awake-every-cats-effect.scala

 import cats.effect.{ExitCode, IO, IOApp, Timer}
import cats.syntax.apply._
import cats.syntax.functor._

import scala.concurrent.duration._

object scheduler extends IOApp {

  def repeatAtFixedRate(period: FiniteDuration, task: IO[Unit])
                       (implicit timer: Timer[IO]): IO[Unit] =
    timer.clock.realTime(MILLISECONDS).flatMap { start =>
      task *> timer.clock.realTime(MILLISECONDS).flatMap { finish =>
        val nextDelay = period.toMillis - (finish - start)
        timer.sleep(nextDelay.millis) *> repeatAtFixedRate(period, task)
      }
    }

  val ioa = IO(println("Hello World!"))

  override def run(args: List[String]): IO[ExitCode] =
    repeatAtFixedRate(1.second, ioa).as(ExitCode.Success)

}