Test.scala

import cats.effect.{ExitCode, IO, IOApp, Resource}
import cats.implicits._
import config.DataBaseConfig
import doobie.hikari.HikariTransactor
import doobie.implicits._
import doobie.util.ExecutionContexts

object Test extends IOApp {

  val dbConfig = DataBaseConfig()

  val transactor: Resource[IO, HikariTransactor[IO]] =
    for {
      ce <- ExecutionContexts.fixedThreadPool[IO](32) // our connect EC
      te <- ExecutionContexts.cachedThreadPool[IO] // our transaction EC
      xa <- HikariTransactor.newHikariTransactor[IO](
        "org.postgresql.Driver", // driver classname
        dbConfig.url, // connect URL =>  "jdbc:postgresql://localhost:5432/datalakes",
        dbConfig.userName, // username
        dbConfig.password, // password
        ce, // await connection here
        te // execute JDBC operations here
      )
    } yield xa

  def isDBHealthy =
    (xa: HikariTransactor[IO]) =>
      sql"select count(*) from DATA_TABLE"
        .query[Int]
        .option
        .transact(xa)
        .map(_ != None)

  override def run(args: List[String]): IO[ExitCode] =
    transactor
      .use { implicit xa: HikariTransactor[IO] =>
        val res = isDBHealthy(xa).unsafeRunSync()
        println(s"result within IOApp ===> $res")
        ExitCode.Success.pure[IO]
      }
}