10-syslog.conf

filter {

    if "Ready" not in [tags] {
      mutate {
        add_tag => [ "syslog" ]
      }
    }
  }
}

filter {
  if [type] == "syslog" {
    mutate {
      remove_tag => "Ready"
    }
  }
}

filter {
  if "syslog" in [tags] {
    grok {
      match => { "message" => "%{SYSLOGTIMESTAMP:syslog_timestamp} %{SYSLOGHOST:syslog_hostname} %{DATA:syslog_program}(?:\[%{POSINT:syslog_pid}\])?: %{GREEDYDATA:syslog_message}" }
      add_field => [ "received_at", "%{@timestamp}" ]
      add_field => [ "received_from", "%{host}" ]
    }
    syslog_pri { }
    date {
      match => [ "syslog_timestamp", "MMM  d HH:mm:ss", "MMM  dd HH:mm:ss" ]
      locale => "en"
    }

    if !("_grokparsefailure" in [tags]) {
      mutate {
        replace => [ "@source_host", "%{syslog_hostname}" ]
        replace => [ "@message", "%{syslog_message}" ]
      }
    }

    mutate {
      remove_field => [ "syslog_hostname", "syslog_message", "syslog_timestamp" ]
    }
#    if "_grokparsefailure" in [tags] {
#      drop { }
#    }
  }
}