Redis key expire listener

README.md

Redis key expire listener

This code listens to redis key expire notifications

Installation

Set config in Redis config file as "notify-keyspace-events Ex"

pip3 install redis

You will find full details here

redis-key-expire-listener.py

import redis

# Whenever key expire notification comes this function get's executed
def event_handler(msg):
    print("Handler", msg)
    try:
        key = msg["data"].decode("utf-8")
        # If shadowKey is there then it means we need to proceed or else just ignore it
        if "shadowKey" in key:
            # To get original key we are removing the shadowKey prefix
            key = key.replace("shadowKey:", "")
            value = cache.get(key)
            # Once we got to know the value we remove it from Redis and do whatever required
            cache.delete(key)
            print("Got Value: ", value)
    except Exception as exp:
        pass

# Creating Redis and pubsub Connection
cache = redis.Redis()
pubsub = cache.pubsub()
# Set config in config file "notify-keyspace-events Ex"
# Subscribing to key expire events and whenver we get any notification sending it to event_handler function
pubsub.psubscribe(**{"__keyevent@0__:expired": event_handler})
pubsub.run_in_thread(sleep_time=0.01)