How to Export & Import Existing User (with its Privileges!)

Question

I have an existing MySQL instance (test), containing 2 databases and a few users each having different access privileges to each database.

I now need to duplicate one of

Answer 1

I tackled this with a small C# program. There is code here to generate a script or apply the grants directly from source to destination. If porting from a Windows -> *nix environment you may have to consider case sensitivity issues.

using System;
using MySql.Data.MySqlClient;
using System.Configuration;
using System.IO;
using System.Collections.Generic;

namespace GenerateUsersScript
{
    class Program
    {
        static void Main(string[] args)
        {
            List grantsQueries = new List();

            // Get A Show Grants query for each user
            using (MySqlConnection sourceConn = OpenConnection("sourceDatabase"))
            {
                using (MySqlDataReader usersReader = GetUsersReader(sourceConn))
                {
                    while (usersReader.Read())
                    {
                        grantsQueries.Add(String.Format("SHOW GRANTS FOR '{0}'@'{1}'", usersReader[0], usersReader[1]));
                    }
                }

                Console.WriteLine("Exporting Grants For {0} Users", grantsQueries.Count);

                using (StreamWriter writer = File.CreateText(@".\UserPermissions.Sql"))
                {
                    // Then Execute each in turn 
                    foreach (string grantsSql in grantsQueries)
                    {
                        WritePermissionsScript(sourceConn, grantsSql, writer);
                    }

                    //using (MySqlConnection destConn = OpenConnection("targetDatabase"))
                    //{
                    //    MySqlCommand command = destConn.CreateCommand();

                    //    foreach (string grantsSql in grantsQueries)
                    //    {
                    //        WritePermissionsDirect(sourceConn, grantsSql, command);
                    //    }
                    //}
                }
            }

            Console.WriteLine("Done - Press A Key to Continue");

            Console.ReadKey();
        }

        private static void WritePermissionsDirect(MySqlConnection sourceConn, string grantsSql, MySqlCommand writeCommand)
        {
            MySqlCommand cmd = new MySqlCommand(grantsSql, sourceConn);

            using (MySqlDataReader grantsReader = cmd.ExecuteReader())
            {
                while (grantsReader.Read())
                {
                    try
                    {
                        writeCommand.CommandText = grantsReader[0].ToString(); 

                        writeCommand.ExecuteNonQuery();
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine(grantsReader[0].ToString());

                        Console.WriteLine(ex.Message);
                    }
                }
            } 
        }

        private static void WritePermissionsScript(MySqlConnection conn, string grantsSql, StreamWriter writer)
        {
            MySqlCommand command = new MySqlCommand(grantsSql, conn);

            using (MySqlDataReader grantsReader = command.ExecuteReader())
            {
                while (grantsReader.Read())
                {
                    writer.WriteLine(grantsReader[0] + ";");
                }
            }

            writer.WriteLine();
        }

        private static MySqlDataReader GetUsersReader(MySqlConnection conn)
        {
            string queryString = String.Format("SELECT User, Host FROM USER");
            MySqlCommand command = new MySqlCommand(queryString, conn);
            MySqlDataReader reader = command.ExecuteReader();
            return reader;
        }

        private static MySqlConnection OpenConnection(string connName)
        {
            string connectionString = ConfigurationManager.ConnectionStrings[connName].ConnectionString;
            MySqlConnection connection = new MySqlConnection(connectionString);
            connection.Open();
            return connection; 

        }
    }
}

with an app.config containing ...