synapse-product/synapse/federation/sender/per_destination_queue.py

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# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# 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.
import datetime
import logging
from typing import TYPE_CHECKING, Dict, Hashable, Iterable, List, Optional, Tuple, cast
from prometheus_client import Counter
from synapse.api.errors import (
FederationDeniedError,
HttpResponseException,
RequestSendFailed,
)
from synapse.api.presence import UserPresenceState
from synapse.events import EventBase
from synapse.federation.units import Edu
from synapse.handlers.presence import format_user_presence_state
from synapse.metrics import sent_transactions_counter
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.types import ReadReceipt
from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter
if TYPE_CHECKING:
import synapse.server
# This is defined in the Matrix spec and enforced by the receiver.
MAX_EDUS_PER_TRANSACTION = 100
logger = logging.getLogger(__name__)
sent_edus_counter = Counter(
"synapse_federation_client_sent_edus", "Total number of EDUs successfully sent"
)
sent_edus_by_type = Counter(
"synapse_federation_client_sent_edus_by_type",
"Number of sent EDUs successfully sent, by event type",
["type"],
)
class PerDestinationQueue:
"""
Manages the per-destination transmission queues.
Args:
hs
transaction_sender
destination: the server_name of the destination that we are managing
transmission for.
"""
def __init__(
self,
hs: "synapse.server.HomeServer",
transaction_manager: "synapse.federation.sender.TransactionManager",
destination: str,
):
self._server_name = hs.hostname
self._clock = hs.get_clock()
self._store = hs.get_datastore()
self._transaction_manager = transaction_manager
self._instance_name = hs.get_instance_name()
self._federation_shard_config = hs.config.worker.federation_shard_config
self._should_send_on_this_instance = True
if not self._federation_shard_config.should_handle(
self._instance_name, destination
):
# We don't raise an exception here to avoid taking out any other
# processing. We have a guard in `attempt_new_transaction` that
# ensure we don't start sending stuff.
logger.error(
"Create a per destination queue for %s on wrong worker", destination,
)
self._should_send_on_this_instance = False
self._destination = destination
self.transmission_loop_running = False
# True whilst we are sending events that the remote homeserver missed
# because it was unreachable. We start in this state so we can perform
# catch-up at startup.
# New events will only be sent once this is finished, at which point
# _catching_up is flipped to False.
self._catching_up = True # type: bool
# The stream_ordering of the most recent PDU that was discarded due to
# being in catch-up mode.
self._catchup_last_skipped = 0 # type: int
# Cache of the last successfully-transmitted stream ordering for this
# destination (we are the only updater so this is safe)
self._last_successful_stream_ordering = None # type: Optional[int]
# a list of pending PDUs
self._pending_pdus = [] # type: List[EventBase]
# XXX this is never actually used: see
# https://github.com/matrix-org/synapse/issues/7549
self._pending_edus = [] # type: List[Edu]
# Pending EDUs by their "key". Keyed EDUs are EDUs that get clobbered
# based on their key (e.g. typing events by room_id)
# Map of (edu_type, key) -> Edu
self._pending_edus_keyed = {} # type: Dict[Tuple[str, Hashable], Edu]
# Map of user_id -> UserPresenceState of pending presence to be sent to this
# destination
self._pending_presence = {} # type: Dict[str, UserPresenceState]
# room_id -> receipt_type -> user_id -> receipt_dict
self._pending_rrs = {} # type: Dict[str, Dict[str, Dict[str, dict]]]
self._rrs_pending_flush = False
# stream_id of last successfully sent to-device message.
# NB: may be a long or an int.
self._last_device_stream_id = 0
# stream_id of last successfully sent device list update.
self._last_device_list_stream_id = 0
def __str__(self) -> str:
return "PerDestinationQueue[%s]" % self._destination
def pending_pdu_count(self) -> int:
return len(self._pending_pdus)
def pending_edu_count(self) -> int:
return (
len(self._pending_edus)
+ len(self._pending_presence)
+ len(self._pending_edus_keyed)
)
def send_pdu(self, pdu: EventBase) -> None:
"""Add a PDU to the queue, and start the transmission loop if necessary
Args:
pdu: pdu to send
"""
if not self._catching_up or self._last_successful_stream_ordering is None:
# only enqueue the PDU if we are not catching up (False) or do not
# yet know if we have anything to catch up (None)
self._pending_pdus.append(pdu)
else:
self._catchup_last_skipped = pdu.internal_metadata.stream_ordering
self.attempt_new_transaction()
def send_presence(self, states: Iterable[UserPresenceState]) -> None:
"""Add presence updates to the queue. Start the transmission loop if necessary.
Args:
states: presence to send
"""
self._pending_presence.update({state.user_id: state for state in states})
self.attempt_new_transaction()
def queue_read_receipt(self, receipt: ReadReceipt) -> None:
"""Add a RR to the list to be sent. Doesn't start the transmission loop yet
(see flush_read_receipts_for_room)
Args:
receipt: receipt to be queued
"""
self._pending_rrs.setdefault(receipt.room_id, {}).setdefault(
receipt.receipt_type, {}
)[receipt.user_id] = {"event_ids": receipt.event_ids, "data": receipt.data}
def flush_read_receipts_for_room(self, room_id: str) -> None:
# if we don't have any read-receipts for this room, it may be that we've already
# sent them out, so we don't need to flush.
if room_id not in self._pending_rrs:
return
self._rrs_pending_flush = True
self.attempt_new_transaction()
def send_keyed_edu(self, edu: Edu, key: Hashable) -> None:
self._pending_edus_keyed[(edu.edu_type, key)] = edu
self.attempt_new_transaction()
def send_edu(self, edu) -> None:
self._pending_edus.append(edu)
self.attempt_new_transaction()
def attempt_new_transaction(self) -> None:
"""Try to start a new transaction to this destination
If there is already a transaction in progress to this destination,
returns immediately. Otherwise kicks off the process of sending a
transaction in the background.
"""
if self.transmission_loop_running:
# XXX: this can get stuck on by a never-ending
# request at which point pending_pdus just keeps growing.
# we need application-layer timeouts of some flavour of these
# requests
logger.debug("TX [%s] Transaction already in progress", self._destination)
return
if not self._should_send_on_this_instance:
# We don't raise an exception here to avoid taking out any other
# processing.
logger.error(
"Trying to start a transaction to %s on wrong worker", self._destination
)
return
logger.debug("TX [%s] Starting transaction loop", self._destination)
run_as_background_process(
"federation_transaction_transmission_loop",
self._transaction_transmission_loop,
)
async def _transaction_transmission_loop(self) -> None:
pending_pdus = [] # type: List[EventBase]
try:
self.transmission_loop_running = True
# This will throw if we wouldn't retry. We do this here so we fail
# quickly, but we will later check this again in the http client,
# hence why we throw the result away.
await get_retry_limiter(self._destination, self._clock, self._store)
if self._catching_up:
# we potentially need to catch-up first
await self._catch_up_transmission_loop()
if self._catching_up:
# not caught up yet
return
pending_pdus = []
while True:
# We have to keep 2 free slots for presence and rr_edus
limit = MAX_EDUS_PER_TRANSACTION - 2
device_update_edus, dev_list_id = await self._get_device_update_edus(
limit
)
limit -= len(device_update_edus)
(
to_device_edus,
device_stream_id,
) = await self._get_to_device_message_edus(limit)
pending_edus = device_update_edus + to_device_edus
# BEGIN CRITICAL SECTION
#
# In order to avoid a race condition, we need to make sure that
# the following code (from popping the queues up to the point
# where we decide if we actually have any pending messages) is
# atomic - otherwise new PDUs or EDUs might arrive in the
# meantime, but not get sent because we hold the
# transmission_loop_running flag.
pending_pdus = self._pending_pdus
# We can only include at most 50 PDUs per transactions
pending_pdus, self._pending_pdus = pending_pdus[:50], pending_pdus[50:]
pending_edus.extend(self._get_rr_edus(force_flush=False))
pending_presence = self._pending_presence
self._pending_presence = {}
if pending_presence:
pending_edus.append(
Edu(
origin=self._server_name,
destination=self._destination,
edu_type="m.presence",
content={
"push": [
format_user_presence_state(
presence, self._clock.time_msec()
)
for presence in pending_presence.values()
]
},
)
)
pending_edus.extend(
self._pop_pending_edus(MAX_EDUS_PER_TRANSACTION - len(pending_edus))
)
while (
len(pending_edus) < MAX_EDUS_PER_TRANSACTION
and self._pending_edus_keyed
):
_, val = self._pending_edus_keyed.popitem()
pending_edus.append(val)
if pending_pdus:
logger.debug(
"TX [%s] len(pending_pdus_by_dest[dest]) = %d",
self._destination,
len(pending_pdus),
)
if not pending_pdus and not pending_edus:
logger.debug("TX [%s] Nothing to send", self._destination)
self._last_device_stream_id = device_stream_id
return
# if we've decided to send a transaction anyway, and we have room, we
# may as well send any pending RRs
if len(pending_edus) < MAX_EDUS_PER_TRANSACTION:
pending_edus.extend(self._get_rr_edus(force_flush=True))
# END CRITICAL SECTION
success = await self._transaction_manager.send_new_transaction(
self._destination, pending_pdus, pending_edus
)
if success:
sent_transactions_counter.inc()
sent_edus_counter.inc(len(pending_edus))
for edu in pending_edus:
sent_edus_by_type.labels(edu.edu_type).inc()
# Remove the acknowledged device messages from the database
# Only bother if we actually sent some device messages
if to_device_edus:
await self._store.delete_device_msgs_for_remote(
self._destination, device_stream_id
)
# also mark the device updates as sent
if device_update_edus:
logger.info(
"Marking as sent %r %r", self._destination, dev_list_id
)
await self._store.mark_as_sent_devices_by_remote(
self._destination, dev_list_id
)
self._last_device_stream_id = device_stream_id
self._last_device_list_stream_id = dev_list_id
if pending_pdus:
# we sent some PDUs and it was successful, so update our
# last_successful_stream_ordering in the destinations table.
final_pdu = pending_pdus[-1]
last_successful_stream_ordering = (
final_pdu.internal_metadata.stream_ordering
)
await self._store.set_destination_last_successful_stream_ordering(
self._destination, last_successful_stream_ordering
)
else:
break
except NotRetryingDestination as e:
logger.debug(
"TX [%s] not ready for retry yet (next retry at %s) - "
"dropping transaction for now",
self._destination,
datetime.datetime.fromtimestamp(
(e.retry_last_ts + e.retry_interval) / 1000.0
),
)
if e.retry_interval > 60 * 60 * 1000:
# we won't retry for another hour!
# (this suggests a significant outage)
# We drop pending EDUs because otherwise they will
# rack up indefinitely.
# (Dropping PDUs is already performed by `_start_catching_up`.)
# Note that:
# - the EDUs that are being dropped here are those that we can
# afford to drop (specifically, only typing notifications,
# read receipts and presence updates are being dropped here)
# - Other EDUs such as to_device messages are queued with a
# different mechanism
# - this is all volatile state that would be lost if the
# federation sender restarted anyway
# dropping read receipts is a bit sad but should be solved
# through another mechanism, because this is all volatile!
self._pending_edus = []
self._pending_edus_keyed = {}
self._pending_presence = {}
self._pending_rrs = {}
self._start_catching_up()
except FederationDeniedError as e:
logger.info(e)
except HttpResponseException as e:
logger.warning(
"TX [%s] Received %d response to transaction: %s",
self._destination,
e.code,
e,
)
self._start_catching_up()
except RequestSendFailed as e:
logger.warning(
"TX [%s] Failed to send transaction: %s", self._destination, e
)
for p in pending_pdus:
logger.info(
"Failed to send event %s to %s", p.event_id, self._destination
)
self._start_catching_up()
except Exception:
logger.exception("TX [%s] Failed to send transaction", self._destination)
for p in pending_pdus:
logger.info(
"Failed to send event %s to %s", p.event_id, self._destination
)
self._start_catching_up()
finally:
# We want to be *very* sure we clear this after we stop processing
self.transmission_loop_running = False
async def _catch_up_transmission_loop(self) -> None:
first_catch_up_check = self._last_successful_stream_ordering is None
if first_catch_up_check:
# first catchup so get last_successful_stream_ordering from database
self._last_successful_stream_ordering = await self._store.get_destination_last_successful_stream_ordering(
self._destination
)
if self._last_successful_stream_ordering is None:
# if it's still None, then this means we don't have the information
# in our database ­ we haven't successfully sent a PDU to this server
# (at least since the introduction of the feature tracking
# last_successful_stream_ordering).
# Sadly, this means we can't do anything here as we don't know what
# needs catching up — so catching up is futile; let's stop.
self._catching_up = False
return
# get at most 50 catchup room/PDUs
while True:
event_ids = await self._store.get_catch_up_room_event_ids(
self._destination, self._last_successful_stream_ordering,
)
if not event_ids:
# No more events to catch up on, but we can't ignore the chance
# of a race condition, so we check that no new events have been
# skipped due to us being in catch-up mode
if self._catchup_last_skipped > self._last_successful_stream_ordering:
# another event has been skipped because we were in catch-up mode
continue
# we are done catching up!
self._catching_up = False
break
if first_catch_up_check:
# as this is our check for needing catch-up, we may have PDUs in
# the queue from before we *knew* we had to do catch-up, so
# clear those out now.
self._start_catching_up()
# fetch the relevant events from the event store
# - redacted behaviour of REDACT is fine, since we only send metadata
# of redacted events to the destination.
# - don't need to worry about rejected events as we do not actively
# forward received events over federation.
catchup_pdus = await self._store.get_events_as_list(event_ids)
if not catchup_pdus:
raise AssertionError(
"No events retrieved when we asked for %r. "
"This should not happen." % event_ids
)
if logger.isEnabledFor(logging.INFO):
rooms = (p.room_id for p in catchup_pdus)
logger.info("Catching up rooms to %s: %r", self._destination, rooms)
success = await self._transaction_manager.send_new_transaction(
self._destination, catchup_pdus, []
)
if not success:
return
sent_transactions_counter.inc()
final_pdu = catchup_pdus[-1]
self._last_successful_stream_ordering = cast(
int, final_pdu.internal_metadata.stream_ordering
)
await self._store.set_destination_last_successful_stream_ordering(
self._destination, self._last_successful_stream_ordering
)
def _get_rr_edus(self, force_flush: bool) -> Iterable[Edu]:
if not self._pending_rrs:
return
if not force_flush and not self._rrs_pending_flush:
# not yet time for this lot
return
edu = Edu(
origin=self._server_name,
destination=self._destination,
edu_type="m.receipt",
content=self._pending_rrs,
)
self._pending_rrs = {}
self._rrs_pending_flush = False
yield edu
def _pop_pending_edus(self, limit: int) -> List[Edu]:
pending_edus = self._pending_edus
pending_edus, self._pending_edus = pending_edus[:limit], pending_edus[limit:]
return pending_edus
async def _get_device_update_edus(self, limit: int) -> Tuple[List[Edu], int]:
last_device_list = self._last_device_list_stream_id
# Retrieve list of new device updates to send to the destination
now_stream_id, results = await self._store.get_device_updates_by_remote(
self._destination, last_device_list, limit=limit
)
edus = [
Edu(
origin=self._server_name,
destination=self._destination,
edu_type=edu_type,
content=content,
)
for (edu_type, content) in results
]
assert len(edus) <= limit, "get_device_updates_by_remote returned too many EDUs"
return (edus, now_stream_id)
async def _get_to_device_message_edus(self, limit: int) -> Tuple[List[Edu], int]:
last_device_stream_id = self._last_device_stream_id
to_device_stream_id = self._store.get_to_device_stream_token()
contents, stream_id = await self._store.get_new_device_msgs_for_remote(
self._destination, last_device_stream_id, to_device_stream_id, limit
)
edus = [
Edu(
origin=self._server_name,
destination=self._destination,
edu_type="m.direct_to_device",
content=content,
)
for content in contents
]
return (edus, stream_id)
def _start_catching_up(self) -> None:
"""
Marks this destination as being in catch-up mode.
This throws away the PDU queue.
"""
self._catching_up = True
self._pending_pdus = []