Demo multi-arch Docker manifest merge with a local registry

manifest-merge

#!/usr/bin/env bash
set -euo pipefail

REGISTRY="${REGISTRY:-localhost:5000}"
IMAGE="${IMAGE:-core}"
VERSION="${VERSION:-noble}"
TAG="${TAG:-test}"
LOGDIR=$(mktemp -d)

RESULT="FAILED"
cleanup() {
  echo "==> Stopping local registry"
  docker stop registry &>/dev/null || true
  rm -rf "$LOGDIR"
  echo "==> ${RESULT}"
}
trap cleanup EXIT

echo "==> Starting local registry"
if docker ps -a --format '{{.Names}}' | grep -q '^registry$'; then
  docker start registry &>/dev/null
else
  docker run -d -p 5000:5000 --name registry registry:2 &>/dev/null
fi
sleep 2

echo "==> Building ${IMAGE}:${VERSION} for both platforms in parallel"
echo "    Logs: ${LOGDIR}/{amd64,arm64}.log"

docker buildx build --platform linux/amd64 -t "${REGISTRY}/${IMAGE}:${TAG}-amd64" --push "${IMAGE}/${VERSION}" \
  > "${LOGDIR}/amd64.log" 2>&1 &
pid_amd64=$!

docker buildx build --platform linux/arm64 -t "${REGISTRY}/${IMAGE}:${TAG}-arm64" --push "${IMAGE}/${VERSION}" \
  > "${LOGDIR}/arm64.log" 2>&1 &
pid_arm64=$!

echo "==> Waiting for builds (amd64: $pid_amd64, arm64: $pid_arm64)"
amd64_ok=0; arm64_ok=0
wait $pid_amd64 && amd64_ok=1 || true
wait $pid_arm64 && arm64_ok=1 || true

if [[ $amd64_ok -eq 0 ]]; then
  echo "==> amd64 build failed:"
  tail -20 "${LOGDIR}/amd64.log"
fi
if [[ $arm64_ok -eq 0 ]]; then
  echo "==> arm64 build failed:"
  tail -20 "${LOGDIR}/arm64.log"
fi
if [[ $amd64_ok -eq 0 || $arm64_ok -eq 0 ]]; then
  echo "==> FAILED"
  exit 1
fi

echo "==> Creating multi-arch manifest"
docker buildx imagetools create -t "${REGISTRY}/${IMAGE}:${TAG}" \
  "${REGISTRY}/${IMAGE}:${TAG}-amd64" \
  "${REGISTRY}/${IMAGE}:${TAG}-arm64"

echo "==> Inspecting manifest"
docker buildx imagetools inspect "${REGISTRY}/${IMAGE}:${TAG}"

RESULT="SUCCESS"