[开源]基于Log4Net简单实现KafkaAppender

背景

1. 基于之前基于Log4Net本地日志服务简单实现 实现本地日志服务，但是随着项目开发演进，本地日志服务满足不了需求，譬如在预发布环境或者生产环境，不可能让开发人员登录查看本地日志文件分析。
2. Kafka+ELK日志服务套件，可以在线日志服务可以解决上述问题，并且提供丰富报表分析等等；
3. 具体源码：MasterChief
4. Nuget：Install-Package MasterChief.DotNet.Core.KafkaLog
5. 欢迎Star，欢迎Issues；

源码

1. 基于Log4Net来实现与kafka通讯Appender

    public class KafkaAppender : AppenderSkeleton
    {
        #region Fields
   
        /// <summary>
        ///     Kafka 生产者
        /// </summary>
        private Producer _kafkaProducer;
   
        #endregion Fields
   
        #region Properties
   
        /// <summary>
        ///     Brokers
        /// </summary>
        public string Brokers { get; set; }
   
        /// <summary>
        ///     Topic
        /// </summary>
        public string Topic { get; set; }
   
        #endregion Properties
   
        #region Methods
   
        /// <summary>
        ///     Initialize the appender based on the options set
        /// </summary>
        /// <remarks>
        ///     <para>
        ///         This is part of the <see cref="T:log4net.Core.IOptionHandler" /> delayed object
        ///         activation scheme. The <see cref="M:log4net.Appender.AppenderSkeleton.ActivateOptions" /> method must
        ///         be called on this object after the configuration properties have
        ///         been set. Until <see cref="M:log4net.Appender.AppenderSkeleton.ActivateOptions" /> is called this
        ///         object is in an undefined state and must not be used.
        ///     </para>
        ///     <para>
        ///         If any of the configuration properties are modified then
        ///         <see cref="M:log4net.Appender.AppenderSkeleton.ActivateOptions" /> must be called again.
        ///     </para>
        /// </remarks>
        public override void ActivateOptions()
        {
            base.ActivateOptions();
            InitKafkaProducer();
        }
   
        /// <summary>
        ///     Subclasses of <see cref="T:log4net.Appender.AppenderSkeleton" /> should implement this method
        ///     to perform actual logging.
        /// </summary>
        /// <param name="loggingEvent">The event to append.</param>
        /// <remarks>
        ///     <para>
        ///         A subclass must implement this method to perform
        ///         logging of the <paramref name="loggingEvent" />.
        ///     </para>
        ///     <para>
        ///         This method will be called by <see cref="M:DoAppend(LoggingEvent)" />
        ///         if all the conditions listed for that method are met.
        ///     </para>
        ///     <para>
        ///         To restrict the logging of events in the appender
        ///         override the <see cref="M:PreAppendCheck()" /> method.
        ///     </para>
        /// </remarks>
        protected override void Append(LoggingEvent loggingEvent)
        {
            try
            {
                var message = GetLogMessage(loggingEvent);
                var topic = GetTopic(loggingEvent);
   
                _ = _kafkaProducer.SendMessageAsync(topic, new[] {new Message(message)});
            }
            catch (Exception ex)
            {
                ErrorHandler.Error("KafkaProducer SendMessageAsync", ex);
            }
        }
   
        /// <summary>
        ///     Raises the Close event.
        /// </summary>
        /// <remarks>
        ///     <para>
        ///         Releases any resources allocated within the appender such as file handles,
        ///         network connections, etc.
        ///     </para>
        ///     <para>
        ///         It is a programming error to append to a closed appender.
        ///     </para>
        /// </remarks>
        protected override void OnClose()
        {
            base.OnClose();
            StopKafkaProducer();
        }
   
        private string GetLogMessage(LoggingEvent loggingEvent)
        {
            var builder = new StringBuilder();
            using (var writer = new StringWriter(builder))
            {
                Layout.Format(writer, loggingEvent);
   
                if (Layout.IgnoresException && loggingEvent.ExceptionObject != null)
                    writer.Write(loggingEvent.GetExceptionString());
   
                return writer.ToString();
            }
        }
   
        private string GetTopic(LoggingEvent loggingEvent)
        {
            return string.IsNullOrEmpty(Topic) ? Path.GetFileNameWithoutExtension(loggingEvent.Domain) : Topic;
        }
   
        /// <summary>
        ///     初始化Kafka 生产者
        /// </summary>
        private void InitKafkaProducer()
        {
            try
            {
                if (string.IsNullOrEmpty(Brokers)) Brokers = "http://localhost:9200";
   
                if (_kafkaProducer == null)
                {
                    var brokers = new Uri(Brokers);
                    var kafkaOptions = new KafkaOptions(brokers)
                    {
                        Log = new KafkaLog()
                    };
                    _kafkaProducer = new Producer(new BrokerRouter(kafkaOptions));
                }
            }
            catch (Exception ex)
            {
                ErrorHandler.Error("InitKafkaProducer", ex);
            }
        }
   
        /// <summary>
        ///     停止生产者
        /// </summary>
        private void StopKafkaProducer()
        {
            try
            {
                _kafkaProducer?.Stop();
            }
            catch (Exception ex)
            {
                ErrorHandler.Error("StopKafkaProducer", ex);
            }
        }
   
        #endregion Methods
    }
   
   

2. 基于之前定义接口，来实现kafkaLogService

   public sealed class KafkaLogService : ILogService
   {
       #region Constructors
   
       /// <summary>
       ///     Initializes the <see cref="FileLogService" /> class.
       /// </summary>
       static KafkaLogService()
       {
           KafkaLogger = LogManager.GetLogger(KafkaLoggerName);
       }
   
       #endregion Constructors
   
       #region Fields
   
       /// <summary>
       ///     Kafka logger name
       /// </summary>
       public const string KafkaLoggerName = "KafkaLogger";
   
       /// <summary>
       ///     Kafka logger
       /// </summary>
       public static readonly ILog KafkaLogger;
   
       #endregion Fields
   
       #region Methods
   
       /// <summary>
       ///     Debug记录
       /// </summary>
       /// <param name="message">日志信息</param>
       public void Debug(string message)
       {
           if (KafkaLogger.IsDebugEnabled) KafkaLogger.Debug(message);
       }
   
       /// <summary>
       ///     Debug记录
       /// </summary>
       /// <param name="message">日志信息</param>
       /// <param name="ex">异常信息</param>
       public void Debug(string message, Exception ex)
       {
           if (KafkaLogger.IsDebugEnabled) KafkaLogger.Debug(message, ex);
       }
   
       /// <summary>
       ///     Error记录
       /// </summary>
       /// <param name="message">日志信息</param>
       public void Error(string message)
       {
           if (KafkaLogger.IsErrorEnabled) KafkaLogger.Error(message);
       }
   
       /// <summary>
       ///     Error记录
       /// </summary>
       /// <param name="message">日志信息</param>
       /// <param name="ex">异常信息</param>
       public void Error(string message, Exception ex)
       {
           if (KafkaLogger.IsErrorEnabled) KafkaLogger.Error(message, ex);
       }
   
       /// <summary>
       ///     Fatal记录
       /// </summary>
       /// <param name="message">日志信息</param>
       public void Fatal(string message)
       {
           if (KafkaLogger.IsFatalEnabled) KafkaLogger.Fatal(message);
       }
   
       /// <summary>
       ///     Fatal记录
       /// </summary>
       /// <param name="message">日志信息</param>
       /// <param name="ex">异常信息</param>
       public void Fatal(string message, Exception ex)
       {
           if (KafkaLogger.IsFatalEnabled) KafkaLogger.Fatal(message, ex);
       }
   
       /// <summary>
       ///     Info记录
       /// </summary>
       /// <param name="message">日志信息</param>
       public void Info(string message)
       {
           if (KafkaLogger.IsInfoEnabled) KafkaLogger.Info(message);
       }
   
       /// <summary>
       ///     Info记录
       /// </summary>
       /// <param name="message">日志信息</param>
       /// <param name="ex">异常信息</param>
       public void Info(string message, Exception ex)
       {
           if (KafkaLogger.IsInfoEnabled) KafkaLogger.Info(message, ex);
       }
   
       /// <summary>
       ///     Warn记录
       /// </summary>
       /// <param name="message">日志信息</param>
       public void Warn(string message)
       {
           if (KafkaLogger.IsWarnEnabled) KafkaLogger.Warn(message);
       }
   
       /// <summary>
       ///     Warn记录
       /// </summary>
       /// <param name="message">日志信息</param>
       /// <param name="ex">异常信息</param>
       public void Warn(string message, Exception ex)
       {
           if (KafkaLogger.IsWarnEnabled) KafkaLogger.Warn(message, ex);
       }
   
       #endregion Methods
   }
   

3. 修改Log4Net.Config，定义Kafka的Topic以及Brokers

       <appender name="KafkaAppender" type="MasterChief.DotNet.Core.KafkaLog.KafkaAppender, MasterChief.DotNet.Core.KafkaLog">
           <param name="Topic" value="beats" />
           <param name="Brokers" value="http://localhost:9092" />
           <layout type="log4net.Layout.PatternLayout">
               <conversionPattern value="发生时间：%date %newline事件级别：%-5level %newline事件来源：%logger%newline日志内容：%message%newline" />
           </layout>
       </appender>
   

使用

1. 由于基于上篇说的日志接口，所以可以通过Ioc切换，而且不影响在业务代码调用；
2. 基于业务需求，您可以同时落地本地日志，保证网络抖动或者不正常的时候能够正常记录日志；

结语

1. 小弟不才，大佬轻拍；