如何从 cloudformation 中的现有表中引用 dynamodb stream arn？

Question

I have a dynamodb table in one region (Singapore) which was created by a global table from another region (Sydney). So there is no cloudformation stack for the table in Singapore region. I am going to deploy a lambda which enable streams from the table in Singapore. The question is how can I reference the stream arn in the cloudformation when I deploy the lambda?

Answer 1

There's two main approaches:

1. Pass the Stream ARN as a parameter to the CloudFormation stack when you create it
2. Write a Custom Resource (Lambda-function) to query the Stream ARN and return it. Then write your actual Lambda trigger based on the output of the custom resource