cancel sessions after inactivity

common/signal/timer.go

@@ -0,0 +1,45 @@
+package signal
+
+import (
+	"context"
+	"time"
+)
+
+type ActivityTimer struct {
+	updated chan bool
+	timeout time.Duration
+	ctx     context.Context
+	cancel  context.CancelFunc
+}
+
+func (t *ActivityTimer) UpdateActivity() {
+	select {
+	case t.updated <- true:
+	default:
+	}
+}
+
+func (t *ActivityTimer) run() {
+	for {
+		time.Sleep(t.timeout)
+		select {
+		case <-t.ctx.Done():
+			return
+		case <-t.updated:
+		default:
+			t.cancel()
+			return
+		}
+	}
+}
+
+func CancelAfterInactivity(ctx context.Context, cancel context.CancelFunc, timeout time.Duration) *ActivityTimer {
+	timer := &ActivityTimer{
+		ctx:     ctx,
+		cancel:  cancel,
+		timeout: timeout,
+		updated: make(chan bool, 1),
+	}
+	go timer.run()
+	return timer
+}