wasmpy-build

This tool can compile CPython C extension files, such as the ones created by Cython, to WebAssembly so that the extensions are platform independent.

Currently supports CPython 3.6 to 3.12.

wasi-sdk is automatically downloaded on first use.

Usage

Wasmpy-build can be easily integrated into an existing project by the use of a drop-in build_ext override:

From a pyproject.toml file

This uses an experimental feature and may not work verbatim in the future.

[build-system]
requires = ["setuptools", "wasmpy-build"]
build-backend = "setuptools.build_meta"

[project]
# ...

[tool.setuptools.cmdclass]
build_ext = "wasmpy_build.build_ext"

[[tool.setuptools.ext-modules]]
name = "mymodule"
sources = ["mymodule.c"]

From a setup.py script

from wasmpy_build import build_ext
from setuptools import setup, Extension

setup(
    ext_modules=[Extension("mymodule", ["mymodule.c"])],
    cmdclass={"build_ext": build_ext},
)

This also works with generated sources, like from Cython:

from Cython.Build import cythonize
from wasmpy_build import build_ext
from setuptools import setup, Extension

setup(
    ext_modules=cythonize([
        Extension("mymodule", ["mymodule.pyx"])
    ]),
    cmdclass={"build_ext": build_ext},
)

From the command line

C

wasmpy-build my_file.c -o my_file.wasm

C++

wasmpy-build++ my_file.cpp -o my_file.wasm

or

wasmpy-build-cpp my_file.cpp -o my_file.wasm

Installation

Install with pip

pip install wasmpy-build

Build from source

git clone --recurse-submodules https://github.com/olivi-r/wasmpy-build
cd wasmpy-build
python generate.py
python -m pip install .