How to access available fields of @metadata in logstash

A sample logstash is running and getting input data from a filebeat running on another machine in the same network. I need to process some metadata of files forwarded by filebeat for example modified date of input file. I found that this information may be available in @metadata variable, and can access some fields like this:

  %{[@metadata][type]}
  %{[@metadata][beat]}

but I don't know how to access all kind of data stored in this field so that i'll be able to extract my own data.

Solution

You can add the following configuration to your logstash.conf file:

output { 
   stdout { 
     codec  => rubydebug {
     metadata => true
    }
  }
}

https://www.elastic.co/blog/logstash-metadata

But this field does not contain metadata of input file