forked-synapse/synapse/federation/sender/__init__.py

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# Copyright 2019 New Vector 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 Federation Sender is responsible for sending Persistent Data Units (PDUs)
and Ephemeral Data Units (EDUs) to other homeservers using
the `/send` Federation API.
## How do PDUs get sent?
The Federation Sender is made aware of new PDUs due to `FederationSender.notify_new_events`.
When the sender is notified about a newly-persisted PDU that originates from this homeserver
and is not an out-of-band event, we pass the PDU to the `_PerDestinationQueue` for each
remote homeserver that is in the room at that point in the DAG.
### Per-Destination Queues
There is one `PerDestinationQueue` per 'destination' homeserver.
The `PerDestinationQueue` maintains the following information about the destination:
- whether the destination is currently in [catch-up mode (see below)](#catch-up-mode);
- a queue of PDUs to be sent to the destination; and
- a queue of EDUs to be sent to the destination (not considered in this section).
Upon a new PDU being enqueued, `attempt_new_transaction` is called to start a new
transaction if there is not already one in progress.
### Transactions and the Transaction Transmission Loop
Each federation HTTP request to the `/send` endpoint is referred to as a 'transaction'.
The body of the HTTP request contains a list of PDUs and EDUs to send to the destination.
The *Transaction Transmission Loop* (`_transaction_transmission_loop`) is responsible
for emptying the queued PDUs (and EDUs) from a `PerDestinationQueue` by sending
them to the destination.
There can only be one transaction in flight for a given destination at any time.
(Other than preventing us from overloading the destination, this also makes it easier to
reason about because we process events sequentially for each destination.
This is useful for *Catch-Up Mode*, described later.)
The loop continues so long as there is anything to send. At each iteration of the loop, we:
- dequeue up to 50 PDUs (and up to 100 EDUs).
- make the `/send` request to the destination homeserver with the dequeued PDUs and EDUs.
- if successful, make note of the fact that we succeeded in transmitting PDUs up to
the given `stream_ordering` of the latest PDU by
- if unsuccessful, back off from the remote homeserver for some time.
If we have been unsuccessful for too long (when the backoff interval grows to exceed 1 hour),
the in-memory queues are emptied and we enter [*Catch-Up Mode*, described below](#catch-up-mode).
### Catch-Up Mode
When the `PerDestinationQueue` has the catch-up flag set, the *Catch-Up Transmission Loop*
(`_catch_up_transmission_loop`) is used in lieu of the regular `_transaction_transmission_loop`.
(Only once the catch-up mode has been exited can the regular tranaction transmission behaviour
be resumed.)
*Catch-Up Mode*, entered upon Synapse startup or once a homeserver has fallen behind due to
connection problems, is responsible for sending PDUs that have been missed by the destination
homeserver. (PDUs can be missed because the `PerDestinationQueue` is volatile i.e. resets
on startup and it does not hold PDUs forever if `/send` requests to the destination fail.)
The catch-up mechanism makes use of the `last_successful_stream_ordering` column in the
`destinations` table (which gives the `stream_ordering` of the most recent successfully
sent PDU) and the `stream_ordering` column in the `destination_rooms` table (which gives,
for each room, the `stream_ordering` of the most recent PDU that needs to be sent to this
destination).
Each iteration of the loop pulls out 50 `destination_rooms` entries with the oldest
`stream_ordering`s that are greater than the `last_successful_stream_ordering`.
In other words, from the set of latest PDUs in each room to be sent to the destination,
the 50 oldest such PDUs are pulled out.
These PDUs could, in principle, now be directly sent to the destination. However, as an
optimisation intended to prevent overloading destination homeservers, we instead attempt
to send the latest forward extremities so long as the destination homeserver is still
eligible to receive those.
This reduces load on the destination **in aggregate** because all Synapse homeservers
will behave according to this principle and therefore avoid sending lots of different PDUs
at different points in the DAG to a recovering homeserver.
*This optimisation is not currently valid in rooms which are partial-state on this homeserver,
since we are unable to determine whether the destination homeserver is eligible to receive
the latest forward extremities unless this homeserver sent those PDUs in this case, we
just send the latest PDUs originating from this server and skip this optimisation.*
Whilst PDUs are sent through this mechanism, the position of `last_successful_stream_ordering`
is advanced as normal.
Once there are no longer any rooms containing outstanding PDUs to be sent to the destination
*that are not already in the `PerDestinationQueue` because they arrived since Catch-Up Mode
was enabled*, Catch-Up Mode is exited and we return to `_transaction_transmission_loop`.
#### A note on failures and back-offs
If a remote server is unreachable over federation, we back off from that server,
with an exponentially-increasing retry interval.
Whilst we don't automatically retry after the interval, we prevent making new attempts
until such time as the back-off has cleared.
Once the back-off is cleared and a new PDU or EDU arrives for transmission, the transmission
loop resumes and empties the queue by making federation requests.
If the backoff grows too large (> 1 hour), the in-memory queue is emptied (to prevent
unbounded growth) and Catch-Up Mode is entered.
It is worth noting that the back-off for a remote server is cleared once an inbound
request from that remote server is received (see `notify_remote_server_up`).
At this point, the transaction transmission loop is also started up, to proactively
send missed PDUs and EDUs to the destination (i.e. you don't need to wait for a new PDU
or EDU, destined for that destination, to be created in order to send out missed PDUs and
EDUs).
"""
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import abc
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import logging
from collections import OrderedDict
from typing import (
TYPE_CHECKING,
Collection,
Dict,
Hashable,
Iterable,
List,
Optional,
Set,
Tuple,
)
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import attr
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from prometheus_client import Counter
from typing_extensions import Literal
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from twisted.internet import defer
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from twisted.internet.interfaces import IDelayedCall
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import synapse.metrics
from synapse.api.presence import UserPresenceState
from synapse.events import EventBase
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from synapse.federation.sender.per_destination_queue import PerDestinationQueue
from synapse.federation.sender.transaction_manager import TransactionManager
from synapse.federation.units import Edu
from synapse.logging.context import make_deferred_yieldable, run_in_background
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from synapse.metrics import (
LaterGauge,
event_processing_loop_counter,
event_processing_loop_room_count,
events_processed_counter,
)
from synapse.metrics.background_process_metrics import (
run_as_background_process,
wrap_as_background_process,
)
from synapse.types import JsonDict, ReadReceipt, RoomStreamToken
from synapse.util import Clock
from synapse.util.metrics import Measure
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if TYPE_CHECKING:
from synapse.events.presence_router import PresenceRouter
from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
sent_pdus_destination_dist_count = Counter(
"synapse_federation_client_sent_pdu_destinations_count",
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"Number of PDUs queued for sending to one or more destinations",
)
sent_pdus_destination_dist_total = Counter(
"synapse_federation_client_sent_pdu_destinations",
"Total number of PDUs queued for sending across all destinations",
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)
# Time (in s) after Synapse's startup that we will begin to wake up destinations
# that have catch-up outstanding.
CATCH_UP_STARTUP_DELAY_SEC = 15
# Time (in s) to wait in between waking up each destination, i.e. one destination
# will be woken up every <x> seconds after Synapse's startup until we have woken
# every destination has outstanding catch-up.
CATCH_UP_STARTUP_INTERVAL_SEC = 5
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class AbstractFederationSender(metaclass=abc.ABCMeta):
@abc.abstractmethod
def notify_new_events(self, max_token: RoomStreamToken) -> None:
"""This gets called when we have some new events we might want to
send out to other servers.
"""
raise NotImplementedError()
@abc.abstractmethod
async def send_read_receipt(self, receipt: ReadReceipt) -> None:
"""Send a RR to any other servers in the room
Args:
receipt: receipt to be sent
"""
raise NotImplementedError()
@abc.abstractmethod
def send_presence_to_destinations(
self, states: Iterable[UserPresenceState], destinations: Iterable[str]
) -> None:
"""Send the given presence states to the given destinations.
Args:
destinations:
"""
raise NotImplementedError()
@abc.abstractmethod
def build_and_send_edu(
self,
destination: str,
edu_type: str,
content: JsonDict,
key: Optional[Hashable] = None,
) -> None:
"""Construct an Edu object, and queue it for sending
Args:
destination: name of server to send to
edu_type: type of EDU to send
content: content of EDU
key: clobbering key for this edu
"""
raise NotImplementedError()
@abc.abstractmethod
def send_device_messages(self, destination: str, immediate: bool = True) -> None:
"""Tells the sender that a new device message is ready to be sent to the
destination. The `immediate` flag specifies whether the messages should
be tried to be sent immediately, or whether it can be delayed for a
short while (to aid performance).
"""
raise NotImplementedError()
@abc.abstractmethod
def wake_destination(self, destination: str) -> None:
"""Called when we want to retry sending transactions to a remote.
This is mainly useful if the remote server has been down and we think it
might have come back.
"""
raise NotImplementedError()
@abc.abstractmethod
def get_current_token(self) -> int:
raise NotImplementedError()
@abc.abstractmethod
def federation_ack(self, instance_name: str, token: int) -> None:
raise NotImplementedError()
@abc.abstractmethod
async def get_replication_rows(
self, instance_name: str, from_token: int, to_token: int, target_row_count: int
) -> Tuple[List[Tuple[int, Tuple]], int, bool]:
raise NotImplementedError()
@attr.s
class _DestinationWakeupQueue:
"""A queue of destinations that need to be woken up due to new updates.
Staggers waking up of per destination queues to ensure that we don't attempt
to start TLS connections with many hosts all at once, leading to pinned CPU.
"""
# The maximum duration in seconds between queuing up a destination and it
# being woken up.
_MAX_TIME_IN_QUEUE = 30.0
# The maximum duration in seconds between waking up consecutive destination
# queues.
_MAX_DELAY = 0.1
sender: "FederationSender" = attr.ib()
clock: Clock = attr.ib()
queue: "OrderedDict[str, Literal[None]]" = attr.ib(factory=OrderedDict)
processing: bool = attr.ib(default=False)
def add_to_queue(self, destination: str) -> None:
"""Add a destination to the queue to be woken up."""
self.queue[destination] = None
if not self.processing:
self._handle()
@wrap_as_background_process("_DestinationWakeupQueue.handle")
async def _handle(self) -> None:
"""Background process to drain the queue."""
if not self.queue:
return
assert not self.processing
self.processing = True
try:
# We start with a delay that should drain the queue quickly enough that
# we process all destinations in the queue in _MAX_TIME_IN_QUEUE
# seconds.
#
# We also add an upper bound to the delay, to gracefully handle the
# case where the queue only has a few entries in it.
current_sleep_seconds = min(
self._MAX_DELAY, self._MAX_TIME_IN_QUEUE / len(self.queue)
)
while self.queue:
destination, _ = self.queue.popitem(last=False)
queue = self.sender._get_per_destination_queue(destination)
if not queue._new_data_to_send:
# The per destination queue has already been woken up.
continue
queue.attempt_new_transaction()
await self.clock.sleep(current_sleep_seconds)
if not self.queue:
break
# More destinations may have been added to the queue, so we may
# need to reduce the delay to ensure everything gets processed
# within _MAX_TIME_IN_QUEUE seconds.
current_sleep_seconds = min(
current_sleep_seconds, self._MAX_TIME_IN_QUEUE / len(self.queue)
)
finally:
self.processing = False
class FederationSender(AbstractFederationSender):
def __init__(self, hs: "HomeServer"):
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self.hs = hs
self.server_name = hs.hostname
self.store = hs.get_datastores().main
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self.state = hs.get_state_handler()
self._storage_controllers = hs.get_storage_controllers()
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self.clock = hs.get_clock()
self.is_mine_id = hs.is_mine_id
self.is_mine_server_name = hs.is_mine_server_name
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self._presence_router: Optional["PresenceRouter"] = None
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self._transaction_manager = TransactionManager(hs)
self._instance_name = hs.get_instance_name()
self._federation_shard_config = hs.config.worker.federation_shard_config
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# map from destination to PerDestinationQueue
self._per_destination_queues: Dict[str, PerDestinationQueue] = {}
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LaterGauge(
"synapse_federation_transaction_queue_pending_destinations",
"",
[],
lambda: sum(
1
for d in self._per_destination_queues.values()
if d.transmission_loop_running
),
)
LaterGauge(
"synapse_federation_transaction_queue_pending_pdus",
"",
[],
lambda: sum(
d.pending_pdu_count() for d in self._per_destination_queues.values()
),
)
LaterGauge(
"synapse_federation_transaction_queue_pending_edus",
"",
[],
lambda: sum(
d.pending_edu_count() for d in self._per_destination_queues.values()
),
)
self._is_processing = False
self._last_poked_id = -1
# map from room_id to a set of PerDestinationQueues which we believe are
# awaiting a call to flush_read_receipts_for_room. The presence of an entry
# here for a given room means that we are rate-limiting RR flushes to that room,
# and that there is a pending call to _flush_rrs_for_room in the system.
self._queues_awaiting_rr_flush_by_room: Dict[str, Set[PerDestinationQueue]] = {}
self._rr_txn_interval_per_room_ms = (
1000.0
/ hs.config.ratelimiting.federation_rr_transactions_per_room_per_second
)
# wake up destinations that have outstanding PDUs to be caught up
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self._catchup_after_startup_timer: Optional[
IDelayedCall
] = self.clock.call_later(
CATCH_UP_STARTUP_DELAY_SEC,
run_as_background_process,
"wake_destinations_needing_catchup",
self._wake_destinations_needing_catchup,
)
self._external_cache = hs.get_external_cache()
self._destination_wakeup_queue = _DestinationWakeupQueue(self, self.clock)
def _get_per_destination_queue(self, destination: str) -> PerDestinationQueue:
"""Get or create a PerDestinationQueue for the given destination
Args:
destination: server_name of remote server
"""
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queue = self._per_destination_queues.get(destination)
if not queue:
queue = PerDestinationQueue(self.hs, self._transaction_manager, destination)
self._per_destination_queues[destination] = queue
return queue
def notify_new_events(self, max_token: RoomStreamToken) -> None:
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"""This gets called when we have some new events we might want to
send out to other servers.
"""
# We just use the minimum stream ordering and ignore the vector clock
# component. This is safe to do as long as we *always* ignore the vector
# clock components.
current_id = max_token.stream
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self._last_poked_id = max(current_id, self._last_poked_id)
if self._is_processing:
return
# fire off a processing loop in the background
run_as_background_process(
"process_event_queue_for_federation", self._process_event_queue_loop
)
async def _process_event_queue_loop(self) -> None:
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try:
self._is_processing = True
while True:
last_token = await self.store.get_federation_out_pos("events")
(
next_token,
event_to_received_ts,
) = await self.store.get_all_new_event_ids_stream(
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last_token, self._last_poked_id, limit=100
)
event_ids = event_to_received_ts.keys()
event_entries = await self.store.get_unredacted_events_from_cache_or_db(
event_ids
)
logger.debug(
"Handling %i -> %i: %i events to send (current id %i)",
last_token,
next_token,
len(event_entries),
self._last_poked_id,
)
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if not event_entries and next_token >= self._last_poked_id:
logger.debug("All events processed")
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break
async def handle_event(event: EventBase) -> None:
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# Only send events for this server.
send_on_behalf_of = event.internal_metadata.get_send_on_behalf_of()
is_mine = self.is_mine_id(event.sender)
if not is_mine and send_on_behalf_of is None:
logger.debug("Not sending remote-origin event %s", event)
return
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# We also want to not send out-of-band membership events.
#
# OOB memberships are used in three (and a half) situations:
#
# (1) invite events which we have received over federation. Those
# will have a `sender` on a different server, so will be
# skipped by the "is_mine" test above anyway.
#
# (2) rejections of invites to federated rooms - either remotely
# or locally generated. (Such rejections are normally
# created via federation, in which case the remote server is
# responsible for sending out the rejection. If that fails,
# we'll create a leave event locally, but that's only really
# for the benefit of the invited user - we don't have enough
# information to send it out over federation).
#
# (2a) rescinded knocks. These are identical to rejected invites.
#
# (3) knock events which we have sent over federation. As with
# invite rejections, the remote server should send them out to
# the federation.
#
# So, in all the above cases, we want to ignore such events.
#
# OOB memberships are always(?) outliers anyway, so if we *don't*
# ignore them, we'll get an exception further down when we try to
# fetch the membership list for the room.
#
# Arguably, we could equivalently ignore all outliers here, since
# in theory the only way for an outlier with a local `sender` to
# exist is by being an OOB membership (via one of (2), (2a) or (3)
# above).
#
if event.internal_metadata.is_out_of_band_membership():
logger.debug("Not sending OOB membership event %s", event)
return
# Finally, there are some other events that we should not send out
# until someone asks for them. They are explicitly flagged as such
# with `proactively_send: False`.
if not event.internal_metadata.should_proactively_send():
logger.debug(
"Not sending event with proactively_send=false: %s", event
)
return
destinations: Optional[Collection[str]] = None
if not event.prev_event_ids():
# If there are no prev event IDs then the state is empty
# and so no remote servers in the room
destinations = set()
if destinations is None:
# During partial join we use the set of servers that we got
# when beginning the join. It's still possible that we send
# events to servers that left the room in the meantime, but
# we consider that an acceptable risk since it is only our own
# events that we leak and not other server's ones.
partial_state_destinations = (
await self.store.get_partial_state_servers_at_join(
event.room_id
)
)
if partial_state_destinations is not None:
destinations = partial_state_destinations
if destinations is None:
# We check the external cache for the destinations, which is
# stored per state group.
sg = await self._external_cache.get(
"event_to_prev_state_group", event.event_id
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)
if sg:
destinations = await self._external_cache.get(
"get_joined_hosts", str(sg)
)
if destinations is None:
# Add logging to help track down #13444
logger.info(
"Unexpectedly did not have cached destinations for %s / %s",
sg,
event.event_id,
)
else:
# Add logging to help track down #13444
logger.info(
"Unexpectedly did not have cached prev group for %s",
event.event_id,
)
if destinations is None:
try:
# Get the state from before the event.
# We need to make sure that this is the state from before
# the event and not from after it.
# Otherwise if the last member on a server in a room is
# banned then it won't receive the event because it won't
# be in the room after the ban.
destinations = await self.state.get_hosts_in_room_at_events(
event.room_id, event_ids=event.prev_event_ids()
)
except Exception:
logger.exception(
"Failed to calculate hosts in room for event: %s",
event.event_id,
)
return
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sharded_destinations = {
d
for d in destinations
if self._federation_shard_config.should_handle(
self._instance_name, d
)
}
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if send_on_behalf_of is not None:
# If we are sending the event on behalf of another server
# then it already has the event and there is no reason to
# send the event to it.
sharded_destinations.discard(send_on_behalf_of)
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logger.debug("Sending %s to %r", event, sharded_destinations)
if sharded_destinations:
await self._send_pdu(event, sharded_destinations)
now = self.clock.time_msec()
ts = event_to_received_ts[event.event_id]
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assert ts is not None
synapse.metrics.event_processing_lag_by_event.labels(
"federation_sender"
).observe((now - ts) / 1000)
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async def handle_room_events(events: List[EventBase]) -> None:
logger.debug(
"Handling %i events in room %s", len(events), events[0].room_id
)
with Measure(self.clock, "handle_room_events"):
for event in events:
await handle_event(event)
events_by_room: Dict[str, List[EventBase]] = {}
for event_id in event_ids:
# `event_entries` is unsorted, so we have to iterate over `event_ids`
# to ensure the events are in the right order
event_cache = event_entries.get(event_id)
if event_cache:
event = event_cache.event
events_by_room.setdefault(event.room_id, []).append(event)
await make_deferred_yieldable(
defer.gatherResults(
[
run_in_background(handle_room_events, evs)
for evs in events_by_room.values()
],
consumeErrors=True,
)
)
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logger.debug("Successfully handled up to %i", next_token)
await self.store.update_federation_out_pos("events", next_token)
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if event_entries:
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now = self.clock.time_msec()
ts = max(t for t in event_to_received_ts.values() if t)
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assert ts is not None
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synapse.metrics.event_processing_lag.labels(
"federation_sender"
).set(now - ts)
synapse.metrics.event_processing_last_ts.labels(
"federation_sender"
).set(ts)
events_processed_counter.inc(len(event_entries))
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event_processing_loop_room_count.labels("federation_sender").inc(
len(events_by_room)
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)
event_processing_loop_counter.labels("federation_sender").inc()
synapse.metrics.event_processing_positions.labels(
"federation_sender"
).set(next_token)
finally:
self._is_processing = False
async def _send_pdu(self, pdu: EventBase, destinations: Iterable[str]) -> None:
# We loop through all destinations to see whether we already have
# a transaction in progress. If we do, stick it in the pending_pdus
# table and we'll get back to it later.
destinations = set(destinations)
destinations.discard(self.server_name)
logger.debug("Sending to: %s", str(destinations))
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if not destinations:
return
sent_pdus_destination_dist_total.inc(len(destinations))
sent_pdus_destination_dist_count.inc()
assert pdu.internal_metadata.stream_ordering
# track the fact that we have a PDU for these destinations,
# to allow us to perform catch-up later on if the remote is unreachable
# for a while.
await self.store.store_destination_rooms_entries(
destinations,
pdu.room_id,
pdu.internal_metadata.stream_ordering,
)
for destination in destinations:
self._get_per_destination_queue(destination).send_pdu(pdu)
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async def send_read_receipt(self, receipt: ReadReceipt) -> None:
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"""Send a RR to any other servers in the room
Args:
receipt: receipt to be sent
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"""
# Some background on the rate-limiting going on here.
#
# It turns out that if we attempt to send out RRs as soon as we get them from
# a client, then we end up trying to do several hundred Hz of federation
# transactions. (The number of transactions scales as O(N^2) on the size of a
# room, since in a large room we have both more RRs coming in, and more servers
# to send them to.)
#
# This leads to a lot of CPU load, and we end up getting behind. The solution
# currently adopted is as follows:
#
# The first receipt in a given room is sent out immediately, at time T0. Any
# further receipts are, in theory, batched up for N seconds, where N is calculated
# based on the number of servers in the room to achieve a transaction frequency
# of around 50Hz. So, for example, if there were 100 servers in the room, then
# N would be 100 / 50Hz = 2 seconds.
#
# Then, after T+N, we flush out any receipts that have accumulated, and restart
# the timer to flush out more receipts at T+2N, etc. If no receipts accumulate,
# we stop the cycle and go back to the start.
#
# However, in practice, it is often possible to flush out receipts earlier: in
# particular, if we are sending a transaction to a given server anyway (for
# example, because we have a PDU or a RR in another room to send), then we may
# as well send out all of the pending RRs for that server. So it may be that
# by the time we get to T+N, we don't actually have any RRs left to send out.
# Nevertheless we continue to buffer up RRs for the room in question until we
# reach the point that no RRs arrive between timer ticks.
#
# For even more background, see https://github.com/matrix-org/synapse/issues/4730.
room_id = receipt.room_id
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# Work out which remote servers should be poked and poke them.
domains_set = await self._storage_controllers.state.get_current_hosts_in_room_or_partial_state_approximation(
room_id
)
domains = [
d
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for d in domains_set
if not self.is_mine_server_name(d)
and self._federation_shard_config.should_handle(self._instance_name, d)
]
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if not domains:
return
queues_pending_flush = self._queues_awaiting_rr_flush_by_room.get(room_id)
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# if there is no flush yet scheduled, we will send out these receipts with
# immediate flushes, and schedule the next flush for this room.
if queues_pending_flush is not None:
logger.debug("Queuing receipt for: %r", domains)
else:
logger.debug("Sending receipt to: %r", domains)
self._schedule_rr_flush_for_room(room_id, len(domains))
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for domain in domains:
queue = self._get_per_destination_queue(domain)
queue.queue_read_receipt(receipt)
# if there is already a RR flush pending for this room, then make sure this
# destination is registered for the flush
if queues_pending_flush is not None:
queues_pending_flush.add(queue)
else:
queue.flush_read_receipts_for_room(room_id)
def _schedule_rr_flush_for_room(self, room_id: str, n_domains: int) -> None:
# that is going to cause approximately len(domains) transactions, so now back
# off for that multiplied by RR_TXN_INTERVAL_PER_ROOM
backoff_ms = self._rr_txn_interval_per_room_ms * n_domains
logger.debug("Scheduling RR flush in %s in %d ms", room_id, backoff_ms)
self.clock.call_later(backoff_ms, self._flush_rrs_for_room, room_id)
self._queues_awaiting_rr_flush_by_room[room_id] = set()
def _flush_rrs_for_room(self, room_id: str) -> None:
queues = self._queues_awaiting_rr_flush_by_room.pop(room_id)
logger.debug("Flushing RRs in %s to %s", room_id, queues)
if not queues:
# no more RRs arrived for this room; we are done.
return
# schedule the next flush
self._schedule_rr_flush_for_room(room_id, len(queues))
for queue in queues:
queue.flush_read_receipts_for_room(room_id)
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def send_presence_to_destinations(
Be smarter about which hosts to send presence to when processing room joins (#9402) This PR attempts to eliminate unnecessary presence sending work when your local server joins a room, or when a remote server joins a room your server is participating in by processing state deltas in chunks rather than individually. --- When your server joins a room for the first time, it requests the historical state as well. This chunk of new state is passed to the presence handler which, after filtering that state down to only membership joins, will send presence updates to homeservers for each join processed. It turns out that we were being a bit naive and processing each event individually, and sending out presence updates for every one of those joins. Even if many different joins were users on the same server (hello IRC bridges), we'd send presence to that same homeserver for every remote user join we saw. This PR attempts to deduplicate all of that by processing the entire batch of state deltas at once, instead of only doing each join individually. We process the joins and note down which servers need which presence: * If it was a local user join, send that user's latest presence to all servers in the room * If it was a remote user join, send the presence for all local users in the room to that homeserver We deduplicate by inserting all of those pending updates into a dictionary of the form: ``` { server_name1: {presence_update1, ...}, server_name2: {presence_update1, presence_update2, ...} } ``` Only after building this dict do we then start sending out presence updates.
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self, states: Iterable[UserPresenceState], destinations: Iterable[str]
) -> None:
"""Send the given presence states to the given destinations.
destinations (list[str])
"""
if not states or not self.hs.config.server.use_presence:
# No-op if presence is disabled.
return
# Ensure we only send out presence states for local users.
for state in states:
assert self.is_mine_id(state.user_id)
for destination in destinations:
if self.is_mine_server_name(destination):
continue
if not self._federation_shard_config.should_handle(
self._instance_name, destination
):
continue
self._get_per_destination_queue(destination).send_presence(
states, start_loop=False
)
self._destination_wakeup_queue.add_to_queue(destination)
def build_and_send_edu(
self,
destination: str,
edu_type: str,
content: JsonDict,
key: Optional[Hashable] = None,
) -> None:
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"""Construct an Edu object, and queue it for sending
Args:
destination: name of server to send to
edu_type: type of EDU to send
content: content of EDU
key: clobbering key for this edu
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"""
if self.is_mine_server_name(destination):
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logger.info("Not sending EDU to ourselves")
return
if not self._federation_shard_config.should_handle(
self._instance_name, destination
):
return
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edu = Edu(
origin=self.server_name,
destination=destination,
edu_type=edu_type,
content=content,
)
self.send_edu(edu, key)
def send_edu(self, edu: Edu, key: Optional[Hashable]) -> None:
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"""Queue an EDU for sending
Args:
edu: edu to send
key: clobbering key for this edu
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"""
if not self._federation_shard_config.should_handle(
self._instance_name, edu.destination
):
return
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queue = self._get_per_destination_queue(edu.destination)
if key:
queue.send_keyed_edu(edu, key)
else:
queue.send_edu(edu)
def send_device_messages(self, destination: str, immediate: bool = True) -> None:
if self.is_mine_server_name(destination):
logger.warning("Not sending device update to ourselves")
return
if not self._federation_shard_config.should_handle(
self._instance_name, destination
):
return
if immediate:
self._get_per_destination_queue(destination).attempt_new_transaction()
else:
self._get_per_destination_queue(destination).mark_new_data()
self._destination_wakeup_queue.add_to_queue(destination)
def wake_destination(self, destination: str) -> None:
"""Called when we want to retry sending transactions to a remote.
This is mainly useful if the remote server has been down and we think it
might have come back.
"""
if self.is_mine_server_name(destination):
logger.warning("Not waking up ourselves")
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return
if not self._federation_shard_config.should_handle(
self._instance_name, destination
):
return
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self._get_per_destination_queue(destination).attempt_new_transaction()
@staticmethod
def get_current_token() -> int:
# Dummy implementation for case where federation sender isn't offloaded
# to a worker.
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return 0
def federation_ack(self, instance_name: str, token: int) -> None:
# It is not expected that this gets called on FederationSender.
raise NotImplementedError()
@staticmethod
async def get_replication_rows(
instance_name: str, from_token: int, to_token: int, target_row_count: int
) -> Tuple[List[Tuple[int, Tuple]], int, bool]:
# Dummy implementation for case where federation sender isn't offloaded
# to a worker.
return [], 0, False
async def _wake_destinations_needing_catchup(self) -> None:
"""
Wakes up destinations that need catch-up and are not currently being
backed off from.
In order to reduce load spikes, adds a delay between each destination.
"""
last_processed: Optional[str] = None
while True:
destinations_to_wake = (
await self.store.get_catch_up_outstanding_destinations(last_processed)
)
if not destinations_to_wake:
# finished waking all destinations!
self._catchup_after_startup_timer = None
break
last_processed = destinations_to_wake[-1]
destinations_to_wake = [
d
for d in destinations_to_wake
if self._federation_shard_config.should_handle(self._instance_name, d)
]
for destination in destinations_to_wake:
logger.info(
"Destination %s has outstanding catch-up, waking up.",
last_processed,
)
self.wake_destination(destination)
await self.clock.sleep(CATCH_UP_STARTUP_INTERVAL_SEC)