Creating new field with logstash

I invite you to fix your grok configuration :

grok{
  match => {"message" => ["job_id=%{NOTSPACE:job_id},description=%{DATA:description},result= 
%{GREEDYDATA:result}"]
}

If in Kibana, you aim to have a field named JobID, you can directly name your field JobID in grok expression :

grok{
  match => {"message" => ["job_id=%{NOTSPACE:JobID},description=%{DATA:description},result= 
%{GREEDYDATA:result}"]
}