How to calculate timediff of two fields in the same event

[Ganesh_Venkataraman]

I don't know ruby so found it very difficult. I have used below post to find the solution.

Logstash Ruby filter to subtract difference between two timestamps in single event

I think you could just do something like: ruby { init => "require 'time'" code => "event['time_difference'] = event['received_at'] - event['@timestamp'];" }