Can you use a Managed Identity to access an Azure Function from an Azure App Service?

Question

I have created an Azure Function that is called by a single Azure Web App I also created. I want to secure the Azure Function to only allow the Azure Web App to call it. I know how to do it by creating an App Registration and passing ClientID and Secrets. But I was wondering if I can do it by using the Azure Web App's Service Identity. That way I do not need to maintain the ClientID and Secrets. Any advice would be appreciated. Thank you.

Answer 1

As noted in the comments, you can use MSI for this.

As an alternative approach you could also lock it down on the network layer by integrating the App Service into a VNET and lock down incoming traffic on the Function to that one subnet of the App Service.