Detect if mysql container is ready

entrypoint.sh

#!/bin/bash

php "./bin/mysql-is-ready"
php app/console doctrine:schema:create --no-debug
php app/console doctrine:schema:update --no-debug

is-mysql-ready.php

<?php

    while ( !$link ) {
        $link = mysqli_connect($_ENV["STREAX_BACKEND_DATABASE_HOST"],
                       $_ENV["STREAX_BACKEND_DATABASE_USER"],
                       $_ENV["STREAX_BACKEND_DATABASE_PASSWORD"],
                       $_ENV["STREAX_BACKEND_DATABASE_NAME"]);

        if (!$link) {
          echo "Error: Unable to connect to MySQL" . PHP_EOL;
          echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
          echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
          sleep(1);
        }
    }

    echo "Success: a proper connection to MySQL was made" . PHP_EOL;
    echo "Host information: " . mysqli_get_host_info($link) . PHP_EOL;

    mysqli_close($link);