Courgette Builder

Google Chrome uses a binary patching tool called Courgette to provide efficient software updates. The technology is described here:

https://www.chromium.org/developers/design-documents/software-updates-courgette

Courgette lives inside the Chromium repository and must be compiled using the complex Chromium build system. It is not offered as an official standalone installable package.

This repository contains a build script that automates the process of compiling Courgette.

Prebuilt packages may be found on the release page, but these are not kept up to date.

Debian and macOS

Please follow the platform-specific guides on building Chromium to install the initial dependencies such as git.

The build script handles the rest:

./build.sh ./workspace

This produces a binary at ./workspace/chromium/src/out/Default/courgette.

It also produces a Debian package at ./workspace/courgette-linux_{version}-{date}+{revision}_{arch}.deb for Linux builds, or a similarly-named zip archive for macOS builds.

Use ldd (Linux) or otool -L (macOS) to view which shared libraries that Courgette links against, such as libbase and libc++.

Debian, using a Docker container

You can construct a Docker container with all of the build dependencies ready to go:

./build.sh ./workspace fetch-only
cp ./workspace/chromium/src/build/install-build-deps.sh .
docker build -t courgette-build .

To execute a build inside the container, run:

docker run -v "$(pwd)/workspace:/ws" courgette-build

macOS host notes

• Docker makes a copy of the entire directory while building a container image. The .dockerignore file is configured to exclude ./workspace, as a checkout of Chromium sources can easily exceed 10GB. If you use another workspace name, it is strongly advised to place it outside of this directory.

• Using the same workspace for macOS and Docker-based Debian builds is currently not possible. It may be possible to clone a workspace created with the fetch-only option before any further steps have been applied:

  ./build.sh ./workspace fetch-only
  cp -ca workspace workspace-linux