django-app-settings.py

"""Collect settings for this app from django settings."""

from django.core.exceptions import ImproperlyConfigured


class NotSetButRequired(object):

    def __repr__(self):
        return '<{0}>'.format(self.__class__.__name__)


NOT_SET_BUT_REQUIRED = NotSetButRequired()
SETTINGS = {
    "FOO": NOT_SET_BUT_REQUIRED,
    "BAR": "qux.baz",
}


def get_setting(setting_name):
    from django.conf import settings

    SETTINGS_USER = getattr(settings, "FOOBAR_SETTINGS", {})
    SETTING_NAME = setting_name.upper()

    SETTINGS.update(SETTINGS_USER)

    try:
        value = SETTINGS[SETTING_NAME]

        if value is NOT_SET_BUT_REQUIRED:
            error_msg = "FOOBAR_SETTINGS['{}'] is a required setting but is unset".format(SETTING_NAME)
            raise ImproperlyConfigured(error_msg)
        else:
            return value

    except KeyError:
        raise KeyError("Got unsupported settings key {}".format(SETTING_NAME))

    except Exception:
        print("Caught unhandled exception while accessing FOOBAR_SETTINGS")
        raise

settings.py

# ... Other django settings above

FOOBAR_SETTINGS = {
    "FOO": "http://example.com",
    "BAR": "animals.kittens",
}

# How to override ...

FOOBAR_SETTINGS.update({
  "FOO": "http://google.com",
})

Just a quick gist based on some generic django app settings:

• Explicitly declare / handle settings access
• Settings, if they are required, and their default values are self-documenting
• Provide simple api to get settings from django.conf.settings: get_setting
• Simplify setting access by allowing lowercase setting keys
• Raise a useful error if a setting is required but not configured
• Raise a useful error if a setting is not supported
• Provide setting namespace FOOBAR_SETTINGS