Environment variables are a fundamental aspect of development in Python, especially when it comes to ensuring your applications follow the twelve-factor app methodology for building software-as-a-service apps. A key principle of this methodology is storing configuration in the environment. Using environment variables in this way separates config from code, a requirement for app deployment on various platforms like Heroku, AWS or Google Cloud. Furthermore, it helps in maintaining security, scalability, and manageability.
In the realm of Python development, setting, retrieving, and using environment variables can be handled with simplicity. In this article, we delve into the details, providing a comprehensive understanding and practical solutions for applying environment variables.
Managing Python Environment Variables
Environment variables in Python can be accessed via the os module, particularly using its os.environ object which is a dictionary-like object that allows access to the underlying environment variables set on the system.
import os
db_user = os.environ.get('DB_USER')
db_password = os.environ.get('DB_PASSWORD')
Here, we retrieve the DB_USER and DB_PASSWORD environment variables.
Setting Environment Variables
Environment variables are usually set in the system, specifically in the terminal environment on Unix and Unix-like systems. For instance, setting the DB_USER variable could be done as follows:
export DB_USER="myDatabaseUser"
However, in Python development, it’s common to set these in a file (like .env).
Practical Walkthrough: Python-dotenv Library
Python-dotenv library allows us to read from a .env file where we can conveniently store our environment variables. This is typically preferable to defining variables in the system as it’s easier to manage application-specific configurations and allows for secure storage of sensitive information such as API keys.
Using python-dotenv, we can write our environment variables in .env file the same way we would in the system.
DB_USER="myDatabaseUser" DB_PASSWORD="superSecurePassword"
To set up the Python dotenv to retrieve these variables, we need to install the python-dotenv library and import it into the Python file.
pip install python-dotenv
You can now load your environment variables from your .env file
import os
from dotenv import load_dotenv
load_dotenv() # take environment variables from .env
db_user = os.getenv('DB_USER')
db_password = os.getenv('DB_PASSWORD')
This approach provides a secure and convenient way to manage your environment variables, maximizing code portability and scalability.
Importance of Managing Environment Variables
Properly managing environment variables leads to more secure, scalable, and manageable applications. Environment variables separate the config from code, which is paramount for cloud-based applications. They allow you to set critical data such as database details and API keys, without exposing sensitive details to your code base.
- Security: Hide sensitive data such as database credentials, API keys, and other secrets.
- Scalability: Manage configurations across various environments: local, production, staging, etc.
- Manageability: Smoother deployments, especially in cloud-based platforms, which rely extensively on environment configurations.
By harnessing the power of environment variables combined with Python, your applications can achieve a whole new level of efficiency and security.
