Terraform does not make it easy to loop through subnet IDs. How can you add multiple subnet ids to the cosmos db azurerm resource virtual_network_rule block? I’m able to pass each subnet id, but this error shows up for all of them:

Can't access attributes on a primitive-typed value (string).

data.tf

#VNETs
data "azurerm_virtual_network" "vss-np-vnet" {
  provider            = azurerm.nonprod
  name                = var.np_vnet_name
  resource_group_name = var.np_net_rg_name
}


#Subnets
data "azurerm_subnet" "np-subnets" {
  provider = azurerm.nonprod
  count                = length(data.azurerm_virtual_network.vss-np-vnet.subnets)
  name                 = data.azurerm_virtual_network.vss-np-vnet.subnets[count.index]
  virtual_network_name = data.azurerm_virtual_network.vss-np-vnet.name
  resource_group_name  = data.azurerm_virtual_network.vss-np-vnet.resource_group_name

}

cosmos_db.tf

###############################################################################################
#                                      Cosmos DB                                              #
###############################################################################################
resource "azurerm_cosmosdb_account" "np-cosmos-db" {
  provider                              = azurerm.nonprod
  name                                  = var.np_cosmos_db_name
  location                              = var.ea2_location
  resource_group_name                   = var.np_rg1_name
  offer_type                            = "Standard"
  kind                                  = "GlobalDocumentDB"
  is_virtual_network_filter_enabled     = true
  network_acl_bypass_for_azure_services = true
  ip_range_filter                       = "104.42.195.92,40.76.54.131,52.176.6.30,52.169.50.45,52.187.184.26"

  tags = merge(var.base_np_tags, { Componet = "Cosmos DB" })

  capacity {
    total_throughput_limit = 4000
  }

  consistency_policy {
    consistency_level       = "Session"
    max_interval_in_seconds = 5
    max_staleness_prefix    = 100
  }

  backup {
    type                = "Periodic"
    interval_in_minutes = 60
    retention_in_hours  = 72
    storage_redundancy  = "Local"
  }

  geo_location {
    location          = var.ea2_location
    failover_priority = 0
  }

  analytical_storage {
    schema_type = "WellDefined"
  }

  dynamic "virtual_network_rule" {
    for_each = data.azurerm_subnet.np-subnets.*.id
    content {
      id   = virtual_network_rule.value.id
      ignore_missing_vnet_service_endpoint = true
    }
  }

}

Errors:

.
.
.
 Error: Unsupported attribute
│
│   on cosmos_db.tf line 46, in resource "azurerm_cosmosdb_account" "np-cosmos-db":
│   46:       id   = virtual_network_rule.value.id
│     ├────────────────
│     │ virtual_network_rule.value is "/subscriptions//resourceGroups/ACE-P-NETWORK-RGP-05/providers/Microsoft.Network/virtualNetworks/vnet_name/subnets/subnet_name"
│
│ Can't access attributes on a primitive-typed value (string).