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
 
+@xDataType("array")
+@xEnumOptions(["circuit_breaker_triggered", "total_load_time", "eviction_count", "hit_count", "miss_count", "graph_memory_usage", "graph_memory_usage_percentage", "graph_index_requests", "graph_index_errors", "graph_query_requests", "graph_query_errors", "knn_query_requests", "cache_capacity_reached", "load_success_count", "load_exception_count", "indices_in_cache", "script_compilations", "script_compilation_errors", "script_query_requests", "script_query_errors", "nmslib_initialized", "faiss_initialized", "model_index_status", "indexing_from_model_degraded", "training_requests", "training_errors", "training_memory_usage", "training_memory_usage_percentage"])
+@pattern("^(?!_|template|query|field|point|clear|usage|stats|hot|reload|painless).+$")
+@documentation("Comma-separated list of stats to retrieve; use `_all` or empty string to retrieve all stats.")
+string PathStats
+
 @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: PathNodeId,
+}
+
+@input
+structure KNNStats_WithStat_Input with [KNNStats_QueryParams] {
+    @required
+    @httpLabel
+    stat: PathStat,
+}
+
+@input
+structure KNNStats_WithStatNodeId_Input with [KNNStats_QueryParams] {
+    @required
+    @httpLabel
+    nodeId: PathNodeId,
+
+    @required
+    @httpLabel
+    stat: PathStats,
+}
+
+// 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,