MACHINE_FQDN_VALUE=bla.bla.com

#!/bin/bash
source /somedir/hostfile.txt
echo $MACHINE_FQDN_VALUE

file_data '
  local file = "/somedir/hostfile.txt"
  local f = io.open(file, "r")
  local content = f:read("*all")
  f:close()
  ngx.print(content)
';