BaseSNSArn calculates the base SNS arn given an instance's arn.

DetectARNPrefix uses the EC2 metadata API to determine the current prefix.

GetRegionFromARN is a helper function to get region from ARNs.

InstanceProfileArn uses the EC2 metadata API to find the role for the instance.

ValidateARN is a helper function to validate ARNs.

ValidateRegionString is a helper function to validate the region string.