Support table prefixes in ActiveRecord adapter

lib/flipper/adapters/active_record.rb

@@ -24,6 +24,7 @@ class ActiveRecord
       # name - The Symbol name for this adapter. Optional (default :active_record)
       # feature_class - The AR class responsible for the features table.
       # gate_class - The AR class responsible for the gates table.
+      # table_prefix - The prefix for the default features and gates tables.
       #
       # Allowing the overriding of name is so you can differentiate multiple
       # instances of this adapter from each other, if, for some reason, that is
@@ -33,8 +34,13 @@ class ActiveRecord
       # can roll your own tables and what not, if you so desire.
       def initialize(options = {})
         @name = options.fetch(:name, :active_record)
-        @feature_class = options.fetch(:feature_class) { Flipper::Adapters::ActiveRecord::Feature }
-        @gate_class = options.fetch(:gate_class) { Flipper::Adapters::ActiveRecord::Gate }
+        table_prefix = options[:table_prefix]
+        @feature_class = options.fetch(:feature_class) do
+          model_class(Flipper::Adapters::ActiveRecord::Feature, table_prefix, "flipper_features")
+        end
+        @gate_class = options.fetch(:gate_class) do
+          model_class(Flipper::Adapters::ActiveRecord::Gate, table_prefix, "flipper_gates")
+        end
       end
 
       # Public: The set of known features.
@@ -190,6 +196,14 @@ def unsupported_data_type(data_type)
 
       private
 
+      def model_class(default_class, table_prefix, table_name)
+        return default_class if table_prefix.nil?
+
+        Class.new(default_class) do
+          self.table_name = "#{table_prefix}#{table_name}"
+        end
+      end
+
       def set(feature, gate, thing, options = {})
         clear_feature = options.fetch(:clear, false)
         json_feature = options.fetch(:json, false)

lib/generators/flipper/active_record_generator.rb

@@ -1,9 +1,11 @@
 require 'rails/generators/active_record'
+require 'generators/flipper/table_prefix'
 
 module Flipper
   module Generators
     class ActiveRecordGenerator < ::Rails::Generators::Base
       include ::Rails::Generators::Migration
+      include Flipper::Generators::TablePrefix
       desc 'Generates migration for flipper tables'
 
       source_paths << File.join(File.dirname(__FILE__), 'templates')
@@ -24,7 +26,8 @@ def create_migration_file
         options = {
           migration_version: migration_version,
         }
-        migration_template 'migration.erb', 'db/migrate/create_flipper_tables.rb', options
+        destination = File.join('db/migrate', prefixed_migration_file_name('create_flipper_tables.rb'))
+        migration_template 'migration.erb', destination, options
       end
 
       def migration_version

lib/generators/flipper/table_prefix.rb

@@ -0,0 +1,44 @@
+require 'active_support/core_ext/string/inflections'
+
+module Flipper
+  module Generators
+    module TablePrefix
+      def self.included(generator)
+        generator.class_option :table_prefix,
+                               type: :string,
+                               default: '',
+                               desc: 'Prefix for the flipper_features and flipper_gates tables'
+      end
+
+      private
+
+      def feature_table_name
+        :"#{table_prefix}flipper_features"
+      end
+
+      def gate_table_name
+        :"#{table_prefix}flipper_gates"
+      end
+
+      def prefixed_migration_file_name(file_name)
+        file_name.sub('flipper', "#{table_prefix}flipper")
+      end
+
+      def migration_class_name(class_name)
+        class_name.sub('Flipper', "#{table_prefix.camelize}Flipper")
+      end
+
+      def feature_index_name
+        :"index_#{table_prefix}flipper_features_on_key" unless table_prefix.empty?
+      end
+
+      def gate_index_name
+        :"index_#{table_prefix}flipper_gates_on_keys" unless table_prefix.empty?
+      end
+
+      def table_prefix
+        options[:table_prefix].to_s
+      end
+    end
+  end
+end

lib/generators/flipper/templates/migration.erb

@@ -1,22 +1,28 @@
-class CreateFlipperTables < ActiveRecord::Migration<%= migration_version %>
+<%
+migration_class = respond_to?(:migration_class_name, true) ? migration_class_name('CreateFlipperTables') : 'CreateFlipperTables'
+feature_table = respond_to?(:feature_table_name, true) ? feature_table_name : :flipper_features
+gate_table = respond_to?(:gate_table_name, true) ? gate_table_name : :flipper_gates
+feature_index = respond_to?(:feature_index_name, true) ? feature_index_name : nil
+gate_index = respond_to?(:gate_index_name, true) ? gate_index_name : nil
+%>class <%= migration_class %> < ActiveRecord::Migration<%= migration_version %>
   def up
-    create_table :flipper_features do |t|
+    create_table <%= feature_table.inspect %> do |t|
       t.string :key, null: false
       t.timestamps null: false
     end
-    add_index :flipper_features, :key, unique: true
+    add_index <%= feature_table.inspect %>, :key, unique: true<%= ", name: #{feature_index.inspect}" if feature_index %>
 
-    create_table :flipper_gates do |t|
+    create_table <%= gate_table.inspect %> do |t|
       t.string :feature_key, null: false
       t.string :key, null: false
       t.text :value
       t.timestamps null: false
     end
-    add_index :flipper_gates, [:feature_key, :key, :value], unique: true, length: { value: 255 }
+    add_index <%= gate_table.inspect %>, [:feature_key, :key, :value], unique: true, length: { value: 255 }<%= ", name: #{gate_index.inspect}" if gate_index %>
   end
 
   def down
-    drop_table :flipper_gates
-    drop_table :flipper_features
+    drop_table <%= gate_table.inspect %>
+    drop_table <%= feature_table.inspect %>
   end
 end

lib/generators/flipper/templates/update/migrations/01_create_flipper_tables.rb.erb

@@ -1,22 +1,28 @@
-class CreateFlipperTables < ActiveRecord::Migration<%= migration_version %>
+<%
+migration_class = migration_class_name('CreateFlipperTables')
+feature_table = feature_table_name
+gate_table = gate_table_name
+feature_index = feature_index_name
+gate_index = gate_index_name
+%>class <%= migration_class %> < ActiveRecord::Migration<%= migration_version %>
   def up
-    create_table :flipper_features do |t|
+    create_table <%= feature_table.inspect %> do |t|
       t.string :key, null: false
       t.timestamps null: false
     end
-    add_index :flipper_features, :key, unique: true
+    add_index <%= feature_table.inspect %>, :key, unique: true<%= ", name: #{feature_index.inspect}" if feature_index %>
 
-    create_table :flipper_gates do |t|
+    create_table <%= gate_table.inspect %> 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, [:feature_key, :key, :value], unique: true
+    add_index <%= gate_table.inspect %>, [:feature_key, :key, :value], unique: true<%= ", name: #{gate_index.inspect}" if gate_index %>
   end
 
   def down
-    drop_table :flipper_gates
-    drop_table :flipper_features
+    drop_table <%= gate_table.inspect %>
+    drop_table <%= feature_table.inspect %>
   end
 end

lib/generators/flipper/templates/update/migrations/02_change_flipper_gates_value_to_text.rb.erb

@@ -1,18 +1,23 @@
 # frozen_string_literal: true
 
-class ChangeFlipperGatesValueToText < ActiveRecord::Migration<%= migration_version %>
+<%
+migration_class = migration_class_name('ChangeFlipperGatesValueToText')
+gate_table = gate_table_name
+gate_index = gate_index_name
+%>class <%= migration_class %> < ActiveRecord::Migration<%= migration_version %>
   def up
     # Ensure this incremental update migration is idempotent
-    return unless connection.column_exists? :flipper_gates, :value, :string
+    return unless connection.column_exists? <%= gate_table.inspect %>, :value, :string
 
-    if index_exists? :flipper_gates, [:feature_key, :key, :value]
-      remove_index :flipper_gates, [:feature_key, :key, :value]
+    gate_index = connection.indexes(<%= gate_table.inspect %>).find do |index|
+      index.columns == %w[feature_key key value]
     end
-    change_column :flipper_gates, :value, :text
-    add_index :flipper_gates, [:feature_key, :key, :value], unique: true, length: { value: 255 }
+    remove_index <%= gate_table.inspect %>, name: gate_index.name if gate_index
+    change_column <%= gate_table.inspect %>, :value, :text
+    add_index <%= gate_table.inspect %>, [:feature_key, :key, :value], unique: true, length: { value: 255 }<%= ", name: #{gate_index.inspect}" if gate_index %>
   end
 
   def down
-    change_column :flipper_gates, :value, :string
+    change_column <%= gate_table.inspect %>, :value, :string
   end
 end

lib/generators/flipper/update_generator.rb

@@ -2,6 +2,7 @@
 
 require 'rails/generators'
 require 'rails/generators/active_record'
+require 'generators/flipper/table_prefix'
 
 module Flipper
   module Generators
@@ -11,6 +12,7 @@ module Generators
     #
     class UpdateGenerator < Rails::Generators::Base
       include ActiveRecord::Generators::Migration
+      include Flipper::Generators::TablePrefix
 
       TEMPLATES = File.join(File.dirname(__FILE__), 'templates/update')
       source_paths << TEMPLATES
@@ -21,6 +23,7 @@ def update_migration_files
         migration_templates = Dir.children(File.join(TEMPLATES, 'migrations')).sort
         migration_templates.each do |template_file|
           destination_file = template_file.match(/^\d*_(.*\.rb)/)[1] # 01_create_flipper_tables.rb.erb => create_flipper_tables.rb
+          destination_file = prefixed_migration_file_name(destination_file)
           migration_template "migrations/#{template_file}", File.join(db_migrate_path, destination_file), skip: true
         end
       end

test/adapters/active_record_test.rb

@@ -41,6 +41,46 @@ def setup
   def teardown
     ActiveRecord::Base.connection.execute("DROP table IF EXISTS `flipper_features`")
     ActiveRecord::Base.connection.execute("DROP table IF EXISTS `flipper_gates`")
+    ActiveRecord::Base.connection.execute("DROP table IF EXISTS `cross_product_flipper_features`")
+    ActiveRecord::Base.connection.execute("DROP table IF EXISTS `cross_product_flipper_gates`")
+  end
+
+  def test_table_prefix_uses_internal_model_subclasses
+    ActiveRecord::Base.connection.execute <<-SQL
+      CREATE TABLE cross_product_flipper_features (
+        id integer PRIMARY KEY,
+        key text NOT NULL UNIQUE,
+        created_at datetime NOT NULL,
+        updated_at datetime NOT NULL
+      )
+    SQL
+
+    ActiveRecord::Base.connection.execute <<-SQL
+      CREATE TABLE cross_product_flipper_gates (
+        id integer PRIMARY KEY,
+        feature_key text NOT NULL,
+        key text NOT NULL,
+        value text DEFAULT NULL,
+        created_at datetime NOT NULL,
+        updated_at datetime NOT NULL
+      )
+    SQL
+
+    adapter = Flipper::Adapters::ActiveRecord.new(table_prefix: "cross_product_")
+    feature_class = adapter.instance_variable_get(:@feature_class)
+    gate_class = adapter.instance_variable_get(:@gate_class)
+
+    assert_operator feature_class, :<, Flipper::Adapters::ActiveRecord::Feature
+    assert_operator gate_class, :<, Flipper::Adapters::ActiveRecord::Gate
+    assert_equal "cross_product_flipper_features", feature_class.table_name
+    assert_equal "cross_product_flipper_gates", gate_class.table_name
+
+    flipper = Flipper.new(adapter)
+    flipper[:search].enable
+
+    assert flipper[:search].enabled?
+    assert_equal ["search"], feature_class.pluck(:key)
+    assert_equal [["search", "boolean", "true"]], gate_class.pluck(:feature_key, :key, :value)
   end
 
   def test_models_honor_table_name_prefixes_and_suffixes

test_rails/generators/flipper/active_record_generator_test.rb

@@ -38,4 +38,37 @@ def down
       end
     MIGRATION
   end
+
+  def test_generates_migration_with_table_prefix
+    run_generator ["--table-prefix=cross_product_"]
+    migration_version = if Rails::VERSION::MAJOR.to_i < 5
+                          ""
+                        else
+                          "[#{Rails::VERSION::MAJOR}.#{Rails::VERSION::MINOR}]"
+                        end
+    assert_migration 'db/migrate/create_cross_product_flipper_tables.rb', <<~MIGRATION
+      class CreateCrossProductFlipperTables < ActiveRecord::Migration#{migration_version}
+        def up
+          create_table :cross_product_flipper_features do |t|
+            t.string :key, null: false
+            t.timestamps null: false
+          end
+          add_index :cross_product_flipper_features, :key, unique: true, name: :index_cross_product_flipper_features_on_key
+
+          create_table :cross_product_flipper_gates do |t|
+            t.string :feature_key, null: false
+            t.string :key, null: false
+            t.text :value
+            t.timestamps null: false
+          end
+          add_index :cross_product_flipper_gates, [:feature_key, :key, :value], unique: true, length: { value: 255 }, name: :index_cross_product_flipper_gates_on_keys
+        end
+
+        def down
+          drop_table :cross_product_flipper_gates
+          drop_table :cross_product_flipper_features
+        end
+      end
+    MIGRATION
+  end
 end

test_rails/generators/flipper/update_generator_test.rb

@@ -82,10 +82,42 @@ class UpdateGeneratorTest < Rails::Generators::TestCase
     assert ActiveRecord::Base.connection.column_exists?(:flipper_gates, :value, :text)
   end
 
+  test "generates migrations with a table prefix" do
+    run_generator ["--table-prefix=cross_product_"]
+
+    assert_migration "db/migrate/create_cross_product_flipper_tables.rb" do |migration|
+      assert_match(/class CreateCrossProductFlipperTables/, migration)
+      assert_match(/create_table :cross_product_flipper_features/, migration)
+      assert_match(/create_table :cross_product_flipper_gates/, migration)
+      assert_match(/name: :index_cross_product_flipper_gates_on_keys/, migration)
+    end
+
+    assert_migration "db/migrate/change_cross_product_flipper_gates_value_to_text.rb" do |migration|
+      assert_match(/class ChangeCrossProductFlipperGatesValueToText/, migration)
+      assert_match(/column_exists\? :cross_product_flipper_gates/, migration)
+      assert_match(/connection.indexes\(:cross_product_flipper_gates\)/, migration)
+      assert_match(/remove_index :cross_product_flipper_gates, name: gate_index.name/, migration)
+      assert_match(/change_column :cross_product_flipper_gates/, migration)
+      assert_match(/name: :index_cross_product_flipper_gates_on_keys/, migration)
+    end
+
+    require_migrations
+
+    silence { CreateCrossProductFlipperTables.migrate(:up) }
+    assert ActiveRecord::Base.connection.table_exists?(:cross_product_flipper_features)
+    assert ActiveRecord::Base.connection.table_exists?(:cross_product_flipper_gates)
+    assert ActiveRecord::Base.connection.column_exists?(:cross_product_flipper_gates, :value, :string)
+
+    silence { ChangeCrossProductFlipperGatesValueToText.migrate(:up) }
+    assert ActiveRecord::Base.connection.column_exists?(:cross_product_flipper_gates, :value, :text)
+  end
+
   def require_migrations
     # If these are not reloaded, then test order can cause failures
     Object.send(:remove_const, :CreateFlipperTables) if defined?(::CreateFlipperTables)
     Object.send(:remove_const, :ChangeFlipperGatesValueToText) if defined?(::ChangeFlipperGatesValueToText)
+    Object.send(:remove_const, :CreateCrossProductFlipperTables) if defined?(::CreateCrossProductFlipperTables)
+    Object.send(:remove_const, :ChangeCrossProductFlipperGatesValueToText) if defined?(::ChangeCrossProductFlipperGatesValueToText)
 
     Dir.glob("#{ROOT}/db/migrate/*.rb").each do |file|
       assert_nothing_raised do