diff options
Diffstat (limited to 'synapse/util')
| -rw-r--r-- | synapse/util/__init__.py | 2 | ||||
| -rw-r--r-- | synapse/util/expiringcache.py | 115 | ||||
| -rw-r--r-- | synapse/util/retryutils.py | 153 |
3 files changed, 268 insertions, 2 deletions
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py index e77eba90ad..79109d0b19 100644 --- a/synapse/util/__init__.py +++ b/synapse/util/__init__.py @@ -99,8 +99,6 @@ class Clock(object): except: pass - return res - given_deferred.addCallbacks(callback=sucess, errback=err) timer = self.call_later(time_out, timed_out_fn) diff --git a/synapse/util/expiringcache.py b/synapse/util/expiringcache.py new file mode 100644 index 0000000000..1c7859297a --- /dev/null +++ b/synapse/util/expiringcache.py @@ -0,0 +1,115 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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. + +import logging + + +logger = logging.getLogger(__name__) + + +class ExpiringCache(object): + def __init__(self, cache_name, clock, max_len=0, expiry_ms=0, + reset_expiry_on_get=False): + """ + Args: + cache_name (str): Name of this cache, used for logging. + clock (Clock) + max_len (int): Max size of dict. If the dict grows larger than this + then the oldest items get automatically evicted. Default is 0, + which indicates there is no max limit. + expiry_ms (int): How long before an item is evicted from the cache + in milliseconds. Default is 0, indicating items never get + evicted based on time. + reset_expiry_on_get (bool): If true, will reset the expiry time for + an item on access. Defaults to False. + + """ + self._cache_name = cache_name + + self._clock = clock + + self._max_len = max_len + self._expiry_ms = expiry_ms + + self._reset_expiry_on_get = reset_expiry_on_get + + self._cache = {} + + def start(self): + if not self._expiry_ms: + # Don't bother starting the loop if things never expire + return + + def f(): + self._prune_cache() + + self._clock.looping_call(f, self._expiry_ms/2) + + def __setitem__(self, key, value): + now = self._clock.time_msec() + self._cache[key] = _CacheEntry(now, value) + + # Evict if there are now too many items + if self._max_len and len(self._cache.keys()) > self._max_len: + sorted_entries = sorted( + self._cache.items(), + key=lambda k, v: v.time, + ) + + for k, _ in sorted_entries[self._max_len:]: + self._cache.pop(k) + + def __getitem__(self, key): + entry = self._cache[key] + + if self._reset_expiry_on_get: + entry.time = self._clock.time_msec() + + return entry.value + + def get(self, key, default=None): + try: + return self[key] + except KeyError: + return default + + def _prune_cache(self): + if not self._expiry_ms: + # zero expiry time means don't expire. This should never get called + # since we have this check in start too. + return + begin_length = len(self._cache) + + now = self._clock.time_msec() + + keys_to_delete = set() + + for key, cache_entry in self._cache.items(): + if now - cache_entry.time > self._expiry_ms: + keys_to_delete.add(key) + + for k in keys_to_delete: + self._cache.pop(k) + + logger.debug( + "[%s] _prune_cache before: %d, after len: %d", + self._cache_name, begin_length, len(self._cache.keys()) + ) + + +class _CacheEntry(object): + def __init__(self, time, value): + self.time = time + self.value = value diff --git a/synapse/util/retryutils.py b/synapse/util/retryutils.py new file mode 100644 index 0000000000..4e82232796 --- /dev/null +++ b/synapse/util/retryutils.py @@ -0,0 +1,153 @@ +# -*- coding: utf-8 -*- +# Copyright 2015 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 import defer + +from synapse.api.errors import CodeMessageException + +import logging + + +logger = logging.getLogger(__name__) + + +class NotRetryingDestination(Exception): + def __init__(self, retry_last_ts, retry_interval, destination): + msg = "Not retrying server %s." % (destination,) + super(NotRetryingDestination, self).__init__(msg) + + self.retry_last_ts = retry_last_ts + self.retry_interval = retry_interval + self.destination = destination + + +@defer.inlineCallbacks +def get_retry_limiter(destination, clock, store, **kwargs): + """For a given destination check if we have previously failed to + send a request there and are waiting before retrying the destination. + If we are not ready to retry the destination, this will raise a + NotRetryingDestination exception. Otherwise, will return a Context Manager + that will mark the destination as down if an exception is thrown (excluding + CodeMessageException with code < 500) + + Example usage: + + try: + limiter = yield get_retry_limiter(destination, clock, store) + with limiter: + response = yield do_request() + except NotRetryingDestination: + # We aren't ready to retry that destination. + raise + """ + retry_last_ts, retry_interval = (0, 0) + + retry_timings = yield store.get_destination_retry_timings( + destination + ) + + if retry_timings: + retry_last_ts, retry_interval = ( + retry_timings.retry_last_ts, retry_timings.retry_interval + ) + + now = int(clock.time_msec()) + + if retry_last_ts + retry_interval > now: + raise NotRetryingDestination( + retry_last_ts=retry_last_ts, + retry_interval=retry_interval, + destination=destination, + ) + + defer.returnValue( + RetryDestinationLimiter( + destination, + clock, + store, + retry_interval, + **kwargs + ) + ) + + +class RetryDestinationLimiter(object): + def __init__(self, destination, clock, store, retry_interval, + min_retry_interval=5000, max_retry_interval=60 * 60 * 1000, + multiplier_retry_interval=2,): + """Marks the destination as "down" if an exception is thrown in the + context, except for CodeMessageException with code < 500. + + If no exception is raised, marks the destination as "up". + + Args: + destination (str) + clock (Clock) + store (DataStore) + retry_interval (int): The next retry interval taken from the + database in milliseconds, or zero if the last request was + successful. + min_retry_interval (int): The minimum retry interval to use after + a failed request, in milliseconds. + max_retry_interval (int): The maximum retry interval to use after + a failed request, in milliseconds. + multiplier_retry_interval (int): The multiplier to use to increase + the retry interval after a failed request. + """ + self.clock = clock + self.store = store + self.destination = destination + + self.retry_interval = retry_interval + self.min_retry_interval = min_retry_interval + self.max_retry_interval = max_retry_interval + self.multiplier_retry_interval = multiplier_retry_interval + + def __enter__(self): + pass + + def __exit__(self, exc_type, exc_val, exc_tb): + def err(failure): + logger.exception( + "Failed to store set_destination_retry_timings", + failure.value + ) + + valid_err_code = False + if exc_type is CodeMessageException: + valid_err_code = 0 <= exc_val.code < 500 + + if exc_type is None or valid_err_code: + # We connected successfully. + if not self.retry_interval: + return + + retry_last_ts = 0 + self.retry_interval = 0 + else: + # We couldn't connect. + if self.retry_interval: + self.retry_interval *= self.multiplier_retry_interval + + if self.retry_interval >= self.max_retry_interval: + self.retry_interval = self.max_retry_interval + else: + self.retry_interval = self.min_retry_interval + + retry_last_ts = int(self.clock.time_msec()) + + self.store.set_destination_retry_timings( + self.destination, retry_last_ts, self.retry_interval + ).addErrback(err) |