Question

A team wants an output that displays a custom DNS name when the variable custom_dns is set to a non-empty string, but otherwise falls back to the auto-generated endpoint from an AWS resource attribute. They want to avoid nested conditional expressions. Which built-in function best returns the first non-empty value from a list of arguments?

Accepted Answer

coalesce(var.custom_dns, aws_db_instance.main.endpoint)

Answer

concat(var.custom_dns, aws_db_instance.main.endpoint)

Answer

merge(var.custom_dns, aws_db_instance.main.endpoint)

Answer

lookup(var.custom_dns, aws_db_instance.main.endpoint)