Use local value in variables.tf - terraform

Question

How to use local value in variables.tf?
I need to assign dynamically value to threshold for two of netapp volume metric alert and I get an error: Error: Variables not allowed. Each NetApp Volume has different storage quota in GB, that's why it needs to be dynamic.
NetApp Volume code:
main.tf
locals {
iops_80 = format("%.0f", (var.storage_quota_in_gb * 1.6))
}
resource "azurerm_netapp_volume" "netapp_volume" {
name = var.netapp_vol_name
resource_group_name = var.resource_group_name
location = var.location
account_name = var.account_name
pool_name = var.pool_name
volume_path = var.volume_path
service_level = var.service_level
subnet_id = var.subnet_id
storage_quota_in_gb = var.storage_quota_in_gb
protocols = var.protocols
dynamic "export_policy_rule" {
for_each = var.export_policy_rules
content {
rule_index = export_policy_rule.value.rule_index
allowed_clients = export_policy_rule.value.allowed_clients
protocols_enabled = export_policy_rule.value.protocols_enabled
unix_read_only = export_policy_rule.value.unix_read_only
unix_read_write = export_policy_rule.value.unix_read_write
}
}
tags = var.tags
}
resource "azurerm_monitor_metric_alert" "alert" {
depends_on = [azurerm_netapp_volume.netapp_volume]
count = length(var.criteria)
name = "HPG-ALRT-${var.netapp_vol_name}-001-${element(keys(var.criteria), count.index)}"
resource_group_name = var.resource_group_name
scopes = [azurerm_netapp_volume.netapp_volume.id]
enabled = var.enabled
auto_mitigate = var.auto_mitigate
description = lookup(var.criteria, element(keys(var.criteria), count.index), null)["description"]
frequency = var.frequency
severity = lookup(var.criteria, element(keys(var.criteria), count.index), null)["severity"]
window_size = var.window_size
criteria {
metric_namespace = lookup(var.criteria, element(keys(var.criteria), count.index), null)["metric_namespace"]
metric_name = lookup(var.criteria, element(keys(var.criteria), count.index), null)["metric_name"]
aggregation = lookup(var.criteria, element(keys(var.criteria), count.index), null)["aggregation"]
operator = lookup(var.criteria, element(keys(var.criteria), count.index), null)["operator"]
threshold = lookup(var.criteria, element(keys(var.criteria), count.index), null)["threshold"]
}
action {
action_group_id = var.action_group_id
}
}
variables.tf
variable "criteria" {
type = map
default = {
"ReadLATENCY5" = {
metric_namespace = "Microsoft.NetApp/netAppAccounts/capacityPools/volumes"
metric_name = "AverageReadLatency"
aggregation = "Average"
operator = "GreaterThan"
threshold = 5
description = "NetApp: Volume Read Latency over 5ms"
severity = 2
},
"ReadIOPS80" = {
metric_namespace = "Microsoft.NetApp/netAppAccounts/capacityPools/volumes"
metric_name = "ReadIops"
aggregation = "Average"
operator = "GreaterThan"
threshold = local.iops_80
description = "NetApp: Volume Read IOPS over TBD"
severity = 2
},
"WriteIops80" = {
metric_namespace = "Microsoft.NetApp/netAppAccounts/capacityPools/volumes"
metric_name = "WriteIops"
aggregation = "Average"
operator = "GreaterThan"
threshold = local.iops_80
description = "NetApp: Volume Write IOPS over TBD"
severity = 2
},
}
}
One way is to do another criteria map to define only alerts with iops_80 value and assign it in main.tf but is there any other way to do it?

Answer 1

It seems you cannot use the local values in the variables file. What you can do is that use the variables in the local, and use the local value and variables in the resource block. And you can also use the local values in another local.
So I think you need to use the variables to set the input and things would be changed. And quote the variables in the local or quote the local in another local. For example, maybe you can use the local to set the criteria instead of using a variable.