scott-xu / serilog-extensions-hosting

Serilog logging for Microsoft.Extensions.Hosting

Serilog.Extensions.Hosting

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

ASP.NET Core applications should consider using Serilog.AspNetCore instead, which bundles this package and includes other ASP.NET Core-specific features.

Instructions

First, install the Serilog.Extensions.Hosting NuGet package into your app. You will need a way to view the log messages - Serilog.Sinks.Console writes these to the console; there are many more sinks available on NuGet.

Install-Package Serilog.Extensions.Hosting -DependencyVersion Highest
Install-Package Serilog.Sinks.Console

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

public class Program
{
    public static int Main(string[] args)
    {
        Log.Logger = new LoggerConfiguration()
            .MinimumLevel.Debug()
            .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
            .Enrich.FromLogContext()
            .WriteTo.Console()
            .CreateLogger();

        try
        {
            Log.Information("Starting host");
            BuildHost(args).Run();
            return 0;
        }
        catch (Exception ex)
        {
            Log.Fatal(ex, "Host terminated unexpectedly");
            return 1;
        }
        finally
        {
            Log.CloseAndFlush();
        }
    }

Then, add UseSerilog() to the host builder in BuildHost().

    public static IHost BuildHost(string[] args) =>
        new HostBuilder()
            .ConfigureServices(services => services.AddSingleton<IHostedService, PrintTimeService>())
            .UseSerilog() // <- Add this line
            .Build();
}

Finally, clean up by removing the remaining "Logging" section from appsettings.json files (this can be replaced with Serilog configuration as shown in this example, if required)

That's it! You will see log output like:

[22:10:39 INF] Getting the motors running...
[22:10:39 INF] The current time is: 12/05/2018 10:10:39 +00:00

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

Using the package

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

Tip: change the minimum level for Microsoft to Warning

Inline initialization

You can alternatively configure Serilog using a delegate as shown below:

    // dotnet add package Serilog.Settings.Configuration
    .UseSerilog((hostingContext, loggerConfiguration) => loggerConfiguration
        .ReadFrom.Configuration(hostingContext.Configuration)
        .Enrich.FromLogContext()
        .WriteTo.Console())

This has the advantage of making the hostingContext's Configuration object available for configuration of the logger, but at the expense of recording Exceptions raised earlier in program startup.

If this method is used, Log.Logger is assigned implicitly, and closed when the app is shut down.