I am new to python and trying to create a flask app that has a main thread of flask app and there are other threads being open for each task being run. Now I want to keep a track of each task and what data it is working on.So I thought to create something like:

There will be a listener like kafka does and my each task will be adding events like it has started or it has completed and according to that a function will run with the received/listened data.
Now the problem is it in not a big distributed system to use such complex and big thing like Kafka or rabbitMQ as it is a modular monolithic app.

So is there any python event listener or some thing that I can use for my flow.

I Don’t think making a function and calling a it instead of listner would help as it will wait for the function to return something.I want to make is loosely decoupled. Read about Can bus but can understand much.