setting up UDP connection between nodemcu and RPI

[Canedje]

I'm looking for some help.
I do have my home heating system controlled by two RPI's
One RPI is collecting temperature data. The other is controlling the heating by a Python programm and webserver as user interface.
This works fine.

Now I do like to replace one of the RPI's with a nodemcu Arduino ESP 8266. I want to connect a ds18b20 temperature sensor to the nodemcu collecting temperature data.
Communication must be happening by a UDP protocol by the network where the RPI is the server and the nodeMCU is a client
I'm looking some help by examples or tutorials to set up this UDP connection. I'm new to this stuff.
The code for the client (nodemcu) must be in C and on the RPI (server) in Python.
Can somebody give me some help around this stuff to start?