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# Copyright 2017 Amazon.com, Inc. or its affiliates. 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. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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 contextlib
import json
from tests import BaseSessionTest, mock, ClientHTTPStubber
from botocore.exceptions import ClientError
from botocore.config import Config
class BaseRetryTest(BaseSessionTest):
def setUp(self):
super(BaseRetryTest, self).setUp()
self.region = 'us-west-2'
self.sleep_patch = mock.patch('time.sleep')
self.sleep_patch.start()
def tearDown(self):
super(BaseRetryTest, self).tearDown()
self.sleep_patch.stop()
@contextlib.contextmanager
def assert_will_retry_n_times(self, client, num_retries,
status=500, body=b'{}'):
num_responses = num_retries + 1
if not isinstance(body, bytes):
body = json.dumps(body).encode()
with ClientHTTPStubber(client) as http_stubber:
for _ in range(num_responses):
http_stubber.add_response(status=status, body=body)
with self.assertRaisesRegexp(
ClientError, 'reached max retries: %s' % num_retries):
yield
self.assertEqual(len(http_stubber.requests), num_responses)
class TestLegacyRetry(BaseRetryTest):
def test_can_override_max_attempts(self):
client = self.session.create_client(
'dynamodb', self.region, config=Config(
retries={'max_attempts': 1}))
with self.assert_will_retry_n_times(client, 1):
client.list_tables()
def test_do_not_attempt_retries(self):
client = self.session.create_client(
'dynamodb', self.region, config=Config(
retries={'max_attempts': 0}))
with self.assert_will_retry_n_times(client, 0):
client.list_tables()
def test_setting_max_attempts_does_not_set_for_other_clients(self):
# Make one client with max attempts configured.
self.session.create_client(
'codecommit', self.region, config=Config(
retries={'max_attempts': 1}))
# Make another client that has no custom retry configured.
client = self.session.create_client('codecommit', self.region)
# It should use the default max retries, which should be four retries
# for this service.
with self.assert_will_retry_n_times(client, 4):
client.list_repositories()
def test_service_specific_defaults_do_not_mutate_general_defaults(self):
# This tests for a bug where if you created a client for a service
# with specific retry configurations and then created a client for
# a service whose retry configurations fallback to the general
# defaults, the second client would actually use the defaults of
# the first client.
# Make a dynamodb client. It's a special case client that is
# configured to a make a maximum of 10 requests (9 retries).
client = self.session.create_client('dynamodb', self.region)
with self.assert_will_retry_n_times(client, 9):
client.list_tables()
# A codecommit client is not a special case for retries. It will at
# most make 5 requests (4 retries) for its default.
client = self.session.create_client('codecommit', self.region)
with self.assert_will_retry_n_times(client, 4):
client.list_repositories()
def test_set_max_attempts_on_session(self):
self.session.set_default_client_config(
Config(retries={'max_attempts': 1}))
# Max attempts should be inherited from the session.
client = self.session.create_client('codecommit', self.region)
with self.assert_will_retry_n_times(client, 1):
client.list_repositories()
def test_can_clobber_max_attempts_on_session(self):
self.session.set_default_client_config(
Config(retries={'max_attempts': 1}))
# Max attempts should override the session's configured max attempts.
client = self.session.create_client(
'codecommit', self.region, config=Config(
retries={'max_attempts': 0}))
with self.assert_will_retry_n_times(client, 0):
client.list_repositories()
class TestRetriesV2(BaseRetryTest):
def create_client_with_retry_mode(self, service, retry_mode,
max_attempts=None):
retries = {'mode': retry_mode}
if max_attempts is not None:
retries['total_max_attempts'] = max_attempts
client = self.session.create_client(
service, self.region, config=Config(retries=retries))
return client
def test_standard_mode_has_default_3_retries(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard')
with self.assert_will_retry_n_times(client, 2):
client.list_tables()
def test_standard_mode_can_configure_max_attempts(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard', max_attempts=5)
with self.assert_will_retry_n_times(client, 4):
client.list_tables()
def test_no_retry_needed_standard_mode(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard')
with ClientHTTPStubber(client) as http_stubber:
http_stubber.add_response(status=200, body=b'{}')
client.list_tables()
def test_standard_mode_retry_throttling_error(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard')
error_body = {
"__type": "ThrottlingException",
"message": "Error"
}
with self.assert_will_retry_n_times(client, 2,
status=400,
body=error_body):
client.list_tables()
def test_standard_mode_retry_transient_error(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard')
with self.assert_will_retry_n_times(client, 2, status=502):
client.list_tables()
def test_adaptive_mode_still_retries_errors(self):
# Verify that adaptive mode is just adding on to standard mode.
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='adaptive')
with self.assert_will_retry_n_times(client, 2):
client.list_tables()
def test_adaptive_mode_retry_transient_error(self):
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='adaptive')
with self.assert_will_retry_n_times(client, 2, status=502):
client.list_tables()
def test_can_exhaust_default_retry_quota(self):
# Quota of 500 / 5 retry costs == 100 retry attempts
# 100 retry attempts / 2 retries per API call == 50 client calls
client = self.create_client_with_retry_mode(
'dynamodb', retry_mode='standard')
for i in range(50):
with self.assert_will_retry_n_times(client, 2, status=502):
client.list_tables()
# Now on the 51th attempt we should see quota errors, which we can
# verify by looking at the request metadata.
with ClientHTTPStubber(client) as http_stubber:
http_stubber.add_response(status=502, body=b'{}')
with self.assertRaises(ClientError) as e:
client.list_tables()
self.assertTrue(
e.exception.response['ResponseMetadata'].get('RetryQuotaReached')
)
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