Add an add_output() method to Template

This helps with dynamically building templates, and is similar to the
add_resource method.

Change-Id: I51ce5c913438083d6d43eb6d8a8bf55cfa8ea3ee
Related-Bug: #1660831

heat/engine/cfn/template.py

@@ -75,6 +75,9 @@ class CfnTemplateBase(template_common.CommonTemplate):
                             'deletion_policy': RES_DELETION_POLICY,
                             'update_policy': RES_UPDATE_POLICY}
 
+    HOT_TO_CFN_OUTPUT_ATTRS = {'description': OUTPUT_DESCRIPTION,
+                               'value': OUTPUT_VALUE}
+
     def __getitem__(self, section):
         """Get the relevant section in the template."""
         if section not in self.SECTIONS:
@@ -157,6 +160,15 @@ class CfnTemplateBase(template_common.CommonTemplate):
             self.t[self.RESOURCES] = {}
         self.t[self.RESOURCES][name] = cfn_tmpl
 
+    def add_output(self, definition):
+        hot_op = definition.render_hot()
+        cfn_op = dict((self.HOT_TO_CFN_OUTPUT_ATTRS[k], v)
+                      for k, v in hot_op.items())
+
+        if self.t.get(self.OUTPUTS) is None:
+            self.t[self.OUTPUTS] = {}
+        self.t[self.OUTPUTS][definition.name] = cfn_op
+
 
 class CfnTemplate(CfnTemplateBase):
 

heat/engine/hot/template.py

@@ -268,6 +268,11 @@ class HOTemplate20130523(template_common.CommonTemplate):
             self.t[self.RESOURCES] = {}
         self.t[self.RESOURCES][name] = definition.render_hot()
 
+    def add_output(self, definition):
+        if self.t.get(self.OUTPUTS) is None:
+            self.t[self.OUTPUTS] = {}
+        self.t[self.OUTPUTS][definition.name] = definition.render_hot()
+
 
 class HOTemplate20141016(HOTemplate20130523):
     functions = {

heat/engine/output.py

@@ -11,6 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import copy
 import six
 
 from heat.engine import function
@@ -49,3 +50,10 @@ class OutputDefinition(object):
             return 'No description given'
 
         return six.text_type(self._description)
+
+    def render_hot(self):
+        def items():
+            if self._description is not None:
+                yield 'description', self._description
+            yield 'value', copy.deepcopy(self._value)
+        return dict(items())

heat/engine/template.py

@@ -255,6 +255,13 @@ class Template(collections.Mapping):
         """
         pass
 
+    def add_output(self, definition):
+        """Add an output to the template.
+
+        The output is passed as a OutputDefinition object.
+        """
+        raise NotImplementedError
+
     def remove_resource(self, name):
         """Remove a resource from the template."""
         self.t.get(self.RESOURCES, {}).pop(name)

heat/tests/test_hot.py

@@ -1857,6 +1857,23 @@ conditions:
 
         self.assertEqual(hot_tpl['resources'], empty.t['resources'])
 
+    def test_add_output(self):
+        hot_tpl = template_format.parse('''
+        heat_template_version: 2013-05-23
+        outputs:
+          output1:
+            description: An output
+            value: bar
+        ''')
+        source = template.Template(hot_tpl)
+        empty = template.Template(copy.deepcopy(hot_tpl_empty))
+        stack = parser.Stack(utils.dummy_context(), 'test_stack', source)
+
+        for defn in six.itervalues(source.outputs(stack)):
+            empty.add_output(defn)
+
+        self.assertEqual(hot_tpl['outputs'], empty.t['outputs'])
+
     def test_filter(self):
         snippet = {'filter': [[None], [1, None, 4, 2, None]]}
         tmpl = template.Template(hot_ocata_tpl_empty)

heat/tests/test_template.py

@@ -1429,6 +1429,23 @@ class TemplateTest(common.HeatTestCase):
 
         self.assertEqual(cfn_tpl['Resources'], empty.t['Resources'])
 
+    def test_add_output(self):
+        cfn_tpl = template_format.parse('''
+        AWSTemplateFormatVersion: 2010-09-09
+        Outputs:
+          output1:
+            Description: An output
+            Value: foo
+        ''')
+        source = template.Template(cfn_tpl)
+        empty = template.Template(copy.deepcopy(empty_template))
+        stk = stack.Stack(self.ctx, 'test_stack', source)
+
+        for defn in six.itervalues(source.outputs(stk)):
+            empty.add_output(defn)
+
+        self.assertEqual(cfn_tpl['Outputs'], empty.t['Outputs'])
+
     def test_create_empty_template_default_version(self):
         empty_template = template.Template.create_empty_template()
         self.assertEqual(hot_t.HOTemplate20150430, empty_template.__class__)