Logging unhandled exceptions via ASP.NET Core middleware

Logging unhandled exceptions

Introduction

The ExceptionHandlingMiddleware class can be added to the ASP.NET Core pipeline to log unhandled exceptions that are thrown during request processing. The unhandled exceptions are caught by this middleware component and are logged through the ILogger implementations that are configured inside the project.

Installation

This feature requires to install our NuGet package

PM > Install-Package Arcus.WebApi.Logging -Version 0.1.0

Usage

To use this middleware, add the following line of code in the Startup.Configure method:

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;

public class Startup
{
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
       app.UseMiddleware<Arcus.WebApi.Logging.ExceptionHandlingMiddleware>();

       ...
       app.UseMvc();
    }
}

If you have multiple middleware components configured, it is advised to put the ExceptionHandlingMiddleware as the first one. By doing so, unhandled exceptions that might occur in other middleware components will also be logged by the ExceptionHandlingMiddleware component.

To get the exceptions logged in Azure Application Insights, configure logging like this when building the IWebHost in Program.cs:

using Microsoft.AspNetCore.Hosting;
using Serilog;

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    private static WebHostBuilder CreateWebHostBuilder(string[] args)
    {
        return WebHost.CreateDefaultBuilder(args)
                      .UseApplicationInsights()
                      .ConfigureLogging(loggers => loggers.AddApplicationInsights())
                      .UseStartup<Startup>();
    }
}

To be able to use the AddApplicationInsights extension method, the Microsoft.Extensions.Logging.ApplicationInsights package must be installed.

If the parameter-less AddApplicationInsights method is used, the configurationsetting ApplicationInsights:TelemetryKey must be specified and the value of the telemetry-key of the Application Insights resource must be set.