Separate StackWatch out into it's own module

In the interest in small modules that have a matching unit test file.

Part of blueprint decouple-nested
Change-Id: Ia40310007113b1111883a20db99cb7f754ae43bf

4 files changed, 222 insertions, 160 deletions

diff --git a/heat/engine/service.py b/heat/engine/service.py
index 5c0781444..33b582558 100644
--- a/heat/engine/service.py
+++ b/heat/engine/service.py
@@ -20,7 +20,6 @@ import eventlet
 from oslo.config import cfg
 from oslo import messaging
 from oslo.serialization import jsonutils
-from oslo.utils import timeutils
 from osprofiler import profiler
 import requests
 import six
@@ -44,6 +43,7 @@ from heat.engine import event as evt
 from heat.engine import parameter_groups
 from heat.engine import properties
 from heat.engine import resources
+from heat.engine import service_stack_watch
 from heat.engine import stack as parser
 from heat.engine import stack_lock
 from heat.engine import template as templatem
@@ -216,88 +216,6 @@ class ThreadGroupManager(object):
             event.send(message)
 
 
-class StackWatch(object):
-    def __init__(self, thread_group_mgr):
-        self.thread_group_mgr = thread_group_mgr
-
-    def start_watch_task(self, stack_id, cnxt):
-
-        def stack_has_a_watchrule(sid):
-            wrs = db_api.watch_rule_get_all_by_stack(cnxt, sid)
-
-            now = timeutils.utcnow()
-            start_watch_thread = False
-            for wr in wrs:
-                # reset the last_evaluated so we don't fire off alarms when
-                # the engine has not been running.
-                db_api.watch_rule_update(cnxt, wr.id, {'last_evaluated': now})
-
-                if wr.state != rpc_api.WATCH_STATE_CEILOMETER_CONTROLLED:
-                    start_watch_thread = True
-
-            children = db_api.stack_get_all_by_owner_id(cnxt, sid)
-            for child in children:
-                if stack_has_a_watchrule(child.id):
-                    start_watch_thread = True
-
-            return start_watch_thread
-
-        if stack_has_a_watchrule(stack_id):
-            self.thread_group_mgr.add_timer(
-                stack_id,
-                self.periodic_watcher_task,
-                sid=stack_id)
-
-    def check_stack_watches(self, sid):
-        # Retrieve the stored credentials & create context
-        # Require tenant_safe=False to the stack_get to defeat tenant
-        # scoping otherwise we fail to retrieve the stack
-        LOG.debug("Periodic watcher task for stack %s" % sid)
-        admin_context = context.get_admin_context()
-        db_stack = db_api.stack_get(admin_context, sid, tenant_safe=False,
-                                    eager_load=True)
-        if not db_stack:
-            LOG.error(_LE("Unable to retrieve stack %s for periodic task"),
-                      sid)
-            return
-        stack = parser.Stack.load(admin_context, stack=db_stack,
-                                  use_stored_context=True)
-
-        # recurse into any nested stacks.
-        children = db_api.stack_get_all_by_owner_id(admin_context, sid)
-        for child in children:
-            self.check_stack_watches(child.id)
-
-        # Get all watchrules for this stack and evaluate them
-        try:
-            wrs = db_api.watch_rule_get_all_by_stack(admin_context, sid)
-        except Exception as ex:
-            LOG.warn(_LW('periodic_task db error watch rule removed? %(ex)s'),
-                     ex)
-            return
-
-        def run_alarm_action(stack, actions, details):
-            for action in actions:
-                action(details=details)
-            for res in stack.itervalues():
-                res.metadata_update()
-
-        for wr in wrs:
-            rule = watchrule.WatchRule.load(stack.context, watch=wr)
-            actions = rule.evaluate()
-            if actions:
-                self.thread_group_mgr.start(sid, run_alarm_action, stack,
-                                            actions, rule.get_details())
-
-    def periodic_watcher_task(self, sid):
-        """
-        Periodic task, created for each stack, triggers watch-rule
-        evaluation for all rules defined for the stack
-        sid = stack ID
-        """
-        self.check_stack_watches(sid)
-
-
 @profiler.trace_cls("rpc")
 class EngineListener(service.Service):
     '''
@@ -384,7 +302,8 @@ class EngineService(service.Service):
         # so we need to create a ThreadGroupManager here for the periodic tasks
         if self.thread_group_mgr is None:
             self.thread_group_mgr = ThreadGroupManager()
-        self.stack_watch = StackWatch(self.thread_group_mgr)
+        self.stack_watch = service_stack_watch.StackWatch(
+            self.thread_group_mgr)
 
         # Create a periodic_watcher_task per-stack
         admin_context = context.get_admin_context()
diff --git a/heat/engine/service_stack_watch.py b/heat/engine/service_stack_watch.py
new file mode 100644
index 000000000..ece76b957
--- /dev/null
+++ b/heat/engine/service_stack_watch.py
@@ -0,0 +1,107 @@
+#
+#    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.
+
+from oslo.utils import timeutils
+
+from heat.common import context
+from heat.common.i18n import _LE
+from heat.common.i18n import _LW
+from heat.db import api as db_api
+from heat.engine import stack
+from heat.engine import watchrule
+from heat.openstack.common import log as logging
+from heat.rpc import api as rpc_api
+
+LOG = logging.getLogger(__name__)
+
+
+class StackWatch(object):
+    def __init__(self, thread_group_mgr):
+        self.thread_group_mgr = thread_group_mgr
+
+    def start_watch_task(self, stack_id, cnxt):
+
+        def stack_has_a_watchrule(sid):
+            wrs = db_api.watch_rule_get_all_by_stack(cnxt, sid)
+
+            now = timeutils.utcnow()
+            start_watch_thread = False
+            for wr in wrs:
+                # reset the last_evaluated so we don't fire off alarms when
+                # the engine has not been running.
+                db_api.watch_rule_update(cnxt, wr.id, {'last_evaluated': now})
+
+                if wr.state != rpc_api.WATCH_STATE_CEILOMETER_CONTROLLED:
+                    start_watch_thread = True
+
+            children = db_api.stack_get_all_by_owner_id(cnxt, sid)
+            for child in children:
+                if stack_has_a_watchrule(child.id):
+                    start_watch_thread = True
+
+            return start_watch_thread
+
+        if stack_has_a_watchrule(stack_id):
+            self.thread_group_mgr.add_timer(
+                stack_id,
+                self.periodic_watcher_task,
+                sid=stack_id)
+
+    def check_stack_watches(self, sid):
+        # Retrieve the stored credentials & create context
+        # Require tenant_safe=False to the stack_get to defeat tenant
+        # scoping otherwise we fail to retrieve the stack
+        LOG.debug("Periodic watcher task for stack %s" % sid)
+        admin_context = context.get_admin_context()
+        db_stack = db_api.stack_get(admin_context, sid, tenant_safe=False,
+                                    eager_load=True)
+        if not db_stack:
+            LOG.error(_LE("Unable to retrieve stack %s for periodic task"),
+                      sid)
+            return
+        stk = stack.Stack.load(admin_context, stack=db_stack,
+                               use_stored_context=True)
+
+        # recurse into any nested stacks.
+        children = db_api.stack_get_all_by_owner_id(admin_context, sid)
+        for child in children:
+            self.check_stack_watches(child.id)
+
+        # Get all watchrules for this stack and evaluate them
+        try:
+            wrs = db_api.watch_rule_get_all_by_stack(admin_context, sid)
+        except Exception as ex:
+            LOG.warn(_LW('periodic_task db error watch rule removed? %(ex)s'),
+                     ex)
+            return
+
+        def run_alarm_action(stk, actions, details):
+            for action in actions:
+                action(details=details)
+            for res in stk.itervalues():
+                res.metadata_update()
+
+        for wr in wrs:
+            rule = watchrule.WatchRule.load(stk.context, watch=wr)
+            actions = rule.evaluate()
+            if actions:
+                self.thread_group_mgr.start(sid, run_alarm_action, stk,
+                                            actions, rule.get_details())
+
+    def periodic_watcher_task(self, sid):
+        """
+        Periodic task, created for each stack, triggers watch-rule
+        evaluation for all rules defined for the stack
+        sid = stack ID
+        """
+        self.check_stack_watches(sid)
diff --git a/heat/tests/test_engine_service.py b/heat/tests/test_engine_service.py
index c0db2c32c..143db8082 100644
--- a/heat/tests/test_engine_service.py
+++ b/heat/tests/test_engine_service.py
@@ -31,7 +31,6 @@ import six
 from heat.common import exception
 from heat.common import identifier
 from heat.common import template_format
-from heat.common import urlfetch
 from heat.db import api as db_api
 from heat.engine.clients.os import glance
 from heat.engine.clients.os import keystone
@@ -42,6 +41,7 @@ from heat.engine import properties
 from heat.engine import resource as res
 from heat.engine.resources import instance as instances
 from heat.engine import service
+from heat.engine import service_stack_watch
 from heat.engine import stack as parser
 from heat.engine import stack_lock
 from heat.engine import template as templatem
@@ -106,38 +106,6 @@ wp_template_no_default = '''
 }
 '''
 
-nested_alarm_template = '''
-HeatTemplateFormatVersion: '2012-12-12'
-Resources:
-  the_nested:
-    Type: AWS::CloudFormation::Stack
-    Properties:
-      TemplateURL: https://server.test/alarm.template
-'''
-
-alarm_template = '''
-{
-  "AWSTemplateFormatVersion" : "2010-09-09",
-  "Description" : "alarming",
-  "Resources" : {
-    "service_alarm": {
-      "Type": "AWS::CloudWatch::Alarm",
-      "Properties": {
-        "EvaluationPeriods": "1",
-        "AlarmActions": [],
-        "AlarmDescription": "do the thing",
-        "Namespace": "dev/null",
-        "Period": "300",
-        "ComparisonOperator": "GreaterThanThreshold",
-        "Statistic": "SampleCount",
-        "Threshold": "2",
-        "MetricName": "ServiceFailure"
-      }
-    }
-  }
-}
-'''
-
 policy_template = '''
 {
   "AWSTemplateFormatVersion" : "2010-09-09",
@@ -1633,7 +1601,7 @@ class StackServiceTest(common.HeatTestCase):
         res._register_class('ResourceWithPropsType',
                             generic_rsrc.ResourceWithProps)
 
-    @mock.patch.object(service.StackWatch, 'start_watch_task')
+    @mock.patch.object(service_stack_watch.StackWatch, 'start_watch_task')
     @mock.patch.object(service.db_api, 'stack_get_all')
     @mock.patch.object(service.service.Service, 'start')
     def test_start_watches_all_stacks(self, mock_super_start, mock_get_all,
@@ -2633,48 +2601,6 @@ class StackServiceTest(common.HeatTestCase):
 
         self.m.VerifyAll()
 
-    @stack_context('periodic_watch_task_not_created')
-    def test_periodic_watch_task_not_created(self):
-        self.eng.thread_group_mgr.groups[self.stack.id] = DummyThreadGroup()
-        self.eng.stack_watch.start_watch_task(self.stack.id, self.ctx)
-        self.assertEqual(
-            [], self.eng.thread_group_mgr.groups[self.stack.id].threads)
-
-    def test_periodic_watch_task_created(self):
-        stack = get_stack('period_watch_task_created',
-                          utils.dummy_context(),
-                          alarm_template)
-        self.stack = stack
-        self.m.ReplayAll()
-        stack.store()
-        stack.create()
-        self.eng.thread_group_mgr.groups[stack.id] = DummyThreadGroup()
-        self.eng.stack_watch.start_watch_task(stack.id, self.ctx)
-        expected = [self.eng.stack_watch.periodic_watcher_task]
-        observed = self.eng.thread_group_mgr.groups[stack.id].threads
-        self.assertEqual(expected, observed)
-        self.stack.delete()
-
-    def test_periodic_watch_task_created_nested(self):
-        self.m.StubOutWithMock(urlfetch, 'get')
-        urlfetch.get('https://server.test/alarm.template').MultipleTimes().\
-            AndReturn(alarm_template)
-        self.m.ReplayAll()
-
-        stack = get_stack('period_watch_task_created_nested',
-                          utils.dummy_context(),
-                          nested_alarm_template)
-        setup_keystone_mocks(self.m, stack)
-        self.stack = stack
-        self.m.ReplayAll()
-        stack.store()
-        stack.create()
-        self.eng.thread_group_mgr.groups[stack.id] = DummyThreadGroup()
-        self.eng.stack_watch.start_watch_task(stack.id, self.ctx)
-        self.assertEqual([self.eng.stack_watch.periodic_watcher_task],
-                         self.eng.thread_group_mgr.groups[stack.id].threads)
-        self.stack.delete()
-
     @stack_context('service_show_watch_test_stack', False)
     def test_show_watch(self):
         # Insert two dummy watch rules into the DB
diff --git a/heat/tests/test_engine_service_stack_watch.py b/heat/tests/test_engine_service_stack_watch.py
new file mode 100644
index 000000000..739e12b3f
--- /dev/null
+++ b/heat/tests/test_engine_service_stack_watch.py
@@ -0,0 +1,110 @@
+#
+#    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 mock
+
+from heat.engine import service_stack_watch
+from heat.rpc import api as rpc_api
+from heat.tests import common
+from heat.tests import utils
+
+
+class StackServiceWatcherTest(common.HeatTestCase):
+
+    def setUp(self):
+        super(StackServiceWatcherTest, self).setUp()
+
+        self.ctx = utils.dummy_context(tenant_id='stack_service_test_tenant')
+        self.patch('heat.engine.service.warnings')
+
+    @mock.patch.object(service_stack_watch.db_api, 'stack_get_all_by_owner_id')
+    @mock.patch.object(service_stack_watch.db_api,
+                       'watch_rule_get_all_by_stack')
+    @mock.patch.object(service_stack_watch.db_api, 'watch_rule_update')
+    def test_periodic_watch_task_not_created(self, watch_rule_update,
+                                             watch_rule_get_all_by_stack,
+                                             stack_get_all_by_owner_id):
+        """If there is no cloud watch lite alarm, then don't create
+        a periodic task for it.
+        """
+        stack_id = 83
+        watch_rule_get_all_by_stack.return_value = []
+        stack_get_all_by_owner_id.return_value = []
+        tg = mock.Mock()
+        sw = service_stack_watch.StackWatch(tg)
+        sw.start_watch_task(stack_id, self.ctx)
+
+        # assert that add_timer is NOT called.
+        self.assertEqual([], tg.add_timer.call_args_list)
+
+    @mock.patch.object(service_stack_watch.db_api, 'stack_get_all_by_owner_id')
+    @mock.patch.object(service_stack_watch.db_api,
+                       'watch_rule_get_all_by_stack')
+    @mock.patch.object(service_stack_watch.db_api, 'watch_rule_update')
+    def test_periodic_watch_task_created(self, watch_rule_update,
+                                         watch_rule_get_all_by_stack,
+                                         stack_get_all_by_owner_id):
+        """If there is no cloud watch lite alarm, then DO create
+        a periodic task for it.
+        """
+        stack_id = 86
+        wr1 = mock.Mock()
+        wr1.id = 4
+        wr1.state = rpc_api.WATCH_STATE_NODATA
+
+        watch_rule_get_all_by_stack.return_value = [wr1]
+        stack_get_all_by_owner_id.return_value = []
+        tg = mock.Mock()
+        sw = service_stack_watch.StackWatch(tg)
+        sw.start_watch_task(stack_id, self.ctx)
+
+        # assert that add_timer IS called.
+        self.assertEqual([mock.call(stack_id, sw.periodic_watcher_task,
+                                    sid=stack_id)],
+                         tg.add_timer.call_args_list)
+
+    @mock.patch.object(service_stack_watch.db_api, 'stack_get_all_by_owner_id')
+    @mock.patch.object(service_stack_watch.db_api,
+                       'watch_rule_get_all_by_stack')
+    @mock.patch.object(service_stack_watch.db_api, 'watch_rule_update')
+    def test_periodic_watch_task_created_nested(self, watch_rule_update,
+                                                watch_rule_get_all_by_stack,
+                                                stack_get_all_by_owner_id):
+        stack_id = 90
+
+        def my_wr_get(cnxt, sid):
+            if sid == stack_id:
+                return []
+            wr1 = mock.Mock()
+            wr1.id = 4
+            wr1.state = rpc_api.WATCH_STATE_NODATA
+            return [wr1]
+
+        watch_rule_get_all_by_stack.side_effect = my_wr_get
+
+        def my_nested_get(cnxt, sid):
+            if sid == stack_id:
+                nested_stack = mock.Mock()
+                nested_stack.id = 55
+                return [nested_stack]
+            return []
+
+        stack_get_all_by_owner_id.side_effect = my_nested_get
+        tg = mock.Mock()
+        sw = service_stack_watch.StackWatch(tg)
+        sw.start_watch_task(stack_id, self.ctx)
+
+        # assert that add_timer IS called.
+        self.assertEqual([mock.call(stack_id, sw.periodic_watcher_task,
+                                    sid=stack_id)],
+                         tg.add_timer.call_args_list)