Python 线程 条件锁 生产者消费者模型

import threading
from threading import Thread
from threading import Condition
import time
import random
 
c = Condition()  # 条件锁
itemNum = 0
item = 0
 
def consumer():  # 消费者
    global item  # 商品编号
    global itemNum
    c.acquire()  # 锁住资源
    while 0 == itemNum:  # 如无产品则让线程等待
        print("consumer :挂起.", threading.current_thread().name, threading.current_thread())
        c.wait()
    itemNum -= 1
    print("consumer : 消费 %s." % item, itemNum, threading.current_thread().name, threading.current_thread())
    c.release()  # 解锁资源
 
def producer():  # 生产者
    global item  # 商品编号
    global itemNum
    time.sleep(3)
    c.acquire()  # 锁住资源
    item = random.randint(1, 1000)
    itemNum += 1
    print("producer : 生产 %s." % item, threading.current_thread().name, threading.current_thread())
    c.notifyAll()  # 唤醒所有等待的线程--》其实就是唤醒消费者进程
    c.release()  # 解锁资源
 
threads = []  # 线程收集列表
 
for i in range(0, 4):  # 使用循环完成生产者与消费者线程的建立
    t1 = Thread(target=producer, name=f‘pro_{i}‘)
    t2 = Thread(target=consumer, name=f"cos_{i}")
    t1.start()
    t2.start()
    threads.append(t1)
    threads.append(t2)
 
for t in threads:  # 等待所有线程完成
    t.join()