Manage different Django settings within a Django project, and easily select settings from the command line or from WSGI. Different settings can be helpful either on a single computer, but django-environments is also intended for use on different system environments, such as development, test, staging/acceptance and production, all with "maximum DRY™".
On the command line, you specify your project and settings using environment variables and (mostly) shell functions. When you run your application via WSGI, a simple naming convention determines which settings to use based on the name of the WSGI file. All this helps to minimize the number of code changes and other file updates when working across different environments.
Django-environments moves the settings.py to a settings package, and suggests a settings inheritance model, which you can adhere to as much as you like. Simply "inherit" from more generic settings using from .. import *, and overrule - see the provided examples. If you'd rather use a "composition" model (import settings not just from base settings "above", but also "from the side"), that's also fine.
This release contains all the relevant shell scripts in the bin directory, and a fully working Django example project in mysite. You can copy files from it as needed to your own projects. To get the example environment working, do the following:
- Copy bin/initenv_example to bin/initenv.
- Edit bin/initenv, set PROJECT_ROOT and save the file.
- Use source bin/initenv to load django-environments into your shell. If you left in the djenv command, you will see the environment settings immediately.
- For fun, you could do a cp -rpv mysite foo from the top directory, followed by djenv foo. Be sure to try out the tab completion.
- For automatic initialization of django-environments when using virtualenv with virtualenvwrapper, you can either source <path-to-project>/bin/initenv from bin/postactivate, or simply use your initenv's contents inside postactivate. Alternatively, you may also symlink bin/postactivate to your initenv script.
If everything works okay, the following shell functions are created:
- djenv (tab completion)
- switch to different settings or another Django project.
- cdroot (tab completion)
- go to current project root.
- cdlib (tab completion)
- go to subdirectory 'lib' of the current project root.
- cdjango (tab completion)
- go to Django project root (one lower than project root).
- djadmin (install tab completion yourself)
- shorthand for django-admin.py, which you should use instead of manage.py (unless you want to tweak things).
- perform django-admin.py runserver <port>, using settings.LOCAL_SERVER_PORT if defined. Use option -p to bind to your network IP address.
- points the browser to the server listening on settings.LOCAL_SERVER_PORT in the current settings.
- Points the browser to the named virtual host for the current settings. Assumes Apache is running as reverse proxy; see bin/create_apache_vhoste_conf.sh for more information.
- pipup (tab completion)
- call pip install with the appropriate file listing the project's requirements.
- remove .pyc files without a corresponding .py.
- remove all empty directories in the project (calls removeorphanpycs first).
- compile all .py files - handy for web server environments, calls removeorphanpycs afterwards.
- get a value from the current settings module, useful for your own scripts (also see the experimental import_django_settings).
- leave the current Django project.
See bin/djenvlib for the more information.
Compatibility with virtualenv
Please note django-environments does not in any way depend on virtualenv, although it can be used together with virtualenv quite well.
When using django-environments within a single virtualenv environment, you can switch between Django projects as often as you like. If you use virtualenvwrapper, use bin/postactivate and bin/predeactivate for calling djenv and djexit respectively.
Compatibility with Python < 2.6
In the example settings files, from .. import * is used. You will need to change this to from <project>.settings import * for older versions of Python. The downside is that you will have to include the project name in your settings, which is a violation of the DRY principle that django-environments tries to live by.
Using Apache mod_wsgi
Should you wish to use the settings in for instance settings/env/staging.py, simply copy the example mysite/deploy/development.wsgi to mysite/deploy/staging.wsgi, or make staging.wsgi a symlink (if your Apache configuration allows it, which is normally the case). Next, add something like this to your httpd.conf:
WSGIScriptAlias / /Users/spanky/repos/django-environments/mysite/deploy/staging.wsgi
And restart Apache. The identifier 'staging' in staging.wsgi will automatically make sure settings.env.staging is used. Create other .wsgi files for other environment settings.
Refer to the source of the provided WSGI script to see how specific directories, like a virtualenv site-packages directory, can be prepended to sys.path, overruling standard Python environment settings.
- The mysite/settings directory replaces settings.py and contains the default settings in generic.py, whose contents are imported in __init__.py.
- The mysite/settings/env directory contains the different settings files for every environment.
- All .wsgi files in the mysite/deploy folder are normally equal, except for the sys.path configuration. Their respective filenames are used to determine which settings to import. If your Apache configuration allows it, you could use symlinks instead of copies.
- The bin directory contains the shell scripts intended to be sourced with the source command, unless they have a '.sh' extension.
- urls.py is just there to demonstrate the SERVE_MEDIA
- setting, which is not essential anyway.
- manage.py is removed as the generated default ignores $DJANGO_SETTINGS_MODULE, simply importing 'settings' instead.
- the Django startapp command will create new apps in $DJANGO_PROJECT/settings/env. Apparently, Django uses the basename of the settings __file__ as a reference point for the new app.