Docker: don't login without creds

.github/scripts/docker-build.bash

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -ex
 
-DOCKERHUB_IMAGE_ID=$DOCKERHUB_ACCOUNT/$IMAGE_NAME
+DOCKERHUB_IMAGE_ID=$DOCKERHUB_USERNAME/$IMAGE_NAME
 
 # Change all uppercase to lowercase
 DOCKERHUB_IMAGE_ID=$(echo $DOCKERHUB_IMAGE_ID | tr '[A-Z]' '[a-z]')
@@ -39,7 +39,7 @@ fi
 docker buildx build \
     ${push_image} \
     ${image_platforms} \
-    --cache-from=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:$cache_tag \
-    --cache-to=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:$cache_tag,mode=max \
+    --cache-from=type=registry,ref=$DOCKERHUB_USERNAME/$IMAGE_NAME:$cache_tag \
+    --cache-to=type=registry,ref=$DOCKERHUB_USERNAME/$IMAGE_NAME:$cache_tag,mode=max \
     "${image_tags[@]}" \
     .

.github/workflows/docker.yaml

@@ -23,13 +23,12 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-env:
-  IMAGE_NAME: conky
-  DOCKERHUB_ACCOUNT: brndnmtthws
-  DOCKER_BUILDKIT: 1
-
 jobs:
   docker-buildx:
+    env:
+      IMAGE_NAME: conky
+      DOCKER_BUILDKIT: 1
+      DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -41,6 +40,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
       - name: Login to Docker Hub
         uses: docker/login-action@v3
+        if: ${{ env.DOCKERHUB_USERNAME != '' }}
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}