绝版线程池

  1 import queue
  2 import threading
  3 import contextlib
  4 import time
  5 
  6 StopEvent = object()
  7 
  8 
  9 class ThreadPool(object):
 10 
 11     def __init__(self, max_num):
 12 
 13         self.q = queue.Queue()
 14         #最多创建线程数
 15         self.max_num = max_num
 16         self.cancel = False
 17         self.terminal = False
 18         #真实创建的线程列表
 19         self.generate_list = []
 20         #空闲的线程列表
 21         self.free_list = []
 22 
 23     def run(self, func, args, callback=None):
 24         """
 25         线程池执行一个任务
 26         :param func: 任务函数
 27         :param args: 任务函数所需参数
 28         :param callback: 任务执行失败或成功后执行的回调函数，回调函数有两个参数1、任务函数执行状态；2、任务函数返回值（默认为None，即：不执行回调函数）
 29         :return: 如果线程池已经终止，则返回True否则None
 30         """
 31         if self.cancel:
 32             return
 33         if len(self.free_list) == 0 and len(self.generate_list) < self.max_num:
 34             self.generate_thread()
 35         w = (func, args, callback,)
 36         self.q.put(w)
 37 
 38     def generate_thread(self):
 39         """
 40         创建一个线程
 41         """
 42         t = threading.Thread(target=self.call)
 43         t.start()
 44 
 45     def call(self):
 46         """
 47         循环去获取任务函数并执行任务函数
 48         """
 49         current_thread = threading.currentThread()
 50         self.generate_list.append(current_thread)
 51 
 52         event = self.q.get()
 53         while event != StopEvent:
 54 
 55             func, arguments, callback = event
 56             try:
 57                 result = func(*arguments)
 58                 success = True
 59             except Exception as e:
 60                 success = False
 61                 result = None
 62 
 63             if callback is not None:
 64                 try:
 65                     callback(success, result)
 66                 except Exception as e:
 67                     pass
 68 
 69             with self.worker_state(self.free_list, current_thread):
 70                 if self.terminal:
 71                     event = StopEvent
 72                 else:
 73                     event = self.q.get()
 74         else:
 75 
 76             self.generate_list.remove(current_thread)
 77 
 78     def close(self):
 79         """
 80         执行完所有的任务后，所有线程停止
 81         """
 82         self.cancel = True
 83         full_size = len(self.generate_list)
 84         while full_size:
 85             self.q.put(StopEvent)
 86             full_size -= 1
 87 
 88     def terminate(self):
 89         """
 90         无论是否还有任务，终止线程
 91         """
 92         self.terminal = True
 93 
 94         while self.generate_list:
 95             self.q.put(StopEvent)
 96 
 97         self.q.queue.clear()
 98 
 99     @contextlib.contextmanager
100     def worker_state(self, state_list, worker_thread):
101         """
102         用于记录线程中正在等待的线程数
103         """
104         state_list.append(worker_thread)
105         try:
106             yield
107         finally:
108             state_list.remove(worker_thread)
109 
110 
111 
112 pool = ThreadPool(5)
113 
114 def callback(status, result):
115     # status, execute action status
116     # result, execute action return value
117     pass
118 
119 
120 def action(i):
121     print(i)
122 
123 for i in range(30):
124     ret = pool.run(action, (i,), callback)
125 
126 time.sleep(5)
127 
128 print(len(pool.generate_list), len(pool.free_list))
129 print(len(pool.generate_list), len(pool.free_list))
130 # pool.close()
131 pool.terminate()

 

转载于:https://www.cnblogs.com/shiluoliming/p/6442715.html