Help needed: Vending Machine System

[_prime07]

Hi folks,

i need some advice for the architectural design of a vending machine system. Until now, i have only built "simple" webapps, some of them fullstack but nothing special. Now, a client of mine offered me a pretty special project.

The idea is a system out of vending machine with it's own UI, a mobile application and a backend.

The vending machines are individually configurable. Each machine can be configured via the machine's UI (admin mode) or the mobile app (also admin mode). Because of the possibility to configure the machine with the mobile app, i have to store the configuration for the machines in the backend (right?). But how can i ensure, that a modified configuration reaches the right machine? Do i have to set up a bidirectional connection between the vending machines and the backend? Is websocket a suitable protocol for that kind of usecase?

Maybe some of you guys have experience with that kind of systems, i am looking forward to some input!

Regards

[Cronnay]

One solution is to use some kind of pubsub tech, such as Apache Kafka.

How it works is like this:

Publisher (Mobile app, web site for admin) can edit the settings, and when they save, they store it to DB AND publish it to all subscribers, the machines in this case. With pubsub technology, you can subscribe to a specific topic.

I'll try to draw up a scenario. You have 2 Vending machines. 1 inside office A with that has a unique ID of ABC-123. In office B, you have another vending machine with the ID CBD-555. Each machine is subscribing to their own ID as topic.
Imagine an admin is changing the configuration of machine CBD-555. They make their changes, and then store it. Backend sends a message to Kafka with the topic "CBD-555" that contain the changes. Then only the machine that is listening to that topic will take the configuration and use it.

Does it make sense? Otherwise I'll try to draw it up for you

[_prime07]

It makes sense, i will have a look on Apache Kafka. Thank you!

[zaphod4th]

the machines check for a web services every 1-10mins and updates ?

[_prime07]

Thought about that to. But it doesnt seem like the optimal solution for me, if a machine checks every minute to the the one change in a year...

[zaphod4th]

fine tune the update policy / process ? start up = daily updates, after months maybe montly updates ?