api: Notify events only if bucket notifications are set. (#2293)

While the existing code worked, it went to an entire cycle
of constructing event structure and end up not sending it.

Avoid this in the first place, but returning quickly if
notifications are not set on the bucket.

queues.go

@@ -112,7 +112,7 @@ func filterRuleMatch(object string, frs []filterRule) bool {
 //  - s3:ObjectCreated:Post
 //  - s3:ObjectCreated:Copy
 //  - s3:ObjectCreated:CompleteMultipartUpload
-func notifyObjectCreatedEvent(nConfig notificationConfig, eventType EventName, bucket string, object string, etag string, size int64) {
+func notifyObjectCreatedEvent(nConfig notificationConfig, eventType EventName, bucket string, objInfo ObjectInfo) {
 	/// Construct a new object created event.
 	region := serverConfig.GetRegion()
 	tnow := time.Now().UTC()
@@ -138,9 +138,9 @@ func notifyObjectCreatedEvent(nConfig notificationConfig, eventType EventName, b
 					ARN:           "arn:aws:s3:::" + bucket,
 				},
 				Object: objectMeta{
-					Key:       url.QueryEscape(object),
-					ETag:      etag,
-					Size:      size,
+					Key:       url.QueryEscape(objInfo.Name),
+					ETag:      objInfo.MD5Sum,
+					Size:      objInfo.Size,
 					Sequencer: sequencer,
 				},
 			},
@@ -148,7 +148,7 @@ func notifyObjectCreatedEvent(nConfig notificationConfig, eventType EventName, b
 	}
 	// Notify to all the configured queues.
 	for _, qConfig := range nConfig.QueueConfigurations {
-		ruleMatch := filterRuleMatch(object, qConfig.Filter.Key.FilterRules)
+		ruleMatch := filterRuleMatch(objInfo.Name, qConfig.Filter.Key.FilterRules)
 		if eventMatch(eventType, qConfig.Events) && ruleMatch {
 			log.WithFields(logrus.Fields{
 				"Records": events,