Add strategy template doc

Developer should provide a detailled documentation about his strategy
algorithm to make it even easier to use by a Watcher end user.
I propose in this changeset a template for strategy documentation.
you will find also a example with basic consolidation strategy.

Change-Id: I66da1a33b87a94b508dd23ac7dce4cae6f4e068b

doc/ext/term.py

@@ -85,7 +85,12 @@ class WatcherTerm(BaseWatcherDirective):
         cls_path = self.arguments[0]
 
         try:
-            cls = importlib.import_module(cls_path)
+            try:
+                cls = importlib.import_module(cls_path)
+            except ImportError:
+                module_name, cls_name = cls_path.rsplit('.', 1)
+                mod = importlib.import_module(module_name)
+                cls = getattr(mod, cls_name)
         except Exception as exc:
             raise self.error(exc)
 
@@ -97,6 +102,72 @@ class WatcherTerm(BaseWatcherDirective):
         return node.children
 
 
+class WatcherFunc(BaseWatcherDirective):
+    """Directive to import a value returned by a func into the Watcher doc
+
+    **How to use it**
+
+    # inside your .py file
+    class Bar(object):
+
+        def foo(object):
+            return foo_string
+
+
+    # Inside your .rst file
+    .. watcher-func:: import.path.to.your.Bar.foo node_classname
+
+    node_classname is decumented here:
+    http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html
+
+    This directive will then import the value and then interpret it.
+    """
+
+    # You need to put an import path as an argument for this directive to work
+    # required_arguments = 1
+    # optional_arguments = 1
+
+    option_spec = {'format': rst.directives.unchanged}
+    has_content = True
+
+    def run(self):
+        if not self.content:
+            error = self.state_machine.reporter.error(
+                'The "%s" directive is empty; content required.' % self.name,
+                nodes.literal_block(self.block_text, self.block_text),
+                line=self.lineno)
+            return [error]
+
+        func_path = self.content[0]
+        try:
+            cls_path, func_name = func_path.rsplit('.', 1)
+            module_name, cls_name = cls_path.rsplit('.', 1)
+            mod = importlib.import_module(module_name)
+            cls = getattr(mod, cls_name)
+        except Exception as exc:
+            raise self.error(exc)
+
+        cls_obj = cls()
+        func = getattr(cls_obj, func_name)
+        textblock = func()
+        if not isinstance(textblock, str):
+            textblock = str(textblock)
+
+        self.add_textblock(textblock)
+
+        try:
+            node_class = getattr(nodes,
+                                 self.options.get('format', 'paragraph'))
+        except Exception as exc:
+            raise self.error(exc)
+
+        node = node_class()
+        node.document = self.state.document
+        self.state.nested_parse(self.result, 0, node)
+        return [node]
+
+
 def setup(app):
     app.add_directive('watcher-term', WatcherTerm)
+    app.add_directive('watcher-func', WatcherFunc)
     return {'version': version_info.version_string()}

doc/source/conf.py

@@ -78,6 +78,8 @@ exclude_patterns = [
     # them when scanning for input files.
     'man/footer.rst',
     'man/general-options.rst',
+    'strategies/strategy-template.rst',
+    'image_src/plantuml/README.rst',
 ]
 
 # If true, '()' will be appended to :func: etc. cross-reference text.

doc/source/index.rst

@@ -96,6 +96,7 @@ Introduction
   deploy/user-guide
   deploy/policy
   deploy/gmr
+  strategies/strategies
 
 Watcher Manual Pages
 ====================

doc/source/strategies/basic-server-consolidation.rst

@@ -0,0 +1,96 @@
+==================================
+Basic Offline Server Consolidation
+==================================
+
+Synopsis
+--------
+
+**display name**: ``basic``
+
+**goal**: ``server_consolidation``
+
+    .. watcher-term:: watcher.decision_engine.strategy.strategies.basic_consolidation
+
+Requirements
+------------
+
+Metrics
+*******
+
+The *basic* strategy requires the following metrics:
+
+============================ ============ ======= =======
+metric                       service name plugins comment
+============================ ============ ======= =======
+``compute.node.cpu.percent`` ceilometer_  none
+``cpu_util``                 ceilometer_  none
+============================ ============ ======= =======
+
+.. _ceilometer: http://docs.openstack.org/admin-guide/telemetry-measurements.html#openstack-compute
+
+Cluster data model
+******************
+
+Default Watcher's Compute cluster data model:
+
+    .. watcher-term:: watcher.decision_engine.model.collector.nova.NovaClusterDataModelCollector
+
+Actions
+*******
+
+Default Watcher's actions:
+
+
+    .. list-table::
+       :widths: 30 30
+       :header-rows: 1
+
+       * - action
+         - description
+       * - ``migration``
+         - .. watcher-term:: watcher.applier.actions.migration.Migrate
+       * - ``change_nova_service_state``
+         - .. watcher-term:: watcher.applier.actions.change_nova_service_state.ChangeNovaServiceState
+
+Planner
+*******
+
+Default Watcher's planner:
+
+    .. watcher-term:: watcher.decision_engine.planner.default.DefaultPlanner
+
+Configuration
+-------------
+
+Strategy parameter is:
+
+====================== ====== ============= ===================================
+parameter              type   default Value description
+====================== ====== ============= ===================================
+``migration_attempts`` Number 0             Maximum number of combinations to
+                                            be tried by the strategy while
+                                            searching for potential candidates.
+                                            To remove the limit, set it to 0
+====================== ====== ============= ===================================
+
+Efficacy Indicator
+------------------
+
+.. watcher-func::
+  :format: literal_block
+
+  watcher.decision_engine.goal.efficacy.specs.ServerConsolidation.get_global_efficacy_indicator
+
+How to use it ?
+---------------
+
+.. code-block:: shell
+
+    $ openstack optimize audittemplate create \
+      at1 server_consolidation --strategy basic
+
+    $ openstack optimize audit create -a at1 -p migration_attempts=4
+
+External Links
+--------------
+None.

doc/source/strategies/strategies.rst

@@ -0,0 +1,8 @@
+Strategies
+==========
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   ./*

doc/source/strategies/strategy-template.rst

@@ -0,0 +1,109 @@
+=============
+Strategy name
+=============
+
+Synopsis
+--------
+
+**display name**:
+
+**goal**:
+
+Add here a complete description of your strategy
+
+Requirements
+------------
+
+Metrics
+*******
+
+Write here the list of metrics required by your strategy algorithm (in the form
+ of a table). If these metrics requires specific Telemetry plugin or other
+ additional software, please explain here how to deploy them (and add link to
+ dedicated installation guide).
+
+Example:
+
+======================= ============ ======= =======
+metric                  service name plugins comment
+======================= ============ ======= =======
+compute.node.*          ceilometer_  none    one point every 60s
+vm.cpu.utilization_perc monasca_     none
+power                   ceilometer_  kwapi_  one point every 60s
+======================= ============ ======= =======
+
+
+.. _ceilometer: http://docs.openstack.org/admin-guide/telemetry-measurements.html#openstack-compute
+.. _monasca: https://github.com/openstack/monasca-agent/blob/master/docs/Libvirt.md
+.. _kwapi: https://kwapi.readthedocs.io/en/latest/index.html
+
+
+Cluster data model
+******************
+
+Default Watcher's cluster data model.
+
+or
+
+If your strategy implementation requires a new cluster data model, please
+ describe it in this section, with a link to model plugin's installation guide.
+
+Actions
+*******
+
+Default Watcher's actions.
+
+or
+
+If your strategy implementation requires new actions, add the list of Action
+ plugins here (in the form of a table) with a link to the plugin's installation
+ procedure.
+
+======== =================
+action   description
+======== =================
+action1_ This action1 ...
+action2_ This action2 ...
+======== =================
+
+.. _action1 : https://github.com/myrepo/watcher/plugins/action1
+.. _action2 : https://github.com/myrepo/watcher/plugins/action2
+
+Planner
+*******
+
+Default Watcher's planner.
+
+or
+
+If your strategy requires also a new planner to schedule built actions in time,
+ please describe it in this section, with a link to planner plugin's
+ installation guide.
+
+Configuration
+-------------
+
+If your strategy use configurable parameters, explain here how to tune them.
+
+
+Efficacy Indicator
+------------------
+
+Add here the Efficacy indicator computed by your strategy.
+
+How to use it ?
+---------------
+
+.. code-block:: shell
+
+    $ Write the command line to create an audit with your strategy.
+
+External Links
+--------------
+
+If you have written papers, blog articles .... about your strategy into Watcher,
+ or if your strategy is based from external publication(s), please add HTTP
+ links and references in this section.
+
+- `link1 <http://www.link1.papers.com>`_
+- `link2 <http://www.link2.papers.com>`_

watcher/decision_engine/goal/efficacy/specs.py

@@ -37,9 +37,9 @@ class ServerConsolidation(base.EfficacySpecification):
             indicators.InstanceMigrationsCount(),
         ]
 
-    def get_global_efficacy_indicator(self, indicators_map):
+    def get_global_efficacy_indicator(self, indicators_map=None):
         value = 0
-        if indicators_map.instance_migrations_count > 0:
+        if indicators_map and indicators_map.instance_migrations_count > 0:
             value = (float(indicators_map.released_compute_nodes_count) /
                      float(indicators_map.instance_migrations_count)) * 100
 

watcher/decision_engine/model/collector/nova.py

@@ -28,16 +28,10 @@ LOG = log.getLogger(__name__)
 
 
 class NovaClusterDataModelCollector(base.BaseClusterDataModelCollector):
-    """nova
+    """Nova cluster data model collector
 
-    *Description*
-
-    This Nova cluster data model collector creates an in-memory representation
-    of the resources exposed by the compute service.
-
-    *Spec URL*
-
-    <None>
+       The Nova cluster data model collector creates an in-memory
+       representation of the resources exposed by the compute service.
     """
 
     def __init__(self, config, osc=None):

watcher/decision_engine/strategy/strategies/basic_consolidation.py

@@ -25,6 +25,14 @@ it becomes necessary to migrate VMs among servers to lower the costs. However,
 migration of VMs introduces runtime overheads and consumes extra energy, thus
 a good server consolidation strategy should carefully plan for migration in
 order to both minimize energy consumption and comply to the various SLAs.
+
+This algorithm not only minimizes the overall number of used servers, but also
+minimizes the number of migrations.
+
+It has been developed only for tests. You must have at least 2 physical compute
+nodes to run it, so you can easilly run it on DevStack. It assumes that live
+migration is possible on your OpenStack cluster.
+
 """
 
 from oslo_log import log
@@ -39,28 +47,7 @@ LOG = log.getLogger(__name__)
 
 
 class BasicConsolidation(base.ServerConsolidationBaseStrategy):
-    """Basic offline consolidation using live migration
-
-    *Description*
-
-    This is server consolidation algorithm which not only minimizes the overall
-    number of used servers, but also minimizes the number of migrations.
-
-    *Requirements*
-
-    * You must have at least 2 physical compute nodes to run this strategy.
-
-    *Limitations*
-
-    - It has been developed only for tests.
-    - It assumes that the virtual machine and the compute node are on the same
-      private network.
-    - It assumes that live migrations are possible.
-
-    *Spec URL*
-
-    <None>
-    """
+    """Basic offline consolidation using live migration"""
 
     HOST_CPU_USAGE_METRIC_NAME = 'compute.node.cpu.percent'
     INSTANCE_CPU_USAGE_METRIC_NAME = 'cpu_util'