main_ag.tf

# This is Terraform examples for Azure Application Gateway
# 2022.01.21 limgongsik.
# Reference : https://faun.pub/build-an-azure-application-gateway-with-terraform-8264fbd5fa42

# Declare of the Provider
terraform {
  required_providers {
    azurerm = {
      source = "hashicorp/azurerm"
      version = "~>2.0"
    }
  }
}
provider "azurerm" {
  features {}
}

resource "azurerm_resource_group" "example" {
  name     = "rg-wus-AGexample"
  location = "West US"   #westus
  tags = {
      date = "2022.01.21",
      owner = "gslim"
  }
}

resource "azurerm_virtual_network" "example" {
  name                = "example-network"
  resource_group_name = azurerm_resource_group.example.name
  location            = azurerm_resource_group.example.location
  address_space       = ["10.254.0.0/16"]
}

resource "azurerm_subnet" "frontend" {
  name                 = "frontend"
  resource_group_name  = azurerm_resource_group.example.name
  virtual_network_name = azurerm_virtual_network.example.name
  address_prefixes     = ["10.254.0.0/24"]
}

resource "azurerm_subnet" "backend" {
  name                 = "backend"
  resource_group_name  = azurerm_resource_group.example.name
  virtual_network_name = azurerm_virtual_network.example.name
  address_prefixes     = ["10.254.2.0/24"]
}

resource "azurerm_public_ip" "example" {
  name                = "example-pip"
  resource_group_name = azurerm_resource_group.example.name
  location            = azurerm_resource_group.example.location
  allocation_method   = "Dynamic"
}

# since these variables are re-used - a locals block makes this more maintainable
locals {
  backend_address_pool_name      = "${azurerm_virtual_network.example.name}-beap"
  frontend_port_name             = "${azurerm_virtual_network.example.name}-feport"
  frontend_ip_configuration_name = "${azurerm_virtual_network.example.name}-feip"
  http_setting_name              = "${azurerm_virtual_network.example.name}-be-htst"
  listener_name                  = "${azurerm_virtual_network.example.name}-httplstn"
  request_routing_rule_name      = "${azurerm_virtual_network.example.name}-rqrt"
  redirect_configuration_name    = "${azurerm_virtual_network.example.name}-rdrcfg"
}

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

  sku {
    name     = "Standard_Small"     #Possible values are Standard_Small, Standard_Medium, Standard_Large, Standard_v2, WAF_Medium, WAF_Large, and WAF_v2.
    tier     = "Standard"           #Possible values are Standard, Standard_v2, WAF and WAF_v2.
    capacity = 2
  }

  #waf_configuration {
  #  enabled          = "true"
  #  firewall_mode    = "Detection"
  #  rule_set_type    = "OWASP"
  #  rule_set_version = "3.0"
  #}

  gateway_ip_configuration {
    name      = "my-gateway-ip-configuration"
    subnet_id = azurerm_subnet.frontend.id
  }

  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
  }

  backend_http_settings {
    name                  = local.http_setting_name
    cookie_based_affinity = "Disabled"
    path                  = "/path1/"
    port                  = 80
    protocol              = "Http"
    request_timeout       = 60
  }

  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
  }

    tags = {
      date = "2022.01.21",
      owner = "gslim"
  }
}

### Display output information
output "example-appgateway-PublicIP" { 
    value = azurerm_public_ip.example.ip_address
}