[#1605] node: Stream forwarder requests

Do not hold objects in memory in the forwarded Get/GetRange requests.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/services/object/get/remote.go

@@ -36,8 +36,14 @@ func (exec *execCtx) processNode(ctx context.Context, info client.NodeInfo) bool
 	case err == nil:
 		exec.status = statusOK
 		exec.err = nil
+
+		// both object and err are nil only if the original
+		// request was forwarded to another node and the object
+		// has already been streamed to the requesting party
+		if obj != nil {
 			exec.collectedObject = obj
 			exec.writeCollectedObject()
+		}
 	case errors.As(err, &errRemoved):
 		exec.status = statusINHUMED
 		exec.err = errRemoved

pkg/services/object/get/v2/util.go

@@ -54,12 +54,14 @@ func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStre
 		return nil, err
 	}
 
+	streamWrapper := &streamObjectWriter{stream}
+
 	p := new(getsvc.Prm)
 	p.SetCommonParameters(commonPrm)
 
 	p.WithAddress(addr)
 	p.WithRawFlag(body.GetRaw())
-	p.SetObjectWriter(&streamObjectWriter{stream})
+	p.SetObjectWriter(streamWrapper)
 
 	if !commonPrm.LocalOnly() {
 		var onceResign sync.Once
@@ -105,8 +107,6 @@ func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStre
 
 			var (
 				headWas bool
-				payload []byte
-				obj     = new(objectV2.Object)
 				resp    = new(objectV2.GetResponse)
 			)
 
@@ -149,29 +149,30 @@ func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStre
 
 					headWas = true
 
+					obj := new(objectV2.Object)
+
 					obj.SetObjectID(v.GetObjectID())
 					obj.SetSignature(v.GetSignature())
+					obj.SetHeader(v.GetHeader())
 
-					hdr := v.GetHeader()
+					if err = streamWrapper.WriteHeader(object.NewFromV2(obj)); err != nil {
-					obj.SetHeader(hdr)
+						return nil, fmt.Errorf("could not write object header in Get forwarder: %w", err)
-
+					}
-					payload = make([]byte, 0, hdr.GetPayloadLength())
 				case *objectV2.GetObjectPartChunk:
 					if !headWas {
 						return nil, errWrongMessageSeq
 					}
 
-					payload = append(payload, v.GetChunk()...)
+					if err = streamWrapper.WriteChunk(v.GetChunk()); err != nil {
+						return nil, fmt.Errorf("could not write object chunk in Get forwarder: %w", err)
+					}
 				case *objectV2.SplitInfo:
 					si := object.NewSplitInfoFromV2(v)
 					return nil, object.NewSplitInfoError(si)
 				}
 			}
 
-			obj.SetPayload(payload)
+			return nil, nil
-
-			// convert the object
-			return object.NewFromV2(obj), nil
 		}))
 	}
 
@@ -203,9 +204,11 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 	p := new(getsvc.RangePrm)
 	p.SetCommonParameters(commonPrm)
 
+	streamWrapper := &streamObjectRangeWriter{stream}
+
 	p.WithAddress(addr)
 	p.WithRawFlag(body.GetRaw())
-	p.SetChunkWriter(&streamObjectRangeWriter{stream})
+	p.SetChunkWriter(streamWrapper)
 	p.SetRange(object.NewRangeFromV2(body.GetRange()))
 
 	if !commonPrm.LocalOnly() {
@@ -250,9 +253,6 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 				return nil, fmt.Errorf("could not create Get payload range stream: %w", err)
 			}
 
-			// allocate memory only after receiving a successful response
-			var payload []byte
-
 			resp := new(objectV2.GetRangeResponse)
 
 			for {
@@ -284,11 +284,9 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 				case nil:
 					return nil, fmt.Errorf("unexpected range type %T", v)
 				case *objectV2.GetRangePartChunk:
-					if payload == nil {
+					if err = streamWrapper.WriteChunk(v.GetChunk()); err != nil {
-						payload = make([]byte, 0, body.GetRange().GetLength())
+						return nil, fmt.Errorf("could not write object chunk in GetRange forwarder: %w", err)
 					}
-
-					payload = append(payload, v.GetChunk()...)
 				case *objectV2.SplitInfo:
 					si := object.NewSplitInfoFromV2(v)
 
@@ -296,10 +294,7 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 				}
 			}
 
-			obj := object.New()
+			return nil, nil
-			obj.SetPayload(payload)
-
-			return obj, nil
 		}))
 	}