How to reference the latest Stream of a DynamoDB table in a Cloudformation template

Question

I am writing a plugin for the serverless framework, which references a DynamoDB Stream by its ARN. I can construct the DynamoDB tables ARN with the information I have at hand, but I don't know the timestamp part, that would be necessary to build the full stream ARN. I don't have access to the original DynamoDB Cloudformation definition, when I need to reference the Stream ARN, those two things can happen in entirely different templates. All I have is the ARN of the already created DynamoDB at this point.

Is there a way to reference the latest stream via a variable similar to arn:aws:dynamodb:${AWS::Region}::${AWS::AccountId}:table/eventbus-test/stream/${LATEST}?

Or can I build it in another way by means of a serverless configuration or Cloudformation template?

Answer 1

According to the doc. You can access it with the Fn::GetAtt intrinsic function with the StreamArn parameter. For example:

Resources: 
  Table:
    Type: AWS::DynamoDB::Table
    Properties:
      AttributeDefinitions:
      - AttributeName: leaseKey
        AttributeType: S
      KeySchema:
      - KeyType: HASH
        AttributeName: leaseKey
      ProvisionedThroughput:
        ReadCapacityUnits: '1'
        WriteCapacityUnits: '1'
Outputs:
  TableStreamArn:
    Value: !GetAtt Table.StreamArn