Uv: Running a script with dependencies • Hacker News Board

Re: Uv: Running a script with dependencies

#171

Post by willlma » Wed, Jul 23, 2025, 6:56 PM UTC

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…

I'm not a Python dev, but had to write a script the other day and got all cought up with the virtual env stuff. Why can't `uv` just infer the dependencies from the `import ...` line? Why declare the dependencies twice?

Re: Uv: Running a script with dependencies

#172

Post by clayhacks » Wed, Jul 23, 2025, 7:22 PM UTC

willlma wrote: post #171

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…

I'm not a Python dev, but had to write a script the other day and got all cought up with the virtual env stuff. Why can't `uv` just infer the dependencies from the `import ...` line? Why declare the dependencies twice?

Python import names are not necessarily unique or the name of the package on pypi/pip. Something like PyYaml is imported as yaml, but potentially other packages could supply a slightly different yaml to import

Re: Uv: Running a script with dependencies

#173

Post by jasonm23 » Thu, Jul 24, 2025, 1:48 PM UTC

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…

Most _current_ LLMs know about PEP 723, but you have to say "PEP 723" for them to do it properly.

Re: Uv: Running a script with dependencies

#174

Post by sc077y » Thu, Jul 31, 2025, 3:24 AM UTC

Hackbraten wrote: post #133

sc077y wrote: post #131

Earlier quoted context omitted.

By default it will create hard links for python packages, so it won't consume any more memory (besides the small overhead of hard links).

Unless it can't because you happen to have mounted your user cache directory from a different volume in an attempt to debloat your hourly backups.

In that case, you use copy OR what you can can also do, if you really care about disk usage, is use symbolic links between the drives. have a .venv sym link on drive A (raid 1) point to the uv_cache_dir's venv on drive B (raid 0). I have not tested though what happens when you unmount and sync.