Fix Cloudflare preview workflow for fork PRs

.github/workflows/ci.yml

@@ -6,6 +6,9 @@ on:
   push:
     branches: [main]
 
+permissions:
+  contents: read
+
 env:
   CF_PROJECT_NAME: tech-docs
   CF_BASE_URL: tech-docs-2ac
@@ -36,6 +39,11 @@ jobs:
   build-and-deploy:
     runs-on: ubuntu-latest
     needs: checks
+    if: ${{ github.event_name == 'push' || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) }}
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: write
     steps:
       - name: Checkout 🛎️
         uses: actions/checkout@v4
@@ -72,14 +80,16 @@ jobs:
         env:
           CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CF_ACCOUNT_ID }}
           CLOUDFLARE_API_TOKEN: ${{ secrets.CF_API_TOKEN }}
+        shell: bash
         run: |
+          set -o pipefail
           yarn dlx wrangler@4.7.1 pages deploy --commit-dirty=true --project-name "${CF_PROJECT_NAME}" build ${{ steps.extract_branch.outputs.branch }} | tee output.log
           sed < output.log -n 's#.*Take a peek over at \(.*\)$#specific_url=\1#p' >> $GITHUB_OUTPUT
         id: deploy
 
       - name: Create commit comment
         uses: mshick/add-pr-comment@v2
-        if: ${{ github.event.number != '' }}
+        if: ${{ github.event_name == 'pull_request' }}
         with:
           message: |
             ### Deployed with **Cloudflare Pages** :cloud: :rocket: :ok:

.github/workflows/cloudflare-pr-preview.yml

@@ -0,0 +1,131 @@
+name: cloudflare-pr-preview
+
+on:
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: PR number to deploy
+        required: true
+        type: number
+
+env:
+  CF_PROJECT_NAME: tech-docs
+  CF_BASE_URL: tech-docs-2ac
+
+jobs:
+  build-preview:
+    name: Build PR preview
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+    outputs:
+      preview_url: ${{ steps.pr.outputs.preview_url }}
+      head_label: ${{ steps.pr.outputs.head_label }}
+    steps:
+      - name: Validate pull request
+        id: pr
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR_NUMBER: ${{ inputs.pr_number }}
+        shell: bash
+        run: |
+          set -eu
+
+          pr_path="repos/${GITHUB_REPOSITORY}/pulls/${PR_NUMBER}"
+          state="$(gh api "${pr_path}" --jq '.state')"
+          base_ref="$(gh api "${pr_path}" --jq '.base.ref')"
+          head_label="$(gh api "${pr_path}" --jq '.head.label')"
+
+          if [ "${state}" != "open" ]; then
+            echo "PR #${PR_NUMBER} is ${state}, not open."
+            exit 1
+          fi
+
+          if [ "${base_ref}" != "main" ]; then
+            echo "PR #${PR_NUMBER} targets ${base_ref}, not main."
+            exit 1
+          fi
+
+          echo "preview_url=https://pr-${PR_NUMBER}.${CF_BASE_URL}.pages.dev" >> "${GITHUB_OUTPUT}"
+          echo "head_label=${head_label}" >> "${GITHUB_OUTPUT}"
+
+      - name: Checkout PR merge 🛎️
+        uses: actions/checkout@v4
+        with:
+          ref: refs/pull/${{ inputs.pr_number }}/merge
+          fetch-depth: 0
+          persist-credentials: false
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          cache: 'yarn'
+
+      - name: Install ⚙️
+        run: yarn install --frozen-lockfile
+
+      - name: Build 🧱
+        run: yarn build
+
+      - name: Upload preview artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: cloudflare-preview-pr-${{ inputs.pr_number }}
+          path: build
+          if-no-files-found: error
+          retention-days: 3
+
+  deploy-preview:
+    name: Deploy PR preview
+    runs-on: ubuntu-latest
+    needs: build-preview
+    environment: cloudflare-preview
+    permissions:
+      actions: read
+      contents: read
+      issues: write
+      pull-requests: write
+    steps:
+      - name: Download preview artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: cloudflare-preview-pr-${{ inputs.pr_number }}
+          path: build
+
+      - name: Deploy to Cloudflare
+        id: deploy
+        env:
+          CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CF_ACCOUNT_ID }}
+          CLOUDFLARE_API_TOKEN: ${{ secrets.CF_API_TOKEN }}
+          PR_NUMBER: ${{ inputs.pr_number }}
+        shell: bash
+        run: |
+          set -eu
+          set -o pipefail
+
+          npx --yes wrangler@4.7.1 pages deploy --commit-dirty=true --project-name "${CF_PROJECT_NAME}" build --branch "pr-${PR_NUMBER}" | tee output.log
+
+          specific_url="$(sed < output.log -n 's#.*Take a peek over at \(.*\)$#\1#p' | tail -n 1)"
+          echo "preview_url=https://pr-${PR_NUMBER}.${CF_BASE_URL}.pages.dev" >> "${GITHUB_OUTPUT}"
+          echo "specific_url=${specific_url}" >> "${GITHUB_OUTPUT}"
+
+      - name: Comment with preview URL
+        env:
+          GH_TOKEN: ${{ github.token }}
+          PR_NUMBER: ${{ inputs.pr_number }}
+          PREVIEW_URL: ${{ steps.deploy.outputs.preview_url }}
+          SPECIFIC_URL: ${{ steps.deploy.outputs.specific_url }}
+          HEAD_LABEL: ${{ needs.build-preview.outputs.head_label }}
+        shell: bash
+        run: |
+          set -eu
+
+          cat > comment.md <<EOF
+          ### Deployed with **Cloudflare Pages** :cloud: :rocket: :ok:
+          - **URL**: [${PREVIEW_URL}](${PREVIEW_URL})
+          - **Specific**: [${SPECIFIC_URL}](${SPECIFIC_URL})
+          - **Source**: ${HEAD_LABEL}
+          EOF
+
+          gh pr comment "${PR_NUMBER}" --body-file comment.md