From cef3ccd72504539ff3f2303889247a6fb2c81210 Mon Sep 17 00:00:00 2001
From: Evgeny <fruneen@gmail.com>
Date: Wed, 13 Dec 2023 19:17:10 +0300
Subject: [PATCH] feat: add improvements for handling redis errors

---
 template/apps/api/src/app.ts                     | 16 ++++++++++++----
 template/apps/api/src/io-emitter.ts              | 16 +++++++---------
 template/apps/api/src/redis-client.ts            | 12 +++++++-----
 .../api/src/services/socket/socket.service.ts    |  4 +++-
 4 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/template/apps/api/src/app.ts b/template/apps/api/src/app.ts
index 840b4cc1..13dab95c 100644
--- a/template/apps/api/src/app.ts
+++ b/template/apps/api/src/app.ts
@@ -21,6 +21,8 @@ import { socketService } from 'services';
 import config from 'config';
 import logger from 'logger';
 import routes from 'routes';
+
+import { redisErrorHandler } from 'redis-client';
 import ioEmitter from 'io-emitter';
 
 const initKoa = () => {
@@ -49,10 +51,16 @@ const app = initKoa();
 (async () => {
   const server = http.createServer(app.callback());
 
-  await Promise.all([
-    ioEmitter.initClient(),
-    socketService(server),
-  ]);
+  if (config.REDIS_URI) {
+    try {
+      await Promise.all([
+        ioEmitter.initClient(),
+        socketService(server),
+      ]);
+    } catch (e) {
+      if (e instanceof Error) redisErrorHandler(e);
+    }
+  }
 
   server.listen(config.PORT, () => {
     logger.info(`API server is listening on ${config.PORT}, in ${config.APP_ENV} environment`);
diff --git a/template/apps/api/src/io-emitter.ts b/template/apps/api/src/io-emitter.ts
index 9a97c245..e926e7b7 100644
--- a/template/apps/api/src/io-emitter.ts
+++ b/template/apps/api/src/io-emitter.ts
@@ -1,20 +1,15 @@
 import { Emitter } from '@socket.io/redis-emitter';
 
-import redisClient from 'redis-client';
+import redisClient, { redisErrorHandler } from 'redis-client';
 import logger from 'logger';
 
-import config from './config';
-
 let emitter: Emitter | null = null;
 
 const publish = (roomId: string | string[], eventName: string, data: unknown) => {
   if (emitter === null) {
-    if (config.REDIS_ERRORS_POLICY === 'throw') {
-      throw new Error('ioEmitter is not initialized.');
-    } else {
-      logger.debug('ioEmitter is not initialized.');
-      return;
-    }
+    redisErrorHandler(new Error('ioEmitter is not initialized.'));
+
+    return;
   }
 
   logger.debug(`published io event [${eventName}] to ${roomId}, the data is: ${JSON.stringify(data)}`);
@@ -24,6 +19,9 @@ const publish = (roomId: string | string[], eventName: string, data: unknown) =>
 
 const initClient = async () => {
   const subClient = redisClient.duplicate();
+
+  subClient.on('error', redisErrorHandler);
+
   await subClient.connect();
 
   emitter = new Emitter(subClient);
diff --git a/template/apps/api/src/redis-client.ts b/template/apps/api/src/redis-client.ts
index 16cd74a9..ba62411c 100644
--- a/template/apps/api/src/redis-client.ts
+++ b/template/apps/api/src/redis-client.ts
@@ -10,21 +10,23 @@ const client = createClient({
     connectTimeout: 30_000,
     reconnectStrategy: (retries) => {
       const maxDelay = 5_000;
-      const baseDelay = 50;
+      const baseDelay = 1_000;
 
       return Math.min(baseDelay * Math.pow(2, retries), maxDelay);
     },
   },
 });
 
-client.on('error', err => {
-  const errorMessage = `redisClient => Redis error: ${err.stack || err}`;
+export const redisErrorHandler = (error: Error) => {
+  const errorMessage = `[Redis Client] ${error.stack || error}`;
 
   if (config.REDIS_ERRORS_POLICY === 'throw') {
-    throw Error(errorMessage);
+    throw new Error(errorMessage);
   } else {
     logger.error(errorMessage);
   }
-});
+};
+
+client.on('error', redisErrorHandler);
 
 export default client;
diff --git a/template/apps/api/src/services/socket/socket.service.ts b/template/apps/api/src/services/socket/socket.service.ts
index 40fff891..d8b09c71 100644
--- a/template/apps/api/src/services/socket/socket.service.ts
+++ b/template/apps/api/src/services/socket/socket.service.ts
@@ -6,7 +6,7 @@ import { COOKIES } from 'app-constants';
 
 import { tokenService } from 'resources/token';
 
-import pubClient from 'redis-client';
+import pubClient, { redisErrorHandler } from 'redis-client';
 import logger from 'logger';
 
 import socketHelper from './socket.helper';
@@ -16,6 +16,8 @@ export default async (server: http.Server) => {
 
   const subClient = pubClient.duplicate();
 
+  subClient.on('error', redisErrorHandler);
+
   await Promise.all([pubClient.connect(), subClient.connect()]);
   logger.info('Socket.io server has been connected.');