synapse/tests/rest/client/test_transactions.py
Richard van der Hoff 6d6e7288fe Stop the transaction cache caching failures
The transaction cache has some code which tries to stop it caching failures,
but if the callback function failed straight away, then things would happen
backwards and we'd end up with the failure stuck in the cache.
2018-05-21 16:49:59 +01:00

123 lines
4.2 KiB
Python

from synapse.rest.client.transactions import HttpTransactionCache
from synapse.rest.client.transactions import CLEANUP_PERIOD_MS
from twisted.internet import defer
from mock import Mock, call
from synapse.util.logcontext import LoggingContext
from tests import unittest
from tests.utils import MockClock
class HttpTransactionCacheTestCase(unittest.TestCase):
def setUp(self):
self.clock = MockClock()
self.cache = HttpTransactionCache(self.clock)
self.mock_http_response = (200, "GOOD JOB!")
self.mock_key = "foo"
@defer.inlineCallbacks
def test_executes_given_function(self):
cb = Mock(
return_value=defer.succeed(self.mock_http_response)
)
res = yield self.cache.fetch_or_execute(
self.mock_key, 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):
cb = Mock(
return_value=defer.succeed(self.mock_http_response)
)
for i in range(3): # invoke multiple times
res = yield self.cache.fetch_or_execute(
self.mock_key, 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_does_not_cache_exceptions(self):
"""Checks that, if the callback throws an exception, it is called again
for the next request.
"""
called = [False]
def cb():
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("test") as test_context:
try:
yield self.cache.fetch_or_execute(self.mock_key, cb)
except Exception as e:
self.assertEqual(e.message, "boo")
self.assertIs(LoggingContext.current_context(), test_context)
res = yield self.cache.fetch_or_execute(self.mock_key, cb)
self.assertEqual(res, self.mock_http_response)
self.assertIs(LoggingContext.current_context(), test_context)
@defer.inlineCallbacks
def test_does_not_cache_failures(self):
"""Checks that, if the callback returns a failure, it is called again
for the next request.
"""
called = [False]
def cb():
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("test") as test_context:
try:
yield self.cache.fetch_or_execute(self.mock_key, cb)
except Exception as e:
self.assertEqual(e.message, "boo")
self.assertIs(LoggingContext.current_context(), test_context)
res = yield self.cache.fetch_or_execute(self.mock_key, cb)
self.assertEqual(res, self.mock_http_response)
self.assertIs(LoggingContext.current_context(), test_context)
@defer.inlineCallbacks
def test_cleans_up(self):
cb = Mock(
return_value=defer.succeed(self.mock_http_response)
)
yield self.cache.fetch_or_execute(
self.mock_key, cb, "an arg"
)
# should NOT have cleaned up yet
self.clock.advance_time_msec(CLEANUP_PERIOD_MS / 2)
yield self.cache.fetch_or_execute(
self.mock_key, 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(
self.mock_key, 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",)]
)