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authorPatrick Cloke <patrickc@matrix.org>2020-05-19 09:55:39 -0400
committerPatrick Cloke <patrickc@matrix.org>2020-05-19 09:55:39 -0400
commit13a82768ac4fdc1f5a24da9be5e51c5065382596 (patch)
treed14b2100876cde31e677d4f8a0db5036c882fcbe /synapse/replication/tcp/protocol.py
parentremove spurious changelog files (diff)
parentUpdate changelog based on feedback. (diff)
downloadsynapse-13a82768ac4fdc1f5a24da9be5e51c5065382596.tar.xz
Merge tag 'v1.13.0'
Synapse 1.13.0 (2020-05-19)
===========================

This release brings some potential changes necessary for certain
configurations of Synapse:

* If your Synapse is configured to use SSO and have a custom
  `sso_redirect_confirm_template_dir` configuration option set, you will need
  to duplicate the new `sso_auth_confirm.html`, `sso_auth_success.html` and
  `sso_account_deactivated.html` templates into that directory.
* Synapse plugins using the `complete_sso_login` method of
  `synapse.module_api.ModuleApi` should instead switch to the async/await
  version, `complete_sso_login_async`, which includes additional checks. The
  former version is now deprecated.
* A bug was introduced in Synapse 1.4.0 which could cause the room directory
  to be incomplete or empty if Synapse was upgraded directly from v1.2.1 or
  earlier, to versions between v1.4.0 and v1.12.x.

Please review [UPGRADE.rst](https://github.com/matrix-org/synapse/blob/master/UPGRADE.rst)
for more details on these changes and for general upgrade guidance.

Notice of change to the default `git` branch for Synapse
--------------------------------------------------------

With the release of Synapse 1.13.0, the default `git` branch for Synapse has
changed to `develop`, which is the development tip. This is more consistent with
common practice and modern `git` usage.

The `master` branch, which tracks the latest release, is still available. It is
recommended that developers and distributors who have scripts which run builds
using the default branch of Synapse should therefore consider pinning their
scripts to `master`.

Features
--------

- Extend the `web_client_location` option to accept an absolute URL to use as a redirect. Adds a warning when running the web client on the same hostname as homeserver. Contributed by Martin Milata. ([\#7006](https://github.com/matrix-org/synapse/issues/7006))
- Set `Referrer-Policy` header to `no-referrer` on media downloads. ([\#7009](https://github.com/matrix-org/synapse/issues/7009))
- Add support for running replication over Redis when using workers. ([\#7040](https://github.com/matrix-org/synapse/issues/7040), [\#7325](https://github.com/matrix-org/synapse/issues/7325), [\#7352](https://github.com/matrix-org/synapse/issues/7352), [\#7401](https://github.com/matrix-org/synapse/issues/7401), [\#7427](https://github.com/matrix-org/synapse/issues/7427), [\#7439](https://github.com/matrix-org/synapse/issues/7439), [\#7446](https://github.com/matrix-org/synapse/issues/7446), [\#7450](https://github.com/matrix-org/synapse/issues/7450), [\#7454](https://github.com/matrix-org/synapse/issues/7454))
- Admin API `POST /_synapse/admin/v1/join/<roomIdOrAlias>` to join users to a room like `auto_join_rooms` for creation of users. ([\#7051](https://github.com/matrix-org/synapse/issues/7051))
- Add options to prevent users from changing their profile or associated 3PIDs. ([\#7096](https://github.com/matrix-org/synapse/issues/7096))
- Support SSO in the user interactive authentication workflow. ([\#7102](https://github.com/matrix-org/synapse/issues/7102), [\#7186](https://github.com/matrix-org/synapse/issues/7186), [\#7279](https://github.com/matrix-org/synapse/issues/7279), [\#7343](https://github.com/matrix-org/synapse/issues/7343))
- Allow server admins to define and enforce a password policy ([MSC2000](https://github.com/matrix-org/matrix-doc/issues/2000)). ([\#7118](https://github.com/matrix-org/synapse/issues/7118))
- Improve the support for SSO authentication on the login fallback page. ([\#7152](https://github.com/matrix-org/synapse/issues/7152), [\#7235](https://github.com/matrix-org/synapse/issues/7235))
- Always whitelist the login fallback in the SSO configuration if `public_baseurl` is set. ([\#7153](https://github.com/matrix-org/synapse/issues/7153))
- Admin users are no longer required to be in a room to create an alias for it. ([\#7191](https://github.com/matrix-org/synapse/issues/7191))
- Require admin privileges to enable room encryption by default. This does not affect existing rooms. ([\#7230](https://github.com/matrix-org/synapse/issues/7230))
- Add a config option for specifying the value of the Accept-Language HTTP header when generating URL previews. ([\#7265](https://github.com/matrix-org/synapse/issues/7265))
- Allow `/requestToken` endpoints to hide the existence (or lack thereof) of 3PID associations on the homeserver. ([\#7315](https://github.com/matrix-org/synapse/issues/7315))
- Add a configuration setting to tweak the threshold for dummy events. ([\#7422](https://github.com/matrix-org/synapse/issues/7422))

Bugfixes
--------

- Don't attempt to use an invalid sqlite config if no database configuration is provided. Contributed by @nekatak. ([\#6573](https://github.com/matrix-org/synapse/issues/6573))
- Fix single-sign on with CAS systems: pass the same service URL when requesting the CAS ticket and when calling the `proxyValidate` URL. Contributed by @Naugrimm. ([\#6634](https://github.com/matrix-org/synapse/issues/6634))
- Fix missing field `default` when fetching user-defined push rules. ([\#6639](https://github.com/matrix-org/synapse/issues/6639))
- Improve error responses when accessing remote public room lists. ([\#6899](https://github.com/matrix-org/synapse/issues/6899), [\#7368](https://github.com/matrix-org/synapse/issues/7368))
- Transfer alias mappings on room upgrade. ([\#6946](https://github.com/matrix-org/synapse/issues/6946))
- Ensure that a user interactive authentication session is tied to a single request. ([\#7068](https://github.com/matrix-org/synapse/issues/7068), [\#7455](https://github.com/matrix-org/synapse/issues/7455))
- Fix a bug in the federation API which could cause occasional "Failed to get PDU" errors. ([\#7089](https://github.com/matrix-org/synapse/issues/7089))
- Return the proper error (`M_BAD_ALIAS`) when a non-existant canonical alias is provided. ([\#7109](https://github.com/matrix-org/synapse/issues/7109))
- Fix a bug which meant that groups updates were not correctly replicated between workers. ([\#7117](https://github.com/matrix-org/synapse/issues/7117))
- Fix starting workers when federation sending not split out. ([\#7133](https://github.com/matrix-org/synapse/issues/7133))
- Ensure `is_verified` is a boolean in responses to `GET /_matrix/client/r0/room_keys/keys`. Also warn the user if they forgot the `version` query param. ([\#7150](https://github.com/matrix-org/synapse/issues/7150))
- Fix error page being shown when a custom SAML handler attempted to redirect when processing an auth response. ([\#7151](https://github.com/matrix-org/synapse/issues/7151))
- Avoid importing `sqlite3` when using the postgres backend. Contributed by David Vo. ([\#7155](https://github.com/matrix-org/synapse/issues/7155))
- Fix excessive CPU usage by `prune_old_outbound_device_pokes` job. ([\#7159](https://github.com/matrix-org/synapse/issues/7159))
- Fix a bug which could cause outbound federation traffic to stop working if a client uploaded an incorrect e2e device signature. ([\#7177](https://github.com/matrix-org/synapse/issues/7177))
- Fix a bug which could cause incorrect 'cyclic dependency' error. ([\#7178](https://github.com/matrix-org/synapse/issues/7178))
- Fix a bug that could cause a user to be invited to a server notices (aka System Alerts) room without any notice being sent. ([\#7199](https://github.com/matrix-org/synapse/issues/7199))
- Fix some worker-mode replication handling not being correctly recorded in CPU usage stats. ([\#7203](https://github.com/matrix-org/synapse/issues/7203))
- Do not allow a deactivated user to login via SSO. ([\#7240](https://github.com/matrix-org/synapse/issues/7240), [\#7259](https://github.com/matrix-org/synapse/issues/7259))
- Fix --help command-line argument. ([\#7249](https://github.com/matrix-org/synapse/issues/7249))
- Fix room publish permissions not being checked on room creation. ([\#7260](https://github.com/matrix-org/synapse/issues/7260))
- Reject unknown session IDs during user interactive authentication instead of silently creating a new session. ([\#7268](https://github.com/matrix-org/synapse/issues/7268))
- Fix a SQL query introduced in Synapse 1.12.0 which could cause large amounts of logging to the postgres slow-query log. ([\#7274](https://github.com/matrix-org/synapse/issues/7274))
- Persist user interactive authentication sessions across workers and Synapse restarts. ([\#7302](https://github.com/matrix-org/synapse/issues/7302))
- Fixed backwards compatibility logic of the first value of `trusted_third_party_id_servers` being used for `account_threepid_delegates.email`, which occurs when the former, deprecated option is set and the latter is not. ([\#7316](https://github.com/matrix-org/synapse/issues/7316))
- Fix a bug where event updates might not be sent over replication to worker processes after the stream falls behind. ([\#7337](https://github.com/matrix-org/synapse/issues/7337), [\#7358](https://github.com/matrix-org/synapse/issues/7358))
- Fix bad error handling that would cause Synapse to crash if it's provided with a YAML configuration file that's either empty or doesn't parse into a key-value map. ([\#7341](https://github.com/matrix-org/synapse/issues/7341))
- Fix incorrect metrics reporting for `renew_attestations` background task. ([\#7344](https://github.com/matrix-org/synapse/issues/7344))
- Prevent non-federating rooms from appearing in responses to federated `POST /publicRoom` requests when a filter was included. ([\#7367](https://github.com/matrix-org/synapse/issues/7367))
- Fix a bug which would cause the room durectory to be incorrectly populated if Synapse was upgraded directly from v1.2.1 or earlier to v1.4.0 or later. Note that this fix does not apply retrospectively; see the [upgrade notes](UPGRADE.rst#upgrading-to-v1130) for more information. ([\#7387](https://github.com/matrix-org/synapse/issues/7387))
- Fix bug in `EventContext.deserialize`. ([\#7393](https://github.com/matrix-org/synapse/issues/7393))
- Fix a long-standing bug which could cause messages not to be sent over federation, when state events with state keys matching user IDs (such as custom user statuses) were received. ([\#7376](https://github.com/matrix-org/synapse/issues/7376))
- Restore compatibility with non-compliant clients during the user interactive authentication process, fixing a problem introduced in v1.13.0rc1. ([\#7483](https://github.com/matrix-org/synapse/issues/7483))
- Hash passwords as early as possible during registration. ([\#7523](https://github.com/matrix-org/synapse/issues/7523))

Improved Documentation
----------------------

- Update Debian installation instructions to recommend installing the `virtualenv` package instead of `python3-virtualenv`. ([\#6892](https://github.com/matrix-org/synapse/issues/6892))
- Improve the documentation for database configuration. ([\#6988](https://github.com/matrix-org/synapse/issues/6988))
- Improve the documentation of application service configuration files. ([\#7091](https://github.com/matrix-org/synapse/issues/7091))
- Update pre-built package name for FreeBSD. ([\#7107](https://github.com/matrix-org/synapse/issues/7107))
- Update postgres docs with login troubleshooting information. ([\#7119](https://github.com/matrix-org/synapse/issues/7119))
- Clean up INSTALL.md a bit. ([\#7141](https://github.com/matrix-org/synapse/issues/7141))
- Add documentation for running a local CAS server for testing. ([\#7147](https://github.com/matrix-org/synapse/issues/7147))
- Improve README.md by being explicit about public IP recommendation for TURN relaying. ([\#7167](https://github.com/matrix-org/synapse/issues/7167))
- Fix a small typo in the `metrics_flags` config option. ([\#7171](https://github.com/matrix-org/synapse/issues/7171))
- Update the contributed documentation on managing synapse workers with systemd, and bring it into the core distribution. ([\#7234](https://github.com/matrix-org/synapse/issues/7234))
- Add documentation to the `password_providers` config option. Add known password provider implementations to docs. ([\#7238](https://github.com/matrix-org/synapse/issues/7238), [\#7248](https://github.com/matrix-org/synapse/issues/7248))
- Modify suggested nginx reverse proxy configuration to match Synapse's default file upload size. Contributed by @ProCycleDev. ([\#7251](https://github.com/matrix-org/synapse/issues/7251))
- Documentation of media_storage_providers options updated to avoid misunderstandings. Contributed by Tristan Lins. ([\#7272](https://github.com/matrix-org/synapse/issues/7272))
- Add documentation on monitoring workers with Prometheus. ([\#7357](https://github.com/matrix-org/synapse/issues/7357))
- Clarify endpoint usage in the users admin api documentation. ([\#7361](https://github.com/matrix-org/synapse/issues/7361))

Deprecations and Removals
-------------------------

- Remove nonfunctional `captcha_bypass_secret` option from `homeserver.yaml`. ([\#7137](https://github.com/matrix-org/synapse/issues/7137))

Internal Changes
----------------

- Add benchmarks for LruCache. ([\#6446](https://github.com/matrix-org/synapse/issues/6446))
- Return total number of users and profile attributes in admin users endpoint. Contributed by Awesome Technologies Innovationslabor GmbH. ([\#6881](https://github.com/matrix-org/synapse/issues/6881))
- Change device list streams to have one row per ID. ([\#7010](https://github.com/matrix-org/synapse/issues/7010))
- Remove concept of a non-limited stream. ([\#7011](https://github.com/matrix-org/synapse/issues/7011))
- Move catchup of replication streams logic to worker. ([\#7024](https://github.com/matrix-org/synapse/issues/7024), [\#7195](https://github.com/matrix-org/synapse/issues/7195), [\#7226](https://github.com/matrix-org/synapse/issues/7226), [\#7239](https://github.com/matrix-org/synapse/issues/7239), [\#7286](https://github.com/matrix-org/synapse/issues/7286), [\#7290](https://github.com/matrix-org/synapse/issues/7290), [\#7318](https://github.com/matrix-org/synapse/issues/7318), [\#7326](https://github.com/matrix-org/synapse/issues/7326), [\#7378](https://github.com/matrix-org/synapse/issues/7378), [\#7421](https://github.com/matrix-org/synapse/issues/7421))
- Convert some of synapse.rest.media to async/await. ([\#7110](https://github.com/matrix-org/synapse/issues/7110), [\#7184](https://github.com/matrix-org/synapse/issues/7184), [\#7241](https://github.com/matrix-org/synapse/issues/7241))
- De-duplicate / remove unused REST code for login and auth. ([\#7115](https://github.com/matrix-org/synapse/issues/7115))
- Convert `*StreamRow` classes to inner classes. ([\#7116](https://github.com/matrix-org/synapse/issues/7116))
- Clean up some LoggingContext code. ([\#7120](https://github.com/matrix-org/synapse/issues/7120), [\#7181](https://github.com/matrix-org/synapse/issues/7181), [\#7183](https://github.com/matrix-org/synapse/issues/7183), [\#7408](https://github.com/matrix-org/synapse/issues/7408), [\#7426](https://github.com/matrix-org/synapse/issues/7426))
- Add explicit `instance_id` for USER_SYNC commands and remove implicit `conn_id` usage. ([\#7128](https://github.com/matrix-org/synapse/issues/7128))
- Refactored the CAS authentication logic to a separate class. ([\#7136](https://github.com/matrix-org/synapse/issues/7136))
- Run replication streamers on workers. ([\#7146](https://github.com/matrix-org/synapse/issues/7146))
- Add tests for outbound device pokes. ([\#7157](https://github.com/matrix-org/synapse/issues/7157))
- Fix device list update stream ids going backward. ([\#7158](https://github.com/matrix-org/synapse/issues/7158))
- Use `stream.current_token()` and remove `stream_positions()`. ([\#7172](https://github.com/matrix-org/synapse/issues/7172))
- Move client command handling out of TCP protocol. ([\#7185](https://github.com/matrix-org/synapse/issues/7185))
- Move server command handling out of TCP protocol. ([\#7187](https://github.com/matrix-org/synapse/issues/7187))
- Fix consistency of HTTP status codes reported in log lines. ([\#7188](https://github.com/matrix-org/synapse/issues/7188))
- Only run one background database update at a time. ([\#7190](https://github.com/matrix-org/synapse/issues/7190))
- Remove sent outbound device list pokes from the database. ([\#7192](https://github.com/matrix-org/synapse/issues/7192))
- Add a background database update job to clear out duplicate `device_lists_outbound_pokes`. ([\#7193](https://github.com/matrix-org/synapse/issues/7193))
- Remove some extraneous debugging log lines. ([\#7207](https://github.com/matrix-org/synapse/issues/7207))
- Add explicit Python build tooling as dependencies for the snapcraft build. ([\#7213](https://github.com/matrix-org/synapse/issues/7213))
- Add typing information to federation server code. ([\#7219](https://github.com/matrix-org/synapse/issues/7219))
- Extend room admin api (`GET /_synapse/admin/v1/rooms`) with additional attributes. ([\#7225](https://github.com/matrix-org/synapse/issues/7225))
- Unblacklist '/upgrade creates a new room' sytest for workers. ([\#7228](https://github.com/matrix-org/synapse/issues/7228))
- Remove redundant checks on `daemonize` from synctl. ([\#7233](https://github.com/matrix-org/synapse/issues/7233))
- Upgrade jQuery to v3.4.1 on fallback login/registration pages. ([\#7236](https://github.com/matrix-org/synapse/issues/7236))
- Change log line that told user to implement onLogin/onRegister fallback js functions to a warning, instead of an info, so it's more visible. ([\#7237](https://github.com/matrix-org/synapse/issues/7237))
- Correct the parameters of a test fixture. Contributed by Isaiah Singletary. ([\#7243](https://github.com/matrix-org/synapse/issues/7243))
- Convert auth handler to async/await. ([\#7261](https://github.com/matrix-org/synapse/issues/7261))
- Add some unit tests for replication. ([\#7278](https://github.com/matrix-org/synapse/issues/7278))
- Improve typing annotations in `synapse.replication.tcp.streams.Stream`. ([\#7291](https://github.com/matrix-org/synapse/issues/7291))
- Reduce log verbosity of url cache cleanup tasks. ([\#7295](https://github.com/matrix-org/synapse/issues/7295))
- Fix sample SAML Service Provider configuration. Contributed by @frcl. ([\#7300](https://github.com/matrix-org/synapse/issues/7300))
- Fix StreamChangeCache to work with multiple entities changing on the same stream id. ([\#7303](https://github.com/matrix-org/synapse/issues/7303))
- Fix an incorrect import in IdentityHandler. ([\#7319](https://github.com/matrix-org/synapse/issues/7319))
- Reduce logging verbosity for successful federation requests. ([\#7321](https://github.com/matrix-org/synapse/issues/7321))
- Convert some federation handler code to async/await. ([\#7338](https://github.com/matrix-org/synapse/issues/7338))
- Fix collation for postgres for unit tests. ([\#7359](https://github.com/matrix-org/synapse/issues/7359))
- Convert RegistrationWorkerStore.is_server_admin and dependent code to async/await. ([\#7363](https://github.com/matrix-org/synapse/issues/7363))
- Add an `instance_name` to `RDATA` and `POSITION` replication commands. ([\#7364](https://github.com/matrix-org/synapse/issues/7364))
- Thread through instance name to replication client. ([\#7369](https://github.com/matrix-org/synapse/issues/7369))
- Convert synapse.server_notices to async/await. ([\#7394](https://github.com/matrix-org/synapse/issues/7394))
- Convert synapse.notifier to async/await. ([\#7395](https://github.com/matrix-org/synapse/issues/7395))
- Fix issues with the Python package manifest. ([\#7404](https://github.com/matrix-org/synapse/issues/7404))
- Prevent methods in `synapse.handlers.auth` from polling the homeserver config every request. ([\#7420](https://github.com/matrix-org/synapse/issues/7420))
- Speed up fetching device lists changes when handling `/sync` requests. ([\#7423](https://github.com/matrix-org/synapse/issues/7423))
- Run group attestation renewal in series rather than parallel for performance. ([\#7442](https://github.com/matrix-org/synapse/issues/7442))
- Fix linting errors in new version of Flake8. ([\#7470](https://github.com/matrix-org/synapse/issues/7470))
- Update the version of dh-virtualenv we use to build debs, and add focal to the list of target distributions. ([\#7526](https://github.com/matrix-org/synapse/issues/7526))
Diffstat (limited to 'synapse/replication/tcp/protocol.py')
-rw-r--r--synapse/replication/tcp/protocol.py459
1 files changed, 88 insertions, 371 deletions
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index bc1482a9bb..4198eece71 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -35,9 +35,7 @@ indicate which side is sending, these are *not* included on the wire::
     > PING 1490197665618
     < NAME synapse.app.appservice
     < PING 1490197665618
-    < REPLICATE events 1
-    < REPLICATE backfill 1
-    < REPLICATE caches 1
+    < REPLICATE
     > POSITION events 1
     > POSITION backfill 1
     > POSITION caches 1
@@ -52,45 +50,51 @@ import abc
 import fcntl
 import logging
 import struct
-from collections import defaultdict
-from typing import Any, DefaultDict, Dict, List, Set, Tuple
-
-from six import iteritems, iterkeys
+from typing import TYPE_CHECKING, List
 
 from prometheus_client import Counter
 
-from twisted.internet import defer
 from twisted.protocols.basic import LineOnlyReceiver
 from twisted.python.failure import Failure
 
-from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.tcp.commands import (
-    COMMAND_MAP,
     VALID_CLIENT_COMMANDS,
     VALID_SERVER_COMMANDS,
     Command,
     ErrorCommand,
     NameCommand,
     PingCommand,
-    PositionCommand,
-    RdataCommand,
-    RemoteServerUpCommand,
     ReplicateCommand,
     ServerCommand,
-    SyncCommand,
-    UserSyncCommand,
+    parse_command_from_line,
 )
-from synapse.replication.tcp.streams import STREAMS_MAP
 from synapse.types import Collection
 from synapse.util import Clock
 from synapse.util.stringutils import random_string
 
+if TYPE_CHECKING:
+    from synapse.replication.tcp.handler import ReplicationCommandHandler
+    from synapse.server import HomeServer
+
+
 connection_close_counter = Counter(
     "synapse_replication_tcp_protocol_close_reason", "", ["reason_type"]
 )
 
+tcp_inbound_commands_counter = Counter(
+    "synapse_replication_tcp_protocol_inbound_commands",
+    "Number of commands received from replication, by command and name of process connected to",
+    ["command", "name"],
+)
+
+tcp_outbound_commands_counter = Counter(
+    "synapse_replication_tcp_protocol_outbound_commands",
+    "Number of commands sent to replication, by command and name of process connected to",
+    ["command", "name"],
+)
+
 # A list of all connected protocols. This allows us to send metrics about the
 # connections.
 connected_connections = []
@@ -119,7 +123,7 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
     are only sent by the server.
 
     On receiving a new command it calls `on_<COMMAND_NAME>` with the parsed
-    command.
+    command before delegating to `ReplicationCommandHandler.on_<COMMAND_NAME>`.
 
     It also sends `PING` periodically, and correctly times out remote connections
     (if they send a `PING` command)
@@ -135,8 +139,9 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
 
     max_line_buffer = 10000
 
-    def __init__(self, clock):
+    def __init__(self, clock: Clock, handler: "ReplicationCommandHandler"):
         self.clock = clock
+        self.command_handler = handler
 
         self.last_received_command = self.clock.time_msec()
         self.last_sent_command = 0
@@ -155,9 +160,6 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         # The LoopingCall for sending pings.
         self._send_ping_loop = None
 
-        self.inbound_commands_counter = defaultdict(int)  # type: DefaultDict[str, int]
-        self.outbound_commands_counter = defaultdict(int)  # type: DefaultDict[str, int]
-
     def connectionMade(self):
         logger.info("[%s] Connection established", self.id())
 
@@ -176,6 +178,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         # can time us out.
         self.send_command(PingCommand(self.clock.time_msec()))
 
+        self.command_handler.new_connection(self)
+
     def send_ping(self):
         """Periodically sends a ping and checks if we should close the connection
         due to the other side timing out.
@@ -203,38 +207,30 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
                 )
                 self.send_error("ping timeout")
 
-    def lineReceived(self, line):
+    def lineReceived(self, line: bytes):
         """Called when we've received a line
         """
         if line.strip() == "":
             # Ignore blank lines
             return
 
-        line = line.decode("utf-8")
-        cmd_name, rest_of_line = line.split(" ", 1)
+        linestr = line.decode("utf-8")
 
-        if cmd_name not in self.VALID_INBOUND_COMMANDS:
-            logger.error("[%s] invalid command %s", self.id(), cmd_name)
-            self.send_error("invalid command: %s", cmd_name)
+        try:
+            cmd = parse_command_from_line(linestr)
+        except Exception as e:
+            logger.exception("[%s] failed to parse line: %r", self.id(), linestr)
+            self.send_error("failed to parse line: %r (%r):" % (e, linestr))
             return
 
-        self.last_received_command = self.clock.time_msec()
+        if cmd.NAME not in self.VALID_INBOUND_COMMANDS:
+            logger.error("[%s] invalid command %s", self.id(), cmd.NAME)
+            self.send_error("invalid command: %s", cmd.NAME)
+            return
 
-        self.inbound_commands_counter[cmd_name] = (
-            self.inbound_commands_counter[cmd_name] + 1
-        )
+        self.last_received_command = self.clock.time_msec()
 
-        cmd_cls = COMMAND_MAP[cmd_name]
-        try:
-            cmd = cmd_cls.from_line(rest_of_line)
-        except Exception as e:
-            logger.exception(
-                "[%s] failed to parse line %r: %r", self.id(), cmd_name, rest_of_line
-            )
-            self.send_error(
-                "failed to parse line for  %r: %r (%r):" % (cmd_name, e, rest_of_line)
-            )
-            return
+        tcp_inbound_commands_counter.labels(cmd.NAME, self.name).inc()
 
         # Now lets try and call on_<CMD_NAME> function
         run_as_background_process(
@@ -244,13 +240,31 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
     async def handle_command(self, cmd: Command):
         """Handle a command we have received over the replication stream.
 
-        By default delegates to on_<COMMAND>, which should return an awaitable.
+        First calls `self.on_<COMMAND>` if it exists, then calls
+        `self.command_handler.on_<COMMAND>` if it exists. This allows for
+        protocol level handling of commands (e.g. PINGs), before delegating to
+        the handler.
 
         Args:
             cmd: received command
         """
-        handler = getattr(self, "on_%s" % (cmd.NAME,))
-        await handler(cmd)
+        handled = False
+
+        # First call any command handlers on this instance. These are for TCP
+        # specific handling.
+        cmd_func = getattr(self, "on_%s" % (cmd.NAME,), None)
+        if cmd_func:
+            await cmd_func(cmd)
+            handled = True
+
+        # Then call out to the handler.
+        cmd_func = getattr(self.command_handler, "on_%s" % (cmd.NAME,), None)
+        if cmd_func:
+            await cmd_func(self, cmd)
+            handled = True
+
+        if not handled:
+            logger.warning("Unhandled command: %r", cmd)
 
     def close(self):
         logger.warning("[%s] Closing connection", self.id())
@@ -282,9 +296,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
             self._queue_command(cmd)
             return
 
-        self.outbound_commands_counter[cmd.NAME] = (
-            self.outbound_commands_counter[cmd.NAME] + 1
-        )
+        tcp_outbound_commands_counter.labels(cmd.NAME, self.name).inc()
+
         string = "%s %s" % (cmd.NAME, cmd.to_line())
         if "\n" in string:
             raise Exception("Unexpected newline in command: %r", string)
@@ -379,6 +392,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         self.state = ConnectionStates.CLOSED
         self.pending_commands = []
 
+        self.command_handler.lost_connection(self)
+
         if self.transport:
             self.transport.unregisterProducer()
 
@@ -405,232 +420,21 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
     VALID_INBOUND_COMMANDS = VALID_CLIENT_COMMANDS
     VALID_OUTBOUND_COMMANDS = VALID_SERVER_COMMANDS
 
-    def __init__(self, server_name, clock, streamer):
-        BaseReplicationStreamProtocol.__init__(self, clock)  # Old style class
+    def __init__(
+        self, server_name: str, clock: Clock, handler: "ReplicationCommandHandler"
+    ):
+        super().__init__(clock, handler)
 
         self.server_name = server_name
-        self.streamer = streamer
-
-        # The streams the client has subscribed to and is up to date with
-        self.replication_streams = set()  # type: Set[str]
-
-        # The streams the client is currently subscribing to.
-        self.connecting_streams = set()  # type:  Set[str]
-
-        # Map from stream name to list of updates to send once we've finished
-        # subscribing the client to the stream.
-        self.pending_rdata = {}  # type: Dict[str, List[Tuple[int, Any]]]
 
     def connectionMade(self):
         self.send_command(ServerCommand(self.server_name))
-        BaseReplicationStreamProtocol.connectionMade(self)
-        self.streamer.new_connection(self)
+        super().connectionMade()
 
     async def on_NAME(self, cmd):
         logger.info("[%s] Renamed to %r", self.id(), cmd.data)
         self.name = cmd.data
 
-    async def on_USER_SYNC(self, cmd):
-        await self.streamer.on_user_sync(
-            self.conn_id, cmd.user_id, cmd.is_syncing, cmd.last_sync_ms
-        )
-
-    async def on_REPLICATE(self, cmd):
-        stream_name = cmd.stream_name
-        token = cmd.token
-
-        if stream_name == "ALL":
-            # Subscribe to all streams we're publishing to.
-            deferreds = [
-                run_in_background(self.subscribe_to_stream, stream, token)
-                for stream in iterkeys(self.streamer.streams_by_name)
-            ]
-
-            await make_deferred_yieldable(
-                defer.gatherResults(deferreds, consumeErrors=True)
-            )
-        else:
-            await self.subscribe_to_stream(stream_name, token)
-
-    async def on_FEDERATION_ACK(self, cmd):
-        self.streamer.federation_ack(cmd.token)
-
-    async def on_REMOVE_PUSHER(self, cmd):
-        await self.streamer.on_remove_pusher(cmd.app_id, cmd.push_key, cmd.user_id)
-
-    async def on_INVALIDATE_CACHE(self, cmd):
-        await self.streamer.on_invalidate_cache(cmd.cache_func, cmd.keys)
-
-    async def on_REMOTE_SERVER_UP(self, cmd: RemoteServerUpCommand):
-        self.streamer.on_remote_server_up(cmd.data)
-
-    async def on_USER_IP(self, cmd):
-        self.streamer.on_user_ip(
-            cmd.user_id,
-            cmd.access_token,
-            cmd.ip,
-            cmd.user_agent,
-            cmd.device_id,
-            cmd.last_seen,
-        )
-
-    async def subscribe_to_stream(self, stream_name, token):
-        """Subscribe the remote to a stream.
-
-        This invloves checking if they've missed anything and sending those
-        updates down if they have. During that time new updates for the stream
-        are queued and sent once we've sent down any missed updates.
-        """
-        self.replication_streams.discard(stream_name)
-        self.connecting_streams.add(stream_name)
-
-        try:
-            # Get missing updates
-            updates, current_token = await self.streamer.get_stream_updates(
-                stream_name, token
-            )
-
-            # Send all the missing updates
-            for update in updates:
-                token, row = update[0], update[1]
-                self.send_command(RdataCommand(stream_name, token, row))
-
-            # We send a POSITION command to ensure that they have an up to
-            # date token (especially useful if we didn't send any updates
-            # above)
-            self.send_command(PositionCommand(stream_name, current_token))
-
-            # Now we can send any updates that came in while we were subscribing
-            pending_rdata = self.pending_rdata.pop(stream_name, [])
-            updates = []
-            for token, update in pending_rdata:
-                # If the token is null, it is part of a batch update. Batches
-                # are multiple updates that share a single token. To denote
-                # this, the token is set to None for all tokens in the batch
-                # except for the last. If we find a None token, we keep looking
-                # through tokens until we find one that is not None and then
-                # process all previous updates in the batch as if they had the
-                # final token.
-                if token is None:
-                    # Store this update as part of a batch
-                    updates.append(update)
-                    continue
-
-                if token <= current_token:
-                    # This update or batch of updates is older than
-                    # current_token, dismiss it
-                    updates = []
-                    continue
-
-                updates.append(update)
-
-                # Send all updates that are part of this batch with the
-                # found token
-                for update in updates:
-                    self.send_command(RdataCommand(stream_name, token, update))
-
-                # Clear stored updates
-                updates = []
-
-            # They're now fully subscribed
-            self.replication_streams.add(stream_name)
-        except Exception as e:
-            logger.exception("[%s] Failed to handle REPLICATE command", self.id())
-            self.send_error("failed to handle replicate: %r", e)
-        finally:
-            self.connecting_streams.discard(stream_name)
-
-    def stream_update(self, stream_name, token, data):
-        """Called when a new update is available to stream to clients.
-
-        We need to check if the client is interested in the stream or not
-        """
-        if stream_name in self.replication_streams:
-            # The client is subscribed to the stream
-            self.send_command(RdataCommand(stream_name, token, data))
-        elif stream_name in self.connecting_streams:
-            # The client is being subscribed to the stream
-            logger.debug("[%s] Queuing RDATA %r %r", self.id(), stream_name, token)
-            self.pending_rdata.setdefault(stream_name, []).append((token, data))
-        else:
-            # The client isn't subscribed
-            logger.debug("[%s] Dropping RDATA %r %r", self.id(), stream_name, token)
-
-    def send_sync(self, data):
-        self.send_command(SyncCommand(data))
-
-    def send_remote_server_up(self, server: str):
-        self.send_command(RemoteServerUpCommand(server))
-
-    def on_connection_closed(self):
-        BaseReplicationStreamProtocol.on_connection_closed(self)
-        self.streamer.lost_connection(self)
-
-
-class AbstractReplicationClientHandler(metaclass=abc.ABCMeta):
-    """
-    The interface for the handler that should be passed to
-    ClientReplicationStreamProtocol
-    """
-
-    @abc.abstractmethod
-    async def on_rdata(self, stream_name, token, rows):
-        """Called to handle a batch of replication data with a given stream token.
-
-        Args:
-            stream_name (str): name of the replication stream for this batch of rows
-            token (int): stream token for this batch of rows
-            rows (list): a list of Stream.ROW_TYPE objects as returned by
-                Stream.parse_row.
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    async def on_position(self, stream_name, token):
-        """Called when we get new position data."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def on_sync(self, data):
-        """Called when get a new SYNC command."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    async def on_remote_server_up(self, server: str):
-        """Called when get a new REMOTE_SERVER_UP command."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def get_streams_to_replicate(self):
-        """Called when a new connection has been established and we need to
-        subscribe to streams.
-
-        Returns:
-            map from stream name to the most recent update we have for
-            that stream (ie, the point we want to start replicating from)
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def get_currently_syncing_users(self):
-        """Get the list of currently syncing users (if any). This is called
-        when a connection has been established and we need to send the
-        currently syncing users."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def update_connection(self, connection):
-        """Called when a connection has been established (or lost with None).
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def finished_connecting(self):
-        """Called when we have successfully subscribed and caught up to all
-        streams we're interested in.
-        """
-        raise NotImplementedError()
-
 
 class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
     VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS
@@ -638,110 +442,51 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
 
     def __init__(
         self,
+        hs: "HomeServer",
         client_name: str,
         server_name: str,
         clock: Clock,
-        handler: AbstractReplicationClientHandler,
+        command_handler: "ReplicationCommandHandler",
     ):
-        BaseReplicationStreamProtocol.__init__(self, clock)
+        super().__init__(clock, command_handler)
 
         self.client_name = client_name
         self.server_name = server_name
-        self.handler = handler
-
-        # Set of stream names that have been subscribe to, but haven't yet
-        # caught up with. This is used to track when the client has been fully
-        # connected to the remote.
-        self.streams_connecting = set()  # type: Set[str]
-
-        # Map of stream to batched updates. See RdataCommand for info on how
-        # batching works.
-        self.pending_batches = {}  # type: Dict[str, Any]
 
     def connectionMade(self):
         self.send_command(NameCommand(self.client_name))
-        BaseReplicationStreamProtocol.connectionMade(self)
+        super().connectionMade()
 
         # Once we've connected subscribe to the necessary streams
-        for stream_name, token in iteritems(self.handler.get_streams_to_replicate()):
-            self.replicate(stream_name, token)
-
-        # Tell the server if we have any users currently syncing (should only
-        # happen on synchrotrons)
-        currently_syncing = self.handler.get_currently_syncing_users()
-        now = self.clock.time_msec()
-        for user_id in currently_syncing:
-            self.send_command(UserSyncCommand(user_id, True, now))
-
-        # We've now finished connecting to so inform the client handler
-        self.handler.update_connection(self)
-
-        # This will happen if we don't actually subscribe to any streams
-        if not self.streams_connecting:
-            self.handler.finished_connecting()
+        self.replicate()
 
     async def on_SERVER(self, cmd):
         if cmd.data != self.server_name:
             logger.error("[%s] Connected to wrong remote: %r", self.id(), cmd.data)
             self.send_error("Wrong remote")
 
-    async def on_RDATA(self, cmd):
-        stream_name = cmd.stream_name
-        inbound_rdata_count.labels(stream_name).inc()
-
-        try:
-            row = STREAMS_MAP[stream_name].parse_row(cmd.row)
-        except Exception:
-            logger.exception(
-                "[%s] Failed to parse RDATA: %r %r", self.id(), stream_name, cmd.row
-            )
-            raise
-
-        if cmd.token is None:
-            # I.e. this is part of a batch of updates for this stream. Batch
-            # until we get an update for the stream with a non None token
-            self.pending_batches.setdefault(stream_name, []).append(row)
-        else:
-            # Check if this is the last of a batch of updates
-            rows = self.pending_batches.pop(stream_name, [])
-            rows.append(row)
-            await self.handler.on_rdata(stream_name, cmd.token, rows)
-
-    async def on_POSITION(self, cmd):
-        # When we get a `POSITION` command it means we've finished getting
-        # missing updates for the given stream, and are now up to date.
-        self.streams_connecting.discard(cmd.stream_name)
-        if not self.streams_connecting:
-            self.handler.finished_connecting()
+    def replicate(self):
+        """Send the subscription request to the server
+        """
+        logger.info("[%s] Subscribing to replication streams", self.id())
 
-        await self.handler.on_position(cmd.stream_name, cmd.token)
+        self.send_command(ReplicateCommand())
 
-    async def on_SYNC(self, cmd):
-        self.handler.on_sync(cmd.data)
 
-    async def on_REMOTE_SERVER_UP(self, cmd: RemoteServerUpCommand):
-        self.handler.on_remote_server_up(cmd.data)
+class AbstractConnection(abc.ABC):
+    """An interface for replication connections.
+    """
 
-    def replicate(self, stream_name, token):
-        """Send the subscription request to the server
+    @abc.abstractmethod
+    def send_command(self, cmd: Command):
+        """Send the command down the connection
         """
-        if stream_name not in STREAMS_MAP:
-            raise Exception("Invalid stream name %r" % (stream_name,))
-
-        logger.info(
-            "[%s] Subscribing to replication stream: %r from %r",
-            self.id(),
-            stream_name,
-            token,
-        )
-
-        self.streams_connecting.add(stream_name)
+        pass
 
-        self.send_command(ReplicateCommand(stream_name, token))
 
-    def on_connection_closed(self):
-        BaseReplicationStreamProtocol.on_connection_closed(self)
-        self.handler.update_connection(None)
+# This tells python that `BaseReplicationStreamProtocol` implements the
+# interface.
+AbstractConnection.register(BaseReplicationStreamProtocol)
 
 
 # The following simply registers metrics for the replication connections
@@ -804,31 +549,3 @@ tcp_transport_kernel_read_buffer = LaterGauge(
         for p in connected_connections
     },
 )
-
-
-tcp_inbound_commands = LaterGauge(
-    "synapse_replication_tcp_protocol_inbound_commands",
-    "",
-    ["command", "name"],
-    lambda: {
-        (k, p.name): count
-        for p in connected_connections
-        for k, count in iteritems(p.inbound_commands_counter)
-    },
-)
-
-tcp_outbound_commands = LaterGauge(
-    "synapse_replication_tcp_protocol_outbound_commands",
-    "",
-    ["command", "name"],
-    lambda: {
-        (k, p.name): count
-        for p in connected_connections
-        for k, count in iteritems(p.outbound_commands_counter)
-    },
-)
-
-# number of updates received for each RDATA stream
-inbound_rdata_count = Counter(
-    "synapse_replication_tcp_protocol_inbound_rdata_count", "", ["stream_name"]
-)