Dynamic resource creation with Terraform and CosmosDb Configuration Store

terraform-vnets.tf

data "external" "clusters" {  
   program = ["python", "./cosmosdb_reader.py"]   
   query = {    
     cosmos_endpoint = var.endpoint
     cosmos_key      = var.primary_readonly_master_key
     region          = "centralus"    
     subscription_id = "00000000-0000-0000-0000-000000000000"
     // CosmosDb query function
     data_function   = "get_region_peerings"  
   }
}
resource "azurerm_virtual_network_peering" "centralus_to_eastus" { 
    count = data.external.vnets.result.count
    [...]
}