FROM scratch AS base
ENV VERSION=0.15.0
ENV SRC_FILE=v${VERSION}.tar.gz
ENV SRC_SITE=https://github.com/moby/buildkit/archive/${SRC_FILE}
ENV SRC_HASH=ebf4b82f7379818d8fcfe5c54034e7f93c062c95f663bfd3c2a622583f62a8a4

FROM base AS fetch
ADD --checksum=sha256:${SRC_HASH} ${SRC_SITE} .

FROM fetch AS build
COPY --from=stagex/musl . /
COPY --from=stagex/bash . /
COPY --from=stagex/busybox . /
COPY --from=stagex/go . /
COPY --from=stagex/make . /
COPY --from=stagex/gcc . /
COPY --from=stagex/binutils . /
COPY --from=stagex/pkgconf . /
RUN tar -xf ${SRC_FILE}
ENV GOPROXY=https://proxy.golang.org,direct
ENV GOSUMDB=sum.golang.org
ENV GOPATH=/cache/go
ENV GOBIN=${GOPATH}/bin
ENV PATH=${GOBIN}:${PATH}
WORKDIR /buildkit-${VERSION}
RUN <<-EOF
    set -eux
    mkdir -p out
    go build -v \
        --ldflags=" \
        -w -s -buildid= \
		-X github.com/moby/buildkit/version.Version=${VERSION} \
		-X github.com/moby/buildkit/version.Revision=stagex \
        " \
        -o out/ \
        ./cmd/...
    rm -r docs/reference
EOF

FROM build AS install
RUN <<-EOF
    set -eux
    mkdir -p /rootfs
    install -Dm755 ./out/* -t /rootfs/usr/bin/
EOF

FROM stagex/filesystem AS package
COPY --from=install /rootfs/. /