Move template_format from heat to heatclient

heatclient needs to (YAML) parse the template to allow it to populate
the content for get_files function calls. For this reason, template_format
(and environment_format) have been moved to heatclient so this code can be
shared by both heat and heatclient.

Change-Id: I3cc11cd57256ad539efb4dab314ac07547e9e6a2

1 files changed, 80 insertions, 0 deletions

diff --git a/heatclient/common/template_format.py b/heatclient/common/template_format.py
new file mode 100644
index 0000000..0a7432f
--- /dev/null
+++ b/heatclient/common/template_format.py
@@ -0,0 +1,80 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import json
+import yaml
+
+HEAT_VERSIONS = (u'2012-12-12',)
+CFN_VERSIONS = (u'2010-09-09',)
+
+if hasattr(yaml, 'CSafeLoader'):
+    yaml_loader = yaml.CSafeLoader
+else:
+    yaml_loader = yaml.SafeLoader
+
+if hasattr(yaml, 'CSafeDumper'):
+    yaml_dumper = yaml.CSafeDumper
+else:
+    yaml_dumper = yaml.SafeDumper
+
+
+def _construct_yaml_str(self, node):
+    # Override the default string handling function
+    # to always return unicode objects
+    return self.construct_scalar(node)
+yaml_loader.add_constructor(u'tag:yaml.org,2002:str', _construct_yaml_str)
+# Unquoted dates like 2013-05-23 in yaml files get loaded as objects of type
+# datetime.data which causes problems in API layer when being processed by
+# openstack.common.jsonutils. Therefore, make unicode string out of timestamps
+# until jsonutils can handle dates.
+yaml_loader.add_constructor(u'tag:yaml.org,2002:timestamp',
+                            _construct_yaml_str)
+
+
+def parse(tmpl_str):
+    '''Takes a string and returns a dict containing the parsed structure.
+
+    This includes determination of whether the string is using the
+    JSON or YAML format.
+    '''
+    if tmpl_str.startswith('{'):
+        tpl = json.loads(tmpl_str)
+    else:
+        try:
+            tpl = yaml.load(tmpl_str, Loader=yaml_loader)
+        except yaml.YAMLError as yea:
+            raise ValueError(yea)
+        else:
+            if tpl is None:
+                tpl = {}
+            if u'heat_template_version' not in tpl:
+                default_for_missing(tpl, u'HeatTemplateFormatVersion',
+                                    HEAT_VERSIONS)
+    return tpl
+
+
+def default_for_missing(tpl, version_param, versions):
+    '''Checks a parsed template for missing version and sections.
+
+    This is currently only applied to YAML templates.
+    '''
+    # if version is missing, implicitly use the lastest one
+    if version_param not in tpl:
+        tpl[version_param] = versions[-1]
+
+    # create empty placeholders for any of the main dict sections
+    for param in (u'Parameters', u'Mappings', u'Resources', u'Outputs'):
+        if param not in tpl:
+            tpl[param] = {}