How to create App Service from Container Registry with Firewall Rules


I am attempting to create a Container Registry that is protected by firewall rules where the list of IP Addresses are the on-premise IP addresses of my company. I push the image from my on premise server to the Container Registry. Next I create an App Service and set its image source to the Container Registry. But, because the Container Registry is limited to on-premise IP addresses, the terraform script for the app service fails because it cannot reach the Container Registry to pull the image.

How can I know the outbound ip addresses of the App Service in advance of its creation?

The issue below articulates the problem better. But short of that enhancement, looking for a workaround.