add g.Listen for automatic signal handling feature

frame/g/g_func.go

@@ -19,11 +19,16 @@ func NewVar(i interface{}, safe ...bool) *Var {
 	return gvar.New(i, safe...)
 }
 
-// Wait blocks until:
-// 1. All the web servers shutdown, it does nothing if there's no running web server.
-// 2. Shutdown signals received and all registered shutdown handlers done.
+// Wait is an alias of ghttp.Wait, which blocks until all the web servers shutdown.
+// It's commonly used in multiple servers situation.
 func Wait() {
 	ghttp.Wait()
+}
+
+// Listen is an alias of gproc.Listen, which handles the signals received and automatically
+// calls registered signal handler functions.
+// It blocks until shutdown signals received and all registered shutdown handlers done.
+func Listen() {
 	gproc.Listen()
 }
 

os/gproc/gproc_signal.go

@@ -7,6 +7,7 @@
 package gproc
 
 import (
+	"github.com/gogf/gf/internal/intlog"
 	"os"
 	"os/signal"
 	"sync"
@@ -64,6 +65,7 @@ func Listen() {
 	for {
 		wg := sync.WaitGroup{}
 		sig = <-sigChan
+		intlog.Printf(`signal received: %s`, sig.String())
 		if handlers, ok := signalHandlerMap[sig]; ok {
 			for _, handler := range handlers {
 				wg.Add(1)