BuildKit wrapper

This wrapper uses internal buildkit API and enables more customised build process than offered by docker build. It is using containerd for storing outputs (images). Such approach allows importing and exporting contents of build cache layers, which can be useful on distributed build systems.

Usage:

Start buildkit container:

docker run -d --rm --privileged \
  -v /run/buildkit:/run/buildkit
  -v /var/lib/buildkit:/var/lib/buildkit \
  -v /run/containerd:/run/containerd \
  -v /var/lib/containerd:/var/lib/containerd \
  -v /tmp:/tmp \
  --name buildkit moby/buildkit:latest \
  --oci-worker=false --containerd-worker=true

Download and extract buildkit-build

The binary version works on Linux/AMD64 only.

docker create --name buildkit-wrapper korekontrol/buildkit-wrapper
docker cp buildkit-wrapper:/buildkit-build .
docker rm buildkit-wrapper

Build an image

Setup buildkit endpoint configuration:

export BUILDKIT_HOST=tcp://0.0.0.0:1234

For import or export cache, add environmental variables:

export BUILDKIT_LOCAL_CACHE_IMPORT=/tmp/docker-layers
export BUILDKIT_LOCAL_CACHE_EXPORT=/tmp/docker-layers

Run the build:

./buildkit-build -t <image_name> (...)

This process is executed using standalone buildkit, running in a container. It is not the same as building container using buildkit bundled in docker. Note that resulting container will be persisted in local containerd image repository, so it will not be available to docker. If you want to use it in docker, you need to export/import image.

Export containerd image into docker

ctr --namespace buildkit images export - <image_name> \
  | docker image import - <image_name>

Syntax

The syntax of ./buildkit-build should be the same as syntax of docker build. Currently, only limited set of docker build options is supported:

Option	Description
--file <filename>	(required) Path to Dockerfile
--tag <value>	(required) Resulting image name/tag
--build-arg <name>=<value>	Add build argument value
--label <name>=<value>	Add label value
--target <value>	Target name (inside Dockerfile)
--progress <value>	plain, tty or auto

Credits

Adapted by Marek Obuchowicz from KoreKontrol. Repository is a fork of moby/buildkit and is based on examples provided there.

License

APACHE