Azure App Service with User-assigned identity: retrieve clientId in the app?

Question

I am running an Azure App Service with one User-assigned identity (and no system-managed identity):

Is there a way inside the app (ie my custom code) to retrieve the clientId of the identity? Or do I need to set that in a app setting to be available inside the app?

Question comes from the fact that I want to use this identity to authenticate using an AzureCredential and it needs the clientId.

Or is the better way to use MSI and set the app setting AzureServicesAuthConnectionString ?

Answer 1

Looking at environment variables in an App Service with a User assigned Managed Identity, there is nothing that contains the id.

So you should set the id as an App Setting on the app, and use it. I definitely recommend that you use AzureCredential as it is the newer one. The older AzureServiceTokenProvider would not give you any advantage over it anyway.