[sitecore-jss] Optimize initial Retry delay time (#1733)

* update delay time to start from 1ms

* add tests for DefaultRetryStrategy class

* change test description

* update changelog

* update pretierignore

* remove only

* add more unit tests, make defaultStrategy class constructor an object

* add test for default case

CHANGELOG.md

@@ -7,7 +7,7 @@ This project does NOT adhere to [Semantic Versioning](https://semver.org/spec/v2
 
 ### 🎉 New Features & Improvements
 
-* `[sitecore-jss]` Retry policy to handle transient network errors. Users can pass `retryStrategy` to configure custom retry config to the services. They can customize the error codes and the number of retries. It consist of two functions shouldRetry and getDelay. ([#1731](https://github.com/Sitecore/jss/pull/1731))
+* `[sitecore-jss]` Retry policy to handle transient network errors. Users can pass `retryStrategy` to configure custom retry config to the services. They can customize the error codes and the number of retries. It consist of two functions shouldRetry and getDelay. To determine the back-off time, we employ an exponential strategy with a default factor of 2.([#1731](https://github.com/Sitecore/jss/pull/1731)) ([#1733](https://github.com/Sitecore/jss/pull/1733))
 
 ## 20.2.3
 

packages/sitecore-jss/src/graphql-request-client.test.ts

@@ -4,7 +4,8 @@ import { expect, use, spy } from 'chai';
 import sinon from 'sinon';
 import spies from 'chai-spies';
 import nock from 'nock';
-import { GraphQLRequestClient } from './graphql-request-client';
+import { GraphQLRequestClient, DefaultRetryStrategy } from './graphql-request-client';
+import { ClientError } from 'graphql-request';
 import debugApi from 'debug';
 import debug from './debug';
 
@@ -391,4 +392,56 @@ describe('GraphQLRequestClient', () => {
       }
     });
   });
+
+  describe('DefaultRetryStrategy', () => {
+    const mockClientError = new ClientError(
+      {
+        data: undefined,
+        errors: [{ message: 'GaphqlError' }],
+        extensions: undefined,
+        status: 429,
+      },
+      {
+        query: 'query',
+      }
+    );
+    it('should return true from shouldRetry and use default values from constructor', () => {
+      const retryStrategy = new DefaultRetryStrategy();
+
+      const shouldRetry = retryStrategy.shouldRetry(mockClientError, 1, 3);
+      expect(shouldRetry).to.equal(true);
+    });
+
+    it('should return false when attempt exceeds retries', () => {
+      const retryStrategy = new DefaultRetryStrategy({ statusCodes: [503] });
+      mockClientError.response.status = 503;
+
+      const shouldRetry = retryStrategy.shouldRetry(mockClientError, 2, 1);
+      expect(shouldRetry).to.equal(false);
+    });
+
+    it('should return false when retries is 0', () => {
+      const retryStrategy = new DefaultRetryStrategy({ statusCodes: [503] });
+      mockClientError.response.status = 503;
+
+      const shouldRetry = retryStrategy.shouldRetry(mockClientError, 1, 0);
+      expect(shouldRetry).to.equal(false);
+    });
+
+    it('should return delay using exponential backoff when Retry-After header is not present', () => {
+      const retryStrategy = new DefaultRetryStrategy();
+      const delay = retryStrategy.getDelay(mockClientError, 3);
+      const expectedDelay = Math.pow(retryStrategy['factor'], 3 - 1) * 1000;
+      expect(delay).to.equal(expectedDelay);
+    });
+
+    it('should use custom exponential factor', () => {
+      const customFactor = 3;
+      const retryStrategy = new DefaultRetryStrategy({ statusCodes: [429], factor: customFactor });
+
+      const delay = retryStrategy.getDelay(mockClientError, 3);
+      const expectedDelay = Math.pow(customFactor, 3 - 1) * 1000;
+      expect(delay).to.equal(expectedDelay);
+    });
+  });
 });

packages/sitecore-jss/src/graphql-request-client.ts

@@ -77,12 +77,13 @@ export class DefaultRetryStrategy implements RetryStrategy {
   private factor: number;
 
   /**
-   * @param {number[]} statusCodes HTTP status codes to trigger retries on
-   * @param {number} factor Factor by which the delay increases with each retry attempt
+   * @param {Object} options Configurable options for retry mechanism.
+   * @param {number[]} options.statusCodes HTTP status codes to trigger retries on
+   * @param {number} options.factor Factor by which the delay increases with each retry attempt
    */
-  constructor(statusCodes?: number[], factor?: number) {
-    this.statusCodes = statusCodes || [429];
-    this.factor = factor || 2;
+  constructor(options: { statusCodes?: number[]; factor?: number } = {}) {
+    this.statusCodes = options.statusCodes || [429];
+    this.factor = options.factor || 2;
   }
 
   shouldRetry(error: ClientError, attempt: number, retries: number): boolean {
@@ -98,7 +99,7 @@ export class DefaultRetryStrategy implements RetryStrategy {
     const rawHeaders = error.response?.headers;
     const delaySeconds = rawHeaders?.get('Retry-After')
       ? Number.parseInt(rawHeaders?.get('Retry-After'), 10)
-      : Math.pow(this.factor, attempt);
+      : Math.pow(this.factor, attempt - 1);
 
     return delaySeconds * 1000;
   }
@@ -136,7 +137,7 @@ export class GraphQLRequestClient implements GraphQLClient {
     this.retries = clientConfig.retries || 0;
     this.retryStrategy =
       clientConfig.retryStrategy ||
-      new DefaultRetryStrategy([429, 502, 503, 504, 520, 521, 522, 523, 524]);
+      new DefaultRetryStrategy({ statusCodes: [429, 502, 503, 504, 520, 521, 522, 523, 524] });
     this.client = new Client(endpoint, {
       headers: this.headers,
       fetch: clientConfig.fetch,