Coverage for watcher/decision_engine/planner/base.py: 100%

1# -*- encoding: utf-8 -*- 

2# Copyright (c) 2015 b<>com 

3# 

4# Authors: Jean-Emile DARTOIS <jean-emile.dartois@b-com.com> 

5# 

6# Licensed under the Apache License, Version 2.0 (the "License"); 

7# you may not use this file except in compliance with the License. 

8# You may obtain a copy of the License at 

9# 

10# http://www.apache.org/licenses/LICENSE-2.0 

11# 

12# Unless required by applicable law or agreed to in writing, software 

13# distributed under the License is distributed on an "AS IS" BASIS, 

14# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 

15# implied. 

16# See the License for the specific language governing permissions and 

17# limitations under the License. 

18# 

19 

20""" 

21The :ref:`Watcher Planner <watcher_planner_definition>` is part of the 

22:ref:`Watcher Decision Engine <watcher_decision_engine_definition>`. 

23 

24This module takes the set of :ref:`Actions <action_definition>` generated by a 

25:ref:`Strategy <strategy_definition>` and builds the design of a workflow which 

26defines how-to schedule in time those different 

27:ref:`Actions <action_definition>` and for each 

28:ref:`Action <action_definition>` what are the prerequisite conditions. 

29 

30It is important to schedule :ref:`Actions <action_definition>` in time in order 

31to prevent overload of the :ref:`Cluster <cluster_definition>` while applying 

32the :ref:`Action Plan <action_plan_definition>`. For example, it is important 

33not to migrate too many instances at the same time in order to avoid a network 

34congestion which may decrease the :ref:`SLA <sla_definition>` for 

35:ref:`Customers <customer_definition>`. 

36 

37It is also important to schedule :ref:`Actions <action_definition>` in order to 

38avoid security issues such as denial of service on core OpenStack services. 

39 

40:ref:`Some default implementations are provided <watcher_planners>`, but it is 

41possible to :ref:`develop new implementations <implement_planner_plugin>` 

42which are dynamically loaded by Watcher at launch time. 

43 

44See :doc:`../architecture` for more details on this component. 

45""" 

46 

47import abc 

48 

49from watcher.common.loader import loadable 

50 

51 

52class BasePlanner(loadable.Loadable, metaclass=abc.ABCMeta): 

53 

54 @classmethod 

55 def get_config_opts(cls): 

56 """Defines the configuration options to be associated to this loadable 

57 

58 :return: A list of configuration options relative to this Loadable 

59 :rtype: list of :class:`oslo_config.cfg.Opt` instances 

60 """ 

61 return [] 

62 

63 @abc.abstractmethod 

64 def schedule(self, context, audit_uuid, solution): 

65 """The planner receives a solution to schedule 

66 

67 :param solution: A solution provided by a strategy for scheduling 

68 :type solution: :py:class:`~.BaseSolution` subclass instance 

69 :param audit_uuid: the audit uuid 

70 :type audit_uuid: str 

71 :return: Action plan with an ordered sequence of actions such that all 

72 security, dependency, and performance requirements are met. 

73 :rtype: :py:class:`watcher.objects.ActionPlan` instance 

74 """ 

75 # example: directed acyclic graph 

76 raise NotImplementedError()