feat(docker-release): opt-in private-modules BuildKit secret for unvendored Go fetch

.github/workflows/docker-release.yml

@@ -34,6 +34,20 @@ on:
         description: "JSON matrix of services to build (GitHub Actions matrix `include` shape)"
         required: true
         type: string
+      private-modules:
+        description: >-
+          Mint a short-lived, read-only token for the org-wide pinpredict-argocd
+          App (BOOTSTRAP_APP_ID / BOOTSTRAP_APP_PRIVATE_KEY) and expose it to the
+          build as BuildKit secret `id=gh_token`. Opt-in for services whose
+          Dockerfile fetches a private pinpredict module instead of vendoring it
+          (e.g. a Go repo that requires github.com/pinpredict/ppkit) via
+          `RUN --mount=type=secret,id=gh_token ... go mod download`. Handed to
+          buildx as a `--secret`, never a `--build-arg`, so it never lands in an
+          image layer or `docker history`. Default false — a no-op for every
+          existing caller.
+        required: false
+        type: boolean
+        default: false
 
 env:
   AWS_REGION: us-east-1
@@ -115,6 +129,23 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4
 
+      # Opt-in (private-modules: true): mint a short-lived, read-only token for
+      # the org-wide pinpredict-argocd App so the build can fetch private
+      # pinpredict modules without vendoring. contents:read across the org (the
+      # App is installed on all repos); consumed by buildx as a BuildKit
+      # `--secret` below — never a build-arg — so it never lands in an image
+      # layer or `docker history`. Skipped (and the secret omitted) for every
+      # caller that leaves private-modules at its default false.
+      - name: Mint private-module read token
+        id: private-module-token
+        if: ${{ inputs.private-modules }}
+        uses: actions/create-github-app-token@v1
+        with:
+          app-id: ${{ secrets.BOOTSTRAP_APP_ID }}
+          private-key: ${{ secrets.BOOTSTRAP_APP_PRIVATE_KEY }}
+          owner: pinpredict
+          permission-contents: read
+
       - name: Resolve version, build, push, tag
         id: release
         env:
@@ -126,6 +157,9 @@ jobs:
           ECR_REGISTRY: ${{ steps.ecr-login.outputs.registry }}
           SHORT_SHA: ${{ github.sha }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          # Empty unless private-modules minted a token above; gates the
+          # BuildKit --secret so it's a no-op for every other caller.
+          GH_PRIVATE_TOKEN: ${{ steps.private-module-token.outputs.token }}
         run: |
           set -euo pipefail
           SHORT_SHA="${SHORT_SHA:0:7}"
@@ -196,6 +230,15 @@ jobs:
             done <<< "${BUILD_ARGS}"
           fi
 
+          # Private-module fetch (inputs.private-modules): hand the minted App
+          # token to the build as a BuildKit secret, readable inside the
+          # Dockerfile at /run/secrets/gh_token via
+          # `RUN --mount=type=secret,id=gh_token`. Only added when the token
+          # step ran (env non-empty) — a no-op for every other caller.
+          if [ -n "${GH_PRIVATE_TOKEN:-}" ]; then
+            buildx_args+=(--secret "id=gh_token,env=GH_PRIVATE_TOKEN")
+          fi
+
           docker buildx build "${buildx_args[@]}" .
 
           # Tag immediately after successful push (retry up to 3 times).

README.md

@@ -10,7 +10,7 @@ Why `.github` and not a dedicated `github-actions` repo: `.github` is *the* GitH
 
 | File | Purpose |
 |---|---|
-| `docker-release.yml` | Matrix-based image build + push to ECR. Version = highest `X.Y.Z` tag in the ECR repo + 1 (ECR is the version record — platform-gitops#1201); advances the `refs/releases/image/<name>` marker ref, mints the legacy `image/<name>/X.Y.Z` git tag (Dispatch correlation, being phased out), aggregated GitHub Release. Caller passes a `matrix` input in the standard `{include:[...]}` shape. |
+| `docker-release.yml` | Matrix-based image build + push to ECR. Version = highest `X.Y.Z` tag in the ECR repo + 1 (ECR is the version record — platform-gitops#1201); advances the `refs/releases/image/<name>` marker ref, mints the legacy `image/<name>/X.Y.Z` git tag (Dispatch correlation, being phased out), aggregated GitHub Release. Caller passes a `matrix` input in the standard `{include:[...]}` shape. Optional `private-modules: true` mints a short-lived read-only `pinpredict-argocd` App token and exposes it to the build as BuildKit secret `id=gh_token` (`RUN --mount=type=secret,id=gh_token …`) — for Dockerfiles that fetch a private pinpredict module (e.g. `github.com/pinpredict/ppkit`) instead of vendoring it. Default false. |
 | `chart-release.yml` | Auto-discovers `charts/*/`, skips charts unchanged since their `refs/releases/chart/<name>` marker ref, resolves the next version from the ECR OCI repo, packages, pushes, advances the marker, mints the legacy `chart/<name>/X.Y.Z` tag. No caller inputs. |
 | `tag-config.yml` | Tags merges to main that touch `.platform/services/<svc>.yaml` with `vX.Y.Z+<svc>` (per-service Kargo `<svc>-config` Warehouse freight), then dispatches `service-config-tag` to platform-gitops so missing pointer files get seeded. |
 | `actionlint.yml` | Lints GitHub Actions workflow YAML with [`actionlint`](https://github.com/rhysd/actionlint) at a pinned version. Self-runs on this repo when PRs/pushes touch `.github/workflows/**` or `actions/**/action.yml`; callers reuse it via `uses: pinpredict/.github/.github/workflows/actionlint.yml@main`. |