From e9b3e57abce8108a414c0f0c0fae8adc1c7c604f Mon Sep 17 00:00:00 2001
From: ohad-israeli <ohadisra@gmail.com>
Date: Mon, 7 Dec 2020 20:31:23 +0200
Subject: [PATCH] feat(cluster): support retrying MOVED with a delay

Add delay to MOVED response. In case a MOVED response is recieved from the cluster use a delayed queue to retry commands
---
 lib/cluster/ClusterOptions.ts |  8 ++++++++
 lib/cluster/index.ts          | 10 +++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/cluster/ClusterOptions.ts b/lib/cluster/ClusterOptions.ts
index 6b76b2bc0..9565c1526 100644
--- a/lib/cluster/ClusterOptions.ts
+++ b/lib/cluster/ClusterOptions.ts
@@ -38,6 +38,13 @@ export interface IClusterOptions {
     reason?: Error
   ) => number | void | null;
 
+  /**
+   * See "Quick Start" section.
+   *
+   * @default (times) => Math.min(50 + times * 2, 2000)
+   */
+  retryDelayOnMoved?: (times: number, reason?: Error) => number | null;
+
   /**
    * See Redis class.
    *
@@ -180,6 +187,7 @@ export interface IClusterOptions {
 
 export const DEFAULT_CLUSTER_OPTIONS: IClusterOptions = {
   clusterRetryStrategy: (times) => Math.min(100 + times * 2, 2000),
+  retryDelayOnMoved: (times) => Math.min(50 + times * 2, 2000),
   enableOfflineQueue: true,
   enableReadyCheck: true,
   scaleReads: "master",
diff --git a/lib/cluster/index.ts b/lib/cluster/index.ts
index 06bdd10e7..d8afbc56d 100644
--- a/lib/cluster/index.ts
+++ b/lib/cluster/index.ts
@@ -746,7 +746,15 @@ class Cluster extends EventEmitter {
     }
     const errv = error.message.split(" ");
     if (errv[0] === "MOVED" || errv[0] === "ASK") {
-      handlers[errv[0] === "MOVED" ? "moved" : "ask"](errv[1], errv[2]);
+      this.delayQueue.push(
+        "moved",
+        handlers.moved.bind(null, errv[1], errv[2]),
+        {
+          timeout: this.options.retryDelayOnMoved(
+            this.options.maxRedirections + 1 - ttl.value
+          ),
+        }
+      );
     } else if (errv[0] === "TRYAGAIN") {
       this.delayQueue.push("tryagain", handlers.tryagain, {
         timeout: this.options.retryDelayOnTryAgain,