FROM scratch AS base
ENV VERSION=1.5.4
ENV SRC_HASH=d75e6960ecfabaaa83a7261b1b630d24e9c63aca79615fb15bf33e11b62fd019
ENV SRC_FILE=v${VERSION}.tar.gz
ENV SRC_SITE=https://github.com/golang/protobuf/archive/refs/tags/${SRC_FILE}

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

FROM fetch AS build
COPY --from=stagex/busybox . /
COPY --from=stagex/go . /
COPY --from=stagex/ca-certificates . /
RUN tar -xvf v${VERSION}.tar.gz
WORKDIR protobuf-${VERSION}
ENV GOPATH=${PWD}/cache/go
ENV GOCACHE=${PWD}/cache/
ENV GOWORK=off
ENV GOPROXY=https://proxy.golang.org,direct
ENV GOSUMDB=sum.golang.org
ENV CGO_ENABLED=0
ENV GOHOSTOS=linux
ENV GOHOSTARCH=amd64
ENV GOFLAGS=-trimpath
RUN mkdir -p ${GOPATH}
RUN go build -o bin/protoc-gen-go ./protoc-gen-go

from build as install
RUN <<-EOF
    set -eux
    mkdir -p /rootfs/usr/bin/
    cp bin/protoc-gen-go /rootfs/usr/bin/
EOF

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