Add logging to Django management commands

management_command.py

import logging

from django.core.management.base import BaseCommand

VERBOSITY_ERROR = 0
VERBOSITY_WARNING = 1
VERBOSITY_NOTICE = 2
VERBOSITY_SUCCESS = 3

LEVEL_ERROR = "error"
LEVEL_WARNING = "warning"
LEVEL_NOTICE = "notice"
LEVEL_SUCCESS = "success"

DEFAULT_VERBOSITY = VERBOSITY_ERROR


class LoggingBaseCommand(BaseCommand):
    """Base class for management commands.
    
    Log all messages to the module logger.
    Send messages to the stdout/stderr according to the verbosity option.
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._logger = logging.getLogger(self.__module__)
        self._verbosity = DEFAULT_VERBOSITY

    def handle(self, *args, **options):
        self._verbosity = options.get("verbosity", DEFAULT_VERBOSITY)

    def _send_to_log(self, message: str, level: str) -> None:
        """Send message to the defult log file."""
        if level == LEVEL_SUCCESS:
            self._logger.info(message)
        elif level == LEVEL_WARNING:
            self._logger.warning(message)
        elif level == LEVEL_NOTICE:
            self._logger.debug(message)
        elif level == LEVEL_ERROR:
            self._logger.error(message)

    def _send_to_console(self, message: str, level: str):
        """Print message to stdout/stderr according to the option `verbosity`."""
        if level == LEVEL_SUCCESS and self._verbosity >= VERBOSITY_SUCCESS:
            self.stdout.write(self.style.SUCCESS(message))

        elif level == LEVEL_WARNING and self._verbosity >= VERBOSITY_WARNING:
            self.stdout.write(self.style.WARNING(message))

        elif level == LEVEL_NOTICE and self._verbosity >= VERBOSITY_NOTICE:
            self.stdout.write(self.style.NOTICE(message))

        elif level == LEVEL_ERROR:
            self.stderr.write(self.style.ERROR(message))

    def log(self, message: str, level: str = LEVEL_SUCCESS) -> None:
        """Print the message with the given level to stdout/stderr."""
        if level not in (LEVEL_ERROR, LEVEL_WARNING, LEVEL_NOTICE, LEVEL_SUCCESS):
            raise ValueError(f"Unknown log level: {level}")

        self._send_to_log(message, level)
        self._send_to_console(message, level)