Terraform: Can't use programmatic resource names

[dgarstang]

resource "aws_instance" "mongo-cfg01.${var.env_name}.${var.domain_name}" {
    ami = "${var.ami_id}"
    instance_type = "m1.small"
    tags {
        Name = "mongo-cfg01.${var.env_name}.${var.domain_name}"
    }
}

Douglass-MacBook-Pro:terraform doug$ terraform plan -var-file dev.tfvars 
There are warnings and/or errors related to your configuration. Please
fix these before continuing.

Warnings:

  * aws_instance.mongo-cfg01.${var.env_name}.${var.domain_name}: module name can only contain letters, numbers, dashes, and underscores.
This will be an error in Terraform 0.4

Seems I can't use programmatic resource names. We've mapped environments (qa, dev, prod etc) to domain names, e.g.: mongo-cfg01.prod.foobar.com, mongo-cfg01.qa.foobar.com and so on. This means we'd have to have one file per environment, which does not scale.

[armon]

The names in Terraform are just logical for the purposes of referring to them. You want to parameterize the values inside the resource, and not the name itself, so this is by design.

Multiple environments are supported by using different variable and state files.

[dgarstang]

Not a bug.

[yellowmegaman]

Hi! After I've started using modules, this is a problem once again.
For google_dns_record_set managed_zone argument is required.
So after defining zone as module, I cant reference it in records for different zones.

modules/dns-zone/main.tf

resource "google_dns_managed_zone" "dns-zone" {
  name        = "${var.name}"
  dns_name    = "${var.dns_name}"
  description = "${var.description}"
}

dns.tf

module "test0-dns-zone" {
  source      = "modules/dns-zone"
  name        = "test0-zone"
  dns_name    = "test0.im."
  description = "Developer test0 DNS zone"
}
module "test1-dns-zone" {
  source      = "modules/dns-zone"
  name        = "test1-zone"
  dns_name    = "test1.im."
  description = "Developer test1 DNS zone"
}

records.tf

resource "google_dns_record_set" "test1_oktanium_im" {
  name = "test1.${google_dns_managed_zone.dns-zone.dns_name}"
  type = "A"
  ttl  = 60
  managed_zone = "${google_dns_managed_zone.dns-zone.name}"
  rrdatas = [
    "${google_compute_instance.somevm.0.network_interface.0.access_config.0.assigned_nat_ip}",
  ]
}

So, basically all my zones will have dns-zone name.

Maybe modules approach is not the best for zones/records? Or maybe zones as modules should be named.

[ameyaagashe]

The design itself has a flaw if you cannot parametrize it.

[dimisjim]

This should be reopened...

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