uvtrick.md

uvtrick: Run Python Code from venv in Current Environment

🔗: uvtrick

The following Python code executes the uses_rich function in a fresh Python virtual environment that's...

• managed by uv
• using Python 3.12
• ensuring rich package is installed and available...even if it's not available in the current Python environment

from uvtrick import Env

def uses_rich():
    from rich import print
    print("hi :vampire:")

Env("rich", python="3.12").run(uses_rich)

The trick works by taking advantage of uv's speed to perform the following operations, all within the Env.run() method:

1. Create a new temp directory
2. Pickle the args and kwargs, and save them to pickled_inputs.pickle
3. Use inspect.getsource() to get the source code of the function passed to run()
4. Write that source to a pytemp.py file, along with the genearted if __name__ == "__main__": block responsible for calling the function with pickled inputs, and save its output to a new, separate pickle file named tmp.pickle

Finally, after creating the new temporary Python file, it executes the program using a command similar to:

uv run --with rich --python 3.12 --quiet pytemp.py

Which reads the output from tmp.pickle and returns it to the caller. Sensational.