Telegraf Tail Plug-in, recursive files option doesn't work

Using ** in the “files” option of a Tail config file doesn’t seem to work, as advertised here:

These accept standard unix glob matching rules, but with the addition of

** as a “super asterisk”. ie:

“/var/log/**.log” -> recursively find all .log files in /var/log

“/var/log//.log” -> find all .log files with a parent dir in /var/log

When I have this in the config file:
files = ["/one/two/three/four/**.txt"]
(using .txt not .log)
then I get no data in InfluxDB, and something is making my app slow.

When I have this in the config file:
files = ["/one/two/three/four/*.txt"]
then everything is fine.

It seems to work for me using this config:

  files = ["/var/log/**.log"]
  from_beginning = true
  data_format = "value"
  data_type = "string"

But I can imagine if you have lots of logs or are using a slower data_format (like grok"), that this could be quite expensive. It will also help if you turn off from_beginning so that all prior log messages won’t be collected.