mirror of
https://git.anonymousland.org/anonymousland/synapse.git
synced 2024-12-27 06:19:23 -05:00
642199570c
Let's try to rationalise the logging that happens when we are processing an incoming transaction, to make it easier to figure out what is going wrong when they take ages. In particular: - make everything start with a [room_id event_id] prefix - make sure we log a warning when catching exceptions rather than just turning them into other, more cryptic, exceptions.
210 lines
7.9 KiB
Python
210 lines
7.9 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2015, 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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import random
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from twisted.internet import defer
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import synapse.util.logcontext
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from synapse.api.errors import CodeMessageException
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logger = logging.getLogger(__name__)
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class NotRetryingDestination(Exception):
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def __init__(self, retry_last_ts, retry_interval, destination):
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"""Raised by the limiter (and federation client) to indicate that we are
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are deliberately not attempting to contact a given server.
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Args:
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retry_last_ts (int): the unix ts in milliseconds of our last attempt
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to contact the server. 0 indicates that the last attempt was
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successful or that we've never actually attempted to connect.
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retry_interval (int): the time in milliseconds to wait until the next
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attempt.
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destination (str): the domain in question
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"""
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msg = "Not retrying server %s." % (destination,)
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super(NotRetryingDestination, self).__init__(msg)
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self.retry_last_ts = retry_last_ts
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self.retry_interval = retry_interval
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self.destination = destination
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@defer.inlineCallbacks
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def get_retry_limiter(destination, clock, store, ignore_backoff=False,
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**kwargs):
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"""For a given destination check if we have previously failed to
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send a request there and are waiting before retrying the destination.
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If we are not ready to retry the destination, this will raise a
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NotRetryingDestination exception. Otherwise, will return a Context Manager
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that will mark the destination as down if an exception is thrown (excluding
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CodeMessageException with code < 500)
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Args:
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destination (str): name of homeserver
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clock (synapse.util.clock): timing source
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store (synapse.storage.transactions.TransactionStore): datastore
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ignore_backoff (bool): true to ignore the historical backoff data and
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try the request anyway. We will still update the next
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retry_interval on success/failure.
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Example usage:
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try:
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limiter = yield get_retry_limiter(destination, clock, store)
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with limiter:
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response = yield do_request()
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except NotRetryingDestination:
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# We aren't ready to retry that destination.
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raise
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"""
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retry_last_ts, retry_interval = (0, 0)
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retry_timings = yield store.get_destination_retry_timings(
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destination
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)
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if retry_timings:
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retry_last_ts, retry_interval = (
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retry_timings["retry_last_ts"], retry_timings["retry_interval"]
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)
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now = int(clock.time_msec())
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if not ignore_backoff and retry_last_ts + retry_interval > now:
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raise NotRetryingDestination(
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retry_last_ts=retry_last_ts,
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retry_interval=retry_interval,
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destination=destination,
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)
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defer.returnValue(
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RetryDestinationLimiter(
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destination,
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clock,
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store,
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retry_interval,
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**kwargs
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)
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)
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class RetryDestinationLimiter(object):
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def __init__(self, destination, clock, store, retry_interval,
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min_retry_interval=10 * 60 * 1000,
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max_retry_interval=24 * 60 * 60 * 1000,
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multiplier_retry_interval=5, backoff_on_404=False):
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"""Marks the destination as "down" if an exception is thrown in the
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context, except for CodeMessageException with code < 500.
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If no exception is raised, marks the destination as "up".
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Args:
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destination (str)
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clock (Clock)
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store (DataStore)
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retry_interval (int): The next retry interval taken from the
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database in milliseconds, or zero if the last request was
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successful.
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min_retry_interval (int): The minimum retry interval to use after
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a failed request, in milliseconds.
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max_retry_interval (int): The maximum retry interval to use after
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a failed request, in milliseconds.
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multiplier_retry_interval (int): The multiplier to use to increase
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the retry interval after a failed request.
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backoff_on_404 (bool): Back off if we get a 404
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"""
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self.clock = clock
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self.store = store
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self.destination = destination
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self.retry_interval = retry_interval
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self.min_retry_interval = min_retry_interval
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self.max_retry_interval = max_retry_interval
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self.multiplier_retry_interval = multiplier_retry_interval
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self.backoff_on_404 = backoff_on_404
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def __enter__(self):
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pass
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def __exit__(self, exc_type, exc_val, exc_tb):
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valid_err_code = False
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if exc_type is None:
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valid_err_code = True
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elif not issubclass(exc_type, Exception):
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# avoid treating exceptions which don't derive from Exception as
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# failures; this is mostly so as not to catch defer._DefGen.
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valid_err_code = True
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elif issubclass(exc_type, CodeMessageException):
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# Some error codes are perfectly fine for some APIs, whereas other
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# APIs may expect to never received e.g. a 404. It's important to
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# handle 404 as some remote servers will return a 404 when the HS
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# has been decommissioned.
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# If we get a 401, then we should probably back off since they
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# won't accept our requests for at least a while.
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# 429 is us being aggresively rate limited, so lets rate limit
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# ourselves.
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if exc_val.code == 404 and self.backoff_on_404:
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valid_err_code = False
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elif exc_val.code in (401, 429):
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valid_err_code = False
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elif exc_val.code < 500:
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valid_err_code = True
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else:
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valid_err_code = False
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if valid_err_code:
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# We connected successfully.
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if not self.retry_interval:
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return
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logger.debug("Connection to %s was successful; clearing backoff",
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self.destination)
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retry_last_ts = 0
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self.retry_interval = 0
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else:
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# We couldn't connect.
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if self.retry_interval:
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self.retry_interval *= self.multiplier_retry_interval
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self.retry_interval *= int(random.uniform(0.8, 1.4))
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if self.retry_interval >= self.max_retry_interval:
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self.retry_interval = self.max_retry_interval
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else:
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self.retry_interval = self.min_retry_interval
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logger.info(
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"Connection to %s was unsuccessful (%s(%s)); backoff now %i",
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self.destination, exc_type, exc_val, self.retry_interval
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)
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retry_last_ts = int(self.clock.time_msec())
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@defer.inlineCallbacks
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def store_retry_timings():
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try:
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yield self.store.set_destination_retry_timings(
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self.destination, retry_last_ts, self.retry_interval
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)
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except Exception:
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logger.exception(
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"Failed to store destination_retry_timings",
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)
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# we deliberately do this in the background.
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synapse.util.logcontext.run_in_background(store_retry_timings)
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