pulsar | libevent based multi-threaded web server | Websocket library

Topic says it all.

My guess is that the delivery guarantees of Pulsar make this question nonsensical but I would like to know for sure.

I've been considering some multiple consumer problem with my system and unfortunately I'm really stuck. I mean - I see some solutions, which are below, but they are propably not enought efficient. Let me introduce system:

User has their specific Id. User can be logged on diffrent devices - many mobiles, many browsers in this same time. When user is offline every message which user has got should be provide when user is online. When user is online, should be kept informed on a regular basis about messages. Every user, when is online is connected by WebSocket.

So I have been thinking about message brokers from this pool - rabbitmq, kafka, apache pulsar ( All system above will be in Java ). And this is my thoughs about this:

1. Rabbitmq - Every device gets their own queue associated with client Id. But here i see some troubles. For example - user gonna log in 4 browsers and each will get new queue ( of course I assume that some not used queue will be deleted after time but this solution can be overloaded if somebody just wanna do this ).

2. One queue with marker for every user which messages were consumed - I tried implement this with apache Pulsar but my every attempt was running out with created new consumer (not continue as the same consumer) - Maybe I can't use this API?

3. Apache kafka - groups and partitions? Its similiar to point 1.

I will be really gratefull for every single hint - If You see some better solutions with other technology just let me know - I will adjust to this.

( If it matters - Java and SpringBoot are core of this )

I have two modules like education and transport. I want to create modules and components for these. How to create a perfect folder structure for these. If anyone knows please help.

I followed the manual here: pulsar functions

I have this function declaration in Java:

I have been breaking my head with adding the below functionality in UI using HTML5 BOOTSTRAP-CSS-JS.

I am trying to create UI Dropdowns by consuming JSON input.

NOTE: The "JSON keys" are also to be consumed as dropdowns values rather than just the general "JSON values".. hence, i am unable to work out a logic for the same!

I have JSONs in the exact below format:

Clickhouse allows high performance writes but only if they are done in bulk and with intervals (recommended is at least 1 second interval between inserts). In the documentation to JDBC connector for Clickhouse batchSize option exists but there is nothing about intervals between inserts and I didn't manage to find insertion logic in the code (I am not a Java guy though).

Does it mean there are no intervals and Pulsar simply does inserts as frequently as it can?

Trying to configure a basic color detection in my ROS project, I got stuck in this: I have two python scripts where "programa.py" is my main robot program and the "camara.py" is my openCV color detection script.

Right now I can change the color detection publishing a string message when camara.py is running:

I'm trying to run a Pulsar DebeziumPostgresSource connector.

This is the command I'm running:

I'm working on a complex application that uses an Ignite version of log4j2. It works perfectly fine, but when I try to add a Pulsar appender it throws an error: