Move driver_dict_from_config to libvirt driver

The driver_dict_from_config helper method is only used by the
libvirt driver and is very specific to how the libvirt driver
parses the libvirt_volume_drivers list of values, so this change
moves it to the libvirt driver so that we can expand it in a
following change to add specific error handling for the libvirt
driver.

Change-Id: I2b41d9e4e72b120f70371fff1201600acaa53708

nova/tests/unit/virt/libvirt/test_driver.py

@@ -18370,3 +18370,44 @@ class LVMSnapshotTests(_BaseSnapshotTests):
     def test_qcow2(self):
         self.flags(snapshot_image_format='qcow2', group='libvirt')
         self._test_lvm_snapshot('qcow2')
+
+
+class FakeDriver(object):
+    def __init__(self, *args, **kwargs):
+        self.args = args
+        self.kwargs = kwargs
+
+
+class FakeDriver2(FakeDriver):
+    pass
+
+
+class ToDriverRegistryTestCase(test.NoDBTestCase):
+
+    def assertDriverInstance(self, inst, class_, *args, **kwargs):
+        self.assertEqual(class_, inst.__class__)
+        self.assertEqual(args, inst.args)
+        self.assertEqual(kwargs, inst.kwargs)
+
+    def test_driver_dict_from_config(self):
+        drvs = libvirt_driver.driver_dict_from_config(
+            [
+                'key1=nova.tests.unit.virt.libvirt.test_driver.FakeDriver',
+                'key2=nova.tests.unit.virt.libvirt.test_driver.FakeDriver2',
+            ], 'arg1', 'arg2', param1='value1', param2='value2'
+        )
+
+        self.assertEqual(
+            sorted(['key1', 'key2']),
+            sorted(drvs.keys())
+        )
+
+        self.assertDriverInstance(
+            drvs['key1'],
+            FakeDriver, 'arg1', 'arg2', param1='value1',
+            param2='value2')
+
+        self.assertDriverInstance(
+            drvs['key2'],
+            FakeDriver2, 'arg1', 'arg2', param1='value1',
+            param2='value2')

nova/tests/unit/virt/test_driver.py

@@ -19,47 +19,6 @@ from nova import test
 from nova.virt import driver
 
 
-class FakeDriver(object):
-    def __init__(self, *args, **kwargs):
-        self.args = args
-        self.kwargs = kwargs
-
-
-class FakeDriver2(FakeDriver):
-    pass
-
-
-class ToDriverRegistryTestCase(test.NoDBTestCase):
-
-    def assertDriverInstance(self, inst, class_, *args, **kwargs):
-        self.assertEqual(class_, inst.__class__)
-        self.assertEqual(args, inst.args)
-        self.assertEqual(kwargs, inst.kwargs)
-
-    def test_driver_dict_from_config(self):
-        drvs = driver.driver_dict_from_config(
-            [
-                'key1=nova.tests.unit.virt.test_driver.FakeDriver',
-                'key2=nova.tests.unit.virt.test_driver.FakeDriver2',
-            ], 'arg1', 'arg2', param1='value1', param2='value2'
-        )
-
-        self.assertEqual(
-            sorted(['key1', 'key2']),
-            sorted(drvs.keys())
-        )
-
-        self.assertDriverInstance(
-            drvs['key1'],
-            FakeDriver, 'arg1', 'arg2', param1='value1',
-            param2='value2')
-
-        self.assertDriverInstance(
-            drvs['key2'],
-            FakeDriver2, 'arg1', 'arg2', param1='value1',
-            param2='value2')
-
-
 class DriverMethodTestCase(test.NoDBTestCase):
 
     def setUp(self):

nova/virt/driver.py

@@ -35,17 +35,6 @@ CONF = nova.conf.CONF
 LOG = logging.getLogger(__name__)
 
 
-def driver_dict_from_config(named_driver_config, *args, **kwargs):
-    driver_registry = dict()
-
-    for driver_str in named_driver_config:
-        driver_type, _sep, driver = driver_str.partition('=')
-        driver_class = importutils.import_class(driver)
-        driver_registry[driver_type] = driver_class(*args, **kwargs)
-
-    return driver_registry
-
-
 def get_block_device_info(instance, block_device_mapping):
     """Converts block device mappings for an instance to driver format.
 

nova/virt/libvirt/driver.py

@@ -169,6 +169,17 @@ libvirt_volume_drivers = [
 ]
 
 
+def driver_dict_from_config(named_driver_config, *args, **kwargs):
+    driver_registry = dict()
+
+    for driver_str in named_driver_config:
+        driver_type, _sep, driver = driver_str.partition('=')
+        driver_class = importutils.import_class(driver)
+        driver_registry[driver_type] = driver_class(*args, **kwargs)
+
+    return driver_registry
+
+
 def patch_tpool_proxy():
     """eventlet.tpool.Proxy doesn't work with old-style class in __str__()
     or __repr__() calls. See bug #962840 for details.
@@ -352,7 +363,7 @@ class LibvirtDriver(driver.ComputeDriver):
 
         self.vif_driver = libvirt_vif.LibvirtGenericVIFDriver()
 
-        self.volume_drivers = driver.driver_dict_from_config(
+        self.volume_drivers = driver_dict_from_config(
             self._get_volume_drivers(), self._host)
 
         self._disk_cachemode = None