Populate Azure Resource Group Creator Tags using Event Grid & Azure Functions at scale!

For my new job as Product Owner for Cloud foundation, I need a solution that could add creator name and date time as tags to the resource group, no matter how it was created.
I search the net and found a nice blog post about tagging all resources this using

• Azure Functions
• Event Grid Subscription

This enables the function to be triggered on specific events in Azure.
The blog post can be found here
in my case I only want to tag RGs for now, but since we have many resource groups and I wanted it to use as little consumption as possible, I re-wrote it from PowerShell to C#.

The source code is available on my github page
https://github.com/JakobGSvendsen/Az.PopulateTags

It consists of an azure function and arm templates for deploying the event grid subscription (az function template work in progress!)

	// Default URL for triggering event grid function in the local environment.
	// http://localhost:7071/runtime/webhooks/EventGrid?functionName={functionname}
	using System;
	using Microsoft.Azure.WebJobs;
	using Microsoft.Azure.WebJobs.Host;
	using Microsoft.Azure.EventGrid.Models;
	using Azure.Identity;
	using Azure.ResourceManager.Resources;
	using Azure.ResourceManager.Resources.Models;
	using Microsoft.Azure.WebJobs.Extensions.EventGrid;
	using Microsoft.Extensions.Logging;
	using System.Collections.Generic;
	using Newtonsoft.Json;
	using AddAutoTags;
	namespace AddTags
	{
	public static class AddAutoTags
	{
	[FunctionName("AddAutoTags")]
	public static void Run([EventGridTrigger] EventGridEvent eventGridEvent, ILogger log)
	{
	log.LogInformation(eventGridEvent.Data.ToString());
	var dataJObject = (Newtonsoft.Json.Linq.JObject)eventGridEvent.Data;
	var data = dataJObject.ToObject<CustomResourceWriteSuccessData>();
	var resourceUri = data.ResourceUri;
	log.LogInformation(resourceUri);
	//Update tags
	var resourceClient = new ResourcesManagementClient(data.SubscriptionId, new DefaultAzureCredential());
	var tags = new TagsPatchResource
	{
	Operation = TagsPatchResourceOperation.Merge,
	Properties = new Tags()
	};
	log.LogInformation("Add/Update Tag: ModifiedDate");
	tags.Properties.TagsValue.Add("ModifiedDate", DateTimeOffset.Now.ToString());
	log.LogInformation("Add/Update Tag: ModifiedBy");
	tags.Properties.TagsValue.Add("ModifiedBy", data.Claims["name"]);
	tags.Properties.TagsValue.Add("ModifiedById", data.Claims["http://schemas.microsoft.com/identity/claims/objectidentifier"]);
	//Add created by if they are not there
	log.LogInformation("Getting Current Tags");
	var currentTags = resourceClient.Tags.GetAtScope(resourceUri);
	if (!currentTags.Value.Properties.TagsValue.ContainsKey("CreatedBy"))
	{
	log.LogInformation("Add Tag: CreatedBy");
	tags.Properties.TagsValue.Add("CreatedBy", data.Claims["name"]);
	tags.Properties.TagsValue.Add("CreatedById", data.Claims["http://schemas.microsoft.com/identity/claims/objectidentifier"]);
	}
	if (!currentTags.Value.Properties.TagsValue.ContainsKey("CreatedDate"))
	{
	log.LogInformation("Add Tag: CreatedDate");
	tags.Properties.TagsValue.Add("CreatedDate", DateTimeOffset.Now.ToString());
	}
	log.LogInformation("Saving Tags");
	resourceClient.Tags.UpdateAtScope(resourceUri, tags);
	}
	}
	}

view raw AddTags.cs hosted with ❤ by GitHub

Written on September 30, 2020