Before using the Task Parallel Library, I have often used CorrelationManager.ActivityId to keep track of tracing/error reporting with multiple threads.
ActivityId is stored in Thread Local Storage, so each thread get's its own copy. The idea is that when you fire up a thread (activity), you assign a new ActivityId. The ActivityId will be written to the logs with any other trace information, making it possible to single out the trace information for a single 'Activity'. This is really useful with WCF as the ActivityId can be carried over to the service component.
Here is an example of what I'm talking about:
static void Main(string[] args)
{
ThreadPool.QueueUserWorkItem(new WaitCallback((o) =>
{
DoWork();
}));
}
static void DoWork()
{
try
{
Trace.CorrelationManager.ActivityId = Guid.NewGuid();
//The functions below contain tracing which logs the ActivityID.
CallFunction1();
CallFunction2();
CallFunction3();
}
catch (Exception ex)
{
Trace.Write(Trace.CorrelationManager.ActivityId + " " + ex.ToString());
}
}
Now, with the TPL, my understanding is that multiple Tasks share Threads. Does this mean that ActivityId is prone to being reinitialized mid-task (by another task)? Is there a new mechanism to deal with activity tracing?
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