simple elastic4s sample using Cats Effect and Circe

ArtistIndex.scala

package trial1

import cats.effect._
import cats.instances.list._
import cats.syntax.flatMap._
import cats.syntax.functor._
import cats.syntax.traverse._
import com.sksamuel.elastic4s.circe._
import com.sksamuel.elastic4s.http.search.SearchResponse
import com.sksamuel.elastic4s.http._
import com.sksamuel.elastic4s.indexes.{CreateIndexRequest, IndexRequest}
import com.sksamuel.elastic4s.searches.SearchRequest
import io.circe.generic.auto._

case class ModernArtist(name2: String)

trait Program[F[_]] {
  import com.sksamuel.elastic4s.http.ElasticDsl._
  implicit val F: Sync[F]

  private def puts(s: Any): F[Unit] = F.delay { println(s) }

  val createArtists: CreateIndexRequest = createIndex("artists") mappings {
    mapping("modern") fields textField("name")
  }
  val indexModern: IndexRequest =
    indexInto("artists" / "modern") source ModernArtist("L.S. Lowry") refreshImmediately

  val searchModern: SearchRequest = search("artists") query "lowry"

  def client: Resource[F, ElasticClient] = Resource.make {
    F.delay { ElasticClient(ElasticProperties("http://127.0.0.1:9200")) }
  } (c => F.delay { c.close() })

  def report(res: Response[SearchResponse]): F[Unit] = res match {
    case RequestFailure(_, _, _, e) => puts(s"We failed: $e")
    case RequestSuccess(_, _, _, r) => for {
      _ <- r.to[ModernArtist].toList.map(puts(_)).sequence
      _ <- puts(s"There were ${r.totalHits} total hits")
    } yield ()
  }

  def program(implicit U: Functor[F], E: Executor[F]): F[Unit] = client use { c =>
    for {
      _ <- c.execute(createArtists)
      _ <- c.execute(indexModern)
      _ <- c.execute(searchModern) >>= report
    } yield ()
  }
}
object ArtistIndex extends IOApp with Program[IO] {
  import com.sksamuel.elastic4s.cats.effect.instances._
  val F: Sync[IO] = Sync[IO]

  def run(args: List[String]): IO[ExitCode] = program as ExitCode.Success
}