Support i18n in CC

This patch includes the code to introduce i18n into CC, contains:
(1). i18n init code
(2). Change the base controller to accept new HTTP_ACCEPT_LANGUAGE param
     which identifies the locale of request client
(3). Enhanced ApiError class to translate the error message for REST API
     response.

This patch does not include concrete REST API controller changes to
enable i18n. The changes of concrete REST API controllers' changes
will be submitted in other patches.

Gemfile

@@ -7,6 +7,7 @@ gem 'rake'
 gem 'bcrypt-ruby'
 gem 'eventmachine', '~> 1.0.0'
 gem 'fog'
+gem 'i18n'
 gem 'nokogiri', '~> 1.6.2'
 gem 'unf'
 gem 'netaddr'

Gemfile.lock

@@ -257,6 +257,7 @@ DEPENDENCIES
   fakefs
   fog
   httpclient
+  i18n
   loggregator_emitter (~> 3.0)
   machinist (~> 1.0.6)
   membrane (~> 1.0)

app/controllers/base/base_controller.rb

@@ -70,6 +70,7 @@ def inject_dependencies(dependencies = {})
     # body string], or just a body string.
     def dispatch(op, *args)
       logger.debug "cc.dispatch", endpoint: op, args: args
+      I18n.locale = env['HTTP_ACCEPT_LANGUAGE']
       check_authentication(op)
       send(op, *args)
     rescue Sequel::ValidationFailed => e

lib/cloud_controller/config.rb

@@ -168,6 +168,8 @@ class Config < VCAP::Config
         ],
 
         optional(:app_bits_upload_grace_period_in_seconds) => Integer,
+
+        optional(:default_locale) => String
       }
     end
 
@@ -235,6 +237,7 @@ def merge_defaults(config)
         config[:billing_event_writing_enabled] = true if config[:billing_event_writing_enabled].nil?
         config[:skip_cert_verify] = false if config[:skip_cert_verify].nil?
         config[:app_bits_upload_grace_period_in_seconds] ||= 0
+        config[:default_locale] ||= "en_US"
         sanitize(config)
       end
 

lib/cloud_controller/runner.rb

@@ -1,5 +1,7 @@
 require "steno"
 require "optparse"
+require "i18n"
+require "i18n/backend/fallbacks"
 require "vcap/uaa_token_decoder"
 require "vcap/uaa_verification_key"
 require "cf_message_bus/message_bus"
@@ -26,10 +28,18 @@ def initialize(argv)
       @config_file = File.expand_path("../../../config/cloud_controller.yml", __FILE__)
       parse_options!
       parse_config
+
+      init_i18n
 
       @log_counter = Steno::Sink::Counter.new
     end
 
+    def init_i18n
+      I18n.default_locale = @config[:default_locale]
+      I18n::Backend::Simple.send(:include, I18n::Backend::Fallbacks)
+      I18n.load_path = Dir[File.expand_path("../../../vendor/errors/i18n/*.yml", __FILE__)]
+    end
+
     def logger
       @logger ||= Steno.logger("cc.runner")
     end

lib/vcap/errors/api_error.rb

@@ -16,7 +16,12 @@ def message
         formatted_args = args.map do |arg|
           (arg.is_a? Array) ? arg.map(&:to_s).join(', ') : arg.to_s
         end
-        sprintf(details.message_format, *formatted_args)
+
+        begin
+          sprintf(I18n.translate(details.name, raise: true, :locale => I18n.locale), *formatted_args)
+        rescue I18n::MissingTranslationData => e
+          sprintf(details.message_format, *formatted_args)
+        end
       end
 
       def code

spec/fixtures/i18n/en_US.yml

@@ -0,0 +1,4 @@
+---
+en_US:
+  ServiceInvalid: "This is a translated message of %s %s."
+  MessagePartialTranslated: "This is a translated message of %s %s only in default locale"

spec/fixtures/i18n/zh_CN.yml

@@ -0,0 +1,3 @@
+---
+zh_CN:
+  ServiceInvalid: "这是一条被翻译的信息：%s %s。"

spec/unit/controllers/base/base_controller_spec.rb

@@ -15,6 +15,7 @@
       let(:token_decoder) { double(:decoder) }
       let(:header_token) { 'some token' }
       let(:token_info) { {'user_id' => 'some user'} }
+      let(:env) { {'HTTP_ACCEPT_LANGUAGE' => 'en_US'} }
 
       before do
         configurer = VCAP::CloudController::Security::SecurityContextConfigurer.new(token_decoder)
@@ -27,6 +28,12 @@
         subject.dispatch(:to_s, [:a, :b])
       end
 
+      it "should record the locale during dispatching the request" do
+        expect(subject).to receive(:to_s).with([:a, :b])
+        subject.dispatch(:to_s, [:a, :b])
+        expect(I18n.locale).to eq(:en_US)
+      end
+
       it "should log a debug message" do
         expect(logger).to receive(:debug).with("cc.dispatch", endpoint: :to_s, args: [])
         subject.dispatch(:to_s)

spec/unit/lib/cloud_controller/config_spec.rb

@@ -42,6 +42,10 @@ module VCAP::CloudController
         it "sets a default value for app_bits_upload_grace_period_in_seconds" do
           expect(config[:app_bits_upload_grace_period_in_seconds]).to eq(0)
         end
+
+        it "sets a default value for default_loacle" do
+          expect(config[:default_locale]).to eq("en_US")
+        end
       end
 
       context "when config values are provided" do

spec/unit/lib/cloud_controller/runner_spec.rb

@@ -271,7 +271,6 @@ module VCAP::CloudController
       let (:argv_options) { [] }
 
       before do
-        allow_any_instance_of(Runner).to receive(:parse_config)
         allow_any_instance_of(Runner).to receive(:deprecation_warning)
       end
 
@@ -290,10 +289,10 @@ module VCAP::CloudController
         describe "Configuration File" do
           ["-c", "--config"].each do |flag|
             describe flag do
-              let (:argv_options) { [flag, "config/minimal_config.yml"] }
+              let (:argv_options) { [flag, config_file.path] }
 
               it "should set the configuration file" do
-                expect(subject.config_file).to eq("config/minimal_config.yml")
+                expect(subject.config_file).to eq(config_file.path)
               end
             end
           end
@@ -318,6 +317,10 @@ module VCAP::CloudController
           end
         end
       end
+
+      it "should initialize the i18n framework" do
+        expect(I18n.default_locale).to eq(:en_US)
+      end
     end
 
     describe "#start_thin_server" do

spec/unit/lib/vcap/errors/api_error_spec.rb

@@ -1,25 +1,38 @@
+# coding: utf-8
+
 require 'spec_helper'
 
 module VCAP::Errors
   describe ApiError do
-    let(:details) do
+    def create_details(message)
       double(Details,
-             name: "ServiceInvalid",
+             name: message,
              response_code: 400,
              code: 12345,
              message_format: "Before %s %s after.")
     end
 
-    let(:name) { "ServiceInvalid" }
+    let(:messageServiceInvalid) { "ServiceInvalid" }
+    let(:messagePartialTranslated) { "MessagePartialTranslated"}
+    let(:messageNotTranslated) { "MessageNotTranslated" }
+    let(:args) { [ "foo", "bar" ] }
+
+    let(:messageServiceInvalidDetails) { create_details(messageServiceInvalid) }
+    let(:messagePartialTranslatedDetails) { create_details(messagePartialTranslated) }
+    let(:messageNotTranslatedDetails) { create_details(messageNotTranslated) }
+
+    I18n.default_locale = :en_US
+    I18n::Backend::Simple.send(:include, I18n::Backend::Fallbacks)
+    I18n.load_path = Dir[File.expand_path("../../../../fixtures/i18n/*.yml", File.dirname(__FILE__))]
 
     before do
-      allow(Details).to receive("new").with(name).and_return(details)
+      allow(Details).to receive("new").with(messageServiceInvalid).and_return(messageServiceInvalidDetails)
+      allow(Details).to receive("new").with(messagePartialTranslated).and_return(messagePartialTranslatedDetails)
+      allow(Details).to receive("new").with(messageNotTranslated).and_return(messageNotTranslatedDetails)
     end
 
     context ".new_from_details" do
-      let(:args) { [ "foo", "bar" ] }
-
-      subject(:api_error) { ApiError.new_from_details(name, *args) }
+      subject(:api_error) { ApiError.new_from_details(messageServiceInvalid, *args) }
 
       it "returns an ApiError" do
         expect(api_error).to be_a(ApiError)
@@ -29,12 +42,8 @@ module VCAP::Errors
         expect(api_error).to be_a(Exception)
       end
 
-      it "sets the message using the format provided in the v2.yml" do
-        expect(api_error.message).to eq("Before foo bar after.")
-      end
-
       context "if it doesn't recognise the error from v2.yml" do
-        let(:name) { "What is this?  I don't know?!!"}
+        let(:messageServiceInvalid) { "What is this?  I don't know?!!"}
 
         before do
           allow(Details).to receive(:new).and_call_original
@@ -46,11 +55,39 @@ module VCAP::Errors
       end
     end
 
+    context "get error message" do
+      subject(:api_error) { ApiError.new_from_details(messageServiceInvalid, *args) }
+      subject(:api_error_with_partial_translation) { ApiError.new_from_details(messagePartialTranslated, *args) }
+      subject(:api_error_with_translation_missing)  { ApiError.new_from_details(messageNotTranslated, *args) }
+
+      it "should translate the message based on the locale" do
+        I18n.locale = :en_US
+        expect(api_error.message).to eq("This is a translated message of foo bar.")
+        I18n.locale = :zh_CN
+        expect(api_error.message).to eq("这是一条被翻译的信息：foo bar。")
+      end
+
+      it "should use the default locale message when the message is not translated in target locale" do
+        I18n.locale = :zh_CN
+        expect(api_error_with_partial_translation.message).to eq("This is a translated message of foo bar only in default locale")
+      end
+
+      it "should use the default locale message when the locale is not recognized" do
+        I18n.locale = :unknown_locale
+        expect(api_error.message).to eq("This is a translated message of foo bar.")
+      end
+
+      it "should use the original message when the translation is missing" do
+        I18n.locale = :en_US
+        expect(api_error_with_translation_missing.message).to eq("Before foo bar after.")
+      end
+    end
+
     context "with details" do
       subject(:api_error) { ApiError.new }
 
       before do
-        api_error.details = details
+        api_error.details = messageServiceInvalidDetails
       end
 
       it "exposes the code" do