Turn on 'App Service Authentication' for Azure Active Directory from terraform script

Question

Need to turn on 'App Service Authentication' for Active Directory from my terraform script.

When I add the auth_settings section to my azurerm_app_service resource using the client_id of the app_service I am creating I get the error

'self reference not allowed'

Makes sense but then were to I turn on authentication for the item I am creating?

  name                = "${var.prefix}-${var.environment_code}-${var.environment_segment_code}-web"
  location            = "${azurerm_resource_group.my_resource_group.location}"
  resource_group_name = "${azurerm_resource_group.my_resource_group.name}"
  app_service_plan_id = "${azurerm_app_service_plan.my_app_service_plan.id}"

  app_settings = {
    APPINSIGHTS_INSTRUMENTATIONKEY = "${azurerm_application_insights.my_insights.instrumentation_key}"
  }

  tags = {
    my-Environment = "${var.environment}"
    my-Location    = "${var.country}"
    my-Stack       = "${var.stack}"
  }

  lifecycle {
    ignore_changes = [
      "app_settings"
    ]
  }

  auth_settings {
    enabled = true
    active_directory {
      client_id = "${azurerm_app_service.web.client_id}"
    }
    default_provider = "AzureActiveDirectory"
  }
}```

I'd like to have ad authentication enabled for my website when I terraform.

Answer 1

From azurerm_app_service

A active_directory block supports the following:

client_id - (Required) The Client ID of this relying party application. Enables OpenIDConnection authentication with Azure Active Directory.

There is no direct client_id attribute in the azurerm_app_service block, you need to register the App Service app in Azure Active Directory then add the Application (client) ID on the Azure portal in the active_directory block. See the details about configure your App Service app to use Azure Active Directory sign-in .

The Azure Active Directory resources have been split out into a new AzureAD Provider - as such the AzureAD resources within the AzureRM Provider are deprecated and will be removed in the next major version (2.0). You could do it with azuread_application block.

For example, this works for me with Terraform v0.12.5 + provider.azuread v0.5.1 + provider.azurerm v1.32.0

# Configure the Microsoft Azure Active Directory Provider
provider "azuread" {
  version = "~> 0.3"
}

# Create an application
resource "azuread_application" "example" {
  name = "${var.prefix}-app-service"
  homepage                   = "https://${var.prefix}-app-service"
  identifier_uris            = ["https://${var.prefix}-app-service"]
  reply_urls                 = ["https://${var.prefix}-app-service.azurewebsites.net/.auth/login/aad/callback"]
  available_to_other_tenants = false
  oauth2_allow_implicit_flow = true

}

and

 auth_settings  {
     enabled = true 

     active_directory  {
         client_id = "${azuread_application.example.application_id}"
     }
     default_provider = "AzureActiveDirectory"
     issuer = "https://sts.windows.net/xxxxxxx-xxxx-xxx-xxxx-xxxtenantID/"

}

Result