common.py 文件源码

def get_conn():
    """
    Get a database connection

    Ensures that only one global database connection exists per thread.
    If the connection does not exist a new one is created and returned.
    """

    if external_client is not None:
        return external_client

    global __client, __connection
    if not __connection:
        try:
            __client = MongoClient(mongo_addr, mongo_port)
            __connection = __client[mongo_db_name]
        except ConnectionFailure:
            raise SevereInternalException("Could not connect to mongo database {} at {}:{}".format(mongo_db_name, mongo_addr, mongo_port))
        except InvalidName as error:
            raise SevereInternalException("Database {} is invalid! - {}".format(mongo_db_name, error))

    return __connection