django-configurations eases Django project configuration by relying on the composability of Python classes. It extends the notion of Django’s module based settings loading with well established object oriented programming patterns.
pip install django-configurations
Then subclass the included configurations.Settings class in your project’s settings.py or any other module you’re using to store the settings constants, e.g.:
# mysite/settings.py from configurations import Settings class Dev(Settings): DEBUG = True
Set the DJANGO_CONFIGURATION environment variable to the name of the class you just created, e.g. in bash:
and the DJANGO_SETTINGS_MODULE environment variable to the module import path as usual, e.g. in bash:
Alternatively supply the --configuration option when using Django management commands along the lines of Django’s default --settings command line option, e.g.:
python manage.py runserver --settings=mysite.settings --configuration=Dev
To enable Django to use your configuration you now have to modify your manage.py or wsgi.py script to use django-configurations’s versions of the appropriate starter functions, e.g. a typical manage.py using django-configurations would look like this:
#!/usr/bin/env python import os import sys if __name__ == "__main__": os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'mysite.settings') os.environ.setdefault('DJANGO_CONFIGURATION', 'Dev') from configurations.management import execute_from_command_line execute_from_command_line(sys.argv)
Notice in line 9 we don’t use the common tool django.core.management.execute_from_command_line but instead configurations.management.execute_from_command_line.
The same applies to your wsgi.py file, e.g.:
import os os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'mysite.settings') os.environ.setdefault('DJANGO_CONFIGURATION', 'Dev') from configurations.wsgi import get_wsgi_application application = get_wsgi_application()
Here we don’t use the default django.core.wsgi.get_wsgi_application function but instead configurations.wsgi.get_wsgi_application.
That’s it! You can now use your project with manage.py and your favorite WSGI enabled server.
django-configurations helps you organize the configuration of your Django project by providing the glue code to bridge between Django’s module based settings system and programming patterns like mixins, facades, factories and adapters that are useful for non-trivial configuration scenarios.
It allows you to use the native abilities of Python inheritance without the side effects of module level namespaces that often lead to the unfortunate use of the from foo import * anti-pattern.
Any subclass of the configurations.Settings class will automatically use the values of its class and instance attributes (including properties and methods) to set module level variables of the same module – that’s how Django will interface to the django-configurations based settings during startup and also the reason why it requires you to use its own startup functions.
That means when Django starts up django-configurations will have a look at the DJANGO_CONFIGURATION environment variable to figure out which class in the settings module (as defined by the DJANGO_SETTINGS_MODULE environment variable) should be used for the process. It then instantiates the class defined with DJANGO_CONFIGURATION and copies the uppercase attributes to the module level variables.
New in version 0.2.
Alternatively you can use the --configuration command line option that django-configurations adds to all Django management commands. Behind the scenes it will simply set the DJANGO_CONFIGURATION environement variable so this is purely optional and just there to compliment the default --settings option that Django adds if you prefer that instead of setting environment variables.
Yes, it looks like magic, but it’s also maintainable and non-intrusive. No monkey patching is needed to teach Django how to load settings via django-configurations because it uses Python import hooks (PEP 302) behind the scenes.
There are various configuration patterns that can be implemented with django-configurations. The most common pattern is to have a base class and various subclasses based on the enviroment they are supposed to be used in, e.g. in production, staging and development.
For example, imagine you have a base setting class in your settings.py file:
from configurations import Settings class Base(Settings): TIME_ZONE = 'Europe/Berlin' class Dev(Base): DEBUG = True TEMPLATE_DEBUG = DEBUG class Prod(Base): TIME_ZONE = 'America/New_York'
You can now set the DJANGO_CONFIGURATION environment variable to one of the class names you’ve defined, e.g. on your production server it should be Prod. In bash that would be:
export DJANGO_SETTINGS_MODULE=mysite.settings export DJANGO_CONFIGURATION=Prod python manage.py runserver
Alternatively you can use the --configuration option when using Django management commands along the lines of Django’s default --settings command line option, e.g.:
python manage.py runserver --settings=mysite.settings --configuration=Prod
Every configurations.Settings subclass will automatically contain Django’s global settings as class attributes, so you can refer to them when setting other values, e.g.:
from configurations import Settings class Prod(Settings): TEMPLATE_CONTEXT_PROCESSORS = Settings.TEMPLATE_CONTEXT_PROCESSORS + ( 'django.core.context_processors.request', ) @property def LANGUAGES(self): return Settings.LANGUAGES + (('tlh', 'Klingon'),)
You might want to apply some configuration values for each and every project you’re working on without having to repeat yourself. Just define a few mixin you re-use multiple times:
class FullPageCaching(object): USE_ETAGS = True
Then import that mixin class in your site settings module and use it with a Settings class:
from configurations import Settings class Prod(Settings, FullPageCaching): DEBUG = False # ...
New in version 0.3.
In case one of your settings itself need to be a callable, you need to tell that django-configurations by using the pristinemethod decorator, e.g.:
from configurations import Settings, pristinemethod class Prod(Settings): @pristinemethod def ACCESS_FUNCTION(user): return user.is_staff
Lambdas work, too:
from configurations import Settings, pristinemethod class Prod(Settings): ACCESS_FUNCTION = pristinemethod(lambda user: user.is_staff)
New in version 0.3.
If there is something required to be set up before or after the settings loading happens, please override the pre_setup or post_setup class methods like so (don’t forget to apply the Python @classmethod decorator:
from configurations import Settings class Prod(Settings): # ... @classmethod def pre_setup(cls): if something.completely.different(): cls.DEBUG = True @classmethod def post_setup(cls): print("done setting up! \o/")
As you can see above the pre_setup method can also be used to programmatically change a class attribute of the settings class and it will be taken into account when doing the rest of the settings setup. Of course that won’t work for post_setup since that’s when the settings setup is already done.
In fact you can easily do something unrelated to settings, like connecting to a database:
from configurations import Settings class Prod(Settings): # ... @classmethod def post_setup(cls): import mango mango.connect('enterprise')
You could do the same by overriding the __init__ method of your settings class but this may cause hard to debug errors because at the time the __init__ method is called (during Django startup) the Django setting system isn’t fully loaded yet.
So anything you do in __init__ that may require django.conf.settings or Django models there is a good chance it won’t work. Use the post_setup method for that instead.
Many thanks to those project that have previously solved these problems:
Given Celery’s way to load Django settings in worker processes you should probably just add the following to the begin of your settings module:
from configurations import importer importer.install()
That has the same effect as using the manage.py or wsgi.py utilities mentioned above.
In case you use FastCGI for deploying Django (you really shouldn’t) and aren’t allowed to us Django’s runfcgi management command (that would automatically handle the setup for your if you’ve followed the quickstart guide above), make sure to use something like the following script:
#!/usr/bin/env python import os import sys os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'mysite.settings') os.environ.setdefault('DJANGO_CONFIGURATION', 'MySiteSettings') from configurations.fastcgi import runfastcgi runfastcgi(method='threaded', daemonize='true')
As you can see django-configurations provides a helper module configurations.fastcgi that handles the setup of your configurations.
As always you mileage may vary, so please don’t hesitate to send in feature requests and bug reports at the usual place: