feat: stabilize global frontend api cache (#6466)

src/lib/features/segment/fake-segment-read-model.ts

@@ -2,8 +2,10 @@ import { IClientSegment, IFeatureStrategySegment, ISegment } from '../../types';
 import { ISegmentReadModel } from './segment-read-model-type';
 
 export class FakeSegmentReadModel implements ISegmentReadModel {
+    constructor(private segments: ISegment[] = []) {}
+
     async getAll(): Promise<ISegment[]> {
-        return [];
+        return this.segments;
     }
 
     async getAllFeatureStrategySegments(): Promise<IFeatureStrategySegment[]> {
@@ -11,7 +13,7 @@ export class FakeSegmentReadModel implements ISegmentReadModel {
     }
 
     async getActive(): Promise<ISegment[]> {
-        return [];
+        return this.segments;
     }
 
     async getActiveForClient(): Promise<IClientSegment[]> {

src/lib/proxy/client-feature-toggle-read-model-type.ts

@@ -0,0 +1,5 @@
+import { IFeatureToggleClient } from '../types';
+
+export interface IClientFeatureToggleReadModel {
+    getClient(): Promise<Record<string, IFeatureToggleClient[]>>;
+}

src/lib/proxy/client-feature-toggle-read-model.ts

@@ -13,6 +13,7 @@ import Raw = Knex.Raw;
 import metricsHelper from '../util/metrics-helper';
 import { DB_TIME } from '../metric-events';
 import EventEmitter from 'events';
+import { IClientFeatureToggleReadModel } from './client-feature-toggle-read-model-type';
 
 export interface IGetAllFeatures {
     featureQuery?: IFeatureToggleQuery;
@@ -20,7 +21,9 @@ export interface IGetAllFeatures {
     userId?: number;
 }
 
-export default class ClientFeatureToggleReadModel {
+export default class ClientFeatureToggleReadModel
+    implements IClientFeatureToggleReadModel
+{
     private db: Db;
 
     private timer: Function;

src/lib/proxy/fake-client-feature-toggle-read-model.ts

@@ -0,0 +1,16 @@
+import { IFeatureToggleClient } from '../types';
+import { IClientFeatureToggleReadModel } from './client-feature-toggle-read-model-type';
+
+export default class FakeClientFeatureToggleReadModel
+    implements IClientFeatureToggleReadModel
+{
+    constructor(private value: Record<string, IFeatureToggleClient[]>) {}
+
+    getClient(): Promise<Record<string, IFeatureToggleClient[]>> {
+        return Promise.resolve(this.value);
+    }
+
+    setValue(value: Record<string, IFeatureToggleClient[]>) {
+        this.value = value;
+    }
+}

src/lib/proxy/frontend-api-repository.ts

@@ -9,7 +9,7 @@ import { IApiUser } from '../types/api-user';
 import { IUnleashConfig } from '../types';
 import { UnleashEvents } from 'unleash-client';
 import { Logger } from '../logger';
-import { GlobalFrontendApiRepository } from './global-frontend-api-repository';
+import { GlobalFrontendApiCache } from './global-frontend-api-cache';
 
 type Config = Pick<IUnleashConfig, 'getLogger'>;
 
@@ -23,13 +23,13 @@ export class FrontendApiRepository
 
     private readonly token: IApiUser;
 
-    private globalFrontendApiRepository: GlobalFrontendApiRepository;
+    private globalFrontendApiRepository: GlobalFrontendApiCache;
 
     private running: boolean;
 
     constructor(
         config: Config,
-        globalFrontendApiRepository: GlobalFrontendApiRepository,
+        globalFrontendApiRepository: GlobalFrontendApiCache,
         token: IApiUser,
     ) {
         super();

src/lib/proxy/global-frontend-api-cache.test.ts

@@ -0,0 +1,169 @@
+import {
+    GlobalFrontendApiCache,
+    GlobalFrontendApiCacheState,
+} from './global-frontend-api-cache';
+import noLogger from '../../test/fixtures/no-logger';
+import { FakeSegmentReadModel } from '../features/segment/fake-segment-read-model';
+import FakeClientFeatureToggleReadModel from './fake-client-feature-toggle-read-model';
+import EventEmitter from 'events';
+import { IApiUser, IFeatureToggleClient, ISegment } from '../types';
+import { UPDATE_REVISION } from '../features/feature-toggle/configuration-revision-service';
+
+const state = async (
+    cache: GlobalFrontendApiCache,
+    state: GlobalFrontendApiCacheState,
+) => {
+    await new Promise((resolve) => {
+        cache.on(state, () => {
+            resolve('done');
+        });
+    });
+};
+
+const defaultFeature: IFeatureToggleClient = {
+    name: 'featureA',
+    enabled: true,
+    strategies: [],
+    variants: [],
+    project: 'projectA',
+    dependencies: [],
+    type: 'release',
+    stale: false,
+    description: '',
+};
+const defaultSegment = { name: 'segment', id: 1 } as ISegment;
+
+const createCache = (
+    segment: ISegment = defaultSegment,
+    features: Record<string, IFeatureToggleClient[]> = {},
+) => {
+    const config = { getLogger: noLogger };
+    const segmentReadModel = new FakeSegmentReadModel([segment as ISegment]);
+    const clientFeatureToggleReadModel = new FakeClientFeatureToggleReadModel(
+        features,
+    );
+    const configurationRevisionService = new EventEmitter();
+    const cache = new GlobalFrontendApiCache(
+        config,
+        segmentReadModel,
+        clientFeatureToggleReadModel,
+        configurationRevisionService,
+    );
+
+    return {
+        cache,
+        configurationRevisionService,
+        clientFeatureToggleReadModel,
+    };
+};
+
+test('Can read initial segment', async () => {
+    const { cache } = createCache({ name: 'segment', id: 1 } as ISegment);
+
+    const segmentBeforeRead = cache.getSegment(1);
+    expect(segmentBeforeRead).toEqual(undefined);
+
+    await state(cache, 'ready');
+
+    const segment = cache.getSegment(1);
+    expect(segment).toEqual({ name: 'segment', id: 1 });
+});
+
+test('Can read initial features', async () => {
+    const { cache } = createCache(defaultSegment, {
+        development: [
+            {
+                ...defaultFeature,
+                name: 'featureA',
+                enabled: true,
+                project: 'projectA',
+            },
+            {
+                ...defaultFeature,
+                name: 'featureB',
+                enabled: true,
+                project: 'projectB',
+            },
+        ],
+        production: [
+            {
+                ...defaultFeature,
+                name: 'featureA',
+                enabled: false,
+                project: 'projectA',
+            },
+        ],
+    });
+
+    const featuresBeforeRead = cache.getToggles({
+        environment: 'development',
+        projects: ['projectA'],
+    } as IApiUser);
+    expect(featuresBeforeRead).toEqual([]);
+
+    await state(cache, 'ready');
+
+    const features = cache.getToggles({
+        environment: 'development',
+        projects: ['projectA'],
+    } as IApiUser);
+    expect(features).toEqual([
+        {
+            ...defaultFeature,
+            name: 'featureA',
+            enabled: true,
+            impressionData: false,
+        },
+    ]);
+
+    const allProjectFeatures = cache.getToggles({
+        environment: 'development',
+        projects: ['*'],
+    } as IApiUser);
+    expect(allProjectFeatures.length).toBe(2);
+
+    const defaultProjectFeatures = cache.getToggles({
+        environment: '*',
+        projects: ['*'],
+    } as IApiUser);
+    expect(defaultProjectFeatures.length).toBe(0);
+});
+
+test('Can refresh data on revision update', async () => {
+    const {
+        cache,
+        configurationRevisionService,
+        clientFeatureToggleReadModel,
+    } = createCache();
+
+    await state(cache, 'ready');
+
+    clientFeatureToggleReadModel.setValue({
+        development: [
+            {
+                ...defaultFeature,
+                name: 'featureA',
+                enabled: false,
+                strategies: [{ name: 'default' }],
+                project: 'projectA',
+            },
+        ],
+    });
+    configurationRevisionService.emit(UPDATE_REVISION);
+
+    await state(cache, 'updated');
+
+    const features = cache.getToggles({
+        environment: 'development',
+        projects: ['projectA'],
+    } as IApiUser);
+    expect(features).toMatchObject([
+        {
+            ...defaultFeature,
+            name: 'featureA',
+            enabled: false,
+            strategies: [{ name: 'default' }],
+            impressionData: false,
+        },
+    ]);
+});

src/lib/proxy/global-frontend-api-cache.ts

@@ -9,38 +9,36 @@ import {
 } from '../features/playground/offline-unleash-client';
 import { ALL_ENVS } from '../util/constants';
 import { Logger } from '../logger';
-import ConfigurationRevisionService, {
-    UPDATE_REVISION,
-} from '../features/feature-toggle/configuration-revision-service';
-import ClientFeatureToggleReadModel from './client-feature-toggle-read-model';
+import { UPDATE_REVISION } from '../features/feature-toggle/configuration-revision-service';
 import { mapValues } from '../util';
+import { IClientFeatureToggleReadModel } from './client-feature-toggle-read-model-type';
 
-type Config = Pick<IUnleashConfig, 'getLogger' | 'frontendApi' | 'eventBus'>;
+type Config = Pick<IUnleashConfig, 'getLogger'>;
 
-export class GlobalFrontendApiRepository extends EventEmitter {
+export type GlobalFrontendApiCacheState = 'starting' | 'ready' | 'updated';
+
+export class GlobalFrontendApiCache extends EventEmitter {
     private readonly config: Config;
 
     private readonly logger: Logger;
 
-    private readonly clientFeatureToggleReadModel: ClientFeatureToggleReadModel;
+    private readonly clientFeatureToggleReadModel: IClientFeatureToggleReadModel;
 
     private readonly segmentReadModel: ISegmentReadModel;
 
-    private readonly configurationRevisionService: ConfigurationRevisionService;
+    private readonly configurationRevisionService: EventEmitter;
 
-    private featuresByEnvironment: Record<string, FeatureInterface[]>;
+    private featuresByEnvironment: Record<string, FeatureInterface[]> = {};
 
-    private segments: Segment[];
+    private segments: Segment[] = [];
 
-    private interval: number;
-
-    private running: boolean;
+    private status: GlobalFrontendApiCacheState = 'starting';
 
     constructor(
         config: Config,
         segmentReadModel: ISegmentReadModel,
-        clientFeatureToggleReadModel: ClientFeatureToggleReadModel,
-        configurationRevisionService: ConfigurationRevisionService,
+        clientFeatureToggleReadModel: IClientFeatureToggleReadModel,
+        configurationRevisionService: EventEmitter,
     ) {
         super();
         this.config = config;
@@ -49,7 +47,6 @@ export class GlobalFrontendApiRepository extends EventEmitter {
         this.configurationRevisionService = configurationRevisionService;
         this.segmentReadModel = segmentReadModel;
         this.onUpdateRevisionEvent = this.onUpdateRevisionEvent.bind(this);
-        this.interval = config.frontendApi.refreshIntervalInMs;
         this.refreshData();
         this.configurationRevisionService.on(
             UPDATE_REVISION,
@@ -62,6 +59,11 @@ export class GlobalFrontendApiRepository extends EventEmitter {
     }
 
     getToggles(token: IApiUser): FeatureInterface[] {
+        if (
+            this.featuresByEnvironment[this.environmentNameForToken(token)] ==
+            null
+        )
+            return [];
         return this.featuresByEnvironment[
             this.environmentNameForToken(token)
         ].filter(
@@ -88,6 +90,13 @@ export class GlobalFrontendApiRepository extends EventEmitter {
         try {
             this.featuresByEnvironment = await this.getAllFeatures();
             this.segments = await this.getAllSegments();
+            if (this.status === 'starting') {
+                this.status = 'ready';
+                this.emit('ready');
+            } else if (this.status === 'ready' || this.status === 'updated') {
+                this.status = 'updated';
+                this.emit('updated');
+            }
         } catch (e) {
             this.logger.error('Cannot load data for token', e);
         }