PDO无法找到驱动程序Google App引擎

google app engine website clearly states that this feature is already available to use, but when I try using it, I get this error. Any ideas?

error message: could not find driver

php file for reference

<?php
$dbhost = 'localhost:8080';
$dbname = '*********'; #edited out
$dbuser = '****'; #edited out
$dbpass = '******'; #edited out

phpinfo(INFO_MODULES);

try{
$dbh = new pdo('mysql:host='.$dbhost.';dbname='.$dbname, $dbuser, $dbpass);

echo 'safe1';

foreach($dbh->query('SELECT * FROM eastInfo') as $row){
print_r($row);
}#end for
$dbh = null;
}catch(PDOException $e){
print "error!: ".$e->getMessage()."<br />";
die();
}#end try catch
?>

I am using Ubuntu Linux

try to use

mysql:unix_socket=/cloudsql/your-project-id:your-instance-name;dbname=your-db-name

instead for appengine and leave the password blank as it's not needed for local connections from user root.

Greets