C#开发高性能Log Help 类设计开发

概述
项目中要在操作数据库的异常处理中加入写Log日志,对于商业上有要求,写log时对其它操作尽可能影响小,不能因为加入log导致耗时太多.
设计思想
在写入日志时利用Queue来管理,写日志有一个专门的backgroud线程来处理,如果没有日志要写,这个线程处于wait状态,这就有了线程的异步处理.

简单的实现方式
//<summary>
//Write Log
//<summary>
public static void WriteLog(string logFile, string msg)
{
    try
    {
        System.IO.StreamWriter sw = System.IO.File.AppendText(
                logPath + LogFilePrefix +" "+ logFile + " " +
                DateTime.Now.ToString("yyyyMMdd") + ".Log"
            );
        sw.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss: ") + msg);
        sw.Close();
    }
    catch (Exception)
    {

        throw;
    }
}
我们的设计图

而后我们在AddLogMessage时semaphore.Release()就能唤醒wait中的log 线程.
代码设计
/// <summary>
/// Log Help class
/// </summary>
/// <remarks>High performance log class</remarks>
public class Log : IDisposable
{
    //Log Message queue
    private static Queue<LogMessage> _logMessages;

    //log save directory
    private static string _logDirectory;

    //log write file state
    private static bool _state;

    //log type
    private static LogType _logType;

    //log life time sign
    private static DateTime _timeSign;

    //log file stream writer
    private static StreamWriter _writer;

    /// <summary>
    /// Wait enqueue wirte log message semaphore will release
    /// </summary>
    private Semaphore _semaphore;

    /// <summary>
    /// Single instance
    /// </summary>
    private static Log _log;

    /// <summary>
    /// Gets a single instance
    /// </summary>
    public static Log LogInstance
    {
        get { return _log ?? (_log = new Log()); }
    }

    /// <summary>
    /// Initialize Log instance
    /// </summary>
    private void Initialize()
    {
        if (_logMessages == null)
        {   _state = true;
            string logPath = System.Configuration.ConfigurationManager.AppSettings["LogDirectory"];
            _logDirectory = string.IsNullOrEmpty(logPath) ? ".\\log\\" : logPath;
            if (!Directory.Exists(_logDirectory)) Directory.CreateDirectory(_logDirectory);
            _logType = LogType.Daily;
            _semaphore = new Semaphore(0, int.MaxValue, Constants.LogSemaphoreName);
            _logMessages = new Queue<LogMessage>();
            var thread = new Thread(Work) {IsBackground = true};
            thread.Start();
        }
    }

    /// <summary>
    /// Create a log instance
    /// </summary>
    private Log()
    {
        Initialize();
    }

    /// <summary>
    /// Log save name type,default is daily
    /// </summary>
    public LogType LogType
    {
        get { return _logType; }
        set { _logType = value; }
    }

    /// <summary>
    /// Write Log file work method
    /// </summary>
    private void Work()
    {
        while (true)
        {
            //Determine log queue have record need wirte
            if (_logMessages.Count > 0)
            {
                FileWriteMessage();
            }
            else
                if (WaitLogMessage()) break;
        }
    }

    /// <summary>
    /// Write message to log file
    /// </summary>
    private void FileWriteMessage()
    {
        LogMessage logMessage;
        lock (_logMessages)
        {
            logMessage = _logMessages.Dequeue();
        }
        if (logMessage != null)
        {
            FileWrite(logMessage);
        }
    }

    /// <summary>
    /// The thread wait a log message
    /// </summary>

补充：软件开发 , C# ,