Handle not exception errors from the server

lib/grpc/server.ex

@@ -184,12 +184,16 @@ defmodule GRPC.Server do
        ) do
     GRPC.Telemetry.server_span(server, endpoint, func_name, stream, fn ->
       last = fn r, s ->
-        reply = apply(server, func_name, [r, s])
-
-        if res_stream do
-          {:ok, stream}
-        else
-          {:ok, stream, reply}
+        case apply(server, func_name, [r, s]) do
+          %GRPC.RPCError{} = error ->
+            {:error, error}
+
+          reply ->
+            if res_stream do
+              {:ok, stream}
+            else
+              {:ok, stream, reply}
+            end
         end
       end
 

lib/grpc/server/adapters/cowboy/handler.ex

@@ -347,11 +347,8 @@ defmodule GRPC.Server.Adapters.Cowboy.Handler do
     result =
       try do
         case do_call_rpc(server, path, stream) do
-          {:error, _} = err ->
-            err
-
-          _ ->
-            :ok
+          {:error, _} = err -> err
+          _ -> :ok
         end
       catch
         kind, e ->
@@ -361,14 +358,8 @@ defmodule GRPC.Server.Adapters.Cowboy.Handler do
       end
 
     case result do
-      {:error, %GRPC.RPCError{} = e} ->
-        exit({e, ""})
-
-      {:error, %{kind: kind}} ->
-        exit({:handle_error, kind})
-
-      other ->
-        other
+      {:error, %GRPC.RPCError{} = e} -> exit({e, ""})
+      :ok -> :ok
     end
   end
 
@@ -387,8 +378,11 @@ defmodule GRPC.Server.Adapters.Cowboy.Handler do
         GRPC.Server.send_trailers(stream, @default_trailers)
         {:ok, stream}
 
-      error ->
-        error
+      {:error, error = %GRPC.RPCError{message: nil, status: status}} ->
+        {:error, %{error | message: GRPC.Status.status_message(status)}}
+
+      {:error, error = %GRPC.RPCError{}} ->
+        {:error, error}
     end
   end
 
@@ -422,7 +416,7 @@ defmodule GRPC.Server.Adapters.Cowboy.Handler do
     :cowboy_req.reply(200, trailers, req)
   end
 
-  def exit_handler(pid, reason) do
+  defp exit_handler(pid, reason) do
     if Process.alive?(pid) do
       Process.exit(pid, reason)
     end

test/grpc/integration/server_test.exs

@@ -60,6 +60,19 @@ defmodule GRPC.Integration.ServerTest do
       raise "unknown error(This is a test, please ignore it)"
     end
 
+    def say_hello(%{name: "handled error"}, _stream) do
+      %GRPC.RPCError{
+        status: GRPC.Status.unauthenticated(),
+        message: "Please authenticate"
+      }
+    end
+
+    def say_hello(%{name: "handled error without message"}, _stream) do
+      %GRPC.RPCError{
+        status: GRPC.Status.unauthenticated()
+      }
+    end
+
     def say_hello(_req, _stream) do
       raise GRPC.RPCError, status: GRPC.Status.unauthenticated(), message: "Please authenticate"
     end
@@ -172,6 +185,33 @@ defmodule GRPC.Integration.ServerTest do
     end)
   end
 
+  test "return errors for handled errors" do
+    run_server([HelloErrorServer], fn port ->
+      {:ok, channel} = GRPC.Stub.connect("localhost:#{port}")
+      req = Helloworld.HelloRequest.new(name: "handled error")
+      {:error, reply} = channel |> Helloworld.Greeter.Stub.say_hello(req)
+
+      assert %GRPC.RPCError{
+               status: GRPC.Status.unauthenticated(),
+               message: "Please authenticate"
+             } == reply
+    end)
+  end
+
+  test "return errors for handled errors with the default message of the status" do
+    run_server([HelloErrorServer], fn port ->
+      {:ok, channel} = GRPC.Stub.connect("localhost:#{port}")
+      req = Helloworld.HelloRequest.new(name: "handled error without message")
+      {:error, reply} = channel |> Helloworld.Greeter.Stub.say_hello(req)
+
+      assert %GRPC.RPCError{
+               status: GRPC.Status.unauthenticated(),
+               message:
+                 "The request does not have valid authentication credentials for the operation"
+             } == reply
+    end)
+  end
+
   test "returns appropriate error for stream requests" do
     run_server([FeatureErrorServer], fn port ->
       {:ok, channel} = GRPC.Stub.connect("localhost:#{port}")