feat(node): exponential retry of requests on failure

src/Node.ts

@@ -3,7 +3,7 @@ import BigNumber from 'bignumber.js';
 import { OperationArguments, OperationSpec } from '@azure/core-client';
 import {
   genRequestQueuesPolicy, genCombineGetRequestsPolicy, genErrorFormatterPolicy,
-  genVersionCheckPolicy,
+  genVersionCheckPolicy, genRetryOnFailurePolicy,
 } from './utils/autorest';
 import { Node as NodeApi, NodeOptionalParams, ErrorModel } from './apis/node';
 import { mapObject } from './utils/other';
@@ -128,6 +128,7 @@ export default class Node extends (NodeTransformed as unknown as NodeTransformed
       additionalPolicies: [
         genRequestQueuesPolicy(),
         genCombineGetRequestsPolicy(),
+        genRetryOnFailurePolicy(),
         genErrorFormatterPolicy((body: ErrorModel) => ` ${body.reason}`),
       ],
       ...options,

src/utils/autorest.ts

@@ -2,7 +2,7 @@ import { RestError, PipelineResponse, PipelinePolicy } from '@azure/core-rest-pi
 import { AdditionalPolicyConfig } from '@azure/core-client';
 import { pause } from './other';
 import semverSatisfies from './semver-satisfies';
-import { UnsupportedVersionError } from './errors';
+import { UnexpectedTsError, UnsupportedVersionError } from './errors';
 
 export const genRequestQueuesPolicy = (): AdditionalPolicyConfig => {
   const requestQueues = new Map<string, Promise<unknown>>();
@@ -106,3 +106,30 @@ export const genVersionCheckPolicy = (
     return next(request);
   },
 });
+
+export const genRetryOnFailurePolicy = (): AdditionalPolicyConfig => ({
+  policy: {
+    name: 'retry-on-failure',
+    async sendRequest(request, next) {
+      const statusesToNotRetry = [200, 400, 403];
+      let error: Error | undefined;
+      for (let attempt = 0; attempt <= 3; attempt += 1) {
+        if (error != null) {
+          if (
+            !(error instanceof RestError)
+            || statusesToNotRetry.includes(error.response?.status ?? 0)
+          ) throw error;
+          await pause((attempt / 3) ** 2 * 500);
+        }
+        try {
+          return await next(request);
+        } catch (e) {
+          error = e;
+        }
+      }
+      if (error == null) throw new UnexpectedTsError();
+      throw error;
+    },
+  },
+  position: 'perCall',
+});

test/integration/node.ts

@@ -17,6 +17,8 @@
 
 import { describe, it, before } from 'mocha';
 import { expect } from 'chai';
+import { spy } from 'sinon';
+import http from 'http';
 import { url, ignoreVersion } from '.';
 import { AeSdkBase, Node, NodeNotFoundError } from '../../src';
 
@@ -43,6 +45,17 @@ describe('Node client', () => {
       .to.be.rejectedWith('v3/transactions/th_test error: Invalid hash');
   });
 
+  it('retries requests if failed', async () => ([
+    ['ak_test', 1],
+    ['ak_2CxRaRcMUGn9s5UwN36UhdrtZVFUbgG1BSX5tUAyQbCNneUwti', 4],
+  ] as const).reduce(async (prev, [address, requestCount]) => {
+    await prev;
+    const httpSpy = spy(http, 'request');
+    await node.getAccountByPubkey(address).catch(() => {});
+    expect(httpSpy.callCount).to.be.equal(requestCount);
+    httpSpy.restore();
+  }, Promise.resolve()));
+
   describe('Node Pool', () => {
     it('Throw error on using API without node', () => {
       const nodes = new AeSdkBase({});