[native] Retry feature flags call

Summary:
Retry feature flags call. If number of tries is exceeded, rethrow an error.

Depends on D8652

Test Plan: Add console logs and simulate failed requests - the requests should be retried up to `numberOfTries` times with delays.

Reviewers: kamil, bartek

Reviewed By: bartek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D8679

native/components/feature-flags-provider.react.js

@@ -5,6 +5,7 @@ import * as React from 'react';
 import { Platform } from 'react-native';
 
 import { fetchFeatureFlags } from 'lib/utils/feature-flags-utils.js';
+import sleep from 'lib/utils/sleep.js';
 import { useIsCurrentUserStaff } from 'native/utils/staff-utils.js';
 
 import { codeVersion } from '../redux/persist.js';
@@ -64,11 +65,12 @@ function FeatureFlagsProvider(props: Props): React.Node {
   React.useEffect(() => {
     (async () => {
       try {
-        const config = await fetchFeatureFlags(
-          Platform.OS,
-          isStaff,
-          codeVersion,
+        const config = await tryMultipleTimes(
+          () => fetchFeatureFlags(Platform.OS, isStaff, codeVersion),
+          3,
+          5000,
         );
+
         const configuration = {};
         for (const feature of config.enabledFeatures) {
           configuration[feature] = true;
@@ -94,4 +96,24 @@ function FeatureFlagsProvider(props: Props): React.Node {
   );
 }
 
+async function tryMultipleTimes<T>(
+  f: () => Promise<T>,
+  numberOfTries: number,
+  delay: number,
+): Promise<T> {
+  let lastError;
+  while (numberOfTries > 0) {
+    try {
+      return await f();
+    } catch (e) {
+      --numberOfTries;
+      lastError = e;
+      if (numberOfTries > 0) {
+        await sleep(delay);
+      }
+    }
+  }
+  throw lastError;
+}
+
 export { FeatureFlagsContext, FeatureFlagsProvider, featureFlagsStorageKey };