trying for a logstash conf file that works with java's logback logger

logback.conf

input {
  # file {
  #   path => ["/var/log/knewton/*/*.log"]
  #   type => "knewton_logback"
  # }
  stdin {
    type => "knewton_logback"
  }
}

filter {
  # Logback logs junk like this:
  # 2012-05-23 15:07:28,876 WARN  [PZDiscoveryMonitor STARTING] c.k.p.d.PZDiscoveryMonitor    : Failed to load fileConfig
  # com.knewton.knewtonconfig.exception.NotFoundException: java.io.FileNotFoundException: /etc/knewton/discovery/grover/platform.yml (No such file or directory)
  # 	at com.knewton.knewtonconfig.configuration.FileInputStreamProvider.get(FileInputStreamProvider.java:30) ~[KPIP.jar:na]
  # 	at com.knewton.knewtonconfig.discovery.StreamDiscoveryProvider.get(StreamDiscoveryProvider.java:116) ~[KPIP.jar:na]
  # 	at com.knewton.knewtonconfig.discovery.StreamDiscoveryProvider.get(StreamDiscoveryProvider.java:49) ~[KPIP.jar:na]
  # 	at com.knewton.pettingzoo.discovery.PZDiscoveryMonitor.startUp(PZDiscoveryMonitor.java:245) ~[KPIP.jar:na]
  # 	at com.google.common.util.concurrent.AbstractIdleService$1$1.run(AbstractIdleService.java:43) [KPIP.jar:na]
  # 	at java.lang.Thread.run(Thread.java:679) [na:1.6.0_22]
  # Caused by: java.io.FileNotFoundException: /etc/knewton/discovery/grover/platform.yml (No such file or directory)
  # 	at java.io.FileInputStream.open(Native Method) ~[na:1.6.0_22]
  # 	at java.io.FileInputStream.<init>(FileInputStream.java:137) ~[na:1.6.0_22]
  # 	at java.io.FileInputStream.<init>(FileInputStream.java:96) ~[na:1.6.0_22]
  # 	at com.knewton.knewtonconfig.configuration.FileInputStreamProvider.get(FileInputStreamProvider.java:28) ~[KPIP.jar:na]
  # 	... 5 common frames omitted
  date {
    type => "knewton_logback"
    timestamp => "yyyy-MM-dd hh:mm:ss,SSS"
  }

  multiline {
    type => "knewton_logback"
    pattern => "^(\\s+|com|Caused)"
    what => "previous"
  }

  # Returns the wrong level
  # gelfify {
  #   type => "knewton_logback"
  # }

  grok {
    type => "knewton_logback"
    patterns_path => "/usr/local/share/grok/patterns"
    pattern => ["%{JAVALOGBACK}"]
  }
  mutate {
    type => "knewton_logback"
    add_field => ["level", "%{severity}"]
  }

}

output {
  gelf {
    host => "graylog2.utility.knewton.net"
    sender => "KPIP"
    level => "info"
    facility => "KPIP"
  }
  #  stdout {
  #    debug => true
  #    debug_format => json
  #    type => "knewton_logback"
  #  }  
}

patterns-java

JAVACLASS (?:[a-z-]+\.)[A-Za-z0-9]+
JAVAFILE (?:[A-Za-z0-9_.-]})
JAVASTACKTRACEPART "at %{JAVACLASS:class}\.%{WORD:method}\(%{JAVAFILE:file}:%{NUMBER:line}\)
MILLISECOND (\d{3})
JAVALOGBACKTIMESTAMP %{YEAR}-%{MONTHNUM}-%{MONTHDAY}[T ]%{HOUR}:?%{MINUTE}(?::?%{SECOND}),%{MILLISECOND}
JAVALOGBACK %{JAVALOGBACKTIMESTAMP:timestamp} (?:%{WORD:severity})