python 绝版线程池

2.绝版线程池
设计思路：运用队列queue

a.队列里面放任务

b.线程一次次去取任务，线程一空闲就去取任务

import queue
import threading
import contextlib
import time

StopEvent = object()

class ThreadPool(object):

def __init__(self, max_num, max_task_num = None):
if max_task_num:
self.q = queue.Queue(max_task_num)
else:
self.q = queue.Queue()
self.max_num = max_num
self.cancel = False
self.terminal = False
self.generate_list = []
self.free_list = []

def run(self, func, args, callback=None):
"""
线程池执行一个任务
:param func: 任务函数
:param args: 任务函数所需参数
: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）
:return: 如果线程池已经终止，则返回True否则None
"""
if self.cancel:
return
if len(self.free_list) == 0 and len(self.generate_list) < self.max_num:
self.generate_thread()
w = (func, args, callback,)
self.q.put(w)

def generate_thread(self):
"""
创建一个线程
"""
t = threading.Thread(target=self.call)
t.start()

def call(self):
"""
循环去获取任务函数并执行任务函数
"""
current_thread = threading.currentThread()
self.generate_list.append(current_thread)

event = self.q.get()
while event != StopEvent:

func, args, callback = event
try:
result = func(*args)
success = True
except Exception as e:
success = False
result = None

if callback is not None:
try:
callback(success, result)
except Exception as e:
pass

with self.worker_state(self.free_list, current_thread):
if self.terminal:
event = StopEvent
else:
event = self.q.get()
else:

self.generate_list.remove(current_thread)

def close(self):
"""
执行完所有的任务后，所有线程停止
"""
self.cancel = True
count = len(self.generate_list)
while count:
self.q.put(StopEvent)
count -= 1

def terminate(self):
"""
无论是否还有任务，终止线程
"""
self.terminal = True

while self.generate_list:
self.q.put(StopEvent)

self.q.queue.clear()

@contextlib.contextmanager
def worker_state(self, state_list, worker_thread):
"""
用于记录线程中正在等待的线程数
"""
state_list.append(worker_thread)
try:
yield
finally:
state_list.remove(worker_thread)

# How to use

pool = ThreadPool(5)

def callback(status, result):
# status, execute action status
# result, execute action return value
pass

def action(i):
print(i)

for i in range(30):
ret = pool.run(action, (i,), callback)

time.sleep(3)
print(len(pool.generate_list), len(pool.free_list))
print(len(pool.generate_list), len(pool.free_list))
pool.close()
# pool.terminate()