[#142] sdk/container: Add converters to and from v2

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

pkg/client/container.go

@@ -100,7 +100,7 @@ func (c Client) putContainerV2(ctx context.Context, cnr *container.Container, op
 	}
 
 	reqBody := new(v2container.PutRequestBody)
-	reqBody.SetContainer(&cnr.Container)
+	reqBody.SetContainer(cnr.ToV2())
 
 	// sign container
 	signWrapper := v2signature.StableMarshalerWrapper{SM: reqBody.GetContainer()}
@@ -182,9 +182,7 @@ func (c Client) getContainerV2(ctx context.Context, id *container.ID, opts ...Ca
 			return nil, errors.Wrap(err, "can't verify response message")
 		}
 
-		return &container.Container{
-			Container: *resp.GetBody().GetContainer(),
-		}, nil
+		return container.NewContainerFromV2(resp.GetBody().GetContainer()), nil
 	default:
 		return nil, unsupportedProtocolErr
 	}

pkg/container/container.go

@@ -8,7 +8,7 @@ type Container struct {
 	container.Container
 }
 
-func New(opts ...NewOption) (*Container, error) {
+func New(opts ...NewOption) *Container {
 	cnrOptions := defaultContainerOptions()
 	for i := range opts {
 		opts[i].apply(&cnrOptions)
@@ -18,14 +18,14 @@ func New(opts ...NewOption) (*Container, error) {
 	cnr.SetNonce(cnrOptions.nonce[:])
 	cnr.SetBasicACL(cnrOptions.acl)
 
-	if cnrOptions.policy != "" {
-		// todo: set placement policy
-	}
-
 	if cnrOptions.owner != nil {
 		cnr.SetOwnerID(cnrOptions.owner.ToV2())
 	}
 
+	if cnrOptions.policy != nil {
+		cnr.SetPlacementPolicy(cnrOptions.policy)
+	}
+
 	attributes := make([]*container.Attribute, len(cnrOptions.attributes))
 	for i := range cnrOptions.attributes {
 		attribute := new(container.Attribute)
@@ -37,5 +37,19 @@ func New(opts ...NewOption) (*Container, error) {
 		cnr.SetAttributes(attributes)
 	}
 
-	return cnr, nil
+	return cnr
+}
+
+func (c Container) ToV2() *container.Container {
+	return &c.Container
+}
+
+func NewContainerFromV2(c *container.Container) *Container {
+	cnr := new(Container)
+
+	if c != nil {
+		cnr.Container = *c
+	}
+
+	return cnr
 }