5 items tagged “charlie-marsh”
2024
TIL: Using uv to develop Python command-line applications.
I've been increasingly using uv to try out new software (via uvx) and experiment with new ideas, but I hadn't quite figured out the right way to use it for developing my own projects.
It turns out I was missing a few things - in particular the fact that there's no need to use uv pip at all when working with a local development environment, you can get by entirely on uv run (and maybe uv sync --extra test to install test dependencies) with no direct invocations of uv pip at all.
I bounced a few questions off Charlie Marsh and filled in the missing gaps - this TIL shows my new uv-powered process for hacking on Python CLI apps built using Click and my simonw/click-app cookecutter template.
uv under discussion on Mastodon. Jacob Kaplan-Moss kicked off this fascinating conversation about uv on Mastodon recently. It's worth reading the whole thing, which includes input from a whole range of influential Python community members such as Jeff Triplett, Glyph Lefkowitz, Russell Keith-Magee, Seth Michael Larson, Hynek Schlawack, James Bennett and others. (Mastodon is a pretty great place for keeping up with the Python community these days.)
The key theme of the conversation is that, while uv represents a huge set of potential improvements to the Python ecosystem, it comes with additional risks due its attachment to a VC-backed company - and its reliance on Rust rather than Python.
Here are a few comments that stood out to me.
As enthusiastic as I am about the direction uv is going, I haven't adopted them anywhere - because I want very much to understand Astral’s intended business model before I hook my wagon to their tools. It's definitely not clear to me how they're going to stay liquid once the VC money runs out. They could get me onboard in a hot second if they published a "This is what we're planning to charge for" blog post.
As much as I hate VC, [...] FOSS projects flame out all the time too. If Frost loses interest, there’s no PDM anymore. Same for Ofek and Hatch(ling).
I fully expect Astral to flame out and us having to fork/take over—it’s the circle of FOSS. To me uv looks like a genius sting to trick VCs into paying to fix packaging. We’ll be better off either way.
Even in the best case, Rust is more expensive and difficult to maintain, not to mention "non-native" to the average customer here. [...] And the difficulty with VC money here is that it can burn out all the other projects in the ecosystem simultaneously, creating a risk of monoculture, where previously, I think we can say that "monoculture" was the least of Python's packaging concerns.
I don’t think y’all quite grok what uv makes so special due to your seniority. The speed is really cool, but the reason Rust is elemental is that it’s one compiled blob that can be used to bootstrap and maintain a Python development. A blob that will never break because someone upgraded Homebrew, ran pip install or any other creative way people found to fuck up their installations. Python has shown to be a terrible tech to maintain Python.
Just dropping in here to say that corporate capture of the Python ecosystem is the #1 keeps-me-up-at-night subject in my community work, so I watch Astral with interest, even if I'm not yet too worried.
I'm reminded of this note from Armin Ronacher, who created Rye and later donated it to uv maintainers Astral:
However having seen the code and what uv is doing, even in the worst possible future this is a very forkable and maintainable thing. I believe that even in case Astral shuts down or were to do something incredibly dodgy licensing wise, the community would be better off than before uv existed.
I'm currently inclined to agree with Armin and Hynek: while the risk of corporate capture for a crucial aspect of the Python packaging and onboarding ecosystem is a legitimate concern, the amount of progress that has been made here in a relatively short time combined with the open license and quality of the underlying code keeps me optimistic that uv will be a net positive for Python overall.
Update: uv creator Charlie Marsh joined the conversation:
I don't want to charge people money to use our tools, and I don't want to create an incentive structure whereby our open source offerings are competing with any commercial offerings (which is what you see with a lost of hosted-open-source-SaaS business models).
What I want to do is build software that vertically integrates with our open source tools, and sell that software to companies that are already using Ruff, uv, etc. Alternatives to things that companies already pay for today.
An example of what this might look like (we may not do this, but it's helpful to have a concrete example of the strategy) would be something like an enterprise-focused private package registry. A lot of big companies use uv. We spend time talking to them. They all spend money on private package registries, and have issues with them. We could build a private registry that integrates well with uv, and sell it to those companies. [...]
But the core of what I want to do is this: build great tools, hopefully people like them, hopefully they grow, hopefully companies adopt them; then sell software to those companies that represents the natural next thing they need when building with Python. Hopefully we can build something better than the alternatives by playing well with our OSS, and hopefully we are the natural choice if they're already using our OSS.
Docker images using uv’s python (via) Michael Kennedy interviewed uv/Ruff lead Charlie Marsh on his Talk Python podcast, and was inspired to try uv with Talk Python's own infrastructure, a single 8 CPU server running 17 Docker containers (status page here).
The key line they're now using is this:
RUN uv venv --python 3.12.5 /venv
Which downloads the uv selected standalone Python binary for Python 3.12.5 and creates a virtual environment for it at /venv all in one go.
uv: Python packaging in Rust (via) "uv is an extremely fast Python package installer and resolver, written in Rust, and designed as a drop-in replacement for pip and pip-tools workflows."
From Charlie Marsh and Astral, the team behind Ruff, who describe it as a milestone in their pursuit of a "Cargo for Python".
Also in this announcement: Astral are taking over stewardship of Armin Ronacher's Rye packaging tool, another Rust project.
uv is reported to be 8-10x faster than regular pip, increasing to 80-115x faster with a warm global module cache thanks to copy-on-write and hard links on supported filesystems - which saves on disk space too.
It also has a --resolution=lowest option for installing the lowest available version of dependencies - extremely useful for testing, I've been wanting this for my own projects for a while.
Also included: uv venv - a fast tool for creating new virtual environments with no dependency on Python itself.
Sometimes, performance just doesn't matter. If I make some codepath in Ruff 10x faster, but no one ever hits it, I'm sure it could get some likes on Twitter, but the impact on users would be meaningless.
And yet, it's good to care about performance everywhere, even when it doesn't matter. Caring about performance is cultural and contagious. Small wins add up. Small losses add up even more.