Separate custom settings variable between development, staging and production - django

Question

I'm following the project structure as laid out by Zachary Voase, but I'm struggling with one specific issue.
I'd very much like to have a custom settings boolean variable (let's call it SEND_LIVE_MAIL) that I would be using in the project. Basically, I'd like to use this settings variable in my code and if SEND_LIVE_MAIL is True actually send out a mail, whereas when it is set to False just print its contents out to the console. The latter would apply to the dev environment and when running unittests.
What would be a good way of implementing this? Currently, depending on the environment, the django server uses dev, staging or prd settings, but for custom settings variables I believe these need to be imported 'literally'. In other words, I'd be using in my views something like
from settings.development import SEND_LIVE_MAIL
which of course isn't what I want. I'd like to be able to do something like:
from settings import SEND_LIVE_MAIL
and depending on the environment, the correct value is assigned to the SEND_LIVE_MAIL variable.
Thanks in advance!

Answer 1

You shouldn't be importing directly from your settings files anyways. Use:
>>> from django.conf import settings
>>> settings.SEND_LIVE_MAIL
True

Answer 2

The simplest solution is to have this at the bottom of your settings file:
try:
from local_settings import *
except ImportError:
pass
And in local_settings.py specify all your environment-specific overrides. I generally don't commit this file to version control.
There are more advanced ways of doing it, where you end up with a default settings file and a per-environment override.
This article by David Cramer covers the various approaches, including both of the ones I've mentioned: http://justcramer.com/2011/01/13/settings-in-django/

Answer 3

import os
PROJECT_PATH = os.path.dirname(__file__)
try:
execfile(os.path.join(PROJECT_PATH, local_settings.py'))
except IOError:
pass
Then you can have your local_settings.py behave as if it was pasted directly into your settings.py:
$ cat local_settings.py
INSTALLED_APPS += ['foo']

Answer 4

You can do something like this for a wide variety of environment based settings, but here's an example for just SEND_LIVE_MAIL.
settings_config.py
import re
import socket
class Config:
def __init__(self):
fqdn = socket.getfqdn()
env = re.search(r'(devhost|stagehost|prodhost)', fqdn)
env = env and env.group(1)
env = env or 'devhost'
if env == 'devhost':
self.SEND_LIVE_MAIL = # whatever
elif env == 'stagehost':
self.SEND_LIVE_MAIL = # whatever
elif env == 'prodhost':
self.SEND_LIVE_MAIL = # whatever
config = Config()
settings.py
from settings_config import config
SEND_LIVE_MAIL = config.SEND_LIVE_MAIL