featureflow-ruby-sdk

Ruby SDK for featureflow

Featureflow Ruby SDK

Get your Featureflow account at featureflow.io

Get Started

The easiest way to get started is to follow the Featureflow quick start guides

Change Log

Please see CHANGELOG.

Usage

Getting Started

Ruby

Add the following line to your Gemfile

gem 'featureflow'

Requiring featureflow in your ruby application will expose the classes Featureflow::Client, Featuerflow::ContextBuilder and Featureflow::Feature.

The usage of each class is documented below.

Quick start

Get your environment's Featureflow Server API key and initialise a new Featureflow client

FEATUREFLOW_SERVER_KEY = '<Your server api key goes here>'
featureflow = Featureflow::Client.new api_key: FEATUREFLOW_SERVER_KEY

This will load the rules for each feature for the current environment specified by the api key. These rules can be changed at https://<your-org-key>.featureflow.io, and the changes will be applied to your application.

Note: You are responsible for passing the featureflow instance around your application

Defining Context

Before evaluating a feature you must define a context for the current user.
Featureflow uses context to target different user groups to specific feature variants. A featureflow context has a key, which should uniquely identify the current user, and optionally additional values. Featureflow requires the context key to be unique per user for gradual rollout of features.

There are two ways to define context:

require 'featureflow'
context_key = '<unique_user_identifier>'

# option 1, use the context builder
context = Featureflow::ContextBuilder.new(context_key)
                                     .with_values(country: 'US',
                                                  roles: %w[USER_ADMIN, BETA_CUSTOMER])
                                     .build

# option 2, use just a string
context = context_key

Evaluating Features

In your code, you can test the value of your feature using something similar to below For these examples below, assume the feature my-feature-key is equal to 'on' for the current context

if featureflow.evaluate('my-feature-key', context).is? 'on'
  # this code will be run because 'my-feature-key' is set to 'on' for the given context
end

Because the most common variants for a feature are 'on' and 'off', we have provided two helper methods .on? and .off?

if featureflow.evaluate('my-feature-key', context).on?
  # this feature code will be run because 'my-feature-key' is set to 'on'
end

if featureflow.evaluate('my-feature-key', context).off?
  # this feature code won't be run because 'my-feature-key' is not set to 'off'
end

Pre-registering Features

Featureflow allows you to pre-register features that may not be defined in your Featureflow project to ensure that those features are available when that version of your code is running. If in the off-chance your application is unable to access the Featureflow servers and you don't have access to a cached version of the features, you can specify a failover variant for any feature.

The failover variant allows you to control what variant a feature will evaluate to when no rules are available for the feature. If a failover variant isn't defined, each feature will use a default feailover variant of 'off'.

You can pre-register features at the initialisation of your featureflow client like below:

require 'featureflow'

FEATUREFLOW_SERVER_KEY = '<Your server api key goes here>'

featureflow = Featureflow::Client.new(api_key: FEATUREFLOW_SERVER_KEY,
                                      with_features: [
                                        Featureflow::Feature.create('key-one', 'on'),
                                        Featureflow::Feature.create('key-two'),
                                        Featureflow::Feature.create('key-three', 'custom'),
                                      ])

# ... app has been started offline
featureflow.evaluate('key-one', context).on? # == true
featureflow.evaluate('key-two', context).off? # == true
featureflow.evaluate('key-three', context).is? 'custom' # == true

Further documentation

Further documentation can be found here

Roadmap

• [x] Write documentation
• [x] Release to RubyGems
• [ ] Write Ruby on Rails integration

License

Apache-2.0