.NET 6 Serilog進階範例

目的

讀取appsetting設定檔
二階段初始化
為了簡單化故將Log存入SQLite

建立新專案

選擇ASP.NET Core Web API專案範本，並執行下一步

設定新的專案

命名你的專案名稱，並選擇專案要存放的位置。

其他資訊

直接進行下一步

NuGet加入套件

Serilog.AspNetCore
Serilog.Sinks.SQLite

編輯Program.cs檔

using Serilog;
 //第一階段初始化
 // var builder = WebApplication.CreateBuilder(args);未使用二階段參數化，builder會跑到try外面
Log.Logger = new LoggerConfiguration()
  //.ReadFrom.Configuration(builder.Configuration)
  .CreateBootstrapLogger();
try {
  var builder = WebApplication.CreateBuilder(args);
  // 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();
  //第二階段初始化可以取得appsetting的內容，如不使用第二階段初始化，
  //會需要將 var builder宣告式會移出try(如上方註解處)，就會有風險未捕獲builder的錯誤
  builder.Host.UseSerilog(
      (hostingContext, services, loggerConfiguration) => {
        //使用appsetting
        loggerConfiguration.ReadFrom.Configuration(builder.Configuration);
      });
  var app = builder.Build();

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

  app.UseHttpsRedirection();
  //紀錄每個Request的資料，須注意要放在讀取靜態檔案(app.UseStaticFiles())後面，因為靜態檔案的狀態通常不需要紀錄資訊
  app.UseSerilogRequestLogging();
  //以下省略

編輯appsetting.json

設定Serilog，包含

最低紀錄標準為Information
Microsoft.AspNetCore開頭類別紀錄標準為Warning
寫Log檔到console
寫Log檔到File，並請用日期分割檔案
寫Log檔到SQLite，資料表名稱為Logs，限制DB最大為1M，預設還有一個參數rollOver為true，當達到限制，就會分割DB

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft.AspNetCore": "Warning"
      }
    },
    "WriteTo": [
      { "Name": "Console" },
      {
        "Name": "File",
        "Args": {
          "path": "./logs/log-.txt",
          "rollingInterval": "Day"
        }
      },
      {
        "Name": "SQLite",
        "Args": {
          "sqliteDbPath": "../../../logs/log.sqlite",
          "tableName": "Logs",
          "maxDatabaseSize": 1
        }
      }
    ]
  },
  "AllowedHosts": "*"
}

編輯WeatherForecastController.cs類別檔

    [HttpGet(Name = "GetWeatherForecast")]
    public IEnumerable<WeatherForecast> Get() {
      //新增一個類型
      var StudentObject = new Student() { Id = 4, Name = "Bill", Age = 20 };
      //新增一個匿名類型
      var position = new { Latitude = 25, Longitude = 134 };
      //寫log等級為error的log，當需要紀錄物件時需要透過{@該物件}來表示
      _logger.LogError("Error Value: {@StudentObject}", StudentObject);
      _logger.LogError("Error Value: {@position}", position);
      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();
    }
    public class Student {
      public int Id { get; set; }
      public string Name { get; set; }
      public int Age { get; set; }
    }