oslo.utils/oslo_utils/tests/test_excutils.py
Joshua Harlow eba46f3a8e Provide a common exception caused by base class
Both taskflow and tooz (and others of `raise_with_cause`
should be able to use this as there base exception class
to ensure that there usage of `raise_with_cause` works
as expected).

This adds the class that taskflow was/is using that provides
a 'good enough' version exception chaining (and a decently useful
`pformat` and `__str__` overrides that approximates the exception
chaining message on py2.x).

When used correctly this produces the following:

http://paste.openstack.org/show/326021/

Which is a 'good enough' approximation of exception chaining
on py2.x (and just uses the native exception chaining on py3.x)

This also adds some basic tests to ensure the functionality
provided continues to work as expected.

Change-Id: If814816dec91f7da3c90f4b9b8e2d3cf7228b928
2015-08-04 15:49:21 -07:00

245 lines
9.1 KiB
Python

# Copyright 2012, Red Hat, Inc.
#
# 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 logging
import time
import mock
from oslotest import base as test_base
from oslotest import moxstubout
from oslo_utils import excutils
mox = moxstubout.mox
class Fail1(excutils.CausedByException):
pass
class Fail2(excutils.CausedByException):
pass
class CausedByTest(test_base.BaseTestCase):
def test_caused_by_explicit(self):
e = self.assertRaises(Fail1,
excutils.raise_with_cause,
Fail1, "I was broken",
cause=Fail2("I have been broken"))
self.assertIsInstance(e.cause, Fail2)
e_p = e.pformat()
self.assertIn("I have been broken", e_p)
self.assertIn("Fail2", e_p)
def test_caused_by_implicit(self):
def raises_chained():
try:
raise Fail2("I have been broken")
except Fail2:
excutils.raise_with_cause(Fail1, "I was broken")
e = self.assertRaises(Fail1, raises_chained)
self.assertIsInstance(e.cause, Fail2)
e_p = e.pformat()
self.assertIn("I have been broken", e_p)
self.assertIn("Fail2", e_p)
class SaveAndReraiseTest(test_base.BaseTestCase):
def test_save_and_reraise_exception(self):
e = None
msg = 'foo'
try:
try:
raise Exception(msg)
except Exception:
with excutils.save_and_reraise_exception():
pass
except Exception as _e:
e = _e
self.assertEqual(str(e), msg)
@mock.patch('logging.getLogger')
def test_save_and_reraise_exception_dropped(self, get_logger_mock):
logger = get_logger_mock()
e = None
msg = 'second exception'
try:
try:
raise Exception('dropped')
except Exception:
with excutils.save_and_reraise_exception():
raise Exception(msg)
except Exception as _e:
e = _e
self.assertEqual(str(e), msg)
self.assertTrue(logger.error.called)
def test_save_and_reraise_exception_no_reraise(self):
"""Test that suppressing the reraise works."""
try:
raise Exception('foo')
except Exception:
with excutils.save_and_reraise_exception() as ctxt:
ctxt.reraise = False
@mock.patch('logging.getLogger')
def test_save_and_reraise_exception_dropped_no_reraise(self,
get_logger_mock):
logger = get_logger_mock()
e = None
msg = 'second exception'
try:
try:
raise Exception('dropped')
except Exception:
with excutils.save_and_reraise_exception(reraise=False):
raise Exception(msg)
except Exception as _e:
e = _e
self.assertEqual(str(e), msg)
self.assertFalse(logger.error.called)
def test_save_and_reraise_exception_provided_logger(self):
fake_logger = mock.MagicMock()
try:
try:
raise Exception('foo')
except Exception:
with excutils.save_and_reraise_exception(logger=fake_logger):
raise Exception('second exception')
except Exception:
pass
self.assertTrue(fake_logger.error.called)
class ForeverRetryUncaughtExceptionsTest(test_base.BaseTestCase):
def setUp(self):
super(ForeverRetryUncaughtExceptionsTest, self).setUp()
moxfixture = self.useFixture(moxstubout.MoxStubout())
self.mox = moxfixture.mox
self.stubs = moxfixture.stubs
@excutils.forever_retry_uncaught_exceptions
def exception_generator(self):
exc = self.exception_to_raise()
while exc is not None:
raise exc
exc = self.exception_to_raise()
def exception_to_raise(self):
return None
def my_time_sleep(self, arg):
pass
def exc_retrier_common_start(self):
self.stubs.Set(time, 'sleep', self.my_time_sleep)
self.mox.StubOutWithMock(logging, 'exception')
self.mox.StubOutWithMock(time, 'time',
use_mock_anything=True)
self.mox.StubOutWithMock(self, 'exception_to_raise')
def exc_retrier_sequence(self, exc_id=None, timestamp=None,
exc_count=None):
self.exception_to_raise().AndReturn(
Exception('unexpected %d' % exc_id))
time.time().AndReturn(timestamp)
if exc_count != 0:
logging.exception(mox.In(
'Unexpected exception occurred %d time(s)' % exc_count))
def exc_retrier_common_end(self):
self.exception_to_raise().AndReturn(None)
self.mox.ReplayAll()
self.exception_generator()
self.addCleanup(self.stubs.UnsetAll)
def test_exc_retrier_1exc_gives_1log(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
self.exc_retrier_common_end()
def test_exc_retrier_same_10exc_1min_gives_1log(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
# By design, the following exception don't get logged because they
# are within the same minute.
for i in range(2, 11):
self.exc_retrier_sequence(exc_id=1, timestamp=i, exc_count=0)
self.exc_retrier_common_end()
def test_exc_retrier_same_2exc_2min_gives_2logs(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
self.exc_retrier_sequence(exc_id=1, timestamp=65, exc_count=1)
self.exc_retrier_common_end()
def test_exc_retrier_same_10exc_2min_gives_2logs(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
self.exc_retrier_sequence(exc_id=1, timestamp=12, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=23, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=34, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=45, exc_count=0)
# The previous 4 exceptions are counted here
self.exc_retrier_sequence(exc_id=1, timestamp=106, exc_count=5)
# Again, the following are not logged due to being within
# the same minute
self.exc_retrier_sequence(exc_id=1, timestamp=117, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=128, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=139, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=150, exc_count=0)
self.exc_retrier_common_end()
def test_exc_retrier_mixed_4exc_1min_gives_2logs(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
# By design, this second 'unexpected 1' exception is not counted. This
# is likely a rare thing and is a sacrifice for code simplicity.
self.exc_retrier_sequence(exc_id=1, timestamp=10, exc_count=0)
self.exc_retrier_sequence(exc_id=2, timestamp=20, exc_count=1)
# Again, trailing exceptions within a minute are not counted.
self.exc_retrier_sequence(exc_id=2, timestamp=30, exc_count=0)
self.exc_retrier_common_end()
def test_exc_retrier_mixed_4exc_2min_gives_2logs(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
# Again, this second exception of the same type is not counted
# for the sake of code simplicity.
self.exc_retrier_sequence(exc_id=1, timestamp=10, exc_count=0)
# The difference between this and the previous case is the log
# is also triggered by more than a minute expiring.
self.exc_retrier_sequence(exc_id=2, timestamp=100, exc_count=1)
self.exc_retrier_sequence(exc_id=2, timestamp=110, exc_count=0)
self.exc_retrier_common_end()
def test_exc_retrier_mixed_4exc_2min_gives_3logs(self):
self.exc_retrier_common_start()
self.exc_retrier_sequence(exc_id=1, timestamp=1, exc_count=1)
# This time the second 'unexpected 1' exception is counted due
# to the same exception occurring same when the minute expires.
self.exc_retrier_sequence(exc_id=1, timestamp=10, exc_count=0)
self.exc_retrier_sequence(exc_id=1, timestamp=100, exc_count=2)
self.exc_retrier_sequence(exc_id=2, timestamp=110, exc_count=1)
self.exc_retrier_common_end()