Unable to output elastalert.log

[negi700]

I set logging, but elastalert.log cannot be output.
I am troubled.
Please tell me the cause and the countermeasure.

The purpose is elastalert log output.
/var/log/elastalert.log

setting

elastalert-config.yamll

#Custom logging configuration
#If you want to setup your own logging configuration to log into
#files as well or to Logstash and/or modify log levels, use
#the configuration below and adjust to your needs.
#Note: if you run ElastAlert with --verbose/--debug, the log level of
#the "elastalert" logger is changed to INFO, if not already INFO/DEBUG.
logging:
  version: 1
  incremental: false
  disable_existing_loggers: false
  formatters:
    logline:
      format: '%(asctime)s %(levelname)+8s %(name)+20s %(message)s'

    handlers:
      console:
        class: logging.StreamHandler
        formatter: logline
        level: DEBUG
        stream: ext://sys.stderr

      file:
        class : logging.FileHandler
        formatter: logline
        level: DEBUG
        filename: /var/log/elastalert.log

    loggers:
      elastalert:
        level: WARN
        handlers: []
        propagate: true

      elasticsearch:
        level: WARN
        handlers: []
        propagate: true

      elasticsearch.trace:
        level: WARN
        handlers: []
        propagate: true

      '':  # root logger
        level: WARN
        handlers:
          - console
          - file
        propagate: false

[negi700]

Solved.
When config.yaml was modified, log output was possible.

Correction points

config.yaml

before
     '':  # root logger
       level: WARN
         handlers:
           - console
           - file
       propagate: false

after
      '':  # root logger
        level: WARN
        handlers:
          - console
          - file
        propagate: false