ci(actions): add workflow to calculate and surface PR merge rate

.github/workflows/metrics-merge-rate.yml

@@ -0,0 +1,60 @@
+name: Calculate PR Merge Rate
+
+on:
+  schedule:
+    - cron: '0 12 * * 1' # Runs every Monday at 12:00 UTC
+  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@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - 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%" >> $GITHUB_STEP_SUMMARY
+
+      - name: Send message to Slack
+        uses: slackapi/slack-github-action@37ebaef184d7626c5f204ab8d3baff4262dd30f0 # v1.27.0
+        with:
+          payload: |
+            {
+              "username": "🚢 Merge rate",
+              "icon_url": "https://user-images.githubusercontent.com/3360588/192045905-5d9705af-92e2-4432-805e-15db98571e8b.png",
+              "channel": "#carbon-system-notifications",
+              "text": "${{ env.MERGE_MESSAGE }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+          SLACK_WEBHOOK_TYPE: INCOMING_WEBHOOK