separate building from deployment

.github/workflows/deploy.yml

@@ -0,0 +1,42 @@
+# 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:
+    uses: ./.github/workflows/nextjs.yml@main
+    with:
+      should-upload-artifact: true
+
+  # 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

.github/workflows/nextjs.yml

@@ -1,27 +1,16 @@
-# 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
+name: Build Next.js site
 
 on:
-  # Runs on pushes targeting the default branch
-  push:
-    branches: ["main"]
-
-  # Allows you to run this workflow manually from the Actions tab
+  pull_request:
+  workflow_call:
+    inputs:
+      should-upload-artifact:
+        required: false
+        type: boolean
   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
@@ -82,17 +71,6 @@ jobs:
         run: ${{ steps.detect-package-manager.outputs.runner }} next export
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v1
+        if: ${{ github.event_name == 'workflow_call' && inputs.should-upload-artifact }}
         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