[#52] services/object: Implement Get service

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/object/get/prm.go

@@ -0,0 +1,27 @@
+package getsvc
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+)
+
+type Prm struct {
+	local, full bool
+
+	addr *object.Address
+}
+
+func (p *Prm) OnlyLocal(v bool) *Prm {
+	if p != nil {
+		p.local = v
+	}
+
+	return p
+}
+
+func (p *Prm) WithAddress(v *object.Address) *Prm {
+	if p != nil {
+		p.addr = v
+	}
+
+	return p
+}

pkg/services/object/get/service.go

@@ -0,0 +1,55 @@
+package getsvc
+
+import (
+	"context"
+
+	rangesvc "github.com/nspcc-dev/neofs-node/pkg/services/object/range"
+	"github.com/pkg/errors"
+)
+
+type Service struct {
+	*cfg
+}
+
+type Option func(*cfg)
+
+type cfg struct {
+	rngSvc *rangesvc.Service
+}
+
+func defaultCfg() *cfg {
+	return new(cfg)
+}
+
+func NewService(opts ...Option) *Service {
+	c := defaultCfg()
+
+	for i := range opts {
+		opts[i](c)
+	}
+
+	return &Service{
+		cfg: c,
+	}
+}
+
+func (s *Service) Get(ctx context.Context, prm *Prm) (*Streamer, error) {
+	r, err := s.rngSvc.GetRange(ctx, new(rangesvc.Prm).
+		WithAddress(prm.addr).
+		FullRange().
+		OnlyLocal(prm.local),
+	)
+	if err != nil {
+		return nil, errors.Wrapf(err, "(%T) could not get range", s)
+	}
+
+	return &Streamer{
+		rngRes: r,
+	}, nil
+}
+
+func WithRangeService(v *rangesvc.Service) Option {
+	return func(c *cfg) {
+		c.rngSvc = v
+	}
+}

pkg/services/object/get/streamer.go

@@ -0,0 +1,26 @@
+package getsvc
+
+import (
+	rangesvc "github.com/nspcc-dev/neofs-node/pkg/services/object/range"
+	"github.com/pkg/errors"
+)
+
+type Streamer struct {
+	headSent bool
+
+	rngRes *rangesvc.Result
+}
+
+func (p *Streamer) Recv() (interface{}, error) {
+	if !p.headSent {
+		p.headSent = true
+		return p.rngRes.Head(), nil
+	}
+
+	rngResp, err := p.rngRes.Stream().Recv()
+	if err != nil {
+		return nil, errors.Wrapf(err, "(%T) could not receive range response", p)
+	}
+
+	return rngResp.PayloadChunk(), nil
+}

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

@@ -0,0 +1,50 @@
+package getsvc
+
+import (
+	"context"
+
+	objectV2 "github.com/nspcc-dev/neofs-api-go/v2/object"
+	getsvc "github.com/nspcc-dev/neofs-node/pkg/services/object/get"
+	"github.com/pkg/errors"
+)
+
+// Service implements Get operation of Object service v2.
+type Service struct {
+	*cfg
+}
+
+// Option represents Service constructor option.
+type Option func(*cfg)
+
+type cfg struct {
+	svc *getsvc.Service
+}
+
+// NewService constructs Service instance from provided options.
+func NewService(opts ...Option) *Service {
+	c := new(cfg)
+
+	for i := range opts {
+		opts[i](c)
+	}
+
+	return &Service{
+		cfg: c,
+	}
+}
+
+// Get calls internal service and returns v2 object stream.
+func (s *Service) Get(ctx context.Context, req *objectV2.GetRequest) (objectV2.GetObjectStreamer, error) {
+	stream, err := s.svc.Get(ctx, toPrm(req))
+	if err != nil {
+		return nil, errors.Wrapf(err, "(%T) could not get object payload range data", s)
+	}
+
+	return fromResponse(stream), nil
+}
+
+func WithInternalService(v *getsvc.Service) Option {
+	return func(c *cfg) {
+		c.svc = v
+	}
+}

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

@@ -0,0 +1,47 @@
+package getsvc
+
+import (
+	"fmt"
+
+	objectV2 "github.com/nspcc-dev/neofs-api-go/v2/object"
+	"github.com/nspcc-dev/neofs-node/pkg/core/object"
+	getsvc "github.com/nspcc-dev/neofs-node/pkg/services/object/get"
+	"github.com/pkg/errors"
+)
+
+type streamer struct {
+	stream *getsvc.Streamer
+
+	body *objectV2.GetResponseBody
+}
+
+func (s *streamer) Recv() (*objectV2.GetResponse, error) {
+	r, err := s.stream.Recv()
+	if err != nil {
+		return nil, errors.Wrapf(err, "(%T) could not receive get response", s)
+	}
+
+	switch v := r.(type) {
+	case *object.Object:
+		oV2 := v.ToV2()
+
+		partInit := new(objectV2.GetObjectPartInit)
+		partInit.SetHeader(oV2.GetHeader())
+		partInit.SetSignature(oV2.GetSignature())
+		partInit.SetObjectID(oV2.GetObjectID())
+
+		s.body.SetObjectPart(partInit)
+	case []byte:
+		partChunk := new(objectV2.GetObjectPartChunk)
+		partChunk.SetChunk(v)
+
+		s.body.SetObjectPart(partChunk)
+	default:
+		panic(fmt.Sprintf("unexpected response type %T from %T", r, s.stream))
+	}
+
+	resp := new(objectV2.GetResponse)
+	resp.SetBody(s.body)
+
+	return resp, nil
+}

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

@@ -0,0 +1,22 @@
+package getsvc
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	objectV2 "github.com/nspcc-dev/neofs-api-go/v2/object"
+	getsvc "github.com/nspcc-dev/neofs-node/pkg/services/object/get"
+)
+
+func toPrm(req *objectV2.GetRequest) *getsvc.Prm {
+	return new(getsvc.Prm).
+		WithAddress(
+			object.NewAddressFromV2(req.GetBody().GetAddress()),
+		).
+		OnlyLocal(req.GetMetaHeader().GetTTL() == 1) // FIXME: use constant
+}
+
+func fromResponse(res *getsvc.Streamer) objectV2.GetObjectStreamer {
+	return &streamer{
+		stream: res,
+		body:   new(objectV2.GetResponseBody),
+	}
+}