Problem with running SCAN on ElastiCache Redis

[justinasit]

Hello!

Issue

I'm having problems getting the SCAN command to run through node-redis on an ElastiCache Redis cluster. Here's a simple block of code that outputs all keys in the cache:

const redisClient = redis.createClient(process.env.CACHE_PORT, process.env.CACHE_HOST, {
    retry_strategy: (options) => {
      if (options.attempt > 10) {
        return;
      }
    },
  });
  redisClient.scan(0, (error, result) => {
    console.log(error);
    console.log(result);
  });

It works perfectly on my local machine, but on a lambda function that connects to ElastiCache - it does not produce any output. The function continues fine (it doesn't hang), but I can't see neither an error, nor a result.

I have no issues using node-redis to run GET and SET commands.

I also tried logging onto the ElastiCache cluster using redis-cli. I executed scan 0 there (no arguments) and got the results back successfully.

The problem was first reported on issue #1314 (at the bottom) on 14 Jan 2020, so I assume this is not a recent problem.

Any help is appreciated. Thanks!

---

Environment

• Node.js Version: Node.Js 12

• Redis Version: 6.0.5 (ElastiCache), 6.0.9 (Locally)

• node-redis Version: 3.1.2

• Platform: AWS Lambda, Mac OS X (Locally)