.NET 项目默认情况下 日志是使用的 ILogger 接口，默认提供一下四种日志记录程序：

• 控制台
• 调试
• EventSource
• EventLog

这四种记录程序都是默认包含在 .NET 运行时库中。关于这四种记录程序的详细介绍可以直接查看微软的官方文档 https://docs.microsoft.com/zh-cn/dotnet/core/extensions/logging-providers

今天给大家分享自己实现一个日志记录程序，继承自  ILogger 接口，实现将日志记录到本地的 txt 文件中，并包含一个自动清理过期日志的功能任务。

类库的整体代码结构如下：

 

 Models 文件夹中存放 LoggerSetting.cs 是 该模块注入服务时需要的配置参数

namespace Logger.LocalFile.Models
{
    public class LoggerSetting
    {
        /// <summary>
        /// 保存天数
        /// </summary>
        public int SaveDays { get; set; } = 7;
    }
}

 

Tasks 文件夹中存放的 LogClearTask.cs 是用于自动清理过期日志的任务，会在日志服务注入的同时启动，会通过配置的保存天数参数，定期删除超过实现的日志文件

using Common;
using Logger.LocalFile.Models;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;

namespace Logger.LocalFile.Tasks
{
    public class LogClearTask : BackgroundService
    {

        private readonly int saveDays;


        public LogClearTask(IOptionsMonitor<LoggerSetting> config)
        {
            saveDays = config.CurrentValue.SaveDays;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                try
                {

                    string basePath = Directory.GetCurrentDirectory().Replace("\\", "/") + "/Logs/";

                    if (Directory.Exists(basePath))
                    {
                        List<string> logPaths = IOHelper.GetFolderAllFiles(basePath).ToList();

                        var deleteTime = DateTime.UtcNow.AddDays(-1 * saveDays);

                        if (logPaths.Count != 0)
                        {
                            foreach (var logPath in logPaths)
                            {
                                var fileInfo = new FileInfo(logPath);

                                if (fileInfo.CreationTimeUtc < deleteTime)
                                {
                                    File.Delete(logPath);
                                }

                            }
                        }
                    }

                }
                catch
                {
                }

                await Task.Delay(1000 * 60 * 60 * 24, stoppingToken);
            }
        }

    }
}

 

ILoggingBuilderExtensions 是应用注入服务的扩展方法，内容如下

using Logger.LocalFile.Models;
using Logger.LocalFile.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Logger.LocalFile
{

    public static class ILoggingBuilderExtensions
    {

        public static void AddLocalFileLogger(this ILoggingBuilder builder, Action<LoggerSetting> action)
        {
            builder.Services.Configure(action);
            builder.Services.AddSingleton<ILoggerProvider, LocalFileLoggerProvider>();
            builder.Services.AddSingleton<IHostedService, LogClearTask>();
        }
    }
}

 

LocalFileLogger 是日志的保存执行方法，内容如下

using Common;
using Microsoft.Extensions.Logging;
using System.Text;

namespace Logger.LocalFile
{
    public class LocalFileLogger : ILogger
    {
        private readonly string categoryName;
        private readonly string basePath;

        public LocalFileLogger(string categoryName)
        {
            this.categoryName = categoryName;

            basePath = Directory.GetCurrentDirectory().Replace("\\", "/") + "/Logs/";

            if (Directory.Exists(basePath) == false)
            {
                Directory.CreateDirectory(basePath);
            }
        }

        public IDisposable BeginScope<TState>(TState state)
        {
            return default!;
        }

        public bool IsEnabled(LogLevel logLevel)
        {
            if (logLevel != LogLevel.None)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
        {
            if (IsEnabled(logLevel))
            {
                if (state != null && state.ToString() != null)
                {
                    var logContent = state.ToString();

                    if (logContent != null)
                    {
                        if (exception != null)
                        {
                            var logMsg = new
                            {
                                message = logContent,
                                error = new
                                {
                                    exception?.Source,
                                    exception?.Message,
                                    exception?.StackTrace
                                }
                            };

                            logContent = JsonHelper.ObjectToJson(logMsg);
                        }

                        var log = new
                        {
                            CreateTime = DateTime.UtcNow,
                            Category = categoryName,
                            Level = logLevel.ToString(),
                            Content = logContent
                        };

                        string logStr = JsonHelper.ObjectToJson(log);

                        var logPath = basePath + DateTime.UtcNow.ToString("yyyyMMddHH") + ".log";

                        File.AppendAllText(logPath, logStr + Environment.NewLine, Encoding.UTF8);

                    }
                }
            }
        }
    }
}

 

LocalFileLoggerProvider 是Logger执行方法向外部的供应者，内容如下：

using Microsoft.Extensions.Logging;
using System.Collections.Concurrent;

namespace Logger.LocalFile
{
    public class LocalFileLoggerProvider : ILoggerProvider
    {
        private readonly ConcurrentDictionary<string, LocalFileLogger> loggers = new();

        public ILogger CreateLogger(string categoryName)
        {
            return loggers.GetOrAdd(categoryName, new LocalFileLogger(categoryName));
        }

        public void Dispose()
        {
            loggers.Clear();
            GC.SuppressFinalize(this);
        }
    }
}

 

当我们其他项目想要使用我们这个 Logger.LocalFile 类库时，只要添加该类库的引用，然后在启动服务时进行注入即可，注入方法如下：

Web 项目注入方式

//注册本地文件日志服务
builder.Logging.AddLocalFileLogger(options => { options.SaveDays = 7; });

 

控制台项目注入方式

.ConfigureLogging((hostContext, builder) =>
                {
                    //注册本地文件日志服务
                    builder.AddLocalFileLogger(options => { options.SaveDays = 7; });
                })
                .Build();

 

Web 项目直接在 builder 后面编写注入就可以，控制台项目需要先 .ConfigureLogging 才可以，这是两者的区别。

这样就注入了我们自己编写的日志记录程序，项目运行时会在项目的 Logs 文件夹中产生日志文件，如下图