我正在努力将以前同步的网络服务器作为同步服务器。我的大部分功能都是同步的，我想简单地从现有代码中进行异步调用以避免异步蠕变。nest_asyncio 似乎通过使 run_until_complete 可重入来允许这样做。
但是，虽然这适用于 1 个可重入调用，但我遇到了两个死锁：
import asyncio
import functools
import time
from random import random
import nest_asyncio
nest_asyncio.apply()
def sync(corot, loop=None):
"""
Make a synchronous function from an asynchronous one.
:param corot:
:return:
"""
if loop is None:
loop = asyncio.get_event_loop()
result, = loop.run_until_complete(asyncio.gather(corot))
return result
async def sync_to_corountine(func, *args, **kw):
"""
Make a coroutine from a synchronous function.
"""
try:
return func(*args, *kw)
finally:
# every async needs an await.
await asyncio.sleep(0)
def main():
async def background(timeout):
await asyncio.sleep(timeout)
print(f"Background: {timeout}")
loop = asyncio.get_event_loop()
# Run some background work to check we are never blocked
bg_tasks = [
loop.create_task(background(i))
for i in range(10)
]
async def long_running_async_task(result):
# Simulate slow IO
print(f"...START long_running_async_task [{result}]")
await asyncio.sleep(1)
print(f"...END long_running_async_task [{result}]")
return result
def sync_function_with_async_dependency(result):
print(f"...START sync_function_with_async_dependency [{result}]")
result = sync(long_running_async_task(result), loop=loop)
print(f"...END sync_function_with_async_dependency [{result}]")
return result
# Call sync_function_with_async_dependency
# One reentrant task is OK
# Multiple reentrant tasks=>fails to exit
n = 2
for i in range(n):
bg_tasks.append(sync_to_corountine(sync_function_with_async_dependency, i))
# for i in range(n):
# bg_tasks.append(long_running_async_task(i))
# OK
# bg_tasks.append(long_running_async_task(123))
# bg_tasks.append(long_running_async_task(456))
task = asyncio.gather(*bg_tasks) # , loop=loop)
loop.run_until_complete(task)
if __name__ == '__main__':
main()
...START sync_function_with_async_dependency [0]
...START sync_function_with_async_dependency [1]
Background: 0
...START long_running_async_task [0]
...START long_running_async_task [1]
Background: 1
...END long_running_async_task [0]
...END long_running_async_task [1]
...END sync_function_with_async_dependency [1]
Background: 2
Background: 3
Background: 4
...我们失踪了
...END sync_function_with_async_dependency [0]
我是否正确使用了nest_asyncio？