Tidy up - Primitive

Some Python class and packages need to be renamed
for a better compliance with the shared terminology
which provides a better understanding of Watcher
objects and components by every contributor.

This patchset is there to change
Primitive to Primitives.
Add BasePrimitive.

Partially implements: blueprint glossary-related-refactoring

Change-Id: I839bddd12b5320b338b2f207d74963afa23de522

watcher/applier/mapper/default.py

@@ -19,10 +19,12 @@
 
 
 from watcher.applier.mapper.base import BaseActionMapper
-from watcher.applier.primitive.hypervisor_state import HypervisorStateCommand
-from watcher.applier.primitive.migration import MigrateCommand
-from watcher.applier.primitive.nop import NopCommand
-from watcher.applier.primitive.power_state import PowerStateCommand
+from watcher.applier.primitives.change_nova_service_state import \
+    ChangeNovaServiceState
+from watcher.applier.primitives.migration import Migrate
+from watcher.applier.primitives.nop import Nop
+from watcher.applier.primitives.power_state import ChangePowerState
+
 from watcher.common.exception import ActionNotFound
 from watcher.decision_engine.planner.default import Primitives
 
@@ -30,18 +32,18 @@ from watcher.decision_engine.planner.default import Primitives
 class DefaultActionMapper(BaseActionMapper):
     def build_primitive_from_action(self, action):
         if action.action_type == Primitives.COLD_MIGRATE.value:
-            return MigrateCommand(action.applies_to, Primitives.COLD_MIGRATE,
-                                  action.src,
-                                  action.dst)
+            return Migrate(action.applies_to, Primitives.COLD_MIGRATE,
+                           action.src,
+                           action.dst)
         elif action.action_type == Primitives.LIVE_MIGRATE.value:
-            return MigrateCommand(action.applies_to, Primitives.COLD_MIGRATE,
-                                  action.src,
-                                  action.dst)
+            return Migrate(action.applies_to, Primitives.COLD_MIGRATE,
+                           action.src,
+                           action.dst)
         elif action.action_type == Primitives.HYPERVISOR_STATE.value:
-            return HypervisorStateCommand(action.applies_to, action.parameter)
+            return ChangeNovaServiceState(action.applies_to, action.parameter)
         elif action.action_type == Primitives.POWER_STATE.value:
-            return PowerStateCommand()
+            return ChangePowerState()
         elif action.action_type == Primitives.NOP.value:
-            return NopCommand()
+            return Nop()
         else:
             raise ActionNotFound()

watcher/applier/primitives/base.py

@@ -22,7 +22,7 @@ from watcher.applier.promise import Promise
 
 
 @six.add_metaclass(abc.ABCMeta)
-class PrimitiveCommand(object):
+class BasePrimitive(object):
     @Promise
     @abc.abstractmethod
     def execute(self):

watcher/applier/primitives/change_nova_service_state.py

@@ -20,42 +20,61 @@
 
 from oslo_config import cfg
 
-from watcher.applier.primitive.base import PrimitiveCommand
-from watcher.applier.primitive.wrapper.nova_wrapper import NovaWrapper
+from watcher.applier.primitives.base import BasePrimitive
+from watcher.applier.primitives.wrapper.nova_wrapper import NovaWrapper
 from watcher.applier.promise import Promise
-
+from watcher.common.exception import IllegalArgumentException
 from watcher.common.keystone import KeystoneClient
 from watcher.decision_engine.model.hypervisor_state import HypervisorState
 
 CONF = cfg.CONF
 
 
-class HypervisorStateCommand(PrimitiveCommand):
-    def __init__(self, host, status):
-        self.host = host
-        self.status = status
+class ChangeNovaServiceState(BasePrimitive):
+    def __init__(self, host, state):
+        """This class allows us to change the state of nova-compute service.
 
-    def nova_manage_service(self, status):
-        keystone = KeystoneClient()
-        wrapper = NovaWrapper(keystone.get_credentials(),
-                              session=keystone.get_session())
-        if status is True:
-            return wrapper.enable_service_nova_compute(self.host)
-        else:
-            return wrapper.disable_service_nova_compute(self.host)
+        :param host: the uuid of the host
+        :param state: (enabled/disabled)
+        """
+        super(BasePrimitive, self).__init__()
+        self._host = host
+        self._state = state
+
+    @property
+    def host(self):
+        return self._host
+
+    @property
+    def state(self):
+        return self._state
 
     @Promise
     def execute(self):
-        if self.status == HypervisorState.OFFLINE.value:
-            state = False
+        target_state = None
+        if self.state == HypervisorState.OFFLINE.value:
+            target_state = False
         elif self.status == HypervisorState.ONLINE.value:
-            state = True
-        return self.nova_manage_service(state)
+            target_state = True
+        return self.nova_manage_service(target_state)
 
     @Promise
     def undo(self):
-        if self.status == HypervisorState.OFFLINE.value:
-            state = True
-        elif self.status == HypervisorState.ONLINE.value:
-            state = False
-        return self.nova_manage_service(state)
+        target_state = None
+        if self.state == HypervisorState.OFFLINE.value:
+            target_state = True
+        elif self.state == HypervisorState.ONLINE.value:
+            target_state = False
+        return self.nova_manage_service(target_state)
+
+    def nova_manage_service(self, state):
+        if state is None:
+            raise IllegalArgumentException("The target state is not defined")
+
+        keystone = KeystoneClient()
+        wrapper = NovaWrapper(keystone.get_credentials(),
+                              session=keystone.get_session())
+        if state is True:
+            return wrapper.enable_service_nova_compute(self.host)
+        else:
+            return wrapper.disable_service_nova_compute(self.host)

watcher/applier/primitives/migration.py

@@ -21,8 +21,8 @@ from keystoneclient.auth.identity import v3
 from keystoneclient import session
 from oslo_config import cfg
 
-from watcher.applier.primitive.base import PrimitiveCommand
-from watcher.applier.primitive.wrapper.nova_wrapper import NovaWrapper
+from watcher.applier.primitives.base import BasePrimitive
+from watcher.applier.primitives.wrapper.nova_wrapper import NovaWrapper
 from watcher.applier.promise import Promise
 from watcher.common.keystone import KeystoneClient
 from watcher.decision_engine.planner.default import Primitives
@@ -30,11 +30,12 @@ from watcher.decision_engine.planner.default import Primitives
 CONF = cfg.CONF
 
 
-class MigrateCommand(PrimitiveCommand):
+class Migrate(BasePrimitive):
     def __init__(self, vm_uuid=None,
                  migration_type=None,
                  source_hypervisor=None,
                  destination_hypervisor=None):
+        super(BasePrimitive, self).__init__()
         self.instance_uuid = vm_uuid
         self.migration_type = migration_type
         self.source_hypervisor = source_hypervisor

watcher/applier/primitives/nop.py

@@ -19,16 +19,14 @@
 
 from oslo_log import log
 
-from watcher.applier.primitive.base import PrimitiveCommand
+from watcher.applier.primitives.base import BasePrimitive
 from watcher.applier.promise import Promise
 
 
 LOG = log.getLogger(__name__)
 
 
-class NopCommand(PrimitiveCommand):
-    def __init__(self):
-        pass
+class Nop(BasePrimitive):
 
     @Promise
     def execute(self):

watcher/applier/primitives/power_state.py

@@ -16,20 +16,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-from watcher.applier.primitive.base import PrimitiveCommand
+from watcher.applier.primitives.base import BasePrimitive
 from watcher.applier.promise import Promise
 
 
-class PowerStateCommand(PrimitiveCommand):
-    def __init__(self):
-        pass
+class ChangePowerState(BasePrimitive):
 
     @Promise
     def execute(self):
-        pass
+        raise NotImplementedError  # pragma:no cover
 
     @Promise
     def undo(self):
-        # TODO(jde): migrate VM from  target_hypervisor
-        # to current_hypervisor in model
-        return True
+        raise NotImplementedError  # pragma:no cover

watcher/metrics_engine/cluster_model_collector/manager.py

@@ -20,7 +20,7 @@
 from oslo_config import cfg
 from oslo_log import log
 
-from watcher.applier.primitive.wrapper.nova_wrapper import NovaWrapper
+from watcher.applier.primitives.wrapper.nova_wrapper import NovaWrapper
 from watcher.common.keystone import KeystoneClient
 from watcher.metrics_engine.cluster_model_collector.nova import \
     NovaClusterModelCollector

watcher/tests/applier/actions/wrapper/test_nova_wrapper.py

@@ -18,7 +18,7 @@
 #
 import mock
 import time
-from watcher.applier.primitive.wrapper.nova_wrapper import NovaWrapper
+from watcher.applier.primitives.wrapper.nova_wrapper import NovaWrapper
 from watcher.common import utils
 from watcher.tests import base