Install WASI SDK GitHub Action

This is a custom GitHub Action for use in your workflows that will install the WASI SDK toolchain for WebAssembly development.

Features

• ✅ Downloads and installs the specified version of WASI SDK
• ✅ Optionally adds WASI SDK to PATH
• ✅ Sets up convenient environment variables
• ✅ Provides output variables for use in subsequent steps
• ✅ Comprehensive error handling and logging

Why Linux Only?

Use runs-on: ubuntu-latest (which is the default) for your workflows that need WASI SDK.

WASI SDK compiles C/C++ code to WebAssembly, which is completely cross-platform. There's no need to install WASI SDK on multiple platforms - you can compile your WebAssembly modules on Linux and run them anywhere. This approach:

• Simplifies CI/CD pipelines
• Reduces complexity and potential issues
• Leverages Linux's excellent toolchain support
• Produces identical WebAssembly output regardless of build platform
• If you want to use it with Windows runners, no prob, you will just need to use it's output.

Usage

Basic Usage

- name: Install WASI SDK
  uses: konsumer/install-wasi-sdk@v1

Advanced Usage

- name: Install WASI SDK
  uses: konsumer/install-wasi-sdk@v1
  with:
    version: "25"
    install-path: "/opt/wasi-sdk"
    add-to-path: "true"

Complete Workflow Example

name: Build WebAssembly with WASI SDK

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Install WASI SDK
        uses: konsumer/install-wasi-sdk@v1
        with:
          version: "25"

      - name: Build WebAssembly module
        run: |
          clang hello.c -o hello.wasm
          # or using the environment variable
          $CC hello.c -o hello.wasm

Inputs

Input	Description	Required	Default
version	WASI SDK version to install (e.g., "25", "24", "23")	No	latest
install-path	Directory to install WASI SDK to	No	/opt/wasi-sdk
add-to-path	Add WASI SDK bin directory to PATH	No	true

Outputs

Output	Description
wasi-sdk-path	Path to the installed WASI SDK
wasi-sdk-version	Version of WASI SDK that was installed
clang-path	Path to the clang executable
sysroot-path	Path to the WASI sysroot

Environment Variables

When add-to-path is true, the action sets up the following environment variables:

• WASI_SDK_PATH: Path to the WASI SDK installation
• CC: Clang compiler with WASI sysroot configured
• CXX: Clang++ compiler with WASI sysroot configured

Version Support

• latest: Automatically installs the latest available version
• Specific versions: 25, 24, 23, 22, etc.

You can find all available versions on the WASI SDK releases page.

Examples

Using Outputs

- name: Install WASI SDK
  id: wasi-sdk
  uses: konsumer/install-wasi-sdk@v1
  with:
    version: "25"

- name: Show installation details
  run: |
    echo "WASI SDK installed at: ${{ steps.wasi-sdk.outputs.wasi-sdk-path }}"
    echo "WASI SDK version: ${{ steps.wasi-sdk.outputs.wasi-sdk-version }}"
    echo "Clang path: ${{ steps.wasi-sdk.outputs.clang-path }}"
    echo "Sysroot path: ${{ steps.wasi-sdk.outputs.sysroot-path }}"

Building C/C++ for WebAssembly

- name: Install WASI SDK
  uses: konsumer/install-wasi-sdk@v1

- name: Build C program
  run: clang -o program.wasm program.c

- name: Build C++ program
  run: clang++ -o program.wasm program.cpp -fno-exceptions

Using with CMake

- name: Install WASI SDK
  uses: konsumer/install-wasi-sdk@v1
  with:
    version: "25"

- name: Configure CMake
  run: |
    cmake -B build \
      -DCMAKE_TOOLCHAIN_FILE=$WASI_SDK_PATH/share/cmake/wasi-sdk.cmake \
      -DCMAKE_BUILD_TYPE=Release

- name: Build with CMake
  run: cmake --build build

Matrix Build for Multiple Versions

strategy:
  matrix:
    wasi-sdk-version:
      - 23
      - 24
      - 25

steps:
  - name: Install WASI SDK
    uses: konsumer/install-wasi-sdk@v1
    with:
      version: ${{ matrix.wasi-sdk-version }}

Troubleshooting

Common Issues

1. Download fails: Check if the specified version exists on the releases page
2. Permission denied: Make sure the runner has write permissions to the install path
3. Platform not supported: This action only supports Linux runners. Use runs-on: ubuntu-latest

Debug Information

The action provides detailed logging. Check the action logs for:

• Platform detection results
• Download URLs
• Installation paths
• Verification results

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Related Projects

• WASI SDK - The official WASI SDK
• wasi-libc - WASI libc implementation uused in wasi-sdk
• Wasmtime - WebAssembly runtime