Merge scoring base files

Merge scoring_engine.py and scoring_container.py to base.py

Change-Id: I5cada2c9f7832827c1bccfdea1b0a2138b18bfc9
Closes-Bug: #1617376

watcher/decision_engine/scoring/base.py

@@ -0,0 +1,126 @@
+# -*- encoding: utf-8 -*-
+# Copyright (c) 2016 Intel
+#
+# Authors: Tomasz Kaczynski <tomasz.kaczynski@intel.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
+import six
+
+from watcher.common.loader import loadable
+
+
+@six.add_metaclass(abc.ABCMeta)
+class ScoringEngine(loadable.Loadable):
+    """A base class for all the Scoring Engines.
+
+    A Scoring Engine is an instance of a data model, to which the learning
+    data was applied.
+
+    Please note that this class contains non-static and non-class methods by
+    design, so that it's easy to create multiple Scoring Engine instances
+    using a single class (possibly configured differently).
+    """
+
+    @abc.abstractmethod
+    def get_name(self):
+        """Returns the name of the Scoring Engine.
+
+        The name should be unique across all Scoring Engines.
+
+        :return: A Scoring Engine name
+        :rtype: str
+        """
+
+    @abc.abstractmethod
+    def get_description(self):
+        """Returns the description of the Scoring Engine.
+
+        The description might contain any human readable information, which
+        might be useful for Strategy developers planning to use this Scoring
+        Engine. It will be also visible in the Watcher API and CLI.
+
+        :return: A Scoring Engine description
+        :rtype: str
+        """
+
+    @abc.abstractmethod
+    def get_metainfo(self):
+        """Returns the metadata information about Scoring Engine.
+
+        The metadata might contain a machine-friendly (e.g. in JSON format)
+        information needed to use this Scoring Engine. For example, some
+        Scoring Engines require to pass the array of features in particular
+        order to be able to calculate the score value. This order can be
+        defined in metadata and used in Strategy.
+
+        :return: A Scoring Engine metadata
+        :rtype: str
+        """
+
+    @abc.abstractmethod
+    def calculate_score(self, features):
+        """Calculates a score value based on arguments passed.
+
+        Scoring Engines might be very different to each other. They might
+        solve different problems or use different algorithms or frameworks
+        internally. To enable this kind of flexibility, the method takes only
+        one argument (string) and produces the results in the same format
+        (string). The consumer of the Scoring Engine is ultimately responsible
+        for providing the right arguments and parsing the result.
+
+        :param features: Input data for Scoring Engine
+        :type features: str
+        :return: A score result
+        :rtype: str
+        """
+
+    @classmethod
+    def get_config_opts(cls):
+        """Defines the configuration options to be associated to this loadable
+
+        :return: A list of configuration options relative to this Loadable
+        :rtype: list of :class:`oslo_config.cfg.Opt` instances
+        """
+        return []
+
+
+@six.add_metaclass(abc.ABCMeta)
+class ScoringEngineContainer(loadable.Loadable):
+    """A base class for all the Scoring Engines Containers.
+
+    A Scoring Engine Container is an abstraction which allows to plugin
+    multiple Scoring Engines as a single Stevedore plugin. This enables some
+    more advanced scenarios like dynamic reloading of Scoring Engine
+    implementations without having to restart any Watcher services.
+    """
+
+    @classmethod
+    @abc.abstractmethod
+    def get_scoring_engine_list(self):
+        """Returns a list of Scoring Engine instances.
+
+        :return: A list of Scoring Engine instances
+        :rtype: :class: `~.scoring_engine.ScoringEngine`
+        """
+
+    @classmethod
+    def get_config_opts(cls):
+        """Defines the configuration options to be associated to this loadable
+
+        :return: A list of configuration options relative to this Loadable
+        :rtype: list of :class:`oslo_config.cfg.Opt` instances
+        """
+        return []