Comparision of numeric values with two variables in Terraform templatefile template

Question

I'm trying to create a rendered file with Terraform's templatefile function.

Here is my code:

variable "prefix" {
  default = "k8s"
}

variable "masters_count" {
  default = 2
}

resource "google_compute_address" "k8s-static-ips" {
  name = "${var.prefix}-${count.index}"
  count = var.num_k8s_nodes
}

locals {
  ips = {
    for k in google_compute_address.k8s-static-ips : k.name => k.address
  }
}

resource "local_file" "AnsibleInventory" {

  content = templatefile("inventory.ini.tmpl",
  {
    private = local.ips
    prefix = var.prefix
    masters_count = var.masters_count
  }
  )
  filename = "inventory.ini"
}

[all]
%{ for index, ip in private ~}
${prefix}-${index} ansible_host=${ip} 
%{ endfor ~}

[kube-master]
%{ for index, ip in private ~}
%{ if index < masters_count ~}${prefix}-${index}%{ endif ~}
%{ endfor ~}

[calico-rr]

[k8s-cluster:children]
kube-master
kube-node
calico-rr

I have the problem that the %{ if index < masters_count ~} condition does not work, I am getting the Terraform error:

Call to function "templatefile" failed: inventory.ini.tmpl:11,7-12: Invalid
operand; Unsuitable value for left operand: a number is required., and 4 other
diagnostic(s).

Looks like it doesn't know the index variable in the if block. How can I make the comparision of that line possible accessing the index variable?

Answer 1

I solved it differently now.

[kube-master]
%{ for index, ip in private ~}
%{ if tonumber(element(split("-",index),1)) < masters_count ~}${index}
%{ endif ~}
%{ endfor ~}