Source code for app_utils.app_settings

"""Django settings related utilities."""

import logging
from typing import Any, Optional

from django.conf import settings

logger = logging.getLogger(__name__)




def clean_setting(
    name: str,
    default_value: Any,
    min_value: Optional[int] = None,
    max_value: Optional[int] = None,
    required_type: Optional[type] = None,
    choices: Optional[list] = None,
) -> Any:
    """Clean a setting from Django settings.

    Will use default_value if setting is not defined.
    Will use minimum or maximum value if respective boundary is exceeded.

    Args:
        default_value: value to use if setting is not defined
        min_value: minimum allowed value (0 assumed for int)
        max_value: maximum value value
        required_type: Mandatory if `default_value` is `None`,
        otherwise derived from default_value

    Returns:
        cleaned value for setting

    This function is designed to be used in a dedicated module like ``app_settings.py``
    as layer between the actual settings and all other modules.
    ``app_settings.py`` will import and clean all settings and all other modules are supposed to import the settings it.

    Example for app_settings:

    .. code-block:: python

        from app_utils.app_settings import clean_setting

        EXAMPLE_SETTING = clean_setting("EXAMPLE_SETTING", 10)
    """
    if default_value is None and not required_type:
        raise ValueError("You must specify a required_type for None defaults")

    if not required_type:
        required_type_2 = type(default_value)
    else:
        required_type_2 = required_type

    if not isinstance(required_type_2, type):
        raise TypeError("required_type must be a type when defined")

    if min_value is None and issubclass(required_type_2, int):
        min_value = 0

    if issubclass(required_type_2, int) and default_value is not None:
        if min_value is not None and default_value < min_value:
            raise ValueError("default_value can not be below min_value")
        if max_value is not None and default_value > max_value:
            raise ValueError("default_value can not be above max_value")

    if not hasattr(settings, name):
        cleaned_value = default_value
    else:
        dirty_value = getattr(settings, name)
        if dirty_value is None or (
            isinstance(dirty_value, required_type_2)
            and (min_value is None or dirty_value >= min_value)
            and (max_value is None or dirty_value <= max_value)
            and (choices is None or dirty_value in choices)
        ):
            cleaned_value = dirty_value
        elif (
            isinstance(dirty_value, required_type_2)
            and min_value is not None
            and dirty_value < min_value
        ):
            logger.warning(
                "You setting for %s it not valid. Please correct it. "
                "Using minimum value for now: %s",
                name,
                min_value,
            )
            cleaned_value = min_value
        elif (
            isinstance(dirty_value, required_type_2)
            and max_value is not None
            and dirty_value > max_value
        ):
            logger.warning(
                "You setting for %s it not valid. Please correct it. "
                "Using maximum value for now: %s",
                name,
                max_value,
            )
            cleaned_value = max_value
        else:
            logger.warning(
                "You setting for %s it not valid. Please correct it. "
                "Using default for now: %s",
                name,
                default_value,
            )
            cleaned_value = default_value
    return cleaned_value