How to calculate timestamp difference in logstash config file?

[Rahul_Chougule]

I have two timestamp fields: submit_date("MM/dd/YYYY HH:mm") and completed date("MM/dd/YYYY HH:mm").
I want to calculate time difference between these two fields and wanted to add it as a new field while ingesting data in Elasticsearch.

any help will be appreciated.
Thank you.

[Badger]

Parse them both using date filters, then use ruby to calculate the difference. Something like this.