feat: make edge use token's cache (#6893)

## About the changes
This PR removes the feature flag `queryMissingTokens` that was fully
rolled out.
It introduces a new way of checking edgeValidTokens controlled by the
flag `checkEdgeValidTokensFromCache` that relies in the cached data but
hits the DB if needed.

The assumption is that most of the times edge will find tokens in the
cache, except for a few cases in which a new token is queried. From all
tokens we expect at most one to hit the DB and in this case querying a
single token should be better than querying all the tokens.

src/lib/db/api-token-store.ts

@@ -194,10 +194,12 @@ export class ApiTokenStore implements IApiTokenStore {
     }
 
     async get(key: string): Promise<IApiToken> {
+        const stopTimer = this.timer('get-by-secret');
         const row = await this.makeTokenProjectQuery().where(
             'tokens.secret',
             key,
         );
+        stopTimer();
         return toTokens(row)[0];
     }
 

src/lib/features/scheduler/schedule-services.ts

@@ -49,7 +49,7 @@ export const scheduleServices = async (
         apiTokenService.fetchActiveTokens.bind(apiTokenService),
         minutesToMilliseconds(1),
         'fetchActiveTokens',
-        0,
+        0, // no jitter, we need tokens at startup
     );
 
     schedulerService.schedule(

src/lib/middleware/api-token-middleware.ts

@@ -2,7 +2,6 @@ import { ApiTokenType } from '../types/models/api-token';
 import type { IUnleashConfig } from '../types/option';
 import type { IApiRequest, IAuthRequest } from '../routes/unleash-types';
 import type { IUnleashServices } from '../server-impl';
-import type { IFlagContext } from '../types';
 
 const isClientApi = ({ path }) => {
     return path && path.indexOf('/api/client') > -1;
@@ -27,20 +26,6 @@ const isProxyApi = ({ path }) => {
     );
 };
 
-const contextFrom = (
-    req: IAuthRequest<any, any, any, any> | IApiRequest<any, any, any, any>,
-): IFlagContext | undefined => {
-    // this is what we'd get from edge:
-    // req_path: '/api/client/features',
-    // req_user_agent: 'unleash-edge-16.0.4'
-    return {
-        reqPath: req.path,
-        reqUserAgent: req.get ? req.get('User-Agent') ?? '' : '',
-        reqAppName:
-            req.headers?.['unleash-appname'] ?? req.query?.appName ?? '',
-    };
-};
-
 export const TOKEN_TYPE_ERROR_MESSAGE =
     'invalid token: expected a different token type for this endpoint';
 
@@ -70,10 +55,7 @@ const apiAccessMiddleware = (
             const apiToken = req.header('authorization');
             if (!apiToken?.startsWith('user:')) {
                 const apiUser = apiToken
-                    ? await apiTokenService.getUserForToken(
-                          apiToken,
-                          contextFrom(req),
-                      )
+                    ? await apiTokenService.getUserForToken(apiToken)
                     : undefined;
                 const { CLIENT, FRONTEND } = ApiTokenType;
 

src/lib/services/api-token-service.test.ts

@@ -197,17 +197,17 @@ test('getUserForToken should get a user with admin token user id and token name'
     expect(user!.internalAdminTokenUserId).toBe(ADMIN_TOKEN_USER.id);
 });
 
-describe('When token is added by another instance', () => {
-    const setup = (options?: IUnleashOptions) => {
-        const token: IApiTokenCreate = {
-            environment: 'default',
-            projects: ['*'],
-            secret: '*:*:some-random-string',
-            type: ApiTokenType.CLIENT,
-            tokenName: 'new-token-by-another-instance',
-            expiresAt: undefined,
-        };
+describe('API token getTokenWithCache', () => {
+    const token: IApiTokenCreate = {
+        environment: 'default',
+        projects: ['*'],
+        secret: '*:*:some-random-string',
+        type: ApiTokenType.CLIENT,
+        tokenName: 'new-token-by-another-instance',
+        expiresAt: undefined,
+    };
 
+    const setup = (options?: IUnleashOptions) => {
         const config: IUnleashConfig = createTestConfig(options);
         const apiTokenStore = new FakeApiTokenStore();
         const environmentStore = new FakeEnvironmentStore();
@@ -220,60 +220,43 @@ describe('When token is added by another instance', () => {
         return {
             apiTokenService,
             apiTokenStore,
-            token,
         };
     };
-    test('should not return the token when query db flag is disabled', async () => {
-        const { apiTokenService, apiTokenStore, token } = setup();
 
-        // simulate this token being inserted by another instance (apiTokenService does not know about it)
+    test('should return the token and perform only one db query', async () => {
+        const { apiTokenService, apiTokenStore } = setup();
+        const apiTokenStoreGet = jest.spyOn(apiTokenStore, 'get');
+
+        // valid token not present in cache (could be inserted by another instance)
         apiTokenStore.insert(token);
 
-        const found = await apiTokenService.getUserForToken(token.secret);
-        expect(found).toBeUndefined();
-    });
-
-    test('should return the token when query db flag is enabled', async () => {
-        const { apiTokenService, apiTokenStore, token } = setup({
-            experimental: {
-                flags: {
-                    queryMissingTokens: true,
-                },
-            },
-        });
-
-        // simulate this token being inserted by another instance (apiTokenService does not know about it)
-        apiTokenStore.insert(token);
-
-        const found = await apiTokenService.getUserForToken(token.secret);
-        expect(found).toBeDefined();
-        expect(found?.username).toBe(token.tokenName);
+        for (let i = 0; i < 5; i++) {
+            const found = await apiTokenService.getTokenWithCache(token.secret);
+            expect(found).toBeDefined();
+            expect(found?.tokenName).toBe(token.tokenName);
+            expect(found?.createdAt).toBeDefined();
+        }
+        expect(apiTokenStoreGet).toHaveBeenCalledTimes(1);
     });
 
     test('should query the db only once for invalid tokens', async () => {
         jest.useFakeTimers();
-        const { apiTokenService, apiTokenStore } = setup({
-            experimental: {
-                flags: {
-                    queryMissingTokens: true,
-                },
-            },
-        });
+        const { apiTokenService, apiTokenStore } = setup();
         const apiTokenStoreGet = jest.spyOn(apiTokenStore, 'get');
 
         const invalidToken = 'invalid-token';
-        for (let i = 0; i < 10; i++) {
+        for (let i = 0; i < 5; i++) {
             expect(
-                await apiTokenService.getUserForToken(invalidToken),
+                await apiTokenService.getTokenWithCache(invalidToken),
             ).toBeUndefined();
         }
         expect(apiTokenStoreGet).toHaveBeenCalledTimes(1);
 
         // after more than 5 minutes we should be able to query again
         jest.advanceTimersByTime(minutesToMilliseconds(6));
-        for (let i = 0; i < 10; i++) {
+        for (let i = 0; i < 5; i++) {
             expect(
-                await apiTokenService.getUserForToken(invalidToken),
+                await apiTokenService.getTokenWithCache(invalidToken),
             ).toBeUndefined();
         }
         expect(apiTokenStoreGet).toHaveBeenCalledTimes(2);

src/lib/services/api-token-service.ts

@@ -25,13 +25,14 @@ import {
     ApiTokenDeletedEvent,
     ApiTokenUpdatedEvent,
     type IAuditUser,
-    type IFlagContext,
     type IFlagResolver,
     SYSTEM_USER_AUDIT,
 } from '../types';
 import { omitKeys } from '../util';
 import type EventService from '../features/events/event-service';
 import { addMinutes, isPast } from 'date-fns';
+import metricsHelper from '../util/metrics-helper';
+import { FUNCTION_TIME } from '../metric-events';
 
 const resolveTokenPermissions = (tokenType: string) => {
     if (tokenType === ApiTokenType.ADMIN) {
@@ -60,14 +61,14 @@ export class ApiTokenService {
 
     private queryAfter = new Map<string, Date>();
 
-    private initialized = false;
-
     private eventService: EventService;
 
     private lastSeenSecrets: Set<string> = new Set<string>();
 
     private flagResolver: IFlagResolver;
 
+    private timer: Function;
+
     constructor(
         {
             apiTokenStore,
@@ -75,7 +76,7 @@ export class ApiTokenService {
         }: Pick<IUnleashStores, 'apiTokenStore' | 'environmentStore'>,
         config: Pick<
             IUnleashConfig,
-            'getLogger' | 'authentication' | 'flagResolver'
+            'getLogger' | 'authentication' | 'flagResolver' | 'eventBus'
         >,
         eventService: EventService,
     ) {
@@ -94,18 +95,21 @@ export class ApiTokenService {
                 this.initApiTokens(config.authentication.initApiTokens),
             );
         }
+        this.timer = (functionName: string) =>
+            metricsHelper.wrapTimer(config.eventBus, FUNCTION_TIME, {
+                className: 'ApiTokenService',
+                functionName,
+            });
     }
 
     /**
-     * Executed by a scheduler to refresh all active tokens
+     * Called by a scheduler without jitter to refresh all active tokens
      */
     async fetchActiveTokens(): Promise<void> {
         try {
             this.activeTokens = await this.store.getAllActive();
-            this.initialized = true;
-        } finally {
-            // biome-ignore lint/correctness/noUnsafeFinally: We ignored this for eslint. Leaving this here for now, server-impl test fails without it
-            return;
+        } catch (e) {
+            this.logger.warn('Failed to fetch active tokens', e);
         }
     }
 
@@ -113,50 +117,7 @@ export class ApiTokenService {
         return this.store.get(secret);
     }
 
-    async updateLastSeen(): Promise<void> {
-        if (this.lastSeenSecrets.size > 0) {
-            const toStore = [...this.lastSeenSecrets];
-            this.lastSeenSecrets = new Set<string>();
-            await this.store.markSeenAt(toStore);
-        }
-    }
-
-    public async getAllTokens(): Promise<IApiToken[]> {
-        return this.store.getAll();
-    }
-
-    public async getAllActiveTokens(): Promise<IApiToken[]> {
-        if (this.flagResolver.isEnabled('useMemoizedActiveTokens')) {
-            if (!this.initialized) {
-                // unlikely this will happen but nice to have a fail safe
-                this.logger.info('Fetching active tokens before initialized');
-                await this.fetchActiveTokens();
-            }
-            return this.activeTokens;
-        } else {
-            return this.store.getAllActive();
-        }
-    }
-
-    private async initApiTokens(tokens: ILegacyApiTokenCreate[]) {
-        const tokenCount = await this.store.count();
-        if (tokenCount > 0) {
-            return;
-        }
-        try {
-            const createAll = tokens
-                .map(mapLegacyTokenWithSecret)
-                .map((t) => this.insertNewApiToken(t, SYSTEM_USER_AUDIT));
-            await Promise.all(createAll);
-        } catch (e) {
-            this.logger.error('Unable to create initial Admin API tokens');
-        }
-    }
-
-    public async getUserForToken(
-        secret: string,
-        flagContext?: IFlagContext, // temporarily added, expected from the middleware
-    ): Promise<IApiUser | undefined> {
+    async getTokenWithCache(secret: string): Promise<IApiToken | undefined> {
         if (!secret) {
             return undefined;
         }
@@ -178,11 +139,7 @@ export class ApiTokenService {
         }
 
         const nextAllowedQuery = this.queryAfter.get(secret) ?? 0;
-        if (
-            !token &&
-            isPast(nextAllowedQuery) &&
-            this.flagResolver.isEnabled('queryMissingTokens', flagContext)
-        ) {
+        if (!token && isPast(nextAllowedQuery)) {
             if (this.queryAfter.size > 1000) {
                 // establish a max limit for queryAfter size to prevent memory leak
                 this.queryAfter.clear();
@@ -190,12 +147,52 @@ export class ApiTokenService {
             // prevent querying the same invalid secret multiple times. Expire after 5 minutes
             this.queryAfter.set(secret, addMinutes(new Date(), 5));
 
+            const stopCacheTimer = this.timer('getTokenWithCache.query');
             token = await this.store.get(secret);
             if (token) {
                 this.activeTokens.push(token);
             }
+            stopCacheTimer();
         }
 
+        return token;
+    }
+
+    async updateLastSeen(): Promise<void> {
+        if (this.lastSeenSecrets.size > 0) {
+            const toStore = [...this.lastSeenSecrets];
+            this.lastSeenSecrets = new Set<string>();
+            await this.store.markSeenAt(toStore);
+        }
+    }
+
+    public async getAllTokens(): Promise<IApiToken[]> {
+        return this.store.getAll();
+    }
+
+    public async getAllActiveTokens(): Promise<IApiToken[]> {
+        return this.store.getAllActive();
+    }
+
+    private async initApiTokens(tokens: ILegacyApiTokenCreate[]) {
+        const tokenCount = await this.store.count();
+        if (tokenCount > 0) {
+            return;
+        }
+        try {
+            const createAll = tokens
+                .map(mapLegacyTokenWithSecret)
+                .map((t) => this.insertNewApiToken(t, SYSTEM_USER_AUDIT));
+            await Promise.all(createAll);
+        } catch (e) {
+            this.logger.error('Unable to create initial Admin API tokens');
+        }
+    }
+
+    public async getUserForToken(
+        secret: string,
+    ): Promise<IApiUser | undefined> {
+        const token = await this.getTokenWithCache(secret);
         if (token) {
             this.lastSeenSecrets.add(token.secret);
             const apiUser: IApiUser = new ApiUser({

src/lib/services/edge-service.ts

@@ -1,39 +1,83 @@
-import type { IUnleashConfig } from '../types';
+import type { IFlagResolver, IUnleashConfig } from '../types';
 import type { Logger } from '../logger';
 import type { EdgeTokenSchema } from '../openapi/spec/edge-token-schema';
 import { constantTimeCompare } from '../util/constantTimeCompare';
 import type { ValidatedEdgeTokensSchema } from '../openapi/spec/validated-edge-tokens-schema';
 import type { ApiTokenService } from './api-token-service';
+import metricsHelper from '../util/metrics-helper';
+import { FUNCTION_TIME } from '../metric-events';
 
 export default class EdgeService {
     private logger: Logger;
 
     private apiTokenService: ApiTokenService;
 
+    private flagResolver: IFlagResolver;
+
+    private timer: Function;
+
     constructor(
         { apiTokenService }: { apiTokenService: ApiTokenService },
-        { getLogger }: Pick<IUnleashConfig, 'getLogger'>,
+        {
+            getLogger,
+            flagResolver,
+            eventBus,
+        }: Pick<IUnleashConfig, 'getLogger' | 'flagResolver' | 'eventBus'>,
     ) {
         this.logger = getLogger('lib/services/edge-service.ts');
         this.apiTokenService = apiTokenService;
+        this.flagResolver = flagResolver;
+        this.timer = (functionName: string) =>
+            metricsHelper.wrapTimer(eventBus, FUNCTION_TIME, {
+                className: 'EdgeService',
+                functionName,
+            });
     }
 
     async getValidTokens(tokens: string[]): Promise<ValidatedEdgeTokensSchema> {
-        const activeTokens = await this.apiTokenService.getAllActiveTokens();
-        const edgeTokens = tokens.reduce((result: EdgeTokenSchema[], token) => {
-            const dbToken = activeTokens.find((activeToken) =>
-                constantTimeCompare(activeToken.secret, token),
-            );
-            if (dbToken) {
-                result.push({
-                    token: token,
-                    type: dbToken.type,
-                    projects: dbToken.projects,
-                });
+        if (this.flagResolver.isEnabled('checkEdgeValidTokensFromCache')) {
+            const stopTimer = this.timer('validateTokensWithCache');
+            // new behavior: use cached tokens when possible
+            // use the db to fetch the missing ones
+            // cache stores both missing and active so we don't hammer the db
+            const validatedTokens: EdgeTokenSchema[] = [];
+            for (const token of tokens) {
+                const found =
+                    await this.apiTokenService.getTokenWithCache(token);
+                if (found) {
+                    validatedTokens.push({
+                        token: token,
+                        type: found.type,
+                        projects: found.projects,
+                    });
+                }
             }
-            return result;
-        }, []);
-        return { tokens: edgeTokens };
+            stopTimer();
+            return { tokens: validatedTokens };
+        } else {
+            // old behavior: go to the db to fetch all tokens and then filter in memory
+            const stopTimer = this.timer('validateTokensWithoutCache');
+            const activeTokens =
+                await this.apiTokenService.getAllActiveTokens();
+            const edgeTokens = tokens.reduce(
+                (result: EdgeTokenSchema[], token) => {
+                    const dbToken = activeTokens.find((activeToken) =>
+                        constantTimeCompare(activeToken.secret, token),
+                    );
+                    if (dbToken) {
+                        result.push({
+                            token: token,
+                            type: dbToken.type,
+                            projects: dbToken.projects,
+                        });
+                    }
+                    return result;
+                },
+                [],
+            );
+            stopTimer();
+            return { tokens: edgeTokens };
+        }
     }
 }
 

src/lib/types/experimental.ts

@@ -43,6 +43,7 @@ export type IFlagKey =
     | 'displayTrafficDataUsage'
     | 'useMemoizedActiveTokens'
     | 'queryMissingTokens'
+    | 'checkEdgeValidTokensFromCache'
     | 'userAccessUIEnabled'
     | 'disableUpdateMaxRevisionId'
     | 'disablePublishUnannouncedEvents'