Terraform -

Conditionals

Conditional definitions can be quite unintuitive in Terraform.

variable "environment" {
  description = "Deployment environment; dev, qa or production"
  type        = string
  default     = "dev"
}

variable "create_hosted_zone" {
  type        = bool
  default     = false
}

variable "domain" {
  type        = string
}

# creates a new hosted zone
resource "aws_route53_zone" "primary" {
  count = var.create_hosted_zone ? 1 : 0
  name  = var.domain
}

# uses an existing hosted zone
data "aws_route53_zone" "primary" {
  count = var.create_hosted_zone ? 0 : 1
  name  = var.domain
}

locals {
  hosted_zone_id = var.create_hosted_zone ? aws_route53_zone.primary[0].zone_id : data.aws_route53_zone.primary[0].zone_id
  subdomain      = var.environment == "production" ? "" : "${var.environment}."
}

resource "aws_route53_record" "root" {
  zone_id = local.hosted_zone_id
  name    = "${local.subdomain}${var.domain}"
  type    = "A"
  alias {
    name                   = aws_lb.primary.dns_name
    zone_id                = aws_lb.primary.zone_id
    evaluate_target_health = true
  }
}