使用 GitHub Actions 添加镜像注释

注释允许您为OCI镜像组件指定任意元数据，例如清单、索引和描述符。

在使用 GitHub Actions 构建镜像时添加注解，请使用 metadata-action 自动创建符合 OCI 规范的注解。metadata action 会生成一个 annotations 输出，您可以在 build-push-action 和 bake-action 中引用。

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

配置注解级别

默认情况下，注解放置在镜像清单上。要配置注解级别，请在 metadata-action 步骤中设置 DOCKER_METADATA_ANNOTATIONS_LEVELS 环境变量为逗号分隔的列表，列出您希望进行注解的所有级别。例如，将 DOCKER_METADATA_ANNOTATIONS_LEVELS 设置为 index 将导致在镜像索引上进行注解，而不是在清单上。

以下示例在镜像索引和清单上创建注释。

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
构建必须生成您要注释的组件。例如，要注释镜像索引，构建必须生成一个索引。如果构建仅生成清单，而您指定 index 或 index-descriptor，则构建将失败。