I was wondering this, too, and I found these lines in MonologServiceProvider.
if ($bridge = class_exists('Symfony\Bridge\Monolog\Logger')) {
$app['monolog.handler.debug'] = function () use ($app) {
return new DebugHandler($app['monolog.level']);
};
}
The logging to the Web Profiler is enabled by the Symfony Monolog Bridge component. I added this to my composer.json
:
"symfony/monolog-bridge": "~2.3"
Now I see log entries in that panel of the web profiler. (It's probably a good idea to make sure the version of the monolog-bridge is in line with the versions of other Symfony components you've declared in your composer.json
.)