Going asynchronous with Python

Slides from my joint workshop at PyCon Finland 2011

Transcript

1. Jyrki Pulliainen / 18.10.2011 / Going concurrent asynchronous with Python Wednesday, October 19, 2011
2. Going asynchronous with Python / Motivation • Not threaded • Good for I/O bound software • Buzzword-compatible! Wednesday, October 19, 2011
3. Going asynchronous with Python / Two ways to achieve • Coroutines • Event loop Wednesday, October 19, 2011
4. Going asynchronous with Python / Coroutines • Components, that are suspendable / resumable • One scheduler to rule them all Wednesday, October 19, 2011
5. Going asynchronous with Python / Coroutines in Python • Python 2.5 added support for coroutines >>>def coroutine(): >>> input = yield i >>> print i + 1 >>> a = coroutine() >>> a.next() >>> a.send(1) 2 Wednesday, October 19, 2011
6. Going asynchronous with Python / Running multiple coroutines def main_loop(self): while self.tasks_left(): task = self.get_next_task() try: task.send(None) except StopIteration: # Do not schedule if the task is done self.remove_task(task) Wednesday, October 19, 2011
7. Going asynchronous with Python / Event loop • Good for I/O • Main idea: Wait for something to happen, then pass to a handler Wednesday, October 19, 2011
8. Going asynchronous with Python / Idea in a nutshell class EventLoop(object): # ... def main_loop(): while True: event = self.wait_for_event() handler = self.get_handler_for_event(handler) handler() Wednesday, October 19, 2011
9. Going asynchronous with Python / Finding events • Usually you want to poll I/O • Tools for that: select, kselect, epoll... Wednesday, October 19, 2011
10. Jyrki Pulliainen / 18.10.2011 / CODE TIEM!!11 (actually, just looking at it) Wednesday, October 19, 2011