paketo-buildpacks
Support for UV package manager
Since Poetry, python packaging has gone through quite a bit of changes, and projects are slowly migrating to new tools. Unfortunately, uv seems to not be supported either natively, or through pip install .
Describe the Enhancement
Currently python projects using uv as a dependency manager don't get properly recognized. There is no buildpack natively supporting uv, and pip-install requires a requirements.txt file that uv doesn't actively manage. Adding support to pip-install for installing projects from pyproject.toml files, and a buildpack specifically for uv-managed projects would be the goal.
Possible Solution
A new buildpack, similar to poetry* family of buildpacks could be made for uv. So, uv to provide uv, uv-install to install packages using uv, and uv-run to set the start command.
Additionally, the pip-install buildpack could also run and install the project if pyproject.toml is detected, and no other package-manager specific buildpack can be run.
Motivation
Currently, projects package managers other than Pipenv and Poetry have to separately manage a requirements.txt file in order to be successfully packaged using these buildpack. Adding fallback support for pyproject.toml to the pip-install could allow these projects to use buildpacks without going through extra steps. Obviously, pm-specific buildpacks should still be implemented, maintained and preferred, if for no other reason than dependency locking.
For anyone who needs uv support, another option is to use Heroku's Python CNB, which added support for uv earlier this month: https://github.com/heroku/buildpacks-python/releases/tag/v2.0.0
The best way to do so would be via Heroku's builder image: heroku/builder:24
More about Heroku's CNBs and builder images can be found here: https://github.com/heroku/buildpacks
