Customers can now reference existing resources that their stacks interact with. This can be used to define interactions with pre-existing resources and resources in other stacks. Any Amazon resource can be added as a reference using its unique Amazon Resource Name (ARN). This allows resources to be placed inside an existing Virtual Private Cloud (VPC) even if it was provisioned using another tool such as Terraform. This capability can also be used to create event subscriptions to existing resources (e.g. S3 bucket) or to implement centralized error reporting by pointing all stack error handlers at a centralized error reporting function.
API documentation is available at https://docs.stackery.io/nodes/ReferencedResource/