# git action 實作CI初戰
## 1. 目的
- 新增 tag or release 就 push docker image 到 docker hub
- docker image tag 會使用 git 的 tag name

## 作法
1. 新增 workflows
2. 新增下列設定，[在官網可以找到範例](https://docs.github.com/en/actions/publishing-packages/publishing-docker-images)

name: Docker Image CI

on:
  push:
    tags:
    - '*' # 任何tag都做，也可以寫成 v1.* 之類的
  release:
      types: [published]
jobs:
  push_to_registry:
    name: Push Docker image to Docker Hub
    runs-on: ubuntu-latest
    steps:
      - name: Check out the repo
        uses: actions/checkout@v3
      
      - name: Log in to Docker Hub
        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
        with:
          username: ${{ secrets.DOCKER_USERNAME }} # 要在專案內新增 secret
          password: ${{ secrets.DOCKER_PASSWORD }}
      
      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
        with:
          images: kkrong/ci-test # 需要對應到 docker hub 的 repository
      
      - name: Build and push Docker image
        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }} 
          labels: ${{ steps.meta.outputs.labels }}

### 補充1. 取得 github tag name的一種方式
- [參考github討論文章](https://github.com/orgs/community/discussions/26686#discussioncomment-3396593)

### 補充2. 新增Secret
- [新增方式參考官網](https://docs.github.com/en/actions/security-guides/encrypted-secrets)