Question

Is there a generic notion of asynchronous programming in python? Could I assign a callback to a function, execute it and return to the main program flow immediately, no matter how long the execution of that function would take?

Answer 1

Take a look here:

Asynchronous Programming in Python

An Introduction to Asynchronous Programming and Twisted

Worth checking out:

asyncio (previously Tulip) has been checked into the Python default branch

Edited on 14-Mar-2018

Today Python has asyncIO — Asynchronous I/O, event loop, coroutines and tasks built in.

Description taken from the link above:

The asyncIO module provides infrastructure for writing single-threaded
concurrent code using coroutines, multiplexing I/O access over sockets
and other resources, running network clients and servers, and other
related primitives. Here is a more detailed list of the package
contents:

1. a pluggable event loop with various system-specific implementations;
2. transport and protocol abstractions (similar to those in Twisted);
3. concrete support for TCP, UDP, SSL, subprocess pipes, delayed calls,
   and others (some may be system-dependent);
4. a Future class that mimics the one in the concurrent.futures module, but adapted for use with the event loop;
5. coroutines and tasks based on yield from (PEP 380), to
   help write concurrent code in a sequential fashion;
6. cancellation support for Futures and coroutines;
7. synchronization primitives for use
   between coroutines in a single thread, mimicking those in the
   threading module;
8. an interface for passing work off to a threadpool,
   for times when you absolutely, positively have to use a library that
   makes blocking I/O calls.

Asynchronous programming is more complex
than classical “sequential” programming: see the Develop with asyncio
page which lists common traps and explains how to avoid them. Enable
the debug mode during development to detect common issues.

Also worth checking out:

A guide to asynchronous programming in Python with asyncIO