`UsePeriodicPasswordProvider` causes intermittent access denied errors

[andreas-antoniou-cko]

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Software versions MySqlConnector version: 2.3.5 Server type (MySQL, MariaDB, Aurora, etc.) and version: MySQL .NET version: net6.0 (Optional) ORM NuGet packages and versions: n/a

Describe the bug We have an app that connects to a Aurora MySQL on AWS. We recently switched from using a fixed password to IAM authentication. After we realized we hit this issue we are testing a version using UsePeriodicPasswordProvider. The solution is working (connecting fine to the DB and no memory utilisation increase) but we do periodically get a spike of errors accessing the database with the following error: Access denied for user 'db_user'@'redacted ip address' (using password: YES)

Exception

MySqlConnector.MySqlException (0x80004005): Access denied for user 'db_user'@'redacted ip' (using password: YES)
   at MySqlConnector.Core.ServerSession.ReceiveReplyAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ServerSession.cs:line 897
   at MySqlConnector.Core.ServerSession.SwitchAuthenticationAsync(ConnectionSettings cs, String password, PayloadData payload, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ServerSession.cs:line 733
   at MySqlConnector.Core.ServerSession.ConnectAsync(ConnectionSettings cs, MySqlConnection connection, Int64 startingTimestamp, ILoadBalancer loadBalancer, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ServerSession.cs:line 537
   at MySqlConnector.Core.ConnectionPool.ConnectSessionAsync(MySqlConnection connection, Action`4 logMessage, Int64 startingTimestamp, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ConnectionPool.cs:line 493
   at MySqlConnector.Core.ConnectionPool.ConnectSessionAsync(MySqlConnection connection, Action`4 logMessage, Int64 startingTimestamp, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ConnectionPool.cs:line 493
   at MySqlConnector.Core.ConnectionPool.GetSessionAsync(MySqlConnection connection, Int64 startingTimestamp, Int32 timeoutMilliseconds, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ConnectionPool.cs:line 146
   at MySqlConnector.Core.ConnectionPool.GetSessionAsync(MySqlConnection connection, Int64 startingTimestamp, Int32 timeoutMilliseconds, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/ConnectionPool.cs:line 146
   at MySqlConnector.MySqlConnection.CreateSessionAsync(ConnectionPool pool, Int64 startingTimestamp, Activity activity, Nullable`1 ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlConnection.cs:line 964
   at MySqlConnector.MySqlConnection.OpenAsync(Nullable`1 ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlConnection.cs:line 453
   at StackExchange.Profiling.Data.ProfiledDbConnection.OpenAsync(CancellationToken cancellationToken) in C:\projects\dotnet\src\MiniProfiler.Shared\Data\ProfiledDbConnection.cs:line 142
   at Dapper.SqlMapper.MultiMapAsync[TFirst,TSecond,TThird,TFourth,TFifth,TSixth,TSeventh,TReturn](IDbConnection cnn, CommandDefinition command, Delegate map, String splitOn) in C:\projects\dapper\Dapper\SqlMapper.Async.cs:line 956
...redacted application code

Code sample The following snippet is used to setup the MySqlDataSourceBuilder instance:

var dataSourceBuilder = new MySqlDataSourceBuilder(GetToken());

_mySqlDataSource = dataSourceBuilder.UsePeriodicPasswordProvider(
                (_, __) => new ValueTask<string>(GetConnectionStringWithToken()),
                TimeSpan.FromMinutes(10), 
                TimeSpan.FromSeconds(10));

and then when creating a connection:

_mySqlDataSource.CreateConnection()

/* A concise code sample to reproduce the bug */

Expected behavior No access denied errors to occur.

Additional context Rolling back to the version where we update the connection string every 10min we do not observe these errors so I do not think this is an issue from an infrastructure perspective.