Commit Graph

67 Commits

Author SHA1 Message Date
Sean Quah
68db233f0c
Handle race between persisting an event and un-partial stating a room (#13100)
Whenever we want to persist an event, we first compute an event context,
which includes the state at the event and a flag indicating whether the
state is partial. After a lot of processing, we finally try to store the
event in the database, which can fail for partial state events when the
containing room has been un-partial stated in the meantime.

We detect the race as a foreign key constraint failure in the data store
layer and turn it into a special `PartialStateConflictError` exception,
which makes its way up to the method in which we computed the event
context.

To make things difficult, the exception needs to cross a replication
request: `/fed_send_events` for events coming over federation and
`/send_event` for events from clients. We transport the
`PartialStateConflictError` as a `409 Conflict` over replication and
turn `409`s back into `PartialStateConflictError`s on the worker making
the request.

All client events go through
`EventCreationHandler.handle_new_client_event`, which is called in
*a lot* of places. Instead of trying to update all the code which
creates client events, we turn the `PartialStateConflictError` into a
`429 Too Many Requests` in
`EventCreationHandler.handle_new_client_event` and hope that clients
take it as a hint to retry their request.

On the federation event side, there are 7 places which compute event
contexts. 4 of them use outlier event contexts:
`FederationEventHandler._auth_and_persist_outliers_inner`,
`FederationHandler.do_knock`, `FederationHandler.on_invite_request` and
`FederationHandler.do_remotely_reject_invite`. These events won't have
the partial state flag, so we do not need to do anything for then.

The remaining 3 paths which create events are
`FederationEventHandler.process_remote_join`,
`FederationEventHandler.on_send_membership_event` and
`FederationEventHandler._process_received_pdu`.

We can't experience the race in `process_remote_join`, unless we're
handling an additional join into a partial state room, which currently
blocks, so we make no attempt to handle it correctly.

`on_send_membership_event` is only called by
`FederationServer._on_send_membership_event`, so we catch the
`PartialStateConflictError` there and retry just once.

`_process_received_pdu` is called by `on_receive_pdu` for incoming
events and `_process_pulled_event` for backfill. The latter should never
try to persist partial state events, so we ignore it. We catch the
`PartialStateConflictError` in `on_receive_pdu` and retry just once.

Refering to the graph of code paths in
https://github.com/matrix-org/synapse/issues/12988#issuecomment-1156857648
may make the above make more sense.

Signed-off-by: Sean Quah <seanq@matrix.org>
2022-07-05 16:12:52 +01:00
Richard van der Hoff
6da861ae69
_process_received_pdu: Improve exception handling (#13145)
`_check_event_auth` is expected to raise `AuthError`s, so no need to log it
again.
2022-07-01 10:52:10 +01:00
Sean Quah
9372f6f842
Fix logging context misuse when we fail to persist a federation event (#13089)
When we fail to persist a federation event, we kick off a task to remove
its push actions in the background, using the current logging context.
Since we don't `await` that task, we may finish our logging context
before the task finishes. There's no reason to not `await` the task, so
let's do that.

Signed-off-by: Sean Quah <seanq@matrix.org>
2022-06-17 10:22:50 +01:00
Richard van der Hoff
8ecf6be1e1
Move some event auth checks out to a different method (#13065)
* Add auth events to events used in tests

* Move some event auth checks out to a different method

Some of the event auth checks apply to an event's auth_events, rather than the
state at the event - which means they can play no part in state
resolution. Move them out to a separate method.

* Rename check_auth_rules_for_event

Now it only checks the state-dependent auth rules, it needs a better name.
2022-06-15 19:48:22 +01:00
Richard van der Hoff
f68b5e5773 Merge branch 'rav/simplify_event_auth_interface' into develop 2022-06-13 11:34:59 +01:00
Richard van der Hoff
0d9d36b15c Remove room_version param from check_auth_rules_for_event
Instead, use the `room_version` property of the event we're checking.

The `room_version` was originally added as a parameter somewhere around #4482,
but really it's been redundant since #6875 added a `room_version` field to `EventBase`.
2022-06-12 23:13:10 +01:00
Richard van der Hoff
68be42f6b6 Remove room_version param from validate_event_for_room_version
Instead, use the `room_version` property of the event we're validating.

The `room_version` was originally added as a parameter somewhere around #4482,
but really it's been redundant since #6875 added a `room_version` field to `EventBase`.
2022-06-12 23:13:09 +01:00
Richard van der Hoff
7c6b2204d1
Faster joins: add issue links to the TODOs (#13004)
... to help us keep track of these things
2022-06-09 10:13:03 +00:00
Erik Johnston
e3163e2e11
Reduce the amount of state we pull from the DB (#12811) 2022-06-06 09:24:12 +01:00
Sean Quah
2fba1076c5
Faster room joins: Try other destinations when resyncing the state of a partial-state room (#12812)
Signed-off-by: Sean Quah <seanq@matrix.org>
2022-05-31 15:50:29 +01:00
Erik Johnston
1e453053cb
Rename storage classes (#12913) 2022-05-31 12:17:50 +00:00
Erik Johnston
b83bc5fab5
Pull out less state when handling gaps mk2 (#12852) 2022-05-26 09:48:12 +00:00
Erik Johnston
4660d9fdcf
Fix up state_store naming (#12871) 2022-05-25 12:59:04 +01:00
Eric Eastwood
7c2a78bb3b
Marker events as state - MSC2716 (#12718)
Sending marker events as state now so they are always able to be seen by homeservers (not lost in some timeline gap).

Part of [MSC2716](https://github.com/matrix-org/matrix-spec-proposals/pull/2716)

Complement tests: https://github.com/matrix-org/complement/pull/371

As initially discussed at https://github.com/matrix-org/matrix-spec-proposals/pull/2716#discussion_r782629097 and https://github.com/matrix-org/matrix-spec-proposals/pull/2716#discussion_r876684431

When someone joins a room, process all of the marker events we see in the current state. Marker events should be sent with a unique `state_key` so that they can all resolve in the current state to easily be discovered. Marker events as state

 - If we re-use the same `state_key` (like `""`), then we would have to fetch previous snapshots of state up through time to find all of the marker events. This way we can avoid all of that. This PR was originally doing this but then thought of the smarter way to tackle in an [out of band discussion with @erikjohnston](https://docs.google.com/document/d/1JJDuPfcPNX75fprdTWlxlaKjWOdbdJylbpZ03hzo638/edit#bookmark=id.sm92fqyq7vpp).
 - Also avoids state resolution conflicts where only one of the marker events win

As a homeserver, when we see new marker state, we know there is new history imported somewhere back in time and should process it to fetch the insertion event where the historical messages are and set it as an insertion extremity. This way we know where to backfill more messages when someone asks for scrollback.
2022-05-23 20:43:37 -05:00
Shay
71e8afe34d
Update EventContext get_current_event_ids and get_prev_event_ids to accept state filters and update calls where possible (#12791) 2022-05-20 09:54:12 +01:00
Patrick Cloke
a4c75918b3
Remove unneeded ActionGenerator class. (#12691)
It simply passes through to `BulkPushRuleEvaluator`, which can be
called directly instead.
2022-05-11 07:15:21 -04:00
Erik Johnston
c72d26c1e1
Refactor EventContext (#12689)
Refactor how the `EventContext` class works, with the intention of reducing the amount of state we fetch from the DB during event processing.

The idea here is to get rid of the cached `current_state_ids` and `prev_state_ids` that live in the `EventContext`, and instead defer straight to the database (and its caching). 

One change that may have a noticeable effect is that we now no longer prefill the `get_current_state_ids` cache on a state change. However, that query is relatively light, since its just a case of reading a table from the DB (unlike fetching state at an event which is more heavyweight). For deployments with workers this cache isn't even used.


Part of #12684
2022-05-10 19:43:13 +00:00
andrew do
01e625513a
remove constantly lib use and switch to enums. (#12624) 2022-05-04 11:26:11 +00:00
Richard van der Hoff
f5668f0b4a
Await un-partial-stating after a partial-state join (#12399)
When we join a room via the faster-joins mechanism, we end up with "partial
state" at some points on the event DAG. Many parts of the codebase need to
wait for the full state to load. So, we implement a mechanism to keep track of
which events have partial state, and wait for them to be fully-populated.
2022-04-21 07:42:03 +01:00
Richard van der Hoff
320186319a
Resync state after partial-state join (#12394)
We work through all the events with partial state, updating the state at each
of them. Once it's done, we recalculate the state for the whole room, and then
mark the room as having complete state.
2022-04-12 13:23:43 +00:00
Sean Quah
800ba87cc8
Refactor and convert Linearizer to async (#12357)
Refactor and convert `Linearizer` to async. This makes a `Linearizer`
cancellation bug easier to fix.

Also refactor to use an async context manager, which eliminates an
unlikely footgun where code that doesn't immediately use the context
manager could forget to release the lock.

Signed-off-by: Sean Quah <seanq@element.io>
2022-04-05 15:43:52 +01:00
Richard van der Hoff
9b43df1f7b
Optimise _get_state_after_missing_prev_event: use /state (#12040)
If we're missing most of the events in the room state, then we may as well call the /state endpoint, instead of individually requesting each and every event.
2022-04-01 12:53:42 +01:00
Richard van der Hoff
9b67715bc3
Disable proactive sends for remote joins (#12330)
Do not attempt to send remote joins out over federation. Normally, it will do
nothing; occasionally, it will do the wrong thing.
2022-03-30 12:04:35 +01:00
Richard van der Hoff
e2e1d90a5e
Faster joins: persist to database (#12012)
When we get a partial_state response from send_join, store information in the
database about it:
 * store a record about the room as a whole having partial state, and stash the
   list of member servers too.
 * flag the join event itself as having partial state
 * also, for any new events whose prev-events are partial-stated, note that
   they will *also* be partial-stated.

We don't yet make any attempt to interpret this data, so API calls (and a bunch
of other things) are just going to get incorrect data.
2022-03-01 12:49:54 +00:00
Richard van der Hoff
e24ff8ebe3
Remove HomeServer.get_datastore() (#12031)
The presence of this method was confusing, and mostly present for backwards
compatibility. Let's get rid of it.

Part of #11733
2022-02-23 11:04:02 +00:00
Richard van der Hoff
696acd3515
send_join response: get create event from state, not auth_chain (#12005)
msc3706 proposes changing the `/send_join` response:

> Any events returned within `state` can be omitted from `auth_chain`.

Currently, we rely on `m.room.create` being returned in `auth_chain`, but since
the `m.room.create` event must necessarily be part of the state, the above
change will break this.

In short, let's look for `m.room.create` in `state` rather than `auth_chain`.
2022-02-17 11:59:26 +00:00
Richard van der Hoff
bab2394aa9
_auth_and_persist_outliers: drop events we have already seen (#11994)
We already have two copies of this code, in 2/3 of the callers of
`_auth_and_persist_outliers`. Before I add a third, let's push it down.
2022-02-15 14:33:28 +00:00
Eric Eastwood
fef2e792be
Fix historical messages backfilling in random order on remote homeservers (MSC2716) (#11114)
Fix https://github.com/matrix-org/synapse/issues/11091
Fix https://github.com/matrix-org/synapse/issues/10764 (side-stepping the issue because we no longer have to deal with `fake_prev_event_id`)

 1. Made the `/backfill` response return messages in `(depth, stream_ordering)` order (previously only sorted by `depth`)
    - Technically, it shouldn't really matter how `/backfill` returns things but I'm just trying to make the `stream_ordering` a little more consistent from the origin to the remote homeservers in order to get the order of messages from `/messages` consistent ([sorted by `(topological_ordering, stream_ordering)`](https://github.com/matrix-org/synapse/blob/develop/docs/development/room-dag-concepts.md#depth-and-stream-ordering)).
    - Even now that we return backfilled messages in order, it still doesn't guarantee the same `stream_ordering` (and more importantly the [`/messages` order](https://github.com/matrix-org/synapse/blob/develop/docs/development/room-dag-concepts.md#depth-and-stream-ordering)) on the other server. For example, if a room has a bunch of history imported and someone visits a permalink to a historical message back in time, their homeserver will skip over the historical messages in between and insert the permalink as the next message in the `stream_order` and totally throw off the sort.
       - This will be even more the case when we add the [MSC3030 jump to date API endpoint](https://github.com/matrix-org/matrix-doc/pull/3030) so the static archives can navigate and jump to a certain date.
       - We're solving this in the future by switching to [online topological ordering](https://github.com/matrix-org/gomatrixserverlib/issues/187) and [chunking](https://github.com/matrix-org/synapse/issues/3785) which by its nature will apply retroactively to fix any inconsistencies introduced by people permalinking
 2. As we're navigating `prev_events` to return in `/backfill`, we order by `depth` first (newest -> oldest) and now also tie-break based on the `stream_ordering` (newest -> oldest). This is technically important because MSC2716 inserts a bunch of historical messages at the same `depth` so it's best to be prescriptive about which ones we should process first. In reality, I think the code already looped over the historical messages as expected because the database is already in order.
 3. Making the historical state chain and historical event chain float on their own by having no `prev_events` instead of a fake `prev_event` which caused backfill to get clogged with an unresolvable event. Fixes https://github.com/matrix-org/synapse/issues/11091 and https://github.com/matrix-org/synapse/issues/10764
 4. We no longer find connected insertion events by finding a potential `prev_event` connection to the current event we're iterating over. We now solely rely on marker events which when processed, add the insertion event as an extremity and the federating homeserver can ask about it when time calls.
    - Related discussion, https://github.com/matrix-org/synapse/pull/11114#discussion_r741514793


Before | After
--- | ---
![](https://user-images.githubusercontent.com/558581/139218681-b465c862-5c49-4702-a59e-466733b0cf45.png) | ![](https://user-images.githubusercontent.com/558581/146453159-a1609e0a-8324-439d-ae44-e4bce43ac6d1.png)



#### Why aren't we sorting topologically when receiving backfill events?

> The main reason we're going to opt to not sort topologically when receiving backfill events is because it's probably best to do whatever is easiest to make it just work. People will probably have opinions once they look at [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716) which could change whatever implementation anyway.
> 
> As mentioned, ideally we would do this but code necessary to make the fake edges but it gets confusing and gives an impression of “just whyyyy” (feels icky). This problem also dissolves with online topological ordering.
>
> -- https://github.com/matrix-org/synapse/pull/11114#discussion_r741517138

See https://github.com/matrix-org/synapse/pull/11114#discussion_r739610091 for the technical difficulties
2022-02-07 15:54:13 -06:00
Richard van der Hoff
251b5567ec
Remove log_function and its uses (#11761)
I've never found this terribly useful. I think it was added in the early days
of Synapse, without much thought as to what would actually be useful to log,
and has just been cargo-culted ever since.

Rather, it tends to clutter up debug logs with useless information.
2022-01-18 13:06:04 +00:00
Richard van der Hoff
0fb3dd0830
Refactor the way we set outlier (#11634)
* `_auth_and_persist_outliers`: mark persisted events as outliers

Mark any events that get persisted via `_auth_and_persist_outliers` as, well,
outliers.

Currently this will be a no-op as everything will already be flagged as an
outlier, but I'm going to change that.

* `process_remote_join`: stop flagging as outlier

The events are now flagged as outliers later on, by `_auth_and_persist_outliers`.

* `send_join`: remove `outlier=True`

The events created here are returned in the result of `send_join` to
`FederationHandler.do_invite_join`. From there they are passed into
`FederationEventHandler.process_remote_join`, which passes them to
`_auth_and_persist_outliers`... which sets the `outlier` flag.

* `get_event_auth`: remove `outlier=True`

stop flagging the events returned by `get_event_auth` as outliers. This method
is only called by `_get_remote_auth_chain_for_event`, which passes the results
into `_auth_and_persist_outliers`, which will flag them as outliers.

* `_get_remote_auth_chain_for_event`: remove `outlier=True`

we pass all the events into `_auth_and_persist_outliers`, which will now flag
the events as outliers.

* `_check_sigs_and_hash_and_fetch`: remove unused `outlier` parameter

This param is now never set to True, so we can remove it.

* `_check_sigs_and_hash_and_fetch_one`: remove unused `outlier` param

This is no longer set anywhere, so we can remove it.

* `get_pdu`: remove unused `outlier` parameter

... and chase it down into `get_pdu_from_destination_raw`.

* `event_from_pdu_json`: remove redundant `outlier` param

This is never set to `True`, so can be removed.

* changelog

* update docstring
2022-01-05 12:26:11 +00:00
Richard van der Hoff
878aa55293
FederationClient.backfill: stop flagging events as outliers (#11632)
Events returned by `backfill` should not be flagged as outliers.

Fixes:

```
AssertionError: null
  File "synapse/handlers/federation.py", line 313, in try_backfill
    dom, room_id, limit=100, extremities=extremities
  File "synapse/handlers/federation_event.py", line 517, in backfill
    await self._process_pulled_events(dest, events, backfilled=True)
  File "synapse/handlers/federation_event.py", line 642, in _process_pulled_events
    await self._process_pulled_event(origin, ev, backfilled=backfilled)
  File "synapse/handlers/federation_event.py", line 669, in _process_pulled_event
    assert not event.internal_metadata.is_outlier()
```

See https://sentry.matrix.org/sentry/synapse-matrixorg/issues/231992

Fixes #8894.
2022-01-04 16:31:32 +00:00
Richard van der Hoff
2359ee3864
Remove redundant get_current_events_token (#11643)
* Push `get_room_{min,max_stream_ordering}` into StreamStore

Both implementations of this are identical, so we may as well push it down and
get rid of the abstract base class nonsense.

* Remove redundant `StreamStore` class

This is empty now

* Remove redundant `get_current_events_token`

This was an exact duplicate of `get_room_max_stream_ordering`, so let's get rid
of it.

* newsfile
2022-01-04 16:10:27 +00:00
Richard van der Hoff
73cbb284b9
Remove redundant parameters on _check_event_auth (#11292)
as of #11012, these parameters are unused.
2021-11-10 14:16:06 +00:00
Patrick Cloke
c01bc5f43d
Add remaining type hints to synapse.events. (#11098) 2021-11-02 09:55:52 -04:00
reivilibre
75ca0a6168
Annotate log_function decorator (#10943)
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
2021-10-27 17:27:23 +01:00
Brendan Abolivier
c7a5e49664
Implement an on_new_event callback (#11126)
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
2021-10-26 15:17:36 +02:00
Richard van der Hoff
da957a60e8
Ensure that we correctly auth events returned by send_join (#11012)
This is the final piece of the jigsaw for #9595. As with other changes before this one (eg #10771), we need to make sure that we auth the auth events in the right order, and actually check that their predecessors haven't been rejected.

To do this I've reused the existing code we use when persisting outliers elsewhere.

I've removed the code for attempting to fetch missing auth_events - the events should have been present in the send_join response, so the likely reason they are missing is that we couldn't verify them, so requesting them again is unlikely to help. Instead, we simply drop any state which relies on those auth events, as we do at a backwards-extremity. See also matrix-org/complement#216 for a test for this.
2021-10-25 15:21:09 +01:00
Richard van der Hoff
0930e9ae12
Clean up _update_auth_events_and_context_for_auth (#11122)
Remove some redundant code, and generally simplify.
2021-10-20 18:22:40 +01:00
Richard van der Hoff
f3efa0036b
Move _persist_auth_tree into FederationEventHandler (#11115)
This is just a lift-and-shift, because it fits more naturally here. We do
rename it to `process_remote_join` at the same time though.
2021-10-19 10:24:09 +01:00
Richard van der Hoff
0170774b19
Rename _auth_and_persist_fetched_events (#11116)
... to `_auth_and_persist_outliers`, since that reflects its purpose better.
2021-10-19 10:23:55 +01:00
Richard van der Hoff
cc33d9eee2
Check auth on received events' auth_events (#11001)
Currently, when we receive an event whose auth_events differ from those we expect, we state-resolve between the two state sets, and check that the event passes auth based on the resolved state.

This means that it's possible for us to accept events which don't pass auth at their declared auth_events (or where the auth events themselves were rejected), leading to problems down the line like #10083.

This change means we will:

 * ignore any events where we cannot find the auth events
 * reject any events whose auth events were rejected
 * reject any events which do not pass auth at their declared auth_events.

Together with a whole raft of previous work, this is a partial fix to #9595.

Fixes #6643.

Based on #11009.
2021-10-18 18:29:37 +01:00
Richard van der Hoff
a5d2ea3d08
Check *all* auth events for room id and rejection (#11009)
This fixes a bug where we would accept an event whose `auth_events` include
rejected events, if the rejected event was shadowed by another `auth_event`
with same `(type, state_key)`.

The approach is to pass a list of auth events into
`check_auth_rules_for_event` instead of a dict, which of course means updating
the call sites.

This is an extension of #10956.
2021-10-18 18:28:30 +01:00
Richard van der Hoff
e8f24b6c35
_run_push_actions_and_persist_event: handle no min_depth (#11014)
Make sure that we correctly handle rooms where we do not yet have a
`min_depth`, and also add some comments and logging.
2021-10-18 17:17:15 +01:00
Eric Eastwood
daf498e099
Fix 500 error on /messages when we accumulate more than 5 backward extremities (#11027)
Found while working on the Gitter backfill script and noticed
it only happened after we sent 7 batches, https://gitlab.com/gitterHQ/webapp/-/merge_requests/2229#note_665906390

When there are more than 5 backward extremities for a given depth,
backfill will throw an error because we sliced the extremity list
to 5 but then try to iterate over the full list. This causes
us to look for state that we never fetched and we get a `KeyError`.

Before when calling `/messages` when there are more than 5 backward extremities:
```
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 258, in _async_render_wrapper
    callback_return = await self._async_render(request)
  File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 446, in _async_render
    callback_return = await raw_callback_return
  File "/usr/local/lib/python3.8/site-packages/synapse/rest/client/room.py", line 580, in on_GET
    msgs = await self.pagination_handler.get_messages(
  File "/usr/local/lib/python3.8/site-packages/synapse/handlers/pagination.py", line 396, in get_messages
    await self.hs.get_federation_handler().maybe_backfill(
  File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 133, in maybe_backfill
    return await self._maybe_backfill_inner(room_id, current_depth, limit)
  File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 386, in _maybe_backfill_inner
    likely_extremeties_domains = get_domains_from_state(states[e_id])
KeyError: '$zpFflMEBtZdgcMQWTakaVItTLMjLFdKcRWUPHbbSZJl'
```
2021-10-14 18:53:45 -05:00
Richard van der Hoff
96fe77c254
Improve the logging in _auth_and_persist_outliers (#11010)
Include the event ids being peristed
2021-10-07 11:43:25 +00:00
Richard van der Hoff
86af6b2f0e
Add a comment in _process_received_pdu (#11011) 2021-10-07 12:20:03 +01:00
Eric Eastwood
392863fbf1
Fix logic flaw preventing tracking of MSC2716 events in existing room versions (#10962)
We correctly allowed using the MSC2716 batch endpoint for
the room creator in existing room versions but accidentally didn't track
the events because of a logic flaw.

This prevented you from connecting subsequent chunks together because it would
throw the unknown batch ID error.

We only want to process MSC2716 events when:

 - The room version supports MSC2716
 - Any room where the homeserver has the `msc2716_enabled` experimental feature enabled and the event is from the room creator
2021-10-05 11:51:57 -05:00
Richard van der Hoff
787af4a106
Host cache_joined_hosts_for_event to caller (#10986)
`_check_event_auth` is only called in two places, and only one of those sets
`send_on_behalf_of`. Warming the cache isn't really part of auth anyway, so
moving it out makes a lot more sense.
2021-10-05 13:01:41 +01:00
Richard van der Hoff
d099535deb
_update_auth_events_and_context_for_auth: add some comments (#10987)
Add some more comments about wtf is going on here.
2021-10-05 12:50:38 +01:00
Richard van der Hoff
cb88ed912b
_check_event_auth: move event validation earlier (#10988)
There's little point in doing a fancy state reconciliation dance if the event
itself is invalid.

Likewise, there's no point checking it again in `_check_for_soft_fail`.
2021-10-05 12:50:07 +01:00