# -*- coding: utf-8 -*-

"""

多进程 锁使用

逻辑:

    10个进程各种睡眠2秒，然后打印。

    不加锁同时打印出来，总共2秒，加锁一个接一个打印，总共20秒

总结：

    1、Lock 只要1把锁，RLock 有多把锁，但是不清楚什么场景只适合用RLock

使用:

    1. 创建所   lock = Lock() or lock = RLock()

    2. 把锁当做参数传入给子进程

    3. 在子进程执行代码中对代码块，加锁 lock.acquire(); 其他代码 lock.release()

"""

from multiprocessing import Process, Lock, RLock

import    time

# 不加锁

def f(l, i):

    time.sleep(2)

    print(time.strftime('%M:%S', time.localtime(time.time())),'hello world', i)

# 加Lock

def f2(l, i):

    l.acquire()  # 竞争锁

    time.sleep(2)

    print(time.strftime('%M:%S', time.localtime(time.time())),'hello world', i)

    l.release()  # 释放锁

# 加Rlock

def f3(l, i):

    l.acquire() # 竞争锁

    l.acquire() #  抢到锁后，再加一把锁

    time.sleep(2)

    print(time.strftime('%M:%S', time.localtime(time.time())),'hello world', i)

    l.release() # 释放锁

    l.release() # 前面几个acquire，这里就有几个 release 如果注释掉，其他进程阻塞

if __name__ == '__main__':

    lock = Lock()

    rlock = RLock()

    import ptools;ptools.checkname(rlock);exit(0)

    # base

    # for num in range(10):

    #     Process(target=f, args=(None, num)).start()

    # case1

    for num in range(10):

        Process(target=f2, args=(lock, num)).start()

    #

    # # case2

    # for num in range(10):

    #     Process(target=f3, args=(rlock, num)).start()

"""

Out:

不加锁

('49:31', 'hello world', 3)

('49:31', 'hello world', 2)

('49:31', 'hello world', 1)

('49:31', 'hello world', 7)

('49:31', 'hello world', 8)

('49:31', 'hello world', 5)

('49:31', 'hello world', 6)

('49:31', 'hello world', 4)

('49:31', 'hello world', 9)

('49:31', 'hello world', 0)

case1 加锁,case2差不多

'49:52', 'hello world', 0)

('49:54', 'hello world', 7)

('49:56', 'hello world', 2)

('49:58', 'hello world', 5)

('50:00', 'hello world', 4)

('50:02', 'hello world', 3)

('50:04', 'hello world', 8)

('50:06', 'hello world', 1)

('50:08', 'hello world', 6)

('50:10', 'hello world', 9)

"""