gha: Release a vendor tarball for distributions to do offline builds

Distributions need to be able to build offline using static sources. I
didn't bother including the tarball in development releases to save
space.

The vendoring is done just before the actual build so that the build can
reuse these files, avoiding the need to download them again for each
platform.

Signed-off-by: James Le Cuirot <[email protected]>

Author: chewi

.github/workflows/release.yml

@@ -52,13 +52,17 @@ jobs:
         fi
         echo "RELEASE_VERSION=${RELEASE_VERSION}"
         RELEASE_NUM="$(date +%Y%m%d%H%M%S).$(git rev-parse --short HEAD)"
+        docker run --rm -v "${PWD}":/src --workdir /src "golang:${{ env.GO_VERSION }}" sh -c "go mod vendor -o /tmp/vendor && tar -C /tmp -c vendor/" | tar -x
         docker buildx build --build-arg RELEASE_NUM=${RELEASE_NUM} --build-arg RELEASE_VERSION=${RELEASE_VERSION} --build-arg GO_VERSION=${{ env.GO_VERSION }} -f .github/workflows/release/Dockerfile --platform=linux/amd64,linux/arm64 -o releases/ .
-        ls -l releases/*/
+        XZ_OPT="-T0 -9" tar --create --auto-compress --file "releases/accelerated-container-image-${GITHUB_REF_NAME#v}-vendor.tar.xz" --transform="s:^:accelerated-container-image-${GITHUB_REF_NAME#v}/:" --owner=root --group=root vendor/
+        ls -l releases/*
     - name: Upload
       uses: actions/upload-artifact@v5
       with:
         name: releases
-        path: releases/*/overlaybd-snapshotter*
+        path: |
+          releases/*/overlaybd-snapshotter*
+          releases/accelerated-container-image-*-vendor.tar.xz
 
   dev-release:
     name: Development Release
@@ -70,7 +74,7 @@ jobs:
         uses: actions/download-artifact@v6
       - name: Display downloaded files
         shell: bash
-        run: ls -l releases/*/
+        run: ls -l releases/*
       - name: Create Release
         uses: "marvinpinto/action-automatic-releases@latest"
         with:
@@ -91,11 +95,12 @@ jobs:
         uses: actions/download-artifact@v6
       - name: Display downloaded files
         shell: bash
-        run: ls -l releases/*/
+        run: ls -l releases/*
       - name: Create Release
         uses: "marvinpinto/action-automatic-releases@latest"
         with:
           repo_token: "${{ secrets.GITHUB_TOKEN }}"
           prerelease: false
           files: |
             releases/*/overlaybd-snapshotter*
+            releases/accelerated-container-image-*-vendor.tar.xz