Python Full Stack Web Developer Course

Exercise: Environment Health Check Tool

Let's apply what we've learned by creating a virtual environment "health check" script that you can use to validate your environment setup.

Create a file named env_check.py with the following content:

#!/usr/bin/env python
"""
Virtual Environment Health Check

A utility to verify your virtual environment is properly configured.
"""

import os
import sys
import site
import subprocess
import platform
from pathlib import Path

def header(text):
    """Print a section header."""
    print("\n" + "=" * 60)
    print(f" {text}")
    print("=" * 60)

def check_mark(condition):
    """Return a check mark or X based on condition."""
    return "✅" if condition else "❌"

def main():
    """Run the environment health check."""
    header("VIRTUAL ENVIRONMENT HEALTH CHECK")
    
    # Check if running in a virtual environment
    in_venv = sys.prefix != sys.base_prefix
    print(f"{check_mark(in_venv)} Running in a virtual environment")
    
    if not in_venv:
        print("\n⚠️  WARNING: Not running in a virtual environment!")
        print("    Please activate your virtual environment and try again.")
        print("    Example: source venv/bin/activate")
        sys.exit(1)
    
    # Get environment details
    venv_path = sys.prefix
    python_version = platform.python_version()
    pip_version = subprocess.run(
        [sys.executable, "-m", "pip", "--version"],
        capture_output=True, text=True
    ).stdout.split()[1]
    
    print(f"\nEnvironment path: {venv_path}")
    print(f"Python version: {python_version}")
    print(f"Pip version: {pip_version}")
    
    # Check site-packages location
    site_packages = site.getsitepackages()[0]
    correct_site_packages = Path(site_packages).is_relative_to(Path(venv_path))
    print(f"{check_mark(correct_site_packages)} Site-packages directory: {site_packages}")
    
    # Check activation script
    if os.name == 'nt':  # Windows
        activate_script = Path(venv_path) / "Scripts" / "activate.bat"
    else:  # Unix
        activate_script = Path(venv_path) / "bin" / "activate"
    
    script_exists = activate_script.exists()
    print(f"{check_mark(script_exists)} Activation script: {activate_script}")
    
    # Check for key packages
    header("INSTALLED PACKAGES")
    
    # Get installed packages
    installed_packages = subprocess.run(
        [sys.executable, "-m", "pip", "list"],
        capture_output=True, text=True
    ).stdout.strip().split('\n')[2:]  # Skip header lines
    
    print(f"Total installed packages: {len(installed_packages)}")
    
    # Show top packages (first 10)
    if installed_packages:
        print("\nTop packages:")
        for i, package_line in enumerate(installed_packages[:10]):
            print(f"  {package_line}")
        
        if len(installed_packages) > 10:
            print(f"  ...and {len(installed_packages) - 10} more")
    
    # Check requirements file
    header("PROJECT CONFIGURATION")
    
    # Find requirements files
    req_files = list(Path().glob("requirements*.txt")) + list(Path().glob("requirements/*.txt"))
    if req_files:
        print(f"{check_mark(True)} Found {len(req_files)} requirements files:")
        for req_file in req_files:
            print(f"  - {req_file}")
    else:
        print(f"{check_mark(False)} No requirements files found")
    
    # Check for common environment files
    env_files = list(Path().glob(".env*"))
    if env_files:
        print(f"{check_mark(True)} Found {len(env_files)} environment files:")
        for env_file in env_files:
            print(f"  - {env_file}")
    else:
        print(f"{check_mark(False)} No environment files found")
    
    # Check for .gitignore
    gitignore = Path(".gitignore")
    gitignore_exists = gitignore.exists()
    print(f"{check_mark(gitignore_exists)} .gitignore file")
    
    if gitignore_exists:
        venv_ignored = False
        gitignore_content = gitignore.read_text()
        venv_patterns = ["venv/", "/venv", "venv", "env/", "ENV/"]
        for pattern in venv_patterns:
            if pattern in gitignore_content:
                venv_ignored = True
                break
        print(f"{check_mark(venv_ignored)} Virtual environment ignored in .gitignore")
    
    # Summary
    header("SUMMARY")
    
    if in_venv and correct_site_packages and script_exists:
        print("✅ Your virtual environment appears to be configured correctly!")
    else:
        print("⚠️  Your virtual environment may have issues that need attention.")
    
    if not req_files:
        print("\n⚠️  Recommendation: Create a requirements.txt file to track dependencies.")
    
    if not env_files:
        print("\n⚠️  Recommendation: Consider using .env files for environment variables.")
    
    if gitignore_exists and not venv_ignored:
        print("\n⚠️  Recommendation: Add your virtual environment directory to .gitignore.")
    
    print("\nFor additional checks, consider tools like 'pip-audit' for security vulnerabilities")
    print("or 'pip check' to verify package dependencies.")

if __name__ == "__main__":
    main()

Using the Script

To use this script:

1. Save it as env_check.py in your project directory
2. Activate your virtual environment
3. Run it with python env_check.py

The script will perform several checks on your virtual environment and provide recommendations for improvements.

Script Features

• Verifies you're running in a virtual environment
• Displays key environment information
• Lists installed packages
• Checks for requirements files
• Verifies .gitignore configuration
• Provides recommendations for best practices

This script demonstrates practical application of the virtual environment concepts we've covered, and gives you a tool you can use in future projects.