django-environ with Lists Environment Varibles in .env Files

Issue

django-environ is the Python package that allows you to use Twelve-factor methodology to configure your Django application with environment variables.

It is very usefull package although there are some missing things in the documentation like how we use list as an environment variable?

They got doc for nested list but not for normal/raw list.

One of the main case for using list would be ALLOWED_HOSTS.

Let's assume we have hosts in our settings.py:

# settings.py
...

ALLOWED_HOSTS = [
    "example.com",
    "awesomedomain.com",
    "stagingdomain.com",
    "10.0.0.2",
    "198.162.44.72",
]

How can we move this hardcoded list/array to an .env file and use it with django-environ?

Solution

First add env.list to your settings:

# settings.py
ALLOWED_HOSTS = env.list("ALLOWED_HOSTS")

Then add your hosts with comma separated into .env which located in the root of your project or a proper location;

# .env
...

ALLOWED_HOSTS=example.com,awesomedomain.com,stagingdomain.com,10.0.0.2,198.162.44.72

Extra

Your environment variables file —.env, can be anything and anywhere —.envs/.local, .env.prod, as long as you configure it properly in your settings:

# settings.py
import os

import environ

# Set the project base directory
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Initiate related env class
env = environ.Env()
# Take environment variables from .env.dev file
environ.Env.read_env(os.path.join(BASE_DIR, '.env.dev')

...

All done!