Add support for API message localization

Add support for doing language resolution for a request, based on the
Accept-Language HTTP header.

Using the lazy gettext functionality from oslo gettextutils, it is now
possible to use the resolved language to translate an exception message
to the user requested language and return that translation from the API.

Partially implements bp user-locale-api

Change-Id: Ib2c8360372996d53b50542df54a52d92b07295ca

bin/cinder-all

@@ -44,7 +44,7 @@ if os.path.exists(os.path.join(possible_topdir, "cinder", "__init__.py")):
     sys.path.insert(0, possible_topdir)
 
 from cinder.openstack.common import gettextutils
-gettextutils.install('cinder')
+gettextutils.install('cinder', lazy=True)
 
 from cinder.common import config  # Need to register global_opts
 from cinder.openstack.common import log as logging

bin/cinder-api

@@ -24,7 +24,6 @@
 # eventlet is updated/released to fix the root issue
 
 import eventlet
-
 eventlet.monkey_patch()
 
 import os
@@ -39,7 +38,7 @@ if os.path.exists(os.path.join(possible_topdir, "cinder", "__init__.py")):
     sys.path.insert(0, possible_topdir)
 
 from cinder.openstack.common import gettextutils
-gettextutils.install('cinder')
+gettextutils.install('cinder', lazy=True)
 
 from cinder.common import config  # Need to register global_opts
 from cinder.openstack.common import log as logging

cinder/api/openstack/wsgi.py

@@ -1,6 +1,7 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
 # Copyright 2011 OpenStack LLC.
+# Copyright 2013 IBM Corp.
 # All Rights Reserved.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -21,6 +22,7 @@ import time
 import webob
 
 from cinder import exception
+from cinder.openstack.common import gettextutils
 from cinder.openstack.common import jsonutils
 from cinder.openstack.common import log as logging
 from cinder import utils
@@ -101,6 +103,12 @@ class Request(webob.Request):
 
         return content_type
 
+    def best_match_language(self):
+        """Determines best available locale from the Accept-Language header."""
+        all_languages = gettextutils.get_available_languages('cinder')
+        return self.accept_language.best_match(all_languages,
+                                               default_match='en_US')
+
 
 class ActionDispatcher(object):
     """Maps method name to local methods through action name."""
@@ -1069,12 +1077,15 @@ class Fault(webob.exc.HTTPException):
     def __call__(self, req):
         """Generate a WSGI response based on the exception passed to ctor."""
         # Replace the body with fault details.
+        locale = req.best_match_language()
         code = self.wrapped_exc.status_int
         fault_name = self._fault_names.get(code, "computeFault")
+        explanation = self.wrapped_exc.explanation
         fault_data = {
             fault_name: {
                 'code': code,
-                'message': self.wrapped_exc.explanation}}
+                'message': gettextutils.get_localized_message(explanation,
+                                                              locale)}}
         if code == 413:
             retry = self.wrapped_exc.headers['Retry-After']
             fault_data[fault_name]['retryAfter'] = retry
@@ -1134,13 +1145,19 @@ class OverLimitFault(webob.exc.HTTPException):
 
     @webob.dec.wsgify(RequestClass=Request)
     def __call__(self, request):
-        """
-        Return the wrapped exception with a serialized body conforming to our
-        error format.
-        """
+        """Serializes the wrapped exception conforming to our error format."""
         content_type = request.best_match_content_type()
         metadata = {"attributes": {"overLimitFault": "code"}}
 
+        def translate(msg):
+            locale = request.best_match_language()
+            return gettextutils.get_localized_message(msg, locale)
+
+        self.content['overLimitFault']['message'] = \
+            translate(self.content['overLimitFault']['message'])
+        self.content['overLimitFault']['details'] = \
+            translate(self.content['overLimitFault']['details'])
+
         xml_serializer = XMLDictSerializer(metadata, XMLNS_V1)
         serializer = {
             'application/xml': xml_serializer,

cinder/tests/api/middleware/test_faults.py

@@ -17,12 +17,12 @@
 
 from xml.dom import minidom
 
-import webob
 import webob.dec
 import webob.exc
 
 from cinder.api import common
 from cinder.api.openstack import wsgi
+from cinder.openstack.common import gettextutils
 from cinder.openstack.common import jsonutils
 from cinder import test
 
@@ -109,6 +109,27 @@ class TestFaults(test.TestCase):
         self.assertTrue('resizeNotAllowed' not in resp.body)
         self.assertTrue('forbidden' in resp.body)
 
+    def test_raise_localized_explanation(self):
+        params = ('blah', )
+        expl = gettextutils.Message("String with params: %s" % params, 'test')
+
+        def _mock_translation(msg, locale):
+            return "Mensaje traducido"
+
+        self.stubs.Set(gettextutils,
+                       "get_localized_message", _mock_translation)
+
+        @webob.dec.wsgify
+        def raiser(req):
+            raise wsgi.Fault(webob.exc.HTTPNotFound(explanation=expl))
+
+        req = webob.Request.blank('/.xml')
+        resp = req.get_response(raiser)
+        self.assertEqual(resp.content_type, "application/xml")
+        self.assertEqual(resp.status_int, 404)
+        self.assertTrue(("Mensaje traducido") in resp.body)
+        self.stubs.UnsetAll()
+
     def test_fault_has_status_int(self):
         """Ensure the status_int is set correctly on faults"""
         fault = wsgi.Fault(webob.exc.HTTPBadRequest(explanation='what?'))

cinder/tests/api/openstack/test_wsgi.py

@@ -87,6 +87,21 @@ class RequestTest(test.TestCase):
         result = request.best_match_content_type()
         self.assertEqual(result, "application/json")
 
+    def test_best_match_language(self):
+        # Here we test that we are actually invoking language negotiation
+        # by webob and also that the default locale always available is en-US
+        request = wsgi.Request.blank('/')
+        accepted = 'unknown-lang'
+        request.headers = {'Accept-Language': accepted}
+
+        def fake_best_match(self, offers, default_match=None):
+            return default_match
+
+        self.stubs.SmartSet(request.accept_language,
+                            'best_match', fake_best_match)
+
+        self.assertEqual(request.best_match_language(), 'en_US')
+
 
 class ActionDispatcherTest(test.TestCase):
     def test_dispatch(self):

cinder/utils.py

@@ -48,6 +48,7 @@ from oslo.config import cfg
 
 from cinder import exception
 from cinder.openstack.common import excutils
+from cinder.openstack.common import gettextutils
 from cinder.openstack.common import importutils
 from cinder.openstack.common import lockutils
 from cinder.openstack.common import log as logging
@@ -659,6 +660,8 @@ def utf8(value):
     """
     if isinstance(value, unicode):
         return value.encode('utf-8')
+    elif isinstance(value, gettextutils.Message):
+        return unicode(value).encode('utf-8')
     elif isinstance(value, str):
         return value
     else:

cinder/wsgi.py

@@ -204,7 +204,8 @@ class Server(object):
                                         backlog=backlog)
         self._server = eventlet.spawn(self._start)
         (self._host, self._port) = self._socket.getsockname()[0:2]
-        LOG.info(_("Started %(name)s on %(_host)s:%(_port)s") % self.__dict__)
+        LOG.info(_("Started %(name)s on %(host)s:%(port)s") %
+                 {'name': self.name, 'host': self.host, 'port': self.port})
 
     @property
     def host(self):