ruby.wasm

ruby.wasm is a collection of WebAssembly ports of the CRuby. It enables running Ruby application on browsers, WASI compatible WebAssembly runtimes, and Edge Computing platforms.

npm packages (for JavaScript host environments)

Package	Description	npm
ruby-head-wasm-wasi	HEAD CRuby built on WASI with JS interop support
ruby-head-wasm-emscripten	HEAD CRuby built on Emscripten (not well tested)

Prebuilt binaries

The prebuilt binaries are available at here. A build is a combination of ruby version, profile, and target.

The supported target triples in this repository are:

• wasm32-unknown-wasi
• wasm32-unknown-emscripten

Profiles

Building from source

Dependencies

• wit-bindgen: A language bindings generator for wit used in the npm packages.
• wasi-sdk: For building for WASI target. Set WASI_SDK_PATH environment variable to the directory of wasi-sdk.
• wasi-vfs: A virtual filesystem layer for WASI.
• wasi-preset-args: A tool to preset command-line arguments to a WASI module.
• Emscripten: For building for Emscripten target

It's recommended to build on a Docker container, which installs all dependencies and provides environment variables:

# For building ruby for WASI target
$ docker run -v $(pwd):/src -w /src --rm -it ghcr.io/ruby/ruby.wasm-builder:wasm32-unknown-wasi /bin/bash
# For building ruby for Emscripten target
$ docker run -v $(pwd):/src -w /src --rm -it ghcr.io/ruby/ruby.wasm-builder:wasm32-unknown-emscripten /bin/bash

Then, you can build by rake command. See rake -T for more information.

# Build only a specific combination of ruby version, profile, and target
# Output is in the `rubies` directory
$ rake build:head-wasm32-unknown-wasi-full-js
# Build npm packages and required ruby
$ rake npm:all

Notable Limitations

The current WASI target build does not yet support Thread related APIs. Specifically, WASI does not yet have an API for creating and managing threads yet.

Also there is no support for networking. It is one of the goal of WASI to support networking in the future, but it is not yet implemented.