TPL Dataflow log item if send to ITargetblock

Question

I'm actually facing a problem with TPL dataflow (it seems that an item is added twice). Therefore I wanted to know if there is the option to inject a callback, which I can use for logging, if an item is posted to a target block. I checked the ActionBlock, BufferBlock constructors, and also the LinkTo methods but didn't find anything.

Any hints?

Answer 1

No, as the TPL Dataflow is quite lightweight library, you need to do a decorator block instead, or use some logging buffer, like TransformBlock which basically just logs the message, something like this:

var loggingTransform = new TransformBlock<TIn, TOut>(m => 
{
    Logger.Info(m);
    return m;
});

Some useful links:

• Guide to Implementing Custom TPLDataflow Blocks
• Walkthrough: Creating a Custom Dataflow Block Type