Thread safety for memoizable.

lib/flipper/adapters/memoizable.rb

@@ -5,32 +5,31 @@ module Adapters
     class Memoizable < Decorator
       FeaturesKey = :flipper_features
 
-      # Private: The cache of memoized adapter operations and results.
-      attr_reader :cache
+      # Internal
+      def self.cache
+        Thread.current[:flipper_memoize_cache] ||= {}
+      end
 
-      # Public
-      def initialize(adapter, cache = nil)
-        super(adapter)
-        @cache = cache || {}
+      # Internal
+      def self.memoizing?
+        !!Thread.current[:flipper_memoize]
       end
 
-      # Public: Turns local caching on/off.
-      #
-      # value - The Boolean that decides if local caching is on.
-      def memoize=(value)
+      # Internal
+      def self.memoize=(value)
         cache.clear
-        @memoize = value
+        Thread.current[:flipper_memoize] = value
       end
 
-      # Public: Returns true for using local cache, false for not.
-      def memoizing?
-        !!@memoize
+      # Public
+      def initialize(adapter)
+        super(adapter)
       end
 
       # Public
       def get(feature)
         if memoizing?
-          @cache.fetch(feature) { @cache[feature] = super }
+          cache.fetch(feature) { cache[feature] = super }
         else
           super
         end
@@ -39,22 +38,22 @@ def get(feature)
       # Public
       def enable(feature, gate, thing)
         result = super
-        @cache.delete(feature) if memoizing?
+        cache.delete(feature) if memoizing?
         result
       end
 
       # Public
       def disable(feature, gate, thing)
         result = super
-        @cache.delete(feature) if memoizing?
+        cache.delete(feature) if memoizing?
         result
       end
 
       # Public
       def features
         if memoizing?
-          @cache.fetch(FeaturesKey) {
-            @cache[FeaturesKey] = super
+          cache.fetch(FeaturesKey) {
+            cache[FeaturesKey] = super
           }
         else
           super
@@ -64,9 +63,26 @@ def features
       # Public
       def add(feature)
         result = super
-        @cache.delete(FeaturesKey) if memoizing?
+        cache.delete(FeaturesKey) if memoizing?
         result
       end
+
+      # Internal
+      def cache
+        self.class.cache
+      end
+
+      # Internal: Turns local caching on/off.
+      #
+      # value - The Boolean that decides if local caching is on.
+      def memoize=(value)
+        self.class.memoize = value
+      end
+
+      # Internal: Returns true for using local cache, false for not.
+      def memoizing?
+        self.class.memoizing?
+      end
     end
   end
 end

spec/flipper/adapters/memoizable_spec.rb

@@ -6,11 +6,15 @@
 describe Flipper::Adapters::Memoizable do
   let(:features_key) { described_class::FeaturesKey }
 
-  let(:cache)   { {} }
   let(:adapter) { Flipper::Adapters::Memory.new }
   let(:flipper) { Flipper.new(adapter) }
+  let(:cache) { Thread.current[:flipper_memoize_cache] }
 
-  subject { described_class.new(adapter, cache) }
+  after do
+    described_class.memoize = nil
+  end
+
+  subject { described_class.new(adapter) }
 
   it_should_behave_like 'a flipper adapter'
 

spec/flipper/middleware/local_cache_spec.rb

@@ -30,6 +30,10 @@
     end.to_app
   }
 
+  after do
+    flipper.adapter.memoize = nil
+  end
+
   it "delegates" do
     called = false
     app = lambda { |env|