使用 GitHub Actions 的命名上下文

您可以定义其他构建上下文, 并在 Dockerfile 中使用 或 .什么时候 Dockerfile 定义一个与被覆盖的同名阶段。FROM name--from=name

这对于 GitHub Actions 重用其他构建或 pin 的结果非常有用 镜像添加到工作流程中的特定标签。

将镜像固定到标签

替换为固定的:alpine:latest

# syntax=docker/dockerfile:1
FROM alpine
RUN echo "Hello World"
name: ci

on:
  push:

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Build
        uses: docker/build-push-action@v6
        with:
          build-contexts: |
            alpine=docker-image://alpine:3.21            
          tags: myimage:latest

在后续步骤中使用镜像

默认情况下,Docker Setup Buildx 操作用作构建驱动程序,因此构建的 Docker 镜像不是 自动加载。docker-container

使用命名上下文,您可以重用构建的镜像:

# syntax=docker/dockerfile:1
FROM alpine
RUN echo "Hello World"
name: ci

on:
  push:

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          driver: docker

      - name: Build base image
        uses: docker/build-push-action@v6
        with:
          context: "{{defaultContext}}:base"
          load: true
          tags: my-base-image:latest

      - name: Build
        uses: docker/build-push-action@v6
        with:
          build-contexts: |
            alpine=docker-image://my-base-image:latest            
          tags: myimage:latest

与容器生成器一起使用

如上一节所示,我们没有使用默认的 docker-container 驱动程序进行构建 命名上下文。这是因为此驱动程序无法从 Docker 加载镜像 store 的 SET 文件。要解决此问题,您可以使用本地注册表在工作流程中推送基础镜像:

# syntax=docker/dockerfile:1
FROM alpine
RUN echo "Hello World"
name: ci

on:
  push:

jobs:
  docker:
    runs-on: ubuntu-latest
    services:
      registry:
        image: registry:2
        ports:
          - 5000:5000
    steps:
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          # network=host driver-opt needed to push to local registry
          driver-opts: network=host

      - name: Build base image
        uses: docker/build-push-action@v6
        with:
          context: "{{defaultContext}}:base"
          tags: localhost:5000/my-base-image:latest
          push: true

      - name: Build
        uses: docker/build-push-action@v6
        with:
          build-contexts: |
            alpine=docker-image://localhost:5000/my-base-image:latest            
          tags: myimage:latest