Need to do a calculation in logstash

Elastic Stack Logstash
1

logstash input is elasticsearch and there is field called 'check' in input index.
when ever read the documents in this index need to increment check by 1.

I used ruby filter for this.
ruby{code => "event.set('check',[event.get('check_')].to_i + 1)"}

getting following error
[2019-12-09T18:48:30,925][ERROR][logstash.filters.ruby ] Ruby exception occurred: undefined method `to_i' for ["0"]:Array

2

Remove the square brackets around event.get('check_'). They turn it into an array and prevent .to_i working. Square brackets are used to reference fields in the logstash configuration, not in ruby.

3

thx Badger, it got work.