In real-world projects you will have to deal with multiple environments. You will have at least a local and a production environment, but you could have other environments as well, such as testing or pre-production environments. Some project settings will be common to all environments, but others will have to be overridden per environment. Let's set up project settings for multiple environments while keeping everything neatly organized.

Create a settings/ directory next to the settings.py file of the educa project. Rename the settings.py file to base.py and move it into the new settings/ directory. Create the following additional files inside the setting/ folder so that the new directory looks as follows:

settings/
    __init__.py
    base.py
    local.py
    pro.py

These files are as follows:

• base.py: The base settings file that contains common settings (previously settings.py)
• local.py: Custom settings for your local environment
• pro.py: Custom settings for the production environment

Edit the settings/base.py file and replace the following line:

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

With the following one:

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(os.path.join(__file__, os.pardir))))

We have moved our settings files to a directory one level lower, so we need BASE_DIR to point to the parent directory to be correct. We achieve this by pointing to the parent directory with os.pardir.

Edit the settings/local.py file and add the following lines of code:

from .base import *

DEBUG = True

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}

This is the settings file for our local environment. We import all settings defined in the base.py file and we only define specific settings for this environment. We have copied the DEBUG and DATABASES settings from the base.py file, since these will be set per environment. You can remove the DATABASES and DEBUG settings from the base.py settings file.

Edit the settings/pro.py file and make it look as follows:

from .base import *

DEBUG = False

ADMINS = (
    ('Antonio M', '[email protected]'),
)

ALLOWED_HOSTS = ['*']

DATABASES = {
    'default': {
    }
}

These are the settings for the production environment. Let's take a closer look at each of them:

• DEBUG: Setting DEBUG to False should be mandatory for any production environment. Failing to do so will result in traceback information and sensitive configuration data exposed to everyone.
• ADMINS: When DEBUG is False and a view raises an exception, all information will be sent by email to the people listed in the ADMINS setting. Make sure to replace the name/email tuple with your own information.
• ALLOWED_HOSTS: Django will only allow the hosts included in this list to serve the application. This is a security measure. We include the asterisk symbol * to refer to all hostnames. We will limit the hostnames that can be used for serving the application later.
• DATABASES: We just keep this setting empty. We are going to cover database setup for production hereafter.

We have placed the project settings in a different location than the default settings.py file. You will not be able to execute any commands with the manage.py tool unless you specify the settings module to use. You will need to add a --settings flag when you run management commands from the shell or set a DJANGO_SETTINGS_MODULE environment variable.

Open the shell and run the following command:

export DJANGO_SETTINGS_MODULE=educa.settings.pro

This will set the DJANGO_SETTINGS_MODULE environment variable for the current shell session. If you want to avoid executing this command for each new shell, add this command to your shell's configuration in the .bashrc or .bash_profile files. If you don't set this variable you will have to run management commands, including the --settings flag, as follows:

python manage.py migrate --settings=educa.settings.pro

You have successfully organized settings for handling multiple environments.