refacotr: move signal handling and pprof to grace package

weed/util/grace/signal_handling.go

@@ -0,0 +1,46 @@
+// +build !plan9
+
+package grace
+
+import (
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+)
+
+var signalChan chan os.Signal
+var hooks = make([]func(), 0)
+var hookLock sync.Mutex
+
+func init() {
+	signalChan = make(chan os.Signal, 1)
+	signal.Ignore(syscall.SIGHUP)
+	signal.Notify(signalChan,
+		os.Interrupt,
+		os.Kill,
+		syscall.SIGALRM,
+		// syscall.SIGHUP,
+		syscall.SIGINT,
+		syscall.SIGTERM,
+		// syscall.SIGQUIT,
+	)
+	go func() {
+		for _ = range signalChan {
+			for _, hook := range hooks {
+				hook()
+			}
+			os.Exit(0)
+		}
+	}()
+}
+
+func OnInterrupt(fn func()) {
+	// prevent reentry
+	hookLock.Lock()
+	defer hookLock.Unlock()
+
+	// deal with control+c,etc
+	// controlling terminal close, daemon not exit
+	hooks = append(hooks, fn)
+}