Refactoring for PR.

Signed-off-by: Aleksey Sin <asin@ozon.ru>

Author: Aleksey Sin

pkg/store/proxy.go

@@ -302,8 +302,9 @@ func (s *ProxyStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesSe
 			}
 
 			var storeTypeStr string
-			if st.StoreType() != nil {
-				storeTypeStr = st.StoreType().String()
+			storeType := st.StoreType()
+			if storeType != nil {
+				storeTypeStr = storeType.String()
 			}
 			metrics := &storeRequestMetrics{
 				withPayload:       s.metrics.timeToFirstByte.WithLabelValues(st.LabelSetsString(), storeTypeStr, withPayloadLabel),
@@ -312,10 +313,10 @@ func (s *ProxyStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesSe
 				queryTimeoutCount: s.metrics.queryTimeoutCount.WithLabelValues(st.LabelSetsString(), storeTypeStr),
 			}
 
-			seriesSet = append(seriesSet, startStreamSeriesSet(seriesCtx, s.logger, closeSeries,
-				wg, sc, respSender, st.String(), !r.PartialResponseDisabled, s.responseTimeout, metrics))
 			// Schedule streamSeriesSet that translates gRPC streamed response
 			// into seriesSet (if series) or respCh if warnings.
+			seriesSet = append(seriesSet, startStreamSeriesSet(seriesCtx, s.logger, closeSeries,
+				wg, sc, respSender, st.String(), !r.PartialResponseDisabled, s.responseTimeout, metrics))
 		}
 
 		level.Debug(s.logger).Log("msg", strings.Join(storeDebugMsgs, ";"))
@@ -380,6 +381,16 @@ type recvResponse struct {
 	err error
 }
 
+func startFrameCtx(responseTimeout time.Duration) (context.Context, context.CancelFunc) {
+	frameTimeoutCtx := context.Background()
+	var cancel context.CancelFunc
+	if responseTimeout != 0 {
+		frameTimeoutCtx, cancel = context.WithTimeout(frameTimeoutCtx, responseTimeout)
+		return frameTimeoutCtx, cancel
+	}
+	return frameTimeoutCtx, nil
+}
+
 func startStreamSeriesSet(
 	ctx context.Context,
 	logger log.Logger,
@@ -410,10 +421,8 @@ func startStreamSeriesSet(
 		defer wg.Done()
 		defer close(s.recvCh)
 		for {
-			frameTimeoutCtx := context.Background()
-			var cancel context.CancelFunc
-			if s.responseTimeout != 0 {
-				frameTimeoutCtx, cancel = context.WithTimeout(frameTimeoutCtx, s.responseTimeout)
+			frameTimeoutCtx, cancel := startFrameCtx(s.responseTimeout)
+			if cancel != nil {
 				defer cancel()
 			}
 			rCh := make(chan *recvResponse, 1)