[#1338] object: Fix range provider in Patch handler

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/services/object/patch/range_provider.go

@@ -25,11 +25,19 @@ type rangeProvider struct {
 	commonPrm *objectUtil.CommonPrm
 
 	localNodeKey *ecdsa.PrivateKey
+
+	originalPayloadLength uint64
 }
 
 var _ patcherSDK.RangeProvider = (*rangeProvider)(nil)
 
 func (r *rangeProvider) GetRange(ctx context.Context, rng *objectSDK.Range) io.Reader {
+	// Remote GetRange request to a container node uses an SDK-client that fails range validation
+	// with zero-length. However, from the patcher's point of view, such request is still valid.
+	if rng.GetOffset() == r.originalPayloadLength && rng.GetLength() == 0 {
+		return &nopReader{}
+	}
+
 	pipeReader, pipeWriter := io.Pipe()
 
 	var rngPrm getsvc.RangePrm
@@ -61,3 +69,9 @@ func (r *rangeProvider) GetRange(ctx context.Context, rng *objectSDK.Range) io.R
 
 	return pipeReader
 }
+
+type nopReader struct{}
+
+func (nopReader) Read(_ []byte) (int, error) {
+	return 0, io.EOF
+}

pkg/services/object/patch/streamer.go

@@ -61,6 +61,7 @@ func (s *Streamer) init(ctx context.Context, req *objectV2.PatchRequest) error {
 	if err != nil {
 		return err
 	}
+	hdr := hdrWithSig.GetHeader()
 
 	commonPrm, err := util.CommonPrmFromV2(req)
 	if err != nil {
@@ -76,6 +77,8 @@ func (s *Streamer) init(ctx context.Context, req *objectV2.PatchRequest) error {
 		commonPrm: commonPrm,
 
 		localNodeKey: s.localNodeKey,
+
+		originalPayloadLength: hdr.GetPayloadLength(),
 	}
 
 	putstm, err := s.putSvc.Put()
@@ -83,7 +86,6 @@ func (s *Streamer) init(ctx context.Context, req *objectV2.PatchRequest) error {
 		return err
 	}
 
-	hdr := hdrWithSig.GetHeader()
 	oV2 := new(objectV2.Object)
 	hV2 := new(objectV2.Header)
 	oV2.SetHeader(hV2)