add github work flow to build container and publish gem

.dockerignore

@@ -1,3 +1,4 @@
 /.git
+/.github
 /deployment
 .*.swp

.github/workflows/build-and-publish.yaml

@@ -0,0 +1,64 @@
+name: Build the ruby gem in a container and publish it on Github Package Repository
+on:
+  pull_request:
+  release:
+    types:
+      - publish
+
+jobs:
+  build-ruby-gem:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout project code
+        uses: actions/checkout@v4
+
+      - name: Setup Docker builder
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build container for build target
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./deployment/Containerfile
+          target: build
+          push: false
+          tags: linuxfrorg/board-sse-linuxfr.org:${{ github.sha }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      - name: Publish gem to Github Package Repository
+        uses: addnab/docker-run-action@v3
+        env:
+          GITHUB_EVENT_NAME: ${{ github.event_name }}
+          GEM_HOST_API_KEY: "Bearer ${{secrets.GITHUB_TOKEN}}"
+          OWNER: ${{ github.repository_owner }}
+        with:
+          image: linuxfrorg/board-sse-linuxfr.org:${{ github.sha }}
+          options: >-
+            -e OWNER
+            -e GEM_HOST_API_KEY
+            -e GITHUB_EVENT_NAME
+          run: |
+            set -eux
+            IFS=$'\n\t'
+
+            if [ "${GITHUB_EVENT_NAME}" = 'release' ]
+            then
+              echo "Start publish a new release"
+            else
+              echo "Skip publish step, because we are not publishing a release"
+              exit 0
+            fi
+
+            mkdir -p "${HOME}/.gem"
+            touch "${HOME}/.gem/credentials"
+            chmod 0600 "${HOME}/.gem/credentials"
+            printf -- "---\n:github: ${GEM_HOST_API_KEY}\n" > "${HOME}/.gem/credentials"
+            gem push --KEY github --host "https://rubygems.pkg.github.com/${OWNER}" *.gem

deployment/Containerfile

@@ -1,4 +1,4 @@
-FROM ruby:3-slim-bookworm
+FROM ruby:3-slim-bookworm AS build
 
 LABEL org.opencontainers.image.title="LinuxFr.org boards"
 LABEL org.opencontainers.image.description="Chat rooms for LinuxFr"
@@ -10,20 +10,29 @@ LABEL org.opencontainers.image.authors="Adrien Dorsaz <adrien@adorsaz.ch>"
 
 ARG UID=1200
 
-RUN apt-get update \
-  # Install dependencies \
-  && apt-get install -y --no-install-recommends \
-    build-essential ruby ruby-dev \
-  && apt-get clean
+RUN <<EOF
+set -eux
+IFS=$'\n\t'
+
+apt-get update
+
+apt-get install -y --no-install-recommends \
+  build-essential ruby ruby-dev
+
+apt-get clean
+EOF
 
 USER ${UID}
 WORKDIR /linuxfr-board
 ENV HOME=/linuxfr-board
 
 # Install board-linuxfr
 COPY --chown=${UID}:0 --chmod=770 . .
-RUN gem build board-linuxfr.gemspec \
-  && gem install ./board-linuxfr-*.gem
+RUN gem build board-linuxfr.gemspec
+
+FROM build as productioproduction
+
+RUN gem install ./board-linuxfr-*.gem
 
 # Clean development dependencies
 USER 0