Log file output anywhere in Magento 2
The correct and Magento-proper way to add a log file is to inject the \Psr\Log\LoggerInterface class into the constructor to call the logger object. However, this is not always practical, especially when you need a quick output. Here's a simpler way to temporarily output to a text log file from anywhere in Magento 2.
$writer = new \Zend\Log\Writer\Stream(BP . '/var/log/my.log'); $logger = new \Zend\Log\Logger(); $logger->addWriter($writer); // Individual line or string output $logger->info('Single variable or line output: ' . $stringValue); // Dump an array $logger->info('Array: ' . print_r($arrayValue, true));
That's it. This will output to var/log/my.log. Keep in mind that print_r() will most likely run out of memory when outputting against an object in Magento 2. Try to use ->getData() when possible.