Implemented support for configuring a cluster metrics monitor to call cat/indices, and cat/shards. (#479)

Signed-off-by: AWSHurneyt <[email protected]>

Author: AWSHurneyt

src/main/kotlin/org/opensearch/commons/alerting/model/ClusterMetricsInput.kt

@@ -261,6 +261,13 @@ data class ClusterMetricsInput(
         val requiresPathParams: Boolean
     ) {
         BLANK("", "", "", false, false),
+        CAT_INDICES(
+            "/_cat/indices",
+            "/_cat/indices",
+            "",
+            true,
+            false
+        ),
         CAT_PENDING_TASKS(
             "/_cat/pending_tasks",
             "/_cat/pending_tasks",
@@ -275,6 +282,13 @@ data class ClusterMetricsInput(
             true,
             false
         ),
+        CAT_SHARDS(
+            "/_cat/shards",
+            "/_cat/shards",
+            "",
+            true,
+            false
+        ),
         CAT_SNAPSHOTS(
             "/_cat/snapshots",
             "/_cat/snapshots",

src/test/kotlin/org/opensearch/commons/alerting/TestHelpers.kt

@@ -395,7 +395,10 @@ fun randomDocLevelMonitorInput(
 }
 
 fun randomClusterMetricsInput(
-    path: String = ClusterMetricsInput.ClusterMetricType.CLUSTER_HEALTH.defaultPath,
+    path: String = ClusterMetricsInput.ClusterMetricType.values()
+        .filter { it.defaultPath.isNotBlank() && !it.requiresPathParams }
+        .random()
+        .defaultPath,
     pathParams: String = "",
     url: String = ""
 ): ClusterMetricsInput {