Have a quick look at this previous conversation
https://groups.google.com/g/turn-server-project-rfc5766-turn-server/c/xSIV0i_IZZw/m/n0xB03sBDgAJ
The 3 choices for monitoring the allocations are:
1. Telnet session - This is easy enough if you are happy to write some code to issue telnet commands and do simple parsing of the results.
2. WebSession - I am not sure if there are any direct http requests that would get you the number of allocations.
3. Configure the turnserver process to use Redis for statistics and then query Redis to see the amount of activity.
Cheers,
Warren