diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/api/room_versions.py | 20 | ||||
| -rw-r--r-- | synapse/config/server.py | 16 | ||||
| -rw-r--r-- | synapse/config/tls.py | 12 | ||||
| -rw-r--r-- | synapse/crypto/keyring.py | 112 | ||||
| -rw-r--r-- | synapse/federation/federation_base.py | 41 | ||||
| -rw-r--r-- | synapse/federation/transport/server.py | 4 | ||||
| -rw-r--r-- | synapse/groups/attestations.py | 4 | ||||
| -rw-r--r-- | synapse/handlers/federation.py | 58 | ||||
| -rw-r--r-- | synapse/handlers/presence.py | 11 | ||||
| -rw-r--r-- | synapse/handlers/stats.py | 18 | ||||
| -rw-r--r-- | synapse/handlers/sync.py | 34 | ||||
| -rw-r--r-- | synapse/rest/client/versions.py | 1 | ||||
| -rw-r--r-- | synapse/storage/events_worker.py | 37 |
13 files changed, 258 insertions, 110 deletions
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py index 4085bd10b9..d644803d38 100644 --- a/synapse/api/room_versions.py +++ b/synapse/api/room_versions.py @@ -50,6 +50,7 @@ class RoomVersion(object): disposition = attr.ib() # str; one of the RoomDispositions event_format = attr.ib() # int; one of the EventFormatVersions state_res = attr.ib() # int; one of the StateResolutionVersions + enforce_key_validity = attr.ib() # bool class RoomVersions(object): @@ -58,30 +59,35 @@ class RoomVersions(object): RoomDisposition.STABLE, EventFormatVersions.V1, StateResolutionVersions.V1, - ) - STATE_V2_TEST = RoomVersion( - "state-v2-test", - RoomDisposition.UNSTABLE, - EventFormatVersions.V1, - StateResolutionVersions.V2, + enforce_key_validity=False, ) V2 = RoomVersion( "2", RoomDisposition.STABLE, EventFormatVersions.V1, StateResolutionVersions.V2, + enforce_key_validity=False, ) V3 = RoomVersion( "3", RoomDisposition.STABLE, EventFormatVersions.V2, StateResolutionVersions.V2, + enforce_key_validity=False, ) V4 = RoomVersion( "4", RoomDisposition.STABLE, EventFormatVersions.V3, StateResolutionVersions.V2, + enforce_key_validity=False, + ) + V5 = RoomVersion( + "5", + RoomDisposition.STABLE, + EventFormatVersions.V3, + StateResolutionVersions.V2, + enforce_key_validity=True, ) @@ -90,7 +96,7 @@ KNOWN_ROOM_VERSIONS = { RoomVersions.V1, RoomVersions.V2, RoomVersions.V3, - RoomVersions.STATE_V2_TEST, RoomVersions.V4, + RoomVersions.V5, ) } # type: dict[str, RoomVersion] diff --git a/synapse/config/server.py b/synapse/config/server.py index e763e19e15..334921d421 100644 --- a/synapse/config/server.py +++ b/synapse/config/server.py @@ -585,6 +585,22 @@ class ServerConfig(Config): # Monthly Active User Blocking # + # Used in cases where the admin or server owner wants to limit to the + # number of monthly active users. + # + # 'limit_usage_by_mau' disables/enables monthly active user blocking. When + # anabled and a limit is reached the server returns a 'ResourceLimitError' + # with error type Codes.RESOURCE_LIMIT_EXCEEDED + # + # 'max_mau_value' is the hard limit of monthly active users above which + # the server will start blocking user actions. + # + # 'mau_trial_days' is a means to add a grace period for active users. It + # means that users must be active for this number of days before they + # can be considered active and guards against the case where lots of users + # sign up in a short space of time never to return after their initial + # session. + # #limit_usage_by_mau: False #max_mau_value: 50 #mau_trial_days: 2 diff --git a/synapse/config/tls.py b/synapse/config/tls.py index 72dd5926f9..658f9dd361 100644 --- a/synapse/config/tls.py +++ b/synapse/config/tls.py @@ -74,7 +74,7 @@ class TlsConfig(Config): # Whether to verify certificates on outbound federation traffic self.federation_verify_certificates = config.get( - "federation_verify_certificates", False, + "federation_verify_certificates", True, ) # Whitelist of domains to not verify certificates for @@ -107,7 +107,7 @@ class TlsConfig(Config): certs = [] for ca_file in custom_ca_list: logger.debug("Reading custom CA certificate file: %s", ca_file) - content = self.read_file(ca_file) + content = self.read_file(ca_file, "federation_custom_ca_list") # Parse the CA certificates try: @@ -241,12 +241,12 @@ class TlsConfig(Config): # #tls_private_key_path: "%(tls_private_key_path)s" - # Whether to verify TLS certificates when sending federation traffic. + # Whether to verify TLS server certificates for outbound federation requests. # - # This currently defaults to `false`, however this will change in - # Synapse 1.0 when valid federation certificates will be required. + # Defaults to `true`. To disable certificate verification, uncomment the + # following line. # - #federation_verify_certificates: true + #federation_verify_certificates: false # Skip federation certificate verification on the following whitelist # of domains. diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py index e94e71bdad..2b6b5913bc 100644 --- a/synapse/crypto/keyring.py +++ b/synapse/crypto/keyring.py @@ -60,9 +60,9 @@ logger = logging.getLogger(__name__) @attr.s(slots=True, cmp=False) -class VerifyKeyRequest(object): +class VerifyJsonRequest(object): """ - A request for a verify key to verify a JSON object. + A request to verify a JSON object. Attributes: server_name(str): The name of the server to verify against. @@ -85,11 +85,15 @@ class VerifyKeyRequest(object): """ server_name = attr.ib() - key_ids = attr.ib() json_object = attr.ib() minimum_valid_until_ts = attr.ib() + request_name = attr.ib() + key_ids = attr.ib(init=False) key_ready = attr.ib(default=attr.Factory(defer.Deferred)) + def __attrs_post_init__(self): + self.key_ids = signature_ids(self.json_object, self.server_name) + class KeyLookupError(ValueError): pass @@ -114,7 +118,9 @@ class Keyring(object): # These are regular, logcontext-agnostic Deferreds. self.key_downloads = {} - def verify_json_for_server(self, server_name, json_object, validity_time): + def verify_json_for_server( + self, server_name, json_object, validity_time, request_name + ): """Verify that a JSON object has been signed by a given server Args: @@ -125,24 +131,31 @@ class Keyring(object): validity_time (int): timestamp at which we require the signing key to be valid. (0 implies we don't care) + request_name (str): an identifier for this json object (eg, an event id) + for logging. + Returns: Deferred[None]: completes if the the object was correctly signed, otherwise errbacks with an error """ - req = server_name, json_object, validity_time - - return logcontext.make_deferred_yieldable( - self.verify_json_objects_for_server((req,))[0] - ) + req = VerifyJsonRequest(server_name, json_object, validity_time, request_name) + requests = (req,) + return logcontext.make_deferred_yieldable(self._verify_objects(requests)[0]) def verify_json_objects_for_server(self, server_and_json): """Bulk verifies signatures of json objects, bulk fetching keys as necessary. Args: - server_and_json (iterable[Tuple[str, dict, int]): - Iterable of triplets of (server_name, json_object, validity_time) - validity_time is a timestamp at which the signing key must be valid. + server_and_json (iterable[Tuple[str, dict, int, str]): + Iterable of (server_name, json_object, validity_time, request_name) + tuples. + + validity_time is a timestamp at which the signing key must be + valid. + + request_name is an identifier for this json object (eg, an event id) + for logging. Returns: List<Deferred[None]>: for each input triplet, a deferred indicating success @@ -150,38 +163,54 @@ class Keyring(object): server_name. The deferreds run their callbacks in the sentinel logcontext. """ - # a list of VerifyKeyRequests - verify_requests = [] + return self._verify_objects( + VerifyJsonRequest(server_name, json_object, validity_time, request_name) + for server_name, json_object, validity_time, request_name in server_and_json + ) + + def _verify_objects(self, verify_requests): + """Does the work of verify_json_[objects_]for_server + + + Args: + verify_requests (iterable[VerifyJsonRequest]): + Iterable of verification requests. + + Returns: + List<Deferred[None]>: for each input item, a deferred indicating success + or failure to verify each json object's signature for the given + server_name. The deferreds run their callbacks in the sentinel + logcontext. + """ + # a list of VerifyJsonRequests which are awaiting a key lookup + key_lookups = [] handle = preserve_fn(_handle_key_deferred) - def process(server_name, json_object, validity_time): + def process(verify_request): """Process an entry in the request list - Given a (server_name, json_object, validity_time) triplet from the request - list, adds a key request to verify_requests, and returns a deferred which + Adds a key request to key_lookups, and returns a deferred which will complete or fail (in the sentinel context) when verification completes. """ - key_ids = signature_ids(json_object, server_name) - - if not key_ids: + if not verify_request.key_ids: return defer.fail( SynapseError( - 400, "Not signed by %s" % (server_name,), Codes.UNAUTHORIZED + 400, + "Not signed by %s" % (verify_request.server_name,), + Codes.UNAUTHORIZED, ) ) logger.debug( - "Verifying for %s with key_ids %s, min_validity %i", - server_name, - key_ids, - validity_time, + "Verifying %s for %s with key_ids %s, min_validity %i", + verify_request.request_name, + verify_request.server_name, + verify_request.key_ids, + verify_request.minimum_valid_until_ts, ) # add the key request to the queue, but don't start it off yet. - verify_request = VerifyKeyRequest( - server_name, key_ids, json_object, validity_time - ) - verify_requests.append(verify_request) + key_lookups.append(verify_request) # now run _handle_key_deferred, which will wait for the key request # to complete and then do the verification. @@ -190,13 +219,10 @@ class Keyring(object): # wrap it with preserve_fn (aka run_in_background) return handle(verify_request) - results = [ - process(server_name, json_object, validity_time) - for server_name, json_object, validity_time in server_and_json - ] + results = [process(r) for r in verify_requests] - if verify_requests: - run_in_background(self._start_key_lookups, verify_requests) + if key_lookups: + run_in_background(self._start_key_lookups, key_lookups) return results @@ -207,7 +233,7 @@ class Keyring(object): Once each fetch completes, verify_request.key_ready will be resolved. Args: - verify_requests (List[VerifyKeyRequest]): + verify_requests (List[VerifyJsonRequest]): """ try: @@ -308,7 +334,7 @@ class Keyring(object): with a SynapseError if none of the keys are found. Args: - verify_requests (list[VerifyKeyRequest]): list of verify requests + verify_requests (list[VerifyJsonRequest]): list of verify requests """ remaining_requests = set( @@ -357,7 +383,7 @@ class Keyring(object): Args: fetcher (KeyFetcher): fetcher to use to fetch the keys - remaining_requests (set[VerifyKeyRequest]): outstanding key requests. + remaining_requests (set[VerifyJsonRequest]): outstanding key requests. Any successfully-completed requests will be removed from the list. """ # dict[str, dict[str, int]]: keys to fetch. @@ -376,7 +402,7 @@ class Keyring(object): # the requests. keys_for_server[key_id] = max( keys_for_server.get(key_id, -1), - verify_request.minimum_valid_until_ts + verify_request.minimum_valid_until_ts, ) results = yield fetcher.get_keys(missing_keys) @@ -386,7 +412,7 @@ class Keyring(object): server_name = verify_request.server_name # see if any of the keys we got this time are sufficient to - # complete this VerifyKeyRequest. + # complete this VerifyJsonRequest. result_keys = results.get(server_name, {}) for key_id in verify_request.key_ids: fetch_key_result = result_keys.get(key_id) @@ -454,9 +480,7 @@ class BaseV2KeyFetcher(object): self.config = hs.get_config() @defer.inlineCallbacks - def process_v2_response( - self, from_server, response_json, time_added_ms - ): + def process_v2_response(self, from_server, response_json, time_added_ms): """Parse a 'Server Keys' structure from the result of a /key request This is used to parse either the entirety of the response from @@ -852,7 +876,7 @@ def _handle_key_deferred(verify_request): """Waits for the key to become available, and then performs a verification Args: - verify_request (VerifyKeyRequest): + verify_request (VerifyJsonRequest): Returns: Deferred[None] diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py index 4b38f7c759..fc5cfb7d83 100644 --- a/synapse/federation/federation_base.py +++ b/synapse/federation/federation_base.py @@ -223,9 +223,6 @@ def _check_sigs_on_pdus(keyring, room_version, pdus): the signatures are valid, or fail (with a SynapseError) if not. """ - # (currently this is written assuming the v1 room structure; we'll probably want a - # separate function for checking v2 rooms) - # we want to check that the event is signed by: # # (a) the sender's server @@ -257,6 +254,10 @@ def _check_sigs_on_pdus(keyring, room_version, pdus): for p in pdus ] + v = KNOWN_ROOM_VERSIONS.get(room_version) + if not v: + raise RuntimeError("Unrecognized room version %s" % (room_version,)) + # First we check that the sender event is signed by the sender's domain # (except if its a 3pid invite, in which case it may be sent by any server) pdus_to_check_sender = [ @@ -264,10 +265,17 @@ def _check_sigs_on_pdus(keyring, room_version, pdus): if not _is_invite_via_3pid(p.pdu) ] - more_deferreds = keyring.verify_json_objects_for_server([ - (p.sender_domain, p.redacted_pdu_json, 0) - for p in pdus_to_check_sender - ]) + more_deferreds = keyring.verify_json_objects_for_server( + [ + ( + p.sender_domain, + p.redacted_pdu_json, + p.pdu.origin_server_ts if v.enforce_key_validity else 0, + p.pdu.event_id, + ) + for p in pdus_to_check_sender + ] + ) def sender_err(e, pdu_to_check): errmsg = "event id %s: unable to verify signature for sender %s: %s" % ( @@ -287,20 +295,23 @@ def _check_sigs_on_pdus(keyring, room_version, pdus): # event id's domain (normally only the case for joins/leaves), and add additional # checks. Only do this if the room version has a concept of event ID domain # (ie, the room version uses old-style non-hash event IDs). - v = KNOWN_ROOM_VERSIONS.get(room_version) - if not v: - raise RuntimeError("Unrecognized room version %s" % (room_version,)) - if v.event_format == EventFormatVersions.V1: pdus_to_check_event_id = [ p for p in pdus_to_check if p.sender_domain != get_domain_from_id(p.pdu.event_id) ] - more_deferreds = keyring.verify_json_objects_for_server([ - (get_domain_from_id(p.pdu.event_id), p.redacted_pdu_json, 0) - for p in pdus_to_check_event_id - ]) + more_deferreds = keyring.verify_json_objects_for_server( + [ + ( + get_domain_from_id(p.pdu.event_id), + p.redacted_pdu_json, + p.pdu.origin_server_ts if v.enforce_key_validity else 0, + p.pdu.event_id, + ) + for p in pdus_to_check_event_id + ] + ) def event_err(e, pdu_to_check): errmsg = ( diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py index 0db8858cf1..949a5fb2aa 100644 --- a/synapse/federation/transport/server.py +++ b/synapse/federation/transport/server.py @@ -140,7 +140,9 @@ class Authenticator(object): 401, "Missing Authorization headers", Codes.UNAUTHORIZED, ) - yield self.keyring.verify_json_for_server(origin, json_request, now) + yield self.keyring.verify_json_for_server( + origin, json_request, now, "Incoming request" + ) logger.info("Request from %s", origin) request.authenticated_entity = origin diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py index fa6b641ee1..e5dda1975f 100644 --- a/synapse/groups/attestations.py +++ b/synapse/groups/attestations.py @@ -101,7 +101,9 @@ class GroupAttestationSigning(object): if valid_until_ms < now: raise SynapseError(400, "Attestation expired") - yield self.keyring.verify_json_for_server(server_name, attestation, now) + yield self.keyring.verify_json_for_server( + server_name, attestation, now, "Group attestation" + ) def create_attestation(self, group_id, user_id): """Create an attestation for the group_id and user_id with default diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index cf4fad7de0..ac5ca79143 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -35,6 +35,7 @@ from synapse.api.errors import ( CodeMessageException, FederationDeniedError, FederationError, + RequestSendFailed, StoreError, SynapseError, ) @@ -2027,9 +2028,21 @@ class FederationHandler(BaseHandler): """ room_version = yield self.store.get_room_version(event.room_id) - yield self._update_auth_events_and_context_for_auth( - origin, event, context, auth_events - ) + try: + yield self._update_auth_events_and_context_for_auth( + origin, event, context, auth_events + ) + except Exception: + # We don't really mind if the above fails, so lets not fail + # processing if it does. However, it really shouldn't fail so + # let's still log as an exception since we'll still want to fix + # any bugs. + logger.exception( + "Failed to double check auth events for %s with remote. " + "Ignoring failure and continuing processing of event.", + event.event_id, + ) + try: self.auth.check(room_version, event, auth_events=auth_events) except AuthError as e: @@ -2042,6 +2055,15 @@ class FederationHandler(BaseHandler): ): """Helper for do_auth. See there for docs. + Checks whether a given event has the expected auth events. If it + doesn't then we talk to the remote server to compare state to see if + we can come to a consensus (e.g. if one server missed some valid + state). + + This attempts to resovle any potential divergence of state between + servers, but is not essential and so failures should not block further + processing of the event. + Args: origin (str): event (synapse.events.EventBase): @@ -2088,9 +2110,15 @@ class FederationHandler(BaseHandler): missing_auth, ) try: - remote_auth_chain = yield self.federation_client.get_event_auth( - origin, event.room_id, event.event_id - ) + try: + remote_auth_chain = yield self.federation_client.get_event_auth( + origin, event.room_id, event.event_id + ) + except RequestSendFailed as e: + # The other side isn't around or doesn't implement the + # endpoint, so lets just bail out. + logger.info("Failed to get event auth from remote: %s", e) + return seen_remotes = yield self.store.have_seen_events( [e.event_id for e in remote_auth_chain] @@ -2236,12 +2264,18 @@ class FederationHandler(BaseHandler): try: # 2. Get remote difference. - result = yield self.federation_client.query_auth( - origin, - event.room_id, - event.event_id, - local_auth_chain, - ) + try: + result = yield self.federation_client.query_auth( + origin, + event.room_id, + event.event_id, + local_auth_chain, + ) + except RequestSendFailed as e: + # The other side isn't around or doesn't implement the + # endpoint, so lets just bail out. + logger.info("Failed to query auth from remote: %s", e) + return seen_remotes = yield self.store.have_seen_events( [e.event_id for e in result["auth_chain"]] diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py index 6209858bbb..e49c8203ef 100644 --- a/synapse/handlers/presence.py +++ b/synapse/handlers/presence.py @@ -828,14 +828,17 @@ class PresenceHandler(object): # joins. continue - event = yield self.store.get_event(event_id) - if event.content.get("membership") != Membership.JOIN: + event = yield self.store.get_event(event_id, allow_none=True) + if not event or event.content.get("membership") != Membership.JOIN: # We only care about joins continue if prev_event_id: - prev_event = yield self.store.get_event(prev_event_id) - if prev_event.content.get("membership") == Membership.JOIN: + prev_event = yield self.store.get_event(prev_event_id, allow_none=True) + if ( + prev_event + and prev_event.content.get("membership") == Membership.JOIN + ): # Ignore changes to join events. continue diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py index 0e92b405ba..7ad16c8566 100644 --- a/synapse/handlers/stats.py +++ b/synapse/handlers/stats.py @@ -115,6 +115,7 @@ class StatsHandler(StateDeltasHandler): event_id = delta["event_id"] stream_id = delta["stream_id"] prev_event_id = delta["prev_event_id"] + stream_pos = delta["stream_id"] logger.debug("Handling: %r %r, %s", typ, state_key, event_id) @@ -136,10 +137,15 @@ class StatsHandler(StateDeltasHandler): event_content = {} if event_id is not None: - event_content = (yield self.store.get_event(event_id)).content or {} + event = yield self.store.get_event(event_id, allow_none=True) + if event: + event_content = event.content or {} + + # We use stream_pos here rather than fetch by event_id as event_id + # may be None + now = yield self.store.get_received_ts_by_stream_pos(stream_pos) # quantise time to the nearest bucket - now = yield self.store.get_received_ts(event_id) now = (now // 1000 // self.stats_bucket_size) * self.stats_bucket_size if typ == EventTypes.Member: @@ -149,9 +155,11 @@ class StatsHandler(StateDeltasHandler): # compare them. prev_event_content = {} if prev_event_id is not None: - prev_event_content = ( - yield self.store.get_event(prev_event_id) - ).content + prev_event = yield self.store.get_event( + prev_event_id, allow_none=True, + ) + if prev_event: + prev_event_content = prev_event.content membership = event_content.get("membership", Membership.LEAVE) prev_membership = prev_event_content.get("membership", Membership.LEAVE) diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index b878ce11dc..62fda0c664 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -597,15 +597,28 @@ class SyncHandler(object): if canonical_alias and canonical_alias.content.get("alias"): defer.returnValue(summary) + me = sync_config.user.to_string() + joined_user_ids = [ - r[0] for r in details.get(Membership.JOIN, empty_ms).members + r[0] + for r in details.get(Membership.JOIN, empty_ms).members + if r[0] != me ] invited_user_ids = [ - r[0] for r in details.get(Membership.INVITE, empty_ms).members + r[0] + for r in details.get(Membership.INVITE, empty_ms).members + if r[0] != me ] gone_user_ids = ( - [r[0] for r in details.get(Membership.LEAVE, empty_ms).members] + - [r[0] for r in details.get(Membership.BAN, empty_ms).members] + [ + r[0] + for r in details.get(Membership.LEAVE, empty_ms).members + if r[0] != me + ] + [ + r[0] + for r in details.get(Membership.BAN, empty_ms).members + if r[0] != me + ] ) # FIXME: only build up a member_ids list for our heroes @@ -620,22 +633,13 @@ class SyncHandler(object): member_ids[user_id] = event_id # FIXME: order by stream ordering rather than as returned by SQL - me = sync_config.user.to_string() if (joined_user_ids or invited_user_ids): summary['m.heroes'] = sorted( - [ - user_id - for user_id in (joined_user_ids + invited_user_ids) - if user_id != me - ] + [user_id for user_id in (joined_user_ids + invited_user_ids)] )[0:5] else: summary['m.heroes'] = sorted( - [ - user_id - for user_id in gone_user_ids - if user_id != me - ] + [user_id for user_id in gone_user_ids] )[0:5] if not sync_config.filter_collection.lazy_load_members(): diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py index 27e7cbf3cc..babbf6a23c 100644 --- a/synapse/rest/client/versions.py +++ b/synapse/rest/client/versions.py @@ -39,6 +39,7 @@ class VersionsRestServlet(RestServlet): "r0.2.0", "r0.3.0", "r0.4.0", + "r0.5.0", ], # as per MSC1497: "unstable_features": { diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py index 1782428048..cc7df5cf14 100644 --- a/synapse/storage/events_worker.py +++ b/synapse/storage/events_worker.py @@ -78,6 +78,43 @@ class EventsWorkerStore(SQLBaseStore): desc="get_received_ts", ) + def get_received_ts_by_stream_pos(self, stream_ordering): + """Given a stream ordering get an approximate timestamp of when it + happened. + + This is done by simply taking the received ts of the first event that + has a stream ordering greater than or equal to the given stream pos. + If none exists returns the current time, on the assumption that it must + have happened recently. + + Args: + stream_ordering (int) + + Returns: + Deferred[int] + """ + + def _get_approximate_received_ts_txn(txn): + sql = """ + SELECT received_ts FROM events + WHERE stream_ordering >= ? + LIMIT 1 + """ + + txn.execute(sql, (stream_ordering,)) + row = txn.fetchone() + if row and row[0]: + ts = row[0] + else: + ts = self.clock.time_msec() + + return ts + + return self.runInteraction( + "get_approximate_received_ts", + _get_approximate_received_ts_txn, + ) + @defer.inlineCallbacks def get_event( self, |