example_output

{"@source":"tcp://172.28.51.163:4560/client/172.28.51.163:51093","@tags":[],"@fields":{"priority":"INFO","logger_name":"org.jasig.cas.services.DefaultServicesManagerImpl","thread":"scheduler_Worker-9","class":"?","file":"?:?","method":"?"},"@type":"logstash_log4j","@source_host":"172.28.51.163:51093","@source_path":"org.jasig.cas.services.DefaultServicesManagerImpl","@message":"Loaded 0 services.","@timestamp":"2012-12-06T20:00:57.974Z"}

filter workaround

mutate { type => "logstash_log4j" add_tag => [ "jboss", "cas" ] }

gistfile1.txt

input {
  log4j {
    format => "plain"
    host => "172.28.51.163"
    message_format => "string"
    mode => "server"
    port => 4560
    tags => ["jboss","cas"]
    type => "logstash_log4j"
  }
}

filter {
  multiline {
    type => "logstash_log4j"
    pattern => "^\s"
    what => "previous"
  }
}

output {
  stdout { debug => true debug_format => "json"}
  redis { host => "172.28.252.54" data_type => "list" key => "logstash_log4j" }
}