Another way to solve this is to have a local import in local_settings for settings. Example local_settings.py:

def get_setting(setting):
    import settings
    return getattr(settings, setting)

INSTALLED_APPS = get_setting('INSTALLED_APPS') + ('debug_toolbar', )
MIDDLEWARE_CLASSES = get_setting('MIDDLEWARE_CLASSES') + ('debug_toolbar.middleware.DebugToolbarMiddleware',)
INTERNAL_IPS = ('127.0.0.1',)

Thanks Antti, I've never seen that page before. There's some pretty interesting solutions on there.

I decided to go with Harro's solution of using a default_settings.py file, along with a local_settings.py to override those values. It works nicely, and the right things stay out of version control.

See also http://code.djangoproject.com/wiki/SplitSettings for a collection of solutions.

Rather than having a local_settings.py that could override an unknown group of settings, I use a more deterministic setup. In settings.py, I pull specific settings from local_settings, requiring all local_settings.py variations to declare all potentially modifiable values.

For example, in settings.py:

import local_settings
DEBUG = local_settings.DEBUG

I find this to be a little more robust that the commonly used local_settings trick. It helps me to avoid mistakes like forgetting local_settings when deploying to a new server. Rather than having the app accidentally run with DEBUG set to True (bad practice in itself to have it set to true in settings.py, but I digress), the app will simply fail to run because local_settings does not exist.

Plus, that way, I have no need for local_settings.py to reference anything from settings.py. It should only need things contained within itself or from Django's default settings.

This is slightly off-topic but I try to version everything except credentials which I keep in a separate directory well clear of the development area. I can put all creds in one place in files with a .cred extension and just fetch them when required like this ...

credsdir = '/srv/www/' + APP + '/creds/'
creds =  credsdir + 'database.cred'
def getcreds(fname=creds):
"""
This is only for keeping credentials out of the repository when
settings.py is under version control provided always that CREDS itself
isn't versioned!!! creds still needs to be invisible in the filesystem
to every user except the http server - chmod 0700. chown wwwrun:www
The first line of creds is userid, next is password and 
subsequent lines can contain comments or anything really.
"""
fh = open(fname, 'r')
cred = [fh.readline().strip(), fh.readline().strip()]
fh.close()
return cred

Then cred[0] is the userid and cred[1] is the password

Do as Daniel says an move the settings to default settings.
Then in the default settings do:

try:
    from local_settings import *
except ImportError
    from default_settings import *

And in your local_settings do a:

from default_settings import *

Then you can put stuff in the local settings and everything will still work even if there are no local settings

Why not simply rename the original settings.py to something like default_settings.py, then create a new, empty settings.py with the following in it:

from default_settings.py import *
MIDDLEWARE_CLASSES += ('debug_toolbar.middleware.DebugToolbarMiddleware',)
INTERNAL_IPS = ('127.0.0.1',)
INSTALLED_APPS += ('debug_toolbar',)
MY_CUSTOM_PARAM = 'foo'

Hi,
I use a different techinique.
At the end of my setting file I put this:

from conf import *

"Conf" is a folder/module inside the same folder with this inside:

conf/
    __init__.py
    development.py
    staging.py
    production.py

The init.py looks like this:

"""
The HOSTMAP variable is a dictionary of lists, the keys representing
roles of a server, the values representing the hostnames of machines that
fill those roles.
You can get your hostname by typing `hostname` into a terminal.
"""

-
import socket, warnings, sys
from django.utils.importlib import import_module
HOSTMAP = {
'development': [
'iRule',
'rfc-1918',
'ubuntu',
],
'staging': [
'vps2728.webhosting.uk.com',
],
'production': [
# 'vps2728.webhosting.uk.com',
],
}

def update_current_settings(file_name):
    """
    Given a filename, this function will insert all variables and
    functions in ALL_CAPS into the global scope.
    """
    new_settings = import_module(file_name)

    for k, v in new_settings.__dict__.items():
        if k.upper() == k:
            globals().update({k:v})

current_hostname = socket.gethostname()
to_load = []

for k, v in HOSTMAP.items():
    if current_hostname in v:
        to_load.append(k)

for x in to_load:
    new_settings_path= 'brokenseal.conf.%s' % x
    try:
        update_current_settings(new_settings_path)
    except ImportError:
        warnings.warn("Failed to import %s" % new_settings_path)

This way, no matter where I am, the right settings will be imported.

Have a look here: http://github.com/brokenseal/brokenseal
and here: https://gist.github.com/217198/1e3b5e44b23abcfe0cb57c6470c832cd0b23e83f

Cheers,
David