From f22691904ff4459629daf842390fd6fea94b049e Mon Sep 17 00:00:00 2001
From: Zane Bitter <zbitter@redhat.com>
Date: Thu, 13 Jun 2013 20:03:27 +0200
Subject: [PATCH] scheduler: Simplify DependencyTaskGroup interface

Instead of passing a function that takes one argument and returns a task
that takes no arguments, simply pass a task that takes one argument.

Change-Id: I73d5f137d5db492c09e6887f80e7e759734c211f
---
 heat/engine/parser.py        |  2 +-
 heat/engine/scheduler.py     | 17 ++++++++++-------
 heat/tests/test_scheduler.py | 12 +-----------
 3 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/heat/engine/parser.py b/heat/engine/parser.py
index 974b8eb1c0..05341c5821 100644
--- a/heat/engine/parser.py
+++ b/heat/engine/parser.py
@@ -294,7 +294,7 @@ class Stack(object):
         res = None
 
         def resource_create(r):
-            return r.create
+            return r.create()
 
         create_task = scheduler.DependencyTaskGroup(self.dependencies,
                                                     resource_create)
diff --git a/heat/engine/scheduler.py b/heat/engine/scheduler.py
index 6857c9bb44..ab98748273 100644
--- a/heat/engine/scheduler.py
+++ b/heat/engine/scheduler.py
@@ -263,19 +263,22 @@ class DependencyTaskGroup(object):
     A task which manages a group of subtasks that have ordering dependencies.
     """
 
-    def __init__(self, dependencies, make_task=lambda o: o,
+    def __init__(self, dependencies, task=lambda o: o(),
                  reverse=False, name=None):
         """
-        Initialise with the task dependencies and (optionally) a function for
-        creating a task from each dependency object.
+        Initialise with the task dependencies and (optionally) a task to run on
+        each.
+
+        If no task is supplied, it is assumed that the tasks are stored
+        directly in the dependency tree. If a task is supplied, the object
+        stored in the dependency tree is passed as an argument.
         """
-        self._runners = dict((o, TaskRunner(make_task(o)))
-                             for o in dependencies)
+        self._runners = dict((o, TaskRunner(task, o)) for o in dependencies)
         self._graph = dependencies.graph(reverse=reverse)
 
         if name is None:
-            name = '(%s) %s' % (getattr(make_task, '__name__',
-                                        task_description(make_task)),
+            name = '(%s) %s' % (getattr(task, '__name__',
+                                        task_description(task)),
                                 str(dependencies))
         self.name = name
 
diff --git a/heat/tests/test_scheduler.py b/heat/tests/test_scheduler.py
index b7c54f6ed3..7d12c912f2 100644
--- a/heat/tests/test_scheduler.py
+++ b/heat/tests/test_scheduler.py
@@ -166,19 +166,9 @@ class DependencyTaskGroupTest(mox.MoxTestBase):
     def _dep_test(self, *edges):
         dummy = DummyTask(getattr(self, 'steps', 3))
 
-        class TaskMaker(object):
-            def __init__(self, name):
-                self.name = name
-
-            def __repr__(self):
-                return 'Dummy task "%s"' % self.name
-
-            def __call__(self, *args, **kwargs):
-                return dummy(self.name, *args, **kwargs)
-
         deps = dependencies.Dependencies(edges)
 
-        tg = scheduler.DependencyTaskGroup(deps, TaskMaker)
+        tg = scheduler.DependencyTaskGroup(deps, dummy)
 
         self.mox.StubOutWithMock(dummy, 'do_step')