CIDR to IP range in order to use in a firewall definition, that does not understand CIDRs (like azurerm_sql_firewall_rule)?

Question

I have a bunch of CIDRs which I need to feed to azurerm_sql_firewall_rule. Unfortunately, the latter needs <start IP, end IP> pair.

Is there a way to do it in terraform?

Answer 1

Figured it out:

locals {
  cidr = "10.12.127.0/20"
  bits = 32 - split("/", local.cidr)[1]
  x = cidrhost(local.cidr, 0)
  y = cidrhost(local.cidr, pow(2, local.bits) - 1)
}

output "x" {
    value = local.x
}

output "y" {
    value = local.y
}

Running it:

Outputs:

x = 10.12.112.0
y = 10.12.127.255