Emscripten forge

Build wasm/emscripten packages with conda/mamba/boa. This repository consists of recipes for conda packages for emscripten.

Note We removed boa support from this repository. We are now using rattler-build

Note The recipes used in this repository follow the rattler-build recipe format.

Installing Packages

We recommend using micromamba to install packages from this channel.

micromamba create -n my-channel-name \
    --platform=emscripten-wasm32 \
    -c https://repo.mamba.pm/emscripten-forge \
    -c https://repo.mamba.pm/conda-forge \
    --yes \
    python numpy scipy matplotlib

Adding Packages

To add a new package to emscripten-forge, just create a Pull Request in this repository. This PR should add a new folder in the recipe_emscripten folder containing the recipe of your package. A good example recipes is:

regex .

Once the PR is merged, the package is built and uploaded to https://beta.mamba.pm/channels/emscripten-forge

Local Builds

To build a package locally, the easiest way is to use pixi (see /pixi.sh/latest/#installation for installation instructions).

# this only needs to be done once
pixi run setup 
# this builds the package
pixi run build-emscripten-wasm32-pkg recipes/recipes_emscripten/regex

Local Builds with rattler-build

Only recipes with a rattler_recipe.yaml file can be built with rattler-build.

1 Create a new conda environment from ci_env.yml and install playwright in this environment: On a Linux / MacOS this can be done with:

micromamba create -n emscripten-forge -f ci_env.yml --yes
micromamba activate emscripten-forge

All further steps should be executed in this environment. Ie if you open a new terminal, you have to activate the environment again with micromamba activate emscripten-forge.

2 Setup emsdk: We currently need a patched version of emsdk. This is because emscripten had some regressions in the 3.1.45 release wrt. dynamic loading of shared libraries. We use the ./emsdk/setup_emsdk.sh which takes two arguments: the emsdk version and the path where emsdk should be installed. In this example we choose ~/emsdk as the installation path. You have to use version 3.1.45.

./emsdk/setup_emsdk.sh 3.1.45 ~/emsdk

2b Build compiler packages / meta packages :

This is only needed for MacOS. On Linux, the compiler packages are already built and available in the emscripten-forge channel.

rattler-build build --recipe recipes/recipes/emscripten_emscripten-wasm32/rattler_recipe.yaml   -c https://repo.mamba.pm/emscripten-forge -c conda-forge -c microsoft -m conda_build_config.yaml
rattler-build build --recipe recipes/recipes/cross-python_emscripten-wasm32/rattler_recipe.yaml -c https://repo.mamba.pm/emscripten-forge -c conda-forge -c microsoft -m conda_build_config.yaml
rattler-build build --recipe recipes/recipes/pytester/rattler_recipe.yaml                       -c https://repo.mamba.pm/emscripten-forge -c conda-forge -c microsoft -m conda_build_config.yaml

3 Build packages with rattler-build:

rattler-build build  --recipe recipes/recipes_emscripten/regex/rattler_recipe.yaml  --target-platform=emscripten-wasm32 -c https://repo.mamba.pm/emscripten-forge -c conda-forge -c microsoft -m conda_build_config.yaml

Outlook

We are working on:

MambaLite: A wasm compiled version of mamba st. we can install emscripten-forge packages at wasm-runtime.

Credits

This project would not have been possible without the pioneering work of the pyodide team. Many aspects of this project are heavily inspired by the pyodide project. This includes the build scripts and many of the patches which have been taken from the pyodide packages.