[Alerting] Track fields usage in find api

x-pack/plugins/alerting/server/routes/find_rules.test.ts

@@ -4,7 +4,7 @@
  * 2.0; you may not use this file except in compliance with the Elastic License
  * 2.0.
  */
-
+import { usageCountersServiceMock } from 'src/plugins/usage_collection/server/usage_counters/usage_counters_service.mock';
 import { findRulesRoute } from './find_rules';
 import { httpServiceMock } from 'src/core/server/mocks';
 import { licenseStateMock } from '../lib/license_state.mock';
@@ -145,4 +145,42 @@ describe('findRulesRoute', () => {
 
     expect(verifyApiAccess).toHaveBeenCalledWith(licenseState);
   });
+
+  it('should track calls to deprecated functionality', async () => {
+    const licenseState = licenseStateMock.create();
+    const router = httpServiceMock.createRouter();
+    const mockUsageCountersSetup = usageCountersServiceMock.createSetupContract();
+    const mockUsageCounter = mockUsageCountersSetup.createUsageCounter('test');
+
+    findRulesRoute(router, licenseState, mockUsageCounter);
+
+    const findResult = {
+      page: 1,
+      perPage: 1,
+      total: 0,
+      data: [],
+    };
+    rulesClient.find.mockResolvedValueOnce(findResult);
+
+    const [, handler] = router.get.mock.calls[0];
+    const [context, req, res] = mockHandlerArguments(
+      { rulesClient },
+      {
+        params: {},
+        query: {
+          fields: ['foo', 'bar'],
+          per_page: 1,
+          page: 1,
+          default_search_operator: 'OR',
+        },
+      },
+      ['ok']
+    );
+    await handler(context, req, res);
+    expect(mockUsageCounter.incrementCounter).toHaveBeenCalledWith({
+      counterName: `alertingFieldsUsage`,
+      counterType: 'alertingFieldsUsage',
+      incrementBy: 1,
+    });
+  });
 });

x-pack/plugins/alerting/server/routes/find_rules.ts

@@ -7,6 +7,7 @@
 
 import { omit } from 'lodash';
 import { IRouter } from 'kibana/server';
+import { UsageCounter } from 'src/plugins/usage_collection/server';
 import { schema } from '@kbn/config-schema';
 import { ILicenseState } from '../lib';
 import { FindOptions, FindResult } from '../rules_client';
@@ -107,7 +108,8 @@ const rewriteBodyRes: RewriteResponseCase<FindResult<AlertTypeParams>> = ({
 
 export const findRulesRoute = (
   router: IRouter<AlertingRequestHandlerContext>,
-  licenseState: ILicenseState
+  licenseState: ILicenseState,
+  usageCounter?: UsageCounter
 ) => {
   router.get(
     {
@@ -126,6 +128,14 @@ export const findRulesRoute = (
           search_fields: searchFieldsAsArray(req.query.search_fields),
         });
 
+        if (req.query.fields) {
+          usageCounter?.incrementCounter({
+            counterName: `alertingFieldsUsage`,
+            counterType: 'alertingFieldsUsage',
+            incrementBy: 1,
+          });
+        }
+
         const findResult = await rulesClient.find({ options });
         return res.ok({
           body: rewriteBodyRes(findResult),

x-pack/plugins/alerting/server/routes/index.ts

@@ -38,7 +38,7 @@ export interface RouteOptions {
 }
 
 export function defineRoutes(opts: RouteOptions) {
-  const { router, licenseState, encryptedSavedObjects } = opts;
+  const { router, licenseState, encryptedSavedObjects, usageCounter } = opts;
 
   defineLegacyRoutes(opts);
   createRuleRoute(opts);
@@ -49,7 +49,7 @@ export function defineRoutes(opts: RouteOptions) {
   aggregateRulesRoute(router, licenseState);
   disableRuleRoute(router, licenseState);
   enableRuleRoute(router, licenseState);
-  findRulesRoute(router, licenseState);
+  findRulesRoute(router, licenseState, usageCounter);
   getRuleAlertSummaryRoute(router, licenseState);
   getRuleStateRoute(router, licenseState);
   healthRoute(router, licenseState, encryptedSavedObjects);

x-pack/plugins/alerting/server/routes/legacy/find.test.ts

@@ -160,4 +160,30 @@ describe('findAlertRoute', () => {
     await handler(context, req, res);
     expect(trackLegacyRouteUsage).toHaveBeenCalledWith('find', mockUsageCounter);
   });
+
+  it('should track calls to deprecated functionality', async () => {
+    const licenseState = licenseStateMock.create();
+    const router = httpServiceMock.createRouter();
+    const mockUsageCountersSetup = usageCountersServiceMock.createSetupContract();
+    const mockUsageCounter = mockUsageCountersSetup.createUsageCounter('test');
+
+    findAlertRoute(router, licenseState, mockUsageCounter);
+    const [, handler] = router.get.mock.calls[0];
+    const [context, req, res] = mockHandlerArguments(
+      { rulesClient },
+      {
+        params: {},
+        query: {
+          fields: ['foo', 'bar'],
+        },
+      },
+      ['ok']
+    );
+    await handler(context, req, res);
+    expect(mockUsageCounter.incrementCounter).toHaveBeenCalledWith({
+      counterName: `legacyAlertingFieldsUsage`,
+      counterType: 'alertingFieldsUsage',
+      incrementBy: 1,
+    });
+  });
 });

x-pack/plugins/alerting/server/routes/legacy/find.ts

@@ -82,6 +82,14 @@ export const findAlertRoute = (
           : [query.search_fields];
       }
 
+      if (query.fields) {
+        usageCounter?.incrementCounter({
+          counterName: `legacyAlertingFieldsUsage`,
+          counterType: 'alertingFieldsUsage',
+          incrementBy: 1,
+        });
+      }
+
       const findResult = await rulesClient.find({ options });
       return res.ok({
         body: findResult,