Setting env values to Hocon props

[arlengur]

Hocon doc says:
By setting the JVM property -Dconfig.override_with_env_vars=true it is possible to override any configuration value using environment variables even if an explicit substitution is not specified.

The environment variable value will override any pre-existing value and also any value provided as Java property.

With this option enabled only environment variables starting with CONFIG_FORCE_ are considered, and the name is mangled as follows:

• the prefix CONFIG_FORCE_ is stripped
• single underscore(_) is converted into a dot(.)

Set array values outside configuration files
Setting the value of array items from java properties or environment variables require specifying the index in the array for the value. So, while in HOCON you can set multiple values into an array or append to an array.
Using environment variables you specify the exact position.

My config application.conf:

HttpServerConfig {
  # The port to listen on.
  port = 8080
  port = ${?PORT}

  # The hostname to listen on.
  host = "localhost"
  host = ${?HOST}

  source = ["LEGACY_HISTORICAL", "./src/test/resources/marmot_day_test1.tsv"]
  path = []
}

Here is main class:

import zio._
import zio.config.magnolia._
import zio.config.typesafe.TypesafeConfigProvider

case class HttpServerConfig(
  host: String,
  port: Int,
  sourceFilePath: List[String],
  path: List[String],
)

object HttpServerConfig {
  implicit val config: Config[HttpServerConfig] =
    deriveConfig[HttpServerConfig].nested("HttpServerConfig")
}

object MainA extends ZIOAppDefault {
  override val bootstrap = Runtime.setConfigProvider(TypesafeConfigProvider.fromResourcePath())

  val workflow = ZIO
    .config[HttpServerConfig](HttpServerConfig.config)
    .flatMap { config =>
      Console.printLine(
        "Application started with following configuration:\n" +
          s"\thost: ${config.host}\n" +
          s"\tport: ${config.port}\n" +
          s"\tsource: ${config.source}\n" +
          s"\tpath: ${config.path}"
      )
    }

  def run = workflow
}

And the same code works for TypesafeConfig.
Here is my example https://github.com/arlengur/zio-conf

Just run:
CONFIG_FORCE_HttpServerConfig_path_0=z CONFIG_FORCE_HttpServerConfig_path_1=q sbt run -Dconfig.override_with_env_vars=true
And you will get output from TypesafeConfig and error from ZIO

What's wrong here?!