LOGGING
The App Engine web server captures everything the handler script writes to the standard output stream for the response to the web request. It also captures everything the handler script writes to the standard error stream, and stores it as log data. Log data for your application can be viewed and analyzed using the Administration Console, or downloaded using appcfg.py request_logs.
The App Engine PHP runtime environment includes support for logging arbitrary messages from your application using PHP's built-in
syslog() function, which invokes the Logs PHP Api.if (authorized_user()) {
// Some code
} else {
syslog(LOG_WARNING, 'Unauthorized access');
}