core-bundle/src/Resources/contao/library/Contao/Automator.php
public function rotateLogs()
	{
		@trigger_error('Using Automator::rotateLogs() has been deprecated and will no longer work in Contao 5.0. Use the logger service instead, which rotates its log files automatically.', E_USER_DEPRECATED);

		$rootDir = System::getContainer()->getParameter('kernel.project_dir');
		$arrFiles = preg_grep('/\.log$/', scan($rootDir . '/system/logs'));

		foreach ($arrFiles as $strFile)
		{
			$objFile = new File('system/logs/' . $strFile . '.9');

			// Delete the oldest file
			if ($objFile->exists())
			{
				$objFile->delete();
			}

			// Rotate the files (e.g. error.log.4 becomes error.log.5)
			for ($i=8; $i>0; $i--)
			{
				$strGzName = 'system/logs/' . $strFile . '.' . $i;

				if (file_exists($rootDir . '/' . $strGzName))
				{
					$objFile = new File($strGzName);
					$objFile->renameTo('system/logs/' . $strFile . '.' . ($i+1));
				}
			}

			// Add .1 to the latest file
			$objFile = new File('system/logs/' . $strFile);
			$objFile->renameTo('system/logs/' . $strFile . '.1');
		}
	}
public function rotateLogs()
	{
		@trigger_error('Using Automator::rotateLogs() has been deprecated and will no longer work in Contao 5.0. Use the logger service instead, which rotates its log files automatically.', E_USER_DEPRECATED);

		$rootDir = System::getContainer()->getParameter('kernel.project_dir');
		$arrFiles = preg_grep('/\.log$/', scan($rootDir . '/system/logs'));

		foreach ($arrFiles as $strFile)
		{
			$objFile = new File('system/logs/' . $strFile . '.9');

			// Delete the oldest file
			if ($objFile->exists())
			{
				$objFile->delete();
			}

			// Rotate the files (e.g. error.log.4 becomes error.log.5)
			for ($i=8; $i>0; $i--)
			{
				$strGzName = 'system/logs/' . $strFile . '.' . $i;

				if (file_exists($rootDir . '/' . $strGzName))
				{
					$objFile = new File($strGzName);
					$objFile->renameTo('system/logs/' . $strFile . '.' . ($i+1));
				}
			}

			// Add .1 to the latest file
			$objFile = new File('system/logs/' . $strFile);
			$objFile->renameTo('system/logs/' . $strFile . '.1');
		}
	}
Rotate the log files

@deprecated Deprecated since Contao 4.0, to be removed in Contao 5.0.
Use the logger service instead, which rotates its log files automatically.