Merge pull request #800 from Usiel/usiel/fix-metric-deletion-on-group…

…-delete

Fix metric deletion on group delete

core/internal/httpserver/prometheus.go

@@ -73,6 +73,7 @@ func DeleteConsumerMetrics(cluster, consumer string) {
 	consumerStatusGauge.Delete(labels)
 	consumerPartitionLagGauge.DeletePartialMatch(labels)
 	consumerPartitionCurrentOffset.DeletePartialMatch(labels)
+	partitionStatusGauge.DeletePartialMatch(labels)
 }
 
 // DeleteTopicMetrics deletes all metrics that are labeled with a topic
@@ -92,6 +93,19 @@ func DeleteTopicMetrics(cluster, topic string) {
 	consumerStatusGauge.DeletePartialMatch(labels)
 }
 
+// DeleteConsumerTopicMetrics deletes all metrics that are labeled with the provided consumer group AND topic
+func DeleteConsumerTopicMetrics(cluster, consumer, topic string) {
+	labels := map[string]string{
+		"cluster":        cluster,
+		"consumer_group": consumer,
+		"topic":          topic,
+	}
+
+	partitionStatusGauge.DeletePartialMatch(labels)
+	consumerPartitionCurrentOffset.DeletePartialMatch(labels)
+	consumerPartitionLagGauge.DeletePartialMatch(labels)
+}
+
 func (hc *Coordinator) handlePrometheusMetrics() http.HandlerFunc {
 	promHandler := promhttp.Handler()
 

core/internal/storage/inmemory.go

@@ -667,16 +667,26 @@ func (module *InMemoryStorage) deleteGroup(request *protocol.StorageRequest, req
 	}
 
 	clusterMap.consumerLock.Lock()
+	deleteAllGroupMetrics := true
 	if group, ok := clusterMap.consumer[request.Group]; ok && request.Topic != "" {
 		delete(group.topics, request.Topic)
 		if len(group.topics) == 0 {
 			delete(clusterMap.consumer, request.Group)
+		} else {
+			// The consumer group consumes other topics, thus we need to keep its metrics
+			deleteAllGroupMetrics = false
 		}
 	} else {
 		delete(clusterMap.consumer, request.Group)
 	}
 	clusterMap.consumerLock.Unlock()
-	httpserver.DeleteConsumerMetrics(request.Cluster, request.Group)
+
+	if deleteAllGroupMetrics {
+		httpserver.DeleteConsumerMetrics(request.Cluster, request.Group)
+	} else {
+		// only a specific topic was deleted and the consumer group still exists, thus we delete only a subset of the metrics
+		httpserver.DeleteConsumerTopicMetrics(request.Cluster, request.Group, request.Topic)
+	}
 
 	requestLogger.Debug("ok")
 }