Add support for opensearch searchable snapshot metrics

.gitignore

@@ -4,3 +4,4 @@ elasticsearch_exporter
 *-stamp
 .tarballs
 /vendor
+.idea

collector/nodes.go

@@ -38,6 +38,7 @@ func getRoles(node NodeStatsNodeResponse) map[string]bool {
 		"data_content":          false,
 		"ml":                    false,
 		"remote_cluster_client": false,
+		"search":                false,
 		"transform":             false,
 		"ingest":                false,
 		"client":                true,
@@ -92,7 +93,7 @@ func createRoleMetric(role string) *nodeMetric {
 }
 
 var (
-	defaultNodeLabels               = []string{"cluster", "host", "name", "es_master_node", "es_data_node", "es_ingest_node", "es_client_node"}
+	defaultNodeLabels               = []string{"cluster", "host", "name", "es_master_node", "es_data_node", "es_ingest_node", "es_client_node", "es_search_node"}
 	defaultRoleLabels               = []string{"cluster", "host", "name"}
 	defaultThreadPoolLabels         = append(defaultNodeLabels, "type")
 	defaultBreakerLabels            = append(defaultNodeLabels, "breaker")
@@ -110,6 +111,7 @@ var (
 			fmt.Sprintf("%t", roles["data"]),
 			fmt.Sprintf("%t", roles["ingest"]),
 			fmt.Sprintf("%t", roles["client"]),
+			fmt.Sprintf("%t", roles["search"]),
 		}
 	}
 	defaultThreadPoolLabelValues = func(cluster string, node NodeStatsNodeResponse, pool string) []string {
@@ -171,6 +173,13 @@ type filesystemIODeviceMetric struct {
 	Labels func(cluster string, node NodeStatsNodeResponse, device string) []string
 }
 
+type fileCacheMetric struct {
+	Type   prometheus.ValueType
+	Desc   *prometheus.Desc
+	Value  func(fileCacheStats NodeStatsFileCacheResponse) float64
+	Labels func(cluster string, node NodeStatsNodeResponse) []string
+}
+
 // Nodes information struct
 type Nodes struct {
 	logger log.Logger
@@ -188,6 +197,7 @@ type Nodes struct {
 	threadPoolMetrics         []*threadPoolMetric
 	filesystemDataMetrics     []*filesystemDataMetric
 	filesystemIODeviceMetrics []*filesystemIODeviceMetric
+	fileCacheMetrics          []*fileCacheMetric
 }
 
 // NewNodes defines Nodes Prometheus metrics
@@ -1781,6 +1791,104 @@ func NewNodes(logger log.Logger, client *http.Client, url *url.URL, all bool, no
 				Labels: defaultFilesystemIODeviceLabelValues,
 			},
 		},
+		fileCacheMetrics: []*fileCacheMetric{
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "active_in_bytes"),
+					"file_cache active memory in bytes",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.ActiveInBytes)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "total_in_bytes"),
+					"file_cache total memory in bytes",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.TotalInBytes)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "used_in_bytes"),
+					"file_cache used memory in bytes",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.UsedInBytes)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "evictions_in_bytes"),
+					"file_cache evicted memory in bytes",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.EvictionsInBytes)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "active_percent"),
+					"file_cache active memory as percent",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.ActivePercent)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "used_percent"),
+					"file_cache used memory as percent",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.UsedPercent)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "hit_count"),
+					"file_cache hit count",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.HitCount)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "filecache", "miss_count"),
+					"file_cache miss count",
+					defaultNodeLabels, nil,
+				),
+				Value: func(fileCacheStats NodeStatsFileCacheResponse) float64 {
+					return float64(fileCacheStats.MissCount)
+				},
+				Labels: defaultNodeLabelValues,
+			},
+		},
 	}
 }
 
@@ -1801,6 +1909,9 @@ func (c *Nodes) Describe(ch chan<- *prometheus.Desc) {
 	for _, metric := range c.filesystemIODeviceMetrics {
 		ch <- metric.Desc
 	}
+	for _, metric := range c.fileCacheMetrics {
+		ch <- metric.Desc
+	}
 	ch <- c.up.Desc()
 	ch <- c.totalScrapes.Desc()
 	ch <- c.jsonParseFailures.Desc()
@@ -1955,5 +2066,16 @@ func (c *Nodes) Collect(ch chan<- prometheus.Metric) {
 			}
 		}
 
+		// File cache Stats
+		for _, metric := range c.fileCacheMetrics {
+			ch <- prometheus.MustNewConstMetric(
+				metric.Desc,
+				metric.Type,
+				metric.Value(node.FileCache),
+				metric.Labels(nodeStatsResp.ClusterName, node)...,
+			)
+		}
+
 	}
+
 }

collector/nodes_response.go

@@ -40,6 +40,7 @@ type NodeStatsNodeResponse struct {
 	HTTP             map[string]interface{}                     `json:"http"`
 	Transport        NodeStatsTransportResponse                 `json:"transport"`
 	Process          NodeStatsProcessResponse                   `json:"process"`
+	FileCache        NodeStatsFileCacheResponse                 `json:"file_cache"`
 }
 
 // NodeStatsBreakersResponse is a representation of a statistics about the field data circuit breaker
@@ -384,3 +385,15 @@ type ClusterHealthResponse struct {
 	TimedOut                bool   `json:"timed_out"`
 	UnassignedShards        int64  `json:"unassigned_shards"`
 }
+
+// NodeStatsFileCacheResponse is a representation of OpenSearch Searchable Snapshots File_cache
+type NodeStatsFileCacheResponse struct {
+	ActiveInBytes    int64 `json:"active_in_bytes"`
+	TotalInBytes     int64 `json:"total_in_bytes"`
+	UsedInBytes      int64 `json:"used_in_bytes"`
+	EvictionsInBytes int64 `json:"evictions_in_bytes"`
+	ActivePercent    int64 `json:"active_percent"`
+	UsedPercent      int64 `json:"used_percent"`
+	HitCount         int64 `json:"hit_count"`
+	MissCount        int64 `json:"miss_count"`
+}