diff --git a/container/container.go b/container/container.go
index 11cd097..c07e3ec 100644
--- a/container/container.go
+++ b/container/container.go
@@ -50,8 +50,6 @@ const (
 
 // reads Container from the container.Container message. If checkFieldPresence is set,
 // returns an error on absence of any protocol-required field.
-//
-// nolint: funlen
 func (x *Container) readFromV2(m container.Container, checkFieldPresence bool) error {
 	var err error
 
@@ -98,6 +96,16 @@ func (x *Container) readFromV2(m container.Container, checkFieldPresence bool) e
 		return errors.New("missing placement policy")
 	}
 
+	if err := checkAttributes(m); err != nil {
+		return err
+	}
+
+	x.v2 = m
+
+	return nil
+}
+
+func checkAttributes(m container.Container) error {
 	attrs := m.GetAttributes()
 	mAttr := make(map[string]struct{}, len(attrs))
 	var key, val string
@@ -119,6 +127,7 @@ func (x *Container) readFromV2(m container.Container, checkFieldPresence bool) e
 			return fmt.Errorf("empty attribute value %s", key)
 		}
 
+		var err error
 		switch key {
 		case container.SysAttributeSubnet:
 			err = new(subnetid.ID).DecodeString(val)
@@ -132,9 +141,6 @@ func (x *Container) readFromV2(m container.Container, checkFieldPresence bool) e
 
 		mAttr[key] = struct{}{}
 	}
-
-	x.v2 = m
-
 	return nil
 }