Add debug logs to figure out why an event was filtered (#14095)

Spawned while investigating https://github.com/matrix-org/synapse/issues/13944

This way we might get some more context whenever an `403 Forbidden - body: {"errcode":"M_FORBIDDEN","error":"You don't have permission to access that event."}` error is produced.

`log_config.yaml`
```yaml
loggers:
    synapse:
        level: INFO

    synapse.visibility:
        level: DEBUG
```
This commit is contained in:
Eric Eastwood 2022-10-17 16:02:39 -05:00 committed by GitHub
parent 6fee2f49f3
commit 2c63cdcc3f
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2 changed files with 32 additions and 1 deletions

1
changelog.d/14095.misc Normal file
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@ -0,0 +1 @@
Add debug logs to figure out why an event was filtered out of the client response.

View file

@ -84,7 +84,15 @@ async def filter_events_for_client(
"""
# Filter out events that have been soft failed so that we don't relay them
# to clients.
events_before_filtering = events
events = [e for e in events if not e.internal_metadata.is_soft_failed()]
if len(events_before_filtering) != len(events):
if logger.isEnabledFor(logging.DEBUG):
logger.debug(
"filter_events_for_client: Filtered out soft-failed events: Before=%s, After=%s",
[event.event_id for event in events_before_filtering],
[event.event_id for event in events],
)
types = (_HISTORY_VIS_KEY, (EventTypes.Member, user_id))
@ -301,6 +309,10 @@ def _check_client_allowed_to_see_event(
_check_filter_send_to_client(event, clock, retention_policy, sender_ignored)
== _CheckFilter.DENIED
):
logger.debug(
"_check_client_allowed_to_see_event(event=%s): Filtered out event because `_check_filter_send_to_client` returned `_CheckFilter.DENIED`",
event.event_id,
)
return None
if event.event_id in always_include_ids:
@ -312,9 +324,17 @@ def _check_client_allowed_to_see_event(
# for out-of-band membership events (eg, incoming invites, or rejections of
# said invite) for the user themselves.
if event.type == EventTypes.Member and event.state_key == user_id:
logger.debug("Returning out-of-band-membership event %s", event)
logger.debug(
"_check_client_allowed_to_see_event(event=%s): Returning out-of-band-membership event %s",
event.event_id,
event,
)
return event
logger.debug(
"_check_client_allowed_to_see_event(event=%s): Filtered out event because it's an outlier",
event.event_id,
)
return None
if state is None:
@ -337,11 +357,21 @@ def _check_client_allowed_to_see_event(
membership_result = _check_membership(user_id, event, visibility, state, is_peeking)
if not membership_result.allowed:
logger.debug(
"_check_client_allowed_to_see_event(event=%s): Filtered out event because the user can't see the event because of their membership, membership_result.allowed=%s membership_result.joined=%s",
event.event_id,
membership_result.allowed,
membership_result.joined,
)
return None
# If the sender has been erased and the user was not joined at the time, we
# must only return the redacted form.
if sender_erased and not membership_result.joined:
logger.debug(
"_check_client_allowed_to_see_event(event=%s): Returning pruned event because `sender_erased` and the user was not joined at the time",
event.event_id,
)
event = prune_event(event)
return event