Symfony ConsoleEvents: Create a Listener that add a "--time" global option to all commands and print the start/end time

CommandTimeOptionEventListener.php

<?php

//app.console_event_listener:
//      class: AppBundle\Listener\CommandTimeOptionEventListener
//      tags:
//          - { name: kernel.event_listener, event: console.command, method: onConsoleCommand }
//          - { name: kernel.event_listener, event: console.terminate, method: onConsoleTerminate }

namespace AppBundle\Listener;

use Symfony\Component\Console\Event\ConsoleCommandEvent;
use Symfony\Component\Console\Event\ConsoleTerminateEvent;
use Symfony\Component\Console\Input\ArgvInput;
use Symfony\Component\Console\Input\InputOption;

class CommandTimeOptionEventListener
{
    /** @var  boolean */
    private $optionTime;

    /**
     * @param ConsoleCommandEvent $event
     */
    public function onConsoleCommand(ConsoleCommandEvent $event)
    {
        $inputDefinition = $event->getCommand()->getApplication()->getDefinition();
        $message = 'To display in stdout the start and finish time take for the command';
        $inputDefinition->addOption(new InputOption('time', null, InputOption::VALUE_NONE, $message));

        $event->getCommand()->mergeApplicationDefinition(true);

        $input = $event->getInput();

        $input->bind($event->getCommand()->getDefinition());

        if ($this->optionTime = $input->getOption('time')) {
            $name = $event->getCommand()->getName();
            $event->getOutput()->writeln(
                sprintf('<info>[Command: %s] started at: %s</info>', $name, $this->displayTime())
            );
        }
    }

    /**
     * @param ConsoleTerminateEvent $event
     */
    public function onConsoleTerminate(ConsoleTerminateEvent $event)
    {
        if ($this->optionTime) {
            $name = $event->getCommand()->getName();
            $event->getOutput()->writeln(
                sprintf('<info>[Command: %s] finished at: %s</info>', $name, $this->displayTime())
            );
        }
    }

    /**
     * @return string
     */
    private function displayTime()
    {
        return \DateTime::createFromFormat('U.u', microtime(true))->format("Y-m-d H:i:s.u");
    }
}