Added spec for k-NN stats api

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

model/common_strings.smithy

@@ -247,6 +247,12 @@ string PathTaskId
 @documentation("The name of the template.")
 string PathTemplateName
 
+@documentation("Comma-separated list of stats to retrieve; use `_all` or empty string to retrieve all stats.")
+string PathStat
+
+@documentation("Comma-separated list of node IDs or names to limit the returned information; use '_local' to return information from the node you're connecting to, leave empty to get information from all nodes.")
+string PathGetNodeId
+
 @documentation("The analyzer to use for the query string.")
 string Analyzer
 

model/knn/stats/operations.smithy

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+//  The OpenSearch Contributors require contributions made to
+//  this file be licensed under the Apache-2.0 license or a
+//  compatible open source license.
+
+$version: "2"
+namespace OpenSearch
+
+@externalDocumentation(
+    "API Reference": "https://opensearch.org/docs/latest/search-plugins/knn/api/#stats"
+)
+
+@xOperationGroup("knn.stats")
+@xVersionAdded("1.0")
+@readonly
+@suppress(["HttpUriConflict"])
+@http(method: "GET", uri: "/_plugins/_knn/stats")
+@documentation("Provides information about the current status of the k-NN plugin.")
+operation KNNStats {
+    input: KNNStats_Input,
+    output: KNNStats_Output
+}
+
+@xOperationGroup("knn.stats")
+@xVersionAdded("1.0")
+@readonly
+@suppress(["HttpUriConflict"])
+@http(method: "GET", uri: "/_plugins/_knn/{nodeId}/stats")
+@documentation("Provides information about the current status of the k-NN plugin.")
+operation KNNStats_WithNodeId {
+    input: KNNStats_WithNodeId_Input,
+    output: KNNStats_Output
+}
+
+@xOperationGroup("knn.stats")
+@xVersionAdded("1.0")
+@readonly
+@suppress(["HttpUriConflict"])
+@http(method: "GET", uri: "/_plugins/_knn/stats/{stat}")
+@documentation("Provides information about the current status of the k-NN plugin.")
+operation KNNStats_WithStat {
+    input: KNNStats_WithStat_Input,
+    output: KNNStats_Output
+}
+
+@xOperationGroup("knn.stats")
+@xVersionAdded("1.0")
+@readonly
+@suppress(["HttpUriConflict"])
+@http(method: "GET", uri: "/_plugins/_knn/{nodeId}/stats/{stat}")
+@documentation("Provides information about the current status of the k-NN plugin.")
+operation KNNStats_WithStatNodeId {
+    input: KNNStats_WithStatNodeId_Input,
+    output: KNNStats_Output
+}

model/knn/stats/structures.smithy

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+//  The OpenSearch Contributors require contributions made to
+//  this file be licensed under the Apache-2.0 license or a
+//  compatible open source license.
+
+$version: "2"
+namespace OpenSearch
+
+@mixin
+structure KNNStats_QueryParams {
+    @httpQuery("timeout")
+    timeout: Timeout,
+}
+
+@input
+structure KNNStats_Input with [KNNStats_QueryParams] {
+}
+
+@input
+structure KNNStats_WithNodeId_Input with [KNNStats_QueryParams] {
+    @required
+    @httpLabel
+    nodeId: PathGetNodeId,
+}
+
+@input
+structure KNNStats_WithStat_Input with [KNNStats_QueryParams] {
+    @required
+    @httpLabel
+    stat: PathStat,
+}
+
+@input
+structure KNNStats_WithStatNodeId_Input with [KNNStats_QueryParams] {
+    @required
+    @httpLabel
+    nodeId: PathGetNodeId,
+
+    @required
+    @httpLabel
+    stat: PathStat,
+}
+
+// TODO: Fill in Output Structure
+structure KNNStats_Output{}

model/opensearch.smithy

@@ -256,6 +256,10 @@ service OpenSearch {
         IngestSimulate_Get_WithId,
         IngestSimulate_Post,
         IngestSimulate_Post_WithId,
+        KNNStats,
+        KNNStats_WithNodeId,
+        KNNStats_WithStat,
+        KNNStats_WithStatNodeId,
         Mget_Get,
         Mget_Get_WithIndex,
         Mget_Post,