import asyncio

Brněnské Pyvi, 2014-01-30

Transcript

1. import asyncio Petr Viktorin encukou@gmail.com Pyvo, 2014-01-30
2. The problem Do something useful while waiting
3. The problem Do something useful while waiting (for IO)
4. The problems Do something useful while waiting (for IO) Do several things at the same time
5. Multiple processes import subprocess
6. Threads import threading
7. Greenlets Event loop Cooperative multitacking Monkeypatching pip install eventlet gevent
8. Callbacks Explicit cooperative multitasking pip install twisted
9. Help! Which do I use?
10. Compare: web frameworks
11. Compare: web frameworks Flask app
12. Compare: web frameworks Flask app Pyramid debug toolbar
13. Compare: web frameworks Flask app Pyramid debug toolbar Cherrypy logging
14. Compare: web frameworks Flask app Pyramid debug toolbar Cherrypy logging PEP 333 - Python Web Server Gateway Interface
15. Let's do the same for async!
16. Let's do the same for async! import asyncio
17. Let's do the same for async! import asyncio Python 3.4+
18. Let's do the same for async! import asyncio Python 3.4+ pip install tulip
19. Let's do the same for async! import asyncio Python 3.4+ pip install tulip Python 3.3+
20. asyncio Explicit cooperative multitasking
21. asyncio Explicit cooperative multitasking like Twisted
22. Global event loop
23. Global event loop Event loop policy
24. Callbacks
25. Callbacks call_soon(callback, args)
26. Callbacks call_soon(callback, args) call_later(delay, cb, *args)
27. Callbacks call_soon(callback, args) call_later(delay, cb, *args) What is time?
28. Callback style import asyncio def print_and_repeat(loop): print('Hello World') loop.call_later(2, print_and_repeat, loop) loop = asyncio.get_event_loop() loop.call_soon(print_and_repeat, loop) loop.run_forever()
29. Futures
30. Futures Placeholders for a result
31. Futures Placeholders for a result future.result()
32. Futures Placeholders for a result future.result() future.set_result()
33. Futures Placeholders for a result future.result() future.set_result() future.set_exception()
34. Futures Placeholders for a result future.result() future.set_result() future.set_exception() future.add_done_callback()
35. Futures Placeholders for a result future.result() future.set_result() future.set_exception() future.add_done_callback() concurrent.futures
36. Locks, Semaphores, Queues
37. Locks, Semaphores, Queues http://xkcd.com/927/
38. Couroutines & Tasks import asyncio @asyncio.coroutine def greet_every_two_seconds(): while True: print('Hello World') yield from asyncio.sleep(1) print('How are you?') yield from asyncio.sleep(1) loop = asyncio.get_event_loop() loop.run_until_complete(greet_every_two_seconds())
39. Transports & Protocols Transport: TCP, UDP, SSL Protocol: HTTP, FTP, IRC
40. Echo client import asyncio class EchoClient(asyncio.Protocol): message = 'This is the message. It will be echoed.' def connection_made(self, transport): transport.write(self.message.encode()) print('data sent: {}'.format(self.message)) def data_received(self, data): print('data received: {}'.format(data.decode())) def connection_lost(self, exc): print('server closed the connection') asyncio.get_event_loop().stop() loop = asyncio.get_event_loop() coro = loop.create_connection(EchoClient, '127.0.0.1', 8888) loop.run_until_complete(coro) loop.run_forever() loop.close()
41. Echo server import asyncio class EchoServer(asyncio.Protocol): def connection_made(self, transport): peername = transport.get_extra_info('peername') print('connection from {}'.format(peername)) self.transport = transport def data_received(self, data): print('data received: {}'.format(data.decode())) self.transport.write(data) # close the socket self.transport.close() loop = asyncio.get_event_loop() coro = loop.create_server(EchoServer, '127.0.0.1', 8888) server = loop.run_until_complete(coro) print('serving on {}'.format(server.sockets[0].getsockname())) try: loop.run_forever() except KeyboardInterrupt: print("exit") finally: server.close() loop.close()
42. ? Petr Viktorin @encukou.cz @encukou encukou@gmail.com github.com/encukou Slides available under the Creative Commons Attribution-ShareAlike 3.0 http://creativecommons.org/licenses/by-sa/3.0/
43. Sources & links PEP 3156 - Asynchronous IO Support Rebooted: the "asyncio" Module PEP 3148 - futures - execute computations asynchronously PEP 3153 (Superseded) - Asynchronous IO support http://docs.python.org/3.4/library/asyncio.html Youtube: Guido van Rossum - Tulip: Async I/O for Python 3