How to write a message to a log file?

[dmitrii_fediuk]

You can write a message to the var/log/debug.log file by the following code:

\Magento\Framework\App\ObjectManager::getInstance()
    ->get('Psr\Log\LoggerInterface')
        ->debug('message')
;

Magento 1 has much more shorter way to do it:

Mage::log('message');

Magento 2 has shorter ways too: many objects have already the _logger property, so you can call inside such objects:

$this->_logger->debug('message');

But it is not the universal solution, because not all objects have the _logger property.

[dmitrii_fediuk]

See also:

See also:

• How to log an exception?
• How does \Magento\Framework\Logger\Monolog::critical() work?
• How does \Magento\Framework\Logger\Monolog::addRecord() work?
• The exceptions are loggged into the var/log/exception.log file
• The non-exceptional messages are loggged into the var/log/system.log file
• The debug messages are logged into the var/log/debug.log file
• The default implementation of the \Psr\Log\LoggerInterface is \Magento\Framework\Logger\Monolog
• How to write a message to a log file?