volume: Add 'volume message *' commands

This patch implements the necessary commands to utilize the Messages API
introduced in Cinder API version 3.3. Version 3.5 built upon this by
implementing pagination support for these commands which is present in
this patch as well.

  volume message get
  volume message list
  volume message delete

Change-Id: I64aa0b4a8d4468baa8c63e5e30ee31de68df999d

Author: stephenfin

doc/source/cli/command-objects/volume-message.rst

@@ -0,0 +1,8 @@
+==============
+volume message
+==============
+
+Block Storage v3
+
+.. autoprogram-cliff:: openstack.volume.v3
+   :command: volume message *

doc/source/cli/commands.rst

@@ -160,6 +160,7 @@ referring to both Compute and Volume quotas.
 * ``volume backup record``: (**Volume**) volume record that can be imported or exported
 * ``volume backend``: (**Volume**) volume backend storage
 * ``volume host``: (**Volume**) the physical computer for volumes
+* ``volume message``: (**Volume**) volume API internal messages detailing volume failure messages
 * ``volume qos``: (**Volume**) quality-of-service (QoS) specification for volumes
 * ``volume snapshot``: (**Volume**) a point-in-time copy of a volume
 * ``volume type``: (**Volume**) deployment-specific types of volumes available

doc/source/cli/data/cinder.csv

@@ -72,9 +72,9 @@ list,volume list,Lists all volumes.
 list-filters,,List enabled filters. (Supported by API versions 3.33 - 3.latest)
 manage,volume create --remote-source k=v,Manage an existing volume.
 manageable-list,,Lists all manageable volumes. (Supported by API versions 3.8 - 3.latest)
-message-delete,,Removes one or more messages. (Supported by API versions 3.3 - 3.latest)
-message-list,,Lists all messages. (Supported by API versions 3.3 - 3.latest)
-message-show,,Shows message details. (Supported by API versions 3.3 - 3.latest)
+message-delete,volume message delete,Removes one or more messages. (Supported by API versions 3.3 - 3.latest)
+message-list,volume message list,Lists all messages. (Supported by API versions 3.3 - 3.latest)
+message-show,volume message show,Shows message details. (Supported by API versions 3.3 - 3.latest)
 metadata,volume set --property k=v / volume unset --property k,Sets or deletes volume metadata.
 metadata-show,volume show,Shows volume metadata.
 metadata-update-all,volume set --property k=v,Updates volume metadata.

openstackclient/tests/unit/volume/v3/fakes.py

@@ -32,6 +32,8 @@ def __init__(self, **kwargs):
 
         self.attachments = mock.Mock()
         self.attachments.resource_class = fakes.FakeResource(None, {})
+        self.messages = mock.Mock()
+        self.messages.resource_class = fakes.FakeResource(None, {})
         self.volumes = mock.Mock()
         self.volumes.resource_class = fakes.FakeResource(None, {})
 
@@ -59,6 +61,72 @@ def setUp(self):
 FakeVolume = volume_v2_fakes.FakeVolume
 
 
+class FakeVolumeMessage:
+    """Fake one or more volume messages."""
+
+    @staticmethod
+    def create_one_volume_message(attrs=None):
+        """Create a fake message.
+
+        :param attrs: A dictionary with all attributes of message
+        :return: A FakeResource object with id, name, status, etc.
+        """
+        attrs = attrs or {}
+
+        # Set default attribute
+        message_info = {
+            'created_at': '2016-02-11T11:17:37.000000',
+            'event_id': f'VOLUME_{random.randint(1, 999999):06d}',
+            'guaranteed_until': '2016-02-11T11:17:37.000000',
+            'id': uuid.uuid4().hex,
+            'message_level': 'ERROR',
+            'request_id': f'req-{uuid.uuid4().hex}',
+            'resource_type': 'VOLUME',
+            'resource_uuid': uuid.uuid4().hex,
+            'user_message': f'message-{uuid.uuid4().hex}',
+        }
+
+        # Overwrite default attributes if there are some attributes set
+        message_info.update(attrs)
+
+        message = fakes.FakeResource(
+            None,
+            message_info,
+            loaded=True)
+        return message
+
+    @staticmethod
+    def create_volume_messages(attrs=None, count=2):
+        """Create multiple fake messages.
+
+        :param attrs: A dictionary with all attributes of message
+        :param count: The number of messages to be faked
+        :return: A list of FakeResource objects
+        """
+        messages = []
+        for n in range(0, count):
+            messages.append(FakeVolumeMessage.create_one_volume_message(attrs))
+
+        return messages
+
+    @staticmethod
+    def get_volume_messages(messages=None, count=2):
+        """Get an iterable MagicMock object with a list of faked messages.
+
+        If messages list is provided, then initialize the Mock object with the
+        list. Otherwise create one.
+
+        :param messages: A list of FakeResource objects faking messages
+        :param count: The number of messages to be faked
+        :return An iterable Mock object with side_effect set to a list of faked
+            messages
+        """
+        if messages is None:
+            messages = FakeVolumeMessage.create_messages(count)
+
+        return mock.Mock(side_effect=messages)
+
+
 class FakeVolumeAttachment:
     """Fake one or more volume attachments."""