ASP.NET Core - Log exceptions to the IIS log

This is only applicable when you are NOT using MVC in your application

1. Required Packages : 

• Microsoft.Extensions.Logging
• Microsoft.Extensions.Logging.Console

2. Middleware for Exception Login : 

public class ExceptionLoggingMiddleware  
 {  
   private readonly RequestDelegate _next;  
   private readonly ILogger<ExceptionLoggingMiddleware> _logger;  
   public ExceptionLoggingMiddleware(RequestDelegate next, ILogger<ExceptionLoggingMiddleware> logger)  
   {  
     _next = next;  
     _logger = logger;  
   }  
   public async Task InvokeAsync(HttpContext context)  
   {  
     try  
     {  
       await _next(context);  
     }  
     catch (Exception ex)  
     {  
       _logger.LogError(ex, "An unhandled exception occurred.");  
       throw; // Rethrow the exception after logging it  
     }  
   }  
 }  

3. Configure your Program.cs

 using Microsoft.AspNetCore.Builder;  
 using Microsoft.AspNetCore.Hosting;  
 using Microsoft.Extensions.DependencyInjection;  
 using Microsoft.Extensions.Hosting;  
 using Microsoft.Extensions.Logging;  
 var builder = WebApplication.CreateBuilder(args);  
 // Configure logging  
 builder.Logging.ClearProviders();  
 builder.Logging.AddConsole();  
 builder.Logging.AddFile("Logs/app-{Date}.log");   
 var app = builder.Build();  
 // Add custom middleware for exception logging  
 app.UseMiddleware<ExceptionLoggingMiddleware>();  
 // Define endpoints  
 app.MapGet("/", () => "Hello World!");  
 app.Run();  
 public class ExceptionLoggingMiddleware  
 {  
   private readonly RequestDelegate _next;  
   private readonly ILogger<ExceptionLoggingMiddleware> _logger;  
   public ExceptionLoggingMiddleware(RequestDelegate next, ILogger<ExceptionLoggingMiddleware> logger)  
   {  
     _next = next;  
     _logger = logger;  
   }  
   public async Task InvokeAsync(HttpContext context)  
   {  
     try  
     {  
       await _next(context);  
     }  
     catch (Exception ex)  
     {  
       _logger.LogError(ex, "An unhandled exception occurred.");  
       throw; // Rethrow the exception after logging it  
     }  
   }  
 }  

4.  Set Up File Permissions for IIS

• Create a Logs directory in your application root
• Right-click the Logs folder in Windows Explorer.
• Go to Properties.
• Navigate to the Security tab.
• Click Edit, then Add, and enter IIS_IUSRS.
• Grant Write permissions to the IIS_IUSRS user.