diff --git a/changelog.d/9653.feature b/changelog.d/9653.feature
new file mode 100644
index 0000000000..2f7ccedcfb
--- /dev/null
+++ b/changelog.d/9653.feature
@@ -0,0 +1 @@
+Add initial experimental support for a "space summary" API.
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 3b2f51baab..afdb5bf2fa 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -27,11 +27,13 @@ from typing import (
List,
Mapping,
Optional,
+ Sequence,
Tuple,
TypeVar,
Union,
)
+import attr
from prometheus_client import Counter
from twisted.internet import defer
@@ -455,6 +457,7 @@ class FederationClient(FederationBase):
description: str,
destinations: Iterable[str],
callback: Callable[[str], Awaitable[T]],
+ failover_on_unknown_endpoint: bool = False,
) -> T:
"""Try an operation on a series of servers, until it succeeds
@@ -474,6 +477,10 @@ class FederationClient(FederationBase):
next server tried. Normally the stacktrace is logged but this is
suppressed if the exception is an InvalidResponseError.
+ failover_on_unknown_endpoint: if True, we will try other servers if it looks
+ like a server doesn't support the endpoint. This is typically useful
+ if the endpoint in question is new or experimental.
+
Returns:
The result of callback, if it succeeds
@@ -493,16 +500,31 @@ class FederationClient(FederationBase):
except UnsupportedRoomVersionError:
raise
except HttpResponseException as e:
- if not 500 <= e.code < 600:
- raise e.to_synapse_error()
- else:
- logger.warning(
- "Failed to %s via %s: %i %s",
- description,
- destination,
- e.code,
- e.args[0],
- )
+ synapse_error = e.to_synapse_error()
+ failover = False
+
+ if 500 <= e.code < 600:
+ failover = True
+
+ elif failover_on_unknown_endpoint:
+ # there is no good way to detect an "unknown" endpoint. Dendrite
+ # returns a 404 (with no body); synapse returns a 400
+ # with M_UNRECOGNISED.
+ if e.code == 404 or (
+ e.code == 400 and synapse_error.errcode == Codes.UNRECOGNIZED
+ ):
+ failover = True
+
+ if not failover:
+ raise synapse_error from e
+
+ logger.warning(
+ "Failed to %s via %s: %i %s",
+ description,
+ destination,
+ e.code,
+ e.args[0],
+ )
except Exception:
logger.warning(
"Failed to %s via %s", description, destination, exc_info=True
@@ -1042,3 +1064,141 @@ class FederationClient(FederationBase):
# If we don't manage to find it, return None. It's not an error if a
# server doesn't give it to us.
return None
+
+ async def get_space_summary(
+ self,
+ destinations: Iterable[str],
+ room_id: str,
+ suggested_only: bool,
+ max_rooms_per_space: Optional[int],
+ exclude_rooms: List[str],
+ ) -> "FederationSpaceSummaryResult":
+ """
+ Call other servers to get a summary of the given space
+
+
+ Args:
+ destinations: The remote servers. We will try them in turn, omitting any
+ that have been blacklisted.
+
+ room_id: ID of the space to be queried
+
+ suggested_only: If true, ask the remote server to only return children
+ with the "suggested" flag set
+
+ max_rooms_per_space: A limit on the number of children to return for each
+ space
+
+ exclude_rooms: A list of room IDs to tell the remote server to skip
+
+ Returns:
+ a parsed FederationSpaceSummaryResult
+
+ Raises:
+ SynapseError if we were unable to get a valid summary from any of the
+ remote servers
+ """
+
+ async def send_request(destination: str) -> FederationSpaceSummaryResult:
+ res = await self.transport_layer.get_space_summary(
+ destination=destination,
+ room_id=room_id,
+ suggested_only=suggested_only,
+ max_rooms_per_space=max_rooms_per_space,
+ exclude_rooms=exclude_rooms,
+ )
+
+ try:
+ return FederationSpaceSummaryResult.from_json_dict(res)
+ except ValueError as e:
+ raise InvalidResponseError(str(e))
+
+ return await self._try_destination_list(
+ "fetch space summary",
+ destinations,
+ send_request,
+ failover_on_unknown_endpoint=True,
+ )
+
+
+@attr.s(frozen=True, slots=True)
+class FederationSpaceSummaryEventResult:
+ """Represents a single event in the result of a successful get_space_summary call.
+
+ It's essentially just a serialised event object, but we do a bit of parsing and
+ validation in `from_json_dict` and store some of the validated properties in
+ object attributes.
+ """
+
+ event_type = attr.ib(type=str)
+ state_key = attr.ib(type=str)
+ via = attr.ib(type=Sequence[str])
+
+ # the raw data, including the above keys
+ data = attr.ib(type=JsonDict)
+
+ @classmethod
+ def from_json_dict(cls, d: JsonDict) -> "FederationSpaceSummaryEventResult":
+ """Parse an event within the result of a /spaces/ request
+
+ Args:
+ d: json object to be parsed
+
+ Raises:
+ ValueError if d is not a valid event
+ """
+
+ event_type = d.get("type")
+ if not isinstance(event_type, str):
+ raise ValueError("Invalid event: 'event_type' must be a str")
+
+ state_key = d.get("state_key")
+ if not isinstance(state_key, str):
+ raise ValueError("Invalid event: 'state_key' must be a str")
+
+ content = d.get("content")
+ if not isinstance(content, dict):
+ raise ValueError("Invalid event: 'content' must be a dict")
+
+ via = content.get("via")
+ if not isinstance(via, Sequence):
+ raise ValueError("Invalid event: 'via' must be a list")
+ if any(not isinstance(v, str) for v in via):
+ raise ValueError("Invalid event: 'via' must be a list of strings")
+
+ return cls(event_type, state_key, via, d)
+
+
+@attr.s(frozen=True, slots=True)
+class FederationSpaceSummaryResult:
+ """Represents the data returned by a successful get_space_summary call."""
+
+ rooms = attr.ib(type=Sequence[JsonDict])
+ events = attr.ib(type=Sequence[FederationSpaceSummaryEventResult])
+
+ @classmethod
+ def from_json_dict(cls, d: JsonDict) -> "FederationSpaceSummaryResult":
+ """Parse the result of a /spaces/ request
+
+ Args:
+ d: json object to be parsed
+
+ Raises:
+ ValueError if d is not a valid /spaces/ response
+ """
+ rooms = d.get("rooms")
+ if not isinstance(rooms, Sequence):
+ raise ValueError("'rooms' must be a list")
+ if any(not isinstance(r, dict) for r in rooms):
+ raise ValueError("Invalid room in 'rooms' list")
+
+ events = d.get("events")
+ if not isinstance(events, Sequence):
+ raise ValueError("'events' must be a list")
+ if any(not isinstance(e, dict) for e in events):
+ raise ValueError("Invalid event in 'events' list")
+ parsed_events = [
+ FederationSpaceSummaryEventResult.from_json_dict(e) for e in events
+ ]
+
+ return cls(rooms, parsed_events)
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 10c4747f97..6aee47c431 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -16,7 +16,7 @@
import logging
import urllib
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
from synapse.api.constants import Membership
from synapse.api.errors import Codes, HttpResponseException, SynapseError
@@ -26,6 +26,7 @@ from synapse.api.urls import (
FEDERATION_V2_PREFIX,
)
from synapse.logging.utils import log_function
+from synapse.types import JsonDict
logger = logging.getLogger(__name__)
@@ -978,6 +979,38 @@ class TransportLayerClient:
return self.client.get_json(destination=destination, path=path)
+ async def get_space_summary(
+ self,
+ destination: str,
+ room_id: str,
+ suggested_only: bool,
+ max_rooms_per_space: Optional[int],
+ exclude_rooms: List[str],
+ ) -> JsonDict:
+ """
+ Args:
+ destination: The remote server
+ room_id: The room ID to ask about.
+ suggested_only: if True, only suggested rooms will be returned
+ max_rooms_per_space: an optional limit to the number of children to be
+ returned per space
+ exclude_rooms: a list of any rooms we can skip
+ """
+ path = _create_path(
+ FEDERATION_UNSTABLE_PREFIX, "/org.matrix.msc2946/spaces/%s", room_id
+ )
+
+ params = {
+ "suggested_only": suggested_only,
+ "exclude_rooms": exclude_rooms,
+ }
+ if max_rooms_per_space is not None:
+ params["max_rooms_per_space"] = max_rooms_per_space
+
+ return await self.client.post_json(
+ destination=destination, path=path, data=params
+ )
+
def _create_path(federation_prefix, path, *args):
"""
diff --git a/synapse/handlers/space_summary.py b/synapse/handlers/space_summary.py
index f5ead9447f..5d9418969d 100644
--- a/synapse/handlers/space_summary.py
+++ b/synapse/handlers/space_summary.py
@@ -16,7 +16,7 @@
import itertools
import logging
from collections import deque
-from typing import TYPE_CHECKING, Iterable, List, Optional, Sequence, Set, Tuple
+from typing import TYPE_CHECKING, Iterable, List, Optional, Sequence, Set, Tuple, cast
import attr
@@ -38,6 +38,9 @@ MAX_ROOMS = 50
# max number of events to return per room.
MAX_ROOMS_PER_SPACE = 50
+# max number of federation servers to hit per room
+MAX_SERVERS_PER_SPACE = 3
+
class SpaceSummaryHandler:
def __init__(self, hs: "HomeServer"):
@@ -47,6 +50,8 @@ class SpaceSummaryHandler:
self._state_handler = hs.get_state_handler()
self._store = hs.get_datastore()
self._event_serializer = hs.get_event_client_serializer()
+ self._server_name = hs.hostname
+ self._federation_client = hs.get_federation_client()
async def get_space_summary(
self,
@@ -78,35 +83,81 @@ class SpaceSummaryHandler:
await self._auth.check_user_in_room_or_world_readable(room_id, requester)
# the queue of rooms to process
- room_queue = deque((_RoomQueueEntry(room_id),))
+ room_queue = deque((_RoomQueueEntry(room_id, ()),))
+ # rooms we have already processed
processed_rooms = set() # type: Set[str]
+ # events we have already processed. We don't necessarily have their event ids,
+ # so instead we key on (room id, state key)
+ processed_events = set() # type: Set[Tuple[str, str]]
+
rooms_result = [] # type: List[JsonDict]
events_result = [] # type: List[JsonDict]
while room_queue and len(rooms_result) < MAX_ROOMS:
queue_entry = room_queue.popleft()
room_id = queue_entry.room_id
+ if room_id in processed_rooms:
+ # already done this room
+ continue
+
logger.debug("Processing room %s", room_id)
- processed_rooms.add(room_id)
+
+ is_in_room = await self._store.is_host_joined(room_id, self._server_name)
# The client-specified max_rooms_per_space limit doesn't apply to the
# room_id specified in the request, so we ignore it if this is the
# first room we are processing.
max_children = max_rooms_per_space if processed_rooms else None
- rooms, events = await self._summarize_local_room(
- requester, room_id, suggested_only, max_children
+ if is_in_room:
+ rooms, events = await self._summarize_local_room(
+ requester, room_id, suggested_only, max_children
+ )
+ else:
+ rooms, events = await self._summarize_remote_room(
+ queue_entry,
+ suggested_only,
+ max_children,
+ exclude_rooms=processed_rooms,
+ )
+
+ logger.debug(
+ "Query of %s returned rooms %s, events %s",
+ queue_entry.room_id,
+ [room.get("room_id") for room in rooms],
+ ["%s->%s" % (ev["room_id"], ev["state_key"]) for ev in events],
)
rooms_result.extend(rooms)
- events_result.extend(events)
- # add any children that we haven't already processed to the queue
- for edge_event in events:
- if edge_event["state_key"] not in processed_rooms:
- room_queue.append(_RoomQueueEntry(edge_event["state_key"]))
+ # any rooms returned don't need visiting again
+ processed_rooms.update(cast(str, room.get("room_id")) for room in rooms)
+
+ # the room we queried may or may not have been returned, but don't process
+ # it again, anyway.
+ processed_rooms.add(room_id)
+
+ # XXX: is it ok that we blindly iterate through any events returned by
+ # a remote server, whether or not they actually link to any rooms in our
+ # tree?
+ for ev in events:
+ # remote servers might return events we have already processed
+ # (eg, Dendrite returns inward pointers as well as outward ones), so
+ # we need to filter them out, to avoid returning duplicate links to the
+ # client.
+ ev_key = (ev["room_id"], ev["state_key"])
+ if ev_key in processed_events:
+ continue
+ events_result.append(ev)
+
+ # add the child to the queue. we have already validated
+ # that the vias are a list of server names.
+ room_queue.append(
+ _RoomQueueEntry(ev["state_key"], ev["content"]["via"])
+ )
+ processed_events.add(ev_key)
return {"rooms": rooms_result, "events": events_result}
@@ -149,20 +200,23 @@ class SpaceSummaryHandler:
while room_queue and len(rooms_result) < MAX_ROOMS:
room_id = room_queue.popleft()
+ if room_id in processed_rooms:
+ # already done this room
+ continue
+
logger.debug("Processing room %s", room_id)
- processed_rooms.add(room_id)
rooms, events = await self._summarize_local_room(
None, room_id, suggested_only, max_rooms_per_space
)
+ processed_rooms.add(room_id)
+
rooms_result.extend(rooms)
events_result.extend(events)
- # add any children that we haven't already processed to the queue
- for edge_event in events:
- if edge_event["state_key"] not in processed_rooms:
- room_queue.append(edge_event["state_key"])
+ # add any children to the queue
+ room_queue.extend(edge_event["state_key"] for edge_event in events)
return {"rooms": rooms_result, "events": events_result}
@@ -200,6 +254,43 @@ class SpaceSummaryHandler:
)
return (room_entry,), events_result
+ async def _summarize_remote_room(
+ self,
+ room: "_RoomQueueEntry",
+ suggested_only: bool,
+ max_children: Optional[int],
+ exclude_rooms: Iterable[str],
+ ) -> Tuple[Sequence[JsonDict], Sequence[JsonDict]]:
+ room_id = room.room_id
+ logger.info("Requesting summary for %s via %s", room_id, room.via)
+
+ # we need to make the exclusion list json-serialisable
+ exclude_rooms = list(exclude_rooms)
+
+ via = itertools.islice(room.via, MAX_SERVERS_PER_SPACE)
+ try:
+ res = await self._federation_client.get_space_summary(
+ via,
+ room_id,
+ suggested_only=suggested_only,
+ max_rooms_per_space=max_children,
+ exclude_rooms=exclude_rooms,
+ )
+ except Exception as e:
+ logger.warning(
+ "Unable to get summary of %s via federation: %s",
+ room_id,
+ e,
+ exc_info=logger.isEnabledFor(logging.DEBUG),
+ )
+ return (), ()
+
+ return res.rooms, tuple(
+ ev.data
+ for ev in res.events
+ if ev.event_type == EventTypes.MSC1772_SPACE_CHILD
+ )
+
async def _is_room_accessible(self, room_id: str, requester: Optional[str]) -> bool:
# if we have an authenticated requesting user, first check if they are in the
# room
@@ -276,12 +367,24 @@ class SpaceSummaryHandler:
)
# filter out any events without a "via" (which implies it has been redacted)
- return (e for e in events if e.content.get("via"))
+ return (e for e in events if _has_valid_via(e))
@attr.s(frozen=True, slots=True)
class _RoomQueueEntry:
room_id = attr.ib(type=str)
+ via = attr.ib(type=Sequence[str])
+
+
+def _has_valid_via(e: EventBase) -> bool:
+ via = e.content.get("via")
+ if not via or not isinstance(via, Sequence):
+ return False
+ for v in via:
+ if not isinstance(v, str):
+ logger.debug("Ignoring edge event %s with invalid via entry", e.event_id)
+ return False
+ return True
def _is_suggested_child_event(edge_event: EventBase) -> bool:
|
