Logstash filter

gistfile1.txt

{"host": "examople.com", "remote_addr": "A.B.C.D", "remote_user": "-", "time_local":"04/Dec/2013:21:05:47 +0000", "request": "GET XXXXXX HTTP/1.1", "status":200, "body_bytes_sent": 47322, "http_referer": "http://logstash.net", "http_user_agent": "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko", "upstream": {"cache_status":"-", "status": [200], "response_time":[0.302], "addr":"A.B.C.D:80" }, "postdata": {"request_body": "-", "request_length":2963, "request_completion":"OK" },"cookie": {"userid": "-41813428", "param2": "YZY" } }


 35   if [cookie.userid] >= 0 {
 36     mutate { add_field => ['btng_user_logged', 1] }
 37   } else {
 38     mutate { add_field => ['btng_user_logged', 0] }
 39   }
 
 
 Exception in filterworker {"exception"=>#<NoMethodError: undefined method `>=' for nil:NilClass>, "backtrace"=>["(eval):113:in `initialize'", "org/jruby/RubyProc.java:271:in `call'", "file:/opt/logstash/server/lib/logstash-1.2.2.jar!/logstash/pipeline.rb:250:in `filter'", "file:/opt/logstash/server/lib/logstash-1.2.2.jar!/logstash/pipeline.rb:191:in `filterworker'", "file:/opt/logstash/server/lib/logstash-1.2.2.jar!/logstash/pipeline.rb:134:in `start_filters'"], :level=>:error, :file=>"/opt/logstash/server/lib/logstash-1.2.2.jar!/logstash/pipeline.rb", :line=>"200"}