June 20, 2005. The sun is just beginning to set on the San Francisco Bay Area as I stare at my screen in a small office at work. This day started like many others—grab a cup of coffee, hop online and check Hacker News, and then get back to debugging our application’s latest issue.

We’re running an LAMP stack here, with Apache 2.0 serving up pages built on PHP 4.x, which interacts heavily with Python scripts on the backend. These Python scripts handle everything from user authentication to generating dynamic content. We’ve been using Python for about a year now and we love it—Python is just so expressive and easy to work with.

Today’s issue came in as an alert: our login system stopped working. I grab my developer tools, fire up Firefox 0.8 (it’s slow but the latest), and head over to our staging environment. The authentication page looks normal, but when I try to log in, it just fails silently—no errors, no nothing.

I start by checking the Apache logs; nothing there. I then check the Python scripts that handle user authentication. No errors in those either. Time to fire up gdb and attach it to the running Apache process. This is usually a tedious process, but I’ve done this many times before.

After what feels like an eternity, I finally have a stack trace. It looks something like this:

File "/usr/lib/python2.3/site-packages/mysite/auth.py", line 154
    if user is not None:
                            ^
SyntaxError: invalid syntax

Wait, what? Syntax error in Python 2.3? That’s a no-no! I double-check the file and see that there’s indeed an extra space before the # symbol on line 154:

if user is not None:
    # some code here

This was something I added just yesterday, trying to make comments more visible. Now I’m kicking myself for not catching this earlier.

Fixing the issue takes a few minutes, but I spend the rest of the afternoon arguing with my team about best practices. Some are still hung up on hardcoding passwords in our scripts (ick) and others think Python 2.3 is still good enough. I push back gently, pointing out that we need to be more careful and move towards using more modern tools.

Later, as I’m cleaning up the workspace and getting ready for the evening, I can’t help but feel a bit of pride in what we’ve built so far. The transition from Perl scripts to Python has really paid off—our code is cleaner, easier to maintain, and faster than ever.

But back to work tomorrow!

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Debugging issues like this is a constant reminder that even with the best tools and practices, mistakes can happen. But as long as we’re learning and improving, our applications will keep running smoothly.