db.py 文件源码

def cursor(self):
        """
        Returns a database cursor, automatically re-opening the database
        connection if necessary.

        """
        try:
            try:
                cursor = self.db.cursor()
                cursor.execute('SELECT 1')
            except psycopg2.InternalError as err:
                if err.pgcode == IN_FAILED_SQL_TRANSACTION:
                    LOGGER.critical("Rolling back aborted transaction...")
                    self.db.rollback()
                else:
                    LOGGER.critical("PostgreSQL reported an internal error "
                                    "I don't know how to handle: %s "
                                    "(code=%s)", pg_err_lookup(err.pgcode),
                                    err.pgcode)
                    raise
        except Exception as err:
            if self.db is not None:
                LOGGER.critical("Could not get cursor. Trying to reconnect...",
                                exc_info=True)
            self.close()
            self.connect()
            cursor = self.db.cursor()
        return cursor