subtext: in my opinion, and for companies (and their users) that want a good balance between protecting their core business with Open Source ideals. Following up to my thoughts on the case for funding Open Source, there is a second topic I want to discuss in more detail: Open Source and commercialization. As our founder likes to say: Open Source is not a business model. And indeed it really isn't. However, this does not mean that Open Source and Open Source licenses aren't a critical consideration for a technology company and a fascinating interconnection between the business model and license ..read more

Both last week at London tech leaders and this week at the Open Source Summit in Vienna I engaged in various discussions about pledging money to Open Source. At Sentry we have been funding our Open Source dependencies for a few years now and we're trying to encourage others to do the same. It’s not an easy ask, of course. One quite memorable point raised was what I would call “accidental spending”. The story goes like this: an engineering team spins up a bunch of Kubernetes machines. As the fleet grows in scale some inefficiencies creep in. To troubleshoot or optimize, additional services such ..read more

Now that uv is rapidly advancing I have started to dive back into making multi-version imports for Python work. The goal here is to enable multiple resolutions from the solver in uv so that two incompatible versions of a library can be installed and used simultaniously. Simplified speaking it should be possible for a library to depend on both pydantic 1.x and 2.x simultaniously. I have not made it work yet, but I have I think found all of the pieces that stand in the way. This post mostly exists to share how it could be done with the least amount of changes to Python. Basic Operation Python's ..read more

As I'm getting older a lot of my social circles are becoming ever more conservative. The focus shifts from building with ambition to fiercly protecting what one has achieved. Shifting the mind on protectionism makes one consider all that can cause damage. It puts the focus on the negative, it makes those negative thoughts feel much more significant than they are and one dwells on the past, instead of envisioning of what opportunity might lie ahead. Yet, when we look back at history, it becomes clear that progress and fresh ideas tend to prevail over time. Not every new idea will succeed, but ..read more

Given that I can't stop creating template engines, I figured I might write a bit about my learnings of creating MiniJinja which is an implementation of my Jinja2 template engine for Rust. Disclaimer: this post might be a bit more technical. There is a good chance you have come across Jinja2 templates before as they became quite common place in various places over the years. They look a bit like this: {% extends "layout.html" %} {% block body %} <p>Hello {{ name }}!</p> {% endblock %} If you want to play around it yourself, here are some links: The MiniJinja playground lets yo ..read more

It has been a few months since I wrote about Rye here last. You might remember that in February I passed over stewardship of my Rye packaging too to Astral. The folks over there have been super busy in building a lot of amazing tooling for Python packaging in the last few months. If you have been using Rye in the last few months you will have noticed that the underlying resolver and installer uv got a lot better and faster. As of the most recent release, uv also gained a lot of functionality that previously required Rye such as manipulating pyproject.toml files, workspace support, local packag ..read more

My colleague Ben Vingar wrote a tool called Counterscale which I would describe as “deploy your own analytics”. Except there is a catch: it needs Cloudflare to run. Is it really self hosted if your only way to deploy it is some proprietary cloud vendor? What's a Stack? Many years ago we talked about software stacks. A common one happened to be “LAMP”. Short for: Linux, Apache, MySQL and typically PHP, though Python and Perl were choices for the P just as well. LAMP lends itself very well for self hosting because all of it is Open Source software you can run and operate yourself free of charge ..read more

This is mostly an FYI for node developers. The issue being discussed in this post has caused us quite a bit of pain. It has to do with how node deals with timeouts. In short: you can very easily create memory leaks [1] with the setTimeout API in node. You're probably familiar with that API since it's one that browsers provide for many, many years. The API is pretty straightforward: you schedule a function to be called later, and you get a token back that can be used to clear the timeout later. In short: const token = setTimeout(() => {}, 100); clearTimeout(token); In the browser the toke ..read more

Given that building programming languages and interpreters is the developer's most favorite hobby, I will never stop writing templating engines. About three years ago I first wanted to see if I can make an implementation of my Jinja2 template engine for Rust. It's called MiniJinja and very close in behavior to Jinja2. Close enought that I have seen people pick it up more than I thought they would. For instance the Hugging Face Text Generation Inference uses it for chat templates. I wrote it primarily just to see how you would introduce dynamic things into a language that doesn't have much of a ..read more

There was a bit of a kerfuffle about subverting open source projects recently. That incident made me think about something that's generally on my mind. That thought again was triggered by that incident but is otherwise not in response to it. I want to talk about some of the stresses of being an Open Source contributor and maintainer but specifically about something that have been unsure over the years about: anonymity and pseudonymity. Over the years it has been pretty clear that some folks are contributing in the Open Source space and don't want to have their name attached to their contributi ..read more