Create caches for document encoders

modules/core/src/main/scala/jsonrpclib/Monadic.scala

@@ -31,7 +31,7 @@ object Monadic {
     implicit class MonadicOps[F[_], A](private val fa: F[A]) extends AnyVal {
       def flatMap[B](f: A => F[B])(implicit m: Monadic[F]): F[B] = m.doFlatMap(fa)(f)
       def map[B](f: A => B)(implicit m: Monadic[F]): F[B] = m.doMap(fa)(f)
-      def attempt[B](implicit m: Monadic[F]): F[Either[Throwable, A]] = m.doAttempt(fa)
+      def attempt(implicit m: Monadic[F]): F[Either[Throwable, A]] = m.doAttempt(fa)
       def void(implicit m: Monadic[F]): F[Unit] = m.doVoid(fa)
     }
     implicit class MonadicOpsPure[A](private val a: A) extends AnyVal {

modules/examples/server/src/main/scala/examples/server/ServerMain.scala

@@ -4,8 +4,6 @@ import cats.effect._
 import fs2.io._
 import io.circe.generic.semiauto._
 import io.circe.Codec
-import io.circe.Decoder
-import io.circe.Encoder
 import jsonrpclib.fs2._
 import jsonrpclib.CallId
 import jsonrpclib.Endpoint

modules/smithy4s-tests/src/test/scala/jsonrpclib/smithy4sinterop/TestClientSpec.scala

@@ -8,6 +8,7 @@ import io.circe.Encoder
 import jsonrpclib._
 import jsonrpclib.fs2._
 import test._
+import test.TestServerOperation.GreetError
 import weaver._
 
 import scala.concurrent.duration._
@@ -78,4 +79,47 @@ object TestClientSpec extends SimpleIOSuite {
       expect.same(result.payload.message, "Hello Bob")
     }
   }
+
+  testRes("server returns known error") {
+    implicit val greetInputDecoder: Decoder[GreetInput] = CirceJsonCodec.fromSchema
+    implicit val greetOutputEncoder: Encoder[GreetOutput] = CirceJsonCodec.fromSchema
+    implicit val greetErrorEncoder: Encoder[GreetError] = CirceJsonCodec.fromSchema
+    implicit val errEncoder: ErrorEncoder[GreetError] =
+      err => ErrorPayload(-1, "error", Some(Payload(greetErrorEncoder(err))))
+
+    val endpoint: Endpoint[IO] =
+      Endpoint[IO]("greet").apply[GreetInput, GreetError, GreetOutput](in =>
+        IO.pure(Left(GreetError.notWelcomeError(NotWelcomeError(s"${in.name} is not welcome"))))
+      )
+
+    for {
+      clientSideChannel <- setup(endpoint)
+      clientStub = ClientStub(TestServer, clientSideChannel)
+      result <- clientStub.greet("Bob").attempt.toStream
+    } yield {
+      matches(result) { case Left(t: NotWelcomeError) =>
+        expect.same(t.msg, s"Bob is not welcome")
+      }
+    }
+  }
+
+  testRes("server returns unknown error") {
+    implicit val greetInputDecoder: Decoder[GreetInput] = CirceJsonCodec.fromSchema
+    implicit val greetOutputEncoder: Encoder[GreetOutput] = CirceJsonCodec.fromSchema
+
+    val endpoint: Endpoint[IO] =
+      Endpoint[IO]("greet").simple[GreetInput, GreetOutput](_ => IO.raiseError(new RuntimeException("boom!")))
+
+    for {
+      clientSideChannel <- setup(endpoint)
+      clientStub = ClientStub(TestServer, clientSideChannel)
+      result <- clientStub.greet("Bob").attempt.toStream
+    } yield {
+      matches(result) { case Left(t: ErrorPayload) =>
+        expect.same(t.code, 0) &&
+        expect.same(t.message, "boom!") &&
+        expect.same(t.data, None)
+      }
+    }
+  }
 }

modules/smithy4s/src/main/scala/jsonrpclib/smithy4sinterop/CirceDecoderImpl.scala

@@ -0,0 +1,47 @@
+package jsonrpclib.smithy4sinterop
+
+import io.circe.{Decoder => CirceDecoder, _}
+import smithy4s.codecs.PayloadPath
+import smithy4s.schema.CachedSchemaCompiler
+import smithy4s.Document
+import smithy4s.Document.{Encoder => _, _}
+import smithy4s.Schema
+
+private[smithy4sinterop] class CirceDecoderImpl extends CachedSchemaCompiler[CirceDecoder] {
+  val decoder: CachedSchemaCompiler.DerivingImpl[Decoder] = Document.Decoder
+
+  type Cache = decoder.Cache
+  def createCache(): Cache = decoder.createCache()
+
+  def fromSchema[A](schema: Schema[A], cache: Cache): CirceDecoder[A] =
+    c => {
+      c.as[Json]
+        .map(fromJson(_))
+        .flatMap { d =>
+          decoder
+            .fromSchema(schema, cache)
+            .decode(d)
+            .left
+            .map(e =>
+              DecodingFailure(DecodingFailure.Reason.CustomReason(e.getMessage), c.history ++ toCursorOps(e.path))
+            )
+        }
+    }
+
+  def fromSchema[A](schema: Schema[A]): CirceDecoder[A] = fromSchema(schema, createCache())
+
+  private def toCursorOps(path: PayloadPath): List[CursorOp] =
+    path.segments.map {
+      case PayloadPath.Segment.Label(name) => CursorOp.DownField(name)
+      case PayloadPath.Segment.Index(i)    => CursorOp.DownN(i)
+    }
+
+  private def fromJson(json: Json): Document = json.fold(
+    jsonNull = DNull,
+    jsonBoolean = DBoolean(_),
+    jsonNumber = n => DNumber(n.toBigDecimal.get),
+    jsonString = DString(_),
+    jsonArray = arr => DArray(arr.map(fromJson)),
+    jsonObject = obj => DObject(obj.toMap.view.mapValues(fromJson).toMap)
+  )
+}

modules/smithy4s/src/main/scala/jsonrpclib/smithy4sinterop/CirceEncoderImpl.scala

@@ -0,0 +1,28 @@
+package jsonrpclib.smithy4sinterop
+
+import io.circe.{Encoder => CirceEncoder, _}
+import smithy4s.schema.CachedSchemaCompiler
+import smithy4s.Document
+import smithy4s.Document._
+import smithy4s.Schema
+
+private[smithy4sinterop] class CirceEncoderImpl extends CachedSchemaCompiler[CirceEncoder] {
+  val encoder: CachedSchemaCompiler.DerivingImpl[Encoder] = Document.Encoder
+
+  type Cache = encoder.Cache
+  def createCache(): Cache = encoder.createCache()
+
+  def fromSchema[A](schema: Schema[A], cache: Cache): CirceEncoder[A] =
+    a => documentToJson(encoder.fromSchema(schema, cache).encode(a))
+
+  def fromSchema[A](schema: Schema[A]): CirceEncoder[A] = fromSchema(schema, createCache())
+
+  private val documentToJson: Document => Json = {
+    case DNull            => Json.Null
+    case DString(value)   => Json.fromString(value)
+    case DBoolean(value)  => Json.fromBoolean(value)
+    case DNumber(value)   => Json.fromBigDecimal(value)
+    case DArray(values)   => Json.fromValues(values.map(documentToJson))
+    case DObject(entries) => Json.fromFields(entries.view.mapValues(documentToJson))
+  }
+}

modules/smithy4s/src/main/scala/jsonrpclib/smithy4sinterop/CirceJsonCodec.scala

@@ -1,55 +1,33 @@
 package jsonrpclib.smithy4sinterop
 
 import io.circe._
-import smithy4s.codecs.PayloadPath
-import smithy4s.Document
-import smithy4s.Document.{Decoder => _, _}
+import smithy4s.schema.CachedSchemaCompiler
 import smithy4s.Schema
 
 object CirceJsonCodec {
 
+  object Encoder extends CirceEncoderImpl
+  object Decoder extends CirceDecoderImpl
+
+  object Codec extends CachedSchemaCompiler[Codec] {
+    type Cache = (Encoder.Cache, Decoder.Cache)
+    def createCache(): Cache = (Encoder.createCache(), Decoder.createCache())
+
+    def fromSchema[A](schema: Schema[A]): Codec[A] =
+      io.circe.Codec.from(Decoder.fromSchema(schema), Encoder.fromSchema(schema))
+
+    def fromSchema[A](schema: Schema[A], cache: Cache): Codec[A] =
+      io.circe.Codec.from(
+        Decoder.fromSchema(schema, cache._2),
+        Encoder.fromSchema(schema, cache._1)
+      )
+  }
+
   /** Creates a Circe `Codec[A]` from a Smithy4s `Schema[A]`.
     *
     * This enables encoding values of type `A` to JSON and decoding JSON back into `A`, using the structure defined by
     * the Smithy schema.
     */
-  def fromSchema[A](implicit schema: Schema[A]): Codec[A] = Codec.from(
-    c => {
-      c.as[Json]
-        .map(fromJson)
-        .flatMap { d =>
-          Document
-            .decode[A](d)
-            .left
-            .map(e =>
-              DecodingFailure(DecodingFailure.Reason.CustomReason(e.getMessage), c.history ++ toCursorOps(e.path))
-            )
-        }
-    },
-    a => documentToJson(Document.encode(a))
-  )
-
-  private def toCursorOps(path: PayloadPath): List[CursorOp] =
-    path.segments.map {
-      case PayloadPath.Segment.Label(name) => CursorOp.DownField(name)
-      case PayloadPath.Segment.Index(i)    => CursorOp.DownN(i)
-    }
-
-  private val documentToJson: Document => Json = {
-    case DNull            => Json.Null
-    case DString(value)   => Json.fromString(value)
-    case DBoolean(value)  => Json.fromBoolean(value)
-    case DNumber(value)   => Json.fromBigDecimal(value)
-    case DArray(values)   => Json.fromValues(values.map(documentToJson))
-    case DObject(entries) => Json.fromFields(entries.view.mapValues(documentToJson))
-  }
-
-  private def fromJson(json: Json): Document = json.fold(
-    jsonNull = DNull,
-    jsonBoolean = DBoolean(_),
-    jsonNumber = n => DNumber(n.toBigDecimal.get),
-    jsonString = DString(_),
-    jsonArray = arr => DArray(arr.map(fromJson)),
-    jsonObject = obj => DObject(obj.toMap.view.mapValues(fromJson).toMap)
-  )
+  def fromSchema[A](implicit schema: Schema[A]): Codec[A] =
+    Codec.fromSchema(schema)
 }

modules/smithy4s/src/main/scala/jsonrpclib/smithy4sinterop/ClientStub.scala

@@ -1,8 +1,12 @@
 package jsonrpclib.smithy4sinterop
 
 import io.circe.Codec
+import io.circe.HCursor
 import jsonrpclib.Channel
+import jsonrpclib.ErrorPayload
 import jsonrpclib.Monadic
+import jsonrpclib.Monadic.syntax._
+import jsonrpclib.ProtocolError
 import smithy4s.~>
 import smithy4s.schema._
 import smithy4s.Service
@@ -30,12 +34,13 @@ object ClientStub {
 private class ClientStub[Alg[_[_, _, _, _, _]], F[_]: Monadic](val service: Service[Alg], channel: Channel[F]) {
 
   def compile: service.Impl[F] = {
+    val codecCache = CirceJsonCodec.Codec.createCache()
     val interpreter = new service.FunctorEndpointCompiler[F] {
       def apply[I, E, O, SI, SO](e: service.Endpoint[I, E, O, SI, SO]): I => F[O] = {
         val shapeId = e.id
         val spec = EndpointSpec.fromHints(e.hints).toRight(NotJsonRPCEndpoint(shapeId)).toTry.get
 
-        jsonRPCStub(e, spec)
+        jsonRPCStub(e, spec, codecCache)
       }
     }
 
@@ -44,18 +49,42 @@ private class ClientStub[Alg[_[_, _, _, _, _]], F[_]: Monadic](val service: Serv
 
   def jsonRPCStub[I, E, O, SI, SO](
       smithy4sEndpoint: service.Endpoint[I, E, O, SI, SO],
-      endpointSpec: EndpointSpec
+      endpointSpec: EndpointSpec,
+      codecCache: CirceJsonCodec.Codec.Cache
   ): I => F[O] = {
 
-    implicit val inputCodec: Codec[I] = CirceJsonCodec.fromSchema(smithy4sEndpoint.input)
-    implicit val outputCodec: Codec[O] = CirceJsonCodec.fromSchema(smithy4sEndpoint.output)
+    implicit val inputCodec: Codec[I] = CirceJsonCodec.Codec.fromSchema(smithy4sEndpoint.input, codecCache)
+    implicit val outputCodec: Codec[O] = CirceJsonCodec.Codec.fromSchema(smithy4sEndpoint.output, codecCache)
+
+    def errorResponse(throwable: Throwable, errorCodec: Codec[E]): F[E] = {
+      throwable match {
+        case ErrorPayload(_, _, Some(payload)) =>
+          errorCodec.decodeJson(payload.data) match {
+            case Left(err)    => ProtocolError.ParseError(err.getMessage).raiseError
+            case Right(error) => error.pure
+          }
+        case e: Throwable => e.raiseError
+      }
+    }
 
     endpointSpec match {
       case EndpointSpec.Notification(methodName) =>
         val coerce = coerceUnit[O](smithy4sEndpoint.output)
         channel.notificationStub[I](methodName).andThen(f => Monadic[F].doFlatMap(f)(_ => coerce))
       case EndpointSpec.Request(methodName) =>
-        channel.simpleStub[I, O](methodName)
+        smithy4sEndpoint.error match {
+          case None => channel.simpleStub[I, O](methodName)
+          case Some(errorSchema) =>
+            val errorCodec = CirceJsonCodec.Codec.fromSchema(errorSchema.schema, codecCache)
+            val stub = channel.simpleStub[I, O](methodName)
+            (in: I) =>
+              stub.apply(in).attempt.flatMap {
+                case Right(success) => success.pure
+                case Left(error) =>
+                  errorResponse(error, errorCodec)
+                    .flatMap(e => errorSchema.unliftError(e).raiseError)
+              }
+        }
     }
   }
 

modules/smithy4s/src/main/scala/jsonrpclib/smithy4sinterop/ServerEndpoints.scala

@@ -34,11 +34,12 @@ object ServerEndpoints {
   )(implicit service: Service[Alg], F: Monadic[F]): List[Endpoint[F]] = {
     val transformedService = JsonRpcTransformations.apply(service)
     val interpreter: transformedService.FunctorInterpreter[F] = transformedService.toPolyFunction(impl)
+    val codecCache = CirceJsonCodec.Codec.createCache()
     transformedService.endpoints.toList.flatMap { smithy4sEndpoint =>
       EndpointSpec
         .fromHints(smithy4sEndpoint.hints)
         .map { endpointSpec =>
-          jsonRPCEndpoint(smithy4sEndpoint, endpointSpec, interpreter)
+          jsonRPCEndpoint(smithy4sEndpoint, endpointSpec, interpreter, codecCache)
         }
         .toList
     }
@@ -55,17 +56,19 @@ object ServerEndpoints {
     *   JSON-RPC method name and interaction hints
     * @param impl
     *   Interpreter that executes the Smithy operation in `F`
+    * @param codecCache
+    *   Coche for the schema to codec compilation results
     * @return
     *   A JSON-RPC-compatible `Endpoint[F]`
     */
   private def jsonRPCEndpoint[F[_]: Monadic, Op[_, _, _, _, _], I, E, O, SI, SO](
       smithy4sEndpoint: Smithy4sEndpoint[Op, I, E, O, SI, SO],
       endpointSpec: EndpointSpec,
-      impl: FunctorInterpreter[Op, F]
+      impl: FunctorInterpreter[Op, F],
+      codecCache: CirceJsonCodec.Codec.Cache
   ): Endpoint[F] = {
-
-    implicit val inputCodec: Codec[I] = CirceJsonCodec.fromSchema(smithy4sEndpoint.input)
-    implicit val outputCodec: Codec[O] = CirceJsonCodec.fromSchema(smithy4sEndpoint.output)
+    implicit val inputCodec: Codec[I] = CirceJsonCodec.Codec.fromSchema(smithy4sEndpoint.input, codecCache)
+    implicit val outputCodec: Codec[O] = CirceJsonCodec.Codec.fromSchema(smithy4sEndpoint.output, codecCache)
 
     def errorResponse(throwable: Throwable): F[E] = throwable match {
       case smithy4sEndpoint.Error((_, e)) => e.pure
@@ -86,7 +89,7 @@ object ServerEndpoints {
               impl(op)
             }
           case Some(errorSchema) =>
-            implicit val errorCodec: ErrorEncoder[E] = errorCodecFromSchema(errorSchema)
+            implicit val errorCodec: ErrorEncoder[E] = errorCodecFromSchema(errorSchema, codecCache)
             Endpoint[F](methodName).apply[I, E, O] { (input: I) =>
               val op = smithy4sEndpoint.wrap(input)
               impl(op).attempt.flatMap {
@@ -98,8 +101,8 @@ object ServerEndpoints {
     }
   }
 
-  private def errorCodecFromSchema[A](s: ErrorSchema[A]): ErrorEncoder[A] = {
-    val circeCodec = CirceJsonCodec.fromSchema(s.schema)
+  private def errorCodecFromSchema[A](s: ErrorSchema[A], cache: CirceJsonCodec.Codec.Cache): ErrorEncoder[A] = {
+    val circeCodec = CirceJsonCodec.Codec.fromSchema(s.schema, cache)
     (a: A) =>
       ErrorPayload(
         0,