session.py 文件源码

def read_session(function):
    '''
    decorator that set the session variable to use inside a function.
    With that decorator it's possible to use the session variable like if a global variable session is declared.

    session is a sqlalchemy session, and you can get one calling get_session().
    This is useful if only SELECTs and the like are being done; anything involving
    INSERTs, UPDATEs etc should use transactional_session.
    '''
    @retry(retry_on_exception=retry_if_db_connection_error,
           wait_fixed=0.5,
           stop_max_attempt_number=2,
           wrap_exception=False)
    @wraps(function)
    def new_funct(*args, **kwargs):

        if isgeneratorfunction(function):
            raise RucioException('read_session decorator should not be used with generator. Use stream_session instead.')

        if not kwargs.get('session'):
            session = get_session()
            try:
                kwargs['session'] = session
                return function(*args, **kwargs)
            except TimeoutError, error:
                session.rollback()  # pylint: disable=maybe-no-member
                raise DatabaseException(str(error))
            except DatabaseError, error:
                session.rollback()  # pylint: disable=maybe-no-member
                raise DatabaseException(str(error))
            except:
                session.rollback()  # pylint: disable=maybe-no-member
                raise
            finally:
                session.remove()
        try:
            return function(*args, **kwargs)
        except:
            raise
    new_funct.__doc__ = function.__doc__
    return new_funct