adding resource group creation option

Author: kumarvna

main.tf

@@ -2,65 +2,76 @@
 # Local declarations
 #---------------------------
 locals {
-  frontend_port_name             = "appgw-${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}-feport"
-  frontend_ip_configuration_name = "appgw-${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}-feip"
-  gateway_ip_configuration_name  = "appgw-${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}-gwipc"
+  frontend_port_name             = "appgw-${var.app_gateway_name}-${local.location}-feport"
+  frontend_ip_configuration_name = "appgw-${var.app_gateway_name}-${local.location}-feip"
+  gateway_ip_configuration_name  = "appgw-${var.app_gateway_name}-${local.location}-gwipc"
+
+  resource_group_name = element(coalescelist(data.azurerm_resource_group.rgrp.*.name, azurerm_resource_group.rg.*.name, [""]), 0)
+  location            = element(coalescelist(data.azurerm_resource_group.rgrp.*.location, azurerm_resource_group.rg.*.location, [""]), 0)
 }
 
 #----------------------------------------------------------
 # Resource Group, VNet, Subnet selection & Random Resources
 #----------------------------------------------------------
-data "azurerm_resource_group" "rg" {
-  name = var.resource_group_name
+data "azurerm_resource_group" "rgrp" {
+  count = var.create_resource_group == false ? 1 : 0
+  name  = var.resource_group_name
+}
+
+resource "azurerm_resource_group" "rg" {
+  count    = var.create_resource_group ? 1 : 0
+  name     = lower(var.resource_group_name)
+  location = var.location
+  tags     = merge({ "ResourceName" = format("%s", var.resource_group_name) }, var.tags, )
 }
 
 data "azurerm_virtual_network" "vnet" {
   name                = var.virtual_network_name
-  resource_group_name = data.azurerm_resource_group.rg.name
+  resource_group_name = var.vnet_resource_group_name == null ? local.resource_group_name : var.vnet_resource_group_name
 }
 
 data "azurerm_subnet" "snet" {
   name                 = var.subnet_name
   virtual_network_name = data.azurerm_virtual_network.vnet.name
-  resource_group_name  = data.azurerm_resource_group.rg.name
+  resource_group_name  = data.azurerm_virtual_network.vnet.resource_group_name
 }
 
 data "azurerm_log_analytics_workspace" "logws" {
   count               = var.log_analytics_workspace_name != null ? 1 : 0
   name                = var.log_analytics_workspace_name
-  resource_group_name = data.azurerm_resource_group.rg.name
+  resource_group_name = local.resource_group_name
 }
 
 data "azurerm_storage_account" "storeacc" {
   count               = var.storage_account_name != null ? 1 : 0
   name                = var.storage_account_name
-  resource_group_name = data.azurerm_resource_group.rg.name
+  resource_group_name = local.resource_group_name
 }
 
 #-----------------------------------
 # Public IP for application gateway
 #-----------------------------------
 resource "azurerm_public_ip" "pip" {
-  name                = lower("${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}-gw-pip")
-  location            = data.azurerm_resource_group.rg.location
-  resource_group_name = data.azurerm_resource_group.rg.name
+  name                = lower("${var.app_gateway_name}-${local.location}-gw-pip")
+  location            = local.location
+  resource_group_name = local.resource_group_name
   allocation_method   = var.sku.tier == "Standard" ? "Dynamic" : "Static"
   sku                 = var.sku.tier == "Standard" ? "Basic" : "Standard"
   domain_name_label   = var.domain_name_label
-  tags                = merge({ "ResourceName" = lower("${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}-gw-pip") }, var.tags, )
+  tags                = merge({ "ResourceName" = lower("${var.app_gateway_name}-${local.location}-gw-pip") }, var.tags, )
 }
 
 #----------------------------------------------
 # Application Gateway with all optional blocks
 #----------------------------------------------
 resource "azurerm_application_gateway" "main" {
-  name                = lower("appgw-${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}")
-  resource_group_name = data.azurerm_resource_group.rg.name
-  location            = data.azurerm_resource_group.rg.location
+  name                = lower("appgw-${var.app_gateway_name}-${local.location}")
+  resource_group_name = local.resource_group_name
+  location            = local.location
   enable_http2        = var.enable_http2
   zones               = var.zones
   firewall_policy_id  = var.firewall_policy_id != null ? var.firewall_policy_id : null
-  tags                = merge({ "ResourceName" = lower("appgw-${var.app_gateway_name}-${data.azurerm_resource_group.rg.location}") }, var.tags, )
+  tags                = merge({ "ResourceName" = lower("appgw-${var.app_gateway_name}-${local.location}") }, var.tags, )
 
   sku {
     name     = var.sku.name

variables.tf

@@ -1,3 +1,8 @@
+variable "create_resource_group" {
+  description = "Whether to create resource group and use it for all networking resources"
+  default     = false
+}
+
 variable "resource_group_name" {
   description = "A container that holds related resources for an Azure solution"
   default     = ""
@@ -13,6 +18,11 @@ variable "virtual_network_name" {
   default     = ""
 }
 
+variable "vnet_resource_group_name" {
+  description = "The resource group name where the virtual network is created"
+  default     = null
+}
+
 variable "subnet_name" {
   description = "The name of the subnet to use in VM scale set"
   default     = ""