Use output value from module that has a for_each set - terraform

Question

I had my code setup to export the dynamic private ip address when the VM is created. I did this via an outputs value. Since then, I have updated to tf 0.13 and I'm using a for_each in the module but when I reference this value now I get the below error. I'm not sure how I can export the dynamic private address attribute of the NIC now the for_each has been set to be used in the source_address_prefixes. I understand what the error is saying but not sure on correct way of exporting the value to the object map?
Error: Unsupported attribute
on main.tf line 66, in resource "azurerm_network_security_rule" "fico-app-sr-80":
66: source_address_prefixes = module.fico_web_vm.linux_vm_ips[0]
|----------------
| module.fico_web_vm is object with 1 attribute "web-1"
This object does not have an attribute named "linux_vm_ips".
The outputs.tf file:
output "linux_vm_names" {
value = [azurerm_linux_virtual_machine.virtual_machine.*.name]
}
output "linux_vm_ips" {
value = [azurerm_network_interface.network_interface.*.private_ip_address]
}
output "linux_vm_nsg" {
value = azurerm_network_security_group.network_security_group.name
}
Security rule where the error is referencing, located in the main.tf:
resource "azurerm_network_security_rule" "fico-app-sr-80" {
name = "nsr-${var.environment}-${var.directorate}-${var.business_unit}-${var.vm_identifier}${var.instance_number}-http80"
priority = 100
direction = "Inbound"
access = "Allow"
protocol = "*"
source_port_range = "*"
destination_port_range = "80"
source_address_prefixes = module.fico_web_vm.linux_vm_ips[0]
destination_address_prefix = "VirtualNetwork"
resource_group_name = azurerm_resource_group.rg_dwp_fico_app.name
network_security_group_name = "module.fico_app_vm.linux_vm_nsg"
}
The NIC which is in the root module:
resource "azurerm_network_interface" "network_interface" {
name = "nic-${var.environment}-${var.directorate}-${var.business_unit}-${var.vm_identifier}-${var.vm_name}"
resource_group_name = var.resource_group
location = var.location
enable_ip_forwarding = "false"
enable_accelerated_networking = "false"
ip_configuration {
name = "ipconfig1"
subnet_id = data.azurerm_subnet.dwp_subnet.id
private_ip_address_allocation = "Dynamic"
primary = "true"
}
The module that builds the web_vm in main.tf:
module "fico_web_vm" {
for_each = var.web_servers
source = "../modules/compute/linux_vm"
source_image_id = var.web_image_id
location = var.location
vm_name = each.key
vm_identifier = "${var.vm_identifier}${var.instance_number}"
vm = each.value
disks = each.value["disks"]
resource_group = azurerm_resource_group.rg_dwp_fico_web.name
directorate = var.directorate
business_unit = var.business_unit
environment = var.environment
network_rg_identifier = var.network_rg_identifier
subnet_name = "sub-dwp-${var.environment}-${var.directorate}-${var.business_unit}-fe01"
diag_storage_account_name = var.diag_storage_account_name
ansible_storage_account_name = var.ansible_storage_account_name
ansible_storage_account_key = var.ansible_storage_account_key
log_analytics_workspace_name = var.log_analytics_workspace_name
backup_policy_name = var.backup_policy_name
}
variables for the app in the main.tf:
# Web VM Variables
variable "web_servers" {
description = "Variable for defining each instance"
type = map(object({
size = string
admin_username = string
public_key = string
disks = list(number)
zone_vm = string
zone_disk = list(string)
}))
}
The tfvars file that the variables.tf translates to and which the for_each loops over:
web_servers ={
web-1 = {
size = "Standard_B2s"
admin_username = xxxx
public_key = xxxx
disks = [32, 32]
zone_vm = "1"
zone_disk = ["1"]
}
}

Answer 1

As I see, there two mistakes in your code.
First:
network_security_group_name = "module.fico_app_vm.linux_vm_nsg"
need to change into:
network_security_group_name = module.fico_app_vm.linux_vm_nsg
The double quotes are usually used to set a string when you use them only, not other resources.
Second:
source_address_prefixes = module.fico_web_vm.linux_vm_ips[0]
need to change into:
source_address_prefixes = module.fico_web_vm.linux_vm_ips
and the output also should be change into:
output "linux_vm_ips" {
value = azurerm_network_interface.network_interface.*.private_ip_address
}
I see you just create one NIC without count and for_each, but when you set the value with azurerm_network_interface.network_interface.*.private_ip_address then it also returns a list. And the source_address_prefixes option expects a list, so you just need to give the output.
Maybe it's better to change the output like this:
output "linux_vm_ip" {
value = azurerm_network_interface.network_interface.private_ip_address
}
And then you can set the source_address_prefixes like this:
source_address_prefixes = [ module.fico_web_vm.linux_vm_ip ]