Redis stores for Ruby on Rails

redis-rails provides a full set of stores (Cache, Session, HTTP Cache) for Ruby on Rails. See the main redis-store readme for general guidelines.

A quick note about Rails 5.2

Rails 5.2.0 includes a Redis cache store out of the box, so you don't really need this gem anymore if you just need to store the fragment cache in Redis. Maintenence on the redis-activesupport gem will continue for security and compatibility issues, but we are no longer accepting new features. We are still actively maintaining all other gems in the redis-store family.

Installation

Add the following to your Gemfile:

gem 'redis-rails'

Usage

# config/application.rb
config.cache_store = :redis_store, "redis://localhost:6379/0/cache", { expires_in: 90.minutes }

(NOTE: The :expires_in option can also be written as :expire_in and :expire_after)

To be fault tolerant when redis is not available you can set option raise_errors to false since redis-activesupport v4.1.4.

Configuration values at the end are optional. If you want to use Redis as a backend for sessions, you will also need to set:

# config/initializers/session_store.rb
MyApplication::Application.config.session_store :redis_store, servers: ["redis://localhost:6379/0/session"]

You can also provide a hash instead of a URL

config.cache_store = :redis_store, {
  host: "localhost",
  port: 6379,
  db: 0,
  password: "mysecret",
  namespace: "cache"
}

And similarly for the session store:

MyApplication::Application.config.session_store :redis_store, {
  servers: [
    {
      host: "localhost",
      port: 6379,
      db: 0,
      password: "mysecret",
      namespace: "session"
    },
  ],
  expire_after: 90.minutes,
  key: "_#{Rails.application.class.parent_name.downcase}_session"
}

NOTE: The sessions store uses a global lock to ensure operations are atomic. No atomic guarantees can be made if you're running multiple instances of your app, so it is recommended that you disable this by using the threadsafe: false option.

And if you would like to use Redis as a rack-cache backend for HTTP caching, add redis-rack-cache to your Gemfile and add:

# config/environments/production.rb
config.action_dispatch.rack_cache = {
  metastore: "redis://localhost:6379/1/metastore",
  entitystore: "redis://localhost:6379/1/entitystore"
}

Usage with Redis Sentinel

sentinel_config = {
  url: "redis://mymaster/0",
  role: "master",
  sentinels: [{
    host: "127.0.0.1",
    port: 26379
  },{
    host: "127.0.0.1",
    port: 26380
  },{
    host: "127.0.0.1",
    port: 26381
  }]
}

# configure cache, merging opts with sentinel conf
config.cache_store = :redis_store, sentinel_config.merge(
  namespace: "cache",
  expires_in: 1.days
)

# configure sessions, setting the sentinel config as the
# servers value, merging opts with the sentinel conf.
config.session_store :redis_store, {
  servers: [
    sentinel_config.merge(
      namespace: "sessions"
    )
  ],
  expire_after: 2.days
}

Usage with Redis Cluster

Although there isn't an official redis cluster client for ruby, many teams use a redis cluster proxy. Often, redis cluster proxies do not support the MULTI command which might contain keys belonging to different masters. To get around this problem, you can use the avoid_multi_commands: true option. This will tell redis store to use the redis gem's pipelined feature instead of a MULTI command. You should only use this if your redis cluster proxy fails to process MULTI commands.

Running tests

gem install bundler
git clone git://github.com/redis-store/redis-rails.git
cd redis-rails
RAILS_VERSION=5.0.1 bundle install
RAILS_VERSION=5.0.1 bundle exec rake

If you are on Snow Leopard you have to run env ARCHFLAGS="-arch x86_64" bundle exec rake

Status

Copyright

2009 - 2011 Luca Guidi - http://lucaguidi.com, released under the MIT license

angelfan/redis-rails