attachWAFpolicy.tf

resource "azurerm_virtual_network" "vnet" {
  name                = "vnet-app"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  address_space       = ["10.1.0.0/16"]
}

resource "azurerm_subnet" "frontend" {
  name                 = "frontend"
  resource_group_name  = azurerm_resource_group.rg.name
  virtual_network_name = azurerm_virtual_network.vnet.name
  address_prefixes     = ["10.1.1.0/24"]
}

resource "azurerm_subnet" "backend" {
  name                 = "backend"
  resource_group_name  = azurerm_resource_group.rg.name
  virtual_network_name = azurerm_virtual_network.vnet.name
  address_prefixes     = ["10.1.2.0/24"]
}

resource "azurerm_public_ip" "example" {
  name                = "example-pip"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location
  allocation_method   = "Static"
  sku                 = "Standard"
}

#create some locals
locals {
  backend_address_pool_name      = "${azurerm_virtual_network.vnet.name}-beap"
  frontend_port_name             = "${azurerm_virtual_network.vnet.name}-feport"
  frontend_ip_configuration_name = "${azurerm_virtual_network.vnet.name}-feip"
  http_setting_name              = "${azurerm_virtual_network.vnet.name}-be-htst"
  listener_name                  = "${azurerm_virtual_network.vnet.name}-httplstn"
  request_routing_rule_name      = "${azurerm_virtual_network.vnet.name}-rqrt"
  redirect_configuration_name    = "${azurerm_virtual_network.vnet.name}-rdrcfg"
  appservice_fqdn                = "${azurerm_app_service.appservice.name}azurewebsites.net"
}

resource "azurerm_application_gateway" "network" {
  name                = "example-appgateway"
  resource_group_name = azurerm_resource_group.rg.name
  location            = azurerm_resource_group.rg.location

  sku {
    name     = "WAF_v2"
    tier     = "WAF_v2"
    capacity = 2
  }

  gateway_ip_configuration {
    name      = "my-gateway-ip-configuration"
    subnet_id = azurerm_subnet.frontend.id
  }
//this is a comment
  frontend_port {
    name = local.frontend_port_name
    port = 80
  }

  frontend_ip_configuration {
    name                 = local.frontend_ip_configuration_name
    public_ip_address_id = azurerm_public_ip.example.id
   
  }
  backend_address_pool {
    name = local.backend_address_pool_name
    fqdns = ["${azurerm_app_service.appservice.name}.azurewebsites.net"]
  }

  backend_http_settings {
    name                  = local.http_setting_name
    cookie_based_affinity = "Disabled"
    port                  = 443
    protocol              = "Https"
    request_timeout       = 60
    host_name             = "${azurerm_app_service.appservice.name}.azurewebsites.net"
  }

  http_listener {
    name                           = local.listener_name
    frontend_ip_configuration_name = local.frontend_ip_configuration_name
    frontend_port_name             = local.frontend_port_name
    protocol                       = "Http"
  }

  request_routing_rule {
    name                       = local.request_routing_rule_name
    rule_type                  = "Basic"
    http_listener_name         = local.listener_name
    backend_address_pool_name  = local.backend_address_pool_name
    backend_http_settings_name = local.http_setting_name
    priority = 1
  }
  #you may want to use variables
  firewall_policy_id = "/subscriptions/1fc00f4d-a938-4e4c-96c5-6446cd536471/resourceGroups/WAF-DevOps-app/providers/Microsoft.Network/applicationGatewayWebApplicationFirewallPolicies/WAF-Devops-wafpolicy"
}