尽管asyncio库是使用单线程来实现协程的，但是它还是并发的，乱序执行的。可以说是单线程的调度系统，并且由于执行时有延时或者I/O中断等因素，每个协程如果同步时，还是得使用一些同步对象来实现。
比如asyncio就定义了一个锁对象Lock，它一次只允许一个协程来访问共享的资源，如果多协程想访问就会阻塞起来，也就是说如果一个协程没有释放这个锁，别的协程是没有办法访问共享的资源。
例子：
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import asyncioimport functools def unlock(lock): print('callback releasing lock') lock.release() async def coro1(lock): print('coro1 waiting for the lock') with await lock: print('coro1 acquired lock') print('coro1 released lock') async def coro2(lock): print('coro2 waiting for the lock') await lock try: print('coro2 acquired lock') finally: print('coro2 released lock') lock.release() async def main(loop): # Create and acquire a shared lock. lock = asyncio.Lock() print('acquiring the lock before starting coroutines') await lock.acquire() print('lock acquired: {}'.format(lock.locked())) # Schedule a callback to unlock the lock. loop.call_later(0.1, functools.partial(unlock, lock)) # Run the coroutines that want to use the lock. print('waiting for coroutines') await asyncio.wait([coro1(lock), coro2(lock)]), event_loop = asyncio.get_event_loop()try: event_loop.run_until_complete(main(event_loop))finally: event_loop.close() |
输出结果如下：
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acquiring the lock before starting coroutineslock acquired: Truewaiting for coroutinescoro1 waiting for the lockcoro2 waiting for the lockcallback releasing lockcoro1 acquired lockcoro1 released lockcoro2 acquired lockcoro2 released lock |
以上这篇在python里协程使用同步锁Lock的实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/caimouse/article/details/77912534
