kaslo/synapse
1
0
Fork 0
Code Wiki Activity

Remove the TCP protocol implementation.

Browse Source
This commit is contained in:
Patrick Cloke
2022-02-11 12:54:05 -05:00
parent 93ee0bc2b3
commit b4d5b0d697
2 changed files with 3 additions and 550 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
synapse/replication/tcp/__init__.py
View File

@@ -41,7 +41,7 @@ The general interaction of the classes are:
v |
+-------------+
| Protocols |
| (TCP/redis) |
| (Redis) |
+-------------+
Where the ReplicationDataHandler (or subclasses) handles incoming stream

551
synapse/replication/tcp/protocol.py
View File

@@ -11,82 +11,10 @@
# 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
> POSITION events 1
> POSITION backfill 1
> POSITION caches 1
> RDATA caches 2 ["get_user_by_id",["@01register-user:localhost:8823"],1490197670513]
> RDATA events 14 ["ev", ["$149019767112vOHxz:localhost:8823",
"!AFDCvgApUmpdfVjIXm:localhost:8823","m.room.guest_access","",null]]
< PING 1490197675618
> ERROR server stopping
* connection closed by server *
"""
import fcntl
import logging
import struct
from inspect import isawaitable
from typing import TYPE_CHECKING, Any, Collection, List, Optional
from prometheus_client import Counter
from zope.interface import Interface, implementer
from zope.interface import Interface
from twisted.internet import task
from twisted.internet.tcp import Connection
from twisted.protocols.basic import LineOnlyReceiver
from twisted.python.failure import Failure
from synapse.logging.context import PreserveLoggingContext
from synapse.metrics import LaterGauge
from synapse.metrics.background_process_metrics import (
BackgroundProcessLoggingContext,
run_as_background_process,
)
from synapse.replication.tcp.commands import (
VALID_CLIENT_COMMANDS,
VALID_SERVER_COMMANDS,
Command,
ErrorCommand,
NameCommand,
PingCommand,
ReplicateCommand,
ServerCommand,
parse_command_from_line,
)
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"]
)
from synapse.replication.tcp.commands import Command
tcp_inbound_commands_counter = Counter(
"synapse_replication_tcp_protocol_inbound_commands",
@@ -100,484 +28,9 @@ tcp_outbound_commands_counter = Counter(
["command", "name"],
)
# A list of all connected protocols. This allows us to send metrics about the
# connections.
connected_connections: "List[BaseReplicationStreamProtocol]" = []
logger = logging.getLogger(__name__)
PING_TIME = 5000
PING_TIMEOUT_MULTIPLIER = 5
PING_TIMEOUT_MS = PING_TIME * PING_TIMEOUT_MULTIPLIER
class ConnectionStates:
CONNECTING = "connecting"
ESTABLISHED = "established"
PAUSED = "paused"
CLOSED = "closed"
class IReplicationConnection(Interface):
"""An interface for replication connections."""
def send_command(cmd: Command) -> None:
"""Send the command down the connection"""
@implementer(IReplicationConnection)
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 before delegating to `ReplicationCommandHandler.on_<COMMAND_NAME>`.
`ReplicationCommandHandler.on_<COMMAND_NAME>` can optionally return a coroutine;
if so, that will get run as a background process.
It also sends `PING` periodically, and correctly times out remote connections
(if they send a `PING` command)
"""
# The transport is going to be an ITCPTransport, but that doesn't have the
# (un)registerProducer methods, those are only on the implementation.
transport: Connection
delimiter = b"\n"
# Valid commands we expect to receive
VALID_INBOUND_COMMANDS: Collection[str] = []
# Valid commands we can send
VALID_OUTBOUND_COMMANDS: Collection[str] = []
max_line_buffer = 10000
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
# When we requested the connection be closed
self.time_we_closed: Optional[int] = None
self.received_ping = False # Have we received 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: List[Command] = []
# The LoopingCall for sending pings.
self._send_ping_loop: Optional[task.LoopingCall] = None
# a logcontext which we use for processing incoming commands. We declare it as a
# background process so that the CPU stats get reported to prometheus.
with PreserveLoggingContext():
# thanks to `PreserveLoggingContext()`, the new logcontext is guaranteed to
# capture the sentinel context as its containing context and won't prevent
# GC of / unintentionally reactivate what would be the current context.
self._logging_context = BackgroundProcessLoggingContext(
"replication-conn", self.conn_id
)
def connectionMade(self) -> None:
logger.info("[%s] Connection established", self.id())
self.state = ConnectionStates.ESTABLISHED
connected_connections.append(self) # Register connection for metrics
assert self.transport is not None
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(str(self.clock.time_msec())))
self.command_handler.new_connection(self)
def send_ping(self) -> None:
"""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()
)
assert self.transport is not None
self.transport.abortConnection()
else:
if now - self.last_sent_command >= PING_TIME:
self.send_command(PingCommand(str(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: bytes) -> None:
"""Called when we've received a line"""
with PreserveLoggingContext(self._logging_context):
self._parse_and_dispatch_line(line)
def _parse_and_dispatch_line(self, line: bytes) -> None:
if line.strip() == b"":
# Ignore blank lines
return
linestr = line.decode("utf-8")
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
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()
tcp_inbound_commands_counter.labels(cmd.NAME, self.name).inc()
self.handle_command(cmd)
def handle_command(self, cmd: Command) -> None:
"""Handle a command we have received over the replication stream.
First calls `self.on_<COMMAND>` if it exists, then calls
`self.command_handler.on_<COMMAND>` if it exists (which can optionally
return an Awaitable).
This allows for protocol level handling of commands (e.g. PINGs), before
delegating to the handler.
Args:
cmd: received command
"""
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:
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:
res = cmd_func(self, cmd)
# the handler might be a coroutine: fire it off as a background process
# if so.
if isawaitable(res):
run_as_background_process(
"replication-" + cmd.get_logcontext_id(), lambda: res
)
handled = True
if not handled:
logger.warning("Unhandled command: %r", cmd)
def close(self) -> None:
logger.warning("[%s] Closing connection", self.id())
self.time_we_closed = self.clock.time_msec()
assert self.transport is not None
self.transport.loseConnection()
self.on_connection_closed()
def send_error(self, error_string: str, *args: Any) -> None:
"""Send an error to remote and close the connection."""
self.send_command(ErrorCommand(error_string % args))
self.close()
def send_command(self, cmd: Command, do_buffer: bool = True) -> None:
"""Send a command if connection has been established.
Args:
cmd
do_buffer: 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
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)
encoded_string = string.encode("utf-8")
if len(encoded_string) > self.MAX_LENGTH:
raise Exception(
"Failed to send command %s as too long (%d > %d)"
% (cmd.NAME, len(encoded_string), self.MAX_LENGTH)
)
self.sendLine(encoded_string)
self.last_sent_command = self.clock.time_msec()
def _queue_command(self, cmd: Command) -> None:
"""Queue the command until the connection is ready to write to again."""
logger.debug("[%s] Queueing 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) -> None:
"""Send any queued commandes"""
pending = self.pending_commands
self.pending_commands = []
for cmd in pending:
self.send_command(cmd)
def on_PING(self, cmd: PingCommand) -> None:
self.received_ping = True
def on_ERROR(self, cmd: ErrorCommand) -> None:
logger.error("[%s] Remote reported error: %r", self.id(), cmd.data)
def pauseProducing(self) -> None:
"""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) -> None:
"""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) -> None:
"""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: Failure) -> None: # type: ignore[override]
logger.info("[%s] Replication connection closed: %r", self.id(), reason)
if isinstance(reason, Failure):
assert reason.type is not None
connection_close_counter.labels(reason.type.__name__).inc()
else:
connection_close_counter.labels(reason.__class__.__name__).inc() # type: ignore[unreachable]
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) -> None:
logger.info("[%s] Connection was closed", self.id())
self.state = ConnectionStates.CLOSED
self.pending_commands = []
self.command_handler.lost_connection(self)
if self.transport:
self.transport.unregisterProducer()
# mark the logging context as finished by triggering `__exit__()`
with PreserveLoggingContext():
with self._logging_context:
pass
# the sentinel context is now active, which may not be correct.
# PreserveLoggingContext() will restore the correct logging context.
def __str__(self) -> str:
addr = None
if self.transport:
addr = str(self.transport.getPeer())
return "ReplicationConnection<name=%s,conn_id=%s,addr=%s>" % (
self.name,
self.conn_id,
addr,
)
def id(self) -> str:
return "%s-%s" % (self.name, self.conn_id)
def lineLengthExceeded(self, line: str) -> None:
"""Called when we receive a line that is above the maximum line length"""
self.send_error("Line length exceeded")
class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
VALID_INBOUND_COMMANDS = VALID_CLIENT_COMMANDS
VALID_OUTBOUND_COMMANDS = VALID_SERVER_COMMANDS
def __init__(
self, server_name: str, clock: Clock, handler: "ReplicationCommandHandler"
):
super().__init__(clock, handler)
self.server_name = server_name
def connectionMade(self) -> None:
self.send_command(ServerCommand(self.server_name))
super().connectionMade()
def on_NAME(self, cmd: NameCommand) -> None:
logger.info("[%s] Renamed to %r", self.id(), cmd.data)
self.name = cmd.data
class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS
VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS
def __init__(
self,
hs: "HomeServer",
client_name: str,
server_name: str,
clock: Clock,
command_handler: "ReplicationCommandHandler",
):
super().__init__(clock, command_handler)
self.client_name = client_name
self.server_name = server_name
def connectionMade(self) -> None:
self.send_command(NameCommand(self.client_name))
super().connectionMade()
# Once we've connected subscribe to the necessary streams
self.replicate()
def on_SERVER(self, cmd: ServerCommand) -> None:
if cmd.data != self.server_name:
logger.error("[%s] Connected to wrong remote: %r", self.id(), cmd.data)
self.send_error("Wrong remote")
def replicate(self) -> None:
"""Send the subscription request to the server"""
logger.info("[%s] Subscribing to replication streams", self.id())
self.send_command(ReplicateCommand())
# The following simply registers metrics for the replication connections
pending_commands = LaterGauge(
"synapse_replication_tcp_protocol_pending_commands",
"",
["name"],
lambda: {(p.name,): len(p.pending_commands) for p in connected_connections},
)
def transport_buffer_size(protocol: BaseReplicationStreamProtocol) -> int:
if protocol.transport:
size = len(protocol.transport.dataBuffer) + protocol.transport._tempDataLen
return size
return 0
transport_send_buffer = LaterGauge(
"synapse_replication_tcp_protocol_transport_send_buffer",
"",
["name"],
lambda: {(p.name,): transport_buffer_size(p) for p in connected_connections},
)
def transport_kernel_read_buffer_size(
protocol: BaseReplicationStreamProtocol, read: bool = True
) -> int:
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, b"\0\0\0\0"))[0]
return size
return 0
tcp_transport_kernel_send_buffer = LaterGauge(
"synapse_replication_tcp_protocol_transport_kernel_send_buffer",
"",
["name"],
lambda: {
(p.name,): transport_kernel_read_buffer_size(p, False)
for p in connected_connections
},
)
tcp_transport_kernel_read_buffer = LaterGauge(
"synapse_replication_tcp_protocol_transport_kernel_read_buffer",
"",
["name"],
lambda: {
(p.name,): transport_kernel_read_buffer_size(p, True)
for p in connected_connections
},
)