Rust

It’s been almost a year since I last posted an update on eugene, the CLI tool I’m building to help people write safer SQL migration scripts for postgres. I announced this tool in Careful with That Lock, Eugene: Part 2. At the time, eugene would execute a single SQL script, recording all the locks acquired and warn about possible downtime due to migrations. It could produce JSON suitable for automated tooling and Markdown suitable for human reading and using in CI comments/checks. That version was already good enough for me to start using in real projects — but it’s improved a lot since then, it’s now easy to run with almost no setup. ...

I’ve been wanting to write this post for a while, about what I think is an elegant way to solve some constraint satisfaction problems. Constraints tend to come up fairly often in real world programs, and some times it can be effective to treat them as constraint satisfaction problems. This post has a bit of background on constraint satisfaction problems I’ve encountered recently, then it goes over to develop Rust code for an algorithm that we can easily use to solve some Advent of Code problems, and we use it to make a solver for sudoku puzzles. Along the way, we explain the syntax we use, it shouldn’t be too hard to understand for someone who is unfamiliar with the language. ...

I’ve been busy working on a documentation site for eugene, and I think it’s starting to look pretty good. I wanted to write down some of my thoughts around the process so far, and some of the things I’ve learned. It’s just been a few days since I ported my blog to hugo, so since I was already feeling like I was up to speed on that, I decided I’d try using it for the eugene documentation too. I experimented with a few different setups around the hugo-book theme, but it ended up feeling like I was having to configure a bit too much for my taste. I think it looked really nice, but the setup felt a bit janky and complicated, with having the submodules and everything in the eugene repo itself. I think my problem here is just that doing this with hugo would require me to learn more about hugo than I’m ready for right now. ...

I have been working quite a bit on picking up dangerous migration patterns in migration scripts over at the eugene repository lately. A major feature I’ve added is syntax tree analysis, so that we can pick up some patterns without having to run the SQL scripts. This isn’t quite as precise as running the scripts, but it’s a lot faster and can catch quite a few common mistakes. So let’s take a look at how it works! ...

A while back, I wrote Careful with That Lock, Eugene about an idea for how to check if a database migration is likely to disturb production. That post came about after having an inspiring chat with a colleague about the advantages of transactional migration scripts and the ability to check the postgres system catalog views before committing a transaction. Over the past few weeks, I’ve been experimenting with this idea to test if I can use it to build valuable safety checks for DDL migrations. Kind of like shellcheck, but for database DDL migrations. ...