[#84] Add netmap service executor and signer

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/services/netmap/executor.go

@@ -0,0 +1,41 @@
+package netmap
+
+import (
+	"context"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg"
+	"github.com/nspcc-dev/neofs-api-go/v2/netmap"
+	"github.com/nspcc-dev/neofs-api-go/v2/session"
+)
+
+type executorSvc struct {
+	version       *pkg.Version
+	localNodeInfo *netmap.NodeInfo
+}
+
+func NewExecutionService(ni *netmap.NodeInfo, v *pkg.Version) netmap.Service {
+	if ni == nil || v == nil {
+		// this should never happen, otherwise it programmers bug
+		panic("can't create netmap execution service")
+	}
+
+	return &executorSvc{
+		version:       v,
+		localNodeInfo: ni,
+	}
+}
+
+func (s *executorSvc) LocalNodeInfo(
+	_ context.Context,
+	_ *netmap.LocalNodeInfoRequest) (*netmap.LocalNodeInfoResponse, error) {
+
+	body := new(netmap.LocalNodeInfoResponseBody)
+	body.SetVersion(s.version.ToV2())
+	body.SetNodeInfo(s.localNodeInfo)
+
+	resp := new(netmap.LocalNodeInfoResponse)
+	resp.SetBody(body)
+	resp.SetMetaHeader(new(session.ResponseMetaHeader))
+
+	return resp, nil
+}

pkg/services/netmap/sign.go

@@ -0,0 +1,38 @@
+package netmap
+
+import (
+	"context"
+	"crypto/ecdsa"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/netmap"
+	"github.com/nspcc-dev/neofs-node/pkg/services/util"
+)
+
+type signService struct {
+	sigSvc *util.SignService
+
+	svc netmap.Service
+}
+
+func NewSignService(key *ecdsa.PrivateKey, svc netmap.Service) netmap.Service {
+	return &signService{
+		sigSvc: util.NewUnarySignService(key),
+		svc:    svc,
+	}
+}
+
+func (s *signService) LocalNodeInfo(
+	ctx context.Context,
+	req *netmap.LocalNodeInfoRequest) (*netmap.LocalNodeInfoResponse, error) {
+
+	resp, err := s.sigSvc.HandleUnaryRequest(ctx, req,
+		func(ctx context.Context, req interface{}) (interface{}, error) {
+			return s.svc.LocalNodeInfo(ctx, req.(*netmap.LocalNodeInfoRequest))
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp.(*netmap.LocalNodeInfoResponse), nil
+}