Executing a powershell script stored as a gist

Introduction

I’ve been using Chocolatey to manage standard software builds for freshly created virtual machines (VM). I use a Mac and that requires me to stand up a Windows VM from time to time (cough Power BI) or I may want to run a SQL Server VM on Azure. Chocolatey allows me to preserve disk space by giving me the ability to writing a config script which I can fire up on a fresh VM and Chocolatey will proceed to download and install all defined software. This gives me the ability to create a VM, fire off a config, do some work and then clean up afterwards.

At some point I’ll write up some posts on Chocolatey as it’s a real time saver.

Objective

I’ve configured my build scripts as Powershell scripts because they install Chocolatey first. This allows me to run the build on a vanilla Windows VM. At present I copy the script to the VM and execute it. The objective is to avoid having to copy the file. My chocolatey scripts are hosted on github, so what I want to do is define a script that will execute the remote script. It’s worth noting, Chocolatey has the ability to fire configs stored as gists (does it? I’m sure it does, I’ll confirm this) but that requires you to have Chocolatey installed first. Using this approach I can fire this on a vanilla VM, have chocolatey install and then install all remaining software.

Building the command

I’ve placed a gist at that simply writes “Hello World” to the console here;

https://gist.github.com/justinjbird/9118a3a5dfdecad19492b3e8ad54f81f

In order to use it in our command we need to get the plain text version. If we add /raw to the end of the URL this will present us with just that;

https://gist.github.com/justinjbird/9118a3a5dfdecad19492b3e8ad54f81f/raw

So now that we’ve defined that, we can fire the gist using Invoke-Expression ;

Invoke-Expression ((New-Object System.Net.WebClient).DownloadString('https://gist.github.com/justinjbird/9118a3a5dfdecad19492b3e8ad54f81f/raw'))

And there you have it!

So changing the URL for my chocolatey script gist, I can now copy and paste the command straight into the command line and kick off my automated builds. There’s probably more I can do to automate this, still learning as I go!