name: universal-rebuild

# Weekly rebuild of the universal image on top of the current :latest
# vanilla image, so apt security updates flow into universal even when
# kandev itself hasn't been re-released.
#
# - Pushes a moving `:universal-weekly-YYYYMMDD` tag plus refreshes
#   `:universal` (the "latest universal" alias).
# - Does NOT push `:vX.Y.Z-universal`. Those are immutable per release;
#   only the floating `:universal` and the dated weekly tags move here.
#
# Build flow mirrors release.yml's docker-universal: push to a per-run
# staging tag, gate on size against the staging tag, then promote the
# manifest to the user-facing tags via `buildx imagetools create`. The
# promote step is metadata-only - no rebuild, no extra layer upload - so
# a failed size gate aborts before `:universal` ever points at an
# oversized image (the previous week's tag remains live).
#
# Tradeoff: staging tags (one per weekly run) accumulate in GHCR. See the
# comment in release.yml's docker-universal job for why per-run cleanup
# isn't safe (shared manifest digest with promoted tags). A separate
# cleanup workflow filtering for `universal-staging-*` versions whose
# only tag matches is the right escape hatch if accumulation becomes a
# problem; ~52 stale tags/year is acceptable in the meantime.
#
# Manual trigger is also wired up so a maintainer can force a rebuild
# after a known CVE without waiting for the cron.

on:
  schedule:
    # Mondays 06:00 UTC. Picks up the previous week's Debian security
    # patches without colliding with most weekday release work.
    - cron: "0 6 * * 1"
  workflow_dispatch: {}

permissions:
  contents: read

jobs:
  rebuild:
    name: Rebuild universal on top of :latest
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    env:
      STAGING_IMAGE: ghcr.io/kdlbs/kandev:universal-staging-weekly-${{ github.run_id }}
    steps:
      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6

      - name: Compute date tag
        id: date
        run: echo "tag=$(date -u +%Y%m%d)" >> "$GITHUB_OUTPUT"

      - uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4.2.0

      - name: Login to GHCR
        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Rebuild against :latest deliberately - the whole point of the
      # weekly is to pick up any base-image moves. Use --pull so the
      # current :latest is freshly fetched, not whatever's in BuildKit's
      # cache from a previous run.
      - name: Build and push (staging tag)
        uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a # v7.3.0
        with:
          context: .
          file: Dockerfile.universal
          push: true
          pull: true
          platforms: linux/amd64,linux/arm64
          # BASE_IMAGE is intentionally unpinned: the whole point of this
          # weekly job is to pick up the current :latest on each run.
          build-args: |
            BASE_IMAGE=ghcr.io/kdlbs/kandev:latest
          tags: ${{ env.STAGING_IMAGE }}
          cache-from: type=gha,scope=universal
          cache-to: type=gha,mode=max,scope=universal

      # Same size gate as release.yml's docker-universal job. A base-image
      # update that adds significant weight (e.g. a new Debian dep pulled by
      # apt security updates) is caught here before :universal is promoted.
      # Keep MAX in sync with release.yml.
      - name: Enforce size budget
        env:
          MAX_COMPRESSED_BYTES: "2684354560"   # 2.5 GiB
        run: |
          set -euo pipefail
          docker buildx imagetools inspect "$STAGING_IMAGE" --raw \
              > /tmp/index.json
          AMD64_DIGEST="$(jq -r '
              .manifests[]
              | select(.platform.architecture == "amd64" and .platform.os == "linux")
              | .digest
            ' /tmp/index.json)"
          docker buildx imagetools inspect "ghcr.io/kdlbs/kandev@${AMD64_DIGEST}" --raw \
              > /tmp/manifest.json
          TOTAL="$(jq '[.layers[].size] | add' /tmp/manifest.json)"
          echo "Universal image (amd64) compressed size: $TOTAL bytes (max: $MAX_COMPRESSED_BYTES)"
          if [ "$TOTAL" -gt "$MAX_COMPRESSED_BYTES" ]; then
            echo "::error::Universal weekly rebuild exceeds compressed-size budget. Staging tag $STAGING_IMAGE will not be promoted; previous :universal remains live. See docs/images.md inclusion policy." >&2
            exit 1
          fi

      # Promote: metadata-only retag from staging to the user-facing tags.
      # If any earlier step fails, the previous :universal stays in place.
      - name: Promote staging to final tags
        run: |
          set -euo pipefail
          docker buildx imagetools create \
            --tag "ghcr.io/kdlbs/kandev:universal" \
            --tag "ghcr.io/kdlbs/kandev:universal-weekly-${{ steps.date.outputs.tag }}" \
            "$STAGING_IMAGE"