Automated Dev Database Branch-Switching with AzureSQL, PowerShell and GitHooks

“Keep it simple, stupid!”
– My year 12 & 13 English Lit. Teacher

Recently I’ve been fascinated with something really cool. A couple of my colleagues at Redgate wrote a GitHook which allows you to easily switch branches using Redgate SQL Clone. You can see the hook here with full instructions – and I thought it was pretty neat.

But it got me thinking – I’ve posted a lot about when people are using just Azure SQL DBs (PaaS), about Masking and DB Change Automation, but when you’re using AzureSQL for Dev and Test DBs as well as Prod, you still don’t have the same agility one would expect from a local copy, like a clone.

But, the above GitHook leverages PowerShell (among some other fancy wizardry) so, what if we could do this exact same thing, using the PowerShell Az module to dynamically create and switch Azure SQL DBs in our own private resource groups every time we checkout a branch?

my hero academia wtf GIF by Funimation

I don’t imagine it would be fast because I’m restricted to using very low tier SQL DBs by my tiny allowance of (as Kendra Little calls them) “Azure Bucks”, but it should absolutely be possible!

So I decided to write a PowerShell script to do just that.

The first question I had to come up with an answer to was, how do I replace the Clone “Image” in this process, because I need something that is effectively a copy of our Production (or as near as possible) environment so we have something to base EVERY copy from – so I created the idea of a Golden Copy within the script; effectively this golden copy could be created by copying masking and copying back down from Production using something like Redgate Data Masker and my scripts here in GitHub but as a stop-gap, if it doesn’t find one in the Resource Group and Server you select, it will simply create one from your Dev DB. Best answer I could think of, you’re welcome to improve it!

All that remained was effectively to go through and just mimic the functionality of the Clone script but using Az: so if you are switching to a new branch where you don’t already have an existing Dev DB, then you get a new copy of Golden. If you’re switching to a branch you’ve checked out before, it renames the DBs to swap you back to the correct branch.

Here is an empty AzureSQL DB called DMDatabase_Dev:

When I now issue the git checkout “feature/newfeature” command it asks me to sign in to my Azure account:

and then gets to work:

And… that was it really.

I now have an Azure SQL DB called DMDatabase_Dev_master as I switched from the master branch, and I have a branch new DMDatabase_Dev DB that I can use for my featurebranch. You’ll notice I didn’t include -b in my git command, let’s assume a colleague is already working on this branch. I can now just update my copy (of my golden copy) with their work:

And we’re good to go!

But now if I switch back to my main branch, the object is gone and I can carry on with work on this branch:

It was really straightforward I can’t believe I haven’t seen this in use in more places, but hey guess what? The PowerShell is yours right here if you want it:

https://github.com/ChrisUnwin/PowerShell/blob/master/Demos/Redgate%20Demos/GitHookAzureSQL.ps1

The pre-requisites for it are:

  • You should have a Dev DB and you should update the values at the top of the script with the Dev DB name, server and resource group it is in
  • The script make reference to and creates a Golden copy DB so that you have something you should always be creating from, for consistency – so when you get started, create your own “Golden copy” back from Test/UAT or something if you can – maybe using the script mentioned above – it should be the name of your Dev DB appended with “_Golden”
  • If you want to change how it is authenticated so you don’t have to enter your credentials each time, then go for it – this was just the simplest method for me (and it’s currently 11:05pm so I’m going to bed!)

Feel free to improve it, I’m sure there are plenty improvements that can be made, but it’s a starter for 10 for anyone out there just getting started with development in Azure SQL. Plus it’s kinda neat!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s