Deploy a web app in Azure App Service using Terraform

Azure App Service is a Platform as a Service (PaaS) that is used to build, deploy, and scale enterprise-grade applications such as web apps, mobile apps, logic apps, API apps, and function apps. It supports multiple programming languages and frameworks such as NET, .NET Core, Java, Ruby, Node.js, PHP, Python.

From a developers perspective Azure App Service provides a great platform to develop, deploy and scale applications. However, when it comes to production environments Infrastructure as code (IaC) comes in handy. Terraform is an open-source IaC tool with a consistent CLI that lets you write infrastructure as code using declarative configuration files and also, manage, plan and apply changes to infrastructure versions to reach the required configuration state.

Terraform is a good choice as it reduces manual human error by codifying the application infrastructure. Terraform manages infrastructure across more than 300 public clouds and it provides a reusable, cost-effective, and consistent environment that solves dependencies and version controls. In this article, we will take you through the process of deploying a web app in Azure App Service using Terraform.

To deploy the web app in Azure App Service using Terraform, here are the steps we need to follow:

Create the Resource Group
Create App Service plan and deploy web app

Create the Resource Group:

The first step is to create a resource group using the following terraform code. Any resource that is created must be created within the resource group

terraform {    
  required_providers {    
    azurerm = {    
      source = "hashicorp/azurerm"    
    }    
  }    
} 
   
provider "azurerm" {    
  features {}    
}

resource "azurerm_resource_group" "resource_group" {
  name     = "app-service-rg"
  location = "East US"
}

Create App Service plan and deploy web app

The App Service plan defines the capacity and resources to be shared among one or more app services that are assigned to that plan. Azure WebApp must be associated with an App Service Plan as it specifies the computing resources that are required for the web app to function. The following code creates an app service plan.

resource "azurerm_app_service_plan" "app_service_plan" {
  name                = "example-appserviceplan"
  location            = azurerm_resource_group.resource_group.location
  resource_group_name = azurerm_resource_group.resource_group.name

  sku {
    tier = "Standard"
    size = "S1"
  }
}

And add code for creating app service. Finally, the terraform file looks like the below

terraform {    
  required_providers {    
    azurerm = {    
      source = "hashicorp/azurerm"    
    }    
  }    
} 
   
provider "azurerm" {    
  features {}    
}

resource "azurerm_resource_group" "resource_group" {
  name     = "app-service-rg"
  location = "East US"
}

resource "azurerm_app_service_plan" "app_service_plan" {
  name                = "myappservice-plan"
  location            = azurerm_resource_group.resource_group.location
  resource_group_name = azurerm_resource_group.resource_group.name

  sku {
    tier = "Standard"
    size = "S1"
  }
}

resource "azurerm_app_service" "app_service" {
  name                = "mywebapp-453627 "
  location            = azurerm_resource_group.resource_group.location
  resource_group_name = azurerm_resource_group.resource_group.name
  app_service_plan_id = azurerm_app_service_plan.app_service_plan.id

  #(Optional)
  site_config {
dotnet_framework_version = "v4.0"
    scm_type                 = "LocalGit"
  }
  
  #(Optional)
  app_settings = {
    "SOME_KEY" = "some-value"
  }

}

Now, we should run the following command to initiate terraform.

Command: terraform init