Trouble (rlm_python) with grpcio.

[s malinskiy]

Good day Team.

Several days ago I tried to use grpc for authentication in the python3
module, but
my request to the backend service failed.
That was pretty strange and I spent some time troubleshooting the problem.

First, all works well if I call script from *instantiate* section, but for
case if i try use call for example
in *authentication,* nothing happens (grpc constantly tries to reach
backend service) and radiusd stops proceeding new authentication requests.
I think there is some kind of threading issue of python.

Currently I don't have a solution to this issue but maybe you can help with
this.

ps. Centos8.x , freerad 3.20, python 3.6 and grpcio 1.37 if i dont mind.