metrics-merge-rate.yml

name: Calculate PR Merge Rate

on:
  schedule:
    - cron: '0 1 * * 3' # Runs at 1:00 AM UTC every Wednesday
  workflow_dispatch: # Allows manual runs from the GitHub Actions tab

jobs:
  calculate-merge-rate:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2

      - name: Calculate merge rate
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          REPO: 'carbon-design-system/carbon'
        run: |
          START_DATE=$(date --date="7 days ago" +%Y-%m-%d)
          END_DATE=$(date +%Y-%m-%d)

          echo "Calculating merge rate for the past week ($START_DATE to $END_DATE) for repository $REPO"

          # Get merged PRs within the date range
          MERGED_COUNT=$(gh pr list --repo "$REPO" --state merged --search "merged:$START_DATE..$END_DATE" --limit 1000 | wc -l)
          # Get all PRs created within the date range
          TOTAL_COUNT=$(gh pr list --repo "$REPO" --state all --search "created:$START_DATE..$END_DATE" --limit 1000 | wc -l)

          if [ "$TOTAL_COUNT" -gt 0 ]; then
            MERGE_RATE=$(echo "scale=2; ($MERGED_COUNT / $TOTAL_COUNT) * 100" | bc)
            MERGE_MESSAGE="Merge Rate for the past week: $MERGE_RATE% (Merged PRs: $MERGED_COUNT, Total PRs created: $TOTAL_COUNT)"
          else
            MERGE_MESSAGE="No PRs found in the repository for the past week. Merge Rate: 0% (Merged PRs: $MERGED_COUNT, Total PRs created: $TOTAL_COUNT)"
          fi

          echo "$MERGE_MESSAGE"
          echo "MERGE_MESSAGE=$MERGE_MESSAGE" >> $GITHUB_ENV

          # Write to GitHub Actions Job Summary (markdown)
          echo "## Weekly Merge Rate Summary" >> $GITHUB_STEP_SUMMARY
          echo "- **Date Range**: $START_DATE to $END_DATE" >> $GITHUB_STEP_SUMMARY
          echo "- **Merged PRs**: $MERGED_COUNT" >> $GITHUB_STEP_SUMMARY
          echo "- **Total PRs created**: $TOTAL_COUNT" >> $GITHUB_STEP_SUMMARY
          echo "- **Merge Rate**: $MERGE_RATE%" >> $GITHUB_STEP_SUMMARY

      - name: Send message to Slack
        uses: slackapi/slack-github-action@fcfb566f8b0aab22203f066d80ca1d7e4b5d05b3 # v1.27.1
        with:
          payload: |
            {
              "username": "🚢 Merge rate",
              "icon_url": "https://user-images.githubusercontent.com/3360588/192045905-5d9705af-92e2-4432-805e-15db98571e8b.png",
              "channel": "#carbon-system-notifications",
              "text": "${{ env.MERGE_MESSAGE }}"
            }
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
          SLACK_WEBHOOK_TYPE: INCOMING_WEBHOOK