Docker Containers

Why!?!

To support multiple Sketch sessions in parallel, and to give the sessions isolation, each Sketch session runs in its own container. (At the end of the day, the output of a Sketch session is new git commit(s).)

Customization

Customizing Sketch's containers

By default, Sketch uses a Docker container generated by https://github.com/boldsoftware/sketch/blob/main/dockerimg/Dockerfile.base and published to https://github.com/boldsoftware/sketch/pkgs/container/sketch. This container is based on Ubuntu 24.04 and contains many popular tools. Sketch will install additional tools as it needs.

Locally, Sketch creates a container image based on the default that includes your working tree. This image is cached (identified by a container label that is a hash of your working tree directory and the base image id) to speed up starting up Sketch. (Future invocations do a "git reset" inside the image, but don't need to copy over the whole git repo.) You can force re-creation with the -force-rebuild-container flag.

If you'd like to customize the container, specify -base-image and point Sketch to an image you've built. We recommend layering your customizations on top of our base image, but this is not strictly necessary. Sketch will then add your repo on top of it, at runtime.

For example, if you want to add Node 22, you might create a Dockerfile like below, and build it with docker build -t sketch-with-node-22 - < Dockerfile.sketch, and pass it to sketch with -base-image sketch-with-node-22.

FROM ghcr.io/boldsoftware/sketch:latest

RUN apt-get update && \
    apt-get install -y curl && \
    curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
    apt-get install -y nodejs && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

Troubleshooting

"no space left on device"

docker system prune -a removes stopped containers and unused images, which usually frees up significant disk space.