Add redis support

mypy.ini

@@ -75,3 +75,6 @@ ignore_missing_imports = True
 
 [mypy-jwt.*]
 ignore_missing_imports = True
+
+[mypy-txredisapi]
+ignore_missing_imports = True

synapse/app/generic_worker.py

@@ -599,10 +599,19 @@ def start_listening(self, listeners):
             else:
                 logger.warning("Unrecognized listener type: %s", listener["type"])
 
-        factory = ReplicationClientFactory(self, self.config.worker_name)
-        host = self.config.worker_replication_host
-        port = self.config.worker_replication_port
-        self.get_reactor().connectTCP(host, port, factory)
+        if self.config.redis.redis_enabled:
+            from synapse.replication.tcp.redis import RedisFactory
+
+            logger.info("Connecting to redis.")
+            factory = RedisFactory(self)
+            self.get_reactor().connectTCP(
+                self.config.redis.redis_host, self.config.redis.redis_port, factory
+            )
+        else:
+            factory = ReplicationClientFactory(self, self.config.worker_name)
+            host = self.config.worker_replication_host
+            port = self.config.worker_replication_port
+            self.get_reactor().connectTCP(host, port, factory)
 
     def remove_pusher(self, app_id, push_key, user_id):
         self.get_tcp_replication().send_remove_pusher(app_id, push_key, user_id)

synapse/app/homeserver.py

@@ -263,6 +263,15 @@ def _configure_named_resource(self, name, compress=False):
     def start_listening(self, listeners):
         config = self.get_config()
 
+        if config.redis_enabled:
+            from synapse.replication.tcp.redis import RedisFactory
+
+            logger.info("Connecting to redis.")
+            factory = RedisFactory(self)
+            self.get_reactor().connectTCP(
+                self.config.redis.redis_host, self.config.redis.redis_port, factory
+            )
+
         for listener in listeners:
             if listener["type"] == "http":
                 self._listening_services.extend(self._listener_http(config, listener))
@@ -282,6 +291,7 @@ def start_listening(self, listeners):
                 )
                 for s in services:
                     reactor.addSystemEventTrigger("before", "shutdown", s.stopListening)
+
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
                     logger.warning(

synapse/config/homeserver.py

@@ -31,6 +31,7 @@
 from .password_auth_providers import PasswordAuthProviderConfig
 from .push import PushConfig
 from .ratelimiting import RatelimitConfig
+from .redis import RedisConfig
 from .registration import RegistrationConfig
 from .repository import ContentRepositoryConfig
 from .room_directory import RoomDirectoryConfig
@@ -82,4 +83,5 @@ class HomeServerConfig(RootConfig):
         RoomDirectoryConfig,
         ThirdPartyRulesConfig,
         TracerConfig,
+        RedisConfig,
     ]

synapse/config/redis.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 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.
+
+from synapse.config._base import Config, ConfigError
+
+try:
+    import txredisapi
+except ImportError:
+    txredisapi = None
+
+
+MISSING_REDIS = """Missing 'txredisapi' library. This is required for redis support.
+
+    Install by running:
+        pip install txredisapi
+"""
+
+
+class RedisConfig(Config):
+    section = "redis"
+
+    def read_config(self, config, **kwargs):
+        redis_config = config.get("redis", {})
+        self.redis_enabled = redis_config.get("enabled", False)
+
+        if not self.redis_enabled:
+            return
+
+        if txredisapi is None:
+            raise ConfigError(MISSING_REDIS)
+
+        self.redis_host = redis_config.get("host", "localhost")
+        self.redis_port = redis_config.get("port", 6379)
+        self.redis_dbid = redis_config.get("dbid")
+        self.redis_password = redis_config.get("password")

synapse/python_dependencies.py

@@ -98,6 +98,7 @@
     "sentry": ["sentry-sdk>=0.7.2"],
     "opentracing": ["jaeger-client>=4.0.0", "opentracing>=2.2.0"],
     "jwt": ["pyjwt>=1.6.4"],
+    "redis": ["txredisapi>=1.4.7"],
 }
 
 ALL_OPTIONAL_REQUIREMENTS = set()  # type: Set[str]

synapse/replication/tcp/redis.py

@@ -0,0 +1,158 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 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
+
+import txredisapi
+
+from synapse.logging.context import PreserveLoggingContext
+from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.replication.tcp.commands import (
+    COMMAND_MAP,
+    Command,
+    RdataCommand,
+    ReplicateCommand,
+)
+from synapse.util.stringutils import random_string
+
+logger = logging.getLogger(__name__)
+
+
+class RedisSubscriber(txredisapi.SubscriberProtocol):
+    """Connection to redis subscribed to replication stream.
+    """
+
+    def connectionMade(self):
+        logger.info("Connected to redis instance")
+        self.subscribe(self.stream_name)
+        self.send_command(ReplicateCommand())
+
+        self.handler.new_connection(self)
+
+    def messageReceived(self, pattern: str, channel: str, message: str):
+        """Received a message from redis.
+        """
+
+        if message.strip() == "":
+            # Ignore blank lines
+            return
+
+        line = message
+        cmd_name, rest_of_line = line.split(" ", 1)
+
+        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
+
+        # Now lets try and call on_<CMD_NAME> function
+        run_as_background_process(
+            "replication-" + cmd.get_logcontext_id(), self.handle_command, cmd
+        )
+
+    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.
+
+        Args:
+            cmd: received command
+        """
+        handled = False
+
+        # First call any command handlers on this instance. These are for redis
+        # 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.handler, "on_%s" % (cmd.NAME,), None)
+        if cmd_func:
+            await cmd_func(cmd)
+            handled = True
+
+        if not handled:
+            logger.warning("Unhandled command: %r", cmd)
+
+    def connectionLost(self, reason):
+        logger.info("Lost connection to redis instance")
+        self.handler.lost_connection(self)
+
+    def send_command(self, cmd):
+        """Send a command if connection has been established.
+
+        Args:
+            cmd (Command)
+        """
+        string = "%s %s" % (cmd.NAME, cmd.to_line())
+        if "\n" in string:
+            raise Exception("Unexpected newline in command: %r", string)
+
+        encoded_string = string.encode("utf-8")
+
+        async def _send():
+            with PreserveLoggingContext():
+                await self.redis_connection.publish(self.stream_name, encoded_string)
+
+        run_as_background_process("send-cmd", _send)
+
+    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
+        """
+        self.send_command(RdataCommand(stream_name, token, data))
+
+
+class RedisFactory(txredisapi.SubscriberFactory):
+
+    maxDelay = 5
+    continueTrying = True
+    protocol = RedisSubscriber
+
+    def __init__(self, hs):
+        super(RedisFactory, self).__init__()
+
+        self.password = hs.config.redis.redis_password
+
+        self.handler = hs.get_tcp_replication()
+        self.stream_name = hs.hostname
+
+        self.redis_connection = txredisapi.lazyConnection(
+            host=hs.config.redis_host,
+            port=hs.config.redis_port,
+            dbid=hs.config.redis_dbid,
+            password=hs.config.redis.redis_password,
+            reconnect=True,
+        )
+
+        self.conn_id = random_string(5)
+
+    def buildProtocol(self, addr):
+        p = super(RedisFactory, self).buildProtocol(addr)
+        p.handler = self.handler
+        p.redis_connection = self.redis_connection
+        p.conn_id = self.conn_id
+        p.stream_name = self.stream_name
+        return p