Howto find what stopping process from exit?

[dario-l]

I have an aspnetcore application. When I switch to Production then after pressing Ctrl+C I see in the console Application is shutting down... but after that process is still active - exits after a timeout.

How can I find what is cause of that? Which part of my code is holding my application from gracefully exit?

[yassine-krichen]

Hey, so when ASP.NET Core doesn't exit immediately after Ctrl+C, it usually means something in your app is preventing the Host from completing its graceful shutdown. By default, ASP.NET Core gives services 5 seconds (configurable) to clean up before it forces the process to end, which is the timeout you’re seeing.

To find the culprit, here are the most common causes and how to investigate them:

1. Background services not stopping

Anything that implements:

• IHostedService
• BackgroundService
  can block shutdown if StopAsync never completes.

What to check:
Add logging inside all StopAsync or cancellation paths. If you forget to observe stoppingToken, the service may hang.

public override async Task StopAsync(CancellationToken stoppingToken)
{
    _logger.LogInformation("Stopping MyService...");
    await base.StopAsync(stoppingToken);
}

2. Long-running tasks without cancellation

If you started tasks manually using Task.Run, timers, or while-loops, and they ignore the app’s cancellation token, they keep running after Ctrl+C.

What to check:
Search for Task.Run, while(true), or timers without cleanup. Ensure they take and obey a CancellationToken.

---

3. Open connections or servers

Common blockers:

• EF Core DB connections not disposed
• Sockets left open
• Custom IHostedService with a blocking ExecuteAsync

What to check:
Enable Microsoft.Hosting.Lifetime logs. They show which services start and stop and where the shutdown hangs.

In appsettings.json:

{
  "Logging": {
    "LogLevel": {
      "Microsoft.Hosting.Lifetime": "Debug"
    }
  }
}

Then rerun the app and hit Ctrl+C; the logs will tell you which hosted service hasn’t stopped.

---

4. Use "dump" and tools if needed

If you still can’t find it, generate a process dump while it’s stuck and inspect it:

Windows

dotnet dump collect -p <pid>
dotnet dump analyze dump.dmp

Linux

gcore <pid>

Look for:

• Threads waiting indefinitely
• Background tasks still executing
• Hosted services stuck inside loops / blocking I/O

---

5. Increase shutdown logging

You can also hook into host events:

builder.Services.Configure<HostOptions>(options =>
{
    options.ShutdownTimeout = TimeSpan.FromSeconds(30);
});

This gives more time for logging and reveals what’s not finishing in time.

Basically, something in your app isn't respecting cancellation or not finishing during StopAsync(). Turn on Microsoft.Hosting.Lifetime logging, check all background services, and track any long-running operations. That will usually expose the one service blocking your graceful exit.

Hope this helps.