WASI Builder

A Docker-based builder for creating WASI (WebAssembly System Interface) components from Rust source code using the officially supported cargo build --target wasm32-wasip2 toolchain.

Features

• Builds WASI Preview 2 components from Rust crates
• Supports both debug and release modes
• Secure sandboxed build environment
• Reproducible builds with fixed versions
• Multi-architecture support (amd64, arm64)

Development

# Install Task (if not already installed)
curl -sL https://taskfile.dev/install.sh | sh

Configuration

The project uses a .env file for configuration:

# Docker Configuration
ORG=lay3rlabs
IMAGE_NAME=wasi-builder
REGISTRY=ghcr.io
DOCKERFILE=Dockerfile

# Build Tool Versions
RUST_VERSION=1.90-slim-bookworm
WASM_TOOLS_VERSION=1.240.0

Quick Start

# Build the Docker image
task build

# Test the build
task test

Usage

The container automatically detects and builds all Rust components found in the mounted /docker directory. Built WASM files are output to /docker/output.

Container Arguments

entrypoint [COMPONENT_NAME] [--debug]

• COMPONENT_NAME: Build only the specified component package (optional)
• --debug: Build in debug mode (default: release)
• --help: Show usage information

Environment Variables

• COMPONENTS_DIR: Subdirectory within /docker to search for components (optional)
• EXCLUDE_FOLDERS: Comma-separated list of folder names to skip (optional)
• HOST_UID / HOST_GID: Fix output file ownership to these IDs (optional)

Examples

# Build all components in release mode (default)
docker run --rm \
  -v $(pwd)/my-project:/docker \
  -v $(pwd)/output:/docker/output \
  -e HOST_UID=$(id -u) -e HOST_GID=$(id -g) \
  wasi-builder

# Build all components in debug mode
docker run --rm \
  -v $(pwd)/my-project:/docker \
  -v $(pwd)/output:/docker/output \
  -e HOST_UID=$(id -u) -e HOST_GID=$(id -g) \
  wasi-builder --debug

The builder will automatically detect and build:

• Single components
• Cargo workspaces
• Mixed projects with multiple components

Configuration Options

• Target: wasm32-wasip2
• Output: Stripped .wasm component files compatible with WASI Preview 2
• Build Mode: Release (optimized) or Debug
• Permissions: Automatically fixes file ownership for host user access
• WIT Dependencies: Users are responsible for managing their own WIT dependencies

License

This project is part of the Lay3rLabs ecosystem.