LogServiceProvider.php

<?php
namespace Log;

use Common\Config;
use GMO\Cache\CacheKeys;
use GMO\Common\String;
use Log\Handler\LogstashHandler;
use Log\Processor\EnvProcessor;
use Log\Processor\RequestProcessor;
use Monolog\Handler\ChromePHPHandler;
use Monolog\Logger;
use Routing\RouterListener;
use Silex\Application;
use Silex\ServiceProviderInterface;

class LogServiceProvider implements ServiceProviderInterface
{
	public function register(Application $app) {

		$app['logger.redis'] = $app->share(function ($app) {
			/** @var \GMO\Cache\Redis $redis */
			$redis = $app[CacheKeys::REDIS_NEW];
			$redis->selectDb(4);
			return $redis;
		});

		$app['logger.handlers'] = $app->share(function ($app) {
			$handlers = [
				new LogstashHandler($app['logger.redis'], 'GL', 'gl_logging'),
			];

			if (PHP_SAPI !== 'cli' && Config::isDevelopment()) {
				$handlers[] = new ChromePHPHandler(Logger::DEBUG, false);
			}

			return $handlers;
		});

		$app['logger.processors'] = $app->share(function ($app) {
			return [
				new EnvProcessor(Config::getEnvironment()),
				new RequestProcessor($app['request_stack'])
			];
		});

		$app['logger.new'] = $app->protect(function ($name) use ($app) {
			$name = String::className($name) ?: $name;
			return new Logger($name, $app['logger.handlers'], $app['logger.processors']);
		});

		$app['logger'] = $app->share(function ($app) {
			return $app['logger.new']('App');
		});

		$app->register(new RouterListener());
	}

	public function boot(Application $app) {
		$app['dispatcher']->addSubscriber(new HttpLogListener($app['logger']));
	}
}

RequestProcessor.php

<?php
namespace Log\Processor;

use Symfony\Component\HttpFoundation\RequestStack;

class RequestProcessor
{
	protected $requestStack;

	public function __construct(RequestStack $requestStack) {
		$this->requestStack = $requestStack;
	}

	public function __invoke(array $record) {
		if (!$request = $this->requestStack->getCurrentRequest()) {
			return $record;
		}

		$params = [
			'method' => $request->getMethod(),
			'host' => $request->getHost(),
			'path' =>  $request->getPathInfo(),
			'query' => $request->query->all(),
		];
		if ($request->isMethod('POST')) {
			$params['body'] = $request->request->all();
		}

		$record['extra']['request'] = $params;
		return $record;
	}
}

So I end up calling $app['logger.new']('channelName') in lots of places.