Question

我使用MappedDiagnosticsLogicalContext，因为我需要数据在异步调用中流动。这是我的NLog.config：

<column name="UserId" layout="${mdlc:item=UserId}" />

但在某些情况下我需要禁用流动，而我不知道该怎么做。例如，我有创建多个线程的代码（请参阅注释）：

void Run()
{
    logger.Info("Starting threads...");  // MappedDiagnosticsLogicalContext.LogicalThreadDictionary is called and ConcurrentDictionary is created

    (new Thread(Func1)).Start();  // both threads will refer to the same ConcurrentDictionary object and share common values, because MappedDiagnosticsLogicalContext stores data in logical call context
    (new Thread(Func2)).Start();
}

void Func1()
{
    MappedDiagnosticsLogicalContext.Set("UserId", "123");
    logger.Info("Some message for Func1");
}

void Func2()
{
    Thread.Sleep(5000);
    logger.Info("Some message for Func2");  // UserId will be added to the log message here (because it was added in other thread), but I don't need it
}

我找到了脏的解决方法：在Func2（）的开头，我打电话给

CallContext.FreeNamedDataSlot("NLog.AsyncableMappedDiagnosticsContext")

因此，当在Func2（）中进行日志记录时，属性MappedDiagnosticsLogicalContext.LogicalThreadDictionary的getter将创建新的ConcurrentDictionary，并且线程将具有单独的字典实例。在MappedDiagnosticsLogicalContext类中使用这样的功能会很好。还是有其他方法可以解决问题吗？

Answer 1

在NLog 4.3中，将添加MappedDiagnosticsLogicalContext.Clear(bool freeDataslot)，请参阅commit。

但在这种情况下使用MDC（而不是MDLC）是不是有意义？

NLog中MappedDiagnosticsLogicalContext的问题

1 个答案: