Reuse the configuration to create similar resources in Terraform - terraform

Question

I have the below TF file, which will create a function - FirstFunction. This works perfectly.
resource "azurerm_function_app" "**firstfunction**" {
name = **var.firstfunctionname**
location = azurerm_resource_group.resourcegroupX.location
resource_group_name = azurerm_resource_group.resourcegroupX.name
app_service_plan_id = azurerm_app_service_plan.appserviceplan.id
https_only = "true"
client_affinity_enabled = "true"
app_settings = {
NS = azurerm_eventhub_namespace.eventhubns.name
Hub = azurerm_eventhub.**firsteventhub**.name
propertyX = "**firstproperty**"
LogRef = "${azurerm_storage_account.store.primary_blob_endpoint}${azurerm_storage_container.**firstlogs**.name}"
}
}
resource "azurerm_app_service_virtual_network_swift_connection" "**firstvnet**" {
app_service_id = azurerm_function_app.**firstfunction**.id
subnet_id = azurerm_subnet.snet.id
}
In the file, see the section enclosed with ****, which need to be changed to create SecondFunction, ThirdFunction and so on ...
The way i have right now is to create multiple TF files , with the same code copied and change the sections enclosed in **.
I read through the module system but understood the limitation with the module system is that I cannot refer to the other components created in the same TF root module as shown below
For e.g In the TF file, I refer to location as
location = azurerm_resource_group.resourcegroupX.location
If I do it as a module, the location should be refered to as
location = var.location_name where location_name should be defined as a variable. I cannot refer to components created with the same root module.
Can you please suggest a solution where I can create multiple components based on the similar code ? Please note that, in the above example, Im creating 2 resources in a single TF file and both of them are related.

Answer 1

The simplest way is that use the count property in your resources. It can help you create multiple same resources in the same code.
resource "azurerm_function_app" "myfunction" {
count = number_your_need # how many resources you want to create
name = "${var.firstfunctionname}-${count.index}"
location = azurerm_resource_group.resourcegroupX.location
resource_group_name = azurerm_resource_group.resourcegroupX.name
app_service_plan_id = azurerm_app_service_plan.appserviceplan.id
https_only = "true"
client_affinity_enabled = "true"
app_settings = {
NS = azurerm_eventhub_namespace.eventhubns.name
Hub = azurerm_eventhub.**firsteventhub**.name
propertyX = "**firstproperty**"
LogRef = "${azurerm_storage_account.store.primary_blob_endpoint}${azurerm_storage_container.**firstlogs**.name}"
}
}
resource "azurerm_app_service_virtual_network_swift_connection" "**firstvnet**" {
count = number # how many you need to create
app_service_id = element(azurerm_function_app.myfunction[*].id, count.index)
subnet_id = azurerm_subnet.snet.id
}
The same solution for the azurerm_eventhub that you need to create. For example:
resource "azurerm_eventhub" "myeventhub" {
count = number # how many you need to create
name = "${var.eventhub_name}-${count.index}"
...
}
Then you can refer it in the function app like this:
app_settings = {
NS = azurerm_eventhub_namespace.eventhubns.name
Hub = element(azurerm_eventhub.myeventhub[*].name, count.index)
propertyX = "**firstproperty**"
LogRef = "${azurerm_storage_account.store.primary_blob_endpoint}${azurerm_storage_container.**firstlogs**.name}"
}
So does all the section enclosed with ****.