Logstash仅在我对文件进行手动编辑时读取文件

目前，我有一个将json数组写入json文件的程序。json文件最初为空。我还有一个logstash实例，它运行在下面的配置文件中

input{
 file{
        path => "/Users/CP4/Downloads/gs-accessing-data-mysql-master/complete/example.json"
        codec => "json"
        start_position => "beginning"
        ignore_older => 0

 }
}
filter     {
    mutate   {
            gsub => [ "message","\[",""]
            gsub => [ "message","\n",""]
            gsub => [ "event","\},\{",","]
        }
    json { source => message }
}

output{
    elasticsearch{
        hosts => "localhost:9200"
        index => "test123"
    }
    stdout { codec => rubydebug }
}

出于某种原因，logstash只会在我进入并手动进行一些更改后读取该文件，而不是在我的程序向其写入json时读取。这可能是什么原因造成的？配置文件的设置方式是否错误？谢谢