variable "middle_in" {
  type = map(string)
  default = {
    eu-west-1 = "ami-12345"
    eu-west-2 = "ami-67890"
  }
}

module "inner" {
  source = "../inner"

  inner_in = "hello"
}

resource "null_resource" "middle_noop" {}

output "middle_out" {
  value = lookup(var.middle_in, "us-west-1")
}