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# Copyright 2020-present MongoDB, 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.
"""Test the topology module's Server Selection Spec implementation."""
from __future__ import annotations
import asyncio
import os
import threading
from pathlib import Path
from test.asynchronous import AsyncIntegrationTest, async_client_context, unittest
from test.asynchronous.helpers import ConcurrentRunner
from test.asynchronous.utils import flaky
from test.asynchronous.utils_selection_tests import create_topology
from test.asynchronous.utils_spec_runner import AsyncSpecTestCreator
from test.utils_shared import (
CMAPListener,
OvertCommandListener,
async_wait_until,
)
from pymongo.common import clean_node
from pymongo.monitoring import ConnectionReadyEvent
from pymongo.operations import _Op
from pymongo.read_preferences import ReadPreference
_IS_SYNC = False
# Location of JSON test specifications.
if _IS_SYNC:
TEST_PATH = os.path.join(Path(__file__).resolve().parent, "server_selection", "in_window")
else:
TEST_PATH = os.path.join(
Path(__file__).resolve().parent.parent, "server_selection", "in_window"
)
class TestAllScenarios(unittest.IsolatedAsyncioTestCase):
async def run_scenario(self, scenario_def):
topology = await create_topology(scenario_def)
# Update mock operation_count state:
for mock in scenario_def["mocked_topology_state"]:
address = clean_node(mock["address"])
server = topology.get_server_by_address(address)
server.pool.operation_count = mock["operation_count"]
pref = ReadPreference.NEAREST
counts = {address: 0 for address in topology._description.server_descriptions()}
# Number of times to repeat server selection
iterations = scenario_def["iterations"]
for _ in range(iterations):
server = await topology.select_server(pref, _Op.TEST, server_selection_timeout=0)
counts[server.description.address] += 1
# Verify expected_frequencies
outcome = scenario_def["outcome"]
tolerance = outcome["tolerance"]
expected_frequencies = outcome["expected_frequencies"]
for host_str, freq in expected_frequencies.items():
address = clean_node(host_str)
actual_freq = float(counts[address]) / iterations
if freq == 0:
# Should be exactly 0.
self.assertEqual(actual_freq, 0)
else:
# Should be within 'tolerance'.
self.assertAlmostEqual(actual_freq, freq, delta=tolerance)
def create_test(scenario_def, test, name):
async def run_scenario(self):
await self.run_scenario(scenario_def)
return run_scenario
class CustomSpecTestCreator(AsyncSpecTestCreator):
def tests(self, scenario_def):
"""Extract the tests from a spec file.
Server selection in_window tests do not have a 'tests' field.
The whole file represents a single test case.
"""
return [scenario_def]
CustomSpecTestCreator(create_test, TestAllScenarios, TEST_PATH).create_tests()
class FinderTask(ConcurrentRunner):
def __init__(self, collection, iterations):
super().__init__()
self.daemon = True
self.collection = collection
self.iterations = iterations
self.passed = False
async def run(self):
for _ in range(self.iterations):
await self.collection.find_one({})
self.passed = True
class TestProse(AsyncIntegrationTest):
async def frequencies(self, client, listener, n_finds=10):
coll = client.test.test
N_TASKS = 10
tasks = [FinderTask(coll, n_finds) for _ in range(N_TASKS)]
for task in tasks:
await task.start()
for task in tasks:
await task.join()
for task in tasks:
self.assertTrue(task.passed)
events = listener.started_events
self.assertEqual(len(events), n_finds * N_TASKS)
nodes = client.nodes
self.assertEqual(len(nodes), 2)
freqs = {address: 0.0 for address in nodes}
for event in events:
freqs[event.connection_id] += 1
for address in freqs:
freqs[address] = freqs[address] / float(len(events))
return freqs
@async_client_context.require_failCommand_appName
@async_client_context.require_multiple_mongoses
@flaky(reason="PYTHON-3689")
async def test_load_balancing(self):
listener = OvertCommandListener()
cmap_listener = CMAPListener()
# PYTHON-2584: Use a large localThresholdMS to avoid the impact of
# varying RTTs.
client = await self.async_rs_client(
async_client_context.mongos_seeds(),
appName="loadBalancingTest",
event_listeners=[listener, cmap_listener],
localThresholdMS=30000,
minPoolSize=10,
)
await async_wait_until(lambda: len(client.nodes) == 2, "discover both nodes")
# Wait for both pools to be populated.
await cmap_listener.async_wait_for_event(ConnectionReadyEvent, 20)
# Delay find commands on only one mongos.
delay_finds = {
"configureFailPoint": "failCommand",
"mode": {"times": 10000},
"data": {
"failCommands": ["find"],
"blockConnection": True,
"blockTimeMS": 500,
"appName": "loadBalancingTest",
},
}
async with self.fail_point(delay_finds):
nodes = async_client_context.client.nodes
self.assertEqual(len(nodes), 1)
delayed_server = next(iter(nodes))
freqs = await self.frequencies(client, listener)
self.assertLessEqual(freqs[delayed_server], 0.25)
listener.reset()
freqs = await self.frequencies(client, listener, n_finds=150)
self.assertAlmostEqual(freqs[delayed_server], 0.50, delta=0.15)
if __name__ == "__main__":
unittest.main()
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