Logic App Authentication to Azure App Service

Question

I am developing some workflows on Azure, and I need some help with setting up authentication. Here is what I am setting up:

1. There are 2 tenants involved - tenant1 and tenant2
2. I have a web API deployed to an App Service on a subscription tied to tenant1
3. I also have a logic app on the same subscription as the web API that wants to periodically call the above API end points automatically
4. Other than the logic apps, only users from tenant2 should be allowed to call the above web API end points directly

How do I use authentication using Azure AD to set this up correctly? I have tried enabling AAD authentication on the app service, and playing with managed identities to allow the logic app to access it, but logic app authentication is not working. I seem to have set things up correctly to allow the users from tenant2 to access the API though, so now I just need to get the logic apps to authenticate with it correctly. I am looking for an option that uses managed identities.

Answer 1

You can turn on the System-Assigned managed identity in Logic App and your Web API and then use a Logic App Action with settings of Authentication like below to call authenticated API endpoint using Logic App: