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Build an image for every Alpine-supported architecture (#212)
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‎.github/workflows/build-test-push.yml‎

Lines changed: 92 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -53,7 +53,7 @@ jobs:
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setup:
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runs-on: ubuntu-latest
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outputs:
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# build job's matrix: cross product of selected directories and platforms
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# build job's matrix: flat include list, one entry per (directory, arch)
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build_matrix: ${{ steps.select.outputs.build_matrix }}
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# merge job's matrix: selected directories only (one manifest list per directory)
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merge_matrix: ${{ steps.select.outputs.merge_matrix }}
@@ -62,6 +62,11 @@ jobs:
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steps:
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- uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
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# Needed for `docker buildx imagetools inspect` to read the Alpine base and
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# published-tag manifests when detecting architectures.
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- name: Set up Docker Buildx
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uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4
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- name: Detect changed directories
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uses: dorny/paths-filter@7b450fff21473bca461d4b92ce414b9d0420d706 # v4
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id: filter
@@ -93,35 +98,94 @@ jobs:
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{"directory": "2.1", "version": "2.1.0", "tags": "2.1 2.1-alpine 2 2-alpine latest"}
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]
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run: |
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SELECTED='[]'
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# Each platform builds on the closest runner architecture to minimize QEMU
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# emulation: amd64 (and 386, which x86-64 runs in hardware) on amd64, and the
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# arm variants on ARM hosts (arm64v8 natively; armv7/armv6 via aarch32 emulation).
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# The remaining arches (ppc64le, s390x, riscv64) have no native runner and are
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# fully emulated.
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runner_for() {
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case "$1" in
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linux/arm*) echo "ubuntu-24.04-arm" ;;
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*) echo "ubuntu-latest" ;;
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esac
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}
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# Slug: strip leading "linux/", drop remaining slashes (linux/arm/v7 -> armv7).
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slug_for() {
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local p="${1#linux/}"
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echo "${p//\//}"
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}
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# Print one "os/arch[/variant]" line per real platform in an image's manifest,
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# dropping attestation entries (platform.os == "unknown"). Non-zero if the
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# image ref cannot be inspected (e.g. the tag does not exist).
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platforms_of() {
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docker buildx imagetools inspect --raw "$1" 2>/dev/null \
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| jq -r '.manifests[]?
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| select(.platform.os != null and .platform.os != "unknown")
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| .platform
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| .os + "/" + .architecture
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+ (if (.variant // "") == "" then "" else "/" + .variant end)'
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}
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# Apply containerd's default-variant rule so a base image's "arm64/v8" compares
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# equal to a buildx-pushed image's normalized "arm64". Without this, arm64 would
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# always look missing and every directory would rebuild forever.
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canonical() {
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sed -E 's#^linux/arm64/v8$#linux/arm64#'
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}
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BUILD='[]'
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MERGE='[]'
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while read -r ENTRY; do
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DIRECTORY=$(jq -r '.directory' <<< "${ENTRY}")
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VERSION=$(jq -r '.version' <<< "${ENTRY}")
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# Expected arches come from the directory's pinned Alpine base image.
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BASE_REF=$(grep -iE '^FROM alpine:' "${DIRECTORY}/Dockerfile" | tail -1 | awk '{print $2}')
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EXPECTED=$(platforms_of "${BASE_REF}" | sort -u)
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if [[ -z "${EXPECTED}" ]]; then
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echo "::error::Could not determine architectures for ${DIRECTORY} from ${BASE_REF}"
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exit 1
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fi
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if jq -e --arg d "${DIRECTORY}" 'index($d) != null' <<< "${CHANGED}" > /dev/null; then
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echo "${DIRECTORY}: files changed, building"
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elif ! curl -fsS "https://hub.docker.com/v2/repositories/${REPO_NAME}/tags/${VERSION}" &> /dev/null; then
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echo "${DIRECTORY}: ${REPO_NAME}:${VERSION} not yet published, building"
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else
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echo "${DIRECTORY}: unchanged and already published, skipping"
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continue
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PUBLISHED=$(platforms_of "${REPO_NAME}:${VERSION}" | canonical | sort -u || true)
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if [[ -z "${PUBLISHED}" ]]; then
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echo "${DIRECTORY}: ${REPO_NAME}:${VERSION} not yet published, building"
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else
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MISSING=$(comm -23 <(printf '%s\n' "${EXPECTED}" | canonical) <(printf '%s\n' "${PUBLISHED}"))
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if [[ -n "${MISSING}" ]]; then
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echo "${DIRECTORY}: ${REPO_NAME}:${VERSION} building; architectures missing:"
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printf '%s\n' "${MISSING}" | sed 's/^/ /'
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else
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echo "${DIRECTORY}: unchanged and all arches published, skipping"
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continue
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fi
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fi
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fi
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SELECTED=$(jq -c ". + [${ENTRY}]" <<< "${SELECTED}")
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# Selected: record the directory for merge, and one build entry per arch.
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MERGE=$(jq -c ". + [${ENTRY}]" <<< "${MERGE}")
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while read -r PLATFORM; do
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[[ -z "${PLATFORM}" ]] && continue
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BUILD=$(jq -c \
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--arg directory "${DIRECTORY}" \
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--arg version "${VERSION}" \
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--arg platform "${PLATFORM}" \
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--arg runner "$(runner_for "${PLATFORM}")" \
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--arg slug "$(slug_for "${PLATFORM}")" \
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'. + [{directory: $directory, version: $version, platform: $platform, runner: $runner, slug: $slug}]' \
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<<< "${BUILD}")
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done <<< "${EXPECTED}"
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done < <(jq -c '.[]' <<< "${CANDIDATES}")
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# Each platform builds on the closest runner architecture to minimize QEMU
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# emulation: amd64 natively on amd64, and the arm variants on ARM hosts
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# (arm64v8 natively; armv7/armv6 via aarch32 emulation).
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PLATFORMS='[
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{"name": "linux/amd64", "slug": "amd64", "runner": "ubuntu-latest"},
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{"name": "linux/arm64/v8", "slug": "arm64v8", "runner": "ubuntu-24.04-arm"},
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{"name": "linux/arm/v7", "slug": "armv7", "runner": "ubuntu-24.04-arm"},
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{"name": "linux/arm/v6", "slug": "armv6", "runner": "ubuntu-24.04-arm"}
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]'
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echo "Selected directories: ${SELECTED}"
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echo "merge_matrix={\"include\":${SELECTED}}" >> "${GITHUB_OUTPUT}"
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echo "build_matrix={\"entry\":${SELECTED},\"platform\":$(jq -c . <<< "${PLATFORMS}")}" >> "${GITHUB_OUTPUT}"
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if [[ "${SELECTED}" == "[]" ]]; then
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echo "Selected build matrix: ${BUILD}"
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echo "build_matrix={\"include\":${BUILD}}" >> "${GITHUB_OUTPUT}"
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echo "merge_matrix={\"include\":${MERGE}}" >> "${GITHUB_OUTPUT}"
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if [[ "${BUILD}" == "[]" ]]; then
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echo "has_builds=false" >> "${GITHUB_OUTPUT}"
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else
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echo "has_builds=true" >> "${GITHUB_OUTPUT}"
@@ -135,16 +199,16 @@ jobs:
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- lint
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- setup
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if: needs.setup.outputs.has_builds == 'true'
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runs-on: ${{ matrix.platform.runner }}
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runs-on: ${{ matrix.runner }}
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strategy:
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fail-fast: false
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matrix: ${{ fromJSON(needs.setup.outputs.build_matrix) }}
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env:
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DIRECTORY: ${{ matrix.entry.directory }}
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VERSION: ${{ matrix.entry.version }}
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PLATFORM: ${{ matrix.platform.name }}
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DIRECTORY: ${{ matrix.directory }}
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VERSION: ${{ matrix.version }}
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PLATFORM: ${{ matrix.platform }}
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# Cache scope keeps each directory+platform's layers separate
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CACHE_SCOPE: ${{ matrix.entry.directory }}-${{ matrix.platform.slug }}
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CACHE_SCOPE: ${{ matrix.directory }}-${{ matrix.slug }}
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steps:
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- uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
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@@ -203,13 +267,13 @@ jobs:
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if: github.ref == 'refs/heads/master'
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run: |
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mkdir -p digests
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echo "${{ steps.push.outputs.digest }}" > "digests/${{ matrix.platform.slug }}"
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echo "${{ steps.push.outputs.digest }}" > "digests/${{ matrix.slug }}"
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- name: Upload digest
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if: github.ref == 'refs/heads/master'
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uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
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with:
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name: digests-${{ matrix.entry.directory }}-${{ matrix.platform.slug }}
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name: digests-${{ matrix.directory }}-${{ matrix.slug }}
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path: digests/*
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if-no-files-found: error
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