Referencing resource ARNs in environment variables

Hey all,

I searched all over but couldn’t find the answer to the following problem: I am creating a role in resources whose ARN I need to address in a function.
Using !Ref roleForSomething doesn’t work, as it references the name, not the ARN, which AWS doesn’t like. I have a solution that’s working for AWS but unfortunately Serverless can’t make sense of it (business case is using async Textract when a file is uploaded in S3 and then doing something when Textract is finished, which we know by subscribing to a SNS topic that Textract has to publish to:

functions:
  ocr:
    handler: handler.ocr
    events:
      - s3:
          bucket: ${self:custom.bucket}
          event: s3:ObjectCreated:*
          existing: true
    environment:
      SNS_TOPIC: !Ref textractTopic
      SNS_ROLE:
        'Fn::GetAtt': ['iamRole', 'Arn']

  handler.doSomething:
    handler: handler.doSomething
    events:
      - sns:
          arn: !Ref textractTopic
          topicName: ${self:custom.sns-topic}

resources:
  Resources:
    textractTopic:
      Type: AWS::SNS::Topic
      Properties:
        TopicName: ${self:custom.sns-topic}
    iamRole:
      Type: AWS::IAM::Role
      Properties:
        RoleName: ${self:custom.role-name}
        AssumeRolePolicyDocument:
          Version: '2012-10-17'
          Statement:
            - Effect: Allow
              Principal:
                Service:
                  - textract.amazonaws.com
              Action: sts:AssumeRole
        Policies:
          - PolicyName: textratct-sns-publishing
            PolicyDocument:
              Version: '2012-10-17'
              Statement:
                - Effect: Allow
                  Action:
                    - sns:*
                  Resource:
                    - !Ref textractTopic

How du I replace this:

    environment:
      SNS_ROLE:
        'Fn::GetAtt': ['iamRole', 'Arn']

with something that works for Serverless?

Thank you!
Michael

Did you find a solution for this? I am in the same situation