Tidy up - Watcher Decision Engine package

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 the code structure by adding the folder
"strategies" and "loading".

Partially implements: blueprint glossary-related-refactoring

Change-Id: I56fb24ee6762b3186eccde5983233e17bb227cc1

watcher/decision_engine/actions/base.py

@@ -17,9 +17,9 @@
 # limitations under the License.
 #
 import abc
-import six
 
-from watcher.decision_engine.strategy.level import StrategyLevel
+import six
+from watcher.decision_engine.strategy.common.level import StrategyLevel
 
 
 @six.add_metaclass(abc.ABCMeta)

watcher/decision_engine/strategy/context/default.py

@@ -17,7 +17,7 @@ from oslo_log import log
 
 from watcher.decision_engine.planner.default import DefaultPlanner
 from watcher.decision_engine.strategy.context.base import BaseStrategyContext
-from watcher.decision_engine.strategy.selector.default import StrategySelector
+from watcher.decision_engine.strategy.selection.default import StrategySelector
 
 LOG = log.getLogger(__name__)
 

watcher/decision_engine/strategy/loading/base.py

@@ -0,0 +1,43 @@
+# -*- encoding: utf-8 -*-
+# Copyright (c) 2015 b<>com
+#
+# Authors: Jean-Emile DARTOIS <jean-emile.dartois@b-com.com>
+#
+# 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.
+#
+import abc
+from oslo_log import log
+import six
+
+LOG = log.getLogger(__name__)
+
+
+@six.add_metaclass(abc.ABCMeta)
+class BaseStrategyLoader(object):
+    @abc.abstractmethod
+    def load_available_strategies(self):
+        raise NotImplementedError()  # pragma:no cover
+
+    def load(self, strategy_to_load=None):
+        strategy_selected = None
+        try:
+            available_strategies = self.load_available_strategies()
+            strategy_cls = available_strategies.get(
+                strategy_to_load, self.default_strategy_cls
+            )
+            strategy_selected = strategy_cls()
+        except Exception as exc:
+            LOG.exception(exc)
+
+        return strategy_selected

watcher/decision_engine/strategy/loading/default.py

@@ -21,32 +21,21 @@ from __future__ import unicode_literals
 
 from oslo_log import log
 from stevedore import ExtensionManager
-from watcher.decision_engine.strategy.basic_consolidation import \
+
+from watcher.decision_engine.strategy.loading.base import BaseStrategyLoader
+from watcher.decision_engine.strategy.strategies.basic_consolidation import \
     BasicConsolidation
 
 LOG = log.getLogger(__name__)
 
 
-class StrategyLoader(object):
+class DefaultStrategyLoader(BaseStrategyLoader):
 
     default_strategy_cls = BasicConsolidation
 
-    def load_strategies(self):
+    def load_available_strategies(self):
         extension_manager = ExtensionManager(
             namespace='watcher_strategies',
             invoke_on_load=True,
         )
         return {ext.name: ext.plugin for ext in extension_manager.extensions}
-
-    def load(self, model):
-        strategy = None
-        try:
-            available_strategies = self.load_strategies()
-            strategy_cls = available_strategies.get(
-                model, self.default_strategy_cls
-            )
-            strategy = strategy_cls()
-        except Exception as exc:
-            LOG.exception(exc)
-
-        return strategy

watcher/decision_engine/strategy/selection/default.py

@@ -16,9 +16,12 @@
 
 from oslo_config import cfg
 from oslo_log import log
+
 from watcher.common.exception import WatcherException
-from watcher.decision_engine.strategy.loader import StrategyLoader
-from watcher.decision_engine.strategy.selector.base import BaseSelector
+from watcher.decision_engine.strategy.loading.default import \
+    DefaultStrategyLoader
+from watcher.decision_engine.strategy.selection.base import BaseSelector
+
 LOG = log.getLogger(__name__)
 CONF = cfg.CONF
 
@@ -41,7 +44,7 @@ CONF.register_opts(WATCHER_GOALS_OPTS, goals_opt_group)
 class StrategySelector(BaseSelector):
 
     def __init__(self):
-        self.strategy_loader = StrategyLoader()
+        self.strategy_loader = DefaultStrategyLoader()
 
     def define_from_goal(self, goal_name):
         strategy_to_load = None

watcher/decision_engine/strategy/strategies/base.py

@@ -16,12 +16,12 @@
 
 import abc
 from oslo_log import log
-
 import six
-from watcher.decision_engine.solution.default import DefaultSolution
-from watcher.decision_engine.strategy.level import StrategyLevel
 
 
+from watcher.decision_engine.solution.default import DefaultSolution
+from watcher.decision_engine.strategy.common.level import StrategyLevel
+
 LOG = log.getLogger(__name__)
 
 

watcher/decision_engine/strategy/strategies/basic_consolidation.py

@@ -28,8 +28,8 @@ from watcher.decision_engine.model.hypervisor_state import HypervisorState
 from watcher.decision_engine.model.power_state import PowerState
 from watcher.decision_engine.model.resource import ResourceType
 from watcher.decision_engine.model.vm_state import VMState
-from watcher.decision_engine.strategy.base import BaseStrategy
-from watcher.decision_engine.strategy.level import StrategyLevel
+from watcher.decision_engine.strategy.common.level import StrategyLevel
+from watcher.decision_engine.strategy.strategies.base import BaseStrategy
 from watcher.metrics_engine.cluster_history.ceilometer import \
     CeilometerClusterHistory
 
@@ -53,12 +53,12 @@ class BasicConsolidation(BaseStrategy):
     and often tend to migrate from one physical machine to another.
     Hence, the traditional and offline heuristics such as bin packing
     are not applicable for the placement VM in cloud computing.
-    So, the decision Engine optimizer provide placement strategy considering
+    So, the decision Engine optimizer provides placement strategy considering
     not only the performance effects but also the workload characteristics of
     VMs and others metrics like the power consumption and
     the tenants constraints (SLAs).
 
-    The watcher optimizer use an online VM placement technique
+    The watcher optimizer uses an online VM placement technique
     based on machine learning and meta-heuristics that must handle :
     - multi-objectives
     - Contradictory objectives
@@ -121,9 +121,9 @@ class BasicConsolidation(BaseStrategy):
                         vm_to_mig):
         '''check if the migration is possible
 
-        :param model: current state of the cluster
-        :param src_hypervisor: the current of the virtual machine
-        :param dest_hypervisor:the destination of the virtual machine
+        :param model: the current state of the cluster
+        :param src_hypervisor: the current node of the virtual machine
+        :param dest_hypervisor: the destination of the virtual machine
         :param vm_to_mig: the virtual machine
         :return: True if the there is enough place otherwise false
         '''
@@ -167,7 +167,7 @@ class BasicConsolidation(BaseStrategy):
         """Check threshold
 
         check the threshold value defined by the ratio of
-        aggregated CPU capacity of VMS on one node to CPU capacity
+        aggregated CPU capacity of VMs on one node to CPU capacity
         of this node must not exceed the threshold value.
         :param dest_hypervisor:
         :param total_cores
@@ -213,7 +213,7 @@ class BasicConsolidation(BaseStrategy):
 
     def calculate_weight(self, model, element, total_cores_used,
                          total_disk_used, total_memory_used):
-        """Calculate weight of every
+        """Calculate weight of every resource
 
         :param model:
         :param element:
@@ -248,7 +248,7 @@ class BasicConsolidation(BaseStrategy):
         return (score_cores + score_disk + score_memory) / 3
 
     def calculate_score_node(self, hypervisor, model):
-        """calculate the score that reprensent the utilization level
+        """calculate the score that represent the utilization level
 
             :param hypervisor:
             :param model:
@@ -331,7 +331,7 @@ class BasicConsolidation(BaseStrategy):
                                  model)))
 
     def execute(self, orign_model):
-        LOG.debug("initialize Sercon Consolidation")
+        LOG.debug("Initialize Sercon Consolidation")
 
         if orign_model is None:
             raise ClusterStateNotDefined()
@@ -411,7 +411,7 @@ class BasicConsolidation(BaseStrategy):
                     vm_score.append(
                         (vm_id, self.calculate_score_vm(vm, current_model)))
 
-            ''' sort VM's by Score '''
+            ''' sort VMs by Score '''
             v = sorted(vm_score, reverse=True, key=lambda x: (x[1]))
             LOG.debug("VM(s) BFD {0}".format(v))
 

watcher/decision_engine/strategy/strategies/dummy_strategy.py

@@ -17,9 +17,9 @@
 # limitations under the License.
 #
 from oslo_log import log
+from watcher.decision_engine.strategy.strategies.base import BaseStrategy
 
 from watcher.decision_engine.actions.nop import Nop
-from watcher.decision_engine.strategy.base import BaseStrategy
 
 LOG = log.getLogger(__name__)