Clients

The cache only needs eval, so it works with any Valkey or Redis client. Each of these is tested against Valkey.

ioredis and iovalkey (the Valkey community's fork of ioredis) fit as they are, Redis and Cluster alike:

import { Redis } from 'iovalkey'; // or 'ioredis'
import { LeaseCache } from 'lease-cache';

const cache = new LeaseCache({
    connection: new Redis('redis://valkey:6379'),
    prefix: 'users',
    ttlMs: 60_000,
    leaseMs: 5000,
    pollMs: 50,
    waitMs: 2000,
});

node-redis (redis) takes keys and arguments in an options object:

import type { LeaseCacheConnection } from 'lease-cache';
import { createClient } from 'redis';

const client = await createClient({ url: 'redis://valkey:6379' }).connect();
const connection: LeaseCacheConnection = {
    eval: async (script, numKeys, ...args) => {
        const strings = args.map(String);
        return client.eval(script, {
            keys: strings.slice(0, numKeys),
            arguments: strings.slice(numKeys),
        });
    },
};

Valkey GLIDE (@valkey/valkey-glide) runs scripts through Script objects, which it loads once and then runs by hash (EVALSHA). Keep one per script, since each must be released:

import { GlideClient, Script } from '@valkey/valkey-glide';
import type { LeaseCacheConnection } from 'lease-cache';

const client = await GlideClient.createClient({ addresses: [{ host: 'valkey', port: 6379 }] });
// lease-cache uses a handful of fixed scripts, so these live as long as the client
const scripts = new Map<string, Script>();
const connection: LeaseCacheConnection = {
    eval: async (code, numKeys, ...args) => {
        let script = scripts.get(code);
        if (!script) {
            script = new Script(code);
            scripts.set(code, script);
        }
        const strings = args.map(String);
        return client.invokeScript(script, {
            keys: strings.slice(0, numKeys),
            args: strings.slice(numKeys),
        });
    },
};

On a cluster, use the client's cluster mode (ioredis's Cluster, node-redis's createCluster, GlideClusterClient): each key's value, lease and stale value share a hash tag, so they live on the same node. For the tag to work, a key can't be empty or start with } (LeaseCacheKeyError), and the prefix can't contain { (LeaseCachePrefixError). The tests only cover a single server.