Can't make the "aggregate" filter to work

Elastic Stack Logstash
1

Hi there,

I'd like to use aggregate filter to gather informations from different log lines, but I'm not able to make it write anything in the logs.

I tried to add the following lines in my logstash configuration :

filter {
    aggregate { task_id=>"test" code=>"event['test']='OK'" }
}

but the test field is not added in my logs.
According to the documentation this should work that way, right ?

Thanks for your help

(Note : I use logstash v 2.0)