gistfile1.scala

  def apply[A](attempt: Int)(f: Conn => A): A = {
    val node       = nextLiveNode()
    val pool       = node.pool
    val connection = pool.borrow()
    
    try {
      val value = f(connection)
      pool.giveBack(connection)
      value
    } catch {
      case e: Throwable if attempt == maxRetries => pool.invalidate(connection); throw e
      case e: Throwable if canRecover(e) => pool.invalidate(connection); failNode(node); apply(attempt + 1)(f)
      case e: Throwable => pool.invalidate(connection); throw e
    }
  }