utils.py 文件源码

def create_shadow_table(migrate_engine, table_name=None, table=None,
                        **col_name_col_instance):
    """This method create shadow table for table with name ``table_name``
    or table instance ``table``.
    :param table_name: Autoload table with this name and create shadow table
    :param table: Autoloaded table, so just create corresponding shadow table.
    :param col_name_col_instance:   contains pair column_name=column_instance.
    column_instance is instance of Column. These params are required only for
    columns that have unsupported types by sqlite. For example BigInteger.
    :returns: The created shadow_table object.
    """
    meta = MetaData(bind=migrate_engine)

    if table_name is None and table is None:
        raise exception.NovaException(_("Specify `table_name` or `table` "
                                        "param"))
    if not (table_name is None or table is None):
        raise exception.NovaException(_("Specify only one param `table_name` "
                                        "`table`"))

    if table is None:
        table = Table(table_name, meta, autoload=True)

    columns = []
    for column in table.columns:
        if isinstance(column.type, NullType):
            new_column = oslodbutils._get_not_supported_column(
                col_name_col_instance, column.name)
            columns.append(new_column)
        else:
            columns.append(column.copy())

    shadow_table_name = db._SHADOW_TABLE_PREFIX + table.name
    shadow_table = Table(shadow_table_name, meta, *columns,
                         mysql_engine='InnoDB')
    try:
        shadow_table.create()
        return shadow_table
    except (db_exc.DBError, OperationalError):
        # NOTE(ekudryashova): At the moment there is a case in oslo.db code,
        # which raises unwrapped OperationalError, so we should catch it until
        # oslo.db would wraps all such exceptions
        LOG.info(repr(shadow_table))
        LOG.exception(_LE('Exception while creating table.'))
        raise exception.ShadowTableExists(name=shadow_table_name)
    except Exception:
        LOG.info(repr(shadow_table))
        LOG.exception(_LE('Exception while creating table.'))