fix: listenBucket should filter events based on bucket (#8677)

Currently all bucket events are sent to all watchers
with matching prefix and event names, this becomes
problematic and prone to performance issues, fix this
situation by filtering based on buckets as well.

cmd/bucket-notification-handlers.go

@@ -228,6 +228,7 @@ func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWrit
 	bucketName := vars["bucket"]
 
 	values := r.URL.Query()
+	values.Set(peerRESTListenBucket, bucketName)
 
 	var prefix string
 	if len(values[peerRESTListenPrefix]) > 1 {
@@ -295,6 +296,9 @@ func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWrit
 		if !ok {
 			return false
 		}
+		if ev.S3.Bucket.Name != values.Get(peerRESTListenBucket) {
+			return false
+		}
 		objectName, uerr := url.QueryUnescape(ev.S3.Object.Key)
 		if uerr != nil {
 			objectName = ev.S3.Object.Key
@@ -306,7 +310,7 @@ func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWrit
 		if peer == nil {
 			continue
 		}
-		peer.Listen(listenCh, doneCh, r.URL.Query())
+		peer.Listen(listenCh, doneCh, values)
 	}
 
 	keepAliveTicker := time.NewTicker(500 * time.Millisecond)

cmd/peer-rest-common.go

@@ -82,6 +82,7 @@ const (
 	peerRESTTraceAll      = "all"
 	peerRESTTraceErr      = "err"
 
+	peerRESTListenBucket = "bucket"
 	peerRESTListenPrefix = "prefix"
 	peerRESTListenSuffix = "suffix"
 	peerRESTListenEvents = "events"

cmd/peer-rest-server.go

@@ -978,6 +978,9 @@ func (s *peerRESTServer) ListenHandler(w http.ResponseWriter, r *http.Request) {
 		if !ok {
 			return false
 		}
+		if ev.S3.Bucket.Name != values.Get(peerRESTListenBucket) {
+			return false
+		}
 		objectName, uerr := url.QueryUnescape(ev.S3.Object.Key)
 		if uerr != nil {
 			objectName = ev.S3.Object.Key