oslo.concurrency/tests/test_watchdog.py
Sean Dague df35680b67 add watchdog module
This provides the watchdog.watch function which is a contextmanager
that can be used before doing operations that have a high risk of
deadlocking or aberrantly taking huge amounts of time to complete
(which could be the root cause for other issues).

Unit tests require the use of sleep to make the timers pop either
before or after the event in question. There is 1 second buffer that's
encoded into each scenario which should be sufficient for unit tests
(even in busy systems). If that turns into an issue later, the buffer
can be increased (I was only seeing real skew of 1-2 ms locally).

Change-Id: I79e39f8a4aa702627ca39bea3e6fc672134b8a72
2015-01-09 15:38:48 -05:00

76 lines
2.7 KiB
Python

# Copyright (c) 2015 Hewlett-Packard Development Company, L.P.
#
# 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 subprocess
import time
import fixtures
from oslotest import base as test_base
from oslo_concurrency import watchdog
LOG_FORMAT = '%(levelname)s %(message)s'
class WatchdogTest(test_base.BaseTestCase):
def setUp(self):
super(WatchdogTest, self).setUp()
# capture the log bits where we can interrogate them
self.logger = logging.getLogger()
self.logger.setLevel(logging.DEBUG)
self.log = self.useFixture(
fixtures.FakeLogger(format=LOG_FORMAT, level=None)
)
def test_in_process_delay(self):
with watchdog.watch(self.logger, "in process", after=1.0):
time.sleep(2)
self.assertIn("DEBUG in process not completed after 1",
self.log.output)
loglines = self.log.output.rstrip().split("\n")
self.assertEqual(1, len(loglines), loglines)
def test_level_setting(self):
with watchdog.watch(self.logger, "in process",
level=logging.ERROR, after=1.0):
time.sleep(2)
self.assertIn("ERROR in process not completed after 1",
self.log.output)
loglines = self.log.output.rstrip().split("\n")
self.assertEqual(1, len(loglines), loglines)
def test_in_process_delay_no_message(self):
with watchdog.watch(self.logger, "in process", after=1.0):
pass
# wait long enough to know there won't be a message emitted
time.sleep(2)
self.assertEqual('', self.log.output)
def test_in_process_exploding(self):
try:
with watchdog.watch(self.logger, "ungraceful exit", after=1.0):
raise Exception()
except Exception:
pass
# wait long enough to know there won't be a message emitted
time.sleep(2)
self.assertEqual('', self.log.output)
def test_subprocess_delay(self):
with watchdog.watch(self.logger, "subprocess", after=0.1):
subprocess.call("sleep 2", shell=True)
self.assertIn("DEBUG subprocess not completed after 0",
self.log.output)