Question

我有一个Windows TCP服务，它有许多连接到它的设备，而客户端可以有一个或多个设备。

要求：

每个客户端的单独文件夹，每个设备都有单独的日志文件。

这样的事情：

/MyService/25-04-2016/
    Client 1/
        Device1.txt 
        Device2.txt 
        Device3.txt 

    Client 2/
        Device1.txt 
        Device2.txt 
        Device3.txt

现在我没有使用像log4net或NLog这样的第三方库，我有一个处理此问题的类。

public class xPTLogger : IDisposable
{
    private static object fileLocker = new object();

    private readonly string _logFileName;
    private readonly string _logFilesLocation;
    private readonly int _clientId;

    public xPTLogger() : this("General") { }

    public xPTLogger(string logFileName)
    {
        _clientId = -1;
        _logFileName = logFileName;
        _logFilesLocation = SharedConstants.LogFilesLocation; // D:/LogFiles/
    }

    public xPTLogger(string logFileName, int companyId)
    {
        _clientId = companyId;
        _logFileName = logFileName;
        _logFilesLocation = SharedConstants.LogFilesLocation;
    }

    public void LogMessage(MessageType messageType, string message)
    {
        LogMessage(messageType, message, _logFileName);
    }

    public void LogExceptionMessage(string message, Exception innerException, string stackTrace)
    {
        var exceptionMessage = innerException != null
                ? string.Format("Exception: [{0}], Inner: [{1}], Stack Trace: [{2}]", message, innerException.Message, stackTrace)
                : string.Format("Exception: [{0}], Stack Trace: [{1}]", message, stackTrace);

        LogMessage(MessageType.Error, exceptionMessage, "Exceptions");
    }

    public void LogMessage(MessageType messageType, string message, string logFileName)
    {
        var dateTime = DateTime.UtcNow.ToString("dd-MMM-yyyy");

        var logFilesLocation = string.Format("{0}{1}\\", _logFilesLocation, dateTime);

        if (_clientId > -1) { logFilesLocation = string.Format("{0}{1}\\{2}\\", _logFilesLocation, dateTime, _clientId); }


        var fullLogFile = string.IsNullOrEmpty(logFileName) ? "GeneralLog.txt" : string.Format("{0}.txt", logFileName);


        var msg = string.Format("{0} | {1} | {2}\r\n", DateTime.UtcNow.ToString("dd-MMM-yyyy HH:mm:ss"), messageType, message);

        fullLogFile = GenerateLogFilePath(logFilesLocation, fullLogFile);

        LogToFile(fullLogFile, msg);
    }

    private string GenerateLogFilePath(string objectLogDirectory, string objectLogFileName)
    {
        if (string.IsNullOrEmpty(objectLogDirectory))
            throw new ArgumentNullException(string.Format("{0} location cannot be null or empty", "objectLogDirectory"));
        if (string.IsNullOrEmpty(objectLogFileName))
            throw new ArgumentNullException(string.Format("{0} cannot be null or empty", "objectLogFileName"));

        if (!Directory.Exists(objectLogDirectory))
            Directory.CreateDirectory(objectLogDirectory);
        string logFilePath = string.Format("{0}\\{1}", objectLogDirectory, objectLogFileName);
        return logFilePath;
    }

    private void LogToFile(string logFilePath, string message)
    {
        if (!File.Exists(logFilePath))
        {
            File.WriteAllText(logFilePath, message);
        }
        else
        {
            lock (fileLocker)
            {
                File.AppendAllText(logFilePath, message);
            }
        }
    }

    public void Dispose()
    {
        fileLocker = new object();
    }
}

然后我可以像这样使用它：

 var _logger = new xPTLogger("DeviceId", 12);

 _logger.LogMessage(MessageType.Info, string.Format("Information Message = [{0}]", 1));

上述类的问题在于，由于服务是多线程的，因此某些线程会尝试同时访问同一个日志文件，从而导致抛出异常。

25-Apr-2016 13:07:00 | Error | Exception: The process cannot access the file 'D:\LogFiles\25-Apr-2016\0\LogFile.txt' because it is being used by another process.

这有时会导致我的服务崩溃。

如何让我的Logger类在多线程服务中工作？

修改

记录器类的更改

public class xPTLogger : IDisposable
{
    private object fileLocker = new object();

    private readonly string _logFileName;
    private readonly string _logFilesLocation;
    private readonly int _companyId;

    public xPTLogger() : this("General") { }

    public xPTLogger(string logFileName)
    {
        _companyId = -1;
        _logFileName = logFileName;
        _logFilesLocation = SharedConstants.LogFilesLocation; // "D:\\MyLogs";
    }

    public xPTLogger(string logFileName, int companyId)
    {
        _companyId = companyId;
        _logFileName = logFileName;
        _logFilesLocation = SharedConstants.LogFilesLocation;
    }

    public void LogMessage(MessageType messageType, string message)
    {
        LogMessage(messageType, message, _logFileName);
    }

    public void LogExceptionMessage(string message, Exception innerException, string stackTrace)
    {
        var exceptionMessage = innerException != null
                ? string.Format("Exception: [{0}], Inner: [{1}], Stack Trace: [{2}]", message, innerException.Message, stackTrace)
                : string.Format("Exception: [{0}], Stack Trace: [{1}]", message, stackTrace);

        LogMessage(MessageType.Error, exceptionMessage, "Exceptions");
    }

    public void LogMessage(MessageType messageType, string message, string logFileName)
    {
        if (messageType == MessageType.Debug)
        {
            if (!SharedConstants.EnableDebugLog)
                return;
        }

        var dateTime = DateTime.UtcNow.ToString("dd-MMM-yyyy");

        var logFilesLocation = string.Format("{0}{1}\\", _logFilesLocation, dateTime);

        if (_companyId > -1) { logFilesLocation = string.Format("{0}{1}\\{2}\\", _logFilesLocation, dateTime, _companyId); }


        var fullLogFile = string.IsNullOrEmpty(logFileName) ? "GeneralLog.txt" : string.Format("{0}.txt", logFileName);


        var msg = string.Format("{0} | {1} | {2}\r\n", DateTime.UtcNow.ToString("dd-MMM-yyyy HH:mm:ss"), messageType, message);

        fullLogFile = GenerateLogFilePath(logFilesLocation, fullLogFile);

        LogToFile(fullLogFile, msg);
    }

    private string GenerateLogFilePath(string objectLogDirectory, string objectLogFileName)
    {
        if (string.IsNullOrEmpty(objectLogDirectory))
            throw new ArgumentNullException(string.Format("{0} location cannot be null or empty", "objectLogDirectory"));
        if (string.IsNullOrEmpty(objectLogFileName))
            throw new ArgumentNullException(string.Format("{0} cannot be null or empty", "objectLogFileName"));

        if (!Directory.Exists(objectLogDirectory))
            Directory.CreateDirectory(objectLogDirectory);
        string logFilePath = string.Format("{0}\\{1}", objectLogDirectory, objectLogFileName);
        return logFilePath;
    }

    private void LogToFile(string logFilePath, string message)
    {
        lock (fileLocker)
        {
            try
            {
                if (!File.Exists(logFilePath))
                {
                    File.WriteAllText(logFilePath, message);
                }
                else
                {
                    File.AppendAllText(logFilePath, message);
                }
            }
            catch (Exception ex)
            {
                var exceptionMessage = ex.InnerException != null
                                ? string.Format("Exception: [{0}], Inner: [{1}], Stack Trace: [{2}]", ex.Message, ex.InnerException.Message, ex.StackTrace)
                                : string.Format("Exception: [{0}], Stack Trace: [{1}]", ex.Message, ex.StackTrace);

                var logFilesLocation = string.Format("{0}{1}\\", _logFilesLocation, DateTime.UtcNow.ToString("dd-MMM-yyyy"));

                var logFile = GenerateLogFilePath(logFilesLocation, "FileAccessExceptions.txt");

                try
                {
                    if (!File.Exists(logFile))
                    {
                        File.WriteAllText(logFile, exceptionMessage);
                    }
                    else
                    {
                        File.AppendAllText(logFile, exceptionMessage);
                    }
                }
                catch (Exception) { }
            }

        }
    }

    public void Dispose()
    {
        //fileLocker = new object();
        //_logFileName = null;
        //_logFilesLocation = null;
        //_companyId = null;
    }
}

Answer 1

如果您不想使用现有解决方案，则在记录器中处理多线程写入的合理方法是使用队列。这是一幅草图：

public class LogQueue : IDisposable {
    private static readonly Lazy<LogQueue> _isntance = new Lazy<LogQueue>(CreateInstance, true);
    private Thread _thread;
    private readonly BlockingCollection<LogItem> _queue = new BlockingCollection<LogItem>(new ConcurrentQueue<LogItem>());

    private static LogQueue CreateInstance() {
        var queue = new LogQueue();
        queue.Start();
        return queue;
    }

    public static LogQueue Instance => _isntance.Value;

    public void QueueItem(LogItem item) {
        _queue.Add(item);
    }

    public void Dispose() {
        _queue.CompleteAdding();
        // wait here until all pending messages are written
        _thread.Join();
    }

    private void Start() {
        _thread = new Thread(ConsumeQueue) {
            IsBackground = true
        };
        _thread.Start();
    }

    private void ConsumeQueue() {
        foreach (var item in _queue.GetConsumingEnumerable()) {
            try {
                // append to your item.TargetFile here                    
            }
            catch (Exception ex) {
                // do something or ignore
            }
        }
    }
}

public class LogItem {
    public string TargetFile { get; set; }
    public string Message { get; set; }
    public MessageType MessageType { get; set; }
}

然后在你的记录器类中：

private void LogToFile(string logFilePath, string message) {
    LogQueue.Instance.QueueItem(new LogItem() {
        TargetFile = logFilePath,
        Message = message
    });
}

这里我们将实际的日志记录委托给单独的类，它逐个写入日志消息，因此不会出现任何多线程问题。这种方法的另一个好处是日志记录异步发生，因此不会减慢实际工作。

缺点是你可以在进程崩溃的情况下丢失一些消息（不要认为这确实是一个问题但仍然提到它）并且你使用单独的线程来异步记录。当有一个线程时，这不是问题，但是如果你为每个设备创建一个线程，那可能是（尽管没有必要 - 只需使用单个队列，除非你真的每秒写了很多消息）。

Answer 2

虽然它可能不是最优雅的解决方案，但您可以内置重试逻辑。例如：

int retries = 0;
while(retries <= 3){
    try{
        var _logger = new xPTLogger("DeviceId", 12);

        _logger.LogMessage(MessageType.Info, string.Format("Information Message = [{0}]", 1));
        break;
    }
    catch (Exception ex){
        //Console.WriteLine(ex.Message);
        retries++;
    }
}

另外，我刚刚编写了这段代码而没有实际测试它，所以如果它有一些愚蠢的错误，请原谅我。但很简单，它会尝试写入日志，就像你在＆＃34;中设置的那样多次。线。如果你觉得它值得，你甚至可以在catch块中添加一个sleep语句。

我没有使用Log4Net或NLog的经验，所以没有评论。也许通过其中一个软件包可以获得甜蜜的解决方案。祝你好运！

为每个客户端和日期分隔日志文件和目录

2 个答案: