GitHub Pages へ Custom GitHub Actions Workflows を使って Next.js (SSG) をデプロイする方法をご紹介します。

背景 GitHub Pages へ Next.js (SSG) をデプロイしたい

GitHub Pages へ Next.js (SSG) をデプロイする設定をしました。

具体的な設定手順は GitHub Pages のデプロイに Custom GitHub Actions Workflows を使用することで、ビルドの成果物の commit が不要になりました | DevelopersIO の記事を参考にしました。

サンプルコード .github/workflows/nextjs.yml

実際に設定した Pull Request は https://github.com/codenote-net/nextjs-blog-starter-sandbox/pull/1 から確認できます。

以下に自動生成されたサンプルコード .github/workflows/nextjs.yml も貼っておきます。

# Sample workflow for building and deploying a Next.js site to GitHub Pages
#
# To get started with Next.js see: https://nextjs.org/docs/getting-started
#
name: Deploy Next.js site to Pages

on:
  # Runs on pushes targeting the default branch
  push:
    branches: ["main"]

  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
permissions:
  contents: read
  pages: write
  id-token: write

# Allow one concurrent deployment
concurrency:
  group: "pages"
  cancel-in-progress: true

jobs:
  # Build job
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3
      - name: Detect package manager
        id: detect-package-manager
        run: |
          if [ -f "${{ github.workspace }}/yarn.lock" ]; then
            echo "manager=yarn" >> $GITHUB_OUTPUT
            echo "command=install" >> $GITHUB_OUTPUT
            echo "runner=yarn" >> $GITHUB_OUTPUT
            exit 0
          elif [ -f "${{ github.workspace }}/package.json" ]; then
            echo "manager=npm" >> $GITHUB_OUTPUT
            echo "command=ci" >> $GITHUB_OUTPUT
            echo "runner=npx --no-install" >> $GITHUB_OUTPUT
            exit 0
          else
            echo "Unable to determine packager manager"
            exit 1
          fi
      - name: Setup Node
        uses: actions/setup-node@v3
        with:
          node-version: "18"
          cache: ${{ steps.detect-package-manager.outputs.manager }}
      - name: Setup Pages
        uses: actions/configure-pages@v3
        with:
          # Automatically inject basePath in your Next.js configuration file and disable
          # server side image optimization (https://nextjs.org/docs/api-reference/next/image#unoptimized).
          #
          # You may remove this line if you want to manage the configuration yourself.
          static_site_generator: next
      - name: Restore cache
        uses: actions/cache@v3
        with:
          path: |
            .next/cache
          # Generate a new cache whenever packages or source files change.
          key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock') }}-${{ hashFiles('**.[jt]s', '**.[jt]sx') }}
          # If source files changed but packages didn't, rebuild from a prior cache.
          restore-keys: |
            ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock') }}-
      - name: Install dependencies
        run: ${{ steps.detect-package-manager.outputs.manager }} ${{ steps.detect-package-manager.outputs.command }}
      - name: Build with Next.js
        run: ${{ steps.detect-package-manager.outputs.runner }} next build
      - name: Static HTML export with Next.js
        run: ${{ steps.detect-package-manager.outputs.runner }} next export
      - name: Upload artifact
        uses: actions/upload-pages-artifact@v1
        with:
          path: ./out

  # Deployment job
  deploy:
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    runs-on: ubuntu-latest
    needs: build
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v1

以上、GitHub Pages へ Custom GitHub Actions Workflows を使って Next.js (SSG) をデプロイする設定をした、現場からお送りしました。