In some cases it would be very helpful to have access to the Principal when executing a function.
It may seem obvious that if one has a reference to the cache that you could get to the SecurityManager and extract the Subject and thus the Principal from there. However, in some cases, Geode will seamlessly proxy a function call from one server to the other. This will typically happen with onRegion calls and partitioned regions. In such cases, the security context is lost and thus the principal is not accessible.