[#109] object/put: Implement remote object sender

Define RemoteSender structure with PutObject method that puts object to a
remote node locally.

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

pkg/services/object/put/remote.go

@@ -28,6 +28,19 @@ type remoteTarget struct {
 	obj *object.Object
 }
 
+// RemoteSender represents utility for
+// sending an object to a remote host.
+type RemoteSender struct {
+	keyStorage *util.KeyStorage
+}
+
+// RemotePutPrm groups remote put operation parameters.
+type RemotePutPrm struct {
+	node *network.Address
+
+	obj *object.Object
+}
+
 func (t *remoteTarget) WriteHeader(obj *object.RawObject) error {
 	t.obj = obj.Object()
 
@@ -66,3 +79,45 @@ func (t *remoteTarget) Close() (*transformer.AccessIdentifiers, error) {
 	return new(transformer.AccessIdentifiers).
 		WithSelfID(id), nil
 }
+
+// NewRemoteSender creates, initializes and returns new RemoteSender instance.
+func NewRemoteSender(keyStorage *util.KeyStorage) *RemoteSender {
+	return &RemoteSender{
+		keyStorage: keyStorage,
+	}
+}
+
+// WithNodeAddress sets network address of the remote node.
+func (p *RemotePutPrm) WithNodeAddress(v *network.Address) *RemotePutPrm {
+	if p != nil {
+		p.node = v
+	}
+
+	return p
+}
+
+// WithObject sets transferred object.
+func (p *RemotePutPrm) WithObject(v *object.Object) *RemotePutPrm {
+	if p != nil {
+		p.obj = v
+	}
+
+	return p
+}
+
+// PutObject sends object to remote node.
+func (s *RemoteSender) PutObject(ctx context.Context, p *RemotePutPrm) error {
+	t := &remoteTarget{
+		ctx:        ctx,
+		keyStorage: s.keyStorage,
+		addr:       p.node,
+	}
+
+	if err := t.WriteHeader(object.NewRawFromObject(p.obj)); err != nil {
+		return errors.Wrapf(err, "(%T) could not send object header", s)
+	} else if _, err := t.Close(); err != nil {
+		return errors.Wrapf(err, "(%T) could not send object", s)
+	}
+
+	return nil
+}