RedisJSON Memory Server

Forked from redis-memory-server with added RedisJSON module support.

This package spins up a real Redis server programmatically from Node.js, for testing or mocking during development — with optional RedisJSON module support for native JSON data type commands (JSON.SET, JSON.GET, etc.).

It holds the data in memory. Each redis-server process takes about 4Mb of memory. The server will allow you to connect your favorite client library to the Redis server and run integration tests isolated from each other.

On install, it downloads the Redis source, compiles the redis-server binary, and saves it to a cache folder.

On starting a new instance of the in-memory server, if the binary cannot be found, it will be downloaded and compiled; thus, the first run may take some time. All further runs will be fast because they will use the downloaded binaries. NOTE: If no version is specified (or version is set to stable), the binary will not be updated after the first run.

This package automatically downloads source code from https://download.redis.io/.

Every RedisMemoryServer instance starts a fresh Redis server on a free port. You may start up several redis-server processes simultaneously. When you terminate your script or call stop(), the Redis server(s) will be automatically shut down.

It works in Travis CI without additional services or addons in .travis.yml.

• Redis In-Memory Server
  • Installation
    • Requirements
    • Windows
    • Configuring which redis-server binary to use
      • Using the stable version of the binary
  • Usage
    • Simple server start
    • Start server via npx
    • Available options for RedisMemoryServer
    • Options which can be set via environment variables
    • Options which can be set via package.json
    • Simple test with ioredis
    • Debug mode
  • RedisJSON Module Support
    • How It Works
    • Quickstart — enableJSON shorthand
    • Using a pre-built module binary
    • Module Configuration Reference
  • Credits
  • License

Installation

yarn add redis-memory-server --dev
# OR
npm install redis-memory-server --save-dev

On install, this package auto-downloads and compiles version stable of the redis-server binary to node_modules/.cache/redis-memory-server/redis-binaries.

Requirements

• make

Windows

This library uses the latest version of Memurai on Windows. Currently, it is not possible to specify a particular version of Memurai or Redis on Windows.

Configuring which redis-server binary to use

The default behavior is that version stable will be downloaded. You can set configurations via environment variables or via package.json.

Using the stable version of the binary

After the first install of the stable version on a machine, the binary will not be automatically updated on that machine.

This may be a concern because:

1. the install is less deterministic
2. some machines could have vulnerable versions

If this is a concern, either:

1. specify a version other than stable
2. forcibly update the stable binary on demand using a command like:

REDISMS_IGNORE_DOWNLOAD_CACHE=true yarn rebuild redis-memory-server
# OR
REDISMS_IGNORE_DOWNLOAD_CACHE=true npm rebuild redis-memory-server

3. specify the ignoreDownloadCache option (NOTE: this will make installs/runs slower)

Usage

Simple server start

import { RedisMemoryServer } from 'redis-memory-server';

const redisServer = new RedisMemoryServer();

const host = await redisServer.getHost();
const port = await redisServer.getPort();

// `redis-server` has been started
// you may use `host` and `port` as connection parameters for `ioredis` (or similar)

// you may check instance status
redisServer.getInstanceInfo(); // returns an object with instance data

// you may stop `redis-server` manually
await redisServer.stop();

// when `redis-server` is killed, its running status should be `false`
redisServer.getInstanceInfo();

// even if you forget to stop `redis-server`,
// when your script exits, a special process killer will shut it down for you

Start server via npx

npx redis-memory-server
# OR
REDISMS_PORT=6379 npx redis-memory-server

Available options for RedisMemoryServer

All settings are optional.

const redisServer = new RedisMemoryServer({
  instance: {
    port: number, // by default, choose any free port
    ip: string, // by default, '127.0.0.1'; for binding to all IP addresses set it to `::,0.0.0.0`,
    args: [], // by default, no additional arguments; any additional command line arguments for `redis-server`
  },
  binary: {
    version: string, // by default, 'stable'
    downloadDir: string, // by default, 'node_modules/.cache/redis-memory-server/redis-binaries'
    ignoreDownloadCache: boolean, // by default, false
    systemBinary: string, // by default, undefined
  },
  autoStart: boolean, // by default, true
});

Options which can be set via environment variables

REDISMS_DOWNLOAD_DIR=/path/to/redis/binaries # default target download directory
REDISMS_VERSION=6.0.10 # default version to download
REDISMS_IGNORE_DOWNLOAD_CACHE=true
REDISMS_DEBUG=true
REDISMS_DOWNLOAD_MIRROR=host # your mirror host to download the redis binary
REDISMS_DOWNLOAD_URL=url # full URL to download the redis binary
REDISMS_DISABLE_POSTINSTALL=true
REDISMS_SYSTEM_BINARY=/usr/local/bin/redis-server # if you want to use an existing binary already on your system.

NOTE: Boolean-ish values can be any of these (case-insensitive): true, on, yes, 1.

Options which can be set via package.json

You can also use package.json to configure the installation process. It will search up the hierarchy looking for package.json files and combine all configurations, where closer package.json files take precedence. Environment variables have higher priority than contents of package.json files.

{
  "redisMemoryServer": {
    "downloadDir": "/path/to/redis/binaries",
    "version": "6.0.10",
    "ignoreDownloadCache": true,
    "debug": true,
    "downloadMirror": "url",
    "disablePostinstall": true,
    "systemBinary": "/usr/local/bin/redis-server",
    "configProvider": "some-package/redisMemoryServerConfig.js"
  }
}

NOTE: Boolean-ish values can be any of these (case-insensitive): true, "true", "on", "yes", 1, "1".

By default, it starts looking for package.json files at process.cwd(). To change this:

import { findPackageJson } from 'redis-memory-server/lib/util/resolve-config';

findPackageJson('/custom/path');

The configProvider configuration can be used to dynamically load configurations from another package (e.g. some-package/redisMemoryServerConfig.js) or file (e.g. ./redisMemoryServerConfig.js), where the target file looks like this:

module.exports = {
  version: '6.0.10',
  // ...
}

Simple test with ioredis

Take a look at this test file.

Debug mode

Debug mode can be enabled with an environment variable or in package.json:

REDISMS_DEBUG=true

or

{
  "redisMemoryServer": {
    "debug": true
  }
}

RedisJSON Module Support

This package supports loading the RedisJSON module, enabling native JSON data type support (JSON.SET, JSON.GET, etc.) for testing with Redis Stack-like capabilities.

How It Works

RedisJSON is a Redis module that adds native JSON data type support. This implementation:

1. Resolves the module binary — via a pre-built system path, cache, or by downloading and building from source
2. Passes --loadmodule /path/to/librejson.so to the redis-server process at startup
3. Detects module load errors in stdout and surfaces them clearly

Redis 8+ Note: Starting with Redis 8, JSON commands are built into Redis natively. If you're using Redis 8+, you don't need this module system at all — just use redis-memory-server normally and JSON commands will be available.

Quickstart — enableJSON shorthand

import RedisMemoryServer from 'redis-memory-server';

const server = new RedisMemoryServer({
  modules: {
    enableJSON: true,
  },
});

const host = await server.getHost();
const port = await server.getPort();

// Now use any Redis client with JSON commands:
// JSON.SET, JSON.GET, JSON.DEL, etc.

Using a pre-built module binary

If you already have librejson.so on your system (e.g. from a Redis Stack installation), point to it directly — no download or build step required:

const server = new RedisMemoryServer({
  modules: {
    modules: [
      {
        name: 'rejson',
        systemModule: '/opt/redis-stack/lib/rejson.so',
      },
    ],
  },
});

Or via environment variable:

REDISMS_MODULE_REJSON_SYSTEM_BINARY=/opt/redis-stack/lib/rejson.so

You can also specify a version or pass module arguments:

const server = new RedisMemoryServer({
  modules: {
    modules: [
      {
        name: 'rejson',
        version: '2.6.0', // downloads this specific tag from GitHub
        args: ['SOME_CONFIG', 'value'], // extra args after --loadmodule <path>
      },
    ],
  },
});

Module Configuration Reference

RedisMemoryServerOptsT.modules

| Property | Type | Description | |---|---|---| | enableJSON | boolean | Shorthand to enable RedisJSON with defaults | | modules | RedisModuleOpts[] | Explicit list of modules to load |

RedisModuleOpts

| Property | Type | Default | Description | |---|---|---|---| | name | 'rejson' | (required) | Module identifier | | version | string | 'latest' | Version tag to download from GitHub | | systemModule | string | — | Path to a pre-built .so binary (skips download) | | downloadDir | string | cache dir | Where to store downloaded/built module binaries | | args | string[] | — | Extra args appended after --loadmodule <path> |

Module Environment Variables

| Variable | Description | |---|---| | REDISMS_MODULE_REJSON_SYSTEM_BINARY | Path to a pre-built librejson.so | | REDISMS_MODULE_DOWNLOAD_DIR | Override the default module download/cache directory |

Credits

Forked from redis-memory-server by @mhassan1, which is inspired by mongodb-memory-server.

License

MIT