validate_template returns whole Parameters snippet

Currently the engine validate_template returns cfn formatted
Parameters from the template, which isn't actually very useful
to build a full UI from a validate call.

This change returns the original Parameters template snippet
and changes the cfn api to reformat to the CFN API legacy format.

The Parameters section of the RPC and the REST APIs now return
a dictionary containing the parameters as specified in the template.
Previously the Parameters section contained a list in the CFN API
format.

Pseudo parameters are filtered out of the validate results.

Change-Id: Iea53dc847ff13f5f479ec3a66bcf141c4ccaeb25
Fixes: bug #1157537

heat/api/cfn/v1/stacks.py

@@ -403,8 +403,23 @@ class StackController(object):
             return exception.HeatInvalidParameterValueError(detail=msg)
 
         logger.info('validate_template')
+
+        def format_validate_parameter(key, value):
+            """
+            Reformat engine output into the AWS "ValidateTemplate" format
+            """
+
+            return {
+                'ParameterKey': key,
+                'DefaultValue': value.get(engine_api.PARAM_DEFAULT, ''),
+                'Description': value.get(engine_api.PARAM_DESCRIPTION, ''),
+                'NoEcho': value.get(engine_api.PARAM_NO_ECHO, 'false')
+            }
+
         try:
             res = self.engine_rpcapi.validate_template(con, template)
+            res['Parameters'] = [format_validate_parameter(k, v)
+                                 for k, v in res['Parameters'].items()]
             return api_utils.format_response('ValidateTemplate', res)
         except rpc_common.RemoteError as ex:
             return exception.map_remote_error(ex)

heat/engine/service.py

@@ -26,6 +26,7 @@ from heat.engine import clients
 from heat.engine.event import Event
 from heat.common import exception
 from heat.common import identifier
+from heat.engine import parameters
 from heat.engine import parser
 from heat.engine import resource
 from heat.engine import resources  # pyflakes_bypass review 23102
@@ -286,20 +287,14 @@ class EngineService(service.Service):
                 return {'Error':
                         'Every Resources object must contain a Type member.'}
 
-        def describe_param(p):
-            description = {'NoEcho': p.no_echo() and 'true' or 'false',
-                           'ParameterKey': p.name,
-                           'Description': p.description()}
-            if p.has_default():
-                description['DefaultValue'] = p.default()
-
-            return description
-
-        params = parser.Parameters(None, tmpl).map(describe_param)
+        tmpl_params = parser.Parameters(None, tmpl)
+        format_validate_parameter = lambda p: dict(p.schema)
+        is_real_param = lambda p: p.name not in parameters.PSEUDO_PARAMETERS
+        params = tmpl_params.map(format_validate_parameter, is_real_param)
 
         result = {
             'Description': template.get('Description', ''),
-            'Parameters': params.values(),
+            'Parameters': params,
         }
         return result
 

heat/rpc/api.py

@@ -127,3 +127,15 @@ WATCH_DATA_KEYS = (
     'watch_name', 'metric_name', 'timestamp',
     'namespace', 'data'
 )
+
+VALIDATE_PARAM_KEYS = (
+    PARAM_TYPE, PARAM_DEFAULT, PARAM_NO_ECHO,
+    PARAM_ALLOWED_VALUES, PARAM_ALLOWED_PATTERN, PARAM_MAX_LENGTH,
+    PARAM_MIN_LENGTH, PARAM_MAX_VALUE, PARAM_MIN_VALUE,
+    PARAM_DESCRIPTION, PARAM_CONSTRAINT_DESCRIPTION
+) = (
+    'Type', 'Default', 'NoEcho',
+    'AllowedValues', 'AllowedPattern', 'MaxLength',
+    'MinLength', 'MaxValue', 'MinValue',
+    'Description', 'ConstraintDescription'
+)

heat/tests/test_validate.py

@@ -288,3 +288,17 @@ class validateTest(unittest.TestCase):
         engine = service.EngineService('a', 't')
         res = dict(engine.validate_template(None, t))
         self.assertNotEqual(res['Description'], 'Successfully validated')
+
+    def test_validate_parameters(self):
+        t = template_format.parse(test_template_ref % 'WikiDatabase')
+
+        self.m.StubOutWithMock(instances.Instance, 'nova')
+        instances.Instance.nova().AndReturn(self.fc)
+        self.m.ReplayAll()
+
+        engine = service.EngineService('a', 't')
+        res = dict(engine.validate_template(None, t))
+        self.assertEqual(res['Parameters'], {'KeyName': {
+            'Type': 'String',
+            'Description': 'Name of an existing EC2KeyPair to enable SSH '
+                           'access to the instances'}})