为什么芹菜记录到终端？

Question

我试图让Celery记录到文件中。 我的log_config.yaml是：

version: 1

formatters:
  default:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'

loggers:

  sqlalchemy:
    level: CRITICAL
    handlers: [debug_handler]

  pepko.app:
    level: INFO
    handlers: [debug_handler]

  celery:
    handlers: [debug_handler]
    level: DEBUG


handlers:
  debug_handler:
    class: logging.handlers.RotatingFileHandler
    formatter: default
    filename: pepkologs.log
    backupCount: 2
    level: DEBUG

root:
  level: DEBUG
  handlers: [debug_handler]

我有

flask_app.config['CELERYD_HIJACK_ROOT_LOGGER'] = True

但芹菜还在写

[2017-09-22 11:45:08,800: DEBUG/MainProcess] | Worker: Starting Beat
[2017-09-22 11:45:08,802: DEBUG/MainProcess] ^-- substep ok
[2017-09-22 11:45:08,805: DEBUG/MainProcess] | Worker: Starting Hub
[2017-09-22 11:45:08,808: DEBUG/MainProcess] ^-- substep ok

和终端的另一个东西。我做错了什么？