Python + WASI with Nix

This is an attempt at using Nix to create a local development environment for the WASI build of Python.

Try it out

Assuming you already have Nix installed with flakes enabled.

1. Clone the repo

   $ git clone https://github.com/alcarney/python-wasi-nix
   $ cd python-wasi-nix
   

2. Activate the devShell

   $ nix develop
   

3. Run the script

   $ python main.py
   sys.platform='wasi'
   {'line': 1, 'character': 42}
   

Resources

• Setting up a Python WASI Environment with Nix: The blog post outlining how the Nix parts of this repo work
• Testing a Python project using the WASI build of CPython with pytest: The blog post that covers the Python + WASI part of this repo
• WebAssembly and its platform targets: Overview of the different WebAssembly runtimes

TODO

This is "good enough" for me to start hacking on the WASI runtime, but there's certainly plenty that could potnetially be improved.

• Building Python WASI from source
• Automatically choosing the right Python package set to use with mkPythonWASIShell, like python.withPackages
• Extending mkPythonWASIShell to allow the user to set the permissions for the Python process
• Overriding a base python derivation so that packages are built against this version of Python.
• Extending this to work with packages that contain native modules?