进程锁 购票问题

# Author：Winter Liu is coming!
import time
from multiprocessing import Process, Lock
import json


def search(i):
    with open("ticket_data", mode="r", encoding="utf-8") as f:
        ticket = json.load(f)
    print("{},票有{}张".format(i, ticket["count"]))


def buy_ticket(i, lock):
    # 锁定，中间部分代码唯一执行
    lock.acquire()

    with open("ticket_data", mode="r", encoding="utf-8") as f:
        ticket = json.load(f)
    if ticket["count"] > 0:
        ticket["count"] -= 1
        print("{}.购票成功！".format(i))
        time.sleep(0.2)
    with open("ticket_data", mode="w", encoding="utf-8") as f:
        json.dump(ticket, f)

    # 解锁
    lock.release()


if __name__ == "__main__":
    # 主进程创建 锁
    lock = Lock()
    for i in range(10):
        p = Process(target=buy_ticket, args=(i+1, lock))
        p.start()

修改后：

# Author：Winter Liu is coming!
import time
from multiprocessing import Process, Lock
import json


def ticket_search(i):
    with open("ticket_data", mode="r", encoding="utf-8") as f:
        ticket = json.load(f)
    print("{},票有{}张".format(i, ticket["count"]))


def buy_ticket(i):
    with open("ticket_data", mode="r", encoding="utf-8") as f:
        ticket = json.load(f)
    if ticket["count"] > 0:
        ticket["count"] -= 1
        print("{}.购票成功！".format(i))
        time.sleep(0.2)
    with open("ticket_data", mode="w", encoding="utf-8") as f:
        json.dump(ticket, f)


def get_tiket(i,lock):
    ticket_search(i)
    lock.acquire()
    buy_ticket(i)
    lock.release()

if __name__ == "__main__":
    # 主进程创建 锁
    lock = Lock()
    for i in range(10):
        p = Process(target=get_tiket, args=(i+1, lock))
        p.start()