From ffa2827ab162b37b75349dda7e73bf873ae1fdca Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Thu, 6 Dec 2018 00:37:59 -0800
Subject: [PATCH] fail fast if two notification queues or inputs are enabled

---
 weed/command/filer_replication.go  | 11 +++++++++++
 weed/notification/configuration.go | 25 ++++++++++++++++++-------
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/weed/command/filer_replication.go b/weed/command/filer_replication.go
index 4ceb5ce4c..087a12059 100644
--- a/weed/command/filer_replication.go
+++ b/weed/command/filer_replication.go
@@ -41,6 +41,17 @@ func runFilerReplicate(cmd *Command, args []string) bool {
 
 	var notificationInput sub.NotificationInput
 
+	enabledInput := ""
+	for _, input := range sub.NotificationInputs {
+		if config.GetBool("notification." + input.GetName() + ".enabled") {
+			if enabledInput == "" {
+				enabledInput = input.GetName()
+			} else {
+				glog.Fatalf("Notification input is enabled for both %s and %s", enabledInput, input.GetName())
+			}
+		}
+	}
+
 	for _, input := range sub.NotificationInputs {
 		if config.GetBool("notification." + input.GetName() + ".enabled") {
 			viperSub := config.Sub("notification." + input.GetName())
diff --git a/weed/notification/configuration.go b/weed/notification/configuration.go
index 1a5dfed75..f34ccf305 100644
--- a/weed/notification/configuration.go
+++ b/weed/notification/configuration.go
@@ -27,15 +27,26 @@ func LoadConfiguration(config *viper.Viper) {
 		return
 	}
 
-	for _, store := range MessageQueues {
-		if config.GetBool(store.GetName() + ".enabled") {
-			viperSub := config.Sub(store.GetName())
-			if err := store.Initialize(viperSub); err != nil {
+	enabledQueue := ""
+	for _, queue := range MessageQueues {
+		if config.GetBool(queue.GetName() + ".enabled") {
+			if enabledQueue == "" {
+				enabledQueue = queue.GetName()
+			} else {
+				glog.Fatalf("Notification message queue is enabled for both %s and %s", enabledQueue, queue.GetName())
+			}
+		}
+	}
+
+	for _, queue := range MessageQueues {
+		if config.GetBool(queue.GetName() + ".enabled") {
+			viperSub := config.Sub(queue.GetName())
+			if err := queue.Initialize(viperSub); err != nil {
 				glog.Fatalf("Failed to initialize notification for %s: %+v",
-					store.GetName(), err)
+					queue.GetName(), err)
 			}
-			Queue = store
-			glog.V(0).Infof("Configure notification message queue for %s", store.GetName())
+			Queue = queue
+			glog.V(0).Infof("Configure notification message queue for %s", queue.GetName())
 			return
 		}
 	}