Returns a description of the context in which the request is executing
function execution_context(): string
string- - If the request was initiated via the proxygen, xbox, pagelet, fastcgi, or replay servers those values are returned. In client mode the string cli is returned, when executing in client mode on a server (via the unix socket interface) clisrv is returned. On the server with an unknown context the string "worker" is returned indicating the job was run on an unnamed JobQueue within the server.