Feature: Implement retries mechanism

package.json

@@ -26,11 +26,13 @@
   "dependencies": {
     "axios": "^1.6.2",
     "http-cookie-agent": "^5.0.4",
+    "retry": "^0.13.1",
     "tough-cookie": "^4.1.3"
   },
   "devDependencies": {
     "@types/jest": "^29.5.11",
     "@types/node": "^14.14.31",
+    "@types/retry": "^0.12.5",
     "@types/tough-cookie": "^4.0.5",
     "@typescript-eslint/eslint-plugin": "^6.18.1",
     "@typescript-eslint/parser": "^6.18.1",

src/client.test.ts

@@ -49,6 +49,7 @@ describe('Client', () => {
         url: 'https://api.swell.store',
         verifyCert: true,
         version: 1,
+        retries: 0,
       });
     });
 
@@ -63,6 +64,7 @@ describe('Client', () => {
         url: 'https://api.swell.store',
         verifyCert: false,
         version: 2,
+        retries: 0,
       });
     });
 
@@ -141,11 +143,7 @@ describe('Client', () => {
 
       mock.onPost('/products').reply(200, 'result');
 
-      const response = await client.request(
-        HttpMethod.post,
-        '/products',
-        {},
-      );
+      const response = await client.request(HttpMethod.post, '/products', {});
 
       expect(response).toEqual('result');
     });
@@ -155,11 +153,9 @@ describe('Client', () => {
 
       mock.onPut('/products/{id}').reply(200, 'result');
 
-      const response = await client.request(
-        HttpMethod.put,
-        '/products/{id}',
-        { id: 'foo' },
-      );
+      const response = await client.request(HttpMethod.put, '/products/{id}', {
+        id: 'foo',
+      });
 
       expect(response).toEqual('result');
     });
@@ -198,4 +194,63 @@ describe('Client', () => {
       ).rejects.toThrow(new Error('timeout of 0ms exceeded'));
     });
   }); // describe: #request
+
+  describe('#retry', () => {
+    test('handle zero retries by default', async () => {
+      const client = new Client('id', 'key');
+
+      // Simulate server failure on first 2 attempts and success on the third
+      let retryCounter = 0;
+      mock.onGet('/products/:count').reply(() => {
+        retryCounter++;
+        if (retryCounter < 2) {
+          throw new Error('Internal Server Error');
+        }
+        return [200, 42];
+      });
+
+      await expect(
+        client.request(HttpMethod.get, '/products/:count', {}),
+      ).rejects.toThrow(new Error('Internal Server Error'));
+    });
+
+    test('handle retries option', async () => {
+      const client = new Client('id', 'key', { retries: 3 });
+
+      // Simulate server failure on first 2 attempts and success on the third
+      let retryCounter = 0;
+      mock.onGet('/products/:count').reply(() => {
+        retryCounter++;
+        if (retryCounter < 2) {
+          throw new Error('Internal Server Error');
+        }
+        return [200, 42];
+      });
+
+      const response = await client.request(
+        HttpMethod.get,
+        '/products/:count',
+        {},
+      );
+      expect(response).toEqual(42);
+    });
+
+    test('handle return error if response not received after retries', async () => {
+      const client = new Client('id', 'key', { retries: 3 });
+
+      // Simulate server failure on first 4 attempts and success on the fifth
+      let retryCounter = 0;
+      mock.onGet('/products/:count').reply(() => {
+        retryCounter++;
+        if (retryCounter < 5) {
+          throw new Error('Internal Server Error');
+        }
+        return [200, 42];
+      });
+
+      await expect(
+        client.request(HttpMethod.get, '/products/:count', {}),
+      ).rejects.toThrow(new Error('Internal Server Error'));
+    });
+  }); // describe: #retry
 });

src/client.ts

@@ -1,4 +1,5 @@
 import * as axios from 'axios';
+import * as retry from 'retry';
 import { CookieJar } from 'tough-cookie';
 import { HttpCookieAgent, HttpsCookieAgent } from 'http-cookie-agent/http';
 
@@ -19,6 +20,7 @@ export interface ClientOptions {
   version?: number;
   timeout?: number;
   headers?: HttpHeaders;
+  retries?: number;
 }
 
 const MODULE_VERSION: string = (({ name, version }) => {
@@ -35,6 +37,7 @@ const DEFAULT_OPTIONS: Readonly<ClientOptions> = Object.freeze({
   verifyCert: true,
   version: 1,
   headers: {},
+  retries: 0, // 0 => no retries
 });
 
 class ApiError extends Error {
@@ -163,21 +166,36 @@ export class Client {
     url: string,
     data?: unknown,
   ): Promise<T> {
-    if (this.httpClient === null) {
-      throw new Error('Swell API client not initialized');
-    }
-
     // Prepare url and data for request
     const requestParams = transformRequest(method, url, data);
 
-    let response;
-    try {
-      response = await this.httpClient.request<T>(requestParams);
-    } catch (error) {
-      throw transformError(error);
-    }
-
-    return transformResponse(response).data;
+    return new Promise((resolve, reject) => {
+      const { retries } = this.options;
+
+      const operation = retry.operation({
+        retries,
+        minTimeout: 20,
+        maxTimeout: 100,
+        factor: 1,
+        randomize: false,
+      });
+
+      operation.attempt(async () => {
+        if (this.httpClient === null) {
+          return reject(new Error('Swell API client not initialized'));
+        }
+
+        try {
+          const response = await this.httpClient.request<T>(requestParams);
+          resolve(transformResponse(response).data);
+        } catch (error) {
+          if (operation.retry(error as Error)) {
+            return;
+          }
+          reject(transformError(operation.mainError()));
+        }
+      });
+    });
   }
 }