Python的异步编程[0] -> 协程[1] -> 使用协程建立自己的异步非阻塞模型

使用协程建立自己的异步非阻塞模型

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接下来例子中，将使用纯粹的Python编码搭建一个异步模型，相当于自己构建的一个asyncio模块，这也许能对asyncio模块底层实现的理解有更大的帮助。主要参考为文末的链接，以及自己的补充理解。

完整代码

  1 #!/usr/bin/python
  2 # =============================================================
  3 # File Name: async_base.py
  4 # Author: LI Ke
  5 # Created Time: 1/29/2018 09:18:50
  6 # =============================================================
  7 
  8 
  9 import types
 10 import time
 11 
 12 
 13 @types.coroutine
 14 def switch():
 15     print('Switch: Start')
 16     yield
 17     print('Switch: Done')
 18 
 19 async def coro_1():
 20     print('C1: Start')
 21     await switch()
 22     print('C1: Stop')
 23 
 24 
 25 async def coro_2():
 26     print('C2: Start')
 27     print('C2: 1')
 28     print('C2: 2')
 29     print('C2: 3')
 30     print('C2: Stop')
 31 
 32 c_1 = coro_1()
 33 c_2 = coro_2()
 34 
 35 try:
 36     c_1.send(None)
 37 except StopIteration:
 38     pass
 39 try:
 40     c_2.send(None)
 41 except StopIteration:
 42     pass
 43 try:
 44     c_1.send(None)
 45 except StopIteration:
 46     pass
 47 
 48 print('--------------------------------')
 49 
 50 def run(coros):
 51     coros = list(coros)
 52 
 53     while coros:
 54         # Duplicate list for iteration so we can remove from original list
 55         for coro in list(coros):
 56             try:
 57                 coro.send(None)
 58             except StopIteration:
 59                 coros.remove(coro)
 60 
 61 c_1 = coro_1()
 62 c_2 = coro_2()
 63 run([c_1, c_2])
 64 
 65 print('--------------------------------')
 66 
 67 @types.coroutine
 68 def action(t):
 69     trace=[]
 70     while True:
 71         trace.append(time.time())
 72         if trace[-1] - trace[0] > t:
 73             break # This break will end this function and raise a StopIteration
 74         yield
 75 
 76 async def coro_1():
 77     print('C1: Start')
 78     await action(2)
 79     print('C1: Stop')
 80 
 81 
 82 async def coro_2():
 83     print('C2: Start')
 84     await action(3)
 85     print('C2: Stop')
 86 
 87 def timeit(f):
 88     def _wrapper(*args, **kwargs):
 89         start = time.time()
 90         re = f(*args, **kwargs)
 91         end = time.time()
 92         print('Time cost:', f.__name__, end-start)
 93         return re
 94     return _wrapper
 95 
 96 c_1 = coro_1()
 97 c_2 = coro_2()
 98 timeit(run)([c_1])
 99 timeit(run)([c_2])
100 
101 print('--------------------------------')
102 
103 c_1 = coro_1()
104 c_2 = coro_2()
105 timeit(run)([c_1, c_2])

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