用管理學的 PDCA 循環理解 Python 3.7 的非同步處理

async_pdca.py

import random
import asyncio

class PDCACycle:

    def __init__(self):
        self.bad_mood = 0
        self.interval = 1

    async def plan(self, name):
        await asyncio.sleep(random.random() * 1.2)
        return 'Plan {}'.format(name)

    async def do(self):
        (done, pending) = await asyncio.wait([
            self.plan('A'),
            self.plan('B'),
            self.plan('C')
        ], timeout=1.0)
        plans = []
        for task in done:
            plans.append(task.result())
        print('({}) -> '.format(', '.join(plans)), end='', flush=True)

        await asyncio.sleep(self.interval)
        delayed = len(done) < 3
        if delayed:
            print('Delay -> ', end='', flush=True)
        else:
            print('Do -> ', end='', flush=True)

        await asyncio.sleep(self.interval)
        return delayed

    async def check(self):
        delayed = await self.do()
        if delayed:
            print('Cancel -> ', end='', flush=True)
        else:
            print('Check -> ', end='', flush=True)

        await asyncio.sleep(self.interval)
        return delayed

    async def act(self):
        canceled = await self.check()
        if canceled:
            print('Apologize', end='', flush=True)
            self.bad_mood += 1
        else:
            print('Act', end='', flush=True)

        return

    def run(self, threshold):
        print('Join the team.')
        while self.bad_mood < threshold:
            asyncio.run(self.act())
            print(' (Bad mood: {})'.format(self.bad_mood))
        print('Leave the team.')

def main():
    cycle = PDCACycle()
    cycle.run(5)

if __name__ == '__main__':
    main()

Output

Join the team.
(Plan B) -> Delay -> Cancel -> Apologize (Bad mood: 1)
(Plan B, Plan C, Plan A) -> Do -> Check -> Act (Bad mood: 1)
(Plan B, Plan C) -> Delay -> Cancel -> Apologize (Bad mood: 2)
(Plan B, Plan C) -> Delay -> Cancel -> Apologize (Bad mood: 3)
(Plan A, Plan B, Plan C) -> Do -> Check -> Act (Bad mood: 3)
(Plan A, Plan C) -> Delay -> Cancel -> Apologize (Bad mood: 4)
(Plan C, Plan B) -> Delay -> Cancel -> Apologize (Bad mood: 5)
Leave the team.