Ruby filter - How to add fields?

Elastic Stack Logstash
1

Hi

I'm trying to do this:

if [directive] {
	
		ruby {
	
			code => 
				"if event['directive'] <=30
					event[scenario] = 'scenario_one'
				 end
				 "
			
		}
	}

Basically if the directive field exists (which I have already converted to an integer) then I want to test its value against several conditionals then depending on where the value falls I need to add a new field "scenario" with the scenario name Eg "scenario_one".

Can't seem to get Logstash to co-operate as it is complaining about undefined field "scenario".

I would appreciate any advice. Thanks.

SOLVED

I forgot to wrap the new field name in single quotes!!

This worked:

event['scenario'] = 'scenario_one'

Awesome... the ruby filter is so powerful!