Reduce common boilerplate

[japgolly]

I'm always doing the same thing. Make this easier out-of-the-box:

  def sources: ConfigSources[IO] =
    // Highest pri
    ConfigSource.environment[IO].expandInlineProperties("APP_PROPS").mapKeyQueries(acceptExternalKeyFormat) >
      ConfigSource.propFileOnClasspath[IO]("app.properties", optional = true) >
      ConfigSource.system[IO]
  // Lowest pri

  private def acceptExternalKeyFormat(k: ConfigKey): List[ConfigKey] =
    k :: k.map(_.toUpperCase.replace('.', '_')) :: Nil

  def load: IO[Option[AppConfig]] =
    config
      .withReport
      .run(sources)
      .map { result =>
        result.toEither match {
          case Right((config, report)) =>
            if (config.showUnusedConfig)
              logger.info("Config report\n" + report.full)
            else
              logger.info("Config report\n" + report.sources + "\n\n" + report.used)
            Some(config)
          case Left(err) =>
            logger.error("Invalid config:\n" + err)
            None
        }
      }