Magento 2 Custom Logger - 2nd Approach

Data.php

<?php

// File: app/code/MagePsycho/Helper/Data.php
// Usage: MagePsycho\Demo\Helper\Data::log($message)

namespace MagePsycho\Demo\Helper;

class Data extends \Magento\Framework\App\Helper\AbstractHelper
{
	/**
	 * @var \Psr\Log\LoggerInterface
	 */
	protected $_logger;

	/**
	 * @param \Magento\Framework\App\Helper\Context $context
	 * @param \MagePsycho\Demo\Logger\Logger $logger
	 */
	public function __construct(
		\Magento\Framework\App\Helper\Context $context,
		\MagePsycho\Demo\Logger\Logger $logger
	) {
		$this->_logger                  = $logger;

		parent::__construct($context);
	}

	/**
	 *
	 * @param $message
	 */
	public function log($message)
	{
			$this->_logger->debug($message);
	}

}

di.xml

<?xml version="1.0"?>

<!-- File: app/code/MagePsycho/Demo/etc/di.xml -->

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">

    <virtualType name="customLogger" type="Magento\Framework\Logger\Monolog">
        <arguments>
            <argument name="handlers"  xsi:type="array">
                <item name="debug" xsi:type="object">MagePsycho\Demo\Logger\Handler</item>
            </argument>
        </arguments>
    </virtualType>

</config>

Handler.php

<?php

//File: app/code/MagePsycho/Demo/Logger/Handler.php

namespace MagePsycho\Demo\Logger;

use Magento\Framework\Logger\Handler\Base;
use Monolog\Logger;

class Handler extends Base
{
	/**
	 * Logging level
	 * @var int
	 */
	protected $loggerType = Logger::DEBUG;

	/**
	 * File name
	 * @var string
	 */
	protected $fileName = '/var/log/magepsycho_demo.log';
}