Easy refactors of the user directory (#10789)

No functional changes here. This came out as I was working to tackle #5677
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David Robertson 2021-09-10 10:54:38 +01:00 committed by GitHub
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8 changed files with 90 additions and 37 deletions

1
changelog.d/10789.misc Normal file
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@ -0,0 +1 @@
Improve internal details of the user directory code.

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@ -10,3 +10,40 @@ DB corruption) get stale or out of sync. If this happens, for now the
solution to fix it is to execute the SQL [here](https://github.com/matrix-org/synapse/blob/master/synapse/storage/schema/main/delta/53/user_dir_populate.sql)
and then restart synapse. This should then start a background task to
flush the current tables and regenerate the directory.
Data model
----------
There are five relevant tables that collectively form the "user directory".
Three of them track a master list of all the users we could search for.
The last two (collectively called the "search tables") track who can
see who.
From all of these tables we exclude three types of local user:
- support users
- appservice users
- deactivated users
* `user_directory`. This contains the user_id, display name and avatar we'll
return when you search the directory.
- Because there's only one directory entry per user, it's important that we only
ever put publicly visible names here. Otherwise we might leak a private
nickname or avatar used in a private room.
- Indexed on rooms. Indexed on users.
* `user_directory_search`. To be joined to `user_directory`. It contains an extra
column that enables full text search based on user ids and display names.
Different schemas for SQLite and Postgres with different code paths to match.
- Indexed on the full text search data. Indexed on users.
* `user_directory_stream_pos`. When the initial background update to populate
the directory is complete, we record a stream position here. This indicates
that synapse should now listen for room changes and incrementally update
the directory where necessary.
* `users_in_public_rooms`. Contains associations between users and the public rooms they're in.
Used to determine which users are in public rooms and should be publicly visible in the directory.
* `users_who_share_private_rooms`. Rows are triples `(L, M, room id)` where `L`
is a local user and `M` is a local or remote user. `L` and `M` should be
different, but this isn't enforced by a constraint.

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@ -131,7 +131,7 @@ class DeactivateAccountHandler(BaseHandler):
await self.store.add_user_pending_deactivation(user_id)
# delete from user directory
await self.user_directory_handler.handle_user_deactivated(user_id)
await self.user_directory_handler.handle_local_user_deactivated(user_id)
# Mark the user as erased, if they asked for that
if erase_data:

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@ -13,6 +13,7 @@
# limitations under the License.
import logging
from enum import Enum, auto
from typing import TYPE_CHECKING, Optional
if TYPE_CHECKING:
@ -21,6 +22,12 @@ if TYPE_CHECKING:
logger = logging.getLogger(__name__)
class MatchChange(Enum):
no_change = auto()
now_true = auto()
now_false = auto()
class StateDeltasHandler:
def __init__(self, hs: "HomeServer"):
self.store = hs.get_datastore()
@ -31,18 +38,12 @@ class StateDeltasHandler:
event_id: Optional[str],
key_name: str,
public_value: str,
) -> Optional[bool]:
) -> MatchChange:
"""Given two events check if the `key_name` field in content changed
from not matching `public_value` to doing so.
For example, check if `history_visibility` (`key_name`) changed from
`shared` to `world_readable` (`public_value`).
Returns:
None if the field in the events either both match `public_value`
or if neither do, i.e. there has been no change.
True if it didn't match `public_value` but now does
False if it did match `public_value` but now doesn't
"""
prev_event = None
event = None
@ -54,7 +55,7 @@ class StateDeltasHandler:
if not event and not prev_event:
logger.debug("Neither event exists: %r %r", prev_event_id, event_id)
return None
return MatchChange.no_change
prev_value = None
value = None
@ -68,8 +69,8 @@ class StateDeltasHandler:
logger.debug("prev_value: %r -> value: %r", prev_value, value)
if value == public_value and prev_value != public_value:
return True
return MatchChange.now_true
elif value != public_value and prev_value == public_value:
return False
return MatchChange.now_false
else:
return None
return MatchChange.no_change

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@ -17,7 +17,7 @@ from typing import TYPE_CHECKING, Any, Dict, List, Optional
import synapse.metrics
from synapse.api.constants import EventTypes, HistoryVisibility, JoinRules, Membership
from synapse.handlers.state_deltas import StateDeltasHandler
from synapse.handlers.state_deltas import MatchChange, StateDeltasHandler
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.storage.roommember import ProfileInfo
from synapse.types import JsonDict
@ -30,14 +30,26 @@ logger = logging.getLogger(__name__)
class UserDirectoryHandler(StateDeltasHandler):
"""Handles querying of and keeping updated the user_directory.
"""Handles queries and updates for the user_directory.
N.B.: ASSUMES IT IS THE ONLY THING THAT MODIFIES THE USER DIRECTORY
The user directory is filled with users who this server can see are joined to a
world_readable or publicly joinable room. We keep a database table up to date
by streaming changes of the current state and recalculating whether users should
be in the directory or not when necessary.
When a local user searches the user_directory, we report two kinds of users:
- users this server can see are joined to a world_readable or publicly
joinable room, and
- users belonging to a private room shared by that local user.
The two cases are tracked separately in the `users_in_public_rooms` and
`users_who_share_private_rooms` tables. Both kinds of users have their
username and avatar tracked in a `user_directory` table.
This handler has three responsibilities:
1. Forwarding requests to `/user_directory/search` to the UserDirectoryStore.
2. Providing hooks for the application to call when local users are added,
removed, or have their profile changed.
3. Listening for room state changes that indicate remote users have
joined or left a room, or that their profile has changed.
"""
def __init__(self, hs: "HomeServer"):
@ -130,7 +142,7 @@ class UserDirectoryHandler(StateDeltasHandler):
user_id, profile.display_name, profile.avatar_url
)
async def handle_user_deactivated(self, user_id: str) -> None:
async def handle_local_user_deactivated(self, user_id: str) -> None:
"""Called when a user ID is deactivated"""
# FIXME(#3714): We should probably do this in the same worker as all
# the other changes.
@ -196,7 +208,7 @@ class UserDirectoryHandler(StateDeltasHandler):
public_value=Membership.JOIN,
)
if change is False:
if change is MatchChange.now_false:
# Need to check if the server left the room entirely, if so
# we might need to remove all the users in that room
is_in_room = await self.store.is_host_joined(
@ -219,14 +231,14 @@ class UserDirectoryHandler(StateDeltasHandler):
is_support = await self.store.is_support_user(state_key)
if not is_support:
if change is None:
if change is MatchChange.no_change:
# Handle any profile changes
await self._handle_profile_change(
state_key, room_id, prev_event_id, event_id
)
continue
if change: # The user joined
if change is MatchChange.now_true: # The user joined
event = await self.store.get_event(event_id, allow_none=True)
# It isn't expected for this event to not exist, but we
# don't want the entire background process to break.
@ -263,14 +275,14 @@ class UserDirectoryHandler(StateDeltasHandler):
logger.debug("Handling change for %s: %s", typ, room_id)
if typ == EventTypes.RoomHistoryVisibility:
change = await self._get_key_change(
publicness = await self._get_key_change(
prev_event_id,
event_id,
key_name="history_visibility",
public_value=HistoryVisibility.WORLD_READABLE,
)
elif typ == EventTypes.JoinRules:
change = await self._get_key_change(
publicness = await self._get_key_change(
prev_event_id,
event_id,
key_name="join_rule",
@ -278,9 +290,7 @@ class UserDirectoryHandler(StateDeltasHandler):
)
else:
raise Exception("Invalid event type")
# If change is None, no change. True => become world_readable/public,
# False => was world_readable/public
if change is None:
if publicness is MatchChange.no_change:
logger.debug("No change")
return
@ -290,13 +300,13 @@ class UserDirectoryHandler(StateDeltasHandler):
room_id
)
logger.debug("Change: %r, is_public: %r", change, is_public)
logger.debug("Change: %r, publicness: %r", publicness, is_public)
if change and not is_public:
if publicness is MatchChange.now_true and not is_public:
# If we became world readable but room isn't currently public then
# we ignore the change
return
elif not change and is_public:
elif publicness is MatchChange.now_false and is_public:
# If we stopped being world readable but are still public,
# ignore the change
return

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@ -196,6 +196,11 @@ class RoomMemberWorkerStore(EventsWorkerStore):
) -> Dict[str, ProfileInfo]:
"""Get a mapping from user ID to profile information for all users in a given room.
The profile information comes directly from this room's `m.room.member`
events, and so may be specific to this room rather than part of a user's
global profile. To avoid privacy leaks, the profile data should only be
revealed to users who are already in this room.
Args:
room_id: The ID of the room to retrieve the users of.

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@ -196,7 +196,6 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
)
users_with_profile = await self.get_users_in_room_with_profiles(room_id)
user_ids = set(users_with_profile)
# Update each user in the user directory.
for user_id, profile in users_with_profile.items():
@ -207,7 +206,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
to_insert = set()
if is_public:
for user_id in user_ids:
for user_id in users_with_profile:
if self.get_if_app_services_interested_in_user(user_id):
continue
@ -217,14 +216,14 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
await self.add_users_in_public_rooms(room_id, to_insert)
to_insert.clear()
else:
for user_id in user_ids:
for user_id in users_with_profile:
if not self.hs.is_mine_id(user_id):
continue
if self.get_if_app_services_interested_in_user(user_id):
continue
for other_user_id in user_ids:
for other_user_id in users_with_profile:
if user_id == other_user_id:
continue

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@ -94,7 +94,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
# deactivate user
self.get_success(self.store.set_user_deactivated_status(r_user_id, True))
self.get_success(self.handler.handle_user_deactivated(r_user_id))
self.get_success(self.handler.handle_local_user_deactivated(r_user_id))
# profile is not in directory
profile = self.get_success(self.store.get_user_in_directory(r_user_id))
@ -118,7 +118,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
)
self.store.remove_from_user_dir = Mock(return_value=defer.succeed(None))
self.get_success(self.handler.handle_user_deactivated(s_user_id))
self.get_success(self.handler.handle_local_user_deactivated(s_user_id))
self.store.remove_from_user_dir.not_called()
def test_handle_user_deactivated_regular_user(self):
@ -127,7 +127,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
self.store.register_user(user_id=r_user_id, password_hash=None)
)
self.store.remove_from_user_dir = Mock(return_value=defer.succeed(None))
self.get_success(self.handler.handle_user_deactivated(r_user_id))
self.get_success(self.handler.handle_local_user_deactivated(r_user_id))
self.store.remove_from_user_dir.called_once_with(r_user_id)
def test_private_room(self):