From bc9708c14d8256ed297006c0a2972e290dbc7759 Mon Sep 17 00:00:00 2001
From: Thomas Ferrandiz <thomas.ferrandiz@suse.com>
Date: Mon, 29 Apr 2024 15:38:31 +0000
Subject: [PATCH] Optimize build-time by using cross-compilation

---
 Dockerfile | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 3aff93a..fa0e5dd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,25 +1,35 @@
 #ARG BCI_IMAGE=registry.suse.com/bci/bci-micro
 ARG GO_IMAGE=rancher/hardened-build-base:v1.21.9b1
+
+# Image that provides cross compilation tooling.
+FROM --platform=$BUILDPLATFORM rancher/mirrored-tonistiigi-xx:1.3.0 as xx
+
 #FROM ${BCI_IMAGE} as bci
-FROM ${GO_IMAGE} as builder
+FROM --platform=$BUILDPLATFORM ${GO_IMAGE} as base-builder
+# copy xx scripts to your build stage
+COPY --from=xx / /
+RUN apk add file make git clang lld 
+ARG TARGETPLATFORM
 # setup required packages
 RUN set -x && \
-    apk --no-cache add \
-    file \
+    xx-apk --no-cache add \
     gcc \
-    git \
+    musl-dev \
+    build-base \
     libselinux-dev \
-    libseccomp-dev \
-    make
+    libseccomp-dev 
+
 # setup the build
+FROM base-builder as metrics-builder
 ARG PKG="github.com/kubernetes-incubator/metrics-server"
 ARG SRC="github.com/kubernetes-sigs/metrics-server"
 ARG TAG=v0.7.1
-ARG ARCH="amd64"
+ARG ARCH
 RUN git clone --depth=1 https://${SRC}.git $GOPATH/src/${PKG}
 WORKDIR $GOPATH/src/${PKG}
 RUN git fetch --all --tags --prune
 RUN git checkout tags/${TAG} -b ${TAG}
+RUN go mod download
 RUN go install -mod=readonly -modfile=scripts/go.mod k8s.io/kube-openapi/cmd/openapi-gen && \
     ${GOPATH}/bin/openapi-gen --logtostderr \
     -i k8s.io/metrics/pkg/apis/metrics/v1beta1,k8s.io/apimachinery/pkg/apis/meta/v1,k8s.io/apimachinery/pkg/api/resource,k8s.io/apimachinery/pkg/version \
@@ -27,19 +37,29 @@ RUN go install -mod=readonly -modfile=scripts/go.mod k8s.io/kube-openapi/cmd/ope
     -O zz_generated.openapi \
     -h $(pwd)/scripts/boilerplate.go.txt \
     -r /dev/null;
-RUN GO_LDFLAGS="-linkmode=external \
+# cross-compilation setup
+ARG TARGETPLATFORM
+RUN xx-go --wrap && \
+    CGO_ENABLED=1 \
+    GO_LDFLAGS="-linkmode=external \
     -X ${PKG}/pkg/version.Version=${TAG} \
     -X ${PKG}/pkg/version.gitCommit=$(git rev-parse HEAD) \
     -X ${PKG}/pkg/version.gitTreeState=clean \
     " \
     go-build-static.sh -gcflags=-trimpath=${GOPATH}/src -o bin/metrics-server ./cmd/metrics-server
 RUN go-assert-static.sh bin/*
+RUN xx-verify --static bin/*
 RUN if [ "${ARCH}" = "amd64" ]; then \
        go-assert-boring.sh bin/*; \
     fi
-RUN install -s bin/* /usr/local/bin
+RUN install bin/metrics-server /usr/local/bin
+
+FROM ${GO_IMAGE} as strip_binary
+#strip needs to run on TARGETPLATFORM, not BUILDPLATFORM
+COPY --from=metrics-builder /usr/local/bin/metrics-server /usr/local/bin
 RUN metrics-server --help
+RUN strip /usr/local/bin/metrics-server
 
 FROM scratch as k8s-metrics-server
-COPY --from=builder /usr/local/bin/metrics-server /
+COPY --from=strip_binary /usr/local/bin/metrics-server /
 ENTRYPOINT ["/metrics-server"]