config.json

{
  "version": 1,

  "disable_existing_loggers": false,

  "formatters": {
        "simple": {
            "format": "%(levelname)s: %(message)s"
        }
    },

  "handlers": {
    "stdout": {
      "class": "logging.StreamHandler",
      "formatter": "simple",
      "stream": "ext://sys.stdout"
    },

    "stderr": {
      "class": "logging.StreamHandler",
      "formatter": "simple",
      "stream": "ext://sys.stderr"
    },

    "file": {
      "class": "logging.handlers.RotatingFileHandler",
      "formatter": "simple",
      "filename": "logs/app.log",
      "maxBytes": 1024,
      "backupCount": 5
    }
  },

  "loggers": {
  "root": {
    "level": "INFO",
    "handlers": [
      "stdout", 
      "stderr",
      "file"
    ],
    "propagate": false
  }
  }
}