build docker image for each branch/PR?

.github/workflows/docker.yml

@@ -2,24 +2,20 @@ name: Build and push Docker image (amd64, arm64 to hub.docker.com and ghcr.io)
 
 on:
   workflow_dispatch: # allow manual trigger
-  # https://github.com/orgs/community/discussions/26276
-  push:
-    branches:
-      - "main"
-      - "v*"
-    tags:
-       - "v*"
-    paths: # ignore changes to certain files
+  push: # build for each branch
+    # branches: ["main"]
+    paths: # ignore changes to .md files
       - '**'
       - '!*.md'
       # - '!.github/**'
-  pull_request: # runs when opened/reopned or when the head branch is updated, see https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request
-    branches:
-      - "main" # only PRs against main
+  pull_request: # runs when opened/reopned or when the head branch is updated
 
 permissions:
   contents: read
 
+env:
+ BRANCH: ${{ github.head_ref || github.ref_name }} # head_ref/base_ref are only set for PRs, for branches ref_name will be used
+
 jobs:
   docker:
     runs-on: ubuntu-latest
@@ -30,13 +26,11 @@ jobs:
       -
         name: Set environment variables
         run: |
-          BRANCH="${GITHUB_REF#refs/heads/}"
-          echo "BRANCH=$BRANCH" >> "$GITHUB_ENV"
-          echo "NOW=$(date -R)" >> "$GITHUB_ENV" # date -Iseconds; date +'%Y-%m-%dT%H:%M:%S'
+          echo "NOW=$(date -R)" >> $GITHUB_ENV # date -Iseconds; date +'%Y-%m-%dT%H:%M:%S'
           if [[ "$BRANCH" == "main" ]]; then
-            echo "IMAGE_TAG=latest" >> "$GITHUB_ENV"
+            echo "IMAGE_TAG=latest" >> $GITHUB_ENV
           else
-            echo "IMAGE_TAG=$BRANCH" >> "$GITHUB_ENV"
+            echo "IMAGE_TAG=$BRANCH" >> $GITHUB_ENV
           fi
       -
         name: Set up QEMU
@@ -47,7 +41,7 @@ jobs:
       -
         name: Login to Docker Hub
         uses: docker/login-action@v3
-        if: github.event_name != 'pull_request' # TODO if DOCKERHUB_* are set?
+        if: ${{ secrets.DOCKERHUB_USERNAME != '' && secrets.DOCKERHUB_TOKEN != '' }}
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
@@ -61,16 +55,15 @@ jobs:
       -
         name: Build and push
         uses: docker/build-push-action@v6
-        # if: github.event_name != 'pull_request' # still want to build image
+        if: ${{ env.IMAGE_TAG != '' }}
         with:
           context: .
-          push: ${{ github.event_name != 'pull_request' }} # TODO push for forks?
+          push: ${{ secrets.DOCKERHUB_USERNAME != '' }}
           build-args: |
             COMMIT=${{ github.sha }}
             BRANCH=${{ env.BRANCH }}
             NOW=${{ env.NOW }}
-          platforms: linux/amd64,linux/arm64 # ,linux/arm/v7
-          # TODO docker tag only if DOCKERHUB_* are set?
+          platforms: linux/amd64,linux/arm64
           tags: |
             ${{ secrets.DOCKERHUB_USERNAME }}/free-games-claimer:${{env.IMAGE_TAG}}
             ghcr.io/${{ github.actor }}/free-games-claimer:${{env.IMAGE_TAG}}