From 8703da5ad89c1d968a4140b5f1049c92a35fdac9 Mon Sep 17 00:00:00 2001
From: Asa Oines <asaoines@gmail.com>
Date: Mon, 1 Aug 2022 14:08:43 -0400
Subject: [PATCH] Update RetryProvider to use exponential backoff (#859)

---
 typescript/infra/src/config/chain.ts          |  4 +--
 typescript/sdk/src/providers/RetryProvider.ts | 25 +++++++++++++------
 typescript/utils/src/utils.ts                 | 11 ++++----
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/typescript/infra/src/config/chain.ts b/typescript/infra/src/config/chain.ts
index 37c890e8e..688f333e5 100644
--- a/typescript/infra/src/config/chain.ts
+++ b/typescript/infra/src/config/chain.ts
@@ -19,8 +19,8 @@ export async function fetchProvider(
   const provider = celoChainNames.has(chainName)
     ? new StaticCeloJsonRpcProvider(rpc)
     : new RetryJsonRpcProvider(new ethers.providers.JsonRpcProvider(rpc), {
-        retryLimit: 2,
-        interval: 250,
+        maxRequests: 6,
+        baseRetryMs: 50,
       });
   return provider;
 }
diff --git a/typescript/sdk/src/providers/RetryProvider.ts b/typescript/sdk/src/providers/RetryProvider.ts
index 1fd6d6a40..fada2f827 100644
--- a/typescript/sdk/src/providers/RetryProvider.ts
+++ b/typescript/sdk/src/providers/RetryProvider.ts
@@ -2,16 +2,17 @@
 //
 // Mostly taken from the removed version that was in ethers.js
 // See: https://github.com/ethers-io/ethers.js/discussions/3006
+import { assert } from 'console';
 import { ethers } from 'ethers';
 
 import { utils } from '@abacus-network/utils';
 
 export type RetryOptions = {
-  // The wait interval in between
-  interval: number;
+  // Maximum number of times to make the RPC
+  maxRequests: number;
 
-  // Maximum number of times to retry
-  retryLimit: number;
+  // Exponential backoff base value
+  baseRetryMs: number;
 };
 
 export class RetryProvider extends ethers.providers.BaseProvider {
@@ -20,6 +21,10 @@ export class RetryProvider extends ethers.providers.BaseProvider {
     readonly retryOptions: RetryOptions,
   ) {
     super(provider.getNetwork());
+    assert(
+      retryOptions.maxRequests >= 1,
+      'RetryOptions.maxRequests must be >= 1',
+    );
     ethers.utils.defineReadOnly(this, 'provider', provider);
     ethers.utils.defineReadOnly(this, 'retryOptions', retryOptions);
   }
@@ -28,8 +33,8 @@ export class RetryProvider extends ethers.providers.BaseProvider {
   perform(method: string, params: any): Promise<any> {
     return utils.retryAsync(
       () => this.provider.perform(method, params),
-      this.retryOptions.retryLimit,
-      this.retryOptions.interval,
+      this.retryOptions.maxRequests,
+      this.retryOptions.baseRetryMs,
     );
   }
 }
@@ -41,13 +46,17 @@ export class RetryJsonRpcProvider extends ethers.providers.JsonRpcProvider {
     readonly retryOptions: RetryOptions,
   ) {
     super(provider.connection, provider.network);
+    assert(
+      retryOptions.maxRequests >= 1,
+      'RetryOptions.maxRequests must be >= 1',
+    );
   }
 
   async send(method: string, params: Array<any>): Promise<any> {
     return utils.retryAsync(
       async () => this.provider.send(method, params),
-      this.retryOptions.retryLimit,
-      this.retryOptions.interval,
+      this.retryOptions.maxRequests,
+      this.retryOptions.baseRetryMs,
     );
   }
 }
diff --git a/typescript/utils/src/utils.ts b/typescript/utils/src/utils.ts
index 4201b9fb2..70a9a7e24 100644
--- a/typescript/utils/src/utils.ts
+++ b/typescript/utils/src/utils.ts
@@ -101,12 +101,13 @@ export function sleep(ms: number): Promise<void> {
   return new Promise<void>((resolve) => setTimeout(resolve, ms));
 }
 
-// Retries an async function when it raises an exception
-// if all the tries fail it raises the last thrown exception
+// Retries an async function if it raises an exception,
+// with exponential backoff.
+// If all the tries fail it raises the last thrown exception
 export async function retryAsync<T>(
   runner: () => T,
-  attempts = 3,
-  delay = 500,
+  attempts = 5,
+  baseRetryMs = 50,
 ) {
   let saveError;
   for (let i = 0; i < attempts; i++) {
@@ -114,7 +115,7 @@ export async function retryAsync<T>(
       return runner();
     } catch (error) {
       saveError = error;
-      await sleep(delay * (i + 1));
+      await sleep(baseRetryMs * 2 ** i);
     }
   }
   throw saveError;