My desktop ran out of memory five times in two days, once killing 29,082 processes at a stroke. Two files that were each sensible on their own had made a loop with no way out.
Railway's dashboard knows how many requests my app served, but there's nothing for Prometheus to scrape. Turning its per-minute figures into a counter goes wrong three ways.
A slow grid in a Flask app I maintain had an obvious suspect. The biggest cost was Python re-checking 134,000 objects that would never be freed.
I added a small shield badge showing how many months someone had won a challenge. On my own profile, with one win, it said 21. The sample render I had checked it against said 1.
I deployed a Flask app to Railway with SQLite as the only database. Here is why that was the right call, and the five things that actually bite when you do it.
Python's random module is the wrong tool for passwords, and swapping it for secrets is only most of the fix. The shuffle at the end catches people out.
The nicest idea I met while building boot.dev's static site generator: parse inline Markdown by splitting on the delimiter and alternating, and get validation free from the section count.
I wrote fade-out code for explosion particles in a Pygame project, and it looked fine to me for months. It never faded once, and the reason is a quiet rule about how Pygame draws.
The guided version of Asteroids moves the ship directly: press a key, move; release, stop. I wanted it to feel like space, which meant momentum, and momentum turned out to need a compromise.
