Based on https://gist.github.com/tawfekov/4079388

create_entities_from_db.php

<?php

use Doctrine\ORM\Tools\DisconnectedClassMetadataFactory;

include './vendor/autoload.php';
$classLoader = new \Doctrine\Common\ClassLoader('Entities', __DIR__);
$classLoader->register();
$classLoader = new \Doctrine\Common\ClassLoader('Proxies', __DIR__);
$classLoader->register();
// config
$config = new \Doctrine\ORM\Configuration();
$config->setMetadataDriverImpl($config->newDefaultAnnotationDriver(__DIR__ . '/Entities'));
$config->setMetadataCacheImpl(new \Doctrine\Common\Cache\ArrayCache);
$config->setProxyDir(__DIR__ . '/Proxies');
$config->setProxyNamespace('Proxies');
$connectionParams = array(
    'driver' => 'pdo_mysql',
    'host' => 'localhost',
    'port' => '3306',
    'user' => 'root',
    'password' => 'root',
    'dbname' => 'dbname',
    'charset' => 'utf8',
);
$em = \Doctrine\ORM\EntityManager::create($connectionParams, $config);


// custom datatypes (not mapped for reverse engineering)
$em->getConnection()->getDatabasePlatform()->registerDoctrineTypeMapping('set', 'string');
$em->getConnection()->getDatabasePlatform()->registerDoctrineTypeMapping('enum', 'string');

// Register types
\Doctrine\DBAL\Types\Type::addType('xxx', \Namespace\Of\Doctrine\XXXType::class);


// fetch metadata
$driver = new \Doctrine\ORM\Mapping\Driver\DatabaseDriver(
    $em->getConnection()->getSchemaManager()
);
$em->getConfiguration()->setMetadataDriverImpl($driver);
$cmf = new DisconnectedClassMetadataFactory();
$cmf->setEntityManager($em);
$classes = $driver->getAllClassNames();
$metadata = $cmf->getAllMetadata();
$generator = new Doctrine\ORM\Tools\EntityGenerator();
$generator->setUpdateEntityIfExists(true);
$generator->setGenerateStubMethods(true);
$generator->setGenerateAnnotations(true);
$generator->generate($metadata, __DIR__ . '/Entities');
print 'Done!';