Add docker build/publish CI

.github/workflows/build-and-publish-docker.yml

@@ -0,0 +1,61 @@
+name: Publish Docker images
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to Docker Hub and GHCR
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+      contents: read
+      attestations: write
+      id-token: write
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v4
+
+      - name: Extract version from setup.py
+        # Note: explicitly requesting bash will mean bash is invoked with `-eo pipefail`, see
+        # https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsshell
+        shell: bash
+        run: |
+          echo "RELEASE_VERSION=$(grep "^version" setup.py | sed -E 's/\s*version\s*=\s*["]([^"]*)["],/\1/')" >> $GITHUB_ENV     
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PERSONAL_ACCESS_TOKEN }}
+
+      - name: Log in to GitHub Container registry
+        uses: docker/login-action@65b78e6e13532edd9afa3aa52ac7964289d1a9c1
+        with:
+          registry: ghcr.io
+          # Login as the user that published the release.
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
+        with:
+          images: |
+            docker.io/matrixdotorg/mscbot-python
+            ghcr.io/matrix-org/mscbot-python
+
+      - name: Build and push images
+        id: push
+        uses: docker/build-push-action@3b5e8027fcad23fda98b2e3ac259d8d67585f671
+        with:
+          context: .
+          file: ./Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: |
+            gitsha1=${{ github.sha }}
+            org.opencontainers.image.version=${{ env.RELEASE_VERSION }}
+            ${{ steps.meta.outputs.labels }}