importasyncioasyncdefworker(semaphore,worker_id):asyncwithsemaphore:print(f"Worker {worker_id} is working")awaitasyncio.sleep(1)print(f"Worker {worker_id} has finished")asyncdefmain():semaphore=asyncio.Semaphore(3)# Limit concurrency to 3tasks=[worker(semaphore,i)foriinrange(10)]awaitasyncio.g...
通过使用 asyncio.Semaphore 和 “async with” 表达式，可以在协程中安全地获取和释放信号量，从而实现对...
File "<ipython-input-3-9b9bdb963407>", line 14 with (yield from sema): ^ SyntaxError: 'yield from' inside async function 我能想到的一些可能的解决方案…… 只需使用 @asyncio.coroutine 装饰器 使用threading.Semaphore?这似乎可能会导致其他问题 出于这个 原因,请在 Python 3.6 的测试版中尝试这个。
semaphore=asyncio.Semaphore(3)# 最多允许 3 个任务并行执行asyncdeffetch_url(session,url):asyncwithsemaphore:try:asyncwithsession.get(url)asresponse:data=awaitresponse.text()print(f"Fetched data from{url}:{len(data)}bytes")exceptExceptionase:print(f"Failed to fetch data from{url}:{e}")asyncd...
async with session.get(url) as response: response = await response.read() print(response) if __name__ == '__main__': loop = asyncio.get_event_loop() loop.run_until_complete(hello(url)) 首先async def 关键字定义了这是个异步函数,await 关键字加在需要等待的操作前面,response.read()等待...
sema = asyncio.Semaphore(3) asyncdeffetch_async(a): asyncwith aiohttp.request('GET', URL.format(a))as r: data =await r.json() return data['args']['a'] asyncdefprint_result(a): with (await sema): r =await fetch_async(a) ...
async def hello(url,semaphore): async with semaphore: async with aiohttp.ClientSession() as session: async with session.get(url) as response: return await response.read() async def run(): semaphore = asyncio.Semaphore(500) # 限制并发量为500 ...
Semaphore 表示同时允许多少个协程执行，Lock 表示只允许一个协程执行，例如：import asyncioasync defcoro(semaphore): async with semaphore:# do somethingasync defmain(): semaphore = asyncio.Semaphore(5) tasks = [asyncio.create_task(coro(semaphore)) for _ in range(10)] await asyncio...
使用semaphore = asyncio.Semaphore(500) 以及在协程中使用 async with semaphore: 操作 具体代码如下: import asyncio import aiohttp async def get_http(url): async with semaphore: async with aiohttp.ClientSession() as session: async with session.get(url) as res: ...
在上述代码中,我们首先创建了一个信号量对象semaphore,并将并发数量限制为2。然后,我们创建了5个worker协程任务,并将它们添加到任务列表中。在每个worker任务中,我们使用async with semaphore语句来获取信号量,表示当前任务需要占用一个信号量资源。在任务执行完毕后,会自动释放信号量资源。 通过这种方式,我们可以限制并发...