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Uv: Running a script with dependencies

docs.astral.sh

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Re: Uv: Running a script with dependencies

#61

Post by frollogaston »

skissane wrote: post #59
simonw wrote: post #4

The "declaring script dependencies" thing is incredibly useful: https://docs.astral.sh/uv/guides/scripts/#declaring-script-d... # /// script # dependencies = [ # "requests Save that as script.py and you can use "uv run script.py" to run it with the specified dependencies, magically installed into a temporary virtual environment without you having to think about them at all. It's an implementation of Python PEP 723: h…

This is cool, but honestly I wish it was builtin language syntax not a magic comment, magic comments are kind of ugly. Maybe some day… (I realise there are some architectural issues with making it built-in syntax-magic comments are easier for external tools to parse, whereas the Python core has very limited knowledge of packaging and dependencies… still, one of these days…)

Funny how all this time, the only commonly-used import syntax like this was in HTML+JS with the tag.

Re: Uv: Running a script with dependencies

#63

Post by freddie_mercury »

skissane wrote: post #59
simonw wrote: post #4

The "declaring script dependencies" thing is incredibly useful: https://docs.astral.sh/uv/guides/scripts/#declaring-script-d... # /// script # dependencies = [ # "requests Save that as script.py and you can use "uv run script.py" to run it with the specified dependencies, magically installed into a temporary virtual environment without you having to think about them at all. It's an implementation of Python PEP 723: h…

This is cool, but honestly I wish it was builtin language syntax not a magic comment, magic comments are kind of ugly. Maybe some day… (I realise there are some architectural issues with making it built-in syntax-magic comments are easier for external tools to parse, whereas the Python core has very limited knowledge of packaging and dependencies… still, one of these days…)

It IS built-in language syntax. It's defined in the PEP, that's built-in. It's syntax:

"Any Python script may have top-level comment blocks that MUST start with the line # /// TYPE where TYPE determines how to process the content. That is: a single #, followed by a single space, followed by three forward slashes, followed by a single space, followed by the type of metadata. Block MUST end with the line # ///. That is: a single #, followed by a single space, followed by three forward slashes. The TYPE MUST only consist of ASCII letters, numbers and hyphens."

That's the syntax.

Built-in language syntax.

Re: Uv: Running a script with dependencies

#64

Post by freddie_mercury »

do_not_redeem wrote: post #57
indigodaddy wrote: post #54

Earlier quoted context omitted.

But don't you have to only ever run it once to have the deps/venv for subsequent runs?

I don't know if uv garbage collects its cache, but it wouldn't surprise me. Otherwise disk usage would grow indefinitely.

Yes, disk usage grows indefinitely

https://github.com/astral-sh/uv/issues/5731

Re: Uv: Running a script with dependencies

#65

Post by skissane »

freddie_mercury wrote: post #63
skissane wrote: post #59

Earlier quoted context omitted.

This is cool, but honestly I wish it was builtin language syntax not a magic comment, magic comments are kind of ugly. Maybe some day… (I realise there are some architectural issues with making it built-in syntax-magic comments are easier for external tools to parse, whereas the Python core has very limited knowledge of packaging and dependencies… still, one of these days…)

It IS built-in language syntax. It's defined in the PEP, that's built-in. It's syntax: "Any Python script may have top-level comment blocks that MUST start with the line # /// TYPE where TYPE determines how to process the content. That is: a single #, followed by a single space, followed by three forward slashes, followed by a single space, followed by the type of metadata. Block MUST end with the line # ///. That is…

Suppose I have such a begin block without the correct corresponding end block - will Python itself give me a syntax error, or will it just ignore it?

It might be “built-in syntax” from a specification viewpoint, but does CPython itself know anything about it? Does CPython’s parser reject scripts which violate this specification?

And even if CPython does know about it (or comes to do so in the future), the fact that it looks like a comment makes its status as “built-in syntax” non-obvious to the uninitiated

Re: Uv: Running a script with dependencies

#66

Post by om8 »

nomel wrote: post #46
Humphrey wrote: post #9

Oh this looks amazing! I had pretty much stopped using Python for my one-off scripts because of the hassle of dependencies. I can't wait to try this out.

Am I crazy for having my default interactive shell "/bin/env python" point to a virtual environment with all the random dependencies that my one off scripts need, so I can just run "python oneoneoff.py"? All of my one off scripts combined use maybe a dozen dependencies. If I need more, I just install them there. I use pyenv, so it's trivial to change the version of python that the interactive shell uses (default or t…

What would you do if some of the deps started to have conflicts in them? Also, what are your plans for migration when you'll need to move from one os version to another?

Implicit solutions like yours have lower cost of entrance, but larger cost of support. uv python scripts just work if you set them up once

Re: Uv: Running a script with dependencies

#67

Post by HellsMaddy »

slt2021 wrote: post #24
simonw wrote: post #4

The "declaring script dependencies" thing is incredibly useful: https://docs.astral.sh/uv/guides/scripts/#declaring-script-d... # /// script # dependencies = [ # "requests Save that as script.py and you can use "uv run script.py" to run it with the specified dependencies, magically installed into a temporary virtual environment without you having to think about them at all. It's an implementation of Python PEP 723: h…

shebang mode is also incredibly useful and allows execution like ./script.sh #!/usr/bin/env -S uv run --script # /// script # dependencies = [ # "requests

I really love this and I've been using it a lot. The one thing I'm unsure about is the best way to get my LSP working with inline dependencies.

Usually, when I use uv along with a pyproject.toml, I'll activate the venv before starting neovim, and then my LSP (basedpyright) is aware of the dependencies and it all just works. But with inline dependencies, I'm not sure what the best way to do this is.

I usually end up just manually creating a venv with the dependencies so I can edit inside of it, but then I run the script using the shebang/inline dependencies when I'm done developing it.

Re: Uv: Running a script with dependencies

#68

Post by sa-code »

slt2021 wrote: post #24
simonw wrote: post #4

The "declaring script dependencies" thing is incredibly useful: https://docs.astral.sh/uv/guides/scripts/#declaring-script-d... # /// script # dependencies = [ # "requests Save that as script.py and you can use "uv run script.py" to run it with the specified dependencies, magically installed into a temporary virtual environment without you having to think about them at all. It's an implementation of Python PEP 723: h…

shebang mode is also incredibly useful and allows execution like ./script.sh #!/usr/bin/env -S uv run --script # /// script # dependencies = [ # "requests

This was my contribution to their docs, happy to see people find it useful :)

Re: Uv: Running a script with dependencies

#69

Post by bananapub »

bb88 wrote: post #35
Humphrey wrote: post #9

Oh this looks amazing! I had pretty much stopped using Python for my one-off scripts because of the hassle of dependencies. I can't wait to try this out.

I've played with it for a while now, and for one off scripts where python might make more sense than bash, e.g., I write the script this way with uv, and then I only need uv and the script. One of the complaints about python is that a script stops working over time (because the python installation changes with os updates), and this kinda sorta doesn't make it go away entirely, but what it does do is to eliminate a bu…

> this kinda sorta doesn't make it go away entirely

it absolutely can, `uv` can also pin the python interpreter it uses with `requires-python = "==3.11"` or whatever.

Re: Uv: Running a script with dependencies

#70

Post by CraigJPerry »

HellsMaddy wrote: post #67
slt2021 wrote: post #24

Earlier quoted context omitted.

shebang mode is also incredibly useful and allows execution like ./script.sh #!/usr/bin/env -S uv run --script # /// script # dependencies = [ # "requests

I really love this and I've been using it a lot. The one thing I'm unsure about is the best way to get my LSP working with inline dependencies. Usually, when I use uv along with a pyproject.toml, I'll activate the venv before starting neovim, and then my LSP (basedpyright) is aware of the dependencies and it all just works. But with inline dependencies, I'm not sure what the best way to do this is. I usually end up j…

Yeah i don't think there is a neater way to do this right now. One thing that maybe saves some effort is a "uv sync" will pay attention to the $VIRTUAL_ENV env var, but only if that var points to a venv that already exists. You can't point to an empty dir and have it create the venv.

  # make a venv somehow, probably via the editor so it knows about the venv, saving a 3rd step to tell it which venv to use
  $ env VIRTUAL_ENV=.venv/ uv sync --script foo.py
but it's still janky, not sure it saves much mental tax
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