Use pydoc for formatting docstrings

pydoc is part of the standard library and is much more robust at formatting
docstings than any trivial hand-rolled munger could be. For example, it
correctly preserves indentation within the docstring. Use it when
generating descriptions from docstrings for the API.

Change-Id: Ib565a64d990a45c652a9475255c37805f86070b4

heat/engine/api.py

@@ -625,10 +625,3 @@ def format_snapshot(snapshot):
             heat_timeutils.isotime(snapshot.created_at),
     }
     return result
-
-
-def build_resource_description(docstring):
-    if docstring is not None:
-        return '\n'.join(map(lambda x: x.strip(), docstring.split('\n')))
-    else:
-        return _('No description given')

heat/engine/environment.py

@@ -636,18 +636,18 @@ class ResourceRegistry(object):
             return (version is None or
                     cls.get_class().support_status.version == version)
 
-        def resource_description(name, cls, with_description):
+        import heat.engine.resource
+
+        def resource_description(name, info, with_description):
             if not with_description:
                 return name
-            if cls.description == 'Plugin':
-                rsrc = cls.value
-            elif cls.description == 'Template':
-                rsrc = cls.get_class()
-            else:
-                rsrc = None
+            rsrc_cls = info.get_class()
+            if rsrc_cls is None:
+                rsrc_cls = heat.engine.resource.Resource
             return {
                 'resource_type': name,
-                'description': rsrc.__doc__}
+                'description': rsrc_cls.getdoc(),
+            }
 
         return [resource_description(name, cls, with_description)
                 for name, cls in six.iteritems(self._registry)

heat/engine/resource.py

@@ -14,6 +14,7 @@
 import base64
 import contextlib
 import datetime as dt
+import pydoc
 import weakref
 
 from oslo_config import cfg
@@ -310,6 +311,12 @@ class Resource(object):
     def external_id(self):
         return self.t.external_id()
 
+    @classmethod
+    def getdoc(cls):
+        if cls.__doc__ is None:
+            return _('No description available')
+        return pydoc.getdoc(cls)
+
     @property
     def stack(self):
         stack = self._stackref()

heat/engine/service.py

@@ -16,6 +16,7 @@ import datetime
 import functools
 import itertools
 import os
+import pydoc
 import socket
 
 import eventlet
@@ -1533,10 +1534,6 @@ class EngineService(service.ServiceBase):
             type_name=type_name,
             version=heat_version,
             with_description=with_description)
-        if with_description:
-            for resource_type in result:
-                resource_type['description'] = api.build_resource_description(
-                    resource_type['description'])
         return result
 
     def list_template_versions(self, cnxt):
@@ -1591,10 +1588,7 @@ class EngineService(service.ServiceBase):
         functions = []
         for func_name, func in six.iteritems(supported_funcs):
             if func is not hot_functions.Removed:
-                if func.__doc__.split('\n')[0]:
-                    desc = func.__doc__.split('\n')[0].strip()
-                else:
-                    desc = func.__doc__.split('\n')[1].strip()
+                desc = pydoc.splitdoc(pydoc.getdoc(func))[0]
                 functions.append(
                     {'functions': func_name,
                      'description': desc}
@@ -1617,6 +1611,8 @@ class EngineService(service.ServiceBase):
                           type_name)
             raise exception.InvalidGlobalResource(type_name=type_name)
 
+        assert resource_class is not None
+
         if resource_class.support_status.status == support.HIDDEN:
             raise exception.NotSupported(feature=type_name)
 
@@ -1657,9 +1653,7 @@ class EngineService(service.ServiceBase):
                 resource_class.support_status.to_dict()
         }
         if with_description:
-            docstring = resource_class.__doc__
-            description = api.build_resource_description(docstring)
-            result[rpc_api.RES_SCHEMA_DESCRIPTION] = description
+            result[rpc_api.RES_SCHEMA_DESCRIPTION] = resource_class.getdoc()
         return result
 
     def generate_template(self, cnxt, type_name, template_type='cfn'):

heat/tests/engine/test_resource_type.py

@@ -76,14 +76,14 @@ class ResourceTypeTest(common.HeatTestCase):
         description = ("Heat Template Resource for Designate Domain.\n\n"
                        "Designate provides DNS-as-a-Service services for "
                        "OpenStack. So, domain\nis a realm with an "
-                       "identification string, unique in DNS.\n")
+                       "identification string, unique in DNS.")
         self.assertIn({'resource_type': 'OS::Designate::Domain',
                        'description': description}, resources)
         self.assertIn({'resource_type': 'AWS::RDS::DBInstance',
                        'description': 'Builtin AWS::RDS::DBInstance'},
                       resources)
         self.assertIn({'resource_type': 'AWS::EC2::Instance',
-                       'description': 'No description given'},
+                       'description': 'No description available'},
                       resources)
 
     def test_resource_schema(self):
@@ -117,7 +117,7 @@ class ResourceTypeTest(common.HeatTestCase):
                 'message': None,
                 'previous_status': None
             },
-            'description': 'No description given'
+            'description': 'No description available'
         }
 
         schema = self.eng.resource_schema(self.ctx, type_name=type_name,