I have created a compute module that has a conditional to create an external IP.

```
resource "google_compute_address" "external" {     
    count = "${var.EXT_IP_CREATE ? 1 : 0}"     
    name = "${var.NAME}-ext-ip"     
    address_type = "EXTERNAL"     
    region = "${var.REGION}"} 

```

Within the compute instance resource block, I have the following network interface configuration:

```
network_interface {     
    network= "${var.NETWORK}"     
    network_ip = "${google_compute_address.internal.address}"         
    access_config {         
         nat_ip = "${var.EXT_IP_CREATE ? google_compute_address.external.address : 0 }"         
        }     
    } 

```

If the resource google\_compute\_address.external has not been created, I need to set nat\_ip to null or in other words 0. 

That looks like it should work but it does not. 

When setting EXT\_IP\_CREATE to true TF succeeds to create the resource. When setting it to false I receive the following error:

```
Error: Error running plan: 1 error(s) occurred:

* module.compute-dbma-dev.google_compute_instance.compute: 1 error(s) occurred:

* module.compute-dbma-dev.google_compute_instance.compute: Resource 'google_compute_address.external' not found for variable 'google_compute_address.external.address'

```

When I explicitly pass nat\_ip = 0 TF recognizes the blank value and successfully creates the compute instances without the external IP.

Im currently on Terraform version Terraform v0.11. There is probably a super simple solution but I am just starting out with conditionals in TF and I getting stuck here.

Thanks in advance!