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Only one usage of each socket address (protocol/network address/port) is normally permitted when AppPool is recycled

I have a .net Core application hosted on IIS.
The application initializes WebSocketServer, by adding a wrapper class as a HostedService.
The hosted service execute the Start() method seen below on its StartAsync() and the Destroy() method on its StopAsync() method.
The problem that whenever the related application pool is recycled - the error in the title appears ("Only one usage of each socket address (protocol/network address/port) is normally permitted"). It happens because there is a new working process that starts-up and trying to use the ports of the socket before there is a shutdown of the current Working process which still use the socket with the same ports.
I'm trying to find a way of avoiding that situation, programmatically or by configuration.
Here is my code of the HostedService:
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using System;
using System.Diagnostics;
using System.Linq;
using System.Net.WebSockets;
using WebSocketSharp.Server;
namespace XXXX
{
public class WebsocketServerWrapper
{
// Thats an websocket server , he will host our service as web socket service.
private static WebSocketServer wss;
private static readonly object LockObject = new object();
public static IConfiguration Config { get; set; }
public static bool IsCreated()
{
return wss != null;
}
public static bool HasChannels()
{
if(IsCreated())
{
return wss.WebSocketServices.Paths.Any();
}
return false;
}
public static bool IsListening()
{
if (wss != null)
{
return wss.IsListening;
}
return false;
}
public static void AddChannel(string channel)
{
if (wss.WebSocketServices.Paths.Any((path) => path == channel) == false)
{
wss.AddWebSocketService(channel,() => new <class that treats the socket behaviour itself>(Config));
}
}
public static bool Start()
{
wss.Start();
if (IsListening())
{
return true;
}
else
{
return false;
}
}
public static bool Destroy()
{
var isDestroyed = false;
if(IsCreated())
{
removeWebSocketServices();
wss.Stop();
wss = null;
isDestroyed = true;
}
return isDestroyed;
}
internal static void removeWebSocketServices()
{
var channels = wss?.WebSocketServices?.Paths?.ToList() ?? null;
if (channels != null)
{
channels.ForEach(channel => { wss.RemoveWebSocketService(channel); channel = null; });
}
}
public static bool CreateWSSServer()
{
bool isCreationSucceeded = false;
if(!IsCreated())
{
lock(LockObject)
{
try
{
var wssUrl = Config.GetValue<string>(<WebsocketServerUrl adress>);
wss = new WebSocketServer($"ws://{wssUrl}");
isCreationSucceeded = true;
}
catch (WebSocketException wse)
{
Debug.WriteLine(wse);
return isCreationSucceeded;
}
catch (Exception e)
{
Debug.WriteLine(e);
return isCreationSucceeded;
}
}
}
isCreationSucceeded = true;
return isCreationSucceeded;
}
}
}

I found a solution to that scenario (edited it in the question) - it turns out that the scenario of the server starts-up with new worker process before the "old" worker process shutdown is not rare - there is a parameter in the application pool under Recycling => Disable Overlapped Recycle - if it set to true (it is false by default), then the startup with new Working process will occur only after the current worker process will shut-down

How can i successfully stop a service using c#?

I am trying to stop a service using the following code:
public static void StopService(string name, out string message)
{
message = string.Empty;
EndTask();
ServiceController sc = new ServiceController();
sc.ServiceName = name;
if (sc.Status == ServiceControllerStatus.Running)
{
try
{
sc.Stop();
sc.WaitForStatus(ServiceControllerStatus.Stopped);
}
catch (Exception e)
{
throw ex;
}
}
else
{
message = $"The service has been stopped.";
}
}
The EndTask() is defined as follows:
public static void EndTask()
{
string taskname = "myservice.exe";
string processName = taskname.Replace(".exe", "");
foreach (Process process in Process.GetProcessesByName(processName))
{
process.Kill();
}
}
But I occasionally get the following error
Cannot stop mytestservice service on computer '.'.Inner Exception: System.ComponentModel.Win32Exception
(0x80004005): The pipe has been ended"
Is this to do with the EndTask routine ? do i need to run the EndTask() asynchronously ?

UWP AppServiceConnection - SendResponseAsync returns AppServiceResponseStatus.Failure

I'm trying to create a UWP service app on the Raspberry Pi3 which provides the access to the on board UART. I'm facing an issue about the AppConnection Request/response.
this is the service method that handles the incoming requests from client apps
internal class Inbound
{
public static async void OnRequestReceived(AppServiceConnection sender, AppServiceRequestReceivedEventArgs args)
{
var messageDeferral = args.GetDeferral();
var response = new ValueSet();
bool success = false;
var msg = args.Request.Message.Keys;
if (args.Request.Message.TryGetValue(ServiceApiRequests.Keys.Command, out object command))
{
try
{
switch (command)
{
case ServiceApiRequests.CommandValues.UartWrite:
if (args.Request.Message.TryGetValue(ServiceApiRequests.Keys.UartTxBuffer, out object txBuffer))
{
string rxBuff = "";
success = await Pi3.Peripherals.Uart.GerInstance(57600).Write((string)txBuffer);
if (success)
{
Debug.WriteLine("Tx: " + (string)txBuffer);
if (args.Request.Message.TryGetValue(ServiceApiRequests.Keys.ReadUartResponse, out object getResponse))
{
if ((string)getResponse == ServiceApiRequests.ReadUartResponse.Yes)
{
rxBuff = await Pi3.Peripherals.Uart.GerInstance(57600).Read();
Debug.WriteLine("Rx: " + rxBuff);
}
}
}
response.Add(ServiceApiRequests.Keys.UartRxBuffer, rxBuff);
}
break;
}
}
catch (Exception ex)
{
success = false;
}
}
response.Add(new KeyValuePair<string, object>(ServiceApiRequests.Keys.Result, success ? ServiceApiRequests.ResultValues.Ok : ServiceApiRequests.ResultValues.Ko));
var result = await args.Request.SendResponseAsync(response);
if (result == AppServiceResponseStatus.Failure)
{
Debug.WriteLine("Failed to send the response");
}
messageDeferral.Complete();
}
}
As you can figure out, the Uart class is get using the Singleton pattern using the method Pi3.Peripherals.Uart.GerInstance(57600).
Following the code i using for send the request from the client app.
public static class Uart
{
public static IAsyncOperation<string> SendCommand(this AppServiceConnection DriverControllerConnection, string txBuffer, string awaitResponse = ServiceApiRequests.ReadUartResponse.Yes)
{
return _SendCommand(DriverControllerConnection, txBuffer, awaitResponse).AsAsyncOperation();
}
private static async Task<string> _SendCommand(AppServiceConnection DriverControllerConnection, string txBuffer, string awaitResponse)
{
AppServiceResponse response = null;
string response_str = "";
try
{
if (DriverControllerConnection != null)
{
response = await DriverControllerConnection.SendMessageAsync(new ServiceApiRequests.UartWrite().GetCommand(txBuffer, awaitResponse));
if (response.Status == AppServiceResponseStatus.Success)
{
if (response.Message.TryGetValue(ServiceApiRequests.Keys.Result, out object result))
{
if ((string)result == ServiceApiRequests.ResultValues.Ok && awaitResponse == ServiceApiRequests.ReadUartResponse.Yes)
{
response_str = response.Message[ServiceApiRequests.Keys.UartRxBuffer] as string;
}
}
}
}
}
catch (Exception ex)
{
// TODO: log
}
return response_str;
}
}
The system works well just for a while, until i have response.Status == AppServiceResponseStatus.Success , then the result of the request changes and it becomes AppServiceResponseStatus.Failure. This way the program counter never steps into the condition if (response.Status == AppServiceResponseStatus.Success).
Any idea about the cause?
Thank you so much for the help.
EDIT
Follow the suggestions, i added an handler for the ServiceClosed event. This is the main class.
public sealed class DriverListener : IBackgroundTask
{
private BackgroundTaskDeferral backgroundTaskDeferral;
private AppServiceConnection appServiceConnection;
public void Run(IBackgroundTaskInstance taskInstance)
{
backgroundTaskDeferral = taskInstance.GetDeferral();
// taskInstance.Canceled += OnTaskCanceled;
var triggerDetails = taskInstance.TriggerDetails as AppServiceTriggerDetails;
appServiceConnection = triggerDetails.AppServiceConnection;
appServiceConnection.RequestReceived += Inbound.OnRequestReceived;
appServiceConnection.ServiceClosed += OnTaskCanceled;
}
private void OnTaskCanceled(AppServiceConnection sender, AppServiceClosedEventArgs reason)
{
if (this.backgroundTaskDeferral != null)
{
Debug.WriteLine("ServiceClosed");
// Complete the service deferral.
this.backgroundTaskDeferral.Complete();
}
}
}
Placing a breakpoint in this function, i see that it was never triggered.
The app connection is opened using the singleton pattern, and putted in a dll that i use in the client app
public static AppServiceConnection GetDriverConnectionInstance()
{
if (_DriverConnectionInstance == null)
{
try
{
_DriverConnectionInstance = OpenDriverConnection().AsTask().GetAwaiter().GetResult();
}
catch
{
}
}
return _DriverConnectionInstance;
}
I also add a Request to the service that toggles a led, and i noticed that the led status changes but the response from the app service is still "Failure" and the message is null.

The AppService has a default lifetime of 25sec, unless it is being requested by the foreground experience. When the service shuts down the connection, your client process will receive the ServiceClosed event, so you know you will need to reopen the connection the next time you want to send a request.

WCF service server throws an exception Cannot access a disposed object

So my service is a simple chat application between two wcf clients. Event callback works when I call events. After I close my client and run it again, and write a message again (to call the event) it throws me exception:
An exception of type 'System.ObjectDisposedException' occurred in
RussianRouletteServiceLibrary.dll but was not handled in user code
Additional information: Cannot access a disposed object.
The code for my service callback is as follows:
private static Action<User, UMessage> gameChat = delegate { };
public void Play()
{
IGameCallback subscriber =
OperationContext.Current.GetCallbackChannel<IGameCallback>();
gameChat += subscriber.PlayerSentMessage;
}
This is the event trigger:
public void SendMessage(User user, UMessage message)
{
try
{
gameChat(user, message);
}
catch (Exception ex)
{
throw ex;
}
}
I get this error every time I .ChannelFactory.Close(); .Close(); the client while closing form event is happening.
Is there anyone that knows how to fix this and is willing to share his knowledge?
Thank you in advance!
EDIT #1
This is the code of the client when it opens:
ConcurrencyMode.Multiple,
UseSynchronizationContext = false)]
public partial class GameForm : Form, IGameCallback
{
#region IGame Callbacks
public void PlayerSentMessage(User user, UMessage message)
{
string nickname = user.NickName == clientUser.NickName ? "You" : user.NickName;
this.Invoke(new MethodInvoker(() => lb_ChatBox.Items.Add(nickname + " : " + message.MessageContent)));
}
#endregion
private GameClient _gameClient = null;
private InstanceContext _instance = null;
private User clientUser = new User(){ Email = "zigm4s#gmail.com", Id = 0, FirstName = "Zigmas", LastName = "Slusnys", NickName = "Ziggy", Password = "test123"};
public GameForm()
{
string state;
if (_gameClient != null)
{
MessageBox.Show("nelygu null");
MessageBox.Show(_gameClient.State.ToString());
//_gameClient = new GameClient(new InstanceContext(this));
}
else
{
_gameClient = new GameClient(new InstanceContext(this));
MessageBox.Show(_gameClient.State.ToString());
}
InitializeComponent();
try
{
_gameClient.Open();
_gameClient.Play();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
This is when the client form is closing.
private void GameForm_FormClosing(object sender, FormClosingEventArgs e)
{
try {
if (_gameClient.State != System.ServiceModel.CommunicationState.Faulted)
{
MessageBox.Show("Closing client");
_gameClient.ChannelFactory.Close();
_gameClient.Close();
}
else
{
MessageBox.Show("Aborting client");
_gameClient.Abort();
}
}
catch(Exception ex)
{ MessageBox.Show(ex.ToString());}
}
EDIT #2
I found the mistake, on the service side i had delegates that were static. It doesn't throw this error when it's not static.

How to stop Windows service programmatically

About programming Windows services: how to stop my windows service?
Here is a very simplified example code(C#):
// Here is my service class (MyTestService.cs).
public class MyTestService:ServiceBase{
// Constructor.
public MyTestService(){
this.ServiceName = "My Test Service";
return;
}
};
// My application class (ApplicationClass.cs).
public static class ApplicationClass{
// Here is main Main() method.
public static void Main(){
// 1. Creating a service instance
// and running it using ServiceBase.
MyTestService service = new MyTestService();
ServiceBase.Run(service);
// 2. Performing a test shutdown of a service.
service.Stop();
Environment.Exit(0);
return;
};
};
So: I've just created "My Test Service" started it and stopped. But when I'm looking into my Services.msc - "My Test Service" is continues to running and stops ONLY when I click a "Stop" link. Why? - why service.Stop() command does nothing?
ServiceController.Stop() also does nothing!
How can I stop my service from Main() method?

The Stop-function sends a stop-signal. It does not wait till the signal is received and processed.
You will have to wait till the Stop-signal has done it's work. You can do that by calling WaitForStatus:
service.Stop();
service.WaitForStatus(ServiceControllerStatus.Stopped);
See for more info: http://msdn.microsoft.com/nl-nl/library/system.serviceprocess.servicecontroller.waitforstatus(v=vs.71).aspx
Environment.Exit is a nasty one. DO NOT USE IT! It aborts your application the hard way, without performing any cleanup in finally blocks, without calling finalizer methods by the GC, it terminates all other forground threads, etc. I can imagine that your application is aborted before the stop-signal even left your application.

I am using following functions in my project
public static ServiceController GetService(string serviceName)
{
ServiceController[] services = ServiceController.GetServices();
return services.FirstOrDefault(_ => Contracts.Extensions.CompareStrings(_.ServiceName, serviceName));
}
public static bool IsServiceRunning(string serviceName)
{
ServiceControllerStatus status;
uint counter = 0;
do
{
ServiceController service = GetService(serviceName);
if (service == null)
{
return false;
}
Thread.Sleep(100);
status = service.Status;
} while (!(status == ServiceControllerStatus.Stopped ||
status == ServiceControllerStatus.Running) &&
(++counter < 30));
return status == ServiceControllerStatus.Running;
}
public static bool IsServiceInstalled(string serviceName)
{
return GetService(serviceName) != null;
}
public static void StartService(string serviceName)
{
ServiceController controller = GetService(serviceName);
if (controller == null)
{
return;
}
controller.Start();
controller.WaitForStatus(ServiceControllerStatus.Running);
}
public static void StopService(string serviceName)
{
ServiceController controller = GetService(serviceName);
if (controller == null)
{
return;
}
controller.Stop();
controller.WaitForStatus(ServiceControllerStatus.Stopped);
}

In your code example service.Stop() and ServiceController.Stop() commands does nothing because they are not called while service is running since ServiceBase.Run(service) is blocking operation and it returns only on stop of the service.