Merge pull request #915 from devlights/add-signal-stop

Author: devlights

examples/basic/signals/README.md

@@ -6,3 +6,4 @@
 | ---------------- | --------------------- | ---------------------------------------------------------- |
 | notify.go        | signal_notify         | signal.Notify のサンプルです                               |
 | notifycontext.go | signal_notify_context | Go 1.16 から追加された signal.NotifyContext のサンプルです |
+| stop.go          | signal_stop           | signal.Stop()のサンプルです                                |

examples/basic/signals/examples.go

@@ -15,4 +15,5 @@ func NewRegister() mapping.Register {
 func (r *register) Regist(m mapping.ExampleMapping) {
 	m["signal_notify"] = Notify
 	m["signal_notify_context"] = NotifyContext
+	m["signal_stop"] = Stop
 }

examples/basic/signals/stop.go

@@ -0,0 +1,75 @@
+package signals
+
+import (
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+)
+
+// Stop は、signal.Stop()のサンプルです.
+//
+// signal.Notify()などでハンドル処理を追加した場合
+// ファイルの場合と同様に defer で signal.Stop() を呼ぶべき。
+//
+// > Stop causes package signal to stop relaying incoming signals to c.
+// It undoes the effect of all prior calls to Notify using c. When Stop returns, it is guaranteed that c will receive no more signals.
+//
+// > Stopは、パッケージ・シグナルがcへの受信シグナルのリレーを停止させる。
+// ストップが戻れば、cはそれ以上シグナルを受け取らないことが保証される。
+//
+// # REFERENCES
+//   - https://pkg.go.dev/os/[email protected]#Stop
+func Stop() error {
+	var (
+		l    = log.New(os.Stderr, "", log.Lmicroseconds)
+		pid  = os.Getpid()
+		sigs = make(chan os.Signal, 1)
+
+		sendSig = func() {
+			l.Println(">> SIGUSR1")
+			_ = syscall.Kill(pid, syscall.SIGUSR1)
+		}
+		stopSig = func() {
+			l.Println(">> signal.Stop")
+			signal.Stop(sigs)
+		}
+	)
+	defer close(sigs)
+
+	signal.Notify(sigs, syscall.SIGUSR1, syscall.SIGUSR2)
+	go func() {
+		l.Printf("Signal recv: %v\n", <-sigs)
+	}()
+
+	l.Println("<START>")
+	{
+		sendSig()
+		stopSig()
+		sendSig()
+	}
+	time.Sleep(1 * time.Second)
+	l.Println("< END >")
+
+	/*
+		$ task
+		task: [build] go build -o "/workspaces/try-golang/try-golang" .
+		task: [run] ./try-golang -onetime
+
+		ENTER EXAMPLE NAME: signal_stop
+
+		[Name] "signal_stop"
+		06:03:32.489167 <START>
+		06:03:32.489314 >> SIGUSR1
+		06:03:32.489326 >> signal.Stop
+		06:03:32.489444 >> SIGUSR1
+		06:03:32.489442 Signal recv: user defined signal 1
+		06:03:33.489539 < END >
+
+
+		[Elapsed] 1.000858245s
+	*/
+
+	return nil
+}