Hi, 

I'm using im_file module to read windows log file to elasticsearch, and I need to get source file name and some fix string like log type to elastic search as well. I used below configuration, but i couldn't find the FileName in elasticsearch, can someone help? thanks a lot!

<Input TestFileInput>
    Module          im_file
    File              'E:\test\app*.log'
    Exec            $FileName = file_name();
</Input>