巧用Github Action 自动推送docker镜像，白piao github服务器资源，还省时又省力

对于个人开发者来说如果不想再自己电脑上搭建CI/DI系统（毕竟吃资源），Github Action是一个不二的选择。

本文我们来通过 Github Action 实现 SpringBoot 项目的自动编译、制作doceker镜像，最后推送到docker hub 仓库。

Github Action 是 Github 推出的一个持续集成和持续交付的平台，能够让你自动化你的编译、测试和部署流程。基础教程：Github Action 指南

1. 说说workflow 流程

先来说说springboot项目打包成docker镜像，并上传到仓库的流程

• 1. 使用springboot项目 https://github.com/admin4j/alertmanager-dingtalk-webhook
• 2. 运行maven命令 mvn -B clean package --file pom.xml 打包jar文件
• 3. 运行docker build构建docker镜像
• 4. 使用docker push 推送docker镜像

2. 配置 docker hub 访问密码

既然要想 docker hub 推送镜像那就必须要 docker hub 的认证配置，如退四步添加配置

3 上代码实战

3.1 创建一个 workflow

3.2 选择模板，这里先随便选一个，后续直接替换

3.3 修改 workflow file,保存运行

# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-maven

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.

name: CI

on:
  push:
    branches: 
      - "master"
    tags:
      - 'v*'
  pull_request:
    branches: [ "master" ]

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ''
  # github.repository as <account>/<repo>
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build:

    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v3
    - name: Set up JDK 8
      uses: actions/setup-java@v3
      with:
        java-version: '8'
        distribution: 'temurin'
        cache: maven
    - name: Build with Maven
      run: mvn -B clean package --file pom.xml
    - name: Build the Docker image
      run: docker build . --file Dockerfile --tag ${{env.IMAGE_NAME}}
    - name: echo
      run: echo $GITHUB_REF_NAME
      
    # 登录  
    - name: Log into registry ${{ env.REGISTRY }}
      if: github.event_name != 'pull_request'
      uses: docker/login-action@v2
      with:
          registry: ${{ env.REGISTRY }}
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
    # Extract metadata (tags, labels) for Docker
    # https://github.com/docker/metadata-action
    - name: Extract Docker metadata
      id: meta
      uses: docker/metadata-action@v4
      with:
          images: ${{ env.IMAGE_NAME }}
          tags: |
            # set latest tag for default branch
            type=raw,value=latest,enable={{is_default_branch}}
            # tag event
            type=ref,enable=true,priority=600,prefix=,suffix=,event=tag
   # 推送
    - name: Build and push Docker image
      uses: docker/build-push-action@v3
      with:
        context: .
        push: ${{ github.event_name != 'pull_request' }}
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}

4. workflow 解释

监听 master 和 tag 推送

on:
  push:
    branches: 
      - "master"
    tags:
      - 'v*'
  pull_request:
    branches: [ "master" ]

1. uses: actions/checkout@v3 负责拉取代码
2. actions/setup-java@v3 负责maven编译
3. docker/login-action@v2 负责登录 docker hub
4. docker/metadata-action@v4 负责 修改docker image tag信息
5. docker/build-push-action@v3负责推送 docker镜像

5.最终效果

修改master 上文件，自动推送 docker laster 镜像

推送以v开头tag，自动推送admin4j/alertmanager-dingtalk-webhook:v* 镜像

查看效果https://hub.docker.com/repository/docker/admin4j/alertmanager-dingtalk-webhook/tags

参考

https://docs.github.com/en/actions/quickstart

Github Action 指南

Docker Metadata action