Terraform Lookup returning a block - terraform

Question

I am attempting to only assign a log_config to a subnet, if the subnet name is in the "file_one.tf sample" below. To accomplish the conditional logic I am using the lookup function to only return a "log_config" block if the name matches a name in the variable referenced in "file_one.tf".
The error I am getting is:
An argument named "log_config" is not expected here. Did you mean to define a block type of "log_config"
Would someone please help out with this? Or present a more elegant approach to assigning blocks to resources with conditional logic?
Thank you
# file_one.tf sample
locals {
subnets = {
"one" = {
"name" = "one"
local_config = {
aggregation_interval = "INTERVAL_10_SEC"
metadata = "INCLUDE_ALL_METADATA"
}
}
}
# file_two.tf
resource "google_compute_subnetwork" "network-with-private-secondary-ip-ranges" {
foreach = local.subnets
name = each_value.name
ip_cidr_range = "10.2.0.0/16"
region = "us-central1"
network = google_compute_network.custom-test.id
secondary_ip_range {
range_name = "tf-test-secondary-range-update1"
ip_cidr_range = "192.168.10.0/24"
}
log_config = lookup(each.value, log_config, null)
}

Answer 1

You are attempting to pass a map type as a value for an argument, and the resource schema is expecting a block type and not an argument with a map. You would need a dynamic block for this situation:
dynamic "log_config" {
for_each = lookup(each.value, log_config, [])
content {
aggregation_interval = log_config.value["aggregation_interval"]
metadata = log_config.value["metadata"]
}
}

Answer 2

The key that you want in said map is called local_config, no? When lookup() returns its default value is null, which is also not a block. But here I believe you want to pass in a string key to the lookup function:
# file_two.tf
{
# ...
name = each.value.name
# ...
log_config = lookup(each.value, "local_config", null)
}