如何使用python asyncio编码consumer.producer? [英] How to code consumer.producer with python asyncio?

问题描述

我的Python版本是3.6.1

My Python version is 3.6.1.

我写了一些东西来用Python asyncio实现消费者生产者模型. 但这并没有按预期工作.

I wrote something to implement a model of consumer-producer with Python asyncio. But it doesn't work as expected.

全部创建了四个事件，但没有任何打印输出.

Four events all created but none of any print export.

async def consumer(queue, id):
    while True:
        val = await queue.get()
        print('{} get a val: {}'.format(id, val))
        await asyncio.sleep(1)

async def producer(queue, id):
    for i in range(5):
        val = random.randint(1, 10)
        await queue.put(val)
        print('{} put a val: {}'.format(id, val))
        await asyncio.sleep(1)

async def main():
    queue = asyncio.Queue()

    consumer_1 = asyncio.ensure_future(consumer(queue, 'consumer_1'))
    consumer_2 = asyncio.ensure_future(consumer(queue, 'consumer_2'))

    producer_1 = asyncio.ensure_future(producer(queue, 'producer_1'))
    producer_2 = asyncio.ensure_future(producer(queue, 'producer_2'))

    await asyncio.sleep(10)
    consumer_1.cancel()
    consumer_2.cancel()

    await asyncio.gather(consumer_1, consumer_2, producer_1, producer_2, return_exceptions=True)

loop = asyncio.get_event_loop()
tasks = [asyncio.ensure_future(main())]
loop.run_until_complete(asyncio.wait(tasks))
loop.close()

你能帮我改正吗?

推荐答案

您的方法中有很多错误，其中一些是:

A lot of wrong things in your approach, some of those are:

• 生产者
的
• 不必要的asyncio.ensure_future
• asyncio.gather以可疑物品的任意顺序
• 不必要的tasks = [asyncio.ensure_future(main())]和asyncio.wait(tasks)操作
• 不受控制的queue

• unnecessary asyncio.ensure_future for producers
• asyncio.gathering in arbitrary order with doubtful items
• unnecessary tasks = [asyncio.ensure_future(main())] and asyncio.wait(tasks) actions
• uncontrolled queue

asyncio生产者/消费者方案的示例: https://asyncio.readthedocs.io/en/latest/producer_consumer.html

Example of asyncio Producer/consumer scheme: https://asyncio.readthedocs.io/en/latest/producer_consumer.html

正确的生产者/消费者方案如下所示(针对您的情况):

The correct producer/consumer scheme would look as below (for your case):

import asyncio
import random

async def consumer(queue, id):
    while True:
        val = await queue.get()
        print('{} get a val: {}'.format(id, val))
        await asyncio.sleep(1)
        queue.task_done()   # indicate complete task

async def producer(queue, id):
    for i in range(5):
        val = random.randint(1, 10)
        await asyncio.sleep(1)
        await queue.put(val)
        print('{} put a val: {}'.format(id, val))


async def main():
    queue = asyncio.Queue()

    producer_1 = producer(queue, 'producer_1')
    producer_2 = producer(queue, 'producer_2')

    consumer_1 = asyncio.ensure_future(consumer(queue, 'consumer_1'))
    consumer_2 = asyncio.ensure_future(consumer(queue, 'consumer_2'))

    await asyncio.gather(*[producer_1, producer_2], return_exceptions=True)
    await queue.join()  # wait until the consumer has processed all items
    consumer_1.cancel()
    consumer_2.cancel()

loop = asyncio.get_event_loop()
loop.run_until_complete(main())
loop.close() 

输出:

producer_1 put a val: 7
producer_2 put a val: 2
consumer_1 get a val: 7
consumer_2 get a val: 2
producer_1 put a val: 9
producer_2 put a val: 2
consumer_1 get a val: 9
consumer_2 get a val: 2
producer_1 put a val: 9
producer_2 put a val: 3
consumer_1 get a val: 9
consumer_2 get a val: 3
producer_1 put a val: 1
producer_2 put a val: 6
consumer_1 get a val: 1
consumer_2 get a val: 6
producer_1 put a val: 2
producer_2 put a val: 2
consumer_1 get a val: 2
consumer_2 get a val: 2

这篇关于如何使用python asyncio编码consumer.producer?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！