Invalid instance_snapshot causes KeyError

When creating a nova instance, if the instance_snapshot_id passed in is
invalid, a KeyError exception results.  This likely happens when another
window or perhaps a command line tool deletes the snapshot before the
page is posted back.  Memoize decorator fix fixes an error which masks
the error listed above, enabling better debugging.

Closes-Bug: 1386826
Change-Id: I195b4df84da3bd360b155db9ae733c34575ebe7e

horizon/utils/memoized.py

@@ -94,7 +94,7 @@ def memoized(func):
             # we can't cache anything and simply always call the decorated
             # function.
             warnings.warn(
-                "The key %r is not hashable and cannot be memoized." % key,
+                "The key %r is not hashable and cannot be memoized." % (key,),
                 UnhashableKeyWarning, 2)
             value = func(*args, **kwargs)
         return value

openstack_dashboard/dashboards/project/instances/tests.py

@@ -2021,6 +2021,98 @@ class InstanceTests(helpers.TestCase):
         self.test_launch_instance_post_no_images_available(
             test_with_profile=True)
 
+    @helpers.create_stubs({
+        api.glance: ('image_list_detailed',),
+        api.neutron: ('network_list',
+                      'profile_list',
+                      'port_create',),
+        api.nova: ('extension_supported',
+                   'flavor_list',
+                   'keypair_list',
+                   'availability_zone_list',
+                   'server_create',),
+        api.network: ('security_group_list',),
+        cinder: ('volume_list',
+                 'volume_snapshot_list',),
+        quotas: ('tenant_quota_usages',)})
+    def test_launch_instance_post_boot_from_snapshot(
+        self,
+        test_with_profile=False,
+    ):
+        flavor = self.flavors.first()
+        keypair = self.keypairs.first()
+        server = self.servers.first()
+        avail_zone = self.availability_zones.first()
+        quota_usages = self.quota_usages.first()
+
+        api.nova.extension_supported('BlockDeviceMappingV2Boot',
+                                     IsA(http.HttpRequest)) \
+            .AndReturn(True)
+        api.nova.flavor_list(IsA(http.HttpRequest)) \
+            .AndReturn(self.flavors.list())
+        api.glance.image_list_detailed(IsA(http.HttpRequest),
+                                       filters={'is_public': True,
+                                                'status': 'active'}) \
+            .AndReturn([[], False, False])
+        api.glance.image_list_detailed(
+            IsA(http.HttpRequest),
+            filters={'property-owner_id': self.tenant.id,
+                     'status': 'active'}) \
+            .AndReturn([[], False, False])
+        api.neutron.network_list(IsA(http.HttpRequest),
+                                 tenant_id=self.tenant.id,
+                                 shared=False) \
+            .AndReturn(self.networks.list()[:1])
+        api.neutron.network_list(IsA(http.HttpRequest),
+                                 shared=True) \
+            .AndReturn(self.networks.list()[1:])
+        api.nova.flavor_list(IsA(http.HttpRequest)) \
+            .AndReturn(self.flavors.list())
+        api.nova.keypair_list(IsA(http.HttpRequest)) \
+            .AndReturn(self.keypairs.list())
+        api.network.security_group_list(IsA(http.HttpRequest)) \
+            .AndReturn(self.security_groups.list())
+        api.nova.availability_zone_list(IsA(http.HttpRequest)) \
+            .AndReturn(self.availability_zones.list())
+        api.nova.extension_supported('DiskConfig',
+                                     IsA(http.HttpRequest)) \
+            .AndReturn(True)
+        api.nova.extension_supported('ConfigDrive',
+                                     IsA(http.HttpRequest)).AndReturn(True)
+
+        cinder.volume_snapshot_list(IsA(http.HttpRequest)).AndReturn([])
+
+        cinder.volume_list(IsA(http.HttpRequest)) \
+            .AndReturn([])
+
+        quotas.tenant_quota_usages(IsA(http.HttpRequest)) \
+            .AndReturn(quota_usages)
+
+        self.mox.ReplayAll()
+
+        bad_snapshot_id = 'a-bogus-id'
+
+        form_data = {'flavor': flavor.id,
+                     'source_type': 'instance_snapshot_id',
+                     'instance_snapshot_id': bad_snapshot_id,
+                     'keypair': keypair.name,
+                     'name': server.name,
+                     'script_source': 'raw',
+                     'availability_zone': avail_zone.zoneName,
+                     'network': self.networks.first().id,
+                     'volume_id': '',
+                     'volume_snapshot_id': '',
+                     'image_id': '',
+                     'device_name': 'vda',
+                     'count': 1,
+                     'profile': '',
+                     'customization_script': ''}
+
+        url = reverse('horizon:project:instances:launch')
+        res = self.client.post(url, form_data)
+
+        self.assertFormErrors(res, 1, "You must select a snapshot.")
+
     @helpers.create_stubs({api.glance: ('image_list_detailed',),
                            api.neutron: ('network_list',
                                          'profile_list',),

openstack_dashboard/dashboards/project/instances/workflows/create_instance.py

@@ -290,7 +290,9 @@ class SetInstanceDetailsAction(workflows.Action):
                                 [msg])
 
         elif source_type == 'instance_snapshot_id':
-            if not cleaned_data['instance_snapshot_id']:
+            # using the array form of get blows up with KeyError
+            # if instance_snapshot_id is nil
+            if not cleaned_data.get('instance_snapshot_id'):
                 msg = _("You must select a snapshot.")
                 self._errors['instance_snapshot_id'] = self.error_class([msg])