Search code examples
javascriptnode.jssocketsherokuredis

Heroku with redis continously logs Informations and also socket error

I use heroku, redis and nodejs with express. After I setup the redis on my node app, I was able to cache data. However, in the Heroku log console, i get continously logs in the following format:

2024-04-21T18:54:09.000000+00:00 app[heroku-redis]: source=REDIS addon=redis-octagonal-55498 sample#active-connections=3 sample#load-avg-1m=3.63 sample#load-avg-5m=3.3 sample#load-avg-15m=3.96 sample#read-iops=0 sample#write-iops=0 sample#memory-total=16070704kB sample#memory-free=8981520kB sample#memory-cached=3846880kB sample#memory-redis=553608bytes sample#hit-rate=0.86207 sample#evicted-keys=0

It doesn't look like an infinite loop, it is logging these info from 1 minute to another. But between, I get the following:

2024-04-21T18:55:20.062782+00:00 app[web.1]: Error connecting to Redis: SocketClosedUnexpectedlyError: Socket closed unexpectedly
2024-04-21T18:55:20.062819+00:00 app[web.1]:     at TLSSocket.<anonymous> (/app/node_modules/@redis/client/dist/lib/client/socket.js:194:118)
2024-04-21T18:55:20.062820+00:00 app[web.1]:     at Object.onceWrapper (node:events:633:26)
2024-04-21T18:55:20.062820+00:00 app[web.1]:     at TLSSocket.emit (node:events:530:35)
2024-04-21T18:55:20.062821+00:00 app[web.1]:     at node:net:337:12
2024-04-21T18:55:20.062821+00:00 app[web.1]:     at TCP.done (node:_tls_wrap:657:7)
2024-04-21T18:55:20.071389+00:00 app[web.1]: Connected to Redis

The error allows redis to reconnect. I am able to continue using my cache.

I need to mention that this is my first time I use redis, especially in production. The initiation of the redis library is created straight into my express project app.js file.

import redis from 'redis';
const REDIS_URL = process.env.REDIS_TLS_URL || process.env.REDIS_URL;

export const redisClient = redis.createClient({
    url: REDIS_URL,
    socket: {
      tls: true,
      rejectUnauthorized: false
    }
});
redisClient.connect();
redisClient.on('connect',   () => console.log('Connected to Redis'));
redisClient.on('error',     error => console.error('Error connecting to Redis:', error));

Regarding the use , I use the redisClient in controllers. For example

        const cachedTargetMuscles  = await redisClient.get('targetMuscles');

Can you please help me find what is wrong? Many thanks, Daniel

Solution

  • I'd say it is safe to ignore the SocketClosedUnexpectedlyError errors as long as the app processes are able to quickly reconnect. By default, Heroku Data for Redis are configured to disconnect after 5 minutes of inactivity.