Logstash configuration with Google App Engine logs

_etc_logstash_conf.d_central.conf

input {
      file {
        type => "gae"
        path => ["/home/ubuntu/gae_logs/**/*log"]
        tags => ["some","tags"] 
        stat_interval => 30
        discover_interval => 180
      }
}

filter {
  grok {
        match => { "message" => "%{COMMONAPACHELOG} (%{QS:referrer}|-) (%{QS:agent}|-) %{QS:hostname} ms=%{NUMBER:ms} cpu_ms=%{NUMBER:cpu_ms} (cpm_usd=%{NUMBER:cpm_usd}\s)*(loading_request=%{NUMBER:loading_request}\s)*(pending_ms=%{NUMBER:pending_ms}\s)*instance=%{WORD:instance} app_engine_release=(?<app_engine_release>[0-9].[0-9].[0-9]) trace_id=%{WORD:trace_id}" }
  }
  date {
    match => [ "timestamp" , "dd/MMM/yyyy:HH:mm:ss Z" ]
  }
}

output {        
        stdout { codec => rubydebug }
        
      s3 {
        access_key_id => "<access-key>"
        secret_access_key => "<secret-access-key>"
        bucket => "<bucket-name>"
        size_file => 16777216
        time_file => 1
        format => "plain"
        canned_acl => "private"
      } 
}