Is there a setting similar to the package-mode in poetry?

[pythonweb2]

uv version: 0.3.1
uv platform: linux

Poetry supports what they call operating modes (https://python-poetry.org/docs/basic-usage/#operating-modes), where if you are not planning on publishing your project, you can specify package-mode = false, which only installs the dependencies listed, but does not install the project into the virtual environment.

I was unable to find something like this mentioned in the docs for projects, is it unsupported or perhaps missing from the docs (or perhaps documented somewhere I couldn't see it).

[zanieb]

We don't support this yet, but there's discussion about excluding the project from installation in various issues.

What's your use-case for this? Why does it matter if the project is installed?

[z3z1ma]

This is a blocker, or at the very least annoying. I can workaround with a shim src dir that just has an empty init.

Lots of people may need to manage a bunch of python dependencies outside the context of having a top-level package they themselves are trying to install. Hence why poetry created the package-mode=false. It lets everyone benefit from the lockfile, resolver, and toolchain. A simple example is https://github.com/apache/airflow which has huge adoption and use at large companies -- but there are obv tons of cases where you need to manage libraries that (may) operate in a context independent of a structured python package.

[charliermarsh]

Just to clarify, are you citing Airflow as an example of a project that is not structured as a package? Or an example of something you might use outside of a package?

[z3z1ma]

The latter.

[z3z1ma]

More random data-oriented examples @charliermarsh

https://github.com/dbt-labs/dbt-core
https://github.com/TobikoData/sqlmesh
https://github.com/feast-dev/feast
https://github.com/mlflow/mlflow
https://github.com/dagster-io/dagster
https://github.com/PrefectHQ/prefect
https://github.com/dlt-hub/dlt
https://github.com/meltano/meltano

We can imagine all the AI / ML / data pipeline / automation code (disparate python scripts in a repository, NOT a src application) we'd like to have lockfiles and uv tooling for.

EDIT: for clarity, these are all things a developer may depend on in a repo that is not otherwise structured as a python application itself.

[zanieb]

It sounds like you're looking for a virtual project, which I believe we support if you enumerate everything as a development dependency? As described in https://docs.astral.sh/uv/concepts/workspaces/#workspace-roots

[z3z1ma]

No, as far as I can tell (and I just tried it) you still need a pyproject.toml somewhere in the repo with project defined. If not in the top level explicit root, then in the member(s) of the virtual root?

In all my examples, dbt or sqlmesh being really straightforward ones, you will not have a src directory or anything to install. But still want to manage a graph of dependencies for the repo to operate.

[zanieb]

Worked fine for me? Did you encounter an error?

❯ uv init --virtual
Initialized workspace `example`
❯ uv add --dev httpx
Using Python 3.11.7
Creating virtualenv at: .venv
Resolved 7 packages in 268ms
Prepared 7 packages in 61ms
Installed 7 packages in 13ms
 + anyio==4.4.0
 + certifi==2024.7.4
 + h11==0.14.0
 + httpcore==1.0.5
 + httpx==0.27.0
 + idna==3.7
 + sniffio==1.3.1
❯ uv run python -c "import httpx"
❯ tree .
.
├── README.md
├── pyproject.toml
└── uv.lock

1 directory, 3 files
❯ cat pyproject.toml
[tool.uv]
dev-dependencies = [
    "httpx>=0.27.0",
]
[tool.uv.workspace]
members = []

[pythonweb2]

My use case in particular is a Django application.

In some cases, it may be desired to package a django app, but in most cases, the root project will never be packaged, however a cross platform lockfile is very useful for CI pipelines, and a better workflow than pip in my opinion.

It looks like the virtual project may work, I will take a look into this.

[z3z1ma]

NVM I see, workspace members can be empty.

I am working with an existing project at work and trying to adapt it to uv so trying to grok everything from the docs. While they mention the notion of virtual root, it doesn't really describe in an obvious way that its a way to manage deps for a project which itself has no installable package. Its focused around pyproject.tomls in subdirectories which are themselves valid projects

That worked for me!

Q I suppose. Does this give us a single layer of dependencies? Whereas with the project.dependencies and project.optional-dependencies we would get to delineate combinations of deps.
poetry supports this in the pending PR for PEP 621 support which works fine with package-mode false (which is to say it just doesnt look for or install the package declared by project.name AFAICT.

[z3z1ma]

I'm going to go out on a limb and say, while we can potentially achieve our goal (creating a cross-platform lockfile from pyproject.toml without a src package) with virtual root and empty members -- it seems obtuse if you zoom out. Like an indirect path. It's solely my gut-feel so its fine to push back.

BTW really excited for uv and thanks for all the work, today has been my breaking it in day so pardon finding and banging on this issue. But from a data / ML engineer perspective -- this is an extremely common scenario. :)

[charliermarsh]

Appreciate the kind words :)

Personally I still feel we can do better with what we're calling "virtual" projects. I'm not a big fan of using virtual workspaces to solve this problem. But I'm mostly focusing on correctness issues in the immediate term so we need a bit of time to step back and think about where to improve.

[charliermarsh]

Wrote up an idea here: #6511

[charliermarsh]

This exists now as of v0.4.0!

Projects that omit [build-system] will no longer be built and installed by default. You can also set tool.uv.package to false to control the behavior explicitly, as in:

[tool.uv]
package = false