diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/replication/tcp/resource.py | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py new file mode 100644 index 0000000000..d5da0496a8 --- /dev/null +++ b/synapse/replication/tcp/resource.py @@ -0,0 +1,300 @@ +# -*- coding: utf-8 -*- +# Copyright 2017 Vector Creations Ltd +# +# 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. +"""The server side of the replication stream. +""" + +from twisted.internet import defer, reactor +from twisted.internet.protocol import Factory + +from streams import STREAMS_MAP, FederationStream +from protocol import ServerReplicationStreamProtocol + +from synapse.util.logcontext import preserve_fn +from synapse.util.metrics import Measure, measure_func + +import logging +import synapse.metrics + + +metrics = synapse.metrics.get_metrics_for(__name__) +stream_updates_counter = metrics.register_counter( + "stream_updates", labels=["stream_name"] +) +user_sync_counter = metrics.register_counter("user_sync") +federation_ack_counter = metrics.register_counter("federation_ack") +remove_pusher_counter = metrics.register_counter("remove_pusher") +invalidate_cache_counter = metrics.register_counter("invalidate_cache") + +logger = logging.getLogger(__name__) + + +class ReplicationStreamProtocolFactory(Factory): + """Factory for new replication connections. + """ + def __init__(self, hs): + self.streamer = ReplicationStreamer(hs) + self.clock = hs.get_clock() + self.server_name = hs.config.server_name + + def buildProtocol(self, addr): + return ServerReplicationStreamProtocol( + self.server_name, + self.clock, + self.streamer, + addr + ) + + +class ReplicationStreamer(object): + """Handles replication connections. + + This needs to be poked when new replication data may be available. When new + data is available it will propagate to all connected clients. + """ + + def __init__(self, hs): + self.store = hs.get_datastore() + self.notifier = hs.get_notifier() + self.presence_handler = hs.get_presence_handler() + self.clock = hs.get_clock() + + # Current connections. + self.connections = [] + + metrics.register_callback("total_connections", lambda: len(self.connections)) + + # List of streams that clients can subscribe to. + # We only support federation stream if federation sending hase been + # disabled on the master. + self.streams = [ + stream(hs) for stream in STREAMS_MAP.itervalues() + if stream != FederationStream or not hs.config.send_federation + ] + + self.streams_by_name = {stream.NAME: stream for stream in self.streams} + + metrics.register_callback( + "connections_per_stream", + lambda: { + (stream_name,): len([ + conn for conn in self.connections + if stream_name in conn.replication_streams + ]) + for stream_name in self.streams_by_name + }, + labels=["stream_name"], + ) + + self.federation_sender = None + if not hs.config.send_federation: + self.federation_sender = hs.get_federation_sender() + + # Start listening for updates from the notifier + preserve_fn(self.notifier_listener)() + + # Keeps track of whether we are currently checking for updates + self.is_looping = False + self.pending_updates = False + + reactor.addSystemEventTrigger("before", "shutdown", self.on_shutdown) + + def on_shutdown(self): + # close all connections on shutdown + for conn in self.connections: + conn.send_error("server shutting down") + + @defer.inlineCallbacks + def notifier_listener(self): + """Sits forever looping on the notifier waiting for new data. + """ + while True: + yield self.notifier.wait_once_for_replication() + logger.debug("Woken up by notifier") + # We need to call this each time we get woken up, as per docstring + preserve_fn(self.on_notifier_poke)() + + @defer.inlineCallbacks + def on_notifier_poke(self): + """Checks if there is actually any new data and sends it to the + connections if there are. + + This should get called each time new data is available, even if it + is currently being executed, so that nothing gets missed + """ + if not self.connections: + # Don't bother if nothing is listening + return + + # If we're in the process of checking for new updates, mark that fact + # and return + if self.is_looping: + logger.debug("Noitifier poke loop already running") + self.pending_updates = True + return + + self.pending_updates = True + self.is_looping = True + + try: + # Keep looping while there have been pokes about potential updates. + # This protects against the race where a stream we already checked + # gets an update while we're handling other streams. + while self.pending_updates: + self.pending_updates = False + + with Measure(self.clock, "repl.stream.get_updates"): + # First we tell the streams that they should update their + # current tokens. + for stream in self.streams: + stream.advance_current_token() + + for stream in self.streams: + if stream.last_token == stream.upto_token: + continue + + logger.debug( + "Getting stream: %s: %s -> %s", + stream.NAME, stream.last_token, stream.upto_token + ) + updates, current_token = yield stream.get_updates() + + logger.debug( + "Sending %d updates to %d connections", + len(updates), len(self.connections), + ) + + if updates: + logger.info( + "Streaming: %s -> %s", stream.NAME, updates[-1][0] + ) + stream_updates_counter.inc_by(len(updates), stream.NAME) + + # Some streams return multiple rows with the same stream IDs, + # we need to make sure they get sent out in batches. We do + # this by setting the current token to all but the last of + # a series of updates with the same token to have a None + # token. See RdataCommand for more details. + batched_updates = _batch_updates(updates) + + for conn in self.connections: + for token, row in batched_updates: + try: + conn.stream_update(stream.NAME, token, row) + except Exception: + logger.exception("Failed to replicate") + + logger.debug("No more pending updates, breaking poke loop") + finally: + self.pending_updates = False + self.is_looping = False + + @measure_func("repl.get_stream_updates") + def get_stream_updates(self, stream_name, token): + """For a given stream get all updates since token. This is called when + a client first subscribes to a stream. + """ + stream = self.streams_by_name.get(stream_name, None) + if not stream: + raise Exception("unknown stream %s", stream_name) + + return stream.get_updates_since(token) + + @measure_func("repl.federation_ack") + def federation_ack(self, token): + """We've received an ack for federation stream from a client. + """ + federation_ack_counter.inc() + if self.federation_sender: + self.federation_sender.federation_ack(token) + + @measure_func("repl.on_user_sync") + def on_user_sync(self, conn_id, user_id, is_syncing): + """A client has started/stopped syncing on a worker. + """ + user_sync_counter.inc() + self.presence_handler.update_external_syncs_row( + conn_id, user_id, is_syncing + ) + + @measure_func("repl.on_remove_pusher") + @defer.inlineCallbacks + def on_remove_pusher(self, app_id, push_key, user_id): + """A client has asked us to remove a pusher + """ + remove_pusher_counter.inc() + yield self.store.delete_pusher_by_app_id_pushkey_user_id( + app_id=app_id, pushkey=push_key, user_id=user_id + ) + + self.notifier.on_new_replication_data() + + @measure_func("repl.on_invalidate_cache") + def on_invalidate_cache(self, cache_func, keys): + """The client has asked us to invalidate a cache + """ + invalidate_cache_counter.inc() + getattr(self.store, cache_func).invalidate(tuple(keys)) + + def send_sync_to_all_connections(self, data): + """Sends a SYNC command to all clients. + + Used in tests. + """ + for conn in self.connections: + conn.send_sync(data) + + def new_connection(self, connection): + """A new client connection has been established + """ + self.connections.append(connection) + + def lost_connection(self, connection): + """A client connection has been lost + """ + try: + self.connections.remove(connection) + except ValueError: + pass + + # We need to tell the presence handler that the connection has been + # lost so that it can handle any ongoing syncs on that connection. + self.presence_handler.update_external_syncs_clear(connection.conn_id) + + +def _batch_updates(updates): + """Takes a list of updates of form [(token, row)] and sets the token to + None for all rows where the next row has the same token. This is used to + implement batching. + + For example: + + [(1, _), (1, _), (2, _), (3, _), (3, _)] + + becomes: + + [(None, _), (1, _), (2, _), (None, _), (3, _)] + """ + if not updates: + return [] + + new_updates = [] + for i, update in enumerate(updates[:-1]): + if update[0] == updates[i + 1][0]: + new_updates.append((None, update[1])) + else: + new_updates.append(update) + + new_updates.append(updates[-1]) + return new_updates |