Dalli (memcached) adapter

.travis.yml

@@ -9,6 +9,7 @@ script: bundle exec rake
 services:
   - redis-server
   - mongodb
+  - memcached
 env:
   - RAILS_VERSION=5.0.0.beta3
   - RAILS_VERSION=4.2.5

Gemfile

@@ -15,6 +15,7 @@ gem 'rack-test', '~> 0.6.3'
 gem 'sqlite3', '~> 1.3.11'
 gem 'rails', "~> #{ENV["RAILS_VERSION"] || '4.2.5'}"
 gem 'minitest', '~> 5.8.0'
+gem 'dalli'
 
 # for active support tests in test/ and only needed for ruby 2.2.x
 gem 'test-unit', '~> 3.0'

lib/flipper/adapters/dalli.rb

@@ -0,0 +1,75 @@
+require 'dalli'
+
+module Flipper
+  module Adapters
+    # Internal: Adapter that wraps another adapter with the ability to cache
+    # adapter calls in Memcached using the Dalli gem.
+    class Dalli
+      include Flipper::Adapter
+      FeaturesKey = :flipper_features
+
+      #Internal
+      attr_accessor :cache
+
+      #Public: The name of the adapter.
+      attr_accessor :name
+
+      # Public
+      def initialize(adapter, cache, ttl = 0)
+        @adapter = adapter
+        @name = adapter.name
+        @cache = cache
+        @ttl = ttl
+      end
+
+      # Public
+      def features
+        @cache.fetch(FeaturesKey, @ttl) do
+          @adapter.features
+        end
+      end
+
+      # Public
+      def add(feature)
+        result = @adapter.add(feature)
+        @cache.delete(FeaturesKey)
+        result
+      end
+
+      # Public
+      def remove(feature)
+        result = @adapter.remove(feature)
+        @cache.delete(FeaturesKey)
+        result
+      end
+
+      # Public
+      def clear(feature)
+        result = @adapter.clear(feature)
+        @cache.delete(feature)
+        result
+      end
+
+      # Public
+      def get(feature)
+        @cache.fetch(feature, @ttl) do
+          @adapter.get(feature)
+        end
+      end
+
+      # Public
+      def enable(feature, gate, thing)
+        result = @adapter.enable(feature, gate, thing)
+        @cache.delete(feature)
+        result
+      end
+
+      # Public
+      def disable(feature, gate, thing)
+        result = @adapter.disable(feature, gate, thing)
+        @cache.delete(feature)
+        result
+      end
+    end
+  end
+end

test/adapters/dalli_test.rb

@@ -0,0 +1,17 @@
+require 'test_helper'
+require 'flipper/adapters/memory'
+require 'flipper/adapters/dalli'
+
+class DalliTest < MiniTest::Test
+  prepend SharedAdapterTests
+
+  def setup
+    @cache = Dalli::Client.new('localhost:11211')
+    memory_adapter = Flipper::Adapters::Memory.new
+    @adapter = Flipper::Adapters::Dalli.new(memory_adapter, @cache)
+  end
+
+  def teardown
+    @cache.flush
+  end
+end