unused aws instace and vpcs cleanup

Signed-off-by: shiva kumar <shivaku@nvidia.com>

.github/workflows/awscleanup.yaml

@@ -46,9 +46,24 @@ jobs:
             --filters "Name=tag:Name,Values=ci*" \
             --query "Vpcs[].VpcId" \
             --output text | tr -d '\r' | tr '\n' ' ')
+          # Check if the VPC has a main route table
+          old_vpcs=""
+          for vpc in $vpcs; do
+              main_route_table=$(aws ec2 describe-route-tables \
+                  --filters Name=vpc-id,Values=$vpc \
+                  --query "RouteTables[?Associations[?Main==true]].RouteTableId" \
+                  --output text)
+
+              if [ -z "$main_route_table" ]; then
+                  echo "No main route table found for VPC: $vpc. Skipping."
+                  continue
+              fi
 
-          echo "Found VPCs: $vpcs"
-          echo "vpcs=$vpcs" >> $GITHUB_ENV
+              echo "VPC: $vpc is valid for processing."
+              old_vpcs="$old_vpcs $vpc"
+          done
+          echo "Old VPCs: $old_vpcs"
+          echo "vpcs=$old_vpcs" >> $GITHUB_ENV
 
       - name: Terminate EC2 Instances
         if: env.instances != ''