settings-in-redis

This gem provides a Settings module that is written to be API-compatible with the v1.x ledermann-rails-settings gem for the management of global settings.

The Settings module manages key-value pairs that are stored in Redis. Each setting is stored as a key with a string value in Redis. You can store any kind of object which can be serialized as YAML.

Installation

Include the gem in your Gemfile

gem 'settings-in-redis'

The connection to Redis must be specified for Settings, for example in an initializer:

Settings.redis = Redis.new

Alternatively, a ConnectionPool can be used to share Redis connections among threads:

Settings.redis_pool = ConnectionPool.new { Redis.new }

Setting values are stored in Redis with a default prefix of "settings:".

Usage

The syntax is easy. First create some settings to keep track of:

Settings.admin_password = 'supersecret'
Settings.date_format    = '%m %d, %Y'
Settings.cocktails      = ['Martini', 'Screwdriver', 'White Russian']
Settings.foo            = 123
Settings.credentials    = { :username => 'tom', :password => 'secret' }

Then read them back:

Settings.foo
# => 123

Changing an existing setting is the same as creating a new setting:

Settings.foo = 'super duper bar'

To change an existing setting which is a Hash, you can merge new values with existing ones:

Settings.merge! :credentials, :password => 'topsecret'
Settings.credentials
# => { :username => 'tom', :password => 'topsecret' }

Decide that a particular setting is no longer needed?

Settings.destroy :foo
Settings.foo
# => nil

Want a list of all the settings?

Settings.all
# => { 'admin_password' => 'super_secret', 'date_format' => '%m %d, %Y' }

If you want to group settings and list the settings for a particular namespace, then choose your preferred namespace delimiter and use Settings.all like this:

Settings['preferences.color'] = :blue
Settings['preferences.size'] = :large
Settings['license.key'] = 'ABC-DEF'
Settings.all('preferences.')
# => { 'preferences.color' => :blue, 'preferences.size' => :large }

You can set defaults for certain settings of your app. This will cause the defined settings to return with the specified value even if they are not in Redis. Make a new file in config/initializers/settings.rb with the following:

Settings.defaults[:some_setting] = 'footastic'

Now even if there are not settings in Redis, the app will have some intelligent defaults:

Settings.some_setting
# => 'footastic'

For better performance, you can enable caching, e.g.:

Settings.cache = ActiveSupport::Cache::MemoryStore.new
Settings.cache_options = { :expires_in => 5.minutes }

In our experience, this 5 minute caching was always necessary in a production Rails application where a setting may be used in every request.