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