Tech FAQs: September 2021

How Logging works in Apache & PHP

Apache and php maintain the logs in the error.log file which is the default file for logging.

File path to error.log is /var/log/apache2/error.log

PHP allows us to log into a different file using

ini_set(‘error_log’, ‘path/to/log/file.log’)

Following are different methods for logging available

Here's a PHP function to create period wise logs

<?php

class ErrorLog {

private $logFilePath;

/**

* ErrorLog constructor.

* @param string $logFilePath

public function __construct(string $logFilePath) {

$this->logFilePath = $logFilePath;

}

/**

* Parses the PHP error log to an array.

* @return \Generator

public function getParsedLogFile($sLogType = null, $dStartDate = null, $dEndDate = null): \Generator {

$parsedLogs = [];

$logFileHandle = fopen($this->logFilePath, 'rb');

while (!feof($logFileHandle)) {

$currentLine = str_replace(PHP_EOL, '', fgets($logFileHandle));

// Normal error log line starts with the date & time in []

if ('[' === $currentLine[0]) {

if (10000 === \count($parsedLogs)) {

yield $parsedLogs;

$parsedLogs = [];

}

// Get the datetime when the error occurred and convert it to berlin timezone

try {

$dateArr = [];

preg_match('~^\[(.*?)\]~', $currentLine, $dateArr);

$currentLine = str_replace($dateArr[0], '', $currentLine);

$currentLine = trim($currentLine);

$dErrorDateTime = new DateTime($dateArr[1]);

$dErrorDateTime->setTimezone(new DateTimeZone('Asia/Kolkata'));

$errorDateTime = $dErrorDateTime->format('Y-m-d H:i:s');

} catch (\Exception $e) {

$errorDateTime = '';

}

// Get the type of the error

if (false !== strpos($currentLine, 'PHP Warning')) {

$currentLine = str_replace('PHP Warning:', '', $currentLine);

$currentLine = trim($currentLine);

$errorType = 'WARNING';

} else if (false !== strpos($currentLine, 'PHP Notice')) {

$currentLine = str_replace('PHP Notice:', '', $currentLine);

$currentLine = trim($currentLine);

$errorType = 'NOTICE';

} else if (false !== strpos($currentLine, 'PHP Fatal error')) {

$currentLine = str_replace('PHP Fatal error:', '', $currentLine);

$currentLine = trim($currentLine);

$errorType = 'FATAL';

} else if (false !== strpos($currentLine, 'PHP Parse error')) {

$currentLine = str_replace('PHP Parse error:', '', $currentLine);

$currentLine = trim($currentLine);

$errorType = 'SYNTAX';

} else if (false !== strpos($currentLine, 'PHP Exception')) {

$currentLine = str_replace('PHP Exception:', '', $currentLine);

$currentLine = trim($currentLine);

$errorType = 'EXCEPTION';

} else {

$errorType = 'UNKNOWN';

}

if (false !== strpos($currentLine, ' on line ')) {

$errorLine = explode(' on line ', $currentLine);

$errorLine = trim($errorLine[1]);

$currentLine = str_replace(' on line ' . $errorLine, '', $currentLine);

} else {

$errorLine = substr($currentLine, strrpos($currentLine, ':') + 1);

$currentLine = str_replace(':' . $errorLine, '', $currentLine);

}

$errorFile = explode(' in /', $currentLine);

$errorFile = '/' . trim($errorFile[1]);

$currentLine = str_replace(' in ' . $errorFile, '', $currentLine);

// The message of the error

$errorMessage = trim($currentLine);

if ($sLogType != null && $sLogType != $errorType) {

continue;

}

echo "<pre>";

if ($dStartDate != null && $dStartDate > $dErrorDateTime) {

continue;

}

if ($dEndDate != null && $dEndDate < $dErrorDateTime) {

continue;

}

$parsedLogs[] = [

'dateTime' => $errorDateTime,

'type' => $errorType,

'file' => $errorFile,

'line' => (int)$errorLine,

'message' => $errorMessage,

'stackTrace' => []

];

} // Stack trace beginning line

else if ('Stack trace:' === $currentLine) {

$stackTraceLineNumber = 0;

while (!feof($logFileHandle)) {

$currentLine = str_replace(PHP_EOL, '', fgets($logFileHandle));

// If the current line is a stack trace line

if ('#' === $currentLine[0]) {

$parsedLogsLastKey = key($parsedLogs);

$currentLine = str_replace('#' . $stackTraceLineNumber, '', $currentLine);

$parsedLogs[$parsedLogsLastKey]['stackTrace'][] = trim($currentLine);

$stackTraceLineNumber++;

} // If the current line is the last stack trace ('thrown in...')

else {

break;

}

yield $parsedLogs;

}

$oErrorLog = new ErrorLog(ini_get('error_log'));

foreach ($oErrorLog->getParsedLogFile('SYNTAX',new DateTime('2021-04-25 12:15:30'), new DateTime('2021-04-25 16:00:05')

) as $key => $value) {

var_dump($value);

}

Ref: From Internal memo provided by Kaveri Bhumkar

Tech FAQs

Wednesday 29 September 2021

Logging in PHP

How Logging works in Apache & PHP

Here's a PHP function to create period wise logs

Check the amount of free disk space in Ubuntu