forked-synapse/synapse/replication/http/_base.py
Richard van der Hoff 3e99528f2b
Store room version on invite (#6983)
When we get an invite over federation, store the room version in the rooms table.

The general idea here is that, when we pull the invite out again, we'll want to know what room_version it belongs to (so that we can later redact it if need be). So we need to store it somewhere...
2020-02-26 16:58:33 +00:00

234 lines
8.6 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2018 New Vector 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 abc
import logging
import re
from typing import Dict, List, Tuple
from six import raise_from
from six.moves import urllib
from twisted.internet import defer
from synapse.api.errors import (
CodeMessageException,
HttpResponseException,
RequestSendFailed,
SynapseError,
)
from synapse.logging.opentracing import (
inject_active_span_byte_dict,
trace,
trace_servlet,
)
from synapse.util.caches.response_cache import ResponseCache
from synapse.util.stringutils import random_string
logger = logging.getLogger(__name__)
class ReplicationEndpoint(object):
"""Helper base class for defining new replication HTTP endpoints.
This creates an endpoint under `/_synapse/replication/:NAME/:PATH_ARGS..`
(with a `/:txn_id` suffix for cached requests), where NAME is a name,
PATH_ARGS are a tuple of parameters to be encoded in the URL.
For example, if `NAME` is "send_event" and `PATH_ARGS` is `("event_id",)`,
with `CACHE` set to true then this generates an endpoint:
/_synapse/replication/send_event/:event_id/:txn_id
For POST/PUT requests the payload is serialized to json and sent as the
body, while for GET requests the payload is added as query parameters. See
`_serialize_payload` for details.
Incoming requests are handled by overriding `_handle_request`. Servers
must call `register` to register the path with the HTTP server.
Requests can be sent by calling the client returned by `make_client`.
Attributes:
NAME (str): A name for the endpoint, added to the path as well as used
in logging and metrics.
PATH_ARGS (tuple[str]): A list of parameters to be added to the path.
Adding parameters to the path (rather than payload) can make it
easier to follow along in the log files.
METHOD (str): The method of the HTTP request, defaults to POST. Can be
one of POST, PUT or GET. If GET then the payload is sent as query
parameters rather than a JSON body.
CACHE (bool): Whether server should cache the result of the request/
If true then transparently adds a txn_id to all requests, and
`_handle_request` must return a Deferred.
RETRY_ON_TIMEOUT(bool): Whether or not to retry the request when a 504
is received.
"""
__metaclass__ = abc.ABCMeta
NAME = abc.abstractproperty() # type: str # type: ignore
PATH_ARGS = abc.abstractproperty() # type: Tuple[str, ...] # type: ignore
METHOD = "POST"
CACHE = True
RETRY_ON_TIMEOUT = True
def __init__(self, hs):
if self.CACHE:
self.response_cache = ResponseCache(
hs, "repl." + self.NAME, timeout_ms=30 * 60 * 1000
)
assert self.METHOD in ("PUT", "POST", "GET")
@abc.abstractmethod
def _serialize_payload(**kwargs):
"""Static method that is called when creating a request.
Concrete implementations should have explicit parameters (rather than
kwargs) so that an appropriate exception is raised if the client is
called with unexpected parameters. All PATH_ARGS must appear in
argument list.
Returns:
Deferred[dict]|dict: If POST/PUT request then dictionary must be
JSON serialisable, otherwise must be appropriate for adding as
query args.
"""
return {}
@abc.abstractmethod
async def _handle_request(self, request, **kwargs):
"""Handle incoming request.
This is called with the request object and PATH_ARGS.
Returns:
tuple[int, dict]: HTTP status code and a JSON serialisable dict
to be used as response body of request.
"""
pass
@classmethod
def make_client(cls, hs):
"""Create a client that makes requests.
Returns a callable that accepts the same parameters as `_serialize_payload`.
"""
clock = hs.get_clock()
host = hs.config.worker_replication_host
port = hs.config.worker_replication_http_port
client = hs.get_simple_http_client()
@trace(opname="outgoing_replication_request")
@defer.inlineCallbacks
def send_request(**kwargs):
data = yield cls._serialize_payload(**kwargs)
url_args = [
urllib.parse.quote(kwargs[name], safe="") for name in cls.PATH_ARGS
]
if cls.CACHE:
txn_id = random_string(10)
url_args.append(txn_id)
if cls.METHOD == "POST":
request_func = client.post_json_get_json
elif cls.METHOD == "PUT":
request_func = client.put_json
elif cls.METHOD == "GET":
request_func = client.get_json
else:
# We have already asserted in the constructor that a
# compatible was picked, but lets be paranoid.
raise Exception(
"Unknown METHOD on %s replication endpoint" % (cls.NAME,)
)
uri = "http://%s:%s/_synapse/replication/%s/%s" % (
host,
port,
cls.NAME,
"/".join(url_args),
)
try:
# We keep retrying the same request for timeouts. This is so that we
# have a good idea that the request has either succeeded or failed on
# the master, and so whether we should clean up or not.
while True:
headers = {} # type: Dict[bytes, List[bytes]]
inject_active_span_byte_dict(headers, None, check_destination=False)
try:
result = yield request_func(uri, data, headers=headers)
break
except CodeMessageException as e:
if e.code != 504 or not cls.RETRY_ON_TIMEOUT:
raise
logger.warning("%s request timed out", cls.NAME)
# If we timed out we probably don't need to worry about backing
# off too much, but lets just wait a little anyway.
yield clock.sleep(1)
except HttpResponseException as e:
# We convert to SynapseError as we know that it was a SynapseError
# on the master process that we should send to the client. (And
# importantly, not stack traces everywhere)
raise e.to_synapse_error()
except RequestSendFailed as e:
raise_from(SynapseError(502, "Failed to talk to master"), e)
return result
return send_request
def register(self, http_server):
"""Called by the server to register this as a handler to the
appropriate path.
"""
url_args = list(self.PATH_ARGS)
handler = self._handle_request
method = self.METHOD
if self.CACHE:
handler = self._cached_handler # type: ignore
url_args.append("txn_id")
args = "/".join("(?P<%s>[^/]+)" % (arg,) for arg in url_args)
pattern = re.compile("^/_synapse/replication/%s/%s$" % (self.NAME, args))
handler = trace_servlet(self.__class__.__name__, extract_context=True)(handler)
# We don't let register paths trace this servlet using the default tracing
# options because we wish to extract the context explicitly.
http_server.register_paths(
method, [pattern], handler, self.__class__.__name__, trace=False
)
def _cached_handler(self, request, txn_id, **kwargs):
"""Called on new incoming requests when caching is enabled. Checks
if there is a cached response for the request and returns that,
otherwise calls `_handle_request` and caches its response.
"""
# We just use the txn_id here, but we probably also want to use the
# other PATH_ARGS as well.
assert self.CACHE
return self.response_cache.wrap(txn_id, self._handle_request, request, **kwargs)