Move client command handling out of TCP protocol (#7185)

The aim here is to move the command handling out of the TCP protocol classes and to also merge the client and server command handling (so that we can reuse them for redis protocol). This PR simply moves the client paths to the new `ReplicationCommandHandler`, a future PR will move the server paths too.
This commit is contained in:
Erik Johnston 2020-04-06 09:58:42 +01:00 committed by GitHub
parent d73bf18d13
commit 5016b162fc
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12 changed files with 379 additions and 372 deletions

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@ -46,12 +46,11 @@ indicate which side is sending, these are *not* included on the wire::
> ERROR server stopping
* connection closed by server *
"""
import abc
import fcntl
import logging
import struct
from collections import defaultdict
from typing import Any, DefaultDict, Dict, List, Set
from typing import TYPE_CHECKING, DefaultDict, List
from six import iteritems
@ -78,13 +77,12 @@ from synapse.replication.tcp.commands import (
SyncCommand,
UserSyncCommand,
)
from synapse.replication.tcp.streams import STREAMS_MAP, Stream
from synapse.types import Collection
from synapse.util import Clock
from synapse.util.stringutils import random_string
MYPY = False
if MYPY:
if TYPE_CHECKING:
from synapse.replication.tcp.handler import ReplicationCommandHandler
from synapse.server import HomeServer
@ -475,71 +473,6 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
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
VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS
@ -550,7 +483,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
client_name: str,
server_name: str,
clock: Clock,
handler: AbstractReplicationClientHandler,
command_handler: "ReplicationCommandHandler",
):
BaseReplicationStreamProtocol.__init__(self, clock)
@ -558,20 +491,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
self.client_name = client_name
self.server_name = server_name
self.handler = handler
self.streams = {
stream.NAME: stream(hs) for stream in STREAMS_MAP.values()
} # type: Dict[str, Stream]
# 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(STREAMS_MAP) # type: Set[str]
# Map of stream to batched updates. See RdataCommand for info on how
# batching works.
self.pending_batches = {} # type: Dict[str, List[Any]]
self.handler = command_handler
def connectionMade(self):
self.send_command(NameCommand(self.client_name))
@ -589,90 +509,40 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
# We've now finished connecting to so inform the client handler
self.handler.update_connection(self)
self.handler.finished_connecting()
async def handle_command(self, cmd: Command):
"""Handle a command we have received over the replication stream.
Delegates to `command_handler.on_<COMMAND>`, which must return an
awaitable.
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:
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)
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 or stream_name in self.streams_connecting:
# 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: PositionCommand):
stream = self.streams.get(cmd.stream_name)
if not stream:
logger.error("Got POSITION for unknown stream: %s", cmd.stream_name)
return
# Find where we previously streamed up to.
current_token = self.handler.get_streams_to_replicate().get(cmd.stream_name)
if current_token is None:
logger.warning(
"Got POSITION for stream we're not subscribed to: %s", cmd.stream_name
)
return
# Fetch all updates between then and now.
limited = True
while limited:
updates, current_token, limited = await stream.get_updates_since(
current_token, cmd.token
)
# Check if the connection was closed underneath us, if so we bail
# rather than risk having concurrent catch ups going on.
if self.state == ConnectionStates.CLOSED:
return
if updates:
await self.handler.on_rdata(
cmd.stream_name,
current_token,
[stream.parse_row(update[1]) for update in updates],
)
# We've now caught up to position sent to us, notify handler.
await self.handler.on_position(cmd.stream_name, cmd.token)
self.streams_connecting.discard(cmd.stream_name)
if not self.streams_connecting:
self.handler.finished_connecting()
# Check if the connection was closed underneath us, if so we bail
# rather than risk having concurrent catch ups going on.
if self.state == ConnectionStates.CLOSED:
return
# Handle any RDATA that came in while we were catching up.
rows = self.pending_batches.pop(cmd.stream_name, [])
if rows:
await self.handler.on_rdata(cmd.stream_name, rows[-1].token, rows)
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)
def replicate(self):
"""Send the subscription request to the server
"""
@ -768,8 +638,3 @@ tcp_outbound_commands = LaterGauge(
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"]
)