dao.py 文件源码

def get_latest_snapshot_timestamp(self, statuses):
        """Select the latest timestamp of the completed snapshot.

        Args:
            statuses (tuple): The tuple of snapshot statuses to filter on.

        Returns:
            str: The string timestamp of the latest complete snapshot.

        Raises:
            MySQLError: When no rows are found.
        """
        # Build a dynamic parameterized query string for filtering the
        # snapshot statuses
        if not isinstance(statuses, tuple):
            statuses = ('SUCCESS',)

        status_params = ','.join(['%s']*len(statuses))
        filter_clause = SNAPSHOT_STATUS_FILTER_CLAUSE.format(status_params)
        try:
            cursor = self.conn.cursor()
            cursor.execute(
                select_data.LATEST_SNAPSHOT_TIMESTAMP + filter_clause, statuses)
            row = cursor.fetchone()
            if row:
                return row[0]
            raise NoResultsError('No snapshot cycle found.')
        except (DataError, IntegrityError, InternalError, NotSupportedError,
                OperationalError, ProgrammingError, NoResultsError) as e:
            raise MySQLError('snapshot_cycles', e)