Proposal: Use Hocon format config

[rwadowski]

It appears that not all config values are not settable via environment variable. As for now kuiper utilizes config in the yaml format. Maybe it would be better to use Hocon format for configuration. It is similar syntax which allows to do something like this

kafka {
  servers="localhost:9092"
  servers=${?FC_BOOTSTRAP_SERVERS}
   ....

If there is FC_BOOTSTRAP_SERVERS in scope - its value will be read from the kafka.servers config, otherwise it will be localhost:9092.

It appears that there is conf library in go for this format -> here

[ngjaying]

@Rory-Z How do you think?

[Rory-Z]

@Rory-Z How do you think?

hocon is cool, but do we need to change the config file from yaml to hocon?