[#277] getsvc: Refactor errors

Move errors to separate files.
Use zap.Error for error logging.

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

cmd/frostfs-node/object.go

@@ -336,17 +336,14 @@ func createGetService(c *cfg, keyStorage *util.KeyStorage, traverseGen *util.Tra
 	ls := c.cfgObject.cfgLocalStorage.localStorage
 
 	return getsvc.New(
-		getsvc.WithLogger(c.log),
+		keyStorage,
-		getsvc.WithLocalStorageEngine(ls),
+		c.netMapSource,
-		getsvc.WithClientConstructor(coreConstructor),
+		ls,
-		getsvc.WithTraverserGenerator(
+		traverseGen.WithTraverseOptions(
-			traverseGen.WithTraverseOptions(
+			placement.SuccessAfter(1),
-				placement.SuccessAfter(1),
-			),
 		),
-		getsvc.WithNetMapSource(c.netMapSource),
+		coreConstructor,
-		getsvc.WithKeyStorage(keyStorage),
+		getsvc.WithLogger(c.log))
-	)
 }
 
 func createGetServiceV2(sGet *getsvc.Service, keyStorage *util.KeyStorage) *getsvcV2.Service {

pkg/services/object/get/assemble.go

@@ -11,9 +11,9 @@ import (
 	"go.uber.org/zap"
 )
 
-func (exec *execCtx) assemble(ctx context.Context) {
+func (r *request) assemble(ctx context.Context) {
-	if !exec.canAssemble() {
+	if !r.canAssemble() {
-		exec.log.Debug(logs.GetCanNotAssembleTheObject)
+		r.log.Debug(logs.GetCanNotAssembleTheObject)
 		return
 	}
 
@@ -28,35 +28,35 @@ func (exec *execCtx) assemble(ctx context.Context) {
 	//  - the assembly process is expected to be handled on a container node
 	//    only since the requests forwarding mechanism presentation; such the
 	//    node should have enough rights for getting any child object by design.
-	exec.prm.common.ForgetTokens()
+	r.prm.common.ForgetTokens()
 
 	// Do not use forwarding during assembly stage.
 	// Request forwarding closure inherited in produced
 	// `execCtx` so it should be disabled there.
-	exec.disableForwarding()
+	r.disableForwarding()
 
-	exec.log.Debug(logs.GetTryingToAssembleTheObject)
+	r.log.Debug(logs.GetTryingToAssembleTheObject)
 
-	assembler := newAssembler(exec.address(), exec.splitInfo(), exec.ctxRange(), exec)
+	assembler := newAssembler(r.address(), r.splitInfo(), r.ctxRange(), r)
 
-	exec.log.Debug(logs.GetAssemblingSplittedObject,
+	r.log.Debug(logs.GetAssemblingSplittedObject,
-		zap.Stringer("address", exec.address()),
+		zap.Stringer("address", r.address()),
-		zap.Uint64("range_offset", exec.ctxRange().GetOffset()),
+		zap.Uint64("range_offset", r.ctxRange().GetOffset()),
-		zap.Uint64("range_length", exec.ctxRange().GetLength()),
+		zap.Uint64("range_length", r.ctxRange().GetLength()),
 	)
-	defer exec.log.Debug(logs.GetAssemblingSplittedObjectCompleted,
+	defer r.log.Debug(logs.GetAssemblingSplittedObjectCompleted,
-		zap.Stringer("address", exec.address()),
+		zap.Stringer("address", r.address()),
-		zap.Uint64("range_offset", exec.ctxRange().GetOffset()),
+		zap.Uint64("range_offset", r.ctxRange().GetOffset()),
-		zap.Uint64("range_length", exec.ctxRange().GetLength()),
+		zap.Uint64("range_length", r.ctxRange().GetLength()),
 	)
 
-	obj, err := assembler.Assemble(ctx, exec.prm.objWriter)
+	obj, err := assembler.Assemble(ctx, r.prm.objWriter)
 	if err != nil {
-		exec.log.Warn(logs.GetFailedToAssembleSplittedObject,
+		r.log.Warn(logs.GetFailedToAssembleSplittedObject,
 			zap.Error(err),
-			zap.Stringer("address", exec.address()),
+			zap.Stringer("address", r.address()),
-			zap.Uint64("range_offset", exec.ctxRange().GetOffset()),
+			zap.Uint64("range_offset", r.ctxRange().GetOffset()),
-			zap.Uint64("range_length", exec.ctxRange().GetLength()),
+			zap.Uint64("range_length", r.ctxRange().GetLength()),
 		)
 	}
 
@@ -68,27 +68,27 @@ func (exec *execCtx) assemble(ctx context.Context) {
 
 	switch {
 	default:
-		exec.status = statusUndefined
+		r.status = statusUndefined
-		exec.err = err
+		r.err = err
 	case err == nil:
-		exec.status = statusOK
+		r.status = statusOK
-		exec.err = nil
+		r.err = nil
-		exec.collectedObject = obj
+		r.collectedObject = obj
 	case errors.As(err, &errRemovedRemote):
-		exec.status = statusINHUMED
+		r.status = statusINHUMED
-		exec.err = errRemovedRemote
+		r.err = errRemovedRemote
 	case errors.As(err, &errRemovedLocal):
-		exec.status = statusINHUMED
+		r.status = statusINHUMED
-		exec.err = errRemovedLocal
+		r.err = errRemovedLocal
 	case errors.As(err, &errSplitInfo):
-		exec.status = statusVIRTUAL
+		r.status = statusVIRTUAL
-		exec.err = errSplitInfo
+		r.err = errSplitInfo
 	case errors.As(err, &errOutOfRangeRemote):
-		exec.status = statusOutOfRange
+		r.status = statusOutOfRange
-		exec.err = errOutOfRangeRemote
+		r.err = errOutOfRangeRemote
 	case errors.As(err, &errOutOfRangeLocal):
-		exec.status = statusOutOfRange
+		r.status = statusOutOfRange
-		exec.err = errOutOfRangeLocal
+		r.err = errOutOfRangeLocal
 	}
 }
 
@@ -96,42 +96,54 @@ func equalAddresses(a, b oid.Address) bool {
 	return a.Container().Equals(b.Container()) && a.Object().Equals(b.Object())
 }
 
-func (exec *execCtx) HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object, error) {
+func (r *request) HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object, error) {
-	p := exec.prm
-	p.common = p.common.WithLocalOnly(false)
-	p.addr.SetContainer(exec.containerID())
-	p.addr.SetObject(id)
-
-	prm := HeadPrm{
-		commonPrm: p.commonPrm,
-	}
-
 	w := NewSimpleObjectWriter()
-	prm.SetHeaderWriter(w)
-	err := exec.svc.Head(ctx, prm)
 
-	if err != nil {
+	p := RequestParameters{}
+	p.common = p.common.WithLocalOnly(false)
+	p.addr.SetContainer(r.containerID())
+	p.addr.SetObject(id)
+	p.head = true
+	p.SetHeaderWriter(w)
+
+	if err := r.getObjectWithIndependentRequest(ctx, p); err != nil {
 		return nil, err
 	}
 
 	return w.Object(), nil
 }
 
-func (exec *execCtx) GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range) (*objectSDK.Object, error) {
+func (r *request) GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range) (*objectSDK.Object, error) {
 	w := NewSimpleObjectWriter()
 
-	p := exec.prm
+	p := r.prm
 	p.common = p.common.WithLocalOnly(false)
 	p.objWriter = w
-	p.SetRange(rng)
+	p.rng = rng
 
-	p.addr.SetContainer(exec.containerID())
+	p.addr.SetContainer(r.containerID())
 	p.addr.SetObject(id)
 
-	statusError := exec.svc.get(ctx, p.commonPrm, withPayloadRange(rng))
+	if err := r.getObjectWithIndependentRequest(ctx, p); err != nil {
-
+		return nil, err
-	if statusError.err != nil {
-		return nil, statusError.err
 	}
 	return w.Object(), nil
 }
+
+func (r *request) getObjectWithIndependentRequest(ctx context.Context, prm RequestParameters) error {
+	detachedExecutor := &request{
+		keyStore:                 r.keyStore,
+		traverserGenerator:       r.traverserGenerator,
+		remoteStorageConstructor: r.remoteStorageConstructor,
+		epochSource:              r.epochSource,
+		localStorage:             r.localStorage,
+
+		prm:       prm,
+		infoSplit: objectSDK.NewSplitInfo(),
+		log:       r.log,
+	}
+
+	detachedExecutor.execute(ctx)
+
+	return detachedExecutor.statusError.err
+}

pkg/services/object/get/assembler.go

@@ -2,7 +2,6 @@ package getsvc
 
 import (
 	"context"
-	"errors"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/object"
 	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
@@ -15,10 +14,6 @@ type objectGetter interface {
 	HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object, error)
 }
 
-var (
-	errParentAddressDiffers = errors.New("parent address in child object differs")
-)
-
 type assembler struct {
 	addr      oid.Address
 	splitInfo *objectSDK.SplitInfo
@@ -89,7 +84,7 @@ func (a *assembler) initializeFromSourceObjectID(ctx context.Context, id oid.ID)
 
 	parentObject := sourceObject.Parent()
 	if parentObject == nil {
-		return nil, nil, errors.New("received child with empty parent")
+		return nil, nil, errChildWithEmptyParent
 	}
 
 	a.parentObject = parentObject

pkg/services/object/get/container.go

@@ -8,26 +8,26 @@ import (
 	"go.uber.org/zap"
 )
 
-func (exec *execCtx) executeOnContainer(ctx context.Context) {
+func (r *request) executeOnContainer(ctx context.Context) {
-	if exec.isLocal() {
+	if r.isLocal() {
-		exec.log.Debug(logs.GetReturnResultDirectly)
+		r.log.Debug(logs.GetReturnResultDirectly)
 		return
 	}
 
-	lookupDepth := exec.netmapLookupDepth()
+	lookupDepth := r.netmapLookupDepth()
 
-	exec.log.Debug(logs.TryingToExecuteInContainer,
+	r.log.Debug(logs.TryingToExecuteInContainer,
 		zap.Uint64("netmap lookup depth", lookupDepth),
 	)
 
 	// initialize epoch number
-	ok := exec.initEpoch()
+	ok := r.initEpoch()
 	if !ok {
 		return
 	}
 
 	for {
-		if exec.processCurrentEpoch(ctx) {
+		if r.processCurrentEpoch(ctx) {
 			break
 		}
 
@@ -39,16 +39,16 @@ func (exec *execCtx) executeOnContainer(ctx context.Context) {
 		lookupDepth--
 
 		// go to the previous epoch
-		exec.curProcEpoch--
+		r.curProcEpoch--
 	}
 }
 
-func (exec *execCtx) processCurrentEpoch(ctx context.Context) bool {
+func (r *request) processCurrentEpoch(ctx context.Context) bool {
-	exec.log.Debug(logs.ProcessEpoch,
+	r.log.Debug(logs.ProcessEpoch,
-		zap.Uint64("number", exec.curProcEpoch),
+		zap.Uint64("number", r.curProcEpoch),
 	)
 
-	traverser, ok := exec.generateTraverser(exec.address())
+	traverser, ok := r.generateTraverser(r.address())
 	if !ok {
 		return true
 	}
@@ -56,12 +56,12 @@ func (exec *execCtx) processCurrentEpoch(ctx context.Context) bool {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	exec.status = statusUndefined
+	r.status = statusUndefined
 
 	for {
 		addrs := traverser.Next()
 		if len(addrs) == 0 {
-			exec.log.Debug(logs.NoMoreNodesAbortPlacementIteration)
+			r.log.Debug(logs.NoMoreNodesAbortPlacementIteration)
 
 			return false
 		}
@@ -69,8 +69,8 @@ func (exec *execCtx) processCurrentEpoch(ctx context.Context) bool {
 		for i := range addrs {
 			select {
 			case <-ctx.Done():
-				exec.log.Debug(logs.InterruptPlacementIterationByContext,
+				r.log.Debug(logs.InterruptPlacementIterationByContext,
-					zap.String("error", ctx.Err().Error()),
+					zap.Error(ctx.Err()),
 				)
 
 				return true
@@ -84,8 +84,8 @@ func (exec *execCtx) processCurrentEpoch(ctx context.Context) bool {
 
 			client.NodeInfoFromNetmapElement(&info, addrs[i])
 
-			if exec.processNode(ctx, info) {
+			if r.processNode(ctx, info) {
-				exec.log.Debug(logs.GetCompletingTheOperation)
+				r.log.Debug(logs.GetCompletingTheOperation)
 				return true
 			}
 		}

pkg/services/object/get/errors.go

@@ -0,0 +1,10 @@
+package getsvc
+
+import "errors"
+
+var (
+	errRangeZeroLength      = errors.New("zero range length")
+	errRangeOverflow        = errors.New("range overflow")
+	errChildWithEmptyParent = errors.New("received child with empty parent")
+	errParentAddressDiffers = errors.New("parent address in child object differs")
+)

pkg/services/object/get/exec.go

@@ -1,279 +0,0 @@
-package getsvc
-
-import (
-	"context"
-	"crypto/ecdsa"
-
-	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
-	clientcore "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
-	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
-	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
-	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
-	"go.uber.org/zap"
-)
-
-type statusError struct {
-	status int
-	err    error
-}
-
-type execCtx struct {
-	svc *Service
-
-	prm RangePrm
-
-	statusError
-
-	infoSplit *objectSDK.SplitInfo
-
-	log *logger.Logger
-
-	collectedObject *objectSDK.Object
-
-	head bool
-
-	curProcEpoch uint64
-}
-
-type execOption func(*execCtx)
-
-const (
-	statusUndefined int = iota
-	statusOK
-	statusINHUMED
-	statusVIRTUAL
-	statusOutOfRange
-)
-
-func headOnly() execOption {
-	return func(c *execCtx) {
-		c.head = true
-	}
-}
-
-func withPayloadRange(r *objectSDK.Range) execOption {
-	return func(c *execCtx) {
-		c.prm.rng = r
-	}
-}
-
-func (exec *execCtx) setLogger(l *logger.Logger) {
-	req := "GET"
-	if exec.headOnly() {
-		req = "HEAD"
-	} else if exec.ctxRange() != nil {
-		req = "GET_RANGE"
-	}
-
-	exec.log = &logger.Logger{Logger: l.With(
-		zap.String("request", req),
-		zap.Stringer("address", exec.address()),
-		zap.Bool("raw", exec.isRaw()),
-		zap.Bool("local", exec.isLocal()),
-		zap.Bool("with session", exec.prm.common.SessionToken() != nil),
-		zap.Bool("with bearer", exec.prm.common.BearerToken() != nil),
-	)}
-}
-
-func (exec execCtx) isLocal() bool {
-	return exec.prm.common.LocalOnly()
-}
-
-func (exec execCtx) isRaw() bool {
-	return exec.prm.raw
-}
-
-func (exec execCtx) address() oid.Address {
-	return exec.prm.addr
-}
-
-func (exec execCtx) key() (*ecdsa.PrivateKey, error) {
-	if exec.prm.signerKey != nil {
-		// the key has already been requested and
-		// cached in the previous operations
-		return exec.prm.signerKey, nil
-	}
-
-	var sessionInfo *util.SessionInfo
-
-	if tok := exec.prm.common.SessionToken(); tok != nil {
-		sessionInfo = &util.SessionInfo{
-			ID:    tok.ID(),
-			Owner: tok.Issuer(),
-		}
-	}
-
-	return exec.svc.keyStore.GetKey(sessionInfo)
-}
-
-func (exec *execCtx) canAssemble() bool {
-	return !exec.isRaw() && !exec.headOnly()
-}
-
-func (exec *execCtx) splitInfo() *objectSDK.SplitInfo {
-	return exec.infoSplit
-}
-
-func (exec *execCtx) containerID() cid.ID {
-	return exec.address().Container()
-}
-
-func (exec *execCtx) ctxRange() *objectSDK.Range {
-	return exec.prm.rng
-}
-
-func (exec *execCtx) headOnly() bool {
-	return exec.head
-}
-
-func (exec *execCtx) netmapEpoch() uint64 {
-	return exec.prm.common.NetmapEpoch()
-}
-
-func (exec *execCtx) netmapLookupDepth() uint64 {
-	return exec.prm.common.NetmapLookupDepth()
-}
-
-func (exec *execCtx) initEpoch() bool {
-	exec.curProcEpoch = exec.netmapEpoch()
-	if exec.curProcEpoch > 0 {
-		return true
-	}
-
-	e, err := exec.svc.currentEpochReceiver.currentEpoch()
-
-	switch {
-	default:
-		exec.status = statusUndefined
-		exec.err = err
-
-		exec.log.Debug(logs.CouldNotGetCurrentEpochNumber,
-			zap.String("error", err.Error()),
-		)
-
-		return false
-	case err == nil:
-		exec.curProcEpoch = e
-		return true
-	}
-}
-
-func (exec *execCtx) generateTraverser(addr oid.Address) (*placement.Traverser, bool) {
-	obj := addr.Object()
-
-	t, err := exec.svc.traverserGenerator.GenerateTraverser(addr.Container(), &obj, exec.curProcEpoch)
-
-	switch {
-	default:
-		exec.status = statusUndefined
-		exec.err = err
-
-		exec.log.Debug(logs.GetCouldNotGenerateContainerTraverser,
-			zap.String("error", err.Error()),
-		)
-
-		return nil, false
-	case err == nil:
-		return t, true
-	}
-}
-
-func (exec execCtx) remoteClient(info clientcore.NodeInfo) (getClient, bool) {
-	c, err := exec.svc.clientCache.get(info)
-
-	switch {
-	default:
-		exec.status = statusUndefined
-		exec.err = err
-
-		exec.log.Debug(logs.GetCouldNotConstructRemoteNodeClient)
-	case err == nil:
-		return c, true
-	}
-
-	return nil, false
-}
-
-func mergeSplitInfo(dst, src *objectSDK.SplitInfo) {
-	if last, ok := src.LastPart(); ok {
-		dst.SetLastPart(last)
-	}
-
-	if link, ok := src.Link(); ok {
-		dst.SetLink(link)
-	}
-
-	if splitID := src.SplitID(); splitID != nil {
-		dst.SetSplitID(splitID)
-	}
-}
-
-func (exec *execCtx) writeCollectedHeader(ctx context.Context) bool {
-	if exec.ctxRange() != nil {
-		return true
-	}
-
-	err := exec.prm.objWriter.WriteHeader(
-		ctx,
-		exec.collectedObject.CutPayload(),
-	)
-
-	switch {
-	default:
-		exec.status = statusUndefined
-		exec.err = err
-
-		exec.log.Debug(logs.GetCouldNotWriteHeader,
-			zap.String("error", err.Error()),
-		)
-	case err == nil:
-		exec.status = statusOK
-		exec.err = nil
-	}
-
-	return exec.status == statusOK
-}
-
-func (exec *execCtx) writeObjectPayload(ctx context.Context, obj *objectSDK.Object) bool {
-	if exec.headOnly() {
-		return true
-	}
-
-	err := exec.prm.objWriter.WriteChunk(ctx, obj.Payload())
-
-	switch {
-	default:
-		exec.status = statusUndefined
-		exec.err = err
-
-		exec.log.Debug(logs.GetCouldNotWritePayloadChunk,
-			zap.String("error", err.Error()),
-		)
-	case err == nil:
-		exec.status = statusOK
-		exec.err = nil
-	}
-
-	return err == nil
-}
-
-func (exec *execCtx) writeCollectedObject(ctx context.Context) {
-	if ok := exec.writeCollectedHeader(ctx); ok {
-		exec.writeObjectPayload(ctx, exec.collectedObject)
-	}
-}
-
-// isForwardingEnabled returns true if common execution
-// parameters has request forwarding closure set.
-func (exec execCtx) isForwardingEnabled() bool {
-	return exec.prm.forwarder != nil
-}
-
-// disableForwarding removes request forwarding closure from common
-// parameters, so it won't be inherited in new execution contexts.
-func (exec *execCtx) disableForwarding() {
-	exec.prm.SetRequestForwarder(nil)
-}

pkg/services/object/get/get.go

@@ -11,18 +11,18 @@ import (
 
 // Get serves a request to get an object by address, and returns Streamer instance.
 func (s *Service) Get(ctx context.Context, prm Prm) error {
-	return s.get(ctx, prm.commonPrm).err
+	return s.get(ctx, RequestParameters{
+		commonPrm: prm.commonPrm,
+	})
 }
 
 // GetRange serves a request to get an object by address, and returns Streamer instance.
 func (s *Service) GetRange(ctx context.Context, prm RangePrm) error {
-	return s.getRange(ctx, prm)
+	return s.get(ctx, RequestParameters{
+		commonPrm: prm.commonPrm,
+		rng:       prm.rng,
+	})
 }
-
-func (s *Service) getRange(ctx context.Context, prm RangePrm, opts ...execOption) error {
-	return s.get(ctx, prm.commonPrm, append(opts, withPayloadRange(prm.rng))...).err
-}
-
 func (s *Service) GetRangeHash(ctx context.Context, prm RangeHashPrm) (*RangeHashRes, error) {
 	hashes := make([][]byte, 0, len(prm.rngs))
 
@@ -34,16 +34,15 @@ func (s *Service) GetRangeHash(ctx context.Context, prm RangeHashPrm) (*RangeHas
 		// 1. Potential gains are insignificant when operating in the Internet given typical latencies and losses.
 		// 2. Parallel solution is more complex in terms of code.
 		// 3. TZ-hash is likely to be disabled in private installations.
-		rngPrm := RangePrm{
+		reqPrm := RequestParameters{
 			commonPrm: prm.commonPrm,
+			rng:       &rng,
 		}
-
+		reqPrm.SetChunkWriter(&hasherWrapper{
-		rngPrm.SetRange(&rng)
-		rngPrm.SetChunkWriter(&hasherWrapper{
 			hash: util.NewSaltingWriter(h, prm.salt),
 		})
 
-		if err := s.getRange(ctx, rngPrm); err != nil {
+		if err := s.get(ctx, reqPrm); err != nil {
 			return nil, err
 		}
 
@@ -60,30 +59,32 @@ func (s *Service) GetRangeHash(ctx context.Context, prm RangeHashPrm) (*RangeHas
 // Returns ErrNotFound if the header was not received for the call.
 // Returns SplitInfoError if object is virtual and raw flag is set.
 func (s *Service) Head(ctx context.Context, prm HeadPrm) error {
-	return s.get(ctx, prm.commonPrm, headOnly()).err
+	return s.get(ctx, RequestParameters{
+		head:      true,
+		commonPrm: prm.commonPrm,
+	})
 }
 
-func (s *Service) get(ctx context.Context, prm commonPrm, opts ...execOption) statusError {
+func (s *Service) get(ctx context.Context, prm RequestParameters) error {
-	exec := &execCtx{
+	exec := &request{
-		svc: s,
+		keyStore:                 s.keyStore,
-		prm: RangePrm{
+		traverserGenerator:       s.traverserGenerator,
-			commonPrm: prm,
+		remoteStorageConstructor: s.remoteStorageConstructor,
-		},
+		epochSource:              s.epochSource,
-		infoSplit: object.NewSplitInfo(),
+		localStorage:             s.localStorage,
-	}
 
-	for i := range opts {
+		prm:       prm,
-		opts[i](exec)
+		infoSplit: object.NewSplitInfo(),
 	}
 
 	exec.setLogger(s.log)
 
 	exec.execute(ctx)
 
-	return exec.statusError
+	return exec.statusError.err
 }
 
-func (exec *execCtx) execute(ctx context.Context) {
+func (exec *request) execute(ctx context.Context) {
 	exec.log.Debug(logs.ServingRequest)
 
 	// perform local operation
@@ -92,7 +93,7 @@ func (exec *execCtx) execute(ctx context.Context) {
 	exec.analyzeStatus(ctx, true)
 }
 
-func (exec *execCtx) analyzeStatus(ctx context.Context, execCnr bool) {
+func (exec *request) analyzeStatus(ctx context.Context, execCnr bool) {
 	// analyze local result
 	switch exec.status {
 	case statusOK:
@@ -106,7 +107,7 @@ func (exec *execCtx) analyzeStatus(ctx context.Context, execCnr bool) {
 		exec.log.Debug(logs.GetRequestedRangeIsOutOfObjectBounds)
 	default:
 		exec.log.Debug(logs.OperationFinishedWithError,
-			zap.String("error", exec.err.Error()),
+			zap.Error(exec.err),
 		)
 
 		if execCnr {

pkg/services/object/get/get_test.go

@@ -2,6 +2,7 @@ package getsvc
 
 import (
 	"context"
+	"crypto/ecdsa"
 	"crypto/rand"
 	"errors"
 	"fmt"
@@ -56,7 +57,7 @@ type testClient struct {
 
 type testEpochReceiver uint64
 
-func (e testEpochReceiver) currentEpoch() (uint64, error) {
+func (e testEpochReceiver) Epoch() (uint64, error) {
 	return uint64(e), nil
 }
 
@@ -99,7 +100,7 @@ func (p *testPlacementBuilder) BuildPlacement(cnr cid.ID, obj *oid.ID, _ netmap.
 	return vs, nil
 }
 
-func (c *testClientCache) get(info client.NodeInfo) (getClient, error) {
+func (c *testClientCache) Get(info client.NodeInfo) (remoteStorage, error) {
 	v, ok := c.clients[network.StringifyGroup(info.AddressGroup())]
 	if !ok {
 		return nil, errors.New("could not construct client")
@@ -117,8 +118,15 @@ func newTestClient() *testClient {
 	}
 }
 
-func (c *testClient) getObject(ctx context.Context, exec *execCtx, _ client.NodeInfo) (*objectSDK.Object, error) {
+func (c *testClient) addResult(addr oid.Address, obj *objectSDK.Object, err error) {
-	v, ok := c.results[exec.address().EncodeToString()]
+	c.results[addr.EncodeToString()] = struct {
+		obj *objectSDK.Object
+		err error
+	}{obj: obj, err: err}
+}
+
+func (c *testClient) Get(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
+	v, ok := c.results[address.EncodeToString()]
 	if !ok {
 		var errNotFound apistatus.ObjectNotFound
 
@@ -129,21 +137,38 @@ func (c *testClient) getObject(ctx context.Context, exec *execCtx, _ client.Node
 		return nil, v.err
 	}
 
-	return cutToRange(v.obj, exec.ctxRange()), nil
+	return v.obj, nil
 }
 
-func (c *testClient) addResult(addr oid.Address, obj *objectSDK.Object, err error) {
+func (c *testClient) Head(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
-	c.results[addr.EncodeToString()] = struct {
+	return c.Get(ctx, address, requestParams)
-		obj *objectSDK.Object
-		err error
-	}{obj: obj, err: err}
 }
 
-func (s *testStorage) get(_ context.Context, exec *execCtx) (*objectSDK.Object, error) {
+func (c *testClient) Range(ctx context.Context, address oid.Address, rng *objectSDK.Range, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
+	obj, err := c.Get(ctx, address, requestParams)
+	if err != nil {
+		return nil, err
+	}
+	return cutToRange(obj, rng), nil
+}
+
+func (c *testClient) ForwardRequest(ctx context.Context, info client.NodeInfo, forwarder RequestForwarder) (*objectSDK.Object, error) {
+	return nil, fmt.Errorf("not implemented")
+}
+
+func (s *testStorage) Get(ctx context.Context, address oid.Address) (*objectSDK.Object, error) {
+	return s.Range(ctx, address, nil)
+}
+
+func (s *testStorage) Head(ctx context.Context, address oid.Address, isRaw bool) (*objectSDK.Object, error) {
+	return s.Range(ctx, address, nil)
+}
+
+func (s *testStorage) Range(_ context.Context, address oid.Address, rng *objectSDK.Range) (*objectSDK.Object, error) {
 	var (
 		ok    bool
 		obj   *objectSDK.Object
-		sAddr = exec.address().EncodeToString()
+		sAddr = address.EncodeToString()
 	)
 
 	if _, ok = s.inhumed[sAddr]; ok {
@@ -157,7 +182,7 @@ func (s *testStorage) get(_ context.Context, exec *execCtx) (*objectSDK.Object,
 	}
 
 	if obj, ok = s.phy[sAddr]; ok {
-		return cutToRange(obj, exec.ctxRange()), nil
+		return cutToRange(obj, rng), nil
 	}
 
 	var errNotFound apistatus.ObjectNotFound
@@ -241,15 +266,21 @@ func (w *writePayloadErrorObjectWriter) WriteChunk(_ context.Context, _ []byte)
 	return &writePayloadError{}
 }
 
+type testKeyStorage struct {
+}
+
+func (ks *testKeyStorage) GetKey(_ *util.SessionInfo) (*ecdsa.PrivateKey, error) {
+	return &ecdsa.PrivateKey{}, nil
+}
+
 func TestGetLocalOnly(t *testing.T) {
 	ctx := context.Background()
 
 	newSvc := func(storage *testStorage) *Service {
-		svc := &Service{cfg: new(cfg)}
+		return &Service{
-		svc.log = test.NewLogger(t, false)
+			log:          test.NewLogger(t, false),
-		svc.localStorage = storage
+			localStorage: storage,
-
+		}
-		return svc
 	}
 
 	newPrm := func(raw bool, w ObjectWriter) Prm {
@@ -506,22 +537,21 @@ func TestGetRemoteSmall(t *testing.T) {
 	container.CalculateID(&idCnr, cnr)
 
 	newSvc := func(b *testPlacementBuilder, c *testClientCache) *Service {
-		svc := &Service{cfg: new(cfg)}
-		svc.log = test.NewLogger(t, false)
-		svc.localStorage = newTestStorage()
-
 		const curEpoch = 13
 
-		svc.traverserGenerator = &testTraverserGenerator{
+		return &Service{
-			c: cnr,
+			log:          test.NewLogger(t, false),
-			b: map[uint64]placement.Builder{
+			localStorage: newTestStorage(),
-				curEpoch: b,
+			traverserGenerator: &testTraverserGenerator{
+				c: cnr,
+				b: map[uint64]placement.Builder{
+					curEpoch: b,
+				},
 			},
+			epochSource:              testEpochReceiver(curEpoch),
+			remoteStorageConstructor: c,
+			keyStore:                 &testKeyStorage{},
 		}
-		svc.clientCache = c
-		svc.currentEpochReceiver = testEpochReceiver(curEpoch)
-
-		return svc
 	}
 
 	newPrm := func(raw bool, w ObjectWriter) Prm {
@@ -1176,7 +1206,7 @@ func TestGetRemoteSmall(t *testing.T) {
 
 				err := svc.Get(ctx, p)
 				require.Error(t, err)
-				require.Equal(t, err.Error(), "received child with empty parent")
+				require.ErrorIs(t, err, errChildWithEmptyParent)
 
 				w = NewSimpleObjectWriter()
 				payloadSz := srcObj.PayloadSize()
@@ -1189,7 +1219,7 @@ func TestGetRemoteSmall(t *testing.T) {
 
 				err = svc.GetRange(ctx, rngPrm)
 				require.Error(t, err)
-				require.Equal(t, err.Error(), "received child with empty parent")
+				require.ErrorIs(t, err, errChildWithEmptyParent)
 			})
 
 			t.Run("out of range", func(t *testing.T) {
@@ -1639,39 +1669,38 @@ func TestGetFromPastEpoch(t *testing.T) {
 	c22 := newTestClient()
 	c22.addResult(addr, obj, nil)
 
-	svc := &Service{cfg: new(cfg)}
-	svc.log = test.NewLogger(t, false)
-	svc.localStorage = newTestStorage()
-
 	const curEpoch = 13
 
-	svc.traverserGenerator = &testTraverserGenerator{
+	svc := &Service{
-		c: cnr,
+		log:          test.NewLogger(t, false),
-		b: map[uint64]placement.Builder{
+		localStorage: newTestStorage(),
-			curEpoch: &testPlacementBuilder{
+		epochSource:  testEpochReceiver(curEpoch),
-				vectors: map[string][][]netmap.NodeInfo{
+		traverserGenerator: &testTraverserGenerator{
-					addr.EncodeToString(): ns[:1],
+			c: cnr,
+			b: map[uint64]placement.Builder{
+				curEpoch: &testPlacementBuilder{
+					vectors: map[string][][]netmap.NodeInfo{
+						addr.EncodeToString(): ns[:1],
+					},
 				},
-			},
+				curEpoch - 1: &testPlacementBuilder{
-			curEpoch - 1: &testPlacementBuilder{
+					vectors: map[string][][]netmap.NodeInfo{
-				vectors: map[string][][]netmap.NodeInfo{
+						addr.EncodeToString(): ns[1:],
-					addr.EncodeToString(): ns[1:],
+					},
 				},
 			},
 		},
-	}
+		remoteStorageConstructor: &testClientCache{
-
+			clients: map[string]*testClient{
-	svc.clientCache = &testClientCache{
+				as[0][0]: c11,
-		clients: map[string]*testClient{
+				as[0][1]: c12,
-			as[0][0]: c11,
+				as[1][0]: c21,
-			as[0][1]: c12,
+				as[1][1]: c22,
-			as[1][0]: c21,
+			},
-			as[1][1]: c22,
 		},
+		keyStore: &testKeyStorage{},
 	}
 
-	svc.currentEpochReceiver = testEpochReceiver(curEpoch)
-
 	w := NewSimpleObjectWriter()
 
 	commonPrm := new(util.CommonPrm)

pkg/services/object/get/local.go

@@ -11,7 +11,7 @@ import (
 	"go.uber.org/zap"
 )
 
-func (exec *execCtx) executeLocal(ctx context.Context) {
+func (r *request) executeLocal(ctx context.Context) {
 	ctx, span := tracing.StartSpanFromContext(ctx, "getService.executeLocal")
 	defer func() {
 		span.End()
@@ -19,7 +19,7 @@ func (exec *execCtx) executeLocal(ctx context.Context) {
 
 	var err error
 
-	exec.collectedObject, err = exec.svc.localStorage.get(ctx, exec)
+	r.collectedObject, err = r.get(ctx)
 
 	var errSplitInfo *objectSDK.SplitInfoError
 	var errRemoved apistatus.ObjectAlreadyRemoved
@@ -27,25 +27,33 @@ func (exec *execCtx) executeLocal(ctx context.Context) {
 
 	switch {
 	default:
-		exec.status = statusUndefined
+		r.status = statusUndefined
-		exec.err = err
+		r.err = err
 
-		exec.log.Debug(logs.GetLocalGetFailed,
+		r.log.Debug(logs.GetLocalGetFailed, zap.Error(err))
-			zap.String("error", err.Error()),
-		)
 	case err == nil:
-		exec.status = statusOK
+		r.status = statusOK
-		exec.err = nil
+		r.err = nil
-		exec.writeCollectedObject(ctx)
+		r.writeCollectedObject(ctx)
 	case errors.As(err, &errRemoved):
-		exec.status = statusINHUMED
+		r.status = statusINHUMED
-		exec.err = errRemoved
+		r.err = errRemoved
 	case errors.As(err, &errSplitInfo):
-		exec.status = statusVIRTUAL
+		r.status = statusVIRTUAL
-		mergeSplitInfo(exec.splitInfo(), errSplitInfo.SplitInfo())
+		mergeSplitInfo(r.splitInfo(), errSplitInfo.SplitInfo())
-		exec.err = objectSDK.NewSplitInfoError(exec.infoSplit)
+		r.err = objectSDK.NewSplitInfoError(r.infoSplit)
 	case errors.As(err, &errOutOfRange):
-		exec.status = statusOutOfRange
+		r.status = statusOutOfRange
-		exec.err = errOutOfRange
+		r.err = errOutOfRange
 	}
 }
+
+func (r *request) get(ctx context.Context) (*objectSDK.Object, error) {
+	if r.headOnly() {
+		return r.localStorage.Head(ctx, r.address(), r.isRaw())
+	}
+	if rng := r.ctxRange(); rng != nil {
+		return r.localStorage.Range(ctx, r.address(), rng)
+	}
+	return r.localStorage.Get(ctx, r.address())
+}

pkg/services/object/get/prm.go

@@ -3,12 +3,11 @@ package getsvc
 import (
 	"context"
 	"crypto/ecdsa"
-	"errors"
 	"hash"
 
 	coreclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
-	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 )
 
@@ -21,14 +20,9 @@ type Prm struct {
 type RangePrm struct {
 	commonPrm
 
-	rng *object.Range
+	rng *objectSDK.Range
 }
 
-var (
-	errRangeZeroLength = errors.New("zero range length")
-	errRangeOverflow   = errors.New("range overflow")
-)
-
 // Validate pre-validates `OBJECTRANGE` request's parameters content
 // without access to the requested object's payload.
 func (p RangePrm) Validate() error {
@@ -54,12 +48,18 @@ type RangeHashPrm struct {
 
 	hashGen func() hash.Hash
 
-	rngs []object.Range
+	rngs []objectSDK.Range
 
 	salt []byte
 }
 
-type RequestForwarder func(context.Context, coreclient.NodeInfo, coreclient.MultiAddressClient) (*object.Object, error)
+type RequestParameters struct {
+	commonPrm
+	head bool
+	rng  *objectSDK.Range
+}
+
+type RequestForwarder func(context.Context, coreclient.NodeInfo, coreclient.MultiAddressClient) (*objectSDK.Object, error)
 
 // HeadPrm groups parameters of Head service call.
 type HeadPrm struct {
@@ -83,43 +83,25 @@ type commonPrm struct {
 	signerKey *ecdsa.PrivateKey
 }
 
-// ChunkWriter is an interface of target component
-// to write payload chunk.
-type ChunkWriter interface {
-	WriteChunk(context.Context, []byte) error
-}
-
-// HeaderWriter is an interface of target component
-// to write object header.
-type HeaderWriter interface {
-	WriteHeader(context.Context, *object.Object) error
-}
-
-// ObjectWriter is an interface of target component to write object.
-type ObjectWriter interface {
-	HeaderWriter
-	ChunkWriter
-}
-
 // SetObjectWriter sets target component to write the object.
 func (p *Prm) SetObjectWriter(w ObjectWriter) {
 	p.objWriter = w
 }
 
 // SetChunkWriter sets target component to write the object payload range.
-func (p *RangePrm) SetChunkWriter(w ChunkWriter) {
+func (p *commonPrm) SetChunkWriter(w ChunkWriter) {
 	p.objWriter = &partWriter{
 		chunkWriter: w,
 	}
 }
 
 // SetRange sets range of the requested payload data.
-func (p *RangePrm) SetRange(rng *object.Range) {
+func (p *RangePrm) SetRange(rng *objectSDK.Range) {
 	p.rng = rng
 }
 
 // SetRangeList sets a list of object payload ranges.
-func (p *RangeHashPrm) SetRangeList(rngs []object.Range) {
+func (p *RangeHashPrm) SetRangeList(rngs []objectSDK.Range) {
 	p.rngs = rngs
 }
 
@@ -158,7 +140,7 @@ func (p *commonPrm) WithCachedSignerKey(signerKey *ecdsa.PrivateKey) {
 }
 
 // SetHeaderWriter sets target component to write the object header.
-func (p *HeadPrm) SetHeaderWriter(w HeaderWriter) {
+func (p *commonPrm) SetHeaderWriter(w HeaderWriter) {
 	p.objWriter = &partWriter{
 		headWriter: w,
 	}

pkg/services/object/get/remote.go

@@ -12,18 +12,18 @@ import (
 	"go.uber.org/zap"
 )
 
-func (exec *execCtx) processNode(ctx context.Context, info client.NodeInfo) bool {
+func (r *request) processNode(ctx context.Context, info client.NodeInfo) bool {
 	ctx, span := tracing.StartSpanFromContext(ctx, "getService.processNode")
 	defer span.End()
 
-	exec.log.Debug(logs.ProcessingNode)
+	r.log.Debug(logs.ProcessingNode)
 
-	client, ok := exec.remoteClient(info)
+	rs, ok := r.getRemoteStorage(info)
 	if !ok {
 		return true
 	}
 
-	obj, err := client.getObject(ctx, exec, info)
+	obj, err := r.getRemote(ctx, rs, info)
 
 	var errSplitInfo *objectSDK.SplitInfoError
 	var errRemoved *apistatus.ObjectAlreadyRemoved
@@ -33,34 +33,66 @@ func (exec *execCtx) processNode(ctx context.Context, info client.NodeInfo) bool
 	default:
 		var errNotFound apistatus.ObjectNotFound
 
-		exec.status = statusUndefined
+		r.status = statusUndefined
-		exec.err = errNotFound
+		r.err = errNotFound
 
-		exec.log.Debug(logs.GetRemoteCallFailed,
+		r.log.Debug(logs.GetRemoteCallFailed, zap.Error(err))
-			zap.String("error", err.Error()),
-		)
 	case err == nil:
-		exec.status = statusOK
+		r.status = statusOK
-		exec.err = nil
+		r.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
+			r.collectedObject = obj
-			exec.writeCollectedObject(ctx)
+			r.writeCollectedObject(ctx)
 		}
 	case errors.As(err, &errRemoved):
-		exec.status = statusINHUMED
+		r.status = statusINHUMED
-		exec.err = errRemoved
+		r.err = errRemoved
 	case errors.As(err, &errOutOfRange):
-		exec.status = statusOutOfRange
+		r.status = statusOutOfRange
-		exec.err = errOutOfRange
+		r.err = errOutOfRange
 	case errors.As(err, &errSplitInfo):
-		exec.status = statusVIRTUAL
+		r.status = statusVIRTUAL
-		mergeSplitInfo(exec.splitInfo(), errSplitInfo.SplitInfo())
+		mergeSplitInfo(r.splitInfo(), errSplitInfo.SplitInfo())
-		exec.err = objectSDK.NewSplitInfoError(exec.infoSplit)
+		r.err = objectSDK.NewSplitInfoError(r.infoSplit)
 	}
 
-	return exec.status != statusUndefined
+	return r.status != statusUndefined
+}
+
+func (r *request) getRemote(ctx context.Context, rs remoteStorage, info client.NodeInfo) (*objectSDK.Object, error) {
+	if r.isForwardingEnabled() {
+		return rs.ForwardRequest(ctx, info, r.prm.forwarder)
+	}
+
+	key, err := r.key()
+	if err != nil {
+		return nil, err
+	}
+
+	prm := RemoteRequestParams{
+		Epoch:        r.curProcEpoch,
+		TTL:          r.prm.common.TTL(),
+		PrivateKey:   key,
+		SessionToken: r.prm.common.SessionToken(),
+		BearerToken:  r.prm.common.BearerToken(),
+		XHeaders:     r.prm.common.XHeaders(),
+		IsRaw:        r.isRaw(),
+	}
+
+	if r.headOnly() {
+		return rs.Head(ctx, r.address(), prm)
+	}
+	// we don't specify payload writer because we accumulate
+	// the object locally (even huge).
+	if rng := r.ctxRange(); rng != nil {
+		// Current spec allows other storage node to deny access,
+		// fallback to GET here.
+		return rs.Range(ctx, r.address(), rng, prm)
+	}
+
+	return rs.Get(ctx, r.address(), prm)
 }

pkg/services/object/get/request.go

@@ -0,0 +1,244 @@
+package getsvc
+
+import (
+	"context"
+	"crypto/ecdsa"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
+	clientcore "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
+	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	"go.uber.org/zap"
+)
+
+type request struct {
+	prm RequestParameters
+
+	statusError
+
+	infoSplit *objectSDK.SplitInfo
+
+	log *logger.Logger
+
+	collectedObject *objectSDK.Object
+
+	curProcEpoch uint64
+
+	keyStore                 keyStorage
+	epochSource              epochSource
+	traverserGenerator       traverserGenerator
+	remoteStorageConstructor remoteStorageConstructor
+	localStorage             localStorage
+}
+
+func (r *request) setLogger(l *logger.Logger) {
+	req := "GET"
+	if r.headOnly() {
+		req = "HEAD"
+	} else if r.ctxRange() != nil {
+		req = "GET_RANGE"
+	}
+
+	r.log = &logger.Logger{Logger: l.With(
+		zap.String("request", req),
+		zap.Stringer("address", r.address()),
+		zap.Bool("raw", r.isRaw()),
+		zap.Bool("local", r.isLocal()),
+		zap.Bool("with session", r.prm.common.SessionToken() != nil),
+		zap.Bool("with bearer", r.prm.common.BearerToken() != nil),
+	)}
+}
+
+func (r *request) isLocal() bool {
+	return r.prm.common.LocalOnly()
+}
+
+func (r *request) isRaw() bool {
+	return r.prm.raw
+}
+
+func (r *request) address() oid.Address {
+	return r.prm.addr
+}
+
+func (r *request) key() (*ecdsa.PrivateKey, error) {
+	if r.prm.signerKey != nil {
+		// the key has already been requested and
+		// cached in the previous operations
+		return r.prm.signerKey, nil
+	}
+
+	var sessionInfo *util.SessionInfo
+
+	if tok := r.prm.common.SessionToken(); tok != nil {
+		sessionInfo = &util.SessionInfo{
+			ID:    tok.ID(),
+			Owner: tok.Issuer(),
+		}
+	}
+
+	return r.keyStore.GetKey(sessionInfo)
+}
+
+func (r *request) canAssemble() bool {
+	return !r.isRaw() && !r.headOnly()
+}
+
+func (r *request) splitInfo() *objectSDK.SplitInfo {
+	return r.infoSplit
+}
+
+func (r *request) containerID() cid.ID {
+	return r.address().Container()
+}
+
+func (r *request) ctxRange() *objectSDK.Range {
+	return r.prm.rng
+}
+
+func (r *request) headOnly() bool {
+	return r.prm.head
+}
+
+func (r *request) netmapEpoch() uint64 {
+	return r.prm.common.NetmapEpoch()
+}
+
+func (r *request) netmapLookupDepth() uint64 {
+	return r.prm.common.NetmapLookupDepth()
+}
+
+func (r *request) initEpoch() bool {
+	r.curProcEpoch = r.netmapEpoch()
+	if r.curProcEpoch > 0 {
+		return true
+	}
+
+	e, err := r.epochSource.Epoch()
+
+	switch {
+	default:
+		r.status = statusUndefined
+		r.err = err
+
+		r.log.Debug(logs.CouldNotGetCurrentEpochNumber, zap.Error(err))
+
+		return false
+	case err == nil:
+		r.curProcEpoch = e
+		return true
+	}
+}
+
+func (r *request) generateTraverser(addr oid.Address) (*placement.Traverser, bool) {
+	obj := addr.Object()
+
+	t, err := r.traverserGenerator.GenerateTraverser(addr.Container(), &obj, r.curProcEpoch)
+
+	switch {
+	default:
+		r.status = statusUndefined
+		r.err = err
+
+		r.log.Debug(logs.GetCouldNotGenerateContainerTraverser, zap.Error(err))
+
+		return nil, false
+	case err == nil:
+		return t, true
+	}
+}
+
+func (r *request) getRemoteStorage(info clientcore.NodeInfo) (remoteStorage, bool) {
+	rs, err := r.remoteStorageConstructor.Get(info)
+	if err != nil {
+		r.status = statusUndefined
+		r.err = err
+
+		r.log.Debug(logs.GetCouldNotConstructRemoteNodeClient)
+
+		return nil, false
+	}
+
+	return rs, true
+}
+
+func (r *request) writeCollectedHeader(ctx context.Context) bool {
+	if r.ctxRange() != nil {
+		return true
+	}
+
+	err := r.prm.objWriter.WriteHeader(
+		ctx,
+		r.collectedObject.CutPayload(),
+	)
+
+	switch {
+	default:
+		r.status = statusUndefined
+		r.err = err
+
+		r.log.Debug(logs.GetCouldNotWriteHeader, zap.Error(err))
+	case err == nil:
+		r.status = statusOK
+		r.err = nil
+	}
+
+	return r.status == statusOK
+}
+
+func (r *request) writeObjectPayload(ctx context.Context, obj *objectSDK.Object) bool {
+	if r.headOnly() {
+		return true
+	}
+
+	err := r.prm.objWriter.WriteChunk(ctx, obj.Payload())
+
+	switch {
+	default:
+		r.status = statusUndefined
+		r.err = err
+
+		r.log.Debug(logs.GetCouldNotWritePayloadChunk, zap.Error(err))
+	case err == nil:
+		r.status = statusOK
+		r.err = nil
+	}
+
+	return err == nil
+}
+
+func (r *request) writeCollectedObject(ctx context.Context) {
+	if ok := r.writeCollectedHeader(ctx); ok {
+		r.writeObjectPayload(ctx, r.collectedObject)
+	}
+}
+
+// isForwardingEnabled returns true if common execution
+// parameters has request forwarding closure set.
+func (r request) isForwardingEnabled() bool {
+	return r.prm.forwarder != nil
+}
+
+// disableForwarding removes request forwarding closure from common
+// parameters, so it won't be inherited in new execution contexts.
+func (r *request) disableForwarding() {
+	r.prm.SetRequestForwarder(nil)
+}
+
+func mergeSplitInfo(dst, src *objectSDK.SplitInfo) {
+	if last, ok := src.LastPart(); ok {
+		dst.SetLastPart(last)
+	}
+
+	if link, ok := src.Link(); ok {
+		dst.SetLink(link)
+	}
+
+	if splitID := src.SplitID(); splitID != nil {
+		dst.SetSplitID(splitID)
+	}
+}

pkg/services/object/get/res.go

@@ -1,9 +0,0 @@
-package getsvc
-
-type RangeHashRes struct {
-	hashes [][]byte
-}
-
-func (r *RangeHashRes) Hashes() [][]byte {
-	return r.hashes
-}

pkg/services/object/get/service.go

@@ -1,124 +1,54 @@
 package getsvc
 
 import (
-	"context"
-
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/netmap"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
-	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
-	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
-	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 	"go.uber.org/zap"
 )
 
+// Option is a Service's constructor option.
+type Option func(*Service)
+
 // Service utility serving requests of Object.Get service.
 type Service struct {
-	*cfg
+	log                      *logger.Logger
-}
+	localStorage             localStorage
-
+	traverserGenerator       traverserGenerator
-// Option is a Service's constructor option.
+	epochSource              epochSource
-type Option func(*cfg)
+	keyStore                 keyStorage
-
+	remoteStorageConstructor remoteStorageConstructor
-type getClient interface {
-	getObject(context.Context, *execCtx, client.NodeInfo) (*object.Object, error)
-}
-
-type cfg struct {
-	log *logger.Logger
-
-	localStorage interface {
-		get(context.Context, *execCtx) (*object.Object, error)
-	}
-
-	clientCache interface {
-		get(client.NodeInfo) (getClient, error)
-	}
-
-	traverserGenerator interface {
-		GenerateTraverser(cid.ID, *oid.ID, uint64) (*placement.Traverser, error)
-	}
-
-	currentEpochReceiver interface {
-		currentEpoch() (uint64, error)
-	}
-
-	keyStore *util.KeyStorage
-}
-
-func defaultCfg() *cfg {
-	return &cfg{
-		log:          &logger.Logger{Logger: zap.L()},
-		localStorage: new(storageEngineWrapper),
-		clientCache:  new(clientCacheWrapper),
-	}
 }
 
 // New creates, initializes and returns utility serving
 // Object.Get service requests.
-func New(opts ...Option) *Service {
+func New(
-	c := defaultCfg()
+	ks keyStorage,
-
+	es epochSource,
-	for i := range opts {
+	e localStorageEngine,
-		opts[i](c)
+	tg traverserGenerator,
+	cc clientConstructor,
+	opts ...Option,
+) *Service {
+	result := &Service{
+		keyStore:    ks,
+		epochSource: es,
+		log:         &logger.Logger{Logger: zap.L()},
+		localStorage: &engineLocalStorage{
+			engine: e,
+		},
+		traverserGenerator: tg,
+		remoteStorageConstructor: &multiclientRemoteStorageConstructor{
+			clientConstructor: cc,
+		},
 	}
-
+	for _, option := range opts {
-	return &Service{
+		option(result)
-		cfg: c,
 	}
+	return result
 }
 
 // WithLogger returns option to specify Get service's logger.
 func WithLogger(l *logger.Logger) Option {
-	return func(c *cfg) {
+	return func(s *Service) {
-		c.log = &logger.Logger{Logger: l.With(zap.String("component", "Object.Get service"))}
+		s.log = &logger.Logger{Logger: l.With(zap.String("component", "Object.Get service"))}
-	}
-}
-
-// WithLocalStorageEngine returns option to set local storage
-// instance.
-func WithLocalStorageEngine(e *engine.StorageEngine) Option {
-	return func(c *cfg) {
-		c.localStorage.(*storageEngineWrapper).engine = e
-	}
-}
-
-type ClientConstructor interface {
-	Get(client.NodeInfo) (client.MultiAddressClient, error)
-}
-
-// WithClientConstructor returns option to set constructor of remote node clients.
-func WithClientConstructor(v ClientConstructor) Option {
-	return func(c *cfg) {
-		c.clientCache.(*clientCacheWrapper).cache = v
-	}
-}
-
-// WithTraverserGenerator returns option to set generator of
-// placement traverser to get the objects from containers.
-func WithTraverserGenerator(t *util.TraverserGenerator) Option {
-	return func(c *cfg) {
-		c.traverserGenerator = t
-	}
-}
-
-// WithNetMapSource returns option to set network
-// map storage to receive current network state.
-func WithNetMapSource(nmSrc netmap.Source) Option {
-	return func(c *cfg) {
-		c.currentEpochReceiver = &nmSrcWrapper{
-			nmSrc: nmSrc,
-		}
-	}
-}
-
-// WithKeyStorage returns option to set private
-// key storage for session tokens and node key.
-func WithKeyStorage(store *util.KeyStorage) Option {
-	return func(c *cfg) {
-		c.keyStore = store
 	}
 }

pkg/services/object/get/status.go

@@ -0,0 +1,14 @@
+package getsvc
+
+const (
+	statusUndefined int = iota
+	statusOK
+	statusINHUMED
+	statusVIRTUAL
+	statusOutOfRange
+)
+
+type statusError struct {
+	status int
+	err    error
+}

pkg/services/object/get/types.go

@@ -0,0 +1,238 @@
+package getsvc
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"errors"
+
+	coreclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine"
+	internalclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/internal/client"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/bearer"
+	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
+	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/session"
+)
+
+type epochSource interface {
+	Epoch() (uint64, error)
+}
+
+type traverserGenerator interface {
+	GenerateTraverser(cid.ID, *oid.ID, uint64) (*placement.Traverser, error)
+}
+
+type keyStorage interface {
+	GetKey(info *util.SessionInfo) (*ecdsa.PrivateKey, error)
+}
+
+type localStorageEngine interface {
+	Head(ctx context.Context, p engine.HeadPrm) (engine.HeadRes, error)
+	GetRange(ctx context.Context, p engine.RngPrm) (engine.RngRes, error)
+	Get(ctx context.Context, p engine.GetPrm) (engine.GetRes, error)
+}
+
+type clientConstructor interface {
+	Get(coreclient.NodeInfo) (coreclient.MultiAddressClient, error)
+}
+
+type remoteStorageConstructor interface {
+	Get(coreclient.NodeInfo) (remoteStorage, error)
+}
+
+type multiclientRemoteStorageConstructor struct {
+	clientConstructor clientConstructor
+}
+
+func (c *multiclientRemoteStorageConstructor) Get(info coreclient.NodeInfo) (remoteStorage, error) {
+	clt, err := c.clientConstructor.Get(info)
+	if err != nil {
+		return nil, err
+	}
+
+	return &multiaddressRemoteStorage{
+		client: clt,
+	}, nil
+}
+
+type localStorage interface {
+	Head(ctx context.Context, address oid.Address, isRaw bool) (*objectSDK.Object, error)
+	Range(ctx context.Context, address oid.Address, rng *objectSDK.Range) (*objectSDK.Object, error)
+	Get(ctx context.Context, address oid.Address) (*objectSDK.Object, error)
+}
+
+type engineLocalStorage struct {
+	engine localStorageEngine
+}
+
+func (s *engineLocalStorage) Head(ctx context.Context, address oid.Address, isRaw bool) (*objectSDK.Object, error) {
+	var headPrm engine.HeadPrm
+	headPrm.WithAddress(address)
+	headPrm.WithRaw(isRaw)
+
+	r, err := s.engine.Head(ctx, headPrm)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Header(), nil
+}
+
+func (s *engineLocalStorage) Range(ctx context.Context, address oid.Address, rng *objectSDK.Range) (*objectSDK.Object, error) {
+	var getRange engine.RngPrm
+	getRange.WithAddress(address)
+	getRange.WithPayloadRange(rng)
+
+	r, err := s.engine.GetRange(ctx, getRange)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Object(), nil
+}
+
+func (s *engineLocalStorage) Get(ctx context.Context, address oid.Address) (*objectSDK.Object, error) {
+	var getPrm engine.GetPrm
+	getPrm.WithAddress(address)
+
+	r, err := s.engine.Get(ctx, getPrm)
+	if err != nil {
+		return nil, err
+	}
+
+	return r.Object(), nil
+}
+
+type RemoteRequestParams struct {
+	Epoch        uint64
+	TTL          uint32
+	PrivateKey   *ecdsa.PrivateKey
+	SessionToken *session.Object
+	BearerToken  *bearer.Token
+	XHeaders     []string
+	IsRaw        bool
+}
+
+type remoteStorage interface {
+	Get(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error)
+	Head(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error)
+	Range(ctx context.Context, address oid.Address, rng *objectSDK.Range, requestParams RemoteRequestParams) (*objectSDK.Object, error)
+
+	ForwardRequest(ctx context.Context, info coreclient.NodeInfo, forwarder RequestForwarder) (*objectSDK.Object, error)
+}
+
+type multiaddressRemoteStorage struct {
+	client coreclient.MultiAddressClient
+}
+
+func (s *multiaddressRemoteStorage) ForwardRequest(ctx context.Context, info coreclient.NodeInfo, forwarder RequestForwarder) (*objectSDK.Object, error) {
+	return forwarder(ctx, info, s.client)
+}
+
+func (s *multiaddressRemoteStorage) Range(ctx context.Context, address oid.Address, rng *objectSDK.Range, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
+	var prm internalclient.PayloadRangePrm
+
+	prm.SetClient(s.client)
+	prm.SetTTL(requestParams.TTL)
+	prm.SetNetmapEpoch(requestParams.Epoch)
+	prm.SetAddress(address)
+	prm.SetPrivateKey(requestParams.PrivateKey)
+	prm.SetSessionToken(requestParams.SessionToken)
+	prm.SetBearerToken(requestParams.BearerToken)
+	prm.SetXHeaders(requestParams.XHeaders)
+	prm.SetRange(rng)
+	if requestParams.IsRaw {
+		prm.SetRawFlag()
+	}
+
+	res, err := internalclient.PayloadRange(ctx, prm)
+	if err != nil {
+		var errAccessDenied *apistatus.ObjectAccessDenied
+		if errors.As(err, &errAccessDenied) {
+			obj, err := s.Get(ctx, address, requestParams)
+			if err != nil {
+				return nil, err
+			}
+
+			payload := obj.Payload()
+			from := rng.GetOffset()
+			to := from + rng.GetLength()
+
+			if pLen := uint64(len(payload)); to < from || pLen < from || pLen < to {
+				return nil, new(apistatus.ObjectOutOfRange)
+			}
+
+			return s.payloadOnlyObject(payload[from:to]), nil
+		}
+		return nil, err
+	}
+
+	return s.payloadOnlyObject(res.PayloadRange()), nil
+}
+
+func (s *multiaddressRemoteStorage) Head(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
+	var prm internalclient.HeadObjectPrm
+
+	prm.SetClient(s.client)
+	prm.SetTTL(requestParams.TTL)
+	prm.SetNetmapEpoch(requestParams.Epoch)
+	prm.SetAddress(address)
+	prm.SetPrivateKey(requestParams.PrivateKey)
+	prm.SetSessionToken(requestParams.SessionToken)
+	prm.SetBearerToken(requestParams.BearerToken)
+	prm.SetXHeaders(requestParams.XHeaders)
+
+	if requestParams.IsRaw {
+		prm.SetRawFlag()
+	}
+
+	res, err := internalclient.HeadObject(ctx, prm)
+	if err != nil {
+		return nil, err
+	}
+
+	return res.Header(), nil
+}
+
+func (s *multiaddressRemoteStorage) Get(ctx context.Context, address oid.Address, requestParams RemoteRequestParams) (*objectSDK.Object, error) {
+	var prm internalclient.GetObjectPrm
+
+	prm.SetClient(s.client)
+	prm.SetTTL(requestParams.TTL)
+	prm.SetNetmapEpoch(requestParams.Epoch)
+	prm.SetAddress(address)
+	prm.SetPrivateKey(requestParams.PrivateKey)
+	prm.SetSessionToken(requestParams.SessionToken)
+	prm.SetBearerToken(requestParams.BearerToken)
+	prm.SetXHeaders(requestParams.XHeaders)
+
+	if requestParams.IsRaw {
+		prm.SetRawFlag()
+	}
+
+	res, err := internalclient.GetObject(ctx, prm)
+	if err != nil {
+		return nil, err
+	}
+
+	return res.Object(), nil
+}
+
+func (s *multiaddressRemoteStorage) payloadOnlyObject(payload []byte) *objectSDK.Object {
+	obj := objectSDK.New()
+	obj.SetPayload(payload)
+
+	return obj
+}
+
+type RangeHashRes struct {
+	hashes [][]byte
+}
+
+func (r *RangeHashRes) Hashes() [][]byte {
+	return r.hashes
+}

pkg/services/object/get/util.go

@@ -1,261 +0,0 @@
-package getsvc
-
-import (
-	"context"
-	"crypto/ecdsa"
-	"errors"
-	"io"
-
-	coreclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/client"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/netmap"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/engine"
-	internalclient "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/internal/client"
-	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
-	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
-)
-
-type SimpleObjectWriter struct {
-	obj *object.Object
-
-	pld []byte
-}
-
-type clientCacheWrapper struct {
-	cache ClientConstructor
-}
-
-type clientWrapper struct {
-	client coreclient.MultiAddressClient
-}
-
-type storageEngineWrapper struct {
-	engine *engine.StorageEngine
-}
-
-type partWriter struct {
-	ObjectWriter
-
-	headWriter HeaderWriter
-
-	chunkWriter ChunkWriter
-}
-
-type hasherWrapper struct {
-	hash io.Writer
-}
-
-type nmSrcWrapper struct {
-	nmSrc netmap.Source
-}
-
-func NewSimpleObjectWriter() *SimpleObjectWriter {
-	return &SimpleObjectWriter{
-		obj: object.New(),
-	}
-}
-
-func (s *SimpleObjectWriter) WriteHeader(_ context.Context, obj *object.Object) error {
-	s.obj = obj
-
-	s.pld = make([]byte, 0, obj.PayloadSize())
-
-	return nil
-}
-
-func (s *SimpleObjectWriter) WriteChunk(_ context.Context, p []byte) error {
-	s.pld = append(s.pld, p...)
-	return nil
-}
-
-func (s *SimpleObjectWriter) Object() *object.Object {
-	if len(s.pld) > 0 {
-		s.obj.SetPayload(s.pld)
-	}
-
-	return s.obj
-}
-
-func (c *clientCacheWrapper) get(info coreclient.NodeInfo) (getClient, error) {
-	clt, err := c.cache.Get(info)
-	if err != nil {
-		return nil, err
-	}
-
-	return &clientWrapper{
-		client: clt,
-	}, nil
-}
-
-func (c *clientWrapper) getObject(ctx context.Context, exec *execCtx, info coreclient.NodeInfo) (*object.Object, error) {
-	if exec.isForwardingEnabled() {
-		return exec.prm.forwarder(ctx, info, c.client)
-	}
-
-	key, err := exec.key()
-	if err != nil {
-		return nil, err
-	}
-
-	if exec.headOnly() {
-		return c.getHeadOnly(ctx, exec, key)
-	}
-	// we don't specify payload writer because we accumulate
-	// the object locally (even huge).
-	if rng := exec.ctxRange(); rng != nil {
-		// Current spec allows other storage node to deny access,
-		// fallback to GET here.
-		return c.getRange(ctx, exec, key, rng)
-	}
-
-	return c.get(ctx, exec, key)
-}
-
-func (c *clientWrapper) getRange(ctx context.Context, exec *execCtx, key *ecdsa.PrivateKey, rng *object.Range) (*object.Object, error) {
-	var prm internalclient.PayloadRangePrm
-
-	prm.SetClient(c.client)
-	prm.SetTTL(exec.prm.common.TTL())
-	prm.SetNetmapEpoch(exec.curProcEpoch)
-	prm.SetAddress(exec.address())
-	prm.SetPrivateKey(key)
-	prm.SetSessionToken(exec.prm.common.SessionToken())
-	prm.SetBearerToken(exec.prm.common.BearerToken())
-	prm.SetXHeaders(exec.prm.common.XHeaders())
-	prm.SetRange(rng)
-
-	if exec.isRaw() {
-		prm.SetRawFlag()
-	}
-
-	res, err := internalclient.PayloadRange(ctx, prm)
-	if err != nil {
-		var errAccessDenied *apistatus.ObjectAccessDenied
-		if errors.As(err, &errAccessDenied) {
-			obj, err := c.get(ctx, exec, key)
-			if err != nil {
-				return nil, err
-			}
-
-			payload := obj.Payload()
-			from := rng.GetOffset()
-			to := from + rng.GetLength()
-
-			if pLen := uint64(len(payload)); to < from || pLen < from || pLen < to {
-				return nil, new(apistatus.ObjectOutOfRange)
-			}
-
-			return payloadOnlyObject(payload[from:to]), nil
-		}
-		return nil, err
-	}
-
-	return payloadOnlyObject(res.PayloadRange()), nil
-}
-
-func (c *clientWrapper) getHeadOnly(ctx context.Context, exec *execCtx, key *ecdsa.PrivateKey) (*object.Object, error) {
-	var prm internalclient.HeadObjectPrm
-
-	prm.SetClient(c.client)
-	prm.SetTTL(exec.prm.common.TTL())
-	prm.SetNetmapEpoch(exec.curProcEpoch)
-	prm.SetAddress(exec.address())
-	prm.SetPrivateKey(key)
-	prm.SetSessionToken(exec.prm.common.SessionToken())
-	prm.SetBearerToken(exec.prm.common.BearerToken())
-	prm.SetXHeaders(exec.prm.common.XHeaders())
-
-	if exec.isRaw() {
-		prm.SetRawFlag()
-	}
-
-	res, err := internalclient.HeadObject(ctx, prm)
-	if err != nil {
-		return nil, err
-	}
-
-	return res.Header(), nil
-}
-
-func (c *clientWrapper) get(ctx context.Context, exec *execCtx, key *ecdsa.PrivateKey) (*object.Object, error) {
-	var prm internalclient.GetObjectPrm
-
-	prm.SetClient(c.client)
-	prm.SetTTL(exec.prm.common.TTL())
-	prm.SetNetmapEpoch(exec.curProcEpoch)
-	prm.SetAddress(exec.address())
-	prm.SetPrivateKey(key)
-	prm.SetSessionToken(exec.prm.common.SessionToken())
-	prm.SetBearerToken(exec.prm.common.BearerToken())
-	prm.SetXHeaders(exec.prm.common.XHeaders())
-
-	if exec.isRaw() {
-		prm.SetRawFlag()
-	}
-
-	res, err := internalclient.GetObject(ctx, prm)
-	if err != nil {
-		return nil, err
-	}
-
-	return res.Object(), nil
-}
-
-func (e *storageEngineWrapper) get(ctx context.Context, exec *execCtx) (*object.Object, error) {
-	if exec.headOnly() {
-		var headPrm engine.HeadPrm
-		headPrm.WithAddress(exec.address())
-		headPrm.WithRaw(exec.isRaw())
-
-		r, err := e.engine.Head(ctx, headPrm)
-		if err != nil {
-			return nil, err
-		}
-
-		return r.Header(), nil
-	} else if rng := exec.ctxRange(); rng != nil {
-		var getRange engine.RngPrm
-		getRange.WithAddress(exec.address())
-		getRange.WithPayloadRange(rng)
-
-		r, err := e.engine.GetRange(ctx, getRange)
-		if err != nil {
-			return nil, err
-		}
-
-		return r.Object(), nil
-	} else {
-		var getPrm engine.GetPrm
-		getPrm.WithAddress(exec.address())
-
-		r, err := e.engine.Get(ctx, getPrm)
-		if err != nil {
-			return nil, err
-		}
-
-		return r.Object(), nil
-	}
-}
-
-func (w *partWriter) WriteChunk(ctx context.Context, p []byte) error {
-	return w.chunkWriter.WriteChunk(ctx, p)
-}
-
-func (w *partWriter) WriteHeader(ctx context.Context, o *object.Object) error {
-	return w.headWriter.WriteHeader(ctx, o)
-}
-
-func payloadOnlyObject(payload []byte) *object.Object {
-	obj := object.New()
-	obj.SetPayload(payload)
-
-	return obj
-}
-
-func (h *hasherWrapper) WriteChunk(_ context.Context, p []byte) error {
-	_, err := h.hash.Write(p)
-	return err
-}
-
-func (n *nmSrcWrapper) currentEpoch() (uint64, error) {
-	return n.nmSrc.Epoch()
-}

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

@@ -0,0 +1,92 @@
+package getsvc
+
+import (
+	"errors"
+	"fmt"
+
+	objectV2 "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
+	refs "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs"
+)
+
+var (
+	errMissingObjAddress   = errors.New("missing object address")
+	errWrongMessageSeq     = errors.New("incorrect message sequence")
+	errNilObjectPart       = errors.New("nil object part")
+	errMissingSignature    = errors.New("missing signature")
+	errInvalidObjectIDSign = errors.New("invalid object ID signature")
+
+	errWrongHeaderPartTypeExpShortRecvWithSignature = fmt.Errorf("wrong header part type: expected %T, received %T",
+		(*objectV2.ShortHeader)(nil), (*objectV2.HeaderWithSignature)(nil),
+	)
+	errWrongHeaderPartTypeExpWithSignRecvShort = fmt.Errorf("wrong header part type: expected %T, received %T",
+		(*objectV2.HeaderWithSignature)(nil), (*objectV2.ShortHeader)(nil),
+	)
+)
+
+func errInvalidObjAddress(err error) error {
+	return fmt.Errorf("invalid object address: %w", err)
+}
+
+func errRequestParamsValidation(err error) error {
+	return fmt.Errorf("request params validation: %w", err)
+}
+
+func errFetchingSessionKey(err error) error {
+	return fmt.Errorf("fetching session key: %w", err)
+}
+
+func errUnknownChechsumType(t refs.ChecksumType) error {
+	return fmt.Errorf("unknown checksum type %v", t)
+}
+
+func errResponseVerificationFailed(err error) error {
+	return fmt.Errorf("response verification failed: %w", err)
+}
+
+func errCouldNotWriteObjHeader(err error) error {
+	return fmt.Errorf("could not write object header in Get forwarder: %w", err)
+}
+
+func errStreamOpenningFailed(err error) error {
+	return fmt.Errorf("stream opening failed: %w", err)
+}
+
+func errReadingResponseFailed(err error) error {
+	return fmt.Errorf("reading the response failed: %w", err)
+}
+
+func errUnexpectedObjectPart(v objectV2.GetObjectPart) error {
+	return fmt.Errorf("unexpected object part %T", v)
+}
+
+func errCouldNotWriteObjChunk(forwarder string, err error) error {
+	return fmt.Errorf("could not write object chunk in %s forwarder: %w", forwarder, err)
+}
+
+func errCouldNotVerifyRangeResponse(resp *objectV2.GetRangeResponse, err error) error {
+	return fmt.Errorf("could not verify %T: %w", resp, err)
+}
+
+func errCouldNotCreateGetRangeStream(err error) error {
+	return fmt.Errorf("could not create Get payload range stream: %w", err)
+}
+
+func errUnexpectedRangePart(v objectV2.GetRangePart) error {
+	return fmt.Errorf("unexpected range type %T", v)
+}
+
+func errUnexpectedHeaderPart(v objectV2.GetHeaderPart) error {
+	return fmt.Errorf("unexpected header type %T", v)
+}
+
+func errMarshalID(err error) error {
+	return fmt.Errorf("marshal ID: %w", err)
+}
+
+func errCantReadSignature(err error) error {
+	return fmt.Errorf("can't read signature: %w", err)
+}
+
+func errSendingRequestFailed(err error) error {
+	return fmt.Errorf("sending the request failed: %w", err)
+}

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

@@ -4,7 +4,6 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"errors"
-	"fmt"
 	"io"
 	"sync"
 
@@ -71,7 +70,7 @@ func (f *getRequestForwarder) verifyResponse(resp *objectV2.GetResponse, pubkey
 
 	// verify response structure
 	if err := signature.VerifyServiceMessage(resp); err != nil {
-		return fmt.Errorf("response verification failed: %w", err)
+		return errResponseVerificationFailed(err)
 	}
 
 	return checkStatus(resp.GetMetaHeader().GetStatus())
@@ -89,7 +88,7 @@ func (f *getRequestForwarder) writeHeader(ctx context.Context, v *objectV2.GetOb
 		err = f.Stream.WriteHeader(ctx, object.NewFromV2(obj))
 	})
 	if err != nil {
-		return fmt.Errorf("could not write object header in Get forwarder: %w", err)
+		return errCouldNotWriteObjHeader(err)
 	}
 	return nil
 }
@@ -102,7 +101,7 @@ func (f *getRequestForwarder) openStream(ctx context.Context, addr network.Addre
 		return e
 	})
 	if err != nil {
-		return nil, fmt.Errorf("stream opening failed: %w", err)
+		return nil, errStreamOpenningFailed(err)
 	}
 	return getStream, nil
 }
@@ -127,7 +126,7 @@ func (f *getRequestForwarder) readStream(ctx context.Context, c client.MultiAddr
 			}
 
 			internalclient.ReportError(c, err)
-			return fmt.Errorf("reading the response failed: %w", err)
+			return errReadingResponseFailed(err)
 		}
 
 		if err := f.verifyResponse(resp, pubkey); err != nil {
@@ -136,7 +135,7 @@ func (f *getRequestForwarder) readStream(ctx context.Context, c client.MultiAddr
 
 		switch v := resp.GetBody().GetObjectPart().(type) {
 		default:
-			return fmt.Errorf("unexpected object part %T", v)
+			return errUnexpectedObjectPart(v)
 		case *objectV2.GetObjectPartInit:
 			if headWas {
 				return errWrongMessageSeq
@@ -159,7 +158,7 @@ func (f *getRequestForwarder) readStream(ctx context.Context, c client.MultiAddr
 			}
 
 			if err = f.Stream.WriteChunk(ctx, chunk); err != nil {
-				return fmt.Errorf("could not write object chunk in Get forwarder: %w", err)
+				return errCouldNotWriteObjChunk("Get", err)
 			}
 
 			localProgress += len(origChunk)

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

@@ -4,7 +4,6 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"errors"
-	"fmt"
 	"io"
 	"sync"
 
@@ -73,7 +72,7 @@ func (f *getRangeRequestForwarder) verifyResponse(resp *objectV2.GetRangeRespons
 
 	// verify response structure
 	if err := signature.VerifyServiceMessage(resp); err != nil {
-		return fmt.Errorf("could not verify %T: %w", resp, err)
+		return errCouldNotVerifyRangeResponse(resp, err)
 	}
 
 	return checkStatus(resp.GetMetaHeader().GetStatus())
@@ -88,7 +87,7 @@ func (f *getRangeRequestForwarder) openStream(ctx context.Context, addr network.
 		return e
 	})
 	if err != nil {
-		return nil, fmt.Errorf("could not create Get payload range stream: %w", err)
+		return nil, errCouldNotCreateGetRangeStream(err)
 	}
 	return rangeStream, nil
 }
@@ -105,7 +104,7 @@ func (f *getRangeRequestForwarder) readStream(ctx context.Context, rangeStream *
 				break
 			}
 			internalclient.ReportError(c, err)
-			return fmt.Errorf("reading the response failed: %w", err)
+			return errReadingResponseFailed(err)
 		}
 
 		if err := f.verifyResponse(resp, pubkey); err != nil {
@@ -114,7 +113,7 @@ func (f *getRangeRequestForwarder) readStream(ctx context.Context, rangeStream *
 
 		switch v := resp.GetBody().GetRangePart().(type) {
 		case nil:
-			return fmt.Errorf("unexpected range type %T", v)
+			return errUnexpectedRangePart(v)
 		case *objectV2.GetRangePartChunk:
 			origChunk := v.GetChunk()
 
@@ -125,7 +124,7 @@ func (f *getRangeRequestForwarder) readStream(ctx context.Context, rangeStream *
 			}
 
 			if err = f.Stream.WriteChunk(ctx, chunk); err != nil {
-				return fmt.Errorf("could not write object chunk in GetRange forwarder: %w", err)
+				return errCouldNotWriteObjChunk("GetRange", err)
 			}
 
 			localProgress += len(origChunk)

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

@@ -3,8 +3,6 @@ package getsvc
 import (
 	"context"
 	"crypto/ecdsa"
-	"errors"
-	"fmt"
 	"sync"
 
 	objectV2 "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
@@ -74,7 +72,7 @@ func (f *headRequestForwarder) forwardRequestToNode(ctx context.Context, addr ne
 
 	switch v := headResp.GetBody().GetHeaderPart().(type) {
 	case nil:
-		return nil, fmt.Errorf("unexpected header type %T", v)
+		return nil, errUnexpectedHeaderPart(v)
 	case *objectV2.ShortHeader:
 		if hdr, err = f.getHeaderFromShortHeader(v); err != nil {
 			return nil, err
@@ -100,9 +98,7 @@ func (f *headRequestForwarder) forwardRequestToNode(ctx context.Context, addr ne
 
 func (f *headRequestForwarder) getHeaderFromShortHeader(sh *objectV2.ShortHeader) (*objectV2.Header, error) {
 	if !f.Request.GetBody().GetMainOnly() {
-		return nil, fmt.Errorf("wrong header part type: expected %T, received %T",
+		return nil, errWrongHeaderPartTypeExpShortRecvWithSignature
-			(*objectV2.ShortHeader)(nil), (*objectV2.HeaderWithSignature)(nil),
-		)
 	}
 
 	hdr := new(objectV2.Header)
@@ -118,35 +114,32 @@ func (f *headRequestForwarder) getHeaderFromShortHeader(sh *objectV2.ShortHeader
 
 func (f *headRequestForwarder) getHeaderAndSignature(hdrWithSig *objectV2.HeaderWithSignature) (*objectV2.Header, *refs.Signature, error) {
 	if f.Request.GetBody().GetMainOnly() {
-		return nil, nil, fmt.Errorf("wrong header part type: expected %T, received %T",
+		return nil, nil, errWrongHeaderPartTypeExpWithSignRecvShort
-			(*objectV2.HeaderWithSignature)(nil), (*objectV2.ShortHeader)(nil),
-		)
 	}
 
 	if hdrWithSig == nil {
-		return nil, nil, errors.New("nil object part")
+		return nil, nil, errNilObjectPart
 	}
 
 	hdr := hdrWithSig.GetHeader()
 	idSig := hdrWithSig.GetSignature()
 
 	if idSig == nil {
-		// TODO(@cthulhu-rider): #1387 use "const" error
+		return nil, nil, errMissingSignature
-		return nil, nil, errors.New("missing signature")
 	}
 
 	binID, err := f.ObjectAddr.Object().Marshal()
 	if err != nil {
-		return nil, nil, fmt.Errorf("marshal ID: %w", err)
+		return nil, nil, errMarshalID(err)
 	}
 
 	var sig frostfscrypto.Signature
 	if err := sig.ReadFromV2(*idSig); err != nil {
-		return nil, nil, fmt.Errorf("can't read signature: %w", err)
+		return nil, nil, errCantReadSignature(err)
 	}
 
 	if !sig.Verify(binID) {
-		return nil, nil, errors.New("invalid object ID signature")
+		return nil, nil, errInvalidObjectIDSign
 	}
 
 	return hdr, idSig, nil
@@ -160,7 +153,7 @@ func (f *headRequestForwarder) sendHeadRequest(ctx context.Context, addr network
 		return e
 	})
 	if err != nil {
-		return nil, fmt.Errorf("sending the request failed: %w", err)
+		return nil, errSendingRequestFailed(err)
 	}
 	return headResp, nil
 }
@@ -173,7 +166,7 @@ func (f *headRequestForwarder) verifyResponse(headResp *objectV2.HeadResponse, p
 
 	// verify response structure
 	if err := signature.VerifyServiceMessage(headResp); err != nil {
-		return fmt.Errorf("response verification failed: %w", err)
+		return errResponseVerificationFailed(err)
 	}
 
 	return checkStatus(f.Response.GetMetaHeader().GetStatus())

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

@@ -4,7 +4,6 @@ import (
 	"context"
 	"crypto/sha256"
 	"errors"
-	"fmt"
 	"hash"
 	"sync"
 
@@ -24,21 +23,19 @@ import (
 	"git.frostfs.info/TrueCloudLab/tzhash/tz"
 )
 
-var errWrongMessageSeq = errors.New("incorrect message sequence")
-
 func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStream) (*getsvc.Prm, error) {
 	body := req.GetBody()
 
 	addrV2 := body.GetAddress()
 	if addrV2 == nil {
-		return nil, errors.New("missing object address")
+		return nil, errMissingObjAddress
 	}
 
 	var addr oid.Address
 
 	err := addr.ReadFromV2(*addrV2)
 	if err != nil {
-		return nil, fmt.Errorf("invalid object address: %w", err)
+		return nil, errInvalidObjAddress(err)
 	}
 
 	commonPrm, err := util.CommonPrmFromV2(req)
@@ -81,14 +78,14 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 
 	addrV2 := body.GetAddress()
 	if addrV2 == nil {
-		return nil, errors.New("missing object address")
+		return nil, errMissingObjAddress
 	}
 
 	var addr oid.Address
 
 	err := addr.ReadFromV2(*addrV2)
 	if err != nil {
-		return nil, fmt.Errorf("invalid object address: %w", err)
+		return nil, errInvalidObjAddress(err)
 	}
 
 	commonPrm, err := util.CommonPrmFromV2(req)
@@ -108,7 +105,7 @@ func (s *Service) toRangePrm(req *objectV2.GetRangeRequest, stream objectSvc.Get
 
 	err = p.Validate()
 	if err != nil {
-		return nil, fmt.Errorf("request params validation: %w", err)
+		return nil, errRequestParamsValidation(err)
 	}
 
 	if !commonPrm.LocalOnly() {
@@ -136,14 +133,14 @@ func (s *Service) toHashRangePrm(req *objectV2.GetRangeHashRequest) (*getsvc.Ran
 
 	addrV2 := body.GetAddress()
 	if addrV2 == nil {
-		return nil, errors.New("missing object address")
+		return nil, errMissingObjAddress
 	}
 
 	var addr oid.Address
 
 	err := addr.ReadFromV2(*addrV2)
 	if err != nil {
-		return nil, fmt.Errorf("invalid object address: %w", err)
+		return nil, errInvalidObjAddress(err)
 	}
 
 	commonPrm, err := util.CommonPrmFromV2(req)
@@ -167,7 +164,7 @@ func (s *Service) toHashRangePrm(req *objectV2.GetRangeHashRequest) (*getsvc.Ran
 		}
 
 		if err != nil {
-			return nil, fmt.Errorf("fetching session key: %w", err)
+			return nil, errFetchingSessionKey(err)
 		}
 
 		p.WithCachedSignerKey(signerKey)
@@ -185,7 +182,7 @@ func (s *Service) toHashRangePrm(req *objectV2.GetRangeHashRequest) (*getsvc.Ran
 
 	switch t := body.GetType(); t {
 	default:
-		return nil, fmt.Errorf("unknown checksum type %v", t)
+		return nil, errUnknownChechsumType(t)
 	case refs.SHA256:
 		p.SetHashGenerator(func() hash.Hash {
 			return sha256.New()
@@ -220,14 +217,14 @@ func (s *Service) toHeadPrm(req *objectV2.HeadRequest, resp *objectV2.HeadRespon
 
 	addrV2 := body.GetAddress()
 	if addrV2 == nil {
-		return nil, errors.New("missing object address")
+		return nil, errMissingObjAddress
 	}
 
 	var objAddr oid.Address
 
 	err := objAddr.ReadFromV2(*addrV2)
 	if err != nil {
-		return nil, fmt.Errorf("invalid object address: %w", err)
+		return nil, errInvalidObjAddress(err)
 	}
 
 	commonPrm, err := util.CommonPrmFromV2(req)

pkg/services/object/get/writer.go

@@ -0,0 +1,84 @@
+package getsvc
+
+import (
+	"context"
+	"io"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+)
+
+// ChunkWriter is an interface of target component
+// to write payload chunk.
+type ChunkWriter interface {
+	WriteChunk(context.Context, []byte) error
+}
+
+// HeaderWriter is an interface of target component
+// to write object header.
+type HeaderWriter interface {
+	WriteHeader(context.Context, *object.Object) error
+}
+
+// ObjectWriter is an interface of target component to write object.
+type ObjectWriter interface {
+	HeaderWriter
+	ChunkWriter
+}
+
+type SimpleObjectWriter struct {
+	obj *object.Object
+
+	pld []byte
+}
+
+type partWriter struct {
+	ObjectWriter
+
+	headWriter HeaderWriter
+
+	chunkWriter ChunkWriter
+}
+
+type hasherWrapper struct {
+	hash io.Writer
+}
+
+func NewSimpleObjectWriter() *SimpleObjectWriter {
+	return &SimpleObjectWriter{
+		obj: object.New(),
+	}
+}
+
+func (s *SimpleObjectWriter) WriteHeader(_ context.Context, obj *object.Object) error {
+	s.obj = obj
+
+	s.pld = make([]byte, 0, obj.PayloadSize())
+
+	return nil
+}
+
+func (s *SimpleObjectWriter) WriteChunk(_ context.Context, p []byte) error {
+	s.pld = append(s.pld, p...)
+	return nil
+}
+
+func (s *SimpleObjectWriter) Object() *object.Object {
+	if len(s.pld) > 0 {
+		s.obj.SetPayload(s.pld)
+	}
+
+	return s.obj
+}
+
+func (w *partWriter) WriteChunk(ctx context.Context, p []byte) error {
+	return w.chunkWriter.WriteChunk(ctx, p)
+}
+
+func (w *partWriter) WriteHeader(ctx context.Context, o *object.Object) error {
+	return w.headWriter.WriteHeader(ctx, o)
+}
+
+func (h *hasherWrapper) WriteChunk(_ context.Context, p []byte) error {
+	_, err := h.hash.Write(p)
+	return err
+}