logstash配置文件时出错，挺急的。

这个是我的配置input 和 output 忽略

filter {
grok {
match=> { "message" => "%{DATESTAMP:timestamp}%{LOGLEVEL:level} %{GREEDYDATA:syslog_message}" }
add_tag => [ "message", "(\d+)\.(\d+)\.(\d+)\.(\d+)" ]
drop_if_match => true
}
date {
match=> [ "timestamp","dd/MM/yy:HH:mm:ss Z" ]
}
}
提示错误
Unknown setting 'drop_if_match' for grok {:level=>:error}
Error: Something is wrong with your configuration.
You may be interested in the '--configtest' flag which you can
use to validate logstash's configuration before you choose
to restart a running system.

包括使用add_field 和drop参数时都是报这个错误