Installation ============ Usage ===== .. code-block:: python def generate_filename(instance, filename): return f"{instance.parent.storage}:some_folder/{filename}" class SomeParentModel(models.Model): storage = models.ForeignKey('byostorage.UserStorage', on_delete=models.CASCADE) class MyModel(models.Model): parent = models.ForeignKey('SomeParentModel', on_delete=models.CASCADE) photo = models.FileField( storage=BYOStorage(), upload_to=generate_filename)