sn: return first found EC part when part index is missing

CHANGELOG.md

@@ -4,6 +4,7 @@ Changelog for NeoFS Node
 ## [Unreleased]
 
 ### Added
+- Storage node support GET request with missing part index X-Header (#4033)
 
 ### Fixed
 - Session v2 token was not supported in the new container + eACL RPC (#4056)

go.sum

@@ -191,8 +191,6 @@ github.com/nspcc-dev/neofs-api-go/v2 v2.14.1-0.20240827150555-5ce597aa14ea h1:mK
 github.com/nspcc-dev/neofs-api-go/v2 v2.14.1-0.20240827150555-5ce597aa14ea/go.mod h1:YzhD4EZmC9Z/PNyd7ysC7WXgIgURc9uCG1UWDeV027Y=
 github.com/nspcc-dev/neofs-contract v0.26.1 h1:7Ii7Q4L3au408LOsIWKiSgfnT1g8G9jo3W7381d41T8=
 github.com/nspcc-dev/neofs-contract v0.26.1/go.mod h1:pevVF9OWdEN5bweKxOu6ryZv9muCEtS1ppzYM4RfBIo=
-github.com/nspcc-dev/neofs-sdk-go v1.0.0-rc.20 h1:8ukaQ4w1eiJd7UnrYo6+DTXB7lwjJFDBLdx/3NdIzDo=
-github.com/nspcc-dev/neofs-sdk-go v1.0.0-rc.20/go.mod h1:KtAAolqjEdTNZ8T57FvpWsE/i9/Bpj6wuRPeUs/U85I=
 github.com/nspcc-dev/neofs-sdk-go v1.0.0-rc.20.0.20260703200507-4f450009c764 h1:7zHfAeRQsWx68owaPuyBSIAs4GIUBL5q6Q335PPGjvo=
 github.com/nspcc-dev/neofs-sdk-go v1.0.0-rc.20.0.20260703200507-4f450009c764/go.mod h1:MqOYvyQgnXgEYLVzxQcZ12gp/wrJtDqMzMfjaBsisBM=
 github.com/nspcc-dev/rfc6979 v0.2.4 h1:NBgsdCjhLpEPJZqmC9rciMZDcSY297po2smeaRjw57k=

pkg/local_object_storage/engine/ec.go

@@ -54,26 +54,42 @@ func (e *StorageEngine) ReadECPart(_ context.Context, cnr cid.ID, parent oid.ID,
 // If object is marked as garbage (e.g. via [StorageEngine.MarkGarbage]),
 // GetECPart returns [apistatus.ErrObjectNotFound].
 //
+// If allowReturnAnyPart is true, in cases when specified object part ID cannot be
+// found, StorageEngine returns any part it has for this EC rule. Returned part ID
+// should be found in returned header's attributes.
+//
 // If object is locked (e.g. via [StorageEngine.Lock] or stored locker object),
 // GetECPart ignores expiration, tombstone and garbage marks.
-func (e *StorageEngine) GetECPart(_ context.Context, cnr cid.ID, parent oid.ID, pi iec.PartInfo) (object.Object, io.ReadCloser, error) {
+func (e *StorageEngine) GetECPart(_ context.Context, cnr cid.ID, parent oid.ID, pi iec.PartInfo, allowReturnAnyPart bool) (object.Object, io.ReadCloser, error) {
 	if e.metrics != nil {
 		defer elapsed(e.metrics.AddGetECPartDuration)()
 	}
 
-	var hdr object.Object
-	var stream io.ReadCloser
-	return hdr, stream, e.getECPartFunc(cnr, parent, pi, func(s shardInterface, cnr cid.ID, parent oid.ID, pi iec.PartInfo) error {
-		var err error
-		hdr, stream, err = s.GetECPart(cnr, parent, pi)
-		return err
-	}, func(s shardInterface, partAddr oid.Address) error {
-		h, str, err := s.GetStream(partAddr, true)
-		if err == nil {
-			hdr, stream = *h, str
+	var (
+		hdr    object.Object
+		stream io.ReadCloser
+		gFunc  = func() error {
+			return e.getECPartFunc(cnr, parent, pi, func(s shardInterface, cnr cid.ID, parent oid.ID, pi iec.PartInfo) error {
+				var err error
+				hdr, stream, err = s.GetECPart(cnr, parent, pi)
+				return err
+			}, func(s shardInterface, partAddr oid.Address) error {
+				h, str, err := s.GetStream(partAddr, true)
+				if err == nil {
+					hdr, stream = *h, str
+				}
+				return err
+			})
 		}
-		return err
-	})
+	)
+
+	err := gFunc()
+	if errors.Is(err, apistatus.ErrObjectNotFound) && allowReturnAnyPart {
+		pi.Index = -1
+		return hdr, stream, gFunc()
+	}
+
+	return hdr, stream, err
 }
 
 func (e *StorageEngine) getECPartFunc(cnr cid.ID, parent oid.ID, pi iec.PartInfo, resolveFn func(shardInterface, cid.ID, oid.ID, iec.PartInfo) error,

pkg/local_object_storage/engine/ec_test.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"math"
 	"slices"
 	"strconv"
 	"testing"
@@ -52,7 +53,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 		e := errors.New("any error")
 		require.NoError(t, s.BlockExecution(e))
 
-		_, _, err := s.GetECPart(context.Background(), cnr, parentID, pi)
+		_, _, err := s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		require.Equal(t, e, err)
 
 		_, _, err = s.ReadECPart(context.Background(), cnr, parentID, pi, make([]byte, 40<<10))
@@ -84,7 +85,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 		s := newEngineWithFixedShardOrder([]shardInterface{shardOK, unimplementedShard{}}) // to ensure 2nd shard is not accessed
 		s.metrics = &m
 
-		_, _, _ = s.GetECPart(context.Background(), cnr, parentID, pi)
+		_, _, _ = s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		require.GreaterOrEqual(t, time.Duration(m.getECPart.Load()), sleepTime)
 
 		_, _, _ = s.ReadECPart(context.Background(), cnr, parentID, pi, make([]byte, 40<<10))
@@ -102,7 +103,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 		s.log = l
 
 		require.PanicsWithValue(t, "zero object ID returned as error", func() {
-			_, _, _ = s.GetECPart(context.Background(), cnr, parentID, pi)
+			_, _, _ = s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		})
 
 		lb.AssertEmpty()
@@ -140,7 +141,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 	}
 
 	checkOK := func(t *testing.T, s *StorageEngine) {
-		hdr, rdr, err := s.GetECPart(context.Background(), cnr, parentID, pi)
+		hdr, rdr, err := s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		require.NoError(t, err)
 		assertGetECPartOK(t, partObj, hdr, rdr)
 	}
@@ -155,7 +156,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 		require.NoError(t, rdr.Close())
 	}
 	checkErrorIs := func(t *testing.T, s *StorageEngine, e error) {
-		_, _, err := s.GetECPart(context.Background(), cnr, parentID, pi)
+		_, _, err := s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		require.ErrorIs(t, err, e)
 	}
 	checkErrorIsBuffered := func(t *testing.T, s *StorageEngine, e error) {
@@ -475,7 +476,7 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 
 			require.NoError(t, s.Put(context.Background(), &sysObj, nil))
 
-			hdr, rdr, err := s.GetECPart(context.Background(), cnr, sysObj.GetID(), pi)
+			hdr, rdr, err := s.GetECPart(context.Background(), cnr, sysObj.GetID(), pi, false)
 			require.NoError(t, err)
 			assertGetECPartOK(t, sysObj, hdr, rdr)
 		})
@@ -494,15 +495,51 @@ func TestStorageEngine_GetECPart(t *testing.T) {
 
 		require.NoError(t, s.Put(context.Background(), &linker, nil))
 
-		hdr, rdr, err := s.GetECPart(context.Background(), cnr, parentID, pi)
+		hdr, rdr, err := s.GetECPart(context.Background(), cnr, parentID, pi, false)
 		require.NoError(t, err)
 		assertGetECPartOK(t, linker, hdr, rdr)
 
-		hdr, rdr, err = s.GetECPart(context.Background(), cnr, linker.GetID(), pi)
+		hdr, rdr, err = s.GetECPart(context.Background(), cnr, linker.GetID(), pi, false)
 		require.NoError(t, err)
 		assertGetECPartOK(t, linker, hdr, rdr)
 	})
 
+	t.Run("allow any part found", func(t *testing.T) {
+		piMissing := pi
+		piMissing.Index++
+		piAny := pi
+		piAny.Index = -1
+		piAnother := pi
+		piAnother.Index = math.MaxInt
+
+		anotherPartObj, err := iec.FormObjectForECPart(neofscryptotest.Signer(), parentObj, testutil.RandByteSlice(32), piAnother)
+		require.NoError(t, err)
+
+		shardWithObject := &mockShard{
+			getECPart: map[getECPartKey]getECPartValue{
+				{cnr: cnr, parent: parentID, pi: pi}:        {obj: partObj},
+				{cnr: cnr, parent: parentID, pi: piMissing}: {err: apistatus.ErrObjectNotFound},
+				{cnr: cnr, parent: parentID, pi: piAny}:     {obj: anotherPartObj},
+			},
+		}
+		shardNoObject := &mockShard{
+			getECPart: map[getECPartKey]getECPartValue{
+				{cnr: cnr, parent: parentID, pi: pi}:        {err: apistatus.ErrObjectNotFound},
+				{cnr: cnr, parent: parentID, pi: piMissing}: {err: apistatus.ErrObjectNotFound},
+				{cnr: cnr, parent: parentID, pi: piAny}:     {err: apistatus.ErrObjectNotFound},
+			},
+		}
+
+		e := newEngineWithFixedShardOrder([]shardInterface{shardNoObject, shardWithObject, shardNoObject})
+		checkOK(t, e)
+
+		_, _, err = e.GetECPart(t.Context(), cnr, parentID, piMissing, false)
+		require.ErrorIs(t, err, apistatus.ErrObjectNotFound)
+
+		_, _, err = e.GetECPart(t.Context(), cnr, parentID, piMissing, true)
+		require.NoError(t, err)
+	})
+
 	l, lb := testutil.NewBufferedLogger(t, zap.DebugLevel)
 
 	s := newEngineWithFixedShardOrder([]shardInterface{shardOK, unimplementedShard{}}) // to ensure 2nd shard is not accessed
@@ -1501,7 +1538,7 @@ func testPutTombstoneEC(t *testing.T) {
 				require.ErrorIs(t, err, target)
 				_, err = s.Head(context.Background(), partAddrs[i], true)
 				require.ErrorIs(t, err, target)
-				_, _, err = s.GetECPart(context.Background(), cnr, parent.GetID(), iec.PartInfo{RuleIndex: ruleIdx, Index: i})
+				_, _, err = s.GetECPart(context.Background(), cnr, parent.GetID(), iec.PartInfo{RuleIndex: ruleIdx, Index: i}, false)
 				require.ErrorIs(t, err, target)
 			}
 		}
@@ -1560,7 +1597,7 @@ func testPutTombstoneEC(t *testing.T) {
 			require.NoError(t, err)
 			require.Equal(t, parts[i].CutPayload(), hdr)
 
-			h, rdr, err := s.GetECPart(context.Background(), cnr, parent.GetID(), iec.PartInfo{RuleIndex: ruleIdx, Index: i})
+			h, rdr, err := s.GetECPart(context.Background(), cnr, parent.GetID(), iec.PartInfo{RuleIndex: ruleIdx, Index: i}, false)
 			assertGetStreamOK(t, &h, rdr, err, parts[i])
 		}
 

pkg/local_object_storage/metabase/ec.go

@@ -19,6 +19,8 @@ import (
 
 // ResolveECPart resolves object that carries EC part produced within cnr for
 // parent object and indexed by pi, checks its availability and returns its ID.
+// If [iec.PartInfo] has negative part index, resolves the lowest part index it
+// stores (if any).
 //
 // If the object is not EC part but of [object.TypeTombstone], [object.TypeLock]
 // or [object.TypeLink] type, ResolveECPart returns its ID instead.
@@ -134,6 +136,11 @@ func (db *DB) resolveECPartInMetaBucket(crs *bbolt.Cursor, parent oid.ID, pi iec
 	var rulePref, partPref, typePref []byte
 	var sizeSplitInfo *object.SplitInfo
 	isParent := false
+	var (
+		// for pi.Index < 0 only
+		foundPartMinInd = -1
+		foundPart       oid.ID
+	)
 	for id := range iterAttrVal(crs, object.FilterParentID, parent[:]) {
 		if id.IsZero() {
 			return oid.ID{}, fmt.Errorf("invalid child of %s parent: %w", parent, oid.ErrZero)
@@ -180,14 +187,39 @@ func (db *DB) resolveECPartInMetaBucket(crs *bbolt.Cursor, parent oid.ID, pi iec
 		}
 
 		if partPref == nil {
-			partPref = slices.Concat([]byte{metaPrefixIDAttr}, id[:], []byte(iec.AttributePartIdx), objectcore.MetaAttributeDelimiter, []byte(strconv.Itoa(pi.Index)))
+			partPref = slices.Concat([]byte{metaPrefixIDAttr}, id[:], []byte(iec.AttributePartIdx), objectcore.MetaAttributeDelimiter)
+			if pi.Index >= 0 {
+				partPref = append(partPref, strconv.Itoa(pi.Index)...)
+			}
 		} else {
 			copy(partPref[1:], id[:])
 		}
-		if k, _ = partCrs.Seek(partPref); bytes.Equal(k, partPref) {
+		k, _ = partCrs.Seek(partPref)
+		if !bytes.HasPrefix(k, partPref) {
+			continue
+		}
+		if pi.Index >= 0 {
 			return id, nil
 		}
+
+		ind, err := strconv.Atoi(string(k[len(partPref):]))
+		if err != nil {
+			panic(fmt.Errorf("unexpected EC part index from %X value: %w", k, err))
+		}
+		if foundPartMinInd == -1 {
+			foundPartMinInd = ind
+			foundPart = id
+			continue
+		}
+		if ind < foundPartMinInd {
+			foundPartMinInd = ind
+			foundPart = id
+		}
 	}
+	if pi.Index < 0 && !foundPart.IsZero() {
+		return foundPart, nil
+	}
+
 	if !isParent { // neither tombstone nor lock can be a parent
 		if typePref == nil {
 			typePref = make([]byte, metaIDTypePrefixSize)

pkg/local_object_storage/metabase/ec_test.go

@@ -497,6 +497,28 @@ func TestDB_ResolveECPart(t *testing.T) {
 		})
 	})
 
+	t.Run("negative part index", func(t *testing.T) {
+		db := newDB(t)
+
+		const ruleInd = 1234
+		pi1 := iec.PartInfo{
+			RuleIndex: ruleInd,
+			Index:     0,
+		}
+		pi2 := iec.PartInfo{
+			RuleIndex: ruleInd,
+			Index:     1,
+		}
+
+		p1 := addPart(t, db, pi1)
+		p2 := addPart(t, db, pi2)
+
+		checkOK(t, db, pi1, p1)
+		checkOK(t, db, pi2, p2)
+
+		checkOKWithLen(t, db, iec.PartInfo{RuleIndex: ruleInd, Index: -1}, p1, 1000+pi1.Index)
+	})
+
 	db := newDB(t)
 	require.NoError(t, db.Put(&partObj))
 	checkOK(t, db, pi, partID)

pkg/local_object_storage/shard/ec.go

@@ -36,6 +36,8 @@ func (s *Shard) ReadECPart(cnr cid.ID, parent oid.ID, pi iec.PartInfo, buf []byt
 // parent object and indexed by pi in the underlying metabase, checks its
 // availability and reads it from the underlying BLOB storage. The result is a
 // header and a payload stream that must be closed by caller after processing.
+// If [iec.PartInfo] has negative part index, returned the lowest part index it
+// stores (if any).
 //
 // If the object is not EC part but of [object.TypeTombstone], [object.TypeLock]
 // or [object.TypeLink] type, GetECPart this object instead.