Yes, it also using python-sdbus.
I wondering what really happens with simultaneous calls, do we need to see these the same like having separate async task running at the same time on the servers side? Asking this because then I would need to use asyncio.Locks for critical section...?

The way asyncio works is that it only switches between concurrent tasks when await is invoked. If your call handler only uses blocking calls it will never switch to another call mid execution.

It makes sense to use asyncio.Lock when you have some shared resource that does not support concurrency.

However, because task switching is predictable and only happens on await some read-modify-write loops won't need locking if they are completely blocking.

i = 0

async def test():
    global i
    i = i + 1

This function will be concurrency safe in asyncio because it does not use await between where it reads the value and modifies it.

@igo95862 Thank you for the clarifications