exodide 0.0.4

build_ext for Pyodide

exodide: build_ext for Pyodide

1. Overview

Warning This project is still under development.

Pyodide is a WebAssembly variant of CPython. By using it, we can run Python code inside web browser.

Although we can run most of pure-Python packages on Pyodide, however, available C/C++-extension packages are limited to builtin packages.

The motivation of this project (exodide) is providing C/C++-extension builder for Pyodide, and enables users to run your own custom C/C++-extension packages on Pyodide.

2. Usage

2.1 Prerequest

To build C/C++ to WebAssembly, you need Emscripten. We assume you set up emcc and em++ commands as the official document.

Since Pyodide is built with Python 3.10, we only prepare headers for the version. Your custom package must run on Python 3.10.

2.2 Build with exodide

from setuptools import setup
from exodide import build

# omit

setup(
    # omit
    cmdclass=build.cmdclass(), # {'build': exodide.build, 'build_ext': exodide.build_ext}
)

then CC=emcc CXX=em++ python setup.py bdist_wheel.

Pyodide doesn't provide all the functionalities of CPython, so that you might need to modify your package. You can detect Emscripten compiler by __EMSCRIPTEN__ macro (ref).

#ifdef __EMSCRIPTEN__
// Code for Pyodide
#else
// Code for Others
#endif

2.3 Install to Pyodide

const pyodide = await loadPyodide();

await pyodide.runPythonAsync(`
import micropip
micropip.install("exodide")

from exodide.install import fetch_install

await fetch_install("example.com/your-package.whl")

import your_package
# omit
`);

2.4 Inspect Shared Object (for Debugging)

python3 -m exodide.inspect your-package/your-module.so

Currently, exodide.inspect module prints dylink / dylink.0 custom section, which are used for metadata of Wasm dynamic link.

3. LICENSEs

We utilize other projects and these codes obey their original lisences. We distribute patched header files of CPython and NumPy, too.

• CPython: https://www.python.org/
  • cpython directory
  • PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
• NumPy: https://numpy.org/
  • numpy directory and script/code_generators directory
  • BSD 3-Clause
• Pyodide: https://pyodide.org/en/stable/
  • pyodide directory
  • MPL-2.0
• Others (exodide original codes)
  • MIT

4. Build exodide

git clone --recursive --depth 1 https://github.com/ymd-h/exodide.git
cd exodide

make

pip install .