Add SAN policy setter/getter

This change adds a setter and getter for the SAN policy, controlling
the way in which new disks will be handled (brought online or not).

Validating this policy will help prevent common vm disk attachment
issues when dealing with passthrough disks.

Related-Bug: #1727257

Change-Id: I25033c15b77f494a417c9cd01d194a8bfb3cfe13

os_win/constants.py

@@ -233,3 +233,9 @@ SUPPORTED_SCSI_UID_FORMATS = [
     SCSI_UID_VENDOR_ID,
     SCSI_UID_VENDOR_SPECIFIC
 ]
+
+DISK_POLICY_UNKNOWN = 0
+DISK_POLICY_ONLINE_ALL = 1
+DISK_POLICY_OFFLINE_SHARED = 2
+DISK_POLICY_OFFLINE_ALL = 3
+DISK_POLICY_OFFLINE_INTERNAL = 4

os_win/tests/unit/utils/storage/test_diskutils.py

@@ -369,3 +369,18 @@ class DiskUtilsTestCase(test_base.OsWinBaseTestCase):
         result = self._diskutils._select_supported_scsi_identifiers(
             identifiers)
         self.assertEqual(expected_identifiers, result)
+
+    def test_get_new_disk_policy(self):
+        mock_setting_obj = mock.Mock()
+        setting_cls = self._diskutils._conn_storage.MSFT_StorageSetting
+        setting_cls.Get.return_value = (0, mock_setting_obj)
+
+        policy = self._diskutils.get_new_disk_policy()
+        self.assertEqual(mock_setting_obj.NewDiskPolicy, policy)
+
+    def test_set_new_disk_policy(self):
+        self._diskutils.set_new_disk_policy(mock.sentinel.policy)
+
+        setting_cls = self._diskutils._conn_storage.MSFT_StorageSetting
+        setting_cls.Set.assert_called_once_with(
+            NewDiskPolicy=mock.sentinel.policy)

os_win/utils/storage/diskutils.py

@@ -301,3 +301,18 @@ class DiskUtils(baseutils.BaseUtils):
                     selected_identifiers.append(identifier)
 
         return selected_identifiers
+
+    def get_new_disk_policy(self):
+        # This policy is also known as the 'SAN policy', describing
+        # how new disks will be handled.
+        storsetting = self._conn_storage.MSFT_StorageSetting.Get()[1]
+        return storsetting.NewDiskPolicy
+
+    def set_new_disk_policy(self, policy):
+        """Sets the new disk policy, also known as SAN policy.
+
+        :param policy: an integer value, one of the DISK_POLICY_*
+                       values defined in os_win.constants.
+        """
+        self._conn_storage.MSFT_StorageSetting.Set(
+            NewDiskPolicy=policy)