balderdashy/sails-redis

sails-redis

Lightweight Redis Adapter for Node.js / Sails Apps

A lightweight Sails/Waterline adapter for Redis. May be used in a Sails app, or any Node.js module using Waterline as its ORM.

Heads up

This adapter does not support the Semantic or Queryable interfaces. Instead, it simply provides robust, managed access to the underlying Redis client. That means you can't use it to call methods like .find(). Instead, use it as a simple way to easily configure, obtain a connection, and communicate with Redis (e.g. for caching) within the lifecycle of your Node.js / Sails application.

Looking for the old repo? See the for-sails-0.12 branch of this repo or ryanc1256/sails-redis for examples of conventional adapters that let you use Redis to directly store and query records from your models.

This is an adapter for Sails versions 1.0 and up. If you are using an earlier version of Sails (or Waterline <v0.13), check out the for-sails-0.12 branch. Since this new release of sails-redis is more lightweight, and does not support the same semantic interface as its predecessor, be aware that there are breaking changes in your app when you upgrade. But I think you'll find that this new release is a great way to easily communicate with Redis, with minimal interference and a stable API. If you are interested in upgrading the new, Sails-v1-compatible release of this Redis adapter to support semantic usage (find, create, update, destroy), then please contact Mike or another core maintainer.

Usage

Install

Install is through NPM.

npm install sails-redis

Getting started

After installing and configuring this adapter (see below), you'll be able to use it to send commands to Redis from your Sails/Node.js app.

Here's an example demonstrating how to look up a cached value from Redis using async/await:

var util = require('util');

// Made up a fake parameter:
var key = 'foo';

// Inspired by https://github.com/node-machine/driver-interface/blob/06776813ff3a29cfa80c0011f3affa07bbc28698/layers/cache/get-cached-value.js
// Redis client docs: https://github.com/NodeRedis/node_redis/tree/v.2.8.0#sending-commands
// See also https://github.com/sailshq/machinepack-redis/blob/f0892e581286eac24757532513387162396356f7/machines/get-cached-value.js#L79-L94
// > If Redis returns `null`, then the value at this key is expired or does
// > not exist.  If a value _was_ found, attempt to JSON.parse() it.
// > (See `set-cached` for more info on why we're deserializing JSON here.)
var value = await sails.getDatastore('cache').leaseConnection(async (db)=>{
  var found = await (util.promisify(db.get).bind(db))(key);
  if (found === null) {
    return undefined;
  } else {
    return JSON.parse(found);
  }
});//¬

And here's another async/await example, this time showing how to set a value in Redis, along with a TTL (i.e. expiry):

var util = require('util');

// Made up some fake parameters:
var key = 'foo';
var value = {
  coolPhrase: `hello world, it's ${new Date()}`,
  iCan: ['put','w/e','I','want',4,'here']
};
var expiresIn = 1000*60*60*24;

// Convert `expiresIn` (which is expressed in milliseconds) to seconds,
// because unlike JavaScript, Redis likes to work with whole entire seconds.
var ttlInSeconds = Math.ceil(expiresIn / 1000);

// Inspired by https://github.com/node-machine/driver-interface/blob/06776813ff3a29cfa80c0011f3affa07bbc28698/layers/cache/cache-value.js
// Redis client docs: https://github.com/NodeRedis/node_redis/tree/v.2.8.0#sending-commands
// See also https://github.com/sailshq/machinepack-redis/blob/f0892e581286eac24757532513387162396356f7/machines/cache-value.js#L86-L107
// > Note: Redis expects string values, so we serialize `value` to JSON…
// > even if it is already a string.  (This is important for seamless reversibility.)
// > Also note that TTL is seconds, not ms…  I know it's weird -- sorry!
await sails.getDatastore('cache').leaseConnection(async (db)=>{
  await (util.promisify(db.setex).bind(db))(key, ttlInSeconds, JSON.stringify(value));
});//¬

Note that the leased connection (db) is just a Redis client instance. No need to connect it/bind event listeners-- it's already hot and ready to go. Any fatal, unexpected errors that would normally be emitted as the "error" event are handled by the underlying driver, and can be optionally handled with custom logic by providing a function for onUnexpectedFailure.

Need to use a different Redis client, like ioredis? Please have a look at the underlying driver for the latest info/discussion.

Using the Redis client instance

The documentation for the version of redis used in this adapter can be found here: https://github.com/NodeRedis/node_redis/tree/v.2.8.0#sending-commands

Configuration

This adapter supports standard datastore configuration, as well as some additional low-level options.

For example, in a Sails app, add the config below to your config/datastores.js file:

cache: {
  adapter: 'sails-redis',
  url: 'redis://localhost:6379',

  // Other available low-level options can also be configured here.
  // (see below for more information)
},

Note that you probably shouldn't set Redis as the default datastore for your application (your models wouldn't work!)

Low-Level Configuration (for redis client)

Configuration for the underlying Redis client itself is located as an object under the options. The following options are available:

• parser: which Redis protocol reply parser to use. Defaults to hiredis if that module is installed. This may also be set to javascript.
• return_buffers: defaults to false. If set to true, then all replies will be sent to callbacks as node Buffer objects instead of JavaScript Strings.
• detect_buffers: default to false. If set to true, then replies will be sent to callbacks as node Buffer objects if any of the input arguments to the original command were Buffer objects. This option lets you switch between Buffers and Strings on a per-command basis, whereas return_buffers applies to every command on a client.
• socket_nodelay: defaults to true. Whether to call setNoDelay() on the TCP stream, which disables the Nagle algorithm on the underlying socket. Setting this option to false can result in additional throughput at the cost of more latency. Most applications will want this set to true.
• no_ready_check: defaults to false. When a connection is established to the Redis server, the server might still be loading the database from disk. While loading, the server not respond to any commands. To work around this, node_redis has a "ready check" which sends the INFO command to the server. The response from the INFO command indicates whether the server is ready for more commands. When ready, node_redis emits a ready event. Setting no_ready_check to true will inhibit this check.
• enable_offline_queue: defaults to true. By default, if there is no active connection to the redis server, commands are added to a queue and are executed once the connection has been established. Setting enable_offline_queue to false will disable this feature and the callback will be execute immediately with an error, or an error will be thrown if no callback is specified.
• retry_max_delay: defaults to null. By default every time the client tries to connect and fails time before reconnection (delay) almost doubles. This delay normally grows infinitely, but setting retry_max_delay limits delay to maximum value, provided in milliseconds.
• connect_timeout defaults to false. By default client will try reconnecting until connected. Setting connect_timeout limits total time for client to reconnect. Value is provided in milliseconds and is counted once the disconnect occured.
• max_attempts defaults to null. By default client will try reconnecting until connected. Setting max_attempts limits total amount of reconnects.
• auth_pass defaults to null. By default client will try connecting without auth. If set, client will run redis auth command on connect.

Help

For more examples, or if you get stuck or have questions, click here.

Bugs  

To report a bug, click here.

Contributing  

Please observe the guidelines and conventions laid out in the Sails project contribution guide when opening issues or submitting pull requests.

Acknowledgements

I owe a big thank you to @ryanc1256 for all of his work with the original version of this adapter.

License

This adapter, like the Sails framework, is free and open-source under the MIT License.