Allow to select billing period when registering VM

uncloud/uncloud_vm/views.py

@@ -32,19 +32,23 @@ class VMProductViewSet(ProductViewSet):
     # if something goes wrong.
     @transaction.atomic
     def create(self, request):
+        # Extract serializer data.
+        serializer = VMProductSerializer(data=request.data, context={'request': request})
+        serializer.is_valid(raise_exception=True)
+        order_recurring_period = serializer.validated_data.pop("recurring_period")
+
         # Create base order.
         order = Order.objects.create(
-                recurring_period=RecurringPeriod.PER_MONTH,
+                recurring_period=order_recurring_period,
                 owner=request.user
                 )
         order.save()
 
         # Create VM.
-        serializer = VMProductSerializer(data=request.data, context={'request': request})
-        serializer.is_valid(raise_exception=True)
         vm = serializer.save(owner=request.user, order=order)
 
         # Add Product record to order (VM is mutable, allows to keep history in order).
+        # XXX: Move this to some kind of on_create hook in parent Product class?
         order.add_record(vm.setup_fee,
                 vm.recurring_price(order.recurring_period), vm.description)