From a47a56d84141c20871f8083f80615a117e459f16 Mon Sep 17 00:00:00 2001
From: Andrei Mihu <andrei@heroiclabs.com>
Date: Fri, 29 Sep 2017 15:34:09 +0100
Subject: [PATCH] Better error responses from runtime RPC or HTTP hooks

---
 CHANGELOG.md               |  1 +
 server/pipeline_runtime.go | 20 +++++++++++++++++---
 server/session_auth.go     | 17 ++++++++++++++++-
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58098f874..fec56804d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ The format is based on [keep a changelog](http://keepachangelog.com/) and this p
 - Increase default maximum length of various name, location, timezone, and other free text fields to 255 characters.
 - Increase default maximum length of storage bucket, collection, and record from 70 to 128 characters.
 - Increase default maximum length of topic room names from 64 to 128 characters.
+- Better error responses when runtime function RPC or HTTP hooks fail or return errors.
 
 ### Fixed
 - Realtime notification routing now correctly resolves connected users.
diff --git a/server/pipeline_runtime.go b/server/pipeline_runtime.go
index c8ad438ed..ca58f4a56 100644
--- a/server/pipeline_runtime.go
+++ b/server/pipeline_runtime.go
@@ -15,9 +15,9 @@
 package server
 
 import (
-	"fmt"
-
+	"github.com/yuin/gopher-lua"
 	"go.uber.org/zap"
+	"strings"
 )
 
 func (p *pipeline) rpc(logger *zap.Logger, session *session, envelope *Envelope) {
@@ -36,7 +36,21 @@ func (p *pipeline) rpc(logger *zap.Logger, session *session, envelope *Envelope)
 	result, fnErr := p.runtime.InvokeFunctionRPC(lf, session.userID, session.handle.Load(), session.expiry, rpcMessage.Payload)
 	if fnErr != nil {
 		logger.Error("Runtime RPC function caused an error", zap.String("id", rpcMessage.Id), zap.Error(fnErr))
-		session.Send(ErrorMessage(envelope.CollationId, RUNTIME_FUNCTION_EXCEPTION, fmt.Sprintf("Runtime function caused an error: %s", fnErr.Error())))
+		if apiErr, ok := fnErr.(*lua.ApiError); ok {
+			msg := apiErr.Object.String()
+			if strings.HasPrefix(msg, lf.Proto.SourceName) {
+				msg = msg[len(lf.Proto.SourceName):]
+				msgParts := strings.SplitN(msg, ": ", 2)
+				if len(msgParts) == 2 {
+					msg = msgParts[1]
+				} else {
+					msg = msgParts[0]
+				}
+			}
+			session.Send(ErrorMessage(envelope.CollationId, RUNTIME_FUNCTION_EXCEPTION, msg))
+		} else {
+			session.Send(ErrorMessage(envelope.CollationId, RUNTIME_FUNCTION_EXCEPTION, fnErr.Error()))
+		}
 		return
 	}
 
diff --git a/server/session_auth.go b/server/session_auth.go
index 213f5f5c8..f65bb5805 100644
--- a/server/session_auth.go
+++ b/server/session_auth.go
@@ -38,6 +38,7 @@ import (
 	"github.com/gorilla/mux"
 	"github.com/gorilla/websocket"
 	"github.com/satori/go.uuid"
+	"github.com/yuin/gopher-lua"
 	"go.uber.org/zap"
 	"golang.org/x/crypto/bcrypt"
 	"nakama/pkg/httputil"
@@ -230,7 +231,21 @@ func (a *authenticationService) configure() {
 		responseData, funError := a.runtime.InvokeFunctionHTTP(fn, uuid.Nil, "", 0, payload)
 		if funError != nil {
 			a.logger.Error("Runtime function caused an error", zap.String("path", path), zap.Error(funError))
-			http.Error(w, fmt.Sprintf("Runtime function caused an error: %s", funError.Error()), 500)
+			if apiErr, ok := funError.(*lua.ApiError); ok {
+				msg := apiErr.Object.String()
+				if strings.HasPrefix(msg, fn.Proto.SourceName) {
+					msg = msg[len(fn.Proto.SourceName):]
+					msgParts := strings.SplitN(msg, ": ", 2)
+					if len(msgParts) == 2 {
+						msg = msgParts[1]
+					} else {
+						msg = msgParts[0]
+					}
+				}
+				http.Error(w, msg, 500)
+			} else {
+				http.Error(w, funError.Error(), 500)
+			}
 			return
 		}
 
-- 
GitLab