[data.search.session] Server telemetry on search sessions (#91256)

* [data.search.session] Server telemetry on search sessions

* Update telemetry mappings

* Added tests and logger

Co-authored-by: Liza K <liza.katz@elastic.co>

x-pack/plugins/data_enhanced/server/collectors/fetch.test.ts

@@ -0,0 +1,94 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import {
+  SharedGlobalConfig,
+  ElasticsearchClient,
+  SavedObjectsErrorHelpers,
+  Logger,
+} from '../../../../../src/core/server';
+import { BehaviorSubject } from 'rxjs';
+import { fetchProvider } from './fetch';
+import { elasticsearchServiceMock } from '../../../../../src/core/server/mocks';
+
+describe('fetchProvider', () => {
+  let fetchFn: any;
+  let esClient: jest.Mocked<ElasticsearchClient>;
+  let mockLogger: Logger;
+
+  beforeEach(async () => {
+    const config$ = new BehaviorSubject<SharedGlobalConfig>({
+      kibana: {
+        index: '123',
+      },
+    } as any);
+    mockLogger = {
+      warn: jest.fn(),
+      debug: jest.fn(),
+    } as any;
+    esClient = elasticsearchServiceMock.createElasticsearchClient();
+    fetchFn = fetchProvider(config$, mockLogger);
+  });
+
+  test('returns when ES returns no results', async () => {
+    esClient.search.mockResolvedValue({
+      statusCode: 200,
+      body: {
+        aggregations: {
+          persisted: {
+            buckets: [],
+          },
+        },
+      },
+    } as any);
+
+    const collRes = await fetchFn({ esClient });
+    expect(collRes.transientCount).toBe(0);
+    expect(collRes.persistedCount).toBe(0);
+    expect(collRes.totalCount).toBe(0);
+    expect(mockLogger.warn).not.toBeCalled();
+  });
+
+  test('returns when ES throws an error', async () => {
+    esClient.search.mockRejectedValue(
+      SavedObjectsErrorHelpers.createTooManyRequestsError('a', 'b')
+    );
+
+    const collRes = await fetchFn({ esClient });
+    expect(collRes.transientCount).toBe(0);
+    expect(collRes.persistedCount).toBe(0);
+    expect(collRes.totalCount).toBe(0);
+    expect(mockLogger.warn).toBeCalledTimes(1);
+  });
+
+  test('returns when ES returns full buckets', async () => {
+    esClient.search.mockResolvedValue({
+      statusCode: 200,
+      body: {
+        aggregations: {
+          persisted: {
+            buckets: [
+              {
+                key_as_string: 'true',
+                doc_count: 10,
+              },
+              {
+                key_as_string: 'false',
+                doc_count: 7,
+              },
+            ],
+          },
+        },
+      },
+    } as any);
+
+    const collRes = await fetchFn({ esClient });
+    expect(collRes.transientCount).toBe(7);
+    expect(collRes.persistedCount).toBe(10);
+    expect(collRes.totalCount).toBe(17);
+  });
+});

x-pack/plugins/data_enhanced/server/collectors/fetch.ts

@@ -0,0 +1,59 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { Observable } from 'rxjs';
+import { first } from 'rxjs/operators';
+import { SearchResponse } from 'elasticsearch';
+import { SharedGlobalConfig, Logger } from 'kibana/server';
+import { CollectorFetchContext } from '../../../../../src/plugins/usage_collection/server';
+import { SEARCH_SESSION_TYPE } from '../../common';
+import { ReportedUsage } from './register';
+
+interface SessionPersistedTermsBucket {
+  key_as_string: 'false' | 'true';
+  doc_count: number;
+}
+
+export function fetchProvider(config$: Observable<SharedGlobalConfig>, logger: Logger) {
+  return async ({ esClient }: CollectorFetchContext): Promise<ReportedUsage> => {
+    try {
+      const config = await config$.pipe(first()).toPromise();
+      const { body: esResponse } = await esClient.search<SearchResponse<unknown>>({
+        index: config.kibana.index,
+        body: {
+          size: 0,
+          aggs: {
+            persisted: {
+              terms: {
+                field: `${SEARCH_SESSION_TYPE}.persisted`,
+              },
+            },
+          },
+        },
+      });
+
+      const { buckets } = esResponse.aggregations.persisted;
+      if (!buckets.length) {
+        return { transientCount: 0, persistedCount: 0, totalCount: 0 };
+      }
+
+      const { transientCount = 0, persistedCount = 0 } = buckets.reduce(
+        (usage: Partial<ReportedUsage>, bucket: SessionPersistedTermsBucket) => {
+          const key = bucket.key_as_string === 'false' ? 'transientCount' : 'persistedCount';
+          return { ...usage, [key]: bucket.doc_count };
+        },
+        {}
+      );
+      const totalCount = transientCount + persistedCount;
+      logger.debug(`fetchProvider | ${persistedCount} persisted | ${transientCount} transient`);
+      return { transientCount, persistedCount, totalCount };
+    } catch (e) {
+      logger.warn(`fetchProvider | error | ${e.message}`);
+      return { transientCount: 0, persistedCount: 0, totalCount: 0 };
+    }
+  };
+}

x-pack/plugins/data_enhanced/server/collectors/index.ts

@@ -0,0 +1,8 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+export { registerUsageCollector } from './register';

x-pack/plugins/data_enhanced/server/collectors/register.ts

@@ -0,0 +1,38 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { PluginInitializerContext, Logger } from 'kibana/server';
+import { UsageCollectionSetup } from 'src/plugins/usage_collection/server';
+import { fetchProvider } from './fetch';
+
+export interface ReportedUsage {
+  transientCount: number;
+  persistedCount: number;
+  totalCount: number;
+}
+
+export async function registerUsageCollector(
+  usageCollection: UsageCollectionSetup,
+  context: PluginInitializerContext,
+  logger: Logger
+) {
+  try {
+    const collector = usageCollection.makeUsageCollector<ReportedUsage>({
+      type: 'search-session',
+      isReady: () => true,
+      fetch: fetchProvider(context.config.legacy.globalConfig$, logger),
+      schema: {
+        transientCount: { type: 'long' },
+        persistedCount: { type: 'long' },
+        totalCount: { type: 'long' },
+      },
+    });
+    usageCollection.registerCollector(collector);
+  } catch (err) {
+    return; // kibana plugin is not enabled (test environment)
+  }
+}

x-pack/plugins/data_enhanced/server/plugin.ts

@@ -24,6 +24,7 @@ import {
 import { getUiSettings } from './ui_settings';
 import type { DataEnhancedRequestHandlerContext } from './type';
 import { ConfigSchema } from '../config';
+import { registerUsageCollector } from './collectors';
 import { SecurityPluginSetup } from '../../security/server';
 
 interface SetupDependencies {
@@ -85,6 +86,10 @@ export class EnhancedDataServerPlugin
     this.sessionService.setup(core, {
       taskManager: deps.taskManager,
     });
+
+    if (deps.usageCollection) {
+      registerUsageCollector(deps.usageCollection, this.initializerContext, this.logger);
+    }
   }
 
   public start(core: CoreStart, { taskManager }: StartDependencies) {

x-pack/plugins/telemetry_collection_xpack/schema/xpack_plugins.json

@@ -3183,6 +3183,19 @@
         }
       }
     },
+    "search-session": {
+      "properties": {
+        "transientCount": {
+          "type": "long"
+        },
+        "persistedCount": {
+          "type": "long"
+        },
+        "totalCount": {
+          "type": "long"
+        }
+      }
+    },
     "security_solution": {
       "properties": {
         "detections": {