Usage patterns¶
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.
Server specific settings¶
For example, imagine you have a base setting class in your settings.py file:
from configurations import Configuration
class Base(Configuration):
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
Global settings defaults¶
Every configurations.Configuration
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 Configuration
class Prod(Configuration):
TEMPLATE_CONTEXT_PROCESSORS = Configuration.TEMPLATE_CONTEXT_PROCESSORS + (
'django.core.context_processors.request',
)
@property
def LANGUAGES(self):
return list(Configuration.LANGUAGES) + [('tlh', 'Klingon')]
Configuration mixins¶
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 Configuration
class:
from configurations import Configuration
class Prod(FullPageCaching, Configuration):
DEBUG = False
# ...
Pristine methods¶
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 Configuration, pristinemethod
class Prod(Configuration):
@pristinemethod
def ACCESS_FUNCTION(user):
return user.is_staff
Lambdas work, too:
from configurations import Configuration, pristinemethod
class Prod(Configuration):
ACCESS_FUNCTION = pristinemethod(lambda user: user.is_staff)
Setup methods¶
New in version 0.3.
If there is something required to be set up before, during or after the
settings loading happens, please override the pre_setup
, setup
or
post_setup
class methods like so (don’t forget to apply the Python
@classmethod
decorator):
import logging
from configurations import Configuration
class Prod(Configuration):
# ...
@classmethod
def pre_setup(cls):
super(Prod, cls).pre_setup()
if something.completely.different():
cls.DEBUG = True
@classmethod
def setup(cls):
super(Prod, cls).setup()
logging.info('production settings loaded: %s', cls)
@classmethod
def post_setup(cls):
super(Prod, cls).post_setup()
logging.debug("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 Configuration
class Prod(Configuration):
# ...
@classmethod
def post_setup(cls):
import mango
mango.connect('enterprise')
Warning
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.
Changed in version 0.4: A new setup
method was added to be able to handle the new
Value
classes and allow an in-between
modification of the configuration values.
Standalone scripts¶
If you want to run scripts outside of your project you need to add these lines on top of your file:
import configurations
configurations.setup()