Add a 'Docker Code Quality' GitHub workflow.

Initially just checks that the 'Dockerfile' files are valid.

2 files changed, 43 insertions, 0 deletions

diff --git a/.github/workflows/docker-code-quality.yml b/.github/workflows/docker-code-quality.yml
new file mode 100644
index 000000000..e96baf281
--- /dev/null
+++ b/.github/workflows/docker-code-quality.yml
@@ -0,0 +1,39 @@
+name: Docker Code Quality
+
+on:
+  pull_request:
+    paths:
+    - '.docker/**'
+  # Allow manual triggering
+  workflow_dispatch:
+  # Allow other workflows (e.g. Publish) to invoke this one.
+  workflow_call:
+
+
+permissions:
+  contents: read
+
+
+jobs:
+  check:
+    name: Check Docker image ${{ matrix.image.name }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        image:
+        - name: app
+          dockerfile: ./.docker/app/Dockerfile
+        - name: web-nginx
+          dockerfile: ./.docker/web-nginx/Dockerfile
+
+    steps:
+    - name: Check out code
+      uses: actions/checkout@v5
+
+    - name: Validate configuration
+      uses: docker/build-push-action@v6
+      with:
+        context: .
+        file: ${{ matrix.image.dockerfile }}
+        call: check
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 1ef46b631..1a5e19e22 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -24,12 +24,16 @@ permissions:
 
 
 jobs:
+  test-docker:
+    uses: ./.github/workflows/docker-code-quality.yml
+
   test-php:
     uses: ./.github/workflows/php-code-quality.yml
 
   publish:
     name: Publish Docker image ${{ matrix.image.name }}
     needs:
+    - test-docker
     - test-php
     runs-on: ubuntu-latest
     permissions: