Revert "Federation outbound proxy" (#15910)

Revert "Federation outbound proxy (#15773)"

This reverts commit b07b14b494ae1dd564b4c44f844c9a9545b3d08a.

1 files changed, 2 insertions, 77 deletions

diff --git a/synapse/http/proxyagent.py b/synapse/http/proxyagent.py
index 1fa3adbef2..7bdc4acae7 100644
--- a/synapse/http/proxyagent.py
+++ b/synapse/http/proxyagent.py
@@ -12,9 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-import random
 import re
-from typing import Any, Collection, Dict, List, Optional, Sequence, Tuple
+from typing import Any, Dict, Optional, Tuple
 from urllib.parse import urlparse
 from urllib.request import (  # type: ignore[attr-defined]
     getproxies_environment,
@@ -25,12 +24,7 @@ from zope.interface import implementer
 
 from twisted.internet import defer
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.internet.interfaces import (
-    IProtocol,
-    IProtocolFactory,
-    IReactorCore,
-    IStreamClientEndpoint,
-)
+from twisted.internet.interfaces import IReactorCore, IStreamClientEndpoint
 from twisted.python.failure import Failure
 from twisted.web.client import (
     URI,
@@ -42,10 +36,8 @@ from twisted.web.error import SchemeNotSupported
 from twisted.web.http_headers import Headers
 from twisted.web.iweb import IAgent, IBodyProducer, IPolicyForHTTPS, IResponse
 
-from synapse.config.workers import InstanceLocationConfig
 from synapse.http import redact_uri
 from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint, ProxyCredentials
-from synapse.logging.context import run_in_background
 
 logger = logging.getLogger(__name__)
 
@@ -82,10 +74,6 @@ class ProxyAgent(_AgentBase):
         use_proxy: Whether proxy settings should be discovered and used
             from conventional environment variables.
 
-        federation_proxies: An optional list of locations to proxy outbound federation
-            traffic through (only requests that use the `matrix-federation://` scheme
-            will be proxied).
-
     Raises:
         ValueError if use_proxy is set and the environment variables
             contain an invalid proxy specification.
@@ -101,7 +89,6 @@ class ProxyAgent(_AgentBase):
         bindAddress: Optional[bytes] = None,
         pool: Optional[HTTPConnectionPool] = None,
         use_proxy: bool = False,
-        federation_proxies: Collection[InstanceLocationConfig] = (),
     ):
         contextFactory = contextFactory or BrowserLikePolicyForHTTPS()
 
@@ -140,27 +127,6 @@ class ProxyAgent(_AgentBase):
         self._policy_for_https = contextFactory
         self._reactor = reactor
 
-        self._federation_proxy_endpoint: Optional[IStreamClientEndpoint] = None
-        if federation_proxies:
-            endpoints = []
-            for federation_proxy in federation_proxies:
-                endpoint = HostnameEndpoint(
-                    self.proxy_reactor,
-                    federation_proxy.host,
-                    federation_proxy.port,
-                )
-
-                if federation_proxy.tls:
-                    tls_connection_creator = self._policy_for_https.creatorForNetloc(
-                        federation_proxy.host,
-                        federation_proxy.port,
-                    )
-                    endpoint = wrapClientTLS(tls_connection_creator, endpoint)
-
-                endpoints.append(endpoint)
-
-            self._federation_proxy_endpoint = _ProxyEndpoints(endpoints)
-
     def request(
         self,
         method: bytes,
@@ -248,14 +214,6 @@ class ProxyAgent(_AgentBase):
                 parsed_uri.port,
                 self.https_proxy_creds,
             )
-        elif (
-            parsed_uri.scheme == b"matrix-federation"
-            and self._federation_proxy_endpoint
-        ):
-            # Cache *all* connections under the same key, since we are only
-            # connecting to a single destination, the proxy:
-            endpoint = self._federation_proxy_endpoint
-            request_path = uri
         else:
             # not using a proxy
             endpoint = HostnameEndpoint(
@@ -275,11 +233,6 @@ class ProxyAgent(_AgentBase):
             endpoint = wrapClientTLS(tls_connection_creator, endpoint)
         elif parsed_uri.scheme == b"http":
             pass
-        elif (
-            parsed_uri.scheme == b"matrix-federation"
-            and self._federation_proxy_endpoint
-        ):
-            pass
         else:
             return defer.fail(
                 Failure(
@@ -384,31 +337,3 @@ def parse_proxy(
         credentials = ProxyCredentials(b"".join([url.username, b":", url.password]))
 
     return url.scheme, url.hostname, url.port or default_port, credentials
-
-
-@implementer(IStreamClientEndpoint)
-class _ProxyEndpoints:
-    """An endpoint that randomly iterates through a given list of endpoints at
-    each connection attempt.
-    """
-
-    def __init__(self, endpoints: Sequence[IStreamClientEndpoint]) -> None:
-        assert endpoints
-        self._endpoints = endpoints
-
-    def connect(
-        self, protocol_factory: IProtocolFactory
-    ) -> "defer.Deferred[IProtocol]":
-        """Implements IStreamClientEndpoint interface"""
-
-        return run_in_background(self._do_connect, protocol_factory)
-
-    async def _do_connect(self, protocol_factory: IProtocolFactory) -> IProtocol:
-        failures: List[Failure] = []
-        for endpoint in random.sample(self._endpoints, k=len(self._endpoints)):
-            try:
-                return await endpoint.connect(protocol_factory)
-            except Exception:
-                failures.append(Failure())
-
-        failures.pop().raiseException()