python中利用队列asyncio.Queue进行通讯详解_Python

python中利用队列asyncio.Queue进行通讯详解

2020-12-07 00:15caimouse Python

asyncio是Python 3.4版本引入的标准库,直接内置了对异步IO的支持。下面这篇文章主要给大家介绍了关于python中利用队列asyncio.Queue进行通讯的相关资料，文中通过示例代码介绍的非常详细，需要的朋友可以参考下。

前言

本文主要给大家介绍了关于python用队列asyncio.Queue通讯的相关内容，分享出来供大家参考学习，下面话不多说了，来一起看看详细的介绍吧。

asyncio.Queue与其它队列是一样的，都是先进先出，它是为协程定义的

例子如下：

									import asyncio 

									async def consumer(n, q): 

									 print('consumer {}: starting'.format(n)) 

									 while True: 

									  print('consumer {}: waiting for item'.format(n)) 

									  item = await q.get() 

									  print('consumer {}: has item {}'.format(n, item)) 

									  if item is None: 

									   # None is the signal to stop. 

									   q.task_done() 

									   break

									  else: 

									   await asyncio.sleep(0.01 * item) 

									   q.task_done() 

									 print('consumer {}: ending'.format(n)) 

									async def producer(q, num_workers): 

									 print('producer: starting') 

									 # Add some numbers to the queue to simulate jobs 

									 for i in range(num_workers * 3): 

									  await q.put(i) 

									  print('producer: added task {} to the queue'.format(i)) 

									 # Add None entries in the queue 

									 # to signal the consumers to exit 

									 print('producer: adding stop signals to the queue') 

									 for i in range(num_workers): 

									  await q.put(None) 

									 print('producer: waiting for queue to empty') 

									 await q.join() 

									 print('producer: ending') 

									async def main(loop, num_consumers): 

									 # Create the queue with a fixed size so the producer 

									 # will block until the consumers pull some items out. 

									 q = asyncio.Queue(maxsize=num_consumers) 

									 # Scheduled the consumer tasks. 

									 consumers = [ 

									  loop.create_task(consumer(i, q)) 

									  for i in range(num_consumers) 

									 ] 

									 # Schedule the producer task. 

									 prod = loop.create_task(producer(q, num_consumers)) 

									 # Wait for all of the coroutines to finish. 

									 await asyncio.wait(consumers + [prod]) 

									event_loop = asyncio.get_event_loop() 

									try: 

									 event_loop.run_until_complete(main(event_loop, 2)) 

									finally: 

									 event_loop.close()

输出如下：

									consumer 0: starting

									consumer 0: waiting for item

									consumer 1: starting

									consumer 1: waiting for item

									producer: starting

									producer: added task 0 to the queue

									producer: added task 1 to the queue

									consumer 0: has item 0

									consumer 1: has item 1

									producer: added task 2 to the queue

									producer: added task 3 to the queue

									consumer 0: waiting for item

									consumer 0: has item 2

									producer: added task 4 to the queue

									consumer 1: waiting for item

									consumer 1: has item 3

									producer: added task 5 to the queue

									producer: adding stop signals to the queue

									consumer 0: waiting for item

									consumer 0: has item 4

									consumer 1: waiting for item

									consumer 1: has item 5

									producer: waiting for queue to empty

									consumer 0: waiting for item

									consumer 0: has item None

									consumer 0: ending

									consumer 1: waiting for item

									consumer 1: has item None

									consumer 1: ending

									producer: ending