What is Serilog, how is it used?

Warnings, messages, errors. We would like to log all of them and follow them from time to time. By looking at these logs, we direct the flow in our system and the correction of the fault directions. We will show you how to configure Serilog in this topic.

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First, let's install these two packages. Nuget

Install-Package Serilog.AspNetCore -Version 3.4.0

Nuget

Install-Package Serilog.Sinks.File -Version 4.1.0

Open Startup.cs and make the following configurations.

public void ConfigureServices(IServiceCollection services)
{
    Log.Logger = new LoggerConfiguration()
        .MinimumLevel.Warning()
        .Enrich.FromLogContext()
        .WriteTo.Debug(new RenderedCompactJsonFormatter())
        .WriteTo.File(Path.Combine("logs", "logs.txt"), rollingInterval: RollingInterval.Day)
        .WriteTo.Console()
        .CreateLogger();
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    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);
        };
    });
}

Things to do in Program.cs.

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Serilog;

namespace Project.UI
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSerilog()
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

After doing these configurations, remove all records belonging to Logging section in appsettings.json. According to the structure we have realized above. Your logs will be saved daily under the logs folder. You can change the scope of logging by changing the MinimumLevel.Warning level.

Log.Warning("System Warning");
Log.Information("System Information");
Log.Fatal(new Exception("Test Error"), "System Exception");

Place the codes above in HomeController. Run your project and look at the console records and changes in the logs folder. When you see the result, you will have realized what you can do.

Good work..