Resolve some issues with the combine manifests job

Author: dsobek

.github/workflows/earthly-build.yaml

@@ -66,14 +66,7 @@ jobs:
           sudo wget https://github.com/earthly/earthly/releases/latest/download/earthly-linux-${{ matrix.arch }} -O /usr/local/bin/earthly
           sudo chmod 755 /usr/local/bin/earthly
 
-      - name: Login to Docker Hub
-        uses: docker/login-action@v3
-        with:
-          username: ${{ env.DOCKER_HUB_USERNAME }}
-          password: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
-
-      - name: Build spaceros image and push it to Dockerhub
-        id: push_image
+      - name: Build spaceros image without pushing
         run: |
           earthly --ci --output +push-main-image \
             --VCS_REF="$VCS_REF" \
@@ -96,20 +89,26 @@ jobs:
           docker tag "$DOCKER_HUB_IMAGE_NAME:$ARCH_IMAGE_TAG" "$GHCR_IMAGE_NAME:$ARCH_IMAGE_TAG"
           docker push "$GHCR_IMAGE_NAME:$ARCH_IMAGE_TAG"
 
+      # Push both tagged releases and the latest main builds to Dockerhub
+      - name: Push spaceros images to Dockerhub
+        if: ${{ github.ref_type == 'tag' || github.ref_name == 'main' }}
+        id: push_image
+        env: 
+          DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
+        run: |
+          # We must login using the password and not the action, as the action only supports tokens.
+          echo "$DOCKER_HUB_TOKEN" | docker login --username "$DOCKER_HUB_USERNAME" --password-stdin
+          docker push "$DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG"
+          echo "output_${{ matrix.arch }}=$DOCKER_HUB_IMAGE_NAME:$ARCH_IMAGE_TAG" >> "$GITHUB_OUTPUT"
+
 
   combine-main-image-manifests:
+    needs: space-ros-main-image
+    # If we've pushed a main image
+    if: ${{ join(needs.space-ros-main-image.outputs, '') != '' }}
     env:
       IMAGE_TAG: "${{ github.head_ref || github.ref_name }}"
-      
-    runs-on: ubuntu-latest
-    needs: space-ros-main-image
     steps:
-      - name: Login to Docker Hub
-        uses: docker/login-action@v3
-        with:
-          username: ${{ env.DOCKER_HUB_USERNAME }}
-          password: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
-
       - name: Combine Manifests
         run: |
           docker manifest create osrf/space-ros:${{ github.ref_name }} \
@@ -119,11 +118,15 @@ jobs:
       # Any tagged image should also be marked as "latest"
       - name: Push spaceros latest images to Dockerhub
         if: ${{ github.ref_type == 'tag' }}
+        env: 
+          DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
         run: |
           # We must login using the password and not the action, as the action only supports tokens.
+          echo "$DOCKER_HUB_TOKEN" | docker login --username "$DOCKER_HUB_USERNAME" --password-stdin
           docker tag "$DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG" "$DOCKER_HUB_IMAGE_NAME:latest"
           docker push "$DOCKER_HUB_IMAGE_NAME:latest"
 
+
   space-ros-dev-image:
     runs-on: ubuntu-latest
     env: