Add creation_date metrics

README.md

@@ -187,6 +187,7 @@ Further Information
 | elasticsearch_indices_search_query_total                             | counter    | 1           | Total number of queries                                                                             |
 | elasticsearch_indices_segments_count                                 | gauge      | 1           | Count of index segments on this node                                                                |
 | elasticsearch_indices_segments_memory_bytes                          | gauge      | 1           | Current memory size of segments in bytes                                                            |
+| elasticsearch_indices_settings_creation_timestamp_seconds            | gauge      | 1           | Timestamp of the index creation in seconds                                                                     |
 | elasticsearch_indices_settings_stats_read_only_indices               | gauge      | 1           | Count of indices that have read_only_allow_delete=true                                              |
 | elasticsearch_indices_settings_total_fields                          | gauge      |             | Index setting value for index.mapping.total_fields.limit (total allowable mapped fields in a index) |
 | elasticsearch_indices_settings_replicas                              | gauge      |             | Index setting value for index.replicas                                                              |

collector/indices_settings.go

@@ -43,6 +43,7 @@ type IndicesSettings struct {
 var (
 	defaultIndicesTotalFieldsLabels = []string{"index"}
 	defaultTotalFieldsValue         = 1000 //es default configuration for total fields
+	defaultDateCreation             = 0    //es index default creation date
 )
 
 type indicesSettingsMetric struct {
@@ -105,6 +106,21 @@ func NewIndicesSettings(logger log.Logger, client *http.Client, url *url.URL) *I
 					return val
 				},
 			},
+			{
+				Type: prometheus.GaugeValue,
+				Desc: prometheus.NewDesc(
+					prometheus.BuildFQName(namespace, "indices_settings", "creation_timestamp_seconds"),
+					"index setting creation_date",
+					defaultIndicesTotalFieldsLabels, nil,
+				),
+				Value: func(indexSettings Settings) float64 {
+					val, err := strconv.ParseFloat(indexSettings.IndexInfo.CreationDate, 64)
+					if err != nil {
+						return float64(defaultDateCreation)
+					}
+					return val / 1000.0
+				},
+			},
 		},
 	}
 }

collector/indices_settings_response.go

@@ -31,6 +31,7 @@ type IndexInfo struct {
 	Blocks           Blocks  `json:"blocks"`
 	Mapping          Mapping `json:"mapping"`
 	NumberOfReplicas string  `json:"number_of_replicas"`
+	CreationDate     string  `json:"creation_date"`
 }
 
 // Blocks defines whether current index has read_only_allow_delete enabled