build(test env): Shutdown test environments on PR close (#13452)

* Ephemeral env PR close cleanup action

* Add documentation for test envs

.github/workflows/ephemeral-env-pr-close.yml

@@ -0,0 +1,58 @@
+name: Cleanup ephemeral envs (PR close)
+
+on:
+  pull_request_target:
+    types: [closed]
+
+jobs:
+  ephemeral-env-cleanup:
+    name: Cleanup ephemeral envs
+    runs-on: ubuntu-latest
+    steps:
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v1
+        with:
+          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
+          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+          aws-region: us-west-2
+
+      - name: Describe ECS service
+        id: describe-services
+        run: |
+          echo "::set-output name=active::$(aws ecs describe-services --cluster superset-ci --services pr-${{ github.event.number }}-service | jq '.services[] | select(.status == "ACTIVE") | any')"
+
+      - name: Delete ECS service
+        if: steps.describe-services.outputs.active == 'true'
+        id: delete-service
+        run: |
+          aws ecs delete-service \
+          --cluster superset-ci \
+          --service pr-${{ github.event.number }}-service \
+          --force
+
+      - name: Login to Amazon ECR
+        if: steps.describe-services.outputs.active == 'true'
+        id: login-ecr
+        uses: aws-actions/amazon-ecr-login@v1
+
+      - name: Delete ECR image tag
+        if: steps.describe-services.outputs.active == 'true'
+        id: delete-image-tag
+        run: |
+          aws ecr batch-delete-image \
+          --registry-id $(echo "${{ steps.login-ecr.outputs.registry }}" | grep -Eo "^[0-9]+") \
+          --repository-name superset-ci \
+          --image-ids imageTag=pr-${{ github.event.number }}
+
+      - name: Comment (success)
+        if: steps.describe-services.outputs.active == 'true'
+        uses: actions/github-script@v3
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            github.issues.createComment({
+              issue_number: ${{ github.event.number }},
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: 'Ephemeral environment shutdown and build artifacts deleted.'
+            })