Conditional logging in http4s

logging.scala

package com.byond.infinity.sda

import cats.data.{ Kleisli, OptionT }
import cats.effect.{ Resource, Sync }
import org.http4s.{ HttpRoutes, Response }
import cats.syntax.flatMap._
import org.http4s.client.Client

object logging {
  val log = org.log4s.getLogger

  def logOnError[F[_]]: Response[F] => Boolean = res => !res.status.isSuccess && res.status.code != 404

  def conditionalServerResponseLogger[F[_]](logHeaders: Boolean, logBodyWhen: Response[F] => Boolean = logOnError[F])(
    http: HttpRoutes[F]
  )(implicit F: Sync[F]): HttpRoutes[F] = {
    val logAction: String => F[Unit] = s => F.delay(log.info(s))

    Kleisli { req =>
      http(req).flatTap { res =>
        val logBody = logBodyWhen(res)
        OptionT.liftF(
          org.http4s.internal.Logger
            .logMessage[F, Response[F]](res)(logHeaders, logBody)(logAction)
        )
      }
    }
  }

  def conditionalClientResponseLogger[F[_]](logHeaders: Boolean, logBodyWhen: Response[F] => Boolean = logOnError[F])(
    client: Client[F]
  )(implicit F: Sync[F]): Client[F] = {
    val logAction: String => F[Unit] = s => F.delay(log.info(s))

    Client { req =>
      client.run(req).flatTap { res =>
        val logBody = logBodyWhen(res)
        Resource.liftF(
          org.http4s.internal.Logger
            .logMessage[F, Response[F]](res)(logHeaders, logBody)(logAction)
        )
      }
    }
  }
}