HelloWorldServer.scala

package zio_grpc.examples.helloworld

import io.grpc.Status
import scalapb.zio_grpc.ServerMain
import scalapb.zio_grpc.ServiceList
import scalapb.zio_grpc.{RequestContext, ZTransform}
import zio._
import zio.console._
import zio.stream._

import io.grpc.examples.helloworld.helloworld.ZioHelloworld.ZGreeter
import io.grpc.examples.helloworld.helloworld.{HelloReply, HelloRequest}

object GreeterImpl extends ZGreeter[ZEnv, Any] {
  def sayHello(
      request: HelloRequest
  ): ZIO[zio.ZEnv, Status, HelloReply] =
    putStrLn(s"Got request: $request") *>
      ZIO.succeed(HelloReply(s"Hello, ${request.name}"))
}

class Logging[R] extends ZTransform[R, Status, R with Has[RequestContext]] {
  def logCause(cause: Cause[Status]): URIO[Has[RequestContext], Unit] = ZIO.effectTotal(println("got error"))
  def accessLog: URIO[Has[RequestContext], Unit]                      = ZIO.effectTotal(println("got request"))

  override def effect[A](io: ZIO[R, Status, A]): ZIO[R with Has[RequestContext], Status, A] =
    io.zipLeft(accessLog).tapCause(logCause)

  override def stream[A](io: ZStream[R, Status, A]): ZStream[R with Has[RequestContext], Status, A] =
    (io ++ ZStream.fromEffect(accessLog).drain).onError(logCause)
}

object HelloWorldServer extends ServerMain {
  def services: ServiceList[zio.ZEnv] = ServiceList.add(GreeterImpl.transform(new Logging))
}