# -*- 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. """This module contains the implementation of both the client and server protocols. The basic structure of the protocol is line based, where the initial word of each line specifies the command. The rest of the line is parsed based on the command. For example, the `RDATA` command is defined as:: RDATA <stream_name> <token> <row_json> (Note that `<row_json>` may contains spaces, but cannot contain newlines.) Blank lines are ignored. # Example An example iteraction is shown below. Each line is prefixed with '>' or '<' to indicate which side is sending, these are *not* included on the wire:: * connection established * > SERVER localhost:8823 > PING 1490197665618 < NAME synapse.app.appservice < PING 1490197665618 < REPLICATE events 1 < REPLICATE backfill 1 < REPLICATE caches 1 > POSITION events 1 > POSITION backfill 1 > POSITION caches 1 > RDATA caches 2 ["get_user_by_id",["@01register-user:localhost:8823"],1490197670513] > RDATA events 14 ["$149019767112vOHxz:localhost:8823", "!AFDCvgApUmpdfVjIXm:localhost:8823","m.room.guest_access","",null] < PING 1490197675618 > ERROR server stopping * connection closed by server * """ from twisted.internet import defer from twisted.protocols.basic import LineOnlyReceiver from twisted.python.failure import Failure from .commands import ( COMMAND_MAP, VALID_CLIENT_COMMANDS, VALID_SERVER_COMMANDS, ErrorCommand, ServerCommand, RdataCommand, PositionCommand, PingCommand, NameCommand, ReplicateCommand, UserSyncCommand, SyncCommand, ) from .streams import STREAMS_MAP from synapse.util.stringutils import random_string from synapse.metrics.metric import CounterMetric import logging import synapse.metrics import struct import fcntl metrics = synapse.metrics.get_metrics_for(__name__) connection_close_counter = metrics.register_counter( "close_reason", labels=["reason_type"], ) # A list of all connected protocols. This allows us to send metrics about the # connections. connected_connections = [] logger = logging.getLogger(__name__) PING_TIME = 5000 PING_TIMEOUT_MULTIPLIER = 5 PING_TIMEOUT_MS = PING_TIME * PING_TIMEOUT_MULTIPLIER class ConnectionStates(object): CONNECTING = "connecting" ESTABLISHED = "established" PAUSED = "paused" CLOSED = "closed" class BaseReplicationStreamProtocol(LineOnlyReceiver): """Base replication protocol shared between client and server. Reads lines (ignoring blank ones) and parses them into command classes, asserting that they are valid for the given direction, i.e. server commands are only sent by the server. On receiving a new command it calls `on_<COMMAND_NAME>` with the parsed command. It also sends `PING` periodically, and correctly times out remote connections (if they send a `PING` command) """ delimiter = b'\n' VALID_INBOUND_COMMANDS = [] # Valid commands we expect to receive VALID_OUTBOUND_COMMANDS = [] # Valid commans we can send max_line_buffer = 10000 def __init__(self, clock): self.clock = clock self.last_received_command = self.clock.time_msec() self.last_sent_command = 0 self.time_we_closed = None # When we requested the connection be closed self.received_ping = False # Have we reecived a ping from the other side self.state = ConnectionStates.CONNECTING self.name = "anon" # The name sent by a client. self.conn_id = random_string(5) # To dedupe in case of name clashes. # List of pending commands to send once we've established the connection self.pending_commands = [] # The LoopingCall for sending pings. self._send_ping_loop = None self.inbound_commands_counter = CounterMetric( "inbound_commands", labels=["command"], ) self.outbound_commands_counter = CounterMetric( "outbound_commands", labels=["command"], ) def connectionMade(self): logger.info("[%s] Connection established", self.id()) self.state = ConnectionStates.ESTABLISHED connected_connections.append(self) # Register connection for metrics self.transport.registerProducer(self, True) # For the *Producing callbacks self._send_pending_commands() # Starts sending pings self._send_ping_loop = self.clock.looping_call(self.send_ping, 5000) # Always send the initial PING so that the other side knows that they # can time us out. self.send_command(PingCommand(self.clock.time_msec())) def send_ping(self): """Periodically sends a ping and checks if we should close the connection due to the other side timing out. """ now = self.clock.time_msec() if self.time_we_closed: if now - self.time_we_closed > PING_TIMEOUT_MS: logger.info( "[%s] Failed to close connection gracefully, aborting", self.id() ) self.transport.abortConnection() else: if now - self.last_sent_command >= PING_TIME: self.send_command(PingCommand(now)) if self.received_ping and now - self.last_received_command > PING_TIMEOUT_MS: logger.info( "[%s] Connection hasn't received command in %r ms. Closing.", self.id(), now - self.last_received_command ) self.send_error("ping timeout") def lineReceived(self, line): """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) 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.last_received_command = self.clock.time_msec() self.inbound_commands_counter.inc(cmd_name) 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 try: getattr(self, "on_%s" % (cmd_name,))(cmd) except Exception: logger.exception("[%s] Failed to handle line: %r", self.id(), line) def close(self): logger.warn("[%s] Closing connection", self.id()) self.time_we_closed = self.clock.time_msec() self.transport.loseConnection() self.on_connection_closed() def send_error(self, error_string, *args): """Send an error to remote and close the connection. """ self.send_command(ErrorCommand(error_string % args)) self.close() def send_command(self, cmd, do_buffer=True): """Send a command if connection has been established. Args: cmd (Command) do_buffer (bool): Whether to buffer the message or always attempt to send the command. This is mostly used to send an error message if we're about to close the connection due our buffers becoming full. """ if self.state == ConnectionStates.CLOSED: logger.debug("[%s] Not sending, connection closed", self.id()) return if do_buffer and self.state != ConnectionStates.ESTABLISHED: self._queue_command(cmd) return self.outbound_commands_counter.inc(cmd.NAME) string = "%s %s" % (cmd.NAME, cmd.to_line(),) if "\n" in string: raise Exception("Unexpected newline in command: %r", string) self.sendLine(string.encode("utf-8")) self.last_sent_command = self.clock.time_msec() def _queue_command(self, cmd): """Queue the command until the connection is ready to write to again. """ logger.debug("[%s] Queing as conn %r, cmd: %r", self.id(), self.state, cmd) self.pending_commands.append(cmd) if len(self.pending_commands) > self.max_line_buffer: # The other side is failing to keep up and out buffers are becoming # full, so lets close the connection. # XXX: should we squawk more loudly? logger.error("[%s] Remote failed to keep up", self.id()) self.send_command(ErrorCommand("Failed to keep up"), do_buffer=False) self.close() def _send_pending_commands(self): """Send any queued commandes """ pending = self.pending_commands self.pending_commands = [] for cmd in pending: self.send_command(cmd) def on_PING(self, line): self.received_ping = True def on_ERROR(self, cmd): logger.error("[%s] Remote reported error: %r", self.id(), cmd.data) def pauseProducing(self): """This is called when both the kernel send buffer and the twisted tcp connection send buffers have become full. We don't actually have any control over those sizes, so we buffer some commands ourselves before knifing the connection due to the remote failing to keep up. """ logger.info("[%s] Pause producing", self.id()) self.state = ConnectionStates.PAUSED def resumeProducing(self): """The remote has caught up after we started buffering! """ logger.info("[%s] Resume producing", self.id()) self.state = ConnectionStates.ESTABLISHED self._send_pending_commands() def stopProducing(self): """We're never going to send any more data (normally because either we or the remote has closed the connection) """ logger.info("[%s] Stop producing", self.id()) self.on_connection_closed() def connectionLost(self, reason): logger.info("[%s] Replication connection closed: %r", self.id(), reason) if isinstance(reason, Failure): connection_close_counter.inc(reason.type.__name__) else: connection_close_counter.inc(reason.__class__.__name__) try: # Remove us from list of connections to be monitored connected_connections.remove(self) except ValueError: pass # Stop the looping call sending pings. if self._send_ping_loop and self._send_ping_loop.running: self._send_ping_loop.stop() self.on_connection_closed() def on_connection_closed(self): logger.info("[%s] Connection was closed", self.id()) self.state = ConnectionStates.CLOSED self.pending_commands = [] if self.transport: self.transport.unregisterProducer() def __str__(self): return "ReplicationConnection<name=%s,conn_id=%s,addr=%s>" % ( self.name, self.conn_id, self.addr, ) def id(self): return "%s-%s" % (self.name, self.conn_id) class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol): VALID_INBOUND_COMMANDS = VALID_CLIENT_COMMANDS VALID_OUTBOUND_COMMANDS = VALID_SERVER_COMMANDS def __init__(self, server_name, clock, streamer, addr): BaseReplicationStreamProtocol.__init__(self, clock) # Old style class self.server_name = server_name self.streamer = streamer self.addr = addr # The streams the client has subscribed to and is up to date with self.replication_streams = set() # The streams the client is currently subscribing to. self.connecting_streams = set() # Map from stream name to list of updates to send once we've finished # subscribing the client to the stream. self.pending_rdata = {} def connectionMade(self): self.send_command(ServerCommand(self.server_name)) BaseReplicationStreamProtocol.connectionMade(self) self.streamer.new_connection(self) def on_NAME(self, cmd): logger.info("[%s] Renamed to %r", self.id(), cmd.data) self.name = cmd.data def on_USER_SYNC(self, cmd): self.streamer.on_user_sync( self.conn_id, cmd.user_id, cmd.is_syncing, cmd.last_sync_ms, ) 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. for stream in self.streamer.streams_by_name.iterkeys(): self.subscribe_to_stream(stream, token) else: self.subscribe_to_stream(stream_name, token) def on_FEDERATION_ACK(self, cmd): self.streamer.federation_ack(cmd.token) def on_REMOVE_PUSHER(self, cmd): self.streamer.on_remove_pusher(cmd.app_id, cmd.push_key, cmd.user_id) def on_INVALIDATE_CACHE(self, cmd): self.streamer.on_invalidate_cache(cmd.cache_func, cmd.keys) 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, ) @defer.inlineCallbacks def subscribe_to_stream(self, stream_name, token): """Subscribe the remote to a streams. 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 = yield 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, []) for token, update in pending_rdata: # Only send updates newer than the current token if token > current_token: self.send_command(RdataCommand(stream_name, token, update)) # 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 on_connection_closed(self): BaseReplicationStreamProtocol.on_connection_closed(self) self.streamer.lost_connection(self) class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol): VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS def __init__(self, client_name, server_name, clock, handler): BaseReplicationStreamProtocol.__init__(self, clock) self.client_name = client_name self.server_name = server_name self.handler = handler # Map of stream to batched updates. See RdataCommand for info on how # batching works. self.pending_batches = {} def connectionMade(self): self.send_command(NameCommand(self.client_name)) BaseReplicationStreamProtocol.connectionMade(self) # Once we've connected subscribe to the necessary streams for stream_name, token in self.handler.get_streams_to_replicate().iteritems(): 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) 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") def on_RDATA(self, cmd): stream_name = cmd.stream_name inbound_rdata_count.inc(stream_name) try: row = STREAMS_MAP[stream_name].ROW_TYPE(*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) self.handler.on_rdata(stream_name, cmd.token, rows) def on_POSITION(self, cmd): self.handler.on_position(cmd.stream_name, cmd.token) def on_SYNC(self, cmd): self.handler.on_sync(cmd.data) def replicate(self, stream_name, token): """Send the subscription request to the server """ 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.send_command(ReplicateCommand(stream_name, token)) def on_connection_closed(self): BaseReplicationStreamProtocol.on_connection_closed(self) self.handler.update_connection(None) # The following simply registers metrics for the replication connections metrics.register_callback( "pending_commands", lambda: { (p.name, p.conn_id): len(p.pending_commands) for p in connected_connections }, labels=["name", "conn_id"], ) def transport_buffer_size(protocol): if protocol.transport: size = len(protocol.transport.dataBuffer) + protocol.transport._tempDataLen return size return 0 metrics.register_callback( "transport_send_buffer", lambda: { (p.name, p.conn_id): transport_buffer_size(p) for p in connected_connections }, labels=["name", "conn_id"], ) def transport_kernel_read_buffer_size(protocol, read=True): SIOCINQ = 0x541B SIOCOUTQ = 0x5411 if protocol.transport: fileno = protocol.transport.getHandle().fileno() if read: op = SIOCINQ else: op = SIOCOUTQ size = struct.unpack("I", fcntl.ioctl(fileno, op, '\0\0\0\0'))[0] return size return 0 metrics.register_callback( "transport_kernel_send_buffer", lambda: { (p.name, p.conn_id): transport_kernel_read_buffer_size(p, False) for p in connected_connections }, labels=["name", "conn_id"], ) metrics.register_callback( "transport_kernel_read_buffer", lambda: { (p.name, p.conn_id): transport_kernel_read_buffer_size(p, True) for p in connected_connections }, labels=["name", "conn_id"], ) metrics.register_callback( "inbound_commands", lambda: { (k[0], p.name, p.conn_id): count for p in connected_connections for k, count in p.inbound_commands_counter.counts.iteritems() }, labels=["command", "name", "conn_id"], ) metrics.register_callback( "outbound_commands", lambda: { (k[0], p.name, p.conn_id): count for p in connected_connections for k, count in p.outbound_commands_counter.counts.iteritems() }, labels=["command", "name", "conn_id"], ) # number of updates received for each RDATA stream inbound_rdata_count = metrics.register_counter( "inbound_rdata_count", labels=["stream_name"], )