Expiring messages in Redis

We are now onto the last requirement for our app, expiring messages. Since we are using Redis to store our messages, this becomes a trivial task.

Let's look back at our save_message method in our Redis dependency. Redis' SET has some optional parameters; the two we are most interested in here are ex and px. Both allow us to set the expiry of the data we are about to save, with one difference: ex is in seconds and px is in milliseconds:

def save_message(self, message): 
    message_id = uuid4().hex 
    self.redis.set(message_id, message, ex=10) 
 
    return message_id 

In the preceding code, you can see that the only amendment to the code I've made is to add ex=10 to the redis.set method; this will cause all of our messages to expire in 10 seconds. Restart your Nameko services now and try this out. When you send a new message, wait 10 seconds and refresh the page, and it should be gone.

Note

Please note that if there were any messages in Redis before you made this...