Serilog 與 ASP.NET Core 6.0 範例

appsettings.json

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft.AspNetCore": "Warning"
      }
    },
    "Enrich": [ "FromLogContext" ],
    "WriteTo": [
      {
        "Name": "Console"
      },
      {
        "Name": "File",
        "Args": {
            "path":  "./logs/log-.json",
            "rollingInterval": "Day",
            "formatter": "Serilog.Formatting.Compact.CompactJsonFormatter, Serilog.Formatting.Compact"
          }
      }
    ]
  },
  "AllowedHosts": "*"
}

Program.cs

using Serilog;
using Serilog.Events;

var builder = WebApplication.CreateBuilder(args);

Log.Logger = new LoggerConfiguration()
    .ReadFrom.Configuration(builder.Configuration)
    .CreateLogger();

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

    // Add services to the container.

    builder.Services.AddControllers();
    // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
    builder.Services.AddEndpointsApiExplorer();
    builder.Services.AddSwaggerGen();

    builder.WebHost.UseSerilog();

    var app = builder.Build();

    // Configure the HTTP request pipeline.
    if (app.Environment.IsDevelopment())
    {
        app.UseSwagger();
        app.UseSwaggerUI();
    }

    app.UseHttpsRedirection();

    app.UseSerilogRequestLogging(options =>
    {
        // 如果要自訂訊息的範本格式，可以修改這裡，但修改後並不會影響結構化記錄的屬性
        options.MessageTemplate = "Handled {RequestPath}";

        // 預設輸出的紀錄等級為 Information，你可以在此修改記錄等級
        // options.GetLevel = (httpContext, elapsed, ex) => LogEventLevel.Debug;

        // 你可以從 httpContext 取得 HttpContext 下所有可以取得的資訊！
        options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
        {
            diagnosticContext.Set("RequestHost", httpContext.Request.Host.Value);
            diagnosticContext.Set("RequestScheme", httpContext.Request.Scheme);
            diagnosticContext.Set("UserID", httpContext.User.Identity?.Name);
        };
    });

    app.UseAuthorization();

    app.MapControllers();

    app.Run();

    return 0;
}
catch (Exception ex)
{
    Log.Fatal(ex, "Host terminated unexpectedly");
    return 1;
}
finally
{
    Log.CloseAndFlush();
}

WeatherForecastController.cs

using Microsoft.AspNetCore.Mvc;
using Serilog;

namespace serilogdemo2.Controllers;

[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
    private static readonly string[] Summaries = new[]
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    private readonly ILogger<WeatherForecastController> _logger;
    private readonly IDiagnosticContext _diagnosticContext;

    public WeatherForecastController(ILogger<WeatherForecastController> logger, IDiagnosticContext diagnosticContext)
    {
        _logger = logger;
        _diagnosticContext = diagnosticContext;
    }

    [HttpGet(Name = "GetWeatherForecast")]
    public IEnumerable<WeatherForecast> Get()
    {
        _diagnosticContext.Set("UserID", User.Identity?.Name);

        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = DateTime.Now.AddDays(index),
            TemperatureC = Random.Shared.Next(-20, 55),
            Summary = Summaries[Random.Shared.Next(Summaries.Length)]
        })
        .ToArray();
    }
}