[nspcc-dev#112] api,app: Timers for caches

Add stopTimer and startTimer for caches for ListObjecsV2 to
s3-gw and layer

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

api/layer/layer.go

@@ -98,9 +98,16 @@ type (
 		Get(ctx context.Context, address *object.Address) (*object.Object, error)
 	}
 
+	// Timer provides basic interface for timer  ¯\_(ツ)_/¯.
+	Timer interface {
+		StartTimer()
+		StopTimer()
+	}
+
 	// Client provides S3 API client interface.
 	Client interface {
 		NeoFS
+		Timer
 
 		ListBuckets(ctx context.Context) ([]*BucketInfo, error)
 		GetBucketInfo(ctx context.Context, name string) (*BucketInfo, error)
@@ -468,3 +475,12 @@ func (n *layer) ListObjectVersions(ctx context.Context, p *ListObjectVersionsPar
 	}
 	return &res, nil
 }
+
+func (n *layer) StartTimer() {
+	n.cache.StartTimer()
+}
+
+func (n *layer) StopTimer() {
+	n.log.Info("stopping timer")
+	n.cache.StopTimer()
+}

cmd/s3-gw/app.go

@@ -175,6 +175,8 @@ func (a *App) Server(ctx context.Context) {
 	srv.Handler = router
 	srv.ErrorLog = zap.NewStdLog(a.log)
 
+	go a.obj.StartTimer()
+
 	go func() {
 		a.log.Info("starting server",
 			zap.String("bind", addr))
@@ -202,6 +204,8 @@ func (a *App) Server(ctx context.Context) {
 	ctx, cancel := context.WithTimeout(context.Background(), defaultShutdownTimeout)
 	defer cancel()
 
+	a.obj.StopTimer()
+
 	a.log.Info("stopping server",
 		zap.Error(srv.Shutdown(ctx)))