How to call default list variables in terraform module - google-cloud-platform

Question

I want to call list variables from below code. But, It is throwing error instead after mentioning the default value in variables.tf
Terraform Service Folder (/root/terraform-ukg-smtp).
main.tf
module "google_uig" {
source = "/root/terraform-google-vm/modules/compute_engine_uig"
depends_on = [
module.google_vm
]
project = var.project
count = var.num_instances
zone = var.zone == null ? data.google_compute_zones.available.names[count.index % length(data.google_compute_zones.available.names)] : var.zone
name = "apoc-uig-${random_integer.integer[count.index].result}"
instances = element((module.google_vm[*].google_instance_id), count.index)
named_ports = var.named_ports
}
variables.tf
variable "named_ports" {
description = "Named name and named port"
type = list(object({
port_name = string
port_number = number
}))
default = [{
port_name = "smtp"
port_number = "33"
}]
}
Terraform Core Folder (/root/terraform-google-vm/modules/compute_engine_uig).
main.tf
# Instance Group
resource "google_compute_instance_group" "google_uig" {
count = var.num_instances
project = var.project
zone = var.zone
name = var.name
instances = var.instances
dynamic "named_port" {
for_each = var.named_ports != null ? toset([1]) : toset([])
content {
name = named_port.value.port_name
port = named_port.value.port_number
}
}
}
variables.tf
variable "named_ports" {
description = "Named name and named port"
type = list(object({
port_name = string
port_number = number
}))
default = null
}
ERROR
╷
│ Error: Unsupported argument
│
│ on main.tf line 66, in module "google_uig":
│ 66: port_number = each.value["port_number"]
│
│ An argument named "port_number" is not expected here.

Answer 1

The error actually lies in the file /root/terraform-google-vm/modules/compute_engine_uig/main.tf, which you have not added to your question. But from the error message, I think to know what is wrong.
The resource google_compute_instance_group.google_uig in compute_engine_uig/main.tf should look like this:
resource "google_compute_instance_group" "google_uig" {
other_keys = other_values
dynamic "named_port" {
for_each = var.named_ports
content {
name = named_port.value.name
port = named_port.value.port
}
}
}
From the error message, it seems that you have written
name = named_ports.value.name
i.e., with a plural s instead of
name = named_port.value.name
in the content block.
If this doesn't solve it, please add the file that throws the error.
Edit from 30.05.2022:
Two more problems are now visible:
You set for_each = var.named_ports != null ? toset([1]) : toset([]), which is not correct. You have to iterate over var.named_ports (as I have written above), not over a set containing the number 1. Just copy it word by word from the code above.
Additionaly, you have defined the type of port_number in your variable named_ports as "number", but you have given a string "33". This may be fine for terraform since it does a lot of conversion in the background, but better change it too.