Prevent multiple upgrades on the same room at once (#5051)

Closes #4583

Does slightly less than #5045, which prevented a room from being upgraded multiple times, one after another. This PR still allows that, but just prevents two from happening at the same time.

Mostly just to mitigate the fact that servers are slow and it can take a moment for the room upgrade to actually complete. We don't want people sending another request to upgrade the room when really they just thought the first didn't go through.
This commit is contained in:
Andrew Morgan 2019-06-25 14:19:21 +01:00 committed by GitHub
parent 6fa36c22fa
commit ef8c62758c
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3 changed files with 92 additions and 53 deletions

1
changelog.d/5051.bugfix Normal file
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@ -0,0 +1 @@
Prevent >1 room upgrades happening simultaneously on the same room.

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@ -32,6 +32,7 @@ from synapse.storage.state import StateFilter
from synapse.types import RoomAlias, RoomID, RoomStreamToken, StreamToken, UserID from synapse.types import RoomAlias, RoomID, RoomStreamToken, StreamToken, UserID
from synapse.util import stringutils from synapse.util import stringutils
from synapse.util.async_helpers import Linearizer from synapse.util.async_helpers import Linearizer
from synapse.util.caches.response_cache import ResponseCache
from synapse.visibility import filter_events_for_client from synapse.visibility import filter_events_for_client
from ._base import BaseHandler from ._base import BaseHandler
@ -40,6 +41,8 @@ logger = logging.getLogger(__name__)
id_server_scheme = "https://" id_server_scheme = "https://"
FIVE_MINUTES_IN_MS = 5 * 60 * 1000
class RoomCreationHandler(BaseHandler): class RoomCreationHandler(BaseHandler):
@ -75,6 +78,12 @@ class RoomCreationHandler(BaseHandler):
# linearizer to stop two upgrades happening at once # linearizer to stop two upgrades happening at once
self._upgrade_linearizer = Linearizer("room_upgrade_linearizer") self._upgrade_linearizer = Linearizer("room_upgrade_linearizer")
# If a user tries to update the same room multiple times in quick
# succession, only process the first attempt and return its result to
# subsequent requests
self._upgrade_response_cache = ResponseCache(
hs, "room_upgrade", timeout_ms=FIVE_MINUTES_IN_MS
)
self._server_notices_mxid = hs.config.server_notices_mxid self._server_notices_mxid = hs.config.server_notices_mxid
self.third_party_event_rules = hs.get_third_party_event_rules() self.third_party_event_rules = hs.get_third_party_event_rules()
@ -95,67 +104,96 @@ class RoomCreationHandler(BaseHandler):
user_id = requester.user.to_string() user_id = requester.user.to_string()
with (yield self._upgrade_linearizer.queue(old_room_id)): # Check if this room is already being upgraded by another person
# start by allocating a new room id for key in self._upgrade_response_cache.pending_result_cache:
r = yield self.store.get_room(old_room_id) if key[0] == old_room_id and key[1] != user_id:
if r is None: # Two different people are trying to upgrade the same room.
raise NotFoundError("Unknown room id %s" % (old_room_id,)) # Send the second an error.
new_room_id = yield self._generate_room_id( #
creator_id=user_id, is_public=r["is_public"] # Note that this of course only gets caught if both users are
) # on the same homeserver.
raise SynapseError(
logger.info("Creating new room %s to replace %s", new_room_id, old_room_id) 400, "An upgrade for this room is currently in progress"
# we create and auth the tombstone event before properly creating the new
# room, to check our user has perms in the old room.
tombstone_event, tombstone_context = (
yield self.event_creation_handler.create_event(
requester,
{
"type": EventTypes.Tombstone,
"state_key": "",
"room_id": old_room_id,
"sender": user_id,
"content": {
"body": "This room has been replaced",
"replacement_room": new_room_id,
},
},
token_id=requester.access_token_id,
) )
)
old_room_version = yield self.store.get_room_version(old_room_id)
yield self.auth.check_from_context(
old_room_version, tombstone_event, tombstone_context
)
yield self.clone_existing_room( # Upgrade the room
#
# If this user has sent multiple upgrade requests for the same room
# and one of them is not complete yet, cache the response and
# return it to all subsequent requests
ret = yield self._upgrade_response_cache.wrap(
(old_room_id, user_id),
self._upgrade_room,
requester,
old_room_id,
new_version, # args for _upgrade_room
)
defer.returnValue(ret)
@defer.inlineCallbacks
def _upgrade_room(self, requester, old_room_id, new_version):
user_id = requester.user.to_string()
# start by allocating a new room id
r = yield self.store.get_room(old_room_id)
if r is None:
raise NotFoundError("Unknown room id %s" % (old_room_id,))
new_room_id = yield self._generate_room_id(
creator_id=user_id, is_public=r["is_public"]
)
logger.info("Creating new room %s to replace %s", new_room_id, old_room_id)
# we create and auth the tombstone event before properly creating the new
# room, to check our user has perms in the old room.
tombstone_event, tombstone_context = (
yield self.event_creation_handler.create_event(
requester, requester,
old_room_id=old_room_id, {
new_room_id=new_room_id, "type": EventTypes.Tombstone,
new_room_version=new_version, "state_key": "",
tombstone_event_id=tombstone_event.event_id, "room_id": old_room_id,
"sender": user_id,
"content": {
"body": "This room has been replaced",
"replacement_room": new_room_id,
},
},
token_id=requester.access_token_id,
) )
)
old_room_version = yield self.store.get_room_version(old_room_id)
yield self.auth.check_from_context(
old_room_version, tombstone_event, tombstone_context
)
# now send the tombstone yield self.clone_existing_room(
yield self.event_creation_handler.send_nonmember_event( requester,
requester, tombstone_event, tombstone_context old_room_id=old_room_id,
) new_room_id=new_room_id,
new_room_version=new_version,
tombstone_event_id=tombstone_event.event_id,
)
old_room_state = yield tombstone_context.get_current_state_ids(self.store) # now send the tombstone
yield self.event_creation_handler.send_nonmember_event(
requester, tombstone_event, tombstone_context
)
# update any aliases old_room_state = yield tombstone_context.get_current_state_ids(self.store)
yield self._move_aliases_to_new_room(
requester, old_room_id, new_room_id, old_room_state
)
# and finally, shut down the PLs in the old room, and update them in the new # update any aliases
# room. yield self._move_aliases_to_new_room(
yield self._update_upgraded_room_pls( requester, old_room_id, new_room_id, old_room_state
requester, old_room_id, new_room_id, old_room_state )
)
defer.returnValue(new_room_id) # and finally, shut down the PLs in the old room, and update them in the new
# room.
yield self._update_upgraded_room_pls(
requester, old_room_id, new_room_id, old_room_state
)
defer.returnValue(new_room_id)
@defer.inlineCallbacks @defer.inlineCallbacks
def _update_upgraded_room_pls( def _update_upgraded_room_pls(

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@ -137,7 +137,7 @@ class ResponseCache(object):
*args: positional parameters to pass to the callback, if it is used *args: positional parameters to pass to the callback, if it is used
**kwargs: named paramters to pass to the callback, if it is used **kwargs: named parameters to pass to the callback, if it is used
Returns: Returns:
twisted.internet.defer.Deferred: yieldable result twisted.internet.defer.Deferred: yieldable result