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# Copyright 2015, 2016 IBM Corp.
#
# All Rights Reserved.
#
# 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 mock
import random
import testtools
from pypowervm import adapter as adpt
from pypowervm import const as c
from pypowervm import exceptions as pvm_exc
from pypowervm.utils import retry as pvm_retry
called_count = 0
class TestRetry(testtools.TestCase):
"""Unit tests for pypowervm.util."""
def test_retry(self):
global called_count
# Test normal call with return values
@pvm_retry.retry(tries=4)
def some_method(x, y):
global called_count
called_count += 1
return x, y
called_count = 0
val = some_method(1, 2)
self.assertEqual(val, (1, 2))
self.assertEqual(called_count, 1)
# Test with an unexpected exception
class OurException(Exception):
pass
@pvm_retry.retry(tries=4)
def except_method(x, y):
global called_count
called_count += 1
raise OurException()
called_count = 0
self.assertRaises(OurException, except_method, 1, 2)
self.assertEqual(called_count, 1)
# Test retry with an http code
@pvm_retry.retry(tries=4, http_codes=(c.HTTPStatus.ETAG_MISMATCH,))
def http_except_method(x, y):
global called_count
called_count += 1
resp = adpt.Response('reqmethod', 'reqpath',
c.HTTPStatus.ETAG_MISMATCH, 'reason',
'headers', None)
http_exc = pvm_exc.HttpError(resp)
raise http_exc
called_count = 0
self.assertRaises(pvm_exc.HttpError, http_except_method, 1, 2)
self.assertEqual(called_count, 4)
# Test retry with an test func and custom exception
def cust_test(e, try_, tries, *args, **kwds):
return try_ != 2
@pvm_retry.retry(tries=10, test_func=cust_test,
limit_except=OurException())
def func_except_method(x, y):
global called_count
called_count += 1
resp = adpt.Response('reqmethod', 'reqpath',
c.HTTPStatus.ETAG_MISMATCH, 'reason',
'headers', None)
http_exc = pvm_exc.HttpError(resp)
raise http_exc
called_count = 0
# Should get back OurException after just 2 calls
self.assertRaises(OurException, func_except_method, 1, 2)
self.assertEqual(called_count, 2)
# Test custom exceptions to retry
@pvm_retry.retry(tries=3, retry_except=OurException)
def func_except_method(x, y):
global called_count
called_count += 1
raise OurException()
called_count = 0
# Should get back OurException after just 3 calls
with self.assertLogs(pvm_retry.__name__, 'WARNING') as warn_logs:
self.assertRaises(OurException, func_except_method, 1, 2)
self.assertEqual(2, len(warn_logs.output))
self.assertEqual(called_count, 3)
# Test the response checking function
def resp_chkr(resp, try_, tries, *args, **kwds):
if try_ == 2:
raise OurException()
# Tell it to retry
return True
@pvm_retry.retry(tries=10, resp_checker=resp_chkr)
def func_resp_chkr(x, y):
global called_count
called_count += 1
return x, y
called_count = 0
# Should get back OurException after just 2 calls
self.assertRaises(OurException, func_resp_chkr, 1, 2)
self.assertEqual(called_count, 2)
def test_retry_example(self):
global called_count
called_count = 0
def _resp_checker(resp, try_, _tries, *args, **kwds):
# If the VIOS is busy, then retry
return resp == 'VIOS IS BUSY'
@pvm_retry.retry(tries=4, http_codes=pvm_retry.DFT_RETRY_CODES,
resp_checker=_resp_checker)
def _powervm_update(parm):
global called_count
called_count += 1
if called_count == 1:
# etag mismatch
resp = adpt.Response('reqmethod', 'reqpath',
c.HTTPStatus.ETAG_MISMATCH, 'reason',
'headers')
http_exc = pvm_exc.HttpError(resp)
raise http_exc
if called_count == 2:
# Pretend we got a valid response, but the VIOS is busy
return 'VIOS IS BUSY'
if called_count == 3:
# Pretend we got a good response
return parm
return None
with self.assertLogs(pvm_retry.__name__, 'WARNING') as warn_logs:
self.assertEqual(_powervm_update('Req'), 'Req')
# only one warning (etag mismatch). The 'VIOS IS BUSY' is
# returned as OK by the _resp_checker, but doesn't do its own
# logging
self.assertEqual(1, len(warn_logs.output))
self.assertEqual(called_count, 3)
def test_retry_argmod(self):
global called_count
called_count = 0
def argmod_func(this_try, max_tries, *args, **kwargs):
argl = list(args)
if this_try == 1:
argl[0] += 1
kwargs['five'] += ' bar'
if this_try == 2:
kwargs['seven'] = 7
return argl, kwargs
@pvm_retry.retry(argmod_func=argmod_func,
resp_checker=lambda *a, **kwa: True)
def _func(one, two, three='four', five='six', seven=None):
global called_count
called_count += 1
self.assertEqual(20, two)
self.assertEqual('four', three)
if called_count == 1:
self.assertEqual(10, one)
self.assertEqual('foo', five)
self.assertIsNone(seven)
else:
self.assertEqual(11, one)
if called_count == 2:
self.assertEqual('foo bar', five)
elif called_count == 3:
self.assertEqual(7, seven)
self.assertEqual('foo bar bar', five)
_func(10, 20, five='foo')
self.assertEqual(3, called_count)
def test_retry_refresh_wrapper(self):
"""Test @retry with the 'refresh_wrapper' argmod_func."""
global called_count
called_count = 0
mock_wrapper = mock.Mock()
mock_wrapper.refreshes = 0
def _refresh(**kwargs):
mock_wrapper.refreshes += 1
self.assertIn('use_etag', kwargs)
self.assertFalse(kwargs['use_etag'])
return mock_wrapper
mock_wrapper.refresh.side_effect = _refresh
@pvm_retry.retry(argmod_func=pvm_retry.refresh_wrapper,
resp_checker=lambda *a, **k: True)
def _func(wrapper, arg1, arg2, kw0=None, kw1=None):
global called_count
self.assertEqual(called_count, wrapper.refreshes)
# Ensure the other args didn't change
self.assertEqual('a1', arg1)
self.assertEqual('a2', arg2)
self.assertEqual('k0', kw0)
self.assertEqual('k1', kw1)
called_count += 1
_func(mock_wrapper, 'a1', 'a2', kw0='k0', kw1='k1')
# Three calls (overall attempts)
self.assertEqual(3, called_count)
# ...equals two refreshes
self.assertEqual(2, mock_wrapper.refreshes)
@mock.patch('time.sleep')
def test_stepped_delay(self, mock_sleep):
# Last set of delays should hit the cap.
delays = [0, .5, 2.0, 6.5, 20.0, 30.0, 30.0]
for i in range(1, 7):
pvm_retry.STEPPED_DELAY(i, 7)
mock_sleep.assert_called_once_with(delays[i-1])
mock_sleep.reset_mock()
@mock.patch('time.sleep')
def test_random_delay(self, mock_sleep):
"""Test gen_random_delay."""
def _validate_range(start, end):
# Sleep was called once.
self.assertEqual(1, mock_sleep.call_count)
args, kwargs = mock_sleep.call_args
# Called with one arg
self.assertEqual(1, len(args))
# ...and no kwargs
self.assertEqual({}, kwargs)
# Extract the arg
slept_with = args[0]
# It should be at least 'start'
self.assertGreaterEqual(slept_with, start)
# ...and at most 'end'.
self.assertLessEqual(slept_with, end)
mock_sleep.reset_mock()
# Defaults
pvm_retry.gen_random_delay()(1, 1)
_validate_range(0, 10)
# Use a randomizer to test a randomizer. It's... poetry.
min_s = random.random() * random.randint(1, 100)
max_s = min_s * random.randint(1, 100)
pvm_retry.gen_random_delay(min_s=min_s, max_s=max_s)(1, 1)
_validate_range(min_s, max_s)
def _validate_stepped_random_range(self, mock_sleep, attempt, start, end,
max_attempts=6):
pvm_retry.STEPPED_RANDOM_DELAY(attempt, max_attempts)
# Sleep was called once.
self.assertEqual(1, mock_sleep.call_count)
args, kwargs = mock_sleep.call_args
# Called with one arg
self.assertEqual(1, len(args))
# ...and no kwargs
self.assertEqual({}, kwargs)
# Extract the arg
slept_with = args[0]
# It should be at least 'start'
self.assertGreaterEqual(slept_with, start)
# ...and at most 'end'.
self.assertLessEqual(slept_with, end)
mock_sleep.reset_mock()
@mock.patch('time.sleep')
def test_stepped_random_delay(self, mock_sleep):
"""Test STEPPED_RANDOM_DELAY."""
# These ranges from RANDOM_DELAY_STEPS
self._validate_stepped_random_range(mock_sleep, 1, 0, 0)
self._validate_stepped_random_range(mock_sleep, 2, 0, 1)
self._validate_stepped_random_range(mock_sleep, 3, 0.5, 4)
self._validate_stepped_random_range(mock_sleep, 4, 2, 13)
self._validate_stepped_random_range(mock_sleep, 5, 6.5, 30)
# Use a range beyond the max attempts. Make sure it does not fail.
for att in (6, 7, 8, 9, 10):
self._validate_stepped_random_range(mock_sleep, att, 0, 60)
@mock.patch('time.sleep')
def test_stepped_random_delay_large(self, mock_sleep):
"""Test STEPPED_RANDOM_DELAY with a very large range."""
max_attempts = 60
# These ranges from RANDOM_DELAY_STEPS
for i in range(1, 10):
self._validate_stepped_random_range(mock_sleep, i, 0, 0,
max_attempts=max_attempts)
for i in range(11, 20):
self._validate_stepped_random_range(mock_sleep, i, 0, 1,
max_attempts=max_attempts)
for i in range(21, 30):
self._validate_stepped_random_range(mock_sleep, i, 0.5, 4,
max_attempts=max_attempts)
for i in range(31, 40):
self._validate_stepped_random_range(mock_sleep, i, 2, 13,
max_attempts=max_attempts)
for i in range(41, 50):
self._validate_stepped_random_range(mock_sleep, i, 6.5, 30,
max_attempts=max_attempts)
for i in range(51, 60):
self._validate_stepped_random_range(mock_sleep, i, 0, 60,
max_attempts=max_attempts)
@mock.patch('time.sleep')
def test_stepped_random_delay_small(self, mock_sleep):
"""Test STEPPED_RANDOM_DELAY with a very small range.
Uses a 'max_attempts' whose range is less than the size of
RANDOM_DELAY_STEPS
"""
# Run this a few times so as to make sure the ranges are fully
# adhered to.
i = 0
while i < 50:
i += 1
self._validate_stepped_random_range(mock_sleep, 1, 0, 0,
max_attempts=3)
self._validate_stepped_random_range(mock_sleep, 2, .5, 4,
max_attempts=3)
self._validate_stepped_random_range(mock_sleep, 3, 6.5, 60,
max_attempts=3)
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