├── .github
│   ├── actions
│   │   └── image-tag-update
│   │       └── action.yaml
│   └── workflows
│       ├── build-go.yaml
│       ├── build-java.yaml
│       ├── build-node.yaml
│       └── kubectl.yaml
├── go-app
│   ├── src/
│   └── Dockerfile
├── java-app
│   ├── src/
│   └── Dockerfile
├── k8s
│   ├── service-go.yaml
│   ├── service-java.yaml
│   ├── service-node.yaml
│   └── kustomization.yaml
└── node-app
    ├── src/
    └── Dockerfile

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app
spec:
...
  template:
...
    spec:
      containers:
      - name: some-server
        image: go-placeholder # placeholderとしてkustomizationと同じ文字列を入れておく

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
namespace: techblog
resources:
  - service-go.yaml
  - service-java.yaml
  - service-node.yaml
images:
  - name: go-placeholder
    newName: go-app
    newTag: v1.1.1
  - name: java-placeholder
    newName: java-app
    newTag: v2.7.9alpha
  - name: node-placeholder
    newName: node-app
    newTag: latest

name: kubectl

on:
  pull_request:
    branches:
    - "**"
    paths:
    - "k8s/**" #Kubernetesのmanifest fileが入っている場所
  push:
    branches:
    - main
    paths:
    - "k8s/**"

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
    - uses: azure/setup-kubectl@v4
    - env:
        KUBECONFIG_CONTENTS: ${{ secrets.KUBECONFIG_CONTENTS }} #事前にkubeconfigをGitHubのシークレットに格納しておく
      run: |
        echo "${KUBECONFIG_CONTENTS}" > $HOME/.kube/config
        chmod 600 $HOME/.kube/config
    - run: kubectl apply --dry-run=server -k ./k8s  >> $GITHUB_STEP_SUMMARY

    - if: github.ref == 'refs/heads/main # mainブランチだったら実際に適用
      run: kubectl apply -k k8s/

name: image-tag-update
description: 'コンテナイメージの更新時にkustomizationのイメージタグを書き換えるタスク'
inputs:
  target_app:
    description: '対象のアプリケーション'
    required: true
  tag_value:
    description: '新しいコンテナイメージタグ'
    required: true
  token:
    description: 'PRや内容の更新の権限を持ったトークン'
    required: true
runs:
  using: 'composite'
  steps:
    - uses: actions/checkout@v4
      id: check-branch-exists
      continue-on-error: true
      with:
        ref: "image-tag-update" # タグ更新用のデフォルトブランチ名
    - uses: actions/checkout@v4 # checkoutはブランチが存在しないとデフォルトブランチにフォールバック、みたいなことはできないのでこういう書き方
      if: steps.check-branch-exists.outcome == 'failure'
      with:
        ref: main
    - uses: mikefarah/yq@master # yqで対象のplaceholderのタグの値を置換
      with:
      cmd: yq eval '(.images[] | select(.name == "'"${{ inputs.target_app }}-placeholder"'")).newTag = "'"${{ inputs.tag_value }}"'"' -i k8s/kustomization.yaml
    - uses: peter-evans/create-pull-request@v6
      if: steps.check-branch-exists.outcome == 'failure' # プルリクエストがないと新しいプルリクエストを作成
      with:
        title: 'コンテナイメージの更新'
        body: |
           `${{ inputs.target_app }}`　を更新します
        branch: "image-tag-update"
    - uses: stefanzweifel/git-auto-commit-action@v5
      if: steps.check-branch-exists.outcome == 'success' #　チェックアウトが成功したら、既存のブランチにコミットを追加
      with:
        commit_message: "Image update for ${{ inputs.target_app }}"

...
      - uses: docker/setup-buildx-action@v3
      - uses: docker/build-push-action@v6
        with:
          file: ./Dockerfile
          push: true
          tags: ${{ env.tag }} # なにかしらのタグ
      - uses: ./.github/actions/image_update
        if: github.ref == 'refs/heads/main'
        with:
          target_app: go
          tag_value: ${{ env.tag }}
          token: ${{ secrets.GITHUB_TOKEN }} # コンテンツ、プルリクエスト編集権限を持ったgithub token

  - name: go-placeholder
    newName: go-app
-    newTag: v1.1.1
+    newTag: v1.1.2