Logstash filter duration calculation

Elastic Stack Logstash
3

I did that using

 ruby {
        code => "event['recording_duration'] = (event['recording_end_timed'] - event['recording_start_timed'])"
        code => "if event['recording_duration'] < 0 then event['recording_duration'] = event['recording_duration'] + 86400 end"

}
and ruby plugin gave me an error stating it was expecting a string.

then I separated them and it worked:

 ruby {
        code => "event['recording_duration'] = (event['recording_end_timed'] - event['recording_start_timed'])"
 }
 ruby {
       code => "if event['recording_duration'] < 0 then event['recording_duration'] = event['recording_duration'] + 86400 end"
 }