@nimpl/cache-redis

@nimpl/cache-redis

Redis-based cache handler with multi-pod support. Designed for Next.js but can be used to build custom caching solutions for any other stack (e.g. cache function in React Router 7 or Remix).

Overview

@nimpl/cache-redis is a showcase library that demonstrates how to build a cache handler using @nimpl/cache. It implements a two-tier caching strategy: an in-memory LRU cache for fast local access and Redis for shared cache across multiple pods.

Note: This is a showcase library. In most cases, you should build your own cache-handler using @nimpl/cache to have full control over configuration and layers.

For detailed information on handlers, layers, custom implementations, and advanced configuration, see the @nimpl/cache README.

How It Works

The cache handler uses a layered approach:

• In-Memory Layer: LRU cache stores frequently accessed entries locally for sub-millisecond retrieval
• Redis Layer: Persistent cache shared across all pods, ensuring cache consistency in distributed deployments
• Pending Operations: Deduplicates concurrent read and write requests for the same key to prevent cache stampede

On cache miss in-memory, the handler fetches from Redis and populates the local LRU cache.

Installation

npm install @nimpl/cache-redis
# or
pnpm add @nimpl/cache-redis

Configuration

Next.js Setup

Configure the cache handler in next.config.ts:

import { type NextConfig } from "next/types";

const nextConfig: NextConfig = {
  cacheComponents: true,
  cacheHandlers: {
    default: import.meta.resolve("@nimpl/cache-redis"),
  },
};

export default nextConfig;

Options

The cache handler accepts the following parameters (all optional):

• logger (Logger): Custom logging function. Default: console logger (enabled when NEXT_PRIVATE_DEBUG_CACHE or NIC_LOGGER is set)
• lruOptions (LRUCache.Options): Options for the LRU cache instance
  • maxSize: Maximum cache size in bytes. Default: 50 * 1024 * 1024 (50MB) or LRU_CACHE_MAX_SIZE env var (in MB)
  • ttl (number | "auto"): Time-to-live in seconds. Default: "auto"
• redisOptions (RedisOptions): Redis connection options from ioredis
  • url: Redis connection URL. Default: process.env.REDIS_URL || "redis://localhost:6379"
  • connectionStrategy ("ignore" | "wait-ignore" | "wait-throw" | "wait-exit"): Connection failure behavior. Default: "ignore"

Custom Configuration

You can initialize the cache handler with custom configuration:

// cache-handlers/redis.js
import { CacheHandler } from "@nimpl/cache-redis/cache-handler";

global.cacheHandler ||= new CacheHandler({
  lruOptions: { maxSize: 100 * 1024 * 1024 },
  redisOptions: { connectionStrategy: "wait-ignore" },
});

// next.config.ts
import { type NextConfig } from "next/types";

const nextConfig: NextConfig = {
  cacheComponents: true,
  cacheHandlers: {
    default: import.meta.resolve("./cache-handlers/redis.js"),
  },
};

export default nextConfig;

Note: It is recommended to write to global, as otherwise the instance will be created differently for Next.js and for your independent use (for example, for cache-widget or your internal utilities). As a result, in-memory entries will be different, and will also be duplicated.

Usage

Next.js

Use Next.js cache APIs as usual:

import { cacheLife } from "next/cache";

export default async function Page() {
  "use cache";
  cacheLife({ stale: 30, revalidate: 60, expire: 120 });

  // Your component logic
}

Other Frameworks

The cache handler can be used directly with @nimpl/cache-tools:

import { CacheHandler } from "@nimpl/cache-redis/cache-handler";
import { createCache } from "@nimpl/cache-tools";

const cacheHandler = new CacheHandler({
  redisOptions: { keyPrefix: "admin:" },
});

export const { cache } = createCache(cacheHandler);

Additional Information

For detailed information on:

• Custom handlers and layers implementation
• Method specifications and requirements
• Health checks and readiness probes
• Multi-pod support details
• Serverless environment considerations
• Limitations and best practices

See the @nimpl/cache README.

Examples

• Base Example - Minimal Next.js example demonstrating filesystem cache handler and cache widget
• React Router Example - Source code
• Next.js cacheComponents Example - Source code

License

MIT