diff --git a/heat/api/openstack/v1/stacks.py b/heat/api/openstack/v1/stacks.py
index f149e720bc..b051d60b9a 100644
--- a/heat/api/openstack/v1/stacks.py
+++ b/heat/api/openstack/v1/stacks.py
@@ -15,6 +15,7 @@
 Stack endpoint for Heat v1 ReST API.
 """
 
+import contextlib
 from oslo_log import log as logging
 import six
 from six.moves.urllib import parse
@@ -69,17 +70,10 @@ class InstantiationData(object):
             self.data[rpc_api.PARAM_EXISTING] = True
 
     @staticmethod
-    def format_parse(data, data_type):
-        """
-        Parse the supplied data as JSON or YAML, raising the appropriate
-        exception if it is in the wrong format.
-        """
-
+    @contextlib.contextmanager
+    def parse_error_check(data_type):
         try:
-            if data_type == 'Environment':
-                return environment_format.parse(data)
-            else:
-                return template_format.parse(data)
+            yield
         except ValueError as parse_ex:
             mdict = {'type': data_type, 'error': six.text_type(parse_ex)}
             msg = _("%(type)s not in valid format: %(error)s") % mdict
@@ -121,7 +115,8 @@ class InstantiationData(object):
         else:
             raise exc.HTTPBadRequest(_("No template specified"))
 
-        return self.format_parse(template_data, 'Template')
+        with self.parse_error_check('Template'):
+            return template_format.parse(template_data)
 
     def environment(self):
         """
@@ -135,8 +130,8 @@ class InstantiationData(object):
             if isinstance(env_data, dict):
                 env = env_data
             else:
-                env = self.format_parse(env_data,
-                                        'Environment')
+                with self.parse_error_check('Environment'):
+                    env = environment_format.parse(env_data)
 
         environment_format.default_for_missing(env)
         parameters = self.data.get(self.PARAM_USER_PARAMS, {})
diff --git a/heat/tests/api/openstack_v1/test_api_openstack_v1.py b/heat/tests/api/openstack_v1/test_api_openstack_v1.py
index 3f2064e226..400d2d1473 100644
--- a/heat/tests/api/openstack_v1/test_api_openstack_v1.py
+++ b/heat/tests/api/openstack_v1/test_api_openstack_v1.py
@@ -34,6 +34,7 @@ import heat.api.openstack.v1.stacks as stacks
 from heat.common import exception as heat_exc
 from heat.common import identifier
 from heat.common import policy
+from heat.common import template_format
 from heat.common import urlfetch
 from heat.common import wsgi
 from heat.rpc import api as rpc_api
@@ -64,22 +65,18 @@ def to_remote_error(error):
 
 class InstantiationDataTest(common.HeatTestCase):
 
-    def test_format_parse(self):
-        data = {"AWSTemplateFormatVersion": "2010-09-09",
-                "key1": ["val1[0]", "val1[1]"],
-                "key2": "val2"}
-        json_repr = ('{"AWSTemplateFormatVersion" : "2010-09-09",'
-                     '"key1": [ "val1[0]", "val1[1]" ], '
-                     '"key2": "val2" }')
-        parsed = stacks.InstantiationData.format_parse(json_repr, 'foo')
-        self.assertEqual(data, parsed)
+    def test_parse_error_success(self):
+        with stacks.InstantiationData.parse_error_check('Garbage'):
+            pass
 
-    def test_format_parse_invalid(self):
-        self.assertRaises(webob.exc.HTTPBadRequest,
-                          stacks.InstantiationData.format_parse,
-                          '!@#$%^&not json', 'Garbage')
+    def test_parse_error(self):
+        def generate_error():
+            with stacks.InstantiationData.parse_error_check('Garbage'):
+                raise ValueError
 
-    def test_format_parse_invalid_message(self):
+        self.assertRaises(webob.exc.HTTPBadRequest, generate_error)
+
+    def test_parse_error_message(self):
         # make sure the parser error gets through to the caller.
         bad_temp = '''
 heat_template_version: '2013-05-23'
@@ -89,10 +86,13 @@ parameters:
     description: bla
         '''
 
-        parse_ex = self.assertRaises(webob.exc.HTTPBadRequest,
-                                     stacks.InstantiationData.format_parse,
-                                     bad_temp, 'foo')
+        def generate_error():
+            with stacks.InstantiationData.parse_error_check('foo'):
+                template_format.parse(bad_temp)
+
+        parse_ex = self.assertRaises(webob.exc.HTTPBadRequest, generate_error)
         self.assertIn('line 4, column 3', six.text_type(parse_ex))
+        self.assertIn('foo', six.text_type(parse_ex))
 
     def test_stack_name(self):
         body = {'stack_name': 'wibble'}