[CI] Workflow to build and push centos build image (#2174)

.github/workflows/push_centos_build_image.yml

@@ -0,0 +1,40 @@
+name: Build and push centos7 base image
+
+# workflow based on https://docs.github.com/en/actions/publishing-packages/publishing-docker-images#publishing-images-to-github-packages
+on:
+  workflow_dispatch:
+
+jobs:
+  build-and-push-image:
+    env:
+      REGISTRY: ghcr.io
+      IMAGE_NAME: ${{ github.repository }}-centos7-build-image
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3.3.0
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2.1.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v4.3.0
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4.0.0
+        with:
+          file: ./docker/centos.dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

docker/centos.dockerfile

@@ -23,4 +23,6 @@ RUN git clone --depth 1 --branch release/12.x https://github.com/llvm/llvm-proje
     # use gcc_install_prefix to tell clang where gcc containing required libstdc++ is installed
     && scl enable devtoolset-9 -- cmake -DLLVM_ENABLE_PROJECTS=clang -DCMAKE_BUILD_TYPE=Release -DGCC_INSTALL_PREFIX=/opt/rh/devtoolset-9/root/usr/ -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=1 -G "Unix Makefiles" ../llvm \
     && make install \
+    && cd ../../ \
     && rm -rf llvm-project
+