns.
+package interrupt
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"runtime"
+
+	"lol.mleku.dev/log"
+	"utils.orly/atomic"
+	"utils.orly/qu"
+)
+
+// HandlerWithSource is an interrupt handling closure and the source location
+// that it was sent from.
+type HandlerWithSource struct {
+	Source string
+	Fn     func()
+}
+
+var (
+	// RestartRequested is set true after restart is requested.
+	RestartRequested bool // = true
+	requested        atomic.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)
+
+	interruptCallbacks       []func()
+	interruptCallbackSources []string
+)
+
+// Listener listens for interrupt signals, registers interrupt callbacks, and
+// responds to custom shutdown signals as required
+func Listener() {
+	invokeCallbacks := func() {
+		// run handlers in LIFO order.
+		for i := range interruptCallbacks {
+			idx := len(interruptCallbacks) - 1 - i
+			log.T.F(
+				"running callback %d from %s", idx,
+				interruptCallbackSources[idx],
+			)
+			interruptCallbacks[idx]()
+		}
+		log.D.Ln("interrupt handlers finished")
+		HandlersDone.Q()
+		if RestartRequested {
+			Restart()
+		} else {
+			os.Exit(0)
+		}
+	}
+out:
+	for {
+		select {
+		case _ = <-ch:
+			fmt.Fprintf(os.Stderr, "\r")
+			requested.Store(true)
+			invokeCallbacks()
+			break out
+
+		case <-ShutdownRequestChan.Wait():
+			log.W.Ln("received shutdown request - shutting down...")
+			requested.Store(true)
+			invokeCallbacks()
+			break out
+
+		case handler := <-addHandlerChan:
+			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)
+	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)
+	log.D.Ln("interrupt requested", f, l, requested.Load())
+	if requested.Load() {
+		log.D.Ln("requested again")
+		return
+	}
+	requested.Store(true)
+	ShutdownRequestChan.Q()
+	var ok bool
+	select {
+	case _, ok = <-ShutdownRequestChan:
+	default:
+	}
+	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() {
+	RestartRequested = true
+	log.D.Ln("requesting restart")
+	Request()
+}
+
+// Requested returns true if an interrupt has been requested
+func Requested() bool {
+	return requested.Load()
+}

pkg/utils/interrupt/restart.go

@@ -0,0 +1,26 @@
+//go:build linux
+
+package interrupt
+
+import (
+	"lol.mleku.dev/log"
+	"os"
+	"syscall"
+
+	"github.com/kardianos/osext"
+)
+
+// Restart uses syscall.Exec to restart the process. macOS and Windows are not
+// implemented, currently.
+func Restart() {
+	log.D.Ln("restarting")
+	file, e := osext.Executable()
+	if e != nil {
+		log.E.Ln(e)
+		return
+	}
+	e = syscall.Exec(file, os.Args, os.Environ())
+	if e != nil {
+		log.F.Ln(e)
+	}
+}

pkg/utils/interrupt/restart_darwin.go

@@ -0,0 +1,20 @@
+package interrupt
+
+func Restart() {
+	// TODO: test this thing actually works!
+	// log.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:]...)
+	// log.D.Ln("windows restart done")
+	// if err := cmd.Start(); log.Fail(err) {
+	// }
+	// // select{}
+	// os.Exit(0)
+}

pkg/utils/interrupt/restart_windows.go

@@ -0,0 +1,20 @@
+package interrupt
+
+func Restart() {
+	// TODO: test this thing actually works!
+	// log.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:]...)
+	// log.D.Ln("windows restart done")
+	// if err := cmd.Start(); log.Fail(err) {
+	// }
+	// // select{}
+	// os.Exit(0)
+}

pkg/utils/interrupt/sigterm.go

@@ -0,0 +1,12 @@
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package interrupt
+
+import (
+	"os"
+	"syscall"
+)
+
+func init() {
+	signals = []os.Signal{os.Interrupt, syscall.SIGTERM}
+}