Question about fingerprint and de-duplicating

I have in my setup properly setup de-duplication based on fingerprinting messages. I had a question to the community as in is there a way to count the number of duplicates and store it as a field which increments every time a duplicate of a type is seen. Any leads on this will be great ...

thanks

http://logstash.net/docs/1.4.2/filters/metrics may do what you want.

Would you put your config here? I am interested in doing this but cannot find a good end to end document on how to do it.