MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object

[det-iot]

Hello,

I have a task with a parallel.ForEach ( I have also tried with a simple foreach)

Parallel.ForEach(receiveMessageResponse.Messages, message =>
{
    if (!string.IsNullOrEmpty(message.Body))
    {
        try
        {
            mqtt.ManageMQTTClient(MQTTconfigPublisher, message.Body).GetAwaiter().GetResult();
        }
        catch (Exception e)
        {
            parallelExceptions.Enqueue(e);
        }
    }
});

And when I run the app I have the following error:

MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object
Object name: 'System.Net.Sockets.Socket'. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
at AmpliaControlSystem.MQTT.ManageMQTTClient(MQTTConfiguration MQTTconfigPublisher, String payload) in /app/MQTT.cs:line 38

As a note, this happened to me in local, but I re-write the code from the beggining and it was fixed. Now I'm trying to deploy to AWS and the error happen again

The task ManageMQTTClient which produce the error:

public async Task ManageMQTTClient( MQTTConfiguration MQTTconfigPublisher, string payload)
{
    string topic = payload.Split(";")[1];
    string cliente =  Guid.NewGuid().ToString();
    try
    {
        IMqttClientOptions optionsPublisher = new MqttClientOptionsBuilder()
                    .WithTcpServer(MQTTconfigPublisher.Servidor)
                    .WithClientId(cliente)
                    .WithCredentials(MQTTconfigPublisher.Username, MQTTconfigPublisher.Password)
                    .WithCleanSession(false)
                    .WithKeepAlivePeriod(System.TimeSpan.FromSeconds(60))
                    .Build();

        IMqttClient mqttClientPublisher = new MqttFactory().CreateMqttClient();


        await mqttClientPublisher.ConnectAsync(optionsPublisher);

        if (mqttClientPublisher.IsConnected)
        {
            try
            {
                await mqttClientPublisher.PublishAsync(topic, payload.Split(";")[2], MQTTnet.Protocol.MqttQualityOfServiceLevel.ExactlyOnce);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error en 1" + ex);
                throw;
            }
        }
        //await mqttClientPublisher.DisconnectAsync();
    }
    catch (Exception ex)
    {
        Console.WriteLine("Error en 2" + ex);
        throw;
    }
}

The line 38 in the original code (here I have deleted the comments) is:

await mqttClientPublisher.ConnectAsync(optionsPublisher);

I'm using NuGet MQTTnet 3.0.5 and Net Core 2.1

Which project is your bug related to?

• Client

[SeppPenner]

For me, this seems quite similar to https://github.com/chkr1011/MQTTnet/issues/728 (But it's not a duplicate).

[det-iot]

Finally, I got what was wrong.

I was trying to access lo local broker (local ip) from the outside.

The problem here was the exception messages didn't say anything about the connection was no able to be establish.

Should the error message say something about that?

[SeppPenner]

Should the error message say something about that?

If you ask me, yes. I'm not in the implementation details (yet), so @chkr1011 needs to answer this as well.

[erikkj]

I have a similar issue in my code. I am using ManagedClient with reconnect delay = 10 seconds. Sporadic in my logs i see exceptions like this when the client disconnects:

2019-08-20 17:06:47.753 +00:00 [ERR] >> [2019-08-20T17:06:47.7478776Z] [187] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)

The client is able to reconnect to the server most of the times, but sometimes the client "dies" and does not run anymore. The last log message from MQTTClient in my log when this happens is this:

2019-08-20 17:06:27.736 +00:00 [ERR] >> [2019-08-20T17:06:27.7217443Z] [174] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Connection refused []:8883 ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: Connection refused []:8883
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
   at System.Net.Sockets.Socket.MultipleAddressConnectCallback(IAsyncResult result)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
2019-08-20 17:06:33.405 +00:00 [DBG] Starting HttpMessageHandler cleanup cycle with 1 items
2019-08-20 17:06:33.407 +00:00 [DBG] Ending HttpMessageHandler cleanup cycle after 0.0099ms - processed: 0 items - remaining: 1 items
2019-08-20 17:06:37.734 +00:00 [DBG] >> [2019-08-20T17:06:37.7338579Z] [123] [MqttClient] [Verbose]: Trying to connect with server 'URL' (Timeout=00:00:10).
2019-08-20 17:06:43.404 +00:00 [DBG] Starting HttpMessageHandler cleanup cycle with 1 items
2019-08-20 17:06:43.411 +00:00 [DBG] Ending HttpMessageHandler cleanup cycle after 0.0099ms - processed: 0 items - remaining: 1 items
2019-08-20 17:06:47.753 +00:00 [ERR] >> [2019-08-20T17:06:47.7478776Z] [187] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
2019-08-20 17:06:47.755 +00:00 [DBG] >> [2019-08-20T17:06:47.7552332Z] [187] [MqttClient] [Verbose]: Disconnecting [Timeout=00:00:10]

[xxGL1TCHxx]

I have a similar issue in my code. I am using ManagedClient with reconnect delay = 10 seconds. Sporadic in my logs i see exceptions like this when the client disconnects:

2019-08-20 17:06:47.753 +00:00 [ERR] >> [2019-08-20T17:06:47.7478776Z] [187] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)

The client is able to reconnect to the server most of the times, but sometimes the client "dies" and does not run anymore. The last log message from MQTTClient in my log when this happens is this:

2019-08-20 17:06:27.736 +00:00 [ERR] >> [2019-08-20T17:06:27.7217443Z] [174] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Connection refused []:8883 ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: Connection refused []:8883
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
   at System.Net.Sockets.Socket.MultipleAddressConnectCallback(IAsyncResult result)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
2019-08-20 17:06:33.405 +00:00 [DBG] Starting HttpMessageHandler cleanup cycle with 1 items
2019-08-20 17:06:33.407 +00:00 [DBG] Ending HttpMessageHandler cleanup cycle after 0.0099ms - processed: 0 items - remaining: 1 items
2019-08-20 17:06:37.734 +00:00 [DBG] >> [2019-08-20T17:06:37.7338579Z] [123] [MqttClient] [Verbose]: Trying to connect with server 'URL' (Timeout=00:00:10).
2019-08-20 17:06:43.404 +00:00 [DBG] Starting HttpMessageHandler cleanup cycle with 1 items
2019-08-20 17:06:43.411 +00:00 [DBG] Ending HttpMessageHandler cleanup cycle after 0.0099ms - processed: 0 items - remaining: 1 items
2019-08-20 17:06:47.753 +00:00 [ERR] >> [2019-08-20T17:06:47.7478776Z] [187] [MqttClient] [Error]: Error while connecting with server.
MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'. ---> System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__274_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at MQTTnet.Implementations.MqttTcpChannel.ConnectAsync(CancellationToken cancellationToken)
   at MQTTnet.Internal.MqttTaskTimeout.WaitAsync(Func`2 action, TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
   at MQTTnet.Adapter.MqttChannelAdapter.ConnectAsync(TimeSpan timeout, CancellationToken cancellationToken)
   at MQTTnet.Client.MqttClient.ConnectAsync(IMqttClientOptions options, CancellationToken cancellationToken)
2019-08-20 17:06:47.755 +00:00 [DBG] >> [2019-08-20T17:06:47.7552332Z] [187] [MqttClient] [Verbose]: Disconnecting [Timeout=00:00:10]

FWIW, I'm having the same exact issue as Erikkj. I have had several instances over the past few weeks where the client throws this exception and continues to fail to reconnect. Restarting the application clears it up. Sorry if this is a separate issue, I just ran across it while trying to Google my problem.

[stedaho]

I can confirm that this issue occurs occasionally on my test system, too. For the case it helps: I noticed that I never see a "OnDisconnected" event before the re-connecting fails.

_MQTTnet v3.0.8, .NET Core 3.0, Linux on ARM32._

[alexey-grebennikov]

I have the same issue.
_MQTTnet v3.0.8, .NET Core 2.1, Windows Server_

[ps-weber]

I have a similar issue where I get a ObjectDisposedExcpetion wrapped in a MqttCommunicationException when the connection to the server times out while running MqttClient.ConnectAsync(). I traced it back to this snippet in MqttTcpCannel.cs:

// Workaround for: workaround for https://github.com/dotnet/corefx/issues/24430
using (cancellationToken.Register(() => socket.Dispose()))
{
#if NET452 || NET461
    await Task.Factory.FromAsync(socket.BeginConnect, socket.EndConnect, _options.Server, _options.GetPort(), null).ConfigureAwait(false);
#else
    await socket.ConnectAsync(_options.Server, _options.GetPort()).ConfigureAwait(false);
#endif
}

I would suggest catching the ObjectDisposedExcpetion and hiding the workaround to library users, since ObjectDisposedExcpetion sounds like an implementation error rather than a simple timeout.

[Feyb]

also getting this even with the new MQTTnet 3.0.9-rc1, but its usually in a combination with a timeout. It does reconnect then i get like 2-3 messages, the same happens again and so on until the client dies.

> 2019-12-17 02:33:21.026 +00:00    [wrn]   Timeout while waiting for packet of type 'MqttPingRespPacket'.  [MQTTnet.MqttClient]
> 2019-12-17 02:33:21.031 +00:00    [wrn]   Communication error while sending/receiving keep alive packets. [MQTTnet.MqttClient]
> MQTTnet.Exceptions.MqttCommunicationTimedOutException: Exception of type 'MQTTnet.Exceptions.MqttCommunicationTimedOutException' was thrown.
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.PacketDispatcher.MqttPacketAwaiter`1.<WaitOneAsync>d__4.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Client.MqttClient.<SendAndReceiveAsync>d__46`1.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Client.MqttClient.<TrySendKeepAliveMessagesAsync>d__47.MoveNext()
> 2019-12-17 02:33:21.423 +00:00    [wrn]   Disconnected    [.....Services.MqttClient]
> 2019-12-17 02:33:21.426 +00:00    [wrn]   Communication error while receiving packets.    [MQTTnet.MqttClient]
> MQTTnet.Exceptions.MqttCommunicationException: Cannot access a disposed object.
> Object name: 'System.Net.Sockets.NetworkStream'. ---> System.ObjectDisposedException: Cannot access a disposed object.
> Object name: 'System.Net.Sockets.NetworkStream'.
>    at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
>    at System.IO.Stream.<>c.<BeginEndReadAsync>b__43_1(Stream stream, IAsyncResult asyncResult)
>    at System.Threading.Tasks.TaskFactory`1.FromAsyncTrimPromise`1.Complete(TInstance thisRef, Func`3 endMethod, IAsyncResult asyncResult, Boolean requiresSynchronization)
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Implementations.MqttTcpChannel.<ReadAsync>d__17.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Formatter.MqttPacketReader.<ReadFixedHeaderAsync>d__3.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Adapter.MqttChannelAdapter.<ReceiveAsync>d__37.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Adapter.MqttChannelAdapter.<ReceivePacketAsync>d__35.MoveNext()
>    --- End of inner exception stack trace ---
>    at MQTTnet.Adapter.MqttChannelAdapter.WrapException(Exception exception)
>    at MQTTnet.Adapter.MqttChannelAdapter.<ReceivePacketAsync>d__35.MoveNext()
> --- End of stack trace from previous location where exception was thrown ---
>    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
>    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
>    at MQTTnet.Client.MqttClient.<TryReceivePacketsAsync>d__48.MoveNext()
> 2019-12-17 02:33:21.427 +00:00    [wrn]   Disconnected    [.....Services.MqttClient]

[andrei-m-code]

@Feyb @JanEggers confirmed. we're getting same object disposed exception with 3.0.9-rc1`. Thoughts?

.NET Core 3.0, Windows 10

[JanEggers]

@andrei-m-code I dont know if @chkr1011 created a new version that contains the fixes I did last year?

@chkr1011 can you please verify / do so?