preview-link.yml

name: Vercel deployment preview link generator

on:
  pull_request:
    types: [opened, synchronize]
    paths:
      - 'website/docs/docs/**'
      - 'website/docs/best-practices/**'
      - 'website/docs/guides/**'
      - 'website/docs/faqs/**'
      - 'website/docs/reference/**'

permissions:
  contents: write
  pull-requests: write

jobs:
  update-pr-description:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install necessary tools
        run: |
          sudo apt-get update
          sudo apt-get install -y jq curl

      - name: Generate Vercel deployment URL
        id: vercel_url
        run: |
          # Get the branch name
          BRANCH_NAME="${{ github.head_ref }}"

          # Convert to lowercase
          BRANCH_NAME_LOWER=$(echo "$BRANCH_NAME" | tr '[:upper:]' '[:lower:]')

          # Replace non-alphanumeric characters with hyphens
          BRANCH_NAME_SANITIZED=$(echo "$BRANCH_NAME_LOWER" | sed 's/[^a-z0-9]/-/g')

          # Construct the deployment URL
          DEPLOYMENT_URL="https://docs-getdbt-com-git-${BRANCH_NAME_SANITIZED}-dbt-labs.vercel.app"

          echo "deployment_url=$DEPLOYMENT_URL" >> $GITHUB_OUTPUT

      - name: Wait for deployment to be accessible
        id: wait_for_deployment
        run: |
          DEPLOYMENT_URL="${{ steps.vercel_url.outputs.deployment_url }}"
          echo "Waiting for deployment at $DEPLOYMENT_URL to become accessible..."

          MAX_ATTEMPTS=60  # Wait up to 10 minutes
          SLEEP_TIME=10    # Check every 10 seconds
          ATTEMPTS=0

          while [ $ATTEMPTS -lt $MAX_ATTEMPTS ]; do
            STATUS_CODE=$(curl -s -o /dev/null -w "%{http_code}" "$DEPLOYMENT_URL")
            if [ "$STATUS_CODE" -eq 200 ]; then
              echo "Deployment is accessible."
              break
            else
              echo "Deployment not yet accessible (status code: $STATUS_CODE). Waiting..."
              sleep $SLEEP_TIME
              ATTEMPTS=$((ATTEMPTS + 1))
            fi
          done

          if [ $ATTEMPTS -eq $MAX_ATTEMPTS ]; then
            echo "Deployment did not become accessible within the expected time."
            exit 1
          fi  

      - name: Get changed files
        id: files
        run: |
          CHANGED_FILES=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.sha }} | grep -E '^website/docs/(docs|best-practices|guides|faqs|reference)/.*\.md$' || true)
          if [ -z "$CHANGED_FILES" ]; then
            echo "No documentation files were changed."
            echo "changed_files=" >> $GITHUB_OUTPUT
          else
            CHANGED_FILES=$(echo "$CHANGED_FILES" | tr '\n' ' ')
            echo "changed_files=$CHANGED_FILES" >> $GITHUB_OUTPUT
          fi

      - name: Generate file preview links
        id: links
        run: |
          DEPLOYMENT_URL="${{ steps.vercel_url.outputs.deployment_url }}"
          CHANGED_FILES="${{ steps.files.outputs.changed_files }}"

          if [ -z "$CHANGED_FILES" ]; then
            echo "No changed files found in the specified directories."
            LINKS="No documentation files were changed."
          else
            LINKS=""
            # Convert CHANGED_FILES back to newline-separated for processing
            CHANGED_FILES=$(echo "$CHANGED_FILES" | tr ' ' '\n')
            for FILE in $CHANGED_FILES; do
              # Remove 'website/docs/' prefix
              FILE_PATH="${FILE#website/docs/}"
              # Remove the .md extension
              FILE_PATH="${FILE_PATH%.md}"

              # Construct the full URL
              FULL_URL="$DEPLOYMENT_URL/$FILE_PATH"
              LINKS="$LINKS\n- $FULL_URL"
            done
          fi

          # Properly set the multi-line output
          echo "links<<EOF" >> $GITHUB_OUTPUT
          echo -e "$LINKS" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Update PR description with deployment links
        uses: actions/github-script@v6
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const prNumber = context.issue.number;

            // Fetch the current PR description
            const { data: pullRequest } = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: prNumber,
            });

            let body = pullRequest.body || '';

            // Define the markers
            const startMarker = '<!-- vercel-deployment-preview -->';
            const endMarker = '<!-- end-vercel-deployment-preview -->';

            // Get the deployment URL and links from environment variables
            const deploymentUrl = process.env.DEPLOYMENT_URL;
            const links = process.env.LINKS;

            // Build the deployment content without leading whitespace
            const deploymentContent = [
              `${startMarker}`,
              '---',
              '🚀 Deployment available! Here are the direct links to the updated files:',
              '',
              `${links}`,
              '',
              `${endMarker}`
            ].join('\n');

            // Remove existing deployment content between markers
            const regex = new RegExp(`${startMarker}[\\s\\S]*?${endMarker}`, 'g');
            body = body.replace(regex, '').trim();

            // Append the new deployment content
            body = `${body}\n\n${deploymentContent}`;

            // Update the PR description
            await github.rest.pulls.update({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: prNumber,
              body: body,
            });
        env:
          DEPLOYMENT_URL: ${{ steps.vercel_url.outputs.deployment_url }}
          LINKS: ${{ steps.links.outputs.links }}