Merge branch 'release-v1.13.0' of github.com:matrix-org/synapse into dinsic-release-v1.14.x

* 'release-v1.13.0' of github.com:matrix-org/synapse: (257 commits)
  Update changelog based on feedback.
  Move warnings in the changelog and re-iterate changes to branches.
  1.13.0
  update dh-virtualenv (#7526)
  1.13.0rc3
  Hash passwords earlier in the registration process (#7523)
  1.13.0rc2
  1.13.0rc2
  Stop `get_joined_users` corruption from custom statuses (#7376)
  Do not validate that the client dict is stable during UI Auth. (#7483)
  Fix new flake8 errors (#7489)
  Don't UPGRADE database rows
  RST indenting
  Put rollback instructions in upgrade notes
  Fix changelog typo
  Oh yeah, RST
  Absolute URL it is then
  Fix upgrade notes link
  Provide summary of upgrade issues in changelog. Fix )
  Move next version notes from changelog to upgrade notes
  ...

1 files changed, 18 insertions, 1 deletions

diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py

index 1be1ccbdf3..f88c80ae84 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -16,6 +16,7 @@
 import abc
 import logging
 import re
+from inspect import signature
 from typing import Dict, List, Tuple
 
 from six import raise_from
@@ -60,6 +61,8 @@ class ReplicationEndpoint(object):
     must call `register` to register the path with the HTTP server.
 
     Requests can be sent by calling the client returned by `make_client`.
+    Requests are sent to master process by default, but can be sent to other
+    named processes by specifying an `instance_name` keyword argument.
 
     Attributes:
         NAME (str): A name for the endpoint, added to the path as well as used
@@ -91,6 +94,16 @@ class ReplicationEndpoint(object):
                 hs, "repl." + self.NAME, timeout_ms=30 * 60 * 1000
             )
 
+        # We reserve `instance_name` as a parameter to sending requests, so we
+        # assert here that sub classes don't try and use the name.
+        assert (
+            "instance_name" not in self.PATH_ARGS
+        ), "`instance_name` is a reserved paramater name"
+        assert (
+            "instance_name"
+            not in signature(self.__class__._serialize_payload).parameters
+        ), "`instance_name` is a reserved paramater name"
+
         assert self.METHOD in ("PUT", "POST", "GET")
 
     @abc.abstractmethod
@@ -135,7 +148,11 @@ class ReplicationEndpoint(object):
 
         @trace(opname="outgoing_replication_request")
         @defer.inlineCallbacks
-        def send_request(**kwargs):
+        def send_request(instance_name="master", **kwargs):
+            # Currently we only support sending requests to master process.
+            if instance_name != "master":
+                raise Exception("Unknown instance")
+
             data = yield cls._serialize_payload(**kwargs)
 
             url_args = [