Cannot use environment variables for settings in Django

Question

In trying to find a place to store and save settings beyond settings.py and the database, I used an environment.json for environment variables. I import these in settings.py.

My problem is that when I try to change or store new values in my environment, env, settings.py does not notice the change - perhaps because the time and number of times settings.py is read by Django.

Is there a way I would be able to use my environment variables the way I want like attempted below?

# settings.py
import json
with open('/home/dotcloud/environment.json') as f:
    env = json.load(f)
EMAIL_HOST = env.get('EMAIL_PORT', '500')

# views.py
import json
def site_configuration(request):
    with open('/home/dotcloud/environment.json') as f:
        env = json.load(f)
    if request.method == 'POST':
        os.environ['EMAIL_PORT'] = request.POST['email_port']
    return render(request, ...)

# python manage.py shell demo
>>> import json
>>> with open('/home/dotcloud/environment.json') as f:
...     env = json.load(f)
... 
>>> project_settings.EMAIL_PORT
'500'
>>> env['EMAIL_PORT']
Traceback (most recent call last):
  File "<console>", line 1, in <module>
KeyError: 'EMAIL_PORT'
>>> env['EMAIL_PORT'] = "123"
>>> env['EMAIL_PORT']
'123'
>>> project_settings.EMAIL_PORT
'500'
>>> project_settings.EMAIL_PORT == env['EMAIL_PORT']
False'

And if not, how else could I store changeable settings that are retrieved by settings.py somewhere in my Django project?

Answer 1

You might want to look into foreman (GitHub) or honcho (GitHub). Both of these look for a .env file in your current directory from which to load local environment variables.

My .env looks like this for most projects (I use dj-database-url for database configuration):

DATABASE_URL=sqlite://localhost/local.db
SECRET_KEY=<a secret key>
DEBUG=True

In your settings.py file, you can load these settings from os.environ like this:

import os
DEBUG = os.environ.get('DEBUG', False)

If there are required settings, you can assert their presence before trying to set them:

assert 'SECRET_KEY' in os.environ, 'Set SECRET_KEY in your .env file!'
SECRET_KEY = os.environ['SECRET_KEY']

I've been using this method of handling local settings for the last few projects I've started and I think it works really well. One caveat is to never commit your .env to source control. These are local settings that exist only for the current configuration and should be recreated for a different environment.