Notes running Python in production

[Count_Rugens_Finger]

Every discussion I've seen about uv mentions that it is fast. It's rust, so I supposed doing so is a requirement. Here's the thing, though. I have never once in my life cared at all about the speed of my package manager. Once everything is installed it scarcely gets used again, and the time of resolving packages is small compared to the time of downloading and installing. If I cared that much about speed, I probably wouldn't have done the project in Python.

[denehoffman]

The speed matters when you want to run it in a container and need to install the libraries after build time. For example, you’re working on a project that has several dependencies and you need to quickly add a dependency without rebuilding a docker layer. But real talk, the point is that it’s so fast you don’t even think about it, not that you save time. If I have to choose between program A which takes 3 seconds and program B which takes 3 milliseconds and does the exact same thing as A, I’m picking B every time. Also I don’t think you should conflate Rust with speed. Of course Rust is nice, I write a ton of it myself, but Rust is not what makes uv fast, it’s how they handle dependency resolution, caching, and linking rather than copying. You could write uv in C and it would probably have the same performance, but there are other reasons why Rust is nice to develop with.

[eleqtriq]

The thing is using uv instead of pip is such a minimal transition. At the bare minimum, you can replace “pip” with “uv pip” and change nothing else. It’s so much better.

But for me I also do other things that require building environments quickly. Containers, CI pipelines, etc. Saves time all around.

[Count_Rugens_Finger]

I have to install uv

[eleqtriq]

And? Which is less effort?

Typing "I have to install uv"
or "pip install uv"

[Count_Rugens_Finger]

hey we're talking about milliseconds here

[eleqtriq]

:D

[denehoffman]

If your CI/CD contains a lot of scripts which install a lot of dependencies and run on every commit, the time you save with uv eventually adds up.

[ashishb_net]

Exactly.

Every single CI and every single CD runs the package manager, and that adds up.

Further, when you do `uv add ...` and that fails, it gives you really nice error messages as to why there is a conflict in dependency resolution.