Securely Manage Environment Variables for Sensitive Data in Python

import os
from dotenv import load_dotenv

# 1. Load environment variables from a .env file (if it exists)
# This should be at the very top of your application's entry point.
load_dotenv()

# 2. Accessing environment variables
# It's good practice to provide default values or check for existence

# Database credentials
DB_HOST = os.getenv('DB_HOST', 'localhost')
DB_PORT = os.getenv('DB_PORT', '5432')
DB_USER = os.getenv('DB_USER', 'myuser')
DB_PASSWORD = os.getenv('DB_PASSWORD') # This one should probably not have a default
DB_NAME = os.getenv('DB_NAME', 'mydatabase')

# API Keys
STRIPE_SECRET_KEY = os.getenv('STRIPE_SECRET_KEY')
GOOGLE_API_KEY = os.getenv('GOOGLE_API_KEY')

# Application specific settings
DEBUG_MODE = os.getenv('DEBUG_MODE', 'False').lower() == 'true'
APP_SECRET_KEY = os.getenv('APP_SECRET_KEY')

# 3. Example of checking for critical variables
if DB_PASSWORD is None:
    print("Warning: DB_PASSWORD environment variable not set!")
    # In a real application, you might raise an error and exit.

if STRIPE_SECRET_KEY is None:
    print("Warning: STRIPE_SECRET_KEY environment variable not set!")

# 4. Using the variables
print(f"
--- Configuration --- ")
print(f"Database Host: {DB_HOST}")
print(f"Database User: {DB_USER}")
print(f"Database Name: {DB_NAME}")
print(f"Stripe Key: {STRIPE_SECRET_KEY[:4]}{'*' * (len(STRIPE_SECRET_KEY) - 4) if STRIPE_SECRET_KEY else 'N/A'}") # Masking part of the key
print(f"Debug Mode: {DEBUG_MODE}")

# Example .env file content (this file should NOT be committed to version control):
# DB_HOST=your_db_host
# DB_PORT=5432
# DB_USER=your_db_user
# DB_PASSWORD=your_super_secret_db_password
# DB_NAME=your_database
# STRIPE_SECRET_KEY=sk_test_xxxxxxxxxxxxxxxxxxxxxx
# GOOGLE_API_KEY=AIzaSyBxxxxxxxxxxxxxxxxxxxxxxxxxxxx
# DEBUG_MODE=True
# APP_SECRET_KEY=a_very_long_and_random_string_for_app_secret