Wait for is useful for docker images

WaitForCommand.php

<?php
namespace App\Command;

use Symfony\Bundle\FrameworkBundle\Command\ContainerAwareCommand;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Output\OutputInterface;
use App\Service\CacheService;

class WaitForCommand extends ContainerAwareCommand
{
    protected function configure()
    {
        $this
            ->setName('tools:wait-for')
            ->setDescription('Waits dependent services, db, redis, elastic-search ...')
            ->setHelp('This command allows you to create a user...')
            ->addArgument('thing', InputArgument::OPTIONAL, 'what to wait for [db, redis, getslug]');
    }

    private function waitForDatabase(OutputInterface $output)
    {
        sleep(3);
        try {
            $entityManager = $this->getContainer()->get('doctrine');
            $output->writeln('ping connection');
            $ping = $entityManager->getConnection()->ping();
            if ($ping) {
                $output->writeln('db ping ready 🚀');
                return;
            }
            $output->writeln('Waiting for database connection');
            $this->waitForDatabase($output);
            return;
        } catch (\Exception $e) {
            if (strpos($e->getMessage(), 'database "azp" does not exist') !== false) {
                $output->writeln('db missing, so ready to go 🚀');
                return;
            }
            $output->writeln('>>> ' . $e->getMessage());
            $this->waitForDatabase($output);
            return;
        }
    }

    private function waitForGetSlug(OutputInterface $output)
    {
        $entityManager = $this->getContainer()->get('doctrine');
        $queryExtension = 'CREATE EXTENSION IF NOT EXISTS "uuid-ossp";';
        $statement = $entityManager->getConnection()->prepare($queryExtension);
        $statement->execute();
        return;
    }

    private function waitForRedis(OutputInterface $output)
    {
        try {
            $cacheService = $this->getContainer()->get('app.cache');
            $cache = $cacheService->getInstance();
            $item = $cache->getItem('wait-for-redis');
            $item->set(true);
            $cache->save($item);

            if ($item->isHit()) {
                $output->writeln('Redis service is ready 🚀');
                return true;
            }

            $output->writeln('waiting for redis to start ...');
            sleep(1);
            $this->waitForRedis($output);
            return;
        } catch (\Exception $e) {
            $output->writeln('Waiting for redis ...');
            sleep(1);
            $this->waitForRedis($output);
        }
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $argument = $input->getArgument('thing');
        if ($argument === 'db') {
            $this->waitForDatabase($output);
        } elseif ($argument === 'db') {
            $this->waitForRedis($output);
        } elseif ($argument === 'getslug') {
            $this->waitForGetSlug($output);
        }
    }
}