diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 81dce96f4b..73c110a92b 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -26,7 +26,7 @@ from synapse.streams.config import PaginationConfig
from synapse.types import StreamToken, UserID
from synapse.util import unwrapFirstError
from synapse.util.async_helpers import concurrently_execute
-from synapse.util.caches.snapshot_cache import SnapshotCache
+from synapse.util.caches.response_cache import ResponseCache
from synapse.visibility import filter_events_for_client
from ._base import BaseHandler
@@ -41,7 +41,7 @@ class InitialSyncHandler(BaseHandler):
self.state = hs.get_state_handler()
self.clock = hs.get_clock()
self.validator = EventValidator()
- self.snapshot_cache = SnapshotCache()
+ self.snapshot_cache = ResponseCache(hs, "initial_sync_cache")
self._event_serializer = hs.get_event_client_serializer()
self.storage = hs.get_storage()
self.state_store = self.storage.state
@@ -79,17 +79,14 @@ class InitialSyncHandler(BaseHandler):
as_client_event,
include_archived,
)
- now_ms = self.clock.time_msec()
- result = self.snapshot_cache.get(now_ms, key)
- if result is not None:
- return result
- return self.snapshot_cache.set(
- now_ms,
+ return self.snapshot_cache.wrap(
key,
- self._snapshot_all_rooms(
- user_id, pagin_config, as_client_event, include_archived
- ),
+ self._snapshot_all_rooms,
+ user_id,
+ pagin_config,
+ as_client_event,
+ include_archived,
)
@defer.inlineCallbacks
diff --git a/synapse/util/caches/snapshot_cache.py b/synapse/util/caches/snapshot_cache.py
deleted file mode 100644
index 8318db8d2c..0000000000
--- a/synapse/util/caches/snapshot_cache.py
+++ /dev/null
@@ -1,94 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2015, 2016 OpenMarket Ltd
-#
-# 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.
-
-from synapse.util.async_helpers import ObservableDeferred
-
-
-class SnapshotCache(object):
- """Cache for snapshots like the response of /initialSync.
- The response of initialSync only has to be a recent snapshot of the
- server state. It shouldn't matter to clients if it is a few minutes out
- of date.
-
- This caches a deferred response. Until the deferred completes it will be
- returned from the cache. This means that if the client retries the request
- while the response is still being computed, that original response will be
- used rather than trying to compute a new response.
-
- Once the deferred completes it will removed from the cache after 5 minutes.
- We delay removing it from the cache because a client retrying its request
- could race with us finishing computing the response.
-
- Rather than tracking precisely how long something has been in the cache we
- keep two generations of completed responses. Every 5 minutes discard the
- old generation, move the new generation to the old generation, and set the
- new generation to be empty. This means that a result will be in the cache
- somewhere between 5 and 10 minutes.
- """
-
- DURATION_MS = 5 * 60 * 1000 # Cache results for 5 minutes.
-
- def __init__(self):
- self.pending_result_cache = {} # Request that haven't finished yet.
- self.prev_result_cache = {} # The older requests that have finished.
- self.next_result_cache = {} # The newer requests that have finished.
- self.time_last_rotated_ms = 0
-
- def rotate(self, time_now_ms):
- # Rotate once if the cache duration has passed since the last rotation.
- if time_now_ms - self.time_last_rotated_ms >= self.DURATION_MS:
- self.prev_result_cache = self.next_result_cache
- self.next_result_cache = {}
- self.time_last_rotated_ms += self.DURATION_MS
-
- # Rotate again if the cache duration has passed twice since the last
- # rotation.
- if time_now_ms - self.time_last_rotated_ms >= self.DURATION_MS:
- self.prev_result_cache = self.next_result_cache
- self.next_result_cache = {}
- self.time_last_rotated_ms = time_now_ms
-
- def get(self, time_now_ms, key):
- self.rotate(time_now_ms)
- # This cache is intended to deduplicate requests, so we expect it to be
- # missed most of the time. So we just lookup the key in all of the
- # dictionaries rather than trying to short circuit the lookup if the
- # key is found.
- result = self.prev_result_cache.get(key)
- result = self.next_result_cache.get(key, result)
- result = self.pending_result_cache.get(key, result)
- if result is not None:
- return result.observe()
- else:
- return None
-
- def set(self, time_now_ms, key, deferred):
- self.rotate(time_now_ms)
-
- result = ObservableDeferred(deferred)
-
- self.pending_result_cache[key] = result
-
- def shuffle_along(r):
- # When the deferred completes we shuffle it along to the first
- # generation of the result cache. So that it will eventually
- # expire from the rotation of that cache.
- self.next_result_cache[key] = result
- self.pending_result_cache.pop(key, None)
- return r
-
- result.addBoth(shuffle_along)
-
- return result.observe()
diff --git a/tests/util/test_snapshot_cache.py b/tests/util/test_snapshot_cache.py
deleted file mode 100644
index 1a44f72425..0000000000
--- a/tests/util/test_snapshot_cache.py
+++ /dev/null
@@ -1,63 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2015, 2016 OpenMarket Ltd
-#
-# 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.
-
-
-from twisted.internet.defer import Deferred
-
-from synapse.util.caches.snapshot_cache import SnapshotCache
-
-from .. import unittest
-
-
-class SnapshotCacheTestCase(unittest.TestCase):
- def setUp(self):
- self.cache = SnapshotCache()
- self.cache.DURATION_MS = 1
-
- def test_get_set(self):
- # Check that getting a missing key returns None
- self.assertEquals(self.cache.get(0, "key"), None)
-
- # Check that setting a key with a deferred returns
- # a deferred that resolves when the initial deferred does
- d = Deferred()
- set_result = self.cache.set(0, "key", d)
- self.assertIsNotNone(set_result)
- self.assertFalse(set_result.called)
-
- # Check that getting the key before the deferred has resolved
- # returns a deferred that resolves when the initial deferred does.
- get_result_at_10 = self.cache.get(10, "key")
- self.assertIsNotNone(get_result_at_10)
- self.assertFalse(get_result_at_10.called)
-
- # Check that the returned deferreds resolve when the initial deferred
- # does.
- d.callback("v")
- self.assertTrue(set_result.called)
- self.assertTrue(get_result_at_10.called)
-
- # Check that getting the key after the deferred has resolved
- # before the cache expires returns a resolved deferred.
- get_result_at_11 = self.cache.get(11, "key")
- self.assertIsNotNone(get_result_at_11)
- if isinstance(get_result_at_11, Deferred):
- # The cache may return the actual result rather than a deferred
- self.assertTrue(get_result_at_11.called)
-
- # Check that getting the key after the deferred has resolved
- # after the cache expires returns None
- get_result_at_12 = self.cache.get(12, "key")
- self.assertIsNone(get_result_at_12)
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