ZIO learning - quick layer definition / published by https://github.com/dacr/code-examples-manager #0abcfad6-eb23-4b36-86c9-9d5efcbcd5e7/e3494686c613f075ee1c723be3103ada5fab4d33

zio-learning-31-layers-1.json

{"timestamp": "2022-03-04T11:25:50Z", "value": 41.0}
{"timestamp": "2022-03-04T11:26:17Z", "value": 42.0}
{"timestamp": "2022-03-04T11:26:42Z", "value": 42.0}

zio-learning-31-layers-1.sc

// summary : ZIO learning - quick layer definition
// keywords : scala, zio, layers, to-layer, nio, json, @testable
// publish : gist
// authors : David Crosson
// license : Apache License Version 2.0 (https://www.apache.org/licenses/LICENSE-2.0.txt)
// id : 0abcfad6-eb23-4b36-86c9-9d5efcbcd5e7
// attachments : zio-learning-31-layers-1.json
// created-on : 2022-03-04T11:20:53+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "dev.zio::zio:2.0.13"
//> using dep "dev.zio::zio-nio:2.0.1"
//> using dep "dev.zio::zio-json:0.5.0"
// ---------------------

/*
 Inspired from https://www.youtube.com/watch?v=PJTn33Qj1nc&ab_channel=Ziverge
 */

import zio.*
import zio.json.*
import zio.nio.file.*
import java.time.Instant

case class Sample(timestamp: Instant, value: Double)
object Sample:
  implicit val codec: JsonCodec[Sample] = DeriveJsonCodec.gen

case class Samples(temperatureSamples: Seq[Sample])

object Encapsulated extends ZIOAppDefault:

  val samples = ZLayer(
    for
      lines   <- Files.readAllLines(Path("zio-learning-31-layers-1.json"))
      samples <- ZIO.foreach(lines)(line => ZIO.fromEither(line.fromJson[Sample]))
    yield Samples(samples)
  )

  val logic =
    for
      samples <- ZIO.serviceWith[Samples](_.temperatureSamples)
      _       <- ZIO.foreach(samples)(t => Console.printLine(t.toJson))
    yield ()

  override def run = logic.provideSomeLayer(samples)

Encapsulated.main(args)