get notifications when kafka producer is online or offline

Question

I'm building a website using springboot as RestAPI and angular in frontend. Also, i will be getting data in my rest(consumer) from around 40-50 swing standalone apps(producers) through kafka. I need to implement online status for those swing apps. Basically, i need to know when and which one of swing apps went offline or back online. Is there a way to implement this? If this is impossible with kafka can you recommend something else for communication?

Clarification: By online status i mean whether device on which swing app is installed has internet connection or not. Swing app will be installed on around 40-50 devices on remote locations.

Answer 1

Eventually i got rid of kafka and used websockets. Using WebSocketHandler i had information when certain standalone app is connected or disconnected. When standalone app looses internet connection server is notified relatively quickly (within 60 seconds). Keep in mind that in my case standalone app will be sending data quite often. If this is not the case for you then i recommend looking for some other solutions and taking a look at @OneCriketeer comment regarding Nagios.