Serilog.AspNetCore 9.0.0-dev-02302

Serilog.AspNetCore Build status NuGet Version

Serilog logging for ASP.NET Core. This package routes ASP.NET Core log messages through Serilog, so you can get information about ASP.NET's internal operations written to the same Serilog sinks as your application events.

With Serilog.AspNetCore installed and configured, you can write log messages directly through Serilog or any ILogger interface injected by ASP.NET. All loggers will use the same underlying implementation, levels, and destinations.

Versioning: This package tracks the versioning and target framework support of its Microsoft.Extensions.Hosting dependency. Most users should choose the version of Serilog.AspNetCore that matches their application's target framework. I.e. if you're targeting .NET 7.x, choose a 7.x version of Serilog.AspNetCore. If you're targeting .NET 8.x, choose an 8.x Serilog.AspNetCore version, and so on.

Instructions

First, install the Serilog.AspNetCore NuGet package into your app.

dotnet add package Serilog.AspNetCore

Next, in your application's Program.cs file, configure Serilog first. A try/catch block will ensure any configuration issues are appropriately logged:

using Serilog;

Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .CreateLogger();

try
{
    Log.Information("Starting web application");

    var builder = WebApplication.CreateBuilder(args);
    builder.Services.AddSerilog(); // <-- Add this line
    
    var app = builder.Build();
    app.MapGet("/", () => "Hello World!");

    app.Run();
}
catch (Exception ex)
{
    Log.Fatal(ex, "Application terminated unexpectedly");
}
finally
{
    Log.CloseAndFlush();
}

The builder.Services.AddSerilog() call will redirect all log events through your Serilog pipeline.

Finally, clean up by removing the remaining configuration for the default logger, including the "Logging" section from appsettings.*.json files (this can be replaced with Serilog configuration as shown in the Sample project, if required).

That's it! With the level bumped up a little you will see log output resembling:

[12:01:43 INF] Starting web application
[12:01:44 INF] Now listening on: http://localhost:5000
[12:01:44 INF] Application started. Press Ctrl+C to shut down.
[12:01:44 INF] Hosting environment: Development
[12:01:44 INF] Content root path: serilog-aspnetcore/samples/Sample
[12:01:47 WRN] Failed to determine the https port for redirect.
[12:01:47 INF] Hello, world!
[12:01:47 INF] HTTP GET / responded 200 in 95.0581 ms

Tip: to see Serilog output in the Visual Studio output window when running under IIS, either select ASP.NET Core Web Server from the Show output from drop-down list, or replace WriteTo.Console() in the logger configuration with WriteTo.Debug().

A more complete example, including appsettings.json configuration, can be found in the sample project here.

Request logging

The package includes middleware for smarter HTTP request logging. The default request logging implemented by ASP.NET Core is noisy, with multiple events emitted per request. The included middleware condenses these into a single event that carries method, path, status code, and timing information.

As text, this has a format like:

[16:05:54 INF] HTTP GET / responded 200 in 227.3253 ms

Or as JSON:

{
  "@t": "2019-06-26T06:05:54.6881162Z",
  "@mt": "HTTP {RequestMethod} {RequestPath} responded {StatusCode} in {Elapsed:0.0000} ms",
  "@r": ["224.5185"],
  "RequestMethod": "GET",
  "RequestPath": "/",
  "StatusCode": 200,
  "Elapsed": 224.5185,
  "RequestId": "0HLNPVG1HI42T:00000001",
  "CorrelationId": null,
  "ConnectionId": "0HLNPVG1HI42T"
}

To enable the middleware, first change the minimum level for the noisy ASP.NET Core log sources to Warning in your logger configuration or appsettings.json file:

            .MinimumLevel.Override("Microsoft.AspNetCore.Hosting", LogEventLevel.Warning)
            .MinimumLevel.Override("Microsoft.AspNetCore.Mvc", LogEventLevel.Warning)
            .MinimumLevel.Override("Microsoft.AspNetCore.Routing", LogEventLevel.Warning)

Tip: add {SourceContext} to your console logger's output template to see the names of loggers; this can help track down the source of a noisy log event to suppress.

Then, in your application's Program.cs, add the middleware with UseSerilogRequestLogging():

    var app = builder.Build();

    app.UseSerilogRequestLogging(); // <-- Add this line

    // Other app configuration

It's important that the UseSerilogRequestLogging() call appears before handlers such as MVC. The middleware will not time or log components that appear before it in the pipeline. (This can be utilized to exclude noisy handlers from logging, such as UseStaticFiles(), by placing UseSerilogRequestLogging() after them.)

During request processing, additional properties can be attached to the completion event using IDiagnosticContext.Set():

    public class HomeController : Controller
    {
        readonly IDiagnosticContext _diagnosticContext;

        public HomeController(IDiagnosticContext diagnosticContext)
        {
            _diagnosticContext = diagnosticContext ??
                throw new ArgumentNullException(nameof(diagnosticContext));
        }

        public IActionResult Index()
        {
            // The request completion event will carry this property
            _diagnosticContext.Set("CatalogLoadTime", 1423);

            return View();
        }

This pattern has the advantage of reducing the number of log events that need to be constructed, transmitted, and stored per HTTP request. Having many properties on the same event can also make correlation of request details and other data easier.

The following request information will be added as properties by default:

  • RequestMethod
  • RequestPath
  • StatusCode
  • Elapsed

You can modify the message template used for request completion events, add additional properties, or change the event level, using the options callback on UseSerilogRequestLogging():

app.UseSerilogRequestLogging(options =>
{
    // Customize the message template
    options.MessageTemplate = "Handled {RequestPath}";
    
    // Emit debug-level events instead of the defaults
    options.GetLevel = (httpContext, elapsed, ex) => LogEventLevel.Debug;
    
    // Attach additional properties to the request completion event
    options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
    {
        diagnosticContext.Set("RequestHost", httpContext.Request.Host.Value);
        diagnosticContext.Set("RequestScheme", httpContext.Request.Scheme);
    };
});

Two-stage initialization

The example at the top of this page shows how to configure Serilog immediately when the application starts. This has the benefit of catching and reporting exceptions thrown during set-up of the ASP.NET Core host.

The downside of initializing Serilog first is that services from the ASP.NET Core host, including the appsettings.json configuration and dependency injection, aren't available yet.

To address this, Serilog supports two-stage initialization. An initial "bootstrap" logger is configured immediately when the program starts, and this is replaced by the fully-configured logger once the host has loaded.

To use this technique, first replace the initial CreateLogger() call with CreateBootstrapLogger():

using Serilog;
using Serilog.Events;

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
    .Enrich.FromLogContext()
    .WriteTo.Console()
    .CreateBootstrapLogger(); // <-- Change this line!

Then, pass a callback to AddSerilog() that creates the final logger:

builder.Services.AddSerilog((services, lc) => lc
    .ReadFrom.Configuration(builder.Configuration)
    .ReadFrom.Services(services)
    .Enrich.FromLogContext()
    .WriteTo.Console());

It's important to note that the final logger completely replaces the bootstrap logger: if you want both to log to the console, for instance, you'll need to specify WriteTo.Console() in both places, as the example shows.

Consuming appsettings.json configuration

Using two-stage initialization, insert the ReadFrom.Configuration(builder.Configuration) call shown in the example above. The JSON configuration syntax is documented in the Serilog.Settings.Configuration README.

Injecting services into enrichers and sinks

Using two-stage initialization, insert the ReadFrom.Services(services) call shown in the example above. The ReadFrom.Services() call will configure the logging pipeline with any registered implementations of the following services:

  • IDestructuringPolicy
  • ILogEventEnricher
  • ILogEventFilter
  • ILogEventSink
  • LoggingLevelSwitch

JSON output

The Console(), Debug(), and File() sinks all support JSON-formatted output natively, via the included Serilog.Formatting.Compact package.

To write newline-delimited JSON, pass a CompactJsonFormatter or RenderedCompactJsonFormatter to the sink configuration method:

    .WriteTo.Console(new RenderedCompactJsonFormatter())

Writing to the Azure Diagnostics Log Stream

The Azure Diagnostic Log Stream ships events from any files in the D:\home\LogFiles\ folder. To enable this for your app, add a file sink to your LoggerConfiguration, taking care to set the shared and flushToDiskInterval parameters:

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Debug()
    .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
    .Enrich.FromLogContext()
    .WriteTo.Console()
    // Add this line:
    .WriteTo.File(
       System.IO.Path.Combine(Environment.GetEnvironmentVariable("HOME"), "LogFiles", "Application", "diagnostics.txt"),
       rollingInterval: RollingInterval.Day,
       fileSizeLimitBytes: 10 * 1024 * 1024,
       retainedFileCountLimit: 2,
       rollOnFileSizeLimit: true,
       shared: true,
       flushToDiskInterval: TimeSpan.FromSeconds(1))
    .CreateLogger();

Pushing properties to the ILogger<T>

If you want to add extra properties to all log events in a specific part of your code, you can add them to the ILogger<T> in Microsoft.Extensions.Logging with the following code. For this code to work, make sure you have added the .Enrich.FromLogContext() to the .UseSerilog(...) statement, as specified in the samples above.

// Microsoft.Extensions.Logging ILogger<T>
// Yes, it's required to use a dictionary. See https://nblumhardt.com/2016/11/ilogger-beginscope/
using (logger.BeginScope(new Dictionary<string, object>
{
    ["UserId"] = "svrooij",
    ["OperationType"] = "update",
}))
{
   // UserId and OperationType are set for all logging events in these brackets
}

The code above results in the same outcome as if you would push properties in the LogContext in Serilog. More details can be found in https://github.com/serilog/serilog/wiki/Enrichment#the-logcontext.

// Serilog LogContext
using (LogContext.PushProperty("UserId", "svrooij"))
using (LogContext.PushProperty("OperationType", "update"))
{
    // UserId and OperationType are set for all logging events in these brackets
}

Showing the top 20 packages that depend on Serilog.AspNetCore.

Packages Downloads
Convey.Logging
Convey.Logging
16
Convey.Logging
Convey.Logging
15
Convey.Logging
Convey.Logging
14

.NET Framework 4.6.2

.NET Standard 2.0

.NET Standard 2.1

.NET 9.0

.NET 8.0

Version Downloads Last updated
9.0.0 14 01/18/2025
9.0.0-dev-02302 13 01/18/2025
9.0.0-dev-02301 10 11/27/2024
8.0.3 15 11/23/2024
8.0.3-dev-00346 12 11/27/2024
8.0.2 16 10/05/2024
8.0.2-dev-00341 16 08/29/2024
8.0.2-dev-00338 16 10/05/2024
8.0.2-dev-00336 14 11/16/2024
8.0.2-dev-00334 15 10/05/2024
8.0.1 12 05/27/2024
8.0.1-dev-00329 15 10/05/2024
8.0.0 12 03/01/2024
8.0.0-dev-00323 16 09/23/2024
7.0.1-dev-00320 11 10/06/2024
7.0.0 12 10/05/2024
7.0.0-dev-00315 14 10/05/2024
7.0.0-dev-00314 12 11/18/2024
7.0.0-dev-00304 14 11/18/2024
7.0.0-dev-00302 15 11/18/2024
6.1.1-dev-00295 14 11/18/2024
6.1.1-dev-00293 15 11/03/2024
6.1.0 16 12/13/2022
6.1.0-dev-00289 11 10/27/2024
6.1.0-dev-00285 14 11/07/2024
6.1.0-dev-00281 14 11/18/2024
6.0.1 14 10/05/2024
6.0.1-dev-00280 11 11/18/2024
6.0.1-dev-00275 12 09/25/2024
6.0.0 11 11/07/2024
6.0.0-dev-00270 13 10/05/2024
6.0.0-dev-00265 10 10/06/2024
5.0.1-dev-00264 13 11/18/2024
5.0.1-dev-00262 12 11/18/2024
5.0.0 61 03/13/2022
5.0.0-dev-00259 15 10/05/2024
4.1.1-dev-00250 14 10/19/2024
4.1.1-dev-00241 11 11/18/2024
4.1.1-dev-00229 11 10/05/2024
4.1.1-dev-00227 12 09/19/2024
4.1.0 113 12/09/2021
4.1.0-dev-00223 10 10/05/2024
4.0.1-dev-00222 14 11/05/2024
4.0.1-dev-00219 12 10/05/2024
4.0.0 41 11/30/2021
4.0.0-dev-00210 16 09/21/2024
4.0.0-dev-00208 12 10/12/2024
4.0.0-dev-00206 14 10/05/2024
4.0.0-dev-00204 14 10/03/2024
4.0.0-dev-00202 13 11/18/2024
4.0.0-dev-00199 13 11/18/2024
4.0.0-dev-00198 10 10/09/2024
3.4.1-dev-00188 14 10/05/2024
3.4.1-dev-00180 16 11/18/2024
3.4.0 11 10/05/2024
3.4.0-dev-00177 10 11/18/2024
3.4.0-dev-00176 15 10/04/2024
3.4.0-dev-00174 14 10/08/2024
3.4.0-dev-00173 14 10/05/2024
3.4.0-dev-00171 14 11/18/2024
3.4.0-dev-00168 14 11/18/2024
3.4.0-dev-00167 10 11/18/2024
3.3.0-dev-00161 12 10/03/2024
3.3.0-dev-00160 13 10/05/2024
3.3.0-dev-00152 13 10/24/2024
3.3.0-dev-00149 14 11/18/2024
3.2.1-dev-00147 13 10/05/2024
3.2.1-dev-00142 15 11/18/2024
3.2.0 14 11/23/2024
3.2.0-dev-00135 15 10/05/2024
3.2.0-dev-00133 15 11/18/2024
3.1.1-dev-00132 11 10/05/2024
3.1.0 11 10/30/2024
3.1.0-dev-00122 14 11/18/2024
3.1.0-dev-00119 12 11/18/2024
3.1.0-dev-00118 13 10/04/2024
3.0.1-dev-00116 14 11/18/2024
3.0.1-dev-00110 14 10/13/2024
3.0.1-dev-00109 9 11/18/2024
3.0.1-dev-00099 12 10/18/2024
3.0.0 10 10/05/2024
3.0.0-dev-00093 14 10/05/2024
3.0.0-dev-00088 10 11/18/2024
3.0.0-dev-00086 10 10/05/2024
3.0.0-dev-00083 11 10/05/2024
3.0.0-dev-00081 11 10/12/2024
3.0.0-dev-00079 13 10/21/2024
3.0.0-dev-00077 13 10/05/2024
3.0.0-dev-00067 15 11/18/2024
3.0.0-dev-00059 12 11/18/2024
3.0.0-dev-00058 12 10/10/2024
3.0.0-dev-00057 12 11/18/2024
3.0.0-dev-00053 12 11/18/2024
3.0.0-dev-00052 12 11/18/2024
3.0.0-dev-00046 15 09/20/2024
3.0.0-dev-00043 15 11/18/2024
3.0.0-dev-00041 13 11/18/2024
3.0.0-dev-00040 10 10/12/2024
2.1.2-dev-00028 14 10/05/2024
2.1.2-dev-00026 14 11/18/2024
2.1.2-dev-00024 15 11/02/2024
2.1.1 13 11/23/2024
2.1.1-dev-00022 12 10/04/2024
2.1.1-dev-00021 13 11/18/2024
2.1.1-dev-00017 16 10/05/2024
2.1.0 12 11/23/2024
2.1.0-dev-00012 16 11/18/2024
2.0.1-dev-00011 15 10/05/2024
2.0.0 14 11/23/2024
2.0.0-dev-00002 14 10/05/2024
2.0.0-dev-00001 15 11/18/2024