[#0] tree: Split GetOpLog stream

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/services/tree/sync.go

@@ -219,38 +219,57 @@ func (s *Service) startStream(ctx context.Context, cid cid.ID, treeID string,
 
 	rawCID := make([]byte, sha256.Size)
 	cid.Encode(rawCID)
+	from := height
+	const batchSize = 10_000
 
-	req := &GetOpLogRequest{
-		Body: &GetOpLogRequest_Body{
-			ContainerId: rawCID,
-			TreeId:      treeID,
-			Height:      height,
-		},
-	}
-	if err := SignMessage(req, s.key); err != nil {
-		return err
-	}
-
-	c, err := treeClient.GetOpLog(ctx, req)
-	if err != nil {
-		return fmt.Errorf("can't initialize client: %w", err)
-	}
-	res, err := c.Recv()
-	for ; err == nil; res, err = c.Recv() {
-		lm := res.GetBody().GetOperation()
-		m := &pilorama.Move{
-			Parent: lm.GetParentId(),
-			Child:  lm.GetChildId(),
+	for {
+		count := 0
+		req := &GetOpLogRequest{
+			Body: &GetOpLogRequest_Body{
+				ContainerId: rawCID,
+				TreeId:      treeID,
+				Height:      from,
+			},
 		}
-		if err := m.Meta.FromBytes(lm.GetMeta()); err != nil {
+		if err := SignMessage(req, s.key); err != nil {
 			return err
 		}
-		opsCh <- m
-	}
-	if !errors.Is(err, io.EOF) {
+
+		streamCtx, cancel := context.WithCancel(ctx)
+		defer cancel()
+
+		c, err := treeClient.GetOpLog(streamCtx, req)
+		if err != nil {
+			return fmt.Errorf("can't initialize client: %w", err)
+		}
+		res, err := c.Recv()
+		for ; err == nil; res, err = c.Recv() {
+			lm := res.GetBody().GetOperation()
+			m := &pilorama.Move{
+				Parent: lm.GetParentId(),
+				Child:  lm.GetChildId(),
+			}
+			if err := m.Meta.FromBytes(lm.GetMeta()); err != nil {
+				return err
+			}
+			from = m.Time
+			opsCh <- m
+			count++
+			if count == batchSize {
+				break // c.Recv()
+			}
+		}
+		if err == nil {
+			// count == batchSize
+			// close current stream and start new one
+			cancel()
+			continue
+		}
+		if errors.Is(err, io.EOF) {
+			return nil
+		}
 		return err
 	}
-	return nil
 }
 
 // synchronizeTree synchronizes operations getting them from different nodes.