DiskAdapter Parent Class In-tree Backports

This contains backports for code changes made during in-tree driver
DiskAdapter parent class development [1].

- Forces subclasses to implement capacity methods
- Marks abstract methods/properties in the parent class
- Introduces a fake disk adapter to allow testing with abstract methods
  and properties.

[1] https://review.openstack.org/#/c/549053/

Change-Id: I1f8ebe64571c009020be7f3888167e3450d2fd4d

nova_powervm/tests/virt/powervm/disk/fake_adapter.py

@@ -0,0 +1,60 @@
+# Copyright IBM Corp. and contributors
+#
+# 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.
+
+from nova_powervm.virt.powervm.disk import driver as disk_dvr
+
+
+class FakeDiskAdapter(disk_dvr.DiskAdapter):
+    """A fake subclass of DiskAdapter.
+
+    This is done so that the abstract methods/properties can be stubbed and the
+    class can be instantiated for testing.
+    """
+    def vios_uuids(self):
+        pass
+
+    def _disk_match_func(self, disk_type, instance):
+        pass
+
+    def disconnect_disk_from_mgmt(self, vios_uuid, disk_name):
+        pass
+
+    def capacity(self):
+        pass
+
+    def capacity_used(self):
+        pass
+
+    def disconnect_disk(self, instance):
+        pass
+
+    def delete_disks(self, storage_elems):
+        pass
+
+    def create_disk_from_image(self, context, instance, image_meta):
+        pass
+
+    def connect_disk(self, instance, disk_info, stg_ftsk):
+        pass
+
+    def extend_disk(self, instance, disk_info, size):
+        pass
+
+    def check_instance_shared_storage_local(self, context, instance):
+        pass
+
+    def check_instance_shared_storage_remote(self, context, data):
+        pass

nova_powervm/tests/virt/powervm/disk/test_driver.py

@@ -1,4 +1,4 @@
-# Copyright 2015, 2017 IBM Corp.
+# Copyright IBM Corp. and contributors
 #
 # All Rights Reserved.
 #
@@ -19,8 +19,8 @@ import mock
 from nova import test
 from pypowervm import const as pvm_const
 
+from nova_powervm.tests.virt.powervm.disk import fake_adapter
 from nova_powervm.tests.virt.powervm import fixtures as fx
-from nova_powervm.virt.powervm.disk import driver as disk_dvr
 
 
 class TestDiskAdapter(test.NoDBTestCase):
@@ -36,13 +36,9 @@ class TestDiskAdapter(test.NoDBTestCase):
         self.mgmt_uuid.return_value = 'mp_uuid'
 
         # The values (adapter and host uuid) are not used in the base.
-        # Default them to None.
-        self.st_adpt = disk_dvr.DiskAdapter(None, None)
-
-    def test_capacity(self):
-        """These are arbitrary capacity numbers."""
-        self.assertEqual(2097152, self.st_adpt.capacity)
-        self.assertEqual(0, self.st_adpt.capacity_used)
+        # Default them to None. We use the fake adapter here because we can't
+        # instantiate DiskAdapter which is an abstract base class.
+        self.st_adpt = fake_adapter.FakeDiskAdapter(None, None)
 
     def test_get_info(self):
         # Ensure the base method returns empty dict

nova_powervm/virt/powervm/disk/driver.py

@@ -87,7 +87,7 @@ class DiskAdapter(object):
         self.host_uuid = host_uuid
         self.mp_uuid = mgmt.mgmt_uuid(self.adapter)
 
-    @property
+    @abc.abstractproperty
     def vios_uuids(self):
         """List the UUIDs of the Virtual I/O Servers hosting the storage."""
         raise NotImplementedError()
@@ -129,6 +129,7 @@ class DiskAdapter(object):
         return _('The configured disk driver does not support migration '
                  'or resize.')
 
+    @abc.abstractmethod
     def _disk_match_func(self, disk_type, instance):
         """Return a matching function to locate the disk for an instance.
 
@@ -214,6 +215,7 @@ class DiskAdapter(object):
         # We either didn't find the boot dev, or failed all attempts to map it.
         raise npvmex.InstanceDiskMappingFailed(instance_name=instance.name)
 
+    @abc.abstractmethod
     def disconnect_disk_from_mgmt(self, vios_uuid, disk_name):
         """Disconnect a disk from the management partition.
 
@@ -223,21 +225,15 @@ class DiskAdapter(object):
         """
         raise NotImplementedError()
 
-    @property
+    @abc.abstractproperty
     def capacity(self):
-        """Capacity of the storage in gigabytes
+        """Capacity of the storage in gigabytes."""
+        raise NotImplementedError()
 
-        Default is to make the capacity arbitrarily large
-        """
-        return 1 << 21
-
-    @property
+    @abc.abstractproperty
     def capacity_used(self):
-        """Capacity of the storage in gigabytes that is used
-
-        Default is to say none of it is used.
-        """
-        return 0
+        """Capacity of the storage in gigabytes that is used."""
+        raise NotImplementedError()
 
     @staticmethod
     def _get_disk_name(disk_type, instance, short=False):
@@ -301,6 +297,7 @@ class DiskAdapter(object):
                 disk_bytes = floor
         return disk_bytes
 
+    @abc.abstractmethod
     def disconnect_disk(self, instance, stg_ftsk=None, disk_type=None):
         """Disconnects the storage adapters from the image disk.
 
@@ -316,8 +313,9 @@ class DiskAdapter(object):
         :return: A list of all the backing storage elements that were
                  disconnected from the I/O Server and VM.
         """
-        pass
+        raise NotImplementedError()
 
+    @abc.abstractmethod
     def delete_disks(self, storage_elems):
         """Removes the disks specified by the mappings.
 
@@ -325,7 +323,7 @@ class DiskAdapter(object):
                               deleted.  Derived from the return value from
                               disconnect_disk.
         """
-        pass
+        raise NotImplementedError()
 
     def create_disk_from_image(self, context, instance, image_meta,
                                image_type=DiskType.BOOT):
@@ -370,6 +368,7 @@ class DiskAdapter(object):
         """
         pass
 
+    @abc.abstractmethod
     def connect_disk(self, instance, disk_info, stg_ftsk=None):
         """Connects the disk image to the Virtual Machine.
 
@@ -384,8 +383,9 @@ class DiskAdapter(object):
                          the FeedTask is not provided, the updates will be run
                          immediately when this method is executed.
         """
-        pass
+        raise NotImplementedError()
 
+    @abc.abstractmethod
     def extend_disk(self, instance, disk_info, size):
         """Extends the disk.
 
@@ -395,6 +395,7 @@ class DiskAdapter(object):
         """
         raise NotImplementedError()
 
+    @abc.abstractmethod
     def check_instance_shared_storage_local(self, context, instance):
         """Check if instance files located on shared storage.
 
@@ -406,6 +407,7 @@ class DiskAdapter(object):
         """
         raise NotImplementedError()
 
+    @abc.abstractmethod
     def check_instance_shared_storage_remote(self, context, data):
         """Check if instance files located on shared storage.
 

nova_powervm/virt/powervm/disk/localdisk.py

@@ -339,6 +339,25 @@ class LocalStorage(disk_dvr.DiskAdapter):
                 LOG.exception("PowerVM Error extending disk.",
                               instance=instance)
 
+    def check_instance_shared_storage_local(self, context, instance):
+        """Check if instance files located on shared storage.
+
+        This runs check on the destination host, and then calls
+        back to the source host to check the results.
+
+        :param context: security context
+        :param instance: nova.objects.instance.Instance object
+        """
+        raise NotImplementedError()
+
+    def check_instance_shared_storage_remote(self, context, data):
+        """Check if instance files located on shared storage.
+
+        :param context: security context
+        :param data: result of check_instance_shared_storage_local
+        """
+        raise NotImplementedError()
+
     def _get_vg_wrap(self):
         return pvm_stg.VG.get(self.adapter, uuid=self.vg_uuid,
                               parent_type=pvm_vios.VIOS,

nova_powervm/virt/powervm/disk/ssp.py

@@ -286,6 +286,15 @@ class SSPDiskAdapter(disk_drv.DiskAdapter):
         if stg_ftsk.name == 'ssp':
             stg_ftsk.execute()
 
+    def extend_disk(self, instance, disk_info, size):
+        """Extends the disk.
+
+        :param instance: instance to extend the disk for.
+        :param disk_info: dictionary with disk info.
+        :param size: the new size in gb.
+        """
+        raise NotImplementedError()
+
     def check_instance_shared_storage_local(self, context, instance):
         """Check if instance files located on shared storage.