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forked-synapse/synapse/handlers/presence.py
Patrick Cloke efd4d06d76
Clean-up presence code (#16092) 
Misc. clean-ups to:

* Use keyword arguments.
* Return early (reducing indentation) of some functions.
* Removing duplicated / unused code.
* Use wrap_as_background_process.
2023-08-10 07:39:46 -04:00

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# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2020 The Matrix.org Foundation C.I.C.
#
# 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 is responsible for keeping track of presence status of local
and remote users.
The methods that define policy are:
- PresenceHandler._update_states
- PresenceHandler._handle_timeouts
- should_notify
"""
import abc
import contextlib
import logging
from bisect import bisect
from contextlib import contextmanager
from types import TracebackType
from typing import (
TYPE_CHECKING,
Any,
Callable,
Collection,
Dict,
Generator,
Iterable,
List,
Optional,
Set,
Tuple,
Type,
)
from prometheus_client import Counter
from typing_extensions import ContextManager
import synapse.metrics
from synapse.api.constants import EduTypes, EventTypes, Membership, PresenceState
from synapse.api.errors import SynapseError
from synapse.api.presence import UserPresenceState
from synapse.appservice import ApplicationService
from synapse.events.presence_router import PresenceRouter
from synapse.logging.context import run_in_background
from synapse.metrics import LaterGauge
from synapse.metrics.background_process_metrics import (
run_as_background_process,
wrap_as_background_process,
)
from synapse.replication.http.presence import (
ReplicationBumpPresenceActiveTime,
ReplicationPresenceSetState,
)
from synapse.replication.http.streams import ReplicationGetStreamUpdates
from synapse.replication.tcp.commands import ClearUserSyncsCommand
from synapse.replication.tcp.streams import PresenceFederationStream, PresenceStream
from synapse.storage.databases.main import DataStore
from synapse.streams import EventSource
from synapse.types import (
JsonDict,
StrCollection,
StreamKeyType,
UserID,
get_domain_from_id,
)
from synapse.util.async_helpers import Linearizer
from synapse.util.metrics import Measure
from synapse.util.wheel_timer import WheelTimer
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
notified_presence_counter = Counter("synapse_handler_presence_notified_presence", "")
federation_presence_out_counter = Counter(
"synapse_handler_presence_federation_presence_out", ""
)
presence_updates_counter = Counter("synapse_handler_presence_presence_updates", "")
timers_fired_counter = Counter("synapse_handler_presence_timers_fired", "")
federation_presence_counter = Counter(
"synapse_handler_presence_federation_presence", ""
)
bump_active_time_counter = Counter("synapse_handler_presence_bump_active_time", "")
get_updates_counter = Counter("synapse_handler_presence_get_updates", "", ["type"])
notify_reason_counter = Counter(
"synapse_handler_presence_notify_reason", "", ["locality", "reason"]
)
state_transition_counter = Counter(
"synapse_handler_presence_state_transition", "", ["locality", "from", "to"]
)
# If a user was last active in the last LAST_ACTIVE_GRANULARITY, consider them
# "currently_active"
LAST_ACTIVE_GRANULARITY = 60 * 1000
# How long to wait until a new /events or /sync request before assuming
# the client has gone.
SYNC_ONLINE_TIMEOUT = 30 * 1000
# How long to wait before marking the user as idle. Compared against last active
IDLE_TIMER = 5 * 60 * 1000
# How often we expect remote servers to resend us presence.
FEDERATION_TIMEOUT = 30 * 60 * 1000
# How often to resend presence to remote servers
FEDERATION_PING_INTERVAL = 25 * 60 * 1000
# How long we will wait before assuming that the syncs from an external process
# are dead.
EXTERNAL_PROCESS_EXPIRY = 5 * 60 * 1000
# Delay before a worker tells the presence handler that a user has stopped
# syncing.
UPDATE_SYNCING_USERS_MS = 10 * 1000
assert LAST_ACTIVE_GRANULARITY < IDLE_TIMER
class BasePresenceHandler(abc.ABC):
"""Parts of the PresenceHandler that are shared between workers and presence
writer"""
def __init__(self, hs: "HomeServer"):
self.clock = hs.get_clock()
self.store = hs.get_datastores().main
self._storage_controllers = hs.get_storage_controllers()
self.presence_router = hs.get_presence_router()
self.state = hs.get_state_handler()
self.is_mine_id = hs.is_mine_id
self._presence_enabled = hs.config.server.use_presence
self._federation = None
if hs.should_send_federation():
self._federation = hs.get_federation_sender()
self._federation_queue = PresenceFederationQueue(hs, self)
self._busy_presence_enabled = hs.config.experimental.msc3026_enabled
self.VALID_PRESENCE: Tuple[str, ...] = (
PresenceState.ONLINE,
PresenceState.UNAVAILABLE,
PresenceState.OFFLINE,
)
if self._busy_presence_enabled:
self.VALID_PRESENCE += (PresenceState.BUSY,)
active_presence = self.store.take_presence_startup_info()
self.user_to_current_state = {state.user_id: state for state in active_presence}
@abc.abstractmethod
async def user_syncing(
self, user_id: str, affect_presence: bool, presence_state: str
) -> ContextManager[None]:
"""Returns a context manager that should surround any stream requests
from the user.
This allows us to keep track of who is currently streaming and who isn't
without having to have timers outside of this module to avoid flickering
when users disconnect/reconnect.
Args:
user_id: the user that is starting a sync
affect_presence: If false this function will be a no-op.
Useful for streams that are not associated with an actual
client that is being used by a user.
presence_state: The presence state indicated in the sync request
"""
@abc.abstractmethod
def get_currently_syncing_users_for_replication(self) -> Iterable[str]:
"""Get an iterable of syncing users on this worker, to send to the presence handler
This is called when a replication connection is established. It should return
a list of user ids, which are then sent as USER_SYNC commands to inform the
process handling presence about those users.
Returns:
An iterable of user_id strings.
"""
async def get_state(self, target_user: UserID) -> UserPresenceState:
results = await self.get_states([target_user.to_string()])
return results[0]
async def get_states(
self, target_user_ids: Iterable[str]
) -> List[UserPresenceState]:
"""Get the presence state for users."""
updates_d = await self.current_state_for_users(target_user_ids)
updates = list(updates_d.values())
for user_id in set(target_user_ids) - {u.user_id for u in updates}:
updates.append(UserPresenceState.default(user_id))
return updates
async def current_state_for_users(
self, user_ids: Iterable[str]
) -> Dict[str, UserPresenceState]:
"""Get the current presence state for multiple users.
Returns:
A mapping of `user_id` -> `UserPresenceState`
"""
states = {}
missing = []
for user_id in user_ids:
state = self.user_to_current_state.get(user_id, None)
if state:
states[user_id] = state
else:
missing.append(user_id)
if missing:
# There are things not in our in memory cache. Lets pull them out of
# the database.
res = await self.store.get_presence_for_users(missing)
states.update(res)
for user_id in missing:
# if user has no state in database, create the state
if not res.get(user_id, None):
new_state = UserPresenceState.default(user_id)
states[user_id] = new_state
self.user_to_current_state[user_id] = new_state
return states
async def current_state_for_user(self, user_id: str) -> UserPresenceState:
"""Get the current presence state for a user."""
res = await self.current_state_for_users([user_id])
return res[user_id]
@abc.abstractmethod
async def set_state(
self,
target_user: UserID,
state: JsonDict,
ignore_status_msg: bool = False,
force_notify: bool = False,
) -> None:
"""Set the presence state of the user.
Args:
target_user: The ID of the user to set the presence state of.
state: The presence state as a JSON dictionary.
ignore_status_msg: True to ignore the "status_msg" field of the `state` dict.
If False, the user's current status will be updated.
force_notify: Whether to force notification of the update to clients.
"""
@abc.abstractmethod
async def bump_presence_active_time(self, user: UserID) -> None:
"""We've seen the user do something that indicates they're interacting
with the app.
"""
async def update_external_syncs_row( # noqa: B027 (no-op by design)
self, process_id: str, user_id: str, is_syncing: bool, sync_time_msec: int
) -> None:
"""Update the syncing users for an external process as a delta.
This is a no-op when presence is handled by a different worker.
Args:
process_id: An identifier for the process the users are
syncing against. This allows synapse to process updates
as user start and stop syncing against a given process.
user_id: The user who has started or stopped syncing
is_syncing: Whether or not the user is now syncing
sync_time_msec: Time in ms when the user was last syncing
"""
async def update_external_syncs_clear( # noqa: B027 (no-op by design)
self, process_id: str
) -> None:
"""Marks all users that had been marked as syncing by a given process
as offline.
Used when the process has stopped/disappeared.
This is a no-op when presence is handled by a different worker.
"""
async def process_replication_rows(
self, stream_name: str, instance_name: str, token: int, rows: list
) -> None:
"""Process streams received over replication."""
await self._federation_queue.process_replication_rows(
stream_name, instance_name, token, rows
)
def get_federation_queue(self) -> "PresenceFederationQueue":
"""Get the presence federation queue."""
return self._federation_queue
async def maybe_send_presence_to_interested_destinations(
self, states: List[UserPresenceState]
) -> None:
"""If this instance is a federation sender, send the states to all
destinations that are interested. Filters out any states for remote
users.
"""
if not self._federation:
return
states = [s for s in states if self.is_mine_id(s.user_id)]
if not states:
return
hosts_to_states = await get_interested_remotes(
self.store,
self.presence_router,
states,
)
for destination, host_states in hosts_to_states.items():
self._federation.send_presence_to_destinations(host_states, [destination])
async def send_full_presence_to_users(self, user_ids: StrCollection) -> None:
"""
Adds to the list of users who should receive a full snapshot of presence
upon their next sync. Note that this only works for local users.
Then, grabs the current presence state for a given set of users and adds it
to the top of the presence stream.
Args:
user_ids: The IDs of the local users to send full presence to.
"""
# Retrieve one of the users from the given set
if not user_ids:
raise Exception(
"send_full_presence_to_users must be called with at least one user"
)
user_id = next(iter(user_ids))
# Mark all users as receiving full presence on their next sync
await self.store.add_users_to_send_full_presence_to(user_ids)
# Add a new entry to the presence stream. Since we use stream tokens to determine whether a
# local user should receive a full snapshot of presence when they sync, we need to bump the
# presence stream so that subsequent syncs with no presence activity in between won't result
# in the client receiving multiple full snapshots of presence.
#
# If we bump the stream ID, then the user will get a higher stream token next sync, and thus
# correctly won't receive a second snapshot.
# Get the current presence state for one of the users (defaults to offline if not found)
current_presence_state = await self.get_state(UserID.from_string(user_id))
# Convert the UserPresenceState object into a serializable dict
state = {
"presence": current_presence_state.state,
"status_message": current_presence_state.status_msg,
}
# Copy the presence state to the tip of the presence stream.
# We set force_notify=True here so that this presence update is guaranteed to
# increment the presence stream ID (which resending the current user's presence
# otherwise would not do).
await self.set_state(UserID.from_string(user_id), state, force_notify=True)
async def is_visible(self, observed_user: UserID, observer_user: UserID) -> bool:
raise NotImplementedError(
"Attempting to check presence on a non-presence worker."
)
class _NullContextManager(ContextManager[None]):
"""A context manager which does nothing."""
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> None:
pass
class WorkerPresenceHandler(BasePresenceHandler):
def __init__(self, hs: "HomeServer"):
super().__init__(hs)
self.hs = hs
self._presence_writer_instance = hs.config.worker.writers.presence[0]
# Route presence EDUs to the right worker
hs.get_federation_registry().register_instances_for_edu(
EduTypes.PRESENCE,
hs.config.worker.writers.presence,
)
# The number of ongoing syncs on this process, by user id.
# Empty if _presence_enabled is false.
self._user_to_num_current_syncs: Dict[str, int] = {}
self.notifier = hs.get_notifier()
self.instance_id = hs.get_instance_id()
# user_id -> last_sync_ms. Lists the users that have stopped syncing but
# we haven't notified the presence writer of that yet
self.users_going_offline: Dict[str, int] = {}
self._bump_active_client = ReplicationBumpPresenceActiveTime.make_client(hs)
self._set_state_client = ReplicationPresenceSetState.make_client(hs)
self._send_stop_syncing_loop = self.clock.looping_call(
self.send_stop_syncing, UPDATE_SYNCING_USERS_MS
)
hs.get_reactor().addSystemEventTrigger(
"before",
"shutdown",
run_as_background_process,
"generic_presence.on_shutdown",
self._on_shutdown,
)
async def _on_shutdown(self) -> None:
if self._presence_enabled:
self.hs.get_replication_command_handler().send_command(
ClearUserSyncsCommand(self.instance_id)
)
def send_user_sync(self, user_id: str, is_syncing: bool, last_sync_ms: int) -> None:
if self._presence_enabled:
self.hs.get_replication_command_handler().send_user_sync(
self.instance_id, user_id, is_syncing, last_sync_ms
)
def mark_as_coming_online(self, user_id: str) -> None:
"""A user has started syncing. Send a UserSync to the presence writer,
unless they had recently stopped syncing.
"""
going_offline = self.users_going_offline.pop(user_id, None)
if not going_offline:
# Safe to skip because we haven't yet told the presence writer they
# were offline
self.send_user_sync(user_id, True, self.clock.time_msec())
def mark_as_going_offline(self, user_id: str) -> None:
"""A user has stopped syncing. We wait before notifying the presence
writer as its likely they'll come back soon. This allows us to avoid
sending a stopped syncing immediately followed by a started syncing
notification to the presence writer
"""
self.users_going_offline[user_id] = self.clock.time_msec()
def send_stop_syncing(self) -> None:
"""Check if there are any users who have stopped syncing a while ago and
haven't come back yet. If there are poke the presence writer about them.
"""
now = self.clock.time_msec()
for user_id, last_sync_ms in list(self.users_going_offline.items()):
if now - last_sync_ms > UPDATE_SYNCING_USERS_MS:
self.users_going_offline.pop(user_id, None)
self.send_user_sync(user_id, False, last_sync_ms)
async def user_syncing(
self, user_id: str, affect_presence: bool, presence_state: str
) -> ContextManager[None]:
"""Record that a user is syncing.
Called by the sync and events servlets to record that a user has connected to
this worker and is waiting for some events.
"""
if not affect_presence or not self._presence_enabled:
return _NullContextManager()
prev_state = await self.current_state_for_user(user_id)
if prev_state.state != PresenceState.BUSY:
# We set state here but pass ignore_status_msg = True as we don't want to
# cause the status message to be cleared.
# Note that this causes last_active_ts to be incremented which is not
# what the spec wants: see comment in the BasePresenceHandler version
# of this function.
await self.set_state(
UserID.from_string(user_id),
{"presence": presence_state},
ignore_status_msg=True,
)
curr_sync = self._user_to_num_current_syncs.get(user_id, 0)
self._user_to_num_current_syncs[user_id] = curr_sync + 1
# If we went from no in flight sync to some, notify replication
if self._user_to_num_current_syncs[user_id] == 1:
self.mark_as_coming_online(user_id)
def _end() -> None:
# We check that the user_id is in user_to_num_current_syncs because
# user_to_num_current_syncs may have been cleared if we are
# shutting down.
if user_id in self._user_to_num_current_syncs:
self._user_to_num_current_syncs[user_id] -= 1
# If we went from one in flight sync to non, notify replication
if self._user_to_num_current_syncs[user_id] == 0:
self.mark_as_going_offline(user_id)
@contextlib.contextmanager
def _user_syncing() -> Generator[None, None, None]:
try:
yield
finally:
_end()
return _user_syncing()
async def notify_from_replication(
self, states: List[UserPresenceState], stream_id: int
) -> None:
parties = await get_interested_parties(self.store, self.presence_router, states)
room_ids_to_states, users_to_states = parties
self.notifier.on_new_event(
StreamKeyType.PRESENCE,
stream_id,
rooms=room_ids_to_states.keys(),
users=users_to_states.keys(),
)
async def process_replication_rows(
self, stream_name: str, instance_name: str, token: int, rows: list
) -> None:
await super().process_replication_rows(stream_name, instance_name, token, rows)
if stream_name != PresenceStream.NAME:
return
states = [
UserPresenceState(
row.user_id,
row.state,
row.last_active_ts,
row.last_federation_update_ts,
row.last_user_sync_ts,
row.status_msg,
row.currently_active,
)
for row in rows
]
# The list of states to notify sync streams and remote servers about.
# This is calculated by comparing the old and new states for each user
# using `should_notify(..)`.
#
# Note that this is necessary as the presence writer will periodically
# flush presence state changes that should not be notified about to the
# DB, and so will be sent over the replication stream.
state_to_notify = []
for new_state in states:
old_state = self.user_to_current_state.get(new_state.user_id)
self.user_to_current_state[new_state.user_id] = new_state
is_mine = self.is_mine_id(new_state.user_id)
if not old_state or should_notify(old_state, new_state, is_mine):
state_to_notify.append(new_state)
stream_id = token
await self.notify_from_replication(state_to_notify, stream_id)
# If this is a federation sender, notify about presence updates.
await self.maybe_send_presence_to_interested_destinations(state_to_notify)
def get_currently_syncing_users_for_replication(self) -> Iterable[str]:
return [
user_id
for user_id, count in self._user_to_num_current_syncs.items()
if count > 0
]
async def set_state(
self,
target_user: UserID,
state: JsonDict,
ignore_status_msg: bool = False,
force_notify: bool = False,
) -> None:
"""Set the presence state of the user.
Args:
target_user: The ID of the user to set the presence state of.
state: The presence state as a JSON dictionary.
ignore_status_msg: True to ignore the "status_msg" field of the `state` dict.
If False, the user's current status will be updated.
force_notify: Whether to force notification of the update to clients.
"""
presence = state["presence"]
if presence not in self.VALID_PRESENCE:
raise SynapseError(400, "Invalid presence state")
user_id = target_user.to_string()
# If presence is disabled, no-op
if not self._presence_enabled:
return
# Proxy request to instance that writes presence
await self._set_state_client(
instance_name=self._presence_writer_instance,
user_id=user_id,
state=state,
ignore_status_msg=ignore_status_msg,
force_notify=force_notify,
)
async def bump_presence_active_time(self, user: UserID) -> None:
"""We've seen the user do something that indicates they're interacting
with the app.
"""
# If presence is disabled, no-op
if not self._presence_enabled:
return
# Proxy request to instance that writes presence
user_id = user.to_string()
await self._bump_active_client(
instance_name=self._presence_writer_instance, user_id=user_id
)
class PresenceHandler(BasePresenceHandler):
def __init__(self, hs: "HomeServer"):
super().__init__(hs)
self.hs = hs
self.wheel_timer: WheelTimer[str] = WheelTimer()
self.notifier = hs.get_notifier()
federation_registry = hs.get_federation_registry()
federation_registry.register_edu_handler(
EduTypes.PRESENCE, self.incoming_presence
)
LaterGauge(
"synapse_handlers_presence_user_to_current_state_size",
"",
[],
lambda: len(self.user_to_current_state),
)
now = self.clock.time_msec()
if self._presence_enabled:
for state in self.user_to_current_state.values():
self.wheel_timer.insert(
now=now, obj=state.user_id, then=state.last_active_ts + IDLE_TIMER
)
self.wheel_timer.insert(
now=now,
obj=state.user_id,
then=state.last_user_sync_ts + SYNC_ONLINE_TIMEOUT,
)
if self.is_mine_id(state.user_id):
self.wheel_timer.insert(
now=now,
obj=state.user_id,
then=state.last_federation_update_ts + FEDERATION_PING_INTERVAL,
)
else:
self.wheel_timer.insert(
now=now,
obj=state.user_id,
then=state.last_federation_update_ts + FEDERATION_TIMEOUT,
)
# Set of users who have presence in the `user_to_current_state` that
# have not yet been persisted
self.unpersisted_users_changes: Set[str] = set()
hs.get_reactor().addSystemEventTrigger(
"before",
"shutdown",
run_as_background_process,
"presence.on_shutdown",
self._on_shutdown,
)
# Keeps track of the number of *ongoing* syncs on this process. While
# this is non zero a user will never go offline.
self.user_to_num_current_syncs: Dict[str, int] = {}
# Keeps track of the number of *ongoing* syncs on other processes.
# While any sync is ongoing on another process the user will never
# go offline.
# Each process has a unique identifier and an update frequency. If
# no update is received from that process within the update period then
# we assume that all the sync requests on that process have stopped.
# Stored as a dict from process_id to set of user_id, and a dict of
# process_id to millisecond timestamp last updated.
self.external_process_to_current_syncs: Dict[str, Set[str]] = {}
self.external_process_last_updated_ms: Dict[str, int] = {}
self.external_sync_linearizer = Linearizer(name="external_sync_linearizer")
if self._presence_enabled:
# Start a LoopingCall in 30s that fires every 5s.
# The initial delay is to allow disconnected clients a chance to
# reconnect before we treat them as offline.
self.clock.call_later(
30, self.clock.looping_call, self._handle_timeouts, 5000
)
self.clock.call_later(
60,
self.clock.looping_call,
self._persist_unpersisted_changes,
60 * 1000,
)
LaterGauge(
"synapse_handlers_presence_wheel_timer_size",
"",
[],
lambda: len(self.wheel_timer),
)
# Used to handle sending of presence to newly joined users/servers
if self._presence_enabled:
self.notifier.add_replication_callback(self.notify_new_event)
# Presence is best effort and quickly heals itself, so lets just always
# stream from the current state when we restart.
self._event_pos = self.store.get_room_max_stream_ordering()
self._event_processing = False
async def _on_shutdown(self) -> None:
"""Gets called when shutting down. This lets us persist any updates that
we haven't yet persisted, e.g. updates that only changes some internal
timers. This allows changes to persist across startup without having to
persist every single change.
If this does not run it simply means that some of the timers will fire
earlier than they should when synapse is restarted. This affect of this
is some spurious presence changes that will self-correct.
"""
# If the DB pool has already terminated, don't try updating
if not self.store.db_pool.is_running():
return
logger.info(
"Performing _on_shutdown. Persisting %d unpersisted changes",
len(self.user_to_current_state),
)
if self.unpersisted_users_changes:
await self.store.update_presence(
[
self.user_to_current_state[user_id]
for user_id in self.unpersisted_users_changes
]
)
logger.info("Finished _on_shutdown")
@wrap_as_background_process("persist_presence_changes")
async def _persist_unpersisted_changes(self) -> None:
"""We periodically persist the unpersisted changes, as otherwise they
may stack up and slow down shutdown times.
"""
unpersisted = self.unpersisted_users_changes
self.unpersisted_users_changes = set()
if unpersisted:
logger.info("Persisting %d unpersisted presence updates", len(unpersisted))
await self.store.update_presence(
[self.user_to_current_state[user_id] for user_id in unpersisted]
)
async def _update_states(
self, new_states: Iterable[UserPresenceState], force_notify: bool = False
) -> None:
"""Updates presence of users. Sets the appropriate timeouts. Pokes
the notifier and federation if and only if the changed presence state
should be sent to clients/servers.
Args:
new_states: The new user presence state updates to process.
force_notify: Whether to force notifying clients of this presence state update,
even if it doesn't change the state of a user's presence (e.g online -> online).
This is currently used to bump the max presence stream ID without changing any
user's presence (see PresenceHandler.add_users_to_send_full_presence_to).
"""
if not self._presence_enabled:
# We shouldn't get here if presence is disabled, but we check anyway
# to ensure that we don't a) send out presence federation and b)
# don't add things to the wheel timer that will never be handled.
logger.warning("Tried to update presence states when presence is disabled")
return
now = self.clock.time_msec()
with Measure(self.clock, "presence_update_states"):
# NOTE: We purposefully don't await between now and when we've
# calculated what we want to do with the new states, to avoid races.
to_notify = {} # Changes we want to notify everyone about
to_federation_ping = {} # These need sending keep-alives
# Only bother handling the last presence change for each user
new_states_dict = {}
for new_state in new_states:
new_states_dict[new_state.user_id] = new_state
new_states = new_states_dict.values()
for new_state in new_states:
user_id = new_state.user_id
# Its fine to not hit the database here, as the only thing not in
# the current state cache are OFFLINE states, where the only field
# of interest is last_active which is safe enough to assume is 0
# here.
prev_state = self.user_to_current_state.get(
user_id, UserPresenceState.default(user_id)
)
new_state, should_notify, should_ping = handle_update(
prev_state,
new_state,
is_mine=self.is_mine_id(user_id),
wheel_timer=self.wheel_timer,
now=now,
)
if force_notify:
should_notify = True
self.user_to_current_state[user_id] = new_state
if should_notify:
to_notify[user_id] = new_state
elif should_ping:
to_federation_ping[user_id] = new_state
# TODO: We should probably ensure there are no races hereafter
presence_updates_counter.inc(len(new_states))
if to_notify:
notified_presence_counter.inc(len(to_notify))
await self._persist_and_notify(list(to_notify.values()))
self.unpersisted_users_changes |= {s.user_id for s in new_states}
self.unpersisted_users_changes -= set(to_notify.keys())
# Check if we need to resend any presence states to remote hosts. We
# only do this for states that haven't been updated in a while to
# ensure that the remote host doesn't time the presence state out.
#
# Note that since these are states that have *not* been updated,
# they won't get sent down the normal presence replication stream,
# and so we have to explicitly send them via the federation stream.
to_federation_ping = {
user_id: state
for user_id, state in to_federation_ping.items()
if user_id not in to_notify
}
if to_federation_ping:
federation_presence_out_counter.inc(len(to_federation_ping))
hosts_to_states = await get_interested_remotes(
self.store,
self.presence_router,
list(to_federation_ping.values()),
)
for destination, states in hosts_to_states.items():
self._federation_queue.send_presence_to_destinations(
states, [destination]
)
@wrap_as_background_process("handle_presence_timeouts")
async def _handle_timeouts(self) -> None:
"""Checks the presence of users that have timed out and updates as
appropriate.
"""
logger.debug("Handling presence timeouts")
now = self.clock.time_msec()
# Fetch the list of users that *may* have timed out. Things may have
# changed since the timeout was set, so we won't necessarily have to
# take any action.
users_to_check = set(self.wheel_timer.fetch(now))
# Check whether the lists of syncing processes from an external
# process have expired.
expired_process_ids = [
process_id
for process_id, last_update in self.external_process_last_updated_ms.items()
if now - last_update > EXTERNAL_PROCESS_EXPIRY
]
for process_id in expired_process_ids:
# For each expired process drop tracking info and check the users
# that were syncing on that process to see if they need to be timed
# out.
users_to_check.update(
self.external_process_to_current_syncs.pop(process_id, ())
)
self.external_process_last_updated_ms.pop(process_id)
states = [
self.user_to_current_state.get(user_id, UserPresenceState.default(user_id))
for user_id in users_to_check
]
timers_fired_counter.inc(len(states))
syncing_user_ids = {
user_id
for user_id, count in self.user_to_num_current_syncs.items()
if count
}
for user_ids in self.external_process_to_current_syncs.values():
syncing_user_ids.update(user_ids)
changes = handle_timeouts(
states,
is_mine_fn=self.is_mine_id,
syncing_user_ids=syncing_user_ids,
now=now,
)
return await self._update_states(changes)
async def bump_presence_active_time(self, user: UserID) -> None:
"""We've seen the user do something that indicates they're interacting
with the app.
"""
# If presence is disabled, no-op
if not self._presence_enabled:
return
user_id = user.to_string()
bump_active_time_counter.inc()
prev_state = await self.current_state_for_user(user_id)
new_fields: Dict[str, Any] = {"last_active_ts": self.clock.time_msec()}
if prev_state.state == PresenceState.UNAVAILABLE:
new_fields["state"] = PresenceState.ONLINE
await self._update_states([prev_state.copy_and_replace(**new_fields)])
async def user_syncing(
self,
user_id: str,
affect_presence: bool = True,
presence_state: str = PresenceState.ONLINE,
) -> ContextManager[None]:
"""Returns a context manager that should surround any stream requests
from the user.
This allows us to keep track of who is currently streaming and who isn't
without having to have timers outside of this module to avoid flickering
when users disconnect/reconnect.
Args:
user_id
affect_presence: If false this function will be a no-op.
Useful for streams that are not associated with an actual
client that is being used by a user.
presence_state: The presence state indicated in the sync request
"""
if not affect_presence or not self._presence_enabled:
return _NullContextManager()
curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
self.user_to_num_current_syncs[user_id] = curr_sync + 1
prev_state = await self.current_state_for_user(user_id)
# If they're busy then they don't stop being busy just by syncing,
# so just update the last sync time.
if prev_state.state != PresenceState.BUSY:
# XXX: We set_state separately here and just update the last_active_ts above
# This keeps the logic as similar as possible between the worker and single
# process modes. Using set_state will actually cause last_active_ts to be
# updated always, which is not what the spec calls for, but synapse has done
# this for... forever, I think.
await self.set_state(
UserID.from_string(user_id),
{"presence": presence_state},
ignore_status_msg=True,
)
# Retrieve the new state for the logic below. This should come from the
# in-memory cache.
prev_state = await self.current_state_for_user(user_id)
# To keep the single process behaviour consistent with worker mode, run the
# same logic as `update_external_syncs_row`, even though it looks weird.
if prev_state.state == PresenceState.OFFLINE:
await self._update_states(
[
prev_state.copy_and_replace(
state=PresenceState.ONLINE,
last_active_ts=self.clock.time_msec(),
last_user_sync_ts=self.clock.time_msec(),
)
]
)
# otherwise, set the new presence state & update the last sync time,
# but don't update last_active_ts as this isn't an indication that
# they've been active (even though it's probably been updated by
# set_state above)
else:
await self._update_states(
[prev_state.copy_and_replace(last_user_sync_ts=self.clock.time_msec())]
)
async def _end() -> None:
try:
self.user_to_num_current_syncs[user_id] -= 1
prev_state = await self.current_state_for_user(user_id)
await self._update_states(
[
prev_state.copy_and_replace(
last_user_sync_ts=self.clock.time_msec()
)
]
)
except Exception:
logger.exception("Error updating presence after sync")
@contextmanager
def _user_syncing() -> Generator[None, None, None]:
try:
yield
finally:
run_in_background(_end)
return _user_syncing()
def get_currently_syncing_users_for_replication(self) -> Iterable[str]:
# since we are the process handling presence, there is nothing to do here.
return []
async def update_external_syncs_row(
self, process_id: str, user_id: str, is_syncing: bool, sync_time_msec: int
) -> None:
"""Update the syncing users for an external process as a delta.
Args:
process_id: An identifier for the process the users are
syncing against. This allows synapse to process updates
as user start and stop syncing against a given process.
user_id: The user who has started or stopped syncing
is_syncing: Whether or not the user is now syncing
sync_time_msec: Time in ms when the user was last syncing
"""
async with self.external_sync_linearizer.queue(process_id):
prev_state = await self.current_state_for_user(user_id)
process_presence = self.external_process_to_current_syncs.setdefault(
process_id, set()
)
updates = []
if is_syncing and user_id not in process_presence:
if prev_state.state == PresenceState.OFFLINE:
updates.append(
prev_state.copy_and_replace(
state=PresenceState.ONLINE,
last_active_ts=sync_time_msec,
last_user_sync_ts=sync_time_msec,
)
)
else:
updates.append(
prev_state.copy_and_replace(last_user_sync_ts=sync_time_msec)
)
process_presence.add(user_id)
elif user_id in process_presence:
updates.append(
prev_state.copy_and_replace(last_user_sync_ts=sync_time_msec)
)
if not is_syncing:
process_presence.discard(user_id)
if updates:
await self._update_states(updates)
self.external_process_last_updated_ms[process_id] = self.clock.time_msec()
async def update_external_syncs_clear(self, process_id: str) -> None:
"""Marks all users that had been marked as syncing by a given process
as offline.
Used when the process has stopped/disappeared.
"""
async with self.external_sync_linearizer.queue(process_id):
process_presence = self.external_process_to_current_syncs.pop(
process_id, set()
)
prev_states = await self.current_state_for_users(process_presence)
time_now_ms = self.clock.time_msec()
await self._update_states(
[
prev_state.copy_and_replace(last_user_sync_ts=time_now_ms)
for prev_state in prev_states.values()
]
)
self.external_process_last_updated_ms.pop(process_id, None)
async def _persist_and_notify(self, states: List[UserPresenceState]) -> None:
"""Persist states in the database, poke the notifier and send to
interested remote servers
"""
stream_id, max_token = await self.store.update_presence(states)
parties = await get_interested_parties(self.store, self.presence_router, states)
room_ids_to_states, users_to_states = parties
self.notifier.on_new_event(
StreamKeyType.PRESENCE,
stream_id,
rooms=room_ids_to_states.keys(),
users=[UserID.from_string(u) for u in users_to_states],
)
# We only want to poke the local federation sender, if any, as other
# workers will receive the presence updates via the presence replication
# stream (which is updated by `store.update_presence`).
await self.maybe_send_presence_to_interested_destinations(states)
async def incoming_presence(self, origin: str, content: JsonDict) -> None:
"""Called when we receive a `m.presence` EDU from a remote server."""
if not self._presence_enabled:
return
now = self.clock.time_msec()
updates = []
for push in content.get("push", []):
# A "push" contains a list of presence that we are probably interested
# in.
user_id = push.get("user_id", None)
if not user_id:
logger.info(
"Got presence update from %r with no 'user_id': %r", origin, push
)
continue
if get_domain_from_id(user_id) != origin:
logger.info(
"Got presence update from %r with bad 'user_id': %r",
origin,
user_id,
)
continue
presence_state = push.get("presence", None)
if not presence_state:
logger.info(
"Got presence update from %r with no 'presence_state': %r",
origin,
push,
)
continue
new_fields = {"state": presence_state, "last_federation_update_ts": now}
last_active_ago = push.get("last_active_ago", None)
if last_active_ago is not None:
new_fields["last_active_ts"] = now - last_active_ago
new_fields["status_msg"] = push.get("status_msg", None)
new_fields["currently_active"] = push.get("currently_active", False)
prev_state = await self.current_state_for_user(user_id)
updates.append(prev_state.copy_and_replace(**new_fields))
if updates:
federation_presence_counter.inc(len(updates))
await self._update_states(updates)
async def set_state(
self,
target_user: UserID,
state: JsonDict,
ignore_status_msg: bool = False,
force_notify: bool = False,
) -> None:
"""Set the presence state of the user.
Args:
target_user: The ID of the user to set the presence state of.
state: The presence state as a JSON dictionary.
ignore_status_msg: True to ignore the "status_msg" field of the `state` dict.
If False, the user's current status will be updated.
force_notify: Whether to force notification of the update to clients.
"""
status_msg = state.get("status_msg", None)
presence = state["presence"]
if presence not in self.VALID_PRESENCE:
raise SynapseError(400, "Invalid presence state")
# If presence is disabled, no-op
if not self._presence_enabled:
return
user_id = target_user.to_string()
prev_state = await self.current_state_for_user(user_id)
new_fields = {"state": presence}
if not ignore_status_msg:
new_fields["status_msg"] = status_msg
if presence == PresenceState.ONLINE or (
presence == PresenceState.BUSY and self._busy_presence_enabled
):
new_fields["last_active_ts"] = self.clock.time_msec()
await self._update_states(
[prev_state.copy_and_replace(**new_fields)], force_notify=force_notify
)
async def is_visible(self, observed_user: UserID, observer_user: UserID) -> bool:
"""Returns whether a user can see another user's presence."""
observer_room_ids = await self.store.get_rooms_for_user(
observer_user.to_string()
)
observed_room_ids = await self.store.get_rooms_for_user(
observed_user.to_string()
)
if observer_room_ids & observed_room_ids:
return True
return False
async def get_all_presence_updates(
self, instance_name: str, last_id: int, current_id: int, limit: int
) -> Tuple[List[Tuple[int, list]], int, bool]:
"""
Gets a list of presence update rows from between the given stream ids.
Each row has:
- stream_id(str)
- user_id(str)
- state(str)
- last_active_ts(int)
- last_federation_update_ts(int)
- last_user_sync_ts(int)
- status_msg(int)
- currently_active(int)
Args:
instance_name: The writer we want to fetch updates from. Unused
here since there is only ever one writer.
last_id: The token to fetch updates from. Exclusive.
current_id: The token to fetch updates up to. Inclusive.
limit: The requested limit for the number of rows to return. The
function may return more or fewer rows.
Returns:
A tuple consisting of: the updates, a token to use to fetch
subsequent updates, and whether we returned fewer rows than exists
between the requested tokens due to the limit.
The token returned can be used in a subsequent call to this
function to get further updates.
The updates are a list of 2-tuples of stream ID and the row data
"""
# TODO(markjh): replicate the unpersisted changes.
# This could use the in-memory stores for recent changes.
rows = await self.store.get_all_presence_updates(
instance_name, last_id, current_id, limit
)
return rows
def notify_new_event(self) -> None:
"""Called when new events have happened. Handles users and servers
joining rooms and require being sent presence.
"""
if self._event_processing:
return
async def _process_presence() -> None:
assert not self._event_processing
self._event_processing = True
try:
await self._unsafe_process()
finally:
self._event_processing = False
run_as_background_process("presence.notify_new_event", _process_presence)
async def _unsafe_process(self) -> None:
# Loop round handling deltas until we're up to date
while True:
with Measure(self.clock, "presence_delta"):
room_max_stream_ordering = self.store.get_room_max_stream_ordering()
if self._event_pos == room_max_stream_ordering:
return
logger.debug(
"Processing presence stats %s->%s",
self._event_pos,
room_max_stream_ordering,
)
(
max_pos,
deltas,
) = await self._storage_controllers.state.get_current_state_deltas(
self._event_pos, room_max_stream_ordering
)
# We may get multiple deltas for different rooms, but we want to
# handle them on a room by room basis, so we batch them up by
# room.
deltas_by_room: Dict[str, List[JsonDict]] = {}
for delta in deltas:
deltas_by_room.setdefault(delta["room_id"], []).append(delta)
for room_id, deltas_for_room in deltas_by_room.items():
await self._handle_state_delta(room_id, deltas_for_room)
self._event_pos = max_pos
# Expose current event processing position to prometheus
synapse.metrics.event_processing_positions.labels("presence").set(
max_pos
)
async def _handle_state_delta(self, room_id: str, deltas: List[JsonDict]) -> None:
"""Process current state deltas for the room to find new joins that need
to be handled.
"""
# Sets of newly joined users. Note that if the local server is
# joining a remote room for the first time we'll see both the joining
# user and all remote users as newly joined.
newly_joined_users = set()
for delta in deltas:
assert room_id == delta["room_id"]
typ = delta["type"]
state_key = delta["state_key"]
event_id = delta["event_id"]
prev_event_id = delta["prev_event_id"]
logger.debug("Handling: %r %r, %s", typ, state_key, event_id)
# Drop any event that isn't a membership join
if typ != EventTypes.Member:
continue
if event_id is None:
# state has been deleted, so this is not a join. We only care about
# joins.
continue
event = await self.store.get_event(event_id, allow_none=True)
if not event or event.content.get("membership") != Membership.JOIN:
# We only care about joins
continue
if prev_event_id:
prev_event = await self.store.get_event(prev_event_id, allow_none=True)
if (
prev_event
and prev_event.content.get("membership") == Membership.JOIN
):
# Ignore changes to join events.
continue
newly_joined_users.add(state_key)
if not newly_joined_users:
# If nobody has joined then there's nothing to do.
return
# We want to send:
# 1. presence states of all local users in the room to newly joined
# remote servers
# 2. presence states of newly joined users to all remote servers in
# the room.
#
# TODO: Only send presence states to remote hosts that don't already
# have them (because they already share rooms).
# Get all the users who were already in the room, by fetching the
# current users in the room and removing the newly joined users.
users = await self.store.get_users_in_room(room_id)
prev_users = set(users) - newly_joined_users
# Construct sets for all the local users and remote hosts that were
# already in the room
prev_local_users = []
prev_remote_hosts = set()
for user_id in prev_users:
if self.is_mine_id(user_id):
prev_local_users.append(user_id)
else:
prev_remote_hosts.add(get_domain_from_id(user_id))
# Similarly, construct sets for all the local users and remote hosts
# that were *not* already in the room. Care needs to be taken with the
# calculating the remote hosts, as a host may have already been in the
# room even if there is a newly joined user from that host.
newly_joined_local_users = []
newly_joined_remote_hosts = set()
for user_id in newly_joined_users:
if self.is_mine_id(user_id):
newly_joined_local_users.append(user_id)
else:
host = get_domain_from_id(user_id)
if host not in prev_remote_hosts:
newly_joined_remote_hosts.add(host)
# Send presence states of all local users in the room to newly joined
# remote servers. (We actually only send states for local users already
# in the room, as we'll send states for newly joined local users below.)
if prev_local_users and newly_joined_remote_hosts:
local_states = await self.current_state_for_users(prev_local_users)
# Filter out old presence, i.e. offline presence states where
# the user hasn't been active for a week. We can change this
# depending on what we want the UX to be, but at the least we
# should filter out offline presence where the state is just the
# default state.
now = self.clock.time_msec()
states = [
state
for state in local_states.values()
if state.state != PresenceState.OFFLINE
or now - state.last_active_ts < 7 * 24 * 60 * 60 * 1000
or state.status_msg is not None
]
self._federation_queue.send_presence_to_destinations(
destinations=newly_joined_remote_hosts,
states=states,
)
# Send presence states of newly joined users to all remote servers in
# the room
if newly_joined_local_users and (
prev_remote_hosts or newly_joined_remote_hosts
):
local_states = await self.current_state_for_users(newly_joined_local_users)
self._federation_queue.send_presence_to_destinations(
destinations=prev_remote_hosts | newly_joined_remote_hosts,
states=list(local_states.values()),
)
def should_notify(
old_state: UserPresenceState, new_state: UserPresenceState, is_mine: bool
) -> bool:
"""Decides if a presence state change should be sent to interested parties."""
user_location = "remote"
if is_mine:
user_location = "local"
if old_state == new_state:
return False
if old_state.status_msg != new_state.status_msg:
notify_reason_counter.labels(user_location, "status_msg_change").inc()
return True
if old_state.state != new_state.state:
notify_reason_counter.labels(user_location, "state_change").inc()
state_transition_counter.labels(
user_location, old_state.state, new_state.state
).inc()
return True
if old_state.state == PresenceState.ONLINE:
if new_state.currently_active != old_state.currently_active:
notify_reason_counter.labels(user_location, "current_active_change").inc()
return True
if (
new_state.last_active_ts - old_state.last_active_ts
> LAST_ACTIVE_GRANULARITY
):
# Only notify about last active bumps if we're not currently active
if not new_state.currently_active:
notify_reason_counter.labels(
user_location, "last_active_change_online"
).inc()
return True
elif new_state.last_active_ts - old_state.last_active_ts > LAST_ACTIVE_GRANULARITY:
# Always notify for a transition where last active gets bumped.
notify_reason_counter.labels(
user_location, "last_active_change_not_online"
).inc()
return True
return False
def format_user_presence_state(
state: UserPresenceState, now: int, include_user_id: bool = True
) -> JsonDict:
"""Convert UserPresenceState to a JSON format that can be sent down to clients
and to other servers.
Args:
state: The user presence state to format.
now: The current timestamp since the epoch in ms.
include_user_id: Whether to include `user_id` in the returned dictionary.
As this function can be used both to format presence updates for client /sync
responses and for federation /send requests, only the latter needs the include
the `user_id` field.
Returns:
A JSON dictionary with the following keys:
* presence: The presence state as a str.
* user_id: Optional. Included if `include_user_id` is truthy. The canonical
Matrix ID of the user.
* last_active_ago: Optional. Included if `last_active_ts` is set on `state`.
The timestamp that the user was last active.
* status_msg: Optional. Included if `status_msg` is set on `state`. The user's
status.
* currently_active: Optional. Included only if `state.state` is "online".
Example:
{
"presence": "online",
"user_id": "@alice:example.com",
"last_active_ago": 16783813918,
"status_msg": "Hello world!",
"currently_active": True
}
"""
content: JsonDict = {"presence": state.state}
if include_user_id:
content["user_id"] = state.user_id
if state.last_active_ts:
content["last_active_ago"] = now - state.last_active_ts
if state.status_msg:
content["status_msg"] = state.status_msg
if state.state == PresenceState.ONLINE:
content["currently_active"] = state.currently_active
return content
class PresenceEventSource(EventSource[int, UserPresenceState]):
def __init__(self, hs: "HomeServer"):
# We can't call get_presence_handler here because there's a cycle:
#
# Presence -> Notifier -> PresenceEventSource -> Presence
#
# Same with get_presence_router:
#
# AuthHandler -> Notifier -> PresenceEventSource -> ModuleApi -> AuthHandler
self.get_presence_handler = hs.get_presence_handler
self.get_presence_router = hs.get_presence_router
self.clock = hs.get_clock()
self.store = hs.get_datastores().main
async def get_new_events(
self,
user: UserID,
from_key: Optional[int],
# Having a default limit doesn't match the EventSource API, but some
# callers do not provide it. It is unused in this class.
limit: int = 0,
room_ids: Optional[StrCollection] = None,
is_guest: bool = False,
explicit_room_id: Optional[str] = None,
include_offline: bool = True,
service: Optional[ApplicationService] = None,
) -> Tuple[List[UserPresenceState], int]:
# The process for getting presence events are:
# 1. Get the rooms the user is in.
# 2. Get the list of user in the rooms.
# 3. Get the list of users that are in the user's presence list.
# 4. If there is a from_key set, cross reference the list of users
# with the `presence_stream_cache` to see which ones we actually
# need to check.
# 5. Load current state for the users.
#
# We don't try and limit the presence updates by the current token, as
# sending down the rare duplicate is not a concern.
user_id = user.to_string()
stream_change_cache = self.store.presence_stream_cache
with Measure(self.clock, "presence.get_new_events"):
if from_key is not None:
from_key = int(from_key)
# Check if this user should receive all current, online user presence. We only
# bother to do this if from_key is set, as otherwise the user will receive all
# user presence anyways.
if await self.store.should_user_receive_full_presence_with_token(
user_id, from_key
):
# This user has been specified by a module to receive all current, online
# user presence. Removing from_key and setting include_offline to false
# will do effectively this.
from_key = None
include_offline = False
max_token = self.store.get_current_presence_token()
if from_key == max_token:
# This is necessary as due to the way stream ID generators work
# we may get updates that have a stream ID greater than the max
# token (e.g. max_token is N but stream generator may return
# results for N+2, due to N+1 not having finished being
# persisted yet).
#
# This is usually fine, as it just means that we may send down
# some presence updates multiple times. However, we need to be
# careful that the sync stream either actually does make some
# progress or doesn't return, otherwise clients will end up
# tight looping calling /sync due to it immediately returning
# the same token repeatedly.
#
# Hence this guard where we just return nothing so that the sync
# doesn't return. C.f. #5503.
return [], max_token
# Figure out which other users this user should explicitly receive
# updates for
additional_users_interested_in = (
await self.get_presence_router().get_interested_users(user.to_string())
)
# We have a set of users that we're interested in the presence of. We want to
# cross-reference that with the users that have actually changed their presence.
# Check whether this user should see all user updates
if additional_users_interested_in == PresenceRouter.ALL_USERS:
# Provide presence state for all users
presence_updates = await self._filter_all_presence_updates_for_user(
user_id, include_offline, from_key
)
return presence_updates, max_token
# Make mypy happy. users_interested_in should now be a set
assert not isinstance(additional_users_interested_in, str)
# We always care about our own presence.
additional_users_interested_in.add(user_id)
if explicit_room_id:
user_ids = await self.store.get_users_in_room(explicit_room_id)
additional_users_interested_in.update(user_ids)
# The set of users that we're interested in and that have had a presence update.
# We'll actually pull the presence updates for these users at the end.
interested_and_updated_users: StrCollection
if from_key is not None:
# First get all users that have had a presence update
result = stream_change_cache.get_all_entities_changed(from_key)
# Cross-reference users we're interested in with those that have had updates.
if result.hit:
updated_users = result.entities
# If we have the full list of changes for presence we can
# simply check which ones share a room with the user.
get_updates_counter.labels("stream").inc()
sharing_users = await self.store.do_users_share_a_room(
user_id, updated_users
)
interested_and_updated_users = (
sharing_users.union(additional_users_interested_in)
).intersection(updated_users)
else:
# Too many possible updates. Find all users we can see and check
# if any of them have changed.
get_updates_counter.labels("full").inc()
users_interested_in = (
await self.store.get_users_who_share_room_with_user(user_id)
)
users_interested_in.update(additional_users_interested_in)
interested_and_updated_users = (
stream_change_cache.get_entities_changed(
users_interested_in, from_key
)
)
else:
# No from_key has been specified. Return the presence for all users
# this user is interested in
interested_and_updated_users = (
await self.store.get_users_who_share_room_with_user(user_id)
)
interested_and_updated_users.update(additional_users_interested_in)
# Retrieve the current presence state for each user
users_to_state = await self.get_presence_handler().current_state_for_users(
interested_and_updated_users
)
presence_updates = list(users_to_state.values())
if not include_offline:
# Filter out offline presence states
presence_updates = self._filter_offline_presence_state(presence_updates)
return presence_updates, max_token
async def _filter_all_presence_updates_for_user(
self,
user_id: str,
include_offline: bool,
from_key: Optional[int] = None,
) -> List[UserPresenceState]:
"""
Computes the presence updates a user should receive.
First pulls presence updates from the database. Then consults PresenceRouter
for whether any updates should be excluded by user ID.
Args:
user_id: The User ID of the user to compute presence updates for.
include_offline: Whether to include offline presence states from the results.
from_key: The minimum stream ID of updates to pull from the database
before filtering.
Returns:
A list of presence states for the given user to receive.
"""
updated_users = None
if from_key:
# Only return updates since the last sync
result = self.store.presence_stream_cache.get_all_entities_changed(from_key)
if result.hit:
updated_users = result.entities
if updated_users is not None:
# Get the actual presence update for each change
users_to_state = await self.get_presence_handler().current_state_for_users(
updated_users
)
presence_updates = list(users_to_state.values())
if not include_offline:
# Filter out offline states
presence_updates = self._filter_offline_presence_state(presence_updates)
else:
users_to_state = await self.store.get_presence_for_all_users(
include_offline=include_offline
)
presence_updates = list(users_to_state.values())
# TODO: This feels wildly inefficient, and it's unfortunate we need to ask the
# module for information on a number of users when we then only take the info
# for a single user
# Filter through the presence router
users_to_state_set = await self.get_presence_router().get_users_for_states(
presence_updates
)
# We only want the mapping for the syncing user
presence_updates = list(users_to_state_set[user_id])
# Return presence information for all users
return presence_updates
def _filter_offline_presence_state(
self, presence_updates: Iterable[UserPresenceState]
) -> List[UserPresenceState]:
"""Given an iterable containing user presence updates, return a list with any offline
presence states removed.
Args:
presence_updates: Presence states to filter
Returns:
A new list with any offline presence states removed.
"""
return [
update
for update in presence_updates
if update.state != PresenceState.OFFLINE
]
def get_current_key(self) -> int:
return self.store.get_current_presence_token()
def handle_timeouts(
user_states: List[UserPresenceState],
is_mine_fn: Callable[[str], bool],
syncing_user_ids: Set[str],
now: int,
) -> List[UserPresenceState]:
"""Checks the presence of users that have timed out and updates as
appropriate.
Args:
user_states: List of UserPresenceState's to check.
is_mine_fn: Function that returns if a user_id is ours
syncing_user_ids: Set of user_ids with active syncs.
now: Current time in ms.
Returns:
List of UserPresenceState updates
"""
changes = {} # Actual changes we need to notify people about
for state in user_states:
is_mine = is_mine_fn(state.user_id)
new_state = handle_timeout(state, is_mine, syncing_user_ids, now)
if new_state:
changes[state.user_id] = new_state
return list(changes.values())
def handle_timeout(
state: UserPresenceState, is_mine: bool, syncing_user_ids: Set[str], now: int
) -> Optional[UserPresenceState]:
"""Checks the presence of the user to see if any of the timers have elapsed
Args:
state
is_mine: Whether the user is ours
syncing_user_ids: Set of user_ids with active syncs.
now: Current time in ms.
Returns:
A UserPresenceState update or None if no update.
"""
if state.state == PresenceState.OFFLINE:
# No timeouts are associated with offline states.
return None
changed = False
user_id = state.user_id
if is_mine:
if state.state == PresenceState.ONLINE:
if now - state.last_active_ts > IDLE_TIMER:
# Currently online, but last activity ages ago so auto
# idle
state = state.copy_and_replace(state=PresenceState.UNAVAILABLE)
changed = True
elif now - state.last_active_ts > LAST_ACTIVE_GRANULARITY:
# So that we send down a notification that we've
# stopped updating.
changed = True
if now - state.last_federation_update_ts > FEDERATION_PING_INTERVAL:
# Need to send ping to other servers to ensure they don't
# timeout and set us to offline
changed = True
# If there are have been no sync for a while (and none ongoing),
# set presence to offline
if user_id not in syncing_user_ids:
# If the user has done something recently but hasn't synced,
# don't set them as offline.
sync_or_active = max(state.last_user_sync_ts, state.last_active_ts)
if now - sync_or_active > SYNC_ONLINE_TIMEOUT:
state = state.copy_and_replace(state=PresenceState.OFFLINE)
changed = True
else:
# We expect to be poked occasionally by the other side.
# This is to protect against forgetful/buggy servers, so that
# no one gets stuck online forever.
if now - state.last_federation_update_ts > FEDERATION_TIMEOUT:
# The other side seems to have disappeared.
state = state.copy_and_replace(state=PresenceState.OFFLINE)
changed = True
return state if changed else None
def handle_update(
prev_state: UserPresenceState,
new_state: UserPresenceState,
is_mine: bool,
wheel_timer: WheelTimer,
now: int,
) -> Tuple[UserPresenceState, bool, bool]:
"""Given a presence update:
1. Add any appropriate timers.
2. Check if we should notify anyone.
Args:
prev_state
new_state
is_mine: Whether the user is ours
wheel_timer
now: Time now in ms
Returns:
3-tuple: `(new_state, persist_and_notify, federation_ping)` where:
- new_state: is the state to actually persist
- persist_and_notify: whether to persist and notify people
- federation_ping: whether we should send a ping over federation
"""
user_id = new_state.user_id
persist_and_notify = False
federation_ping = False
# If the users are ours then we want to set up a bunch of timers
# to time things out.
if is_mine:
if new_state.state == PresenceState.ONLINE:
# Idle timer
wheel_timer.insert(
now=now, obj=user_id, then=new_state.last_active_ts + IDLE_TIMER
)
active = now - new_state.last_active_ts < LAST_ACTIVE_GRANULARITY
new_state = new_state.copy_and_replace(currently_active=active)
if active:
wheel_timer.insert(
now=now,
obj=user_id,
then=new_state.last_active_ts + LAST_ACTIVE_GRANULARITY,
)
if new_state.state != PresenceState.OFFLINE:
# User has stopped syncing
wheel_timer.insert(
now=now,
obj=user_id,
then=new_state.last_user_sync_ts + SYNC_ONLINE_TIMEOUT,
)
last_federate = new_state.last_federation_update_ts
if now - last_federate > FEDERATION_PING_INTERVAL:
# Been a while since we've poked remote servers
new_state = new_state.copy_and_replace(last_federation_update_ts=now)
federation_ping = True
else:
wheel_timer.insert(
now=now,
obj=user_id,
then=new_state.last_federation_update_ts + FEDERATION_TIMEOUT,
)
# Check whether the change was something worth notifying about
if should_notify(prev_state, new_state, is_mine):
new_state = new_state.copy_and_replace(last_federation_update_ts=now)
persist_and_notify = True
return new_state, persist_and_notify, federation_ping
async def get_interested_parties(
store: DataStore, presence_router: PresenceRouter, states: List[UserPresenceState]
) -> Tuple[Dict[str, List[UserPresenceState]], Dict[str, List[UserPresenceState]]]:
"""Given a list of states return which entities (rooms, users)
are interested in the given states.
Args:
store: The homeserver's data store.
presence_router: A module for augmenting the destinations for presence updates.
states: A list of incoming user presence updates.
Returns:
A 2-tuple of `(room_ids_to_states, users_to_states)`,
with each item being a dict of `entity_name` -> `[UserPresenceState]`
"""
room_ids_to_states: Dict[str, List[UserPresenceState]] = {}
users_to_states: Dict[str, List[UserPresenceState]] = {}
for state in states:
room_ids = await store.get_rooms_for_user(state.user_id)
for room_id in room_ids:
room_ids_to_states.setdefault(room_id, []).append(state)
# Always notify self
users_to_states.setdefault(state.user_id, []).append(state)
# Ask a presence routing module for any additional parties if one
# is loaded.
router_users_to_states = await presence_router.get_users_for_states(states)
# Update the dictionaries with additional destinations and state to send
for user_id, user_states in router_users_to_states.items():
users_to_states.setdefault(user_id, []).extend(user_states)
return room_ids_to_states, users_to_states
async def get_interested_remotes(
store: DataStore,
presence_router: PresenceRouter,
states: List[UserPresenceState],
) -> Dict[str, Set[UserPresenceState]]:
"""Given a list of presence states figure out which remote servers
should be sent which.
All the presence states should be for local users only.
Args:
store: The homeserver's data store.
presence_router: A module for augmenting the destinations for presence updates.
states: A list of incoming user presence updates.
Returns:
A map from destinations to presence states to send to that destination.
"""
hosts_and_states: Dict[str, Set[UserPresenceState]] = {}
# First we look up the rooms each user is in (as well as any explicit
# subscriptions), then for each distinct room we look up the remote
# hosts in those rooms.
room_ids_to_states, users_to_states = await get_interested_parties(
store, presence_router, states
)
for room_id, states in room_ids_to_states.items():
hosts = await store.get_current_hosts_in_room(room_id)
for host in hosts:
hosts_and_states.setdefault(host, set()).update(states)
for user_id, states in users_to_states.items():
host = get_domain_from_id(user_id)
hosts_and_states.setdefault(host, set()).update(states)
return hosts_and_states
class PresenceFederationQueue:
"""Handles sending ad hoc presence updates over federation, which are *not*
due to state updates (that get handled via the presence stream), e.g.
federation pings and sending existing present states to newly joined hosts.
Only the last N minutes will be queued, so if a federation sender instance
is down for longer then some updates will be dropped. This is OK as presence
is ephemeral, and so it will self correct eventually.
On workers the class tracks the last received position of the stream from
replication, and handles querying for missed updates over HTTP replication,
c.f. `get_current_token` and `get_replication_rows`.
"""
# How long to keep entries in the queue for. Workers that are down for
# longer than this duration will miss out on older updates.
_KEEP_ITEMS_IN_QUEUE_FOR_MS = 5 * 60 * 1000
# How often to check if we can expire entries from the queue.
_CLEAR_ITEMS_EVERY_MS = 60 * 1000
def __init__(self, hs: "HomeServer", presence_handler: BasePresenceHandler):
self._clock = hs.get_clock()
self._notifier = hs.get_notifier()
self._instance_name = hs.get_instance_name()
self._presence_handler = presence_handler
self._repl_client = ReplicationGetStreamUpdates.make_client(hs)
# Should we keep a queue of recent presence updates? We only bother if
# another process may be handling federation sending.
self._queue_presence_updates = True
# Whether this instance is a presence writer.
self._presence_writer = self._instance_name in hs.config.worker.writers.presence
# The FederationSender instance, if this process sends federation traffic directly.
self._federation = None
if hs.should_send_federation():
self._federation = hs.get_federation_sender()
# We don't bother queuing up presence states if only this instance
# is sending federation.
if hs.config.worker.federation_shard_config.instances == [
self._instance_name
]:
self._queue_presence_updates = False
# The queue of recently queued updates as tuples of: `(timestamp,
# stream_id, destinations, user_ids)`. We don't store the full states
# for efficiency, and remote workers will already have the full states
# cached.
self._queue: List[Tuple[int, int, StrCollection, Set[str]]] = []
self._next_id = 1
# Map from instance name to current token
self._current_tokens: Dict[str, int] = {}
if self._queue_presence_updates:
self._clock.looping_call(self._clear_queue, self._CLEAR_ITEMS_EVERY_MS)
def _clear_queue(self) -> None:
"""Clear out older entries from the queue."""
clear_before = self._clock.time_msec() - self._KEEP_ITEMS_IN_QUEUE_FOR_MS
# The queue is sorted by timestamp, so we can bisect to find the right
# place to purge before. Note that we are searching using a 1-tuple with
# the time, which does The Right Thing since the queue is a tuple where
# the first item is a timestamp.
index = bisect(self._queue, (clear_before,))
self._queue = self._queue[index:]
def send_presence_to_destinations(
self, states: Collection[UserPresenceState], destinations: StrCollection
) -> None:
"""Send the presence states to the given destinations.
Will forward to the local federation sender (if there is one) and queue
to send over replication (if there are other federation sender instances.).
Must only be called on the presence writer process.
"""
# This should only be called on a presence writer.
assert self._presence_writer
if not states or not destinations:
# Ignore calls which either don't have any new states or don't need
# to be sent anywhere.
return
if self._federation:
self._federation.send_presence_to_destinations(
states=states,
destinations=destinations,
)
if not self._queue_presence_updates:
return
now = self._clock.time_msec()
stream_id = self._next_id
self._next_id += 1
self._queue.append((now, stream_id, destinations, {s.user_id for s in states}))
self._notifier.notify_replication()
def get_current_token(self, instance_name: str) -> int:
"""Get the current position of the stream.
On workers this returns the last stream ID received from replication.
"""
if instance_name == self._instance_name:
return self._next_id - 1
else:
return self._current_tokens.get(instance_name, 0)
async def get_replication_rows(
self,
instance_name: str,
from_token: int,
upto_token: int,
target_row_count: int,
) -> Tuple[List[Tuple[int, Tuple[str, str]]], int, bool]:
"""Get all the updates between the two tokens.
We return rows in the form of `(destination, user_id)` to keep the size
of each row bounded (rather than returning the sets in a row).
On workers this will query the presence writer process via HTTP replication.
"""
if instance_name != self._instance_name:
# If not local we query over http replication from the presence
# writer
result = await self._repl_client(
instance_name=instance_name,
stream_name=PresenceFederationStream.NAME,
from_token=from_token,
upto_token=upto_token,
)
return result["updates"], result["upto_token"], result["limited"]
# If the from_token is the current token then there's nothing to return
# and we can trivially no-op.
if from_token == self._next_id - 1:
return [], upto_token, False
# We can find the correct position in the queue by noting that there is
# exactly one entry per stream ID, and that the last entry has an ID of
# `self._next_id - 1`, so we can count backwards from the end.
#
# Since we are returning all states in the range `from_token < stream_id
# <= upto_token` we look for the index with a `stream_id` of `from_token
# + 1`.
#
# Since the start of the queue is periodically truncated we need to
# handle the case where `from_token` stream ID has already been dropped.
start_idx = max(from_token + 1 - self._next_id, -len(self._queue))
to_send: List[Tuple[int, Tuple[str, str]]] = []
limited = False
new_id = upto_token
for _, stream_id, destinations, user_ids in self._queue[start_idx:]:
if stream_id <= from_token:
# Paranoia check that we are actually only sending states that
# are have stream_id strictly greater than from_token. We should
# never hit this.
logger.warning(
"Tried returning presence federation stream ID: %d less than from_token: %d (next_id: %d, len: %d)",
stream_id,
from_token,
self._next_id,
len(self._queue),
)
continue
if stream_id > upto_token:
break
new_id = stream_id
to_send.extend(
(stream_id, (destination, user_id))
for destination in destinations
for user_id in user_ids
)
if len(to_send) > target_row_count:
limited = True
break
return to_send, new_id, limited
async def process_replication_rows(
self, stream_name: str, instance_name: str, token: int, rows: list
) -> None:
if stream_name != PresenceFederationStream.NAME:
return
# We keep track of the current tokens (so that we can catch up with anything we missed after a disconnect)
self._current_tokens[instance_name] = token
# If we're a federation sender we pull out the presence states to send
# and forward them on.
if not self._federation:
return
hosts_to_users: Dict[str, Set[str]] = {}
for row in rows:
hosts_to_users.setdefault(row.destination, set()).add(row.user_id)
for host, user_ids in hosts_to_users.items():
states = await self._presence_handler.current_state_for_users(user_ids)
self._federation.send_presence_to_destinations(
states=states.values(),
destinations=[host],
)
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