From 099108aab37d1fae1b27f4e2e20136c234df1a52 Mon Sep 17 00:00:00 2001 From: Rodolfo Alonso Hernandez Date: Thu, 19 Apr 2018 14:58:38 +0100 Subject: Add active wait function Added function "wait_until_true". This function will make an active wait until the predicate passed as an argument returns True. If the timeout expires, the function will raise a generic exception or a user defined one passed as an argument. This function will be used in YARDSTICK-1127. JIRA: YARDSTICK-1128 Change-Id: I9854e465ac6b586bf4be39ab4b266d5625b39e30 Signed-off-by: Rodolfo Alonso Hernandez --- yardstick/common/exceptions.py | 8 ++++++ yardstick/common/utils.py | 34 +++++++++++++++++++++++- yardstick/tests/unit/common/test_utils.py | 44 ++++++++++++++++++++++++++++++- 3 files changed, 84 insertions(+), 2 deletions(-) diff --git a/yardstick/common/exceptions.py b/yardstick/common/exceptions.py index bc16cab8f..330eb5e0a 100644 --- a/yardstick/common/exceptions.py +++ b/yardstick/common/exceptions.py @@ -148,6 +148,14 @@ class TaskRenderError(YardstickException): message = 'Failed to render template:\n%(input_task)s' +class TimerTimeout(YardstickException): + message = 'Timer timeout expired, %(timeout)s seconds' + + +class WaitTimeout(YardstickException): + message = 'Wait timeout while waiting for condition' + + class ScenarioCreateNetworkError(YardstickException): message = 'Create Neutron Network Scenario failed' diff --git a/yardstick/common/utils.py b/yardstick/common/utils.py index 44cc92a7c..108ee17bc 100644 --- a/yardstick/common/utils.py +++ b/yardstick/common/utils.py @@ -23,9 +23,11 @@ import logging import os import random import re +import signal import socket import subprocess import sys +import time import six from flask import jsonify @@ -34,6 +36,8 @@ from oslo_serialization import jsonutils from oslo_utils import encodeutils import yardstick +from yardstick.common import exceptions + logger = logging.getLogger(__name__) logger.setLevel(logging.DEBUG) @@ -405,15 +409,24 @@ class ErrorClass(object): class Timer(object): - def __init__(self): + def __init__(self, timeout=None): super(Timer, self).__init__() self.start = self.delta = None + self._timeout = int(timeout) if timeout else None + + def _timeout_handler(self, *args): + raise exceptions.TimerTimeout(timeout=self._timeout) def __enter__(self): self.start = datetime.datetime.now() + if self._timeout: + signal.signal(signal.SIGALRM, self._timeout_handler) + signal.alarm(self._timeout) return self def __exit__(self, *_): + if self._timeout: + signal.alarm(0) self.delta = datetime.datetime.now() - self.start def __getattr__(self, item): @@ -460,3 +473,22 @@ def open_relative_file(path, task_path): if e.errno == errno.ENOENT: return open(os.path.join(task_path, path)) raise + + +def wait_until_true(predicate, timeout=60, sleep=1, exception=None): + """Wait until callable predicate is evaluated as True + + :param predicate: (func) callable deciding whether waiting should continue + :param timeout: (int) timeout in seconds how long should function wait + :param sleep: (int) polling interval for results in seconds + :param exception: exception instance to raise on timeout. If None is passed + (default) then WaitTimeout exception is raised. + """ + try: + with Timer(timeout=timeout): + while not predicate(): + time.sleep(sleep) + except exceptions.TimerTimeout: + if exception and issubclass(exception, Exception): + raise exception # pylint: disable=raising-bad-type + raise exceptions.WaitTimeout diff --git a/yardstick/tests/unit/common/test_utils.py b/yardstick/tests/unit/common/test_utils.py index 9540a39e8..666b29b5f 100644 --- a/yardstick/tests/unit/common/test_utils.py +++ b/yardstick/tests/unit/common/test_utils.py @@ -16,13 +16,15 @@ import mock import os import six from six.moves import configparser +import time import unittest import yardstick from yardstick import ssh import yardstick.error -from yardstick.common import utils from yardstick.common import constants +from yardstick.common import utils +from yardstick.common import exceptions class IterSubclassesTestCase(unittest.TestCase): @@ -1158,3 +1160,43 @@ class ReadMeminfoTestCase(unittest.TestCase): output = utils.read_meminfo(ssh_client) mock_get_client.assert_called_once_with('/proc/meminfo', mock.ANY) self.assertEqual(self.MEMINFO_DICT, output) + + +class TimerTestCase(unittest.TestCase): + + def test__getattr(self): + with utils.Timer() as timer: + time.sleep(1) + self.assertEqual(1, round(timer.total_seconds(), 0)) + self.assertEqual(1, timer.delta.seconds) + + def test__enter_with_timeout(self): + with utils.Timer(timeout=10) as timer: + time.sleep(1) + self.assertEqual(1, round(timer.total_seconds(), 0)) + + def test__enter_with_timeout_exception(self): + with self.assertRaises(exceptions.TimerTimeout): + with utils.Timer(timeout=1): + time.sleep(2) + + +class WaitUntilTrueTestCase(unittest.TestCase): + + def test_no_timeout(self): + self.assertIsNone(utils.wait_until_true(lambda: True, + timeout=1, sleep=1)) + + def test_timeout_generic_exception(self): + with self.assertRaises(exceptions.WaitTimeout): + self.assertIsNone(utils.wait_until_true(lambda: False, + timeout=1, sleep=1)) + + def test_timeout_given_exception(self): + class MyTimeoutException(exceptions.YardstickException): + message = 'My timeout exception' + + with self.assertRaises(MyTimeoutException): + self.assertIsNone( + utils.wait_until_true(lambda: False, timeout=1, sleep=1, + exception=MyTimeoutException)) -- cgit 1.2.3-korg