Logstash configuration for filtering trac logs

logstash_trac.conf

filter {

   grok {
      type => "trac"
      match => [ "message", "%{DATE-US} %{TIME},%{INT} Trac.%{WORD}. %{WORD:level}: %{GREEDYDATA:text}" ]
   }

   multiline {
      type => "trac"
      pattern => "%{DATE-US} %{TIME},%{INT} Trac.%{WORD}. ERROR: %{GREEDYDATA:text}"
      what => "next"
   }

   multiline {
      type => "trac"
      pattern => "%{DATE-US} %{TIME},%{INT} Trac.%{WORD}. %{WORD:level}: %{GREEDYDATA:text}"
      negate => true
      what => "previous"
   }
}