MatrixSynapse/synapse/http/replicationagent.py

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# Copyright 2023 The Matrix.org Foundation C.I.C.
#
# 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
from typing import Dict, Optional
from zope.interface import implementer
from twisted.internet import defer
from twisted.internet.endpoints import (
HostnameEndpoint,
UNIXClientEndpoint,
wrapClientTLS,
)
from twisted.internet.interfaces import IStreamClientEndpoint
from twisted.python.failure import Failure
from twisted.web.client import URI, HTTPConnectionPool, _AgentBase
from twisted.web.error import SchemeNotSupported
from twisted.web.http_headers import Headers
from twisted.web.iweb import (
IAgent,
IAgentEndpointFactory,
IBodyProducer,
IPolicyForHTTPS,
IResponse,
)
from synapse.config.workers import (
InstanceLocationConfig,
InstanceTcpLocationConfig,
InstanceUnixLocationConfig,
)
from synapse.types import ISynapseReactor
logger = logging.getLogger(__name__)
@implementer(IAgentEndpointFactory)
class ReplicationEndpointFactory:
"""Connect to a given TCP or UNIX socket"""
def __init__(
self,
reactor: ISynapseReactor,
instance_map: Dict[str, InstanceLocationConfig],
context_factory: IPolicyForHTTPS,
) -> None:
self.reactor = reactor
self.instance_map = instance_map
self.context_factory = context_factory
def endpointForURI(self, uri: URI) -> IStreamClientEndpoint:
"""
This part of the factory decides what kind of endpoint is being connected to.
Args:
uri: The pre-parsed URI object containing all the uri data
Returns: The correct client endpoint object
"""
# The given URI has a special scheme and includes the worker name. The
# actual connection details are pulled from the instance map.
worker_name = uri.netloc.decode("utf-8")
location_config = self.instance_map[worker_name]
scheme = location_config.scheme()
if isinstance(location_config, InstanceTcpLocationConfig):
endpoint = HostnameEndpoint(
self.reactor,
location_config.host,
location_config.port,
)
if scheme == "https":
endpoint = wrapClientTLS(
# The 'port' argument below isn't actually used by the function
self.context_factory.creatorForNetloc(
location_config.host.encode("utf-8"),
location_config.port,
),
endpoint,
)
return endpoint
elif isinstance(location_config, InstanceUnixLocationConfig):
return UNIXClientEndpoint(self.reactor, location_config.path)
else:
raise SchemeNotSupported(f"Unsupported scheme: {scheme}")
@implementer(IAgent)
class ReplicationAgent(_AgentBase):
"""
Client for connecting to replication endpoints via HTTP and HTTPS.
Much of this code is copied from Twisted's twisted.web.client.Agent.
"""
def __init__(
self,
reactor: ISynapseReactor,
instance_map: Dict[str, InstanceLocationConfig],
contextFactory: IPolicyForHTTPS,
connectTimeout: Optional[float] = None,
bindAddress: Optional[bytes] = None,
pool: Optional[HTTPConnectionPool] = None,
):
"""
Create a ReplicationAgent.
Args:
reactor: A reactor for this Agent to place outgoing connections.
contextFactory: A factory for TLS contexts, to control the
verification parameters of OpenSSL. The default is to use a
BrowserLikePolicyForHTTPS, so unless you have special
requirements you can leave this as-is.
connectTimeout: The amount of time that this Agent will wait
for the peer to accept a connection.
bindAddress: The local address for client sockets to bind to.
pool: An HTTPConnectionPool instance, or None, in which
case a non-persistent HTTPConnectionPool instance will be
created.
"""
_AgentBase.__init__(self, reactor, pool)
endpoint_factory = ReplicationEndpointFactory(
reactor, instance_map, contextFactory
)
self._endpointFactory = endpoint_factory
def request(
self,
method: bytes,
uri: bytes,
headers: Optional[Headers] = None,
bodyProducer: Optional[IBodyProducer] = None,
) -> "defer.Deferred[IResponse]":
"""
Issue a request to the server indicated by the given uri.
An existing connection from the connection pool may be used or a new
one may be created.
Currently, HTTP, HTTPS and UNIX schemes are supported in uri.
This is copied from twisted.web.client.Agent, except:
* It uses a different pool key (combining the scheme with either host & port or
socket path).
* It does not call _ensureValidURI(...) as the strictness of IDNA2008 is not
required when using a worker's name as a 'hostname' for Synapse HTTP
Replication machinery. Specifically, this allows a range of ascii characters
such as '+' and '_' in hostnames/worker's names.
See: twisted.web.iweb.IAgent.request
"""
parsedURI = URI.fromBytes(uri)
try:
endpoint = self._endpointFactory.endpointForURI(parsedURI)
except SchemeNotSupported:
return defer.fail(Failure())
worker_name = parsedURI.netloc.decode("utf-8")
key_scheme = self._endpointFactory.instance_map[worker_name].scheme()
key_netloc = self._endpointFactory.instance_map[worker_name].netloc()
# This sets the Pool key to be:
# (http(s), <host:port>) or (unix, <socket_path>)
key = (key_scheme, key_netloc)
# _requestWithEndpoint comes from _AgentBase class
return self._requestWithEndpoint(
key,
endpoint,
method,
parsedURI,
headers,
bodyProducer,
parsedURI.originForm,
)