Automating automation: updating multiple Azure DevOps pipelines using Powershell scripting

Recently, I had to implement a workaround in the Azure DevOps classic release pipelines. This is relatively simple update - I would need to do next:

1. find release in the Azure DevOps web UI and start release definition editor
2. go into first stage/environment
3. add a new instance of the "Azure Powershell" task into the list of the stage tasks
4. configure this task

• set name
• set Azure subscription
• set Powershell script file path
• set script arguments
• tell the task to use "Latest installed version" of the Azure Powershell module
5. repeat steps 3 and 4 process for 2 other stages/environments in the current release definition
   
   
   
6. repeat previous 5 steps for other 10 pipelines

As you can see, I had extremely tedious task on my hand. I would have to update 11 release pipelines, add and configure 3 * 11 = 33 new tasks. My ballpark estimation for the required "physical" effort became next (assuming I already had prepared strings for copy/paste operations): 

11 pipelines * 3 stages * 16 clicks = 528 mouse clicks

11 pipelines * 3 stages * (3 Ctrl-C + 3 Ctrl-V) = 192 keyboard buttons presses

By the time I finished with the second pipeline, I started to understand that I need to automate this process somehow; otherwise I will make mistakes and kill my wrists (plus the whole process is very boring :-). 

The Azure DevOps REST API is an obvious solution to create automated update process. As with any other API's, there is a learning curve to understand how to authenticate, build requests, parse output, how abstracts connects with each other, etc. Fortunately, I found a "shortcut": Powershell module VSTeam created by Donovan Brown. This module is a Powershell wrapper for Azure DevOps API and really made my life easier. TO start with this module, you can find the details of how to install and configure VSTeam here.

Let's go back to my task - I had 9 more release pipelines to update, and I wanted to automate the whole process for consistency (plus had some coding fun). Since all of the affected pipelines had been created from the same coockie-cutter template release, I knew what I had to do exactly:

1. get task #3 from each stage of my étalon pipeline (stages are different by Azure Service Principal used - "Azure Subscription" of the first screenshot)
2. insert the étalon tasks into all other pipelines as step #3 of the corresponding stages
3. skip already updated pipeline :-)

The result of all this effort is a Powershell script below. I added comments to explain how does it work.

P.S. As an alternative solution, I could convert these pipelines into YAML format, but it is a task for the feature.