feat: add use-buildx option to fall back to plain docker build

.gitea/actions/docker-build/action.yml

@@ -39,6 +39,9 @@ inputs:
   build-args:
     description: Build args as CSV KEY=VALUE
     default: ""
+  use-buildx:
+    description: Use docker buildx (set to false for runners without buildx support)
+    default: "true"
 
 outputs:
   image:
@@ -61,13 +64,14 @@ runs:
   steps:
     - name: Set up QEMU for multi-platform builds
       shell: bash
-      if: inputs.platforms != 'linux/amd64'
+      if: inputs.use-buildx == 'true' && inputs.platforms != 'linux/amd64'
       run: |
         docker run --rm --privileged multiarch/qemu-user-static --reset -p yes 2>/dev/null || true
 
     - name: Set up Docker Buildx
       id: buildx
       shell: bash
+      if: inputs.use-buildx == 'true'
       run: |
         mkdir -p $HOME/.docker/cli-plugins
         curl -fsSL https://github.com/docker/buildx/releases/download/v0.12.1/buildx-v0.12.1.linux-amd64 \
@@ -141,7 +145,7 @@ runs:
         DOCKER_BUILDKIT: "1"
       run: |
         CACHE_FROM_FLAG=""
-        if [ -n "${{ inputs.cache-from }}" ]; then
+        if [ -n "${{ inputs.cache-from }}" ] && [ "${{ inputs.use-buildx }}" = "true" ]; then
           CACHE_FROM_FLAG="--cache-from=${{ inputs.cache-from }}"
         fi
 
@@ -153,30 +157,57 @@ runs:
         fi
 
         PLATFORM_FLAG=""
-        if [ "${{ inputs.platforms }}" != "linux/amd64" ]; then
+        if [ "${{ inputs.use-buildx }}" = "true" ] && [ "${{ inputs.platforms }}" != "linux/amd64" ]; then
           PLATFORM_FLAG="--platform=${{ inputs.platforms }}"
         fi
 
-        # Choose output mode
-        if [ "${{ inputs.push }}" = "true" ]; then
-          OUTPUT_FLAG="--push --output=type=registry"
-        else
-          OUTPUT_FLAG="--load --output=type=docker"
-        fi
+        if [ "${{ inputs.use-buildx }}" = "true" ]; then
+          # Use docker buildx
+          if [ "${{ inputs.push }}" = "true" ]; then
+            OUTPUT_FLAG="--push --output=type=registry"
+          else
+            OUTPUT_FLAG="--load --output=type=docker"
+          fi
 
-        set -x
-        docker buildx build \
-          $PLATFORM_FLAG \
-          --tag "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}" \
-          --tag "${{ inputs.image-name }}:latest" \
-          $(for t in $(echo ${{ steps.meta.outputs.tags }} | tr ',' ' '); do echo -n "--tag ${{ inputs.image-name }}:$t "; done) \
-          --file ${{ inputs.context }}/${{ inputs.dockerfile }} \
-          --cache-to=${{ inputs.cache-to }} \
-          $CACHE_FROM_FLAG \
-          $BUILD_ARGS_FLAG \
-          --progress=plain \
-          $OUTPUT_FLAG \
-          ${{ inputs.context }}
+          set -x
+          docker buildx build \
+            $PLATFORM_FLAG \
+            --tag "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}" \
+            --tag "${{ inputs.image-name }}:latest" \
+            $(for t in $(echo ${{ steps.meta.outputs.tags }} | tr ',' ' '); do echo -n "--tag ${{ inputs.image-name }}:$t "; done) \
+            --file ${{ inputs.context }}/${{ inputs.dockerfile }} \
+            --cache-to=${{ inputs.cache-to }} \
+            $CACHE_FROM_FLAG \
+            $BUILD_ARGS_FLAG \
+            --progress=plain \
+            $OUTPUT_FLAG \
+            ${{ inputs.context }}
+        else
+          # Plain docker build (no buildx)
+          if [ "${{ inputs.push }}" = "true" ]; then
+            set -x
+            docker build \
+              --tag "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}" \
+              --tag "${{ inputs.image-name }}:latest" \
+              $(for t in $(echo ${{ steps.meta.outputs.tags }} | tr ',' ' '); do echo -n "--tag ${{ inputs.image-name }}:$t "; done) \
+              --file ${{ inputs.context }}/${{ inputs.dockerfile }} \
+              $BUILD_ARGS_FLAG \
+              --progress=plain \
+              ${{ inputs.context }}
+            docker push "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}"
+            docker push "${{ inputs.image-name }}:latest"
+          else
+            set -x
+            docker build \
+              --tag "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}" \
+              --tag "${{ inputs.image-name }}:latest" \
+              $(for t in $(echo ${{ steps.meta.outputs.tags }} | tr ',' ' '); do echo -n "--tag ${{ inputs.image-name }}:$t "; done) \
+              --file ${{ inputs.context }}/${{ inputs.dockerfile }} \
+              $BUILD_ARGS_FLAG \
+              --progress=plain \
+              ${{ inputs.context }}
+          fi
+        fi
 
     - name: Get image digest
       id: push-digest