mirror of
https://git.anonymousland.org/anonymousland/synapse-product.git
synced 2024-12-20 19:14:20 -05:00
109 lines
4.3 KiB
Python
109 lines
4.3 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2014-2016 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.
|
|
|
|
"""This module contains logic for storing HTTP PUT transactions. This is used
|
|
to ensure idempotency when performing PUTs using the REST API."""
|
|
import logging
|
|
|
|
from synapse.logging.context import make_deferred_yieldable, run_in_background
|
|
from synapse.util.async_helpers import ObservableDeferred
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
CLEANUP_PERIOD_MS = 1000 * 60 * 30 # 30 mins
|
|
|
|
|
|
class HttpTransactionCache:
|
|
def __init__(self, hs):
|
|
self.hs = hs
|
|
self.auth = self.hs.get_auth()
|
|
self.clock = self.hs.get_clock()
|
|
self.transactions = {
|
|
# $txn_key: (ObservableDeferred<(res_code, res_json_body)>, timestamp)
|
|
}
|
|
# Try to clean entries every 30 mins. This means entries will exist
|
|
# for at *LEAST* 30 mins, and at *MOST* 60 mins.
|
|
self.cleaner = self.clock.looping_call(self._cleanup, CLEANUP_PERIOD_MS)
|
|
|
|
def _get_transaction_key(self, request):
|
|
"""A helper function which returns a transaction key that can be used
|
|
with TransactionCache for idempotent requests.
|
|
|
|
Idempotency is based on the returned key being the same for separate
|
|
requests to the same endpoint. The key is formed from the HTTP request
|
|
path and the access_token for the requesting user.
|
|
|
|
Args:
|
|
request (twisted.web.http.Request): The incoming request. Must
|
|
contain an access_token.
|
|
Returns:
|
|
str: A transaction key
|
|
"""
|
|
token = self.auth.get_access_token_from_request(request)
|
|
return request.path.decode("utf8") + "/" + token
|
|
|
|
def fetch_or_execute_request(self, request, fn, *args, **kwargs):
|
|
"""A helper function for fetch_or_execute which extracts
|
|
a transaction key from the given request.
|
|
|
|
See:
|
|
fetch_or_execute
|
|
"""
|
|
return self.fetch_or_execute(
|
|
self._get_transaction_key(request), fn, *args, **kwargs
|
|
)
|
|
|
|
def fetch_or_execute(self, txn_key, fn, *args, **kwargs):
|
|
"""Fetches the response for this transaction, or executes the given function
|
|
to produce a response for this transaction.
|
|
|
|
Args:
|
|
txn_key (str): A key to ensure idempotency should fetch_or_execute be
|
|
called again at a later point in time.
|
|
fn (function): A function which returns a tuple of
|
|
(response_code, response_dict).
|
|
*args: Arguments to pass to fn.
|
|
**kwargs: Keyword arguments to pass to fn.
|
|
Returns:
|
|
Deferred which resolves to a tuple of (response_code, response_dict).
|
|
"""
|
|
if txn_key in self.transactions:
|
|
observable = self.transactions[txn_key][0]
|
|
else:
|
|
# execute the function instead.
|
|
deferred = run_in_background(fn, *args, **kwargs)
|
|
|
|
observable = ObservableDeferred(deferred)
|
|
self.transactions[txn_key] = (observable, self.clock.time_msec())
|
|
|
|
# if the request fails with an exception, remove it
|
|
# from the transaction map. This is done to ensure that we don't
|
|
# cache transient errors like rate-limiting errors, etc.
|
|
def remove_from_map(err):
|
|
self.transactions.pop(txn_key, None)
|
|
# we deliberately do not propagate the error any further, as we
|
|
# expect the observers to have reported it.
|
|
|
|
deferred.addErrback(remove_from_map)
|
|
|
|
return make_deferred_yieldable(observable.observe())
|
|
|
|
def _cleanup(self):
|
|
now = self.clock.time_msec()
|
|
for key in list(self.transactions):
|
|
ts = self.transactions[key][1]
|
|
if now > (ts + CLEANUP_PERIOD_MS): # after cleanup period
|
|
del self.transactions[key]
|