I don’t think you’ll be able to know which process (API key, Oauth2 or IP address) was used to identify the application.
However the analytics could be used to know if the caller presents a x-gateway-apikey header (API key) or an authorization header (Oauth2, assuming there’s no call with basic Auth.)
You need to activate the logging of http headers in the “Log invocation” policy that’s in the “Traffic management” stage. You could do this in the built-in “Transaction logging” global policy.
Headers will be obfuscated for obvious confidentiality reasons, but you’ll still be able to know who presents what, and make assumptions regarding the process that’s eventually used to identify the application and authenticate the call.
#API-Management#API-Gateway#webMethods