Add Slack notification to Terraform Github workflow

Author: markgoddard

.github/workflows/terraform-github.yml

@@ -115,3 +115,23 @@ jobs:
       - name: Terraform Apply
         if: github.ref == 'refs/heads/main' && github.event_name == 'push'
         run: terraform apply -auto-approve -input=false
+
+      - name: Send message to Slack via Workflow Builder
+        uses: slackapi/[email protected]
+        with:
+          payload: |
+            {
+              "channel-id": "${{ env.SLACK_CHANNEL_ID }}",
+              "inputs": "${{ env.INPUTS }}",
+              "message": "${{ env.MESSAGE }}",
+              "results-url": "${{ env.RESULTS_URL }}",
+              "workflow-url": "${{ env.WORKFLOW_URL }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+          SLACK_CHANNEL_ID: ${{ vars.SLACK_CHANNEL_ID }}
+          INPUTS: "N/A"
+          MESSAGE: "${{ github.workflow }}/${{ github.job }} GitHub Actions workflow failed :sob:"
+          RESULTS_URL: "N/A"
+          WORKFLOW_URL: "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+        if: failure() && github.ref == 'refs/heads/main' && github.event_name == 'push'