Fixes cooldown logic throws ValueError

Change-Id: I2835e8b2b570a82625761aa55ec34e0df4d6ecd5
Closes-bug: #1569273
(cherry picked from commit 080ace0054682494134a5bca5921fe937abdbe99)

2 files changed, 26 insertions, 10 deletions

diff --git a/heat/scaling/cooldown.py b/heat/scaling/cooldown.py
index effa4e6b3..fd874badb 100644
--- a/heat/scaling/cooldown.py
+++ b/heat/scaling/cooldown.py
@@ -33,16 +33,22 @@ class CooldownMixin(object):
             # If not specified, it will be None, same as cooldown == 0
             cooldown = 0
 
-        if 'cooldown' not in metadata:
-            # Note: this is for supporting old version cooldown checking
-            if metadata and cooldown != 0:
-                last_adjust = next(six.iterkeys(metadata))
-                if not timeutils.is_older_than(last_adjust, cooldown):
-                    return False
-        elif cooldown != 0:
-            last_adjust = next(six.iterkeys(metadata['cooldown']))
-            if not timeutils.is_older_than(last_adjust, cooldown):
-                return False
+        if cooldown != 0:
+            try:
+                if 'cooldown' not in metadata:
+                    # Note: this is for supporting old version cooldown logic
+                    if metadata:
+                        last_adjust = next(six.iterkeys(metadata))
+                        if not timeutils.is_older_than(last_adjust, cooldown):
+                            return False
+                else:
+                    last_adjust = next(six.iterkeys(metadata['cooldown']))
+                    if not timeutils.is_older_than(last_adjust, cooldown):
+                        return False
+            except ValueError:
+                # occurs when metadata has only {scaling_in_progress: False}
+                pass
+
         # Assumes _finished_scaling is called
         # after the scaling operation completes
         metadata['scaling_in_progress'] = True
diff --git a/heat/tests/autoscaling/test_heat_scaling_policy.py b/heat/tests/autoscaling/test_heat_scaling_policy.py
index ae5020c1e..bbaf46bb0 100644
--- a/heat/tests/autoscaling/test_heat_scaling_policy.py
+++ b/heat/tests/autoscaling/test_heat_scaling_policy.py
@@ -197,6 +197,16 @@ class TestCooldownMixin(common.HeatTestCase):
         self.patchobject(pol, 'metadata_get', return_value=previous_meta)
         self.assertTrue(pol._is_scaling_allowed())
 
+    def test_no_cooldown_no_scaling_in_progress(self):
+        t = template_format.parse(as_template)
+        stack = utils.parse_stack(t, params=as_params)
+        pol = self.create_scaling_policy(t, stack, 'my-policy')
+
+        # no cooldown entry in the metadata
+        previous_meta = {'scaling_in_progress': False}
+        self.patchobject(pol, 'metadata_get', return_value=previous_meta)
+        self.assertTrue(pol._is_scaling_allowed())
+
     def test_metadata_is_written(self):
         t = template_format.parse(as_template)
         stack = utils.parse_stack(t, params=as_params)