
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 comes with an admin dashboard for changing configurations on the fly and is lightweight.
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
mount Sail::Engine => '/sail'
Running the install generator will create necessary migrations for having the settings in your database.
$ rails g sail:install
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.
config.back_link_path = 'root_path' # Path method as string for the "Main app" button in the dashboard. Any non-existent path will make the button disappear
end
Populating the database
In order to create settings, use the config/sail.yml file (or create your own data migrations).
After settings have been created a first time, they will not be updated with the values in the yaml file (otherwise it would defeat the purpose of being able to configure the application without requiring a deploy).
# Rails.root/config/sail.yml
# Setting name with it's information contained inside
first_setting:
description: My very first setting
value: some_important_string
cast_type: string
second_setting:
description: My second setting, this time a boolean
value: false
cast_type: boolean
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']
Contributing
Please refer to this simple guideline.