Create wrapper to sys.exc_info

try:
     ...
 except SomeException:
     with tobiko.exc_info():
         # It will reraise original exception at the end of this block
         ...

Change-Id: Icad6bdd7261dd9b972b5b33110041876ca488070

tobiko/__init__.py

@@ -26,6 +26,7 @@ fail = _asserts.fail
 
 TobikoException = _exception.TobikoException
 check_valid_type = _exception.check_valid_type
+exc_info = _exception.exc_info
 
 is_fixture = _fixture.is_fixture
 get_fixture = _fixture.get_fixture

tobiko/common/_exception.py

@@ -13,6 +13,15 @@
 #    under the License.
 from __future__ import absolute_import
 
+import collections
+import sys
+
+from oslo_log import log
+import six
+
+
+LOG = log.getLogger(__name__)
+
 
 class TobikoException(Exception):
     """Base Tobiko Exception.
@@ -72,3 +81,27 @@ def check_valid_type(obj, *valid_types):
             obj, types_str)
         raise TypeError(message)
     return obj
+
+
+class ExceptionInfo(collections.namedtuple('ExceptionInfo',
+                                           ['type', 'value', 'traceback'])):
+
+    reraise_on_exit = True
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, _type, _value, _traceback):
+        if self.reraise_on_exit:
+            LOG.exception("Exception occurred while handling %s(%s) "
+                          "exception.", _type, _value)
+            self.reraise()
+
+    def reraise(self):
+        six.reraise(*self)
+
+
+def exc_info(reraise=True):
+    info = ExceptionInfo(*sys.exc_info())
+    info.reraise_on_exit = reraise
+    return info

tobiko/common/managers/ansible.py

@@ -82,7 +82,7 @@ class AnsibleManager(object):
                       'username': credentials.username,
                       'project_name': credentials.project_name,
                       'password': credentials.project_name.password,
-                      'image': CONF.tobiko.nova.image,
+                      'image': CONF.tobiko.glance.cirros_image,
                       'flavor': CONF.tobiko.nova.flavor}
 
         self.variable_manager.extra_vars = extra_vars

tobiko/tests/unit/test_exception.py

@@ -13,6 +13,8 @@
 #    under the License.
 from __future__ import absolute_import
 
+import sys
+
 import tobiko
 from tobiko.tests import unit
 
@@ -102,3 +104,21 @@ class TestCheckValidType(unit.TobikoUnitTest):
                    ).format(repr(obj), tyes_str)
 
         self.assertEqual(message, str(ex))
+
+
+class TestExcInfo(unit.TobikoUnitTest):
+
+    def test_exc_info(self):
+        try:
+            raise RuntimeError('some error')
+        except RuntimeError:
+            exc_info = tobiko.exc_info()
+            exc_type, exc_value, traceback = sys.exc_info()
+
+        self.assertEqual((exc_type, exc_value, traceback), exc_info)
+        self.assertIs(RuntimeError, exc_info.type)
+        self.assertIs(exc_value, exc_info.value)
+        self.assertIs(traceback, exc_info.traceback)
+
+        reraised = self.assertRaises(RuntimeError, exc_info.reraise)
+        self.assertIs(exc_value, reraised)