synapse/tests/rest/client/test_transactions.py
Eric Eastwood 5143f93dc9
Fix server_name in logging context for multiple Synapse instances in one process (#18868)
### Background

As part of Element's plan to support a light form of vhosting (virtual
host) (multiple instances of Synapse in the same Python process), we're
currently diving into the details and implications of running multiple
instances of Synapse in the same Python process.

"Per-tenant logging" tracked internally by
https://github.com/element-hq/synapse-small-hosts/issues/48

### Prior art

Previously, we exposed `server_name` by providing a static logging
`MetadataFilter` that injected the values:


205d9e4fc4/synapse/config/logger.py (L216)

While this can work fine for the normal case of one Synapse instance per
Python process, this configures things globally and isn't compatible
when we try to start multiple Synapse instances because each subsequent
tenant will overwrite the previous tenant.


### What does this PR do?

We remove the `MetadataFilter` and replace it by tracking the
`server_name` in the `LoggingContext` and expose it with our existing
[`LoggingContextFilter`](205d9e4fc4/synapse/logging/context.py (L584-L622))
that we already use to expose information about the `request`.

This means that the `server_name` value follows wherever we log as
expected even when we have multiple Synapse instances running in the
same process.


### A note on logcontext

Anywhere, Synapse mistakenly uses the `sentinel` logcontext to log
something, we won't know which server sent the log. We've been fixing up
`sentinel` logcontext usage as tracked by
https://github.com/element-hq/synapse/issues/18905

Any further `sentinel` logcontext usage we find in the future can be
fixed piecemeal as normal.


d2a966f922/docs/log_contexts.md (L71-L81)


### Testing strategy

1. Adjust your logging config to include `%(server_name)s` in the format
    ```yaml
    formatters:
        precise:
format: '%(asctime)s - %(server_name)s - %(name)s - %(lineno)d -
%(levelname)s - %(request)s - %(message)s'
    ```
1. Start Synapse: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Make some requests (`curl
http://localhost:8008/_matrix/client/versions`, etc)
1. Open the homeserver logs and notice the `server_name` in the logs as
expected. `unknown_server_from_sentinel_context` is expected for the
`sentinel` logcontext (things outside of Synapse).
2025-09-26 17:10:48 -05:00

200 lines
7.4 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2018-2021 The Matrix.org Foundation C.I.C.
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
from http import HTTPStatus
from typing import Any, Generator, Tuple, cast
from unittest.mock import AsyncMock, Mock, call
from twisted.internet import defer, reactor as _reactor
from synapse.logging.context import SENTINEL_CONTEXT, LoggingContext, current_context
from synapse.rest.client.transactions import CLEANUP_PERIOD_MS, HttpTransactionCache
from synapse.types import ISynapseReactor, JsonDict
from synapse.util.clock import Clock
from tests import unittest
from tests.utils import MockClock
reactor = cast(ISynapseReactor, _reactor)
class HttpTransactionCacheTestCase(unittest.TestCase):
def setUp(self) -> None:
self.clock = MockClock()
self.hs = Mock()
self.hs.get_clock = Mock(return_value=self.clock)
self.hs.get_auth = Mock()
self.cache = HttpTransactionCache(self.hs)
self.mock_http_response = (HTTPStatus.OK, {"result": "GOOD JOB!"})
# Here we make sure that we're setting all the fields that HttpTransactionCache
# uses to build the transaction key.
self.mock_request = Mock()
self.mock_request.path = b"/foo/bar"
self.mock_requester = Mock()
self.mock_requester.app_service = None
self.mock_requester.is_guest = False
self.mock_requester.access_token_id = 1234
@defer.inlineCallbacks
def test_executes_given_function(
self,
) -> Generator["defer.Deferred[Any]", object, None]:
cb = AsyncMock(return_value=self.mock_http_response)
res = yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb, "some_arg", keyword="arg"
)
cb.assert_called_once_with("some_arg", keyword="arg")
self.assertEqual(res, self.mock_http_response)
@defer.inlineCallbacks
def test_deduplicates_based_on_key(
self,
) -> Generator["defer.Deferred[Any]", object, None]:
cb = AsyncMock(return_value=self.mock_http_response)
for i in range(3): # invoke multiple times
res = yield self.cache.fetch_or_execute_request(
self.mock_request,
self.mock_requester,
cb,
"some_arg",
keyword="arg",
changing_args=i,
)
self.assertEqual(res, self.mock_http_response)
# expect only a single call to do the work
cb.assert_called_once_with("some_arg", keyword="arg", changing_args=0)
@defer.inlineCallbacks
def test_logcontexts_with_async_result(
self,
) -> Generator["defer.Deferred[Any]", object, None]:
@defer.inlineCallbacks
def cb() -> Generator["defer.Deferred[object]", object, Tuple[int, JsonDict]]:
yield defer.ensureDeferred(
Clock(reactor, server_name="test_server").sleep(0)
)
return 1, {}
@defer.inlineCallbacks
def test() -> Generator["defer.Deferred[Any]", object, None]:
with LoggingContext(name="c", server_name="test_server") as c1:
res = yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb
)
self.assertIs(current_context(), c1)
self.assertEqual(res, (1, {}))
# run the test twice in parallel
d = defer.gatherResults([test(), test()])
self.assertIs(current_context(), SENTINEL_CONTEXT)
yield d
self.assertIs(current_context(), SENTINEL_CONTEXT)
@defer.inlineCallbacks
def test_does_not_cache_exceptions(
self,
) -> Generator["defer.Deferred[Any]", object, None]:
"""Checks that, if the callback throws an exception, it is called again
for the next request.
"""
called = [False]
def cb() -> "defer.Deferred[Tuple[int, JsonDict]]":
if called[0]:
# return a valid result the second time
return defer.succeed(self.mock_http_response)
called[0] = True
raise Exception("boo")
with LoggingContext(name="test", server_name="test_server") as test_context:
try:
yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb
)
except Exception as e:
self.assertEqual(e.args[0], "boo")
self.assertIs(current_context(), test_context)
res = yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb
)
self.assertEqual(res, self.mock_http_response)
self.assertIs(current_context(), test_context)
@defer.inlineCallbacks
def test_does_not_cache_failures(
self,
) -> Generator["defer.Deferred[Any]", object, None]:
"""Checks that, if the callback returns a failure, it is called again
for the next request.
"""
called = [False]
def cb() -> "defer.Deferred[Tuple[int, JsonDict]]":
if called[0]:
# return a valid result the second time
return defer.succeed(self.mock_http_response)
called[0] = True
return defer.fail(Exception("boo"))
with LoggingContext(name="test", server_name="test_server") as test_context:
try:
yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb
)
except Exception as e:
self.assertEqual(e.args[0], "boo")
self.assertIs(current_context(), test_context)
res = yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb
)
self.assertEqual(res, self.mock_http_response)
self.assertIs(current_context(), test_context)
@defer.inlineCallbacks
def test_cleans_up(self) -> Generator["defer.Deferred[Any]", object, None]:
cb = AsyncMock(return_value=self.mock_http_response)
yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb, "an arg"
)
# should NOT have cleaned up yet
self.clock.advance_time_msec(CLEANUP_PERIOD_MS / 2)
yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb, "an arg"
)
# still using cache
cb.assert_called_once_with("an arg")
self.clock.advance_time_msec(CLEANUP_PERIOD_MS)
yield self.cache.fetch_or_execute_request(
self.mock_request, self.mock_requester, cb, "an arg"
)
# no longer using cache
self.assertEqual(cb.call_count, 2)
self.assertEqual(cb.call_args_list, [call("an arg"), call("an arg")])