add wrapper method for yaml_parse

Author: troyready

stacker/actions/diff.py

@@ -7,7 +7,7 @@
 from .base import plan, build_walker
 from . import build
 from .. import exceptions
-from ..awscli_yamlhelper import yaml_parse
+from ..util import parse_cloudformation_template
 from ..status import NotSubmittedStatus, NotUpdatedStatus, COMPLETE
 
 logger = logging.getLogger(__name__)
@@ -227,13 +227,13 @@ def _diff_stack(self, stack, **kwargs):
             self._print_new_stack(new_stack, parameters)
         else:
             # Diff our old & new stack/parameters
-            old_template = yaml_parse(old_template)
+            old_template = parse_cloudformation_template(old_template)
             if isinstance(old_template, (str, unicode)):
                 # YAML templates returned from CFN need parsing again
                 # "AWSTemplateFormatVersion: \"2010-09-09\"\nParam..."
                 # ->
                 # AWSTemplateFormatVersion: "2010-09-09"
-                old_template = yaml_parse(old_template)
+                old_template = parse_cloudformation_template(old_template)
             old_stack = self._normalize_json(
                 json.dumps(old_template,
                            sort_keys=True,

stacker/blueprints/raw.py

@@ -3,7 +3,7 @@
 import hashlib
 import json
 
-from ..awscli_yamlhelper import yaml_parse
+from ..util import parse_cloudformation_template
 from ..exceptions import MissingVariable, UnresolvedVariable
 
 
@@ -100,7 +100,7 @@ def to_dict(self):
             dict: the loaded template as a python dictionary
 
         """
-        return yaml_parse(self.rendered)
+        return parse_cloudformation_template(self.rendered)
 
     def render_template(self):
         """Load template and generate its md5 hash."""

stacker/tests/test_util.py

@@ -19,6 +19,7 @@
     get_client_region,
     get_s3_endpoint,
     s3_bucket_location_constraint,
+    parse_cloudformation_template,
     Extractor,
     TarExtractor,
     TarGzipExtractor,
@@ -144,6 +145,45 @@ def test_s3_bucket_location_constraint(self):
                 result
             )
 
+    def test_parse_cloudformation_template(self):
+        template = """AWSTemplateFormatVersion: "2010-09-09"
+Parameters:
+  Param1:
+    Type: String
+Resources:
+  Bucket:
+    Type: AWS::S3::Bucket
+    Properties:
+      BucketName:
+        !Join
+          - "-"
+          - - !Ref "AWS::StackName"
+            - !Ref "AWS::Region"
+Outputs:
+  DummyId:
+    Value: dummy-1234"""
+        parsed_template = {
+            'AWSTemplateFormatVersion': '2010-09-09',
+            'Outputs': {'DummyId': {'Value': 'dummy-1234'}},
+            'Parameters': {'Param1': {'Type': 'String'}},
+            'Resources': {
+                'Bucket': {'Type': 'AWS::S3::Bucket',
+                           'Properties': {
+                               'BucketName': {
+                                   u'Fn::Join': [
+                                       '-',
+                                       [{u'Ref': u'AWS::StackName'},
+                                        {u'Ref': u'AWS::Region'}]
+                                   ]
+                               }
+                           }}
+            }
+        }
+        self.assertEqual(
+            parse_cloudformation_template(template),
+            parsed_template
+        )
+
     def test_extractors(self):
         self.assertEqual(Extractor('test.zip').archive, 'test.zip')
         self.assertEqual(TarExtractor().extension(), '.tar')

stacker/util.py

@@ -22,6 +22,7 @@
 from yaml.constructor import ConstructorError
 from yaml.nodes import MappingNode
 
+from .awscli_yamlhelper import yaml_parse
 from stacker.session_cache import get_session
 
 logger = logging.getLogger(__name__)
@@ -497,6 +498,17 @@ def ensure_s3_bucket(s3_client, bucket_name, bucket_region):
             raise
 
 
+def parse_cloudformation_template(template):
+    """Parse CFN template string.
+
+    Leverages the vendored aws-cli yamlhelper to handle JSON or YAML templates.
+
+    Args:
+        template (str): The template body.
+    """
+    return yaml_parse(template)
+
+
 class Extractor(object):
     """Base class for extractors."""