add sidekiq middleware component to avoid reusing contexts between wo…

lib/makara.rb

@@ -1,6 +1,9 @@
 require 'active_support'
 require 'makara/version'
-require 'makara/railtie' if defined?(Rails)
+if defined?(Rails)
+  require 'makara/railtie'
+  require 'makara/sidekiq/railtie' if defined?(Sidekiq)
+end
 module Makara
 
   autoload :Cache,              'makara/cache'
@@ -31,6 +34,10 @@ module Strategies
     autoload :PriorityFailover, 'makara/strategies/priority_failover'
   end
 
+  module Sidekiq
+    autoload :Middleware, 'makara/sidekiq/middleware'
+  end
+
 end
 
 ActiveSupport.on_load(:active_record) do

lib/makara/sidekiq/middleware.rb

@@ -0,0 +1,11 @@
+module Makara
+  module Sidekiq
+    class Middleware
+      def call(*args)
+        yield
+      ensure
+        ::Makara::Context.set_current({})
+      end
+    end
+  end
+end

lib/makara/sidekiq/railtie.rb

@@ -0,0 +1,13 @@
+module Makara
+  module Sidekiq
+    class Railtie < ::Rails::Railtie
+      initializer 'makara-sidekiq.insert_middleware' do |app|
+        ::Sidekiq.configure_server do |config|
+          config.server_middleware do |chain|
+            chain.add Makara::Sidekiq::Middleware
+          end
+        end
+      end
+    end
+  end
+end

spec/sidekiq/middleware_spec.rb

@@ -0,0 +1,32 @@
+require 'spec_helper'
+require 'makara/sidekiq/middleware'
+
+describe Makara::Sidekiq::Middleware do
+  let(:worker)  { class_double('Worker') }
+  let(:job)     { Hash.new }
+  let(:queue)   { 'default' }
+
+  shared_examples 'a cleared context' do
+    it 'clears the context' do
+      expect(::Makara::Context).to receive(:set_current).with({})
+
+      subject.call(worker, job, queue) {}
+    end
+  end
+
+  context 'when the worker raises an error' do
+    before do
+      allow_any_instance_of(worker).to receive(:perform).and_raise(ArgumentError)
+    end
+
+    it_behaves_like 'a cleared context'
+  end
+
+  context 'when the worker completes successfully' do
+    before do
+      allow_any_instance_of(worker).to receive(:perform).and_return(true)
+    end
+
+    it_behaves_like 'a cleared context'
+  end
+end