我有一个 windows TCP 服务，有很多设备连接到它，一个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。

所以像这样:

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

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

现在我还没有使用像 log4net 或 NLog 这样的第 3 方库，我有一个类可以处理这个问题。

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，一些线程试图同时访问同一个日志文件导致抛出异常。

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？

编辑

记录器类的变化

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;
    }
}

最佳答案

如果您不想使用现有的解决方案，在记录器中处理多线程写入的合理方法是使用队列。这是一个草图:

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; }
}

然后在您的记录器类中:

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(delegate)给单独的类，一个一个地写入日志消息，因此不会有任何多线程问题。这种方法的另一个好处是日志记录是异步发生的，因此不会减慢实际工作。

缺点是在进程崩溃的情况下你可能会丢失一些消息(不要认为这真的是个问题但还是要提一下)并且你使用单独的线程来异步记录。当只有一个线程时，这不是问题，但如果您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，除非您真的每秒写入大量消息)。

关于c# - 每个客户端和日期的单独日志文件和目录，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36842836/