Add i18n middleware, fixes #750

Changes.md

@@ -1,6 +1,9 @@
 2.8.0
 -----------
 
+- I18n support!  Sidekiq can optionally save and restore the Rails locale
+  so it will be properly set when your jobs execute.  Just include
+  `require 'sidekiq/middleware/i18n'` in your sidekiq initializer. [#750]
 - Fix bug which could lose messages when using namespaces and the message
 needs to be requeued in Redis. [#744]
 - Refactor Redis namespace support [#747].  The redis namespace can no longer be

lib/sidekiq/middleware/i18n.rb

@@ -0,0 +1,35 @@
+module Sidekiq::Middleware::I18n
+  # Get the current locale and store it in the message
+  # to be sent to Sidekiq.
+  class Client
+    def call(worker_class, msg, queue)
+      msg['locale'] = I18n.locale
+      yield
+    end
+  end
+
+  # Pull the msg locale out and set the current thread to use it.
+  class Server
+    def call(worker, msg, queue)
+      I18n.locale = msg['locale'] || I18n.default_locale
+      yield
+    ensure
+      I18n.locale = nil
+    end
+  end
+end
+
+Sidekiq.configure_client do |config|
+  config.client_middleware do |chain|
+    chain.add Sidekiq::Middleware::I18n::Client
+  end
+end
+
+Sidekiq.configure_server do |config|
+  config.client_middleware do |chain|
+    chain.add Sidekiq::Middleware::I18n::Client
+  end
+  config.server_middleware do |chain|
+    chain.add Sidekiq::Middleware::I18n::Server
+  end
+end

test/test_middleware.rb

@@ -99,4 +99,28 @@ class TestMiddleware < MiniTest::Unit::TestCase
       assert_equal [], recorder
     end
   end
+
+  describe 'i18n' do
+    before do
+      require 'i18n'
+      require 'sidekiq/middleware/i18n'
+    end
+
+    it 'saves and restores locale' do
+      I18n.locale = 'fr'
+      msg = {}
+      mw = Sidekiq::Middleware::I18n::Client.new
+      mw.call(nil, msg, nil) { }
+      assert_equal :fr, msg['locale']
+
+      msg['locale'] = 'jp'
+      I18n.locale = nil
+      assert_equal :en, I18n.locale
+      mw = Sidekiq::Middleware::I18n::Server.new
+      mw.call(nil, msg, nil) do
+        assert_equal :jp, I18n.locale
+      end
+      assert_equal :en, I18n.locale
+    end
+  end
 end