如何使用Redis锁处理并发问题详解

import redis
r = redis.Redis(...)

last_heart = 0		# 记录上一次得到的锁心跳
free_lock_try = 6	# 锁无心跳的最大次数 

while not r.setnx('mylock', 1):
 now_heart = r.get('mylock')
 print(f"没获取到锁,now_heart={now_heart},last_heart={last_heart},free_lock_try={free_lock_try}")
 if now_heart == last_heart:
  free_lock_try = free_lock_try - 1
  if free_lock_try == 0:	# 锁已经1分钟没有心跳了
   old_heart = r.getset('mylock', 1)	# 将lock重置为1，并返回set之前的心跳值
   if old_heart < now_heart:
    time.sleep(10)
    continue
   else:
    break	# 成功获取到锁，退出循环
 else:
  free_lock_try = 6	# 锁有心跳，重置free_lock_try值
  last_heart = now_heart
 time.sleep(10)

def producer_exit():
 """程序正常退出时候自动清理锁"""
 r.delete('mylock')
import atexit
atexit.register(producer_exit)

# 业务代码
while True:
 r.incr('mylock')	# 让锁心跳加一
 ...