Migrate from `ioredis` to `node-redis`

[RomainLanz]

The ioredis package has officially moved into maintenance mode, meaning it will only receive security updates and no new features going forward. The Redis team now recommends using node-redis.

[elee1766]

hi. i started working on this for Julien-R44/bentocache#89 (comment)

but i am running into an issue which is that node-redis requires async "connect" methods to be calls.

but transport constructors cannot be async, so this is a problem.

i think there will have to be some breaking changes to the api in order to accommodate the library upgrade as a result - but i dont know what choices you want to make here, and how much you want to break the existing api.

one possible option is maybe to.. just create 'NodeRedisTransport' that has completely different semantics to not break existing ioredis users, so simply add support for node-redis instead of migrating?

[niksy]

Is there any progress on this? I don’t see any opened PRs.

[niksy]

but i am running into an issue which is that node-redis requires async "connect" methods to be calls.

Can this be solved by running connect on each Redis client and checking for opened connections?

Something like this:

const connectionPromises = new WeakMap();
const initializedClients = new WeakSet();

function initializeClient(client) {
  if (initializedClients.has(client)) {
    return;
  }
  client.on('error', () => {});
  initializedClients.add(client);
}

async function ensureConnected(client) {
  if (client.isOpen) {
    return;
  }
  let connectionPromise = connectionPromises.get(client)
  if (!connectionPromise) {
    connectionPromise = client
      .connect()
      .finally(() => connectionPromises.delete(client));
    connectionPromises.set(client, connectionPromise);
  }
  await connectionPromise;
}

In constructor:

import {createClient} from 'redis';
// …
this.#publisher = createClient(config.connection);
initializeClient(this.#publisher);

And then use ensureConnected in every place you need to deal with publisher/subscriber, eg.:

async disconnect() {
  await Promise.all([ensureConnected(this.#publisher), ensureConnected(this.#subscriber)]);
  await Promise.all([this.#publisher.quit(), this.#subscriber.quit()])
}