Extracting a static redoc site from Tapir

Docs.scala

import java.nio.file.Paths
import cats.effect.{ ExitCode, IO, IOApp }
import DocUtils._
import sttp.tapir.Endpoint

object Docs extends IOApp {

  private val title = "Le API"

  private val version = "1.0"

  // aggregate your endpoints here, no need for the server logic
  private val docEndpoints: List[Endpoint[_, _, _, _]] = ???

  val routes = redocRoutes(title, version, docEndpoints)

  override def run(args: List[String]): IO[ExitCode] = {
    val rootPath = args.headOption.map(Paths.get(_))
    generate(title, version, docEndpoints)
      .flatMap { case (html, yaml) => createFiles(rootPath, html, yaml) }
      .map(_ => ExitCode.Success)
  }
}

DocUtils.scala

import java.nio.file.{ Files, Path, Paths }

import cats.effect.{ ContextShift, IO }
import org.http4s.{ HttpRoutes, Request }
import sttp.tapir.Endpoint
import sttp.tapir.redoc.http4s.RedocHttp4s
import sttp.tapir.openapi.circe.yaml._
import sttp.tapir.docs.openapi._

object DocUtils {
  val yamlFile = "docs.yaml"
  val htmlFile = "index.html"

  type HTML = String
  type Yaml = String

  def redocRoutes(title: String, version: String, endpoints: List[Endpoint[_, _, _, _]])(implicit cs: ContextShift[IO]): HttpRoutes[IO] =
    new RedocHttp4s(title, endpoints.toOpenAPI(title, version).toYaml, yamlFile).routes[IO]

  def generate(title: String, version: String, endpoints: List[Endpoint[_, _, _, _]])(implicit cs: ContextShift[IO]): IO[(HTML, Yaml)] = {
    val yaml   = endpoints.toOpenAPI(title, version).toYaml
    val routes = new RedocHttp4s(title, yaml, yamlFile).routes[IO]
    routes.run(Request()).semiflatMap(_.as[String]).value.map(html => html.get -> yaml)
  }

  def createFiles(rootPath: Option[Path], html: HTML, yaml: Yaml): IO[Unit] =
    for {
      dir <- IO(Files.createDirectories(rootPath.getOrElse(Paths.get("docs"))))
      _   <- IO(Files.write(dir.resolve(htmlFile), html.getBytes))
      _   <- IO(Files.write(dir.resolve(yamlFile), yaml.getBytes))
    } yield ()
}