User messages API for error cases

This patch implements basic user messages with the following APIs.
GET /messages
GET /messages/<message_id>
DELETE /messages/<message_id>

Implements : blueprint summarymessage

Co-Authored-By: Alex Meade <mr.alex.meade@gmail.com>
Co-Authored-By: Sheel Rana <ranasheel2000@gmail.com>

Change-Id: Id8a4a700c1159be24b15056f401a2ea77804d0a0

cinder/api/openstack/api_version_request.py

@@ -49,6 +49,7 @@ REST_API_VERSION_HISTORY = """
     * 3.1 - Adds visibility and protected to _volume_upload_image parameters.
     * 3.2 - Bootable filters in volume GET call no longer treats all values
             passed to it as true.
+    * 3.3 - Add user messages APIs.
 
 """
 
@@ -57,7 +58,7 @@ REST_API_VERSION_HISTORY = """
 # minimum version of the API supported.
 # Explicitly using /v1 or /v2 enpoints will still work
 _MIN_API_VERSION = "3.0"
-_MAX_API_VERSION = "3.2"
+_MAX_API_VERSION = "3.3"
 _LEGACY_API_VERSION1 = "1.0"
 _LEGACY_API_VERSION2 = "2.0"
 

cinder/api/openstack/rest_api_version_history.rst

@@ -51,3 +51,7 @@ user documentation.
   bootable filter values.
   But for any other values passed for bootable filter, it will return
   "Invalid input received: bootable={filter value}' error.
+
+3.3
+---
+  Added /messages API.

cinder/api/v3/messages.py

@@ -0,0 +1,106 @@
+#    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.
+
+"""The messages API."""
+
+
+from oslo_config import cfg
+from oslo_log import log as logging
+import webob
+from webob import exc
+
+from cinder.api.openstack import wsgi
+from cinder.api.v3.views import messages as messages_view
+from cinder import exception
+from cinder.message import api as message_api
+from cinder.message import defined_messages
+import cinder.policy
+
+CONF = cfg.CONF
+
+LOG = logging.getLogger(__name__)
+MESSAGES_BASE_MICRO_VERSION = '3.3'
+
+
+def check_policy(context, action, target_obj=None):
+    target = {
+        'project_id': context.project_id,
+        'user_id': context.user_id,
+    }
+    target.update(target_obj or {})
+
+    _action = 'message:%s' % action
+    cinder.policy.enforce(context, _action, target)
+
+
+class MessagesController(wsgi.Controller):
+    """The User Messages API controller for the OpenStack API."""
+
+    _view_builder_class = messages_view.ViewBuilder
+
+    def __init__(self, ext_mgr):
+        self.message_api = message_api.API()
+        self.ext_mgr = ext_mgr
+        super(MessagesController, self).__init__()
+
+    @wsgi.Controller.api_version(MESSAGES_BASE_MICRO_VERSION)
+    def show(self, req, id):
+        """Return the given message."""
+        context = req.environ['cinder.context']
+
+        try:
+            message = self.message_api.get(context, id)
+        except exception.MessageNotFound as error:
+            raise exc.HTTPNotFound(explanation=error.msg)
+
+        check_policy(context, 'get', message)
+
+        # Fetches message text based on event id passed to it.
+        message['user_message'] = defined_messages.get_message_text(
+            message['event_id'])
+
+        return self._view_builder.detail(req, message)
+
+    @wsgi.Controller.api_version(MESSAGES_BASE_MICRO_VERSION)
+    def delete(self, req, id):
+        """Delete a message."""
+        context = req.environ['cinder.context']
+
+        try:
+            message = self.message_api.get(context, id)
+            check_policy(context, 'delete', message)
+            self.message_api.delete(context, message)
+        except exception.MessageNotFound as error:
+            raise exc.HTTPNotFound(explanation=error.msg)
+
+        return webob.Response(status_int=204)
+
+    @wsgi.Controller.api_version(MESSAGES_BASE_MICRO_VERSION)
+    def index(self, req):
+        """Returns a list of messages, transformed through view builder."""
+        context = req.environ['cinder.context']
+        check_policy(context, 'get_all')
+
+        messages = self.message_api.get_all(context)
+
+        for message in messages:
+            # Fetches message text based on event id passed to it.
+            user_message = defined_messages.get_message_text(
+                message['event_id'])
+            message['user_message'] = user_message
+
+        messages = self._view_builder.index(req, messages)
+        return messages
+
+
+def create_resource(ext_mgr):
+    return wsgi.Resource(MessagesController(ext_mgr))

cinder/api/v3/router.py

@@ -28,6 +28,7 @@ from cinder.api.v2 import snapshot_metadata
 from cinder.api.v2 import snapshots
 from cinder.api.v2 import types
 from cinder.api.v2 import volume_metadata
+from cinder.api.v3 import messages
 from cinder.api.v3 import volumes
 from cinder.api import versions
 
@@ -53,6 +54,11 @@ class APIRouter(cinder.api.openstack.APIRouter):
                         collection={'detail': 'GET'},
                         member={'action': 'POST'})
 
+        self.resources['messages'] = messages.create_resource(ext_mgr)
+        mapper.resource("message", "messages",
+                        controller=self.resources['messages'],
+                        collection={'detail': 'GET'})
+
         self.resources['types'] = types.create_resource()
         mapper.resource("type", "types",
                         controller=self.resources['types'],

cinder/api/v3/views/messages.py

@@ -0,0 +1,69 @@
+#    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.
+
+
+from cinder.api import common
+
+
+class ViewBuilder(common.ViewBuilder):
+    """Model a server API response as a python dictionary."""
+
+    _collection_name = "messages"
+
+    def index(self, request, messages, message_count=None):
+        """Show a list of messages."""
+        return self._list_view(self.detail, request, messages, message_count)
+
+    def detail(self, request, message):
+        """Detailed view of a single message."""
+        message_ref = {
+            'id': message.get('id'),
+            'event_id': message.get('event_id'),
+            'user_message': message.get('user_message'),
+            'message_level': message.get('message_level'),
+            'created_at': message.get('created_at'),
+            'guaranteed_until': message.get('expires_at'),
+            'request_id': message.get('request_id'),
+            'links': self._get_links(request, message['id']),
+        }
+
+        if message.get('resource_type'):
+            message_ref['resource_type'] = message.get('resource_type')
+        if message.get('resource_uuid'):
+            message_ref['resource_uuid'] = message.get('resource_uuid')
+
+        return {'message': message_ref}
+
+    def _list_view(self, func, request, messages, message_count=None,
+                   coll_name=_collection_name):
+        """Provide a view for a list of messages.
+
+        :param func: Function used to format the message data
+        :param request: API request
+        :param messages: List of messages in dictionary format
+        :param message_count: Length of the original list of messages
+        :param coll_name: Name of collection, used to generate the next link
+                          for a pagination query
+        :returns: message data in dictionary format
+        """
+        messages_list = [func(request, message)['message']
+                         for message in messages]
+        messages_links = self._get_collection_links(request,
+                                                    messages,
+                                                    coll_name,
+                                                    message_count)
+        messages_dict = dict(messages=messages_list)
+
+        if messages_links:
+            messages_dict['messages_links'] = messages_links
+
+        return messages_dict

cinder/db/api.py

@@ -1121,6 +1121,28 @@ def image_volume_cache_get_all_for_host(context, host):
 ###################
 
 
+def message_get(context, message_id):
+    """Return a message with the specified ID."""
+    return IMPL.message_get(context, message_id)
+
+
+def message_get_all(context):
+    return IMPL.message_get_all(context)
+
+
+def message_create(context, values):
+    """Creates a new message with the specified values."""
+    return IMPL.message_create(context, values)
+
+
+def message_destroy(context, message_id):
+    """Deletes message with the specified ID."""
+    return IMPL.message_destroy(context, message_id)
+
+
+###################
+
+
 def get_model_for_versioned_object(versioned_object):
     return IMPL.get_model_for_versioned_object(versioned_object)
 

cinder/db/sqlalchemy/api.py

@@ -4271,6 +4271,76 @@ def purge_deleted_rows(context, age_in_days):
 ###############################
 
 
+def _translate_messages(messages):
+    return [_translate_message(message) for message in messages]
+
+
+def _translate_message(message):
+    """Translate the Message model to a dict."""
+    return {
+        'id': message['id'],
+        'project_id': message['project_id'],
+        'request_id': message['request_id'],
+        'resource_type': message['resource_type'],
+        'resource_uuid': message.get('resource_uuid'),
+        'event_id': message['event_id'],
+        'message_level': message['message_level'],
+        'created_at': message['created_at'],
+        'expires_at': message.get('expires_at'),
+    }
+
+
+@require_context
+def message_get(context, message_id):
+    query = model_query(context,
+                        models.Message,
+                        read_deleted="no",
+                        project_only="yes")
+    result = query.filter_by(id=message_id).first()
+    if not result:
+        raise exception.MessageNotFound(message_id=message_id)
+    return _translate_message(result)
+
+
+@require_context
+def message_get_all(context):
+    """Fetch all messages for the contexts project."""
+    messages = models.Message
+    query = (model_query(context,
+                         messages,
+                         read_deleted="no",
+                         project_only="yes"))
+    results = query.all()
+    return _translate_messages(results)
+
+
+@require_context
+def message_create(context, values):
+    message_ref = models.Message()
+    if not values.get('id'):
+        values['id'] = str(uuid.uuid4())
+    message_ref.update(values)
+
+    session = get_session()
+    with session.begin():
+        session.add(message_ref)
+
+
+@require_admin_context
+def message_destroy(context, message):
+    session = get_session()
+    now = timeutils.utcnow()
+    with session.begin():
+        (model_query(context, models.Message, session=session).
+            filter_by(id=message.get('id')).
+            update({'deleted': True,
+                    'deleted_at': now,
+                    'updated_at': literal_column('updated_at')}))
+
+
+###############################
+
+
 @require_context
 def driver_initiator_data_update(context, initiator, namespace, updates):
     session = get_session()

cinder/db/sqlalchemy/migrate_repo/versions/074_add_message_table.py

@@ -0,0 +1,40 @@
+#   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.
+
+from sqlalchemy import Boolean, Column, DateTime
+from sqlalchemy import MetaData, String, Table
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+
+    # New table
+    messages = Table(
+        'messages',
+        meta,
+        Column('id', String(36), primary_key=True, nullable=False),
+        Column('project_id', String(36), nullable=False),
+        Column('request_id', String(255), nullable=False),
+        Column('resource_type', String(36)),
+        Column('resource_uuid', String(255), nullable=True),
+        Column('event_id', String(255), nullable=False),
+        Column('message_level', String(255), nullable=False),
+        Column('created_at', DateTime(timezone=False)),
+        Column('updated_at', DateTime(timezone=False)),
+        Column('deleted_at', DateTime(timezone=False)),
+        Column('deleted', Boolean),
+        Column('expires_at', DateTime(timezone=False)),
+        mysql_engine='InnoDB'
+    )
+
+    messages.create()

cinder/db/sqlalchemy/models.py

@@ -599,6 +599,24 @@ class DriverInitiatorData(BASE, models.TimestampMixin, models.ModelBase):
     value = Column(String(255))
 
 
+class Message(BASE, CinderBase):
+    """Represents a message"""
+    __tablename__ = 'messages'
+    id = Column(String(36), primary_key=True, nullable=False)
+    project_id = Column(String(36), nullable=False)
+    # Info/Error/Warning.
+    message_level = Column(String(255), nullable=False)
+    request_id = Column(String(255), nullable=True)
+    resource_type = Column(String(255))
+    # The uuid of the related resource.
+    resource_uuid = Column(String(36), nullable=True)
+    # Operation specific event ID.
+    event_id = Column(String(255), nullable=False)
+    created_at = Column(DateTime, default=lambda: timeutils.utcnow())
+    # After this time the message may no longer exist
+    expires_at = Column(DateTime, nullable=True)
+
+
 class ImageVolumeCacheEntry(BASE, models.ModelBase):
     """Represents an image volume cache entry"""
     __tablename__ = 'image_volume_cache_entries'

cinder/exception.py

@@ -286,6 +286,10 @@ class VolumeNotFound(NotFound):
     message = _("Volume %(volume_id)s could not be found.")
 
 
+class MessageNotFound(NotFound):
+    message = _("Message %(message_id)s could not be found.")
+
+
 class VolumeAttachmentNotFound(NotFound):
     message = _("Volume attachment could not be found with "
                 "filter: %(filter)s .")
@@ -532,6 +536,10 @@ class BackupLimitExceeded(QuotaError):
     message = _("Maximum number of backups allowed (%(allowed)d) exceeded")
 
 
+class ImageLimitExceeded(QuotaError):
+    message = _("Image quota exceeded")
+
+
 class DuplicateSfVolumeNames(Duplicate):
     message = _("Detected more than one volume with name %(vol_name)s")
 

cinder/image/glance.py

@@ -219,6 +219,8 @@ class GlanceClientWrapper(object):
                                           'method': method,
                                           'extra': extra})
                 time.sleep(1)
+            except glanceclient.exc.HTTPOverLimit as e:
+                raise exception.ImageLimitExceeded(e)
 
 
 class GlanceImageService(object):

cinder/message/api.py

@@ -0,0 +1,75 @@
+#    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.
+"""
+Handles all requests related to user facing messages.
+"""
+import datetime
+
+from oslo_config import cfg
+from oslo_log import log as logging
+from oslo_utils import timeutils
+
+from cinder.db import base
+from cinder.i18n import _LE, _LI
+from cinder.message import defined_messages
+
+
+messages_opts = [
+    cfg.IntOpt('message_ttl', default=2592000,
+               help='message minimum life in seconds.')]
+
+CONF = cfg.CONF
+CONF.register_opts(messages_opts)
+
+LOG = logging.getLogger(__name__)
+
+
+class API(base.Base):
+    """API for handling user messages."""
+
+    def create(self, context, event_id, project_id, resource_type=None,
+               resource_uuid=None, level="ERROR"):
+        """Create a message with the specified information."""
+        LOG.info(_LI("Creating message record for request_id = %s"),
+                 context.request_id)
+        # Ensure valid event_id
+        defined_messages.get_message_text(event_id)
+        # Updates expiry time for message as per message_ttl config.
+        expires_at = (timeutils.utcnow() + datetime.timedelta(
+                      seconds=CONF.message_ttl))
+
+        message_record = {'project_id': project_id,
+                          'request_id': context.request_id,
+                          'resource_type': resource_type,
+                          'resource_uuid': resource_uuid,
+                          'event_id': event_id,
+                          'message_level': level,
+                          'expires_at': expires_at}
+        try:
+            self.db.message_create(context, message_record)
+        except Exception:
+            LOG.exception(_LE("Failed to create message record "
+                              "for request_id %s"), context.request_id)
+
+    def get(self, context, id):
+        """Return message with the specified id."""
+        return self.db.message_get(context, id)
+
+    def get_all(self, context):
+        """Return all messages for the given context."""
+        messages = self.db.message_get_all(context)
+        return messages
+
+    def delete(self, context, id):
+        """Delete message with the specified id."""
+        ctx = context.elevated()
+        return self.db.message_destroy(ctx, id)

cinder/message/defined_messages.py

@@ -0,0 +1,44 @@
+#    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.
+
+"""Event ID and user visible message mapping.
+
+Event IDs are used to look up the message to be displayed for an API Message
+object. All defined messages should be appropriate for any API user to see
+and not contain any sensitive information. A good rule-of-thumb is to be very
+general in error messages unless the issue is due to a bad user action, then be
+specific.
+"""
+
+from cinder.i18n import _
+
+UNKNOWN_ERROR = '000001'
+UNABLE_TO_ALLOCATE = '000002'
+ATTACH_READONLY_VOLUME = '000003'
+IMAGE_FROM_VOLUME_OVER_QUOTA = '000004'
+
+event_id_message_map = {
+    UNKNOWN_ERROR: _("An unknown error occurred."),
+    UNABLE_TO_ALLOCATE: _("No storage could be allocated for this volume "
+                          "request. You may be able to try another size or"
+                          " volume type."),
+    ATTACH_READONLY_VOLUME: _("A readonly volume must be attached as "
+                              "readonly."),
+    IMAGE_FROM_VOLUME_OVER_QUOTA: _("Failed to copy volume to image as image "
+                                    "quota has been met. Please delete images"
+                                    " or have your limit increased, then try "
+                                    "again."),
+}
+
+
+def get_message_text(event_id):
+    return event_id_message_map[event_id]

cinder/message/resource_types.py

@@ -0,0 +1,15 @@
+#    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.
+
+"""Resource type constants."""
+
+VOLUME = 'VOLUME'

cinder/opts.py

@@ -44,6 +44,7 @@ from cinder.image import image_utils as cinder_image_imageutils
 import cinder.keymgr
 from cinder.keymgr import conf_key_mgr as cinder_keymgr_confkeymgr
 from cinder.keymgr import key_mgr as cinder_keymgr_keymgr
+from cinder.message import api as cinder_message_api
 from cinder import quota as cinder_quota
 from cinder.scheduler import driver as cinder_scheduler_driver
 from cinder.scheduler import host_manager as cinder_scheduler_hostmanager
@@ -311,6 +312,7 @@ def list_opts():
                 cinder_volume_drivers_zfssa_zfssanfs.ZFSSA_OPTS,
                 cinder_volume_drivers_disco_disco.disco_opts,
                 cinder_volume_drivers_hgst.hgst_opts,
+                cinder_message_api.messages_opts,
                 cinder_image_imageutils.image_helper_opts,
                 cinder_compute_nova.nova_opts,
                 cinder_volume_drivers_ibm_flashsystemfc.flashsystem_fc_opts,

cinder/scheduler/flows/create_volume.py

@@ -18,6 +18,9 @@ from taskflow.patterns import linear_flow
 from cinder import exception
 from cinder import flow_utils
 from cinder.i18n import _LE
+from cinder.message import api as message_api
+from cinder.message import defined_messages
+from cinder.message import resource_types
 from cinder import rpc
 from cinder import utils
 from cinder.volume.flows import common
@@ -90,6 +93,7 @@ class ScheduleCreateVolumeTask(flow_utils.CinderTask):
                                                        **kwargs)
         self.db_api = db_api
         self.driver_api = driver_api
+        self.message_api = message_api.API()
 
     def _handle_failure(self, context, request_spec, cause):
         try:
@@ -127,6 +131,13 @@ class ScheduleCreateVolumeTask(flow_utils.CinderTask):
             # reraise (since what's the point?)
             with excutils.save_and_reraise_exception(
                     reraise=not isinstance(e, exception.NoValidHost)):
+                if isinstance(e, exception.NoValidHost):
+                    self.message_api.create(
+                        context,
+                        defined_messages.UNABLE_TO_ALLOCATE,
+                        context.project_id,
+                        resource_type=resource_types.VOLUME,
+                        resource_uuid=request_spec['volume_id'])
                 try:
                     self._handle_failure(context, request_spec, e)
                 finally:

cinder/tests/unit/api/v3/stubs.py

@@ -0,0 +1,42 @@
+#    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.
+
+import datetime
+import iso8601
+
+from cinder.message import defined_messages
+from cinder.tests.unit import fake_constants
+
+
+FAKE_UUID = fake_constants.object_id
+
+
+def stub_message(id, **kwargs):
+    message = {
+        'id': id,
+        'event_id': defined_messages.UNABLE_TO_ALLOCATE,
+        'message_level': "ERROR",
+        'request_id': FAKE_UUID,
+        'updated_at': datetime.datetime(1900, 1, 1, 1, 1, 1,
+                                        tzinfo=iso8601.iso8601.Utc()),
+        'created_at': datetime.datetime(1900, 1, 1, 1, 1, 1,
+                                        tzinfo=iso8601.iso8601.Utc()),
+        'expires_at': datetime.datetime(1900, 1, 1, 1, 1, 1,
+                                        tzinfo=iso8601.iso8601.Utc()),
+    }
+
+    message.update(kwargs)
+    return message
+
+
+def stub_message_get(self, context, message_id):
+    return stub_message(message_id)

cinder/tests/unit/api/v3/test_messages.py

@@ -0,0 +1,140 @@
+#    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.
+
+import mock
+from oslo_config import cfg
+import webob
+
+from cinder.api import extensions
+from cinder.api.v3 import messages
+from cinder import context
+from cinder import exception
+from cinder.message import api as message_api
+from cinder.message import defined_messages
+from cinder import test
+from cinder.tests.unit.api import fakes
+from cinder.tests.unit.api.v3 import stubs
+
+CONF = cfg.CONF
+
+NS = '{http://docs.openstack.org/api/openstack-block-storage/3.0/content}'
+
+
+class MessageApiTest(test.TestCase):
+    def setUp(self):
+        super(MessageApiTest, self).setUp()
+        self.ext_mgr = extensions.ExtensionManager()
+        self.ext_mgr.extensions = {}
+        self.controller = messages.MessagesController(self.ext_mgr)
+
+        self.maxDiff = None
+        self.ctxt = context.RequestContext('admin', 'fakeproject', True)
+
+    def _expected_message_from_controller(self, id):
+        message = stubs.stub_message(id)
+        links = [
+            {'href': 'http://localhost/v3/fakeproject/messages/%s' % id,
+             'rel': 'self'},
+            {'href': 'http://localhost/fakeproject/messages/%s' % id,
+             'rel': 'bookmark'},
+        ]
+        return {
+            'message': {
+                'id': message.get('id'),
+                'user_message': defined_messages.get_message_text(
+                    message.get('event_id')),
+                'request_id': message.get('request_id'),
+                'event_id': message.get('event_id'),
+                'created_at': message.get('created_at'),
+                'message_level': message.get('message_level'),
+                'guaranteed_until': message.get('expires_at'),
+                'links': links,
+            }
+        }
+
+    def test_show(self):
+        self.stubs.Set(message_api.API, 'get', stubs.stub_message_get)
+
+        req = fakes.HTTPRequest.blank(
+            '/v3/messages/%s' % fakes.FAKE_UUID,
+            version=messages.MESSAGES_BASE_MICRO_VERSION)
+        req.environ['cinder.context'] = self.ctxt
+
+        res_dict = self.controller.show(req, fakes.FAKE_UUID)
+
+        ex = self._expected_message_from_controller(fakes.FAKE_UUID)
+        self.assertEqual(ex, res_dict)
+
+    def test_show_not_found(self):
+        self.stubs.Set(message_api.API, 'get',
+                       mock.Mock(side_effect=exception.MessageNotFound(
+                           message_id=fakes.FAKE_UUID)))
+
+        req = fakes.HTTPRequest.blank(
+            '/v3/messages/%s' % fakes.FAKE_UUID,
+            version=messages.MESSAGES_BASE_MICRO_VERSION)
+        req.environ['cinder.context'] = self.ctxt
+
+        self.assertRaises(webob.exc.HTTPNotFound, self.controller.show,
+                          req, fakes.FAKE_UUID)
+
+    def test_show_pre_microversion(self):
+        self.stubs.Set(message_api.API, 'get', stubs.stub_message_get)
+
+        req = fakes.HTTPRequest.blank('/v3/messages/%s' % fakes.FAKE_UUID,
+                                      version='3.0')
+        req.environ['cinder.context'] = self.ctxt
+
+        self.assertRaises(exception.VersionNotFoundForAPIMethod,
+                          self.controller.show, req, fakes.FAKE_UUID)
+
+    def test_delete(self):
+        self.stubs.Set(message_api.API, 'get', stubs.stub_message_get)
+        self.stubs.Set(message_api.API, 'delete', mock.Mock())
+
+        req = fakes.HTTPRequest.blank(
+            '/v3/messages/%s' % fakes.FAKE_UUID,
+            version=messages.MESSAGES_BASE_MICRO_VERSION)
+        req.environ['cinder.context'] = self.ctxt
+
+        resp = self.controller.delete(req, fakes.FAKE_UUID)
+
+        self.assertEqual(204, resp.status_int)
+        self.assertTrue(message_api.API.delete.called)
+
+    def test_delete_not_found(self):
+        self.stubs.Set(message_api.API, 'get',
+                       mock.Mock(side_effect=exception.MessageNotFound(
+                           message_id=fakes.FAKE_UUID)))
+
+        req = fakes.HTTPRequest.blank(
+            '/v3/messages/%s' % fakes.FAKE_UUID,
+            version=messages.MESSAGES_BASE_MICRO_VERSION)
+
+        self.assertRaises(webob.exc.HTTPNotFound, self.controller.delete,
+                          req, fakes.FAKE_UUID)
+
+    def test_index(self):
+        self.stubs.Set(message_api.API, 'get_all', mock.Mock(
+                       return_value=[stubs.stub_message(fakes.FAKE_UUID)]))
+        req = fakes.HTTPRequest.blank(
+            '/v3/messages/%s' % fakes.FAKE_UUID,
+            version=messages.MESSAGES_BASE_MICRO_VERSION)
+        req.environ['cinder.context'] = self.ctxt
+
+        res_dict = self.controller.index(req)
+
+        ex = self._expected_message_from_controller(fakes.FAKE_UUID)
+        expected = {
+            'messages': [ex['message']]
+        }
+        self.assertDictMatch(expected, res_dict)

cinder/tests/unit/image/test_glance.py

@@ -824,6 +824,20 @@ class TestGlanceClientVersion(test.TestCase):
 
         self.assertEqual('2', _mockglanceclient.call_args[0][0])
 
+    @mock.patch('cinder.image.glance.glanceclient.Client')
+    @mock.patch('cinder.image.glance.get_api_servers',
+                return_value=itertools.cycle([(False, 'localhost:9292')]))
+    def test_call_glance_over_quota(self, api_servers, _mockglanceclient):
+        """Test glance version set by arg to GlanceClientWrapper"""
+        glance_wrapper = glance.GlanceClientWrapper()
+        fake_client = mock.Mock()
+        fake_client.images.method = mock.Mock(
+            side_effect=glanceclient.exc.HTTPOverLimit)
+        self.mock_object(glance_wrapper, 'client', fake_client)
+        self.assertRaises(exception.ImageLimitExceeded,
+                          glance_wrapper.call, 'fake_context', 'method',
+                          version=2)
+
 
 def _create_failing_glance_client(info):
     class MyGlanceStubClient(glance_stubs.StubGlanceClient):

cinder/tests/unit/message/test_api.py

@@ -0,0 +1,94 @@
+#    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.
+import datetime
+
+import mock
+from oslo_config import cfg
+from oslo_utils import timeutils
+
+from cinder import context
+from cinder.message import api as message_api
+from cinder.message import defined_messages
+from cinder import test
+
+CONF = cfg.CONF
+
+
+class MessageApiTest(test.TestCase):
+    def setUp(self):
+        super(MessageApiTest, self).setUp()
+        self.message_api = message_api.API()
+        self.mock_object(self.message_api, 'db')
+        self.ctxt = context.RequestContext('admin', 'fakeproject', True)
+        self.ctxt.request_id = 'fakerequestid'
+
+    def test_create(self):
+        CONF.set_override('message_ttl', 300)
+        timeutils.set_time_override()
+        self.addCleanup(timeutils.clear_time_override)
+        expected_expires_at = timeutils.utcnow() + datetime.timedelta(
+            seconds=300)
+        expected_message_record = {
+            'project_id': 'fakeproject',
+            'request_id': 'fakerequestid',
+            'resource_type': 'fake_resource_type',
+            'resource_uuid': None,
+            'event_id': defined_messages.UNABLE_TO_ALLOCATE,
+            'message_level': 'ERROR',
+            'expires_at': expected_expires_at,
+        }
+        self.message_api.create(self.ctxt,
+                                defined_messages.UNABLE_TO_ALLOCATE,
+                                "fakeproject",
+                                resource_type="fake_resource_type")
+
+        self.message_api.db.message_create.assert_called_once_with(
+            self.ctxt, expected_message_record)
+
+    def test_create_swallows_exception(self):
+        self.mock_object(self.message_api.db, 'create',
+                         mock.Mock(side_effect=Exception()))
+        self.message_api.create(self.ctxt,
+                                defined_messages.UNABLE_TO_ALLOCATE,
+                                "fakeproject",
+                                "fake_resource")
+
+        self.message_api.db.message_create.assert_called_once_with(
+            self.ctxt, mock.ANY)
+
+    def test_create_does_not_allow_undefined_messages(self):
+        self.assertRaises(KeyError, self.message_api.create,
+                          self.ctxt,
+                          "FAKE_EVENT_ID",
+                          "fakeproject",
+                          "fake_resource")
+
+    def test_get(self):
+        self.message_api.get(self.ctxt, 'fake_id')
+
+        self.message_api.db.message_get.assert_called_once_with(self.ctxt,
+                                                                'fake_id')
+
+    def test_get_all(self):
+        self.message_api.get_all(self.ctxt)
+
+        self.message_api.db.message_get_all.assert_called_once_with(self.ctxt)
+
+    def test_delete(self):
+        admin_context = mock.Mock()
+        self.mock_object(self.ctxt, 'elevated',
+                         mock.Mock(return_value=admin_context))
+
+        self.message_api.delete(self.ctxt, 'fake_id')
+
+        self.message_api.db.message_destroy.assert_called_once_with(
+            admin_context, 'fake_id')

cinder/tests/unit/policy.json

@@ -107,5 +107,9 @@
     "consistencygroup:get_cgsnapshot": "",
     "consistencygroup:get_all_cgsnapshots": "",
 
-    "scheduler_extension:scheduler_stats:get_pools" : "rule:admin_api"
+    "scheduler_extension:scheduler_stats:get_pools" : "rule:admin_api",
+
+    "message:delete": "rule:admin_or_owner",
+    "message:get": "rule:admin_or_owner",
+    "message:get_all": "rule:admin_or_owner"
 }

cinder/tests/unit/scheduler/test_scheduler.py

@@ -23,6 +23,7 @@ from oslo_config import cfg
 from cinder import context
 from cinder import db
 from cinder import exception
+from cinder.message import defined_messages
 from cinder.objects import fields
 from cinder.scheduler import driver
 from cinder.scheduler import filter_scheduler
@@ -116,9 +117,11 @@ class SchedulerManagerTestCase(test.TestCase):
         _mock_update_cap.assert_called_once_with(service, host, capabilities)
 
     @mock.patch('cinder.scheduler.driver.Scheduler.schedule_create_volume')
+    @mock.patch('cinder.message.api.API.create')
     @mock.patch('cinder.db.volume_update')
     def test_create_volume_exception_puts_volume_in_error_state(
-            self, _mock_volume_update, _mock_sched_create):
+            self, _mock_volume_update, _mock_message_create,
+            _mock_sched_create):
         # Test NoValidHost exception behavior for create_volume.
         # Puts the volume in 'error' state and eats the exception.
         _mock_sched_create.side_effect = exception.NoValidHost(reason="")
@@ -136,6 +139,11 @@ class SchedulerManagerTestCase(test.TestCase):
         _mock_sched_create.assert_called_once_with(self.context, request_spec,
                                                    {})
 
+        _mock_message_create.assert_called_once_with(
+            self.context, defined_messages.UNABLE_TO_ALLOCATE,
+            self.context.project_id, resource_type='VOLUME',
+            resource_uuid=volume.id)
+
     @mock.patch('cinder.scheduler.driver.Scheduler.schedule_create_volume')
     @mock.patch('eventlet.sleep')
     def test_create_volume_no_delay(self, _mock_sleep, _mock_sched_create):

cinder/tests/unit/test_migrations.py

@@ -812,6 +812,33 @@ class MigrationsMixin(test_migrations.WalkVersionsMixin):
         fkey, = iscsi_targets.c.volume_id.foreign_keys
         self.assertIsNotNone(fkey)
 
+    def _check_074(self, engine, data):
+        """Test adding message table."""
+        self.assertTrue(engine.dialect.has_table(engine.connect(),
+                                                 "messages"))
+        messages = db_utils.get_table(engine, 'messages')
+
+        self.assertIsInstance(messages.c.created_at.type,
+                              self.TIME_TYPE)
+        self.assertIsInstance(messages.c.deleted_at.type,
+                              self.TIME_TYPE)
+        self.assertIsInstance(messages.c.deleted.type,
+                              self.BOOL_TYPE)
+        self.assertIsInstance(messages.c.message_level.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.project_id.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.id.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.request_id.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.resource_uuid.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.event_id.type,
+                              self.VARCHAR_TYPE)
+        self.assertIsInstance(messages.c.resource_type.type,
+                              self.VARCHAR_TYPE)
+
     def test_walk_versions(self):
         self.walk_versions(False, False)
 

cinder/tests/unit/test_volume.py

@@ -47,6 +47,8 @@ from cinder import db
 from cinder import exception
 from cinder.image import image_utils
 from cinder import keymgr
+from cinder.message import defined_messages
+from cinder.message import resource_types
 from cinder import objects
 from cinder.objects import fields
 import cinder.policy
@@ -130,6 +132,7 @@ class BaseVolumeTestCase(test.TestCase):
                    notification_driver=["test"])
         self.addCleanup(self._cleanup)
         self.volume = importutils.import_object(CONF.volume_manager)
+        self.volume.message_api = mock.Mock()
         self.configuration = mock.Mock(conf.Configuration)
         self.context = context.get_admin_context()
         self.context.user_id = fake.user_id
@@ -277,6 +280,7 @@ class AvailabilityZoneTestCase(BaseVolumeTestCase):
 
     def test_list_availability_zones_refetched(self):
         timeutils.set_time_override()
+        self.addCleanup(timeutils.clear_time_override)
         volume_api = cinder.volume.api.API()
         with mock.patch.object(volume_api.db,
                                'service_get_all_by_topic') as get_all:
@@ -343,7 +347,6 @@ class AvailabilityZoneTestCase(BaseVolumeTestCase):
         self.assertEqual(expected, azs)
 
 
-@ddt.ddt
 class VolumeTestCase(BaseVolumeTestCase):
 
     def setUp(self):
@@ -2879,6 +2882,13 @@ class VolumeTestCase(BaseVolumeTestCase):
                           None,
                           mountpoint,
                           'rw')
+
+        # Assert a user message was created
+        self.volume.message_api.create.assert_called_once_with(
+            self.context, defined_messages.ATTACH_READONLY_VOLUME,
+            self.context.project_id, resource_type=resource_types.VOLUME,
+            resource_uuid=volume['id'])
+
         vol = db.volume_get(context.get_admin_context(), volume_id)
         self.assertEqual('error_attaching', vol['status'])
         self.assertEqual('detached', vol['attach_status'])
@@ -4179,17 +4189,27 @@ class VolumeTestCase(BaseVolumeTestCase):
                                fake_new_volume.id)
         self.assertIsNone(volume.migration_status)
 
-    @ddt.data(False, True)
-    def test_check_volume_filters(self, filter_value):
-        """Test bootable as filter for True or False"""
+    def test_check_volume_filters_true(self):
+        """Test bootable as filter for true"""
         volume_api = cinder.volume.api.API()
-        filters = {'bootable': filter_value}
+        filters = {'bootable': 'TRUE'}
 
         # To convert filter value to True or False
         volume_api.check_volume_filters(filters)
 
-        # Confirming converted filter value against True or False
-        self.assertEqual(filter_value, filters['bootable'])
+        # Confirming converted filter value against True
+        self.assertTrue(filters['bootable'])
+
+    def test_check_volume_filters_false(self):
+        """Test bootable as filter for false"""
+        volume_api = cinder.volume.api.API()
+        filters = {'bootable': 'false'}
+
+        # To convert filter value to True or False
+        volume_api.check_volume_filters(filters)
+
+        # Confirming converted filter value against False
+        self.assertEqual(False, filters['bootable'])
 
     def test_check_volume_filters_invalid(self):
         """Test bootable as filter"""
@@ -4202,43 +4222,6 @@ class VolumeTestCase(BaseVolumeTestCase):
         # Confirming converted filter value against invalid value
         self.assertTrue(filters['bootable'])
 
-    @ddt.data('False', 'false', 'f', '0')
-    def test_check_volume_filters_strict_false(self, filter_value):
-        """Test bootable as filter for False, false, f and 0 values"""
-        volume_api = cinder.volume.api.API()
-        filters = {'bootable': filter_value}
-
-        strict = True
-        # To convert filter value to True or False
-        volume_api.check_volume_filters(filters, strict)
-
-        # Confirming converted filter value against False
-        self.assertFalse(filters['bootable'])
-
-    @ddt.data('True', 'true', 't', '1')
-    def test_check_volume_filters_strict_true(self, filter_value):
-        """Test bootable as filter for True, true, t, 1 values"""
-        volume_api = cinder.volume.api.API()
-        filters = {'bootable': filter_value}
-
-        strict = True
-        # To convert filter value to True or False
-        volume_api.check_volume_filters(filters, strict)
-
-        # Confirming converted filter value against True
-        self.assertTrue(filters['bootable'])
-
-    def test_check_volume_filters_strict_invalid(self):
-        """Test bootable as filter for invalid value."""
-        volume_api = cinder.volume.api.API()
-        filters = {'bootable': 'invalid'}
-
-        strict = True
-        # Confirming exception for invalid value in filter
-        self.assertRaises(exception.InvalidInput,
-                          volume_api.check_volume_filters,
-                          filters, strict)
-
     def test_update_volume_readonly_flag(self):
         """Test volume readonly flag can be updated at API level."""
         # create a volume and assign to host
@@ -5989,6 +5972,27 @@ class CopyVolumeToImageTestCase(BaseVolumeTestCase):
         volume = db.volume_get(self.context, self.volume_id)
         self.assertEqual('available', volume['status'])
 
+    def test_copy_volume_to_image_over_image_quota(self):
+        # creating volume testdata
+        self.volume_attrs['instance_uuid'] = None
+        volume = db.volume_create(self.context, self.volume_attrs)
+
+        with mock.patch.object(self.volume.driver,
+                               'copy_volume_to_image') as driver_copy_mock:
+            driver_copy_mock.side_effect = exception.ImageLimitExceeded
+
+            # test with image not in queued state
+            self.assertRaises(exception.ImageLimitExceeded,
+                              self.volume.copy_volume_to_image,
+                              self.context,
+                              self.volume_id,
+                              self.image_meta)
+            # Assert a user message was created
+            self.volume.message_api.create.assert_called_once_with(
+                self.context, defined_messages.IMAGE_FROM_VOLUME_OVER_QUOTA,
+                self.context.project_id, resource_type=resource_types.VOLUME,
+                resource_uuid=volume['id'])
+
     def test_copy_volume_to_image_instance_deleted(self):
         # During uploading volume to image if instance is deleted,
         # volume should be in available status.

cinder/volume/manager.py

@@ -61,6 +61,9 @@ from cinder.i18n import _, _LE, _LI, _LW
 from cinder.image import cache as image_cache
 from cinder.image import glance
 from cinder import manager
+from cinder.message import api as message_api
+from cinder.message import defined_messages
+from cinder.message import resource_types
 from cinder import objects
 from cinder.objects import fields
 from cinder import quota
@@ -282,6 +285,7 @@ class VolumeManager(manager.SchedulerDependentManager):
             host=self.host,
             is_vol_db_empty=vol_db_empty,
             active_backend_id=curr_active_backend_id)
+        self.message_api = message_api.API()
 
         if CONF.profiler.enabled and profiler is not None:
             self.driver = profiler.trace_cls("driver")(self.driver)
@@ -1000,6 +1004,10 @@ class VolumeManager(manager.SchedulerDependentManager):
             if volume_metadata.get('readonly') == 'True' and mode != 'ro':
                 self.db.volume_update(context, volume_id,
                                       {'status': 'error_attaching'})
+                self.message_api.create(
+                    context, defined_messages.ATTACH_READONLY_VOLUME,
+                    context.project_id, resource_type=resource_types.VOLUME,
+                    resource_uuid=volume_id)
                 raise exception.InvalidVolumeAttachMode(mode=mode,
                                                         volume_id=volume_id)
 
@@ -1317,6 +1325,12 @@ class VolumeManager(manager.SchedulerDependentManager):
 
             with excutils.save_and_reraise_exception():
                 payload['message'] = six.text_type(error)
+                if isinstance(error, exception.ImageLimitExceeded):
+                    self.message_api.create(
+                        context, defined_messages.IMAGE_FROM_VOLUME_OVER_QUOTA,
+                        context.project_id,
+                        resource_type=resource_types.VOLUME,
+                        resource_uuid=volume_id)
         finally:
             self.db.volume_update_status_based_on_attachment(context,
                                                              volume_id)

doc/source/devref/index.rst

@@ -34,6 +34,7 @@ Programming HowTos and Tutorials
     drivers
     gmr
     replication
+    user_messages
     migration
     api.apache
     rolling.upgrades

doc/source/devref/user_messages.rst

@@ -0,0 +1,73 @@
+User Messages
+=============
+
+User messages are a way to inform users about the state of asynchronous
+operations. One example would be notifying the user of why a volume
+provisioning request failed. These messages can be requested via the
+/messages API. All user visible messages must be defined in the permitted
+messages module in order to prevent sharing sensitive information with users.
+
+
+Example message generation::
+
+ from cinder import context
+ from cinder.message import api as message_api
+ from cinder.message import defined_messages
+ from cinder.message import resource_types
+
+ self.message_api = message_api.API()
+
+ context = context.RequestContext()
+ project_id = '6c430ede-9476-4128-8838-8d3929ced223'
+ volume_id = 'f292cc0c-54a7-4b3b-8174-d2ff82d87008'
+
+ self.message_api.create(
+     context,
+     defined_messages.UNABLE_TO_ALLOCATE,
+     project_id,
+     resource_type=resource_types.VOLUME,
+     resource_uuid=volume_id)
+
+Will produce the following::
+
+ GET /v3/6c430ede-9476-4128-8838-8d3929ced223/messages
+ {
+   "messages": [
+     {
+      "id": "5429fffa-5c76-4d68-a671-37a8e24f37cf",
+      "event_id": "000002",
+      "user_message": "No storage could be allocated for this volume request.",
+      "message_level": "ERROR",
+      "resource_type": "VOLUME",
+      "resource_uuid": "f292cc0c-54a7-4b3b-8174-d2ff82d87008",
+      "created_at": 2015-08-27T09:49:58-05:00,
+      "guaranteed_until": 2015-09-27T09:49:58-05:00,
+      "request_id": "req-936666d2-4c8f-4e41-9ac9-237b43f8b848",
+     }
+   ]
+ }
+
+
+
+The Message API Module
+----------------------
+
+.. automodule:: cinder.message.api
+    :noindex:
+    :members:
+    :undoc-members:
+
+The Resource Types Module
+-------------------------
+
+.. automodule:: cinder.message.resource_types
+    :noindex:
+
+The Permitted Messages Module
+-----------------------------
+
+.. automodule:: cinder.message.defined_messages
+    :noindex:
+    :members:
+    :undoc-members:
+    :show-inheritance:

etc/cinder/policy.json

@@ -102,5 +102,8 @@
     "consistencygroup:get_cgsnapshot": "group:nobody",
     "consistencygroup:get_all_cgsnapshots": "group:nobody",
 
-    "scheduler_extension:scheduler_stats:get_pools" : "rule:admin_api"
+    "scheduler_extension:scheduler_stats:get_pools" : "rule:admin_api",
+    "message:delete": "rule:admin_or_owner",
+    "message:get": "rule:admin_or_owner",
+    "message:get_all": "rule:admin_or_owner"
 }