Before this change, the error would suggest installing buildx:
echo "FROM scratch" | DOCKER_BUILDKIT=0 docker build -
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
Install the buildx component to build images with BuildKit:
https://docs.docker.com/go/buildx/
...
However, this error would also be shown if buildx is actually installed,
but disabled through "DOCKER_BUILDKIT=0";
docker buildx version
github.com/docker/buildx v0.9.1 ed00243
With this patch, it reports that it's disabled, and how to fix:
echo "FROM scratch" | DOCKER_BUILDKIT=0 docker build -
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
BuildKit is currently disabled; enabled it by removing the DOCKER_BUILDKIT=0
environment-variable.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>