Tell Terraform to ignore Route53 resource in different workspace - amazon-web-services

Question

I currently have 2 workspaces within Terraform, one for Prod and one for Dev.
In prod my Terraform code creates a Route53 entry and then add's a cert as a CNAME to the Route53 hosted zone and then attaches the cert to my load balancer.
resource "aws_acm_certificate" "default" {
domain_name = "www.test.uk"
validation_method = "DNS"
}
resource "aws_route53_record" "validation" {
name = aws_acm_certificate.default.domain_validation_options[0].resource_record_name
type = aws_acm_certificate.default.domain_validation_options[0].resource_record_type
zone_id = "Z0725470IF9R8J77LPTU"
records = [
aws_acm_certificate.default.domain_validation_options[0].resource_record_value]
ttl = "60"
}
resource "aws_acm_certificate_validation" "default" {
certificate_arn = aws_acm_certificate.default.arn
validation_record_fqdns = [
aws_route53_record.validation.fqdn,
]
}
When I switch my workspace to dev and run terraform apply it tries to creates this Route53 entry again and errors. Is there a way to tell Terraform to ignore this?
I tried adding a count of 0 but it gave me this error
Error: Missing resource instance key
on alb.tf line 12, in resource "aws_route53_record" "validation":
12: type =
aws_acm_certificate.default.domain_validation_options[0].resource_record_type
Because aws_acm_certificate.default has "count" set, its attributes
must be accessed on specific instances.
For example, to correlate with indices of a referring resource, use:
aws_acm_certificate.default[count.index]
Error: Missing resource instance key
on alb.tf line 15, in resource "aws_route53_record" "validation":
15:
aws_acm_certificate.default.domain_validation_options[0].resource_record_value]
Because aws_acm_certificate.default has "count" set, its attributes
must be accessed on specific instances.
For example, to correlate with indices of a referring resource, use:
aws_acm_certificate.default[count.index]
The best solution I've come up with is to comment out the Route53 stuff when I run terraform apply in the staging workspace, this obviously isn't an ideal solution.

Answer 1

Untested below but I think you can use a conditional (based on your workspace name) and use count to create (or not create) the resources.
locals {
create_me = terraform.workspace == "dev" ? 0 : 1
}
resource "aws_acm_certificate" "default" {
count = local.create_me
domain_name = "www.test.uk"
validation_method = "DNS"
}
resource "aws_route53_record" "validation" {
count = local.create_me
name = aws_acm_certificate.default.domain_validation_options[count.index].resource_record_name
type = aws_acm_certificate.default.domain_validation_options[count.index].resource_record_type
zone_id = "Z0725470IF9R8J77LPTU"
records = [
aws_acm_certificate.default.domain_validation_options[count.index].resource_record_value]
ttl = "60"
}
resource "aws_acm_certificate_validation" "default" {
count = local.create_me
certificate_arn = aws_acm_certificate.default[count.index].arn
validation_record_fqdns = [
aws_route53_record.validation[count.index].fqdn,
]
}