Updated SDK’s initial sync to support timeout and retry of segment requests in server-side

CHANGES.txt

@@ -1,4 +1,5 @@
-2.8.1 (November 25, 2025)
+2.9.0 (November 26, 2025)
+ - Updated the SDK’s initial synchronization in Node.js (server-side) to use the `startup.requestTimeoutBeforeReady` and `startup.retriesOnFailureBeforeReady` options to control the timeout and retry behavior of segment requests.
  - Updated the order of storage operations to prevent inconsistent states when using the `LOCALSTORAGE` storage type and the browser’s `localStorage` fails due to quota limits.
 
 2.8.0 (October 30, 2025)

src/sync/polling/syncTasks/segmentsSyncTask.ts

@@ -23,6 +23,8 @@ export function segmentsSyncTaskFactory(
       segmentChangesFetcherFactory(fetchSegmentChanges),
       storage.segments,
       readiness,
+      settings.startup.requestTimeoutBeforeReady,
+      settings.startup.retriesOnFailureBeforeReady,
     ),
     settings.scheduler.segmentsRefreshRate,
     'segmentChangesUpdater'

src/sync/polling/updaters/segmentChangesUpdater.ts

@@ -4,6 +4,7 @@ import { IReadinessManager } from '../../../readiness/types';
 import { SDK_SEGMENTS_ARRIVED } from '../../../readiness/constants';
 import { ILogger } from '../../../logger/types';
 import { LOG_PREFIX_INSTANTIATION, LOG_PREFIX_SYNC_SEGMENTS } from '../../../logger/constants';
+import { timeout } from '../../../utils/promise/timeout';
 
 type ISegmentChangesUpdater = (fetchOnlyNew?: boolean, segmentName?: string, noCache?: boolean, till?: number) => Promise<boolean>
 
@@ -23,25 +24,38 @@ export function segmentChangesUpdaterFactory(
   segmentChangesFetcher: ISegmentChangesFetcher,
   segments: ISegmentsCacheBase,
   readiness?: IReadinessManager,
+  requestTimeoutBeforeReady?: number,
+  retriesOnFailureBeforeReady?: number,
 ): ISegmentChangesUpdater {
 
   let readyOnAlreadyExistentState = true;
 
-  function updateSegment(segmentName: string, noCache?: boolean, till?: number, fetchOnlyNew?: boolean): Promise<boolean> {
+  function _promiseDecorator<T>(promise: Promise<T>) {
+    if (readyOnAlreadyExistentState && requestTimeoutBeforeReady) promise = timeout(requestTimeoutBeforeReady, promise);
+    return promise;
+  }
+
+  function updateSegment(segmentName: string, noCache?: boolean, till?: number, fetchOnlyNew?: boolean, retries?: number): Promise<boolean> {
     log.debug(`${LOG_PREFIX_SYNC_SEGMENTS}Processing segment ${segmentName}`);
     let sincePromise = Promise.resolve(segments.getChangeNumber(segmentName));
 
     return sincePromise.then(since => {
       // if fetchOnlyNew flag, avoid processing already fetched segments
       return fetchOnlyNew && since !== undefined ?
         false :
-        segmentChangesFetcher(since || -1, segmentName, noCache, till).then((changes) => {
+        segmentChangesFetcher(since || -1, segmentName, noCache, till, _promiseDecorator).then((changes) => {
           return Promise.all(changes.map(x => {
             log.debug(`${LOG_PREFIX_SYNC_SEGMENTS}Processing ${segmentName} with till = ${x.till}. Added: ${x.added.length}. Removed: ${x.removed.length}`);
             return segments.update(segmentName, x.added, x.removed, x.till);
           })).then((updates) => {
             return updates.some(update => update);
           });
+        }).catch(error => {
+          if (retries) {
+            log.warn(`${LOG_PREFIX_SYNC_SEGMENTS}Retrying fetch of segment ${segmentName} (attempt #${retries}). Reason: ${error}`);
+            return updateSegment(segmentName, noCache, till, fetchOnlyNew, retries - 1);
+          }
+          throw error;
         });
     });
   }
@@ -63,8 +77,7 @@ export function segmentChangesUpdaterFactory(
     let segmentsPromise = Promise.resolve(segmentName ? [segmentName] : segments.getRegisteredSegments());
 
     return segmentsPromise.then(segmentNames => {
-      // Async fetchers
-      const updaters = segmentNames.map(segmentName => updateSegment(segmentName, noCache, till, fetchOnlyNew));
+      const updaters = segmentNames.map(segmentName => updateSegment(segmentName, noCache, till, fetchOnlyNew, readyOnAlreadyExistentState ? retriesOnFailureBeforeReady : 0));
 
       return Promise.all(updaters).then(shouldUpdateFlags => {
         // if at least one segment fetch succeeded, mark segments ready

src/sync/polling/updaters/splitChangesUpdater.ts

@@ -120,8 +120,8 @@ export function splitChangesUpdaterFactory(
   storage: Pick<IStorageBase, 'splits' | 'rbSegments' | 'segments' | 'save'>,
   splitFiltersValidation: ISplitFiltersValidation,
   splitsEventEmitter?: ISplitsEventEmitter,
-  requestTimeoutBeforeReady: number = 0,
-  retriesOnFailureBeforeReady: number = 0,
+  requestTimeoutBeforeReady = 0,
+  retriesOnFailureBeforeReady = 0,
   isClientSide?: boolean
 ): SplitChangesUpdater {
   const { splits, rbSegments, segments } = storage;
@@ -201,14 +201,13 @@ export function splitChangesUpdaterFactory(
           });
         })
         .catch(error => {
-          log.warn(SYNC_SPLITS_FETCH_FAILS, [error]);
-
           if (startingUp && retriesOnFailureBeforeReady > retry) {
             retry += 1;
-            log.info(SYNC_SPLITS_FETCH_RETRY, [retry, error]);
+            log.warn(SYNC_SPLITS_FETCH_RETRY, [retry, error]);
             return _splitChangesUpdater(sinces, retry);
           } else {
             startingUp = false;
+            log.warn(SYNC_SPLITS_FETCH_FAILS, [error]);
           }
           return false;
         });