mongo-python-driver/test/test_server_selection.py
Noah Stapp a1ade45dd3
PYTHON-4881 - Use OvertCommandListener wherever sensitive events are not needed (#1943)
Co-authored-by: Steven Silvester <steven.silvester@ieee.org>
2024-10-18 13:32:09 -04:00

205 lines
8.1 KiB
Python

# Copyright 2015-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 os
import sys
from pymongo import MongoClient, ReadPreference
from pymongo.errors import ServerSelectionTimeoutError
from pymongo.hello import HelloCompat
from pymongo.operations import _Op
from pymongo.server_selectors import writable_server_selector
from pymongo.synchronous.settings import TopologySettings
from pymongo.synchronous.topology import Topology
from pymongo.typings import strip_optional
sys.path[0:0] = [""]
from test import IntegrationTest, client_context, unittest
from test.utils import (
EventListener,
FunctionCallRecorder,
OvertCommandListener,
wait_until,
)
from test.utils_selection_tests import (
create_selection_tests,
get_addresses,
get_topology_settings_dict,
make_server_description,
)
# Location of JSON test specifications.
_TEST_PATH = os.path.join(
os.path.dirname(os.path.realpath(__file__)),
os.path.join("server_selection", "server_selection"),
)
class SelectionStoreSelector:
"""No-op selector that keeps track of what was passed to it."""
def __init__(self):
self.selection = None
def __call__(self, selection):
self.selection = selection
return selection
class TestAllScenarios(create_selection_tests(_TEST_PATH)): # type: ignore
pass
class TestCustomServerSelectorFunction(IntegrationTest):
@client_context.require_replica_set
def test_functional_select_max_port_number_host(self):
# Selector that returns server with highest port number.
def custom_selector(servers):
ports = [s.address[1] for s in servers]
idx = ports.index(max(ports))
return [servers[idx]]
# Initialize client with appropriate listeners.
listener = OvertCommandListener()
client = self.rs_or_single_client(
server_selector=custom_selector, event_listeners=[listener]
)
self.addCleanup(client.close)
coll = client.get_database("testdb", read_preference=ReadPreference.NEAREST).coll
self.addCleanup(client.drop_database, "testdb")
# Wait the node list to be fully populated.
def all_hosts_started():
return len(client.admin.command(HelloCompat.LEGACY_CMD)["hosts"]) == len(
client._topology._description.readable_servers
)
wait_until(all_hosts_started, "receive heartbeat from all hosts")
expected_port = max(
[strip_optional(n.address[1]) for n in client._topology._description.readable_servers]
)
# Insert 1 record and access it 10 times.
coll.insert_one({"name": "John Doe"})
for _ in range(10):
coll.find_one({"name": "John Doe"})
# Confirm all find commands are run against appropriate host.
for command in listener.started_events:
if command.command_name == "find":
self.assertEqual(command.connection_id[1], expected_port)
def test_invalid_server_selector(self):
# Client initialization must fail if server_selector is not callable.
for selector_candidate in [[], 10, "string", {}]:
with self.assertRaisesRegex(ValueError, "must be a callable"):
MongoClient(connect=False, server_selector=selector_candidate)
# None value for server_selector is OK.
MongoClient(connect=False, server_selector=None)
@client_context.require_replica_set
def test_selector_called(self):
selector = FunctionCallRecorder(lambda x: x)
# Client setup.
mongo_client = self.rs_or_single_client(server_selector=selector)
test_collection = mongo_client.testdb.test_collection
self.addCleanup(mongo_client.close)
self.addCleanup(mongo_client.drop_database, "testdb")
# Do N operations and test selector is called at least N times.
test_collection.insert_one({"age": 20, "name": "John"})
test_collection.insert_one({"age": 31, "name": "Jane"})
test_collection.update_one({"name": "Jane"}, {"$set": {"age": 21}})
test_collection.find_one({"name": "Roe"})
self.assertGreaterEqual(selector.call_count, 4)
@client_context.require_replica_set
def test_latency_threshold_application(self):
selector = SelectionStoreSelector()
scenario_def: dict = {
"topology_description": {
"type": "ReplicaSetWithPrimary",
"servers": [
{"address": "b:27017", "avg_rtt_ms": 10000, "type": "RSSecondary", "tag": {}},
{"address": "c:27017", "avg_rtt_ms": 20000, "type": "RSSecondary", "tag": {}},
{"address": "a:27017", "avg_rtt_ms": 30000, "type": "RSPrimary", "tag": {}},
],
}
}
# Create & populate Topology such that all but one server is too slow.
rtt_times = [srv["avg_rtt_ms"] for srv in scenario_def["topology_description"]["servers"]]
min_rtt_idx = rtt_times.index(min(rtt_times))
seeds, hosts = get_addresses(scenario_def["topology_description"]["servers"])
settings = get_topology_settings_dict(
heartbeat_frequency=1, local_threshold_ms=1, seeds=seeds, server_selector=selector
)
topology = Topology(TopologySettings(**settings))
topology.open()
for server in scenario_def["topology_description"]["servers"]:
server_description = make_server_description(server, hosts)
topology.on_change(server_description)
# Invoke server selection and assert no filtering based on latency
# prior to custom server selection logic kicking in.
server = topology.select_server(ReadPreference.NEAREST, _Op.TEST)
assert selector.selection is not None
self.assertEqual(len(selector.selection), len(topology.description.server_descriptions()))
# Ensure proper filtering based on latency after custom selection.
self.assertEqual(server.description.address, seeds[min_rtt_idx])
@client_context.require_replica_set
def test_server_selector_bypassed(self):
selector = FunctionCallRecorder(lambda x: x)
scenario_def = {
"topology_description": {
"type": "ReplicaSetNoPrimary",
"servers": [
{"address": "b:27017", "avg_rtt_ms": 10000, "type": "RSSecondary", "tag": {}},
{"address": "c:27017", "avg_rtt_ms": 20000, "type": "RSSecondary", "tag": {}},
{"address": "a:27017", "avg_rtt_ms": 30000, "type": "RSSecondary", "tag": {}},
],
}
}
# Create & populate Topology such that no server is writeable.
seeds, hosts = get_addresses(scenario_def["topology_description"]["servers"])
settings = get_topology_settings_dict(
heartbeat_frequency=1, local_threshold_ms=1, seeds=seeds, server_selector=selector
)
topology = Topology(TopologySettings(**settings))
topology.open()
for server in scenario_def["topology_description"]["servers"]:
server_description = make_server_description(server, hosts)
topology.on_change(server_description)
# Invoke server selection and assert no calls to our custom selector.
with self.assertRaisesRegex(ServerSelectionTimeoutError, "No primary available for writes"):
topology.select_server(writable_server_selector, _Op.TEST, server_selection_timeout=0.1)
self.assertEqual(selector.call_count, 0)
if __name__ == "__main__":
unittest.main()