def is_cacheable(self, image_id):
        # Make sure we're not already cached or caching the image
        return not (self.is_cached(image_id) or
                    self.is_being_cached(image_id))
Returns True if the image with the supplied ID can have its
dataset/ETHPy150Open rcbops/glance-buildpackage/glance/image_cache/drivers/sqlite.py/Driver.is_cacheable