《流畅的python》线程、协程的对比示例

spinner_thread.py

import threading
import itertools
import time
import sys

class Signal:
    go = True

def spin(msg, signal):
    write, flush = sys.stdout.write, sys.stdout.flush
    for char in itertools.cycle('|/-\\'):
        status = char + ' ' + msg
        write(status)
        flush()
        write('\x08'*len(status))
        time.sleep(0.1)
        if not signal.go:
            break
    write(' ' * len(status) + '\x08'*len(status))

def slow_function():
    time.sleep(3)
    return 42

def supervisor():
    signal = Signal()
    spinner = threading.Thread(target=spin, args=('thinking!', signal))
    print ('spinner object:', spinner)
    spinner.start()
    result = slow_function()
    signal.go = False
    spinner.join()
    return result

def main():
    result = supervisor()
    print ('Answer:', result)

if __name__ == '__main__':
    main()

spinner_asyncio.py

import asyncio
import itertools
import sys

@asyncio.coroutine
def spin(msg):
    write, flush = sys.stdout.write, sys.stdout.flush
    for char in itertools.cycle('|/-\\'):
        status = char + ' ' + msg
        write(status)
        flush()
        write('\x08' * len(status))
        try:
            yield from asyncio.sleep(.1)
        except asyncio.CancelledError:
            break
    write(' ' * len(status) + '\x08' * len(status))

@asyncio.coroutine
def slow_function():
    # 假装等待I/O一段时间
    yield from asyncio.sleep(3)
    return 42

@asyncio.coroutine
def supervisor():
    spinner = asyncio.async(spin('thinking!'))
    print ('spinner object:', spinner)
    result = yield from slow_function()
    spinner.cancel()
    return result

def main():
    loop = asyncio.get_event_loop()
    result = loop.run_until_complete(supervisor())
    loop.close()
    print ('Answer:', result)

if __name__ == '__main__':
    main()