I'm surprised to realize that there is NO logger available for HHVM! So I made this very simple (yet sufficient) one.

Usage:

Option 1: You can define a class similar to \Log\MainLogger. Set up log file in the class. Then use it like this:

\Log\MainLogger::log(\Log\LogLevel::DEBUG, \HH\Lib\Str\format(
"web_controller=%s query_string=%s",
$responder,
    json_encode($query_string),
));

Option 2:

\$logger = new \Log\Logger('main');

\$logger->addHandler(new \Log\LogToFileHandler(
'/path/to/your/logging/file.log',
));

\$logger->log(\Log\LogLevel::WARNING, 'test log content');