Allow two-step parsing and decoding/binding

[rocketraman]

Modify ConfigLoader and ConfigParser so that the config is parsed only a single time. ConfigLoader.configBinder() can now be called to obtain the instance of a new class ConfigBinder, which can in turn be used to bind the already parsed config to multiple data classes, given a prefix.

This follows the general approach as suggested by @cloudshiftchris.

[sksamuel]

👍🏻

[osoykan]

I am using the library's snapshot version, this MR might have changed the behavior of the library. Nothing has changed on the app side of the code but, now I get an error on runtime while booting the app.

I am using with yaml, and the error source of the hoplite report is with command line args.

Example:

server:
  port: 8080
  host: localhost

app:
  kafka:
    bootstrap-servers: localhost:9092
    interceptorClasses: [ ]
    autoOffset: Earliest
    autoCreateTopics: true
    consume:
      group-id: app_name
      heartbeat-interval: 2s
      enabled: true
      consumers:
        AConsumer:
          group-id: 123
          topic: a-topic
          retry: a-topic-retry
          dead-letter: a-topic-error

CommandLineArgs also provide a new consumer configurations that are not in the application.yaml file (defined as resource to hoplite):

--app.kafka.consume.consumers.NewConsumer.topic=abc
--app.kafka.consume.consumers.NewConsumer.retry=abc2
// so on

Hoplite reports as "topic was absent", which is also the only property that does not have a default value on the data class.

So, I am not sure what is the problem, or how it appears but behavior was affected. I now changed the library to the stable 2.7.5 version and it works.

[rocketraman]

I am using the library's snapshot version, this MR might have changed the behavior of the library.

@osoykan Thank you for the report. Is it possible for you to create a small reproduction in a project or unit test?

[osoykan]

@rocketraman here you can find: https://github.com/osoykan/hoplite/commit/96378f0d6df1139ae4adcb4fd7caf0ecceb44d7f

[rocketraman]

@osoykan Thank you so much for raising this issue and creating a reproduction. I've found two related issues, and documented them here: https://github.com/sksamuel/hoplite/issues/443.

@sksamuel the fix for this regression is in PR https://github.com/sksamuel/hoplite/pull/444.

[osoykan]

Thanks a lot for solving it!