Zio HTTP Middleware applies to all combined routes

[jwcarvana]

Tapir version: 1.9.9

Scala version: 2.13.12

When combining multiple HttpApp's when using Tapir's ZioHttpInterpreter().toHttp() middleware ends up applying to NotFound handlers. In the following example, three different HttpApps are combined. Visiting a route that 404's causes the Middleware.requestLogging to print three times. I would expect no log lines since zio.http.Server has its own notFound route handler. This only happens when using Tapir.

object BasicServer extends ZIOAppDefault {
  val index = endpoint.get.in("").out(stringBody).zServerLogic(_ => ZIO.succeed("index"))

  val app1 = ZioHttpInterpreter().toHttp(index) @@ Middleware.requestLogging()

  val hello = endpoint.get.in("hello").out(stringBody).zServerLogic(_ => ZIO.succeed("hello"))

  val app2 = ZioHttpInterpreter().toHttp(hello) @@ Middleware.requestLogging()

  val goodbye = endpoint.get.in("goodbye").out(stringBody).zServerLogic(_ => ZIO.succeed("goodbye"))

  val app3 = ZioHttpInterpreter().toHttp(goodbye) @@ Middleware.requestLogging()

  val run =
    Server.serve(app1 ++ app2 ++ app3).provide(Server.default).exitCode
}

Example project: https://github.com/jwcarvana/notfound-middleware-example

[adamw]

The zio-http integration has been quirky before, so not sure if something didn't change as to how we should integrate. But I'm no expert on zio-http codebase, so hard to tell.

Interestingly, if we add a purely zio-http endpoint (e.g. Routes(Method.GET / "c" -> handler(Response.text("Hello World!"))).toHttpApp @@ Middleware.requestLogging()), you only get 1 log entry if you invoke /c, but 3 entries if you invoke a non-existent one.

As a work-around, you can interpret multiple endpoints in one go (it's more efficent, as well):

val index = sttp.tapir.endpoint.get.in("").out(stringBody).zServerLogic[Any](_ => ZIO.succeed("index"))
val hello = sttp.tapir.endpoint.get.in("hello").out(stringBody).zServerLogic[Any](_ => ZIO.succeed("hello"))
val goodbye = sttp.tapir.endpoint.get.in("goodbye").out(stringBody).zServerLogic[Any](_ => ZIO.succeed("goodbye"))

val app = ZioHttpInterpreter().toHttp[Any](List(index, hello, goodbye)) @@ Middleware.requestLogging()