how to configure asp.net.core ihostservice with global exception handler

You can set up a try-catch block at the top level in your IHost or implement a custom middleware-like mechanism for services running in the host.

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        var host = Host.CreateDefaultBuilder(args)
            .ConfigureServices((context, services) =>
            {
                services.AddHostedService<MyService>();
                services.AddSingleton<IGlobalExceptionHandler, GlobalExceptionHandler>();
            })
            .Build();

        try
        {
            await host.RunAsync();
        }
        catch (Exception ex)
        {
            var logger = host.Services.GetRequiredService<ILogger<Program>>();
            logger.LogError(ex, "An unhandled exception occurred in the host.");
        }
    }
}

public class MyService : IHostedService
{
    private readonly ILogger<MyService> _logger;
    private readonly IGlobalExceptionHandler _exceptionHandler;

    public MyService(ILogger<MyService> logger, IGlobalExceptionHandler exceptionHandler)
    {
        _logger = logger;
        _exceptionHandler = exceptionHandler;
    }

    public async Task StartAsync(CancellationToken cancellationToken)
    {
        try
        {
            _logger.LogInformation("Service is starting...");
            // Simulate work
            throw new InvalidOperationException("Simulated exception in service.");
        }
        catch (Exception ex)
        {
            _exceptionHandler.HandleException(ex);
        }
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Service is stopping...");
        return Task.CompletedTask;
    }
}

public interface IGlobalExceptionHandler
{
    void HandleException(Exception ex);
}

public class GlobalExceptionHandler : IGlobalExceptionHandler
{
    private readonly ILogger<GlobalExceptionHandler> _logger;

    public GlobalExceptionHandler(ILogger<GlobalExceptionHandler> logger)
    {
        _logger = logger;
    }

    public void HandleException(Exception ex)
    {
        // Log or take other appropriate actions
        _logger.LogError(ex, "An exception occurred.");
    }
}