Add missing documentation for ILM metrics (#892)

* Add missing documentation for ILM metrics

Signed-off-by: Jonathan Ballet <jon@multani.info>

* Document the --es.ilm flag

Signed-off-by: Jonathan Ballet <jon@multani.info>

* Apply suggestions from code review

Signed-off-by: Jonathan Ballet <jon@multani.info>

---------

Signed-off-by: Jonathan Ballet <jon@multani.info>

Author: multani

README.md

@@ -57,6 +57,7 @@ elasticsearch_exporter --help
 | es.indices_settings     | 1.0.4rc1              | If true, query settings stats for all indices in the cluster.                                                                                                                                                                                                                                                                                                                         | false |
 | es.indices_mappings     | 1.2.0                 | If true, query stats for mappings of all indices of the cluster.                                                                                                                                                                                                                                                                                                                      | false |
 | es.aliases              | 1.0.4rc1              | If true, include informational aliases metrics.                                                                                                                                                                                                                                                                                                                                       | true |
+| es.ilm                  | 1.6.0                 | If true, query index lifecycle policies for indices in the cluster.
 | es.shards               | 1.0.3rc1              | If true, query stats for all indices in the cluster, including shard-level stats (implies `es.indices=true`).                                                                                                                                                                                                                                                                         | false |
 | collector.snapshots     | 1.0.4rc1              | If true, query stats for the cluster snapshots. (As of v1.7.0, this flag has replaced "es.snapshots").                                                                                                                                                                                                                                                                                | false |
 | es.slm                  |                       | If true, query stats for SLM.                                                                                                                                                                                                                                                                                                                                                         | false |
@@ -142,6 +143,8 @@ Further Information
 | elasticsearch_filesystem_io_stats_device_write_operations_count      | gauge      | 1           | Count of disk write operations                                                                      |
 | elasticsearch_filesystem_io_stats_device_read_size_kilobytes_sum     | gauge      | 1           | Total kilobytes read from disk                                                                      |
 | elasticsearch_filesystem_io_stats_device_write_size_kilobytes_sum    | gauge      | 1           | Total kilobytes written to disk                                                                     |
+| elasticsearch_ilm_status                                             | gauge      | 1           | Current status of ILM. Status can be `STOPPED`, `RUNNING`, `STOPPING`.                              |
+| elasticsearch_ilm_index_status                                       | gauge      | 4           | Status of ILM policy for index                                                                      |
 | elasticsearch_indices_active_queries                                 | gauge      | 1           | The number of currently active queries                                                              |
 | elasticsearch_indices_docs                                           | gauge      | 1           | Count of documents on this node                                                                     |
 | elasticsearch_indices_docs_deleted                                   | gauge      | 1           | Count of deleted documents on this node                                                             |

collector/ilm_status.go

@@ -62,7 +62,7 @@ func NewIlmStatus(logger *slog.Logger, client *http.Client, url *url.URL) *IlmSt
 			Type: prometheus.GaugeValue,
 			Desc: prometheus.NewDesc(
 				prometheus.BuildFQName(namespace, subsystem, "status"),
-				"Current status of ilm. Status can be STOPPED, RUNNING, STOPPING.",
+				"Current status of ILM. Status can be STOPPED, RUNNING, STOPPING.",
 				[]string{"operation_mode"}, nil,
 			),
 			Value: func(ilm *IlmStatusResponse, status string) float64 {

collector/ilm_status_test.go

@@ -39,7 +39,7 @@ func TestILMStatus(t *testing.T) {
 			name: "6.6.0",
 			file: "../fixtures/ilm_status/6.6.0.json",
 			want: `
-# HELP elasticsearch_ilm_status Current status of ilm. Status can be STOPPED, RUNNING, STOPPING.
+# HELP elasticsearch_ilm_status Current status of ILM. Status can be STOPPED, RUNNING, STOPPING.
 # TYPE elasticsearch_ilm_status gauge
 elasticsearch_ilm_status{operation_mode="RUNNING"} 1
 elasticsearch_ilm_status{operation_mode="STOPPED"} 0

main.go

@@ -82,7 +82,7 @@ func main() {
 			"Export informational alias metrics.").
 			Default("true").Bool()
 		esExportILM = kingpin.Flag("es.ilm",
-			"Export index lifecycle politics for indices in the cluster.").
+			"Export index lifecycle policies for indices in the cluster.").
 			Default("false").Bool()
 		esExportShards = kingpin.Flag("es.shards",
 			"Export stats for shards in the cluster (implies --es.indices).").