Feature Flags (#252)

* add flipper feature flags

* fix rubocop

Gemfile

@@ -35,6 +35,9 @@ gem "phonelib"
 gem "audited", "~> 5.3", ">= 5.3.3"
 gem "config", "~> 4.2"
 gem "devise", "~> 4.9"
+gem "flipper"
+gem "flipper-active_record"
+gem "flipper-ui"
 gem "httparty", "~> 0.21"
 gem "invisible_captcha"
 gem "omniauth-azure-activedirectory-v2"

Gemfile.lock

@@ -83,6 +83,7 @@ GEM
     bootsnap (1.16.0)
       msgpack (~> 1.2)
     brakeman (6.0.1)
+    brow (0.4.1)
     builder (3.2.4)
     bundler-audit (0.9.1)
       bundler (>= 1.2.0, < 3)
@@ -169,6 +170,18 @@ GEM
       faraday-net_http (>= 2.0, < 3.1)
       ruby2_keywords (>= 0.0.4)
     faraday-net_http (3.0.2)
+    flipper (1.0.0)
+      brow (~> 0.4.1)
+      concurrent-ruby (< 2)
+    flipper-active_record (1.0.0)
+      activerecord (>= 4.2, < 8)
+      flipper (~> 1.0.0)
+    flipper-ui (1.0.0)
+      erubi (>= 1.0.0, < 2.0.0)
+      flipper (~> 1.0.0)
+      rack (>= 1.4, < 4)
+      rack-protection (>= 1.5.3, <= 4.0.0)
+      sanitize (< 7)
     foreman (0.87.2)
     fugit (1.8.1)
       et-orbi (~> 1, >= 1.2.7)
@@ -381,6 +394,9 @@ GEM
       rubocop-factory_bot (~> 2.22)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
+    sanitize (6.1.0)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.12.0)
     scenic (1.7.0)
       activerecord (>= 4.0.0)
       railties (>= 4.0.0)
@@ -463,6 +479,9 @@ DEPENDENCIES
   dotenv-rails
   factory_bot_rails
   faker
+  flipper
+  flipper-active_record
+  flipper-ui
   foreman
   govuk-components (= 4.1.1)
   govuk_design_system_formbuilder

config/initializers/flipper.rb

@@ -0,0 +1,6 @@
+class CanAccessFlipperUI
+  def self.matches?(request)
+    current_user = request.env["warden"].user
+    current_user.present?
+  end
+end

config/routes.rb

@@ -37,5 +37,9 @@
     resources "reports", only: %i[show index]
     get "/duplicates", to: "applicants#duplicates"
     get "/audits", to: "audits#index"
+
+    constraints CanAccessFlipperUI do
+      mount Flipper::UI.app(Flipper) => "/features"
+    end
   end
 end

db/migrate/20230915092215_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