From 15337b5bdf0b71488c43df6670a4e61b72c15447 Mon Sep 17 00:00:00 2001
From: Tom Moor <tom.moor@gmail.com>
Date: Tue, 20 Oct 2020 07:41:17 -0700
Subject: [PATCH] fix: Improve error handling when redis connection is lost

---
 server/main.js  |  9 +++++++++
 server/redis.js | 12 ++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/server/main.js b/server/main.js
index 840625e8..cf8cc188 100644
--- a/server/main.js
+++ b/server/main.js
@@ -27,6 +27,15 @@ io.adapter(
   })
 );
 
+io.of("/").adapter.on("error", (err) => {
+  if (err.name === "MaxRetriesPerRequestError") {
+    console.error(`Redis error: ${err.message}. Shutting down now.`);
+    throw err;
+  } else {
+    console.error(`Redis error: ${err.message}`);
+  }
+});
+
 SocketAuth(io, {
   authenticate: async (socket, data, callback) => {
     const { token } = data;
diff --git a/server/redis.js b/server/redis.js
index 2b58feb0..55d614e7 100644
--- a/server/redis.js
+++ b/server/redis.js
@@ -1,8 +1,16 @@
 // @flow
 import Redis from "ioredis";
 
-const client = new Redis(process.env.REDIS_URL);
-const subscriber = new Redis(process.env.REDIS_URL);
+const options = {
+  maxRetriesPerRequest: 20,
+  retryStrategy(times) {
+    console.warn(`Retrying redis connection: attempt ${times}`);
+    return Math.min(times * 100, 3000);
+  },
+};
+
+const client = new Redis(process.env.REDIS_URL, options);
+const subscriber = new Redis(process.env.REDIS_URL, options);
 
 // More than the default of 10 listeners is expected for the amount of queues
 // we're running. Increase the max here to prevent a warning in the console: