emsdk

Chainguard Container for emsdk

Allows compilation to WebAssembly using the Emscripten SDK

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/emsdk:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

The emsdk Chainguard Image provides a minimal Emscripten SDK environment for compiling C and C++ code to WebAssembly (Wasm) and JavaScript. Unlike the official emscripten/emsdk Docker image, the Chainguard image runs as a non-root user (emscripten, UID/GID 1000) by default, uses Wolfi as the base operating system instead of Debian, and is built for minimal size and reduced attack surface. The chainguard emsdk image ships with chainguard nodejs, python3, clang, llvm, binaryen. This is reflected in the difference between the configured PATH and upstream.

Included Tools

This image includes:

• emcc - The Emscripten C/C++ compiler
• em++ - The Emscripten C++ compiler
• emsdk - The Emscripten SDK manager
• emar
• emconfigure / emmake - Build system wrappers
• nodejs runtime for executing generated JavaScript

Getting Started

Check the installed Emscripten version:

docker run --rm cgr.dev/chainguard/emsdk emcc --version

Compile a simple C program to JavaScript:

docker run --rm -v $(pwd):/src -w /src cgr.dev/chainguard/emsdk emcc hello.c -o hello.js

Compile to WebAssembly:

docker run --rm -v $(pwd):/src -w /src cgr.dev/chainguard/emsdk emcc hello.c -o hello.wasm

Multi-stage Build Example

Use a multi-stage Dockerfile to compile your application and create a minimal runtime image:

FROM cgr.dev/chainguard/emsdk as build
WORKDIR /src
COPY . .
RUN emcc main.c -o main.js -s WASM=1

FROM cgr.dev/chainguard/nginx
COPY --from=build /src/main.js /src/main.wasm /usr/share/nginx/html/

Documentation and Resources

• Official Emscripten Documentation
• Emscripten SDK GitHub Repository
• WebAssembly MDN Documentation

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.