KarrLab/obj_tables

# an example transformations program
from obj_tables.migrate import MigrationWrapper, MigratorError


class TransformationExample(MigrationWrapper):

    def prepare_existing_models(self, migrator, existing_models):
        """ Prepare existing models before migration

        Convert ``Test.size`` values to integers before they are migrated

        Args:
            migrator (:obj:`Migrator`:) the :obj:`Migrator` calling this method
            existing_models (:obj:`list` of :obj:`obj_tables.Model`:) the models
                that will be migrated
        """
        try:
            for existing_model in existing_models:
                if isinstance(existing_model, migrator.existing_defs['Test']):
                    existing_model.size = int(existing_model.size)
        except KeyError:
            raise MigratorError("KeyError: cannot find model 'Test' in existing definitions")

    def modify_migrated_models(self, migrator, migrated_models):
        """ Modify migrated models after migration

        Args:
            migrator (:obj:`Migrator`:) the :obj:`Migrator` calling this method
            migrated_models (:obj:`list` of :obj:`obj_tables.Model`:) all models
                that have been migrated
        """
        pass


# a MigrationWrapper subclass instance must be assigned to :obj:`transformations`
transformations = TransformationExample()