Este script PHP se inspiró en la necesidad de hacer lo mismo que la pregunta original donde los servidores en cuestión ejecutaban versiones diferentes de MariaDB. Como es PHP, debería funcionar en cualquier plataforma que admita PHP (versión 7.3 o superior).
<?php
ini_set('display_errors','1');
ini_set('display_startup_errors','1');
error_reporting(E_ALL);
//
// You will want to modify the 4 variables below for your environment
//
$dbuser = 'root'; // DB user with authority to SHOW GRANTS from mysql.user
$dbpassword = 'blahblah'; // password for the DB user
$useroutfile = '/temp/Users.sql'; // where to write the user file that may be imported on new server
$grantoutfile = '/temp/Grants.sql'; // where to write the grant file that may be imported on new server
$ignore_users = ['root','replication_user']; // array of users that should NOT be exported
//
// There really should not be any reason to modify anything below this comment
// but please do browse through it and understand what is being done
//
$dsn = 'mysql:host=localhost;charset=utf8mb4';
$opt = [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION ,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC ,
PDO::ATTR_EMULATE_PREPARES => true ,
];
try {
$ourdb = new PDO ($dsn,$dbuser,$dbpassword,$opt);
} catch (PDOException $e) {
error_log($e); // log the error so it may be looked at later if necessary
echo 'Could not connect to the SQL server';
exit;
} // end of the try/catch block
$notuser = implode(',',array_map('add_quotes',$ignore_users));
//
// We got connected to the database so now let's make sure we can open the
// output files for writing - note that using mode w will overwrite any
// existing files so we'll always start off cleanly
//
$userout = fopen($useroutfile,'w');
if ($userout === false) { // could not open the output file for writing for some reason
error_log('Could not open the output file for writing (' . $useroutfile . ')');
exit;
} // end of if we could not open the output file for writing
$grantout = fopen($grantoutfile,'w');
if ($grantout === false) { // could not open the output file for writing for some reason
error_log('Could not open the output file for writing (' . $grantout . ')');
exit;
} // end of if we could not open the output file for writing
$Query = $ourdb->query("
SELECT CONCAT('SHOW GRANTS FOR ''', user, '''@''', host, ''';') AS query
FROM mysql.user
WHERE user NOT IN(" . implode(',',array_map('add_quotes',$ignore_users)) . ")
");
$users = $Query->fetchAll(PDO::FETCH_COLUMN);
foreach ($users as $GrantQ) { // go through each of the users found
$UserQ = $ourdb->query("$GrantQ"); // retrieve the grants for a user
$grants = $UserQ->fetchAll(PDO::FETCH_COLUMN);
foreach ($grants as $grant) { // go through each of the grants found for this user
if (stripos($grant,'IDENTIFIED BY PASSWORD') === false) {
fwrite($grantout,$grant . ';' . PHP_EOL); // write the command to actually do the grant
} else {
fwrite($userout,$grant . ';' . PHP_EOL); // write the command to actually do the grant
}
} // end of foreach through the grants found
} // end of foreach through the queries to show the grants for each user
fwrite($userout ,'FLUSH PRIVILEGES;' . PHP_EOL); // make sure SQL knows about the new users and privileges
fwrite($grantout,'FLUSH PRIVILEGES;' . PHP_EOL); // make sure SQL knows about the new users and privileges
fclose($userout); // close our output file
fclose($grantout); // close our output file
echo 'The grants for ' . count($users) . ' users were written to ' . $useroutfile . PHP_EOL;
function add_quotes($str) {return sprintf("'%s'", $str);}