Well-formed exception types for 413 & 503.

Fixes bug 952618

Raise well-formed exception types when 413 or 503
status returned to client.

Change-Id: I26118ff7ec7ba968b303435287d0eb3ff4bd443f

glance/common/client.py

@@ -521,6 +521,10 @@ class BaseClient(object):
                 raise TypeError('Unsupported image type: %s' % body.__class__)
 
             res = c.getresponse()
+
+            def _retry(res):
+                return res.getheader('Retry-After')
+
             status_code = self.get_status_code(res)
             if status_code in self.OK_RESPONSE_CODES:
                 return res
@@ -538,8 +542,13 @@ class BaseClient(object):
                 raise exception.Invalid(res.read())
             elif status_code == httplib.MULTIPLE_CHOICES:
                 raise exception.MultipleChoices(body=res.read())
+            elif status_code == httplib.REQUEST_ENTITY_TOO_LARGE:
+                raise exception.LimitExceeded(retry=_retry(res),
+                                              body=res.read())
             elif status_code == httplib.INTERNAL_SERVER_ERROR:
                 raise Exception("Internal Server error: %s" % res.read())
+            elif status_code == httplib.SERVICE_UNAVAILABLE:
+                raise exception.ServiceUnavailable(retry=_retry(res))
             else:
                 raise Exception("Unknown error occurred! %s" % res.read())
 

glance/common/exception.py

@@ -143,6 +143,28 @@ class MultipleChoices(GlanceException):
                 "request URI.\n\nThe body of response returned:\n%(body)s")
 
 
+class LimitExceeded(GlanceException):
+    message = _("The request returned a 413 Request Entity Too Large. This "
+                "generally means that rate limiting or a quota threshold was "
+                "breached.\n\nThe response body:\n%(body)s")
+
+    def __init__(self, *args, **kwargs):
+        self.retry_after = (int(kwargs['retry']) if kwargs.get('retry')
+                            else None)
+        super(LimitExceeded, self).__init__(*args, **kwargs)
+
+
+class ServiceUnavailable(GlanceException):
+    message = _("The request returned a 503 ServiceUnavilable. This "
+                "generally occurs on service overload or other transient "
+                "outage.")
+
+    def __init__(self, *args, **kwargs):
+        self.retry_after = (int(kwargs['retry']) if kwargs.get('retry')
+                            else None)
+        super(ServiceUnavailable, self).__init__(*args, **kwargs)
+
+
 class InvalidContentType(GlanceException):
     message = _("Invalid content type %(content_type)s")
 

glance/tests/functional/test_client_exceptions.py

@@ -0,0 +1,101 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack, LLC
+# Copyright 2012 Red Hat, Inc
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Functional test asserting strongly typed exceptions from glance client"""
+
+import eventlet.patcher
+import webob.dec
+import webob.exc
+
+from glance.common import client
+from glance.common import exception
+from glance.common import wsgi
+from glance.tests import functional
+from glance.tests import utils
+
+
+eventlet.patcher.monkey_patch(socket=True)
+
+
+class ExceptionTestApp(object):
+    """
+    Test WSGI application which can respond with multiple kinds of HTTP
+    status codes
+    """
+
+    @webob.dec.wsgify
+    def __call__(self, request):
+        path = request.path_qs
+
+        if path == "/rate-limit":
+            request.response = webob.exc.HTTPRequestEntityTooLarge()
+
+        elif path == "/rate-limit-retry":
+            request.response.retry_after = 10
+            request.response.status = 413
+
+        if path == "/service-unavailable":
+            request.response = webob.exc.HTTPServiceUnavailable()
+
+        elif path == "/service-unavailable-retry":
+            request.response.retry_after = 10
+            request.response.status = 503
+
+
+class TestClientExceptions(functional.FunctionalTest):
+
+    def setUp(self):
+        super(TestClientExceptions, self).setUp()
+        self.port = utils.get_unused_port()
+        server = wsgi.Server()
+        conf = utils.TestConfigOpts({'bind_host': '127.0.0.1'})
+        server.start(ExceptionTestApp(), conf, self.port)
+        self.client = client.BaseClient("127.0.0.1", self.port)
+
+    def _do_test_exception(self, path, exc_type):
+        try:
+            self.client.do_request("GET", path)
+            self.fail('expected %s' % exc_type)
+        except exc_type as e:
+            self.assertEquals('retry' in path, e.retry_after == 10)
+
+    def test_rate_limited(self):
+        """
+        Test rate limited response
+        """
+        self._do_test_exception('/rate-limit', exception.LimitExceeded)
+
+    def test_rate_limited_retry(self):
+        """
+        Test rate limited response with retry
+        """
+        self._do_test_exception('/rate-limit-retry', exception.LimitExceeded)
+
+    def test_service_unavailable(self):
+        """
+        Test service unavailable response
+        """
+        self._do_test_exception('/service-unavailable',
+                                exception.ServiceUnavailable)
+
+    def test_service_unavailable_retry(self):
+        """
+        Test service unavailable response with retry
+        """
+        self._do_test_exception('/service-unavailable-retry',
+                                exception.ServiceUnavailable)