I am trying to add lock to timed key value store with python. Following is my code:

class TimedKVWithLock:
    def __init__(self):
        self.data = {}
        self._locks = defaultdict(threading.Lock)

    def put(self, key, value):
        with self._locks[key]:
            timestamp = int(time.time())
            if key not in self.data:
                self.data[key] = []
            self.data[key].append([timestamp, value])

    def get(self, key, timestamp):
        if key not in self.data:
            return ""
        with self._locks[key]:
            val_list = self.data[key]
            l = 0
            r = len(val_list) - 1
            result = ""
            while l <= r:
                m = (l + r) // 2
                if val_list[m][0] <= timestamp:
                    result = val_list[m][1]
                    l = m + 1
                else:
                    r = m - 1
            return result

Have some quick questions:

• Is following code going to work for multi threads case? Say I have N threads assessing the key values

• Do I need a global lock on self.data when I check if key exists in self.data?

thanks!