redis 鎖的案例

1: redis 鎖 做爲一種術裝飾器使用redis

  基本邏輯:spa

    1:聲明一個redislock類  定義生成鎖和釋放鎖兩個方法code

    2:生成鎖使用了一個默認值 setnx ; 若是當前時間大於 第一次鎖的生成時間就從新生成(循環一次鎖的時間更新一次)對象

    3:釋放鎖:在設置的時間範圍timeout 內 , 就釋放鎖blog

    3:定義一個裝飾器方法 參數是redis鎖對象(寫法值得借鑑)get

  

import time
import redis


class RedisLock(object):
    def __init__(self, key):
        self.rdcon = redis.Redis(host='localhost', port=6379,  db=1)
        self._lock = 0
        self.lock_key = "%s_dynamic_test" % key

    @staticmethod
    def get_lock(cls, timeout=10):
        while cls._lock != 1:
            timestamp = time.time() + timeout + 1
            cls._lock = cls.rdcon.setnx(cls.lock_key, timestamp)

            if cls._lock == 1 or (
                    time.time() > float(cls.rdcon.get(cls.lock_key)) and time.time() > float(cls.rdcon.getset(cls.lock_key,
                                                                                                 timestamp))):
                print("get lock")
                break
            else:
                time.sleep(0.3)

    @staticmethod
    def release(cls):
        print('*'*10)
        print(time.time())
        print(cls.rdcon.get(cls.lock_key))
        if time.time() < float(cls.rdcon.get(cls.lock_key)):
            print("release lock")

            cls.rdcon.delete(cls.lock_key)


def deco(cls):
    def _deco(func):
        def __deco(*args, **kwargs):
            print("before %s called [%s]." % (func.__name__, cls))
            cls.get_lock(cls)
            try:
                return func(*args, **kwargs)
            finally:
                cls.release(cls)

        return __deco

    return _deco


@deco(RedisLock("112233"))
def myfunc():
    print("myfunc() called.")
    time.sleep(5)
    print('end..')


if __name__ == "__main__":
    myfunc()
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