（Logstash）使用日志中的时间戳设置@timestamp值

Question

我需要将日志的时间戳记用作@timestamp。我尝试了与互联网不同的方法，但在我的情况下却没有奏效

input {
    s3 {
        bucket => "*"
        access_key_id => "*"
        secret_access_key => "*"
        prefix => "*"
        backup_to_bucket => "*"
        backup_add_prefix => "*"
        region => "*"
        delete => *
    }
}

filter {
    grok {
        match => { "message" => "%{IPORHOST:clientip} \[%{TIMESTAMP_ISO8601:logtimestamp}\] %{WORD:protocol} %{GREEDYDATA:uri_path} \"%{WORD:verb} %{DATA:partial_request} HTTP/%{NUMBER:httpversion}\" \"%{GREEDYDATA:User_Agent}\" \"%{GREEDYDATA:request}\" %{NUMBER:response} %{NUMBER:ret1} %{NUMBER:ret2} "}
    }



date {
    match => ["logtimestamp", "ISO8601"]
    target => "@timestamp"
  }

mutate
    {
         remove_field => [ "message" ]
    }
}
output {
    elasticsearch {
        hosts => ["endpoint:9200"]
        index => "mywebsite.com"
    }
    stdout {
        codec => rubydebug
    }

}

示例日志条目：

46.229.168.134 [17/Jun/2019:08:00:19 +0000] https www.mywebsite.com "GET /somefolder/somefolder/request HTTP/1.1" "Mozilla/5.0 (compatible; someBot/3~bl; +http://www.somebot.com/bot.html)" "" 200 48260 8  

它没有显示任何错误，但是@timestamp与日志的时间戳不同，即使我尝试将其转换为浏览器的时区（即配置kibana的方式）。