Technology Tales

Avoiding Python missing package errors with automatic installation checks

Published on 20^th October 2025 Estimated Reading Time: 2 minutes

Though some may not like having something preceding package import statements in Python scripts, I prefer the added robustness of an extra piece of code checking for package presence and installing anything that is missing in place getting an error. In what follows, I define the list of packages that need to be present for everything to work:

required_packages = ["pandas", "tqdm", "progressbar2", "sqlalchemy", "pymysql"]

Then, I declare the inbuilt modules in advance of looping through the list that was already defined (adding special handling for a case where there has been a name change):

import subprocess
import sys
for package in required_packages:
    try:
        __import__(package if package != "progressbar2" else "progressbar")
        print(f"{package} is already installed.")
    except ImportError:
        print(f"{package} not found. Installing...")
        subprocess.check_call([sys.executable, "-m", "pip", "install", package])

The above code tries importing the package and catches the error to do the required installation. While a stable environment may be a better way around all of this, I find that this way of working adds valuable robustness to a script and automates what you would need to do anyway. Though the use of requirements files and even the Poetry tool for dependency management may be next steps, this approach suffices for my simpler needs, at least when it comes to personal projects.