Apache log4net™ กับ .NET 6 WebApi

สร้างโปรเจ็กส์แบบ ASP.NET Core Web API

ที่ไฟล์ Controllers/WeatherForecastController.cs เพิ่มโค๊ด _logger.* ไว้ดูผลการ log

using Microsoft.AspNetCore.Mvc;

namespace WebApi1.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;

        public WeatherForecastController(ILogger<WeatherForecastController> logger)
        {
            _logger = logger;
        }

        [HttpGet(Name = "GetWeatherForecast")]
        public IEnumerable<WeatherForecast> Get()
        {
            _logger.LogInformation("This is an INFORMATION message.");
            _logger.LogWarning("This is a WARNING message.");
            _logger.LogError("This is an ERROR message.");

            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();
        }
    }
}

เปิดหน้าต่าง Output โดยไปที่เมนู View | Output

ทดลองเรียก WeatherForecast เช่น https://localhost:7244/WeatherForecast แล้วดูที่หน้าต่าง Output

WebApi1.Controllers.WeatherForecastController: Information: This is an INFORMATION message.
WebApi1.Controllers.WeatherForecastController: Warning: This is a WARNING message.
WebApi1.Controllers.WeatherForecastController: Error: This is an ERROR message.

ติดตั้ง Package log4net และ Microsoft.Extensions.Logging.Log4Net.AspNetCore

PM> Install-Package log4net -Version 2.0.13
PM> Install-Package Microsoft.Extensions.Logging.Log4Net.AspNetCore -Version 6.0.0

สร้างไฟล์ log4net.config

<log4net>
	<root>
		<level value="ALL" />
		<appender-ref ref="file" />
	</root>
	<appender name="file" type="log4net.Appender.RollingFileAppender">
		<file value="net6demo.log" />
		<appendToFile value="true" />
		<rollingStyle value="Size" />
		<maxSizeRollBackups value="5" />
		<maximumFileSize value="10MB" />
		<staticLogFileName value="true" />
		<layout type="log4net.Layout.PatternLayout">
			<conversionPattern value="%date [%thread] %level %logger - %message%newline" />
		</layout>
	</appender>
</log4net>

หรือ

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
    <file value="log/" />
    <datePattern value="yyMMdd'Jack.log'" />
    <staticLogFileName value="false"/>
    <appendToFile value="true"/>
    <rollingStyle value="Date"/>
    <maxSizeRollBackups value="100"/>
    <maximumFileSize value="15MB"/>
    <encoding value="UTF-8"/>
    <layout type="log4net.Layout.PatternLayout">
      <param name="ConversionPattern" value="%-5p%d{ HH:mm:ss} li:%line - [%method] %m  %n" />
    </layout>
  </appender>
  <root>
    <level value="ALL"/>
    <appender-ref ref="RollingLogFileAppender"/>
  </root>
</log4net>

.NET 5 แก้ไขไฟล์ Start.cs

        public void ConfigureServices(IServiceCollection services)
        {

            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "EWBranchAPI", Version = "v1" });
            });

            ILoggerFactory _loggerFactory = (ILoggerFactory)new LoggerFactory();
            _loggerFactory.AddLog4Net();
            services.AddSingleton(_loggerFactory);
        }

.NET 6 แก้ไขไฟล์ Program.cs

var builder = WebApplication.CreateBuilder(args);

ILoggerFactory _loggerFactory = (ILoggerFactory)new LoggerFactory();
_loggerFactory.AddLog4Net();
builder.Services.AddSingleton(_loggerFactory);

// 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();

var app = builder.Build();

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

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.Run();

ทดลองเรียก WeatherForecast อีกครั้งจะได้ไฟล์ .log

2021-12-15 21:21:44,620 [.NET ThreadPool Worker] INFO WebApi1.Controllers.WeatherForecastController - This is an INFORMATION message.
2021-12-15 21:21:44,641 [.NET ThreadPool Worker] WARN WebApi1.Controllers.WeatherForecastController - This is a WARNING message.
2021-12-15 21:21:44,643 [.NET ThreadPool Worker] ERROR WebApi1.Controllers.WeatherForecastController - This is an ERROR message.