Heartbeat lockdown

[rauhul]

The service should prevent any further requests to Merch if the pi does not response to a heartbeat sent out by this service. This will allow us to know as soon as the service goes down. This sort of heartbeat will be very useful for Concert and other future services and Merch provides a good platform to test it on.

[narendasan]

This would probably be better as a canopy feature if anything

[narendasan]

Also i think that ideally commands would not be synchronous, so state changes about the queue, or the inventory is not changed until a success confirmation from merch. so this could just be implemented as a timeout in the context of this service

[abrandemuehl]

Would it be possible to make something like a swagger API spec that I could generate the code from? That would make it much easier on my end, and we could reuse for other services.

I don't want to have to update it manually if the heartbeat API changes

[narendasan]

@abrandemuehl add it as an issue in https://github.com/acm-uiuc/canopy. I can develop a code stub that can be inserted for supported languages

[narendasan]

But I dont want to have groot trying to figure out uptime, it should work in a way where it assumes it works and handles failures. We are currently in the process of creating a service monitor for figuring out system status