kibana 4 - Logstash:Filter configuration for multiline log -

i trying parse multi line log using logstash. log looks below

   ==> /var/log/mail/log/alerting.log <==      2016/01/30 08:40:29 , worker_1 ,       {u'name': u'high', u'type': u'alert', u'alertid': 1122, u'queue_in_time': u'2016-01-30 08:40:29', u'path': u'/var/log/mail/log/alert.log'} 

but not sure how set configuration file. config file looks :

    input {       file {         path => "/logs/var/alerts.log"         type => "queue"         start_position => "beginning"         codec =>multiline{                     pattern => "==>"                     negate => true                     => previous } } } filter {      if [type] == 'application'{             date {         match => [ "timestamp" , "yyyy/mm/dd hh:mm:ss" ]                      }         }     }      output {       stdout { }     } 

can tell me how configure filter kind of logs ? new elk stack , not able understand how configure config file parsing custom logs.