azapi_resource

Introduction

Date	Description
2021-04-29	Azure Web PubSub in Public Preview
2021-08-02	Developers start testing the preview functionality
2021-11-16	Azure Web PubSub goes GA
2021-12-06	Developers ask to include Web PubSub in the Terraform config

The developers would like to have the Web PubSub resource created by Terraform. Unfortunately it is not yet showing as a resource type in the docs for azurerm v2.93.

Still, you know how to drive Web PubSub creation using the REST API. Time to create an azapi_resource as a small proof of concept.

Pre-reqs

1. Azure subscription
2. Microsoft.SignalRService provider is registered
3. Existing resource group

The examples use “myResourceGroup”

Initial configuration

These labs will use a single main.tf file throughout so that all of the changes are in one place. A common convention is to have separate files for Terraform, e.g. provider.tf, variables.tf, main.tf, outputs.tf.

1. Create a working directory

   mkdir ~/azapi-labs
   

2. Change directory

   cd ~/azapi-labs
   

3. Create a main.tf

   Copy in the code block below and save.

   terraform {
     required_providers {
       azurerm = {
         source  = "hashicorp/azurerm"
         version = "=2.93"
       }
     }
   }
   
   provider "azurerm" {
     features {}
   }
   
   resource "azurerm_resource_group" "azapi_labs" {
     name     = "azapi_labs"
     location = "West Europe"
   }
   

   Note that the azurerm provider is pinned to v2.93.

4. Initialise

   terraform init
   

5. Apply

   terraform apply
   

azapi_resource

When creating the azapi_resource, you can either specify the location as an argument or embed it into the JSON.

There are a few options for the JSON body. The recommended approaches are to use either the jsonencode() function, or the file() or templatefile() functions.

In this lab we will use jsonencode, but for large sections of JSON then using files can make your config more readable. See this repo for an example using templatefile() to create a Data Collection Rule for Azure Monitor.

1. Add azapi to the required providers

   Update the required_providers block in main.tf:

   terraform {
     required_providers {
       azurerm = {
         source  = "hashicorp/azurerm"
         version = "=2.93"
       }
   
       azapi = {
         source  = "azure/azapi"
         version = "=0.3.0"
       }
     }
   }
   

2. Add the azapi provider block

   provider "azapi" {}
   

3. Add the azapi_resource block

   resource "azapi_resource" "webpubsub" {
     type      = "Microsoft.SignalRService/WebPubSub@2021-10-01"
     name      = "azapi-labs-richeney"
     parent_id = azurerm_resource_group.azapi_labs.id
     location  = azurerm_resource_group.azapi_labs.location
   
     body = jsonencode({
       sku = {
         name = "Free_F1"
         capacity = 1
       }
     })
   }
   

   ⚠️ You should select a different and globally unique value for name as it forms part of the FQDN.

   Note how the URL maps to the arguments. Here is the REST API URI to match the block:

   https://management.azure.com/subscriptions/2d31be49-d959-4415-bb65-8aec2c90ba62/resourceGroups/azapi_labs/providers/Microsoft.SignalRService/webPubSub/azapi-labs-richeney?api-version=2021-10-01
   

   And here is the original JSON block from the REST API call. Note the change in format to HCL in the resource block above:

   {
     "sku": {
       "name": "Free_F1",
       "capacity": 1
     },
     "location": "westeurope"
   }
   

   The benefit of using jsonencode() is that Terraform will confirm that the output JSON is syntactically valid.

4. Initialise

   terraform init
   

   You need to reinitialise Terraform as you have now included a new provider. The init will download it.

5. Plan

   terraform plan
   

6. Apply

   terraform apply
   

Check

Terraform uses the azapi provider to create the Web PubSub resource.

1. Check for the resource in the portal

   

2. List the identifiers in state

   terraform state list
   

   Example output:

   azapi_resource.webpubsub
   azurerm_resource_group.azapi_labs
   

3. Display the resource attributes from state

   terraform state show azapi_resource.webpubsub
   

   Example output:

   # azapi_resource.webpubsub:
   resource "azapi_resource" "webpubsub" {
       body                      = jsonencode(
           {
               sku = {
                   capacity = 1
                   name     = "Free_F1"
               }
           }
       )
       id                        = "/subscriptions/2ca40be1-7e80-4f2b-92f7-06b2123a68cc/resourceGroups/azapi_labs/providers/Microsoft.SignalRService/WebPubSub/azapi-labs-richeney"
       ignore_casing             = false
       ignore_missing_property   = false
       location                  = "westeurope"
       name                      = "azapi-labs-richeney"
       output                    = jsonencode({})
       parent_id                 = "/subscriptions/2ca40be1-7e80-4f2b-92f7-06b2123a68cc/resourceGroups/azapi_labs"
       schema_validation_enabled = true
       tags                      = {}
       type                      = "Microsoft.SignalRService/WebPubSub@2021-10-01"
   }
   

Summary

You have successfully used the azapi provider to create a resource via the REST API.

Note that you can also use azapi_resource to create child resources. An example would be the Web Pub Sub Hubs. The parent_id in this case would be the Web Pub Sub resource ID rather than the resource ID for the resource group.

Let’s go forward in time a couple of months, to the release of v2.94, and see how to switch from azapi to a native resource definition.

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