Build and push images on each push to main

Author: ianroberts

.github/workflows/build-docker.yml

@@ -0,0 +1,38 @@
+name: build-docker
+on:
+  push:
+    branches:
+      - 'main'
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Useful variables
+        id: setvars
+        # ghcr.io namespaces must be lower case, but there's no native way
+        # in the GitHub Actions expression language to convert string case,
+        # so we have to do it ourselves in a script.
+        run: echo "repoowner=${{ github.repository_owner }}" | tr 'A-Z' 'a-z' >> "$GITHUB_OUTPUT"
+
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      -
+        name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+
+      -
+        name: Build
+        uses: docker/bake-action@v6
+        env:
+          PROD: "true"
+          DBBR_REGISTRY: ghcr.io/${{ steps.setvars.outputs.repoowner }}/
+        with:
+          files: |
+            ./docker-bake.hcl
+            cwd://${{ steps.meta.outputs.bake-file-labels }}
+          push: true