heat engine allow WatchRule load() from DB object

Allow WatchRule.load to initialize an object based on an existing
sqlalchemy DB object, similar to parser.Stack, avoids doing two
DB lookups when running the periodic watch tasks

Change-Id: I280942b81e5fdee17acf5582e3d319045afa7914
Signed-off-by: Steven Hardy <shardy@redhat.com>

diff --git a/heat/engine/service.py b/heat/engine/service.py
index 8b75894158e437ed94430f0c825870b35ce73cf0..83098780ced13e238dee3bd804c3be74a27ca305 100644 (file)
--- a/heat/engine/service.py
+++ b/heat/engine/service.py
@@ -397,14 +397,13 @@ class EngineService(service.Service):
 
     def _periodic_watcher_task(self, context, sid):
         try:
-            wrn = [w.name for w in
-                   db_api.watch_rule_get_all_by_stack(context, sid)]
+            wrs = db_api.watch_rule_get_all_by_stack(context, sid)
         except Exception as ex:
             logger.warn('periodic_task db error (%s) %s' %
                         ('watch rule removed?', str(ex)))
             return
-        for wr in wrn:
-            rule = watchrule.WatchRule.load(context, wr)
+        for wr in wrs:
+            rule = watchrule.WatchRule.load(context, watch=wr)
             rule.evaluate()
 
     def create_watch_data(self, context, watch_name, stats_data):

diff --git a/heat/engine/watchrule.py b/heat/engine/watchrule.py
index 3ff90840ca72e3bcb6d4bcd800260d4cbae9dee1..09a278e96fcf9c779afadf2d8e339509a72d69cb 100644 (file)
--- a/heat/engine/watchrule.py
+++ b/heat/engine/watchrule.py
@@ -53,27 +53,27 @@ class WatchRule(object):
         self.last_evaluated = last_evaluated
 
     @classmethod
-    def load(cls, context, watch_name):
+    def load(cls, context, watch_name=None, watch=None):
         '''
-        Load the watchrule from the DB by name
+        Load the watchrule object, either by name or via an existing DB object
         '''
-        dbwr = None
-        try:
-            dbwr = db_api.watch_rule_get_by_name(context, watch_name)
-        except Exception as ex:
-            logger.warn('show_watch (%s) db error %s' %
-                        (watch_name, str(ex)))
-        if not dbwr:
+        if watch == None:
+            try:
+                watch = db_api.watch_rule_get_by_name(context, watch_name)
+            except Exception as ex:
+                logger.warn('WatchRule.load (%s) db error %s' %
+                            (watch_name, str(ex)))
+        if watch == None:
             raise AttributeError('Unknown watch name %s' % watch_name)
         else:
             return cls(context=context,
-                       watch_name=dbwr.name,
-                       rule=dbwr.rule,
-                       stack_id=dbwr.stack_id,
-                       state=dbwr.state,
-                       wid=dbwr.id,
-                       watch_data=dbwr.watch_data,
-                       last_evaluated=dbwr.last_evaluated)
+                       watch_name=watch.name,
+                       rule=watch.rule,
+                       stack_id=watch.stack_id,
+                       state=watch.state,
+                       wid=watch.id,
+                       watch_data=watch.watch_data,
+                       last_evaluated=watch.last_evaluated)
 
     def store(self):
         '''