publish metric for nightly build failures

Author: ezhang6811

.github/workflows/nightly-build.yml

@@ -9,6 +9,7 @@ on:
       - zhaez/nightly-build
 
 env:
+  AWS_DEFAULT_REGION: us-east-1
   BRANCH_NAME: nightly-dependency-updates
 
 jobs:
@@ -117,4 +118,28 @@ jobs:
       id-token: write
       contents: read
     with:
-      ref: nightly-dependency-updates
+      ref: nightly-dependency-updates
+
+  publish-nightly-build-status:
+    name: "Publish Nightly Build Status"
+    needs: [ update-and-create-pr, build-and-test ]
+    runs-on: ubuntu-latest
+    if: always()
+    steps:
+      - name: Configure AWS Credentials for emitting metrics
+        uses: aws-actions/configure-aws-credentials@a03048d87541d1d9fcf2ecf528a4a65ba9bd7838 #5.0.0
+        with:
+          role-to-assume: ${{ secrets.MONITORING_ROLE_ARN }}
+          aws-region: ${{ env.AWS_DEFAULT_REGION }}
+
+      - name: Publish nightly build status
+        run: |
+          if [[ "${{ needs.build-and-test.result }}" == "skipped" ]]; then
+            echo "Build was skipped (no changes), not publishing metric"
+          else
+            value="${{ needs.build-and-test.result == 'success' && '0.0' || '1.0'}}"
+            aws cloudwatch put-metric-data --namespace 'ADOT/GitHubActions' \
+              --metric-name Failure \
+              --dimensions repository=${{ github.repository }},branch=${{ github.ref_name }},workflow=nightly_build \
+              --value $value
+          fi