Add docker-build composite action

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

@@ -0,0 +1,154 @@
+name: Docker Build + Push
+description: Build and push Docker images with buildx and layer caching for Gitea Actions
+author: eric
+
+inputs:
+  dockerfile:
+    description: Path to Dockerfile (relative to build_context)
+    default: Dockerfile
+  context:
+    description: Build context path (relative to repo root)
+    default: .
+  image-name:
+    description: Full image name (e.g. registry/image or image)
+    required: true
+  tags:
+    description: Additional tags as CSV appended to defaults
+    default: ""
+  cache-from:
+    description: Cache source (e.g. type=gha, or image:tag)
+    default: ""
+  cache-to:
+    description: Cache destination for buildx (type=gha or type=local)
+    default: type=local,dest=/tmp/buildx-cache,mode=max
+  platforms:
+    description: Target platforms as CSV (e.g. linux/amd64,linux/arm64)
+    default: linux/amd64
+  push:
+    description: Push images to registry after build
+    default: "false"
+  build-args:
+    description: Build args as CSV KEY=VALUE
+    default: ""
+
+outputs:
+  image:
+    description: Full image name with tag
+    value: ${{ steps.meta.outputs.image }}
+  tag:
+    description: The primary tag used (date-SHA)
+    value: ${{ steps.meta.outputs.tag }}
+  digest:
+    description: Image digest (only available after push)
+    value: ${{ steps.push-digest.outputs.digest }}
+
+runs:
+  using: composite
+  env:
+    DOCKER_HOST: tcp://docker.local:2375
+    DOCKER_BUILDKIT: "1"
+    BUILDKIT_HOST: tcp://docker.local:2375
+
+  steps:
+    - name: Set up QEMU for multi-platform builds
+      shell: bash
+      if: 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
+      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 \
+          -o $HOME/.docker/cli-plugins/docker-buildx
+        chmod +x $HOME/.docker/cli-plugins/docker-buildx
+        docker buildx version
+
+        # Create a builder instance (reuse if exists)
+        docker buildx create \
+          --name gitea-builder \
+          --driver docker-container \
+          --driver-opt image=moby/buildkit:buildx-stable-1 \
+          --driver-opt network=host \
+          --use \
+          2>/dev/null || docker buildx use gitea-builder
+
+        docker buildx inspect --bootstrap
+
+    - name: Compute metadata
+      id: meta
+      shell: bash
+      run: |
+        # Generate tags
+        TAGS="latest"
+        if [ -n "${{ inputs.tags }}" ]; then
+          TAGS="$TAGS,${{ inputs.tags }}"
+        fi
+
+        SHORT_SHA="$(git rev-parse --short HEAD 2>/dev/null || echo 'local')"
+        DATE_TAG="$(date +%Y-%m-%d)"
+        TAG="$DATE_TAG-$SHORT_SHA"
+        TAGS="$TAGS,$TAG"
+
+        # Add git tag if this is a tag push
+        if [ "${{ github.ref_type }}" = "tag" ] || [[ "${{ github.ref }}" == refs/tags/* ]]; then
+          TAG_NAME="${1#refs/tags/}"
+          TAGS="$TAGS,$TAG_NAME"
+        fi
+
+        echo "image=${{ inputs.image-name }}" >> $GITHUB_OUTPUT
+        echo "tag=$TAG" >> $GITHUB_OUTPUT
+        echo "tags=$TAGS" >> $GITHUB_OUTPUT
+
+    - name: Build image
+      id: build
+      shell: bash
+      env:
+        DOCKER_BUILDKIT: "1"
+      run: |
+        set -x
+        CACHE_FROM_FLAG=""
+        if [ -n "${{ inputs.cache-from }}" ]; then
+          CACHE_FROM_FLAG="--cache-from=${{ inputs.cache-from }}"
+        fi
+
+        BUILD_ARGS_FLAG=""
+        if [ -n "${{ inputs.build-args }}" ]; then
+          for arg in $(echo "${{ inputs.build-args }}" | tr ',' ' '); do
+            BUILD_ARGS_FLAG="$BUILD_ARGS_FLAG --build-arg=$arg"
+          done
+        fi
+
+        PLATFORM_FLAG=""
+        if [ "${{ inputs.platforms }}" != "linux/amd64" ]; then
+          PLATFORM_FLAG="--platform=${{ inputs.platforms }}"
+        fi
+
+        PUSH_FLAG=""
+        if [ "${{ inputs.push }}" = "true" ]; then
+          PUSH_FLAG="--push"
+        fi
+
+        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 \
+          $PUSH_FLAG \
+          ${{ inputs.context }}
+
+    - name: Get image digest
+      id: push-digest
+      shell: bash
+      if: inputs.push == 'true'
+      run: |
+        DIGEST="$(docker inspect "${{ inputs.image-name }}:${{ steps.meta.outputs.tag }}" --format '{{.Digest}}' 2>/dev/null)"
+        echo "digest=$DIGEST" >> $GITHUB_OUTPUT
+        echo "digest_full=${{ inputs.image-name }}@$DIGEST" >> $GITHUB_OUTPUT