Adventures with Cosmos: Get Primary Connection String with PowerShell

When it comes to deploying my infrastructure to Azure I prefer an imperative approach over a declarative approach so I starting to work a lot with Azure CLI and Azure PowerShell.

That being said, I am working on an Web App which will be deployed to an App Service in Azure.

When I deploy the App Service I would like to add an App Setting COSMOSDB_CONNECTIONSTRING with the value of the Cosmos DB Primary SQL Connection String.

I thought this would be pretty straight-forward BUT my lack of familiarity with PowerShell made what ended up a simple task a bit more challenging.

So sharing my learning experience with other developers and more likely my future self with a faulty memory.

Open Visual Studio Code, or whatever tool you use to work with PowerShell files.

Create a new PowerShell file.

At the top of your file Add the following code:

#Requires -Module Az.CosmosDB

This will install the Az.CosmosDB module if it is not currently installed.

Then add the call to get the connections strings from CosmosDB.

$cosmosDBConnectionStrings = Get-AzCosmosDBAccountKey -ResourceGroupName YOUR_RESOURCE_GROUP_NAME -Name YOUR_COSMOS_ACCOUNT_NAME -Type "ConnectionStrings"

If you were to run the Get-AzCosmosDBAccountKey from the command line, the output would look like:

The output object is a Hashtable.

This is where things started to derail for me, if I would have treated the Hashtable like I would in C#, I would have been done in a matter of minutes, but I didn’t.

Anyway, the code to get the Primary SQL Connection String is as follows:

$cosmosDBPrimarySQLConnectionString = $cosmosDBConnectionStrings["Primary SQL Connection String"]

That’s it!

Now I could assign my App Setting with this value.

Was just that simple.