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动手造轮子:写一个日志框架

WeihanLi 人气:0

动手造轮子:写一个日志框架

Intro

日志框架有很多,比如 log4net / nlog / serilog / microsoft.extensions.logging 等,如何在切换日志框架的时候做到不用修改代码,只需要切换不同的 loggingProvider 就可以了,最低成本的降低切换日志框架的成本,处于这个考虑自己写了一个日志框架,为不同的日志框架写一个适配,需要用到什么日志框架,配置一下就可以了,业务代码无需变动。

V0

最初的日志强依赖于 log4net,log4net 是我使用的第一个日志框架,所以很长一段时间都在使用它来做日志记录,但是由于是强依赖,在想换日志框架时就会很难受,大量代码要改动,不符合开放封闭的基本原则,于是就有了第一个版本的日志。

V1

第一版的日志参考了微软的日志框架的实现,大概结构如下:

public interface ILogHelperLogFactory
{
    ILogger CreateLogger(string categoryName);
    
    bool AddProvider(ILogHelperProvider provider);
}
public interface ILogHelperLogger
{
    bool IsEnabled(LogHelperLogLevel logLevel);
    void Log(LogHelperLogLevel logLevel, Exception exception, string message);
}
public enum LogHelperLogLevel
{
    /// <summary>
    /// All logging levels
    /// </summary>
    All = 0,

    /// <summary>
    /// A trace logging level
    /// </summary>
    Trace = 1,

    /// <summary>
    /// A debug logging level
    /// </summary>
    Debug = 2,

    /// <summary>
    /// A info logging level
    /// </summary>
    Info = 4,

    /// <summary>
    /// A warn logging level
    /// </summary>
    Warn = 8,

    /// <summary>
    /// An error logging level
    /// </summary>
    Error = 16,

    /// <summary>
    /// A fatal logging level
    /// </summary>
    Fatal = 32,

    /// <summary>
    /// None
    /// </summary>
    None = 64
}
public interface ILogHelperProvider
{
    ILogHelperLogger CreateLogger(string categoryName);
}

为了方便 Logger 的使用,定义了一些扩展方法,使得可以直接使用 logger.Info/logger.Error 等方法,扩展定义如下:

public static void Log(this ILogHelperLogger logger, LogHelperLevel loggerLevel, string msg) => logger.Log(loggerLevel, null, msg);

#region Info

    public static void Info(this ILogHelperLogger logger, string msg, params object[] parameters)
{
    if (parameters == null || parameters.Length == 0)
    {
        logger.Log(LogHelperLevel.Info, msg);
    }
    else
    {
        logger.Log(LogHelperLevel.Info, null, msg.FormatWith(parameters));
    }
}

public static void Info(this ILogHelperLogger logger, Exception ex, string msg) => logger.Log(LogHelperLevel.Info, ex, msg);

public static void Info(this ILogHelperLogger logger, Exception ex) => logger.Log(LogHelperLevel.Info, ex, ex?.Message);

#endregion Info
// ...其他的类似,这里就不详细展开了

如果要自定义的日志记录的话,就实现一个 ILogHelperProvider 即可,实现一个 ILogHelperProvider 就要实现一个 ILogHelperLogger ,原本强依赖的 log4net 可以实现一个 Log4NetLogHelperProvider,这样换别的日志框架的时候只需要实现对应的 ILogHelperProvider 即可,但是从功能性上来说还是很弱的

如果想要某些日志不记录,比如说,Debug 级别的日志不记录,比如说某一个 Logger 下只记录 Error 级别的日志,现在是有些吃力,只能通过 log4net 的配置来限制了,于是就有了第二个版本,增加了 LoggingFilter 可以针对 Provider/Logger/LogLevel/Exception 来设置 filter,过滤不需要记录的日志,这也是参考了微软的日志框架的 Filter,但是实现不太一样,有兴趣的小伙伴可以自己深入研究一下。

V2

V2 版,在 ILogFactory 的接口上增加了 AddFilter 的方法,定义如下:

/// <summary>   
/// Add logs filter 
/// </summary>  
/// <param name="filterFunc">filterFunc, logProviderType/categoryName/Exception, whether to write log</param>   
bool AddFilter(Func<Type, string, LogHelperLogLevel, Exception, bool> filterFunc);

然后定义了一些扩展方法来方便使用:

public static ILogHelperFactory WithMinimumLevel(this ILogHelperFactory logHelperFactory, LogHelperLevel logLevel)
{
    return logHelperFactory.WithFilter(level => level >= logLevel);
}

public static ILogHelperFactory WithFilter(this ILogHelperFactory logHelperFactory, Func<LogHelperLevel, bool> filterFunc)
{
    logHelperFactory.AddFilter((type, categoryName, logLevel, exception) => filterFunc.Invoke(logLevel));
    return logHelperFactory;
}

public static ILogHelperFactory WithFilter(this ILogHelperFactory logHelperFactory, Func<string, LogHelperLevel, bool> filterFunc)
{
    logHelperFactory.AddFilter((type, categoryName, logLevel, exception) => filterFunc.Invoke(categoryName, logLevel));
    return logHelperFactory;
}

public static ILogHelperFactory WithFilter(this ILogHelperFactory logHelperFactory, Func<Type, string, LogHelperLevel, bool> filterFunc)
{
    logHelperFactory.AddFilter((type, categoryName, logLevel, exception) => filterFunc.Invoke(type, categoryName, logLevel));
    return logHelperFactory;
}

public static ILogHelperFactory WithFilter(this ILogHelperFactory logHelperFactory, Func<Type, string, LogHelperLevel, Exception, bool> filterFunc)
{
    logHelperFactory.AddFilter(filterFunc);
    return logHelperFactory;
}

这样就方便了我们只想定义针对 Logger 的 Filter 以及 Provider 的 Filter,不必所有参数都用到,logging filter 现在已经实现了,此时已经使用了 Serilog 做日志记录有一段时间,感觉 Serilog 里的一些设计很优秀,很优雅,于是想把 Serilog 里的一些设计用在自己的日志框架里,比如说:

  1. Serilog 的扩展叫做 Sink,日志输出的地方,Serilog 自定义一个 Sink,很简单只需要实现一个接口,不需要再实现一个 Logger,从这点来说,我觉得 Serilog 比微软的日志框架更加优秀,而且 LogEvent 使得日志更方便的进行批量操作,有需要的可以了解一下 SerilogPeriodBatching https://github.com/serilog/serilog-sinks-periodicbatching

    /// <summary>
    /// A destination for log events.
    /// </summary>
    public interface ILogEventSink
    {
        /// <summary>
        /// Emit the provided log event to the sink.
        /// </summary>
        /// <param name="logEvent">The log event to write.</param>
        void Emit(LogEvent logEvent);
    }
  2. Serilog 可以自定义一些 Enricher,以此来丰富记录的日志内容,比如日志的请求上下文,日志的环境等,也可以是一些固定的属性信息

  3. MessageTemplate,其实微软的日志框架中也有类似的概念,只不过很不明显,用 Serilog 之前我也很少用,微软的日志框架可以这样用 logger.LogInfo("hello {name}", "world") 这样的写法其实就可以把第一个参数当作是 MessageTemplate 或者它内部的叫法 Format

鉴于这么多好处,于是打算将这些功能引入到我的日志框架中

V3

引入 LoggingEvent

说干就干,首先要引入一个 LogHelperLoggingEvent,对应的 SerilogLogEvent,定义如下:

public class LogHelperLoggingEvent : ICloneable
{
    public string CategoryName { get; set; }

    public DateTimeOffset DateTime { get; set; }

    public string MessageTemplate { get; set; }

    public string Message { get; set; }

    public Exception Exception { get; set; }

    public LogHelperLogLevel LogLevel { get; set; }

    public Dictionary<string, object> Properties { get; set; }

    public LogHelperLoggingEvent Copy => (LogHelperLoggingEvent)Clone();

    public object Clone()
    {
        var newEvent = (LogHelperLoggingEvent)MemberwiseClone();
        if (Properties != null)
        {
            newEvent.Properties = new Dictionary<string, object>();
            foreach (var property in Properties)
            {
                newEvent.Properties[property.Key] = property.Value;
            }
        }
        return newEvent;
    }
}

Event 里定义了一个 Properties 的字典用来丰富日志的内容,另外实现了 ICloneable 接口,方便对对象的拷贝,为了强类型,增加了一个 Copy 的方法,返回一个强类型的对象

改造 LogProvider

为了减少扩展一个 ILogProvider 的复杂性,我们要对 ILogProvider 做一个简化,只需要像扩展 Serilog 的 Sink 一样记录日志即可,不需要关心是否要创建 Logger

改造后的定义如下:

public interface ILogHelperProvider
{
    Task Log(LogHelperLoggingEvent loggingEvent);
}

(这里返回了一个 Task,可能返回类型是 void 就足够了,看自己的需要)

这样在实现 LogProvider 的时候只需要实现这个接口就可以了,不需要再实现一个 Logger 了

增加 Enricher

Enricher 定义:

public interface ILogHelperLoggingEnricher
{
    void Enrich(LogHelperLoggingEvent loggingEvent);
}

内置了一个 PropertyEnricher,方便添加一些简单的属性


internal class PropertyLoggingEnricher : ILogHelperLoggingEnricher
{
    private readonly string _propertyName;
    private readonly Func<LogHelperLoggingEvent, object> _propertyValueFactory;
    private readonly bool _overwrite;
    private readonly Func<LogHelperLoggingEvent, bool> _logPropertyPredict = null;

    public PropertyLoggingEnricher(string propertyName, object propertyValue, bool overwrite = false) : this(propertyName, (loggingEvent) => propertyValue, overwrite)
    {
    }

    public PropertyLoggingEnricher(string propertyName, Func<LogHelperLoggingEvent, object> propertyValueFactory,
                                   bool overwrite = false) : this(propertyName, propertyValueFactory, null, overwrite)
    {
    }

    public PropertyLoggingEnricher(string propertyName, Func<LogHelperLoggingEvent, object> propertyValueFactory, Func<LogHelperLoggingEvent, bool> logPropertyPredict,
                                   bool overwrite = false)
    {
        _propertyName = propertyName;
        _propertyValueFactory = propertyValueFactory;
        _logPropertyPredict = logPropertyPredict;
        _overwrite = overwrite;
    }

    public void Enrich(LogHelperLoggingEvent loggingEvent)
    {
        if (_logPropertyPredict?.Invoke(loggingEvent) != false)
        {
            loggingEvent.AddProperty(_propertyName, _propertyValueFactory, _overwrite);
        }
    }
}

ILogFactory 增加一个 AddEnricher 的方法


/// <summary>
/// add log enricher
/// </summary>
/// <param name="enricher">log enricher</param>
/// <returns></returns>
bool AddEnricher(ILogHelperLoggingEnricher enricher);

这样我们在记录日志的时候就可以通过这些 Enricher 丰富 LoggingEvent 中的 Properties 了

为了方便 Property 的操作,我们增加了一些扩展方法:

public static ILogHelperFactory WithEnricher<TEnricher>(this ILogHelperFactory logHelperFactory,
                                                        TEnricher enricher) where TEnricher : ILogHelperLoggingEnricher
{
    logHelperFactory.AddEnricher(enricher);
    return logHelperFactory;
}

public static ILogHelperFactory WithEnricher<TEnricher>(this ILogHelperFactory logHelperFactory) where TEnricher : ILogHelperLoggingEnricher, new()
{
    logHelperFactory.AddEnricher(new TEnricher());
    return logHelperFactory;
}

public static ILogHelperFactory EnrichWithProperty(this ILogHelperFactory logHelperFactory, string propertyName, object value, bool overwrite = false)
{
    logHelperFactory.AddEnricher(new PropertyLoggingEnricher(propertyName, value, overwrite));
    return logHelperFactory;
}

public static ILogHelperFactory EnrichWithProperty(this ILogHelperFactory logHelperFactory, string propertyName, Func<LogHelperLoggingEvent> valueFactory, bool overwrite = false)
{
    logHelperFactory.AddEnricher(new PropertyLoggingEnricher(propertyName, valueFactory, overwrite));
    return logHelperFactory;
}

public static ILogHelperFactory EnrichWithProperty(this ILogHelperFactory logHelperFactory, string propertyName, object value, Func<LogHelperLoggingEvent, bool> predict, bool overwrite = false)
{
    logHelperFactory.AddEnricher(new PropertyLoggingEnricher(propertyName, e => value, predict, overwrite));
    return logHelperFactory;
}

public static ILogHelperFactory EnrichWithProperty(this ILogHelperFactory logHelperFactory, string propertyName, Func<LogHelperLoggingEvent, object> valueFactory, Func<LogHelperLoggingEvent, bool> predict, bool overwrite = false)
{
    logHelperFactory.AddEnricher(new PropertyLoggingEnricher(propertyName, valueFactory, predict, overwrite));
    return logHelperFactory;
}

MessageTemplate

从上面的 LoggingEvent 中已经增加了 MessageTemplate,于是我们引入了微软日志框架中日志的格式化,将 messageTemplate 和 parameters 转换成 Message 和 Properties,具体参考 https://github.com/WeihanLi/WeihanLi.Common/blob/276cc49cfda511f9b7b3bb8344ee52441c4a3b23/src/WeihanLi.Common/Logging/LoggingFormatter.cs

internal struct FormattedLogValue
{
    public string Msg { get; set; }

    public Dictionary<string, object> Values { get; set; }

    public FormattedLogValue(string msg, Dictionary<string, object> values)
    {
        Msg = msg;
        Values = values;
    }
}

internal static class LoggingFormatter
{
    public static FormattedLogValue Format(string msgTemplate, object[] values)
    {
        if (values == null || values.Length == 0)
            return new FormattedLogValue(msgTemplate, null);

        var formatter = new LogValuesFormatter(msgTemplate);
        var msg = formatter.Format(values);
        var dic = formatter.GetValues(values)
            .ToDictionary(x => x.Key, x => x.Value);

        return new FormattedLogValue(msg, dic);
    }
}

这样我们就可以支持 messageTemplate 了,然后来改造一下我们的 Logger

public interface ILogHelperLogger
{
    void Log(LogHelperLogLevel logLevel, Exception exception, string messageTemplate, params object[] parameters);

    bool IsEnabled(LogHelperLogLevel logLevel);
}

与上面不同的是,我们增加了 parameters

再来更新一下我们的扩展方法,上面的扩展方法是直接使用 string.Format 的方式的格式化的,我们这里要更新一下

public static void Info(this ILogHelperLogger logger, string msg, params object[] parameters)
{
    logger.Log(LogHelperLogLevel.Info, null, msg, parameters);
}

public static void Info(this ILogHelperLogger logger, Exception ex, string msg) => logger.Log(LogHelperLogLevel.Info, ex, msg);

public static void Info(this ILogHelperLogger logger, Exception ex) => logger.Log(LogHelperLogLevel.Info, ex, ex?.Message);

至此,功能基本完成,但是从 API 的角度来说,感觉现在的 ILogFactory太重了,这些 AddProvider/AddEnricher/AddFilter 都应该属性 ILogFactory 的内部属性,通过配置来完成,不应该成为它的接口方法,于是就有了下一版

V4

这一版主要是引入了 LoggingBuilder, 通过 LoggingBuilder 来配置内部的 LogFactory 所需要的 Provider/Enricher/Filter,原来他们的配置方法和扩展方法均变成ILogHelperLoggingBuilder

public interface ILogHelperLoggingBuilder
{
    /// <summary>
    /// Adds an ILogHelperProvider to the logging system.
    /// </summary>
    /// <param name="provider">The ILogHelperProvider.</param>
    bool AddProvider(ILogHelperProvider provider);

    /// <summary>
    /// add log enricher
    /// </summary>
    /// <param name="enricher">log enricher</param>
    /// <returns></returns>
    bool AddEnricher(ILogHelperLoggingEnricher enricher);

    /// <summary>
    /// Add logs filter
    /// </summary>
    /// <param name="filterFunc">filterFunc, logProviderType/categoryName/Exception, whether to write log</param>
    bool AddFilter(Func<Type, string, LogHelperLogLevel, Exception, bool> filterFunc);

    ///// <summary>
    ///// config period batching
    ///// </summary>
    ///// <param name="period">period</param>
    ///// <param name="batchSize">batchSize</param>
    //void PeriodBatchingConfig(TimeSpan period, int batchSize);

    /// <summary>
    /// Build for LogFactory
    /// </summary>
    /// <returns></returns>
    ILogHelperFactory Build();
}

增加 logging 的配置:

public static class LogHelper
{
    private static ILogHelperFactory LogFactory { get; private set; } = NullLogHelperFactory.Instance;

    public static void ConfigureLogging(Action<ILogHelperLoggingBuilder> configureAction)
    {
        var loggingBuilder = new LogHelperLoggingBuilder();
        configureAction?.Invoke(loggingBuilder);
        LogFactory = loggingBuilder.Build();
    }

    public static ILogHelperLogger GetLogger<T>() => LogFactory.GetLogger(typeof(T));

    public static ILogHelperLogger GetLogger(Type type) => LogFactory.GetLogger(type);

    public static ILogHelperLogger GetLogger(string categoryName)
    {
        return LogFactory.CreateLogger(categoryName);
    }
}

最后的使用方式:

internal class LoggingTest
{
    private static readonly ILogHelperLogger Logger = LogHelper.GetLogger<LoggingTest>();

    public static void MainTest()
    {
        var abc = "1233";
        LogHelper.ConfigureLogging(builder =>
                                   {
                                       builder
                                           .AddLog4Net()
                                           //.AddSerilog(loggerConfig => loggerConfig.WriteTo.Console())
                                           .WithMinimumLevel(LogHelperLogLevel.Info)
                                           .WithFilter((category, level) => level > LogHelperLogLevel.Error && category.StartsWith("System"))
                                           .EnrichWithProperty("Entry0", ApplicationHelper.ApplicationName)
                                           .EnrichWithProperty("Entry1", ApplicationHelper.ApplicationName, e => e.LogLevel >= LogHelperLogLevel.Error)// 当 LogLevel 是 Error 及以上级别时才增加 Property
                                           ;
                                   });

        Logger.Debug("12333 {abc}", abc);
        Logger.Trace("122334334");
        Logger.Info($"122334334 {abc}");

        Logger.Warn("12333, err:{err}", "hahaha");
        Logger.Error("122334334");
        Logger.Fatal("12333");
    }
}

More

增加 LoggingEvent 还想做一个批量提交日志,如上面定义的 PeriodBatchingConfig 一样,批量同步到 Provider 但是实际使用下来,有些 provider 不支持设置日志的时间,时间是内部记录的,这样一来日志记录的时间就不准了,而且大多都不支持批量写日志,所以后面放弃了,但是如果只是用自己的扩展,不用 log4net 之类的外部的日志框架的话,我觉得还是可以做的,可以提高效率,目前主要用 Seriloglog4net,暂时不更新了,就先这样吧

下一版本要解决的事情

  • ILogProvider 记录日志返回一个 Task 感觉有些鸡肋,没太大意义,后面再改一下吧
  • Serilog 的 Filter 是基于 LogEvent 的,后面看是否需要改一下,基于 LogEvent 的话更简洁,而且可以根据 LogEvent 内的 Properties 做过滤,所以 AddFilter 的API 可以更新一下 AddFilter(Func<LogHelperLoggingEvent, bool> filter)

Reference

  • https://github.com/serilog/serilog
  • https://github.com/serilog/serilog-sinks-periodicbatching
  • https://github.com/aspnet/Logging
  • https://github.com/aspnet/Extensions/tree/master/src/Logging
  • https://github.com/WeihanLi/WeihanLi.Common/treehttps://img.qb5200.com/download-x/dev/src/WeihanLi.Common/Logging

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