Django Cheat Sheet: Keep Credentials Secure with Environment Variables

Tl;DR
Hard coding config values and credentials is convenient but makes your code less secure and less portable. Use environment variables to make your code more secure and easy to deploy in different environments.

Bad:

TWILIO_SECRET_KEY = "iamverysneaky"
twilio_client = Twilio(key=TWILIO_SECRET_KEY)

The problem:
If someone gets access to your code, now they have access to your Twilio account too! Two problems for the price of one!

Good:

from dotenv import load_dotenv

load_dotenv()

twilio_client = Twilio(key=os.getenv("TWILIO_SECRET_KEY"))

If someone gets access to your code, at least your Twilio account (and user data!) is still safe.

To illustrate how this works, we'll move the auto-generated SECRET_KEY value out of settings.py and into an environment variable.

From this:

SECRET_KEY="thisismyunsecuredsecretkey"

To this:

SECRET_KEY=os.getenv("DJANGO_SECRET_KEY")

Do these things:

1. Download the dotenv package.
   

   $ pip install python-dotenv
   

2. Create a file named .env in the same directory as settings.py.
   

   $ touch .env
   

3. Add the .env file to your .gitignore. This is the most important step bc it keeps .env, and thus your secret values, outside of version control/Git.
   

   $ echo .env >> .gitignore
   

4. Add your config values and credentials to .env.
   

   $ echo 'DJANGO_SECRET_KEY="thisismyunsecuredsecretkey"' >> .env
   

5. Import and loados and dotenv into settings.py. This makes the values accessible.
   

   import os
   from dotenv import load_dotenv
   ...
   load_dotenv()
   

6. Replace the original SECRET_KEY value with an environment variable lookup.
   

   SECRET_KEY=os.getenv("DJANGO_SECRET_KEY")
   

7. Profit! By not getting sued by your users for letting their data get stolen. GDPR goodness!

Comments

[Nicola Erario]

How do you manage Boolean with python-dotenv? I mean that ( for example)DEBUG = True or DEBUG = False in .env file are always evaluated as True

[James Timmins]

Yeah, that's an unfortunate drawback of dotenv. There's a couple of things you can do.

1. Explicitly check for a string value. DEBUG = (os.getenv("DEBUG") == 'true')
2. Cast the val to a boolean DEBUG = bool(os.getenv("DEBUG")), and use an empty string to denote a false value DEBUG=''.
3. Use a more fully-featured package like django-environ. There's slightly more configuration required, but if your project has multiple boolean settings it might be worth it. (I haven't actually used django-environ, but it looks pretty interesting so I may investigate).

[Bhupesh Varshney 👾]

thanks for this

[Thomas Güttler]

Don't ask my why the author did not accept my PR: github.com/theskumar/python-dotenv...

Converting types

The library reads and provides strings. If you need for example a boolean, it is up to you to convert the value.

Example:

from distutils.util import strtobool
DEBUG = bool(strtobool(os.getenv('DEBUG', 'True')))

[David Talbot]

This is really helpful, thanks. Agreed—it seems strange that your PR was rejected, given that variables with False values get (confusingly) cast to True.

[eftehassanpp]

Its simple. env always stores string in not only just python but also in javascript. simply parse the env value with json
import json
DEBUG = json.loads(os.getenv("DEBUG"))
if DEBUG:
print("Debugging")

[Ansh Saini]

Okay I'm surprised I didn't know that! Thanks. This'll save me some future headaches.

[Nicola Erario]

Sure! After time spent to True this, False that... and your app lives of it’s own life

[olidroide]

Thanks James! I'm starting using this :) I'm moving from PyCharm to VSCode, and I notice use .env files in VSCode is more easy using "envFile" parameter in launch.json without any plugin and pip pacakge extra.

[pandichef]

I used to do this. Now I just have a mysecrets.py file (which is not in the repo obviously) and just type "from mysecrets import *" at the top of settings.py. The problem I had with .env is with debug mode. Say someone on your team accidentally deploys in prod with DEBUG=True. If an end-user hits a python exception for some reason, the environment variables all appear on the Django debug screen. In contrast, regular python variables in settings.py are obfuscated by Django. Have you noticed this? Does it concern you?

[Samuel Ajibade]

This produces errors when you push your app to heroku for hosting

[Olaniyi Oshunbote]

Were you able to fix this?

[darrentmorgan]

Awesome, thanks!