Sail

This Rails engine brings a setting model into your app to be used as feature flags, gauges, knobs and other live controls you may need.

It saves configurations to the database so that it can be changed while the application is running, without requiring a deploy.

Having this ability enables live experiments and tuning to find an application's best setup.

Enable/Disable a new feature, turn ON/OFF ab testing for new functionality, change jobs' parameters to tune performance, you name it.

It can either serve as an admin control panel or user settings, depending on how you wish to apply it.

Installation

Add this line to your application's Gemfile:

gem 'sail'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sail

Adding the following line to your routes file will make the dashboard available at <base_url>/sail

mount Sail::Engine => '/sail'

Running the generator will create the settings table for your application.

$ rails g sail my_desired_migration_name

Which generates a migration to create the following table

create_table :sail_settings do |t|
  t.string :name, null: false
  t.text :description
  t.string :value, null: false
  t.integer :cast_type, null: false, limit: 1
  t.index ["name"], name: "index_settings_on_name", unique: true
  t.timetamps
end

Configuration

Available configurations and their defaults are listed below

Sail.configure do |config|
  config.cache_life_span = 10.minutes # How long to cache the Sail::Setting.get response for
  config.array_separator = ';'        # Default separator for array settings
  config.dashboard_auth_lambda = nil  # Defines an authorization lambda to access the dashboard as a before action. Rendering or redirecting is included here if desired.
end

Manipulating settings in the code

Settings can be read or set via their interface. Notice that when reading a setting's value, it will be cast to the appropriate type using the "cast_type" field.

Possible cast types are

integer
float
date
string
boolean
ab_test
cron
obj_model
uri
range
array

# Get setting value with appropriate cast type
Sail::Setting.get('name')

# Set setting value
Sail::Setting.set('name', 'value')

Sail also comes with a JSON API for manipulating settings.

GET sail/settings/:name

Response
{
  "value": true
}

PUT sail/settings/:name

Response
200 OK

Examples

# Integer setting
Sail::Setting.create(name: :my_setting, cast_type: :integer, description: 'A very important setting', value: '15')
Sail::Setting.get(:my_setting)
=> 15

# Float setting
Sail::Setting.create(name: :my_setting, cast_type: :float, description: 'A very important setting', value: '1.532')
Sail::Setting.get(:my_setting)
=> 1.532

# Date setting
Sail::Setting.create(name: :my_setting, cast_type: :date, description: 'A very important setting', value: '2018-01-30')
Sail::Setting.get(:my_setting)
=> Tue, 30 Jan 2018 00:00:00 +0000

# String setting
Sail::Setting.create(name: :my_setting, cast_type: :string, description: 'A very important setting', value: '15')
Sail::Setting.get(:my_setting)
=> '15'

# Boolean setting
Sail::Setting.create(name: :my_setting, cast_type: :boolean, description: 'A very important setting', value: 'true')
Sail::Setting.get(:my_setting)
=> true

# AB test setting
# When true, returns true or false randomly. When false, always returns false
Sail::Setting.create(name: :my_setting, cast_type: :ab_test, description: 'A very important setting', value: 'true')
Sail::Setting.get(:my_setting)
=> true

# Cron setting
# if DateTime.now.utc matches the configured cron expression returns true. Returns false for no matches.
Sail::Setting.create(name: :my_setting, cast_type: :cron, description: 'A very important setting', value: '* 15 1 * *')
Sail::Setting.get(:my_setting)
=> true

# Obj model setting
# Will return the model based on the string value
Sail::Setting.create(name: :my_setting, cast_type: :obj_model, description: 'A very important setting', value: 'Post')
Sail::Setting.get(:my_setting)
=> Post

# URI setting
# Returns the URI object for a given string
Sail::Setting.create(name: :my_setting, cast_type: :uri, description: 'A very important setting', value: 'https://google.com')
Sail::Setting.get(:my_setting)
=> <URI::HTTPS https://google.com>

# Range setting (ranges only accept values between 0...100)
Sail::Setting.create(name: :my_setting, cast_type: :range, description: 'A very important setting', value: '99')
Sail::Setting.get(:my_setting)
=> 99

# Array setting
Sail::Setting.create(name: :my_setting, cast_type: :array, description: 'A very important setting', value: 'John;Alfred;Michael')
Sail::Setting.get(:my_setting)
=> ['John', 'Alfred', 'Michael']

Managing your settings live

Sail brings a dashboard so that you can manage your settings and update their values as needed.

Contributing

Please refer to this simple guideline.