Exit application if environment verification failed

[welandaz]

Description of the Change

This change performs exit from Java process if AbstractService.verifyEnvironment() throws an exception during application start up.

Benefits

Currently, if method throws an exception, process stays alive, even though application won't function properly. This change makes sure, that if application's environment isn't valid (or something went wrong while trying to verify it), the program will terminate with the proper error logged. (Before, even though the message was logged, application continued to work in a broken state and could potentially confuse monitoring systems)

Possible Drawbacks

None, unless the semantic of AbstractService.verifyEnvironment() isn't supposed to be treated like that and it's ok to fail and not terminate the application (or if someone has been using it like that already, in which case after this fix application won't start unless no exception is thrown)

[bkrahmer]

I see the point of what you are suggesting. However, the design is as it is intentionally. In a k8s environment, if you start-up, realize your environment isn't complete and exit the process, it will just result in a non-stop series of service restarts. I'm not sure that is any better than a stalled container (with a critical health status).

[codec]

👍 having this control in the service sounds good to me

[welandaz]

@bkrahmer @codec Ok, I see the problem here, however there is already a process termination in case no OrangeMicroservice annotation was found (or service was ran with 'help' argument).

Doesn't that break the intent too? (k8s will try to start the app again)

[bkrahmer]

Those are two cases not relevant to the real-world use cases. The first would be found by testing the service before deploying, and the second is just a mis-use.