Add GC metrics (#387)

README.md

@@ -286,7 +286,7 @@ Table of exported metrics:
 | logstash_info_pipeline_batch_size | gauge | Number of events to retrieve from the input queue before sending to the filter and output stages. |
 | logstash_info_pipeline_workers | gauge | Number of worker threads that will process pipeline events. |
 | logstash_info_status | counter | A metric with a constant '1' value labeled by status. |
-| logstash_info_up | counter | A metric that returns 1 if the node is up, 0 otherwise. |
+| logstash_info_up | gauge | A metric that returns 1 if the node is up, 0 otherwise. |
 | logstash_stats_events_duration_millis | gauge | Duration of events processing in milliseconds. |
 | logstash_stats_events_filtered | gauge | Number of events filtered out. |
 | logstash_stats_events_in | gauge | Number of events received. |
@@ -302,6 +302,8 @@ Table of exported metrics:
 | logstash_stats_flow_queue_backpressure_lifetime | gauge | Lifetime number of events in the backpressure queue. |
 | logstash_stats_flow_worker_concurrency_current | gauge | Current number of workers. |
 | logstash_stats_flow_worker_concurrency_lifetime | gauge | Lifetime number of workers. |
+| logstash_stats_jvm_gc_collection_count | counter | Count of garbage collection runs for a given JVM memory pool. |
+| logstash_stats_jvm_gc_collection_time_millis_total | counter | Total time spent running garbage collection for a given JVM memory pool. |
 | logstash_stats_jvm_mem_heap_committed_bytes | gauge | Amount of heap memory in bytes that is committed for the Java virtual machine to use. |
 | logstash_stats_jvm_mem_heap_max_bytes | gauge | Maximum amount of heap memory in bytes that can be used for memory management. |
 | logstash_stats_jvm_mem_heap_used_bytes | gauge | Amount of used heap memory in bytes. |

internal/collectors/nodestats/nodestats_collector.go

@@ -39,6 +39,9 @@ type NodestatsCollector struct {
 	JvmMemPoolMaxInBytes       *prometheus.Desc
 	JvmMemPoolCommittedInBytes *prometheus.Desc
 
+	JvmGcCollectionCount        *prometheus.Desc
+	JvmGcCollectionTimeInMillis *prometheus.Desc
+
 	JvmUptimeMillis *prometheus.Desc
 
 	ProcessOpenFileDescriptors    *prometheus.Desc
@@ -108,6 +111,11 @@ func NewNodestatsCollector(clients []logstash_client.Client) *NodestatsCollector
 		JvmMemPoolCommittedInBytes: descHelper.NewDesc("jvm_mem_pool_committed_bytes",
 			"Amount of bytes that are committed for the Java virtual machine to use in a given JVM memory pool.", "pool"),
 
+		JvmGcCollectionCount: descHelper.NewDesc(
+			"jvm_gc_collection_count", "Count of garbage collection runs for a given JVM memory pool.", "pool"),
+		JvmGcCollectionTimeInMillis: descHelper.NewDesc(
+			"jvm_gc_collection_time_millis_total", "Total time spent running garbage collection for a given JVM memory pool.", "pool"),
+
 		JvmUptimeMillis: descHelper.NewDesc("jvm_uptime_millis",
 			"Uptime of the JVM in milliseconds."),
 
@@ -234,6 +242,20 @@ func (collector *NodestatsCollector) collectSingleInstance(client logstash_clien
 	//	  *************************
 	// ********************************
 
+	// ************ GC ************
+	//	  ********* YOUNG *********
+	metricsHelper.Labels = []string{"young", endpoint}
+	metricsHelper.NewIntMetric(collector.JvmGcCollectionCount, prometheus.CounterValue, nodeStats.Jvm.Gc.Collectors.Young.CollectionCount)
+	metricsHelper.NewIntMetric(collector.JvmGcCollectionTimeInMillis, prometheus.CounterValue, nodeStats.Jvm.Gc.Collectors.Young.CollectionTimeInMillis)
+	//	  *************************
+
+	//	  ********* OLD *********
+	metricsHelper.Labels = []string{"old", endpoint}
+	metricsHelper.NewIntMetric(collector.JvmGcCollectionCount, prometheus.CounterValue, nodeStats.Jvm.Gc.Collectors.Old.CollectionCount)
+	metricsHelper.NewIntMetric(collector.JvmGcCollectionTimeInMillis, prometheus.CounterValue, nodeStats.Jvm.Gc.Collectors.Old.CollectionTimeInMillis)
+	//	  *************************
+	// ********************************
+
 	metricsHelper.Labels = []string{endpoint}
 
 	// ************ UPTIME ************

internal/collectors/nodestats/nodestats_collector_test.go

@@ -117,6 +117,8 @@ func TestCollectNotNil(t *testing.T) {
 		"logstash_stats_jvm_mem_pool_peak_max_bytes",
 		"logstash_stats_jvm_mem_pool_max_bytes",
 		"logstash_stats_jvm_mem_pool_committed_bytes",
+		"logstash_stats_jvm_gc_collection_count",
+		"logstash_stats_jvm_gc_collection_time_millis_total",
 	}
 
 	var foundMetrics []string

scripts/snapshots/metric_names.txt

@@ -82,3 +82,5 @@ logstash_stats_flow_worker_concurrency_current
 logstash_stats_flow_worker_concurrency_lifetime
 logstash_stats_pipeline_flow_worker_utilization_current
 logstash_stats_pipeline_flow_worker_utilization_lifetime
+logstash_stats_jvm_gc_collection_count
+logstash_stats_jvm_gc_collection_time_millis_total