Comment 4 for bug 1528349

FYI, the code in Nova may look the same right now, but that's only because it was not following nova best practice. That method needs converting to use Nova's nova.objects.ImageMeta model instead of using anonymous dicts, since Nova's intends to 100% eliminate passing & use of dicts for image properties in favour of an explicit model. So if there is a desire to share the code, it wouldl have to be re-factored so that all the neccessary signature relatsed parameters are explicitly passed in, rather than passing in the image meta dict directly.