Fallback to Statsig API (#476)

Similar to statsig-io/private-java-server-sdk#284 statsig-io/kong#2405
statsig-io · Jul 31, 2024 · 01df1ea · 01df1ea
1 parent f9db271
commit 01df1ea
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Showing 3 changed files with 50 additions and 20 deletions.
diff --git a/src/StatsigOptions.ts b/src/StatsigOptions.ts
@@ -1,7 +1,6 @@
 import { IDataAdapter } from './interfaces/IDataAdapter';
+import { STATSIG_API, STATSIG_CDN } from './utils/StatsigFetcher';
 
-const DEFAULT_API = 'https://statsigapi.net/v1';
-const DEFAULT_API_FOR_DOWNLOAD_CONFIG_SPECS = 'https://api.statsigcdn.com/v1';
 const DEFAULT_RULESETS_SYNC_INTERVAL = 10 * 1000;
 const MIN_RULESETS_SYNC_INTERVAL = 5 * 1000;
 const DEFAULT_ID_LISTS_SYNC_INTERVAL = 60 * 1000;
@@ -34,6 +33,7 @@ export type ExplicitStatsigOptions = {
   api: string;
   apiForDownloadConfigSpecs: string;
   apiForGetIdLists: string;
+  fallbackToStatsigAPI: boolean;
   bootstrapValues: string | null;
   environment: StatsigEnvironment | null;
   rulesUpdatedCallback: RulesUpdatedCallback | null;
@@ -65,15 +65,16 @@ export function OptionsWithDefaults(
 ): ExplicitStatsigOptions {
   return {
     api: normalizeUrl(
-      getString(opts, 'api', DEFAULT_API) ?? DEFAULT_API,
+      getString(opts, 'api', STATSIG_API) ?? STATSIG_API,
     ) as string,
     apiForDownloadConfigSpecs:
       normalizeUrl(
         getString(opts, 'apiForDownloadConfigSpecs', opts.api ?? null),
-      ) ?? DEFAULT_API_FOR_DOWNLOAD_CONFIG_SPECS,
+      ) ?? STATSIG_CDN,
     apiForGetIdLists:
       normalizeUrl(getString(opts, 'apiForGetIdLists', opts.api ?? null)) ??
-      DEFAULT_API,
+      STATSIG_API,
+    fallbackToStatsigAPI: getBoolean(opts, 'fallbackToStatsigAPI', false),
     bootstrapValues: getString(opts, 'bootstrapValues', null),
     environment: opts.environment
       ? (getObject(opts, 'environment', {}) as StatsigEnvironment)

diff --git a/src/__tests__/CustomDcsUrl.test.ts b/src/__tests__/CustomDcsUrl.test.ts
@@ -22,9 +22,9 @@ describe('Check custom DCS url', () => {
     disableDiagnostics: true,
   });
   const secretKey = 'secret-123';
-  const errorBoundary  = new ErrorBoundary(secretKey, options, "sessionid-1")
+  const errorBoundary = new ErrorBoundary(secretKey, options, 'sessionid-1');
   const fetcher = new StatsigFetcher(secretKey, options);
-  const logger = new LogEventProcessor(fetcher,errorBoundary, options);
+  const logger = new LogEventProcessor(fetcher, errorBoundary, options);
   const store = new SpecStore(fetcher, options);
   Diagnostics.initialize({ logger });
 
@@ -37,7 +37,12 @@ describe('Check custom DCS url', () => {
     logger.log(new LogEvent('test'));
     await logger.flush();
 
-    expect(spy).toHaveBeenCalledWith('GET', customUrl + dcsPath + `/${secretKey}.json?sinceTime=0`, undefined);
+    expect(spy).toHaveBeenCalledWith(
+      'GET',
+      customUrl + dcsPath + `/${secretKey}.json?sinceTime=0`,
+      undefined,
+      undefined,
+    );
     expect(spy).not.toHaveBeenCalledWith(
       'POST',
       customUrl + '/get_id_lists',

diff --git a/src/utils/StatsigFetcher.ts b/src/utils/StatsigFetcher.ts
@@ -14,9 +14,12 @@ import safeFetch from './safeFetch';
 import StatsigContext from './StatsigContext';
 
 const retryStatusCodes = [408, 500, 502, 503, 504, 522, 524, 599];
+export const STATSIG_API = 'https://statsigapi.net/v1';
+export const STATSIG_CDN = 'https://api.statsigcdn.com/v1';
 
 type RequestOptions = Partial<{
   retries: number;
+  retryURL: string;
   backoff: number | RetryBackoffFunc;
   isRetrying: boolean;
   signal: AbortSignal;
@@ -25,9 +28,9 @@ type RequestOptions = Partial<{
 }>;
 
 export default class StatsigFetcher {
-  private api: string;
   private apiForDownloadConfigSpecs: string;
   private apiForGetIdLists: string;
+  private fallbackToStatsigAPI: boolean;
   private sessionID: string;
   private leakyBucket: Record<string, number>;
   private pendingTimers: NodeJS.Timer[];
@@ -42,9 +45,9 @@ export default class StatsigFetcher {
     errorBoundry: ErrorBoundary,
     sessionID: string,
   ) {
-    this.api = options.api;
     this.apiForDownloadConfigSpecs = options.apiForDownloadConfigSpecs;
     this.apiForGetIdLists = options.apiForGetIdLists;
+    this.fallbackToStatsigAPI = options.fallbackToStatsigAPI;
     this.sessionID = sessionID;
     this.leakyBucket = {};
     this.pendingTimers = [];
@@ -66,16 +69,30 @@ export default class StatsigFetcher {
   }
 
   public async downloadConfigSpecs(sinceTime: number): Promise<Response> {
-    return await this.get(
-      this.apiForDownloadConfigSpecs +
-        '/download_config_specs' +
-        `/${this.sdkKey}.json` +
-        `?sinceTime=${sinceTime}`,
-    );
+    const path =
+      '/download_config_specs' +
+      `/${this.sdkKey}.json` +
+      `?sinceTime=${sinceTime}`;
+    const url = this.apiForDownloadConfigSpecs + path;
+
+    let options: RequestOptions | undefined;
+    if (this.fallbackToStatsigAPI) {
+      options = { retries: 1, retryURL: STATSIG_CDN + path };
+    }
+
+    return await this.get(url, options);
   }
 
-  public async getIDLists(sinceTime?: number): Promise<Response> {
-    return await this.post(this.apiForGetIdLists + '/get_id_lists', {});
+  public async getIDLists(): Promise<Response> {
+    const path = '/get_id_lists';
+    const url = this.apiForGetIdLists + path;
+
+    let options: RequestOptions | undefined;
+    if (this.fallbackToStatsigAPI) {
+      options = { retries: 1, retryURL: STATSIG_API + path };
+    }
+
+    return await this.post(url, {}, options);
   }
 
   public dispatch(
@@ -95,7 +112,7 @@ export default class StatsigFetcher {
   }
 
   public async get(url: string, options?: RequestOptions): Promise<Response> {
-    return await this.request('GET', url, options);
+    return await this.request('GET', url, undefined, options);
   }
 
   public async request(
@@ -105,6 +122,7 @@ export default class StatsigFetcher {
     options?: RequestOptions,
   ): Promise<Response> {
     const {
+      retryURL = url,
       retries = 0,
       backoff = 1000,
       isRetrying = false,
@@ -172,7 +190,13 @@ export default class StatsigFetcher {
       .then((localRes) => {
         res = localRes;
         if ((!res.ok || retryStatusCodes.includes(res.status)) && retries > 0) {
-          return this._retry(method, url, body, retries - 1, backoffAdjusted);
+          return this._retry(
+            method,
+            retryURL,
+            body,
+            retries - 1,
+            backoffAdjusted,
+          );
         } else if (!res.ok) {
           return Promise.reject(
             new Error(