Dynamic Django settings

Features

Easily migrate your static settings to dynamic settings.
Admin interface to edit the dynamic settings.

Installation

Install from PyPI:

pip install django-constance

Or install the in-development version using pip:

pip install -e git+git://github.com/comoga/django-constance#egg=django-constance

Configuration

Modify your settings.py. Add 'constance' to your INSTALLED_APPS, and move each key you want to turn dynamic into the CONSTANCE_CONFIG section, like this:

INSTALLED_APPS = (
    ...
    'constance',
)

CONSTANCE_CONFIG = {
    'MY_SETTINGS_KEY': (42, 'the answer to everything'),
}

Here, 42 is the default value for the key MY_SETTINGS_KEY if it is not found in the backend. The other member of the tuple is a help text the admin will show.

See the Backends section how to setup the backend.

Backends

Constance ships with a bunch of backends that are used to store the configuration values. By default it uses the Redis backend. To override the default please set the CONSTANCE_BACKEND setting to the appropriate dotted path.

Redis (default)

CONSTANCE_BACKEND = 'constance.backends.redisd.RedisBackend'

The is the default backend and has a couple of options:

CONSTANCE_REDIS_CONNECTION

A dictionary of parameters to pass to the to Redis client, e.g.:

CONSTANCE_REDIS_CONNECTION = {
    'host': 'localhost',
    'port': 6379,
    'db': 0,
}

CONSTANCE_REDIS_CONNECTION_CLASS

An (optional) dotted import path to a connection to use, e.g.:
```
CONSTANCE_REDIS_CONNECTION_CLASS = 'myproject.myapp.mockup.Connection'
```
CONSTANCE_REDIS_PREFIX

The (optional) prefix to be used for the key when storing in the Redis database. Defaults to 'constance:'. E.g.:
```
CONSTANCE_REDIS_PREFIX = 'constance:myproject:'
```

Database

CONSTANCE_BACKEND = constance.backends.database.DatabaseBackend

If you want to use this backend you also need to add the databse backend to your INSTALLED_APPS setting to make sure the data model is correctly created:

INSTALLED_APPS = (
    # other apps
    'constance.backends.database',
)

It also uses django-picklefield to store the values in the database, so you need to install this library, too. E.g.:

pip install django-picklefield

The database backend has the ability to automatically cache the config values and clear them when saving. You need to set the following setting to enable this feature:

CONSTANCE_DATABASE_CACHE_BACKEND = 'memcached://127.0.0.1:11211/'

Note

This won't work with a cache backend that doesn't support cross-process caching, because correct cache invalidation can't be guaranteed.

Usage

Constance can be used from your Python code and from your Django templates.

Python

Accessing the config variables is as easy as importing the config object and accessing the variables with attribute lookups:
```
from constance import config

# ...

if config.MY_SETTINGS_KEY == 42:
    answer_the_question()
```

Django templates

To access the config object from your template, you can either pass the object to the template context:

from django.shortcuts import render_to_response
from constance import config

def myview(request):
    return render_to_response('my_template.html', {'config': config})

Or you can use the included config context processor.:

TEMPLATE_CONTEXT_PROCESSORS = (
    # ...
    'constance.context_processors.config',
)

This will add the config instance to the context of any template rendered with a RequestContext.

Then, in your template you can refer to the config values just as any other variable, e.g.:

<h1>Welcome on {% config.SITE_NAME %}</h1>
{% if config.BETA_LAUNCHED %}
    Woohoo! Head over <a href="/sekrit/">here</a> to use the beta.
{% else %}
    Sadly we haven't launched yet, click <a href="/newsletter/">here</a>
    to signup for our newletter.
{% endif %}

Editing

Fire up your admin and you should see a new app called Constance with MY_SETTINGS_KEY in the Config pseudo model.

Screenshots

https://github.com/comoga/django-constance/raw/master/docs/screenshot2.png

The standard edit screen.

https://github.com/comoga/django-constance/raw/master/docs/screenshot1.png

The virtual application Constance among your regular applications.

egrachev/django-constance