Merge "Deploy templates: fix updating steps in Python 3"

ironic/db/sqlalchemy/api.py

@@ -16,6 +16,7 @@
 
 import collections
 import datetime
+import json
 import threading
 
 from oslo_db import api as oslo_db_api
@@ -1848,7 +1849,11 @@ class Connection(api.Connection):
 
         def _step_key(step):
             """Compare two deploy template steps."""
-            return step.interface, step.step, step.args, step.priority
+            # NOTE(mgoddard): In python 3, dicts are not orderable so cannot be
+            # used as a sort key. Serialise the step arguments to a JSON string
+            # for comparison. Taken from https://stackoverflow.com/a/22003440.
+            sortable_args = json.dumps(step.args, sort_keys=True)
+            return step.interface, step.step, sortable_args, step.priority
 
         # List all existing steps for the template.
         current_steps = (model_query(models.DeployTemplateStep)

ironic/tests/unit/db/test_deploy_templates.py

@@ -100,6 +100,15 @@ class DbDeployTemplateTestCase(base.DbTestCase):
         self.assertEqual({}, step1.args)
         self.assertEqual(50, step1.priority)
 
+    def test_update_steps_replace_args(self):
+        step = self.template.steps[0]
+        step['args'] = {'foo': 'bar'}
+        values = {'steps': [step]}
+        template = self.dbapi.update_deploy_template(self.template.id, values)
+        self.assertEqual(1, len(template.steps))
+        step = template.steps[0]
+        self.assertEqual({'foo': 'bar'}, step.args)
+
     def test_update_steps_remove_all(self):
         values = {'steps': []}
         template = self.dbapi.update_deploy_template(self.template.id, values)