Merge pull request #280 from edx/dsjen/502

Error page will be displayed for 502s from course API.

acceptance_tests/pages.py

@@ -226,3 +226,8 @@ class NotFoundErrorPage(ErrorPage):
 class AccessDeniedErrorPage(ErrorPage):
     error_code = 403
     error_title = u'Access Denied'
+
+
+class BadGatewayErrorPage(ErrorPage):
+    error_code = 502
+    error_title = u"We're having trouble loading this page. Please try again in a minute."

acceptance_tests/test_error_pages.py

@@ -3,12 +3,12 @@
 from bok_choy.web_app_test import WebAppTest
 
 from acceptance_tests import PLATFORM_NAME, APPLICATION_NAME, SUPPORT_URL, ENABLE_ERROR_PAGE_TESTS
-from acceptance_tests.pages import ServerErrorPage, NotFoundErrorPage, AccessDeniedErrorPage
+from acceptance_tests.pages import ServerErrorPage, NotFoundErrorPage, AccessDeniedErrorPage, BadGatewayErrorPage
 
 
 @skipUnless(ENABLE_ERROR_PAGE_TESTS, 'Error page tests are not enabled.')
 class ErrorPagesTests(WebAppTest):
-    error_page_classes = [ServerErrorPage, NotFoundErrorPage, AccessDeniedErrorPage]
+    error_page_classes = [ServerErrorPage, NotFoundErrorPage, AccessDeniedErrorPage, BadGatewayErrorPage]
 
     def test_valid_pages(self):
         for page_class in self.error_page_classes:

analytics_dashboard/core/exceptions.py

@@ -0,0 +1,5 @@
+class BadGatewayError(Exception):
+    """
+    Raise if bad gateway (502).
+    """
+    pass

analytics_dashboard/core/middleware.py

@@ -2,8 +2,15 @@
 Middleware for Language Preferences
 """
 
+import logging
 from lang_pref_middleware import middleware
 
+from django.template.response import TemplateResponse
+
+from core.exceptions import BadGatewayError
+
+logger = logging.getLogger(__name__)
+
 
 class LanguagePreferenceMiddleware(middleware.LanguagePreferenceMiddleware):
     def get_user_language_preference(self, user):
@@ -13,3 +20,14 @@ def get_user_language_preference(self, user):
         Returns None if no preference set.
         """
         return user.language
+
+
+class BadGatewayExceptionMiddleware(object):
+    """
+    Display an error template for 502 errors.
+    """
+
+    def process_exception(self, request, exception):
+        if type(exception) is BadGatewayError:
+            logger.exception(exception)
+            return TemplateResponse(request, '502.html', status=502)

analytics_dashboard/core/tests/test_middleware.py

@@ -1,11 +1,32 @@
-from django.test import TestCase
+import logging
+
+from django.template.response import TemplateResponse
+from django.test import RequestFactory, TestCase
 from django_dynamic_fixture import G
 from lang_pref_middleware.tests import LangPrefMiddlewareTestCaseMixin
+from testfixtures import LogCapture
 
-from core.middleware import LanguagePreferenceMiddleware
+from core.exceptions import BadGatewayError
+from core.middleware import BadGatewayExceptionMiddleware, LanguagePreferenceMiddleware
 from core.models import User
 
 
+class MiddlewareTestCase(TestCase):
+    middleware_class = None
+
+    def setUp(self):
+        super(MiddlewareTestCase, self).setUp()
+        self.factory = RequestFactory()
+        self.middleware = self.middleware_class()   # pylint: disable=not-callable
+
+
+class MiddlewareAssertionMixin(object):
+    def assertStandardExceptions(self, request):
+        self.assertIsNone(self.middleware.process_exception(request, None))
+        self.assertIsNone(self.middleware.process_exception(request, Exception))
+        self.assertIsNone(self.middleware.process_exception(request, ArithmeticError))
+
+
 class TestUserLanguagePreferenceMiddleware(LangPrefMiddlewareTestCaseMixin, TestCase):
     middleware_class = LanguagePreferenceMiddleware
 
@@ -15,3 +36,23 @@ def get_user(self):
     def set_user_language_preference(self, user, language):
         user.language = language
         user.save()
+
+
+class BadGatewayMiddlewareTests(MiddlewareAssertionMixin, MiddlewareTestCase):
+    middleware_class = BadGatewayExceptionMiddleware
+
+    def assertIsBadGatewayErrorResponse(self, response):
+        self.assertEqual(response.status_code, 502)
+        self.assertIs(type(response), TemplateResponse)
+        self.assertEqual(response.template_name, '502.html')
+
+    def test_process_exception(self):
+        request = self.factory.get('/')
+        self.assertStandardExceptions(request)
+        with LogCapture(level=logging.WARN) as l:
+            exception = BadGatewayError()
+            response = self.middleware.process_exception(request, exception)
+            self.assertIsBadGatewayErrorResponse(response)
+
+            # Verify the exception was logged
+            l.check(('core.middleware', 'ERROR', str(exception)),)

analytics_dashboard/core/views.py

@@ -110,6 +110,13 @@ def logout_then_login(request, login_url=reverse_lazy('login'), current_app=None
     return django.contrib.auth.views.logout_then_login(request, login_url, current_app, extra_context)
 
 
+class BadGatewayView(TemplateView):
+    """
+    Bad gateway error page requesting users to wait and reload the page.
+    """
+    template_name = "502.html"
+
+
 class LandingView(TemplateView):
     """
     Displays a public landing page when users first come to the site.

analytics_dashboard/courses/tests/test_middleware.py

@@ -1,24 +1,15 @@
 import logging
 
 from django.template.response import TemplateResponse
-from django.test import RequestFactory, TestCase
 from opaque_keys.edx.keys import CourseKey
 from testfixtures import LogCapture
 
+from core.tests.test_middleware import MiddlewareTestCase, MiddlewareAssertionMixin
 from courses.exceptions import PermissionsRetrievalFailedError
 from courses.middleware import CourseMiddleware, CoursePermissionsExceptionMiddleware
 
 
-class MiddlewareTestCase(TestCase):
-    middleware_class = None
-
-    def setUp(self):
-        super(MiddlewareTestCase, self).setUp()
-        self.factory = RequestFactory()
-        self.middleware = self.middleware_class()   # pylint: disable=not-callable
-
-
-class MiddlewareAssertionMixin(object):
+class CoursePermissionsExceptionMixin(MiddlewareAssertionMixin):
     def assertIsPermissionsRetrievalFailedResponse(self, response):
         self.assertEqual(response.status_code, 500)
         self.assertIs(type(response), TemplateResponse)
@@ -49,16 +40,14 @@ def test_course_id(self):
         self.assertEqual(request.course_key, course_key)
 
 
-class CoursePermissionsExceptionMiddlewareTests(MiddlewareAssertionMixin, MiddlewareTestCase):
+class CoursePermissionsExceptionMiddlewareTests(CoursePermissionsExceptionMixin, MiddlewareTestCase):
     middleware_class = CoursePermissionsExceptionMiddleware
 
     def test_process_exception(self):
         request = self.factory.get('/')
 
         # Method should return None if exception argument is NOT PermissionsRetrievalFailedError.
-        self.assertIsNone(self.middleware.process_exception(request, None))
-        self.assertIsNone(self.middleware.process_exception(request, Exception))
-        self.assertIsNone(self.middleware.process_exception(request, ArithmeticError))
+        self.assertStandardExceptions(request)
 
         with LogCapture(level=logging.WARN) as l:
             # Method should only return a response for PermissionsRetrievalFailedError.

analytics_dashboard/courses/tests/test_views/test_pages.py

@@ -9,7 +9,7 @@
     CourseAPIMixin
 
 from courses.exceptions import PermissionsRetrievalFailedError
-from courses.tests.test_middleware import MiddlewareAssertionMixin
+from courses.tests.test_middleware import CoursePermissionsExceptionMixin
 
 
 @ddt
@@ -28,7 +28,7 @@ def test_missing_data(self, course_id):
         self.skipTest('The course homepage does not check for the existence of a course.')
 
 
-class CourseIndexViewTests(CourseAPIMixin, ViewTestMixin, MiddlewareAssertionMixin, TestCase):
+class CourseIndexViewTests(CourseAPIMixin, ViewTestMixin, CoursePermissionsExceptionMixin, TestCase):
     viewname = 'courses:index'
 
     def setUp(self):

analytics_dashboard/courses/views/performance.py

@@ -6,6 +6,7 @@
 from slugify import slugify
 from slumber.exceptions import SlumberBaseException
 
+from core.exceptions import BadGatewayError
 from courses.presenters.performance import CoursePerformancePresenter
 from courses.views import CourseTemplateWithNavView, CourseAPIMixin
 
@@ -40,9 +41,12 @@ def dispatch(self, request, *args, **kwargs):
         except SlumberBaseException as e:
             # Return the appropriate response if a 404 occurred.
             response = getattr(e, 'response')
-            if response is not None and response.status_code == 404:
-                logger.info('Course API data not found for %s: %s', self.course_id, e)
-                raise Http404
+            if response is not None:
+                if response.status_code == 404:
+                    logger.info('Course API data not found for %s: %s', self.course_id, e)
+                    raise Http404
+                elif response.status_code == 502:
+                    raise BadGatewayError
 
             # Not a 404. Continue raising the error.
             logger.error('An error occurred while using Slumber to communicate with an API: %s', e)

analytics_dashboard/help/middleware.py

@@ -9,7 +9,7 @@ class HelpURLMiddleware(object):
 
     def process_template_response(self, _request, response):
         # Error responses do not have context.
-        if response.status_code == 500:
+        if response.status_code in [500, 502]:
             return response
 
         page_token = response.context_data.get(HELP_CONTEXT_TOKEN_NAME)

analytics_dashboard/settings/base.py

@@ -188,6 +188,7 @@
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
     'waffle.middleware.WaffleMiddleware',
     'core.middleware.LanguagePreferenceMiddleware',
+    'core.middleware.BadGatewayExceptionMiddleware',
     'courses.middleware.CourseMiddleware',
     'courses.middleware.CoursePermissionsExceptionMiddleware',
     'social.apps.django_app.middleware.SocialAuthExceptionMiddleware',

analytics_dashboard/templates/502.html

@@ -0,0 +1,11 @@
+{% extends "base-error.html" %}
+
+{% load i18n %}
+
+{% block title %}{% trans "We're having trouble loading this page. Please try again in a minute." %} {{ block.super }}{% endblock title %}
+
+{% block error-title %}{% trans "We're having trouble loading this page. Please try again in a minute." %}{% endblock %}
+{% block error-copy %}
+  {{ block.super }}
+  {% trans "(Technical details: 502 Bad Gateway.)" %}
+{% endblock %}

analytics_dashboard/urls.py

@@ -42,6 +42,7 @@
         url(r'^403/$', 'django.views.defaults.permission_denied'),
         url(r'^404/$', 'django.views.defaults.page_not_found'),
         url(r'^500/$', 'django.views.defaults.server_error'),
+        url(r'^502/$', views.BadGatewayView.as_view(), name='bad_gateway'),
     )
 
     if os.environ.get('ENABLE_DJANGO_TOOLBAR', False):