Add feature flag support using Flipper

Gemfile

@@ -13,6 +13,9 @@ gem 'devise', '~> 4.7', '>= 4.7.2'
 gem 'devise_token_auth', '~> 1.2', git: 'https://github.com/lynndylanhurley/devise_token_auth'
 gem 'draper', '~> 4.0', '>= 4.0.1'
 gem 'exception_hunter', github: 'rootstrap/exception_hunter'
+gem 'flipper', '~> 0.28.0'
+gem 'flipper-active_record', '~> 0.28.0'
+gem 'flipper-ui', '~> 0.28.0'
 gem 'jbuilder', '~> 2.10'
 gem 'oj', '~> 3.9', '>= 3.9.2'
 gem 'pagy', '~> 4.0'

Gemfile.lock

@@ -186,6 +186,17 @@ GEM
     faker (2.23.0)
       i18n (>= 1.8.11, < 2)
     ffi (1.15.5)
+    flipper (0.28.0)
+      concurrent-ruby (< 2)
+    flipper-active_record (0.28.0)
+      activerecord (>= 4.2, < 8)
+      flipper (~> 0.28.0)
+    flipper-ui (0.28.0)
+      erubi (>= 1.0.0, < 2.0.0)
+      flipper (~> 0.28.0)
+      rack (>= 1.4, < 3)
+      rack-protection (>= 1.5.3, <= 4.0.0)
+      sanitize (< 7)
     font-awesome-sass (5.15.1)
       sassc (>= 1.11)
     formtastic (4.0.0)
@@ -296,6 +307,8 @@ GEM
     rack (2.2.6.4)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
+    rack-protection (3.0.6)
+      rack
     rack-test (2.0.2)
       rack (>= 1.3)
     rails (7.0.4.3)
@@ -401,6 +414,9 @@ GEM
       rubocop (>= 0.72, < 2)
     ruby-progressbar (1.11.0)
     ruby2_keywords (0.0.5)
+    sanitize (6.0.1)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.12.0)
     sass-rails (6.0.0)
       sassc-rails (~> 2.1, >= 2.1.1)
     sassc (2.4.0)
@@ -437,8 +453,6 @@ GEM
     timeout (0.3.2)
     tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
-    tzinfo-data (1.2023.3)
-      tzinfo (>= 1.0.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
     unicode-display_width (1.8.0)
@@ -479,6 +493,9 @@ DEPENDENCIES
   exception_hunter!
   factory_bot_rails (~> 5.1, >= 5.1.1)
   faker (~> 2.13)
+  flipper (~> 0.28.0)
+  flipper-active_record (~> 0.28.0)
+  flipper-ui (~> 0.28.0)
   i18n-tasks (~> 0.9.30)
   jbuilder (~> 2.10)
   letter_opener (~> 1.7)

README.md

@@ -21,6 +21,7 @@ This template comes with:
   - Reset password
   - Get and update user profile
 - Administration panel for users
+- Feature flags support with a UI for management.
 - RSpec tests
 - Code quality tools
 - API documentation following https://apiblueprint.org/
@@ -79,6 +80,7 @@ To illustrate, `bin/rails console` will run the console in the docker container
 - [ExceptionHunter](https://github.com/rootstrap/exception_hunter) for exception tracking
 - [Factory Bot](https://github.com/thoughtbot/factory_bot) for testing data
 - [Faker](https://github.com/stympy/faker) for generating test data
+- [Flipper](https://github.com/jnunemaker/flipper) for feature flag support
 - [Jbuilder](https://github.com/rails/jbuilder) for json views
 - [Letter Opener](https://github.com/ryanb/letter_opener) for previewing a mail in the browser
 - [Oj](https://github.com/ohler55/oj) for optimized json

config/initializers/active_admin.rb

@@ -229,12 +229,12 @@
   #
   # If you wanted to add a static menu item to the default menu provided:
   #
-  #   config.namespace :admin do |admin|
-  #     admin.build_menu :default do |menu|
-  #       menu.add label: "My Great Website",
-  #                url: "http://www.mygreatwebsite.com", html_options: { target: :blank }
-  #     end
-  #   end
+  config.namespace :admin do |admin|
+    admin.build_menu :default do |menu|
+      menu.add label: 'Feature Flags',
+               url: '/admin/feature-flags', html_options: { target: :blank }
+    end
+  end
 
   # == Download Links
   #

config/routes.rb

@@ -1,6 +1,11 @@
 Rails.application.routes.draw do
   devise_for :admin_users, ActiveAdmin::Devise.config
   ActiveAdmin.routes(self)
+  namespace :admin do
+    authenticate(:admin_user) do
+      mount Flipper::UI.app(Flipper) => '/feature-flags'
+    end
+  end
   ExceptionHunter.routes(self)
   mount_devise_token_auth_for 'User', at: '/api/v1/users', controllers: {
     registrations: 'api/v1/registrations',

db/migrate/20230704182448_create_flipper_tables.rb

@@ -0,0 +1,22 @@
+class CreateFlipperTables < ActiveRecord::Migration[7.0]
+  def self.up
+    create_table :flipper_features do |t|
+      t.string :key, null: false
+      t.timestamps null: false
+    end
+    add_index :flipper_features, :key, unique: true
+
+    create_table :flipper_gates do |t|
+      t.string :feature_key, null: false
+      t.string :key, null: false
+      t.string :value
+      t.timestamps null: false
+    end
+    add_index :flipper_gates, %i[feature_key key value], unique: true
+  end
+
+  def self.down
+    drop_table :flipper_gates
+    drop_table :flipper_features
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2022_09_05_200553) do
+ActiveRecord::Schema[7.0].define(version: 2023_07_04_182448) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
   enable_extension "plpgsql"
@@ -102,6 +102,22 @@
     t.index ["error_group_id"], name: "index_exception_hunter_errors_on_error_group_id"
   end
 
+  create_table "flipper_features", force: :cascade do |t|
+    t.string "key", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["key"], name: "index_flipper_features_on_key", unique: true
+  end
+
+  create_table "flipper_gates", force: :cascade do |t|
+    t.string "feature_key", null: false
+    t.string "key", null: false
+    t.string "value"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["feature_key", "key", "value"], name: "index_flipper_gates_on_feature_key_and_key_and_value", unique: true
+  end
+
   create_table "settings", force: :cascade do |t|
     t.string "key", null: false
     t.string "value"

spec/rails_helper.rb

@@ -24,6 +24,7 @@
 RSpec.configure do |config|
   config.render_views = true
   config.include Devise::Test::ControllerHelpers, type: :controller
+  config.include Devise::Test::IntegrationHelpers, type: :request
   config.include ActiveJob::TestHelper
   config.use_transactional_fixtures = true
   config.infer_spec_type_from_file_location!

spec/requests/api/v1/feature_flags_spec.rb

@@ -0,0 +1,33 @@
+describe 'GET admin/feature-flags', type: :request do
+  subject { get '/admin/feature-flags' }
+
+  context 'with an admin_user account' do
+    let(:user) { create :admin_user }
+
+    context 'with a valid session' do
+      before { sign_in user }
+
+      it 'shows the feature flags page' do
+        is_expected.to redirect_to('/admin/feature-flags/features')
+      end
+    end
+
+    context 'without a valid session' do
+      it 'redirects the user to the admin login page' do
+        is_expected.to redirect_to('/admin/login')
+      end
+    end
+  end
+
+  context 'with a user account' do
+    let(:user) { create :user }
+
+    context 'with a valid session' do
+      before { sign_in user }
+
+      it 'blocks user access to the feature flags page' do
+        is_expected.not_to redirect_to('/admin/feature-flags/features')
+      end
+    end
+  end
+end