Terraform conditional nested attribute

Question

What's the correct syntax to condition a nested attribute in terraform ? For example serverlessv2_scaling_configuration in the config below :

resource "aws_rds_cluster" "example" {
  # ... other configuration ...

  serverlessv2_scaling_configuration {
    max_capacity = 128.0
    min_capacity = 0.5
  }
}

Goal is to be able to create serverless or non-serverless RDS depending of an environment.

Answer 1

You have to use the Terraform dynamic block syntax for that, with a list of size 1 or 0. Assuming var.serverless is a boolean input variable:

resource "aws_rds_cluster" "example" {
  # ... other configuration ...

  dynamic "serverlessv2_scaling_configuration" {
    for_each = var.serverless ? [1] : []
    content {
      max_capacity = 128.0
      min_capacity = 0.5
    }
  }
}