So part of being a 12-factor app is storing your config in your environment (http://12factor.net/config). This is how I do that using Django settings files. This is the code companion for a blog post (http://blog.ipoots.com/post/43154090079/how-to-achieve-12-factor-app-config-glory-with-django). A similar blog post is http://www.wellfireinteract…

settings.py

# Django settings for dnsly project.
from unipath import FSPath as Path
import os

def env(key, default=None):
    """Retrieves env vars and makes Python boolean replacements"""
    val = os.getenv(key, default)

    if val == 'True':
        val = True
    elif val == 'False':
        val = False
    return val

#Path Settings
PROJECT_DIR = Path(__file__).absolute().ancestor(2)

DEBUG = False
TEMPLATE_DEBUG = DEBUG
 
ADMINS = (
    ('Brian Jinwright', 'brian@example.com'),
)

CURRENT_SITE = env('CURRENT_SITE')
#Static Files Settings
STATIC_ROOT = PROJECT_DIR.child('static')
STATICFILES_DIRS = (
    PROJECT_DIR.ancestor(1).child('static'),    
    )

STATICFILES_FINDERS = ('django.contrib.staticfiles.finders.FileSystemFinder',
    'django.contrib.staticfiles.finders.AppDirectoriesFinder',
    'compressor.finders.CompressorFinder'
    )

STATIC_URL = env('STATIC_URL')
#Site Media Settings
MEDIA_ROOT = PROJECT_DIR.child('site_media')

MEDIA_URL = env('MEDIA_URL')

MANAGERS = ADMINS

LOGIN_URL = env('LOGIN_URL')

TIME_ZONE = env('TIME_ZONE')

LANGUAGE_CODE = env('LANGUAGE_CODE')

SITE_ID = env('SITE_ID')

USE_I18N = env('USE_I18N')

USE_L10N = env('USE_L10N')

AUTH_PROFILE_MODULE = env('AUTH_PROFILE_MODULE')

SECRET_KEY = env('SECRET_KEY')

TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.Loader',
    'django.template.loaders.app_directories.Loader',
)

MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    
)

ROOT_URLCONF = env('ROOT_URLCONF')
LOGIN_REDIRECT_URL = env('LOGIN_REDIRECT_URL')

#Template Directory
TEMPLATE_DIRS = (
    PROJECT_DIR.child('templates'),
)

CACHES = {
    'default': {
        'BACKEND': env('CACHE_BACKEND'),
        'LOCATION': env('CACHE_HOST'),
    }
}

INSTALLED_APPS = (    
    'django.contrib.messages',
    'django.contrib.sessions',
    'django.contrib.staticfiles',
)

ACCOUNT_ACTIVATION_DAYS = env('ACCOUNT_ACTIVATION_DAYS')
TEST_RUNNER = env('TEST_RUNNER')

TEMPLATE_CONTEXT_PROCESSORS = (
    "django.core.context_processors.debug",
    'django.contrib.auth.context_processors.auth',
    'django.core.context_processors.i18n',
    'django.core.context_processors.request',
    "django.core.context_processors.static",
    'django.contrib.messages.context_processors.messages',
    
)

#Email Settings
DEFAULT_FROM_EMAIL = env('DEFAULT_FROM_EMAIL')
EMAIL_BACKEND = env('EMAIL_BACKEND')
SERVER_EMAIL = env('SERVER_EMAIL')


SESSION_ENGINE = env('SESSION_ENGINE')

#SaaS Settings 
AWS_ACCESS_KEY_ID = env('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = env('AWS_SECRET_ACCESS_KEY')


STRIPE_SECRET = env('STRIPE_SECRET')
STRIPE_PUBLISHABLE = env('STRIPE_PUBLISHABLE')

MAILCHIMP_API_KEY = env('MAILCHIMP_API_KEY')
MAILCHIMP_WEBHOOK_KEY = env('MAILCHIMP_WEBHOOK_KEY')

CURRENT_ENV = env('CURRENT_ENV')
#Django Secure Settings
SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')


if CURRENT_ENV != 'development':

    MIDDLEWARE_CLASSES += (
        "djangosecure.middleware.SecurityMiddleware",
                           )
    INSTALLED_APPS += (
        'djangosecure',
                       )
    SECURE_SSL_REDIRECT = env('SECURE_SSL_REDIRECT',False)
    
    SECURE_FRAME_DENY = env('SECURE_FRAME_DENY',False)
    SECURE_BROWSER_XSS_FILTER = env('SECURE_BROWSER_XSS_FILTER',False)
    SESSION_COOKIE_SECURE = env('SESSION_COOKIE_SECURE',False)
    SESSION_COOKIE_HTTPONLY = env('SESSION_COOKIE_HTTPONLY',False)
    SECURE_HSTS_SECONDS = env('SECURE_HSTS_SECONDS',False)
    SECURE_HSTS_INCLUDE_SUBDOMAINS = env('SECURE_HSTS_INCLUDE_SUBDOMAINS',False)
    SECURE_CONTENT_TYPE_NOSNIFF = env('SECURE_CONTENT_TYPE_NOSNIFF',False)