feat: add exponential backoff and retries for push/send

package.json

@@ -40,11 +40,13 @@
   "homepage": "https://github.com/expo/expo-server-sdk-node#readme",
   "dependencies": {
     "node-fetch": "^2.6.0",
-    "promise-limit": "^2.7.0"
+    "promise-limit": "^2.7.0",
+    "promise-retry": "^2.0.1"
   },
   "devDependencies": {
     "@types/jest": "^27.0.1",
     "@types/node-fetch": "^2.5.12",
+    "@types/promise-retry": "^1.1.3",
     "eslint": "^7.32.0",
     "eslint-config-universe": "^7.0.1",
     "fetch-mock": "^9.11.0",

src/ExpoClient.ts

@@ -4,11 +4,14 @@
  * Use this if you are running Node on your server backend when you are working with Expo
  * https://expo.io
  */
-import * as assert from 'assert';
+import assert from 'assert';
 import { Agent } from 'http';
 import fetch, { Headers, Response as FetchResponse } from 'node-fetch';
-import * as promiseLimit from 'promise-limit';
-import * as zlib from 'zlib';
+import promiseLimit from 'promise-limit';
+import promiseRetry from 'promise-retry';
+import zlib from 'zlib';
+
+import { requestRetryMinTimeout } from './ExpoClientValues';
 
 const BASE_URL = 'https://exp.host';
 const BASE_API_URL = `${BASE_URL}/--/api/v2`;
@@ -74,12 +77,31 @@ export class Expo {
   async sendPushNotificationsAsync(messages: ExpoPushMessage[]): Promise<ExpoPushTicket[]> {
     const actualMessagesCount = Expo._getActualMessageCount(messages);
 
-    const data = await this.requestAsync(`${BASE_API_URL}/push/send`, {
-      httpMethod: 'post',
-      body: messages,
-      shouldCompress(body) {
-        return body.length > 1024;
-      },
+    const data = await this.limitConcurrentRequests(async () => {
+      return await promiseRetry(
+        async (retry): Promise<any> => {
+          try {
+            return await this.requestAsync(`${BASE_API_URL}/push/send`, {
+              httpMethod: 'post',
+              body: messages,
+              shouldCompress(body) {
+                return body.length > 1024;
+              },
+            });
+          } catch (e: any) {
+            // if Expo servers rate limit, retry with exponential backoff
+            if (e.statusCode === 429) {
+              return retry(e);
+            }
+            throw e;
+          }
+        },
+        {
+          retries: 2,
+          factor: 2,
+          minTimeout: requestRetryMinTimeout,
+        }
+      );
     });
 
     if (!Array.isArray(data) || data.length !== actualMessagesCount) {
@@ -211,14 +233,12 @@ export class Expo {
       requestHeaders.set('Content-Type', 'application/json');
     }
 
-    const response = await this.limitConcurrentRequests(() =>
-      fetch(url, {
-        method: options.httpMethod,
-        body: requestBody,
-        headers: requestHeaders,
-        agent: this.httpAgent,
-      })
-    );
+    const response = await fetch(url, {
+      method: options.httpMethod,
+      body: requestBody,
+      headers: requestHeaders,
+      agent: this.httpAgent,
+    });
 
     if (response.status !== 200) {
       const apiError = await this.parseErrorResponseAsync(response);
@@ -236,7 +256,7 @@ export class Expo {
     }
 
     if (result.errors) {
-      const apiError = this.getErrorFromResult(result);
+      const apiError = this.getErrorFromResult(response, result);
       throw apiError;
     }
 
@@ -258,7 +278,7 @@ export class Expo {
       return apiError;
     }
 
-    return this.getErrorFromResult(result);
+    return this.getErrorFromResult(response, result);
   }
 
   private async getTextResponseErrorAsync(response: FetchResponse, text: string): Promise<Error> {
@@ -274,13 +294,14 @@ export class Expo {
    * Returns an error for the first API error in the result, with an optional `others` field that
    * contains any other errors.
    */
-  private getErrorFromResult(result: ApiResult): Error {
+  private getErrorFromResult(response: FetchResponse, result: ApiResult): Error {
     assert(result.errors && result.errors.length > 0, `Expected at least one error from Expo`);
     const [errorData, ...otherErrorData] = result.errors!;
     const error: ExtensibleError = this.getErrorFromResultError(errorData);
     if (otherErrorData.length) {
       error.others = otherErrorData.map((data) => this.getErrorFromResultError(data));
     }
+    error.statusCode = response.status;
     return error;
   }
 

src/ExpoClientValues.ts

@@ -0,0 +1 @@
+export const requestRetryMinTimeout = 1000;

src/__tests__/ExpoClient-test.ts

@@ -2,25 +2,14 @@ import fetch from 'node-fetch';
 
 import ExpoClient, { ExpoPushMessage } from '../ExpoClient';
 
+jest.mock('../ExpoClientValues', () => ({
+  requestRetryMinTimeout: 1,
+}));
+
 afterEach(() => {
   (fetch as any).reset();
 });
 
-test('limits the number of concurrent requests', async () => {
-  (fetch as any).mock('https://exp.host/--/api/v2/push/send', { data: [] });
-  expect((fetch as any).calls().length).toBe(0);
-
-  const client = new ExpoClient({ maxConcurrentRequests: 1 });
-  const sendPromise1 = client.sendPushNotificationsAsync([]);
-  const sendPromise2 = client.sendPushNotificationsAsync([]);
-
-  expect((fetch as any).calls().length).toBe(1);
-  await sendPromise1;
-  expect((fetch as any).calls().length).toBe(2);
-  await sendPromise2;
-  expect((fetch as any).calls().length).toBe(2);
-});
-
 describe('sending push notification messages', () => {
   test('sends requests to the Expo API server without a supplied access token', async () => {
     const mockTickets = [
@@ -187,6 +176,58 @@ describe('sending push notification messages', () => {
       others: expect.arrayContaining([expect.any(Error)]),
     });
   });
+
+  test('handles 429 Too Many Requests by applying exponential backoff', async () => {
+    (fetch as any).mock(
+      'https://exp.host/--/api/v2/push/send',
+      {
+        status: 429,
+        body: {
+          errors: [{ code: 'RATE_LIMIT_ERROR', message: `Rate limit exceeded` }],
+        },
+      },
+      { repeat: 3 }
+    );
+
+    const client = new ExpoClient();
+    const ticketPromise = client.sendPushNotificationsAsync([]);
+
+    const rejection = expect(ticketPromise).rejects;
+    await rejection.toThrowError(`Rate limit exceeded`);
+    await rejection.toMatchObject({ code: 'RATE_LIMIT_ERROR' });
+
+    expect((fetch as any).done()).toBeTruthy();
+  });
+
+  test('handles 429 Too Many Requests and succeeds when a retry succeeds', async () => {
+    const mockTickets = [
+      { status: 'ok', id: 'XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX' },
+      { status: 'ok', id: 'YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYYY' },
+    ];
+    (fetch as any)
+      .mock(
+        'https://exp.host/--/api/v2/push/send',
+        {
+          status: 429,
+          body: {
+            errors: [{ code: 'RATE_LIMIT_ERROR', message: `Rate limit exceeded` }],
+          },
+        },
+        { repeat: 2 }
+      )
+      .mock(
+        'https://exp.host/--/api/v2/push/send',
+        { data: mockTickets },
+        { overwriteRoutes: false }
+      );
+
+    const client = new ExpoClient();
+    await expect(client.sendPushNotificationsAsync([{ to: 'a' }, { to: 'b' }])).resolves.toEqual(
+      mockTickets
+    );
+
+    expect((fetch as any).done()).toBeTruthy();
+  });
 });
 
 describe('retrieving push notification receipts', () => {

tsconfig.json

@@ -6,6 +6,7 @@
     "sourceMap": true,
     "declaration": true,
     "types": ["jest", "node"],
+    "esModuleInterop": true,
     "outDir": "./build",
     "rootDir": "./src",
     "strict": true

yarn.lock

@@ -676,6 +676,18 @@
   resolved "https://registry.yarnpkg.com/@types/prettier/-/prettier-2.3.2.tgz#fc8c2825e4ed2142473b4a81064e6e081463d1b3"
   integrity sha512-eI5Yrz3Qv4KPUa/nSIAi0h+qX0XyewOliug5F2QAtuRg6Kjg6jfmxe1GIwoIRhZspD1A0RP8ANrPwvEXXtRFog==
 
+"@types/promise-retry@^1.1.3":
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/@types/promise-retry/-/promise-retry-1.1.3.tgz#baab427419da9088a1d2f21bf56249c21b3dd43c"
+  integrity sha512-LxIlEpEX6frE3co3vCO2EUJfHIta1IOmhDlcAsR4GMMv9hev1iTI9VwberVGkePJAuLZs5rMucrV8CziCfuJMw==
+  dependencies:
+    "@types/retry" "*"
+
+"@types/retry@*":
+  version "0.12.2"
+  resolved "https://registry.yarnpkg.com/@types/retry/-/retry-0.12.2.tgz#ed279a64fa438bb69f2480eda44937912bb7480a"
+  integrity sha512-XISRgDJ2Tc5q4TRqvgJtzsRkFYNJzZrhTdtMoGVBttwzzQJkPnS3WWTFc7kuDRoPtPakl+T+OfdEUjYJj7Jbow==
+
 "@types/stack-utils@^2.0.0":
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/@types/stack-utils/-/stack-utils-2.0.1.tgz#20f18294f797f2209b5f65c8e3b5c8e8261d127c"
@@ -1314,6 +1326,11 @@ enquirer@^2.3.5:
   dependencies:
     ansi-colors "^4.1.1"
 
+err-code@^2.0.2:
+  version "2.0.3"
+  resolved "https://registry.yarnpkg.com/err-code/-/err-code-2.0.3.tgz#23c2f3b756ffdfc608d30e27c9a941024807e7f9"
+  integrity sha512-2bmlRpNKBxT/CRmPOlyISQpNj+qSeYvcym/uT0Jx2bMOlKLtSy1ZmLuVxSEKKyor/N5yhvp/ZiG1oE3DEYMSFA==
+
 error-ex@^1.3.1:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/error-ex/-/error-ex-1.3.2.tgz#b4ac40648107fdcdcfae242f428bea8a14d4f1bf"
@@ -3158,6 +3175,14 @@ promise-limit@^2.7.0:
   resolved "https://registry.yarnpkg.com/promise-limit/-/promise-limit-2.7.0.tgz#eb5737c33342a030eaeaecea9b3d3a93cb592b26"
   integrity sha512-7nJ6v5lnJsXwGprnGXga4wx6d1POjvi5Qmf1ivTRxTjH4Z/9Czja/UCMLVmB9N93GeWOU93XaFaEt6jbuoagNw==
 
+promise-retry@^2.0.1:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/promise-retry/-/promise-retry-2.0.1.tgz#ff747a13620ab57ba688f5fc67855410c370da22"
+  integrity sha512-y+WKFlBR8BGXnsNlIHFGPZmyDf3DFMoLhaflAnyZgV6rG6xu+JwesTo2Q9R6XwYmtmwAFCkAk3e35jEdoeh/3g==
+  dependencies:
+    err-code "^2.0.2"
+    retry "^0.12.0"
+
 prompts@^2.0.1:
   version "2.4.1"
   resolved "https://registry.yarnpkg.com/prompts/-/prompts-2.4.1.tgz#befd3b1195ba052f9fd2fde8a486c4e82ee77f61"
@@ -3283,6 +3308,11 @@ resolve@^2.0.0-next.3:
     is-core-module "^2.2.0"
     path-parse "^1.0.6"
 
+retry@^0.12.0:
+  version "0.12.0"
+  resolved "https://registry.yarnpkg.com/retry/-/retry-0.12.0.tgz#1b42a6266a21f07421d1b0b54b7dc167b01c013b"
+  integrity sha512-9LkiTwjUh6rT555DtE9rTX+BKByPfrMzEAtnlEtdEwr3Nkffwiihqe2bWADg+OQRjt9gl6ICdmB/ZFDCGAtSow==
+
 reusify@^1.0.4:
   version "1.0.4"
   resolved "https://registry.yarnpkg.com/reusify/-/reusify-1.0.4.tgz#90da382b1e126efc02146e90845a88db12925d76"