dotenv.md

The dotenv Package

Prerequisite: Environment Variables, The os Module

The dotenv package allows a program to reference environment variables from a project-specific ".env" file. This makes environment variables much easier to manage, especially for Windows users.

Reference: https://github.com/theskumar/python-dotenv.

Installation

First install the package, if necessary:

pip install python-dotenv # note: NOT just "dotenv"

Usage

To setup this example, create a new directory on your Desktop named "my-secure-project". Then navigate there from the command-line:

cd Desktop/my-secure-project/

Create two files in the "my-secure-project" directory named ".env" and "my_script.py", respectively, and place inside the following contents:

# my-secure-project/.env

SECRET_MESSAGE="Hello World"

# my-secure-project/my_script.py

from dotenv import load_dotenv
import os

print(os.environ.get("SECRET_MESSAGE")) #> None

load_dotenv() #> loads contents of the .env file into the script's environment

print(os.environ.get("SECRET_MESSAGE")) #> "Hello World"

And run the script to see the output:

python my_script.py

The lesson is that the load_dotenv() function will load environment variables from the ".env" file into the Python script's environment so they can be accessed via the os module.

Ignoring ".env" Files from Version Control

SECURITY NOTE: Because these ".env" files often contain sensative information like secret passwords and API Keys, we should absolutely avoid checking them into version control! To do this, we'll use a special ".gitignore" file.

Create another file in the "my-secure-project" directory named ".gitignore", and place inside the following contents:

# my-secure-project/.gitignore

# ignore the ".env" file:
.env

Great! Now all subsequent commits will ignore the ".env" file from your project's version history, so you can push your code to GitHub without divulging your secret credentials.