- 13.1 History service with streams: In our publish/subscribe example with Redis Stream, we didn't need a history service (as we did instead in the related AMQP example) because all the message history was saved in the stream anyway. Now, implement such a history service, storing all the incoming messages in a separate database and use this service to retrieve the chat history when a new client connects. Hint: the history service will need to remember the ID of the last message retrieved across restarts.
- 13.2 Multiroom chat: Update the chat application example we created in this chapter to be able to support multiple chat rooms. The application should also support displaying the message history when the client connects. You can choose the messaging system you prefer, and even mix different ones.
- 13.3 Tasks that stop: Update the hashsum cracker examples we implemented in this chapter and add the necessary logic to stop the computation on all nodes once...