I have a piece of code, that checks if the redis db has data updates and loads them to the memory. I want only one corouitine to execute this load. class MyService: def __init__(self): self.lock = asyncio.Lock() self.latest_timestamp = None async def _check_latest_timestamp_from_db(self): # go to db async def ensure_update_loaded(): latest_timestamp_from_db = await self._check_latest_timestamp_from_db() if self.timestamp == latest_timestamp_from_db: return if self.lock.locked(): return # the load is in progress, we're okay to use the old data for now async with self.lock: # do the load self.timestamp = latest_timestamp_from_db From my understanding multiple coroutines can go simultaneously to this line: async with lock:, after all the checks are passed. Yes, they will execute consequently, but the load will happen more than once. I could double check within the lock: async with self.lock: if self.timestamp == latest_timestamp_from_db: return # do the load self.timestamp = latest_timestamp_from_db But I think there should be a clearer solution to my problem. Continue reading...
