WorkflowBundle/Command/LockWaitCommand.php

<?php

namespace WorkflowBundle\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class LockWaitCommand extends Command
{

    protected function configure()
    {
        $this
            ->setName('lock:wait')
            ->setDescription('Lock wait command')
            ->setHelp('Lock wait command. Wait for lock a file. The lock can be either exclusive or shared')
            ->addArgument(
                'filename',
                InputOption::VALUE_REQUIRED,
                'Filename'
            )
            ->addOption(
                'dir',
                null,
                InputOption::VALUE_REQUIRED,
                'Directory path file',
                '/tmp'    
            )
            ->addOption(
                'timeout',
                null,
                InputOption::VALUE_REQUIRED,
                'Timeout execution (ms)',
                600
            )
            ->addOption(
                'no-exclusive',
                'no-e',
                InputOption::VALUE_NONE,
                'No exclusive lock'
            )
        ;
    }

    /**
     * @param InputInterface $input
     * @param OutputInterface $output
     */
    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $filename = $input->getArgument('filename');
        $dir = $input->getOption('dir');
        $timeout = $input->getOption('timeout');
        $no_exclusive = $input->getOption('no-exclusive');
        if ($filename) {
            $handle = $this->fopen($filename, $dir);
            if ($this->flock($handle, $timeout, $no_exclusive)) {
                $output->writeln('<info>OK</info>');
            }
        } else {
            $output->writeln('<error>Enter a valid filename</error>');
        }
    }

    /**
     * @param string $filename
     * @param string $dir
     * 
     * @return resource
     */
    protected function fopen($filename, $dir)
    {
        // limpio el filename completo
        $invalid_chars = array(" ", '"', "'", "&", "\\", "?", "#", "$", "//");
        $delimiter = DIRECTORY_SEPARATOR;
        $dir_pieces = explode($delimiter, str_replace($invalid_chars, '', $dir));
        $filename_pieces = explode($delimiter, str_replace($invalid_chars, '', $filename));
        $last_filename_piece = array_pop($filename_pieces);
        
        $dir = $delimiter . implode($delimiter, array_filter(array_merge($dir_pieces, $filename_pieces)));
        $filename = $dir . $delimiter . $last_filename_piece;
        
        if (!file_exists($dir)) {
            mkdir($dir, 0777, true);
        }

        return fopen($filename, "w+");
    }
    
    /**
     * @param resource $handle
     * @param int $timeout
     * @param boolean $no_exclusive
     * 
     * @throws \Exception
     */
    protected function flock($handle, $timeout = 600, $no_exclusive = false)
    {
        pcntl_signal(SIGALRM, function() {
            exit(1);
        });
        pcntl_alarm($timeout);
        try {
            $operation = LOCK_EX;
            if ($no_exclusive) {
                $operation = LOCK_SH;
            }
            if (!flock($handle, $operation)) {
                throw new \Exception("Timeout");
            }
        } finally {
            pcntl_alarm(0);
            pcntl_signal_dispatch();
            pcntl_signal(SIGALRM, SIG_DFL);
        }

        flock($handle, LOCK_UN);
        fclose($handle);
        
        return true;
    }

}