feat: report feature links by domain (#9936)

src/lib/db/index.ts

@@ -67,6 +67,7 @@ import { UniqueConnectionStore } from '../features/unique-connection/unique-conn
 import { UniqueConnectionReadModel } from '../features/unique-connection/unique-connection-read-model';
 import { FeatureLinkStore } from '../features/feature-links/feature-link-store';
 import { UnknownFlagsStore } from '../features/metrics/unknown-flags/unknown-flags-store';
+import { FeatureLinksReadModel } from '../features/feature-links/feature-links-read-model';
 
 export const createStores = (
     config: IUnleashConfig,
@@ -205,6 +206,7 @@ export const createStores = (
             new ReleasePlanMilestoneStrategyStore(db, config),
         featureLinkStore: new FeatureLinkStore(db, config),
         unknownFlagsStore: new UnknownFlagsStore(db),
+        featureLinkReadModel: new FeatureLinksReadModel(db, eventBus),
     };
 };
 

src/lib/features/feature-links/feature-link.e2e.test.ts

@@ -154,6 +154,11 @@ test('should manage feature links', async () => {
             domain: 'example_another',
         },
     ]);
+    const topDomainsMemoized = await featureLinkReadModel.getTopDomains();
+    expect(topDomainsMemoized).toMatchObject([
+        { domain: 'example_another', count: 1 },
+        { domain: 'example', count: 1 },
+    ]);
 
     const [event1, event2, event3] = await eventStore.getEvents();
     expect([event1, event2, event3]).toMatchObject([

src/lib/features/feature-links/feature-links-read-model.ts

@@ -6,10 +6,15 @@ import type {
 import metricsHelper from '../../util/metrics-helper';
 import { DB_TIME } from '../../metric-events';
 import type EventEmitter from 'events';
+import memoizee from 'memoizee';
+import { hoursToMilliseconds } from 'date-fns';
 
 export class FeatureLinksReadModel implements IFeatureLinksReadModel {
     private db: Db;
     private timer: Function;
+    private _getTopDomainsMemoized: () => Promise<
+        { domain: string; count: number }[]
+    >;
 
     constructor(db: Db, eventBus: EventEmitter) {
         this.db = db;
@@ -18,9 +23,18 @@ export class FeatureLinksReadModel implements IFeatureLinksReadModel {
                 store: 'feature_links',
                 action,
             });
+
+        this._getTopDomainsMemoized = memoizee(this._getTopDomains.bind(this), {
+            promise: true,
+            maxAge: hoursToMilliseconds(1),
+        });
     }
 
-    async getTopDomains(): Promise<{ domain: string; count: number }[]> {
+    public getTopDomains(): Promise<{ domain: string; count: number }[]> {
+        return this._getTopDomainsMemoized();
+    }
+
+    async _getTopDomains(): Promise<{ domain: string; count: number }[]> {
         const stopTimer = this.timer('getTopDomains');
         const topDomains = await this.db
             .from('feature_link')
@@ -29,7 +43,7 @@ export class FeatureLinksReadModel implements IFeatureLinksReadModel {
             .whereNotNull('domain')
             .groupBy('domain')
             .orderBy('count', 'desc')
-            .limit(20);
+            .limit(3);
         stopTimer();
 
         return topDomains.map(({ domain, count }) => ({

src/lib/metrics.ts

@@ -656,6 +656,25 @@ export function registerPrometheusMetrics(
             })),
     });
 
+    dbMetrics.registerGaugeDbMetric({
+        name: 'feature_link_by_domain',
+        help: 'Count most popular domains used in feature links',
+        labelNames: ['domain'],
+        query: () => {
+            if (flagResolver.isEnabled('featureLinks')) {
+                return stores.featureLinkReadModel.getTopDomains();
+            }
+            return Promise.resolve([]);
+        },
+        map: (result) =>
+            result.map(({ domain, count }) => ({
+                value: count,
+                labels: {
+                    domain,
+                },
+            })),
+    });
+
     const featureLifecycleStageEnteredCounter = createCounter({
         name: 'feature_lifecycle_stage_entered',
         help: 'Count how many features entered a given stage',

src/lib/types/stores.ts

@@ -61,6 +61,7 @@ import { ReleasePlanMilestoneStore } from '../features/release-plans/release-pla
 import { ReleasePlanMilestoneStrategyStore } from '../features/release-plans/release-plan-milestone-strategy-store';
 import type { IFeatureLinkStore } from '../features/feature-links/feature-link-store-type';
 import { IUnknownFlagsStore } from '../features/metrics/unknown-flags/unknown-flags-store';
+import { IFeatureLinksReadModel } from '../features/feature-links/feature-links-read-model-type';
 
 export interface IUnleashStores {
     accessStore: IAccessStore;
@@ -126,6 +127,7 @@ export interface IUnleashStores {
     releasePlanMilestoneStrategyStore: ReleasePlanMilestoneStrategyStore;
     featureLinkStore: IFeatureLinkStore;
     unknownFlagsStore: IUnknownFlagsStore;
+    featureLinkReadModel: IFeatureLinksReadModel;
 }
 
 export {
@@ -189,4 +191,5 @@ export {
     ReleasePlanMilestoneStrategyStore,
     type IFeatureLinkStore,
     IUnknownFlagsStore,
+    IFeatureLinksReadModel,
 };

src/test/fixtures/store.ts

@@ -64,6 +64,7 @@ import { FakeUniqueConnectionStore } from '../../lib/features/unique-connection/
 import { UniqueConnectionReadModel } from '../../lib/features/unique-connection/unique-connection-read-model';
 import FakeFeatureLinkStore from '../../lib/features/feature-links/fake-feature-link-store';
 import { FakeUnknownFlagsStore } from '../../lib/features/metrics/unknown-flags/fake-unknown-flags-store';
+import { FakeFeatureLinksReadModel } from '../../lib/features/feature-links/fake-feature-links-read-model';
 
 const db = {
     select: () => ({
@@ -143,6 +144,7 @@ const createStores: () => IUnleashStores = () => {
             {} as ReleasePlanMilestoneStrategyStore,
         featureLinkStore: new FakeFeatureLinkStore(),
         unknownFlagsStore,
+        featureLinkReadModel: new FakeFeatureLinksReadModel(),
     };
 };