使用 GitHub Actions 添加镜像注释

通过注释，您可以为 OCI 镜像组件指定任意元数据，例如作为清单、索引和描述符。

要在使用 GitHub Actions 构建镜像时添加注释，请使用 metadata-action 自动创建符合 OCI 的注释。这 metadata作会创建一个annotationsoutput 中可以引用的使用 build-push-action 和 bake-action。

name: ci

on:
  push:

env:
  IMAGE_NAME: user/app

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE_NAME }}

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          tags: ${{ steps.meta.outputs.tags }}
          annotations: ${{ steps.meta.outputs.annotations }}
          push: true

name: ci

on:
  push:

env:
  IMAGE_NAME: user/app

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE_NAME }}

      - name: Build
        uses: docker/bake-action@v5
        with:
          files: |
            ./docker-bake.hcl
            ${{ steps.meta.outputs.bake-file-tags }}
            ${{ steps.meta.outputs.bake-file-annotations }}            
          push: true

配置注释级别

默认情况下，注释放置在镜像清单上。要配置注释级别，请将这DOCKER_METADATA_ANNOTATIONS_LEVELS环境变量metadata-action步骤到您想要注释。例如，将DOCKER_METADATA_ANNOTATIONS_LEVELS自index导致 image 索引而不是清单上出现 annotations。

以下示例在 image 索引和体现。

name: ci

on:
  push:

env:
  IMAGE_NAME: user/app

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE_NAME }}
        env:
          DOCKER_METADATA_ANNOTATIONS_LEVELS: manifest,index

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          tags: ${{ steps.meta.outputs.tags }}
          annotations: ${{ steps.meta.outputs.annotations }}
          push: true

注意
生成必须生成要注释的组件。例如要注释镜像索引，构建必须生成索引。如果构建仅生成一个清单，并且您指定index或index-descriptor这 build 失败。